阅读说明：本技术 切晶粘晶膜、以及使用了该切晶粘晶膜的半导体封装及其制造方法 (Die-cut die-bonding film, semiconductor package using the die-cut die-bonding film, and method for manufacturing the semiconductor package ) 是由 森田稔 于 2020-11-06 设计创作，主要内容包括：一种切晶粘晶膜,其是粘接剂层与粘合剂层层积而成的切晶粘晶膜,其特征在于,上述粘接剂层是含有环氧树脂(A)、环氧树脂固化剂(B)、苯氧基树脂(C)和无机填充材料(D)的膜状粘接剂的层,上述苯氧基树脂(C)在25℃的弹性模量为500MPa以上,上述粘接剂层中,上述苯氧基树脂(C)在上述环氧树脂(A)与上述苯氧基树脂(C)的各含量的合计中所占的比例为10～60质量％,上述粘接剂层与上述粘合剂层在25～80℃范围内的剥离力为0.40N/25mm以下,上述粘接剂层的热固化后的导热系数为1.0W/m·K以上。(A die-cut die-bond film comprising an adhesive layer and an adhesive layer laminated together, wherein the adhesive layer is a film-like adhesive comprising an epoxy resin (A), an epoxy resin curing agent (B), a phenoxy resin (C) and an inorganic filler (D), the phenoxy resin (C) has an elastic modulus at 25 ℃ of 500MPa or more, the ratio of the phenoxy resin (C) to the sum of the contents of the epoxy resin (A) and the phenoxy resin (C) in the adhesive layer is 10 to 60% by mass, the peel strength between the adhesive layer and the adhesive layer is 0.40N/25mm or less at 25 to 80 ℃, and the thermal conductivity of the adhesive layer after thermosetting is 1.0W/m.K or more.)

1. A die-cut die-bonded film comprising an adhesive layer and an adhesive layer laminated on each other,

the adhesive layer is a film-like adhesive layer containing an epoxy resin (A), an epoxy resin curing agent (B), a phenoxy resin (C) and an inorganic filler (D),

the phenoxy resin (C) has an elastic modulus at 25 ℃ of 500MPa or more,

in the adhesive layer, the ratio of the phenoxy resin (C) to the total content of the epoxy resin (A) and the phenoxy resin (C) is 10-60 mass%,

the peeling force between the adhesive layer and the adhesive layer is less than 0.40N/25mm within the range of 25-80 ℃,

the thermal conductivity of the adhesive layer after heat curing is 1.0W/mK or more.

2. The die-cut crystal-bonded film according to claim 1, wherein when the adhesive layer is heated from 25 ℃ at a heating rate of 5 ℃/min, the pre-curing elastic modulus G' in the range of 25 to 80 ℃ is 10kPa or more.

3. The die-cut crystal-bonded film according to claim 1 or 2, wherein when the adhesive layer is heated from 25 ℃ at a heating rate of 5 ℃/min, the melt viscosity at 120 ℃ is in the range of 500 to 10000 Pa-s.

4. The die-cut crystalline film according to any one of claims 1 to 3, wherein the adhesive layer is energy ray curable.

5. A method for manufacturing a semiconductor package, comprising the steps of:

a step 1 of providing the die bond film according to any one of claims 1 to 4 on the back surface of a semiconductor wafer having at least 1 semiconductor circuit formed on the front surface thereof by thermal compression bonding so that the adhesive layer is in contact with the back surface of the semiconductor wafer;

a step 2 of simultaneously dicing the semiconductor wafer and the adhesive layer to obtain semiconductor chips with an adhesive layer, each of which includes the semiconductor chips and the adhesive layer, on the adhesive layer;

a 3 rd step of removing the adhesive layer from the adhesive layer and thermocompression bonding the semiconductor chip with the adhesive layer and the wiring board via the adhesive layer; and

and a 4 th step of thermally curing the adhesive layer.

6. A semiconductor package, wherein a semiconductor chip and a wiring board or a semiconductor chip are bonded together by a thermosetting body of an adhesive layer provided on a die-cut die-bonding film according to any one of claims 1 to 4.

Technical Field

The present invention relates to a die-cut die-bond film, a semiconductor package using the die-cut die-bond film, and a method for manufacturing the semiconductor package.

Background

In recent years, with the progress of miniaturization, higher functionality, and higher functionality of electronic devices, higher functionality and higher functionality have been advanced in semiconductor packages mounted therein, and the miniaturization of wiring rules of semiconductor chips has been advanced. Along with the development of higher functions and higher functions, a stacked MCP (Multi Chip Package) in which semiconductor chips are stacked in multiple layers has become popular, and such stacked MCP is mounted in a memory Package for a mobile phone or a portable audio device. Further, with the increase in the number of functions of mobile phones and the like, the density and integration of packages have been increasing. Along with this, the multilayer stacking of semiconductor chips is further advancing.

In the process of manufacturing such a memory package, a film-like adhesive (die attach film) is used for bonding a wiring board and a semiconductor chip and bonding between semiconductor chips (so-called die attach), and the die attach film needs to be thinned as the chips are stacked in multiple layers. In recent years, the miniaturization of the wiring rule of the wafer has been advanced, and heat is more likely to be generated on the surface of the semiconductor element. Therefore, in order to facilitate heat dissipation to the outside of the package, the demand for high thermal conductivity of these die attach films is increasing.

As the thermally conductive crystal-bonded film, a film using a thermally conductive filler is generally designed.

As a material that can be used as a thermally conductive crystal-bonded film, for example, patent document 1 describes an adhesive sheet used as a crystal-bonded film, which includes: an average particle diameter of 2 to 9 μm and a specific surface area of 0.8 to 8.0m²A spherical alumina filler per gram; and a resin component containing a high molecular weight component and a low molecular weight component in a specific weight content ratio. According to the technique described in patent document 1, it is considered that the use of the adhesive sheet improves embeddability in the uneven portion of the adherend, and suppresses the generation of voids.

Patent document 2 describes the following: in a crystal-cut crystal-bonded film formed by sequentially laminating a crystal-bonded layer, a bonding layer and a base material layer, the picking-up instability can be improved by controlling the stripping force of the crystal-bonded layer and the bonding layer at normal temperature and high temperature.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6366228

Patent document 2: japanese laid-open patent application No. 2010-232422

Disclosure of Invention

Problems to be solved by the invention

The present inventors have made extensive studies to improve the productivity of a semiconductor device in the dicing-picking-up step of a semiconductor wafer using a die-cut die-bonded film obtained by laminating a thermally conductive adhesive layer (thermally conductive die-bonded film) and an adhesive layer (die-cut film). As a result, it was found that: after a semiconductor wafer is diced by dicing, a thermally conductive die attach film is left on the back surface of the wafer and peeled off from a die cut film by using a pick-up collet (pick-up collet), and the wafer is thermally bonded to a wiring board, and the pick-up collet stores heat while repeating the above steps; in addition, when the chip is picked up using the pickup collet having stored heat, heat is also transferred to the dicing film via the die bond film having a high thermal conductivity, so that the peeling property between the die bond film and the dicing film is reduced, and a pickup failure is likely to occur.

The invention provides a crystal-cut and crystal-bonded film, which is formed by laminating a heat-conducting crystal-cut film and a crystal-cut film, wherein in a picking-up process in semiconductor processing, even if a picking-up collet stores heat, picking-up defects are not easy to occur, and in addition, the generation of gaps in the process of thermocompression bonding on a wiring substrate can be inhibited.

Means for solving the problems

The present inventors have made extensive studies in view of the above-mentioned problems, and as a result, have found that a thermally conductive crystal-bonded film containing an inorganic filler is produced by incorporating a phenoxy resin as a constituent material of the crystal-bonded film, and that the releasability from a dicing film in a pickup step is improved. Further, the present inventors have found that the above problems can be solved at a higher level and the crystallinity can be improved by using a crystalline adhesive film in which a substance exhibiting a constant or higher value of normal temperature (25 ℃) elastic modulus is used as a phenoxy resin, and the crystalline adhesive film is compounded with an epoxy resin and a curing agent thereof in specific amounts so that the thermal conductivity after thermal curing is controlled to be increased to a certain level or higher.

The present invention has been completed based on further repeated studies on these technical ideas.

The above object of the present invention can be achieved by the following means.

[1]

A die-cut die-bonded film comprising an adhesive layer and an adhesive layer laminated on each other,

the adhesive layer is a film-like adhesive layer containing an epoxy resin (A), an epoxy resin curing agent (B), a phenoxy resin (C) and an inorganic filler (D),

the phenoxy resin (C) has an elastic modulus at 25 ℃ of 500MPa or more,

the adhesive layer contains the phenoxy resin (C) in an amount of 10 to 60 mass% based on the total content of the epoxy resin (A) and the phenoxy resin (C),

the peeling force between the adhesive layer and the adhesive layer is less than 0.40N/25mm at the temperature of 25-80 ℃,

the thermal conductivity of the adhesive layer after heat curing is 1.0W/mK or more.

[2]

The die-cut crystal-bonded film according to [1], wherein when the adhesive layer is heated from 25 ℃ at a heating rate of 5 ℃/min, the pre-curing elastic modulus G' in the range of 25 to 80 ℃ is 10kPa or more.

[3]

The die-cut and die-bonded film according to [1] or [2], wherein the adhesive layer has a melt viscosity of 500 to 10000Pa · s at 120 ℃ when heated from 25 ℃ at a heating rate of 5 ℃/min.

[4]

The die-cut crystal-bonded film according to any one of [1] to [3], wherein the adhesive layer is curable by energy rays.

[5]

A method for manufacturing a semiconductor package, comprising the steps of:

a1 st step of providing the die-cut adhesive film according to any one of [1] to [4] on the back surface of a semiconductor wafer having at least 1 semiconductor circuit formed on the front surface thereof by thermal compression so that the adhesive layer is brought into contact with the back surface of the semiconductor wafer;

a 2 nd step of simultaneously dicing the semiconductor wafer and the adhesive layer to obtain semiconductor chips with an adhesive layer, each of which includes the semiconductor chips and the adhesive layer, on the adhesive layer;

a 3 rd step of removing the adhesive layer from the adhesive layer and thermocompression bonding the semiconductor chip with the adhesive layer and the wiring board via the adhesive layer; and

and a 4 th step of thermally curing the adhesive layer.

[6]

A semiconductor package, characterized in that a semiconductor chip is bonded to a wiring board or between semiconductor chips through a thermosetting body of an adhesive layer provided in the die-cut die-bonding film according to any one of [1] to [4 ].

In the present invention, the numerical range represented by the term "to" is a range including the numerical values described before and after the term "to" as the lower limit value and the upper limit value.

In the present invention, the (meth) acrylic acid means one or both of acrylic acid and methacrylic acid. The same applies to (meth) acrylates.

In the present invention, 1 kind of each component may be used, or 2 or more kinds may be mixed and used.

Effects of the invention

The die-cut die-bonding film of the present invention is formed by laminating a thermally conductive die-bonding film and a die-cut film, and is less likely to cause a pickup failure and has excellent die-bonding properties even when the pickup collet is in a heat-accumulated state in a pickup step in semiconductor processing.

Drawings

Fig. 1 is a schematic longitudinal sectional view showing a preferred embodiment of the 1 st step of the method for manufacturing a semiconductor package of the present invention.

Fig. 2 is a schematic longitudinal sectional view showing a preferred embodiment of the 2 nd process of the method for manufacturing a semiconductor package of the present invention.

Fig. 3 is a schematic longitudinal sectional view showing a preferred embodiment of the 3 rd step of the method for manufacturing a semiconductor package of the present invention.

Fig. 4 is a schematic longitudinal sectional view showing a preferred embodiment of a process of connecting bonding wires of the method of manufacturing a semiconductor package of the present invention.

Fig. 5 is a schematic longitudinal sectional view showing an example of a multilayer stack embodiment of the method for manufacturing a semiconductor package of the present invention.

Fig. 6 is a schematic longitudinal sectional view showing another multilayer stack embodiment example of the manufacturing method of the semiconductor package of the present invention.

Fig. 7 is a schematic longitudinal sectional view showing one preferred embodiment of a semiconductor package manufactured by the manufacturing method of a semiconductor package of the present invention.

Detailed Description

[ die-cut die-bonding film ]

The die-cut die-bonding film of the present invention is formed by laminating an adhesive layer (die-bonding film) and an adhesive layer (die-cut film). The die-cut die-bond film of the present invention may be a type in which a pressure-sensitive adhesive layer and an adhesive layer are provided on a substrate (also referred to as a substrate film) in this order, or a release film may be provided on the adhesive layer. The die-cut film and the die-bond film are also preferably in a specific shape as described in the production of the die-cut die-bond film.

The adhesive layer of the die-cut die-bonding film of the present invention is a layer of a film-like adhesive containing an epoxy resin (a), an epoxy resin curing agent (B), a phenoxy resin (C), and an inorganic filler (D).

The phenoxy resin (C) constituting the adhesive layer has a normal-temperature (25 ℃) elastic modulus of 500MPa or more, and the ratio of the phenoxy resin (C) in the adhesive layer to the total content of the epoxy resin (A) and the phenoxy resin (C) is 10 to 60 mass%.

In the die-cut die-bonding film of the present invention, the peel force (peel force before curing) between the adhesive layer and the pressure-sensitive adhesive layer is 0.40N/25mm or less at 25 to 80 ℃. The adhesive layer has a thermal conductivity of 1.0W/mK or more after heat curing.

The mode of each layer constituting the die bond film of the present invention will be explained in order.

< adhesive layer >

The adhesive layer constituting the die-cut die-bonded crystalline film of the present invention contains at least an epoxy resin (a), an epoxy resin curing agent (B), a phenoxy resin (C), and an inorganic filler (D).

(epoxy resin (A))

The epoxy resin (a) is not particularly limited as long as it is a thermosetting resin having an epoxy group, and may be any of liquid, solid, or semisolid. In the present invention, liquid means a softening point of less than 25 ℃, solid means a softening point of 60 ℃ or higher, and semisolid means a softening point between the softening point of the liquid and the softening point of the solid (25 ℃ or higher and less than 60 ℃). The epoxy resin (a) used in the present invention preferably has a softening point of 100 ℃ or less in order to obtain a film-like adhesive having a low melt viscosity in an appropriate temperature range (for example, 60 to 120 ℃). In the present invention, the softening point is a value measured by a softening point test (ring ball type) method (measurement conditions: in accordance with JIS-2817).

In the epoxy resin (a) used in the present invention, the epoxy equivalent is preferably 500g/eq or less, more preferably 150 to 450g/eq, from the viewpoint that the crosslinking density of the cured product becomes high, as a result, the probability of contact between the inorganic fillers (D) compounded becomes high, and the contact area becomes large, thereby obtaining a higher thermal conductivity. In the present invention, the epoxy equivalent means the number of grams (g/eq) of the resin containing 1 equivalent of epoxy group.

The weight average molecular weight of the epoxy resin (a) is generally preferably less than 10,000, more preferably 5,000 or less. The lower limit is not particularly limited, and is actually 300 or more.

The weight average molecular weight is a value obtained by GPC (gel permeation chromatography) analysis.

Examples of the skeleton of the epoxy resin (a) include phenol novolak type, o-cresol novolak type, dicyclopentadiene type, biphenyl type, fluorene bisphenol type, triazine type, naphthol type, naphthalenediphenol type, triphenylmethane type, tetraphenyl type, bisphenol a type, bisphenol F type, bisphenol AD type, bisphenol S type, and trimethylolmethane type. Among them, from the viewpoint of obtaining a film-like adhesive having low crystallinity of the resin and good appearance, triphenylmethane type, bisphenol a type, cresol novolak type, and o-cresol novolak type are preferable.

The content of the epoxy resin (a) in the adhesive layer used in the present invention (in the solid content (total amount excluding the solvent) of the adhesive layer-forming composition) is preferably 3 to 30% by mass, and more preferably 5 to 30% by mass. When the content is not less than the preferable lower limit, the thermal conductivity of the film-like adhesive can be further improved. On the other hand, by being equal to or less than the above preferable upper limit, the generation of oligomer components can be suppressed, and the change in the film state (film viscosity and the like) can be made difficult when the temperature is slightly changed.

(epoxy resin curing agent (B))

As the epoxy resin curing agent (B), any curing agent such as amines, acid anhydrides, polyhydric phenols and the like can be used. In the present invention, it is preferable to use a latent curing agent in view of producing an adhesive layer having high storage stability, which can exhibit curability at a high temperature exceeding a certain temperature while having a low melt viscosity in a desired temperature range and comprising the epoxy resin (a) and the phenoxy resin (C) described later, has quick curability, and can be stored at room temperature for a long period of time.

Examples of the latent curing agent include dicyandiamide compounds, imidazole compounds, curing catalyst complex-type polyhydric phenol compounds, hydrazide compounds, boron trifluoride-amine complexes, amine imide compounds, polyamine salts, and modified products thereof or microcapsule-type latent curing agents. The imidazole compound is more preferably used in terms of having more excellent latent properties (excellent stability at room temperature and property of exhibiting curability by heating) and a higher curing speed.

These can be used alone in 1, also can be used in 2 or more combinations.

The content of the epoxy resin curing agent (B) is preferably 0.5 to 100 parts by mass, more preferably 1 to 80 parts by mass, per 100 parts by mass of the epoxy resin (a). When the content is equal to or more than the preferable lower limit, the curing time can be further shortened, and when the content is equal to or less than the preferable upper limit, the excessive curing agent can be prevented from remaining in the film-like adhesive. As a result, the residual curing agent is inhibited from adsorbing moisture, and the reliability of the semiconductor device is improved.

(phenoxy resin (C))

The phenoxy resin (C) has an elastic modulus at room temperature (25 ℃) of 500MPa or more. The phenoxy resin (C) preferably has a normal-temperature (25 ℃) elastic modulus of 2000MPa or less. By using a phenoxy resin having such an elastic modulus, both the viscocrystallinity and the pickup property can be achieved at a higher level.

The normal temperature (25 ℃) elastic modulus (also referred to as "25 ℃ elastic modulus" in the present invention) can be determined by the method described in the examples below. The normal temperature (25 ℃) elastic modulus when the adhesive layer contains 2 or more kinds of phenoxy resins can be determined by using a film prepared by blending phenoxy resins at a mixing ratio to constitute the adhesive layer as a phenoxy resin film for measuring the normal temperature elastic modulus in the method described in the examples below. The normal temperature (25 ℃) elastic modulus is effective to one unit when the unit is MPa.

The weight average molecular weight of the phenoxy resin (C) is usually 10000 or more. The upper limit is not particularly limited, but is actually 5000000 or less. Among them, 10000 to 100000 are more preferable.

The weight average molecular weight of the phenoxy resin (C) is determined by conversion to polystyrene by GPC (Gel Permeation Chromatography).

The glass transition temperature (Tg) of the above phenoxy resin (C) is preferably less than 120 ℃, more preferably less than 100 ℃, and still more preferably less than 90 ℃. The lower limit is preferably 0 ℃ or higher, more preferably 10 ℃ or higher.

The glass transition temperature of the phenoxy resin (C) is a glass transition temperature measured by DSC (differential scanning calorimeter) at a temperature rise rate of 0.1 ℃/min.

The adhesive layer used in the present invention contains at least one phenoxy resin as the phenoxy resin (C).

In the present invention, the epoxy resin (a) and the phenoxy resin (C) are classified into the epoxy resin (a) having an epoxy equivalent (mass of the resin per 1 equivalent of epoxy group) of 500g/eq or less and the phenoxy resin (C) having an epoxy equivalent exceeding 500g/eq, respectively.

The phenoxy resin (C) can be obtained by the reaction of a bisphenol or a diphenol compound with an epihalohydrin such as epichlorohydrin, or the reaction of a liquid epoxy resin with a bisphenol or a diphenol compound.

In either reaction, as the bisphenol or biphenol compound, a compound represented by the following general formula (a) is preferred.

[ CHEM 1]

General formula (A)

In the general formula (A), L^aRepresents a single bond or a divalent linking group, R^a1And R^a2Each independently represents a substituent. ma and na each independently represent an integer of 0 to 4.

L^aIn (3), the divalent linking group is preferably alkylene, phenylene, -O-, -S-, -SO-, -SO₂Or a combination of alkylene and phenylene.

The number of carbon atoms of the alkylene group is preferably 1 to 10, more preferably 1 to 6, further preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1.

Alkylene is preferably-C (R)^α)(R^β) -a group as shown. Here, R^αAnd R^βEach independently represents a hydrogen atom, an alkyl group, or an aryl group. R^αAnd R^βMay be bonded to each other to form a ring. R^αAnd R^βPreferably a hydrogen atom or an alkyl group (e.g., methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, hexyl, octyl, 2-ethylhexyl). Among them, the alkylene group is preferably-CH₂-、-CH(CH₃) or-C (CH)₃)₂-, more preferably-CH₂-、-CH(CH₃) Further preferred is-CH₂-。

The number of carbon atoms of the phenylene group is preferably 6 to 12, more preferably 6 to 8, and further preferably 6. Examples of the phenylene group include p-phenylene, m-phenylene and o-phenylene, and p-phenylene and m-phenylene are preferable.

As the alkylene group and the phenylene group in the group in which the alkylene group and the phenylene group are combined, the description contents of the alkylene group and the phenylene group can be preferably applied, respectively.

The alkylene group and the phenylene group combined are preferably an alkylene-phenylene-alkylene group, and more preferably-C (R)^α)(R^β) -phenylene-C (R)^α)(R^β)-。

R^αAnd R^βThe ring formed by bonding is preferably a 5-or 6-membered ring, more preferablyA cyclopentane ring or a cyclohexane ring is selected, and a cyclohexane ring is more preferable.

L^aPreferably a single bond, alkylene, -O-or-SO₂More preferably an alkylene group.

R^a1And R^a2Preferably an alkyl group, an aryl group, an alkoxy group, an alkylthio group or a halogen atom, more preferably an alkyl group, an aryl group or a halogen atom, and still more preferably an alkyl group.

ma and na are preferably integers of 0 to 2, more preferably 0 or 1, and still more preferably 0.

Examples of the bisphenol or biphenol compound include bisphenol a, bisphenol AD, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z, or 4,4 ' -biphenol, 2 ' -dimethyl-4, 4 ' -biphenol, 2 ', 6,6 ' -tetramethyl-4, 4 ' -biphenol, Cardo skeleton type bisphenol, etc., and are preferably selected from bisphenol a, bisphenol AD, bisphenol C, bisphenol E, bisphenol F, and 4,4 ' -biphenol, more preferably selected from bisphenol a, bisphenol E, and bisphenol F, and particularly preferably bisphenol a.

The liquid epoxy resin is preferably a diglycidyl ether of an aliphatic diol compound, and more preferably a compound represented by the following general formula (B).

[ CHEM 2]

General formula (B)

In the general formula (B), X represents an alkylene group, and nb represents an average number of repetitions and represents 1 to 10.

The number of carbon atoms of the alkylene group is preferably 2 to 10, more preferably 2 to 8, further preferably 3 to 8, particularly preferably 4 to 6, and most preferably 6.

Examples thereof include ethylene, propylene, butylene, pentylene, hexylene and octylene, and ethylene, trimethylene, tetramethylene, pentamethylene, heptamethylene, hexamethylene or octamethylene is preferred.

nb is preferably 1 to 6, more preferably 1 to 3, and still more preferably 1.

When nb is 2 to 10, X is preferably an ethylene group or a propylene group, and more preferably an ethylene group.

Examples of the aliphatic diol compound in the diglycidyl ether include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-heptanediol, 1, 6-hexanediol, 1, 7-pentanediol, and 1, 8-octanediol.

In the above reaction, the bisphenol, the diphenol compound and the aliphatic diol compound may be each a phenoxy resin obtained by reacting alone or a phenoxy resin obtained by mixing two or more kinds of them. Mention may be made, for example, of the reaction of diglycidyl ether of 1, 6-hexanediol with a mixture of bisphenol A and bisphenol F.

In the present invention, the phenoxy resin (C) is preferably a phenoxy resin obtained by the reaction of a liquid epoxy resin with a bisphenol or a diphenol compound, and more preferably a phenoxy resin having a repeating unit represented by the following general formula (I).

[ CHEM 3]

General formula (I)

In the general formula (I), L^a、R^a1、R^a2Ma and na with L in the formula (A)^a、R^a1、R^a2Ma and na have the same meaning, and the preferred ranges are also the same. X and nb have the same meanings as those of X and nb in the general formula (B), and the preferable ranges are also the same.

Among these, polymers of diglycidyl ethers of bisphenol F and 1, 6-hexanediol are preferred in the present invention.

Further, the amount of epoxy groups remaining in a small amount in the phenoxy resin (C) is preferably more than 5000g/eq in terms of epoxy equivalent.

The phenoxy resin (C) can be synthesized by the above-described method, or a commercially available product can be used. Examples of commercially available products include 1256 (bisphenol A phenoxy resin, manufactured by Mitsubishi chemical corporation), YP-50 (bisphenol A phenoxy resin, manufactured by Nikkiso Epoxy Co., Ltd.), YP-70 (bisphenol A/F phenoxy resin, manufactured by Nikkiso Epoxy Co., Ltd.), FX-316 (bisphenol F phenoxy resin, manufactured by Nikkiso Epoxy Co., Ltd.), FX-280S (Cardo skeleton phenoxy resin, manufactured by Nikkiso chemical Co., Ltd.), 4250 (bisphenol A/F phenoxy resin, manufactured by Mitsubishi chemical corporation), and the like. Further, a low-elasticity high-heat-resistance phenoxy resin such as FX-310 (a low-elasticity high-heat-resistance phenoxy resin manufactured by Nikkiso Epoxy Co., Ltd.) can also be preferably used.

In the adhesive layer, the ratio of the phenoxy resin (C) to the total content of the epoxy resin (a) and the phenoxy resin (C) is 10 to 60 mass%, preferably 15 to 50 mass%, and more preferably 18 to 45 mass%.

(inorganic Filler (D))

The inorganic filler (D) is not particularly limited as long as it is an inorganic filler having thermal conductivity. The inorganic filler (D) imparts thermal conductivity to the adhesive layer.

The inorganic filler (D) is particles made of a heat conductive material or particles having a surface coated with a heat conductive material, and the heat conductivity of the heat conductive material is preferably 12W/m · K or more, and more preferably 30W/m · K or more.

When the thermal conductivity of the thermally conductive material is equal to or higher than the preferable lower limit, the amount of the inorganic filler (D) to be blended to obtain a target thermal conductivity can be reduced, an increase in melt viscosity of the adhesive layer can be suppressed, and embeddability in the uneven portion of the substrate when the substrate is pressed and bonded can be further improved. As a result, the generation of voids can be more reliably suppressed.

In the present invention, the thermal conductivity of the thermally conductive material is a thermal conductivity of 25 ℃, and literature values of the respective materials can be used. In the case where the document does not describe it, for example, the value measured according to JIS R1611 may be used instead if the thermally conductive material is ceramic, and the value measured according to JIS H7801 may be used instead if the thermally conductive material is metal.

The inorganic filler (D) is, for example, a thermally conductive ceramic, and preferably includes alumina particles (thermal conductivity: 36W/mK), aluminum nitride particles (thermal conductivity: 150 to 290W/mK), boron nitride particles (thermal conductivity: 60W/mK), zinc oxide particles (thermal conductivity: 54W/mK), silicon nitride filler (thermal conductivity: 27W/mK), silicon carbide particles (thermal conductivity: 200W/mK) and magnesium oxide particles (thermal conductivity: 59W/mK).

In particular, alumina particles are preferable in terms of high thermal conductivity, dispersibility, and availability. In addition, aluminum nitride particles and boron nitride particles have a higher thermal conductivity than alumina particles, and are preferable from this point of view. In the present invention, among them, alumina particles and aluminum nitride particles are preferable.

Further, particles whose surfaces are coated with a thermally conductive metal may be mentioned. For example, silicone resin particles and acrylic resin particles whose surfaces are coated with a metal such as silver (thermal conductivity: 429W/m.K), nickel (thermal conductivity: 91W/m.K) or gold (thermal conductivity: 329W/m.K) are preferable.

In particular, silicone resin particles whose surfaces are coated with silver are preferred from the viewpoint of stress relaxation and high heat resistance.

The inorganic filler (D) may be surface-treated or surface-modified, and examples of the compound for carrying out such surface treatment or surface modification include a silane coupling agent, phosphoric acid or a phosphoric acid compound, a surfactant, and the like. In addition to the matters described in the present specification, for example, the descriptions of the silane coupling agent, phosphoric acid or a phosphoric acid compound, and the surfactant in the item of the heat conductive filler of international publication No. 2018/203527 or the item of the aluminum nitride filler of international publication No. 2017/158994 can be applied.

As a method for blending the inorganic filler (D) into the resin components such as the epoxy resin (a), the epoxy resin curing agent (B), and the phenoxy resin (C), there can be used: a method of directly mixing a powdery inorganic filler with a silane coupling agent, phosphoric acid or a phosphoric acid compound, and a surfactant as required (bulk blending method); or a method of dispersing an inorganic filler treated with a surface treatment agent such as a silane coupling agent, phosphoric acid or a phosphoric acid compound, or a surfactant in an organic solvent and mixing the inorganic filler in the form of a slurry.

The method for treating the inorganic filler (D) with a silane coupling agent is not particularly limited, and examples thereof include: a wet method of mixing the inorganic filler (D) and the silane coupling agent in a solvent; a dry method of treating the inorganic filler (D) and the silane coupling agent in a gas phase; the above bulk blending method; and the like.

In particular, aluminum nitride particles contribute to high thermal conductivity, but are likely to generate ammonium ions by hydrolysis, and therefore, it is preferable to use them together with a phenol resin having a low moisture absorption rate or to suppress hydrolysis by surface modification. As a method for modifying the surface of the aluminum nitride particles, the following methods are particularly preferred: an alumina oxide layer is provided on the surface layer to improve water resistance, and affinity with a resin is improved by surface treatment with phosphoric acid or a phosphoric acid compound.

It is also preferable to surface-treat the surface of the inorganic filler (D) with a silane coupling agent.

In addition, it is also preferable to further use an ion scavenger.

The silane coupling agent is a compound in which at least 1 hydrolyzable group such as alkoxy or aryloxy is bonded to a silicon atom, and in addition, an alkyl group, an alkenyl group, or an aryl group may be bonded. The alkyl group is preferably an alkyl group substituted with an amino group, an alkoxy group, an epoxy group or a (meth) acryloyloxy group, and more preferably an alkyl group substituted with an amino group (preferably a phenylamino group), an alkoxy group (preferably a glycidoxy group) or a (meth) acryloyloxy group.

Examples of the silane coupling agent include 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, glycidoxypropylmethyldiethoxysilane, glycidylmethoxysilane, and the like, 3-methacryloxypropyltriethoxysilane, and the like.

The silane coupling agent and the surfactant are preferably contained in an amount of 0.1 to 2.0 parts by mass per 100 parts by mass of the inorganic filler (D).

When the content of the silane coupling agent and the surfactant is in the above-described preferable range, the aggregation of the inorganic filler (D) can be suppressed, and the peeling at the bonding interface and the generation of voids due to volatilization of the excessive silane coupling agent and the surfactant in the semiconductor assembly heating step (for example, reflow step) can be suppressed, whereby the adhesiveness can be improved.

The shape of the inorganic filler (D) may be in the form of a flake, needle, fibril, sphere, or flake, and spherical particles are preferred in view of high filling and fluidity.

The inorganic filler (D) preferably has an average particle diameter (D50) of 0.1 to 3.5 μm. The average particle diameter (d50) is a so-called median diameter, and is a particle diameter at which 50% of particles are accumulated in a cumulative distribution when the total volume of the particles is 100%, as measured by a laser diffraction scattering method.

The adhesive layer used in the present invention has a content of the inorganic filler (D) in the total content of the epoxy resin (a), the epoxy resin curing agent (B), the phenoxy resin (C), and the inorganic filler (D) of 30 to 70 vol%. When the content ratio of the inorganic filler (D) is not less than the lower limit, a desired thermal conductivity and melt viscosity can be imparted to the film-like adhesive, an effect of heat dissipation from the semiconductor package can be obtained, and a defective overflow of the film-like adhesive can be suppressed. When the amount is equal to or less than the upper limit, a desired melt viscosity can be imparted to the film-like adhesive, and the occurrence of voids can be suppressed. In addition, internal stress generated in the semiconductor package during thermal change can be relaxed, and the adhesive strength can be improved.

The proportion of the inorganic filler (D) in the total content of the components (a) to (D) is preferably 20 to 60% by volume, more preferably 20 to 50% by volume.

The content (% by volume) of the inorganic filler (D) can be calculated from the content mass and specific gravity of each of the components (a) to (D).

(other Components)

The adhesive layer used in the present invention may contain a polymer compound in addition to the epoxy resin (a), the epoxy resin curing agent (B), the phenoxy resin (C), and the inorganic filler (D) within a range not impairing the effects of the present invention.

Examples of the polymer compound include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, silicone rubber, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid copolymer, an ethylene- (meth) acrylate copolymer, a polybutadiene resin, a polycarbonate resin, a thermoplastic polyimide resin, a polyamide resin such as 6-nylon or 6, 6-nylon, (meth) acrylic resins, a polyester resin such as polyethylene terephthalate or polybutylene terephthalate, a polyamideimide resin, and a fluororesin. These polymer compounds may be used alone or in combination of two or more.

The adhesive layer used in the present invention may further contain an ion trapping agent (ion trapping agent), a curing catalyst, a viscosity modifier, an antioxidant, a flame retardant, a colorant, and the like. For example, other additives of International publication No. 2017/158994 may be included.

The total content of the epoxy resin (a), the epoxy resin curing agent (B), the phenoxy resin (C), and the inorganic filler (D) in the adhesive layer used in the present invention may be, for example, 60 mass% or more, preferably 70 mass% or more, more preferably 80 mass% or more, or may be 90 mass% or more. The above ratio may be 100% by mass or less and may be 95% by mass or less.

(characteristics of adhesive layer)

Thermal conductivity after thermal curing

The adhesive layer used in the present invention has a thermal conductivity of 1.0W/mK or more after thermosetting. The thermal conductivity is preferably 1.4W/mK or more. If the thermal conductivity is less than the lower limit, the generated heat tends to be hardly released to the outside of the package. By allowing the thermally conductive film-like adhesive of the present invention to exhibit such an excellent thermal conductivity after thermosetting, the thermally conductive film-like adhesive of the present invention is brought into close contact with an adherend such as a semiconductor wafer or a wiring board and thermally cured, whereby a semiconductor package having improved heat dissipation efficiency to the outside of the semiconductor package can be obtained.

The upper limit of the thermal conductivity is not particularly limited, and is usually 30W/m.K or less.

Here, the post-heat curing in the measurement of the thermal conductivity means a state in which the curing of the adhesive layer is completed. Specifically, the reaction heat peak is disappeared when the temperature is measured by DSC (differential scanning calorimeter) at a temperature rise rate of 10 ℃/min.

In the present invention, the thermal conductivity of the adhesive layer after heat curing is a value obtained by measuring the thermal conductivity by the heat flow meter method (in accordance with JIS-A1412) using a thermal conductivity measuring apparatus (trade name: HC-110, manufactured by Yinzhong Seiki K.K.). Specifically, the measurement method described in examples can be referred to. The thermal conductivity is effective to 1 decimal place when the unit is W/m.K.

The thermal conductivity may be adjusted to the above range depending on the type and content of the compound or resin in which the epoxy resin (a), the epoxy resin curing agent (B), the phenoxy resin (C), and the like coexist, in addition to the content and the type of the inorganic filler (D). In this connection, the elastic modulus and melt viscosity before curing described below are also the same.

Modulus of elasticity before curing

In the adhesive layer used in the present invention, when the temperature of the adhesive layer before thermosetting is raised from 25 ℃ at a temperature raising rate of 5 ℃/min from the viewpoint of improving the pickup property, the pre-curing elastic modulus G' in the range of 25 to 80 ℃ is preferably 10kPa or more. Under the above measurement conditions, the pre-cure elastic modulus at 25 ℃ is preferably 400kPa or more, more preferably 450kPa or more, further preferably 500kPa or more, and also preferably 600kPa or more. Under the above measurement conditions, the pre-cure elastic modulus at 80 ℃ is preferably 12kPa or more, more preferably 15kPa or more, and still more preferably 20kPa or more.

The modulus of elasticity G' before curing can be determined by the method described in the examples described below. The elastic modulus G' before curing is effective to one unit when the unit is kPa.

In the present invention, the adhesive layer before thermosetting means an adhesive layer which is not exposed to a temperature condition of 25 ℃ or higher after the adhesive layer is formed. The die-cut die-bond film of the present invention is usually stored at a temperature of 10 ℃ or lower, and therefore, the adhesive layer before thermosetting is usually an adhesive layer stored (stored) at a temperature of 10 ℃ or lower after the adhesive layer is formed.

(melt viscosity)

In the adhesive layer used in the present invention, when the temperature of the adhesive layer before thermosetting is raised from 25 ℃ at a temperature raising rate of 5 ℃/min from the viewpoint of improving crystallinity, the melt viscosity at 120 ℃ is preferably in the range of 500 to 10000Pa · s, more preferably in the range of 1000 to 10000Pa · s, and further preferably in the range of 1500 to 9200Pa · s.

The melt viscosity can be determined by the method described in the examples below. The melt viscosity is effective to ten positions when Pa · s is used for a unit.

(formation of adhesive layer)

The adhesive layer used in the present invention can be formed by preparing an adhesive layer-forming composition (varnish) containing the adhesive layer-constituting component, applying the composition to a release-treated release film, and drying the release-treated release film. The adhesive layer-forming composition usually contains a solvent.

The thickness of the adhesive layer is preferably 200 μm or less, more preferably 100 μm or less, further preferably 50 μm or less, further preferably 30 μm or less, and further preferably 20 μm or less. The thickness of the adhesive layer is usually 1 μm or more, preferably 2 μm or more, and may be 4 μm or more.

The thickness of the film-like adhesive can be measured by a contact/linear meter method (a table-top contact thickness measuring device).

The release film subjected to the release treatment may be any film that functions as a coating film of the obtained film-like adhesive, and a known release film may be suitably used. Examples thereof include polypropylene (PP) subjected to mold release treatment, Polyethylene (PE) subjected to mold release treatment, and polyethylene terephthalate (PET) subjected to mold release treatment. As the coating method, a known method can be suitably used, and examples thereof include a method using a roll coater, a gravure coater, a die coater, a reverse coater, and the like.

The arithmetic mean roughness Ra of the surface of the adhesive layer to be bonded to the wafer is preferably 3.0 μm or less, and more preferably 3.0 μm or less on either surface to be bonded to the adherend.

The arithmetic average roughness Ra is more preferably 2.0 μm or less, and still more preferably 1.5 μm or less. The lower limit is not particularly limited, and is practically 0.1 μm or more.

< adhesive layer >

The pressure-sensitive adhesive layer constituting the die-cut and die-bonded film of the present invention and the method for forming the same can be suitably applied to general structures and methods for die-cut films (die-cut tapes). As the adhesive constituting the adhesive layer, general adhesives used for adhesive film applications, for example, acrylic adhesives, rubber adhesives, and the like can be suitably used. Among them, the adhesive layer is preferably energy ray-curable.

Examples of the acrylic pressure-sensitive adhesive include resins composed of (meth) acrylic acid and esters thereof, copolymers of (meth) acrylic acid and esters thereof and unsaturated monomers copolymerizable therewith (e.g., vinyl acetate, styrene, acrylonitrile, etc.), and the like. Two or more of these resins may be used in combination. Among them, as the constituent component, a copolymer containing 1 or more selected from methyl (meth) acrylate, ethylhexyl (meth) acrylate and butyl (meth) acrylate and 1 or more selected from hydroxyethyl (meth) acrylate and vinyl acetate is preferable. This facilitates control of adhesion and adhesiveness to the adherend.

In order to make the pressure-sensitive adhesive layer used in the present invention energy ray-curable, a polymerizable group (for example, a carbon-carbon unsaturated bond) may be introduced into a polymer constituting the pressure-sensitive adhesive layer, or a polymerizable monomer may be blended into the pressure-sensitive adhesive layer. The polymerizable monomer preferably has 2 or more (preferably 3 or more) polymerizable groups. That is, the energy ray curability means that the resin composition has a property of being cured by irradiation with an energy ray.

Examples of the energy ray include ultraviolet rays and electron beams.

As the adhesive layer used in the present invention, for example, the descriptions of japanese patent laid-open nos. 2010-232422, 2661950, 2002-226796 and 2005-303275 can be cited.

The thickness of the adhesive layer is preferably 1 to 200 μm, more preferably 2 to 100 μm, further preferably 3 to 50 μm, and further preferably 5 to 30 μm.

In the crystal-cut and crystal-bonded film, the peeling force between the adhesive layer and the adhesive layer within the range of 25-80 ℃ is less than 0.40N/25 mm. When the pressure-sensitive adhesive layer is energy-ray curable, the peel force is the peel force between the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer after irradiation with an energy ray. The peel force between the adhesive layer and the pressure-sensitive adhesive layer at 25 ℃ is preferably 0.30N/25mm or less, more preferably 0.20N/25mm or less. Further, the peel force between the adhesive layer and the pressure-sensitive adhesive layer at 80 ℃ is preferably 0.35N/25mm or less.

The peeling force can be determined by the method described in examples. The above peeling force is effective to two decimal places when the unit is N/25 mm.

< preparation of die-cut die-bonding film >

The method for producing the sliced and crystal-bonded film of the present invention is not particularly limited as long as it can form a structure in which an adhesive layer and an adhesive layer are laminated.

For example, a coating liquid containing a pressure-sensitive adhesive is applied to a release liner subjected to release treatment and dried to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is bonded to a base film, thereby producing a film (dicing film) in which the base film, the pressure-sensitive adhesive layer, and the release liner are sequentially stacked. Further, the composition for forming an adhesive layer was applied to a release film and dried to form an adhesive layer on the release film, thereby producing a crystal-bonded film. Next, the dicing film and the die bond film are bonded so that the pressure-sensitive adhesive layer exposed by peeling the release liner comes into contact with the pressure-sensitive adhesive layer, whereby a dicing die bond film in which the base film, the pressure-sensitive adhesive layer, and the release film are sequentially stacked can be obtained.

The bonding of the dicing film and the die bonding film is preferably performed under a pressurized condition.

In the bonding of the dicing film and the die bonding film, the shape of the dicing film is not particularly limited as long as the dicing film can cover the opening of the ring frame, and is preferably circular, and the shape of the die bonding film is not particularly limited as long as the die bonding film can cover the back surface of the wafer, and is preferably circular. The dicing film is preferably larger than the die bonding film and has a portion where the adhesive layer is exposed around the adhesive layer. In this manner, the die-cut film and the die-bond film cut into a desired shape are preferably bonded to each other.

The dicing die-bonding film thus produced was used after peeling the release film.

[ semiconductor Package and method for manufacturing the same ]

Next, preferred embodiments of the semiconductor package and the method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. In the following description and the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted. Fig. 1 to 7 are schematic longitudinal sectional views showing a preferred embodiment of each step of the method for manufacturing a semiconductor package of the present invention.

In the method for manufacturing a semiconductor package of the present invention, first, as the 1 st step, as shown in fig. 1, the dicing die-bonding film of the present invention is thermocompression bonded to one side of the adhesive layer (that is, the adhesive layer is thermocompression bonded so as to be in contact with the back surface of the semiconductor wafer) on the back surface of the semiconductor wafer 1 having at least 1 semiconductor circuit formed on the front surface (that is, the surface of the semiconductor wafer 1 on which the semiconductor circuit is not formed), and the adhesive layer 2 and the adhesive layer 3 are sequentially provided on the semiconductor wafer 1. The adhesive layer 2 shown in fig. 1 is smaller than the adhesive layer 3, but the size (area) of the two layers may be appropriately set according to the purpose. The thermocompression bonding conditions are performed at a temperature at which the epoxy resin (a) is not substantially thermally cured. For example, the conditions may be 70 ℃ and a pressure of 0.3 MPa.

As the semiconductor wafer 1, a semiconductor wafer having at least 1 semiconductor circuit formed on the surface thereof can be suitably used, and examples thereof include a silicon wafer, a SiC wafer, a GaAs wafer, and a GaN wafer. In order to provide the die-cut die-bond film of the present invention on the back surface of the semiconductor wafer 1, a known apparatus such as a roll laminator or a manual laminator can be suitably used.

Next, as a 2 nd step, as shown in fig. 2, the semiconductor wafer 1 and the adhesive layer 2 are simultaneously diced, thereby obtaining an adhesive layer-equipped semiconductor chip 5 including a semiconductor chip 4 and the adhesive layer 2 on the adhesive layer 3. The dicing tape (not shown) is not particularly limited, and a known dicing tape can be suitably used. The device (not shown) used for cutting is not particularly limited, and a known cutting device can be suitably used.

Next, as a 3 rd step, the adhesive layer is cured by an energy ray as necessary to reduce the adhesive strength, and after the adhesive layer 3 is removed from the adhesive layer 2 by picking up or the like, the semiconductor chip 5 with the adhesive layer is thermocompression bonded to the wiring board 6 via the adhesive layer 2, and the semiconductor chip 5 with the adhesive layer is mounted on the wiring board 6, as shown in fig. 3. As the wiring board 6, a board having a semiconductor circuit formed on a surface thereof can be suitably used, and examples thereof include a Printed Circuit Board (PCB), various lead frames, and a board having an electronic component such as a resistor or a capacitor mounted on a surface thereof.

The method for mounting the semiconductor chip 5 with an adhesive layer on the wiring board 6 is not particularly limited, and any conventional method capable of adhering the semiconductor chip 5 with an adhesive layer to the wiring board 6 or an electronic component mounted on the surface of the wiring board 6 with the adhesive layer 2 can be suitably used.

Next, as a 4 th step, the adhesive layer 2 is thermally cured. The temperature of the thermosetting is not particularly limited as long as it is not lower than the thermosetting start temperature of the adhesive layer 2, and varies depending on the types of the epoxy resin (a), phenoxy resin (C) and epoxy curing agent (B) used, but is not limited to 100 to 180 ℃, for example, and is more preferably 140 to 180 ℃ in view of curing at a higher temperature in a short time. If the temperature is less than the thermosetting initiation temperature, thermosetting cannot proceed, and the strength of the adhesive layer 2 tends to decrease, while if it exceeds the upper limit, the epoxy resin, the curing agent, the additive, and the like in the adhesive layer 2 volatilize during curing and tend to foam easily. The time for the curing treatment is preferably 10 to 120 minutes, for example.

Next, in the method for manufacturing a semiconductor package of the present invention, as shown in fig. 4, it is preferable that the wiring board 6 and the semiconductor chip 5 with an adhesive layer are connected via bonding wires 7. Such a connection method is not particularly limited, and conventionally known methods such as a wire Bonding method, a TAB (Tape Automated Bonding) method, and the like can be appropriately used.

Further, 2 or more semiconductor chips 4 may be stacked on the surface of the mounted semiconductor chip 4 by thermocompression bonding or thermosetting the other semiconductor chip 4, and connecting the semiconductor chip to the wiring board 6 again by the wire bonding method. For example, there is a method of stacking semiconductor chips while shifting them as shown in fig. 5; or a method of laminating the adhesive layers 2 after the 2 nd layer while embedding the bonding wires 7 by thickening the adhesive layers as shown in fig. 6; and the like.

In the method for manufacturing a semiconductor package according to the present invention, it is preferable that the wiring board 6 and the semiconductor chip 5 with an adhesive layer are sealed with a sealing resin 8 as shown in fig. 7, so that the semiconductor package 9 can be obtained. The encapsulating resin 8 is not particularly limited, and a known encapsulating resin that can be used for manufacturing a semiconductor package can be suitably used. The method of sealing with the sealing resin 8 is also not particularly limited, and a known method can be suitably used.

The semiconductor package of the present invention is formed by bonding a semiconductor chip to a wiring board or between semiconductor chips via a thermosetting body of an adhesive layer provided in the die-cut die-bonding film of the present invention.

As an example of the semiconductor package of the present invention, as shown in fig. 4 and 7, there is a semiconductor package 9 having a structure in which a semiconductor chip 4 and a wiring board 6 are bonded to each other through a thermosetting body of an adhesive layer included in a die-cut adhesive film of the present invention (the semiconductor package 9 of the embodiment of the present invention is packaged in fig. 7). As another example of the semiconductor package of the present invention, as shown in fig. 5 and 6, there is a semiconductor package 9 having a structure in which the semiconductor chips 4 are bonded to each other through a thermosetting body of the adhesive layer included in the die-cut die-bonding film of the present invention in addition to the bonding between the semiconductor chips 4 and the wiring board 6.

Further, by using the adhesive layer in the dicing die bond film of the present invention for bonding semiconductor chips in a multilayer stacked semiconductor chip, a semiconductor package having a structure in which semiconductor chips are bonded to each other by a thermosetting body of the adhesive layer included in the dicing die bond film of the present invention can be obtained. In this case, the semiconductor chip and the wiring board can be bonded to each other by a thermosetting body of the adhesive layer included in the die-cut die-bonding film of the present invention (for example, fig. 5 and 6), or can be bonded to each other by a generally used adhesive layer as a thermally conductive adhesive layer. Among them, it is preferable that the bonding is performed by a thermosetting body of the adhesive layer 2 included in the die-cut die-bonded crystal film of the present invention.

In the semiconductor package 9 having the structure shown in fig. 4 to 7, the adhesive layer 2 between the semiconductor chip 4 and the wiring board 6 and between the semiconductor chips 4 is present in a state of being thermally cured, that is, a thermally cured body as the adhesive layer is present in a state of bonding the respective members.

Examples

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples. Further, room temperature means 25 ℃ and MEK is methyl ethyl ketone and PET is polyethylene terephthalate.

(example 1)

[1. production of adhesive layer (dicing film) ]

(1) Production of substrate film

Mixing low density polyethylene (LDPE, density 0.92 g/cm)³The resin pellets having a melting point of 110 ℃ C. were melted at 230 ℃ and molded into a long film having a thickness of 70 μm by using an extruder. The obtained film was irradiated with 100kGy of electron beam to produce a substrate film.

(2) Production of adhesive layer

A copolymer having a weight average molecular weight of 80 ten thousand, which was composed of 50 mol% of butyl acrylate, 45 mol% of 2-hydroxyethyl acrylate and 5 mol% of methacrylic acid, was prepared. 2-isocyanatoethyl methacrylate was added in such a manner that the iodine value was 20, to prepare an acrylic copolymer having a glass transition temperature of-40 ℃, a hydroxyl value of 30mgKOH/g and an acid value of 5 mgKOH/g.

Next, 5 parts by mass of Coronate L (trade name, manufactured by Nippon Polyurethane) as a polyisocyanate and 3 parts by mass of Esacure KIP 150 (trade name, manufactured by Lamberti) as a photopolymerization initiator were added to 100 parts by mass of the acrylic copolymer prepared above, and the obtained mixture was dissolved in ethyl acetate and stirred to prepare an adhesive composition.

Next, the pressure-sensitive adhesive composition was applied to a release liner composed of a polyethylene terephthalate (PET) film subjected to a mold release treatment so that the thickness after drying was 20 μm, and dried at 110 ℃ for 3 minutes to form a pressure-sensitive adhesive layer, and then the substrate film prepared above was laminated to the pressure-sensitive adhesive layer to prepare a die-cut film in which the pressure-sensitive adhesive layer was formed on the substrate film.

[2. production of adhesive layer (Crystal-bonded film) ]

A resin varnish was obtained by heating and stirring 56 parts by mass of a triphenylmethane type Epoxy resin (trade name: EPPN-501H, weight average molecular weight: 1000, softening point: 55 ℃, semisolid, Epoxy equivalent: 167g/eq, manufactured by Nippon chemical Co., Ltd.), 49 parts by mass of a bisphenol A type Epoxy resin (trade name: YD-128, weight average molecular weight: 400, softening point: less than 25 ℃, liquid, Epoxy equivalent: 190g/eq, manufactured by Nippon chemical Epoxy Co., Ltd.), 30 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, room temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nippon chemical Epoxy Co., Ltd.) and 67 parts by mass of MEK for 2 hours at a temperature of 110 ℃ in a 1000ml separable flask.

Next, the resin varnish was transferred to a planetary mixer (800 ml), 205 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatech, Ltd., average particle diameter (d 50): 0.6 μm) was added, 8.5 parts by mass of an imidazole-type curing agent (trade name: 2PHZ-PW, manufactured by Kabushiki Kaisha) and 3.0 parts by mass of a silane coupling agent (trade name: Sila-Ace S-510, manufactured by JNC Co., Ltd.) were added, and the mixture was stirred and mixed at room temperature for 1 hour, followed by vacuum defoaming to obtain a mixed varnish.

Subsequently, the obtained mixed varnish was applied to a release-treated PET film (release film) having a thickness of 38 μm, and dried by heating at 130 ℃ for 10 minutes to produce a die bond film having an adhesive layer formed on the release film and having a length of 300mm, a width of 200mm, and a thickness of 10 μm. The thickness is a value measured by the above method.

[3. production of die-cut die-bonding film ]

Next, the dicing film is cut into a circular shape so as to cover the opening of the ring frame. In addition, the die attach film is cut into a circular shape that covers the back surface of the wafer.

The pressure-sensitive adhesive layer exposed by peeling the release liner from the cut crystalline film cut as described above was bonded to the adhesive layer of the crystalline adhesive film cut as described above using a roll press under a load of 0.4MPa and a speed of 1.0m/min, to produce a cut crystalline adhesive film. The dicing die-bonding film is larger than the die-bonding film, and has a portion where the adhesive layer is exposed around the adhesive layer.

(example 2)

A die-cut and die-bonded film was produced in the same manner as in example 1 except that 320 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatech, Ltd., average particle diameter (d 50): 0.6 μm) was used.

(example 3)

A die-cut and die-bonded film was produced in the same manner as in example 1 except that 480 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatech, Ltd., average particle diameter (d 50): 0.6 μm) was used.

(example 4)

A sliced crystal film was produced in the same manner as in example 1 except that 30 parts by mass of a bisphenol A/F copolymer type phenoxy resin (trade name: YP-70, weight average molecular weight: 55000, Tg: 72 ℃, room temperature (25 ℃) elastic modulus: 1400MPa, manufactured by Nikkiso Epoxy Co., Ltd.) was used instead of the bisphenol A type phenoxy resin.

(example 5)

A die-cut and die-bonded film was produced in the same manner as in example 1 except that 30 parts by mass of a low-elasticity and high-heat-resistance phenoxy resin (trade name: FX-310, weight-average molecular weight: 40000, Tg: 110 ℃, modulus of elasticity at room temperature (25 ℃) of 500MPa, manufactured by Nikkiso Epoxy Co., Ltd.) was used instead of the bisphenol A type phenoxy resin.

(example 6)

A crystal-cut and crystal-bonded film was produced in the same manner as in example 1 except that 44 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight-average molecular weight: 70000, Tg: 84 ℃, room-temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 350 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

(example 7)

A crystal-cut and crystal-bonded film was produced in the same manner as in example 1 except that 70 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, room temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 400 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

(example 8)

A sliced crystal film was produced in the same manner as in example 1 except that 50 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, elastic modulus at room temperature (25 ℃) 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 360 parts by mass of a silver filler (trade name: AG-4-8F, manufactured by Dowa electronics, Ltd., average particle diameter (d 50): 2.0 μm) were used.

(example 9)

A sliced crystal film was produced in the same manner as in example 1 except that 50 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, elastic modulus at room temperature (25 ℃) 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 610 parts by mass of a silver filler (trade name: AG-4-8F, manufactured by DOWA electronics Co., Ltd., average particle diameter (d 50): 2.0 μm) were used.

(example 10)

A crystal-cut and crystal-bonded film was produced in the same manner as in example 1 except that 50 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, room temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 950 parts by mass of a silver filler (trade name: AG-4-8F, manufactured by DOWA electronics, Ltd., average particle diameter (d 50): 2.0 μm) were used.

Comparative example 1

A crystal-cut and crystal-bonded film was produced in the same manner as in example 1 except that 10 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, room temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 280 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

Comparative example 2

A crystal-cut and crystal-bonded film was produced in the same manner as in example 1 except that 250 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, room temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 800 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

Comparative example 3

A crystal-cut and crystal-bonded film was produced in the same manner as in example 1 except that 250 parts by mass of a bisphenol A type phenoxy resin (trade name: YP-50, weight average molecular weight: 70000, Tg: 84 ℃, room temperature (25 ℃) elastic modulus: 1700MPa, manufactured by Nikkiso Epoxy Co., Ltd.) and 130 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

Comparative example 4

A die-cut crystal-bonded film was produced in the same manner as in example 1 except that 30 parts by mass of bisphenol F +1, 6-hexanediol diglycidyl ether type phenoxy resin (trade name: YX-7180, weight-average molecular weight: 50000, Tg: 15 ℃, modulus of elasticity at room temperature (25 ℃) of 200MPa, manufactured by Mitsubishi chemical corporation) and 320 parts by mass of alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

Comparative example 5

A die-cut film was produced in the same manner as in example 1 except that 120 parts by mass of an acrylic polymer solution (trade name: S-2060, weight average molecular weight: 500000, Tg: 23 ℃, modulus of elasticity at room temperature (25 ℃) of 50MPa, solid content: 25% (organic solvent: toluene), manufactured by Toyo chemical Co., Ltd.) (wherein the amount of the acrylic polymer itself to be mixed is 30 parts by mass), and 320 parts by mass of an alumina filler (trade name: AO-502, manufactured by Admatechs, Ltd., average particle diameter (d 50): 0.6 μm) were used.

For each of the sliced crystal-bonded films produced above, the elastic modulus before curing, melt viscosity, peeling force, crystal-bonding evaluation, thermal conductivity, and continuous pickup were measured by the following methods.

The obtained results are summarized in table 1 below together with the composition of the adhesive layer.

< measurement of elastic modulus and melt viscosity before curing >

A square having a length of 5.0cm × a width of 5.0cm was cut from the die-cut die-bonded film prepared as described above, the die-cut films (adhesive layer and base film) and the release film were peeled off, the cut samples were laminated, and the laminated layers were bonded to a hot plate at a stage 70 ℃ by a hand roller, to obtain a test piece of an adhesive layer having a thickness of about 1.0 mm.

The test piece was measured for the change in the viscous resistance at a temperature range of 20 to 250 ℃ and a temperature rise rate of 5 ℃/min using a rheometer (RS6000, manufactured by Haake). From the obtained temperature-viscosity resistance curves, the elastic modulus G' (kPa) before curing at 25 ℃ and 80 ℃ and the melt viscosity (Pa · s) at 120 ℃ were calculated, respectively.

< peeling force >

The sliced crystal-bonded film prepared as described above was irradiated with 200mJ/cm of ultraviolet light using an ultraviolet irradiation apparatus (trade name: RAD-2000F/8, manufactured by Lintec Co., Ltd.)²) The dicing film (adhesive layer) was irradiated with ultraviolet light from the side thereof, and the interlayer peel strength between the adhesive layer and the dicing film (adhesive layer and base film) was measured in a constant temperature bath at room temperature and 80 ℃.

The measurement conditions were as follows: peeling test at 180 ℃ in accordance with JIS Z0237

A measuring device: tensile tester (model TCR1L made by Shimadzu)

< evaluation of die-bonding >

The sliced crystal-bonded film prepared as described above was peeled off, and bonded to one surface of a dummy silicon wafer (8 inches in size and 100 μm in thickness) by a manual laminator (product name: FM-114, manufactured by Technvision) at a temperature of 70 ℃ and a pressure of 0.3 MPa. Next, a dicing apparatus (trade name: DFD-6340, manufactured by DISCO) equipped with a biaxial dicing blade (Z1: NBC-ZH2050(27HEDD), manufactured by DISCO Inc./Z2: NBC-ZH127F-SE (BC), manufactured by DISCO Inc.) was used to cut the wafer from the dummy silicon wafer side so as to form a square having a size of 10mm × 10mm, thereby obtaining a dummy chip with an adhesive layer.

Next, an ultraviolet irradiation apparatus (trade name: RAD-2000F/8, manufactured by Lintec Co., Ltd., irradiation dose 200 mJ/cm) was used²) The wafer was irradiated with ultraviolet light from the back side thereof, and the wafer was bonded with a tape bonder (trade name: DB-800 manufactured by Hitachi Hipposhu Co., Ltd.) was thermocompression bonded at 120 deg.C under a pressure of 0.1MPa (load of 400gf) for 1.0 second to obtain the tape adhesiveThe dummy chip of the layer was bonded to the mounting surface side of a lead frame substrate (42Arroy, manufactured by letterpress printing).

For the dummy chip with the adhesive layer thermocompression bonded to the substrate, the occurrence of voids at the interface between the adhesive layer and the lead frame substrate mounting surface was observed using an ultrasonic testing apparatus (SAT) (FS 300III, manufactured by Hitachi Power Solutions), and the crystal adhesion was evaluated based on the following evaluation criteria. In the present invention, the evaluation "B" or more is a pass.

Evaluation criteria-

A: no voids were observed in all of the 24 dummy chips mounted.

B: gaps are generated among 1-5 chips in 24 mounted dummy chips.

C: more than 6 chips out of the 24 mounted dummy chips create voids.

< thermal conductivity after Heat curing >

A square piece having a side of 50mm or more was cut from the die-cut die-bonded film prepared as described above, the die-cut film (adhesive layer and base film) and the release film were peeled off, and the cut sample was stacked to obtain an adhesive layer laminate having a thickness of 5mm or more.

The sample was placed on a disk-shaped mold having a diameter of 50mm and a thickness of 5mm, heated at 150 ℃ and a pressure of 2MPa for 10 minutes by a compression molding machine and taken out, and then further heated at 180 ℃ for 1 hour in a drier to thermally cure the adhesive layer, thereby obtaining a disk-shaped test piece having a diameter of 50mm and a thickness of 5 mm.

The test piece was measured for thermal conductivity (W/(m.K)) by a heat flow meter method (according to JIS-A1412) using a thermal conductivity measuring apparatus (trade name: HC-110, manufactured by Yinzhong Seiki K.K.).

< evaluation of continuous pickup >

The sliced crystal-bonded film prepared as described above was peeled off, and bonded to one surface of a dummy silicon wafer (8 inches in size and 100 μm in thickness) by a manual laminator (product name: FM-114, manufactured by Technvision) at a temperature of 70 ℃ and a pressure of 0.3 MPa. Next, a dicing apparatus (trade name: DFD-6340, manufactured by DISCO) equipped with a biaxial dicing blade (Z1: NBC-ZH2050(27HEDD), manufactured by DISCO Inc./Z2: NBC-ZH127F-SE (BC), manufactured by DISCO Inc.) was used to cut the wafer from the dummy silicon wafer side so as to form a square having a size of 5mm × 5mm, thereby obtaining a dummy chip with an adhesive layer.

Next, an ultraviolet irradiation apparatus (trade name: RAD-2000F/8, manufactured by Lintec Co., Ltd., irradiation dose 200 mJ/cm) was used²) The wafer was irradiated with ultraviolet light from the back side thereof, and the wafer was bonded with a tape bonder (trade name: DB-800, manufactured by hitachi heigh and heigh technologies) the dummy chip with the adhesive layer was picked up from the dicing film (adhesive layer and base film) under conditions of 120 ℃, a pressure of 0.1MPa (load of 400gf), and a time of 1.0 second, and thermocompression bonded to the mounting surface side of the lead frame substrate (manufactured by 42Arroy, typographic co). This picking-up and thermocompression bonding process was continuously repeated, and the continuous picking-up property was evaluated based on the following evaluation criteria. In the present invention, the evaluation "B" or more is a pass.

Evaluation criteria-

A: in 96 dummy chips which were successively picked up and thermocompression bonded, no defects such as pickup failure or adhesive layer residue on the dicing film were observed.

B: among 96 dummy chips successively picked up and thermocompression bonded, 1 to 10 chips having defects such as picking-up errors and adhesive layer residues on dicing films occurred.

C: among 96 dummy chips successively subjected to picking up and thermocompression bonding, 11 or more chips were subjected to picking up failure, adhesive layer residue on dicing film, and other defects.

< measurement of average particle diameter (d50) >

0.1g of each of the inorganic fillers and MEK9.9g used above were weighed, and the mixture thereof was subjected to ultrasonic dispersion treatment for 5 minutes to prepare a sample for measurement. The average particle diameter (d50) of the measurement sample was determined from a cumulative curve of volume fractions of particle diameters in a particle size distribution measured by a laser diffraction/scattering method (model: LMS-2000e, manufactured by SEISHIN ENTERPRISE Co., Ltd.).

< Normal temperature (25 ℃ C.) elastic modulus of phenoxy resin >

In a 500ml separable flask, 30 parts by mass of each phenoxy resin and 70 parts by mass of MEK (methyl ethyl ketone) were heated and stirred at a temperature of 110 ℃ for 2 hours to obtain resin varnishes.

Then, this resin varnish was applied to a PET film (release film) having a thickness of 38 μm and subjected to mold release treatment, and the film was dried by heating at 130 ℃ for 10 minutes to obtain a phenoxy resin film having a length of 300mm, a width of 200mm and a thickness of 100 μm.

The phenoxy resin film was cut into a size of 5mm × 17mm, and the measurement was performed using a dynamic viscoelasticity measuring apparatus (trade name: Rheogel-E4000F, manufactured by UBM Co., Ltd.) under conditions of a measurement temperature range of 0 to 100 ℃, a temperature rise rate of 5 ℃/min, and a frequency of 1Hz, to obtain a value of the elastic modulus at 25 ℃.

The acrylic resin used in comparative example 5 was also measured for its elastic modulus at 25 ℃ by the above method, in the same manner as for the phenoxy resin.

< glass transition temperature (Tg) of phenoxy resin >

The phenoxy resin film produced by the method described in the measurement of the modulus of elasticity was measured using a differential scanning calorimeter (model: DSC7000, manufactured by Hitachi High-Tech Science) under a temperature rise rate of 5 ℃/min, and the temperature at which the base line shifts to the endothermic peak side was measured as the glass transition temperature (Tg).

< weight average molecular weight >

For each phenoxy resin, gel permeation chromatography (model: HLC-8320, manufactured by Tosoh corporation) was used, and measurement was performed at a flow rate of 1ml/min and a column chamber temperature of 40 ℃ using tetrahydrofuran as an eluent. The weight average molecular weight was calculated using a standard polystyrene calibration curve.

The acrylic resin used in comparative example 5 was also determined for its elastic modulus at 25 ℃, glass transition temperature, and weight average molecular weight by the above-described methods, similarly to the phenoxy resin.

< notes on the tables >

The "-" in the column of the adhesive layer means that the component is not contained.

The following is evident from table 1.

In the die-cut crystal-bonded film of comparative example 1, the ratio of the phenoxy resin (C) to the total content of the epoxy resin (a) and the phenoxy resin (C) was less than 10% by mass, and the peel force between the adhesive layer and the pressure-sensitive adhesive layer at 80 ℃ was more than 0.40N/25 mm. In the die-cut die-bonding film of comparative example 1, when the pickup collet is used to store heat, a pickup failure occurs in 11 or more chips out of 96 chips, and the pickup performance is poor.

In the die-cut crystal-bonded films of comparative examples 2 and 3, the ratio of the phenoxy resin (C) to the total content of the epoxy resin (a) and the phenoxy resin (C) was more than 60% by mass. In the die-cut die-bond film of comparative examples 2 and 3, voids were generated in 6 or more of the 24 chips when they were thermocompression bonded to the wiring board, and the generation of voids was not sufficiently suppressed. In the case of the die-cut die-bonding film of comparative example 3, the thermal conductivity of the adhesive layer after heat curing was as low as less than 1.0W/m · K, and the heat dissipation as an adhesive for semiconductor encapsulation was also insufficient.

In the die-cut crystal-bonded film of comparative example 4, the modulus of elasticity at 25 ℃ of the phenoxy resin (C) was less than 500 MPa. Further, the die bond film of comparative example 5 contains not a phenoxy resin but an acrylic resin (elastic modulus at 25 ℃ is less than 500 MPa). In the die-cut crystal-bonded films of comparative examples 4 and 5, when the pickup collet is used to store heat, a pickup failure occurred in 11 or more chips out of 96 chips, and the pickup performance was poor.

In contrast, the sliced crystalline and crystalline films according to examples 1 to 10 of the present invention are excellent in continuous pickup performance in semiconductor processing, and are less likely to cause pickup failure even if the collet chuck is used for heat accumulation. In addition, the occurrence of voids when thermocompression bonded to a wiring board is also suppressed.

The present application claims priority to Japanese patent application No. 2020-044660, which was filed in Japan on 3/13/2020, which is hereby incorporated by reference and the contents of which are incorporated as part of the description of the present specification.

Description of the symbols

1 semiconductor wafer

2 adhesive layer

3 adhesive layer

4 semiconductor chip

5 semiconductor chip with film adhesive

6 wiring board

7 bonding wire

8 encapsulating resin

And 9, packaging the semiconductor.