阅读说明：本技术 密封用片、带隔片的密封用片、半导体装置、及半导体装置的制造方法 (Sealing sheet, sealing sheet with spacer, semiconductor device, and method for manufacturing semiconductor device ) 是由 饭野智绘 志贺豪士 石井淳 于 2015-08-06 设计创作，主要内容包括：本发明提供能够防止在搬送时等从吸附夹头上落下、并且能够将半导体芯片适当地埋入的密封用片。一种密封用片,其中,厚度t[mm]与50℃下的储存弹性模量G’[Pa]之积α满足300≤α≤1.5×10<Sup>5</Sup>。(The invention provides a sealing sheet which can prevent a semiconductor chip from falling off from an adsorption chuck during transportation and the like and can appropriately embed the semiconductor chip. A sealing sheet, wherein the thickness t [ mm ]]And storage elastic modulus G' Pa at 50 deg.C]The product alpha of which is 300-1.5 x 10 5 。)

1. A sealing sheet characterized in that the product alpha of the thickness t and the storage elastic modulus G 'at 50 ℃ satisfies the following formula 1, wherein the unit of the thickness t is mm, the unit of the storage elastic modulus G' is Pa,

formula 1: alpha is more than or equal to 300 and less than or equal to 1.5 multiplied by 10⁵,

The storage elastic modulus G' is 400Pa or more and 180000Pa or less.

2. A sealing sheet with a separator, comprising the sealing sheet according to claim 1 and a separator laminated on at least one surface of the sealing sheet,

the product beta of the bending elastic modulus E at 25 ℃ and the area A of the sealing sheet satisfies the following formula 2, wherein the unit of the bending elastic modulus E is N/mm²The unit of area A is mm²，

Formula 2: 4.0X 10⁶≤β≤1.7×10⁹。

3. A semiconductor device manufactured by using the sealing sheet according to claim 1.

4. A semiconductor device manufactured by using the sealing sheet with a separator according to claim 2.

5. The sealing sheet according to claim 1, wherein the area A of the sealing sheet is 40000mm²The above.

6. The separator-equipped sealing sheet according to claim 2, wherein the area A of the sealing sheet is 40000mm²The above.

7. A method for manufacturing a semiconductor device, comprising the steps of:

a step A of preparing a laminate in which a semiconductor chip is fixed to a support;

a step B of preparing a sealing sheet with a separator according to claim 2;

a step C of disposing the sealing sheet with a separator on the semiconductor chip of the laminate; and

and a step D of embedding the semiconductor chip in the sealing sheet to form a sealing body in which the semiconductor chip is embedded in the sealing sheet.

Technical Field

The present invention relates to a sealing sheet, a sealing sheet with a spacer, a semiconductor device, and a method for manufacturing a semiconductor device.

Background

Conventionally, a method of manufacturing a semiconductor device is known in which a sealing sheet is disposed on 1 or more semiconductor chips fixed to a substrate or the like, and then the semiconductor chips are embedded in the sealing sheet by applying pressure under heating (for example, see patent document 1).

Disclosure of Invention

Problems to be solved by the invention

When the sealing sheet as described above is used, it may be lifted and transported by an adsorption chuck. However, the sealing sheet may fall from the suction chuck at the time of lifting, transportation, or the like. On the other hand, if the sealing sheet is too hard, there is a problem that the semiconductor chip cannot be embedded properly.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a sealing sheet and a sealing sheet with a spacer, which can prevent a semiconductor chip from falling off from an adsorption chuck during transportation or the like and can appropriately embed the semiconductor chip. Also provided are a sealing sheet and a semiconductor device manufactured using the sealing sheet with a separator. Also disclosed is a method for producing a semiconductor device using such a sealing sheet with a separator.

Means for solving the problems

The present inventors have conducted intensive studies on the above problems. As a result, the present inventors have found that, when the product of the thickness of the sealing sheet and the storage elastic modulus G' is within a certain range, the sealing sheet can be prevented from falling off from the suction chuck during transportation or the like, and the semiconductor chip can be appropriately embedded in the sealing sheet, thereby completing the present invention.

That is, the sealing sheet according to the present invention is characterized in that,

the product alpha of the thickness t [ mm ] and the storage elastic modulus G' [ Pa ] at 50 ℃ satisfies the following formula 1.

Formula 1: alpha is more than or equal to 300 and less than or equal to 1.5 multiplied by 10⁵

First, the thinner the thickness, the easier the deflection, and the thicker the thickness, the harder the deflection. The storage modulus is softer and more flexible as the value is smaller, while being harder and less flexible as the value is larger. Therefore, when the sealing sheet is thin, the storage elastic modulus is not necessarily increased, and the sealing sheet is deformed. On the other hand, when the sealing sheet is thick, the sealing sheet does not deflect even if the storage elastic modulus is not so large. The present inventors have found that: as described above, the thickness and storage modulus of elasticity of the sealing sheet are closely related to the deflection. Furthermore, the present inventors have found that: when the product α of the thickness and the storage elastic modulus is set to 300 or more, the sealing sheet can be prevented from being deflected and falling down during transportation or the like.

If the storage elastic modulus is too high, although flexure can be suppressed, the semiconductor chip cannot be embedded. Thus, the present inventors have found that: in general, the thickness of the sealing sheet is considered to be 1.5X 10, and the product α of the thickness and the storage elastic modulus is set to⁵Hereinafter, the semiconductor chip can be embedded in the sealing sheet as appropriate.

As described above, according to the sealing sheet of the present invention, since the product α of the thickness t [ mm ] and the storage elastic modulus G' [ Pa ] at 50 ℃ is within the range satisfying the above formula 1, the sealing sheet can be prevented from falling off from the suction chuck during transportation or the like, and the semiconductor chip can be appropriately embedded in the sealing sheet.

The measurement temperature of the storage elastic modulus G' is not the temperature at the time of transportation, that is, room temperature (25 ℃), but is set to 50 ℃ because the measurement error becomes large at 25 ℃, and therefore, a temperature close to room temperature with a small measurement error is used.

The sealing sheet with a separator according to the present invention is characterized in that,

comprising the sealing sheet and a separator laminated on at least one surface of the sealing sheet,

flexural modulus of elasticity E [ N/mm at 25 DEG C²]The area A [ mm ] of the sealing sheet²]The product β satisfies the following formula 2.

Formula 2: 4.0X 10⁶≤β≤1.7×10⁹

As for the area, the larger the area, the easier the flexure, and the smaller the area, the harder the flexure. The flexural modulus is softer and more flexible as the value is smaller, while being harder and more difficult to flex as the value is larger. Therefore, when the sealing sheet has a large area, the sealing sheet will be bent if the bending elastic modulus is not necessarily increased to a large extent. On the other hand, when the sealing sheet has a small area, the sealing sheet is not bent even if the bending elastic modulus is not so large. And, if the product beta of the thickness and the flexural modulus is set to 4.0 x 10⁶As described above, the sealing sheet can be prevented from being bent and falling down during transportation or the like. In addition, when the area is large, the flexural modulus must be increased to some extent, but when the flexural modulus exceeds an appropriate range, the embeddability becomes problematic. Thus, by setting the range of β to 1.7 × 10⁹Hereinafter, the semiconductor chip can be embedded in the sealing sheet without deforming or bending the resin sheet.

The semiconductor device according to the present invention is manufactured using the sealing sheet.

Since the sealing sheet satisfies the above formula 1, it is possible to prevent the sealing sheet from falling off from the suction chuck during transportation or the like. Further, since the sealing sheet is used, the semiconductor chip is appropriately embedded in the sealing sheet. Therefore, the yield of the manufactured semiconductor device is improved.

The semiconductor device according to the present invention is manufactured using the sealing sheet with a separator.

Since the sealing sheet with the spacer satisfies the above formula 1, it is possible to prevent the sealing sheet from falling off from the suction chuck during transportation or the like. Further, since the sealing sheet with the spacer is used, the semiconductor chip is appropriately embedded in the sealing sheet. Therefore, the yield of the manufactured semiconductor device is improved.

In the above constitution, the sealing sheet preferably has an area A of 40000mm²The above.

In the above configuration, the sealing sheet with a separator preferably has an area A of 40000mm²The above.

Since the sealing sheet satisfies the formula 1, the sheet can be prevented from being bent. Therefore, even if the area A of the sealing sheet is set to 40000mm²Such a large area can also prevent the suction chuck from falling off during transportation or the like.

The method for manufacturing a semiconductor device according to the present invention includes the steps of:

a step A of preparing a laminate in which a semiconductor chip is fixed to a support;

a step (B) of preparing the sealing sheet with a separator;

a step C of disposing the sealing sheet with the spacer on the semiconductor chip of the laminate;

and a step D of embedding the semiconductor chip in the sealing sheet to form a sealed body in which the semiconductor chip is embedded in the sealing sheet.

According to the above configuration, since the sealing sheet satisfies the above formula 1, it is possible to suppress the sealing sheet from falling off from the suction chuck during transportation or the like. Therefore, the yield of semiconductor devices manufactured using the sealing sheet with a spacer can be improved.

Effects of the invention

According to the present invention, it is possible to provide a sealing sheet and a sealing sheet with a spacer, which can prevent a semiconductor chip from falling off from an adsorption chuck during transportation or the like and can appropriately embed the semiconductor chip. Further, the sealing sheet and a semiconductor device manufactured using the sealing sheet with a separator can be provided. Further, a method for manufacturing a semiconductor device using the sealing sheet with a separator can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view of a sealing sheet with a separator on both sides according to the present embodiment.

Fig. 2 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 3 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 4 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 5 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 6 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 7 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 8 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 9 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Fig. 10 is a schematic cross-sectional view for explaining a method for manufacturing a semiconductor device according to this embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments.

(sealing sheet with spacer)

Fig. 1 is a schematic cross-sectional view of a sealing sheet with a separator according to the present embodiment. As shown in fig. 1, the separator-equipped sealing sheet 10 includes a sealing sheet 40, a separator sheet 41a laminated on one surface of the sealing sheet 40, and a separator sheet 41b laminated on the other surface of the sealing sheet 40. The spacer 41a and the spacer 41b correspond to the spacer of the present invention.

In the present embodiment, the case where the separator is laminated on both surfaces of the sealing sheet, that is, the sealing sheet with separators on both surfaces, is described, but the sealing sheet with separators of the present invention is not limited to this example, and may be a sealing sheet with separators on only one surface, that is, a sealing sheet with separators on one surface.

In the present embodiment, a sealing sheet with a separator is described, but the present invention may be a single sealing sheet without a separator laminated thereon. As the sealing sheet having no laminated separator, for example, a form in which the separator 41a and the separator 41b are not laminated (a single body of the sealing sheet 40) in the sealing sheet 10 with a separator can be cited.

(sealing sheet)

The product alpha of the thickness t [ mm ] of the sealing sheet 40 and the storage elastic modulus G' [ Pa ] at 50 ℃ satisfies the following formula 1.

Formula 1: alpha is more than or equal to 300 and less than or equal to 1.5 multiplied by 10⁵

The lower limit of the product α is preferably 400, and more preferably 500. The upper limit of the product α is preferably 1.4 × 10⁵More preferably 1.3X 10⁵. Since the product α is within a range satisfying the above formula 1, the semiconductor chip can be appropriately embedded in the sealing sheet while suppressing the sealing sheet from falling off from the suction chuck during transportation or the like.

The thickness t of the sealing sheet 40 is preferably 0.05mm or more and 1.3mm or less, and more preferably 0.1mm or more and 1.0mm or less. By setting the thickness t to 0.05mm or more, the semiconductor chip can be embedded appropriately. On the other hand, by setting the thickness t to 1.3mm or less, the thickness of the manufactured semiconductor device can be reduced.

The thickness of the sealing sheet is an average value of the thicknesses measured at 25 points at random.

The storage elastic modulus G' of the sealing sheet 40 is preferably 400Pa to 180000Pa, more preferably 600Pa to 170000 Pa. By setting the storage elastic modulus G' to 400Pa or more, the resin flow can be suppressed, and the thickness control at the time of embedding the semiconductor chip can be made good. On the other hand, by setting the storage elastic modulus G' to 180000Pa or less, the semiconductor chip can be embedded satisfactorily.

The storage elastic modulus G' is a storage elastic modulus after molding the sealing sheet and before heat curing. The method for measuring the storage elastic modulus G' is based on the method described in examples. The storage elastic modulus G' Pa can be controlled by changing the composition of the sealing sheet 40 by changing the filling amount, particle diameter, and the like of the inorganic filler (filler).

The product γ of the thickness t [ mm ] of the sealing sheet 40 before heat curing and the storage elastic modulus E' [ Pa ] at 25 ℃ after heat curing is preferably 1200000 or more, and more preferably 1500000 or more. The thinner the thickness, the less resistant to external impact, and the thicker the thickness, the more resistant to external impact. In addition, the storage elastic modulus after heat curing is softer and less resistant to an external impact as the value is smaller, and is harder and more resistant to an external impact as the value is larger. Therefore, when the sealing sheet is thin, the semiconductor chip can be appropriately protected from external impact or the like even if the storage elastic modulus after thermosetting is small to some extent. On the other hand, when the sealing sheet is thin, if the storage elastic modulus after thermosetting is not necessarily increased to a large extent, the semiconductor chip cannot be appropriately protected from external impact or the like. The present inventors have found that: as described above, the thickness of the sealing sheet and the storage elastic modulus after heat curing are closely related to the protection property of the semiconductor chip after sealing. Furthermore, the present inventors have found that: when the product γ is set to 1200000 or more, the sealing sheet 40 after heat curing has good hardness, and as a result, the semiconductor chip can be appropriately protected from external impact or the like.

As described above, when the product γ is set to 1200000 or more, the semiconductor chip can be appropriately protected from external impact or the like.

The area A of the sealing sheet 40 in plan view is preferably 40000mm²The above. More preferably 70650mm²Above, 90000mm is more preferable²The above. Since the sealing sheet 40 satisfies the above formula 1, the deflection can be suppressed. Therefore, even if the area A of the sealing sheet 40 is set to 40000mm²Such a large area can also prevent the suction chuck from falling off during transportation or the like. Further, if the film can be used over a large area, the film is excellent in terms of improvement in production efficiency. The larger the area a is, the more preferable it is, but 562500mm is, for example, because it is difficult to drop the suction chuck from the suction chuck during transportation or the like²Preferably 500000mm²The following.

The shape of the sealing sheet 40 in a plan view is not particularly limited, and may be rectangular or circular. Among them, a rectangle in which the length of each side is 200mm or more and the length of each side is 750mm or less is preferable. When the length of all the sides is 200mm, the area A is 40000mm²When the length of all the sides is 750mm, the area A is 562500mm²。

The material constituting the sealing sheet 40 preferably contains an epoxy resin and a phenol resin as a curing agent. Thus, a good thermosetting property can be obtained.

The epoxy resin is not particularly limited. For example, various epoxy resins such as triphenylmethane type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, modified bisphenol a type epoxy resin, bisphenol F type epoxy resin, modified bisphenol F type epoxy resin, dicyclopentadiene type epoxy resin, novolac type epoxy resin, phenoxy resin, and the like can be used. These epoxy resins may be used alone, or 2 or more kinds may be used in combination.

From the viewpoint of ensuring the toughness of the epoxy resin after curing and the reactivity of the epoxy resin, an epoxy resin which is solid at normal temperature and has an epoxy equivalent of 150 to 250 and a softening point or melting point of 50 to 130 ℃ is preferred, and among them, from the viewpoint of reliability, a triphenylmethane type epoxy resin, a cresol novolac type epoxy resin, and a biphenyl type epoxy resin are more preferred.

The phenolic resin is not particularly limited as long as it is a resin that undergoes a curing reaction with an epoxy resin. For example, a phenol novolac resin, a phenol aralkyl resin, a biphenyl aralkyl resin, a dicyclopentadiene type phenol resin, a cresol novolac resin, a resol type phenol resin, or the like is used. These phenol resins may be used alone, or 2 or more of them may be used in combination.

The phenolic resin is preferably a phenolic resin having a hydroxyl equivalent of 70 to 250 and a softening point of 50 to 110 ℃ from the viewpoint of reactivity with an epoxy resin, and among these, a phenol novolac resin is preferably used from the viewpoint of high curing reactivity. In addition, from the viewpoint of reliability, a phenol resin having low moisture absorption such as a phenol aralkyl resin or a biphenyl aralkyl resin may be suitably used.

The mixing ratio of the epoxy resin and the phenol resin is preferably 0.7 to 1.5 equivalents, more preferably 0.9 to 1.2 equivalents, of the total of hydroxyl groups in the phenol resin to 1 equivalent of the epoxy groups in the epoxy resin, from the viewpoint of curing reactivity.

The total content of the epoxy resin and the phenol resin in the sealing sheet 40 is preferably 2.5 wt% or more, and more preferably 3.0 wt% or more. When the content is 2.5 wt% or more, the adhesive strength to the semiconductor chip 23, the semiconductor wafer 22, or the like can be favorably obtained. The total content of the epoxy resin and the phenol resin in the sealing sheet 40 is preferably 20 wt% or less, and more preferably 10 wt% or less. When the content is 20% by weight or less, the moisture absorption property can be reduced.

The sealing sheet 40 may contain a thermoplastic resin. This makes it possible to obtain handling properties when uncured and low stress properties of a cured product.

Examples of the thermoplastic resin include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, a polybutadiene resin, a polycarbonate resin, a thermoplastic polyimide resin, a polyamide resin such as 6-nylon or 6, 6-nylon, a phenoxy resin, an acrylic resin, a saturated polyester resin such as PET or PBT, a polyamideimide resin, a fluororesin, a styrene-isobutylene-styrene block copolymer, and the like. These thermoplastic resins may be used alone or in combination of 2 or more. Among them, a styrene-isobutylene-styrene block copolymer is preferable from the viewpoint of low stress property and low water absorption property.

The content of the thermoplastic resin in the sealing sheet 40 is preferably set to 1.5 wt% or more and 2.0 wt% or more. When the content is 1.5% by weight or more, flexibility and flexibility can be obtained. The content of the thermoplastic resin in the sealing sheet 40 is preferably 6 wt% or less, and more preferably 4 wt% or less. When the content is 4 wt% or less, the adhesiveness to the semiconductor chip 23 or the semiconductor wafer 22 is good.

The sealing sheet 40 preferably contains an inorganic filler.

The inorganic filler is not particularly limited, and various fillers known in the art can be used, and examples thereof include powders of quartz glass, talc, silica (fused silica, crystalline silica, or the like), alumina, aluminum nitride, silicon nitride, and boron nitride. These can be used alone, or more than 2 kinds can be used in combination. Among these, silica and alumina are preferable, and silica is more preferable, because the linear expansion coefficient can be reduced favorably.

The silica is preferably a silica powder, and more preferably a fused silica powder. Examples of the fused silica powder include spherical fused silica powder and crushed fused silica powder, but spherical fused silica powder is preferable from the viewpoint of fluidity. Among them, the powder having an average particle diameter of preferably 10 to 30 μm, more preferably 15 to 25 μm is preferable.

The average particle size can be derived by, for example, using a sample arbitrarily extracted from the mother aggregate and measuring the average particle size by using a laser diffraction scattering particle size distribution measuring apparatus.

The content of the inorganic filler in the sealing sheet 40 is preferably 75 to 95 wt%, more preferably 78 to 95 wt%, based on the entire sealing sheet 40. When the content of the inorganic filler is 75 wt% or more based on the entire sealing sheet 40, the thermal expansion coefficient is low, and mechanical failure due to thermal shock can be suppressed. On the other hand, if the content of the inorganic filler is 95 wt% or less with respect to the entire sealing sheet 40, flexibility, fluidity, and adhesiveness become more favorable.

The sealing sheet 40 preferably contains a curing accelerator.

The curing accelerator is not particularly limited as long as it cures the epoxy resin and the phenol resin, and examples thereof include organic phosphorus compounds such as triphenylphosphine and tetraphenylphosphonium tetraphenylboronate; imidazole compounds such as 2-phenyl-4, 5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Among them, 2-phenyl-4, 5-dihydroxymethylimidazole is preferable because the curing reaction does not progress rapidly even if the temperature is increased during kneading, and the sealing sheet 40 can be produced satisfactorily.

The content of the curing accelerator is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the total of the epoxy resin and the phenol resin.

The sealing sheet 40 preferably contains a flame retardant component. This can reduce the expansion of combustion when the member is ignited by short circuit, heat generation, or the like. Examples of the flame retardant component include various metal hydroxides such as aluminum hydroxide, magnesium hydroxide, iron hydroxide, calcium hydroxide, tin hydroxide, and composite metal hydroxide; phosphazene flame retardants, and the like.

The content of the phosphorus element contained in the phosphazene flame retardant is preferably 12 wt% or more from the viewpoint of exhibiting a flame retardant effect even in a small amount.

The content of the flame retardant component in the sealing sheet 40 is preferably 10% by weight or more, and more preferably 15% by weight or more, of the total organic components (excluding the inorganic filler). When the content is 10% by weight or more, good flame retardancy can be obtained. The content of the thermoplastic resin in the sealing sheet 40 is preferably 30 wt% or less, and more preferably 25 wt% or less. When the amount is 30% by weight or less, the deterioration of physical properties of the cured product (specifically, the deterioration of physical properties such as glass transition temperature and high-temperature resin strength) tends to be small.

The sealing sheet 40 preferably contains a silane coupling agent. The silane coupling agent is not particularly limited, and examples thereof include 3-glycidoxypropyltrimethoxysilane and the like.

The content of the silane coupling agent in the sealing sheet 40 is preferably 0.1 to 3 wt%. When the amount is 0.1% by weight or more, the strength of the cured product can be sufficiently obtained, and the water absorption can be reduced. If the amount is 3% by weight or less, the amount of exhaust gas can be reduced.

The sealing sheet 40 is preferably colored. Thus, a semiconductor device having excellent marking properties and appearance and having a valuable appearance can be produced. The colored sealing sheet 40 has excellent marking properties, and therefore can be marked to provide various information such as character information and graphic information. In particular, by controlling the color of the coloring, information (character information, graphic information, and the like) provided by the mark can be visually recognized with excellent visibility. Further, the sealing sheet 40 may be color-divided according to the product. When the sealing sheet 40 is colored (not colorless or transparent), the color to be expressed by the coloring is not particularly limited, and is preferably a dark color such as black, blue, or red, and is particularly preferably black.

When the sealing sheet 40 is colored, a color material (colorant) may be used depending on the target color. As such a color material, various kinds of dense color materials such as a black color material, a blue color material, and a red color material can be suitably used, and a black color material is particularly suitable. The coloring material may be any of a pigment, a dye, and the like. The color materials can be used alone or in combination of 2 or more. The dye may be any form of dye such as an acid dye, a reactive dye, a direct dye, a disperse dye, and a cationic dye. The form of the pigment is not particularly limited, and may be appropriately selected from known pigments.

In addition, other additives may be appropriately added to the sealing sheet 40 as needed, in addition to the above-described components.

The method for producing the sealing sheet 40 is not particularly limited, but a method of preparing a kneaded product of the resin composition for forming the sealing sheet 40 and coating the obtained kneaded product, and a method of plastic-processing the obtained kneaded product into a sheet shape are preferable. Thus, the sealing sheet 40 can be produced without using a solvent, and therefore, the semiconductor chip 23 can be prevented from being affected by the solvent that has volatilized.

Specifically, each component described later is melt-kneaded by a known kneading machine such as a mixing roll, a pressure kneader, or an extruder to prepare a kneaded product, and the obtained kneaded product is formed into a sheet by coating or plastic processing. The temperature is preferably not lower than the softening point of each component described above, for example, 30 to 150 ℃ as the kneading conditions, and is preferably 40 to 140 ℃ in view of thermosetting of the epoxy resin, and more preferably 60 to 120 ℃. The time is, for example, 1 to 30 minutes, preferably 5 to 15 minutes.

The kneading is preferably carried out under reduced pressure (under a reduced pressure atmosphere). This can deaerate and prevent the gas from entering the kneaded material. The pressure under reduced pressure is preferably 0.1kg/cm²Below, more preferably 0.05kg/cm²The following. The lower limit of the pressure under reduced pressure is not particularly limited, and is, for example, 1X 10^-4kg/cm²The above.

In the case of forming the sealing sheet 40 by coating the kneaded material, the kneaded material after melt-kneading is preferably coated without cooling while maintaining a high-temperature state. The coating method is not particularly limited, and examples thereof include a bar coating method, a doctor blade coating method, a slit die coating method, and the like. The temperature at the time of coating is preferably not lower than the softening point of each component described above, and is, for example, 40 to 150 ℃, preferably 50 to 140 ℃, and more preferably 70 to 120 ℃ in consideration of thermosetting property and moldability of the epoxy resin.

In the case where the kneaded material is subjected to plastic working to form the sealing sheet 40, the kneaded material after melt-kneading is preferably subjected to plastic working while being kept at a high temperature without being cooled. The plastic working method is not particularly limited, and a flat plate press method, a T-die extrusion method, a screw die extrusion method, a roll rolling method, a roll kneading method, a blow extrusion method, a co-extrusion method, a calender molding method, and the like can be mentioned. The plastic working temperature is preferably not lower than the softening point of each component described above, and is, for example, 40 to 150 ℃, preferably 50 to 140 ℃, and more preferably 70 to 120 ℃ in consideration of thermosetting property and moldability of the epoxy resin.

The sealing sheet 40 can also be obtained as follows: the sealing sheet 40 is obtained by dissolving a resin or the like for forming the sealing sheet in an appropriate solvent, dispersing the solution to prepare a varnish, and coating the varnish.

In the sealing sheet 10 with spacers on both sides, the bending elastic modulus E [ N/mm ] at 25 ℃ of the sealing sheet 10 with spacers on both sides²]The area A [ mm ] of the sealing sheet 40²]The product β preferably satisfies the following formula 2.

Formula 2: 4.0X 10⁶≤β≤1.7×10⁹

The lower limit of the product β is preferably 1.0 × 10⁷More preferably 5.0X 10⁷. The upper limit of the product β is preferably 1.5 × 10⁹More preferably 1.0X 10⁹. When the product β is within a range satisfying the above formula 2, the bending of the sealing sheet 10 with a spacer on both sides can be suppressed, and the embedding property of the resin into the semiconductor chip can be improved.

The sealing sheet 10 with spacers on both sides preferably has a flexural modulus E at 25 ℃ of 100N/mm²Above 3000N/mm²Hereinafter, more preferably 200N/mm²Above and 500N/mm²The following. By setting the flexural modulus E to 100N/mm²As described above, the flow of the resin is suppressed, and the thickness control at the time of embedding the semiconductor chip is improved. On the other hand, the flexural modulus E is set to 3000N/mm²The semiconductor chip can be embedded satisfactorily as follows.

The flexural elastic modulus E is a flexural elastic modulus after molding the sealing sheet and before thermosetting. The method for measuring the flexural modulus is based on the method described in examples. The flexural elastic modulus E [ Pa ] can be controlled by changing the composition of the sealing sheet 40 by changing the filling amount, particle diameter, and the like of the inorganic filler (filler).

(spacer)

The separator 41a and the separator 41b are preferably selected so as to be integrated with the sealing sheet 40 and so that the product β of the sealing sheet 10 with a separator satisfies the above formula 2. In particular, it is preferable to select the elastic modulus E at 25 ℃ of the sealing sheet 10 with a separator so as to be in the above numerical range, in such a manner as to be integrated with the sealing sheet 40.

In the present embodiment, a case will be described where the separator-equipped sealing sheet 10 of the present invention is a sealing sheet with separators on both sides. Therefore, the "flexural elastic modulus E at 25 ℃ of the sealing sheet with a separator" of the present invention is described as the flexural elastic modulus corresponding to the flexural elastic modulus at 25 ℃ of the entire sealing sheet with a separator 10 integrated with the separator 41a, the separator 41b, and the sealing sheet 40. However, when the sealing sheet with a separator of the present invention is a sealing sheet with a separator on one side, the "flexural elastic modulus E at 25 ℃ of the sealing sheet with a separator of the present invention" corresponds to the flexural elastic modulus at 25 ℃ of the entire sealing sheet with a separator on one side of the sealing sheet and the entire sealing sheet with a separator on one side of the sealing sheet.

Specific materials constituting the separator 41a and the separator 41b include, for example, paper-based substrates such as paper; fibrous base materials such as cloth, nonwoven fabric, felt, and net; metal base materials such as metal foil and metal plate; plastic base materials such as plastic sheets; a rubber-based base material such as a rubber sheet; a foam such as a foamed sheet, or a laminate thereof [ particularly, a laminate of a plastic base material and another base material, a laminate of plastic sheets, etc. ], or other suitable thin paper body. In the present invention, a plastic base material can be suitably used. Examples of the material of the plastic base include olefin resins such as Polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; copolymers containing ethylene as a monomer component, such as ethylene-vinyl acetate copolymers (EVA), ionomer resins, ethylene- (meth) acrylic acid copolymers, and ethylene- (meth) acrylate (random, alternating) copolymers; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); an acrylic resin; polyvinyl chloride (PVC); a polyurethane; a polycarbonate; polyphenylene Sulfide (PPS); amide resins such as polyamide (nylon) and wholly aromatic polyamide (aromatic polyamide); polyetheretherketone (PEEK); a polyimide; a polyetherimide; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymer); a cellulose-based resin; a silicone resin; fluorine resins, and the like. The separator 41a may be a single layer or a multilayer of 2 or more. The spacer 41a can be formed by a conventionally known method.

The separator 41a and the separator 41b may be subjected to a peeling treatment or may not be subjected to a mold release treatment.

Examples of the release agent used in the release treatment include fluorine-based release agents, long-chain alkyl acrylate-based release agents, and silicone-based release agents. Among them, silicone-based release agents are preferable.

The thickness of the spacers 41a and 41b is not particularly limited, but is preferably 50 μm or more, and more preferably 75 μm or more, from the viewpoint of preventing deflection which is considered to easily occur when the spacer has a large area. From the viewpoint of easy releasability of the separator, it is preferably 300 μm or less, and more preferably 200 μm or less.

The thickness of the separator 41b is not particularly limited, but is preferably 10 μm or more, and more preferably 25 μm or more, from the viewpoint of handleability when the separator is peeled off. From the viewpoint of easy releasability of the separator, it is preferably 200 μm or less, and more preferably 100 μm or less.

Next, a method for manufacturing a semiconductor device using the sealing sheet 10 with spacers on both sides will be described.

(method of manufacturing semiconductor device)

A method for manufacturing a semiconductor device according to this embodiment will be described below with reference to fig. 2 to 10. Fig. 2 to 10 are schematic cross-sectional views for explaining the method of manufacturing the semiconductor device according to the present embodiment. First, a method of manufacturing a semiconductor device called a Fan-out (Fan-out) Wafer Level Package (WLP) will be described below.

The method for manufacturing a semiconductor device according to this embodiment includes at least:

a step A of preparing a laminate in which a semiconductor chip is temporarily fixed to a temporary fixing material;

a step B of preparing a sealing sheet with a separator;

a step C of disposing the sealing sheet with the spacer on the semiconductor chip of the laminate; and

and a step D of embedding the semiconductor chip in the sealing sheet to form a sealed body in which the semiconductor chip is embedded in the sealing sheet.

[ preparation of laminate ]

As shown in fig. 2, in the method for manufacturing a semiconductor device according to the present embodiment, first, a laminate 50 in which a semiconductor chip 53 is temporarily fixed to a temporary fixing member 60 is prepared (step a). The laminate 50 is obtained, for example, by the following temporary fixing material preparation step and semiconductor chip temporary fixing step.

< temporary fixing Material preparation Process >

In the temporary fixing material preparation step, a temporary fixing material 60 (see fig. 2) in which a thermally expandable adhesive layer 60a is laminated on a support base 60b is prepared. In addition, a radiation-curable pressure-sensitive adhesive layer may be used instead of the thermally expandable pressure-sensitive adhesive layer. In the present embodiment, the temporary fixing material 60 including the thermally expandable adhesive layer will be described. However, the temporary fixing material in which the heat-expandable adhesive layer is laminated on the support base material is described in detail in japanese patent application laid-open publication No. 2014-015490 and the like, and therefore, the description will be made briefly below.

(Heat-expandable adhesive layer)

The thermally expandable adhesive layer 60a may be formed by an adhesive composition including a polymer component and a foaming agent. As the polymer component (particularly, base polymer), an acrylic polymer (sometimes referred to as "acrylic polymer a") can be suitably used. Examples of the acrylic polymer a include polymers containing a (meth) acrylate as a main monomer component. Examples of the (meth) acrylic acid ester include alkyl (meth) acrylates (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl, octadecyl, and eicosyl esters, and the like, linear or branched alkyl esters having 1 to 30 carbon atoms, particularly 4 to 18 carbon atoms) and cycloalkyl (meth) acrylates (e.g., cyclopentyl, cyclohexyl, and the like). These (meth) acrylates may be used alone or in combination of 2 or more.

The acrylic polymer a may contain units corresponding to other monomer components copolymerizable with the (meth) acrylic acid ester, as necessary, for the purpose of modifying cohesive force, heat resistance, crosslinking properties, and the like.

The weight average molecular weight of the acrylic polymer a is not particularly limited, but is preferably 35 to 100 ten thousand, and more preferably about 45 to 80 ten thousand.

The thermally expandable adhesive layer 60a contains a foaming agent for imparting thermal expansion properties as described above. Therefore, in a state where the seal body 58 is formed on the thermally expandable adhesive layer 60a of the temporary fixing member 60 (see fig. 6), the temporary fixing member 60 is heated at least partially at any time, and the foaming agent contained in the heated portion of the thermally expandable adhesive layer 60a is foamed and/or expanded, whereby the thermally expandable adhesive layer 60a is expanded at least partially, and the adhesive surface (interface with the seal body 58) corresponding to the expanded portion is deformed in a concave-convex shape by the expansion of at least part of the thermally expandable adhesive layer 60a, whereby the adhesive force between the thermally expandable adhesive layer 60a and the seal body 58 is reduced, and the seal body 58 can be peeled off from the temporary fixing member 60 (see fig. 7).

(foaming agent)

The foaming agent used for the thermally expandable pressure-sensitive adhesive layer 60a is not particularly limited, and may be appropriately selected from known foaming agents. The blowing agents may be used alone or in combination of 2 or more. As the foaming agent, thermally expandable microspheres can be suitably used.

(Heat-expandable microspheres)

The thermally expandable microspheres are not particularly limited, and may be appropriately selected from known thermally expandable microspheres (various inorganic thermally expandable microspheres, organic thermally expandable microspheres, or the like). As the thermally expandable microspheres, a microencapsulated foaming agent can be suitably used from the viewpoint of ease of mixing operation and the like. Examples of such heat-expandable microspheres include microspheres in which a substance that is easily vaporized and expanded by heating, such as isobutane, propane, or pentane, is contained in an elastic shell. The shell is often formed of a thermally fusible material or a material that is broken by thermal expansion. Examples of the material forming the shell include a vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone.

The thickness of the heat-expandable pressure-sensitive adhesive layer is not particularly limited, and may be appropriately selected depending on the lowering property of the adhesive strength, and is, for example, about 5 μm to 300 μm (preferably about 20 μm to 150 μm).

The thermally expandable adhesive layer may be a single layer or a multilayer.

In the present embodiment, the thermally expandable pressure-sensitive adhesive layer may contain various additives (for example, a colorant, a thickener, an extender, a filler, an adhesion-imparting agent, a plasticizer, an antioxidant, a surfactant, a crosslinking agent, and the like).

(supporting base Material)

The support base 60b is a thin plate-like member that serves as a strength base of the temporary fixing member 60. The material of the support base 60b may be appropriately selected in consideration of handling property, heat resistance, and the like, and for example, a metal material such as SUS, a plastic material such as polyimide, polyamideimide, polyether ether ketone, polyether sulfone, or the like, glass, a silicon wafer, or the like can be used. Among them, SUS plates are preferable from the viewpoint of heat resistance, strength, recyclability, and the like.

The thickness of the supporting base material 60b may be selected as appropriate in consideration of the target strength or handling property, and is preferably 100 to 5000 μm, and more preferably 300 to 2000 μm.

(method of Forming temporary fixing Material)

The temporary fixing material 60 can be obtained by forming a thermally expandable adhesive layer 60a on the support base 60 b. The heat-expandable pressure-sensitive adhesive layer can be formed by a conventional method of mixing a pressure-sensitive adhesive, a foaming agent (heat-expandable microspheres, etc.), and a solvent or other additives used as needed to form a sheet-like layer. Specifically, the heat-expandable adhesive layer can be formed, for example, by a method of applying a mixture containing a binder, a foaming agent (heat-expandable microspheres or the like), and a solvent or other additives used as needed to the supporting base 60b, a method of applying the mixture to an appropriate separator (release paper or the like) to form a heat-expandable adhesive layer, and transferring (transferring) the heat-expandable adhesive layer to the supporting base 60b, or the like.

(method of thermal expansion of thermally expandable adhesive layer)

In this embodiment, the heat-expandable adhesive layer can be thermally expanded by heating. The heat treatment may be performed by using an appropriate heating means such as a hot plate, a hot air dryer, a near infrared lamp, or an air dryer. The heating temperature at the time of the heat treatment may be equal to or higher than the foaming start temperature (thermal expansion start temperature) of the foaming agent (thermal expansion microspheres, etc.) in the thermal expansion adhesive layer, and the conditions of the heat treatment may be appropriately set depending on the reduction of the bonding area due to the type of the foaming agent (thermal expansion microspheres, etc.), the heat resistance of the sealing body including the support base material and the semiconductor chip, the heating method (heat capacity, heating means, etc.), and the like. The temperature is 100 to 250 ℃, 1 to 90 seconds (hot plate, etc.), or 5 to 15 minutes (hot air dryer, etc.) as a general heat treatment condition. The heat treatment may be performed at an appropriate stage according to the purpose of use. In addition, as a heat source in the heating treatment, an infrared lamp or heated water may be used.

< semiconductor chip temporary fixing step >

In the semiconductor chip temporary fixing step, the plurality of semiconductor chips 53 are arranged on the prepared temporary fixing member 60 so that the circuit forming surface 53a thereof faces the temporary fixing member 60, and temporarily fixed (see fig. 2). For temporary fixing of the semiconductor chip 53, a known apparatus such as a flip chip bonder or a die bonder can be used.

The layout and the number of semiconductor chips 53 may be set as appropriate according to the shape and size of the temporary fixing material 60, the number of production target packages, and the like, and may be arranged in a matrix array of a plurality of rows and a plurality of columns, for example. The shape and size of the laminate 50 (temporary fixing material 60) in a plan view are not particularly limited, and may be the same as those of the separator-equipped sealing sheet 10. In the above, an example of the laminate preparation step is shown.

[ Process for preparing a sealing sheet having spacers on both sides ]

In the method for manufacturing a semiconductor device according to the present embodiment, a sealing sheet 10 (see fig. 1) having spacers on both sides is prepared (step B).

[ Process of lifting the sealing sheet having spacers on both sides ]

After the step B, as shown in fig. 3, the sealing sheet 10 with spacers on both sides is lifted up by the suction chuck 19 via the spacer 41 a. The interface between the separator 41a and the sealing sheet 11 of the sealing sheet 10 with separators on both sides and the interface between the sealing sheet 11 and the separator 41b are bonded with a peeling force of such an extent that they are not peeled off by their own weight.

In the present embodiment, since the product α of the thickness t [ mm ] of the sealing sheet 40 and the storage elastic modulus G' [ Pa ] at 50 ℃ satisfies the above formula 1, the sealing sheet 40 can be suppressed from being deflected to form a gap between the suction collet 19 and the sealing sheet 10 with a separator on both sides. As a result, the sealing sheet 10 with spacers on both sides can be prevented from falling off the suction chuck 19.

[ step of peeling separator from sealing sheet having separators on both sides ]

Subsequently, the separator 41b is peeled off from the sealing sheet 10 with separators on both sides. The peeling force at the interface between the separator 41a and the sealing sheet 40 of the sealing sheet 10 with separators on both sides is such that the separator 41b does not peel off when peeled off.

[ Process for disposing sealing sheet and laminate ]

Next, as shown in fig. 4, the laminate 50 is placed on the lower heating plate 62 so that the surface to which the semiconductor chip 53 is temporarily fixed faces upward, and the sealing sheet 40 with the spacer 41a is placed on the surface of the laminate 50 to which the semiconductor chip 53 is temporarily fixed (step C). In this step, the laminate 50 may be first placed on the lower heating plate 62, and then the sealing sheet 40 with the separator 41a may be placed on the laminate 50, or the sealing sheet 40 with the separator 41a may be first placed on the laminate 50, and then the laminate formed by laminating the laminate 50 and the sealing sheet 40 with the separator 41a may be placed on the lower heating plate 62.

[ procedure for Forming sealing body ]

Next, as shown in fig. 5, the semiconductor chip 53 is embedded in the sealing sheet 40 by hot pressing with the lower hot plate 62 and the upper hot plate 64, and the sealing body 58 in which the semiconductor chip 53 is embedded in the sealing sheet 40 is formed (step D). The sealing sheet 40 functions as a sealing resin for protecting the semiconductor chip 53 and its accompanying elements from the external environment. This makes it possible to obtain the sealing body 58 in which the semiconductor chip 53 temporarily fixed to the temporary fixing member 60 is embedded in the sealing sheet 40.

Specifically, the hot pressing conditions for embedding the semiconductor chip 53 in the sealing sheet 40 are preferably 40 to 150 ℃, more preferably 60 to 120 ℃, a pressure of, for example, 0.1 to 10MPa, preferably 0.5 to 8MPa, and a time of, for example, 0.3 to 10 minutes, preferably 0.5 to 5 minutes. Further, as the hot pressing method, parallel plate pressing or roll pressing may be mentioned. Among them, parallel flat plate stamping is preferable.

This makes it possible to obtain a semiconductor device in which the semiconductor chip 53 is embedded in the sealing sheet 40. In consideration of improvement in adhesion and conformability of the sealing sheet 40 to the semiconductor chip 53 and the temporary fixing material 60, it is preferable to perform pressing under reduced pressure.

The pressure is, for example, 0.1 to 5kPa, preferably 0.1 to 100Pa, and the reduced pressure holding time (time from the start of the pressure reduction to the start of the pressing) is, for example, 5 to 600 seconds, preferably 10 to 300 seconds.

[ other Process for peeling separator ]

Subsequently, the other separator 41a is peeled off (see fig. 6).

[ Heat curing Process ]

Next, the sealing sheet 40 is thermally cured. Specifically, for example, the entire sealing body 58 in which the semiconductor chip 53 temporarily fixed to the temporary fixing member 60 is embedded in the sealing sheet 40 is heated.

The heating temperature is preferably 100 ℃ or higher, and more preferably 120 ℃ or higher as the conditions for the heat curing treatment. On the other hand, the upper limit of the heating temperature is preferably 200 ℃ or less, more preferably 180 ℃ or less. The heating time is preferably 10 minutes or more, and more preferably 30 minutes or more. On the other hand, the upper limit of the heating time is preferably 180 minutes or less, and more preferably 120 minutes or less. If necessary, the pressure may be increased, preferably to 0.1MPa or more, more preferably to 0.5MPa or more. On the other hand, the upper limit is preferably 10MPa or less, more preferably 5MPa or less.

[ procedure for peeling Heat-Expandable adhesive layer ]

Next, as shown in fig. 7, the heat-expandable adhesive layer 60a is thermally expanded by heating the temporary fixing material 60, so that peeling is performed between the heat-expandable adhesive layer 60a and the sealing body 58. Alternatively, the following steps may also be suitably employed: the support base 60b and the thermal expansion adhesive layer 60a are peeled off at the interface, and then the thermal expansion adhesive layer 60a and the sealing body 58 are peeled off at the interface by thermal expansion. In either case, the thermal expansion adhesive layer 60a is heated to thermally expand and reduce the adhesive force thereof, so that the interface between the thermal expansion adhesive layer 60a and the sealing body 58 can be easily peeled. As the conditions for thermal expansion, the conditions in the column "thermal expansion method of a thermally expandable adhesive layer" described above can be appropriately adopted. In particular, the heat-expandable pressure-sensitive adhesive layer is preferably configured not to be peeled off by heating in the heat curing step but to be peeled off by heating in the heat-expandable pressure-sensitive adhesive layer peeling step.

[ Process of grinding the sealing sheet ]

Next, as shown in fig. 8, the sealing sheet 40 of the sealing body 58 is ground as necessary to develop the back surface 53c of the semiconductor chip 53. The method of grinding the sealing sheet 40 is not particularly limited, and examples thereof include a grinding method using a grinding wheel rotating at a high speed.

(rewiring formation Process)

In the present embodiment, it is preferable to further include a rewiring forming step of forming rewirings 69 on the circuit forming surface 53a of the semiconductor chip 53 of the sealing body 58. In the rewiring forming step, after the temporary fixing member 60 is peeled off, the rewiring 69 (see fig. 9) connected to the exposed semiconductor chip 53 is formed on the sealing body 58.

As a method for forming the rewiring, for example, a metal seed layer may be formed on the exposed semiconductor chip 53 by a known method such as a vacuum film forming method, and the rewiring 69 may be formed by a known method such as a semi-additive method.

Then, an insulating layer such as polyimide or PBO may be formed on the rewiring 69 and the sealing body 58.

(bump formation Process)

Next, a bump process of forming a bump 67 on the formed rewiring 69 may be performed (see fig. 9). The bumping process may be performed by a known method such as solder ball or solder plating.

(cutting Process)

Finally, the laminate including the semiconductor chip 53, the sealing sheet 40, the rewiring 69, and other elements is cut (see fig. 10). This makes it possible to obtain a semiconductor device 59 in which the wiring is led out to the outside of the chip region.

In the above-described embodiment, a description has been given of a case where the "laminated body" of the present invention is the "laminated body 50 in which the semiconductor chip 53 is temporarily fixed to the temporary fixing member 60". However, the "laminate" in the present invention is not limited to this example, and may be any laminate in which a semiconductor chip is fixed to a support having a certain degree of strength. That is, the "laminate" may be a "laminate in which a semiconductor chip is fixed to a support". Examples of the "laminate" in the present invention include "a laminate in which a semiconductor Chip is flip-Chip bonded to a circuit formation surface of a semiconductor Wafer" (so-called Chip on Wafer) "and" a laminate in which a semiconductor Chip is mounted on an organic substrate ".