阅读说明：本技术 层叠体 (Laminated body ) 是由 三田亮太 市川智昭 于 2021-06-25 设计创作，主要内容包括：本发明提供一种层叠体,其具备基材片、以及层叠于该基材片且含有金属颗粒的含金属颗粒层,前述基材片具有与前述含金属颗粒层接触的接触面,通过纳米压痕法测定前述接触面而求出的前述基材片在23℃下的杨氏模量为0.01～10GPa。(The present invention provides a laminate comprising a substrate sheet and a metal-containing particle layer laminated on the substrate sheet and containing metal particles, wherein the substrate sheet has a contact surface that is in contact with the metal-containing particle layer, and the Young's modulus of the substrate sheet at 23 ℃ determined by measuring the contact surface by a nanoindentation method is 0.01 to 10 GPa.)

1. A laminate comprising a base sheet and a metal-containing particle layer containing metal particles and laminated on the base sheet,

the substrate sheet has a contact surface in contact with the metal-containing particle layer,

the substrate sheet has a Young's modulus at 23 ℃ of 0.01 to 10GPa as measured on the contact surface by a nanoindentation method.

2. The laminate according to claim 1, wherein the substrate sheet has a single layer or a plurality of layers and is provided with at least 1 resin layer,

the surface of the resin layer serves as the contact surface, and the total thickness of the resin layer is 10 to 5000 [ mu ] m.

3. The laminate according to claim 1 or 2, wherein the metal-containing particle layer is laminated on the substrate sheet in a state of being peelable from the substrate sheet,

the adhesive sheet is used by pressing a part of the metal-containing particle layer against the base sheet to be cut, and the cut part is peeled off from the base sheet and attached to an adherend.

4. The laminate according to claim 1 or 2, wherein a content ratio of the metal particles in the metal-containing particle layer is 85 to 97% by mass.

5. The laminate of claim 1 or 2, wherein the metal particles comprise at least 1 metal selected from the group consisting of silver, copper, silver oxide, and copper oxide.

6. The laminate according to claim 1 or 2, wherein the metal-containing particle layer has a shear failure strength of 2 to 40MPa at 23 ℃ and a minimum load of 30 to 100 μ N which is achieved during unloading when load-displacement measurement is performed by a nanoindentation method at 23 ℃.

Technical Field

The present invention relates to a laminate.

Background

Conventionally, in the manufacture of semiconductor devices, paste compositions containing metal particles have been used for bonding semiconductor chips (hereinafter also referred to as "chips") to lead frames or the like (for example, patent documents 1 and 2).

In addition, a method is known in which a film is formed from the paste composition, a part of the film is transferred to a chip, and the chip is bonded to a lead frame or the like via the film (for example, patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-039580

Patent document 2: japanese patent laid-open No. 2014-111800

Patent document 3: japanese Kokai publication Hei 2014-503936

Disclosure of Invention

Problems to be solved by the invention

However, the film may not be sufficiently transferred to an adherend (chip or the like), and the adherend may not be sufficiently bonded to a lead frame or the like.

In view of the above problems, an object of the present invention is to provide a laminate excellent in transferability.

Means for solving the problems

The laminate of the present invention comprises a base sheet and a metal particle-containing layer laminated on the base sheet and containing metal particles,

the substrate sheet has a contact surface in contact with the metal-containing particle layer,

the substrate sheet has a Young's modulus at 23 ℃ of 0.01 to 10GPa as determined by measuring the contact surface by a nanoindentation method.

Drawings

Fig. 1 is a schematic cross-sectional view of a laminate according to the present embodiment.

Fig. 2 is a schematic cross-sectional view showing a state where the semiconductor chip B is picked up from the dicing tape a by the suction collet C.

Fig. 3 is a schematic sectional view showing the case of the transfer process.

Fig. 4 is a schematic sectional view showing the case of the pickup process.

Fig. 5 is a schematic sectional view showing a state immediately before the semiconductor chip B with the metal particle layer 2 is pressed against the lead frame D from the metal particle layer 2 side by the suction collet C.

Fig. 6 is a schematic sectional view showing the case of the sintering process.

Description of the reference numerals

1: laminate, 2: metal-containing particle layer, 3: substrate sheet, 3 a: a contact surface,

31: a resin layer,

A: cutting the belt, B: semiconductor chip, C: adsorption collet chuck, D: lead frame, E: pressure heating device, F: semiconductor device, G: platform and H: table (Ref. Table)

Detailed Description

Hereinafter, an embodiment of the present invention will be described by taking as an example a case where the metal-containing particle layer of the laminate of the present embodiment is a sinterable layer, with reference to the drawings.

The metal particle layer of the laminate of the present embodiment is a layer that is used by being bonded to an adherend by sintering.

As shown in fig. 1, the laminate 1 of the present embodiment includes: a base sheet 3, and a metal particle-containing layer 2 laminated on the base sheet 3 and containing metal particles.

The substrate sheet 3 is a resin layer 31 containing a resin.

The substrate sheet 3 has a contact surface 3a that is in contact with the metal-containing particle layer 2. Specifically, the resin layer 31 has a contact surface 3a that is in contact with the metal-containing particle layer 2.

The metal-containing particle layer 2 is laminated on the base sheet 3 in a state of being peelable from the base sheet 3.

The laminate 1 of the present embodiment is used by pressing a part of the metal-containing particle layer 2 against the substrate sheet 3 to cut it, and the cut part is peeled off from the substrate sheet 3 and adhered to an adherend (for example, a chip or the like).

More specifically, in the laminate 1 of the present embodiment, the metal-containing particle layer 2 is pressed by a pressing member that presses a part of the metal-containing particle layer 2 toward the substrate sheet 3, a part of the metal-containing particle layer 2 is cut and used, and the cut part is peeled from the substrate sheet 3 and adhered to an adherend (for example, a chip or the like).

Examples of the resin contained in the resin layer 31 include polyolefin resin, polyester resin, polyurethane resin, polycarbonate resin, polyether ether ketone resin, polyimide resin, polyether imide resin, polyamide resin, polyvinyl chloride, polyvinylidene chloride, polyphenylene sulfide resin, fluororesin, cellulose resin, silicone resin, and the like.

The resin may be an ionomer resin.

Examples of the polyolefin resin include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, polymethylpentene, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid copolymer, an ethylene- (meth) acrylate copolymer, an ethylene-butene copolymer, and an ethylene-hexene copolymer.

Examples of the polyester resin include polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate.

Examples of the polyamide resin include wholly aromatic polyamide (aramid) and the like.

Examples of the fluororesin include Polytetrafluoroethylene (PTFE).

The resin layer 31 may be formed of a film.

The film may be a uniaxially stretched film or a biaxially stretched film.

The resin layer 31 may be a porous body.

The Young's modulus of the substrate sheet 3 at 23 ℃ determined by measuring the contact surface 3a by the nanoindentation method is important to be 0.01 to 10GPa, preferably 0.02 to 8GPa, more preferably 0.1 to 5GPa, and particularly preferably 0.3 to 3.4 GPa.

In other words, it is important that the Young's modulus at 23 ℃ as measured by the nanoindentation method with respect to the contact surface 3a of the substrate sheet 3 is 0.01 to 10GPa, preferably 0.02 to 8GPa, more preferably 0.1 to 5GPa, and particularly preferably 0.3 to 3.4 GPa.

The laminate 1 of the present embodiment has the following advantages in that the young's modulus is 10GPa or less: when an adherend (for example, a chip or the like) is pressed against the metal-containing particle layer 2, a force is easily applied to the entire part of the metal-containing particle layer 2 in contact with the adherend, and as a result, the metal-containing particle layer 2 can be sufficiently transferred to the adherend.

In addition, the laminate 1 of the present embodiment has the following advantages in that the young's modulus is 0.01GPa or more: when an adherend is pressed against the metal-containing particle layer 2, a force is easily applied sufficiently in the direction in which the adherend is pressed, and as a result, the metal-containing particle layer 2 can be sufficiently transferred to the adherend.

The young's modulus can be determined by the nanoindentation method of ISO14577 (instrument indentation test).

Specifically, the measurement can be performed under the following conditions using a microhardness tester (DUH-211, manufactured by Shimadzu corporation).

Pressure head: berkovich indenter

Test mode: load-unload test

Test force: 0.98mN

Minimum test force: 0.002mN

Load and unloading speed: 1.0 mN/sec

Load retention time: 5.0 second

Unloading holding time: 5.0 second

With correction of Cf-Ap

The nanoindentation method is a method for measuring each physical property of a sample on a nanometer scale. In the nanoindentation method, at least a process of pushing the indenter into the sample mounted on the stage (a load applying process) and a process of subsequently pulling the indenter out of the sample (an unloading process) are performed, and the load acting between the indenter and the sample and the relative displacement of the indenter with respect to the sample are measured in a series of processes. As a result, a load-displacement curve was obtained. From the load-displacement curve, physical properties (hardness, elastic modulus, adhesive force, etc.) of the sample measured on a nanometer scale can be obtained.

The total thickness of the resin layer 31 is preferably 10 to 5000 μm, more preferably 20 to 4000 μm, and still more preferably 30 to 3000 μm.

The laminate 1 of the present embodiment has an advantage of excellent handleability because the total thickness of the resin layers 31 is 10 μm or more.

In addition, the laminate 1 of the present embodiment has an advantage that the total thickness of the resin layer 31 is 5000 μm or less, thereby reducing the material cost.

In this embodiment, the thickness of the layer can be measured by a dial gauge.

The foregoing metal-containing particle layer 2 contains metal particles and a binder. In addition, the metal-containing particle layer 2 may contain a plasticizer or the like.

The binder includes a polymer binder and a binder other than a polymer (hereinafter, also referred to as a "low-molecular binder").

The metal-containing particle layer 2 is a sintering layer.

The sinterable layer is a layer that can be sintered by heating.

The metal particles are sintered metal particles.

In addition, the metal particles are conductive metal particles. The metal-containing particle layer 2 serves as an adhesive surface for adhering one surface side and the other surface side to an adherend, respectively, and is used for electrically connecting the adherends to each other.

Examples of the metal particles include gold, silver, copper, palladium, tin, nickel, and alloys thereof.

Further, the metal particles may be metal oxides. Examples of the metal oxide include silver oxide, copper oxide, palladium oxide, and tin oxide.

The aforementioned metal particles may be particles having a core-shell structure. Examples of the particles having a core-shell structure include particles including a core made of copper and a shell made of gold, silver, or the like covering the core.

The metal particles preferably contain at least 1 metal selected from the group consisting of silver, copper, silver oxide, and copper oxide, from the viewpoint that the metal-containing particle layer 2 can be a sintered layer firmly adhered to an adherend after sintering.

In addition, from the viewpoint that the metal-containing particle layer 2 is excellent in electrical conductivity and thermal conductivity after sintering, the metal particles preferably contain at least 1 metal selected from the group consisting of silver and copper.

In addition, the metal particles preferably contain silver particles from the viewpoint of oxidation resistance. Even if sintered in an air atmosphere, the silver particles are difficult to oxidize.

The metal particles are contained in the metal-containing particle layer 2 in the form of primary particles or as secondary particles formed by aggregating a plurality of primary particles.

From the viewpoint of easily ensuring the flatness of the surface of the metal-containing particle layer 2, the volume-based median particle diameter (D50) of the metal particles is preferably 10000nm or less, more preferably 3000nm or less, still more preferably 1000nm or less, and particularly more preferably 500nm or less.

From the viewpoint of improving the dispersibility of the metal particles in the metal-containing particle layer 2, the volume-based median particle diameter (D50) of the metal particles is preferably 1nm or more, more preferably 10nm or more, and still more preferably 50nm or more.

The volume-based median particle diameter (D50) of the metal particles was determined by using a Scanning Electron Microscope (SEM).

That is, the area of each metal particle observed from one direction by a Scanning Electron Microscope (SEM) was determined.

Next, assuming that each metal particle is a true sphere, the diameter and volume of each metal particle are determined. When the metal particles are secondary particles, the diameter and volume of the secondary particles are determined.

Further, a volume-based particle size distribution is obtained from the data of the diameter and volume of each metal particle, and a volume-based median diameter of the metal particle is obtained from the volume-based particle size distribution (D50).

The polymer binder is preferably a pyrolyzable polymer binder.

The pyrolytic polymer binder is a binder that is pyrolyzed at a sintering temperature. The pyrolytic polymer binder is an element that retains the shape of the metal-containing particle layer 2 until sintering.

In the present embodiment, the pyrolytic polymer binder is preferably solid at room temperature (23 ℃) from the viewpoint of easily retaining the shape of the metal-containing particle layer 2. Examples of the pyrolytic polymer binder include polycarbonate resins and acrylic resins.

Examples of the polycarbonate resin include aliphatic polycarbonates and aromatic polycarbonates.

The aromatic polycarbonate contains benzene rings between carbonate groups (-O-CO-O-) in the main chain.

The aliphatic polycarbonate contains an aliphatic chain between carbonate groups (-O-CO-O-) in the main chain and does not contain a benzene ring.

Examples of the aliphatic polycarbonate include polyethylene carbonate and polypropylene carbonate.

Examples of the aromatic polycarbonate include polycarbonates having a bisphenol a structure in the main chain.

The acrylic resin contains a (meth) acrylate as a constituent unit.

Examples of the (meth) acrylate include (meth) acrylates having a linear or branched alkyl group having 4 to 18 carbon atoms.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, a heptyl group, a cyclohexyl group, a 2-ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, an isodecyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a stearyl group, and an octadecyl group.

The aforementioned acrylic resin may contain a monomer other than a (meth) acrylate ester as a constituent unit.

Examples of the monomer other than the (meth) acrylate ester include a carboxyl group-containing monomer, an acid anhydride monomer, a hydroxyl group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, and the like.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and 4- (hydroxymethyl) cyclohexylmethyl (meth) acrylate.

Examples of the sulfonic acid group-containing monomer include styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxynaphthalenesulfonic acid.

Examples of the phosphoric acid group-containing monomer include 2-hydroxyethyl acryloyl phosphate and the like.

In the present embodiment, "(meth) acrylic acid" means a concept including acrylic acid and methacrylic acid.

In addition, "(meth) acrylate" is meant to include both acrylate and methacrylate concepts.

The weight average molecular weight of the polymer binder is preferably 10000 or more.

The weight average molecular weight is a weight average molecular weight measured by Gel Permeation Chromatography (GPC) and converted to polystyrene.

For example, the weight average molecular weight may be asThe following was found: using GPC "HLC-8320 GPC" available from Tosoh corporation as an apparatus, a column "TSK guardcolumn H available from Tosoh corporation_HR(S) "and column" TSK GMH manufactured by Tosoh corporation_HRH (S) "and TSK GMH column manufactured by Tosoh corporation_HRThe total of 3 columns such as-H (S) ", which were used as columns in series, were subjected to GPC measurement using" TSK gel SuperH-RC "as a reference column and tetrahydrofuran as an eluent at a column temperature of 40 ℃ and a flow rate of 0.5 ml/min, and the values were calculated from the results obtained and obtained as values in terms of polystyrene.

The low-molecular-weight binder preferably contains a low-boiling-point binder having a boiling point lower than the pyrolysis starting temperature of the pyrolyzable polymer binder.

In addition, the low molecular binder is preferably liquid or semi-liquid at 23 ℃.

Further, the low-molecular binder preferably exhibits a viscosity of 1X 10 at 23 ℃⁵Pa · s or less.

The viscosity can be measured by a dynamic viscoelasticity measuring apparatus (trade name "HAAKE MARS III", manufactured by Thermo Fisher scientific Co., Ltd.). In the measurement, use is made ofThe parallel plates of (1) were used as a jig, and the gap between the plates was set to 100 μm and the shear rate of the rotary shear was set to 1s^-1。

Examples of the low-molecular-weight binder include alcohols and ethers.

Examples of the alcohols include terpene alcohols.

Examples of the terpene alcohols include isobornyl cyclohexanol, citronellol, geraniol, nerol, carveol, and α -terpineol.

Examples of the alcohols other than the terpene alcohols include pentanol, hexanol, heptanol, octanol, 1-decanol, ethylene glycol, diethylene glycol, propylene glycol, butanediol, and 2, 4-diethyl-1, 5-pentanediol.

Examples of the ethers include alkylene glycol alkyl ethers.

Examples of the alkylene glycol alkyl ether include ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol isobutyl ether, diethylene glycol hexyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, diethylene glycol isopropyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, propylene glycol propyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, dipropylene glycol butyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, and tripropylene glycol dimethyl ether.

Examples of ethers other than the alkylene glycol alkyl ethers include ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, dipropylene glycol methyl ether acetate, and the like.

From the viewpoint of stability at room temperature, the low-molecular-weight binder is preferably a terpene alcohol, more preferably isobornyl cyclohexanol.

The content ratio of the metal particles in the metal-containing particle layer 2 is preferably 85 to 97% by mass, and more preferably 88 to 96% by mass.

The metal-containing particle layer 2 has an advantage that it is easy to sufficiently exhibit conductivity after sintering by containing 85 mass% or more of metal particles.

In addition, the metal-containing particle layer 2 contains metal particles in an amount of 97 mass% or less, and thus has an advantage that the shape of the metal-containing particle layer 2 is easily maintained.

The content ratio of the polymer binder in the metal-containing particle layer 2 is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass.

The metal-containing particle layer 2 has an advantage that the shape of the metal-containing particle layer 2 is easily maintained by containing the polymer binder in an amount of 0.1 mass% or more.

In addition, the metal-containing particle layer 2 has an advantage that a residue component derived from the polymer binder after sintering can be reduced by containing 10 mass% or less of the polymer binder.

The content ratio of the low-molecular binder in the metal-containing particle layer 2 is preferably 1 to 20% by mass, and more preferably 2 to 15% by mass.

The metal-containing particle layer 2 has an advantage of excellent transferability to an adherend by containing 1 mass% or more of a low molecular binder.

In addition, the metal-containing particle layer 2 has an advantage that a residue component derived from the low-molecular binder after sintering can be reduced by containing the low-molecular binder in an amount of 20 mass% or less.

The thickness of the metal-containing particle layer 2 is preferably 5 μm or more, and more preferably 10 μm or more.

The thickness of the metal-containing particle layer 2 is preferably 300 μm or less, and more preferably 150 μm or less.

The laminate 1 of the present embodiment has an advantage that the surface of the metal-containing particle layer 2 can be made flat by setting the thickness of the metal-containing particle layer 2 to 5 μm or more.

In addition, the laminate 1 of the present embodiment has an advantage that cracks can be suppressed during handling by setting the thickness of the metal-containing particle layer 2 to 300 μm or less.

The metal-containing particle layer 2 preferably has a shear fracture strength of 2 to 40MPa, more preferably 2 to 35MPa, and still more preferably 2 to 32MPa at 23 ℃.

The laminate 1 of the present embodiment has an advantage that the metal-containing particle layer 2 can easily maintain the shape of the metal-containing particle layer 2 because the shear fracture strength at 23 ℃ of the metal-containing particle layer 2 is 2MPa or more.

The laminate 1 of the present embodiment has an advantage of excellent cuttability when transferring to an adherend by setting the shear fracture strength of the metal-containing particle layer 2 at 23 ℃ to 40MPa or less.

The metal-containing particle layer 2 preferably has a shear fracture strength at 100 ℃ of 20MPa or less, more preferably 9MPa or less, and still more preferably 7MPa or less.

The laminate 1 of the present embodiment has an advantage of excellent cuttability when transferring to an adherend by setting the shear fracture strength of the metal-containing particle layer 2 at 100 ℃ to 20MPa or less.

The shear fracture strength can be determined by the SAICAS method.

For example, the shear fracture strength can be determined using saicas (surface And interface Cutting Analysis system) which is an apparatus manufactured by DAIPLA WINTES co.

Specifically, the shear strength when the metal-containing particle layer 2 was cut at a speed of 10 μm/sec in a direction parallel to the surface of the metal-containing particle layer 2 and at a speed of 0.5 μm/sec in a direction perpendicular to the surface of the metal-containing particle layer 2 using a cutting edge (insert width: 1mm, rake angle: 10 ° and relief angle: 10 °), was determined, and the shear strength was used as the shear fracture strength.

The shear fracture strength can be adjusted by adjusting at least one of the blending ratio of the polymer binder and the blending ratio of the low-molecular binder, or adjusting the viscoelasticity of the polymer binder.

The minimum load of the metal-containing particle layer 2 in the unloading process when the load-displacement measurement is performed by the nanoindentation method at 23 ℃ is preferably 30 to 100 μ N, more preferably 32 to 80 μ N, and still more preferably 35 to 75 μ N.

In the laminate 1 of the present embodiment, the minimum load of the metal-containing particle layer 2 at 23 ℃ is 30 μ N or more, and thus the metal-containing particle layer 2 is advantageously easily adhered to an adherend.

In the laminate 1 of the present embodiment, the minimum load at 23 ℃ of the metal-containing particle layer 2 is 100 μ N or less, and thus the following advantages are obtained: in the case where the metal-containing particle layer 2 is covered with a release substrate, the release substrate can be easily released from the metal-containing particle layer 2 as needed.

The nanoindentation method described above is the nanoindentation method of ISO14577 (instrument indentation test).

The load-displacement measurement by the nanoindentation method can be performed using a nanoindenter (trade name "Triboindenter", product of hysetron corporation).

The measurement conditions in the load-displacement measurement by the nanoindentation method may be as follows.

Measurement mode: single indentation assay

Using a pressure head: berkovich diamond indenter

Maximum load (set value) reached during load application: 500 mu N

Pressing speed of the indenter during load application: 100 μ N/sec

Pulling-out speed of the pressure head in unloading process: 100 μ N/sec

The metal-containing particle layer 2 may be formed on the substrate sheet 3 as follows.

First, a varnish is prepared by mixing each material of the metal-containing particle layer 2 with a solvent.

Next, the varnish is applied to the base sheet 3 to form a coating film, and the coating film is dried (the solvent in the coating film is volatilized), thereby forming the metal-containing particle layer 2.

Examples of the solvent include ketones and alcohols. Examples of the ketone include methyl ethyl ketone. Examples of the alcohol include methanol and ethanol.

In the laminate 1 of the present embodiment, the resin layer 31 (base sheet 3) preferably contains at least 1 resin selected from the group consisting of polyolefin resins, polyamide resins, and fluororesins, and is a porous body.

In the laminate 1 of the present embodiment, at least 1 resin selected from the group consisting of polyolefin resins, polyamide resins, and fluororesins is preferably an ionomer resin.

In the laminate 1 of the present embodiment, the metal-containing particle layer 2 preferably contains a pyrolyzable polymer binder as the polymer binder.

A method of using a laminate 1 according to the present embodiment is a method of using a laminate 1 including a base sheet 3 and a metal-containing particle layer containing metal particles laminated in a peelable state on the base sheet 3, the method including:

pressing the metal-containing particle layer 2 against the substrate sheet 3 to thereby cut off a part of the metal-containing particle layer 2; and the number of the first and second groups,

the cut metal-containing particle layer 2 is peeled off from the base sheet 3 and bonded to an adherend.

In the method of using the laminate of the present embodiment, the substrate sheet 3 has a contact surface 3a that is in contact with the metal-containing particle layer.

In the method of using the laminate of the present embodiment, the Young's modulus of the substrate sheet 3 at 23 ℃ as measured by the nanoindentation method with respect to the contact surface 3a is 0.01 to 10 GPa.

In other words, the Young's modulus at 23 ℃ of the substrate sheet 3 measured by the nanoindentation method with respect to the contact surface 3a is 0.01 to 10 GPa.

The young's modulus can be measured by the same method as that described in the laminate 1 of the present embodiment.

In the method of using the laminate of the present embodiment, the metal-containing particle layer 2 may be pressed by a pressing member that presses a part of the metal-containing particle layer 2 toward the substrate sheet 3.

In the method of using the laminate of the present embodiment, the adherend to which the cut metal-containing particle layer 2 is to be adhered may be a chip.

In the method of using the laminate of the present embodiment, it is preferable that the substrate sheet 3 has a single layer or a plurality of layers, and includes at least 1 resin layer 31, the surface of the resin layer 31 is a contact surface 3a, and the total thickness of the resin layer 31 is 10 to 5000 μm.

In the method of using the laminate of the present embodiment, the content ratio of the metal particles in the metal-containing particle layer 2 is preferably 85 to 97 mass% or less.

In the method of using the laminate of the present embodiment, it is preferable that the metal particles contain at least 1 metal selected from the group consisting of silver, copper, silver oxide, and copper oxide.

In the method of using the laminate of the present embodiment, it is preferable that the metal-containing particle layer 2 has a shear fracture strength of 2 to 40MPa at 23 ℃, and a minimum load of 30 to 100 μ N in an unloading process when a load-displacement measurement is performed by a nanoindentation method at 23 ℃.

The shear fracture strength at 23 ℃ and the minimum load achieved during unloading when the load-displacement measurement was performed by the nanoindentation method at 23 ℃ can be measured by the same methods as those described in the laminate 1 of the present embodiment.

Next, a method for manufacturing a semiconductor device according to this embodiment will be described.

First, a wafer is cut on a dicing tape to obtain semiconductor chips.

Next, as shown in fig. 2, the semiconductor chip B is picked up from the dicing tape a by the suction collet C.

The semiconductor chip B is generally rectangular in plan view, and more specifically, square in plan view. The thickness of the semiconductor chip B is, for example, 10 to 500 μm, more specifically, 20 to 400 μm. The area of the semiconductor chip B in plan view is, for example, 0.01 to 1000mm²More specifically, it is 0.04 to 500mm²。

As shown in fig. 3, the laminate 1 is placed on the stage G such that the metal-containing particle layer 2 of the laminate 1 is located on the upper side. The semiconductor chip B with the metal particle-containing layer 2 is obtained by pressing the semiconductor chip B against the metal particle-containing layer 2 of the laminate 1 with the suction collet C, and transferring a part of the metal particle-containing layer 2 to the semiconductor chip B (transfer step). The pressure for pressing the semiconductor chip B against the metal-containing particle layer 2 is preferably 0.01 to 10MPa, more preferably 0.1 to 5 MPa. The temperature of the suction collet C or the stage G when the semiconductor chip B is pressed against the metal-containing particle layer 2 is preferably 40 to 150 ℃, and more preferably 50 to 120 ℃.

Next, as shown in fig. 4, the semiconductor chip B with the metal-containing particle layer 2 is picked up from the laminate 1 by the suction collet C (picking-up step).

Then, as shown in fig. 5, the lead frame D is mounted on the stage H. The semiconductor chip B with the metal particle layer 2 is pressed against the lead frame D from the metal particle layer 2 side by a suction collet C, and the semiconductor chip B is pressure-bonded to the lead frame D via the metal particle layer 2. The pressure for pressing the semiconductor chip B with the metal particle-containing layer 2 against the lead frame D from the metal particle-containing layer 2 side is preferably 0.01 to 10MPa, more preferably 0.1 to 5 MPa. The temperature of the suction collet C or the stage H when the semiconductor chip B with the metal particle layer 2 is pressed against the lead frame D from the metal particle layer 2 side is preferably 40 to 150 ℃, and more preferably 50 to 120 ℃.

The thickness of the lead frame D is, for example, 10 to 2000 μm, more specifically, 400 to 1500 μm.

Next, as shown in fig. 6, the metal particle-containing layer 2 is heated while being pressurized by the pressure heating apparatus E, and the metal particles of the metal particle-containing layer 2 are sintered (sintering step), thereby obtaining a semiconductor device F.

After the sintering process, the bonding wire can be bonded to a desired position.

The laminate of the present invention is not limited to the above embodiment. The laminate of the present invention is not limited to the above-described effects. Further, the laminate of the present invention may be variously modified within a range not departing from the gist of the present invention.

For example, in the laminate of the present embodiment, the metal-containing particle layer is a sintering layer, but in the laminate of the present invention, the metal-containing particle layer may be a die-bonding thin film.

In the laminate of the present embodiment, the base sheet is the resin layer 31, but in the present invention, the base sheet may have a single layer or a plurality of layers. The substrate sheet may have 2 or more resin layers.

When the substrate sheet has 2 or more resin layers, the total thickness of the resin layers is a sum of the thicknesses of the resin layers.

The matters disclosed in the present specification include the following.

(1)

A laminate comprising a base sheet and a metal-containing particle layer containing metal particles and laminated on the base sheet,

the substrate sheet has a contact surface in contact with the metal-containing particle layer,

the substrate sheet has a Young's modulus at 23 ℃ of 0.01 to 10GPa as measured on the contact surface by a nanoindentation method.

The substrate sheet has a suitable cushioning property by having a Young's modulus of 0.01 to 10 GPa.

As a result, when an adherend is pressed onto the metal-containing particle layer, a part of the metal-containing particle layer can be sufficiently transferred to the adherend by the appropriate cushioning property of the substrate sheet.

Therefore, the laminate is excellent in transferability.

(2)

The laminate according to the above (1), wherein the substrate sheet has a single layer or a plurality of layers and comprises at least 1 resin layer,

the surface of the resin layer is the contact surface, and the thickness of the resin layer is 10 to 5000 μm.

According to the above configuration, not only excellent handling property but also low material cost can be obtained.

(3)

The laminate according to the above (1) or (2), wherein the metal-containing particle layer is laminated on the base sheet in a state of being peelable from the base sheet,

the metal particle-containing layer is partially cut by pressing the metal particle-containing layer against the base sheet, and the cut part is peeled off from the base sheet and bonded to an adherend.

(4)

The laminate according to any one of the above (1) to (3), wherein a content ratio of the metal particles in the metal-containing particle layer is 85 to 97% by mass.

According to the above configuration, the following advantages can be obtained: it is easy to exhibit sufficient conductivity after sintering and to maintain the shape of the metal-containing particle layer.

(5)

The laminate according to any one of the above (1) to (4), wherein the metal particles contain at least 1 metal selected from the group consisting of silver, copper, silver oxide and copper oxide.

According to the above configuration, the metal-containing particle layer can be a sintered layer which is firmly bonded to an adherend after sintering.

(6)

The laminate according to any one of the above (1) to (5), wherein the metal-containing particle layer has a shear fracture strength at 23 ℃ of 2 to 40MPa and a minimum load of 30 to 100 μ N in an unloading process when a load-displacement measurement is performed by a nanoindentation method at 23 ℃.

According to the above constitution, the following advantages can be obtained by setting the shear failure strength at 23 ℃ to 2 to 40 MPa: the shape of the metal-containing particle layer is easily maintained, and the cutting property is excellent when transferring the metal-containing particle layer to an adherend.

In addition, since the minimum load reached in the unloading process when the load-displacement measurement is performed by the nanoindentation method at 23 ℃ is 30 to 100 μ N, the following advantages can be obtained: the metal-containing particle layer is easily adhered to an adherend, and when the metal-containing particle layer is covered with a release substrate, the release substrate is easily released from the metal-containing particle layer as needed.

Examples

Next, the present invention will be specifically described by way of examples and comparative examples.

The following examples are intended to illustrate the present invention in further detail, and do not limit the scope of the present invention.

(example 1)

A varnish was prepared by mixing the following materials at the following mixing ratio for 3 minutes in a stirring mode of a mixer using a mixer (trade name: HM-500, manufactured by KEYENCE CORPORATION).

Silver particles as metal particles: 59.76 parts by mass

Polycarbonate resin (trade name "QPAC 40", weight average molecular weight: 150000, solid at ordinary temperature, manufactured by Empower Materials Co., Ltd.) as a polymer binder (pyrolytic polymer binder): 0.87 part by mass

Isobornyl cyclohexanol (trade name "Tersolve MTPH", liquid at room temperature, manufactured by Nippon Terpene Chemicals, inc.) as a low-molecular binder (low-boiling point binder): 0.87 part by mass

Methyl ethyl ketone as solvent: 35.91 parts by mass

The silver particles are used in a mass ratio of 9: 1 silver particles comprising first silver particles (volume-based median diameter (D50): 60nm, manufactured by DOWA ELECTRONICS co., ltd.) and second silver particles (volume-based median diameter (D50): 1100nm, manufactured by mitsui metal mining co).

Then, the varnish thus obtained was applied to a porous polyethylene sheet (porous PE sheet) (thickness: 300 μm) as a substrate sheet and then dried to form a metal-containing particle layer having a thickness of 54 μm, thereby obtaining a laminate. The drying temperature was set at 110 ℃ and the drying time was set at 3 minutes. The metal particle content in the metal particle-containing layer was 95% by mass.

(example 2)

A laminate was obtained in the same manner as in example 1, except that a polytetrafluoroethylene sheet (PTFE sheet) (thickness: 300 μm) was used as the substrate sheet instead of the porous PE sheet.

(example 3)

A laminate was obtained in the same manner as in example 1 except that a sheet (thickness: 250 μm) obtained by laminating 2 polyethylene films (PE films) (thickness: 125 μm) was used as the substrate sheet instead of the porous PE sheet.

(example 4)

A laminate was obtained in the same manner as in example 1 except that a sheet (thickness: 300 μm) obtained by laminating 3 sheets of polyethylene terephthalate films (PET films) (thickness: 100 μm) was used as the substrate sheet instead of the porous PE sheet.

Comparative example 1

A laminate was obtained in the same manner as in example 1, except that a pressure-sensitive adhesive sheet (thickness: 230 μm) comprising a pressure-sensitive adhesive layer (thickness: 20 μm) and a PE film (thickness: 210 μm) laminated was used as the substrate sheet instead of the porous PE sheet, and a varnish was applied to the pressure-sensitive adhesive layer.

Comparative example 2

A laminate was obtained in the same manner as in example 1, except that an epoxy glass sheet (thickness: 350 μm) was used as the substrate sheet instead of the porous PE sheet.

Comparative example 3

A laminate was obtained in the same manner as in example 1, except that a SUS sheet (thickness: 300 μm) was used as the substrate sheet instead of the porous PE sheet.

< Young's modulus >

Before the varnish was applied to the substrate sheet, the Young's modulus at 23 ℃ of the substrate sheet was measured on the surface to be coated with the varnish (the surface to be in contact with the metal-containing particle layer after the laminate was produced).

Young's modulus was measured by the method described above.

< evaluation test of transferability >

For evaluation test of transferability, TORAY ENGINEERING Co., Ltd, FC3000W was used.

First, Si mirror chips (5 mm in length: 5mm in width: 5mm in thickness: 200 μm) having one surface entirely plated with silver were pressed with a collet heated at 90 ℃ onto the metal particle-containing layer side of the laminates of examples and comparative examples on the one surface side, and a load was applied at 50N for 5 seconds.

Subsequently, the Si mirror chip was peeled from the laminate at a speed of 0.3 mm/sec using a collet to obtain a sample.

Then, from this sample, the area R1 of the whole one surface and the area R2 of the metal-containing particle layer transferred to the one surface were measured using VR-3000G2, and the ratio of the area R2 to the area R1 (R2/R1) was determined, and the value of the ratio expressed as a percentage was defined as the transfer ratio.

In the measurement using VR-3000G2, specifically, the sample is first placed on a stage so that the surface to which the metal-containing particle layer is transferred is on the upper side, and the sample is photographed at a magnification of 25 times with a low-magnification camera. Then, an area a1 of a portion protruding from the stage by more than half the thickness of the Si mirror chip (more than 100 μm from the stage) was measured, and the area a1 was set to the area R1. An area a2 of a portion protruding from the stage by not less than the sum of the "thickness of the Si mirror chip" and "half of the thickness of the metal-containing particle layer" (154 μm or more from the stage) was measured, and the area a2 was defined as the area R2.

The results are shown in table 1 below. The transfer ratios shown in table 1 below are values obtained by taking the arithmetic mean of the 3 measured values.

[ TABLE 1 ]

	Comparative example 1	Example 1	Example 2	Example 3	Example 4	Comparative example 2	Comparative example 3
								Young's modulus (GPa) of the substrate sheet	0.0001	0.3	0.5	0.9	3.4	21	190
Thickness of substrate sheet (μm)	230	300	300	250	300	350	300
								Transfer Rate (%)	23.1	96.9	99.5	95.2	99.8	79.6	84.7

As shown in table 1, the laminate of the example had a higher transfer rate than the laminate of the comparative example.

Therefore, according to the present invention, a laminate excellent in transferability can be provided.