KR102565488B1 - Adhesive sheet, dicing-tape-integrated adhesive sheet, and process for producing semiconductor device - Google Patents

Abstract

[Problem] To provide an adhesive sheet having high thermal conductivity and suppressing peeling after adhesion.
[Solution] An adhesive sheet comprising a silver-coated copper-based filler and a silver filler, wherein the silver-coated copper-based filler is flaky, has an average major diameter of 0.7 µm or more, and the silver filler has a primary particle size of 500 nm or less.

Description

Adhesive sheet, dicing tape integrated adhesive sheet, and manufacturing method of semiconductor device

The present invention relates to an adhesive sheet, a dicing tape integrated adhesive sheet, and a method for manufacturing a semiconductor device.

BACKGROUND OF THE INVENTION [0002] In recent years, the prevalence of power semiconductor devices that control or supply power has become remarkable. Since a current always flows in the power semiconductor device, the amount of heat generated is large. Therefore, it is preferable that the adhesive used for the power semiconductor device has high heat dissipation properties. In addition, it is not limited to adhesives for power semiconductor devices, and generally, adhesives used for semiconductor devices preferably have high heat dissipation properties.

Examples of adhesives having heat dissipation properties include those containing conductive fillers (for example, see Patent Literature 1).

Japanese Unexamined Patent Publication No. 2012-142370

In order to impart higher thermal conductivity, a method of highly filling the adhesive with a thermally conductive filler can be considered. However, when the content of the thermally conductive filler is increased, since the resin component is relatively decreased, the adhesive force is lowered. In addition, as the content of the thermally conductive filler increases, the elastic modulus increases and the stress relaxation property decreases. Therefore, peeling occurs due to the stress generated by the difference in linear expansion between the two objects to be bonded (for example, the difference in linear expansion between the semiconductor chip and the lead frame).

The present invention has been made in view of the above problems, and its object is to provide an adhesive sheet having high thermal conductivity and suppressing peeling after adhesion. Moreover, it is providing the dicing tape integrated adhesive sheet which has the said adhesive sheet. Moreover, it is providing the manufacturing method of the semiconductor device using the said dicing tape integrated adhesive sheet.

The present inventors studied adhesive sheets in order to solve the above conventional problems. As a result, it was discovered that adopting the following structure had high thermal conductivity and suppressed peeling after adhesion, and completed the present invention.

That is, the adhesive sheet according to the present invention,

A silver-coated copper-based filler;

Contains a silver filler,

The silver-coated copper-based filler is flaky and has an average major diameter of 0.7 μm or more, and the silver filler has a primary particle diameter of 500 nm or less.

Since the silver-coated copper-based filler transfers heat only through physical contact between the fillers, it is difficult to obtain high thermal conductivity due to the resistance of the contact portion. On the other hand, since a silver filler having a particle size of 500 nm or less is sintered at a relatively low temperature and chemically bonded to other metals, thermal conductivity higher than simple contact between fillers is obtained. However, since the aspect ratio is small in the silver filler alone, a good heat conduction path cannot be formed. Therefore, high thermal conductivity can be obtained by using together a covering filler having a large aspect ratio and a silver filler for connecting them. In addition, with a simple copper filler, since an oxide film is more easily formed on the surface than silver, it is difficult to take a good chemical bond with nanosilver, but good bonding is obtained by coating with silver.

Further, according to the above configuration, a silver filler having a primary particle diameter of 500 nm or less and a silver-coated copper-based filler having a flaky average major diameter of 0.7 µm or more are contained. That is, a silver filler and a silver-coated copper-based filler having a larger size than the silver filler are contained. Therefore, by heating, a metallic bond is formed between the silver filler and the silver-coated copper-based filler. As a result, high thermal conductivity is obtained even with a small content.

In addition, since the content of the filler (total content of the silver filler and the silver-coated copper-based filler) can be reduced, the chemical adhesive strength by the resin is improved. In addition, the silver filler forms an alloy with the metal of the adherend to chemically adhere. Therefore, the adhesive strength can be maintained high. Moreover, since content of a filler can be reduced, an elastic modulus can be made low. Since the elastic modulus is low, the stress relaxation property is excellent. As a result, peeling can be suppressed from occurring due to stress caused by a difference in linear expansion between the two objects to be bonded (for example, a difference in linear expansion between the semiconductor chip and the lead frame).

Moreover, compared with a silver filler, a silver-coated copper-type filler is excellent in low cost.

In the above configuration, it is preferable that the storage elastic modulus at 260°C after thermal curing is 10 to 700 MPa.

When the storage elastic modulus at 260°C after thermal curing is 700 MPa or less, the storage elastic modulus after thermal curing is relatively low. As a result, the stress relaxation property is more excellent. Further, when the storage elastic modulus at 260°C after thermal curing is 10 MPa or more, the adhesive strength is excellent.

In the above configuration, after bonding to a copper lead frame and heating at 200°C for 1 hour, the shear adhesion to the copper lead frame at 260°C is A, bonding to a silver-plated copper lead frame, and at 200°C When B is the shear adhesion to the silver-plated copper lead frame at 260° C. after heating for 1 hour, B/A is preferably 1.1 or more.

In ordinary epoxy adhesives, silver has lower adhesive strength than copper, and reliability problems may occur. However, when the B/A is 1.1 or more, good adhesion to silver is obtained, and thus the reliability of the silver-plated lead frame is improved.

In the above structure, it is preferable that the thermal conductivity in the thickness direction of the sheet after heating at 200°C for 1 hour is 3 W/m·K or more.

When the thermal conductivity in the thickness direction of the sheet after heating at 200°C for 1 hour is 3 W/m·K or more, the heat dissipation property is more excellent.

In the above configuration, when the weight of the silver-coated copper-based filler is C and the weight of the silver filler is D, the ratio C:D is preferably in the range of 9:1 to 5:5.

When the ratio C:D is in the range of 9:1 to 5:5, adhesion to silver and thermal conductivity become good. When there are too few silver fillers, the effect of improving adhesive force or thermal conductivity is not obtained. Conversely, since the film will become hard too much when there are too many silver fillers, sticking by low pressure is not performed.

In the above configuration, it is preferable that the coating amount of silver in the silver-coated copper-based filler is 5 to 30% by weight with respect to the weight of the entire silver-coated copper-based filler.

When the coating amount is 5% by weight or more, the surface of the copper filler can be satisfactorily coated, and good thermal conductivity is obtained by preventing oxidation of copper. On the other hand, if the coating amount is 30% by weight or less, the merit of using the coating filler is not obtained because the cost rises.

In the above structure, it is preferable that the specific surface area of the silver-coated copper-based filler is in the range of 0.5 to 1.5 m ² /g.

When the specific surface area of the silver-coated copper-based filler is 1.5 m ² /g or less, the adhesive sheet before thermal curing can be made more flexible. As a result, the adhesive force before thermal curing is more excellent. Moreover, since many contact points between fillers are obtained as the specific surface area of the said silver-coated copper filler is 0.5 m ^<2> /g or more, favorable thermal conductivity is obtained.

In the above structure, it is preferable that F/E is 10 or less when E is the number-converted average particle diameter of the covered filler and F is the volume-converted average particle diameter.

When the F/E is 10 or less, the particle size distribution of the filler becomes sharp, and thinning of the adhesive sheet by particle size control becomes possible. Here, the number-converted average particle size indicates a particle size at which the ratio of the cumulative number of particles is 50% in the cumulative particle distribution curve. The volume-converted average particle size indicates the particle size at which the cumulative volume ratio is 50% in the cumulative volume distribution curve. In addition, since the number-converted average particle diameter is based on the number of particles, both large and small particles can be counted as one, but since the volume-converted average particle diameter is based on volume, particles with a large particle diameter are counted as small particles. In comparison, the average particle diameter in terms of volume also increases. That is, the smaller the F/E, the sharper the particle size distribution is, and the larger the F/E, the broader the particle size distribution is.

In the above structure, it is preferable to contain an epoxy resin.

When an epoxy resin is contained, the object to be bonded can be favorably bonded by heating.

In the above configuration, it is preferable that the epoxy resin has a flexible skeleton.

When the epoxy resin has a flexible backbone, it is possible to further impart flexibility to the adhesive sheet after thermal curing.

In the above structure, it is preferable to contain a dispersing agent.

A silver filler having a primary particle size of 500 nm or less tends to aggregate. Therefore, when the dispersant is contained, the dispersibility of the filler in the resin is increased, the contact with the covering filler is increased, and the thermal conductivity is improved by forming a good pass.

In the above structure, it is preferable that the dispersing agent is an acrylic copolymer having a carboxylic acid group, an acid value of 20 or more, and an average weight molecular weight of 1000 or more.

When the average weight molecular weight of the dispersant is an acrylic copolymer of 1000 or more, thermal stability is excellent. Moreover, if the said dispersing agent has a carboxylic acid group and an acid value is 20 or more, aggregation of a silver filler can be suitably suppressed.

In addition, the dicing tape integrated adhesive sheet according to the present invention,

dicing tape;

With the adhesive sheet,

It is characterized in that the adhesive sheet is laminated on the dicing tape.

According to the said dicing tape integrated adhesive sheet, since it is integrated with a dicing tape, the process of bonding with a dicing tape can be omitted. In addition, since the adhesive sheet is provided, it has high thermal conductivity and peeling after adhesion is suppressed.

In addition, the manufacturing method of the semiconductor device according to the present invention,

a step of preparing the dicing tape-integrated adhesive sheet;

A step of attaching a semiconductor wafer to the dicing tape-integrated adhesive sheet;

dicing the semiconductor wafer together with the adhesive sheet to form a semiconductor chip with an adhesive sheet;

a step of picking up the semiconductor chip with the adhesive sheet from the dicing tape;

It is characterized by including a step of die-bonding the picked-up semiconductor chip with an adhesive sheet to an adherend.

According to the above configuration, since the adhesive sheet is used, the obtained semiconductor device can efficiently dissipate heat from the semiconductor chip. Further, since the adhesive sheet is used, in the obtained semiconductor device, peeling of the semiconductor chip and the adherend is suppressed.

1 is a schematic cross-sectional view of a dicing tape-integrated adhesive sheet according to the present embodiment.
2 is a cross-sectional schematic diagram for explaining a method of manufacturing a semiconductor device using a dicing tape-integrated adhesive sheet according to the present embodiment.
3 is a cross-sectional schematic diagram for explaining a method of manufacturing a semiconductor device using a dicing tape-integrated adhesive sheet according to the present embodiment.
4 is a cross-sectional schematic diagram for explaining a method of manufacturing a semiconductor device using the dicing tape-integrated adhesive sheet according to the present embodiment.
5 is a cross-sectional schematic diagram for explaining a method of manufacturing a semiconductor device using the dicing tape-integrated adhesive sheet according to the present embodiment.

The adhesive sheet and the dicing tape-integrated adhesive sheet according to the present embodiment will be described below. As for the adhesive sheet according to the present embodiment, among the dicing tape-integrated adhesive sheets described below, those in a state where no dicing tape is bonded are exemplified. Therefore, below, the dicing tape-integrated adhesive sheet will be described, and the adhesive sheet will be described therein. In addition, below, the case where an adhesive sheet is a die-bonding film is demonstrated. 1 is a schematic cross-sectional view of a dicing tape-integrated adhesive sheet according to the present embodiment.

(Dicing Tape Integrated Adhesive Sheet)

As shown in FIG. 1 , the dicing tape-integrated adhesive sheet 10 has a structure in which an adhesive sheet 30 as a die bond film is laminated on a dicing tape 20 . The dicing tape 20 is formed by laminating an adhesive layer 24 on a substrate 22 . The adhesive sheet 30 is provided on the pressure-sensitive adhesive layer 24 .

On the other hand, in this embodiment, the case where the adhesive sheet 30 is laminated on a part of the surface of the pressure-sensitive adhesive layer 24 will be described. More specifically, the case where the adhesive sheet 30 is formed only in the portion 26 of the pressure-sensitive adhesive layer 24 corresponding to the bonding portion of the semiconductor wafer will be described. However, the present invention is not limited to this example. The adhesive sheet of the present invention may be laminated on the entire surface of the pressure-sensitive adhesive layer. Moreover, the structure laminated|stacked on the part larger than the part corresponding to the sticking part of a semiconductor wafer, and smaller than the whole surface of an adhesive layer may be sufficient. On the other hand, the surface of the adhesive sheet (surface on the side to be affixed to the semiconductor wafer) may be protected with a separator or the like until it is affixed to the semiconductor wafer.

(adhesive sheet)

The adhesive sheet 30 contains a silver-coated copper-based filler and a silver filler. The silver-coated copper-based filler is flaky and has an average major diameter of 0.7 μm or more, and the silver filler has a primary particle diameter of 500 nm or less.

Since the silver-coated copper-based filler transfers heat only through physical contact between the fillers, it is difficult to obtain high thermal conductivity due to the resistance of the contact portion. On the other hand, since a silver filler having a particle size of 500 nm or less is sintered at a relatively low temperature and chemically bonded to other metals, thermal conductivity higher than simple contact between fillers is obtained. However, since the aspect ratio is small in the silver filler alone, a good heat conduction path cannot be formed. According to the adhesive sheet 30, high thermal conductivity can be obtained by using together the covering filler with a large aspect ratio, and the silver filler for connecting it. In addition, with a simple copper filler, since an oxide film is more easily formed on the surface than silver, it is difficult to take a good chemical bond with nanosilver, but good bonding is obtained by coating with silver.

Further, according to the adhesive sheet 30, a silver filler having a primary particle size of 500 nm or less and a silver-coated copper-based filler having a flaky shape and an average major diameter of 0.7 μm or more are contained. That is, a silver filler and a silver-coated copper-based filler having a larger size than the silver filler are contained. Therefore, by heating, a metallic bond is formed between the silver filler and the silver-coated copper-based filler. As a result, high thermal conductivity is obtained even with a small content.

In addition, since the content of the filler (total content of the silver filler and the silver-coated copper-based filler) can be reduced, the chemical adhesive strength by the resin is improved. In addition, the silver filler forms an alloy with the metal of the adherend to chemically adhere. Therefore, the adhesive strength can be maintained high. Moreover, since content of a filler can be reduced, an elastic modulus can be made low. Since the elastic modulus is low, the stress relaxation property is excellent. As a result, peeling can be suppressed from occurring due to stress caused by a difference in linear expansion between the two objects to be bonded (for example, a difference in linear expansion between the semiconductor chip and the lead frame).

Moreover, compared with a silver filler, a silver-coated copper-type filler is excellent in low cost.

The average major axis of the silver-coated copper-based filler is preferably 0.7 μm or more, and more preferably 1 μm or more. In addition, the average major axis of the silver-coated copper-based filler is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of reducing the thickness of the adhesive film.

The aspect ratio of the silver-coated copper filler is preferably 1.5 or more, more preferably 3 or more. When it is 2 or more, surface contact between silver-coated copper fillers is easy, and a conductive path is formed easily. Although the aspect ratio is preferably larger, it is, for example, 100 or less and 50 or less.

The aspect ratio of the silver-coated copper filler is the ratio of the average major axis to the average thickness (average major axis/average thickness).

In the present specification, the average major axis of the silver-coated copper-based filler is obtained by observing the cross section of the adhesive sheet 30 with a scanning electron microscope (SEM) and measuring the major axis of 100 randomly selected silver-coated copper-based fillers. is the average value obtained.

The average thickness of the silver-coated copper-based filler is an average value obtained by observing a cross section of the adhesive sheet 30 with a scanning electron microscope (SEM) and measuring the thickness of 100 randomly selected silver-coated copper-based fillers. .

The primary particle diameter of the silver filler is preferably 400 nm or less, and more preferably 300 nm or less. The primary particle diameter of the silver filler is preferably smaller, but from the viewpoint of easy aggregation of the small filler, it is preferably 10 nm or more, and more preferably 100 μm or less.

The primary particle size of the silver filler refers to the particle size of each silver filler in a non-aggregated state, and is measured by the following method. That is, it is an average value obtained by observing the cross section of the adhesive sheet 30 with a scanning electron microscope (SEM) and measuring the particle diameters of 100 randomly selected silver fillers.

When the weight of the silver-coated copper-based filler is C and the weight of the silver filler is D, the ratio C:D is preferably in the range of 9:1 to 5:5, more preferably 8:2 to 6:4. When the ratio C:D is in the range of 9:1 to 5:5, good thermal conductivity and adhesion to silver are obtained.

The coating amount of silver in the silver-coated copper-based filler is preferably 5 to 30% by weight, more preferably 7 to 20% by weight with respect to the total weight of the silver-coated copper-based filler. When the coating amount is 5% by weight or more, the surface of the copper filler can be uniformly coated. On the other hand, if the coating amount is 30% by weight or less, cost increase due to excessive coating can be suppressed.

The specific surface area of the silver-coated copper-based filler is preferably in the range of 0.5 to 1.5 m ² /g, more preferably in the range of 0.7 to 1.3 m ² /g. When the specific surface area of the silver-coated copper-based filler is 1.5 m ² /g or less, the adhesive sheet before thermal curing can be made more flexible. As a result, the adhesive force before thermal curing is more excellent. Moreover, when the specific surface area of the said silver-coated copper filler is 0.5 m ^<2> /g or more, the contact area of fillers increases and favorable thermal conductivity is obtained. The specific surface area of the silver-coated copper-based filler is determined by the BET method.

It is preferable that F/E is 10 or less, more preferably 5 or less, when E is the number converted average particle diameter of the said coated filler, and F is the volume converted average particle diameter. When the F/E is 10 or less, the particle size distribution of the filler becomes sharp, and thinning of the adhesive sheet is possible by controlling the particle size. The F/E is preferably smaller, but can be set to, for example, 1 or more from the viewpoint that when the particle size distribution is too sharp, the fillability of the filler is lowered and the thermal conductivity is lowered. The number-converted average particle diameter E and the volume-converted average particle diameter F of the silver filler are determined by a laser diffraction particle size distribution measurement method.

The adhesive sheet 30 preferably contains a dispersant. A silver filler having a primary particle size of 500 nm or less tends to aggregate. Therefore, when the dispersing agent is contained, the silver filler is suitably dispersed and the thermal conductivity of the adhesive is improved.

As said dispersing agent, it is roughly divided into what has both what has an acid value and what has an amine value, for example. As a dispersant having an acid value, representative examples include DISPERBYK-102, DISPERBYK-110, DISPERBYK-111, DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, BYK-P104, BYK-P104S, BYK-P105, BYK-220S, and EFKA. 5010, EFKA 5065, EFKA 5066, EFKA 5070, SOLSPERSE 3000, SOLSPERSE 16000, SOLSPERSE 17000, SOLSPERSE 18000, SOLSPERSE 21000, SOLSPERSE 27000, SOLSPERSE 28000, SOLSPERSE 36000, SOLS PERSE 36600, SOLSPERSE 38500, SOLSPERSE 39000, SOLSPERSE 41000, AJISPER PN -411, Ajisper PA-111, ARUFON UC-3000, UC-3080, UC-3510, UC-5080, UC-5022, etc. As a dispersant having an amine value, representative examples include DISPERBYK-108, DISPERBYK-109, DISPERBYK-112, DISPERBYK-116, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-167, DISPERBYK -168, DISPERBYK-182, DISPERBYK-183, DISPERBYK-184, DISPERBYK-185, DISPERBYK-2000, DISPERBYK-2008, DISPERBYK-2009, DISPERBYK-2050, DISPERBYK-2150, DISPERBYK-2155, DISPERBYK-2163, DISPERBYK-2164 , BYK-9077, EFKA 4046, EFKA 4047, EFKA 4015, EFKA 4020, EFKA 4050, EFKA 4055, EFKA 4060, EFKA 4080, EFKA 4300, EFKA 4330, EFKA 4400, EFKA 4401, EFKA 4402, EFKA 4403, EFKA 4800, SOLSPERSE 20000, etc. As a dispersant having both an acid value and an amine value, typical examples include ANTI-TERRA-U, ANTI-TERRA-205, DISPERBYK-101, DISPERBYK-106, DISPERBYK-130, DISPERBYK-140, DISPERBYK-142, DISPERBYK-145, DISPERBYK -180, DISPERBYK-2001, DISPERBYK-2020, DISPERBYK-2025, DISPERBYK-2070, BYK-9076, EFKA 4008, EFKA 4009, EFKA 4010, EFKA 4406, EFKA 5044, EFKA 5244, EFKA 5054, EFKA 5 055, EFKA 5063, EFKA 5064 SOLSPERSE 13240 SOLSPERSE 13940 SOLSPERSE 24000SC SOLSPERSE 24000GR SOLSPERSE 26000 SOLSPERSE 31845 SOLSPERSE 32000 SOLSPERSE 32500 SOLSPERSE 32550 SOLSPERSE 34750 LSPERSE 35100, SOLSPERSE 35200, SOLSPERSE 37500, Ajisper PB821, Ajisper PB822, Ajisper PB881, etc. Especially, it is preferable that it is an acrylic copolymer which has a carboxylic acid group, has an acid value of 20 or more, and has an average weight molecular weight of 1000 or more. When the average weight molecular weight of the dispersant is an acrylic copolymer of 1000 or more, thermal stability is excellent. Moreover, if the said dispersing agent has a carboxylic acid group and an acid value is 20 or more, aggregation of a silver filler can be suitably suppressed.

On the other hand, the weight average molecular weight of the dispersing agent is a value calculated by measuring by GPC (gel permeation chromatography) and calculated by polystyrene conversion.

The adhesive sheet 30 preferably contains a curable resin such as a thermosetting resin. Thereby, thermal stability can be improved.

Examples of curable resins include phenol resins, amino resins, unsaturated polyester resins, epoxy resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. In particular, an epoxy resin containing less ionic impurities or the like that corrode semiconductor elements is preferable. Moreover, as a hardening|curing agent of an epoxy resin, a phenol resin is preferable. When a thermoplastic resin such as an epoxy resin is contained, the object to be bonded can be favorably bonded by heating.

The epoxy resin is not particularly limited, and examples thereof include bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, and phenol. Bifunctional epoxy resins or multifunctional epoxy resins such as novolac type, orthocresol novolak type, trishydroxyphenylmethane type, tetraphenylolethane type, etc., or hydantoin type, trisglycidyl isocyanurate type, or Epoxy resins such as glycidylamine type are used. Among these epoxy resins, bisphenol A type epoxy resins are particularly preferred. This is because these epoxy resins are rich in reactivity with a phenol resin as a curing agent and have excellent heat resistance and the like.

Also, the epoxy resin preferably has a flexible skeleton. When the epoxy resin has a flexible backbone, it is possible to further impart flexibility to the adhesive sheet after thermal curing. Examples of the plastic skeleton include non-aromatic skeletons, and examples thereof include long-chain aliphatic skeletons, polyether skeletons, polyester skeletons, and polysulfone skeletons. Among them, a polyether skeleton is preferred from the viewpoints of thermal stability and productivity. Among the above epoxy resins, those which are bisphenol A type epoxy resins and have a flexible skeleton are preferable.

Phenol resins act as a curing agent for epoxy resins, and include, for example, novolak-type resins such as phenol novolac resins, phenol aralkyl resins, cresol novolak resins, tert-butylphenol novolak resins, and nonylphenol novolac resins. Polyoxystyrene, such as a phenol resin, a resol-type phenol resin, and polyparaoxystyrene, etc. are mentioned. Among these phenol resins, phenol novolak resins and phenol aralkyl resins are particularly preferred. It is because connection reliability of a semiconductor device can be improved.

The blending ratio of the epoxy resin and the phenol resin is preferably blended such that the hydroxyl group in the phenol resin is 0.5 to 2.0 equivalent per 1 equivalent of the epoxy group in the epoxy resin component, for example. More suitable is 0.8 to 1.2 equivalents. That is, it is because when the mixing ratio of both is out of the above range, a sufficient curing reaction does not proceed and the properties of the cured product are easily deteriorated.

The adhesive sheet 30 preferably contains a curable resin that is liquid at 25°C. Thereby, favorable low-temperature sticking property is obtained. In this specification, the liquid phase at 25°C means that the viscosity is less than 5000 Pa·s at 25°C. On the other hand, solid at 25°C means that the viscosity is 5000 Pa·s or more at 25°C. On the other hand, the viscosity can be measured using model number HAAKE Roto VISCO1 manufactured by Thermo Scientific.

The adhesive sheet 30 preferably contains a thermoplastic resin. As the thermoplastic resin, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resins, polyamide resins such as 6-nylon and 6,6-nylon, phenoxy resins, acrylic resins, saturated polyester resins such as PET and PBT, polyamideimide resins, and fluororesins. Among these thermoplastic resins, acrylic resins having low ionic impurities and high heat resistance, which can ensure the reliability of semiconductor devices, are particularly preferred.

The acrylic resin is not particularly limited, and a polymer containing one or two or more esters of acrylic acid or methacrylic acid having a straight chain or branched alkyl group having 30 or less carbon atoms, particularly 4 to 18 carbon atoms (acrylic copolymer ) and the like. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, hexyl, heptyl, cyclohexyl, 2 -Ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, tetradecyl group, stearyl group, octadecyl group or dodecyl group Threading, etc. are mentioned.

In addition, as another monomer which forms a polymer (acrylic copolymer), it is not specifically limited, For example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, or crotonic acid Carboxyl group-containing monomers such as the like, acid anhydride monomers such as maleic anhydride or itaconic anhydride, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylate 6-hydroxyhexyl, (meth)acrylate 8-hydroxyoctyl, (meth)acrylate 10-hydroxydecyl, (meth)acrylate 12-hydroxylauryl or (4-hydroxymethylcyclohexyl) -hydroxyl group-containing monomers such as methyl acrylate, styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth) ) acrylate or a sulfonic acid group-containing monomer such as (meth)acryloyloxynaphthalenesulfonic acid or the like, or a phosphoric acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate or the like.

Among the acrylic resins, those having a weight average molecular weight of 100,000 or more are preferable, those of 300,000 to 3,000,000 are more preferable, and those of 500,000 to 2,000,000 are still more preferable. It is because it is excellent in adhesiveness and heat resistance if it is within the said numerical range. On the other hand, a weight average molecular weight is a value calculated by measuring by GPC (gel permeation chromatography) and calculated by polystyrene conversion.

The total content of the thermoplastic resin and the curable resin in the adhesive sheet 30 is preferably 5% by weight or more, more preferably 10% by weight or more. If it is 5% by weight or more, it is easy to maintain the shape as a film. The total content of the thermoplastic resin and the curable resin is preferably 70% by weight or less, and more preferably 60% by weight or less. If it is 70% by weight or less, conductivity can be suitably exhibited.

In the adhesive sheet 30, the weight of the thermoplastic resin/weight of the curable resin is preferably 50/50 to 10/90, and more preferably 40/60 to 15/85. When the ratio of the thermoplastic resin is greater than 50/50, the thermal stability tends to deteriorate. On the other hand, when the ratio of the thermoplastic resin is less than 10/90, film formation tends to become difficult.

The adhesive sheet 30 may contain fillers other than the silver-coated copper-based filler and the silver filler, depending on the application. The blending of the filler makes it possible to adjust the modulus of elasticity and the like. As said filler, an inorganic filler and an organic filler are mentioned. The inorganic filler is not particularly limited, and examples thereof include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, and boron nitride. , silica, etc. are mentioned. These can be used individually or in combination of 2 or more types.

The adhesive sheet 30 preferably contains a heat curing accelerator. Thereby, thermal curing of hardeners, such as an epoxy resin and a phenol resin, can be accelerated|stimulated.

Although it does not specifically limit as said thermosetting accelerator, For example, tetraphenylphosphonium tetraphenylborate (brand name; TPP-K), tetraphenylphosphonium dicyanamide (brand name; TPP-DCA), tetraphenylphosphonium tetra -P-triborate (trade name: TPP-MK), triphenylphosphine triphenylborane (trade name: TPP-S), and other phosphorus-boron-based hardening accelerators (all manufactured by Hokko Chemical Industry Co., Ltd.). .

Examples of the accelerator include 2-methylimidazole (trade name: 2MZ), 2-undecylimidazole (trade name: C11-Z), 2-heptadecylimidazole (trade name: C17Z), 1,2-dimethylimidazole (trade name; 1.2DMZ), 2-ethyl-4-methylimidazole (trade name; 2E4MZ), 2-phenylimidazole (trade name; 2PZ), 2-phenyl-4- Methylimidazole (trade name; 2P4MZ), 1-benzyl-2-methylimidazole (trade name; 1B2MZ), 1-benzyl-2-phenylimidazole (trade name; 1B2PZ), 1-cyanoethyl-2- Methylimidazole (trade name; 2MZ-CN), 1-cyanoethyl-2-undecylimidazole (trade name; C11Z-CN), 1-cyanoethyl-2-phenylimidazolium trimellitate (trade name 2PZCNS-PW), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (trade name; 2MZ-A), 2,4-diamino -6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine (trade name; C11Z-A), 2,4-diamino-6-[2'-ethyl-4' -Methylimidazolyl-(1')]-ethyl-s-triazine (trade name; 2E4MZ-A), 2,4-diamino-6-[2'-methylimidazolyl-(1')]- Ethyl-s-triazineisocyanuric acid adduct (trade name: 2MA-OK), 2-phenyl-4,5-dihydroxymethylimidazole (trade name: 2PHZ-PW), 2-phenyl-4- and imidazole-based curing accelerators such as methyl-5-hydroxymethylimidazole (trade name: 2P4MHZ-PW) (all manufactured by Shikoku Kasei Co., Ltd.).

Among them, tetraphenylphosphonium tetraphenyl borate (trade name: TPP-K) and tetraphenylphosphonium dicyanamide (trade name: TPP-DCA), which are excellent in potential, are preferable from the viewpoint of the preservation properties of the film adhesive. .

Further, from the viewpoint of the preservation properties of the film adhesive, 2-phenyl-4,5-dihydroxymethylimidazole (trade name: 2PHZ-PW) having excellent potential is preferable.

The content of the accelerator can be appropriately set, but is preferably 0.6 to 15 parts by weight, more preferably 0.8 to 10 parts by weight, based on 100 parts by weight of the material excluding the conductive particles from the constituent materials of the film adhesive.

The adhesive sheet 30 may appropriately contain a compounding agent generally used for film production, for example, a crosslinking agent, in addition to the above components.

The adhesive sheet 30 can be manufactured by a conventional method. For example, the adhesive sheet 30 is manufactured by preparing an adhesive composition solution containing the above components, applying the adhesive composition solution on a substrate separator to a predetermined thickness to form a coating film, and then drying the coating film. can do.

The solvent used for the adhesive composition solution is not particularly limited, but an organic solvent capable of uniformly dissolving, kneading or dispersing the above components is preferable. Examples thereof include ketone solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, acetone, methylethyl ketone, and cyclohexanone, toluene, and xylene. The application method is not particularly limited. As a method of solvent coating, a die coater, a gravure coater, a roll coater, a reverse coater, a comma coater, a pipe doctor coater, screen printing, etc. are mentioned, for example. Among them, a die coater is preferable in terms of high uniformity of coating thickness.

As the substrate separator, polyethylene terephthalate (PET), polyethylene, polypropylene, a plastic film or paper whose surface is coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent can be used. As a coating method of the adhesive composition solution, roll coating, screen coating, gravure coating, etc. are mentioned, for example. In addition, drying conditions of the coating film are not particularly limited, and, for example, a drying temperature of 70 to 160°C and a drying time of 1 to 5 minutes can be performed.

As a method of manufacturing the adhesive sheet 30, a method of manufacturing the adhesive sheet 30 by mixing the above components in a mixer and press-molding the resulting mixture, for example, is also suitable. As a mixer, a planetary mixer etc. are mentioned.

The adhesive sheet 30 preferably has a storage modulus of 10 to 700 MPa at 260° C. after thermal curing, more preferably 50 to 350 MPa. When the storage elastic modulus at 260°C after thermal curing is 700 MPa or less, the storage elastic modulus after thermal curing is relatively low. As a result, the stress relaxation property is more excellent. Further, when the storage elastic modulus at 260°C after thermal curing is 10 MPa or more, the adhesive strength is excellent.

On the other hand, in this specification, after thermal curing means the thing after heating at 120 degreeC for 1 hour, and further heating at 175 degreeC for 1 hour after that.

The adhesive sheet 30 is bonded to a copper lead frame, heated at 200° C. for 1 hour, and has a shear adhesion to the copper lead frame at 260° C. A, adhered to a silver-plated copper lead frame, 200 When B is the shear adhesion to the silver-plated copper lead frame at 260° C. after heating at ° C. for 1 hour, B / A is preferably 1.1 or more, more preferably 1.2 or more. When the B/A is 1.1 or more, good reliability can be obtained for silver. Further, the larger the B/A is, the more preferable it is, but is, for example, 10 or less.

Said B/A is controllable by the addition amount and particle size of a silver filler, for example.

The shear adhesive strength A is preferably 0.1 to 30 MPa, more preferably 0.5 to 20 MPa, from the viewpoint of securing the adhesive strength to copper.

The shear adhesive strength B is preferably 0.3 to 30 MPa, more preferably 0.7 to 25 MPa, from the viewpoint of securing the adhesive strength to silver.

The thermal conductivity of the adhesive sheet 30 in the sheet thickness direction after being heated at 200°C for 1 hour is preferably 3 W/m·K or more, more preferably 4 W/m·K or more. When the thermal conductivity in the thickness direction of the sheet after heating at 200°C for 1 hour is 3 W/m·K or more, the heat dissipation property is more excellent.

The thermal conductivity can be controlled by the total content or content ratio of the silver-coated copper-based filler and the silver filler.

(dicing tape)

As shown in FIG. 1 , the dicing tape 20 includes a substrate 22 and an adhesive layer 24 disposed on the substrate 22 .

The base material 22 serves as the base of strength of the dicing tape 20, and preferably has ultraviolet light transmittance. Examples of the substrate 22 include low-density polyethylene, linear polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymerization polypropylene, block copolymerization polypropylene, homopolypropylene, polybutene, and polymethylpentene. of polyolefin, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, Polyesters such as polyurethane, polyethylene terephthalate, and polyethylene naphthalate, polycarbonate, polyimide, polyether ether ketone, polyimide, polyetherimide, polyamide, wholly aromatic polyamide, polyphenylsulfide, Aramid (paper), glass, glass cloth, fluororesin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, metal (foil), paper, etc. are mentioned.

The surface of the substrate 22 is chemically treated with conventional surface treatment such as chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, ionizing radiation treatment, etc. Alternatively, coating treatment with a physical treatment or a primer (for example, an adhesive substance described later) can be performed.

The thickness of the substrate 22 is not particularly limited and can be appropriately determined, but is generally about 5 to 200 μm.

The pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer 24 is not particularly limited, and common pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives and rubber-based pressure-sensitive adhesives can be used, for example. As the pressure-sensitive adhesive, an acrylic adhesive containing an acrylic polymer as a base polymer is preferable from the viewpoint of cleanability with organic solvents such as ultrapure water and alcohol for electronic parts that do not like contamination of semiconductor wafers and glass.

Examples of the acrylic polymer include (meth)acrylic acid alkyl esters (e.g., methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl Ester, isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl esters, hexadecyl esters, octadecyl esters and eicosyl esters of alkyl groups having 1 to 30 carbon atoms, particularly linear or branched chain alkyl esters having 4 to 18 carbon atoms, etc.) and (meth)acrylic acid cycloalkyl esters (for example, , cyclopentyl ester, cyclohexyl ester, etc.) using one or two or more of them as monomer components; and the like. Meanwhile, (meth)acrylic acid ester refers to acrylic acid ester and/or methacrylic acid ester, and (meth) in the present invention has the same meaning.

The acrylic polymer may contain units corresponding to other monomer components copolymerizable with the alkyl (meth)acrylic acid ester or cycloalkyl ester, as necessary, for the purpose of modification such as cohesive force and heat resistance. Examples of such a monomer component include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, hydroxyl group-containing monomers such as 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate; Styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl(meth)acrylate, (meth)acryloyloxynaphthalene sulfonic acid group-containing monomers such as sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; Acrylamide, acrylonitrile, etc. are mentioned. These copolymerizable monomer components can be used singly or in combination of two or more. As for the usage-amount of these copolymerizable monomers, 40 weight% or less of all monomer components is preferable.

In addition, the acrylic polymer may also contain a multifunctional monomer or the like as a monomer component for copolymerization, if necessary, for crosslinking. As such a multifunctional monomer, for example, hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, (meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, urethane (meth)acrylate, etc. are mentioned. One type or two or more types of these polyfunctional monomers can also be used. The amount of the polyfunctional monomer used is preferably 30% by weight or less of all monomer components in terms of adhesive properties and the like.

An acrylic polymer is obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. Polymerization may be carried out by any method such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization. From the standpoint of preventing contamination of a clean adherend, etc., a low molecular weight substance content is preferably small. From this point, the number average molecular weight of the acrylic polymer is preferably 300,000 or more, more preferably about 400,000 to 3,000,000.

In addition, an external crosslinking agent may be appropriately employed for the pressure-sensitive adhesive in order to increase the number average molecular weight of the base polymer, such as an acrylic polymer. As a specific means of the external crosslinking method, a method of reacting by adding a so-called crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound, or a melamine-based crosslinking agent is exemplified. When an external crosslinking agent is used, its amount is appropriately determined depending on the balance with the base polymer to be crosslinked and furthermore depending on the intended use as an adhesive. Generally, about 5 parts by weight or less, more preferably 0.1 to 5 parts by weight, is blended with respect to 100 parts by weight of the base polymer. Furthermore, you may use additives, such as conventionally well-known various tackifiers and anti-aging agents, other than the said component for an adhesive, as needed.

The pressure-sensitive adhesive layer 24 can be formed of a radiation curable pressure-sensitive adhesive. Radiation-curable pressure-sensitive adhesives can easily reduce their adhesive strength by increasing the degree of crosslinking by irradiation with radiation such as ultraviolet rays.

By irradiating only the portion 26 of the pressure-sensitive adhesive layer 24 shown in FIG. 1 corresponding to the workpiece sticking portion, a difference in adhesive strength from other portions can be made. In this case, the portion formed of the uncured radiation-curable pressure-sensitive adhesive is adhered to the adhesive sheet 30, and holding force during dicing can be secured. In addition, the wafer ring can be fixed to a portion formed of an uncured radiation curable pressure-sensitive adhesive.

As the radiation-curable pressure-sensitive adhesive, those having a radiation-curable functional group such as a carbon-carbon double bond and exhibiting adhesiveness can be used without particular limitation. Examples of radiation-curable pressure-sensitive adhesives include additive-type radiation-curable pressure-sensitive adhesives in which a radiation-curable monomer component or oligomer component is blended with general pressure-sensitive adhesives such as the acrylic pressure-sensitive adhesive and rubber-based pressure-sensitive adhesive.

As a radiation curable monomer component to be blended, for example, urethane oligomer, urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethanetetra(meth)acrylate , pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4- Butanedioldi(meth)acrylate etc. are mentioned. In addition, the radiation curable oligomer component includes various oligomers such as urethane, polyether, polyester, polycarbonate, and polybutadiene, and it is suitable that the molecular weight is in the range of about 100 to 30,000. do. The blending amount of the radiation-curable monomer component or oligomer component can be appropriately determined according to the type of the pressure-sensitive adhesive layer, and the amount capable of reducing the adhesive force of the pressure-sensitive adhesive layer. Generally, it is, for example, 5 to 500 parts by weight, preferably about 40 to 150 parts by weight, based on 100 parts by weight of a base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

Further, as the radiation curable pressure-sensitive adhesive, in addition to the above-described addition-type radiation-curable pressure-sensitive adhesive, an intrinsic radiation-curable pressure-sensitive adhesive using a base polymer having a carbon-carbon double bond in the polymer side chain or main chain or at the main chain terminal may be mentioned. Intrinsic radiation-curable pressure-sensitive adhesives do not need to contain or do not contain a low molecular weight oligomer component, etc., so that the oligomer component does not move through the pressure-sensitive adhesive over time, and the pressure-sensitive adhesive layer has a stable layer structure. It is preferable because it can form.

As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness may be used without particular limitation. As such a base polymer, it is preferable to use an acrylic polymer as a basic skeleton. As a basic frame|skeleton of an acrylic polymer, the acrylic polymer illustrated above is mentioned.

A method for introducing a carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods may be employed. However, introducing a carbon-carbon double bond into a side chain of a polymer facilitates molecular design. For example, after copolymerizing a monomer having a functional group with an acrylic polymer in advance, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is condensed while maintaining the radiation curability of the carbon-carbon double bond. Or the method of making an addition reaction is mentioned.

Examples of combinations of these functional groups include a carboxylic acid group and an epoxy group, a carboxylic acid group and an aziridinyl group, a hydroxyl group and an isocyanate group. Among the combinations of these functional groups, a combination of a hydroxyl group and an isocyanate group is suitable because of the ease of tracking the reaction. In addition, as long as the combination of these functional groups produces an acrylic polymer having a carbon-carbon double bond, the functional group may be present on either side of the acrylic polymer and the compound, but in the above preferred combination, the acrylic polymer It has a hydroxyl group and is suitable if the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl-α. , α-dimethylbenzyl isocyanate, and the like. In addition, as an acrylic polymer, what copolymerized the hydroxyl group containing monomer of the above example, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. ether type compound is used do.

In the intrinsic radiation-curable pressure-sensitive adhesive, the base polymer (particularly, an acrylic polymer) having a carbon-carbon double bond can be used alone, but the radiation-curable monomer component or oligomer component may be blended to the extent that the properties are not deteriorated. there is. The radiation curable oligomer component and the like are usually within the range of 30 parts by weight, preferably 0 to 10 parts by weight, based on 100 parts by weight of the base polymer.

The radiation-curable pressure-sensitive adhesive contains a photopolymerization initiator when cured by ultraviolet rays or the like. Examples of the photopolymerization initiator include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, and 2-methyl- α-ketol compounds such as 2-hydroxypropiophenone and 1-hydroxycyclohexylphenyl ketone; Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-mo acetophenone-based compounds such as polynopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; ketal-based compounds such as benzyl dimethyl ketal; Aromatic sulfonyl chloride type compounds, such as 2-naphthalene sulfonyl chloride; photoactive oxime-based compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; Thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethyl thioxanthone-based compounds such as thioxanthone and 2,4-diisopropyl thioxanthone; camphorquinone; halogenated ketones; acyl phosphine oxide; Acyl phosphonate etc. are mentioned. The blending amount of the photopolymerization initiator is, for example, about 0.05 to 20 parts by weight with respect to 100 parts by weight of a base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

Further, examples of the radiation-curable pressure-sensitive adhesive include an addition-polymerizable compound having two or more unsaturated bonds, a photopolymerizable compound such as an alkoxysilane having an epoxy group, and carbonyl disclosed in Japanese Patent Laid-Open No. 60-196956. and rubber-based pressure-sensitive adhesives and acrylic-based pressure-sensitive adhesives containing photopolymerization initiators such as chemical compounds, organic sulfur compounds, peroxides, amines, and onium salt-based compounds.

In the radiation-curable pressure-sensitive adhesive layer 24, if necessary, a compound that is colored by irradiation with radiation may be contained. By making the pressure-sensitive adhesive layer 24 contain a compound to be colored by irradiation with radiation, only the portion irradiated with radiation can be colored. The compound colored by irradiation is colorless or light-colored before irradiation with radiation, but is a compound that becomes colored by irradiation with radiation, and examples thereof include leuco dyes. The use ratio of the compound colored by irradiation with radiation can be set appropriately.

The thickness of the pressure-sensitive adhesive layer 24 is not particularly limited, but is preferably about 1 to 50 μm from the viewpoints of chip cutting surface crack prevention and adhesive sheet 30 fixing compatibility. Preferably it is 2-30 micrometers, and 5-25 micrometers are more preferable.

The dicing tape-integrated adhesive sheet 10 can be manufactured by a conventional method. For example, the dicing tape integrated adhesive sheet 10 can be manufactured by bonding the adhesive layer 24 of the dicing tape 20 and the adhesive sheet 30 together.

(Method of manufacturing semiconductor device)

The method for manufacturing a semiconductor device according to the present embodiment includes:

A step of preparing a dicing tape integrated adhesive sheet;

A step of attaching a semiconductor wafer to the dicing tape-integrated adhesive sheet;

dicing the semiconductor wafer together with the adhesive sheet to form a semiconductor chip with an adhesive sheet;

a step of picking up the semiconductor chip with the adhesive sheet from the dicing tape;

It includes at least a step of die-bonding the picked-up semiconductor chip with adhesive sheet to an adherend.

Hereinafter, a semiconductor device manufacturing method according to the present embodiment will be described with reference to FIGS. 2 to 5 . 2 to 5 are cross-sectional schematic diagrams for explaining a method for manufacturing a semiconductor device using the dicing tape-integrated adhesive sheet according to the present embodiment.

First, the dicing tape-integrated adhesive sheet 10 is prepared.

Next, as shown in FIG. 2 , the semiconductor wafer 40 is affixed to the dicing tape-integrated adhesive sheet 10 . As the semiconductor wafer 40, a silicon wafer, a silicon carbide wafer, a compound semiconductor wafer, etc. are mentioned. As a compound semiconductor wafer, a gallium nitride wafer etc. are mentioned.

As a sticking method, the method of pressing with a pressing means, such as a pressure bonding roll, etc. are mentioned, for example. As the sticking pressure, it is preferable to be in the range of 0.05 to 10 MPa. In addition, although the sticking temperature is not specifically limited, It is preferable to be in the range of 23-90 degreeC, for example.

Next, as shown in FIG. 3 , the semiconductor wafer 40 is diced. That is, the semiconductor wafer 40 is cut into a predetermined size together with the adhesive sheet 30 to form the semiconductor chip 50 with the adhesive sheet 30 . Dicing is performed according to a conventional method. In addition, in this process, the cutting method called full-cut etc. which perform incision up to the dicing tape integrated adhesive sheet 10 can be employ|adopted, for example. It does not specifically limit as a dicing apparatus used in this process, A conventionally well-known thing can be used. Since the semiconductor wafer 40 is fixed by the dicing tape-integrated adhesive sheet 10, chip cracking and chip flying can be suppressed, and damage to the semiconductor wafer 40 can also be suppressed.

Next, as shown in FIG. 4 , the semiconductor chip 50 with the adhesive sheet 30 is picked up from the dicing tape 20 . The pick-up method is not particularly limited, and conventionally known various methods can be employed. For example, the method of pushing up each semiconductor chip 50 with a needle from the side of the dicing tape 20, and picking up the pushed semiconductor chip 5 with a pick-up device etc. are mentioned.

As pick-up conditions, from the viewpoint of preventing chipping, the needle pushing-up speed is preferably 5 to 100 mm/sec, and more preferably 5 to 10 mm/sec.

When the pressure-sensitive adhesive layer 24 is of an ultraviolet curing type, pick-up may be performed after irradiating the pressure-sensitive adhesive layer 24 with ultraviolet rays. As a result, the adhesive strength of the pressure-sensitive adhesive layer 24 to the adhesive sheet 30 decreases, and the separation of the semiconductor chip 50 becomes easy. As a result, pick-up becomes possible without damaging the semiconductor chip 50 . Conditions, such as irradiation intensity at the time of ultraviolet irradiation and irradiation time, are not specifically limited, What is necessary is just to set suitably as needed.

Next, as shown in FIG. 5 , the semiconductor chip 50 picked up is die-bonded to the adherend 60 with the adhesive sheet 30 interposed therebetween. Examples of the adherend 60 include a lead frame, a TAB film, a substrate, or a separately produced semiconductor chip. The adherend 60 may be, for example, a deformable adherend that is easily deformed or a non-deformable adherend that is difficult to deform (eg, a semiconductor wafer).

As the substrate, a conventionally known substrate can be used. As the lead frame, a metal lead frame such as a Cu lead frame or a 42 alloy lead frame, or an organic substrate made of glass epoxy, BT (bismaleimide-triazine), polyimide or the like can be used. However, the present invention is not limited thereto, and a circuit board capable of being electrically connected to the semiconductor chip by mounting the semiconductor chip is also included.

As die bonding conditions, a pressure of 0.01 MPa to 5 MPa is preferable. In addition, the temperature at the time of die bonding is not particularly limited, but is preferably within a range of 23 to 200°C, for example.

Then, by heating the adherend 60 with the semiconductor chip 50, the adhesive sheet 30 is thermally cured, and the semiconductor chip 50 and the adherend 60 are fixed. At this time, it is preferable to sinter the silver filler in the adhesive sheet 30. The heating temperature can be performed at 80 to 200°C, preferably 100 to 175°C, and more preferably 100 to 140°C. In addition, the heating time can be performed at 0.1 to 24 hours, preferably 0.1 to 3 hours, and more preferably 0.2 to 1 hour. Heat curing may also be performed under pressurized conditions. As the pressurization conditions, the inside of the range of 1 to 20 kg/cm ² is preferable, and the inside of the range of 3 to 15 kg/cm ² is more preferable. Heat curing under pressure can be performed, for example, in a chamber filled with an inert gas. When heated under the above conditions, the adhesive sheet 30 is sufficiently thermally cured. As a result, occurrence of problems in the subsequent wire bonding process can be suppressed.

Next, a wire bonding step of electrically connecting the tip of the terminal portion (inner lead) of the adherend 60 and an electrode pad (not shown) on the semiconductor chip 50 with a bonding wire 70 is performed. As the bonding wire 70, a gold wire, an aluminum wire, or a copper wire is used, for example. The temperature at the time of wire bonding is performed within the range of 23 to 300°C, preferably 23 to 250°C. In addition, the heating time is several seconds to several minutes (for example, 1 second to 1 minute). Wiring is performed by combined use of vibration energy by ultrasonic waves and pressing energy by applied pressure in a state heated so as to be within the above temperature range.

Next, a sealing step of sealing the semiconductor chip 50 with the sealing resin 80 is performed as needed. This process is performed to protect the semiconductor chip 50 and the bonding wire 70 mounted on the adherend 60 . This step is performed by molding the resin for sealing with a mold. As the sealing resin 80, an epoxy resin is used, for example. The heating temperature during resin encapsulation is preferably 165°C or higher, more preferably 170°C or higher, and the heating temperature is preferably 185°C or lower, more preferably 180°C or lower. In this way, the encapsulating resin 80 is cured. On the other hand, in this sealing process, the method of embedding the semiconductor chip 50 in the sheet-shaped sealing sheet (for example, refer to Unexamined-Japanese-Patent No. 2013-7028) can also be employ|adopted. In addition to the molding of the encapsulating resin with a mold, a gel encapsulation type in which a silicone gel is introduced into a case type container may be used.

Next, if necessary, the encapsulated material may be additionally heated (post-curing step). In this way, the insufficiently cured sealing resin 80 can be completely cured in the sealing step. The heating temperature in this step varies depending on the type of encapsulating resin, but is within the range of, for example, 165 to 185°C, and the heating time is about 0.5 to 8 hours.

In the above embodiment, the case where the adhesive sheet of the present invention is the adhesive sheet 30 as a die-bonding film has been described, but the adhesive sheet of the present invention is not limited to this example. Examples of the adhesive sheet of the present invention include a film for flip chip type semiconductor back surface, an adhesive sheet between a semiconductor device and a heat sink, an adhesive sheet between packages of a PoP package (Package on Package), an adhesive sheet for LED chips, and the like. can

The film for flip chip type semiconductor back surface is a film that is affixed to the back surface (surface opposite to the flip chip connection surface) of a flip chip connected semiconductor chip.

In the case of the adhesive sheet flip chip type semiconductor back surface film of the present invention, after changing the composition and content to such an extent that it has a function as a flip chip type semiconductor back surface film, the same configuration as that of the adhesive sheet 30 as a die-bonding film can be employed. there is.

Example

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

The components used in the examples are described.

Silver-coated copper filler: 1200YP manufactured by Mitsui Metal Industry Co., Ltd. (flake shape, average major diameter: 2.3 μm, silver coating amount 20% by weight, specific surface area: 0.58 m ² /g, number conversion average particle diameter: 3.4 μm, volume conversion average particle diameter : 1.4μm)

Silver filler: Ag nano powder-2 (primary particle diameter: 60 nm) manufactured by DOWA Electronics Co., Ltd.

Acrylic resin: W-116.3 manufactured by Negami Kogyo Co., Ltd. (acid value: 7.8)

Phenolic resin: MEH-7800H manufactured by Maywa Kasei Co., Ltd.

Epoxy resin: EXA-4850 manufactured by DIC Corporation (including a non-aromatic skeleton as a flexible skeleton)

Curing accelerator: 2PHZ-PW manufactured by Shikoku Kasei Co., Ltd.

Dispersant: UC-3000 manufactured by Toa Synthetic Co., Ltd. (acrylic copolymer having a carboxylic acid group, acid value: 74, average weight molecular weight: 10000)

[Production of adhesive sheet]

According to the compounding ratios shown in Table 1, each component listed in Table 1 was dissolved in methyl ethyl ketone to prepare an adhesive composition solution having a concentration of 40 to 50% by weight.

The prepared adhesive composition solution was applied to a polyethylene terephthalate film having a thickness of 50 μm subjected to silicone release treatment, and then dried at 130° C. for 2 minutes to prepare an adhesive sheet having a thickness of 20 μm.

[Measurement of Shear Adhesion A to Copper Plate at 260°C]

The adhesive sheets of Examples and Comparative Examples were bonded to a silicon chip having a thickness of 500 µm and a size of 3 mm x 3 mm. Bonding conditions were the temperature at which the silicon chip sticks to the adhesive sheet (60 to 150°C), the speed of 10 mm/sec, and the pressure of 0.15 MPa. After that, the adhesive sheet was cut out to the same size as the silicon chip with a cutter knife. Next, the adhesive sheet was cured by heating at 120°C for 1 hour and further heating at 200°C for 1 hour in a nitrogen atmosphere. In the above manner, a chip for shear adhesion measurement was produced.

The adhesive side of this chip for measurement was bonded to a copper lead frame (base material: MF202) having a thickness of 0.2 μm at 150° C. for 1 second while holding at 1 MPa.

Using a shear tester (manufactured by Dage, Dage4000), shear adhesion between the adhesive sheet and the copper lead frame was measured. The conditions of the shear test were a measurement speed of 500 µm/s, a measurement gap of 100 µm, and a stage temperature of 260°C. The measurement was performed about 20 seconds after placing the sample on the measurement stage. The results are shown in Table 1.

[Measurement of Shear Adhesion B to Silver Plate at 260°C]

A chip for shear adhesion measurement was fabricated in the same manner as in the measurement of shear adhesion to the copper lead frame.

The adhesive side of this measurement chip was attached to a silver-plated copper lead frame (base material: MF202, silver plating thickness: 1 to 5 μm) having a thickness of 0.2 μm at 150° C. for 1 second while holding at 1 MPa.

Using a shear tester (manufactured by Dage, Dage4000), shear adhesion between the adhesive sheet and the silver-plated copper lead frame was measured. Conditions for the shear test were the same as for the measurement of the shear adhesive force to the copper lead frame. The results are shown in Table 1.

On the other hand, in Table 1, B/A was also described.

[Measurement of storage modulus at 260°C after thermal curing]

The adhesive sheets of Examples and Comparative Examples were laminated in a width of 10 mm × length of 30 mm × thickness of 400 μm. Next, the adhesive sheet was cured by heating at 120°C for 1 hour and further heating at 175°C for 1 hour in a nitrogen atmosphere.

Next, the storage elastic modulus was measured using a viscoelasticity measuring device RSA2 (manufactured by TA Instruments) under a nitrogen atmosphere under measurement conditions: a heating rate of 10°C/min, a frequency of 1 Hz, and a distance between chucks of 22.5 mm. The results are shown in Table 1.

(Measurement of thermal conductivity after heating at 200 ° C. for 1 hour)

First, the adhesive sheets of Examples and Comparative Examples were heat-cured by heating at 200°C for 1 hour. Thermal curing was performed in a nitrogen atmosphere.

Next, the thermal conductivity of these adhesive sheets after thermal curing was measured. The thermal conductivity was obtained from the following formula. The results are shown in Table 1.

(thermal conductivity) = (thermal diffusion coefficient) × (specific heat) × (specific gravity)

<Coefficient of Thermal Diffusion>.

First, the adhesive sheets of Examples and Comparative Examples were heated at 200°C for 1 hour in a nitrogen atmosphere. Next, it was cut into 20 mm squares, and the thermal diffusivity was measured using an i-phase mobile (manufactured by i-phase company).

<specific heat>

It was obtained by the measurement method according to the standard of JIS-7123 using DSC (manufactured by TA instrument, Q-2000).

<Proportion>

It measured by the Archimedes method using the electronic balance (Shimadzu Corporation make, AEL-200).

(Hygroscopic Reflow Reliability Test)

Each of the adhesive sheets of Examples and Comparative Examples was mounted on a semiconductor wafer. As the semiconductor wafer, a size of 8 inches and a back surface ground until the thickness reached 100 μm was used. Grinding conditions and bonding conditions are as follows.

<Wafer grinding conditions>

Grinding device: Disco, DGP-8760

Semiconductor wafer: 8 inch diameter (back ground from 750 μm to 100 μm thick)

<Combination conditions>

Attachment device: DR-3000II, manufactured by Nitto Seiki

Attachment Speedometer: 100mm/min

Attachment pressure: 0.3MPa

Stage temperature at the time of sticking: 100 ° C.

Next, the semiconductor wafer was diced to form a semiconductor chip. Dicing was performed so that it might become a 2 mm square chip size. The dicing conditions are as follows. On the other hand, in dicing, P2130G (manufactured by Nitto Denko Co., Ltd.) was used as a dicing tape.

<Dicing conditions>

Dicing device: Disco Co., Ltd., DFD-6361

Dicing speed: 30 mm/sec

Dicing blade: made by Disco

Z1: 205O-HEDD

Z2: 205O-HCBB

RPM: 40,000 rpm

Amount of cut into Z2 dicing tape: 20 μm

Cut method: Step cut/A mode

Chip size: 2mm each

Moreover, the semiconductor chip with an adhesive sheet was picked up from the base material side of the dicing tape by the push-up method by a needle. Pick-up conditions are as follows.

<Pick-up conditions>

Die bond device: manufactured by Shinkawa Co., Ltd., device name: SPA-300

Number of needles: 1

Needle push-up amount: 400 μm

Needle push-up speed: 5 mm/sec

Adsorption retention time: 80 ms

The picked-up semiconductor chip was die-bonded to a copper lead frame. The die bonding conditions were a stage temperature of 130°C, a load of 0.1 MPa, and a load time of 1 second. A copper lead frame (thickness: 0.2 μm, base material: MF202) was used.

Next, the Cu lead frame to which the semiconductor chip was die-bonded was subjected to heat treatment at 130° C. for 1 hour in a dryer, and then packaged with a sealing resin (Nitto Denko Co., Ltd. product, trade name: GE-7470LA). The sealing conditions were a molding temperature of 175°C and a molding time of 90 seconds. A post-curing step was further performed on the obtained semiconductor package. Specifically, the heating temperature was 175°C and the heating time was 1 hour. Thus, 10 semiconductor packages (length 5 mm × width 5 mm × thickness 0.7 mm) were produced.

Subsequently, the package was subjected to moisture absorption under the respective conditions of MSL1 and MSL2. In MSL1, the moisture absorption of the semiconductor package was performed under the condition of 85°C×85%RH×168 hours, and in the case of MSL2, the condition of 85°C×60%RH×168 hours. After that, the semiconductor package was placed in an IR reflow furnace set to a preheating temperature of 150±30° C., a preheating time of 90 seconds, a peak temperature of 260° C. or more, and a heating time at the peak temperature of 10 seconds. . Then, the semiconductor package was cut with a glass cutter, and the cross section was observed with an ultrasonic microscope to confirm the presence or absence of peeling at the boundary between each adhesive sheet and the substrate. Confirmation was performed on 9 semiconductor chips, ◎ when the peeling incidence rate was 50% or less under the MSL1 condition, ○ when the peeling incidence rate was 50% or less under the MSL2 condition, and 50% or higher peeling incidence rate in both cases. was evaluated as ×. The results are shown in Table 1.

10: dicing tape integrated adhesive sheet
20: dicing tape
22: registration
24: adhesive layer
30: adhesive sheet
40: semiconductor wafer
50: semiconductor chip
60: adherend
70: bonding wire
80: encapsulating resin

Claims (14)

A silver-coated copper-based filler;
Contains a silver filler,
The silver-coated copper-based filler is flaky and has an average major diameter of 0.7 μm or more and 10 μm or less,
The silver filler has a primary particle diameter of 10 nm or more and 500 nm or less,
An adhesive sheet characterized by having a storage modulus at 260°C after thermal curing of 10 to 700 MPa. delete According to claim 1,
Shear adhesion to the copper lead frame at 260°C after bonding to a copper lead frame and heating at 200°C for 1 hour, A, after bonding to a silver-plated copper lead frame and heating at 200°C for 1 hour , When B is the shear adhesion to the silver-plated copper lead frame at 260°C, B/A is 1.1 or more and 10 or less. According to claim 1,
An adhesive sheet characterized in that the thermal conductivity in the thickness direction of the sheet after heating at 200°C for 1 hour is 3 W/m·K or more. According to claim 1,
The adhesive sheet characterized in that, when the weight of the silver-coated copper-based filler is C and the weight of the silver filler is D, the ratio C:D is in the range of 9:1 to 5:5. According to claim 1,
The adhesive sheet characterized in that the coating amount of silver in the silver-coated copper-based filler is 5 to 30% by weight with respect to the total weight of the silver-coated copper-based filler. According to claim 1,
The adhesive sheet, characterized in that the specific surface area of the silver-coated copper-based filler is within the range of 0.5 to 1.5 m ² /g. According to claim 1,
The adhesive sheet characterized in that, when the number converted average particle diameter of the silver-coated copper-based filler is E and the volume converted average particle diameter is F, F/E is 1 or more and 10 or less. According to claim 1,
An adhesive sheet characterized by containing an epoxy resin. According to claim 9,
The adhesive sheet, characterized in that the epoxy resin has a flexible backbone. According to claim 1,
An adhesive sheet characterized by containing a dispersant. According to claim 11,
The adhesive sheet characterized in that the dispersant is an acrylic copolymer having a carboxylic acid group, an acid value of 20 or more, and an average weight molecular weight of 1000 or more. dicing tape;
An adhesive sheet according to any one of claims 1 and 3 to 12,
The dicing tape integrated adhesive sheet, characterized in that the adhesive sheet is laminated on the dicing tape. A step of preparing the dicing tape-integrated adhesive sheet according to claim 13;
A step of attaching a semiconductor wafer to the dicing tape-integrated adhesive sheet;
dicing the semiconductor wafer together with the adhesive sheet to form a semiconductor chip with an adhesive sheet;
a step of picking up the semiconductor chip with the adhesive sheet from the dicing tape;
A method of manufacturing a semiconductor device comprising a step of die-bonding the picked-up semiconductor chip with an adhesive sheet to an adherend.