JP2011198914A - Adhesive composition for semiconductor, adhesive sheet for semiconductor, and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a semiconductor having a high adhesiveness to an adhering part even in a case of having been subjected to a severe condition and a reflow process, an adhesive sheet for the semiconductor including an adhesive layer made of the adhesive composition, and a method of manufacturing the semiconductor using the same.SOLUTION: The adhesive composition for the semiconductor includes (A) an acrylic copolymer containing 3-10 wt.% structural unit derived from hydroxy-containing (meth)acrylic acid ester, and having a weight-average molecular weight of 100,000 to 1000,000, (B) an epoxy thermosetting resin, and (C) a thermosetting agent.

Description

  The present invention provides a step of die bonding a semiconductor element (semiconductor chip) to a die pad portion of an organic substrate or a lead frame or another semiconductor chip, and a semiconductor wafer is diced to form a semiconductor chip, and the semiconductor chip is die bonded to an adherend portion. The present invention relates to an adhesive composition for a semiconductor suitable for use in a process, an adhesive sheet for a semiconductor having an adhesive layer made of the adhesive composition, and a method for manufacturing a semiconductor device using the same.

  Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state. The semiconductor wafer is cut and separated (diced) into element pieces (semiconductor chips) and then transferred to the bonding process which is the next process. At this time, the semiconductor wafer is subjected to dicing, cleaning, drying, expanding, and pick-up processes in a state of being adhered to the adhesive sheet in advance, and then transferred to the next bonding process.

  Among these processes, various dicing / die bonding adhesive sheets having both a wafer fixing function and a die bonding function have been proposed in order to simplify the pickup process and the bonding process (for example, patents). Reference 1-5). The adhesive sheets disclosed in Patent Documents 1 to 4 enable so-called direct die bonding, and the application process of the adhesive agent for die bonding can be omitted. For example, by using the adhesive sheet, direct die bonding such as between an organic substrate and a chip, between a lead frame and a chip, and between a chip and a chip can be performed.

  By the way, the required physical properties of recent semiconductor devices have become very strict. For example, high package reliability is required under severe heat and humidity environments. In connecting electronic components, a surface mounting method (reflow) is performed in which the entire package is exposed to a high temperature equal to or higher than the solder melting point. In recent years, the mounting temperature has increased to about 260 ° C. due to the shift to lead-free solder. For this reason, the stress generated inside the semiconductor package is larger than before, and there is an increased possibility of problems such as peeling at the bonding interface and package cracks.

  JP-A-2003-55632 (Patent Document 6) discloses an adhesive tape having an adhesive layer composed of an adhesive component, a specific epoxy resin and a thermally activated latent curing agent. According to the adhesive tape, since the water absorption of the cured adhesive is low, package cracks during reflow can be prevented.

Japanese Patent Laid-Open No. 02-032181 Japanese Patent Laid-Open No. 08-239636 Japanese Patent Laid-Open No. 10-008001 JP 2000-017246 A International Publication No. WO2005 / 4216 Pamphlet JP 2003-55632 A

  An object of the present invention is to provide an adhesive composition for a semiconductor having high adhesion to an adherent part even under severe heat and humidity conditions and a reflow process, and an adhesive for a semiconductor having an adhesive layer made of the adhesive composition A sheet and a method of manufacturing a semiconductor device using the sheet are provided.

  The present inventors have intensively studied to solve the above problems. As a result, the above problem can be solved by using an acrylic copolymer containing a specific amount of a structural unit derived from a hydroxyl group-containing (meth) acrylic acid ester and having a weight average molecular weight in a specific range as an adhesive component. The headline and the present invention were completed.

The present invention relates to the following [1] to [3].
[1] (A) an acrylic copolymer having 3 to 10% by weight of a structural unit derived from a hydroxyl group-containing (meth) acrylic ester and having a weight average molecular weight of 100,000 to 1,000,000,
(B) An epoxy thermosetting resin, and (C) a semiconductor adhesive composition containing a thermosetting agent.

[2] An adhesive sheet for semiconductor, comprising an adhesive layer made of the adhesive composition for semiconductor according to [1], formed on a substrate.
[3] A semiconductor wafer is attached to the adhesive layer of the semiconductor adhesive sheet according to the above [2], the semiconductor wafer is diced into semiconductor chips, and the adhesive layer is fixedly left on the back surface of the semiconductor chip. A method for manufacturing a semiconductor device, comprising: a step of peeling from a base material and thermocompression bonding the semiconductor chip to an adherend via an adhesive layer.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition for semiconductors which has the high adhesiveness with respect to a to-be-adhered part even when it passes through severe hot-humid conditions and a reflow process, adhesion | attachment for semiconductors which has the adhesive bond layer which consists of this adhesive composition A sheet and a method for manufacturing a semiconductor device using the sheet can be provided.

  Hereinafter, details of the method for manufacturing a semiconductor adhesive composition, a semiconductor adhesive sheet, and a semiconductor device of the present invention will be described. Hereinafter, the adhesive layer formed from the adhesive composition for semiconductors of the present invention is also simply referred to as “adhesive layer”.

[Adhesive composition for semiconductor]
The adhesive composition for a semiconductor of the present invention contains (A) a specific acrylic copolymer, (B) an epoxy thermosetting resin, and (C) a thermosetting agent. Moreover, in order to improve the various physical properties of the said adhesive composition, another component may be mix | blended as needed. Hereinafter, each of these components will be described in detail.

Acrylic copolymer (A);
The adhesive composition for a semiconductor of the present invention has 3 to 10% by weight of a structural unit derived from a hydroxyl group-containing (meth) acrylic acid ester as an adhesive component, and a weight average molecular weight of 100,000 to 1,000,000. The acrylic copolymer (A) which is 000 is contained. For this reason, the adhesive composition for semiconductors of this invention has high adhesiveness with respect to a to-be-adhered part even when it passes through severe heat-humidity conditions and a reflow process.

  The amount of the structural unit derived from the hydroxyl group-containing (meth) acrylic acid ester is 3 to 10% by weight, preferably 5 to 7% by weight when the amount of the acrylic copolymer (A) is 100% by weight. When this amount is 3% by weight or more, the adhesive layer made of the adhesive composition for a semiconductor of the present invention exhibits excellent adhesive force to a semiconductor wafer or the like. Moreover, when this amount is 10% by weight or less, the adhesive layer made of the adhesive composition for semiconductors of the present invention is excellent for semiconductor wafers and the like even after being exposed to a high humidity and high heat environment. Indicates adhesive strength.

  The weight average molecular weight (Mw) of the acrylic copolymer (A) is 100,000 to 1,000,000, preferably 200,000 to 700,000, more preferably 300,000 to 500,000. It is.

  Mw of the acrylic copolymer (A) is a polystyrene equivalent value measured by a gel permeation chromatography (GPC) method, and the measurement conditions are as described in the examples.

  The glass transition temperature (Tg) of the acrylic copolymer (A) is preferably -20 to 70 ° C, more preferably 0 to 50 ° C. If the Tg of the acrylic copolymer (A) is too low, the peeling force between the adhesive layer and the substrate may be increased, resulting in chip pickup failure. If the Tg of the acrylic copolymer (A) is too high, the adhesive force for fixing the wafer may be insufficient.

  Examples of the hydroxyl group-containing (meth) acrylic acid ester include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate.

  As the monomer for deriving a structural unit other than the structural unit derived from the hydroxyl group-containing (meth) acrylic acid ester, which the acrylic copolymer (A) has, (meth) acrylic acid other than the hydroxyl group-containing (meth) acrylic acid ester And esters and derivatives thereof. Specific examples include (meth) acrylic acid having 1 to 18 carbon atoms in an alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Alkyl ester; cyclic skeletons such as (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, imide acrylate, etc. (Meth) acrylic ester having; glycidyl acrylate, glycidyl methacrylate and the like. Moreover, acrylic acid, methacrylic acid, itaconic acid, etc. are also mentioned.

These may be used alone or in combination of two or more.
As the acrylic copolymer (A), only a structural unit derived from a hydroxyl group-containing (meth) acrylate ester and a structural unit derived from a (meth) acrylate ester other than the hydroxyl group-containing (meth) acrylate ester are substantially included. (That is, a copolymer having a total of 99% by weight or more, for example, 100% by weight) is preferable.

  Further, vinyl acetate, acrylonitrile, styrene, or the like may be used as a raw material monomer in addition to (meth) acrylic acid esters other than the above-mentioned hydroxyl group-containing (meth) acrylic acid esters and derivatives thereof as long as the object of the present invention is not impaired. .

Epoxy thermosetting resin (B);
Various conventionally known epoxy resins can be used as the epoxy thermosetting resin (B). Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenylene skeleton type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, polyfunctional epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type. Two or more functional groups are contained in structural units such as epoxy resins, triphenolmethane type epoxy resins, heterocyclic type epoxy resins, stilbene type epoxy resins, condensed ring aromatic hydrocarbon-modified epoxy resins, and halides thereof. Epoxy resin. These epoxy resins may be used alone or in combination of two or more.

Although the epoxy equivalent of an epoxy resin is not specifically limited, Preferably it is 150-1000 g / eq. The epoxy equivalent is a value measured according to JIS K7236.
In the adhesive composition of the present invention, the content of the epoxy thermosetting resin (B) is usually 1 to 1500 parts by weight, preferably 3 to 1000 parts by weight, with respect to 100 parts by weight of the acrylic copolymer (A). Part. If the content of the epoxy thermosetting resin (B) is less than the above range, an adhesive layer having sufficient adhesive strength may not be obtained. On the other hand, if the content of the epoxy thermosetting resin (B) exceeds the above range, the adhesive force between the adhesive layer and the substrate becomes too high, and chip pick-up failure may occur.

Thermosetting agent (C);
The thermosetting agent (C) functions as a thermosetting agent for the epoxy thermosetting resin (B).
Examples of the thermosetting agent (C) include compounds having two or more functional groups capable of reacting with an epoxy group in the molecule, such as phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, acids. An anhydride group etc. are mentioned. In these, a phenolic hydroxyl group, an amino group, and an acid anhydride group are preferable, and a phenolic hydroxyl group and an amino group are more preferable.

  Specific examples of the thermosetting agent (C) include phenolic thermosetting agents such as novolac-type phenolic resin, dicyclopentadiene-based phenolic resin, polyfunctional phenolic resin, and aralkylphenolic resin; amine-based heat such as DICY (dicyandiamide) A curing agent is mentioned. A thermosetting agent (C) may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the thermosetting agent (C) is usually 0.1 to 500 parts by weight, preferably 1 to 200 parts per 100 parts by weight of the epoxy thermosetting resin (B). Parts by weight. When content of a thermosetting agent (C) is less than the said range, the sclerosis | hardenability of adhesive composition may be insufficient and the adhesive bond layer which has sufficient adhesive force may not be obtained. When the content of the thermosetting agent (C) exceeds the above range, the moisture absorption rate of the adhesive composition may increase, and the reliability of the semiconductor package may decrease.

Curing accelerator (D);
In the present invention, a curing accelerator (D) may be used to adjust the curing rate of the adhesive composition. Examples of the curing accelerator (D) include compounds capable of promoting the reaction between an epoxy group and a phenolic hydroxyl group. Specifically, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris ( Tertiary amines such as dimethylaminomethyl) phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole; tributylphosphine, And organic phosphines such as diphenylphosphine and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. A hardening accelerator (D) may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the curing accelerator (D) is preferably 0.001 to 100 parts by weight of the total of the epoxy thermosetting resin (B) and the thermosetting agent (C). 100 parts by weight, more preferably 0.01 to 50 parts by weight, still more preferably 0.1 to 10 parts by weight. When content of a hardening accelerator (D) exceeds the said range, it may be inferior to the storage stability of an adhesive composition or an adhesive sheet.

Energy beam polymerizable compound (E);
The adhesive composition of the present invention may contain an energy beam polymerizable compound (E). By polymerizing the energy ray polymerizable compound (E) by energy ray irradiation, the adhesive force of the adhesive layer can be reduced. For this reason, delamination between the base material and the adhesive layer can be easily performed in the semiconductor chip pick-up process.

  The energy beam polymerizable compound (E) is a compound that polymerizes and cures when irradiated with energy rays such as ultraviolet rays and electron beams. Examples of the energy ray polymerizable compound (E) include compounds having one or more energy ray polymerizable double bonds in the molecule, for example, acrylate compounds.

  Examples of the acrylate compounds include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6- Examples include hexanediol diacrylate, dicyclopentadiene dimethoxydiacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer.

The molecular weight (in the case of an oligomer or polymer, the weight average molecular weight) of the energy beam polymerizable compound (E) is usually about 100 to 30,000, preferably about 200 to 9000.
In the adhesive composition of the present invention, the content of the energy beam polymerizable compound (E) is usually 1 to 400 parts by weight, preferably 3 to 300 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). Parts, more preferably 10 to 200 parts by weight. When the content of the energy beam polymerizable compound (E) exceeds the above range, the adhesive force of the adhesive layer to an organic substrate, a lead frame or the like may be reduced.

Photopolymerization initiator (F);
When using the adhesive composition of the present invention, it is preferable to reduce the adhesive strength of the adhesive layer by irradiating energy rays such as ultraviolet rays. By including the photopolymerization initiator (F) in the adhesive composition, the polymerization / curing time and the amount of light irradiation can be reduced.

  As the photopolymerization initiator (F), benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethyl Thioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2,4,6-trimethylbenzoyldiphenylphos Examples include fin oxide and β-chloranthraquinone. A photoinitiator (F) may be used individually by 1 type, and may use 2 or more types together.

  The mixing ratio of the photopolymerization initiator (F) is theoretically determined based on the amount of unsaturated bonds present in the adhesive composition, the reactivity thereof, and the reactivity of the photopolymerization initiator used. Should be, but not always easy in complex mixture systems. As a general guideline, the content of the photopolymerization initiator (F) is usually 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of the energy beam polymerizable compound (E). It is. If the content of the photopolymerization initiator (F) is less than the above range, there may be insufficient photopolymerization and satisfactory pick-up properties may not be obtained. The curability of the agent composition may be insufficient.

Coupling agent (G);
In the present invention, a coupling agent (G) may be used in order to further improve the adhesion and adhesion of the adhesive composition to the adherend. Moreover, the water resistance can be further improved by using a coupling agent (G), without impairing the heat resistance of the hardened | cured material obtained by hardening | curing adhesive composition.

  As the coupling agent (G), a compound having a group that reacts with a functional group of the acrylic copolymer (A) or the epoxy thermosetting resin (B) is preferably used. As the coupling agent (G), a silane coupling agent is preferable.

  As silane coupling agents, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacrylopropyl) Trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N-phenyl -Γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltrimethoxysilane , Methyltri Examples include ethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. A silane coupling agent may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of the present invention, the content of the coupling agent (G) is usually 0.1 with respect to a total of 100 parts by weight of the acrylic copolymer (A) and the epoxy thermosetting resin (B). ~ 20 parts by weight. If the content of the coupling agent (G) is less than the above range, the above effect may not be obtained, and if it exceeds the above range, it may cause outgassing.

Inorganic filler (H);
In the present invention, an inorganic filler (H) may be used. By blending the inorganic filler (H) into the adhesive composition, the thermal expansion coefficient of the composition can be adjusted. By optimizing the thermal expansion coefficient of the adhesive layer after curing with respect to the semiconductor chip, the lead frame, and the organic substrate, the package reliability can be further improved. In addition, it is possible to further reduce the moisture absorption rate after curing of the adhesive layer.

Examples of the inorganic filler (H) include powders such as silica, alumina, talc, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, beads formed by spheroidizing these, single crystal fibers, glass fibers, and the like. Among these, silica filler and alumina filler are preferable. An inorganic filler (H) may be used individually by 1 type, and may use 2 or more types together.
In the adhesive composition of the present invention, the content of the inorganic filler (H) is usually 0 to 80% by weight with respect to the entire adhesive composition.

Other ingredients;
The adhesive composition of the present invention may contain various additives as necessary in addition to the above components. Examples of the various additives include flexible components such as polyester resins, plasticizers, antistatic agents, antioxidants, pigments, and dyes.

  The adhesive composition of the present invention and the adhesive layer formed from the adhesive composition are excellent in storage stability, have adhesiveness (for example, pressure-sensitive adhesiveness) and heat-curing property, and can adhere various adherends in an uncured state. It has a function to hold temporarily. In particular, even after storage for a certain period of time, it is possible to give a cured product with high impact resistance through heat curing, and it has an excellent balance between shear strength and peel strength, and even under severe heat and humidity conditions. Sufficient adhesion can be maintained.

The adhesive composition of the present invention is obtained by mixing each of the above components at an appropriate ratio. In mixing, each component may be diluted with a solvent in advance, or a solvent may be added during mixing.
The adhesive composition of the present invention can be suitably used as a material for forming an adhesive layer constituting a so-called dicing sheet, die bonding sheet, dicing die bonding sheet, particularly a dicing die bonding sheet.

[Adhesive sheet]
The adhesive sheet for semiconductor of the present invention has an adhesive layer made of the above-described adhesive composition for semiconductor formed on a substrate. The shape of the adhesive sheet of the present invention can be any shape such as a tape shape or a label shape.

  As the base material of the adhesive sheet, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film , Polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, Transparent films such as fluororesin films; colored transparent films or colored opaque films obtained by coloring the transparent films; Such as bridge film or a laminated film, and the like.

  The adhesive sheet of the present invention is preferably irradiated with energy rays such as ultraviolet rays from the substrate side when used, and therefore the substrate is preferably transparent to the energy rays.

  Also, usually, the adhesive sheet of the present invention is affixed to an adherend such as a semiconductor wafer, and after subjecting the adherend to the required processing, the adhesive layer remains adhered to the adherend and peels off from the substrate. To do. That is, the adhesive layer is suitably used for a process including a step of transferring the adhesive layer from the base material to the adherend. For this reason, the surface tension of the surface in contact with the adhesive layer of the substrate is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. The lower limit is usually about 25 mN / m. Such a substrate having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the substrate and performing a release treatment.

  As the release agent used for the substrate release treatment, release agents such as alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax are used. In particular, alkyd, silicone, and fluorine are used. The release agent is preferable because it has heat resistance.

  In order to release the surface of the substrate using the above release agent, the release agent is used without a solvent, or diluted or emulsified with a solvent, and (1) a gravure coater, a Mayer bar coater, an air knife coater, a roll coater, etc. The release agent is applied to the surface of the substrate and cured at room temperature, heat, or electron beam, or (2) wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, etc. Thus, a laminate of the base material and the layer made of the release agent may be formed.

  The thickness of a base material is 10-500 micrometers normally, Preferably it is 15-300 micrometers, Most preferably, it is about 20-250 micrometers. The thickness of the adhesive layer is usually 1 to 500 μm, preferably 5 to 300 μm, particularly preferably about 10 to 150 μm.

  The method for producing the adhesive sheet is not particularly limited, and may be produced by applying and drying the adhesive composition constituting the adhesive layer on the substrate, and the adhesive layer is provided on the release film. Alternatively, it may be produced by transferring it to the substrate. In addition, in order to protect an adhesive bond layer before using an adhesive sheet, you may laminate | stack a peeling film on the upper surface of an adhesive bond layer. Further, a pressure-sensitive adhesive layer or a pressure-sensitive adhesive tape may be separately provided on the outer peripheral portion of the surface of the adhesive layer in order to fix another jig such as a ring frame.

[Method of Manufacturing Semiconductor Device]
The method of using the adhesive sheet for semiconductors of the present invention will be described taking as an example the case where the adhesive sheet is applied to the manufacture of a semiconductor device (for example, a semiconductor package). A manufacturing method of a semiconductor device includes a step of sticking a semiconductor wafer on an adhesive layer of the adhesive sheet for semiconductor, dicing the semiconductor wafer into a semiconductor chip, and fixing the adhesive layer to the back surface of the semiconductor chip to leave a base material. And a step of thermocompression bonding the semiconductor chip to the adherend via an adhesive layer.

Details of the method for manufacturing the semiconductor device will be described below.
In the semiconductor device manufacturing method, first, one surface of the semiconductor wafer and the ring frame are placed on the adhesive layer of the adhesive sheet of the present invention, and lightly pressed to fix the semiconductor wafer. Next, the semiconductor wafer is cut using a cutting means such as a dicing saw to obtain a semiconductor chip. The cutting depth at this time is a depth that takes into account the sum of the thickness of the semiconductor wafer and the adhesive layer and the wear of the dicing saw.

  When the adhesive layer contains the energy ray polymerizable compound (E), the adhesive layer is irradiated with energy rays from the substrate side, the cohesive force of the adhesive layer is increased, and the adhesive layer is interposed between the adhesive layer and the substrate. Reduce the adhesive strength. Examples of the energy rays to be irradiated include ultraviolet rays (UV) and electron beams (EB), and preferably ultraviolet rays are used. The energy beam irradiation may be performed at any stage after the semiconductor wafer is pasted to before the semiconductor chip is peeled off (pickup). Further, the energy beam irradiation may be performed in a plurality of times.

  Then, if necessary, when the adhesive sheet is expanded, the interval between the semiconductor chips is expanded, and the semiconductor chips can be picked up more easily. At this time, a deviation occurs between the adhesive layer and the base material, the adhesive force between the adhesive layer and the base material is reduced, and the pick-up property of the semiconductor chip is improved.

When the semiconductor chip is picked up in this manner, the cut adhesive layer can be fixedly left on the back surface of the semiconductor chip and peeled off from the substrate.
Next, the semiconductor chip is mounted (thermocompression bonding) on the adherend via the adhesive layer. The adherend is, for example, a die pad portion of an organic substrate or a lead frame, or another semiconductor chip (lower chip) on the lower stage. The die pad part or the lower chip is heated before mounting the semiconductor chip or immediately after mounting. The heating temperature is usually 80 to 200 ° C., preferably 100 to 180 ° C., the heating time is usually 0.1 seconds to 5 minutes, preferably 0.5 seconds to 3 minutes, and the pressure during mounting is usually 1 kPa to 200 MPa.

  After the semiconductor chip is placed on the die pad portion or the lower chip, heating may be further performed as necessary. The heating conditions at this time are in the above heating temperature range, and the heating time is usually 1 to 180 minutes, preferably 10 to 180 minutes.

  Alternatively, the adhesive layer may be cured by using heat in resin sealing that is normally performed in package manufacturing, without temporarily performing the heat treatment after placement. In that case, in order to harden sealing resin, the heating for about 2 to 8 hours is normally performed at 150-180 degreeC. Instead of the above heat treatment, a heat treatment in the sealing step may be used.

  Through such a process, the adhesive layer is cured, and the semiconductor chip and the die pad portion or the lower chip can be firmly bonded. Since the adhesive layer is fluidized under die bonding conditions, the adhesive layer is sufficiently embedded in the unevenness of the die pad portion or the lower chip, and generation of voids can be prevented.

  That is, in the obtained mounting product, the adhesive which is a fixing means of the semiconductor chip is cured and is sufficiently embedded in the unevenness of the die pad portion or the lower chip, so even under severe conditions Sufficient package reliability is achieved.

  In addition, in the manufacturing method of the semiconductor chip device including the step of thermocompression bonding the semiconductor chip onto another semiconductor chip via an adhesive layer, the other semiconductor chip placed on the die pad portion of the organic substrate or the lead frame A step of thermocompression bonding the semiconductor chip via an adhesive layer, or a thermocompression bonding of the semiconductor chip via an adhesive layer on another semiconductor chip that is not placed on the die pad portion of the organic substrate or the lead frame. It includes a process.

  The adhesive composition and adhesive sheet of the present invention can be used for bonding semiconductor compounds, glass, ceramics, metals, etc., in addition to the above-described methods of use.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following examples and comparative examples, each evaluation was performed as follows.

Measurement of moisture absorption of the cured product;
The adhesive layers in the respective adhesive sheets prepared in Examples and Comparative Examples were laminated to a thickness of about 200 μm, irradiated with ultraviolet rays (350 mW / cm ² , 190 mJ / cm ² ), then heated at 125 ° C. for 60 minutes, Furthermore, it was heated at 175 ° C. for 120 minutes to be cured. The obtained cured product was baked at 175 ° C. for 30 minutes and then left in an environment of 85 ° C. and 85% RH for 168 hours, and the weight change of the cured product before and after being left was measured.

Shear adhesion measurement;
The surface was dry-polished using a wafer backside grind apparatus (DGP8760, manufactured by DISCO), and the dry-polishing surface of a silicon wafer (200 mm diameter, 500 μm thick) with a surface roughness (Ra) of 0.12 μm was carried out. The adhesive sheets obtained in Examples or Comparative Examples were attached using a tape mounter (Adwill (registered trademark) RAD2500 m / 8, manufactured by Lintec Corporation) and simultaneously fixed to the ring frame. Then, the ultraviolet-ray was irradiated from the base-material surface using the UV irradiation apparatus (The product made by Lintec, Adwill (trademark) RAD2000 m / 8). Next, dicing was performed using a dicing apparatus (manufactured by Disco Corporation, DFD651) into chips having a size of 5 mm × 5 mm. The amount of cutting during dicing was set to 20 μm with respect to the base film of the adhesive sheet.

  As a wiring board for die-bonding the chip, a circuit pattern is formed on the copper foil of a copper foil-clad laminate (manufactured by Mitsubishi Gas Chemical Company, BT Resin CCL-HL832HS), and a solder resist (manufactured by Taiyo Ink Co., PSR-4000) is formed on the pattern. A two-layer double-sided substrate (manufactured by Hitachi Ultra LSI Systems, LNTEG0001, size 157 mm × 70 mm × 0.22 t, maximum unevenness 15 μm) having AUS303) was used. A silicon chip diced in a size of 5 mm × 5 mm is picked up together with the adhesive layer, bonded through the adhesive layer of the adhesive sheet at 100 ° C. and 300 gf / chip for 1 second, and then at 60 ° C. at 60 ° C. The test piece was obtained by heating for 120 minutes and further heating at 175 ° C. for 120 minutes to cure the adhesive layer. The test piece immediately after curing is hereinafter referred to as “test piece (A)”.

  The test piece (A) was left in an environment of 85 ° C. and 85% RH for 48 hours to absorb moisture, and then the test piece (A) was subjected to IR reflow (reflow oven) with a maximum temperature of 260 ° C. and a heating time of 1 minute. : Sagami Riko, WL-15-20DNX type) was performed three times, and further a pressure cooker test (conditions: 121 ° C., 2.2 atm, 100% RH) was performed for 168 hours. The test piece after the wet heat durability test is hereinafter referred to as “test piece (I)”.

  Each of the obtained test pieces (a) and (b) was left on a measurement stage set to 250 ° C. of a bond tester (Dage, Bond Tester Series 4000) for 30 seconds, and then 10 μm from a silicon wafer test piece. The stress (shearing adhesive force) (N) is applied when stress is applied in the horizontal direction (shear direction) to the bonding surface at a speed of 200 μm / s from the position of the height of the test piece and the bonding state between the test piece chip and the substrate is broken. It was measured. Moreover, the average value of the measured value of 6 samples was employ | adopted as a measured value of 1 level (each Example and a comparative example).

[Measurement method of weight average molecular weight]
The weight average molecular weight (Mw) of the acrylic copolymer (A) was measured by the following method.
・ Measurement method: Gel permeation chromatography (GPC) method ・ Standard material: polystyrene standard ・ Device: HLC-8220 GPC manufactured by Tosoh Corporation
-Column: Tosoh Corporation TSKgelGMHXL->TSKgelGMHXL-> TSKgel2000HXL
・ Solvent: Tetrahydrofuran ・ Concentration: 1%
・ Injection amount: 80 μm
・ Flow rate: 1.0 ml / min
・ Measurement temperature: 40 ℃
・ Detector: Differential refractometer

[Examples and Comparative Examples]
An adhesive composition having the composition described in Table 1 was used. In Table 1, the numerical value of each component shows the weight part of solid content conversion, and solid content means all components other than a solvent in this invention. After applying and drying the adhesive composition having the composition shown in Table 1 on a silicone-treated release film (SP-PET3811 (S)) to a thickness of about 60 μm after drying, a polyethylene film as a base material The adhesive sheets of Examples 1 to 4 and Comparative Examples 1 and 2 were obtained by bonding with (thickness 100 μm, surface tension 33 mN / m) and transferring the adhesive layer onto the substrate.

表２より、実施例では、促進処理後においても高いせん断接着力（１００Ｎ／ｃｈｉｐ以上）を維持し、また厳しいリフロー条件に曝された場合であっても高いパッケージ信頼性を有している。一方比較例では、湿熱耐久試験後の強度に劣り、またパッケージ信頼性も低下している。
表１の各材料は、下記に示すとおりである。

From Table 2, in the examples, high shear adhesive strength (100 N / chip or more) is maintained even after the acceleration treatment, and high package reliability is obtained even when exposed to severe reflow conditions. On the other hand, in the comparative example, the strength after the wet heat durability test is inferior, and the package reliability is also lowered.
Each material of Table 1 is as shown below.

(A) Acrylic copolymer (A) -1: An acrylic ester copolymer comprising methyl acrylate (MA) and 2-hydroxyethyl acrylate (HEA) (MA / HEA = 90% by weight / 10% by weight) (Mw = 300,000, Tg = 7 ° C.)
(A) -2: Acrylate ester copolymer (Mw = 310,000, Tg = 8 ° C.) consisting of MA and HEA (MA / HEA = 93 wt% / 7 wt%)
(A) -3: Acrylate ester copolymer (Mw = 300,000, Tg = 9 ° C.) consisting of MA and HEA (MA / HEA = 95 wt% / 5 wt%)
(A) -4: Acrylate ester copolymer (Mw = 310,000, Tg = 9 ° C.) consisting of MA and HEA (MA / HEA = 97 wt% / 3 wt%)
(A) -1: Acrylic acid ester polymer (Mw = 310,000, Tg = 10 ° C.) consisting of MA and HEA (MA / HEA = 100 wt% / 0 wt%)
(A) -2: Acrylate ester copolymer (Mw = 310,000, Tg = 5 ° C.) consisting of MA and HEA (MA / HEA = 80 wt% / 20 wt%)

(B) Epoxy thermosetting resin (B) -1: Bisphenol A type epoxy resin
(Japan Epoxy Resin Co., Ltd. product: jER828, epoxy equivalent 184-194 g / eq)
(B) -2: Cresol novolac type epoxy resin
(Nippon Kayaku Co., Ltd. product: ECON-104S, epoxy equivalent 213-223g / eq)
(B) -3: Multifunctional epoxy resin
(Nippon Kayaku Co., Ltd .: EPPN-502H, epoxy equivalent of 158 to 178 g / eq)
(B) -4: Dicyclopentadiene (DCPD) type epoxy resin
(DIC: EPICLON HP-7200HH, epoxy equivalent 265-300 g / eq)

(C) Thermosetting agent : novolac type phenolic resin
(Showa Polymer Co., Ltd .: Shonor BRG-556)
(D) Curing accelerator : 2-phenyl-4,5-dihydroxymethylimidazole (Shikoku Kasei Kogyo Co., Ltd .: Curesol 2PHZ)
(E) Energy beam polymerizable compound : dicyclopentadiene dimethoxydiacrylate (manufactured by Nippon Kayaku Co., Ltd .: KAYARAD R-684)
(F) Photopolymerization initiator : α-hydroxycyclohexyl phenyl ketone
(Ciba Specialty Chemicals Co., Ltd .: Irgacure 184)
(G) Coupling agent : Silane coupling agent (Mitsubishi Chemical Corporation MKC silicate MSEP2)
(H) Inorganic filler : Si filler (manufactured by Admatechs: Admafine SC2050)
(I) Other components : Thermoplastic polyester resin (Toyobo Co., Ltd .: Byron 220)

Claims (3)

(A) an acrylic copolymer having 3 to 10% by weight of a structural unit derived from a hydroxyl group-containing (meth) acrylic acid ester and having a weight average molecular weight of 100,000 to 1,000,000,
(B) An epoxy thermosetting resin, and (C) a semiconductor adhesive composition containing a thermosetting agent.   An adhesive sheet for semiconductor, comprising an adhesive layer made of the adhesive composition for semiconductor according to claim 1 formed on a substrate.   A semiconductor wafer is attached to the adhesive layer of the semiconductor adhesive sheet according to claim 2, the semiconductor wafer is diced to form a semiconductor chip, and the adhesive layer remains fixed on the back surface of the semiconductor chip and peeled off from the substrate. And a method of manufacturing a semiconductor device, comprising a step of thermocompression bonding the semiconductor chip to an adherend via an adhesive layer.