WO2011125778A1 - Adhesive composition, bonding sheet, and semiconductor device - Google Patents

Abstract

Disclosed is an adhesive composition which contains (A) a thermoplastic resin that has a weight average molecular weight of 10,000-150,000 and a viscosity at 25˚C of 5-300 poises as dissolved in N-methyl-2-pyrrolidone such that the resin content is 25% by mass and (B) a thermosetting component. The thermosetting component (B) contains (B1) a reactive plasticizer having an allyl group or an epoxy group, (B2) a compound having a styryl group and (B3) a compound having a maleimide group.

Description

Adhesive composition, adhesive sheet, and semiconductor device

The present invention relates to an adhesive composition, an adhesive sheet, and a semiconductor device.

Conventionally, silver paste has been mainly used for joining a semiconductor element and a support member. However, with the recent increase in the size of semiconductor elements and the reduction in size and performance of semiconductor packages, the supporting members used are also required to be reduced in size and size. In response to these requirements, silver paste is used due to wet spreading, defects in wire bonding caused by protrusions and inclination of semiconductor elements, difficulty in controlling the thickness of silver paste, and generation of voids in silver paste. It has become impossible to sufficiently cope with the joining using. Therefore, in recent years, an adhesive sheet having a film-like adhesive layer has been used in order to cope with the above requirement (see, for example, Patent Documents 1 and 2).

This adhesive sheet is used in semiconductor device manufacturing methods such as an individual piece attaching method and a wafer back surface attaching method.

In the case of manufacturing a semiconductor device by the former single piece attaching method, first, a reel-like adhesive sheet is cut into pieces by cutting or punching, and then an adhesive layer is attached to a support member. Then, the semiconductor element separated by the dicing process is joined to the support member with the adhesive layer. Then, a semiconductor device is manufactured through assembly processes such as wire bonding and sealing (see, for example, Patent Document 3). However, in the case of the individual sticking method, a dedicated assembly device for cutting out the adhesive sheet and adhering it to the support member is necessary, and thus there is a problem that the manufacturing cost is higher than the method using the silver paste. It was.

On the other hand, when manufacturing a semiconductor device by a wafer back surface attaching method, first, an adhesive layer is attached to the back surface of the semiconductor wafer, and a dicing sheet is attached to the other surface of the adhesive layer. Thereafter, by dicing, the semiconductor wafer is separated into pieces with the adhesive layer bonded to obtain a semiconductor element. Next, the semiconductor element with the adhesive layer is picked up and joined to the support member. Then, a semiconductor device is obtained through assembly processes such as wire bonding and sealing. This wafer backside pasting method does not require a dedicated assembling device like the individual piece pasting method, and the conventional silver paste assembling device is used as it is or a part of the device such as adding a hot plate there. It can be adopted by improvement. For this reason, the wafer back surface pasting method is attracting attention as a method in which the manufacturing cost is kept relatively low among the assembly methods using an adhesive sheet (see, for example, Patent Document 4).

Recently, in addition to downsizing, thinning and high performance of semiconductor elements, multi-functionalization has progressed, and semiconductor devices in which a plurality of semiconductor elements are stacked are rapidly increasing. In addition, semiconductor devices are progressing in the direction of thinning. For this purpose, a semiconductor wafer that is further thinned is used.

As the semiconductor device becomes thinner, the adhesive layer between the semiconductor elements and the adhesive layer between the lowermost semiconductor element and the substrate are also required to be thinned, and as the semiconductor element becomes extremely thin. In order to suppress cracking of semiconductor elements due to impact during wire bonding and improve ultrasonic efficiency during wire bonding, higher elasticity of the adhesive layer for supporting and fixing ultrathin semiconductor elements is required more than ever. It has become.

Also, for the purpose of simplifying the assembly process, an adhesive sheet in which a dicing sheet is bonded to one surface of the adhesive layer, that is, a film in which a dicing sheet and a die bond film are integrated (hereinafter referred to as “dicing / die bond one”). In some cases, the process using the “body-shaped film”) may be simplified in the bonding process to the back surface of the wafer. According to this method, the process of attaching the film to the back surface of the wafer can be simplified, so that the risk of wafer cracking can be reduced. The softening temperature of the dicing tape is usually 100 ° C. or lower. Therefore, especially in the case of the dicing die bond integrated film, it is possible to apply the dicing tape at a temperature lower than 100 ° C. in consideration of the softening temperature of the dicing tape and the suppression of the warpage of the wafer, that is, excellent processing at a low temperature. The adhesive sheet is required to have properties.

A semiconductor device manufactured using an adhesive sheet is required to achieve a sufficient level in terms of reliability, more specifically, heat resistance, moisture resistance, and reflow resistance. In order to ensure reflow resistance, it is required to maintain a high adhesive strength that can suppress peeling or breakage of the adhesive layer at a reflow temperature of around 260 ° C. As described above, there is a strong demand for an adhesive sheet that can achieve high compatibility between process characteristics such as workability at low temperatures and mounting efficiency of ultrathin semiconductor elements, and reliability of semiconductor devices including reflow resistance.

So far, in order to achieve both low-temperature processability and heat resistance, a film adhesive that combines a thermoplastic resin having a relatively low glass transition temperature (Tg) and a thermosetting resin has been proposed (for example, (See Patent Document 5).

Japanese Patent Laid-Open No. 3-192178 JP-A-4-234472 Japanese Patent Laid-Open No. 9-17810 Japanese Patent Laid-Open No. 4-196246 Japanese Patent No. 3014578

However, conventional adhesives for fixing semiconductor elements cannot achieve a sufficient level in terms of curability due to thermal history received in the assembly process after die bonding, as well as compatibility with workability at low temperatures and reflow resistance. I understood that. Further, there is a demand for further improvement of the thin film formability of the adhesive for fixing a semiconductor element corresponding to multi-layer lamination of semiconductor elements and thinning of a semiconductor device. Furthermore, with the further improvement of ultrasonic processing efficiency in the wire bonding process using ultra-thin semiconductor elements, it is received in the assembly process after die bonding for the purpose of suppressing cracks in ultra-thin semiconductor elements due to impact in the process. It is necessary more than ever to advance the curing of the adhesive with a thermal history to achieve high elasticity.

The present invention has been made in view of the above-mentioned problems of the prior art, and can highly satisfy thin film formability, low-temperature workability (low-temperature sticking property), and reflow resistance, and die bonding. The main object is to provide an adhesive composition that can achieve sufficient elasticity at the same time as the heat history received in the subsequent assembly process, and at the same time achieve high elasticity, and an adhesive sheet and a semiconductor device using the same.

The present invention is (A) 25 ° C. when dissolved in N-methyl-2-pyrrolidone (hereinafter referred to as NMP) so that the weight average molecular weight is 10,000 to 150,000 and the resin content is 25% by mass. An adhesive composition containing a thermoplastic resin having a viscosity of 5 to 300 poise and (B) a thermosetting component, wherein (B) the thermosetting component is (B1) an allyl group or Provided is an adhesive composition comprising a reactive plasticizer having an epoxy group, (B2) a compound having a styryl group, and (B3) a compound having a maleimide group.

The above-mentioned adhesive composition is excellent in thin film forming properties including thin film coatability, and the adhesive sheet obtained from this adhesive composition can highly satisfy the low temperature sticking property. Specifically, an adhesive sheet having a thinner adhesive layer can be obtained from the adhesive composition of the present invention, and the adhesive sheet can be applied to an adherend such as a semiconductor element and a support member at a lower temperature. In addition, die bonding can be performed under conditions of low temperature, low pressure and short time. It also has thermal fluidity that enables low-pressure embedding in the wiring step on the substrate during die bonding. Furthermore, the adhesive sheet is easy to handle and contributes to the efficiency of the semiconductor device assembly process such as the dicing process. A semiconductor device having an adhesive layer obtained from the adhesive composition can highly satisfy the reliability of the semiconductor device such as reflow resistance. In addition, the thermal history received in the assembly process after die bonding, that is, the curing of the adhesive composition is sufficiently progressed by the thermal history such as precure (step cure) and / or wire bond, and its elastic modulus is improved. Improves the efficiency of sonication during wire bonding, suppresses cracking or destruction of ultrathin semiconductor elements due to impact during wirebonding, and improves assembly efficiency of semiconductor devices with ultrathin semiconductor elements stacked in multiple layers Can contribute.

The (B1) reactive plasticizer having an allyl group or an epoxy group preferably contains diallyl bisphenol A diglycidyl ether or a polycondensate of allylated bisphenol A and epichlorohydrin. Moreover, the reactive plasticizer which has the said (B1) allyl group or an epoxy group may contain the epoxy group containing liquid acrylic polymer. When the adhesive composition has the above-described configuration, both the thermal fluidity at the B stage and the thermal fluid suppression at the C stage can be improved.

The compound (B2) having a styryl group preferably contains an acrylic polymer having a styryl group in the side chain. When the adhesive composition contains an acrylic polymer having a styryl group in the side chain, the resulting adhesive sheet has low outgassing property, curability in the heat history received in the semiconductor device assembly process, high temperature elastic modulus, moisture resistance And high temperature adhesiveness improves further.

The (B) thermosetting component preferably further comprises (B4) a solid epoxy resin at 25 ° C. and 1 atm. Solid epoxy resins tend to have a relatively large molecular weight and a large number of functional groups compared to liquid epoxy resins, so that the crosslink density after curing is high, and the low-temperature sticking property and reflow resistance are further improved. improves.

The (A) thermoplastic resin preferably has a Tg of 100 ° C. or lower, and is preferably a polyimide resin. When a thermoplastic resin has the said structure, heat resistance, purity, and the favorable adhesiveness with respect to a to-be-adhered body can be achieved further highly. Here, purity is an index of the amount of impurity ions such as alkali metal ions, alkaline earth metal ions, halogen ions, particularly chlorine ions and hydrolyzable chlorine, contained in the thermoplastic resin.

It is preferable that the adhesive composition further includes (C) a filler. When the adhesive composition further contains (C) filler, in particular, it is possible to achieve a high degree of easy cutting property during dicing, easy peeling from the dicing tape during pick-up, and reflow resistance. Moreover, it can contribute to the improvement of the elastic modulus due to the thermal history received in the assembly process, the low hygroscopicity, and the breaking strength in the reflow process.

The adhesive composition is preferably used for fixing a semiconductor element, and can be suitably used for manufacturing a semiconductor device in which a plurality of semiconductor elements are stacked using an ultra-thin wafer by a wafer back surface pasting method. .

The present invention provides an adhesive sheet provided with an adhesive layer in which the adhesive composition is formed into a film. An adhesive sheet having a film-like adhesive layer is easy to handle and contributes to the efficiency of a semiconductor device assembly process such as a dicing process.

It is preferable that the adhesive sheet further includes a support film, and the adhesive layer is provided on the support film.

The adhesive sheet may further include a dicing sheet, and the adhesive layer may be provided on the dicing sheet.

The dicing sheet may have a base film and an adhesive layer provided on the base film, and the adhesive layer may be provided on the adhesive layer.

When the adhesive sheet includes a support film or a dicing sheet, the handleability of the adhesive sheet is further improved. In particular, an adhesive sheet including a dicing sheet can be used as a dicing / die bonding integrated film having both functions of a dicing sheet and a die bonding film, thereby further simplifying the manufacturing process of the semiconductor device.

The present invention is a semiconductor device comprising one or more semiconductor elements and a support member, wherein the semiconductor element, the support member, and / or the semiconductor elements are bonded together by the adhesive composition. Providing equipment.

The above semiconductor device can achieve multi-layer stacking and miniaturization of built-in ultra-thin semiconductor elements at the same time, and has high performance, high function and high reliability (especially reflow resistance, heat resistance, moisture resistance, etc.). In addition, even through a process using ultrasonic treatment such as wire bonding, it is possible to manufacture with high efficiency.

The adhesive composition of the present invention is excellent in thin film formability including thin film coatability, and the adhesive sheet obtained from the adhesive composition can highly satisfy the low temperature sticking property. Furthermore, the semiconductor device using the adhesive layer obtained from the adhesive composition is excellent in reflow resistance, and the adhesive layer can be sufficiently cured by the thermal history received in the assembly process after die bonding, and at the same time has a high elastic modulus. An agent layer can be obtained.

The adhesive composition of the present invention can be suitably used for manufacturing a semiconductor device in which a plurality of semiconductor elements are stacked using an ultra-thin wafer by a wafer back surface pasting method. When affixing a film-like adhesive layer, it is usually heated to a temperature at which the adhesive composition melts. By using the adhesive composition of the present invention, the film-like adhesive layer is applied to the back surface of the wafer at a low temperature. By sticking, the thermal stress on the wafer can be reduced. As a result, even when a wafer having a large diameter and a thin thickness is used, the occurrence of problems such as warpage can be remarkably suppressed.

According to the present invention, it is also possible to ensure thermal fluidity that enables good embedding in the wiring step on the substrate surface. Therefore, it can respond suitably to the manufacturing process of a semiconductor device in which a plurality of semiconductor elements are stacked. Furthermore, since high adhesive strength at high temperatures can be ensured, heat resistance and moisture resistance reliability can be improved, and the manufacturing process of the semiconductor device can be simplified.

The present invention is also advantageous in terms of suppressing chip skipping during dicing, improving workability during manufacturing of a semiconductor device such as pick-up properties, and reducing outgassing properties. In addition, stable characteristics can be maintained with respect to the assembly heat history of the package.

The semiconductor device of the present invention has a simplified manufacturing process and excellent reliability. The semiconductor device of the present invention can sufficiently achieve heat resistance and moisture resistance required when mounting a semiconductor element.

It is a schematic cross section showing one embodiment of an adhesive sheet. It is a schematic cross section which shows other embodiment of an adhesive sheet. It is a schematic cross section which shows other embodiment of an adhesive sheet. It is a schematic cross section which shows one Embodiment of an adhesive sheet provided with a dicing sheet. It is a schematic cross section which shows other embodiment of an adhesive sheet provided with a dicing sheet. 1 is a schematic cross-sectional view showing an embodiment of a semiconductor device. It is a schematic cross section which shows other embodiment of a semiconductor device. It is the schematic which shows an adhesive force evaluation apparatus.

DESCRIPTION OF SYMBOLS 1 ... Adhesive layer, 2 ... Support film, 3 ... Protective film, 5 ... Dicing sheet, 6 ... Adhesive layer, 7 ... Base film, 8 ... Die bonding layer (cured adhesive layer), 9, 9a, 9b: Semiconductor element (silicon chip, silicon wafer, etc.) 10 ... Supporting member, 11 ... Wire, 12 ... Sealing material, 13 ... Terminal, 31 ... Push-pull gauge, 35 ... 42 Alloy lead frame, 36 ... Hot plate, 100, 110, 120, 130, 140... Adhesive sheet, 200, 210... Semiconductor device, 300.

Hereinafter, preferred embodiments will be described in detail with reference to the drawings as the case may be. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. The dimensional ratios in the drawings are not limited to the illustrated ratios.

1 to 3 are cross-sectional views each showing a preferred embodiment of an adhesive sheet. The adhesive sheet 100 shown in FIG. 1 consists only of the adhesive layer 1 which shape | molded the adhesive composition of this invention in the film form. The thickness of the adhesive layer 1 is preferably 0.5 to 200 μm, more preferably 0.5 to 100 μm, and still more preferably 1 to 50 μm. The adhesive sheet 100 may be, for example, a tape shape having a width of about 1 to 20 mm or a sheet shape having a width of about 10 to 50 cm. In that case, the adhesive sheet 100 is preferably conveyed while being wound around a winding core. Thereby, storage and conveyance of the adhesive sheet 100 are facilitated. The adhesive sheet 100 may be a laminate in which a plurality of single-layer adhesive layers 1 are stacked and bonded together for the purpose of increasing the film thickness.

The adhesive sheet 110 shown in FIG. 2 includes a support film 2 and an adhesive layer 1 provided on both main surfaces thereof. The support film 2 functions as a base material that supports the adhesive layer 1. The adhesive layer 1 may be provided only on one side of the support film 2.

The adhesive sheet 120 shown in FIG. 3 includes a support film 2, an adhesive layer 1, and a protective film 3, which are laminated in this order. The protective film 3 is provided so as to cover the main surface of the adhesive layer 1 opposite to the support film 2 for the main purpose of preventing damage and contamination of the adhesive layer 1. Usually, after peeling off the protective film 3, the adhesive sheet 120 is used for die bonding.

It is preferable that the adhesive sheet can be attached to the adherend at a low temperature below the softening temperature of the protective tape and the dicing tape. The fact that the temperature at which bonding can be performed is low is also advantageous in terms of suppressing the warpage of the semiconductor wafer. Specifically, the temperature at which the adhesive layer 1 is attached to the adherend is preferably 10 to 150 ° C., more preferably 20 to 100 ° C., and still more preferably 20 to 80 ° C. In order to enable attachment at such a low temperature, the Tg of the adhesive layer 1 is preferably 100 ° C. or lower.

The adhesive layer 1 is obtained by forming the adhesive composition into a film. Hereinafter, the adhesive composition will be described in detail. The adhesive composition contains (A) a thermoplastic resin and (B) a thermosetting component.

(A) The Tg of the thermoplastic resin is preferably 100 ° C. or lower, more preferably −20 to 80 ° C. (A) If the Tg of the thermoplastic resin exceeds 100 ° C, the possibility that the temperature of application to the backside of the semiconductor wafer will exceed 150 ° C increases, and if the Tg is less than -20 ° C, adhesion in the B stage state The tackiness of the surface of the agent layer 1 becomes strong, and the handleability tends to gradually decrease.

(A) The above-mentioned Tg relating to the thermoplastic resin is a peak temperature of main dispersion observed when the temperature dependence of the dynamic viscoelasticity of the (A) thermoplastic resin formed into a film is measured. (A) The dynamic viscoelasticity of a thermoplastic resin is measured using, for example, a test piece having a thickness of 35 mm × 10 mm × 40 μm under the conditions of a heating rate of 5 ° C./min, a frequency of 1 Hz, and a measurement temperature of −150 to 300 ° C. Is done. At this time, the temperature at which tan δ (loss tangent) has a maximum value in the main dispersion (main dispersion temperature) is Tg. Viscoelasticity can be measured using a viscoelasticity analyzer (trade name: RSA-2) manufactured by Rheometrix Co., Ltd. The (A) thermoplastic resin is a linear or branched polymer that melts or softens by heating, deforms and flows by external force, and solidifies when cooled. Even if it has a group, it is included in (A) the thermoplastic resin as long as it is a resin having fluidity by heating as described above.

Such (A) thermoplastic resin is not particularly limited. For example, polyimide resin, polyamide resin, polyamideimide resin, polyetherimide resin, polyurethaneimide resin, polyurethaneamideimide resin, siloxane polyimide resin. , Polyesterimide resins or copolymers thereof, phenoxy resins, polysulfone resins, polyethersulfone resins, polyphenylene sulfide resins, polyester resins, polyetherketone resins, polyvinyl alcohol resins, polyvinyl butyral resins, styrene-maleimide copolymers, maleimides -Vinyl compound copolymer or (meth) acrylic copolymer.

(A) The thermoplastic resin has a weight average molecular weight of 10,000 to 150,000. When the weight average molecular weight exceeds 150,000, the thermal fluidity of the B stage tends to be lowered, and when the weight average molecular weight is less than 10,000, the film formability tends to be lowered. The weight average molecular weight is a standard polystyrene equivalent value obtained by GPC (high performance liquid chromatography (for example, trade name: C-R4A, manufactured by Shimadzu Corporation)). In the above GPC measurement, dimethylformamide (DMF) + lithium bromide (LiBr) (0.03 mol (vs DMF1L)) + phosphoric acid (0.06 mol (vs DMF1L)) is used as a solvent, and G6000H _XL is used as a column. + G4000H _XL + G2000H _XL (manufactured by Tosoh Corporation) was used. The sample concentration was 10 mg / 5 mL, the injection amount was 0.5 mL, the pressure was 100 kgf / cm ² , the flow rate was 1.00 mL / min, and the measurement temperature was 25 ° C.

The (A) thermoplastic resin has a viscosity at 25 ° C. of 5 to 300 poise when dissolved in NMP so that the resin content is 25% by mass, and preferably 10 to 200 poise. The viscosity is an index of polymer chain cohesiveness caused by entanglement of polymer chains of the thermoplastic resin, or intermolecular attraction due to interaction between polar groups contained in the molecule, and the larger this value, the higher the polymer It can be said that the cohesiveness of the chains is large. As the weight average molecular weight of the thermoplastic resin used increases and the concentration of the intramolecular polar group increases, the polymer chain cohesiveness increases and the viscosity of the NMP solution tends to increase. By using a thermoplastic resin in which the viscosity of the NMP solution is in the above range, it is possible to achieve both a good film forming property including a thin film forming property, a thermal fluidity, and an adhesive property at a high temperature. When the viscosity exceeds 300 poise, the thin film formability is reduced and the polymer chain cohesiveness is increased, so that the thermal fluidity in the B stage of the resulting adhesive composition tends to be reduced, and the viscosity is 5 If it is less than poise, the film obtained by film formation becomes brittle, the handleability as a film decreases, and the polymer chain cohesiveness decreases, so the toughness of the resulting adhesive layer and adhesion at high temperatures The strength tends to decrease.

In addition, the said viscosity is a measurement temperature: 25 degreeC, sample volume: 1.3cm < ³ >, rotation using the E-type viscosity meter by Tokyo Keiki Co., Ltd. which melt | dissolved the resin part of 25 mass%. Number: Value when measured under conditions of 5 rpm.

(A) When both the weight average molecular weight of the thermoplastic resin and the viscosity of the NMP solution exceed the upper limit of the above range, both the entanglement of the polymer chains and the intermolecular interaction (intermolecular interaction) due to the molecular structure increase. The toughness of the resulting adhesive layer and the physical properties (strength) at high temperatures are excellent, but the thermal fluidity of the B stage is reduced. On the other hand, when both (A) the weight average molecular weight of the thermoplastic resin and the viscosity of the NMP solution are less than the lower limit of the above range, both the entanglement of the polymer chain and the intermolecular interaction (intermolecular interaction) due to the molecular structure are both Therefore, although the thermal fluidity of the B stage is improved, the self-supporting property at the time of film formation is lowered (progresses toward embrittlement). In addition, when the weight average molecular weight of the thermoplastic resin used (A) is less than the lower limit of the above range and the NMP solution viscosity exceeds the upper limit of the above range, the polarity of the polymer becomes high. There is a tendency to have a high water absorption rate. (A) When the weight average molecular weight of the thermoplastic resin exceeds the upper limit of the above range and the viscosity of the NMP solution is less than the lower limit of the above range, the entanglement of the apparent polymer chain is large, but the molecular structure originates. Since intermolecular interaction (intermolecular interaction) is relatively weak, the physical properties (strength) at high temperatures tend to decrease.

(A) Thermoplastic resin is dimethylformamide, dimethylacetamide, NMP, dimethyl sulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone or acetic acid It is preferably soluble in an organic solvent such as ethyl.

(A) The thermoplastic resin is preferably a polyimide resin. A polyimide resin can be used individually by 1 type or in combination of 2 or more types as needed. The polyimide resin is obtained by subjecting tetracarboxylic dianhydride and diamine to a condensation reaction by an ordinary method, for example, in an organic solvent. The order of adding each component is arbitrary. Usually, the addition reaction is performed at 80 ° C. or less, preferably 0 to 60 ° C., and as the reaction proceeds, the viscosity of the reaction solution gradually increases, and polyamic acid which is a precursor of the polyimide resin is generated. The molecular weight may be adjusted by heating the produced polyamic acid at a temperature of 50 to 80 ° C. for depolymerization. This polyamic acid can be dehydrated and closed to obtain a polyimide resin. The dehydration ring closure can be performed by a thermal ring closure method in which heat treatment is performed or a chemical ring closure method using a dehydrating agent.

The composition ratio of the tetracarboxylic dianhydride and the diamine in the above condensation reaction may be equimolar, and if necessary, 0.5 to 2.2. The composition ratio may be adjusted in the range of 0 mol, preferably 0.8 to 1.0 mol. If the diamine exceeds 2.0 mol with respect to 1.0 mol of tetracarboxylic dianhydride, the amount of the polyimide oligomer having an amine terminal tends to increase in the obtained polyimide resin. There exists a tendency for the quantity of the polyimide oligomer which has an acid terminal to increase in the polyimide resin obtained as a diamine is less than 0.5 mol with respect to 1.0 mol of tetracarboxylic dianhydrides. In any case, the weight average molecular weight of the polyimide resin is lowered, and various characteristics including heat resistance of the adhesive layer tend to be lowered. Moreover, when the adhesive composition contains an epoxy resin having reactivity with these terminals, the storage stability of the adhesive composition tends to decrease as the amount of the polyimide oligomer increases. Such a tendency becomes more pronounced as the amount of amine-terminated polyimide oligomer increases.

The tetracarboxylic dianhydride is preferably purified by heat drying at a temperature lower than its melting point by 10 to 20 ° C. for 12 hours or more, or by recrystallization from acetic anhydride before the condensation reaction. . The difference between the endothermic onset temperature and the endothermic peak temperature by differential scanning calorimetry (DSC) of tetracarboxylic dianhydride is preferably within 10 ° C. The value of this temperature difference can be used as an index of the purity of tetracarboxylic dianhydride. The endothermic start temperature and endothermic peak temperature were measured using DSC (manufactured by PerkinElmer, Inc., DSC-7 type) under the conditions of sample amount: 5 mg, heating rate: 5 ° C./min, measurement atmosphere: nitrogen. Use the time value.

Examples of the tetracarboxylic dianhydride used as a raw material for the polyimide resin include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3. '-Biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1, 1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride Bis (3,4-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, (3,4-dicarboxyphenyl) ether dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,4,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 2 , 3,2 ′, 3′-benzophenone tetracarboxylic dianhydride, 3,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,4,5-naphthalenetetracarboxylic dianhydride, , 6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7 -Tetrachloronaphtha 1,4,5,8-tetracarboxylic dianhydride, phenanthrene-1,8,9,10-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride Thiophene-2,3,5,6-tetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,4,3 ′, 4′-biphenyltetracarboxylic acid Dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) dimethylsilane dianhydride, bis (3,4-dicarboxyphenyl) methylphenyl Silane dianhydride, bis (3,4-dicarboxyphenyl) diphenylsilane dianhydride, 1,4-bis (3,4-dicarboxyphenyldimethylsilyl) benzene dianhydride, 1,3-bis (3, 4- Dicarboxyphenyl) -1,1,3,3-tetramethyldicyclohexane dianhydride, p-phenylenebis (trimellitate anhydride), ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic Acid dianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2, 5,6-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, 1,2, 3,4-cyclobutanetetracarboxylic dianhydride, bis (exo-bicyclo [2,2,1] heptane-2,3-dicarboxylic dianhydride, bicyclo- [2,2,2] -oct-7- En-2, , 5,6-tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenyl) phenyl] Propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenyl) phenyl] hexafluoropropane dianhydride 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 1,4-bis (2-hydroxyhexafluoroisopropyl) benzenebis (trimellitic anhydride), 1,3- Bis (2-hydroxyhexafluoroisopropyl) benzenebis (trimellitic anhydride), 5- (2,5-dioxotetrahydrofuryl) -3-methyl 3-cyclohexene-1,2-dicarboxylic dianhydride, tetrahydrofuran-2,3,4,5-tetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 4,4 ′-(4 4′-isopropylidenediphenoxy) bis (phthalic dianhydride), 1,2- (ethylene) bis (trimellitic anhydride), 1,3- (trimethylene) bis (trimellitic anhydride), 1,4- ( Tetramethylene) bis (trimellitic anhydride), 1,5- (pentamethylene) bis (trimellitic anhydride), 1,6- (hexamethylene) bis (trimellitic anhydride), 1,7- (heptamethylene) bis ( Trimellitate anhydride), 1,8- (octamethylene) bis (trimellitate anhydride), 1,9- (nonamethylene) bis (trimellitate anhydride), 1 , 10- (Decamethylene) bis (trimellitic anhydride), 1,12- (dodecamethylene) bis (trimellitic anhydride), 1,16- (hexadecamethylene) bis (trimellitic anhydride), 1,18- (octa One type or two or more types are selected from decamethylene) bis (trimellitate anhydride). Among these, 4,4′-oxydiphthalic dianhydride and 4,4 ′-(4,4′-isopropylidenediphenoxy) bis (phthalic dianhydride) are capable of imparting superior moisture resistance reliability. Are preferred. In addition, 1,10- (decamemethylene) bis (trimellitic anhydride), 1,12- (dodecamethylene) bis (trimellitate anhydride), 1,16- (hexadeca) can be imparted with superior thermal fluidity. Methylene) bis (trimellitate anhydride) and 1,18- (octadecamethylene) bis (trimellitate anhydride) are preferred.

Examples of the diamine used as a raw material for the polyimide resin include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, and 4,4′-diaminodiphenyl ether. 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, bis (4-amino-3,5-dimethylphenyl) methane, bis (4-amino-3,5- Diisopropylphenyl) methane, 3,3′-diaminodiphenyldifluoromethane, 3,4′-diaminodiphenyldifluoromethane, 4,4′-diaminodiphenyldifluoromethane, 3,3′-diaminodiphenylsulfone, 3,4′-diamino Diphenyl Lufone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ketone, 3,4 '-Diaminodiphenyl ketone, 4,4'-diaminodiphenyl ketone, 2,2-bis (3-aminophenyl) propane, 2,2'-(3,4'-diaminodiphenyl) propane, 2,2-bis ( 4-aminophenyl) propane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2- (3,4'-diaminodiphenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) Hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-amino) Enoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,3 ′-(1,4-phenylenebis (1-methylethylidene)) bisaniline, 3,4 ′-(1,4-phenylenebis) (1-methylethylidene)) bisaniline, 4,4 ′-(1,4-phenylenebis (1-methylethylidene)) bisaniline, 2,2-bis (4- (3-aminophenoxy) phenyl) propane, 2, 2-bis (4- (3-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, bis (4- (3-aminophenoxy) phenyl) Sulfide, bis (4- (4-aminophenoxy) phenyl) sulfide, bis (4- (3-aminophenoxy) phenyl) sulfone , Aromatic diamines such as bis (4- (4-aminophenoxy) phenyl) sulfone, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 3,5-diaminobenzoic acid, 1,3-bis (amino Methyl) cyclohexane, 2,2-bis (4-aminophenoxyphenyl) propane, 4,7,10-trioxatridecane-1,13-diamine, 4,9-dioxadecane-1,12-diamine, 2,4 -Diamino-6- (diallylamino-) 1,3,5-triazine (also known as N, N'-diallylmelamine), vinyldiaminotriazine, N, N'-bis (3-aminopropyl) ethylenediamine, N, N '-Bisaminopropyl-1,3-propylenediamine, N, N'-bisaminopropyl-1,4-butylenediamine, N- (3-aminopropyl Pills) 1,3-propanediamine, methyliminobispropylamine, lauryliminobispropylamine, 1,4- (bisaminopropyl) piperazine, and Jeffermin D-230, D-400, D manufactured by Sun Techno Chemical Co., Ltd. Fats such as polyoxyalkylene diamines such as -2000, D-4000, ED-600, ED-900, ED-2001, EDR-148, polyetheramine D-230, D-400, D-2000 manufactured by BASF Corporation Diamines, further 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8- Diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,1 -Aliphatic diamines such as diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, further 1,1,3,3-tetramethyl-1,3-bis (4-aminophenyl) disiloxane, 1,1,3,3-tetraphenoxy-1,3-bis (4-aminoethyl) disiloxane, 1,1,3,3-tetraphenyl-1,3-bis (2-aminoethyl) disiloxane, 1,1,3,3-tetraphenyl-1,3-bis (3-aminopropyl) disiloxane, 1,1,3,3-tetramethyl-1,3-bis (2-aminoethyl) disiloxane, 1,1,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane, 1,1,3,3-tetramethyl-1,3-bis (3-aminobutyl) disiloxane, 1,3-jime Til-1,3-dimethoxy-1,3-bis (4-aminobutyl) disiloxane, 1,1,3,3,5,5-hexamethyl-1,5-bis (4-aminophenyl) trisiloxane, 1,1,5,5-tetraphenyl-3,3-dimethyl-1,5-bis (3-aminopropyl) trisiloxane, 1,1,5,5-tetraphenyl-3,3-dimethoxy-1, 5-bis (4-aminobutyl) trisiloxane, 1,1,5,5-tetraphenyl-3,3-dimethoxy-1,5-bis (5-aminopentyl) trisiloxane, 1,1,5,5 -Tetramethyl-3,3-dimethoxy-1,5-bis (2-aminoethyl) trisiloxane, 1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis (4-amino) Butyl) trisiloxane, 1,1, , 5-Tetramethyl-3,3-dimethoxy-1,5-bis (5-aminopentyl) trisiloxane, 1,1,3,3,5,5-hexamethyl-1,5-bis (3-aminopropyl) ) Trisiloxane, 1,1,3,3,5,5-hexaethyl-1,5-bis (3-aminopropyl) trisiloxane, 1,1,3,3,5,5-hexapropyl-1,5 -Selected from siloxane diamines such as bis (3-aminopropyl) trisiloxane. These diamines can be used alone or in combination of two or more.

In order to set the Tg of the polyimide resin to 100 ° C. or lower, it is preferable to use an aliphatic diamine such as polyoxyalkylene diamine. The ratio of the aliphatic diamine to the total amount of diamine is preferably 1 to 80 mol%, and more preferably 5 to 60 mol%. If the ratio of the aliphatic diamine is less than 1 mol%, the effect of imparting low temperature sticking property and heat fluidity to the adhesive sheet tends to be reduced, and if it exceeds 80 mol%, the Tg of the polyimide resin is excessively low. Thus, there is a high possibility that the self-supporting property of the adhesive sheet is lowered.

Commercially available aliphatic diamines include, for example, Jeffamine, D-230, D-400, D-2000, D-4000, ED-600, ED-900, ED-2001, or EDR-148, manufactured by Sun Techno Chemical Co., Ltd. Polyoxyalkylene diamines such as polyetheramine D-230, D-400 or D-2000 manufactured by BASF Corporation may be mentioned.

The weight average molecular weight of the polyimide resin is preferably 10,000 to 150,000, more preferably 20,000 to 80,000.

収 め By keeping the weight average molecular weight within these numerical ranges, the strength, flexibility and tackiness of the adhesive layer become better. In addition, since appropriate heat fluidity can be obtained, it is possible to more sufficiently ensure good embedding property to the level difference of the adherend surface. When the weight average molecular weight of the polyimide resin is less than 10,000, the film formability of the adhesive composition tends to decrease, or the strength of the adhesive layer tends to decrease. When the weight average molecular weight of the polyimide resin exceeds 150,000, the thermal fluidity tends to gradually decrease, or the embedding property to the uneven surface of the adherend tends to decrease.

By setting the Tg and the weight average molecular weight of the polyimide resin within the above ranges, not only can the temperature for attaching the adhesive layer to the adherend be kept lower, but also when the semiconductor element is bonded and fixed to the support member The heating temperature (die bonding temperature) can also be lowered. As a result, an increase in warpage of the semiconductor element can be more significantly suppressed. When the support member is an organic substrate, rapid vaporization of moisture absorption by the organic substrate due to the heating temperature during die bonding can be suppressed, and foaming of the die bonding material layer due to vaporization can be suppressed.

(B) The thermosetting component is a component capable of forming a crosslinked structure by heating and curing the adhesive layer. The (B) thermosetting component includes (B1) a reactive plasticizer having an allyl group or an epoxy group, (B2) a compound having a styryl group, and (B3) a compound having a maleimide group. The components (B1), (B2), and (B3) need not be separate compounds. As a result, it is possible to impart a high degree of curability in the thermal history during assembly of semiconductor elements, low outgassing properties, and high elasticity at high temperatures, and highly compatible with thermal fluidity at the B stage and high elasticity at the C stage. it can.

(B1) A reactive plasticizer having an allyl group or an epoxy group is an modifier having an allyl group or an epoxy group and capable of lowering the heat flow temperature at the B stage of the resulting adhesive composition, or heat There is no particular limitation as long as it is a modifier that can reduce the melt viscosity at the time, but at 1 atm, its own heat melting temperature is preferably 70 ° C. or less, and is liquid at ordinary temperature (25 ° C.). It is more preferable. The plasticizer may be in the oligomer or polymer form as well as the monomer. In this case, the weight average molecular weight is preferably 20000 or less from the viewpoint of imparting higher thermal fluidity. The reactive plasticizer may be a compound containing both an allyl group and an epoxy group.

Examples of such a reactive plasticizer include diallyl bisphenol A, diallyl bisphenol A diglycidyl ether or a polycondensate thereof (polycondensate of allylated bisphenol A and epichlorohydrin), bisallyl nadiimide, diallyl phthalate or diallyl phthalate. Prepolymer, triallyl isocyanurate, allyl group-modified or allyl group-containing phenol novolak, 1,3-diallyl-5-glycidyl isocyanurate, 1-allyl-3,5-diglycidyl isocyanurate, monofunctional allyl glycidyl ether Glycidyl ether of bisphenol A type (or AD type, S type, F type), glycidyl ether of water-added bisphenol A type, ethylene oxide adduct bisphenol A type glycidyl ether, propylene oxide Adduct bisphenol A type glycidyl ether, phenol novolak resin glycidyl ether, dimer acid glycidyl ether, trifunctional (or tetrafunctional) glycidylamine, or epoxy group-containing liquid acrylic polymer . Also included is an epoxy resin which is liquid at 25 ° C. and 1 atm. These can be used individually by 1 type or in combination of 2 or more types.

Among these, diallyl bisphenol A diglycidyl, which is liquid at 25 ° C. and 1 atm, can achieve a high degree of compatibility between good heat fluidity at the B stage and suppression of heat flow at the C stage of the obtained adhesive composition. Ethers, polycondensates of allylated bisphenol A and epichlorohydrin, allyl group-modified or allyl group-containing phenol novolacs, and epoxy group-containing liquid acrylic polymers are preferably used. More preferably, the epoxy group-containing acrylic polymer has a Tg of −10 ° C. or lower and a weight average molecular weight of 10,000 or lower.

The content of the reactive plasticizer having (B1) allyl group or epoxy group in the adhesive composition is from the viewpoint of good thermal fluidity at the B stage, low outgassing property and heat resistance at the C stage. (A) The amount is preferably 1 to 1000 parts by mass, more preferably 5 to 500 parts by mass, and still more preferably 5 to 100 parts by mass with respect to 100 parts by mass of the thermoplastic resin. If the content is less than 1 part by mass, the effect of achieving the above characteristics tends to be small. If the content exceeds 1000 parts by mass, outgassing during heating increases, and the film formability and handleability gradually decrease. Tend to.

(B2) Examples of the compound having a styryl group include 1-t-butyl-4-vinylbenzene, 1-methyl-4-vinylbenzene, 1-octyl-4-vinylbenzene, 1,3,5-trimethyl- 2-vinylbenzene, 4-vinylbenzoic acid, 4-vinylaniline, 3-vinylaniline, 1,4-dimethyl-2-vinylbenzene, 1-methoxy-2-vinylbenzene, 1-methoxy-3-vinylbenzene, 1-methoxy-4-vinylbenzene, 1,3,5-trimethyl-2-vinylbenzene, 1-ethoxy-4-vinylbenzene, 1-nitro-3-vinylbenzene, 2-methoxy-4-vinylphenol, 1 -Vinylnaphthalene, 2-vinylnaphthalene, methyl 4-vinylbenzoate, methyl 2-vinylbenzoate, 1-methoxymethoxy-4- Nylbenzene, methyl 2-methoxy-4-vinylbenzoate, 2- (vinylphenoxy) tetrahydrofuran, 1- (1-ethoxyethoxy) -4-vinylbenzene, pt-butoxycarbonylmethoxy-4-vinylbenzene, t- Examples thereof include butyldimethoxy (4-vinylphenyl) silane, t-butyl 4-vinylbenzoate, 2- (4-vinylphenoxy) tetrahydro-2H-pyran, or an acrylic polymer having a styryl group in the side chain.

(B2) The compound having a styryl group may be a compound represented by the following general formula (I) or (II). These compounds can be used individually by 1 type or in combination of 2 or more types.

In the formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents —O—, —CH ₂ — or a divalent group represented by the following general formula (i), and R ³ represents — O—, —CH ₂ —, —S— or a divalent group represented by the following general formula (ii), wherein R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or Represents a phenyl group, k represents an integer of 1 to 8, and l represents an integer of 1 to 3. R ⁶ and R ^{7 in} formulas (i) and (ii) each independently represent a hydrogen atom, a linear alkyl group having 1 to 5 carbon atoms, or a phenyl group.

In the formula (II), R ⁸ represents a hydrogen atom or a methyl group, R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a linear alkyl group having 1 to 5 carbon atoms or a phenyl group, and R ¹¹ represents —O—, —CH ₂ — or a divalent group represented by the following general formula (iii) is represented, and R ¹² represents —O—, —CH ₂ —, —S— or the following general formula (iv). R ¹³ and R ¹⁴ each independently represents a hydrogen atom, a linear alkyl group having 1 to 5 carbon atoms or a phenyl group, m represents an integer of 1 to 8, n Represents an integer of 1 to 3. R ¹⁵ and R ¹⁶ in the formulas (iii) and (iv) each independently represent a hydrogen atom, a linear alkyl group having 1 to 5 carbon atoms, or a phenyl group.

(B2) The compound having a styryl group preferably has two or more vinyl groups bonded to the aromatic ring. Examples of such a compound include 1,3-divinylbenzene, 1,4-divinylbenzene, 1,3-isopropenylbenzene, and a compound represented by the following general formula (III). In the formula (III), R ¹⁷ represents an aromatic ether oligomer chain, and R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom or a methyl group.

The compound represented by the formula (III) can be synthesized, for example, by reacting a compound having a chloroalkyl group and a styryl group with an aromatic ether oligomer. Aromatic ether oligomers include oligo (2,6-dimethylphenylene-1,4-ether), oligo (2-methyl-6-ethylphenylene-1,4-ether), oligo (2,6-diethylphenylene- 1,4-ether), oligo (2,6-dichlorophenylene-1,4-ether), oligo (2-chloro-6-methylphenylene-1,4-ether), oligo (2-phenylphenylene-1) , 4-ether), oligo (2-methyl-6-n-propylphenylene-1,4-ether), oligo (5-methylphenylene-1,3-ether), or oligo (phenylene-1,3-ether) And the like. Examples of the compound represented by the formula (III) include 2,2 ′, 3,3 ′, 5,5′-hexamethylbiphenyl-4,4′-diol, represented by the following general formula (IV): , 6-dimethylphenol polycondensate and a reaction product of chloromethylstyrene. These compounds are used alone or in combination. Among these, it is preferable that an adhesive composition contains the acrylic polymer which has a styryl group in a side chain. The adhesive composition contains an acrylic polymer having a styryl group in the side chain, so it has low outgas properties at the B stage, curability in the heat history received in the semiconductor device assembly process, high elasticity at high temperatures, and moisture resistance And high-temperature adhesiveness can be imparted to a higher degree.

　式（ＩＶ）中、ｐ及びｑはそれぞれ独立に１～５０の整数を示す。

In formula (IV), p and q each independently represents an integer of 1 to 50.

The amount of the compound having (B2) styryl group contained in the adhesive composition is low-temperature sticking property, low-temperature adhesive property and low outgas property in the B stage, curability in the thermal history received in the semiconductor device assembly process, C (A) It is 1 to 500 parts by mass with respect to 100 parts by mass of the thermoplastic resin in order to achieve a high degree of compatibility with high elasticity at high temperature, high temperature adhesiveness, heat resistance and moisture resistance at the stage. It is preferably 5 to 200 parts by mass, more preferably 5 to 100 parts by mass. If this content is less than 1 part by mass, the effect of achieving the above-mentioned characteristics tends to be small, and if it exceeds 500 parts by mass, the tendency for thermal fluidity to decrease and the film formability and handleability gradually increase. There is a tendency to decrease.

The compound having (B3) maleimide group preferably contains two or more maleimide groups, and a bismaleimide compound represented by the following general formula (V) and a novolac maleimide represented by the following general formula (VI) More preferably, it is at least one selected from compounds.

In the formula (V), R ²⁰ represents a divalent organic group containing an aromatic ring and / or a linear, branched or cyclic aliphatic hydrocarbon group. R ²⁰ is preferably a divalent group composed of a benzene residue, a toluene residue, a xylene residue, a naphthalene residue, a linear, branched or cyclic saturated hydrocarbon group, or a combination thereof. Is preferred. In the formula (VI), r represents an integer of 0 to 20.

R ²⁰ is a divalent group represented by the following formula (v), (vi) or (vii) in that the heat resistance and high-temperature adhesive strength at the C stage of the adhesive composition can be imparted to a higher degree. It is preferable. From the same viewpoint, the novolac maleimide compound of the above formula (VI) is also preferable.

The amount of the compound having a maleimide group (B3) contained in the adhesive composition is film forming property, low outgassing property at B stage, high elasticity at high temperature at C stage, high adhesiveness at high temperature, heat resistance In view of properties, (A) the amount is preferably 1 to 500 parts by weight, more preferably 5 to 200 parts by weight, and more preferably 5 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Further preferred. When the content is less than 1 part by mass, the effect of improving the above characteristics tends to be small. When the content exceeds 500 parts by mass, outgassing during heating tends to increase, and the film formability and handleability gradually increase. While decreasing, the strength of the adhesive layer after curing tends to decrease. (B2) A compound having a styryl group and (B3) a compound having a maleimide group can be used singly or in combination of two or more.

In order to promote curing by heating of a thermosetting component including (B2) a compound having a styryl group and (B3) a compound having a maleimide group, an organic peroxide is contained in the adhesive composition as necessary. May be. It is preferable to use an organic peroxide having a one-minute half-life temperature of 120 ° C. or higher from the viewpoint of suppressing the curing during the preparation of the adhesive sheet and storage stability at the B stage. The content of the organic peroxide contained in the adhesive composition is from 0.01 to 100 parts by weight with respect to 100 parts by weight of the compound having a maleimide group (B3) from the viewpoints of storage stability, low outgassing property, and curability. It is preferably 10 parts by mass.

The amount of the thermosetting component (B) contained in the adhesive composition is preferably 1 to 500 parts by weight and preferably 5 to 200 parts by weight with respect to 100 parts by weight of the (A) thermoplastic resin. Is more preferably 5 to 120 parts by mass. When this content exceeds 500 parts by mass, outgassing during heating increases and the film formability (toughness) tends to gradually decrease. If the content is less than 1 part by mass, the effect of imparting heat fluidity at the B stage, heat resistance and high temperature adhesiveness at the C stage tends to be reduced.

The adhesive composition may contain a curing agent and / or a curing accelerator (catalyst) in addition to the organic peroxide described above for curing the (B) thermosetting component. If necessary, a curing agent and a curing accelerator, or a catalyst and a promoter can be used in combination. About the addition amount of the said hardening | curing agent, hardening accelerator, a catalyst, a co-catalyst, and an organic peroxide, and the presence or absence of addition, in the range which can ensure the desired heat fluidity | liquidity mentioned later, sclerosis | hardenability, and the heat resistance after hardening | curing. Judge and adjust.

(B) The thermosetting component preferably includes (B4) a solid epoxy resin at 25 ° C. and 1 atm as the thermosetting resin. Solid epoxy resins tend to have a relatively large molecular weight and a large number of functional groups compared to liquid epoxy resins, so that the crosslink density after curing is high, and the low-temperature sticking property and reflow resistance are further improved. improves. Such an epoxy resin is more preferably solid at 25 ° C. containing at least two epoxy groups in the molecule, and is a phenol glycidyl ether type epoxy resin from the viewpoint of curability and cured product characteristics. Is very preferred. In particular, when a polyimide resin is used as the thermoplastic resin, the crosslinking density is synergistically improved by the thermal reaction between the reactive group such as acid or amine contained in the oligomer terminal group of the polyimide resin and the epoxy group. By improving the crosslinking density, the effect of imparting higher curability and increasing the elastic modulus due to the thermal history received in the assembly process is further enhanced, and higher low-temperature sticking properties and reflow resistance can be obtained. In addition, the compound applicable to the reactive plasticizer which has (B1) epoxy group shall not be contained in (B4) solid epoxy resin at 25 degreeC and 1 atm. As such an epoxy resin, for example, glycidyl ether of bisphenol A type (or AD type, S type, F type), glycidyl ether of water-added bisphenol A type, ethylene oxide adduct bisphenol A type glycidyl ether, propylene oxide addition Bisphenol A type glycidyl ether, phenol novolak resin glycidyl ether, cresol novolak resin glycidyl ether, bisphenol A novolak resin glycidyl ether, naphthalene resin glycidyl ether, diallyl bisphenol A diglycidyl ether or polycondensate thereof, trisphenol Trifunctional (or tetrafunctional) glycidyl ether such as methane type, glycidyl ether of dicyclopentadienephenol resin, dimer acid group Glycidyl ester, 3 glycidylamine functional type (or tetrafunctional), or glycidyl amines of naphthalene resins. These can be used individually by 1 type or in combination of 2 or more types.

Epoxy resin is a high-purity product in which impurity ions such as alkali metal ions, alkaline earth metal ions, halogen ions, particularly chlorine ions and hydrolyzable chlorine are reduced to 300 ppm or less to prevent electromigration and metal This is preferable for preventing corrosion of the conductor circuit.

If necessary, an epoxy resin curing agent can be used in combination with an epoxy resin. Examples of the curing agent include phenolic compounds, aliphatic amines, alicyclic amines, aromatic polyamines, polyamides, aliphatic acid anhydrides, alicyclic acid anhydrides, aromatic acid anhydrides, dicyandiamide, and organic acid dihydrazides. , Boron trifluoride amine complexes, imidazoles, or tertiary amines. Among these, phenol compounds are preferable, and phenol compounds having at least two phenolic hydroxyl groups in the molecule are more preferable. Examples of such compounds include phenol novolak resins, cresol novolak resins, t-butylphenol novolak resins, dicyclopentadiene cresol novolak resins, dicyclopentadiene phenol novolak resins, xylylene-modified phenol novolak resins, naphthol compounds, trisphenol compounds. Tetrakisphenol novolak resin, bisphenol A novolak resin, poly-p-vinylphenol resin, phenol aralkyl resin and the like. Among these, those having a number average molecular weight in the range of 400 to 1500 are preferable. By using these curing agents, it is possible to further reduce outgas, which causes contamination of semiconductor elements or devices, during heating in the semiconductor device assembly process. In order to secure the heat resistance of the cured product, the compounding amount of these phenolic compounds is such that the equivalent ratio of the epoxy equivalent of the epoxy resin and the OH equivalent of the phenolic compound is 0.95: 1.05. It is preferable to adjust so as to be ˜1.05: 0.95.

If necessary, a curing accelerator can also be used. The curing accelerator is not particularly limited as long as it can cure a thermosetting resin. For example, imidazoles, dicyandiamide derivatives, dicarboxylic acid dihydrazide, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, 2-ethyl-4 -Methylimidazole-tetraphenylborate or 1,8-diazabicyclo [5.4.0] undecene-7-tetraphenylborate.

The adhesive composition preferably further contains (C) a filler. When the adhesive composition further contains (C) filler, in particular, it is possible to achieve a high degree of easy cutting property during dicing, easy peeling from the dicing tape during pick-up, and reflow resistance. Moreover, it can contribute to the improvement of the elastic modulus due to the thermal history received in the assembly process, the low hygroscopicity, and the improvement of the breaking strength in the reflow process.

Examples of the filler include metal fillers such as silver powder, gold powder, copper powder, and nickel powder; alumina, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, Examples thereof include non-metallic inorganic fillers such as aluminum oxide, aluminum nitride, crystalline silica, amorphous silica, boron nitride, titania, glass, iron oxide, and ceramic; or organic fillers such as carbon and rubber fillers. Regardless of the type and shape, the filler can be used without any particular limitation.

(C) The filler can be used properly according to the desired function. For example, a metal filler is added to the adhesive composition for the purpose of improving conductivity, thermal conductivity, thixotropy, etc., and a non-metallic inorganic filler is added to the adhesive layer for thermal conductivity, low thermal expansion, and low hygroscopicity. The organic filler is added to the adhesive layer for the purpose of improving toughness and the like. These metal fillers, non-metallic inorganic fillers, or organic fillers can be used alone or in combination of two or more. Among these, a metal filler, a non-metallic inorganic filler, or an insulating filler is preferable in terms of improving the conductivity, thermal conductivity, low moisture absorption characteristics, insulation, and the like required for an adhesive material for a semiconductor device. Among metal inorganic fillers or insulating fillers, boron nitride fillers or silica fillers are more preferable in that they have good dispersibility with respect to the resin varnish and can improve the adhesive strength at high temperatures.

The amount of (C) filler contained in the adhesive composition is determined according to the characteristics or functions to be improved. (C) Filler content is the total of (A) thermoplastic resin, (B) thermosetting component, (C) filler, coupling agent, ion supplement and other additives in the adhesive composition. Is preferably 1 to 40% by volume, more preferably 5 to 30% by volume, and still more preferably 5 to 20% by volume. (C) By appropriately increasing the amount of filler, the sheet surface can be reduced in adhesion and increased in elastic modulus, dicing properties (cutability with a dicer blade), pick-up properties (easy peeling from dicing tape), wire Bondability (ultrasonic efficiency) and adhesive strength during heating can be improved to a higher degree. (C) If the filler is increased more than necessary, the effects relating to low-temperature sticking property, interfacial adhesion with the adherend, and heat fluidity may be reduced, and reliability including reflow resistance may be reduced. . Therefore, it is preferable that the content of the (C) filler is within the above range. It is preferable to determine the optimum content in order to balance the required characteristics. (C) Mixing and kneading in the case of using a filler can be performed by appropriately combining dispersers such as a normal stirrer, a raking machine, a triple roll, and a ball mill.

In the adhesive composition, various coupling agents can be added in order to improve interfacial bonding between different materials. Examples of the coupling agent include silane-based, titanium-based, and aluminum-based. Among them, a silane-based coupling agent is preferable because it is highly effective. The amount of the coupling agent used is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic resin from the viewpoint of the effect, heat resistance, and cost.

In the adhesive composition, an ion scavenger can be further added in order to adsorb ionic impurities and improve insulation reliability during moisture absorption. Such an ion scavenger is not particularly limited. For example, a triazine thiol compound, a compound known as a copper damage preventer for preventing copper from being ionized and dissolved, such as a bisphenol-based reducing agent, a zirconium-based compound Or inorganic ion adsorbents such as antimony bismuth-based magnesium aluminum compounds. The use amount of the ion scavenger is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the thermoplastic resin from the viewpoint of the effect of addition, heat resistance, cost, and the like.

As the other additive, a tackifier such as a softener, an anti-aging agent, a colorant, a flame retardant, and a terpene resin may be appropriately added to the adhesive composition.

The adhesive sheet according to the present embodiment is formed by, for example, applying a varnish obtained by dissolving or dispersing an adhesive composition in an organic solvent on a substrate, and heating and drying the applied varnish to form an adhesive layer. It can manufacture by the method to do (solvent casting method). After the formation of the adhesive layer, the substrate may be removed, or the substrate may be used as it is as a support film for the adhesive sheet. The conditions for heat drying are not particularly limited as long as the organic solvent (solvent) in the varnish is sufficiently volatilized, but is usually 50 to 200 ° C. and about 0.1 to 90 minutes. The heating condition may be divided into two or more stages.

The varnish used for forming the adhesive layer is prepared by a method in which the above-mentioned components constituting the adhesive composition are mixed in an organic solvent, and the mixture is kneaded as necessary. Mixing and kneading for preparing the varnish can be performed by appropriately combining dispersers such as a normal stirrer, a raking machine, a triple roll, and a ball mill.

The organic solvent used in the varnish is not particularly limited as long as each component can be uniformly dissolved or dispersed. For example, dimethylformamide, dimethylacetamide, NMP, dimethyl sulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, It is selected from methyl isobutyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone and ethyl acetate.

The substrate (support film 2) used for forming the adhesive layer is not particularly limited as long as it can withstand the above heating and drying conditions. For example, a polyester film, a polypropylene film, a polyethylene terephthalate film, a polyimide film, a polyetherimide film, a polyether naphthalate film, or a methylpentene film is used. These base film may be a multilayer film in which two or more kinds are combined, or the surface may be treated with a release agent such as silicone or silica.

FIG. 4 is a cross-sectional view showing an embodiment of a dicing / die bonding integrated adhesive sheet including a dicing sheet. An adhesive sheet 130 shown in FIG. 4 includes a base film 7 and a dicing sheet 5 having an adhesive layer 6 provided on the base film, and a film-like adhesive provided on the adhesive layer 6 of the dicing sheet. It is a laminate composed of the layer 1. The adhesive sheet shown in FIG. 4 has characteristics required for both the dicing sheet and the die bonding film. The base film 7 used in the adhesive sheet 130 of FIG. 4 is usually the same as the support film 2 described above.

The adhesive layer 1 of the adhesive sheet 130 in FIG. 4 is preferably preliminarily formed (pre-cut) in a shape close to that of the semiconductor wafer to which the adhesive layer 1 is attached.

The pressure-sensitive adhesive layer 6 is formed of a pressure-sensitive or radiation-curable pressure-sensitive adhesive. The pressure-sensitive adhesive layer 6 has a sufficient adhesive strength so that the semiconductor element does not scatter during dicing, and has a low adhesive strength that does not damage the semiconductor element in the subsequent pick-up process of the semiconductor element. You can use what you have. For example, a radiation curable pressure-sensitive adhesive has a high adhesive strength during dicing, and its adhesive strength is reduced by radiation before pick-up when picking up after dicing.

Instead of using a dicing sheet having an adhesive layer as in the adhesive sheet 140 of FIG. 5, a base film 7 having a function as a dicing sheet can also be used. The base film 7 used in the adhesive sheet 140 of FIG. 5 can ensure elongation (so-called “expand”) when tensile tension is applied. As the base film 7, for example, a polyolefin film is preferably used.

The adhesive sheets 130 and 140 shown in FIGS. 4 and 5 function as a dicing sheet during dicing and as a die bonding film during die bonding. Therefore, after laminating and dicing the adhesive layer 1 of these adhesive sheets on the back surface of the semiconductor wafer while heating, the semiconductor element with the adhesive layer attached can be picked up and die bonded. it can.

The adhesive composition and the adhesive sheet according to the present embodiment described above are extremely useful as an adhesive for fixing a semiconductor element for adhering a semiconductor element such as an IC or LSI to another adherend, in other words, as an adhesive for die bonding. It is.

The adherend to which the semiconductor element is bonded includes a lead frame such as a 42 alloy lead frame or a copper lead frame; a plastic film such as a polyimide resin or an epoxy resin; and a plastic such as a polyimide resin or an epoxy resin on a substrate such as a glass nonwoven fabric. Impregnated and hardened; semiconductor element mounting support members such as ceramics such as alumina. Among them, an adhesive sheet is suitable as an adhesive material for die bonding for bonding an organic substrate having an organic resist layer on the surface, an organic substrate having wiring on the surface, etc., and an organic substrate having irregularities on the surface and a semiconductor element. Used for.

An adhesive composition and an adhesive sheet according to the present embodiment include a semiconductor element fixing adhesive used for bonding adjacent semiconductor elements in a semiconductor device (Stacked-PKG) having a structure in which a plurality of semiconductor elements are stacked. Also preferably used.

Next, in connection with the use of the adhesive composition according to the present embodiment, embodiments of the semiconductor element will be specifically described with reference to the drawings. In recent years, semiconductor devices having various structures have been proposed, and the use of the adhesive composition and the adhesive sheet of the present embodiment is not limited to the semiconductor devices having the structures described below.

FIG. 6 is a schematic cross-sectional view showing an embodiment of a semiconductor device. In the semiconductor device 200 shown in FIG. 6, the semiconductor element 9 is bonded to the support member 10 via the die bonding layer (cured adhesive layer) 8 formed of the above-described adhesive composition, and the connection of the semiconductor element 9 is performed. A terminal (not shown) is electrically connected to an external connection terminal (not shown) via a wire 11 and is further sealed with a sealing material 12.

FIG. 7 is a schematic cross-sectional view showing another embodiment of the semiconductor device. In the semiconductor device 210 shown in FIG. 7, the first-stage semiconductor element 9a is bonded to the support member 10 on which the terminals 13 are formed via the die bonding layer (cured adhesive layer) 8 formed by the adhesive composition. The semiconductor element 9b is bonded to the semiconductor element 9a via the die bonding layer (cured adhesive layer) 8 formed of the adhesive composition, and the whole is sealed with the sealing material 12. have. Connection terminals (not shown) of the semiconductor element 9a and the semiconductor element 9b are electrically connected to external connection terminals via wires 11, respectively.

The semiconductor device (semiconductor package) shown in FIGS. 6 and 7 has a film-like adhesive layer sandwiched between a semiconductor element and a supporting member and / or the semiconductor elements, and bonded by thermocompression bonding. After that, it can be manufactured through a wire bonding step and, if necessary, a step such as a sealing step with a sealing material. The heating temperature in the thermocompression bonding step is usually 20 to 250 ° C., the load is usually 0.01 to 20 kgf, and the heating time is usually 0.1 to 300 seconds.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples of the present invention. However, the present invention is not limited to these examples, and various modifications can be made without departing from the technical idea of the present invention. Can be changed. In addition, the numerical value in a table | surface is a mass reference | standard (mass part) unless there is particular notice.

[Synthesis of polyimide resin (PI-1)]
1,3-bis (3-aminopropyl) tetramethyldisiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: LP-7100) in a 300 mL flask equipped with a thermometer, stirrer, condenser, and nitrogen inlet pipe 15.53 g, 28.13 g of polyoxypropylenediamine (manufactured by BASF Corporation, trade name: D400, molecular weight: 450) and NMP 100.0 g were charged and stirred to prepare a reaction solution. After the diamine was dissolved, 32.30 g of 4,4′-oxydiphthalic dianhydride previously purified by recrystallization from acetic anhydride was added to the reaction solution little by little while the flask was cooled in an ice bath. After reacting at room temperature (25 ° C.) for 8 hours, 67.0 g of xylene was added and heated at 180 ° C. while blowing nitrogen gas to azeotropically remove xylene together with water. The reaction solution was poured into a large amount of water, and the precipitated resin was collected by filtration and dried to obtain a polyimide resin (PI-1). When the molecular weight of the obtained polyimide resin (PI-1) was measured by GPC, it was number average molecular weight Mn = 22400 and weight average molecular weight Mw = 70200 in terms of polystyrene. The Tg of the polyimide resin (PI-1) was 45 ° C. Moreover, the viscosity at 25 ° C. of a resin solution dissolved in NMP with a resin content of 25% by mass was 10 poise.

[Synthesis of polyimide resin (PI-2)]
In a 300 mL flask equipped with a thermometer, stirrer, condenser, and nitrogen inlet tube, 13.68 g of 2,2-bis (4-aminophenoxyphenyl) propane, 4,9-dioxadecane-1,12-diamine 6. 80 g and 165.8 g of NMP were charged and stirred to prepare a reaction solution. After the diamine was dissolved, 34.80 g of decamethylene bistrimellitate dianhydride previously purified by recrystallization from acetic anhydride was added to the reaction solution little by little while the flask was cooled in an ice bath. After reacting at room temperature (25 ° C.) for 8 hours, 110.5 g of xylene was added, and heated at 180 ° C. while blowing nitrogen gas to azeotropically remove xylene together with water. The reaction solution was poured into a large amount of water, and the precipitated resin was collected by filtration and dried to obtain a polyimide resin (PI-2). When the molecular weight of the obtained polyimide resin (PI-2) was measured by GPC, it was number average molecular weight Mn = 28900 and weight average molecular weight Mw = 88600 in terms of polystyrene. The Tg of the polyimide resin (PI-2) was 67 ° C. Further, the viscosity at 25 ° C. of a resin solution dissolved in NMP with a resin content of 25% by mass was 150 poise.

[Synthesis of polyimide resin (PI-3)]
In a 300 mL flask equipped with a thermometer, a stirrer, a condenser tube, and a nitrogen inflow tube, 27.30 g of 2,2-bis (4-aminophenoxyphenyl) propane and 248.4 g of NMP were charged and stirred to react. A liquid was prepared. After the diamine was dissolved, 34.80 g of decamethylene bistrimellitate dianhydride previously purified by recrystallization from acetic anhydride was added to the reaction solution little by little while the flask was cooled in an ice bath. After reacting at room temperature (25 ° C.) for 8 hours, 165.6 g of xylene was added and heated at 180 ° C. while blowing nitrogen gas, thereby azeotropically removing xylene together with water. The reaction solution was poured into a large amount of water, and the precipitated resin was collected by filtration and dried to obtain a polyimide resin (PI-3). When the molecular weight of the obtained polyimide resin (PI-3) was measured by GPC, it was number average molecular weight Mn = 23200 and weight average molecular weight Mw = 89400 in terms of polystyrene. The Tg of the polyimide resin (PI-3) was 120 ° C. The viscosity at 25 ° C. of the resin solution dissolved in NMP with a resin content of 25% by mass was 205 poise.

[Synthesis of polyimide resin (PI-4)]
In a 300 mL flask equipped with a thermometer, a stirrer, a condenser tube, and a nitrogen inflow tube, 27.30 g of 2,2-bis (4-aminophenoxyphenyl) propane and 248.4 g of NMP were charged and stirred to react. A liquid was prepared. After the diamine was dissolved, 34.80 g of decamethylene bistrimellitate dianhydride previously purified by recrystallization from acetic anhydride was added to the reaction solution little by little while the flask was cooled in an ice bath. After reacting at room temperature (25 ° C.) for 8 hours, 165.6 g of xylene was added, and the reaction was carried out at 180 ° C. with blowing nitrogen gas for a longer time than in the case of the polyimide resin (PI-3). Was removed azeotropically. The reaction solution was poured into a large amount of water, and the precipitated resin was collected by filtration and dried to obtain a polyimide resin (PI-4). When the molecular weight of the obtained polyimide resin (PI-4) was measured by GPC, it was number average molecular weight Mn = 22800 and weight average molecular weight Mw = 189600 in terms of polystyrene. The Tg of the polyimide resin (PI-4) was 120 ° C. The viscosity at 25 ° C. of a resin solution dissolved in NMP with a resin content of 25% by mass was 420 poise.

[Preparation of adhesive composition (varnish)]
Using the polyimide resins (PI-1) to (PI-4) obtained above, each component was blended in the composition ratio (unit: part by mass) of each Example and Comparative Example shown in Table 1 and Table 2. A varnish for forming an adhesive layer was obtained.

In addition, the symbol of each component in Table 1 and Table 2 means the following.
<Thermoplastic resin other than polyimide resin>
“PVB-1”: Polyvinyl butyral resin (SB-45M, Tg: 76 ° C., weight average molecular weight: 82000, resin content 25% by mass, solution viscosity at 25 ° C. of a resin solution manufactured by Kuraray Co., Ltd .: 180 poise)
“PVB-2”: Polyvinyl butyral resin (Butvar-72, Tg: 75 ° C., weight average molecular weight: 210000, resin content 25% by mass, solution viscosity at 25 ° C., manufactured by Solusia Co., Ltd .: > 500 poise)
“ZX-1395”: manufactured by Tohto Kasei Co., Ltd., phenoxy resin (Tg: 68 ° C., weight average molecular weight: 88,000, resin viscosity of 25% by mass of resin solution dissolved in NMP at 25 ° C .: 3 poise)
<Reactive plasticizer>
"RE-810NM": Nippon Kayaku Co., Ltd. diallyl bisphenol A diglycidyl ether (property: liquid)
“UG-4010”: Epoxy group-containing solvent-free liquid acrylic polymer (ARUFON, Tg: −57 ° C., weight average molecular weight: 2900), manufactured by Toagosei Co., Ltd.
“MEH-8010”: Meiwa Kasei Co., Ltd., partially allyl group-modified phenol novolak resin (property: liquid)
“N730”: phenol novolac type liquid epoxy resin (N-730-S) manufactured by DIC Corporation
“DA-MGIC”: diallyl monoglycidyl isocyanuric acid manufactured by Shikoku Kasei Kogyo Co., Ltd. (property: solid, melting point: 40 ° C.)
<Compound having styryl group>
“OPE-2St”: manufactured by Mitsubishi Gas Chemical Co., Ltd., 2,2 ′, 3,3 ′, 5,5′-hexamethylbiphenyl-4,4′-diol · 2,6-dimethylphenol polycondensate, Reaction product with chloromethylstyrene (number average molecular weight: 1200)
“Foret SCS”: manufactured by Soken Chemical Co., Ltd., styryl group-containing acrylic polymer (Tg: 70 ° C., weight average molecular weight: 15000)
<Compound having a maleimide group>
“BMI-1”: manufactured by Tokyo Chemical Industry Co., Ltd., 4,4′-bismaleimide diphenylmethane “BMI-2”: manufactured by Kay Kasei Chemical Co., Ltd., 2,2′-bis- [4- (4-maleimidephenoxy) Phenyl] propane (BMI-80)
<Epoxy resin solid at 25 ° C. and 1 atm>
“ESCN-195”: manufactured by Sumitomo Chemical Co., Ltd., cresol novolac type solid epoxy resin (epoxy equivalent: 200)
<Curing agent for epoxy resin>
“HP-850N”: manufactured by Hitachi Chemical Co., Ltd., phenol novolac resin (OH equivalent: 106, property: solid)
<Curing accelerator for epoxy resin>
“TPPK”: manufactured by Tokyo Chemical Industry Co., Ltd., tetraphenylphosphonium tetraphenylborate <filler>
“HP-P1”: manufactured by Mizushima Alloy Iron Co., Ltd., boron nitride filler <solvent>
“NMP”: manufactured by Kanto Chemical Co., Inc., N-methyl-2-pyrrolidone

[Preparation of adhesive sheet]
The obtained varnish was apply | coated on the support film so that the film thickness after drying might be set to 40 micrometers +/- 5micrometer. A biaxially stretched polypropylene (OPP) film (thickness 60 μm) was used as the support film. The coated varnish is dried by heating in an oven at 80 ° C. for 30 minutes and then at 120 ° C. for 30 minutes to have a support film and a film-like adhesive layer formed on the support film An adhesive sheet was obtained.

[Evaluation of thin film formability]
About the adhesive sheet obtained on the said conditions, the film formability was evaluated by the following references | standards. When the film forming property evaluation is A based on the following criteria, it means that the thin film forming property is excellent.
A: The film-like adhesive layer can be applied without repelling on the supporting substrate, the supporting substrate can be peeled from the obtained adhesive sheet, and the adhesive layer is cracked after peeling the supporting substrate. C: There is repellency of the film-like adhesive layer on the supporting substrate, or cracking of the adhesive layer occurs (brittle) when the supporting substrate is peeled from the obtained adhesive sheet

[Evaluation of low temperature adhesiveness]
A test piece having a width of 10 mm and a length of 40 mm was cut out from each adhesive sheet obtained in Examples and Comparative Examples. This test piece was laminated on the back surface (surface opposite to the support table) of the silicon wafer (6 inch diameter, thickness 400 μm) placed on the support table so that the adhesive layer was on the silicon wafer side. Lamination was performed by a method of pressurizing with a roll (temperature 100 ° C., linear pressure 4 kgf / cm, feed rate 0.5 m / min).

The sample thus prepared was subjected to a 90 ° peel test at room temperature using a rheometer (“Torograph ES” (trade name) manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the adhesive layer-silicon wafer The peel strength was measured. From the measurement results, the low temperature sticking property was evaluated according to the following criteria.
A: Peel strength is 2 N / cm or more C: Peel strength is less than 2 N / cm

[Measurement of flow amount]
The adhesive sheet obtained by forming each film-like adhesive layer in a B-stage state with a thickness of 40 μm on an OPP base material with a thickness of 60 μm obtained in each example and each comparative example was cut into a size of 10 mm × 10 mm. A test piece was obtained. This test piece was sandwiched between two slide glasses (Matsunami Glass Industry Co., Ltd., 76 mm × 26 mm × 1.0 to 1.2 mm thickness), and 100 kgf / cm ² overall on a 120 ° C. hot platen. The pressure bonding was performed for 15 seconds while applying a load. The amount of protrusion of the film adhesive from the four sides of the OPP substrate after thermocompression bonding was measured with an optical microscope, and the average value thereof was taken as the flow amount. The B stage refers to the state after the adhesive layer forming varnish is coated on the OPP substrate and then heated in an oven at 80 ° C. for 30 minutes and then at 120 ° C. for 30 minutes. It is. The larger the value of this flow amount, the better the thermal fluidity at the B stage and the better the filling property (embedding property) for the irregularities on the adherend surface.

[Measurement of 260 ° C peel strength]
The adhesive layer (5 mm × 5 mm × 40 μm thickness) of each adhesive sheet obtained in the examples and comparative examples is placed between a 42 alloy lead frame and a silicon chip having a protrusion (5 mm × 5 mm × 400 μm thickness). It was interposed and heat-pressed in that state. The heating temperature was set to 150 ° C. for Examples 1 to 5, Example 7, Comparative Examples 1 to 3 and Comparative Example 6, and 180 ° C. for Example 6 and Comparative Examples 4 and 5. The pressurization was performed under the conditions of load: 1 kgf / chip, time: 5 seconds. After thermocompression bonding, the adhesive layer was cured by heating in an oven at 150 ° C. for 1 hour or 180 ° C. for 5 hours to obtain a laminate as a sample for measuring peel strength.

The 260 ° C. peel strength was measured using the adhesive strength evaluation apparatus shown in FIG. The adhesive force evaluation apparatus 300 shown in FIG. A handle 32 is provided at a tip end of a rod attached to the push-pull gauge 31 so as to have a variable angle around a fulcrum 33.

A laminated body in which the silicon wafer 9 and the 42 alloy lead frame 35 are bonded to each other on the heated platen 36 heated to 260 ° C. via the cured adhesive layer 8 is bonded to the 42 alloy lead frame 35 on the hot platen 36 side. And the sample was heated for 20 seconds. Next, with the handle 32 hooked on the protrusion of the silicon wafer 9, the handle 32 is moved at a rate of 0.5 mm / second in a direction parallel to the main surface of the sample, and the peeling stress of the silicon wafer 9 at that time is push-pull. Measurement was performed with a gauge 31. The measured peel stress was defined as 260 ° C. peel strength. The greater the peel strength, the better the reflow resistance and the higher the reliability of the semiconductor device. In addition, a high peel strength in a sample obtained under a lower heating condition such as 150 ° C. means that the curability is excellent in the heat history received in the assembly process such as wire bonding.

The adhesive layer was heat-cured for 5 hours at 180 ° C. in an oven for the sample heat-pressed under the above conditions, and then left in a constant temperature and humidity chamber at 85 ° C. and 85% RH for 48 hours. Using the sample after the moisture absorption treatment, the 260 ° C. peel strength after moisture absorption was measured by the same method as described above.

As is apparent from the results shown in Tables 1 and 2, it was confirmed that the adhesive compositions of the examples were excellent in low-temperature sticking property and had a sufficiently high 260 ° C. peel strength after heat curing and moisture absorption. It was.

[Measurement of storage modulus]
After the adhesive layer forming varnish is applied on the OPP substrate, it is heated in an oven at 80 ° C. for 30 minutes, and then at 120 ° C. for 30 minutes. An agent layer was obtained. The obtained film-like adhesive layer was sandwiched between two frame-shaped iron frames, and the adhesive layer was heated and cured in an oven at 180 ° C. for 5 hours. A viscoelasticity analyzer (trade name: RSA-2, temperature increase rate: 5 ° C./min, frequency: frequency) for a test piece obtained by cutting a film-like adhesive layer after heat curing into a size of 35 mm × 10 mm. 1 Hz, measurement temperature: −150 to 300 ° C., mode: tensile mode), and the storage elastic modulus of the adhesive layer after heat curing at 150 ° C. and 260 ° C. was estimated. The high elastic modulus at these temperatures increases the ultrasonic efficiency at the time of wire bonding using an ultrathin chip, and increases the possibility of suppressing chip breakage due to an impact at the time of wire bonding. Moreover, it can contribute to the improvement of reflow resistance of the obtained semiconductor device.

Claims (14)

(A) Thermoplastic having a weight average molecular weight of 10,000 to 150,000 and a viscosity of 5 to 300 poise at 25 ° C. when dissolved in N-methyl-2-pyrrolidone so that the resin content is 25% by mass An adhesive composition containing a resin and (B) a thermosetting component,
The adhesive composition, wherein the (B) thermosetting component comprises (B1) a reactive plasticizer having an allyl group or an epoxy group, (B2) a compound having a styryl group, and (B3) a compound having a maleimide group. . The adhesive composition according to claim 1, wherein the reactive plasticizer having (B1) allyl group or epoxy group contains diallyl bisphenol A diglycidyl ether or a polycondensate of allylated bisphenol A and epichlorohydrin. The adhesive composition according to claim 1, wherein the reactive plasticizer having (B1) allyl group or epoxy group includes an epoxy group-containing liquid acrylic polymer. The adhesive composition according to claim 1, wherein the compound (B2) having a styryl group includes an acrylic polymer having a styryl group in a side chain. The adhesive composition according to any one of claims 1 to 4, wherein the (B) thermosetting component further comprises (B4) an epoxy resin that is solid at 25 ° C and 1 atm. The adhesive composition according to any one of claims 1 to 5, wherein the (A) thermoplastic resin has a glass transition temperature of 100 ° C or lower. The adhesive composition according to any one of claims 1 to 6, wherein the (A) thermoplastic resin is a polyimide resin. The adhesive composition according to any one of claims 1 to 7, further comprising (C) a filler. The adhesive composition according to any one of claims 1 to 8, which is used for fixing a semiconductor element. An adhesive sheet comprising an adhesive layer in which the adhesive composition according to any one of claims 1 to 8 is formed into a film shape. The adhesive sheet according to claim 10, further comprising a support film, wherein the adhesive layer is provided on the support film. The adhesive sheet according to claim 10, further comprising a dicing sheet, wherein the adhesive layer is provided on the dicing sheet. The adhesive sheet according to claim 12, wherein the dicing sheet has a base film and a pressure-sensitive adhesive layer provided on the base film, and the adhesive layer is provided on the pressure-sensitive adhesive layer. A semiconductor device comprising one or more semiconductor elements and a support member,
A semiconductor device in which the semiconductor element and the support member and / or the semiconductor elements are bonded together by the adhesive composition according to any one of claims 1 to 8.

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