JP2017165981A - Film-like adhesive and dicing die bonding integrated adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film-like adhesive exhibiting good connection credibility even with using thinned semiconductor element and a dicing die bonding integrated adhesive sheet.SOLUTION: In semiconductor device 200 by wire bonding connecting a first semiconductor element Wa onto a substrate 14 via a first wire 88 and crimping a second semiconductor element Waa having area larger than area of the first semiconductor element Wa on the first semiconductor element Wa, a film-like adhesive 10 is used for crimping the second semiconductor element Waa and imbedding the first wire 88 and the first semiconductor element Wa. In the film-like adhesive 10, elastic modulus at 50°C after curing is 1000 MPa or less, elastic modulus at 150°C to 260°C after curing is 20 MPa or less and glass transition temperature Tg is 150°C. The film-like adhesive 10 contains an epoxy resin and a phenol resin.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a film adhesive and a dicing die bonding integrated adhesive sheet.

  Stacked MCP (Multi Chip Package), in which semiconductor elements are stacked in multiple stages and increased in capacity with the increase in functionality of mobile phones and the like, has become widespread, and film-like bonding is advantageous in the mounting process for mounting semiconductor elements The agent is widely used as an adhesive for die bonding. An example of a multi-layer stacked package using such a film adhesive is a wire-embedded package. This is a package in which a wire connected to a semiconductor element to be crimped is crimped while being crimped using a high-fluid film adhesive. It is installed in memory packages for audio equipment.

  One of the important characteristics required for semiconductor devices such as the above-mentioned stacked MCP is connection reliability. In order to improve connection reliability, a film shape that takes into account characteristics such as heat resistance, moisture resistance, and reflow resistance Adhesives are being developed. As such a film adhesive, for example, Patent Document 1 includes a resin containing a high molecular weight component and a thermosetting component mainly composed of an epoxy resin and a filler having a thickness of 10 to 250 μm. Adhesive sheets have been proposed. Patent Document 2 proposes an adhesive composition containing a mixture containing an epoxy resin and a phenol resin and an acrylic copolymer.

  The connection reliability of a semiconductor device depends greatly on whether or not a semiconductor element can be mounted without generating a gap on the bonding surface. For this reason, a highly fluid film adhesive is used so that the semiconductor element can be crimped without generating a void, or a film having a low elastic modulus so that the generated void can be eliminated in the sealing process of the semiconductor element. Ingenuity has been made such as using adhesives. For example, Patent Document 3 proposes an adhesive sheet having low viscosity and low tack strength.

  The adhesive films of Patent Documents 1 and 3 contain a large amount of epoxy resin or the like for the purpose of increasing the fluidity in order to embed the wire during crimping. For this reason, thermosetting progresses due to heat generated during the manufacturing process of the semiconductor device, and the adhesive film becomes highly elastic. Therefore, the adhesive film does not deform even under high temperature and high pressure conditions at the time of sealing, and is formed at the time of pressure bonding. The voids may not eventually disappear. On the other hand, since the adhesive film of Patent Document 2 has a low elastic modulus and can eliminate voids in the sealing process, it has a high viscosity, so that the wire cannot be embedded at the time of pressure bonding.

International Publication No. 2005/103180 JP 2002-220576 A JP 2009-120830 A

  In recent years, high-speed operation of wire-embedded semiconductor devices has been regarded as important. Conventionally, a controller chip for controlling the operation of the semiconductor device has been arranged at the top of the stacked semiconductor elements. However, in order to realize high-speed operation, the semiconductor device packaging technology has a controller chip arranged at the bottom. Has been developed. As one form of such a package, among the semiconductor elements stacked in multiple stages, the film adhesive used when crimping the second-stage semiconductor element is thickened, and the controller chip is placed inside the film adhesive. Embed packages are attracting attention. The film adhesive used for such applications requires a high fluidity that can embed a controller chip, a wire connected to the controller chip, and a step due to unevenness on the substrate surface. These problems can be solved by using a highly fluid film such as the adhesive sheet 1.

  However, the adhesive sheets described in Patent Documents 1 and 3 contain a large amount of a thermosetting component such as an epoxy resin in order to develop high fluidity before curing. For this reason, after hardening, since the elasticity modulus is high and the glass transition temperature Tg becomes high, the obtained semiconductor device tends to warp. In particular, in recent years, a large capacity of a semiconductor device in which semiconductor elements are stacked in multiple stages has been actively promoted, and the thinning of semiconductor elements has been progressing rapidly. In the case of using such a thinned semiconductor element, the warp of the semiconductor device becomes more remarkable, and sufficient adhesiveness cannot be obtained when the semiconductor elements are stacked in multiple stages. Multi-layer stacking becomes difficult because connection reliability cannot be obtained.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a film-like adhesive and a dicing die bonding integrated adhesive sheet that exhibit good connection reliability even when a thinned semiconductor element is used. And

  In order to solve the above-mentioned problems, the present inventors have conducted extensive research on the selection of a resin for a film adhesive used in a semiconductor device and the adjustment of physical properties. The inventors have found that the elastic modulus after curing of the film adhesive and the glass transition temperature Tg correlate with the warp of the semiconductor device after manufacture.

  That is, in order to solve the above-described problem, in the semiconductor device according to the present invention, the first semiconductor element is wire-bonded to the substrate via the first wire, and the first semiconductor element is connected to the first semiconductor element. Wire embedding in which the first semiconductor element and the first semiconductor element are embedded in the film adhesive by pressing the second semiconductor element larger than the area of the semiconductor element via the film adhesive The film type adhesive has a modulus of elasticity at 50 ° C. after curing of 1000 MPa or less, a modulus of elasticity at 150 ° C. to 260 ° C. after curing of 20 MPa or less, and a glass transition temperature Tg of 150 MPa. It is characterized by being below ℃.

  In the semiconductor device, the film adhesive used for pressure-bonding the second semiconductor element onto the first semiconductor element has low elasticity after curing and exhibits a low glass transition temperature Tg. For this reason, even when a thin 2nd semiconductor element is used, the curvature of the semiconductor device after a film adhesive hardens | cures can be suppressed. Thereby, the stress of a semiconductor device is relieved and the semiconductor device which shows favorable connection reliability can be obtained.

  In the semiconductor device according to the present invention, the film adhesive is (a1) at least one of an epoxy resin whose softening point is 60 ° C. or lower or liquid at room temperature and a phenol resin whose softening point is 60 ° C. or lower or liquid at normal temperature. And (a2) at least one of an epoxy resin having a softening point higher than 60 ° C. and an epoxy equivalent of 190 or higher and a phenol resin having a softening point higher than 60 ° C. and a hydroxyl equivalent equivalent of 190 or higher. Parts by weight, (b1) a first high molecular weight component having a crosslinkable functional group in a monomer ratio of 5 to 15%, a weight average molecular weight of 100,000 to 400,000, and a glass transition temperature Tg of −50 to 50 ° C. And (b2) a second high molecular weight component having a crosslinkable functional group in a monomer ratio of 1 to 7%, a weight average molecular weight of 500,000 to 800,000 and a glass transition temperature Tg of −50 to 50 ° C. (B) 20 to 160 parts by mass of a high molecular weight component, (c1) a first filler having an average particle diameter of 0.2 μm or more, and (c2) a second filler having an average particle diameter of less than 0.2 μm. (C) Inorganic filler is included in an amount of 10 to 90 parts by mass, and (d) a curing accelerator is included in an amount of 0 to 0.20 parts by mass, and (a1) component content is (a) thermosetting. The content of the component (a2) is 25% by mass or more based on 100 parts by mass of the (a) thermosetting component, and the content of the component (b1). Is preferably 50% by mass or more based on 100 parts by mass of the (b) high molecular weight component, and the content of the component (c1) is preferably 30% by mass or more based on 100 parts by mass of the inorganic filler (c).

  The film adhesive is a combination of thermosetting resins having different curing speeds, such as the components (a1) and (a2), and a crosslinkable functional group such as the components (b1) and (b2). By mixing high molecular weight components adjusted in group ratio, weight average molecular weight and glass transition temperature Tg, and further combining components (c1), (c2) and (d), these components are combined with each other, The elasticity, glass transition temperature Tg and tack strength after curing are lowered. Therefore, even when a thin semiconductor element is used, warping of the semiconductor element after curing can be suppressed.

  The film adhesive preferably has a temperature at which the shear viscosity before curing is 5000 Pa · s or less, at a temperature of 60 to 175 ° C. In this case, since excellent embedding property is exhibited, the second semiconductor element can be pressure-bonded without generating a gap on the bonding surface. Thereby, the connection reliability of the obtained semiconductor device can be improved.

  The film adhesive preferably has an adhesive strength after curing with a substrate coated with AUS308 of 1.0 MPa or more. In this case, the connection reliability of the obtained semiconductor device becomes better.

  In the semiconductor device according to the present invention, it is preferable that a third semiconductor element is further stacked on the second semiconductor element. In this case, the capacity of the obtained semiconductor device can be increased.

  In the semiconductor device according to the present invention, the substrate and the second semiconductor element are further electrically connected via the second wire, and the second semiconductor element is sealed with a resin. preferable. In this case, the reliability of the obtained semiconductor device is further increased.

  In addition, a method for manufacturing a semiconductor device according to the present invention includes a first die bonding step of electrically connecting a first semiconductor element on a substrate via a first wire, and a single side of the second semiconductor element. A laminating step of applying a film-like adhesive in accordance with the shape of the second semiconductor element, and a second semiconductor element to which the film-like adhesive is attached so that the film-like adhesive covers the first semiconductor element. The first wire and the first semiconductor element are bonded to each other by pressing the film adhesive under conditions of 80 to 180 ° C. and 0.01 to 0.50 MPa for 0.5 to 3.0 seconds. And a die-bonding step embedded in the adhesive. In this case, the semiconductor device according to the present invention can be stably manufactured.

  Moreover, the method for manufacturing a semiconductor device according to the present invention further includes a step of pressing and heating for 5 minutes or more under the conditions of 60 to 175 ° C. and 0.3 to 0.7 MPa as a step immediately after the die bonding step. Is preferred. In this case, a slight void remaining in the die-bonding process can be eliminated, so that the semiconductor device can be manufactured more easily while stabilizing the yield.

  The film adhesive preferably has a temperature at which the shear viscosity before curing is 5000 Pa · s or less, at a temperature of 60 to 175 ° C. In this case, since excellent embedding property is exhibited, the second semiconductor element can be pressure-bonded without generating a gap on the bonding surface. Thereby, the connection reliability of the obtained semiconductor device can be improved.

  The film adhesive preferably has an adhesive strength after curing with a substrate coated with AUS308 of 1.0 MPa or more. In this case, the connection reliability of the obtained semiconductor device becomes better.

  In the semiconductor device according to the present invention, it is preferable that a third semiconductor element is further stacked on the second semiconductor element. In this case, the capacity of the obtained semiconductor device can be increased.

  The semiconductor device according to the present invention includes a second wire bonding step of electrically connecting the substrate and the second semiconductor element through the second wire, and sealing the second semiconductor element with a resin. It is preferable to further include a process. In this case, the reliability of the obtained semiconductor device is further increased.

  According to the present invention, it is possible to provide a film adhesive and a dicing die bonding integrated adhesive sheet that exhibit good connection reliability even when a thinned semiconductor element is used.

It is a figure which shows the film adhesive which concerns on embodiment of this invention. It is a figure which shows the adhesive sheet which concerns on embodiment of this invention. It is a figure which shows the adhesive sheet which concerns on other embodiment of this invention. It is a figure which shows the adhesive sheet which concerns on other embodiment of this invention. It is a figure which shows the adhesive sheet which concerns on other embodiment of this invention. It is a figure showing a semiconductor device concerning an embodiment of the present invention. It is a figure which shows the manufacturing method of the semiconductor device which concerns on embodiment of this invention. FIG. 8 is a diagram showing a step subsequent to FIG. 7. FIG. 9 is a diagram showing a step subsequent to that in FIG. 8. FIG. 10 is a diagram showing a step subsequent to FIG. 9. FIG. 11 is a diagram showing a step subsequent to FIG. 10.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. In this specification, “(meth) acryl” means “acryl” and “methacryl” corresponding to it.

(Film adhesive)
FIG. 1 is a cross-sectional view schematically showing a film adhesive 10 according to the present embodiment. The film-like adhesive 10 is thermosetting and can be produced by forming a film-like adhesive composition that can be in a completely cured (C-stage) state after the curing process through a semi-cured (B-stage) state. .

  The film adhesive 10 has an elastic modulus at 50 ° C. after curing of 1000 MPa or less, an elastic modulus of 150 ° C. to 260 ° C. after curing of 20 MPa or less, and a glass transition temperature Tg of 150 ° C. or less.

  The film adhesive 10 preferably has a temperature at which the shear viscosity before curing is 5000 Pa · s or less, at a temperature of 60 to 175 ° C. In this case, since excellent embedding property is exhibited, the second semiconductor element can be pressure-bonded without generating a gap on the bonding surface. Thereby, the connection reliability of the obtained semiconductor device can be improved.

  The shear viscosity is measured using ARES (manufactured by Rheometric Scientific) and increasing the temperature at a heating rate of 5 ° C./min while applying 5% strain to the film adhesive 10. Means the measured value. On the other hand, the tensile elastic modulus means a measured value when measured using a dynamic viscoelasticity measuring device (UBM) while increasing the temperature at a temperature increase rate of 3 ° C./min. The adhesive breaking elongation and breaking strength were tested when a 10 mm wide, 60 μm thick uncured film adhesive was set in a tensile tester with a chuck distance of 20 mm and pulled at a speed of 50 mm / min. It means the elongation and tensile strength until the piece breaks.

  Moreover, it is preferable that the adhesive force after hardening to the board | substrate which apply | coated AUS308 with the film adhesive 10 is 1.0 Mpa or more. In this case, the connection reliability of the obtained semiconductor device becomes better.

  The film adhesive 10 includes (a1) at least one of an epoxy resin having a softening point of 60 ° C. or lower or liquid at room temperature and a phenol resin having a softening point of 60 ° C. or lower or liquid at normal temperature (hereinafter simply referred to as “(a1) And (a2) at least one of an epoxy resin having a softening point higher than 60 ° C. and an epoxy equivalent of 190 or higher, and a phenol resin having a softening point higher than 60 ° C. and a hydroxyl equivalent equivalent of 190 or higher (hereinafter referred to as “component”). , Simply described as “component (a2)”), and 100 parts by mass of a thermosetting resin containing (b1) a crosslinkable functional group in a monomer ratio of 5 to 15%, and a weight average molecular weight of 100,000 to A first high molecular weight component having a glass transition temperature Tg of −50 to 50 ° C. (hereinafter simply referred to as “component (b1)”) and (b2) a crosslinkable functional group in a monomer ratio. 1-7 And a second high molecular weight component having a weight average molecular weight of 500,000 to 800,000 and a glass transition temperature Tg of −50 to 50 ° C. (hereinafter simply referred to as “component (b2)”). (B) a high molecular weight component (20 to 160 parts by mass), (c1) a first filler having an average particle size of 0.2 μm or more (hereinafter simply referred to as “(c1) component”), and (c2) A second filler having an average particle size of less than 0.2 μm (hereinafter simply referred to as “component (c2)”), (c) 10 to 90 parts by mass of an inorganic filler, and (d) curing. It is preferable to contain 0 to 0.20 parts by mass of an accelerator.

  The film adhesive 10 is a combination of thermosetting resins having different curing speeds such as the component (a1) and the component (a2), and a crosslinkable functional group such as the component (b1) and the component (b2). By mixing high molecular weight components adjusted in the ratio, weight average molecular weight and glass transition temperature Tg, and further combining the components (c1), (c2) and (d), elasticity after curing, glass transition temperature Tg and tack The strength is lowered. Therefore, even when a thin semiconductor element is used, warping of the semiconductor element after curing can be suppressed. Moreover, the film adhesive 10 can acquire favorable sclerosis | hardenability by including the (d) effect promoter.

  Here, in order to set the elastic modulus at 50 ° C. after curing of the film adhesive 10 to 1000 MPa or less, the elastic modulus from 150 ° C. to 260 ° C. to 20 MPa or less, and the glass transition temperature Tg to 150 ° C. or less, for example, It can be adjusted by increasing the amount of (a2) component, (c) decreasing the content of inorganic filler, and (b) increasing the content of high molecular weight component.

  Moreover, in order to make the temperature at which the shear viscosity of the film adhesive 10 becomes 5000 Pa · s or less becomes any temperature of 60 to 175 ° C., for example, (b) reduce the content of the high molecular weight component, It can be adjusted by increasing the content of the component (a1), increasing the content of the component (b1) to reduce the content of the component (b2), and reducing the content of the inorganic filler (c).

  Moreover, in order to make the adhesive force after hardening with the board | substrate which apply | coated AUS308 set to 1.0 Mpa or more, it adjusts by reducing the amount of (a2) component, for example, and increasing the content of (c) inorganic filler. be able to.

  The film adhesive 10 preferably contains an additive such as (e) a coupling agent from the viewpoint of obtaining sufficient adhesiveness.

  (A) As a thermosetting component, a thermosetting resin is preferable and an epoxy resin, a phenol resin, etc. which have the heat resistance and moisture resistance required when mounting a semiconductor element are preferable.

  In order to obtain good embedding property when a semiconductor element is pressure-bonded and to eliminate voids in a pressure oven, the temperature at which the shear viscosity becomes 5000 Pa · s or less is set to any temperature of 60 to 175 ° C. It is preferable. In order to set the temperature at which the shear viscosity becomes 5000 Pa · s or less by adjusting the thermosetting resin to any one of 60 to 175 ° C., the content of the component (a1) is (a) thermosetting. It is necessary to contain 30% by mass or more based on 100 parts by mass of the component.

  Examples of the epoxy resin as the component (a1) include an epoxy resin represented by the general formula (1).

（１）
（式（１）中、ｎは０〜５を示す。）

(1)
(In formula (1), n represents 0 to 5)

  The epoxy resin of the component (a1) other than the general formula (1) is not particularly limited as long as the softening point is an epoxy resin that is liquid at a temperature of 60 ° C. or lower or normal temperature and has an adhesive action when cured. Bifunctional epoxy resins obtained by modifying bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol E type epoxy resins, or the like may be used. Examples of such an epoxy resin include VG3101L (epoxy equivalent 210).

  In order to suppress warpage of the manufactured semiconductor device, it is necessary that the elastic modulus at 50 ° C. after curing is 1000 MPa or less, the elastic modulus at 150 ° C. to 260 ° C. is 20 MPa or less, and the glass transition temperature Tg is 150 ° C. or less. However, in order to adjust the (a) thermosetting resin to satisfy the above-described requirements for the elastic modulus and the glass transition temperature Tg, it is necessary to contain the component (a2) at 25% by mass or more. Examples of such epoxy resins include SR35K (epoxy equivalent 938) manufactured by Printec Co., Ltd., and examples of phenol resins include the HE series (eg, HE200C-10) manufactured by Air Water Co., Ltd. Can be mentioned.

  You may use together epoxy resin other than (a1) component and (a2) component as (a) thermosetting resin. For example, a novolac epoxy resin such as a phenol novolac epoxy resin or a cresol novolac epoxy resin can be used. Moreover, what is generally known, such as a polyfunctional epoxy resin, a glycidyl amine type epoxy resin, a heterocyclic containing epoxy resin, or an alicyclic epoxy resin, can also be used as an epoxy resin.

  Moreover, you may use together phenol resin other than (a1) component and (a2) component as (a) thermosetting resin. Examples include Phenolite KA, TD series manufactured by DIC Corporation, and Millex XLC-series and XL series (for example, Millex XLC-LL) manufactured by Mitsui Chemicals, Inc., but from the viewpoint of heat resistance, 85 ° C. , The water absorption after 2 hours in a constant temperature and humidity chamber of 85% RH is 2% by mass or less, and the heating mass decrease rate at 350 ° C. measured with a thermogravimetric analyzer (TGA) (temperature increase rate: 5 ° C. / Min, atmosphere: nitrogen) is preferably less than 5% by mass.

  (A) When both an epoxy resin and a phenol resin are included as a thermosetting component, the compounding quantity of an epoxy resin and a phenol resin is 0.70 / 0.30-0.30 by the equivalent ratio of an epoxy equivalent and a hydroxyl equivalent, respectively. /0.70, preferably 0.65 / 0.35 to 0.35 / 0.65, and more preferably 0.60 / 0.40 to 0.40 / 0.60. Is more preferably 0.60 / 0.40 to 0.50 / 0.50. If the blending ratio exceeds the above range, the produced film adhesive may be inferior in curability. Alternatively, the viscosity of the uncured film adhesive may be increased and the fluidity may be inferior.

  (B) As the high molecular weight component, a combination of a high molecular weight component having a high crosslinkable functional group ratio and a low molecular weight and a high molecular weight component having a low crosslinkable functional group ratio and a high molecular weight is preferable. It is preferable that more than the amount is contained. That is, (b1) a first high molecular weight component having a crosslinkable functional group in a monomer ratio of 5 to 15%, a weight average molecular weight of 100,000 to 400,000, and a glass transition temperature Tg of −50 to 50 ° C. (B2) from a second high molecular weight component having a crosslinkable functional group in a monomer ratio of 1 to 7%, a weight average molecular weight of 500,000 to 800,000 and a glass transition temperature Tg of -50 to 50 ° C. Therefore, the content of the component (b1) is preferably 50% by mass or more based on 100 parts by mass of the (b) high molecular weight component.

  Acrylic resin is preferable for both the component (b1) and the component (b2), and the glass transition temperature Tg is −50 ° C. to 50 ° C. and has an epoxy group or glycidyl group such as glycidyl acrylate or glycidyl methacrylate as a crosslinkable functional group. An acrylic resin such as an epoxy group-containing (meth) acrylic copolymer obtained by polymerizing a functional monomer is more preferable.

  As such a resin, an epoxy group-containing (meth) acrylic acid ester copolymer, an epoxy group-containing acrylic rubber or the like can be used, and an epoxy group-containing acrylic rubber is more preferable. The epoxy group-containing acrylic rubber is a rubber having an epoxy group mainly composed of an acrylate ester and mainly composed of a copolymer such as butyl acrylate and acrylonitrile, a copolymer such as ethyl acrylate and acrylonitrile, or the like. .

  In addition, as a crosslinkable functional group of (b) high molecular weight component, not only an epoxy group but crosslinkable functional groups, such as alcoholic or phenolic hydroxyl group, a carboxyl group, are mentioned.

The weight average molecular weight is a polystyrene conversion value using a standard polystyrene calibration curve by gel permeation chromatography (GPC).
The glass transition temperature is measured using a DSC (thermal differential scanning calorimeter) (for example, “Thermo Plus 2” manufactured by Rigaku Corporation).

  The content of the component (b1) is preferably 50% or more, more preferably 55% to 90%, based on 100 parts by mass of the (b) high molecular weight component. When the content of the component (b1) is more than 50%, the viscosity can be reduced and the embedding property becomes good. On the other hand, when the content of the component (b1) is 90% or less, the adhesive strength after curing becomes better.

  Moreover, the softness | flexibility of the film adhesive 10 becomes favorable that the glass transition temperature Tg of (b) high molecular weight component is 50 degrees C or less. On the other hand, when the glass transition temperature Tg is −50 ° C. or higher, the flexibility of the film adhesive does not become too high, so that the film adhesive 10 is easily cut when dicing the semiconductor wafer. For this reason, it can suppress that dicing property deteriorates by generation | occurrence | production of a burr | flash.

  The weight average molecular weight of the component (b1) is preferably 100,000 or more and 400,000 or less. When the weight average molecular weight of the component (b1) is 100,000 or more, the film-forming property is improved and the adhesive strength and heat resistance of the film adhesive 10 can be improved. When the weight average molecular weight of the component (b1) is 400,000 or less, the shear viscosity can be reduced, so that the embedding property of the film adhesive 10 is improved. In addition, the adhesive strength can measure the below-mentioned die shear strength.

  The weight average molecular weight of the component (b2) is preferably 500,000 or more and 800,000 or less. When the weight average molecular weight of the component (b2) is 500,000 or more, the effect of improving the film formability is further improved by the combined use with the component (b1). When the weight average molecular weight of the component (b2) is 800,000 or less, the shear viscosity of the uncured film adhesive can be reduced, so that the embedding property is improved. In addition, the machinability of the uncured film adhesive may be improved, and the quality of dicing may be improved.

  (B) The high molecular weight component is preferably a high molecular weight component having a Tg of -20 ° C to 40 ° C as a whole, and preferably includes a high molecular weight component having a Tg of -10 ° C to 30 ° C. In this case, the film adhesive can be easily cut at the time of dicing, resin waste is hardly generated, the adhesive strength and heat resistance are high, and the high fluidity of the uncured film adhesive can be expressed.

  (B) It is preferable to contain 20-160 mass parts of high molecular weight components with respect to 100 mass parts of (a) thermosetting components. (B) When the content of the high molecular weight component is 20 parts by mass or more, the flexibility of the film can be prevented from being lowered, and after heating, the elasticity is lowered and the warping of the package is suppressed. On the other hand, when the content of (b) the high molecular weight component is 160 parts by mass or less, the fluidity of the uncured film is increased and the embedding property is improved.

  Furthermore, in order to develop a high adhesive force, the monomer ratio of the functional monomer such as glycidyl acrylate or glycidyl methacrylate as the component (b1) is preferably 5 to 15%, and the tensile elastic modulus after heating at 150 ° C./1 hour is kept low. Therefore, 5 to 10% is more preferable. Here, the “monomer ratio” means the ratio of the weight of the functional monomer used in the total weight of all monomers used.

  The high molecular weight component (b) used in the present invention can also be obtained as a commercial product. For example, trade name “acrylic rubber HTR-860P-30B-CHN” manufactured by Teikoku Chemical Industry Co., Ltd. can be used. This compound has a glycidyl moiety as a crosslinkable functional group and is a compound based on an acrylic rubber made of an acrylic acid derivative and has a weight average molecular weight of 100,000 to 300,000 and a glass transition temperature Tg (−7 ° C.). It is.

  (C) As an inorganic filler, the improvement of the dicing property of the film adhesive in the B stage state, the improvement of the handling property of the film adhesive, the improvement of the thermal conductivity, the adjustment of the melt viscosity, the provision of thixotropic property, the adhesion From the viewpoint of improving the force, it is preferable to add a silica filler.

  In the adhesive composition of this embodiment, from the viewpoint of controlling the fluidity and breakability of the uncured film adhesive and the tensile modulus and adhesive force of the film adhesive after curing, (a) a thermosetting component It is preferable to blend 10 to 90 parts by mass of (c) inorganic filler with respect to 100 parts by mass. When the inorganic filler (c) below the lower limit is blended, the dicing property of the uncured film adhesive may be deteriorated and the adhesive strength after curing may be reduced. On the other hand, when the inorganic filler (c) exceeding the above upper limit is blended, the fluidity of the uncured film-like adhesive tends to decrease, and the elastic modulus after curing tends to increase.

  (C) The inorganic filler is preferably mixed with two or more fillers having different average particle diameters for the purpose of improving the dicing properties of the uncured film adhesive and sufficiently expressing the adhesive strength after curing. That is, the average particle size for the purpose of sufficiently expressing the first filler having an average particle size of 0.2 μm or more for the purpose of improving the breakability of the uncured film adhesive and the cured adhesive force. It is preferable that particles containing a second filler of less than 0.2 μm and having a particle size of 0.2 μm or more occupy 30% by mass or more based on 100 parts by mass of (c) inorganic filler. When the content of the first filler is less than 30% by volume, the breakability of the film deteriorates and the fluidity of the uncured film adhesive tends to deteriorate. Here, the “average particle size” is a value obtained when acetone is used as a solvent in a laser diffraction particle size distribution analyzer. It is more preferable for the fillers of each type to have a large difference in average particle size to such an extent that the average particle size can be determined by a particle size distribution measuring device.

(D) Curing accelerator For the purpose of obtaining good curability, it is preferable to add (d) a curing accelerator. From the viewpoint of reactivity, an imidazole compound is preferable. A curing accelerator that is too reactive has a tendency not only to increase the shear viscosity by heating during the production process of the film-like adhesive, but also to cause significant deterioration over time. On the other hand, a curing accelerator having a reactivity that is too low makes it difficult for the film-like adhesive to be completely cured by the thermal history in the manufacturing process of the semiconductor device, and it is mounted in the product uncured, There is a possibility that sufficient adhesiveness cannot be obtained and the connection reliability of the semiconductor device is deteriorated.

  If the amount of curing accelerator added is too small, it will be difficult to completely cure the film adhesive due to the heat history in the semiconductor device manufacturing process, and it will be mounted in the product uncured. Then, there is a risk of inducing subsequent device failures. On the other hand, when the addition amount of the curing accelerator is too large, not only the shear viscosity is increased by heating during the production process of the film adhesive, but also there is a tendency that the deterioration with time is remarkably caused. From such a viewpoint, the curing accelerator is preferably contained in an amount of 0 to 0.20 parts by mass with respect to 100 parts by mass of the thermosetting resin.

(E) Other ingredients:
It is preferable that the adhesive composition of this embodiment contains (e) a coupling agent from a viewpoint of an adhesive improvement other than said (a)-(d) component. Examples of the coupling agent include γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, and the like.

(Film adhesive and adhesive sheet)
As the film-like adhesive 10, an adhesive composition obtained by applying the above-described adhesive composition varnish on a base film and drying it can be used as an adhesive sheet. Specifically, first, varnish is prepared by mixing and kneading components (a) to (d) and, if necessary, other additive components such as the above (e) coupling agent in an organic solvent.

  The above mixing and kneading can be performed by using a normal stirrer, a raking machine, a three-roller, a ball mill, or other disperser and appropriately combining them. The above-mentioned heat drying is not particularly limited as long as the solvent used is sufficiently volatilized, but it can be usually performed by heating at 60 ° C. to 200 ° C. for 0.1 to 90 minutes.

  The organic solvent for producing the varnish is not particularly limited as long as it can uniformly dissolve, knead or disperse the above components, and a conventionally known one can be used. Examples of such solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, dimethylformamide, dimethylacetamide, N methylpyrrolidone, toluene, xylene, and the like. It is preferable to use methyl ethyl ketone, cyclohexanone, etc. in terms of fast drying speed and low price.

  There is no restriction | limiting in particular as said base film, For example, a polyester film, a polypropylene film (OPP film etc.), a polyethylene terephthalate film, a polyimide film, a polyetherimide film, a polyether naphthalate film, a methylpentene film etc. are mentioned. .

  Next, a layer of the varnish is formed by applying the obtained varnish on the base film. Next, after removing a solvent from a varnish layer by heat drying, the film adhesive 10 is obtained by removing a base film.

  As one of the methods for producing the thick film adhesive 10, there is a method in which the film adhesive 10 obtained in advance and the film adhesive 10 formed on the base film are bonded to each other. .

  The thickness of the film adhesive 10 is preferably 20 to 200 μm so that the first semiconductor element and the wire for connecting the semiconductor element, and irregularities such as the wiring circuit of the substrate can be sufficiently filled. If the film thickness is less than 20 μm, the adhesive force tends to be poor. If the film thickness is more than 200 μm, it is not economical and it is difficult to meet the demand for downsizing of the semiconductor device. In addition, the film thickness of the film adhesive 10 is more preferably 30 to 200 μm, and even more preferably 40 to 150 μm, in terms of high adhesiveness and thinning of the semiconductor device.

  As shown in FIG. 2, the film adhesive 10 can be used as an adhesive sheet 100 in which the film adhesive 10 is laminated on the base film 20 without removing the base film coated with the varnish.

  Moreover, as shown in FIG. 3, the film adhesive 10 can also be used as the adhesive sheet 110 which provided the cover film 30 on the opposite side to the surface in which the base film 20 was provided. Examples of the cover film 30 include a PET film, a PE film, and an OPP film.

  The film adhesive can also be used as a dicing / die bonding integrated adhesive sheet in which the film adhesive 10 is laminated on a dicing tape. In this case, it is possible to increase the efficiency of the operation in that the laminating process on the semiconductor wafer is performed only once.

  Examples of the dicing tape include plastic films such as a polytetrafluoroethylene film, a polyethylene terephthalate film, a polyethylene film, a polypropylene film, a polymethylpentene film, and a polyimide film. In addition, the dicing tape may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, and etching treatment as necessary.

  Further, the dicing tape preferably has adhesiveness, and the above-mentioned plastic film provided with adhesiveness may be used, or an adhesive layer may be provided on one side of the above-mentioned plastic film.

  Examples of such a dicing / die bonding integrated adhesive sheet include an adhesive sheet 120 shown in FIG. 4 and an adhesive sheet 130 shown in FIG. 5. As shown in FIG. 4, the adhesive sheet 120 uses a dicing tape 60 in which an adhesive layer 50 is provided on a base film 40 that can ensure elongation when a tensile tension is applied, as a supporting base material. The adhesive layer 50 has a structure in which the film adhesive 10 is provided. As shown in FIG. 5, in the adhesive sheet 130, the base film 20 is provided on the surface of the film adhesive 10 in the adhesive sheet 120.

  Examples of the base film 40 include the above-described plastic film described for the dicing tape. Moreover, the adhesive layer 50 includes, for example, a resin composition containing a liquid component and a high molecular weight component and having an appropriate tack strength. The dicing tape can be formed by applying the adhesive layer 50 on the base film 40 and drying, or by bonding the adhesive layer applied to the base film such as a PET film and drying to the base film 40. is there. The tack strength is set to a desired value, for example, by adjusting the ratio of the liquid component and the Tg of the high molecular weight component.

  When a dicing / die bonding integrated adhesive sheet such as the adhesive sheet 120 and the adhesive sheet 130 is used for manufacturing a semiconductor device, the semiconductor element has an adhesive force that does not scatter during dicing, and can be easily peeled off from the dicing tape during subsequent pickup. is necessary.

  Such characteristics can be obtained by adjusting the tack strength of the pressure-sensitive adhesive layer as described above, and changing the tack strength due to photoreaction, etc., but if the tackiness of the film adhesive is too high, picking up becomes difficult. Sometimes. Therefore, it is preferable to appropriately adjust the tack strength of the film adhesive 10. As the method, for example, when the flow of the film-like adhesive 10 at room temperature (25 ° C.) is increased, the adhesive strength and tack strength tend to increase, and when the flow is decreased, the adhesive strength and tack strength tend to decrease. You can take advantage of that.

  For example, when increasing the flow, a method such as increasing the content of a compound that functions as a plasticizer can be used. In the case of reducing the flow, for example, a method of reducing the content of a compound that functions as a plasticizer can be mentioned. Examples of the plasticizer include monofunctional acrylic monomers, monofunctional epoxy resins, liquid epoxy resins, and acrylic resins.

  As a method of laminating the film-like adhesive 10 on the dicing tape 60, a previously prepared book may be used in addition to a method in which the varnish of the adhesive composition described above is applied to the entire surface and dried, or partially applied by printing. The method of laminating the film-like adhesive 10 of the invention on the dicing tape 60 by press or hot roll laminating is mentioned. In the present embodiment, a hot roll laminating method is preferable because it can be continuously manufactured and is efficient.

  The film thickness of the dicing tape 60 is not particularly limited, and can be appropriately determined based on the knowledge of those skilled in the art depending on the film thickness of the film adhesive 10 and the application of the dicing / die bonding integrated adhesive sheet. When the thickness of the dicing tape 60 is less than 60 μm, the handleability is poor, and the dicing tape 60 tends to be broken by the expansion in the process of separating the semiconductor elements separated by the dicing from the dicing tape 60. On the other hand, from the viewpoints of economy and good handleability, the thickness of the dicing tape 60 is preferably 180 μm or less, and as described above, the thickness of the dicing tape 60 is preferably 60 to 180 μm.

(Semiconductor device)
FIG. 6 is a cross-sectional view showing the semiconductor device according to the present embodiment. As shown in FIG. 6, the semiconductor device 200 is a semiconductor device in which a second semiconductor element Waa is stacked on a first semiconductor element Wa. Specifically, the first semiconductor element Wa in the first stage is connected to the substrate 14 via the first wire 88 by wire bonding, and the first semiconductor element Wa is formed on the first semiconductor element Wa. The second semiconductor element Waa in the second stage larger than the area is pressure-bonded via the film adhesive 10 so that the first wire 88 and the first semiconductor element Wa are embedded in the film adhesive 10. This is a wire embedded semiconductor device. In the semiconductor device 200, the substrate 14 and the second semiconductor element Waa are further electrically connected via the second wire 98, and the second semiconductor element Waa is sealed with the sealing material 42. ing.

  The thickness of the first semiconductor element Wa is 10 to 170 μm, and the thickness of the second semiconductor element Waa is 20 to 400 μm. The thickness of the film adhesive 10 is 20-200 micrometers, Preferably it is 30-200 micrometers, More preferably, it is 40-150 micrometers. The first semiconductor element Wa embedded in the film adhesive 10 is a controller chip for driving the semiconductor device 200.

  The substrate 14 is composed of an organic substrate 90 on which two circuit patterns 84 and 94 are formed on the surface. The first semiconductor element Wa is crimped onto the circuit pattern 94 via an adhesive 41, and the second semiconductor element Waa is a circuit pattern 94 in which the first semiconductor element Wa is not crimped. The semiconductor element Wa and a part of the circuit pattern 84 are pressure-bonded to the substrate 14 via the film adhesive 10. The film adhesive 10 is embedded in the uneven steps due to the circuit patterns 84 and 94 on the substrate 14. The second semiconductor element Waa, the circuit pattern 84, and the second wire 98 are sealed with a resin sealing material 42.

(Method for manufacturing semiconductor device)
The semiconductor device 200 according to the present embodiment is manufactured by the following procedure. First, as shown in FIG. 7, the first semiconductor element Wa with the adhesive 41 is pressure-bonded onto the circuit pattern 94 on the substrate 14, and the circuit pattern 84 on the substrate 14 and the first pattern are connected to each other via the first wire 88. The first semiconductor element Wa is electrically bonded and connected (first die bonding step).

  Next, the adhesive sheet 100 is laminated on one side of a 50 μm-thick semiconductor wafer (size: 8 inches), and the base film 20 is peeled off, so that the film-like adhesive 10 (thickness 135 μm) is pasted on one side of the semiconductor wafer. wear. Then, after the dicing tape 60 is bonded to the film adhesive 10, dicing into 7.5 mm square is performed to obtain the second semiconductor element Waa to which the film adhesive 10 is applied as shown in FIG. 8. (Lamination process).

  The laminating step is preferably performed at 50 to 100 ° C, more preferably 60 to 80 ° C. When the temperature in the laminating step is 50 ° C. or higher, good adhesion to the semiconductor wafer can be obtained. When the temperature of the laminating process is 100 ° C. or lower, the film-like adhesive 10 can be prevented from flowing excessively during the laminating process, so that it is possible to prevent a change in thickness and the like.

  Examples of the dicing method include blade dicing using a rotary blade, a method of cutting a film adhesive or both a wafer and a film adhesive with a laser, and a general method such as stretching under normal temperature or cooling conditions.

  Then, the second semiconductor element Waa to which the film adhesive 10 is attached is pressure-bonded to the substrate 14 to which the first semiconductor element Wa is bonded and connected via the first wire 88. Specifically, as shown in FIG. 9, the second semiconductor element Waa attached with the film adhesive 10 is placed so that the film adhesive 10 covers the first semiconductor element Wa, As shown in FIG. 10, the second semiconductor element Waa is fixed to the substrate 14 by pressing the second semiconductor element Waa to the substrate 14 (die bonding step). In the die bonding step, the film adhesive 10 is preferably pressure bonded for 0.5 to 3.0 seconds under conditions of 80 to 180 ° C. and 0.01 to 0.50 MPa. After the die bonding step, the film adhesive 10 is pressed and heated for 5 minutes or more under the conditions of 60 to 175 ° C. and 0.3 to 0.7 MPa.

  Next, as shown in FIG. 11, after electrically connecting the substrate 14 and the second semiconductor element Waa via the second wire 98 (second wire bonding step), the circuit pattern 84, the second semiconductor element Waa is connected. The wire 98 and the second semiconductor element Waa are sealed with the sealing material 42. The semiconductor device 200 can be manufactured through such steps.

  As described above, in this semiconductor device 200, the first semiconductor element Wa is connected to the substrate 14 via the first wire 88 by wire bonding, and the first semiconductor element Wa is connected to the first semiconductor element Wa. The second semiconductor element Waa larger than the area of the semiconductor element Wa is pressure-bonded via the film adhesive 10, whereby the first wire 88 and the first semiconductor element Wa are embedded in the film adhesive 10. The film-like adhesive 10 has a modulus of elasticity at 50 ° C. after curing of 1000 MPa or less, and a modulus of elasticity at 150 ° C. to 260 ° C. after curing of 20 MPa or less. The glass transition temperature Tg is 150 ° C. or lower.

  In the semiconductor device 200, the film adhesive 10 used for pressure-bonding the second semiconductor element Waa onto the first semiconductor element Wa has low elasticity after curing and exhibits a low glass transition temperature Tg. . For this reason, even when thin 2nd semiconductor element Waa is used, the curvature of the semiconductor device 200 after the film adhesive 10 hardens | cures can be suppressed. Thereby, the stress of the semiconductor device 200 is relieved and a semiconductor device exhibiting good connection reliability can be obtained.

  In the semiconductor device 200, the substrate 14 and the second semiconductor element are further electrically connected via the second wire 98, and the second semiconductor element Waa is sealed with the sealing material 42. Yes. In this case, the reliability of the obtained semiconductor device is further increased.

  The manufacturing method of the semiconductor device according to the present embodiment includes a first die bonding step of electrically connecting the first semiconductor element Wa to the substrate 14 via the first wire 88, and a second semiconductor element Waa. The film adhesive 10 includes a laminating process in which the film adhesive 10 is applied to one surface of the second semiconductor element Waa in accordance with the shape of the second semiconductor element Waa, and the second semiconductor element Waa to which the film adhesive 10 is applied It is placed so as to cover the first semiconductor element Wa, and the film adhesive 10 is pressure-bonded for 0.5 to 3.0 seconds under conditions of 80 to 180 ° C. and 0.01 to 0.50 MPa. A die bonding step of embedding one wire 88 and the first semiconductor element Wa in the film adhesive 10. In this case, the semiconductor device 200 can be manufactured stably.

  Further, in the method for manufacturing a semiconductor device according to the present embodiment, as a process immediately after the die bonding process, the film adhesive 10 is pressurized for 5 minutes or more under the conditions of 60 to 175 ° C. and 0.3 to 0.7 MPa. A heating step is provided. In this case, the remaining slight void can be eliminated in the die-bonding step, so that the semiconductor device can be manufactured more easily while stabilizing the yield.

  The preferred embodiments of the film adhesive, the adhesive sheet, the semiconductor device, and the method for manufacturing the semiconductor device according to the present invention have been described above, but the present invention is not necessarily limited to the above-described embodiment, and the gist thereof is described. Changes may be made as appropriate without departing from.

  In the semiconductor device 200, the substrate 14 is the organic substrate 90 having the circuit patterns 84 and 94 formed on the surface thereof at two locations. However, the substrate 14 is not limited to this, and a metal substrate such as a lead frame is used. Also good.

  Although the semiconductor device 200 has a configuration in which the second semiconductor element Waa is stacked on the first semiconductor element Wa and the semiconductor elements are stacked in two stages, the configuration of the semiconductor device is not limited thereto. I can't. A third semiconductor element may be further stacked on the second semiconductor element Waa, or a plurality of semiconductor elements may be further stacked on the second semiconductor element Waa. As the number of stacked semiconductor elements increases, the capacity of the obtained semiconductor device can be increased.

  In the semiconductor device manufacturing method according to the present embodiment, in the laminating process, the adhesive sheet 100 shown in FIG. 2 is laminated on one side of the semiconductor wafer, and the base film 20 is peeled off, so that the film adhesive 10 is applied. However, the adhesive sheet used at the time of lamination is not limited to this. Instead of the adhesive sheet 100, dicing / die bonding integrated adhesive sheets 120 and 130 shown in FIGS. 4 and 5 can be used. In this case, it is not necessary to attach the dicing tape 60 separately when dicing the semiconductor wafer.

  In the laminating step, not the semiconductor wafer but a semiconductor element obtained by dividing the semiconductor wafer into pieces may be laminated on the adhesive sheet 100. In this case, the dicing process can be omitted.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

(Examples 1-4 and Comparative Examples 1-3)
The product name and composition ratio (unit: part by mass) shown in Table 1 or Table 2 (a) epoxy resin and phenol resin as thermosetting resin, (c) cyclohexanone was added to the composition consisting of inorganic filler and mixed with stirring. . (B) Acrylic rubber as a high molecular weight component is added and stirred as shown in Table 1 or 2, and (e) a coupling agent and (d) curing shown in Table 1 or Table 2 in the same manner. A varnish was obtained by adding an accelerator and stirring until each component was uniform.

  In addition, the symbol of each component in Table 1 and Table 2 means the following.

(Epoxy resin)
R710: (trade name, manufactured by Printec Co., Ltd., bisphenol type epoxy resin, epoxy equivalent 170, liquid at room temperature, weight molecular weight of about 340).
YDF-8170C: (trade name, manufactured by Tohto Kasei Co., Ltd., bisphenol F type epoxy resin, epoxy equivalent 159, liquid at room temperature, weight molecular weight of about 310).
VG3101L: (trade name, manufactured by Printec Co., Ltd., polyfunctional epoxy resin, epoxy equivalent 210, softening point 39-46 ° C.)
SR35K: (trade name, manufactured by Printec Co., Ltd., epoxy resin, epoxy equivalent: 930-940, softening point: 86-98 ° C.).
YDCN-700-10: (trade name, manufactured by Tohto Kasei Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent 210, softening point 75 to 85 ° C.).

(Phenolic resin)
LF-4871: (trade name, manufactured by DIC Corporation, hydroxyl group equivalent 118, water absorption 1 mass%, heating mass reduction rate 4 mass%).
Millex XLC-LL: (trade name, manufactured by Mitsui Chemicals, Inc., phenol resin, hydroxyl group equivalent 175, softening point 77 ° C., water absorption 1 mass%, heating mass reduction rate 4 mass%).
HE200C-10: (trade name, manufactured by Air Water Co., Ltd., phenol resin, hydroxyl group equivalent 200, softening point 65-76 ° C., water absorption 1 mass%, heating mass reduction rate 4 mass%).
HE910-10: (trade name, manufactured by Air Water Co., Ltd., phenol resin, hydroxyl group equivalent 101, softening point 83 ° C., water absorption 1 mass%, heating mass reduction rate 3 mass%).
KA1163 :: (trade name, manufactured by DIC Corporation, phenol resin, hydroxyl group equivalent: 118, softening point: 105 to 115 ° C, heating mass reduction rate 4 mass%)

(Inorganic filler)
SC2050-HLG: (trade name, manufactured by Admatechs Co., Ltd., silica filler dispersion, average particle size 0.50 μm).
SC1030-HJA: (trade name, manufactured by Admatechs Co., Ltd., silica filler dispersion, average particle size of 0.25 μm).
Aerosil R972: (trade name, manufactured by Nippon Aerosil Co., Ltd., silica, average particle size 0.016 μm).

(High molecular weight component)
Acrylic rubber HTR-860P-30B-CHN: (sample name, manufactured by Teikoku Chemical Industry Co., Ltd., weight average molecular weight 230,000, glycidyl functional group monomer ratio 8%, Tg: −7 ° C.).
Acrylic rubber HTR-860P: (sample name, manufactured by Teikoku Chemical Industry Co., Ltd., weight average molecular weight 800,000, glycidyl functional group monomer ratio 3%, Tg: −7 ° C.).

(Coupling agent)
A-1160: (trade name, manufactured by GE Toshiba Corporation, γ-ureidopropyltriethoxysilane).
A-189: (trade name, manufactured by GE Toshiba Corporation, γ-mercaptopropyltrimethoxysilane).

(Curing accelerator)
Cureazole 2PZ-CN: (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd., 1-cyanoethyl-2-phenylimidazole).

  Next, the obtained varnish was filtered through a 100-mesh filter and vacuum degassed. The varnish after vacuum defoaming was applied onto a polyethylene terephthalate (PET) film having a thickness of 38 μm as a base film. The applied varnish was heat-dried in two stages of 90 ° C. for 5 minutes, followed by 140 ° C. for 5 minutes. Thus, an adhesive sheet provided with a film adhesive having a thickness of 60 μm in a B-stage state on a PET film as a base film was obtained.

<Evaluation of various physical properties>
About the film adhesive of the obtained adhesive sheet, shear viscosity, embedment after 175 ° C. pressurization oven curing, tensile modulus after curing, measurement of package warpage, adhesion strength, and evaluation of reflow resistance Went.

[Shear viscosity measurement]
The shear viscosity of the film adhesive was evaluated by the following method.
From the adhesive sheet (thickness 135 μm), the base film was peeled and removed, and punched out to 10 mm square in the thickness direction to obtain a rectangular laminate of 10 mm square and 160 μm thick. A circular aluminum plate jig having a diameter of 8 mm was set in a dynamic viscoelastic device ARES (manufactured by Rheometric Scientific), and a laminate of a film-like adhesive punched out was set here. Thereafter, the temperature was measured while increasing the temperature to 175 ° C. at a temperature increase rate of 5 ° C./min while giving a strain of 5% at 35 ° C., and the temperature at which the shear viscosity value was 5000 Pa · s was recorded.

[Embeddability after 175 ° C pressure oven curing]
The embedding property of the film adhesive after curing at 175 ° C. under pressure oven was evaluated by the following method.
The film-like adhesive (thickness 135 μm) of the adhesive sheet obtained above was attached to a semiconductor wafer (8 inches) having a thickness of 50 μm at 70 ° C. Next, they were diced to 7.5 mm square to obtain semiconductor elements.
Further, FH-SC13-10 (thickness 20 μm) manufactured by Hitachi Chemical Co., Ltd. was attached to a semiconductor wafer (8 inches) having a thickness of 50 μm at 70 ° C. Next, they were diced into 3.0 mm squares to obtain chips.
A chip with FH-SC13-10 separated into pieces is pressure-bonded to a substrate for evaluation having a maximum surface roughness of 6 μm under conditions of 130 ° C., 0.20 MPa, 2 seconds, heated at 120 ° C./2 hours, and semi-cured. I let you.
Next, a 7.5 mm square chip with a film adhesive used in the present invention was pressure-bonded to the sample thus obtained under the conditions of 120 ° C., 0.20 MPa, and 2 seconds. At this time, alignment was performed such that the tip with FH-SC13-10 that was previously crimped was in the middle.
The obtained sample was put into a pressure oven, heated from 35 ° C. to 175 ° C. at a heating rate of 3 ° C./min, and heated at 175 ° C. for 30 minutes.
The sample thus obtained was analyzed with an ultrasonic imaging apparatus SAT (manufactured by Hitachi Construction Machinery, product number FS200II, probe: 25 MHz) to confirm the embeddability. The evaluation criteria for embeddability are as follows.
○: Void ratio is less than 5%.
X: Void ratio is 5% or more.

[Measurement of tensile modulus after curing]
The tensile modulus after curing of the film adhesive was evaluated by the following method.
The substrate film was peeled and removed from the adhesive sheet (thickness: 135 μm), cut into a thickness of 4 mm and a length of 30 mm, and heated in an oven at 120 ° C. for 2 hours and at 170 ° C. for 3 hours. The obtained sample was set in a dynamic viscoelastic device (product name: Rheogel-E4000, manufactured by UMB Co., Ltd.), subjected to a tensile load, measured at a frequency of 10 Hz, and a temperature rising rate of 3 ° C./min, 50 ° C. The measured value at 150 to 260 degrees was recorded. In addition, the maximum temperature at which the value of Tan δ during measurement was maximum was defined as Tg.

[Evaluation of warpage]
The amount of warpage when a chip with adhesive produced using a film adhesive was mounted on a substrate was evaluated by the following method.
A sample was produced in the same manner as the sample obtained in [Evaluation of embeddability after 175 ° C. pressure oven curing]. The obtained sample was cured at 170 ° C. for 3 hours, and then measured with a surface roughness meter over a distance of 8 mm in the diagonal direction of the chip, and the difference between the maximum value and the minimum value of the obtained measurement value was measured before curing. The amount of warpage of the sample was determined. A case where the amount of warpage was 100 μm or less was rated as ◯, and a case where the amount of warp was 100 μm or more was rated as x.

[Measurement of adhesive strength]
The die shear strength (adhesion strength) of the film adhesive was measured by the following method.
First, the film-like adhesive (thickness 135 μm) of the adhesive sheet obtained above was attached to a semiconductor wafer having a thickness of 400 μm at 70 ° C. Next, they were diced to 5.0 mm square to obtain semiconductor elements. A sample was obtained by thermocompression bonding the film-like adhesive side of the separated semiconductor element on a substrate coated with AUS308 under the conditions of 120 ° C., 0.1 MPa, and 5 seconds. Thereafter, the adhesive of the obtained sample was cured by heating at 120 ° C. for 2 hours and at 170 ° C. for 3 hours. Further, the sample after curing of the adhesive was allowed to stand for 168 hours under the conditions of 85 ° C. and 60 RH%. Thereafter, the sample was allowed to stand for 30 minutes under conditions of 25 ° C. and 50% RH, and the die shear strength was measured at 250 ° C., and this was taken as the adhesive strength.

[Evaluation of reflow resistance]
The reflow resistance of the film adhesive was evaluated by the following method.
A sample was produced in the same manner as the sample obtained in [Evaluation of embeddability after 175 ° C. pressure oven curing]. The obtained sample was resin-sealed under the conditions of 175 ° C./6.7 MPa / 90 seconds using a mold sealing material (manufactured by Hitachi Chemical Co., Ltd., trade name “CEL-9750ZHF10), at 175 ° C. The sealing material was cured under conditions of 5 hours to obtain a package.

  Twenty-four packages described above were prepared, and these were exposed to the environment (level 3, 30 ° C., 60 RH%, 192 hours) determined by JEDEC to absorb moisture. Subsequently, the package after moisture absorption was passed through an IR reflow furnace (260 ° C., maximum temperature 265 ° C.) three times. The case where none of the breakage of the package, the change in thickness, the peeling at the interface between the film adhesive and the semiconductor element was observed was evaluated as “◯”, and the case where even one was observed was evaluated as “X”. The results are shown in Tables 3 and 4.

  As is clear from the results shown in Tables 3 and 4, the adhesive sheets of Examples 1 to 4 are excellent in embedding after a 175 ° C. pressure oven as compared with the adhesive sheets of Comparative Examples 1 to 3, It was confirmed that the package warpage after curing was small and the reflow resistance was excellent.

  DESCRIPTION OF SYMBOLS 10 ... Film adhesive, 14 ... Board | substrate, 42 ... Resin (sealing material), 88 ... 1st wire, 98 ... 2nd wire, 200 ... Semiconductor device, Wa ... 1st semiconductor element, Waa ... 1st 2. Semiconductor element.

Claims (8)

A first semiconductor element is wire-bonded to the substrate via a first wire, and a second semiconductor element larger than the area of the first semiconductor element is pressure-bonded on the first semiconductor element. In the semiconductor device thus formed, a film adhesive used for pressure-bonding the second semiconductor element and embedding the first wire and the first semiconductor element,
The elastic modulus at 50 ° C. after curing is 1000 MPa or less, the elastic modulus at 150 ° C. to 260 ° C. after curing is 20 MPa or less, and the glass transition temperature Tg is 150 ° C. or less.
A film adhesive comprising an epoxy resin and a phenol resin.   The film adhesive of Claim 1 in which the said film adhesive contains a high molecular weight component.   The film adhesive of Claim 1 or 2 in which the said epoxy resin contains the epoxy resin which is a liquid at normal temperature.   The film adhesive as described in any one of Claims 1-3 in which the said film adhesive contains an inorganic filler.   The film adhesive as described in any one of Claims 1-4 in which the said epoxy resin contains a phenol novolak-type epoxy resin or a cresol novolak-type epoxy resin.   A dicing die bonding integrated adhesive sheet obtained by laminating the film adhesive according to any one of claims 1 to 5 on a dicing tape.   The dicing / die bonding integrated adhesive sheet according to claim 6, wherein the film adhesive has a thickness of 20 to 200 μm.   The dicing die bonding integrated adhesive sheet according to claim 6 or 7, further comprising a cover film provided on a side surface opposite to a surface on which the dicing tape of the film adhesive is provided.

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