JP5476673B2 - Adhesive sheet - Google Patents

Description

  The present invention relates to an adhesive sheet used for manufacturing a semiconductor device. More specifically, it is applied at the time of mounting the chip on the substrate by crimping, and is ensured to be embedded in unevenness by melting during the curing process of the sheet. After curing, it has high adhesive strength to the organic substrate and silicon chip. The present invention relates to an adhesive sheet.

  In recent years, stacked MCPs (Multi Chip Packages) in which chips are stacked in multiple stages have become widespread, and they are mounted as memory packages for mobile phones and mobile audio devices, for example. In such applications, with the increasing functionality of cellular phones and the like, higher density and higher integration of packages have been promoted, and multi-stage chips and thinner packages are required. Wire-embedded packages are attracting attention as being able to satisfy these requirements.

  Reliability is one of the important characteristics in the field of mounting substrates on which various electronic components such as stacked MCPs are mounted. For example, whether or not a chip can be mounted without generating a gap on the bonding surface is one factor that affects connection reliability. In particular, in a wire-embedded package, embedding with respect to unevenness when stacking chips on a substrate having unevenness due to wiring, wires, or the like is important. Patent Document 1 discloses an adhesive sheet that is suitable for a manufacturing process of a semiconductor device and can bury unevenness caused by wiring, wires, or the like when a chip is pressure-bonded to a substrate.

  In recent years, in the manufacture of semiconductor devices, in order to achieve miniaturization and thinning of the semiconductor device, thinning of the substrate and wafer has progressed, from the viewpoint of reducing the warping of the element due to the difference in thermal expansion coefficient, There is a strong demand for mounting chips at low temperatures and low loads. However, as the chips are stacked in multiple stages, the surface temperature of the chips that are pressure-bonded to the substrate tends to be lower than the temperature of the substrate close to the heat source, and the upper stage of the package tends to be considerably cooler. As a result, even if it is possible to bury the unevenness only by the low temperature and low load crimp mounting at the lower stage of the package, the upper stage becomes difficult and the unevenness may remain unfilled.

WO05 / 103180 pamphlet

  According to the adhesive film described in Patent Document 1, it is possible to embed irregularities caused by wiring, wires, or the like only by pressure mounting. However, when the disclosed adhesive film is applied to a package whose surface temperature may be lowered due to thinning and multi-stepping, it is difficult to completely bury the unevenness only by crimp mounting. Therefore, there is a demand for a simple method that can reliably fill unevenness caused by wiring, wires, and the like and can provide a highly reliable semiconductor package.

  The present invention has been made in view of the above-described problems, and even if the embedding in the unevenness is insufficient when the chip is pressure-bonded to the substrate, the unfilled portion in the unevenness is embedded in the subsequent process. An object of the present invention is to provide an adhesive sheet having high heat resistance and high moisture resistance that can complete the process.

The present invention is characterized by the following items (1) to (4).
(1) An adhesive sheet composed of a resin composition and melted by being heated to 110 ° C. or higher during the curing process, and having a melt viscosity at 80 ° C. before the curing process of 500 Pa · s or more and 20000 Pa · s. The adhesive sheet is characterized in that the adhesive sheet expands to 110% or more based on the area before the curing treatment by heating during the curing treatment.

  (2) The resin composition has 100 parts by weight of a thermosetting resin, a crosslinkable functional group, a weight average molecular weight of 100,000 to 800,000, and a high molecular weight of Tg of −50 to 50 ° C. An epoxy resin containing 15 to 30 parts by weight of an ingredient and 30 to 70 parts by weight of an inorganic filler having an average particle size of 0.5 μm or more, and the thermosetting resin becomes liquid or softens at 85 ° C. The adhesive sheet according to (1) above, comprising 25% by weight or more and a phenol resin that becomes liquid or softens at 85 ° C. in a range of 35 to 55% by weight.

  (3) The adhesive sheet according to (1) or (2), wherein the adhesive sheet has an adhesive force of 3 MPa or more and a thickness of 5 to 250 μm.

  (4) According to any one of (1) to (3), the unevenness caused by the wire and the unevenness on the substrate or the semiconductor chip can be embedded at the time of crimping mounting at 80 ° C. or by subsequent curing treatment. Adhesive sheet.

  By using the adhesive sheet of the present invention and performing crimp mounting under a temperature condition of 80 ° C. or higher, it is possible to completely bury the unevenness caused by the wiring and wires and the unevenness on the substrate or semiconductor chip. Moreover, even when the crimp mounting is performed at a temperature lower than 80 ° C. and the embedding of the unevenness is insufficient, they are melted and appropriately spread during the curing process of the adhesive sheet of the present invention, so that the unfilled It is possible to complete the embedding in the unevenness in the state. Furthermore, since the adhesive sheet according to the present invention has excellent adhesive strength with respect to the substrate and the chip, and is also excellent in high heat resistance and high moisture resistance, a highly reliable semiconductor device can be applied by applying these adhesive sheets. It becomes possible to provide.

  Details of the present invention will be described below. The adhesive sheet according to the present invention is composed of a resin composition that can be in a completely cured product (C stage) state after a curing process through a semi-cured (B stage) state. In the adhesive sheet according to the present invention, the melt viscosity of the resin composition before the curing treatment is 500 Pa · s or more and 20000 Pa · s or less, more preferably 500 Pa · s or more and 15000 Pa · s or less, more preferably 500 Pa, at 80 ° C. It is characterized by being not less than s and not more than 10,000 Pa · s. In addition, the melt viscosity prescribed | regulated by this invention is the value measured in accordance with the parallel plate plastometer method mentioned later in an Example. Further, the adhesive sheet is characterized by being melted by being heated to at least 110 ° C. during the curing process and spreading to 110% or more based on the area before the curing process.

  When the melt viscosity at 80 ° C. of the resin composition before the curing treatment exceeds 20000 Pa · s, embedding in the unevenness on the substrate becomes insufficient when the chip is pressure-bonded, and a large void tends to remain under the wire. If such a gap is too large, even if the adhesive sheet is melted by heating during the curing process, it tends to be difficult to completely fill the gap. In order to complete the filling of the voids during the curing process, the adhesive sheet is preferably melted at a temperature of 110 ° C. or more and spread to 110% or more, more preferably 120% or more based on the area before the curing process. When the spread of the area of the adhesive sheet at the time of melting is smaller than 110%, there is a high possibility that voids remain under the wires or in the uneven portions. On the other hand, if the melt viscosity at 80 ° C. of the resin composition is less than 500 Pa · s, the adhesive sheet may be excessively melted and flowed out at the time of pressure mounting, and the reliability of the element may be lowered. From the same viewpoint, it is preferable that the upper limit of the area spread of the adhesive sheet when heated to a temperature of 110 ° C. or higher during the curing process is 180%.

  The resin composition constituting the adhesive sheet of the present invention includes a thermosetting resin, a high molecular weight component that appropriately adjusts the viscosity, flexibility, and the like, and an inorganic filler. As one embodiment of the resin composition used in the present invention, it has a crosslinkable functional group with respect to 100 parts by weight of a thermosetting resin, has a weight average molecular weight of 100,000 to 800,000, and Tg is −50. The resin composition which mix | blended 15-30 weight part of high molecular weight components which are -50 degreeC, and the inorganic filler whose average particle diameter is 0.5 micrometer or more in 30-70 weight part is mentioned. Hereinafter, each component will be described.

  The thermosetting resin is not particularly limited, but includes an epoxy resin and a phenol resin as an embodiment from the viewpoint of heat resistance and moisture resistance required when mounting an element in manufacturing a semiconductor device. It is preferable.

  The epoxy resin is not particularly limited as long as it has an adhesive action by a curing treatment. For example, it is possible to use bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and novolak type epoxy resins such as phenol novolac type epoxy resin or cresol novolac type epoxy resin. is there. Moreover, it is also possible to use well-known epoxy resins, such as a polyfunctional epoxy resin, a glycidylamine type epoxy resin, a heterocyclic ring-containing epoxy resin, or an alicyclic epoxy resin.

  Although not particularly limited, an epoxy resin having a molecular weight of 1000 or less is preferable and an epoxy resin having a molecular weight of 500 or less is more preferable from the viewpoint of high flexibility in the B-stage state. Specific examples of the epoxy resin having a molecular weight of 500 or less that is excellent in flexibility include bisphenol A type or bisphenol F type epoxy resin.

  On the other hand, the phenol resin is not particularly limited, but a resin having a low softening point is preferable from the viewpoint of meltability during heating. Similarly, in the B-stage state, the lower the degree of crosslinking is, the better the meltability is, so that a phenol equivalent is preferable.

  The blending amount of the epoxy resin and the phenol resin in the thermosetting resin is preferably 0.70 / 0.30 to 0.30 / 0.70 in terms of an equivalent ratio of epoxy equivalent and hydroxyl equivalent. It is more preferable to set it as 0.65 / 0.35-0.35 / 0.65, and it is still more preferable to set it as 0.60 / 0.40-0.40 / 0.60. Most preferably, the range is 0.60 / 0.40 to 0.50 / 0.50. When the blending ratio of each resin exceeds the upper limit, the curability of the obtained adhesive sheet is lowered, or the viscosity of the adhesive sheet before the curing treatment becomes too high, and the fluidity tends to be inferior.

  In one embodiment of the thermosetting resin, 25 wt% or more, more preferably 30 wt% of an epoxy resin having a melting point or softening point of less than 85 ° C, more preferably less than 80 ° C, based on the total weight of the resin component. On the other hand, it is preferable that a phenol resin having a melting point or softening point of less than 85 ° C., more preferably less than 80 ° C. is contained in the range of 35 to 55% by weight. When the proportion of the epoxy resin is less than 25% by weight, it tends to be difficult to melt. Moreover, when the ratio of the above-mentioned phenol resin is less than 35, curing tends to be insufficient, and when it exceeds 55% by weight, melting tends to be difficult.

  As a more specific embodiment, the thermosetting resin includes an epoxy resin represented by the following general formula (1) and at least one of a phenol resin represented by the following general formulas (2) and (3). It is preferable.

(Wherein R _{1 to} R ₅ represent a hydrogen atom, a linear, branched or cyclic alkyl group, an aralkyl group, an alkenyl group, a hydroxyl group, an aryl group, or a halogen atom, and k, m and n are integers of 1 to 4) P and q indicating the number of repeating units are integers in the range of 0 to 50.)

  The epoxy resin and phenol resin represented by the general formulas (1) to (3) are not particularly limited. However, among the corresponding resins, from the viewpoint of heat resistance and moisture resistance, the water absorption after being put into a constant temperature and humidity chamber at 85 ° C. and 85% RH for 48 hours is 2% by weight or less, respectively. It is preferable to use a resin whose heating mass reduction rate at 350 ° C. measured with an analyzer (TGA) is less than 5% by weight (temperature increase rate: 5 ° C./min, measured in a nitrogen atmosphere).

  Various resins represented by the above general formulas (1) to (3) can be obtained as commercial products. Specific examples of the epoxy resin represented by the general formula (1) include YDF series manufactured by Toto Kasei Co., Ltd. Moreover, as a specific example of the phenol resin represented by the general formula (2), there are Millex XLC-series and XL series manufactured by Mitsui Chemicals. Further, specific examples of the phenol resin represented by the general formula (3) include SN100 series and SN400 manufactured by Toto Kasei Co., Ltd.

  The high molecular weight component used in the present invention is easy to cut at the time of wafer dicing, is difficult to produce resin waste, has high adhesive strength and heat resistance, and further exhibits high fluidity in an uncured state. In view of this, it is preferable that the glass transition temperature (Tg) is −50 to 50 ° C. and the weight average molecular weight is 100,000 to 800,000. As a high molecular weight component, Tg is −20 ° C. to 40 ° C., a weight average molecular weight is preferably 100,000 to 800,000, Tg is −10 ° C. to 40 ° C., and molecular weight is 200,000 to 80 It is more preferable that it is 10,000. The “weight average molecular weight” defined in the present specification indicates a polystyrene-converted value using a standard polystyrene calibration curve according to gel permeation chromatography (GPC).

  If the Tg of the high molecular weight component exceeds 50 ° C., the flexibility of the resin sheet may be lowered. On the other hand, if the Tg is less than −50 ° C., the flexibility of the sheet is too high, so that the sheet is difficult to cut during wafer dicing, and the dicing property may deteriorate due to the generation of burrs. Moreover, when the weight average molecular weight of the high molecular weight component is less than 100,000, the film-forming property may be deteriorated and the adhesive strength and heat resistance of the sheet may be deteriorated. On the other hand, when the weight average molecular weight exceeds 800,000, the fluidity of the uncured sheet may be reduced, and when the adhesive sheet is melted by heating at 110 ° C., the spread of the area does not become 110% or more. May be incompletely embedded.

  The high molecular weight component used in the present invention is not particularly limited as long as it satisfies the above-mentioned characteristics, but a compound having a crosslinkable functional group in the molecule is used in order to develop high heat resistance history. preferable. For example, polyimide resin, (meth) acrylic resin, urethane resin, polyphenylene ether resin, polyetherimide resin, phenoxy having a crosslinkable functional group such as epoxy group, alcoholic or phenolic hydroxyl group, carboxyl group in the molecule. High molecular weight components based on resins, modified polyphenylene ether resins and the like can be used.

  More specifically, it is obtained by copolymerizing a monomer compound having a crosslinkable functional group such as glycidyl acrylate or glycidyl methacrylate and a (meth) acrylic compound, and has a weight average molecular weight of 100,000 to 800,000. There is an epoxy group-containing (meth) acrylic copolymer, which is preferably used. As a (meth) acrylic compound constituting such an epoxy group-containing (meth) acrylic copolymer, a derivative such as (meth) acrylic acid or an ester thereof, or a copolymer thereof can be used. Especially, it is preferable to use the acrylic rubber which has acrylic acid ester as a main component. Specific examples of the acrylic rubber include a copolymer of butyl acrylate and acrylonitrile, a copolymer of ethyl acrylate and acrylonitrile, and the like.

  The high molecular weight component used in the present invention can also be obtained as a commercial product. For example, trade name “acrylic rubber HTR-860P” manufactured by Teikoku Chemical Industry Co., Ltd. can be mentioned. This compound has a glycidyl moiety as a crosslinkable functional group and is based on an acrylic rubber made of ethyl acrylate and the like, and has a weight average molecular weight of 800,000 and a glass transition temperature Tg of −7 ° C.

  The resin composition constituting the adhesive sheet of the present invention is improved in the dicing property of the adhesive sheet in the B-stage state, the handling property of the adhesive sheet, the thermal conductivity is improved, the melt viscosity is adjusted, and the thixotropic property is imparted. The filler is blended for the purpose of improving the adhesive strength. As the filler to be blended, an inorganic filler is preferable. By appropriately blending an inorganic filler with the above-mentioned thermosetting resin and high molecular weight component, the melt viscosity at 80 ° C. of the adhesive sheet before the curing treatment can be adjusted to 500 Pa · s or more and 20000 Pa · s or less. Become.

  In order to impart high fluidity to the adhesive sheet before the curing treatment and further impart appropriate meltability during the curing treatment, the inorganic filler is, for example, 30 to 70 parts by weight with respect to 100 parts by weight of the thermosetting resin. It is preferable to mix | blend in the ratio. When an excessive amount of inorganic filler is present in the resin composition, the fluidity of the adhesive sheet before the curing treatment is lowered, and the meltability at the time of the curing treatment tends to be lowered.

  The average particle diameter of the inorganic filler is 0.5 μm or more, and 99% by weight thereof is preferably distributed in the range of 0.1 to 4.0 μm. An inorganic filler having an average particle diameter of 0.5 μm and 99% by weight distributed in the range of 0.1 to 1.0 μm is more preferable. When an inorganic filler having an average particle size of 0.1 μm or less is used, the fluidity of the adhesive sheet before the curing treatment is lowered due to the increase in the specific surface area and the increase in the number of contained particles, and the meltability during the curing treatment is lowered. There is a case. On the other hand, when a filler having an average particle size of 1.0 μm or more is used, a decrease in the contained particles may cause a decrease in adhesive strength in the adhesive sheet and a deterioration in film formability during sheet preparation.

  The inorganic filler that can be used in the present invention is not particularly limited, and examples thereof include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, and alumina. , Aluminum nitride, aluminum borate whisker, boron nitride, crystalline silica, amorphous silica, antimony oxide, and the like. These can be used alone or in admixture of two or more. In order to improve thermal conductivity, alumina, aluminum nitride, boron nitride, crystalline silica, amorphous silica and the like are preferable. For the purpose of adjusting melt viscosity and imparting thixotropic properties, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, alumina, crystalline silica, non-crystalline silica Crystalline silica and the like are preferable. In order to improve dicing properties, alumina and silica are preferable.

  In addition to the above-mentioned thermosetting resin, high molecular weight component and inorganic filler, the resin composition constituting the adhesive sheet contains various additives such as a curing accelerator, a catalyst, an additive and a coupling agent as necessary. Further, it may be included. Although it does not specifically limit, in order to ensure sufficient elasticity at the time of wire bonding, the resin composition needs to harden | cure rapidly. Therefore, it is preferable that the resin composition which comprises the adhesive sheet of this invention contains a hardening accelerator in addition to the above-mentioned component. Moreover, in order to improve the adhesive force with respect to a board | substrate, it is preferable that a resin composition contains a coupling agent further.

  The adhesive sheet of the present invention is obtained by mixing and kneading a thermosetting resin mainly composed of the above-described epoxy resin, a high molecular weight component, an inorganic filler, and various additives selected as necessary in an organic solvent. It is possible to prepare a varnish-like resin composition, apply this onto a base film to form a varnish layer, and then heat and dry the varnish layer and then remove the base film. . Mixing and kneading can be performed by appropriately combining dispersers such as a normal stirrer, a raking machine, a three-roller, and a ball mill. The above-mentioned heat drying conditions are not particularly limited as long as the used solvent is sufficiently volatilized. Usually, it implements by heating at 60 to 200 degreeC for 0.1 to 90 minutes.

  The substrate film to which the resin composition prepared as a varnish is applied is not particularly limited. For example, polyester film, polypropylene film, polyethylene terephthalate film, polyimide film, polyetherimide film, polyether naphthalate film, methylpentene film Etc. can be used.

  The organic solvent that can be used when preparing the varnish is not particularly limited as long as each component can be uniformly dissolved and kneaded or dispersed, and a known organic solvent can be used. Specific 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 or the like as the organic solvent from the viewpoint that the drying speed is high and the cost is low.

  The film thickness of the adhesive sheet is usually 5 to 250 μm in order to be able to fill irregularities such as a gold wire attached to the wiring circuit of the substrate or the lower layer chip. If the film thickness is thinner than 5 μm, the stress relaxation effect and adhesiveness tend to be poor. On the other hand, if the film thickness is larger than 250 μm, it is not economical and it becomes difficult to meet the demand for downsizing of the semiconductor device. The adhesive sheet of the present invention preferably has an adhesive force to an adherend such as a semiconductor substrate or a chip of 3 MPa or more. Note that the film thickness of the adhesive sheet is preferably 20 to 100 μm, and more preferably 40 to 80 μm from the viewpoint of high adhesiveness and enabling the semiconductor device to be thinned.

  By configuring the adhesive sheet as described above, the unevenness caused by the wiring and wires and the unevenness on the substrate or semiconductor chip can be achieved only by pressure bonding of the chip at 80 ° C. or higher, or by the subsequent curing process of the adhesive sheet. Can be completely embedded. According to the dynamic viscoelasticity measurement, the adhesive sheet is excellent in dicing properties when the storage elastic modulus at 25 ° C. before the curing treatment (B stage state) is in the range of 200 to 6000 MPa, which is preferable. In terms of excellent dicing properties and excellent adhesion to the wafer, the storage elastic modulus is more preferably in the range of 200 to 2000 MPa. If the storage elastic modulus at 80 ° C. in the B-stage state of the adhesive sheet is 0.0001 to 10 MPa, the adhesive sheet can be laminated to the wafer at 80 ° C. In particular, an adhesive sheet having a storage elastic modulus of 0.001 to 5 MPa is more preferable in terms of high adhesion to the wafer. On the other hand, the storage elastic modulus at 170 ° C. after the curing treatment of the adhesive sheet (C stage state) is preferably 5 to 1000 MPa in order to obtain good wire bonding properties.

  The adhesive sheet of the present invention can be used alone, but as an embodiment of the present invention, the adhesive sheet is laminated on a known dicing tape and used as a dicing / die bonding integrated adhesive sheet. It is also possible. By integrating the adhesive sheet and the dicing sheet in this manner, the laminating process on the wafer can be performed once, so that the manufacturing efficiency of the semiconductor device can be increased.

  Examples of the dicing tape that can be used in the present invention 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. If necessary, the dicing tape may be subjected to surface treatment such as primer coating, UV treatment, corona discharge treatment, polishing treatment, and etching treatment.

  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. Such a pressure-sensitive adhesive layer can be formed by applying a well-known resin composition to the surface of a plus chip film and then drying it. It is also possible to use the resin composition of the present invention, in which case the resin composition should have an appropriate tack strength by adjusting the ratio of the liquid component and the Tg of the high molecular weight component. Is preferred.

  When the adhesive sheet of the present invention is applied to the manufacture of a semiconductor device, the adhesive sheet must have an adhesive force that prevents the semiconductor elements from scattering during dicing, and must be peelable from the dicing tape during subsequent pickup. For example, if the adhesive sheet is too sticky, picking up may be difficult. Therefore, it is preferable to appropriately adjust the tack strength of the adhesive sheet. As an adjustment method, it may be used that the adhesive strength and tack strength tend to increase when the flow of the adhesive sheet at room temperature is increased, and that the adhesive strength and tack strength tend to decrease when the flow is decreased. More specifically, when increasing the flow, it can be adjusted by increasing the plasticizer content, increasing the tackifier content, or the like. On the other hand, when the flow is lowered, it can be adjusted by reducing the content of the above-mentioned compounds. Examples of the plasticizer include monofunctional acrylic monomers, monofunctional epoxy resins, liquid epoxy resins, and acrylic resins.

  Examples of the method of laminating the adhesive sheet according to the present invention on the dicing tape include a printing method and a method of pressing or hot roll laminating a previously produced adhesive sheet on the dicing tape. The hot roll laminating method is preferable because it can be continuously manufactured and has high efficiency.

  The film thickness of the dicing tape is not particularly limited, and can be appropriately set based on the knowledge of those skilled in the art depending on the film thickness of the adhesive sheet and the application of the dicing tape-integrated adhesive sheet. Although it does not specifically limit, the film thickness of 60-150 micrometers is preferable and the film thickness of 70-130 micrometers is more preferable at the point which is economical and the handleability of a film is good.

  The adhesive sheet of this invention can be used for manufacture of a semiconductor device. More specifically, after bonding the wafer and the adhesive sheet at 0 ° C. to 80 ° C., the laminate of the wafer and the adhesive sheet was cut using a rotary blade or a laser to obtain a chip with an adhesive sheet. Thereafter, the chip with adhesive can be suitably used for manufacturing a semiconductor device including a step of filling the unevenness by crimping and mounting the uneven chip on a substrate or chip having the unevenness with a load of 0.001 to 1 MPa. .

  When the adhesive sheet is used alone as described above, it is preferable that the dicing tape is subsequently bonded to the adhesive sheet surface after the wafer and the adhesive sheet are bonded together. Alternatively, a dicing / die bonding integrated adhesive sheet in which an adhesive sheet and a dicing tape are bonded in advance can be used. The wafer to be bonded to the adhesive sheet may be composed of single crystal silicon, polycrystalline silicon, various ceramics, compound semiconductors such as gallium arsenide, and the like.

  The temperature at which the adhesive sheet and the wafer are attached, that is, the lamination temperature, is usually 0 to 90 ° C, preferably 15 to 80 ° C, and more preferably 20 to 80 ° C. When the laminating temperature exceeds 90 ° C., the adhesive sheet may be excessively melted, so that the change in the thickness of the adhesive sheet may become significant. When the dicing tape or the dicing / die bonding integrated adhesive sheet is attached, it is preferably performed at the same temperature.

  When using the adhesive sheet of this invention, it is preferable that the load at the time of pressure bonding mounting is 0.01-0.5 MPa, and it is more preferable that it is 0.01-0.3 MPa. When the load is less than 0.001 MPa, the embedding with respect to the unevenness is not sufficient, there are many unfilled portions, and the embedding of the unevenness cannot be completed even by melting of the adhesive sheet by the subsequent curing treatment, resulting in heat resistance. There is a tendency to decrease. On the other hand, when the pressure bonding load exceeds 1 MPa, the chip tends to be damaged.

  Further, when the chip with adhesive is bonded to a substrate having unevenness or the chip, it is desirable to heat the adherend such as the substrate, the chip with adhesive, or both. The heating temperature is preferably 60 to 240 ° C, and more preferably 80 to 180 ° C. When the heating temperature is less than 60 ° C., the embedding property with respect to unevenness tends to be lowered, and when it exceeds 240 ° C., the substrate is deformed and warpage tends to increase. Examples of the heating method include a method of bringing a substrate or chip into contact with a heated hot plate, a method of irradiating the substrate or chip with infrared rays or microwaves, or a method of blowing hot air.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

(Examples 1-3 and Comparative Examples 1-3)
Each component was mixed with the composition shown in Table 1 and Table 2, and the varnish-like resin composition for forming an adhesive sheet was prepared, respectively. In addition, the unit of the composition shown in Table 1 and Table 2 is parts by weight, and details of each component are as follows.

(Epoxy resin)
YSLV-80XY (trade name, manufactured by Toto Kasei Co., Ltd., bisxylenol type epoxy resin, epoxy equivalent 192, melting point 67 ° C.)
YDF-8170C (trade name, manufactured by Toto Kasei Co., Ltd., bisphenol F type epoxy resin, epoxy equivalent 159, liquid at room temperature)
YDCN-700-10 (trade name, manufactured by Toto Kasei Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent 210, softening point 75-85 ° C.)

(Phenolic resin)
Phenolite LF-4871 (Dai Nippon Ink Co., Ltd. trade name, phenol resin, hydroxyl group equivalent 118, softening point 130 ° C.)
Millex XLC-LL (trade name, phenol resin, hydroxyl equivalent 175, softening point 77 ° C., manufactured by Mitsui Chemicals, Inc.)
SN-170L (trade name, phenol resin, hydroxyl equivalent 182 and softening point 70 ° C., manufactured by Toto Kasei Co., Ltd.)

(Inorganic filler)
SC2050-HLG (trade name, silica filler dispersion, average particle size 0.500 μm, manufactured by Admatechs Co., Ltd.)
Aerosil R972 (Nippon Aerosil Co., Ltd. trade name, silica, average particle size 0.016 μm)

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

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

(High molecular weight component)
Acrylic rubber HTR-860P (trade name, Teikoku Chemical Industry Co., Ltd., weight average molecular weight 800,000, Tg-7 ° C)

  With the compositions shown in Tables 1 and 2, the epoxy resin and phenol resin were mixed with the filler, and cyclohexanone was further added and stirred to obtain a uniform mixture. Subsequently, acrylic rubber is added to the mixture and stirred, and then a varnish-like resin composition is prepared by adding a coupling agent and a curing accelerator and stirring until uniform, and subsequently, using a 100 mesh filter. Filtered and vacuum degassed. The varnish-like resin composition thus prepared was applied onto a 38 μm-thick polyethylene terephthalate film (PET) that had been previously subjected to a release treatment. By heating and drying this in two stages of 90 ° C. (5 minutes) and 140 ° C. (5 minutes), a B-stage coating film having a thickness of 40 μm is formed. The prepared adhesive sheet was produced. Next, various properties of each adhesive sheet prepared in each example were evaluated according to the following methods.

[Measurement of melt viscosity]
The melt viscosity was measured according to the parallel plate plastometer method. The specific procedure is shown below. First, three adhesive sheets were laminated at 60 ° C. to give a film thickness of 120 μm, and punched into a circle with a diameter of 6 mm. The circular film was sandwiched between two glass slides having a thickness of 150 μm to prepare a sample. Using a crimping machine set to a predetermined temperature at the time of crimping, the sample was crimped for 3 seconds with a load of 3 kgf, and the melt viscosity was calculated from the change in the area of the adhesive sheet due to the crimping. The results are shown in Tables 3 and 4.

[Method for confirming meltability in curing process]
A sample as shown in FIG. 1 is obtained by first sandwiching an adhesive sheet punched into 10 mm square with an 18 mm square cover glass (thickness 0.15 mm) and laminating it on a hot plate at 60 ° C. so as not to enter air bubbles. Was made. This was the initial state, and the image was captured and saved with a scanner (resolution: 300 pix). Thereafter, the sample was heated at 110 ° C. for 1 hour using an oven, and the state after heating with a scanner (resolution: 300 pix) was captured and stored as an image. The meltability was judged by comparing the change in the area of the adhesive sheet before and after heating. According to the same procedure, the case where the sample was heated at 120 ° C. for 1 hour was also examined. The results are shown in Tables 3 and 4.

[Confirmation of fillability of unfilled parts by melting]
In the wire-embedded package, the unevenness of the wire portion is embedded with an adhesive sheet. However, if the fluidity of the adhesive sheet is insufficient, an unfilled portion of about 30 μm is generated below the wire. In order to confirm the filling property, the pressure bonding is carried out at the pressure bonding temperature at which the temperature of the interface portion of the adhesive sheet (indicated by reference symbol “A” in FIG. 2) is 60 ° C. and 0.04 MPa / 1 s. A sample having an unfilled site under the gold wire as shown in FIG. The initial state of this sample was confirmed by SEM. Subsequently, the sample was put in an oven, heated at 110 ° C. or higher for 1 hour, the state was observed with an SEM, and the filling property was evaluated by comparison with an initial SEM image. 4 and 5 are cross-sectional views schematically showing SEM images. FIG. 4 shows a case where an unfilled portion exists under the wire. On the other hand, FIG. 5 shows a case where the unfilled portion does not exist under the wire and the filling is completed by melting. In the evaluation of filling properties described in Table 3 and Table 4, the case where the SEM image is in the state of FIG. 5 is “◯”, and the case where the SEM image is in the state of FIG.

[Measurement of adhesive strength]
The adhesive strength was evaluated by measuring the die shear strength of the adhesive sheet according to the following procedure. First, the adhesive sheet was attached to a 400 μm thick wafer at 60 ° C. and diced to 5.0 mm square. The chip with the adhesive sheet separated into pieces is pressure-bonded to the surface of the substrate coated with the resist AUS308 under the condition of 120 ° C./250 gf / 1 second to prepare a sample, and then 120 ° C./1 hour, then 170 ° C./1 hour. The adhesive sheet portion was cured by step cure. The sample in which the adhesive sheet portion was cured was allowed to stand for 168 hours under the condition of 85 ° C./60 RH%, and then the die shear strength was immediately measured at 250 ° C., and this was taken as the adhesive strength. The results are shown in Tables 3 and 4.

  As is apparent from the results shown in Tables 3 and 4, the adhesive sheets of the present invention (Examples 1 to 3) are more filled with unfilled sites due to melting than the adhesive sheets of Comparative Examples 1 to 3. It became clear that it was excellent.

It is typical sectional drawing which shows the structure of the sample produced in order to evaluate the meltability in a hardening process in an Example. It is typical sectional drawing explaining the procedure at the time of implementing crimping | bonding mounting using the adhesive sheet of this invention in an Example. It is typical sectional drawing which shows the structure of the sample produced in order to evaluate the filling property by fusion | melting of an adhesive sheet in an Example. It is typical sectional drawing which shows the SEM image of the sample in which an unfilled site | part exists after the fusion | melting of an adhesive sheet in an Example. It is a typical sectional view showing the SEM image of the sample in which an unfilled part does not exist after fusion of an adhesive sheet in an example.

Explanation of symbols

10; Adhesive sheet 12; Slide glass 20; Semiconductor chip 22; Wire 24; Wiring 26; Substrate 30; Unfilled part A;

Claims (2)

An adhesive sheet comprising a thermosetting resin, a resin composition containing an epoxy group-containing (meth) acrylic copolymer having a weight average molecular weight of 100,000 to 800,000, and an inorganic filler,
Each of the thermosetting resins includes an epoxy resin and a phenol resin that are liquid at 85 ° C. or have a melting point or a softening point of less than 85 ° C.,
The melt viscosity at 80 ° C. before the curing treatment of the adhesive sheet is 500 Pa · s or more and 20000 Pa · s or less,
The adhesive sheet spreads at a temperature of 110 ° C. or higher during the curing process,
When the adhesive sheet having a film thickness of 40 μm is punched into a 10 mm square and heated at 120 ° C. for 1 hour, the adhesive sheet after heating spreads to 110% or more based on the area of the adhesive sheet before heating. Adhesive sheet. The resin composition is
100 parts by weight of the thermosetting resin,
15-30 parts by weight of the epoxy group-containing (meth) acrylic copolymer , and 30-70 parts by weight of an inorganic filler having an average particle size of 0.5 μm or more, and the thermosetting resin is the epoxy resin 2. The adhesive sheet according to claim 1, wherein the adhesive sheet contains 25 wt% or more and the phenol resin in a range of 35 to 55 wt%.

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