JP4957064B2 - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet excellent in heat resistance and moisture resistance and exhibiting improved filling properties to an irregular surface subjected to thermal hysteresis when it is used for bonding a semiconductor chip to a supporting member for mounting the semiconductor chip. <P>SOLUTION: The adhesive sheet is employed in a manufacturing process of a semiconductor device comprising a step for bonding a semiconductor chip to a supporting member 20 for mounting the semiconductor chip through an adhesive layer 10 having a modulus of elasticity in tension of 0.1-2 MPa at 170&deg;C when it is hardened by heating 5 hours at 170&deg;C and storage elasticity of 1-6 MPa at 200&deg;C under such a state as an air gap is left between the adhesive layer 10 and the irregular surface of the supporting member 20, and a step for resin sealing the semiconductor chip A1 connected to the supporting member 20 and filling the air gap with the adhesive layer 10. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an adhesive sheet and a semiconductor device obtained using the adhesive sheet.

In recent years, with the miniaturization of semiconductor packages, CSP (Chip Size Package) having a size equivalent to that of a semiconductor chip and a semiconductor device of a type called stacked CSP in which semiconductor chips are stacked in multiple stages have become widespread (for example, patents). Reference 1-5).
JP 2001-279197 A JP 2002-222913 A JP 2002-359346 A JP 2001-308262 A Japanese Patent Laid-Open No. 2004-072009

  Such a package can be manufactured by the following method using an adhesive sheet having an adhesive layer. First, after bonding a semiconductor wafer, an adhesive layer, and a dicing tape at 0 ° C. to 80 ° C., they are simultaneously cut with a rotary blade (dicing step) and washed. Next, the semiconductor chip is bonded to a semiconductor chip mounting support member having an uneven surface via an adhesive layer, and the semiconductor chip is connected to the support member by wire bonding. Thereafter, a process of further stacking the semiconductor chips while bonding them through the adhesive layer and connecting the semiconductor chips to the support member by wire bonding is repeated as necessary. As a result, the semiconductor chips are stacked in multiple stages. Then, after all the steps of connecting by wire bonding are completed, the semiconductor chip is sealed with resin.

  However, when the semiconductor chip is bonded, it is often difficult to completely fill the uneven surface of the support member with the adhesive layer. In particular, when the semiconductor chip is thinner than 210 μm, it is necessary to press-bond with a low load, so that it is extremely difficult to fill the uneven surface.

  Regarding this problem, it is considered effective to fill the uneven surface with the pressure in the process of resin-sealing the semiconductor chip while keeping the uneven surface completely filled with the adhesive layer when bonding the semiconductor chip. . However, when the number of stacked semiconductor chips increases, the adhesive layer is exposed to a high temperature of about 170 ° C. for 1 hour or longer before resin sealing. For this reason, when the number of stacked semiconductor chips increases, the adhesive layer cures before the resin sealing to increase the elastic modulus, and it becomes difficult to sufficiently fill the uneven surface by the pressure in the resin sealing process. There was a problem. If the filling is insufficient, many voids are generated between the adhesive layer and the support member, and the manufacturing yield of the semiconductor device is lowered.

  Further, when the number of stacked semiconductor chips increases, for example, the adhesive layer tends to be peeled off from the support member by high-temperature heating (for example, solder reflow processing) when mounting the semiconductor device. Also from this point, the manufacturing yield of the semiconductor device tends to decrease.

  The present invention has been made in view of the above circumstances, and when used for bonding a semiconductor chip to a support member for mounting a semiconductor chip, the filling property to the uneven surface after receiving a thermal history is provided. An object of the present invention is to provide an adhesive sheet that is improved and also excellent in terms of heat resistance and moisture resistance.

  When the adhesive sheet according to the present invention is cured by heating at 170 ° C. for 5 hours, the tensile elastic modulus at 170 ° C. is 0.1 to 2 MPa, and the storage elastic modulus at 200 ° C. is 1 to 6 MPa. A step of bonding a semiconductor chip to a support member for mounting a semiconductor chip, with a gap left between the adhesive layer and the concavo-convex surface of the support member, and a support member Connecting the semiconductor chip bonded to the support member to the support member by wire bonding, sealing the semiconductor chip connected to the support member with resin, and filling the gap with an adhesive layer between the semiconductor chip and the support member And an adhesive sheet used in a method for manufacturing a semiconductor device.

  The manufacturing method includes one or more steps of laminating a semiconductor chip via an adhesive layer on the side opposite to the supporting member of the semiconductor chip connected to the supporting member, and connecting the semiconductor chip to the supporting member by wire bonding. You may further provide the process.

In the adhesive sheet, the adhesive layer includes an epoxy resin and a resin containing a curing agent thereof and acrylic rubber, and particles having a specific surface area of 30 to 400 m ² / g. The proportion of the total amount of the curing agent is 21 to 26 mass%, the proportion of acrylic rubber is 74 to 79 mass%, and the proportion of particles is preferably 2 to 20 parts by weight with respect to 100 parts by mass of the resin. .

  In the manufacturing method, a chip laminated body in which a semiconductor chip, an adhesive layer, and a dicing tape are laminated in this order is cut out from a laminated body in which the semiconductor wafer, the adhesive layer, and the dicing tape are laminated in this order, and the dicing tape is cut out. There may be further provided a step of removing the substrate to obtain a semiconductor chip with an adhesive layer. In this case, the semiconductor chip with the adhesive layer is placed on the support member, and the semiconductor chip is bonded to the support member by applying pressure at 0.001 to 1 MPa.

  The adhesive sheet according to the present invention may further have a dicing tape bonded to the adhesive layer.

  A semiconductor device according to the present invention includes a support member and one or more semiconductor chips provided on one surface side thereof, and any of the above is provided between the semiconductor chip and the support member and / or between the semiconductor chips. Such an adhesive sheet has an intervening adhesive layer.

  According to the present invention, when used for bonding a semiconductor chip to a support member for mounting a semiconductor chip, the filling property to the uneven surface after receiving a thermal history is improved, and the heat resistance and moisture resistance are improved. An adhesive sheet that is also excellent in terms of properties is provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  FIG. 1 is a cross-sectional view illustrating an embodiment of a semiconductor chip with an adhesive layer and a support member to which the semiconductor chip is bonded. In the method for manufacturing a semiconductor device using the adhesive sheet according to the present embodiment, a gap is formed between the adhesive layer 10 and the concavo-convex surface of the support member 20 through the adhesive layer 10 in the support member 20 for mounting a semiconductor chip. The step of bonding the semiconductor chip A1 in the remaining state (bonding step), the step of connecting the semiconductor chip A1 bonded to the support member 20 to the support member 20 by wire bonding (wire bonding step), and the connection to the support member A step (lamination step) including a step of laminating the semiconductor chip on the side opposite to the support member of the formed semiconductor chip via an adhesive layer and connecting the semiconductor chip to the support member by wire bonding (lamination step); The semiconductor chip A1 connected to the semiconductor chip A1 is resin-sealed and the gap is filled by the adhesive layer 10 between the semiconductor chip A1 and the support member 20. Comprising the step (sealing step), the.

  In the case of the manufacturing method according to the present embodiment, first, a chip in which the semiconductor chip A1, the adhesive layer 10 and the dicing tape are laminated in this order from the laminated body in which the semiconductor wafer, the adhesive layer 10 and the dicing tape are laminated in this order. The laminated body is cut out with a rotary blade, washed and dried to obtain a semiconductor chip 15 with an adhesive layer. The dicing tape is removed as appropriate.

  The laminated body is manufactured, for example, by a method in which a semiconductor wafer, an adhesive layer 10 and a dicing tape are bonded at 0 ° C. to 80 ° C. The adhesive layer may be a single layer or a multilayer. When the adhesive layer is a single layer, the adhesive layer is bonded to the semiconductor wafer, and then a dicing tape is bonded to the adhesive layer. When a multilayer adhesive layer is used, each layer may be bonded to the semiconductor wafer in order, such as the first adhesive layer and the second adhesive layer, or the first adhesive layer and the second adhesive layer may be bonded in advance. An adhesive sheet having a multilayer adhesive layer including an adhesive layer and the like may be prepared and bonded to a semiconductor wafer. Alternatively, a dicing tape-integrated adhesive sheet having a single-layer or multilayer adhesive layer and a dicing tape may be prepared and bonded to a semiconductor wafer.

  The temperature at which the adhesive layer is affixed to the semiconductor wafer, that is, the lamination temperature is preferably 0 to 80 ° C, more preferably 15 to 80 ° C, and further preferably 20 to 70 ° C. If it exceeds 80 ° C., the warp of the semiconductor wafer after the adhesive layer is attached tends to increase.

  Next, the semiconductor chip 15 with the adhesive layer is placed on the support member 20 and pressed at 0.001 to 1 MPa, whereby the unevenness of the adhesive layer 10 and the support member 20 is applied to the support member 20 via the adhesive layer 10. The semiconductor chip A1 is bonded in a state where a gap is left between the surface and the surface. In other words, the semiconductor chip A1 is bonded to the support member 20 via the adhesive layer 10 in a state where the uneven surface of the support member is not completely filled. The load applied at this time is preferably 0.01 to 0.5 MPa, and more preferably 0.01 to 0.3 MPa. If the load is less than 0.001 MPa, the semiconductor chip is easily peeled in the process, and if it exceeds 1 MPa, the semiconductor chip tends to be damaged. Even if the uneven surface after this step is not completely filled, there is no inconvenience due to this, and rather, there is an advantage that blistering hardly occurs because volatile matter is easily removed.

  The semiconductor chip A1 bonded to the support member 20 is electrically connected to the support member 20 by wire bonding.

  Subsequently, a step of stacking the semiconductor chip A1 via the adhesive layer 10 on the side opposite to the support member 20 of the semiconductor chip A1 connected to the support member 20, and connecting the semiconductor chip A1 to the support member 20 by wire bonding. By the process including one or two or more, a multilayer structure in which one or two or more semiconductor chips A1 are stacked is formed. Usually, 1 to 20 semiconductor chips are stacked. In the lamination process, the lowermost adhesive layer 10 interposed between the support member 20 and the semiconductor chip receives a thermal history at 150 to 190 ° C. for about 10 to 300 minutes. However, it is also possible to manufacture a semiconductor device having only the semiconductor chip bonded to the support member via an adhesive layer.

  After all the connections by wire bonding are completed, the plurality of semiconductor chips A1 are sealed with resin, and the whole is covered with sealing resin. At the same time, the adhesive layer 10 interposed between the semiconductor chip A1 and the support member 20 is deformed by the pressure applied at this time, and the gap left between the uneven surface of the adhesive layer 10 and the support member 20 is removed. Fill. Thereby, the uneven surface of the support member is substantially completely filled. That is, a gap having a size that can be detected by ultrasonic flaw detection substantially disappears.

  According to the knowledge of the present inventors, in order to sufficiently fill the uneven surface of the support member 20 in the sealing step, the tensile elastic modulus and storage elastic modulus of the adhesive layer after receiving the thermal history are within a predetermined range. It is effective to adjust so as to be within. Specifically, an adhesive layer having a tensile elastic modulus at 170 ° C. of 0.1 to 2 MPa and a storage elastic modulus at 200 ° C. of 1 to 6 MPa when cured by heating at 170 ° C. for 5 hours. Is used. By heating at 170 ° C. for 5 hours, the adhesive layer is in a C-stage state with a curing degree of 95% or more. A suitable composition for imparting the properties relating to the adhesive layer will be described in detail later.

  The tensile elastic modulus is preferably 0.2 to 1.5 MPa, and more preferably 0.2 to 1 MPa. If this tensile elastic modulus is too low, the heat resistance tends to decrease, and if it is too large, the effect of improving the filling property during resin sealing tends to decrease.

  The storage elastic modulus at 200 ° C. is more preferably 2 to 6 Ma, further preferably 2.5 to 5 MPa, and further preferably 2.5 to 4 MPa.

  From the viewpoint of excellent dicing properties, the storage elastic modulus at 25 ° C. before curing of the adhesive layer (B stage state) is preferably 200 to 3000 MPa. Furthermore, it is more preferable that the storage elastic modulus is 500 to 2000 MPa in terms of excellent dicing properties and excellent adhesion to a semiconductor wafer. Moreover, it is preferable that the storage elastic modulus in 80 degreeC of the contact bonding layer before hardening (B stage state) is 0.1-10 Mpa. Thereby, the favorable laminating property to the semiconductor wafer in the temperature of about 80 degreeC is obtained. In particular, the storage elastic modulus at 80 ° C. is more preferably 0.5 to 5 MPa in terms of high adhesion to a semiconductor wafer.

  The storage elastic modulus of the adhesive layer can be measured using a dynamic viscoelasticity measuring device (such as “DVE-V4” manufactured by Rheology). The measurement conditions are as follows: sample size: length 20 mm, width 4 mm, temperature range −30 to 200 ° C., temperature rising rate 5 ° C./min, tension mode 10 Hz, automatic static load.

  The film thickness of the adhesive layer in the adhesive sheet is preferably 3 to 250 μm in order to fill the uneven surface such as the wiring circuit of the support member. If this film thickness is less than 3 μm, the effect of improving the fillability of the uneven surface tends to be reduced, and the stress relaxation effect and adhesiveness tend to be reduced. If it is thicker than 250 μm, it is not economical and the semiconductor device is downsized. It tends to be difficult to meet the demands. This film thickness is more preferably 20 to 100 μm, and more preferably 30 to 70 μm in terms of high adhesiveness and the ability to reduce the thickness of the semiconductor device.

  The adhesive layer which the adhesive sheet which concerns on this embodiment has consists of resin and particle | grains. The resin is preferably formed from a resin composition containing a thermosetting component that is cured by heating and a high molecular weight component. In the stage where the adhesive layer is bonded to the semiconductor wafer or the semiconductor chip, the adhesive layer is usually in a B stage state.

  The thermosetting component preferably contains an epoxy resin and a curing agent thereof as main components in order to provide the adhesive layer with heat resistance and moisture resistance required for mounting a semiconductor chip.

  The epoxy resin is not particularly limited as long as it cures and exhibits an adhesive action. Specifically, bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin, and novolak type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin are used. be able to. Moreover, what is generally known, such as a polyfunctional epoxy resin, a glycidyl amine type epoxy resin, a heterocyclic ring-containing epoxy resin, or an alicyclic epoxy resin, can be applied.

  In particular, the molecular weight of the epoxy resin is preferably 1000 or less, and more preferably 500 or less in that the flexibility of the adhesive layer in the B-stage state can be increased. 50 to 90 parts by weight of a bisphenol A type or bisphenol F type epoxy resin having a molecular weight of 500 or less and excellent flexibility in a B stage state, and a polyfunctional epoxy resin 10 to 50 having a molecular weight of 800 to 3000 excellent in heat resistance of the cured product It is preferable to use in combination with parts by weight.

  As the curing agent for the epoxy resin, a known curing agent that is usually used can be used. For example, bisphenols having two or more phenolic hydroxyl groups in one molecule such as amines, polyamides, acid anhydrides, polysulfides, boron trifluoride, bisphenol A, bisphenol F, and bisphenol S, phenol novolac resins, bisphenol A Examples thereof include phenolic resins such as novolak resin and cresol novolak resin.

  It is preferable that the ratio of the total amount of the curable component containing the epoxy resin and its curing agent is 10 to 30% by mass. The lower limit of this ratio is preferably 17% by mass, and more preferably 21% by mass. Moreover, it is preferable that an upper limit is 26 mass%, and it is more preferable that it is 25 mass%.

  The high molecular weight component in the adhesive layer preferably has a crosslinkable functional group such as an epoxy group, an alcoholic or phenolic hydroxyl group, or a carboxyl group. Examples of the high molecular weight component having a crosslinkable functional group include (meth) acrylic copolymer ((meth) acrylic resin), polyimide resin, urethane resin, polyphenylene ether resin, polyetherimide resin, phenoxy resin, and modified polyphenylene ether resin. Etc. Among these, a (meth) acrylic copolymer obtained by polymerizing a monomer having a (meth) acrylic group is preferable.

  As the (meth) acrylic copolymer, a (meth) acrylic acid ester copolymer, acrylic rubber or the like can be used, and acrylic rubber is more preferable. Acrylic rubber is a rubber 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.

  The (meth) acrylic copolymer preferably has an acrylic monomer having an epoxy group such as glycidyl acrylate or glycidyl methacrylate as a monomer unit. That is, the (meth) acrylic copolymer (preferably acrylic rubber) preferably has an epoxy group. In this case, the ratio of the acrylic monomer having an epoxy group is preferably 2 to 5% by mass with respect to the total amount of the (meth) acrylic copolymer. When this ratio increases, the crosslinking density increases, and the filling property at the time of resin sealing tends to decrease, and when it is too small, the heat resistance tends to decrease.

  The weight average molecular weight of the high molecular weight component is preferably 100,000 or more and 1,000,000 or less. When the molecular weight is less than 100,000, the heat resistance after curing of the adhesive layer tends to be reduced, and when the molecular weight exceeds 1,000,000, the flow of the adhesive layer tends to be reduced. In addition, the said weight average molecular weight is a polystyrene conversion value using the calibration curve by a standard polystyrene by the gel permeation chromatography method (GPC).

  The glass transition temperature (Tg) of the high molecular weight component is preferably -50 to 50 ° C. In particular, the high molecular weight component has a glass transition temperature (Tg) of − from the point that it becomes easy to cut the adhesive sheet at the time of semiconductor wafer dicing, the resin waste is hardly generated at the time of cutting, and the heat resistance is high. The weight average molecular weight is preferably 100,000 to 900,000 at 20 ° C. to 40 ° C., and the weight molecular weight is more preferably 200,000 to 850,000 with a Tg of −10 ° C. to 40 ° C.

  It is preferable that the ratio of a high molecular weight component is 70-90 mass% with respect to the resin whole quantity. The lower limit of this ratio is preferably 74% by mass, and more preferably 75% by mass. Moreover, it is preferable that an upper limit is 83 mass%, and it is more preferable that it is 79 mass%. If the proportion of the high molecular weight component is less than 70% by mass, the elastic modulus after curing is too high, and therefore it tends to be difficult to fill the uneven surface with the pressure at the time of resin sealing. There is a tendency for heat resistance to be insufficient.

  The resin in the adhesive layer may contain a curing accelerator, a catalyst, an additive, a coupling agent and the like in addition to the above components.

The specific surface area of the particles in the adhesive layer is preferably 30 to 400 m ² / g. As a result, the fluidity and surface smoothness of the adhesive layer are particularly good. Further, when adding a small amount of fine particles, since the high-temperature elastic modulus becomes better packing property as well as increasing the specific surface area is more preferably from 30 to 200 m ² / g, in 70~140m ² / g More preferably it is. In addition, the said specific surface area (BET specific surface area) is the value which made nitrogen adsorb | suck to particle | grains and measured the surface area by Brunauer-Emmett-Teller (Brunauer-Emmett-Teller) type | formula. This BET specific surface area can be measured by a commercially available BET apparatus.

  The ratio of the particles is preferably 2 to 20 parts by weight with respect to 100 parts by weight of the total amount of the resin. If the content of the particles is low, the heat resistance tends to decrease, and if too large, the effect of improving the filling property at the time of resin sealing tends to decrease.

  The particles are preferably inorganic particles. Inorganic particles include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, alumina, aluminum nitride, aluminum borate whisker, boron nitride, crystalline silica, non Examples thereof include crystalline silica and antimony oxide. 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 preferred. In order to improve dicing properties, alumina and silica are preferable.

  The adhesive sheet according to this embodiment is prepared by, for example, mixing and kneading components such as the resin and particles in an organic solvent to prepare a varnish, forming a layer of this varnish on a base film, and drying by heating. Thereafter, it can be obtained by removing the substrate. The above mixing and kneading can be carried out by appropriately combining dispersers such as a normal stirrer, a raking machine, a triple roll, and a ball mill. The heating condition for drying is not particularly limited as long as the solvent used is sufficiently volatilized, but the heating is usually performed at 60 to 200 ° C. for 0.1 to 90 minutes.

  The organic solvent used for the preparation of the varnish is not particularly limited as long as the material can be uniformly dissolved, kneaded or dispersed, and conventionally known ones can be used. Examples of such a solvent include ketone solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, acetone, methyl ethyl ketone, and cyclohexanone, toluene, xylene, and the like. Among these, it is preferable to use methyl ethyl ketone, cyclohexanone, etc. in terms of fast drying speed and low price. Some of these organic solvents usually remain as volatile components in the adhesive layer in the adhesive sheet.

  The organic solvent remaining as a volatile component in the adhesive layer is preferably 0.01 to 3% by weight based on the total mass of the adhesive layer. From the viewpoint of improving heat resistance reliability, this ratio is more preferably 0.01 to 2% by mass, and further preferably 0.01 to 1.5% by mass.

  The adhesive sheet may be composed only of the adhesive layer, or may have a configuration combined with another member such as a support. For example, a dicing tape-integrated adhesive sheet in which one or more adhesive layers are laminated on a conventionally known dicing tape is preferably used. When this dicing tape-integrated adhesive sheet is used, the laminating process on the semiconductor wafer is completed only once, so that the work efficiency can be further improved.

  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. These films may be subjected to surface treatment such as primer application, UV treatment, corona discharge treatment, polishing treatment, etching treatment, etc., as necessary.

  The dicing tape preferably has adhesiveness. Therefore, you may use what gave the adhesiveness to the above-mentioned plastic film, and you may provide an adhesive layer in the single side | surface of the above-mentioned plastic film. The pressure-sensitive adhesive layer can be formed by applying and drying a resin composition having an appropriate tack strength obtained by adjusting the ratio of the liquid component and the Tg of the high molecular weight component.

  When the adhesive sheet is used for manufacturing a semiconductor device, the adhesive layer should have an adhesive force that prevents the semiconductor chip from scattering during dicing, and should be easily peeled off from the dicing tape during subsequent pickup. It is. For example, if the adhesive layer is too sticky, picking up may be difficult. Therefore, it is preferable to appropriately adjust the tack strength of the adhesive layer. For that purpose, if the flow at room temperature of the adhesive layer is increased, the adhesive strength and tack strength tend to increase, and if the flow is decreased, the adhesive strength and tack strength tend to decrease. Good.

  For example, in order to increase the flow, there are methods such as increasing the plasticizer content and increasing the tackifier content. Conversely, in order to reduce the flow, the content of the compound may be reduced. Examples of the plasticizer include monofunctional acrylic monomers, monofunctional epoxy resins, liquid epoxy resins, acrylic resins, and epoxy-based so-called diluents.

  Examples of the method for laminating the adhesive layer on the dicing tape include printing and a method of laminating a previously prepared adhesive layer on the dicing tape by a press or a hot roll. In particular, a method of laminating with a hot roll is preferable because it can be continuously produced and has high efficiency.

  The film thickness of the dicing tape is not particularly limited, and is determined based on the knowledge of those skilled in the art as appropriate depending on the film thickness of the adhesive layer and the use of the adhesive sheet. However, the film thickness is good and the film is easy to handle. In this respect, the thickness is preferably 60 to 150 μm, more preferably 70 to 130 μm.

  As yet another embodiment, the adhesive layer itself may serve as a dicing tape. An adhesive sheet having such an adhesive layer is called a dicing die bond integrated adhesive sheet or the like, and a single sheet serves as both a dicing tape and an adhesive sheet. In order to give such a function to the adhesive sheet, for example, the adhesive layer may contain a photocurable component such as a photocurable high molecular weight component, a photocurable monomer, or a photoinitiator.

  Examples of the semiconductor wafer used in the manufacture of the semiconductor device using the adhesive sheet according to the present embodiment include single crystal silicon, polycrystalline silicon, various ceramics, and compound semiconductors such as gallium arsenide.

  The adhesive sheet according to the present embodiment has a good filling property on the uneven surface formed due to the wiring circuit, and adheres between the semiconductor chip and the support member or between the semiconductor chips in the manufacture of the semiconductor device. Therefore, it can be used as an adhesive sheet having excellent adhesion reliability. The adhesive sheet according to the present embodiment has heat resistance, moisture resistance, insulating properties necessary for mounting a semiconductor chip on a semiconductor element mounting support member, and is excellent in workability.

  FIG. 2 is a cross-sectional view showing an embodiment of a semiconductor device according to the present invention. A semiconductor device 100 shown in FIG. 2 is a package including two or more semiconductor chips of the same size, and is called a so-called stacked CSP. The semiconductor device 100 includes a support member 20 and three semiconductor chips A1 stacked on one surface side of the support member 20. And the adhesive layer 10a formed using the adhesive sheet which concerns on the said embodiment is interposed between semiconductor chip A1 and the supporting member 20, and between semiconductor chips A1. In the adhesive layer 10a, the thermosetting component in the resin is cured.

  The support member 20 includes a substrate 3, a wiring 4 provided on one surface of the substrate 3, and a terminal 5 led out to the other surface side of the substrate 3 through a through hole penetrating the substrate 3 below the wiring 4. Consists mainly of. The surface of the support member 20 on the wiring 4 side has an uneven surface because the wiring 4 is formed. Each semiconductor chip A1 is connected to the wiring 4 through the wire 2.

  In the manufacture of the semiconductor device 100 having such a configuration, an adhesive sheet capable of embedding the uneven surface of the support member 20 and ensuring insulation from the upper semiconductor chip A1 is required.

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

Example 1
36 parts by weight of an epoxy resin “YDCN-703” (trade name, manufactured by Tohto Kasei Co., Ltd., cresol novolak type epoxy resin, epoxy equivalent 210) and a phenol resin “Mirex XLC-LL” (Mitsui Chemicals) as a curing agent for the epoxy resin 30.1 parts by weight (trade name, phenol resin) manufactured by Co., Ltd., and 2.1 parts by weight of “A-1160” (trade name, manufactured by Nihon Unicar Co., Ltd.), which is a silane coupling agent, and “A-189” ( Nippon Unicar Co., Ltd. product name) 1.1 parts by weight and silica filler (particles) “Aerosil R972” (Nippon Aerosil Co., Ltd., average particle size: 0.016 μm, specific surface area 120 m ² / g) Cyclohexanone was added to the composition consisting of 2 parts by weight, mixed with stirring, and then kneaded for 90 minutes using a bead mill.

  200 parts by weight of "HTR-860P-3" (trade name, manufactured by Nagase Chemtex Co., Ltd., weight average molecular weight: 800,000), which is an acrylic rubber containing 3% by mass of a monomer unit derived from glycidyl acrylate or glycidyl methacrylate, And 0.075 parts by weight of “Curazole 2PZ-CN” (trade name, 1-cyanoethyl-2-phenylimidazole, manufactured by Shikoku Kasei Co., Ltd.) as a curing accelerator was added, mixed by stirring, and the varnish of the adhesive composition Got.

  The varnish was applied on a substrate and dried by heating at 90 ° C. for 10 minutes and at 120 ° C. for 5 minutes to form a B-staged adhesive layer (film thickness 40 μm) on the polyethylene terephthalate film. A sheet was obtained. The flow of this adhesive layer was 220 μm. As the substrate, a polyethylene terephthalate film having a thickness of 50 μm and subjected to a release treatment was used.

  The adhesive layer was laminated to a semiconductor wafer (thickness: 80 μm) while heating to 80 ° C., and the edge was cut. Next, a dicing tape was placed on the adhesive layer and laminated at 25 ° C. using a hot roll laminator (Riston manufactured by Du Pont). As the dicing tape, “UC3004M-80” (film thickness: 100 μm) manufactured by Furukawa Electric Co., Ltd. was used.

(Examples 2 and 3)
An adhesive sheet was produced through the same steps as in Example 1 except that the blending ratio was changed as shown in Examples 2 and 3 in Table 1.

(Comparative Examples 1-6)
Except having changed the compounding ratio as shown in Comparative Examples 1-6 of Table 1, the adhesive sheet was produced through the process similar to Example 1. FIG.

  In addition, when melt viscosity (500 micrometers in thickness) of resin used in Examples 1-3 and Comparative Examples 1-3 was measured, it was 20-1 million Pa.s.

(Evaluation)
Evaluation items shown below were evaluated using the adhesive sheets obtained in Examples 1 to 3 and Comparative Examples 1 to 7.

(1) Laminating property An adhesive layer having a width of 10 mm was bonded to a semiconductor wafer by a hot roll laminator (60 ° C., 0.3 m / min, 0.3 MPa). Then, the stress when peeled at an angle of 90 ° at a tensile speed of 50 mm / min in an atmosphere of 25 ° C. was measured to obtain a 90 ° peel strength. As a measuring apparatus, UTM-4-100 type Tensilon manufactured by TOYOBALWIN was used. In this case, when the 90 ° peel strength was 30 N / m or more, the laminate property was good, and when the 90 ° peel strength was less than 30 N / m, the laminate property was poor.

(2) Fillability, reflow crack resistance and temperature cycle resistance Adhesive sheets are bonded to semiconductor wafers, the substrate is peeled off, and a commercially available UV curable dicing tape (Furukawa Electric Co., Ltd., product) Name: UC-334 EP-110). This dicing tape has a pressure-sensitive adhesive layer formed on a substrate, and the pressure-sensitive adhesive layer and the adhesive layer are bonded to each other at the time of bonding. Subsequently, the semiconductor wafer and the adhesive layer were diced using a dicer, and then irradiated with ultraviolet rays (500 J / cm ² ) from the base material side of the dicing tape. After irradiation, the dicing tape was peeled off from the adhesive layer to obtain a semiconductor chip with an adhesive layer.

  The obtained semiconductor chip with an adhesive layer was placed on a support member (a glass epoxy substrate with 5 μm unevenness) provided with wiring in a direction in which the adhesive layer was in close contact with the support member, and heated to 150 ° C. to 0.4 × 9. The semiconductor chip was pressure-bonded to the support member by applying pressure to 8N for 3 seconds. Then, the heat history equivalent to wire bonding was given by the high-temperature heat processing which heats on a 170 degreeC hotplate for 1 hour or 5 hours. Moreover, the sample which did not perform this high temperature heat processing was also prepared.

  Next, an epoxy sealing resin (manufactured by Hitachi Chemical Co., Ltd., trade name: CEL-9700HF) is used for resin sealing under conditions of 180 ° C., 6.75 MPa, 90 seconds, and a semiconductor device sample is manufactured. did. The obtained semiconductor device was humidified under the condition of level 2 (moisture absorption condition: 85 ° C./60% RH, 168 h) defined by JEDEC (Joint Electron Device Engineering Council).

  As a high-temperature reflow test corresponding to Pb-free solder mounting, the process of passing the sample through an IR reflow furnace whose temperature was set so that the maximum temperature of the sample surface was maintained at 260 ° C. for 20 seconds, and cooling by standing at room temperature was repeated twice. .

  For each sample before and after the reflow test, it was confirmed whether or not the adhesive layer was peeled off from the support member using an ultrasonic exploration imaging apparatus. When no cracks, voids, or unfilled portions were generated in all 10 samples, “good” was determined, and when one or more samples were generated, “bad” was determined. In addition, among the results of the above evaluation, it corresponds to the filling property before the reflow test and corresponds to the reflow resistance after the reflow test.

  In addition, for evaluation of temperature cycle resistance, each sample was given a heat history of 1000 cycles, with one cycle being a step of leaving in an atmosphere of −55 ° C. for 30 minutes and then in an atmosphere of 125 ° C. for 30 minutes. And the state of peeling was measured using the ultrasonic survey imaging device. When no peeling occurred in all 10 samples, it was judged as “good”, and when one or more pieces occurred, it was judged as “bad”.

(3) Tensile elastic modulus A test piece cut out to a size of 5 × 30 mm from an adhesive layer cured by heating at 170 ° C. for 1 hour or 5 hours is marked at two locations at intervals of 20 mm, and one end thereof. A weight (W) weight was attached and the suspension was suspended in a high-temperature bath at 170 ° C. The elongation amount ΔL of the film 60 seconds after the introduction was measured, and the cross-sectional area S (= 100 / (20 + ΔL)) of the portion was determined. And high temperature elastic modulus E 'was computed from the relationship of E' = 20 * W / ((DELTA) L * S). The weight load was adjusted so that the elongation of the test piece was less than 5 mm.

(4) Storage elastic modulus About 200 degreeC by the dynamic viscoelasticity measurement using the dynamic viscoelasticity measuring apparatus (Rheology company make, DVE-V4) about the contact bonding layer hardened | cured by heating at 170 degreeC for 1 hour or 5 hours. The storage elastic modulus was measured. The dynamic viscoelasticity measurement was performed under the conditions of sample size: length 20 mm, width 4 mm, temperature range -30 ° C to 200 ° C, heating rate 5 ° C / min, tensile mode 10 Hz, automatic static load.

(5) Peel strength (after curing)
A polyimide film (Upilex S, thickness 50 μm) was laminated on both surfaces of the adhesive layer, and a test piece was prepared by curing the adhesive layer by heating at 170 ° C. for 5 hours. This test piece was cut into a width of 10 mm, and 180 ° peel strength was measured at a speed of 50 mm / min at both ends of the polyimide film in an atmosphere of 25 ° C.

  As is clear from the results shown in Table 1, the adhesive sheets of Examples 1 to 3 exhibit high peel strength and have good filling properties on the uneven surface in resin sealing and reflow resistance. I understand. On the other hand, it can be seen that all of the adhesive sheets of Comparative Examples 1 to 7 are insufficient in filling property or reflow resistance.

  From the above results, it was confirmed that the following effects were exhibited according to the present invention. That is, the adhesive sheet according to the present invention can sufficiently fill the uneven surface of the support member after resin sealing, and has heat resistance and moisture resistance necessary for mounting a semiconductor chip on the support member. It was confirmed that it was excellent in terms. That is, according to the adhesive sheet of the present invention, it is possible to improve the processing speed and yield of the semiconductor device as well as improving the reliability of the semiconductor device.

It is sectional drawing which shows one Embodiment of the semiconductor chip with an adhesive layer, and the supporting member to which this is adhere | attached. It is sectional drawing which shows one Embodiment of the semiconductor device which concerns on this invention.

Explanation of symbols

  A1 ... Semiconductor chip, 2 ... Wire, 3 ... Substrate, 4 ... Wiring, 5 ... Terminal, 10 ... Adhesive layer, 10a ... Adhesive layer (after curing), 20 ... Support member, 100 ... Semiconductor device.

Claims (4)

A support member for semi-conductor chip mounting, when subjected to heat history of 5 hours at 170 ° C., 0.1 to 2 MPa tensile elastic modulus at 170 ° C., and the storage elastic modulus at 200 ° C. and a 1~6MPa via an adhesive layer formed, a step of bonding a semiconductor chip in a state where the gap is left between the uneven surface of the support member and the adhesive layer,
Connecting the semiconductor chip bonded to the support member to the support member by wire bonding;
Filling the gap with a bonding layer between the semiconductor chip and the support member while resin-sealing the semiconductor chip connected to the support member ,
The adhesive layer comprises an epoxy resin, a curing agent thereof, and a resin containing acrylic rubber, and particles having a specific surface area of 30 to 400 m ² / g, the curing agent is a phenol resin, and the particles are silica particles. Yes,
The ratio of the total amount of the epoxy resin and its curing agent is 21 to 26% by mass, and the ratio of the acrylic rubber is 74 to 79% by mass with respect to the total amount of the resin.
The ratio of the particles is 1.8 to 20 parts by weight with respect to 100 parts by weight of the resin.
Production how of the semiconductor device. Before SL via the adhesive layer to the support member and the opposite side of the connected semiconductor chip to a supporting member by stacking a semiconductor chip, a process the semiconductor chip including the step of connecting to the support member 1 or more by wire bonding The manufacturing method according to claim 1, further comprising : Semiconductors wafers, a laminate adhesive layer and the dicing tape are laminated in this order, the semiconductor chip is cut out by the adhesive layer and the laminate chip dicing tape are laminated in this order rotary blade, to remove the dicing tape A step of obtaining a semiconductor chip with an adhesive layer;
Placing the adhesive layer with the semiconductor chip on the support member, bonding the semiconductor chip to the support member by pressurizing with 0.001～1MPa, The method according to claim 1 or 2. The semiconductor device obtained by the manufacturing method as described in any one of Claims 1-3 .

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