JP2011165761A - Method of manufacturing semiconductor-device and adhesive sheet for circuit-member connection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing semiconductor-device that achieves thinning of a semiconductor element even when the semiconductor element is flip-chip mounted to a wiring circuit board and performs superior resin sealing between the wiring circuit board and the semiconductor element. <P>SOLUTION: The method of manufacturing semiconductor-device includes a step for sticking an adhesive sheet, including a pressure-sensitive adhesive layer 2 and a plastic sheet 1, whose elastic modulus is ≤450 MPa, in this order, onto the surface of a semiconductor wafer 20, having each bump electrode comprising a bump 22 and a solder ball 24 provided thereon, so that the pressure-sensitive adhesive layer 2 embeds the bump electrodes therein; a step for thinning by polishing the face, on the side opposite to the side formed with the bump electrodes of the semiconductor wafer 20; a step for obtaining a semiconductor element with a pressure-sensitive adhesive, by cutting the thinned semiconductor wafer 20 and the pressure-sensitive adhesive layer 2; and a step for obtaining a semiconductor device, having a structure in which a wiring circuit board and the semiconductor element are electrically connected to each other via the solder balls 24, by thermocompression bonding and a pressure-sensitive adhesive 2b seals between the wiring circuit board and the semiconductor element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device and an adhesive sheet for connecting circuit members.

  2. Description of the Related Art As semiconductor devices have recently become more sophisticated, lighter, thinner, and smaller, flip chip mounting has been performed in which semiconductor elements are mounted on a printed circuit board with a face-down structure.

  In flip chip mounting, resin sealing is performed in the gap between the semiconductor element and the printed circuit board in order to protect the semiconductor element. In general flip chip mounting, a pattern is formed on a semiconductor wafer, bumps are formed, the semiconductor wafer is ground to a predetermined thickness, and then cut into individual semiconductor elements. And resin sealing is performed when mounting the obtained semiconductor element on a printed circuit board.

  However, a thinly ground semiconductor wafer has a drawback of low strength against external force. Therefore, as a measure for improvement, there has been proposed a method for compensating for the insufficient strength of the ground semiconductor wafer by grinding the back surface of the semiconductor wafer after resin-sealing the semiconductor wafer with protruding electrodes in advance (for example, the following) (See Patent Document 1).

  On the other hand, when a film-like adhesive is laminated on a semiconductor wafer with protruding electrodes and resin-sealed, there is a problem that voids are generated in the vicinity of the protruding electrode portions and connection reliability is greatly reduced. In Patent Document 2 below, for the purpose of improving the resin embedding property in the protruding electrode part, the support substrate of the thermosetting resin layer is divided into a layer having a small tensile elastic modulus and a layer having a large tensile elastic modulus. A laminated sheet having a layer structure has been proposed.

JP 2001-144123 A Japanese Patent No. 4170839

  However, the laminated sheet described in Patent Document 2 is troublesome and expensive to produce a base material having a two-layer structure, and has a problem in back grindability due to insufficient adhesion between the base materials. . In addition, there is also a problem that the base material and the thermosetting resin layer are firmly attached and the base material is difficult to peel off.

  Conventionally, flip chip mounting has been performed by physical contact called the ACF method, but recently, mounting by the solder bump method has been increasing because it is advantageous for reducing contact resistance and improving connection reliability. Recently, semiconductor devices have been made lighter, thinner, and smaller, and the size of bumps and solder balls provided on semiconductor elements has also been minimized. In the case of such a semiconductor element, resin sealing becomes more difficult, and if there is a void, stress is easily applied to the solder ball, so that connection reliability tends to be lowered.

  The present invention has been made in view of the above circumstances, and even when a semiconductor element is flip-chip mounted on a printed circuit board, the thickness of the semiconductor element can be reduced, and the printed circuit board and the semiconductor element are also provided. It is an object of the present invention to provide a method for manufacturing a semiconductor device capable of obtaining a semiconductor device excellent in connection reliability that can be well sealed with a resin and a circuit member connecting adhesive sheet used therefor.

  In order to solve the above-described problems, the present invention provides an adhesive layer and an elastic layer on a surface of a semiconductor wafer having a protruding electrode formed of a bump and a solder ball provided on the bump. An adhesive sheet comprising a plastic sheet with a rate of 450 MPa or less in this order is attached so that the adhesive layer fills the protruding electrode, and the protruding electrode of the semiconductor wafer to which the adhesive sheet is attached is formed. Polishing the surface opposite to the side to thin the semiconductor wafer, cutting the thinned semiconductor wafer and the adhesive layer to obtain a semiconductor element with an adhesive, and a printed circuit board A semiconductor element with an adhesive is thermocompression bonded onto the wiring circuit board and the semiconductor element via solder balls, and the wiring circuit board and the semiconductor element are sealed with an adhesive. Stopped Obtaining a semiconductor device having a structure, to provide a method of manufacturing a semiconductor device comprising a.

  According to the method of manufacturing a semiconductor device of the present invention, a protruding electrode is formed by laminating the adhesive sheet including a pressure-sensitive adhesive layer and a plastic sheet having a specific elastic modulus on a semiconductor wafer on which the protruding electrode is formed. Viscosity in which the vicinity is sufficiently embedded with adhesive and the tip of the solder ball is exposed from the adhesive or the influence of the adhesive is sufficiently small when connecting the wiring circuit board and the semiconductor element. A semiconductor element with an adhesive can be obtained. As a result, the printed circuit board and the semiconductor element can be electrically connected well and can be well sealed with resin, and a semiconductor device having excellent connection reliability can be obtained. In addition, the method for manufacturing a semiconductor device of the present invention can hold the semiconductor wafer sufficiently by fixing the plastic sheet side when laminating the semiconductor wafer by laminating the adhesive sheet. When cutting, the adhesive layer and the plastic sheet can be easily removed.

  In the method for producing a semiconductor device of the present invention, the adhesive layer has a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, It is preferable to contain a photoinitiator. In this case, when thinning the semiconductor wafer (back grind), hold the semiconductor wafer sufficiently by fixing the plastic sheet side, and then irradiate the adhesive layer with high energy rays such as ultraviolet rays and radiation Then, the adhesive layer is cured to reduce the adhesive force, and the plastic sheet can be easily peeled from the adhesive layer. Moreover, it becomes possible to produce the adhesive sheet which has peelability and reliability by combining the said component.

  In the method for producing a semiconductor device of the present invention, the surface roughness of the plastic sheet on the side of the adhesive layer is preferably 350 nm or less. By using such a plastic sheet, it is possible to more reliably suppress the occurrence of voids in the vicinity of the protruding electrodes due to the surface roughness of the plastic sheet affecting the surface roughness of the adhesive layer.

  In addition, from the viewpoint of sufficiently exposing the tip of the solder ball from the adhesive layer and making a more reliable connection, the thickness of the adhesive layer is smaller than the total height of the bump and the solder ball, and The total thickness of the adhesive layer and the plastic sheet is preferably larger than the total height.

  The present invention is also a circuit member that is used as an adhesive sheet in the method for producing a semiconductor device of the present invention, and includes a plastic sheet having an elastic modulus of 450 MPa or less, and an adhesive layer provided on the sheet. An adhesive sheet for connection is provided.

  According to the adhesive sheet for connecting circuit members of the present invention, even when the semiconductor element is flip-chip mounted on the wiring circuit board, the thickness of the semiconductor element can be reduced, and the space between the wiring circuit board and the semiconductor element can be reduced. A semiconductor device that can be well sealed with resin and has excellent connection reliability can be obtained efficiently.

  In the adhesive sheet for connecting circuit members of the present invention, the adhesive layer comprises a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, And a photoinitiator. In this case, when thinning the semiconductor wafer (back grind), hold the semiconductor wafer sufficiently by fixing the plastic sheet side, and then irradiate the adhesive layer with high energy rays such as ultraviolet rays and radiation Then, the adhesive layer is cured to reduce the adhesive force, and the plastic sheet can be easily peeled from the adhesive layer. Moreover, it becomes possible to produce the adhesive sheet which has peelability and reliability by combining the said component.

  In the adhesive sheet for connecting circuit members of the present invention, the surface roughness of the plastic sheet on the side of the adhesive layer is preferably 350 nm or less. In this case, it is possible to more reliably suppress the occurrence of voids in the vicinity of the protruding electrodes due to the surface roughness of the plastic sheet affecting the surface roughness of the adhesive layer.

  According to the present invention, even when a semiconductor element is flip-chip mounted on a printed circuit board, the thickness of the semiconductor element can be reduced, and the printed circuit board and the semiconductor element can be well sealed with resin. The manufacturing method of the semiconductor device which can obtain the semiconductor device excellent in connection reliability which can be provided, and the adhesive sheet for circuit member connection used therewith can be provided.

FIG. 1 is a schematic cross-sectional view showing an embodiment of an adhesive sheet for connecting circuit members that is preferably used in the method for manufacturing a semiconductor device of the present invention. 2A is a schematic cross-sectional view showing an embodiment of a semiconductor wafer used in the present invention, and FIG. 2B illustrates one step in the method for manufacturing a semiconductor device according to the present invention. It is a schematic cross section for. FIG. 3 is a schematic cross-sectional view for explaining one step in the method of manufacturing a semiconductor device according to the present invention. 4A and 4B are schematic cross-sectional views for explaining one step in the method of manufacturing a semiconductor device according to the present invention. FIG. 5 is a schematic cross-sectional view showing an embodiment of a semiconductor device obtained by the method for manufacturing a semiconductor device according to the present invention. FIG. 6 is a view showing the relationship between the elongation of the sheet and the stress for explaining the elastic modulus of the plastic sheet according to the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to the following embodiments. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1A is a schematic cross-sectional view showing an embodiment of an adhesive sheet for connecting circuit members that is preferably used in the method for manufacturing a semiconductor device of the present invention. First, the adhesive sheet will be described.

  The circuit member connecting adhesive sheet 10 shown in FIG. 1 has a structure in which a first plastic sheet 1, an adhesive layer 2, and a second plastic sheet 3 are laminated in this order. And in the adhesive sheet 10, the elasticity modulus of the 1st plastic sheet 1 is 450 Mpa or less.

  In this specification, the elastic modulus of the first plastic sheet means that a 1 cm × 5 cm sheet is used as a measurement sample, 1 cm on both sides of the sample is fixed, and Tensilon manufactured by Orientec Co., Ltd. is used. When the tensile strength measurement was performed under the conditions of measurement temperature: 25 ° C., measurement speed: 100 mm / min, the relationship of horizontal axis: elongation (%), vertical axis: stress (MPa) was obtained, and the measurement sample was extended by 1 mm ( 3.3%) means the stress B (MPa) corresponding to the intersection of the extension of the normal extending from the point A in the X-axis direction and the tangent with the largest initial inclination (see FIG. 6).

  In addition, the adhesive means a material capable of expressing both functions of the pressure-sensitive adhesive and the adhesive. Specifically, it is a function as a pressure-sensitive adhesive and has a peelability after back grinding and a function as an adhesive. It means something that can exhibit both functions of certain adhesiveness and connection reliability.

  Examples of the first plastic sheet 1 include plastic films such as vinyl acetate and polyolefin films. Among these, a polyethylene film is most preferable in consideration of elongation characteristics. The first plastic sheet 1 may be a mixture of two or more selected from the above materials, or a multilayer of the above film.

  The first plastic sheet 1 preferably has high light transmittance, and specifically, the minimum light transmittance in a wavelength range of 500 to 800 nm is preferably 10% or more. When the adhesive layer 2 is made of a photocurable resin composition, the adhesive layer 2 is irradiated with light from the first plastic sheet 1 side after the semiconductor wafer is thinned (back grinding process), which will be described later. Thus, the first plastic sheet 1 can be easily peeled off.

  The thickness of the first plastic sheet 1 is sufficient to hold the semiconductor wafer in the back grinding process, and to sufficiently suppress the generation of voids when embedding the protruding electrodes of the semiconductor wafer in the adhesive layer 2. 50 to 300 μm is preferable, 60 to 200 μm is more preferable, 70 to 150 μm is still more preferable, and 80 to 150 μm is most preferable. If the thickness of the first plastic sheet 1 is less than 50 μm, voids are likely to occur in the vicinity of the protruding electrodes, and if it exceeds 300 μm, it is not economical.

  The elastic modulus of the first plastic sheet 1 is preferably 100 to 400 MPa from the viewpoint of satisfactorily embedding the protruding electrode of the semiconductor wafer in the adhesive layer 2.

  In the adhesive sheet 10, the surface roughness of the surface of the first plastic sheet 1 on the side of the adhesive layer 2 is preferably 350 nm or less, and more preferably 300 nm or less. Here, the surface roughness of the sheet can be measured using a three-dimensional non-contact surface shape measurement system MM3500 manufactured by Ryoka System. When the first plastic sheet 1 has the above-described surface roughness, generation of voids can be more reliably prevented when the protruding electrode of the semiconductor wafer is embedded in the adhesive layer 2.

  As the second plastic sheet 3, a polymer film having heat resistance and solvent resistance can be used. Examples thereof include plastic films such as a polytetrafluoroethylene film, a polyethylene film, a polypropylene film, and a polymethylpentene film. Further, the second plastic sheet may be a mixture of two or more selected from the above materials, or a multilayer of the above film. More specifically, commercially available products such as polyethylene terephthalate films such as “A-31” manufactured by Teijin DuPont Films, Inc. can be used.

  The thickness of the second plastic sheet 3 is preferably 10 to 100 μm, more preferably 30 to 75 μm, and still more preferably 35 to 50 μm. When the thickness of the second plastic sheet is less than 10 μm, when the adhesive layer 2 is formed on the second plastic sheet by coating, the sheet tends to be torn, and when the thickness exceeds 100 μm, the cost is low. Tend to be inferior.

  In the present embodiment, when the semiconductor wafer is thinned (back grind), the semiconductor wafer is sufficiently held by fixing the first plastic sheet side, and then the first plastic sheet is easily peeled off. Can do.

  Examples of the adhesive layer 2 include, as a base resin, a film-forming resin such as acrylic rubber, polyimide resin, and phenoxy resin, and as a thermosetting resin, an epoxy resin, a bismaleimide resin, a triazine resin, and phenol. What contains thermosetting resin hardened | cured with heat | fever, such as resin, is mentioned. Furthermore, it is preferable that a photoreactive monomer and a photoinitiator are included in order to have a function as a back grind film (a peelability of the plastic film after the back grind). Examples of the photoreactive monomer include “A-DPH” (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). As the photoreactive monomer, it is preferable to select a resin having heat resistance after curing by irradiation with high energy rays such as ultraviolet rays and radiation from the viewpoint of reflowability. Examples of such a photoreactive resin include “A-DPH”, “A-9300” (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.), and the like. The adhesive layer 2 may further include a curing accelerator that reacts with the thermosetting resin. A microcapsule-type latent curing accelerator can be used as the curing accelerator.

  In this embodiment, the adhesive layer 2 includes a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, and a photoinitiator. It is preferable to contain. Examples of the high molecular weight component include film-forming resins such as acrylic rubber, polyimide resin, and phenoxy resin.

  In the present specification, the weight average molecular weight is a value measured by gel permeation chromatography and converted using a standard polystyrene calibration curve.

  As the high molecular weight component, those having a functional group such as a glycidyl group, an acryloyl group, a methacryloyl group, a carboxyl group, a hydroxyl group, and an episulfide group are preferable from the viewpoint of improving adhesion. Examples of such a high molecular weight component include (meth) acrylic ester copolymers and acrylic rubber. In particular, acrylic rubber is more preferable. The acrylic rubber is a rubber mainly composed of an acrylate ester and mainly composed of a copolymer with butyl acrylate and acrylonitrile or a copolymer with ethyl acrylate and acrylonitrile. Examples of the copolymer monomer include butyl acrylate, ethyl acrylate methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylonitrile and the like. Moreover, the high molecular weight component which has a glycidyl group is preferable at a crosslinkable point. Specific examples include a glycidyl group-containing (meth) acrylic copolymer having a weight average molecular weight of 100,000 or more obtained by polymerizing a raw material monomer containing glycidyl acrylate or glycidyl methacrylate. In addition, in this specification, a glycidyl group containing (meth) acryl copolymer is a phrase which shows both a glycidyl group containing acrylic copolymer and a glycidyl group containing methacryl copolymer.

  As the glycidyl group-containing (meth) acrylic copolymer having a weight average molecular weight of 100,000 or more, a glycidyl group-containing (meth) acrylic copolymer prepared by appropriately selecting a monomer from the copolymerization monomer and glycidyl acrylate or glycidyl methacrylate can be used. Commercial products (for example, “HTR-860P-3” manufactured by Nagase ChemteX Corporation) can also be used.

  The acrylic rubber can adjust the crosslink density by appropriately changing the functional group content. When the high molecular weight component is a copolymer of a plurality of monomers, the functional group-containing monomer used as a raw material is preferably contained in an amount of about 0.5 to 6.0% by mass of the copolymer. In the case of a glycidyl group-containing (meth) acrylic copolymer, the repeating unit having a glycidyl group such as glycidyl acrylate or glycidyl methacrylate is preferably 0.5 to 6.0 mass%, more preferably 0.5 to 5.0 mass. %, Even more preferably 0.8 to 5.0% by mass of a glycidyl group-containing (meth) acrylic copolymer is used. When the amount of the repeating unit having a glycidyl group is in the above range, the glycidyl group is slowly crosslinked, and thus it is easy to prevent gelation while securing the adhesive force.

  Examples of the phenoxy resin include a resin obtained by reacting a bifunctional phenol and epichlorohydrin to a high molecular weight or by polyaddition of a bifunctional epoxy resin and a bifunctional phenol. More specifically, the phenoxy resin can be obtained, for example, by reacting a bifunctional phenol and epichlorohydrin in a non-reactive solvent at a temperature of 40 to 120 ° C. in the presence of a catalyst such as an alkali metal hydroxide. it can. Also, phenoxy resins are bifunctional epoxy resins and bifunctional phenols in the presence of catalysts such as alkali metal compounds, organophosphorus compounds, cyclic amine compounds, amides, ethers, and ketones having a boiling point of 120 ° C or higher. It can be obtained by heating to 50 to 200 ° C. in a lactone-based, alcohol-based or other organic solvent under conditions where the reaction solid content is 50 parts by weight or less. Examples of the bifunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, and bisphenol S type epoxy resin. Bifunctional phenols have two phenolic hydroxyl groups, and examples of such bifunctional phenols include bisphenols such as bisphenol A, bisphenol F, bisphenol AD, and bisphenol S. You may use a phenoxy resin individually by 1 type or in combination of 2 or more types.

  Examples of the thermosetting resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, triphenyl Various polyfunctional epoxy resins such as a phenylmethane type epoxy resin and a dicyclopentadiene type epoxy resin can be used. These can be used alone or as a mixture of two or more. More specifically, for example, trade name “1032-H60” manufactured by Japan Epoxy Resin Co., Ltd. and the like can be mentioned. These can be used alone or in combination of two or more.

  Furthermore, a phenol resin can be used for the purpose of improving the heat resistance of the epoxy resin. More specifically, for example, Dainippon Ink & Chemicals, Inc., trade names: Phenolite LF4871, Phenolite VH4170, Nippon Kayaku Co., Ltd., trade name: “DPN-M”, etc. These can be used alone or in combination of two or more.

  Examples of the photoreactive monomer include compounds that can be cross-linked by irradiation with radiation. Specific examples include acrylates such as dipentaerythritol pentaacrylate, isocyanuric acid EO-modified triacrylate, and ditrimethylolpropane tetraacrylate. These compounds can be used alone or in combination of two or more. More specifically, for example, commercially available products such as Shin-Nakamura Industrial Chemical Co., Ltd .: A-DPH, A-9300, Hitachi Chemical Co., Ltd .: FA-512AS, FA-513AS can be used.

  Examples of the photoinitiator include 1-hydroxy-cyclohexyl phenyl ketone and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. Commercial products such as Irg-184 and Irg-819 manufactured by Ciba Specialty Chemicals can be used.

  Microcapsule-type latent curing accelerators include cores composed of curing accelerators, high-molecular substances such as polyurethane, polystyrene, gelatin and polyisocyanate, inorganic substances such as calcium silicate and zeolite, or metal thin films such as nickel and copper. And those substantially covered with a coating such as Examples of the curing accelerator included in the capsule include imidazole and tetraphenylphosphonium tetraphenylborate. Of these, imidazole is preferred in terms of storage stability and fast curability.

  The average particle size of the microcapsules is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of film formability. Moreover, it is preferable that the lower limit of a particle size is 2 micrometers or more from a viewpoint of storage stability.

  A filler may be added to the adhesive layer 2 to such an extent that the light transmittance can be sufficiently maintained from the viewpoint of controlling the fluidity and improving the elastic modulus. Examples of the filler include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, boron nitride, and crystallinity. Examples thereof include composite oxides such as silica, amorphous silica, mullite and cordierite, montmorillonite, and smectite. The shape of the filler is not particularly limited. Said filler can be used individually or in combination of 2 or more types.

  The adhesive layer 2 may further include a coupling agent in order to increase the adhesive strength with the semiconductor wafer. Examples of the coupling agent include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and 3-aminopropylmethyldiethoxysilane. , 3-ureidopropyltriethoxysilane, and 3-ureidopropyltrimethoxysilane. These can be used alone or in combination of two or more. Commercial products such as A-189 and A-1160 manufactured by Nippon Unicar Co., Ltd. can also be used.

  From the viewpoint of improving the connectivity between copper and solder, the adhesive layer 2 may be added with a compound having a carboxylic acid that may remove the copper or solder oxide film. Examples of the compound having a carboxylic acid include adipic acid and diphenolic acid.

  The adhesive layer 2 can contain an ion scavenger from the viewpoint of adsorbing ionic impurities and improving the insulation reliability during moisture absorption. Examples of the ion scavenger include triazine thiol compounds and bisphenol reducing agents, such as compounds known as copper damage inhibitors to prevent copper ionization and dissolution, and zirconium and antimony bismuth magnesium aluminum compounds. And inorganic ion adsorbents.

  As described above, the adhesive layer 2 includes a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, and a photoinitiator. When included, the blending amount of each component is such that the high molecular weight component is 10 to 70% by mass with respect to the total amount of the adhesive layer, and the thermosetting resin is 50 to 600 with respect to 100 parts by mass of the high molecular weight component. It is preferable that the mass part, the curing accelerator is 1 to 30 parts by mass, the photoreactive monomer is 10 to 100 parts by mass, and the photoinitiator is 1 to 10 parts by mass. In addition, content in the case of putting a phenol resin into a thermosetting resin is the equivalent ratio of the phenolic hydroxyl group with respect to the epoxy group of a thermosetting resin from a viewpoint of providing the electric corrosion resistance at the time of moisture absorption 0.5-1.5. It is preferable that it will be 0.8 to 1.2.

  The thickness of the adhesive layer 2 is preferably 5 to 200 μm, more preferably 5 to 150 μm, still more preferably 5 to 100 μm, and particularly preferably 10 to 50 μm. If the thickness of the adhesive layer 2 is less than 5 μm, it tends to be difficult to secure a sufficient adhesive force with the semiconductor wafer, or it becomes difficult to fill the convex electrodes of the circuit board. On the other hand, if the thickness of the adhesive layer 2 is larger than 200 μm, not only is it uneconomical, but depending on the height of the bumps and solder balls provided on the semiconductor wafer, the tips of the solder balls may be sufficiently exposed. This makes it difficult to meet the demand for miniaturization of semiconductor devices.

  In the present embodiment, when the semiconductor wafer is thinned (back grind), the first plastic sheet side is sufficiently held to hold the semiconductor wafer, and then the first plastic sheet is easily peeled off. Furthermore, it is more preferable that the adhesive layer 2 is cured by high energy rays such as ultraviolet rays and radiation or heat (that is, the adhesive force can be reduced). As such an adhesive layer, for example, the above-mentioned acrylic rubber is blended, and a photoreactive monomer such as dipentaerythritol hexaacrylate and a photoinitiator such as 1-hydroxy-cyclohexyl phenyl ketone are further added thereto. And the like.

  The adhesive layer 2 can be formed by preparing a varnish containing the above components and applying the varnish on, for example, a first plastic sheet, a second plastic sheet or other supporting substrate. it can. The solvent for varnishing is not particularly limited as long as it is an organic solvent, but can be determined based on the boiling point in consideration of volatility when producing a film. For example, solvents with relatively low boiling points such as methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, xylene, etc., cure the film during film production. It is preferable in that there is no. These solvents can be used alone or in combination of two or more.

  As a method of applying the varnish on the first plastic sheet, the second plastic sheet or other supporting substrate, knife coating method, roll coating method, spray coating method, gravure coating method, bar coating method, curtain coating Generally known methods such as the method can be mentioned.

  About 70-150 degreeC is preferable for the temperature conditions when removing a solvent from the coating film of a varnish.

  Next, a method for manufacturing a semiconductor device using the above-described adhesive sheet for connecting circuit members will be described.

  2A is a schematic cross-sectional view showing an embodiment of a semiconductor wafer used in the present invention, and FIG. 2B illustrates one step in the method for manufacturing a semiconductor device according to the present invention. It is a schematic cross section for.

  The semiconductor wafer used in the present embodiment is provided with a bump electrode on one surface of the semiconductor wafer 20, which includes bumps 22 and solder balls 24 provided on the bumps 22.

  Examples of the semiconductor wafer 20 include a 6-inch wafer and an 8-inch wafer whose surface has been subjected to an oxide film treatment. Although it does not specifically limit as bump 22, What is comprised with copper, silver, gold | metal | money, etc. is mentioned. Examples of the solder balls 24 include those composed of conventionally known solder materials such as lead-containing solder and lead-free solder.

  The thickness of the semiconductor wafer 20 before thinning can be in the range of 250 to 800 μm. Usually, the cut-out semiconductor wafer has a thickness of 625 to 775 μm in a size of 6 to 12 inches.

  The height of the bump 22 is preferably 5 to 50 μm from the viewpoint of semiconductor miniaturization. The height of the solder ball 24 is preferably 2 to 30 μm from the viewpoint of semiconductor miniaturization.

  In the method for manufacturing a semiconductor device according to the present embodiment, the second plastic sheet is peeled off from the circuit member connecting adhesive sheet 10 and the adhesive contact is formed on the surface of the semiconductor wafer 20 on which the protruding electrodes are formed. The adhesive layer 2 and the first plastic sheet 1 are arranged in this order, and pressure is applied to the semiconductor wafer 20 and the plastic sheet 1 so that the tips of the solder balls 24 penetrate the adhesive layer 2 (FIG. 2). (See (b)). It is most desirable that the tip of the solder ball penetrates the adhesive layer, but the wiring circuit board and the semiconductor element are soldered even if an adhesive layer of about several microns remains on the tip of the solder ball. There is no problem as long as there is no influence on the connectivity when electrically connected via a ball.

  As lamination conditions, a lamination temperature: 50 ° C. to 100 ° C., a linear pressure: 0.5 to 3.0 kgf / cm, and a feed rate: 0.2 to 2.0 m / min are preferable.

  Next, as shown in FIG. 3, a process (back grinding process) of polishing the surface of the semiconductor wafer 20 opposite to the side where the bump electrodes are formed to thin the semiconductor wafer 20 is performed.

  Polishing can be performed using a back grinder. In this step, the semiconductor wafer 20 is preferably thinned to a thickness of 10 to 150 μm. If the thickness of the thinned semiconductor wafer 20 is less than 10 μm, the semiconductor wafer is likely to be damaged. On the other hand, if it exceeds 150 μm, it becomes difficult to meet the demand for downsizing of the semiconductor device.

  Thereafter, as shown in FIG. 4A, the polished surface side of the thinned semiconductor wafer 20 is attached to the dicing sheet 6, and the semiconductor wafer 20 and the adhesive layer 2 are cut using a dicing apparatus. And the semiconductor element with an adhesive agent which consists of the semiconductor element 20a separated into pieces and the cut | disconnected adhesive agent layer 2a is obtained ((b) of FIG. 4). The first plastic sheet 1 is peeled from the adhesive layer 2 before dicing.

  The adhesive-attached semiconductor element thus obtained is manufactured using the adhesive sheet 10 for connecting circuit members, so that the vicinity of the protruding electrode is sufficiently embedded with the adhesive, and the tip of the solder ball is adhesive. It can be sufficiently exposed from the dressing.

  After completion of the dicing process, a semiconductor element with an adhesive is picked up using a pickup device, and this is thermocompression bonded onto the printed circuit board. The conditions for thermocompression bonding are preferably temperature: 150 ° C. to 280 ° C., pressure: 0.1 MPa to 2.0 MPa, and time: 1 second to 30 seconds.

  In this manner, the electrodes 26 of the printed circuit board 7 and the bumps 22 of the semiconductor element 20a shown in FIG. 5 are electrically connected via the solder balls 24, so that the wiring circuit board 7 and the semiconductor element 20a are electrically connected. The semiconductor device 100 having a structure sealed with the adhesive 2b is obtained.

  In the manufacturing method of the semiconductor device according to the present embodiment, the thickness of the adhesive layer 2 is set so that the tip of the solder ball is sufficiently exposed from the adhesive layer to make a more reliable connection. It is preferable that the total height of the adhesive balls 2 and the first plastic sheet 1 is smaller than the total height of the solder balls 24 and larger than the total height.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Examples are described below, but the present invention is not limited to these examples.

<Preparation of adhesive sheet for connecting circuit members>
(Production Example 1)
First, 100 parts by mass of “HTR-860P-3” (trade name, manufactured by Nagase ChemteX Corporation, glycidyl group-containing acrylic rubber, weight average molecular weight 800,000, Tg−7 ° C.), “1032-H60” (cyclohexanone) Japan Epoxy Resin Co., Ltd. trade name, high purity special polyfunctional epoxy resin, epoxy equivalent 169) 160 parts by mass, “DPN-M” (Nippon Kayaku Co., Ltd. trade name, dicyclopentadiene type phenol resin, epoxy Equivalent 175) 140 parts by mass, “A-DPH” (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd., dipentaerythritol hexaacrylate), imidazole compound “2PZ-CN” (Shikoku Kasei Co., Ltd.) as a curing accelerator ) Product name) 3 parts by mass, "Irg-184" as photoinitiator (product name, manufactured by Ciba Specialty Chemicals Co., Ltd.) .5 parts by stirring and mixing by adding further by vacuum degassing, to obtain a pressure-sensitive adhesive varnish.

  Next, the adhesive agent varnish obtained above was dried on a surface release-treated polyethylene terephthalate (manufactured by Teijin DuPont Films Ltd., Teijin Tetron Film: A-31, thickness 50 μm) and the thickness after drying was 30 μm. It was applied so that it was heated and dried at 100 ° C. for 30 minutes to form an adhesive layer. Next, a surface-release-treated polyethylene terephthalate is laminated on the adhesive layer by laminating a light-transmitting plastic sheet having a thickness of 100 μm (manufactured by Ron Seal Co., Ltd., soft polyolefin film, trade name “POF-120A”). An adhesive sheet for connecting circuit members was obtained in which (second plastic sheet) / adhesive layer / soft polyolefin film (first plastic sheet) were laminated in this order.

(Production Example 2)
A circuit member was prepared in the same manner as in Production Example 1 except that a light-transmitting plastic sheet having a thickness of 100 μm (manufactured by Ron Seal Co., Ltd., soft polyolefin film: POF-230A) was used instead of the soft polyolefin film in Production Example 1. An adhesive sheet for connection was obtained.

(Production Example 3)
Instead of the soft polyolefin film in Preparation Example 1, a 100 μm thick plastic sheet having a light transmitting property (manufactured by Thermo Co., Ltd., low density polyethylene / vinyl acetate / low density polyethylene three-layer film: FHF-100) was used. Except that, an adhesive sheet for connecting circuit members was obtained in the same manner as in Production Example 1.

(Production Example 4)
In place of the soft polyolefin film in Production Example 1, a plastic sheet having a thickness of 100 μm (manufactured by NICHIAS, Naflon tape: TOMBO No. 9001) was used in the same manner as in Production Example 1, and an adhesive sheet for connecting circuit members Got.

(Production Example 5)
Circuit member connection adhesion in the same manner as in Production Example 1 except that a plastic sheet (manufactured by Ron Seal Co., Ltd., soft polyolefin film: POF-120A) having a changed surface roughness was used instead of the soft polyolefin film in Production Example 1. A sheet was obtained.

(Production Example 6)
An adhesive sheet for connecting circuit members was obtained in the same manner as in Production Example 1 except that the thickness of the adhesive layer in Production Example 1 was changed to 100 μm.

(Production Example 7)
Instead of the soft polyolefin film in Production Example 1, a light-transmitting plastic sheet having a thickness of 80 μm (manufactured by Teijin DuPont Films Co., Ltd., polyethylene terephthalate teine Tetron film: G2) was used. Thus, an adhesive sheet for connecting circuit members was obtained.

(Production Example 8)
A circuit member was prepared in the same manner as in Production Example 1 except that a light-transmissive plastic sheet having a thickness of 75 μm (manufactured by Tamapoly Co., Ltd., olefin film: OPP) was used instead of the soft polyolefin film in Production Example 1. An adhesive sheet for connection was obtained.

(Production Example 9)
Instead of the soft polyolefin film in Preparation Example 1, a circuit sheet having a light transmittance of 100 μm in thickness was used in the same manner as in Preparation Example 1 except that a plastic sheet (manufactured by Mitsui Chemicals, TPX film: X-22) was used. An adhesive sheet for member connection was obtained.

(Production Example 10)
First, 100 parts by mass of phenoxy resin “FX293” (product name, manufactured by Toto Kasei Co., Ltd.) as the high molecular weight component, and 80 parts by mass of “1032H60” (product name, manufactured by Japan Epoxy Resin Co., Ltd.) as the epoxy resin of the thermosetting resin. And 60 parts by mass of “YL-980” (manufactured by Japan Epoxy Resin Co., Ltd., product name), 80 parts by mass of “A-DPH” (manufactured by Shin-Nakamura Kogyo Co., Ltd., product name) as a photocurable resin, photoinitiator "Irg-184" (product name, manufactured by Ciba Specialty Chemicals Co., Ltd.) 4.0 parts by mass, and "HX-3941HP" (product name, manufactured by Asahi Kasei Chemicals Corporation) 160 parts by mass as a microcapsule type curing accelerator Then, it was dissolved in a mixed solvent of toluene and ethyl acetate to obtain a varnish of an adhesive composition.

  After weighing the obtained varnish, silica particles “SE2050” (manufactured by Admatechs Co., Ltd., product name, average particle size of 0.5 μm) as a filler were added to 100 parts by mass of “FX293” in the varnish. The mixture was added at a ratio of 400 parts by mass, stirred and dispersed. The obtained dispersion was applied on a separator film (PET film, thickness 38 μm) as a supporting substrate using a roll coater, and then dried in an oven at 70 ° C. for 10 minutes. Thus, an adhesive layer having a thickness of 30 μm is formed on the supporting substrate, and then a plastic sheet having a light transmittance of 100 μm on the adhesive layer (manufactured by Ron Seal, soft polyolefin film, trade name “ POF-120A ") is laminated while being heated (40 to 80 ° C), so that the surface release-treated polyethylene terephthalate (second plastic sheet) / adhesive layer / soft polyolefin film (first plastic sheet) ) Were laminated in this order to obtain an adhesive sheet for connecting circuit members.

  About each plastic sheet used by said preparation example, the elasticity modulus and surface roughness were measured in accordance with the following method. The results are shown in Tables 1 and 2.

(1) Measurement of elastic modulus A 1 cm × 5 cm sheet is used as a measurement sample, 1 cm on both sides of the sample is fixed, and using Tensilon manufactured by Orientec Co., Ltd., measurement temperature: 25 ° C., measurement speed: 100 mm / The tensile strength is measured under the conditions of minutes, the relationship between the horizontal axis: elongation (%), the vertical axis: stress (MPa) is determined, and the measurement sample is stretched by 1 mm (3.3%) from point A to the X axis. The stress B (MPa) corresponding to the intersection of the extension of the normal extending in the direction and the tangent with the largest initial inclination was defined as the elastic modulus of the plastic sheet (see FIG. 6).

(2) Measurement of surface roughness (Ra) A measurement sheet is brought into contact with a slide glass via water, and a cut-off value of 4 μm is obtained using a three-dimensional non-contact surface shape measurement system MM3500 manufactured by Ryoka System. Under the above conditions, 10 points on the sheet surface (arbitrary range of about 300 μm × 300 μm) are measured once each, and after the secondary surface correction is applied to the measured image data, an average value of Ra is obtained. Was the surface roughness of the plastic sheet.

<Evaluation of embedding property of bump electrode>
(Examples 1-7)
Using the laminator, the circuit member connecting adhesive sheets obtained in Production Examples 1 to 6 and 10 were each applied to a wafer 1 having the following specifications at 80 ° C., a linear pressure of 1.0 kgf / cm, and a feed rate of 0.5 m / min. I pasted it.
Wafer 1: A semiconductor wafer (8 inches: diameter 150 mm, thickness 150 μm) on which a copper bump with a height of 25 μm is formed and a solder ball with a height of 15 μm is placed on the copper bump.

Thereafter, the presence or absence of voids around the protruding electrode and whether or not the tip of the solder ball penetrates the adhesive layer were confirmed visually and with a microscope. The results are shown in Table 1 with the following symbols.
○: No void is seen, and the tip of the solder ball penetrates the adhesive layer.
Δ1: A small amount of void was seen, but the tip of the solder ball penetrated the adhesive layer.
Δ2: No void is seen, but the tip of the solder ball does not penetrate the adhesive layer.
X: Void is seen and the tip of the solder ball does not penetrate the adhesive layer.

(Example 8)
The adhesive sheet for connecting circuit members obtained in Production Example 1 was attached to a wafer 2 having the following specifications using a laminator at 80 ° C., a linear pressure of 1.0 kgf / cm, and a feed rate of 0.5 m / min.
Wafer 2: A semiconductor wafer (8 inches: diameter 150 mm, thickness 150 μm) on which copper bumps with a height of 35 μm are formed and solder balls with a height of 15 μm are placed on the copper bumps.

  Thereafter, the presence of voids and the penetration of solder balls were confirmed in the same manner as described above. The results are shown in Table 1.

(Comparative Examples 1-3)
The adhesive sheets for connecting circuit members obtained in Production Examples 7 to 9 were respectively attached to the wafer 1 having the above specifications at 80 ° C., a linear pressure of 1.0 kgf / cm, and a feed rate of 0.5 m / min using a laminator. Wearing.

  Thereafter, the presence of voids and the penetration of solder balls were confirmed in the same manner as described above. The results are shown in Table 2.

  DESCRIPTION OF SYMBOLS 1 ... 1st plastic sheet, 2 ... Adhesive agent layer, 3 ... 2nd plastic sheet, 6 ... Dicing tape, 7 ... Wiring circuit board, 10 ... Adhesive sheet for circuit member connection, 20 ... Semiconductor wafer, 20a ... Semiconductor element, 22 ... Bump, 24 ... Solder ball, 26 ... Electrode, 100 ... Semiconductor device.

Claims (10)

A plastic sheet having an adhesive layer and an elastic modulus of 450 MPa or less is placed on the surface of the semiconductor wafer having the bump electrodes and the bump electrodes and the bump electrodes formed on the bumps. Adhering the adhesive sheets in order, the step of sticking the adhesive layer so as to fill the protruding electrodes,
Polishing the surface of the semiconductor wafer on which the adhesive sheet is bonded to the side opposite to the side where the protruding electrodes are formed to thin the semiconductor wafer;
Cutting the thinned semiconductor wafer and the adhesive layer to obtain a semiconductor element with an adhesive; and
The semiconductor element with the adhesive is thermocompression-bonded on the printed circuit board, and the wired circuit board and the semiconductor element are electrically connected via the solder balls, and the wired circuit board and the semiconductor element are Obtaining a semiconductor device having a structure in which a gap is sealed with an adhesive,
A method for manufacturing a semiconductor device.   The adhesive layer contains a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, and a photoinitiator. Item 14. A method for manufacturing a semiconductor device according to Item 1.   The manufacturing method of the semiconductor device of Claim 1 or 2 whose surface roughness by the side of the said adhesive agent layer of the said plastic sheet is 350 nm or less.   The thickness of the adhesive layer is smaller than the total height of the bump and the solder ball, and the total thickness of the adhesive layer and the plastic sheet is larger than the total height. The manufacturing method of the semiconductor device as described in any one of -3. It is used as the adhesive sheet in the method for manufacturing a semiconductor device according to claim 1,
An adhesive sheet for connecting a circuit member, comprising: a plastic sheet having an elastic modulus of 450 MPa or less; and an adhesive layer provided on the sheet.   The adhesive layer contains a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, and a photoinitiator. Item 6. The adhesive sheet for connecting circuit members according to Item 5.   The adhesive sheet for connecting circuit members according to claim 5 or 6, wherein a surface roughness of the plastic sheet on the side of the adhesive layer is 350 nm or less.   An adhesive sheet for connecting a circuit member, comprising: a plastic sheet having an elastic modulus of 450 MPa or less; and an adhesive layer provided on the sheet.   The adhesive layer contains a high molecular weight component having a weight average molecular weight of 20,000 to 1,000,000, a thermosetting resin, a curing accelerator, a photoreactive monomer, and a photoinitiator. Item 9. The adhesive sheet for connecting circuit members according to Item 8.   The adhesive sheet for connecting circuit members according to claim 9, wherein the surface roughness of the plastic sheet on the side of the adhesive layer is 350 nm or less.

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