JP6634795B2 - Method for manufacturing semiconductor device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  In recent years, there has been an increasing demand for smaller, lighter, and more sophisticated electronic devices. In response to these demands, semiconductor devices constituting electronic devices are also required to be smaller, thinner, and more densely mounted.

  In the manufacture of such a semiconductor device, a semiconductor chip fixed to a substrate or a temporary fixing material is sealed with a sealing resin, and if necessary, the sealed object is turned into a semiconductor device for each electronic component. A dicing procedure is employed. In such a process, in order to meet the above demand, a technique for grinding a sealing body after sealing with a sealing resin to reduce the thickness has been proposed (for example, Patent Documents 1 and 2). reference). In the manufacture of thin semiconductor devices such as a flip chip BGA (Ball Grid Array), a flip chip SiP (System in Package), a fan-in type wafer level package, and a fan-out type wafer level package, in addition to thinning by grinding, The application of a thin semiconductor chip is also an important factor.

Japanese Patent No. 3420748 Japanese Patent No. 3666576

  In a manufacturing process of a thin and high-density semiconductor device such as a fan-out type wafer level package, first, a plurality of thin semiconductor chips are temporarily fixed on a temporary fixing material layer formed on a support, and The semiconductor chip is embedded with a sealing material. Thereafter, a process has been proposed in which a rewiring is formed on the exposed semiconductor chip surface by grinding the sealing material, and then the support with the temporary fixing material layer is separated from the semiconductor chip.

  In the above process, a temporary fixing agent capable of temporarily fixing a thin semiconductor chip with low stress is required.

  An object of the present invention is to provide a method of manufacturing a semiconductor device capable of manufacturing a thin and high-density semiconductor device such as a fan-out type wafer level package with low stress as one means for solving the above problem.

  The present inventors have conducted intensive studies, and as a result, in a method for manufacturing a thin and high-density semiconductor device, by applying a temporary fixing sheet capable of lightening the support by irradiation with radiant energy, The present invention that can be manufactured with low stress has been completed.

  That is, the method for manufacturing a semiconductor device according to the present invention includes a step of laminating a temporary fixing sheet containing a resin composition on a light-transmitting support, and a step of temporarily fixing a semiconductor chip on the temporary fixing sheet. Forming a sealing body covering the temporarily fixed semiconductor chip, grinding the sealing body so that the surface of the semiconductor chip opposite to the light-transmitting support is exposed, and Forming a wiring on the exposed surface of the semiconductor chip; and peeling off the light-transmitting support and the temporary fixing sheet from the semiconductor chip. By irradiating the temporary fixing sheet with radiant energy from the transparent support side, the resin composition of the temporary fixing sheet is decomposed to release the light-transmitting support, and then the semiconductor chip and the sealing are removed. Body Peeling the temporary fixing sheet.

  In the method for manufacturing a semiconductor device, in the step of peeling the temporary fixing sheet, the temporary fixing sheet is irradiated with radiant energy from the light-transmitting support side to decompose the resin composition of the temporary fixing sheet. The light-transmitting support is peeled off. Thus, by decomposing the resin composition of the temporary fixing sheet by irradiation with the radiant energy, the light-transmitting support can be easily separated from the temporary fixing sheet. By applying such a temporary fixing sheet, for example, a thin and high-density semiconductor device such as a fan-out type wafer level package can be manufactured with low stress. In addition, since it is possible to cope with an increase in the area of the light-transmitting support, the manufacturing efficiency of the semiconductor device can be improved.

  Further, in the step of peeling off the temporary fixing sheet, radiant energy may be supplied by a YAG laser that generates light having a wavelength of 1064 nm. In this case, radiant energy can be supplied to the temporary fixing sheet with good cost.

  Further, as the temporary fixing sheet, a laminated sheet having a light-to-heat conversion layer in contact with the light transmitting support and an adhesive layer provided on the light-to-heat conversion layer and temporarily fixing the semiconductor chip is used, and the temporary fixing sheet is laminated. In the step of performing, the temporary fixing sheet may be laminated on the light-transmitting support so that the light-heat conversion layer is in contact with the light-transmitting support and the adhesive layer is located on the opposite side to the light-transmitting support. . In this case, for example, the light-to-heat conversion layer can be made to have a light peeling property with respect to the light-transmitting support, and the adhesive layer can have high-temperature heat history resistance. As a result, it is possible to achieve both light peelability and high-temperature thermal history resistance of the light-transmitting support, which is difficult because of the provisional fixing sheet made of a single resin layer, which is difficult to achieve. Even if a heating process is performed in a step of forming wiring by using such a temporary fixing sheet, thermal destruction of the temporary fixing sheet is suppressed, so that a fan-out type wafer level package is used. A thin, high-density semiconductor device can be manufactured with high reliability.

  Further, a laminated sheet having an adhesive layer containing an inorganic filler may be used as the temporary fixing sheet. In this case, the high-temperature thermal history resistance of the adhesive layer in the temporary fixing sheet is improved.

  According to the present invention, a thin and high-density semiconductor device such as a fan-out type wafer-level package can be reduced in stress by applying a temporary fixing sheet capable of lightly peeling a support and having high-temperature thermal history resistance. It can be manufactured by

FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment. FIG. 5 is a schematic cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. For convenience of the drawings, the dimensional ratios in the drawings do not always match those in the description.

  Hereinafter, a method for manufacturing a semiconductor device according to the present embodiment will be described with reference to FIGS. 1A to 1D, 2A to 2C, and 3A to 3D. As shown in FIG. 1A, first, a light-transmitting support 1 is prepared.

  The light-transmitting support 1 transmits radiant energy 8 (see FIG. 3A) described later and radiates to a light-heat conversion layer 2A (see FIG. 1B) of the temporary fixing sheet 2 described later. It does not hinder the transmission of energy. The transmittance of the radiant energy 8 of the light-transmitting support 1 is, for example, 50% or more. The light-transmitting support 1 is preferably made of a material that maintains a sealed body 4 (see FIG. 2A) to be ground, which will be described later, in a flat state and does not break during a grinding operation and a transport operation described later. . The light-transmitting support 1 preferably has sufficient rigidity to prevent the object to be ground from warping during grinding. Suitable examples of the light-transmitting support 1 include a glass plate or an acrylic plate. The shape and size of the light-transmitting support 1 are not limited, and may be, for example, a wafer shape or a panel (square) shape.

  Next, as shown in FIG. 1B, a temporary fixing sheet 2 is laminated on the light-transmitting support 1. The temporary fixing sheet 2 includes a sheet-shaped light-to-heat conversion layer 2A in contact with the light-transmitting support 1 and an adhesive layer provided on the sheet-shaped light-to-heat conversion layer 2A and located on the opposite side to the light-transmitting support 1. 2B and 2B. The temporary fixing sheet 2 is laminated by using a device such as a vacuum laminator and bonding it to a corresponding surface in a heated and pressurized state.

  The light-to-heat conversion layer 2A has a light absorbing material and a resin composition. The light-to-heat conversion layer 2A can be obtained, for example, by preparing a varnish by dispersing and dissolving a light absorber and a resin composition in an appropriate solvent, and applying the varnish to form a sheet.

  The light absorbing material of the light-to-heat conversion layer 2A absorbs radiant energy 8 (see FIG. 3A) described later. Examples of the light absorbing material include carbon black, carbon fiber, graphite powder, fine metal powder such as iron, aluminum, copper, and nickel, and metal oxide powder such as black titanium oxide. As the light absorbing material, carbon black is preferable. The carbon black significantly reduces the force required for peeling the light-to-heat conversion layer 2A and the light-transmitting support 1 after irradiation with radiant energy 8 described below, and the light-transmitting support 1 is separable from the temporary fixing sheet 2. Can be promoted.

  The thickness of the light-to-heat conversion layer 2A is not particularly limited as long as the light-to-heat conversion layer 2 can be separated from the light-transmitting support 1, but is usually 1 μm to 50 μm. The thickness of the light-to-heat conversion layer 2A is preferably 5 to 25 μm. When the thickness of the light-to-heat conversion layer 2A is less than 1 μm, the concentration of the light absorber required for sufficient light absorption increases. For this reason, the film-forming property of the light-to-heat conversion layer 2 </ b> A is deteriorated, and as a result, poor adhesion between the light-transmitting support 1 and the temporary fixing sheet 2 may occur. On the other hand, when the thickness of the light-to-heat conversion layer 2A exceeds 50 μm, the heat generation of the light-to-heat conversion layer 2A due to radiant energy 8 (see FIG. 3A) described later is not sufficient for the thermal decomposition of the resin composition, There is a possibility that the light-transmitting support 1 may be difficult to peel off from the temporary fixing sheet 2.

  The concentration of the light absorbing agent in the light-to-heat conversion layer 2A also varies depending on the type of light absorbing agent, particle morphology, degree of dispersion and the like. When a general carbon black having a particle size of about 5 to 500 nm is used as the light absorbing material, the concentration of the light absorbing material is usually 5 to 70% by volume, preferably 10 to 60% by volume. Preferably it is 20 to 55% by volume. When the concentration of the light absorbing material is less than 5% by volume, the heat generation of the light-to-heat conversion layer 2A may be insufficient for the thermal decomposition of the resin composition. On the other hand, when the concentration of the light absorbing material exceeds 70% by volume, the film-forming property of the light-to-heat conversion layer 2A is deteriorated, and poor adhesion to other layers is likely to occur. The particle size of the light absorbing material can be determined by heating the temporary fixing sheet in an oven at 600 ° C. for 2 hours to decompose and volatilize the resin component, and observing the residue (eg, inorganic filler or the like) by SEM, or by laser. It can be derived by a method of measuring using a diffraction scattering type particle size distribution measuring device.

  As the resin composition of the light-to-heat conversion layer 2A, an acrylic resin, an epoxy resin, a polyimide resin, a polyamide resin, a polyamideimide resin, a silicone resin, a fluorine resin, or the like can be used. These resin compositions may be used alone or in combination of two or more. In order to further enhance the releasability, a release agent may be added to the resin composition. As a specific example, a long-chain alkyl-based release agent, a silicone-based release agent, or a fluorine-based release agent can be used as the release agent. These release agents may be used alone or in combination of two or more.

  The glass transition temperature (Tg) of the resin composition is desirably 20 ° C to 100 ° C. In this case, the resin composition can prevent re-adhesion (fusion) between cracks separated when cooled after being thermally decomposed by radiant energy 8 (see FIG. 3A) described below, and Hardness that can withstand the sealing body grinding step described below can be maintained. On the other hand, when the Tg of the resin composition exceeds 100 ° C., the temperature at which the light-heat conversion layer 2A is bonded to the light-transmitting support 1 becomes too high, and the light-transmitting support 1 may be warped. Will be expensive. In addition, Tg of the resin composition is determined by using TG-DTA (differential thermogravimetric analyzer), DSC (differential scanning calorimeter), or a film-formed sample as a sample of Rheometric Scientific F.E. It calculates using the viscoelastic analyzer RSA-2 made by a company. When the viscoelasticity analyzer RSA-2 is used, for example, a main dispersion peak when a sample having a thickness of 35 mm × 10 mm × 40 μm is measured at a heating rate of 5 ° C./min, a frequency of 1 Hz, and a measurement temperature of −150 to 300 ° C. The temperature (the temperature at which the tan δ peak is maximum) is defined as Tg.

  The adhesive layer 2B constituting the temporary fixing sheet 2 has adhesiveness and contains a resin composition. The adhesive layer 2B can be obtained by dissolving and dispersing a resin composition (an inorganic filler is added as necessary) in an appropriate solvent to prepare a varnish, and applying the varnish to form a sheet. The thickness of the adhesive layer 2B is preferably 1 μm to 500 μm, more preferably 5 μm to 50 μm.

  As the resin composition of the adhesive layer 2B, an acrylic resin, an epoxy resin, a polyimide resin, a polyamide resin, a polyamideimide resin, a silicone resin, a fluorine resin, or the like can be used. These resin compositions may be used alone or in combination of two or more. In order to further enhance the releasability, a release agent may be added to the resin composition. As a specific example, a long-chain alkyl-based release agent, a silicone-based release agent, and a fluorine-based release agent can be used as the release agent. These release agents may be used alone or in combination of two or more.

  The glass transition temperature (Tg) of the resin composition of the adhesive layer 2B is desirably in the range of −35 ° C. to 50 ° C., and more desirably −10 ° C. to 30 ° C. In this case, the resin composition desirably has an adhesive property capable of temporarily fixing a plurality of semiconductor chips 3 (see FIG. 1C) on the adhesive layer 2B in a temperature range of 20 ° C. to 100 ° C. it can. When the Tg of the resin composition is lower than −35 ° C., the surface tack at the time of forming the adhesive layer 2 </ b> B becomes too strong, and the handleability is likely to be reduced. Further, when the Tg of the adhesive layer 2B exceeds 50 ° C., there is a high possibility that the temperature when the semiconductor chip 3 (see FIG. 1C) is temporarily fixed (temporarily pressed) exceeds 100 ° C.

  The adhesive layer 2B may contain an inorganic filler in addition to the resin composition. In this case, it is possible to further suppress thermal melting due to a high-temperature heat history when forming a sealing body 4 (see FIG. 1D) and a rewiring 5 (see FIG. 2B) to be described later, and temporarily fix. Temperature resistance of the use sheet 2 can be further improved. The inorganic filler is not particularly limited, and various conventionally known fillers can be used. For example, a powder such as fused silica, crystalline silica, alumina, aluminum nitride, silicon nitride, or boron nitride may be used. These inorganic fillers can be used alone or in combination of two or more. When spherical fused silica is used as the inorganic filler, it is preferable from the viewpoints of dispersibility in the resin composition and film forming properties of the adhesive layer 2B. The average particle size of the inorganic filler is preferably in the range of 5 to 500 nm. The average particle size of the inorganic filler can be derived by using a sample arbitrarily extracted from the population and measuring the particle size using a laser diffraction scattering type particle size distribution analyzer.

  Next, as shown in FIG. 1C, a plurality of semiconductor chips 3 are temporarily fixed on the adhesive layer 2B of the temporary fixing sheet 2 formed on the light-transmitting support 1. The plurality of semiconductor chips 3 are individually pressure-bonded and temporarily fixed on the adhesive layer 2B of the temporary fixing sheet 2 under predetermined conditions (for example, at room temperature (20 ° C.) or in a heated state). After the temporary fixing of the semiconductor chip 3, the temporary fixing sheet 2 may be thermally cured under predetermined conditions as necessary. Each of the plurality of semiconductor chips 3 is obtained by cutting a semiconductor wafer into a predetermined size and dividing the semiconductor wafer into chips. The thickness of the semiconductor chip 3 is preferably 1 μm to 1000 μm, more preferably 10 μm to 500 μm, and more preferably 50 μm to reduce the size and thickness of the semiconductor device and also suppress cracking during transportation or a pressing step. 200 μm is more preferred.

  Next, as shown in FIG. 1D, a sealing body 4 that covers the plurality of semiconductor chips 3 temporarily fixed on the temporary fixing sheet 2 is formed. The sealing body 4 is formed using, for example, a sealing sheet. For sealing the semiconductor chip 3 with the sealing body 4 formed from the sealing sheet, for example, a compression sealing molding machine or a vacuum laminating apparatus is used. For example, using the above-described apparatus, heat is applied under the conditions of 40 ° C to 180 ° C (preferably 60 ° C to 150 ° C), 0.1 to 10 MPa (preferably 0.5 to 8 MPa), and 0.5 to 10 minutes. The semiconductor chip 3 is covered with the melted sealing sheet to form a sealing body 4. The sealing sheet may be prepared in a state of being laminated on a release liner such as a polyethylene terephthalate (PET) film. In this case, after the sealing sheet is arranged on the semiconductor chip 3 side and the semiconductor chip 3 is embedded, the sealing body 4 is formed by removing the release liner.

  Although the thickness of the sealing sheet is not particularly limited, it is essential that the thickness of the sealing body 4 be at least the thickness of the semiconductor chip 3 at a minimum. In this case, the thickness of the sealing sheet is 50 μm to 2000 μm, preferably 70 μm to 1500 μm, more preferably 100 μm to 1000 μm in consideration of the thickness of the semiconductor chip 3. When the thickness of the sealing sheet is less than 50 μm, it is necessary to reduce the thickness of the semiconductor chip 3 to be used. In this case, when the semiconductor chip 3 is temporarily fixed and placed on the temporary fixing sheet 2 or when the semiconductor chip 3 is embedded and sealed with a sealing sheet, the semiconductor chip 3 tends to be easily broken. If the thickness of the sealing sheet exceeds 2000 μm, the subsequent steps tend to take a long time, which is not preferable.

  The method for producing the sealing sheet is not particularly limited. For example, a method of preparing a kneaded material of the following resin composition and coating the obtained kneaded material to form a sealing sheet, or a method of plastically processing the obtained kneaded material into a sheet shape and forming the same. Can be

  The resin composition constituting the sealing sheet may be either a thermosetting resin composition or a thermoplastic resin composition. The resin composition is preferably a thermosetting resin composition from the viewpoint of heat resistance and other reliability. In this case, the sealing body 4 can be suitably formed using the above-described device. After the semiconductor chip 3 is covered with the sealing body 4, a heat treatment for the purpose of thermosetting can be performed under predetermined conditions. In this case, the entire sealing body 4 covering the semiconductor chip 3 is heated. As a condition of the thermosetting treatment, the heating temperature is 100 ° C. or higher, preferably 120 ° C. or higher. On the other hand, the upper limit of the heating temperature is 200 ° C or lower, preferably 180 ° C or lower. The heating time is 10 minutes or more, preferably 120 minutes or less.

  Next, as shown in FIG. 2A, the sealing body 4 is ground so that the surface 3a of the embedded semiconductor chip 3 is exposed. The method for grinding the sealing body 4 is not particularly limited, and includes, for example, a grinding method using a high-speed rotating grindstone. The surface 3 a of the semiconductor chip 3 is a surface on the opposite side of the light-transmitting support 1.

  Next, as shown in FIG. 2B, a rewiring (wiring) 5 is formed on the exposed surface 3a of the semiconductor chip 3. As a method of forming the rewiring 5, for example, a metal seed layer is formed on the exposed semiconductor chip 3 using a known method such as a vacuum film forming method, and then a known method such as a semi-additive method is used. And the rewiring 5 can be formed. After the rewiring 5 is formed, an insulating layer such as polyimide or PBO (polybenzoxazole) may be formed on the rewiring 5 and the sealing body. Note that the semi-additive method is to form a metal seed layer, form a resist having a desired pattern on the metal seed layer, increase the thickness of the exposed portion of the metal seed layer by electrolytic plating or the like, and remove the resist. Then, a thin metal seed layer is etched to obtain a wiring.

  Next, as shown in FIG. 2C, a bumping process for forming a bump 6 on the formed rewiring 5 is performed. The bumping process can be performed by a known method using solder balls or solder plating. Hereinafter, an aggregate of the semiconductor chip 3 on which the rewiring 5 and the bumps 6 are formed and the ground sealing body 4 is also referred to as a device forming body 7.

  Next, as shown in FIGS. 3A and 3B, the light-transmitting support 1 and the temporary fixing sheet 2 are peeled from the semiconductor chip 3. The present peeling step includes a step of peeling the temporary fixing sheet 2 from the light-transmitting support 1 and a step of peeling the temporary fixing sheet 2 from the semiconductor chip 3.

  In the step of peeling the temporary fixing sheet 2 from the light transmitting support 1, as shown in FIG. 3A, the radiant energy 8 is applied from the light transmitting support 1 side to the light-to-heat conversion layer 2 </ b> A of the temporary fixing sheet 2. Irradiation. At this time, the radiant energy 8 is absorbed by the light absorber contained in the light-to-heat conversion layer 2A, and the radiant energy 8 is converted to heat energy in the light-to-heat conversion layer 2A. The generated thermal energy rapidly increases the temperature of the light-to-heat conversion layer 2A, whereby the resin composition constituting the light-to-heat conversion layer 2A is thermally decomposed. As a result, voids (voids) are generated in the light-to-heat conversion layer 2A (particularly, in the light-to-heat conversion layer 2A near the interface between the light-to-heat conversion layer 2A and the light-transmitting support 1), and a part of the light-to-heat conversion layer 2A is formed. By disintegration, the light-transmitting support 1 is separated from the temporary fixing sheet 2.

  The radiant energy 8 outputs the wavelength of light absorbed by the light-to-heat conversion layer 2A of the temporary fixing sheet 2, and the light-to-heat conversion layer 2A is melted or thermally decomposed to temporarily fix the light transmitting support 1 to the light transmitting support 1. It is supplied by a laser beam capable of outputting light having sufficient energy to separate the sheet 2 from the sheet 2. Specific examples of the laser light include a YAG laser that generates light with a wavelength of 1064 nm, a double-high gradation YAG laser that generates light with a wavelength of 532 nm, and a semiconductor laser that generates light with a wavelength of 780 nm to 1300 nm. . In view of the scale, versatility, and cost of the laser irradiation device, a YAG laser that generates light having a wavelength of 1064 nm is preferably used as laser light. Regarding the laser irradiation conditions, an output for separating the light-transmitting support 1 and the temporary fixing sheet 2, an output for reducing damage to the semiconductor chip 3, the sealing body 4, and the like, and an output for reducing leakage energy to an adjacent region. Is set in consideration of the balance of

  After peeling the light-transmitting support 1 from the temporary fixing sheet 2 as described above, the pressure-sensitive adhesive layer 2B is peeled off from the device forming body 7 in a vertical direction. For example, after bonding an adhesive tape having a higher adhesive strength than between the device forming body 7 and the adhesive layer 2B to the surface of the temporary fixing sheet 2 opposite to the surface in contact with the device forming body 7, the adhesive tape The adhesive layer 2B and the adhesive layer 2B may be collectively peeled off from the device forming body 7. Thereby, as shown in FIG. 3C, the temporary fixing sheet 2 is removed from the device forming body 7.

  Finally, as shown in FIG. 3D, dicing is performed on a device forming body 7 including elements such as a semiconductor chip 3, a sealing body 4, a rewiring 5, and a bump 6. Specifically, by dicing the sealing body 4 located between the adjacent semiconductor chips 3, the number of the semiconductor chips 3 provided with the rewiring 5 and the bumps 6 is changed. This makes it possible to obtain a semiconductor device in which wiring is drawn out of the chip region.

  As described above, in the method of manufacturing the semiconductor device 10 according to the present embodiment, in the step of peeling the temporary fixing sheet 2, the radiant energy 8 is applied to the temporary fixing sheet 2 from the light-transmitting support 1 side. By irradiation, the resin composition of the temporary fixing sheet 2 is decomposed and the light-transmitting support 1 is peeled off. By decomposing the resin composition of the temporary fixing sheet 2 by irradiation with the radiant energy 8 in this manner, the light-transmitting support 1 can be easily separated from the temporary fixing sheet 2. By applying such a temporary fixing sheet 2, for example, a thin semiconductor device 10 such as a fan-out type wafer level package is embedded with a thin semiconductor chip 3 in a sealing body 4, After the rewiring 5 is formed on the surface 3a of the semiconductor chip 3 exposed by the grinding, the light-transmitting support 1 can be separated from the semiconductor device 10 with low stress. In addition, since it is possible to cope with an increase in the area of the light-transmitting support 1, the manufacturing efficiency of the semiconductor device 10 can be improved.

  In the step of peeling off the temporary fixing sheet 2, the radiant energy 8 may be supplied by a YAG laser that generates light having a wavelength of 1064 nm. In this case, the radiant energy 8 can be supplied to the temporary fixing sheet 2 with good cost.

  Further, as the temporary fixing sheet 2, a laminated sheet having a light-to-heat conversion layer 2A in contact with the light-transmitting support 1 and an adhesive layer 2B provided on the light-to-heat conversion layer 2A and temporarily fixing the semiconductor chip 3 is used. In the step of laminating the temporary fixing sheet 2, the temporary fixing sheet 2 is placed so that the light-to-heat conversion layer 2 </ b> A is in contact with the light-transmitting support 1 and the adhesive layer 2 </ b> B is located on the side opposite to the light-transmitting support 1. It may be laminated on the light transmitting support 1. In this case, the light-to-heat conversion layer 2A can have light peelability with respect to the light-transmitting support 1, and the adhesive layer 2B can have high-temperature heat history resistance. As a result, it is possible to achieve both light peelability and high-temperature thermal history resistance of the light-transmitting support, which is difficult because of the provisional fixing sheet made of a single resin layer, which is difficult to achieve. Even if a heat treatment is performed in the step of forming the rewiring 5 by using such a temporary fixing sheet 2, thermal destruction and the like of the temporary fixing sheet 2 are suppressed. A thin and high-density semiconductor device 10 such as a level package can be manufactured with high reliability.

  Further, as the temporary fixing sheet 2, a laminated sheet having an adhesive layer 2B containing an inorganic filler may be used. In this case, the high-temperature heat history resistance of the adhesive layer 2B in the temporary fixing sheet 2 is improved.

  Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

<Manufacture of temporary fixing sheet>
As shown below, a resin composition for the light-to-heat conversion layer 2A and a resin composition for the pressure-sensitive adhesive layer 2B were respectively prepared to form the temporary fixing sheet 2 on which the light-to-heat conversion layer 2A and the pressure-sensitive adhesive layer 2B were laminated.

<Production of light-to-heat conversion layer sheet>
100 parts by mass of acrylic rubber (HTR-860P-DR3 manufactured by Nagase ChemteX Corporation), 115 parts by mass of cresol novolac type epoxy resin (YDCN-700-10 manufactured by DIC Corporation), phenol aralkyl resin as a curing agent (Mitsui Chemicals Co., Ltd.) 87 parts by mass of a company XLC-LL), 55 parts by mass of a silicone release agent (TA31-209E made by Hitachi Chemical Co., Ltd.), 1 part by mass of a curing accelerator (2PZ-CN made by Shikoku Chemicals Co., Ltd.), carbon black 15 parts by mass (Ketjen Black EC600JD manufactured by Lion Corporation) and 200 parts by mass of cyclohexanone were weighed and stirred to prepare a resin composition for a light-heat conversion layer of a sheet for temporary fixing. Next, the prepared resin composition is applied on a release-treated polyethylene terephthalate (PET) film having a thickness of 50 μm, and is heated and dried at 90 ° C. for 10 minutes and then at 120 ° C. for 30 minutes to obtain a base film. A light-to-heat conversion layer sheet having a thickness of 20 μm was obtained.

<Production of adhesive layer sheet>
100 parts by mass of acrylic rubber (HTR-860P-DR3 manufactured by Nagase ChemteX Corporation), 1 part by mass of curing accelerator (2PZ-CN manufactured by Shikoku Chemicals Co., Ltd.), silicone release agent (TA31 manufactured by Hitachi Chemical Polymer Co., Ltd.) -209E) 20 parts by mass of cyclohexanone and 200 parts by mass of cyclohexanone were weighed and stirred to prepare a resin composition for the adhesive layer of the temporary fixing sheet. Next, the prepared resin composition is applied on a release-treated polyethylene terephthalate (PET) film having a thickness of 50 μm, and is heated and dried at 90 ° C. for 10 minutes and then at 120 ° C. for 30 minutes to obtain a base film. An adhesive layer sheet having a thickness of 20 μm was obtained.

<Preparation of temporary fixing sheet>
The light-to-heat conversion layer sheet with the base film and the adhesive layer sheet with the base film are laminated at 80 ° C. with a roll laminator such that the opposite sides of the base film are in contact with each other. , And a laminated sheet of an adhesive layer, and this was used as a temporary fixing sheet.

<Formation of Temporary Fixing Sheet on Light-Transmissive Support>
First, a non-alkali glass plate having a thickness of 1.0 mm and a size of 9 inches was prepared as the light-transmitting support 1. The temporary fixing sheet was laminated on the glass plate at 80 ° C. with a roll laminator such that the side surface of the light-to-heat conversion layer was in contact with the glass plate to form a temporary fixing sheet on the support. Before the temporary fixing sheet was brought into contact with the glass plate, the substrate film of the light-to-heat conversion layer was peeled off in advance.

<Semiconductor chip mounting (temporary fixing)>
A 200 μm thick semiconductor chip processed to 7.3 mm × 7.3 mm was mounted (temporarily fixed) such that the back surface was bonded to the adhesive layer of the temporary fixing sheet. A flip chip bonder was used for mounting.

<Formation of sealing sheet>
A thermosetting resin composition was prepared as shown below, and a sealing sheet was formed. Specifically, 70 parts by mass of a cresol novolac type epoxy resin (manufactured by DIC Corporation, product name: Epicron N660) as an epoxy resin and a phenoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., product name: YP -55) 100 parts by mass, 30 parts by mass of a melamine-modified phenol novolak resin (manufactured by DIC Corporation, product name: LA7054), and 200 parts by mass of barium sulfate as an inorganic filler component were mixed with zirconia beads having a diameter of 1.0 mm. Using a Star Mill LMZ (manufactured by Ashizawa Finetech Co., Ltd., “Star Mill” is a registered trademark), the mixture was dispersed at a peripheral speed of 12 m / s for 3 hours to prepare a thermosetting resin composition.

  Barium sulfate having an average particle size of 300 nm was used as the inorganic filler component. The dispersion state of the inorganic filler in the thermosetting resin composition is determined by a dynamic light scattering type nanotrack particle size distribution analyzer “UPA-EX150” (manufactured by Nikkiso Co., Ltd.) and a laser diffraction scattering type microtrack particle size distribution meter “MT-3100”. (Manufactured by Nikkiso Co., Ltd.), and it was confirmed that the maximum particle size of the inorganic filler was 2 μm or less.

  The solution of the thermosetting resin composition obtained as described above is uniformly applied on a 16 μm-thick polyethylene terephthalate film (manufactured by Teijin Limited, trade name: G2-16), which is a support layer, so that thermosetting is performed. A conductive resin composition layer was formed. Thereafter, the thermosetting resin composition layer was dried at 100 ° C. for about 10 minutes using a hot air convection dryer to obtain a sealing film having a thickness of 50 μm on the support layer.

  Then, a polyethylene film (trade name: NF-15, manufactured by Tamapoly Co., Ltd.) is bonded as a protective film on the surface opposite to the side in contact with the support layer so that dust and the like do not adhere to the sealing film. Thus, a sealing sheet was formed.

<Compression sealing>
The obtained sealing sheet was processed into a 6-inch size, and a sealing sheet was formed on the semiconductor chip temporarily fixed on the temporary fixing sheet. Specifically, first, only the protective film of the thermosetting resin film made of the thermosetting resin composition was peeled off, and the sealing sheet was placed on the semiconductor chip. Next, a sealing sheet was laminated on the semiconductor element using a press-type vacuum laminator (MVLP-500 manufactured by Meiki Seisakusho Co., Ltd.), and the polyethylene terephthalate (PET) film was peeled off. The pressing conditions were as follows: a hot platen temperature of 80 ° C., a vacuum evacuation time of 20 seconds, a lamination press time of 30 seconds, a pressure of 4 kPa or less, and a pressure of 0.4 MPa. The sealing sheet was repeatedly laminated so that the thickness of the sealing sheet after compression sealing was 350 μm. Next, the semiconductor element mounting surface was compression-sealed to an 8-inch size using a compression sealing facility (WCM-300MS manufactured by Apic Yamada Co., Ltd.). Sealing was performed under the conditions of a sealing temperature of 140 ° C., a sealing pressure of 4.8 MPa, and a sealing time of 10 minutes. Next, it was heated and cured in a clean oven at 150 ° C. for 1 hour.

<Grinding of sealing body>
The sealed body was ground using a grinder. The sealed body was gradually ground until the active surface (surface) of the semiconductor chip was exposed.

<Formation of rewiring layer>
A rewiring layer was formed on the active surface (front surface) side of the semiconductor chip. Specifically, first, a photosensitive material was applied using a spin coater, and exposure and development were performed. Next, the photosensitive material was cured at a predetermined temperature of 200 ° C. in a nitrogen atmosphere (oxygen concentration: 50 ppm or less) for one hour. Next, 100 nm of Ti was vapor-deposited by sputtering, and 300 nm of Cu was continuously vapor-deposited to form a seed layer. Then, a dry film resist (manufactured by Hitachi Chemical Co., Ltd., trade name: Phototec RY-3525) is attached with a roll laminator, and a photo tool on which a pattern is formed is brought into close contact with the film. Exposure was performed using an energy amount of 100 mJ / cm ² . Subsequently, spray development was performed for 90 seconds with a 1% by weight aqueous solution of sodium carbonate at 30 ° C. to open the dry film resist. Next, a 7 μm-thick copper plating was formed on the seed layer by an electrolytic copper plating method. Next, the dry film resist was stripped off with a stripping solution. Next, the seed layer was removed with an etchant. Next, a photosensitive material was applied again by a spin coater, and exposure and development were performed. Next, the photosensitive material was cured at a predetermined temperature of 200 ° C. in a nitrogen atmosphere (oxygen concentration: 50 ppm or less) for one hour.

<Bump mounting>
First, using a commercially available electroless nickel / gold plating solution, plating was performed to a nickel plating thickness of 2 μm and a gold plating thickness of 0.1 μm to form a nickel / gold layer on copper plating. Next, the solder balls were mounted on the nickel / gold layer under a nitrogen atmosphere (oxygen concentration: 100 ppm or less) using a reflow apparatus. As a result, a device formed body which is a set of the semiconductor chip on which the rewiring and the solder bumps were formed and the sealing body was formed.

<Separation (peeling) of support with temporary fixing sheet>
In order to separate the support with the sheet for temporary fixing from the device formed body obtained as described above, a laser output of 10 W, a frequency of 30 MHz, a laser scan speed of 4000 m / s, and a laser scan width of 0 from the light-transmitting support side. Irradiation energy from a YAG laser generating light at a wavelength of 1064 nm was applied under a condition of 0.3 mm. Thereafter, the light-transmitting support was manually peeled off from the light-heat conversion layer of the temporary fixing sheet. Then, in order to peel the temporary fixing sheet from the device formed body, an adhesive tape (AD-80H-30A manufactured by Denki Kagaku Co., Ltd.) is attached to the temporary fixing sheet, and the 180 ° direction (that is, the temporary fixing sheet is used). (Direction perpendicular to the sheet). As a result, the light-to-heat conversion layer and the adhesive layer of the temporary fixing sheet could be simultaneously peeled from the semiconductor chip without damaging the semiconductor chip of the device formed body.

<Individualization>
Finally, a semiconductor device having a package size of 9.6 mm × 9.6 mm was successfully obtained by dicing the sealing body of the device formed body.

  DESCRIPTION OF SYMBOLS 1 ... Light transmissive support, 2 ... Temporary fixing sheet, 2A ... Light-heat conversion layer, 2B ... Adhesive layer, 3 ... Semiconductor chip, 4 ... Sealing body, 5 ... Rewiring, 6 ... Bump, 7 ... Device formation Body, 8: radiant energy, 10: semiconductor device.

Claims (3)

Laminating a temporary fixing sheet containing the resin composition on the light-transmitting support,
Temporarily fixing a semiconductor chip on the temporary fixing sheet,
Forming a sealing body covering the temporarily fixed semiconductor chip,
Grinding the sealing body so that the surface of the semiconductor chip on the side opposite to the light-transmitting support is exposed,
Forming a wiring on the surface of the semiconductor chip exposed from the sealing body,
From the semiconductor chip, a step of peeling the light transmitting support and the temporary fixing sheet,
A method for manufacturing a semiconductor device comprising:
In the step of peeling off the temporary fixing sheet, the resin composition of the temporary fixing sheet is decomposed by irradiating the temporary fixing sheet with radiant energy from the light-transmitting support side. After peeling the support, peeling the temporary fixing sheet from the semiconductor chip and the sealing body ,
As the temporary fixing sheet, a light-to-heat conversion layer that is in contact with the light-transmitting support, and a laminated sheet that is provided on the light-to-heat conversion layer and temporarily fixes the semiconductor chip and has an adhesive layer including an inorganic filler. Use,
A method for manufacturing a semiconductor device.   2. The method according to claim 1, wherein, in the step of peeling off the temporary fixing sheet, the radiant energy is supplied by a YAG laser that generates light having a wavelength of 1064 nm. In the step of laminating a pre-Symbol temporary fixing sheet, the photothermal conversion layer is in contact with the light transmissive support, such that the adhesive layer is located on the opposite side of the light transmissive support, the temporary fixing sheet 3. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is laminated on the light-transmitting support.

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