JP2011165802A - Semiconductor device and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a semiconductor device, which can perform high heat processing on a semiconductor circuit portion regardless of the material of a substrate. <P>SOLUTION: A porous structure layer 4 which is formed of silicone resin and has density of ≤0.7 g/cm<SP>3</SP>is arranged on a resin substrate 2. Preferably, the silicone resin consists of ≥95 mass% of silsesquioxane or siloxane, and the silsesquioxane is methyl silsesquioxane or phenyl silsesquioxane. A semiconductor element layer 3 is installed on the porous structure layer and it is intermittently heated only from the side of the semiconductor element layer by light or electron beams. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor device such as a solar cell, a thin film transistor circuit, and a display (image display device), and a manufacturing method thereof.

  In semiconductor devices such as displays and thin film solar cells, research on flexibility has been actively conducted. Resin films such as PET and polyimide are used for the substrate to provide flexibility, but the semiconductor manufacturing process temperature is room temperature because the heat resistance is lower than that using a normal glass substrate. There is a problem that it is limited to the vicinity. On the other hand, as a semiconductor characteristic, since the characteristic produced by the high temperature process is generally better, it is a great obstacle to flexibility.

  Several means have been proposed as a method for solving this problem. For example, in Patent Document 1 and Patent Document 2, a semiconductor circuit is formed in advance on a glass substrate, and the formed semiconductor circuit is peeled or dissolved from the glass substrate. And a method of transferring to a resin substrate is described. According to this method, although the heat resistance of the resin is not restricted in the semiconductor manufacturing process, a new process of peeling and transfer is necessary, and it is extremely difficult to increase the area and stabilize the quality.

Patent Document 3 proposes a method of forming polycrystalline Si by laminating a SiO ₂ film and an amorphous Si film on a PET film and irradiating the amorphous Si film with an excimer laser. Compared with amorphous Si, crystalline Si has much higher carrier mobility, and there is a possibility that a high-performance semiconductor device can be manufactured. However, since the SiO ₂ film is hard and has a large difference in thermal expansion from the PET film, there is a high possibility that cracking or peeling will occur due to heating by excimer laser irradiation. In addition, the excimer laser is an expensive and unstable device, and there is a problem in mass productivity.

Japanese Patent Laid-Open No. 11-24106 Japanese Patent Laid-Open No. 11-31828 JP-T-2001-508937

  As described above, in order to improve performance in the manufacture of a semiconductor device, it is inevitable to manufacture at a high temperature process exceeding 200 ° C. However, in the manufacture of a conventional semiconductor device, heating of the manufacturing process is limited depending on the material of the substrate. Therefore, the actual situation is that the manufacturing is performed by selecting whether to improve the performance even if a new process is added, or to sacrifice the manufacturing cost and mass productivity to some extent to improve the performance.

  The present invention has been made in view of the above circumstances, and provides a semiconductor device capable of performing high heat treatment on a semiconductor circuit portion regardless of the material of the substrate and a method for manufacturing the same, and in particular, a flexible large-area semiconductor. It is an object of the present invention to provide a substrate structure that can be suitably used in an apparatus and a method for manufacturing the same.

The semiconductor device of the present invention is a semiconductor device composed of a substrate and a semiconductor element, and has a porous structure layer of silicone resin between the substrate and the semiconductor element.
The density of the porous structure layer of the silicone resin is preferably 0.7 g / cm ³ or less.

In the porous structure layer of the silicone resin, 95% by mass or more of the silicone resin is a silicone resin made of silsesquioxane or siloxane, and 20% by mass or more of the silicone resin is silsesquioxane. Is preferred.
The silsesquioxane is preferably methyl silsesquioxane or phenyl silsesquioxane.
More preferably, the substrate is a resin substrate.

The method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device having a porous structure layer of silicone resin between the substrate and the semiconductor element, the porous structure of the silicone resin on the substrate. A body layer is provided, a semiconductor element layer is provided on the porous structure layer, and heating is intermittently performed only from the semiconductor element layer side.
The heating is preferably by light or electron beam.

  The semiconductor device of the present invention has a structure having a porous structure layer of silicone resin between a substrate and a semiconductor element. Since the semiconductor element is provided on the porous structure layer of silicone resin, the semiconductor device is independent of the material of the substrate. It is possible to perform high-temperature heat treatment, and if the semiconductor device, for example, the semiconductor device is a thin film transistor circuit, it is possible to improve the electron mobility, and the semiconductor device has high performance. it can.

  In the method for manufacturing a semiconductor device of the present invention, a porous structure layer of silicone resin is provided on a substrate, a semiconductor element layer is provided on the porous structure layer, and heating is intermittently performed only from the semiconductor element layer side. Therefore, before the heat conduction from the semiconductor element layer side affects the substrate by the porous structure layer of the silicone resin, the semiconductor element layer can be sufficiently heated to improve the performance. Therefore, regardless of the material of the substrate, a high-performance semiconductor device can be manufactured at low cost and with high productivity without performing complicated steps.

1 is a schematic cross-sectional schematic view showing an embodiment of a semiconductor device of the present invention. It is a graph which shows the relationship between the density of a polysilsesquioxane of a porous structure, and thermal conductivity. It is the graph which simulated the change of the heating time and surface temperature at the time of using zinc for the surface. It is the graph which simulated the change of the heating time and temperature distribution in asymmetric heating.

  Hereinafter, a semiconductor device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional schematic view showing an embodiment of a semiconductor device of the present invention. As shown in FIG. 1, the semiconductor device 1 is configured to have a porous structure layer 4 (hereinafter also referred to as a silicone resin layer 4) of a silicone resin between a substrate 2 and a semiconductor element layer 3.

The silicone resin layer 4 used in the present invention is a silicone resin represented by the general formula of (R ¹ R ² R ³ SiO _0.5 ) _W (R ⁴ R ⁵ SiO) _X (R ⁶ SiO _1.5 ) _Y (SiO ₂ ) _Z The ratio of the (R ⁶ SiO _1.5 ) skeleton and the (SiO ₂ ) skeleton is 95% by mass or more of the total mass of the silicone resin, and the ratio of the (R ⁶ SiO _1.5 ) skeleton is (R ⁶ SiO _1.5). ) And 20% by mass or more of the total mass of the skeleton and the (SiO ₂ ) skeleton. In the above general formula, (R ¹ R ² R ³ SiO _0.5 ), (R ⁴ R ⁵ SiO), (R ⁶ SiO _1.5 ), and (SiO ₂ ) are M siloxane, D siloxane, and T siloxane (or silsesquioxide), respectively. Oxan), Q siloxane (or simply siloxane), and a basic skeleton structure, and the silicone resin is a copolymer thereof. Among them, the skeleton other than the siloxane skeleton has an R group that is not a siloxane bond, and thus has a certain degree of flexibility. For this reason, even if a board | substrate is a flexible thing like a resin substrate, for example, the flexibility of a board | substrate is not disturbed. In addition, since the porous structure is used, the substrate can have higher flexibility.

  Here, in the ratio of the basic skeleton represented by W to Z in the above general formula, if the ratio of W (M siloxane) and X (D siloxane) is high, there is a problem in the heat resistance of the silicone resin. Is more preferable. Even when it is unavoidably included in the raw material monomer, it is preferably less than 5 mass% of the total mass of the silicone resin. Y (silsesquioxane) and Z (siloxane) have high heat resistance, and these two components are preferably the main composition. However, since the siloxane skeleton is rigid as described above, if the ratio of Z is too high, flexibility is not obtained when a film-like heat insulating layer is formed on the substrate. Cracks occur when heat history is applied. Therefore, it is more preferable that the silsesquioxane skeleton is contained in an amount of 20% by mass or more and the siloxane skeleton is less than 80% by mass in the silicone resin.

R ^{1 to} R ⁵ are each a hydrocarbyl group having 1 to 10 carbon atoms, a halogen-substituted hydrocarbyl group, an alkenyl group, or hydrogen, and more preferably 1 to 6 carbon atoms. Acyclic hydrocarbyl groups and halogen-substituted hydrocarbyl groups containing at least 3 carbon atoms can have a branched or unbranched structure. Examples of hydrocarbyl groups represented by R include methyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl, 1-methylbutyl, 1- Alkyl groups such as ethylpropyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, hexyl, heptyl, octyl, nonyl and decyl; cycloalkyl groups such as cyclopentyl, cyclohexyl and methylcyclohexyl Preferred examples include aryl groups such as phenyl and naphthyl; alkaryl groups such as tolyl and xylyl; and aralkyl groups such as benzyl and phenethyl.

Examples of halogen-substituted hydrocarbyl groups include 3,3,3-trifluoropropyl, 3-chloropropyl, chlorophenyl, dichlorophenyl, 2,2,2-trifluoroethyl, 2,2,3,3-tetrafluoro. Preferable examples include propyl and 2,2,3,3,4,4,5,5-octafluoropentyl.
The alkenyl group usually has 2 to 10 carbon atoms, or 2 to 6 carbon atoms, and preferably includes vinyl, allyl, butenyl, hexenyl, octenyl and the like.

Among the silsesquioxanes, methylsilsesquioxane (CH ₃ SiO _1.5 ) or phenyl silsesquioxane (C ₆ H ₅ SiO _1.5 ) is more preferable from the viewpoint of heat resistance. In the semiconductor device of the present invention, the silicone resin layer 4 needs to have heat resistance as a heat insulating layer. Among the polysilsesquioxanes, the two polysilsesquioxanes have a high thermal decomposition temperature of 400 ° C. or more. Yes. The methyl silsesquioxane and the phenyl silsesquioxane may not be a single structure, but may be a composite structure of both, or a composite structure of (SiO ₂ ) Q siloxane structure. However, if the ratio of the (SiO ₂ ) Q siloxane structure is high, there is a problem in flexibility as described above. Therefore, the content of the (SiO ₂ ) _n Q siloxane structure is preferably less than 80% by mass.

The density of the porous silicone resin layer is desirably 0.7 g / cm ³ or less, and more preferably 0.1 g / cm ³ or more and 0.7 g / cm ³ or less. When the density of the silicone resin layer is higher than 0.7 g / cm ³ , the thermal conductivity is increased, and depending on the substrate, the semiconductor element layer is easily affected by heating such as annealing of the semiconductor element layer. On the other hand, when the density of the silicone resin is smaller than 0.1 g / cm ³ , the adhesion is deteriorated depending on the material of the substrate, and it is difficult to provide strength suitable for the semiconductor device.

The density of the porous silicone resin layer can be determined, for example, by a nitrogen adsorption measurement method (BET). In the nitrogen adsorption measurement method, the pore diameter and the pore volume V [cm ³ / g] can be measured, and the true density excluding the pores of the porous silicone resin layer is represented by ρ [g / cm ³ ]. Then, the porosity and density of the porous silicone resin layer in the present invention can be calculated from the following formulas (1) and (2).
Porosity: ρV / (ρV + 1) (1)
Density: ρ / (ρV + 1) [g / cm ³ ] (2)
It is known that the true density of polymethylsilsesquioxane is about 1.3 to 1.33 g / cm ³ (Advanced Materials. 19.p1589-p1593. (2007)).

  The porosity of the porous silicone resin layer is preferably 40% or more, more preferably 40% or more and 95% or less. When the substrate is a resin substrate, if the porosity is less than 40%, the semiconductor element layer has a thermal conductivity lower than 0.2 (W / (m · ° C.)), which is a general thermal conductivity of the resin. It becomes easy to be affected by heating such as annealing. On the other hand, if the porosity is higher than 95%, the adhesion may be deteriorated depending on the material of the substrate, and it becomes difficult to provide strength suitable for the semiconductor device.

  If the micropores serving as voids are too large, there may be a problem with the flatness of the film surface, and therefore the pores are preferably 100 nm or less. On the other hand, if it is too small, the density becomes low and it is difficult to obtain a silicone resin layer having a strength suitable for a semiconductor device depending on the material of the substrate. Therefore, the preferable range of the pore diameter is 1 to 100 nm, more preferably 2 to 50 nm. The pore diameter can be measured by the above nitrogen adsorption measurement method. Moreover, you may obtain | require from the image processing of a transmission electron microscope observation image.

  In addition, since nitrogen molecules cannot be adsorbed in the closed pores or pores of several nm or less, such pores cannot be measured by the nitrogen adsorption measurement method described above. However, most of the porous structure silicone resin layer of the present invention is composed of open pores of 5 nm or more, and there is no substantial problem in obtaining the density by the nitrogen adsorption measurement method. For the density / pore volume measurement, Archimedes method, pycnometer, X-ray reflectivity measurement, ellipsometer, dielectric constant measurement, positron lifetime measurement, or the like may be used.

  The thickness of the silicone resin layer depends on the density derived from the porous structure and its thermal conductivity, and also depends on the required annealing temperature and heating method. It functions well as an uninsulated heat insulation layer.

  The porous silicone resin layer of the present invention can obtain a film-like porous silicone resin by a sol-gel reaction with a surfactant interposed, or CVD using a cyclic siloxane monomer as a raw material. In particular, the sol-gel reaction involving a surfactant is a relatively inexpensive and low-temperature manufacturing method because a surfactant is used as a template for forming a porous structure, and a general-purpose resin is used as a support substrate. It is suitable as a manufacturing method for producing a large heat insulating layer structure substrate. The sol-gel reaction mediated by a surfactant can be performed, for example, by the method described in Advanced Materials.19.p1589-p1593. (2007).

  As the surfactant, those having a relatively large molecular weight, for example, those having 10 or more carbon atoms in the alkyl group, block copolymers having a molecular weight of about 10,000, etc. are preferable. By using these, micelles are formed, and a porous structure is formed. Can be a mold. The surfactant is not particularly limited and may be any of cationic, anionic, and nonionic, specifically, alkyltrimethylammonium, alkyltriethyl Ammonium, dialkyldimethylammonium, benzylammonium chloride, bromide, iodide or hydroxide; fatty acid salt, alkyl sulfonate, alkyl phosphate, polyol nonionic surfactant, polyethylene oxide nonionic Surfactant, primary alkylamine, etc. are mentioned. These surfactants can be used alone or in admixture of two or more.

  Metal, ceramics, glass, resin, or the like can be used as the material of the substrate 2 as the support base material, and a resin substrate can be preferably used in order to make a lightweight and flexible semiconductor device by taking advantage of the function of the heat insulating layer. . Examples of the resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), triacetyl cellulose (TAC), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), Resin substrates such as polyarylate (PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), and cyclic polyolefin can be used.

  In particular, even in the case of a substrate having low heat resistance such as a resin substrate such as PET, PEN, and PI, by providing the silicone resin layer 4, only the semiconductor element layer 3 is heated without increasing the temperature of the substrate 2. Is possible. In the case where a flexible substrate is used, it is possible to cope with the flexibility of semiconductor devices such as a display and a thin film solar cell. Since a silicone resin having mesopores of 100 nm or less is transparent, a visible and transparent flexible semiconductor device can be obtained by using an oxide semiconductor such as IGZO and a conductive oxide such as ITO or ZnO.

  Then, the manufacturing method of the semiconductor device of this invention is demonstrated. As described above, the silicone resin layer 4 is provided on the substrate, the semiconductor element layer 3 is provided on the silicone resin layer 4, and heating is intermittently performed only from the semiconductor element layer 3 side. Since the silicone resin layer 4 is a porous structure and has a heat insulating function, when it is heated from the semiconductor element layer 3, a thermal conduction delay phenomenon occurs due to a large thermal time constant based on the low thermal conductivity. Before the temperature of the two parts rises, it is possible to sufficiently heat the semiconductor to improve the performance. The semiconductor element layer 3 requires processing suitable for the semiconductor device to be manufactured, for example, etching and further layer (for example, electrode) deposition, but heating is performed at an appropriate timing in the manufacturing process of the semiconductor device. Is possible. Further, the heating may be aimed not only at improving the performance of the semiconductor, but also for reducing the residual stress that causes warping of the semiconductor device, for example. However, it goes without saying that it is desirable to avoid adding a layer having poor heat resistance before heating.

  For example, when the semiconductor is IGZO (nGaZnO), it is formed on the porous structure layer by a method such as vacuum deposition, sputter deposition, ion plating, chemical vapor deposition (CVD), IGZO is intermittently heated only from the provided IGZO side. In general, the semiconductor physical properties of IGZO formed at room temperature have low carrier mobility and easily vary in characteristics. However, the semiconductor device of the present invention has a porous, low-density silicone resin layer between a substrate and a semiconductor element layer. Therefore, annealing can be performed at 300 to 400 ° C., whereby the mobility of carriers can be improved and the characteristics can be stabilized. For this reason, it can be suitably used for a TFT panel for liquid crystal or organic EL.

  In the case where the semiconductor device is a solar cell using a compound semiconductor as a light absorbing layer, the fine particles are sintered if the fine particles of the compound semiconductor are applied and subjected to rapid heat treatment on the fine particles of the compound semiconductor only from the coated surface. It can be manufactured to function as a light absorption layer.

  For the intermittent heating, for example, light or electron beam irradiation can be used. Even if such a heat treatment is performed, in the method for manufacturing a semiconductor device of the present invention, the porous structure silicone resin functions as a heat insulating layer, causing a delay in heat conduction, so suppressing the temperature rise of the substrate, Heating can be performed.

  Here, intermittent heating means a time to such an extent that the porous silicone resin functions as a heat insulation layer, and the total heating time for the semiconductor exceeds the time for the porous silicone resin to function as a heat insulation layer. In the case, it means heating by dividing the heating time. For example, when the total heating time for the semiconductor layer is 1 second and the time for the porous structure silicone resin to function as a heat insulating layer is 0.1 seconds, the heating for 0.1 seconds is intermittently performed. Repeat 10 times.

The heating means is preferably a light or electron beam method for intermittent heating. The intermittent heating does not need to be at the nanosecond level, and intermittent heating of about millisecond or more is sufficient. When the heating means is light, not only excimer laser but also solid laser such as YAG and semiconductor laser can be used, and not only laser light but also flash lamp such as xenon lamp can be used. The wavelength of light is preferably a wavelength that is an absorption region of the material to be heated.
Hereinafter, the semiconductor device and the manufacturing method thereof according to the present invention will be described in more detail with reference to examples.

Example 1
A transparent solution was obtained by mixing 15 parts of 10 mM acetic acid, 2 parts of Pluronic F-127 (a block copolymer surfactant manufactured by BASF), 1 part of urea and 9 parts of methyltrimethoxysilane. This was put into a semi-sealed Teflon (registered trademark) container and subjected to a gelation reaction at 80 ° C. for 2 days. After washing and removing the wet gel surfactant in boiling water, the solvent was replaced with methanol and fluorine solvent (Novec-7100, manufactured by Sumitomo 3M), then dried and dried with a transparent polymethylsilsesquioxane. Quality structure). The density ρ measured by the Archimedes method was 0.40 g / cm ³ .

(Example 2)
A dry gel composed of translucent polymethylsilsesquioxane was obtained in the same manner as in Example 1 except that Pluronic F-127 was changed to 1.5 parts in Example 1. The density ρ measured by the Archimedes method was 0.57 g / cm ³ .

(Example 3)
Example 1 is the same as Example 1 except that 35 parts of 10 mM acetic acid, 16 parts of tetramethoxysilane, 10 parts of methyltrimethoxysilane, 5.5 parts of Pluronic F-127, and 2.5 parts of urea are mixed. A dry gel made of a copolymer of transparent methylsilsesquioxane and siloxane was obtained by the same procedure. The weight ratio of the siloxane / silceroxyoxane skeleton calculated from the blending ratio is 61/39. The density ρ measured by the Archimedes method was 0.40 g / cm ³ .

(Comparative Example 1)
A dry gel composed of translucent polymethylsilsesquioxane was obtained in the same manner as in Example 1 except that Pluronic F-127 was not used. The density ρ measured by the Archimedes method was 1.18 g / cm ³ .

(Evaluation)
The porosity and density of the samples of Examples 1 to 3 were determined from the pore volume determined from the nitrogen adsorption isotherm of the BET measurement according to the equations (1) and (2) described above. The results are shown in Table 1. The true density of the silicone resin was calculated as 1.3 g / cm ³ . In Examples 1 to 3, a porous silicone resin having mesopores of about 30 nm is obtained. It can also be seen that the density obtained by BET and the density obtained by the Archimedes method are almost the same. In the sample of Comparative Example 1, the BET method pores and their volumes were below the detection limit.

  The samples obtained in Examples 1 to 3 and Comparative Example 1 were polished to a thickness of about 0.3 mm, and the thermal diffusivity α was measured by a laser flash method (TC-9000 manufactured by ULVAC-RIKO). The heat conductivity λ was determined from the value of weight specific heat C measured separately by DSC (Differential Scanning Calorimeter, TA Instruments Model 2920), using the formula of λ = ρ · C · α. The thermal conductivities of Comparative Example 1 were 0.043, 0.059, 0.045, and 0.353 (W / (m · ° C.)), respectively.

  In general, the thermal conductivity of a solid material having voids is expressed by the following formula as Braggemann's formula (where φ is the volume filling rate of the silicone resin, λf is the thermal conductivity of the silicone resin, λc is the thermal conductivity of the porous layer, λm is the thermal conductivity of air in the porous layer), and when the heat conduction component is a spherical body and percolation conduction, the index m is 1/3.

Here, when the void portion is air and the thermal conductivity is 0.024 W / m · ° C. and plotted together with the measurement result of the sample, the relationship between the thermal conductivity and the density is as shown in FIG. In FIG. 2, the plots of Examples 1 and 3 overlap), and it can be seen that the plots almost match Braggemann's formula. If the density is 0.7 g / cm ³ or less, it becomes less than half of 0.2 W / m · ° C. which is the thermal conductivity of general resin, and it is effective as a heat insulating layer even for a resin substrate having low heat resistance. It can be seen that it works.
In order to confirm that the porous structure made of a silicone resin actually functions as a heat insulating layer in heating at the time of manufacturing a semiconductor device, the following experiment was conducted.

(Example 11)
A thickness obtained by preparing a solution in which 10 parts of 3-glycidoxypropyltrimethoxysilane, 10 parts of phenyltriethoxysilane, 0.2 part of aluminum acetylacetonate, 2 parts of hydrochloric acid and 5 parts of water were prepared, and subjected to UV-ozone treatment. A 100 μm PEN film was spin coated. Thereafter, the coating film was dried at 100 ° C., and then kept at 170 ° C. for 1 hour, followed by curing and desolvation treatment to obtain an adhesion layer. When the cross section of the adhesion layer was observed with an SEM, it was about 0.1 μm, and voids and the like were not observed.

  On the PEN film with the adhesion layer, a coating film was formed by the doctor blade method using the solution of Example 1. This was placed in a semi-sealed Teflon (registered trademark) container and subjected to a gelation reaction at 80 ° C. for 2 days in an ammonia atmosphere. The obtained film with a gel film was treated in the same manner as in Example 1 to obtain a dry gel film made of polymethylsilsesquioxane having a thickness of 10 μm.

(Example 12)
A dry gel film made of polymethylsilsesquioxane having a thickness of 10 μm was obtained in the same procedure as in Example 11 except that the solution of Example 2 was used after forming an adhesion layer similar to that in Example 11.

(Example 13)
A dry gel film made of a copolymer of methylsilsesquioxane and siloxane having a thickness of 10 μm in the same procedure as in Example 11 except that the solution of Example 3 was used after the adhesion layer similar to that in Example 11 was formed. Got.

(Comparative Example 11)
A dry gel film made of polymethylsilsesquioxane having a thickness of 10 μm was obtained in the same procedure as in Example 11 except that the solution of Comparative Example 1 was used after forming an adhesion layer similar to that in Example 11.

(Evaluation)
The density was calculated | required similarly to Examples 1-3 from the pore volume calculated | required for the sample of Examples 11-13 from the nitrogen adsorption isotherm of BET measurement. The results are shown in Table 2. Since the membrane portion has a small volume, density measurement is impossible with the Archimedes method, but the dry gel membranes obtained from the same compounded liquid have substantially the same average pore diameter and density, so that Examples 1 to Similar to 3, a porous silicone resin film having mesopores of about 30 nm is obtained. In the sample of Comparative Example 11, as in Comparative Example 1, the BET method pores and their volumes were below the detection limit.

Zn was deposited by 0.5 μm on the dry gel film side of the samples obtained in Examples 11 to 13 and Comparative Example 11, and a semiconductor laser with a wavelength of 808 nm was irradiated once for 30 msec with an irradiation surface intensity of 100 W / cm ² . Separately, 30 msec irradiation was performed 10 times at intervals of 0.5 sec. When the Zn surface of the irradiated sample was observed with an optical microscope, the surface was rough for both the 1-time irradiation and the 10-time irradiation in the example, and the melting of Zn was observed. The surface was the same as unirradiated, and no melting of Zn was observed. Since the melting point of Zn is 419 ° C., in the examples, it can be determined that the dry gel film made of a porous silicone resin functions effectively as a heat insulating layer. In both samples, no abnormality was observed on the PEN surface, and no deformation such as warping was observed.

In order to estimate the sample temperature change during heating, a one-dimensional heat conduction analysis in the film thickness direction was performed by a thermal network method. Literature values were used for the thermophysical values (density, volume specific heat, thermal conductivity) of Zn and PEN, and the measured values obtained in Example 1 and Comparative Example 1 were used for the dry gel film. Heating was performed at 100 W / cm ² on the Zn surface for 30 milliseconds, and heat radiation was performed at an emissivity of the Zn surface of 0.3 and an emissivity of the PEN surface of 0.9. Zn that simulates the semiconductor circuit layer 3, the heat insulation layer 4, and the PEN of the substrate 2 are divided into thermal circuit elements in the thickness direction, and the heat conduction and transient temperature of each thermal circuit element are calculated in increments of 5 milliseconds. FIG. 4 shows the value calculated in steps of 0.5 milliseconds. (The Examples and Comparative Examples in FIGS. 3 and 4 are Example 11 and Comparative Example 11).

  In FIG. 3, although the Zn surface temperature is about 440 ° C. at the maximum in the example, it remains at about 260 ° C. in the comparative example. The PEN surface temperature is not significantly different between the examples and the comparative examples, and the temperature rises slowly compared to the Zn surface temperature, and reaches a maximum of about 140 ° C., but the temperature of the entire system is approximately equal to about 0.1 second. It turns out that radiation cooling is performed. From this result, since the thermal conductivity of the porous structure layer of the silicone resin is low in the sample of the example, it is possible to raise only the Zn surface temperature, and it is possible to raise the temperature to the melting temperature of Zn. However, since it is not a porous structure layer in the comparative example, the thermal conductivity is high, and it is judged that the melting temperature of Zn has not been reached. In the comparative example, in order to make the Zn surface higher than the melting temperature, for example, it is necessary to lengthen the heating time. In this case, the PEN surface temperature is also raised with a time delay of about 30 milliseconds. It is estimated that the temperature will also be higher than the heat resistance temperature.

  FIG. 4 shows the temperature distribution and its change with time during asymmetric heating. In the graph, A is the Zn surface, B is the center of the heat insulating layer made of silicone resin, C is the interface between the heat insulating layer and PEN, D is the center of the PEN layer, E is the PEN surface, and the subscript 1 is an example. 2 shows a comparative example.

As is apparent from the graph, the temperature distribution of the PEN part and its change (D ₁ , D ₂ , E ₁ , E ₂ ) during heating and in the process where the temperature of the entire system becomes almost uniform are shown in the examples and comparisons. There is no big difference between the examples. On the other hand, although the temperature distribution of the Zn surface and the heat insulating layer is large in the examples (A ₁ , B ₁ ) and small in the comparative examples (A ₂ , B ₂ ), the Zn surface temperature (A ₁ ) in the examples is therefore It is higher than the Zn surface temperature (A ₂ ) in the comparative example. From this result, it can be seen that thermal annealing at 400 ° C. or higher is possible in the examples when the porous structure layer of the silicone resin functions as a heat insulating layer.

Further, from the same heat conduction simulation, when the thermal conductivity of the heat insulation layer is 0.1 W / (m · ° C.) or less, if the film thickness is 1 μm or more, the heat insulation layer and the PEN interface temperature (C ₁ ) and Zn As for the surface temperature (A ₁ ), a result of causing a temperature difference of 50 ° C. or more by asymmetric heating was obtained. From the relationship between the thermal conductivity and density of Examples 1 and 2 and the comparative example, if the silicone resin has a density of 0.7 g / cm ³ or less, it becomes 0.1 W / (m · ° C.) or less. However, thermal annealing higher by 50 ° C. than the heat resistant temperature is possible.

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Board | substrate 3 Semiconductor element layer 4 Silicone resin porous structure layer

Claims (7)

  A semiconductor device comprising a substrate and a semiconductor element, comprising a porous structure layer of silicone resin between the substrate and the semiconductor element. The semiconductor device according to claim 1, wherein the density of the porous structure layer of the silicone resin is 0.7 g / cm ³ or less.   In the porous structure layer of the silicone resin, 95% by mass or more of the silicone resin is a silicone resin made of silsesquioxane or siloxane, and 20% by mass or more of the silicone resin is silsesquioxane. The semiconductor device according to claim 1 or 2.   4. The semiconductor device according to claim 3, wherein the silsesquioxane is methyl silsesquioxane or phenyl silsesquioxane.   The semiconductor device according to claim 1, wherein the substrate is a resin substrate.   The method for manufacturing a semiconductor device according to claim 1, wherein a porous structure layer of the silicone resin is provided on the substrate, and a semiconductor element layer is provided on the porous structure layer, A method of manufacturing a semiconductor device, comprising heating intermittently only from the semiconductor element layer side.   The method of manufacturing a semiconductor device according to claim 6, wherein the heating is performed by light or an electron beam.

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