JP2009290164A - Photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion device which is excellent in reinforcement effect handling nature of a wafer in which peeling between a film and the wafer in high temperature and high humidity is not generated. <P>SOLUTION: The photoelectric conversion device is constituted by laminating a polymer film whose glass transfer temperature is ≥70°C at least on one side of a semiconductor wafer in which a photoelectric conversion element is formed via a thermoplastic resin layer, wherein the thermoplastic resin layer contains fluorine resin and liquid crystal polymer of thermotropic type, a content rate of the fluorine resin in the thermoplastic resin layer is 20-80 mass% and the content rate of the liquid crystal polymer of the thermotropic type is 20-80 mass%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device in which a photoelectric conversion element is formed on a semiconductor wafer, and more particularly to a thin photoelectric conversion device (preferably having a wafer thickness of 500 μm or less).

In recent years, photoelectric energy conversion devices such as solar cells have been made thinner, smaller and lighter, and semiconductor wafers for such photoelectric conversion devices have been made thinner due to cost reduction requirements.
A semiconductor wafer is generally obtained by cutting a single crystal or polycrystal ingot into a thin plate with a wire saw or the like, and grinding and polishing the surface. Although it has become possible to obtain very thin wafers due to recent technological innovations, semiconductor wafers are generally brittle and very susceptible to cracking due to bending loads. A technique for handling a semiconductor wafer by sticking an adhesive tape to the wafer so that the wafer is prevented from cracking during handling and processing and at the same time facilitating handling is widely known (for example, Patent Documents 1 to 3). ). The pressure-sensitive adhesive tape used in such a process is called a carrier tape, a dicing tape, or the like, which is attached only during the processing and is peeled off before moving to the mounting process.

  On the other hand, a die attach film used for the purpose of fixing a semiconductor element to a support such as a substrate is known (Patent Document 4). These are made of a heat-resistant material, inserted between the back surface of the semiconductor chip and the substrate, used for the purpose of bonding the two, and do not reinforce the semiconductor element itself.

On the other hand, it is meaningful to attach a film in the sense of reinforcement not only during the processing process but also at the stage of the photoelectric conversion device that is diced and finally becomes a product, simplifying the process and reducing costs. Therefore, a die attach film that can be used in both the wafer processing step and the semiconductor element bonding step has been disclosed (for example, Patent Documents 5 to 7).
However, in the conventional technology, when the process film is left in the mounting process, long-term durability is insufficient, and resistance to strong thermal stress or repeated thermal stress in the mounting process is insufficient. It was not satisfactory enough to meet the demand for ensuring the practical durability of the converter.
JP 2006-156638 A JP 2005-290091 A JP 05-129431 A JP 2004-186296 A JP 2002-294177 A JP 2003-109916 A JP 2003-129025 A

  INDUSTRIAL APPLICABILITY The present invention can improve long-term durability when a process film is left in a mounting process, and is suitable for a photoelectric conversion device that can meet various wide requirements (heat resistance, heat and humidity resistance) in a mounting process, particularly a solar cell. A photoelectric conversion device is to be provided.

That is, this invention is based on the following structure.
1. A laminated body in which a polymer film having a glass transition temperature of 70 ° C. or higher is laminated on at least one surface of a semiconductor wafer on which a photoelectric conversion element is formed via a thermoplastic resin layer, and the thermoplastic resin layer is a fluororesin And a thermotropic liquid crystal polymer, the content of the fluororesin in the thermoplastic resin layer is 20 to 80% by mass, and the content of the thermotropic liquid crystal polymer is 20 to 80% by mass. A photoelectric conversion device characterized by the above.
2. The above-mentioned 1. wherein the thermotropic liquid crystal polymer is a wholly aromatic polyester. Photoelectric conversion device.
3. 1. The fluororesin is a thermoplastic fluororesin obtained by copolymerization using a fluorine-containing ethylenic monomer having at least a hydroxyl group and an ethylenic monomer having no hydroxyl group. Or 2. Photoelectric conversion device.
4). Any one of the above 1. to 3. wherein the ethylenic monomer having no hydroxyl group of the fluororesin is at least one selected from tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ether. The photoelectric conversion device described in 1.
5. 1. The polymer film as described above, which is a polyimide film containing as a main component a non-thermoplastic polyimide obtained by polycondensation of aromatic tetracarboxylic acids and aromatic diamines. ~ 4. A photoelectric conversion device according to any one of the above.
6). The polymer film is mainly composed of polyimide benzoxazole obtained by polycondensation of aromatic tetracarboxylic acids and aromatic diamines having a benzoxazole structure, and has a linear expansion coefficient of −10 to 10 ppm / ° C. . ~ 5. The photoelectric conversion apparatus in any one of.
7). 1. The semiconductor wafer is monocrystalline silicon. ~ 6. The photoelectric conversion apparatus in any one of.
8). 1. The semiconductor wafer is polycrystalline silicon. ~ 6. The photoelectric conversion apparatus in any one of.
9. 1. The semiconductor wafer is a compound semiconductor. ~ 6. The photoelectric conversion apparatus in any one of.

In the photoelectric conversion device of the present invention, the thermoplastic resin layer includes a fluororesin and a thermotropic liquid crystal polymer, so that the fluororesin and the thermotropic liquid crystal polymer take a sea-island type phase separation structure, The component fluororesin exhibits an excellent effect of combining moldability, adhesiveness, and heat resistance due to the adhesive effect and the reinforcing effect of the fluororesin by the thermotropic liquid crystal polymer of the island component.
In the present invention, a film having a high glass transition temperature and excellent heat resistance equivalent to that of a semiconductor wafer is attached to the wafer via the thermoplastic resin layer having the above-described characteristics in the present invention. The wafer can be protected from vibrations and shocks, the handling can be improved, the wafer is cut into photoelectric conversion element shapes, and there is no problem when divided, and the element itself is lined during the mounting process and actual use. Effects such as reinforcement can be obtained.

The polymer film used in the present invention is not particularly limited as long as it has a glass transition temperature of 70 ° C. or higher. For example, a polyimide film, polysulfone film, polyamideimide film, wholly aromatic polyamide film, all An aromatic polyester film and the like can be mentioned. Among polyimide films, a polyimide film mainly composed of non-thermoplastic polyimide can be preferably applied.
Polyimide films mainly composed of non-thermoplastic polyimides include, for example, aromatic tetracarboxylic acids (collectively referred to as anhydrides, acids, and amide bond derivatives, hereinafter) and aromatic diamines (amines and amides). It is a polyimide film obtained by a method in which a polyamic acid solution obtained by reacting a binding derivative is generically referred to as a group, hereinafter the same) is cast, dried and heat-treated (imidized) to form a film. Here, the non-thermoplastic polyimide is (1) a high concentration of imide units in repeating units in the polymer chain, and (2) a rigid molecular chain in which planar aromatic imide groups are arranged linearly or planarly. Means that the molecule does not show a clear melting point and glass transition temperature because the molecules are in a strong association state. Hereinafter, although this polyimide film is explained in full detail, it is not limited to this.
Although the said polyimide film is not specifically limited, The combination of the following aromatic diamine and aromatic tetracarboxylic acid (anhydride) is mentioned as a preferable example.
A. Combination with aromatic tetracarboxylic acid having pyromellitic acid residue and aromatic diamine having benzoxazole structure.
B. A combination of an aromatic diamine having a phenylenediamine skeleton and an aromatic tetracarboxylic acid having a biphenyltetracarboxylic acid skeleton.
C. A combination of an aromatic diamine having a diphenyl ether skeleton and an aromatic tetracarboxylic acid having a pyromellitic acid residue.
In particular, A. A polyimide film having an aromatic diamine residue having a benzoxazole structure is preferred.

  The molecular structure of the aromatic diamines having the benzoxazole structure is not particularly limited, and specific examples include the following. These diamines are preferably 70 mol% or more, more preferably 80 mol% or more of the total diamine.

  Among these, from the viewpoint of easy synthesis, each isomer of amino (aminophenyl) benzoxazole is preferable, and 5-amino-2- (p-aminophenyl) benzoxazole is more preferable. Here, “each isomer” refers to each isomer in which two amino groups of amino (aminophenyl) benzoxazole are determined according to the coordination position (eg, the above “formula 1” to “formula 4”). Each compound described in the above. These diamines may be used alone or in combination of two or more.

  Furthermore, as long as it is 30 mol% or less of the total diamine, one or more of the diamines exemplified below may be used in combination. Examples of such diamines include 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, and bis [4- (3-aminophenoxy) phenyl]. Sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3′-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-dia Nodiphenyl sulfide, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4,4′-diaminodiphenyl sulfoxide, 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4 , 4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4, 4′-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-amino) Phenoxy) phenyl] ethane, 1,1-bis [4- 4-aminophenoxy) phenyl] propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, , 4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl ] Butane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-a Minophenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2- Bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexa Fluoropropane, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4 -Aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-amino) Enoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1, 3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] Benzene, 4,4′-bis [(3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) ) Phenyl] propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenoxy) phenyl -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1 , 2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-Amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} fe Sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethyl Benzyl] benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluoro) Phenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4 -Amino-6-cyanophenoxy) -α, α-dimethylbenzyl] benzene, 3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-dipheno Cibenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino- 4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4′-diamino-4,5′-dibiphenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 4,4′-diamino-5-biphenoxybenzophenone, 3,4′-diamino-4 -Biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) Benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-bi) Phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- ( 4-amino-α, α-dimethylbenzyl) phenoxy] benzonitrile and some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine are halogen atoms, An alkyl group having 1 to 3 carbon atoms, an alkoxyl group, a cyano group, or an alkyl group or an alkoxyl group having 1 to 3 carbon atoms in which some or all of the hydrogen atoms of the alkyl group or alkoxyl group are substituted with halogen atoms. Examples thereof include substituted aromatic diamines.

  The molecular structure of the aromatic tetracarboxylic acid anhydrides is not particularly limited, and specific examples include the following. These acid anhydrides are preferably 70 mol% or more, more preferably 80 mol% or more of the total acid anhydride.

  These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

  Furthermore, as long as it is 30 mol% or less of the total tetracarboxylic dianhydrides, one or more of the non-aromatic tetracarboxylic dianhydrides exemplified below may be used in combination. Examples of such tetracarboxylic acid anhydrides include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, and cyclobutanetetracarboxylic acid. Acid dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclohex-1-ene-2,3 5,6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3 -(1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride 1-ethylcyclohexane -(1,2), 3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane- 1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane-1 -(2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ', 4'-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane -2,3,5,6-tetracarboxylic dianhydride, Cyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic acid A dianhydride etc. are mentioned.

  The solvent used when reacting (polymerizing) the aromatic tetracarboxylic acid and the aromatic diamine to obtain a polyamic acid is particularly suitable as long as it can dissolve both the raw material monomer and the produced polyamic acid. Although not limited, polar organic solvents are preferred, such as N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl Examples thereof include sulfoxide, hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and halogenated phenols. These solvents can be used alone or in combination. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material. As a specific amount used, the mass of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by mass, The amount is preferably 10 to 30% by mass.

  Conventionally known conditions may be applied for the polymerization reaction for obtaining the polyamic acid (hereinafter also simply referred to as “polymerization reaction”). As a specific example, in a temperature range of 0 to 80 ° C., 10 Stirring and / or mixing continuously for 30 minutes. If necessary, the polymerization reaction may be divided or the temperature may be increased or decreased. In this case, the order of adding both monomers is not particularly limited, but it is preferable to add aromatic tetracarboxylic anhydrides to the solution of aromatic diamines. The viscosity of the polyamic acid solution obtained by the polymerization reaction is measured with a Brookfield viscometer (25 ° C.), and is preferably 10 to 2000 Pa · s, more preferably 100 to 1000 Pa · s, from the viewpoint of the stability of liquid feeding. It is.

Vacuum defoaming during the polymerization reaction is effective for producing a good quality polyamic acid solution. Moreover, you may perform superposition | polymerization by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction. Examples of the end capping agent include compounds having a carbon-carbon double bond such as maleic anhydride. The amount of maleic anhydride used is preferably 0.001 to 1.0 mol per mol of aromatic diamine.
In order to form a polyimide film from the polyamic acid solution obtained by the polymerization reaction, a green film (a self-supporting precursor film is obtained by applying the polyamic acid solution on a support and drying, then, Examples of the method of imidization reaction by subjecting the green film to heat treatment include, but are not limited to, application of the polyamic acid solution to the support, including casting from a slit-attached base and extrusion by an extruder. A conventionally known solution coating means can be appropriately used.

  The conditions for drying the polyamic acid coated on the support to obtain a green sheet are not particularly limited, and examples include a temperature of 70 to 150 ° C. and a drying time of 5 to 180 minutes. A conventionally known drying apparatus that satisfies such conditions can be applied, and examples thereof include hot air, hot nitrogen, far infrared rays, and high frequency induction heating. Next, in order to obtain a target polyimide film from the obtained green sheet, an imidization reaction is performed. As a specific method thereof, a conventionally known imidization reaction can be appropriately used. For example, there may be mentioned a method (so-called thermal ring closure method) in which an imidization reaction proceeds by subjecting to a heat treatment after performing a stretching treatment as necessary using a polyamic acid solution not containing a ring closure catalyst or a dehydrating agent. The heating temperature in this case is exemplified by 100 to 500 ° C., and from the viewpoint of film physical properties, more preferably, a two-stage heat treatment in which treatment is performed at 350 to 500 ° C. for 3 to 20 minutes after treatment at 150 to 250 ° C. for 3 to 20 minutes. Is mentioned.

Another example of the imidization reaction is a chemical ring closure method in which a polyamic acid solution contains a ring closure catalyst and a dehydrating agent, and the imidization reaction is performed by the action of the ring closing catalyst and the dehydrating agent. In this method, after the polyamic acid solution is applied to the support, the imidization reaction is partially advanced to form a film having self-supporting property, and then imidization can be performed completely by heating. In this case, the condition for partially proceeding with the imidization reaction is preferably a heat treatment for 3 to 20 minutes at 100 to 200 ° C., and the condition for allowing the imidization reaction to be completely performed is preferably 200 to 400 ° C. For 3 to 20 minutes.
The thickness of the polyimide film is not particularly limited, but is preferably 1 to 100 μm, more preferably 1 to 50 μm, and still more preferably 1 to 25 μm for the purpose of reducing the weight of electronic components. is there. Further, the thickness unevenness of these films is also preferably 20% or less, and the use of these films can greatly contribute to lightness, smallness and thinness of electronic components.
It is preferable for the above-described reason that the polyimide film has a linear expansion coefficient (CTE) of −10 to 10 ppm / ° C. for the reason described above, more preferably −5 to 10 ppm / ° C., and still more preferably, -5 to 5 ppm / ° C.

The fluororesin used in the thermoplastic resin layer of the present invention is preferably thermoplastic, more preferably a thermoplastic fluororesin having a hydroxyl group, specifically a fluorine-containing ethylenic monomer having a hydroxyl group and What was manufactured by copolymerizing with the fluorine-containing ethylenic monomer which does not have a hydroxyl group can be illustrated.
As the fluorine-containing ethylenic monomer having a hydroxyl group,
^{_{CX 2 = CX 1 -R f -CH}} 2 OH
Can be mentioned. In the formula, X and X ¹ are the same or different, both are hydrogen atoms or fluorine atoms, R _f is a divalent fluorine-containing alkylene group having 1 to 40 carbon atoms, fluorine-containing oxyalkylene group having 1 to 40 carbon atoms, carbon number The fluorine-containing alkylene group containing a 1-40 ether bond or the fluorine-containing oxyalkylene group containing a C1-C40 ether bond is represented.

As the fluorine-containing ethylenic monomer having a hydroxyl group, more specifically,
^{_{CF 2 = CF-R f 1}} -CH 2 OH
Can be mentioned. In the formula, R _f ¹ is a divalent fluorine-containing alkylene group having 1 to 40 carbon atoms or —OR _f ² , where R _f ² is a divalent fluorine-containing alkylene group having 1 to 40 carbon atoms or 1 to 1 carbon atoms. It is a divalent fluorine-containing alkylene group containing 40 ether bonds.
Also,
^{_{CF 2 = CFCF 2 -OR f 3}} -CH 2 OH
Can be mentioned. Wherein, -R _f ³ represents a divalent fluorine-containing alkylene group containing an ether bond of the divalent fluorine-containing alkylene group or 1 to 39 carbon atoms to 39 carbon atoms.
Also,
^{_{CH 2 = CFCF 2 -R f 4}} -CH 2 OH
Can be mentioned. Wherein, -R _f ⁴ is a divalent fluorine-containing alkylene group or -OR _f ⁵ (R _f ⁵ is a divalent fluorine-containing alkylene group or from 1 to the number of carbon atoms of 1 to 39 carbon atoms, of 1 to 39 carbon atoms A divalent fluorine-containing alkylene group containing 39 ether bonds).
Also,
^{_{CH 2 = CH-R f 6}} -CH 2 OH
Can be mentioned. Wherein, R _f ⁶ is a divalent fluorine-containing alkylene group having 1 to 40 carbon atoms.
On the other hand, examples of the fluorine-containing monomer not containing a hydroxyl group include tetrafluoroethylene, perfluoroalkyl vinyl ether, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, and the like, preferably tetrafluoroethylene and A copolymer of perfluoroalkyl vinyl ether and a copolymer of tetrafluoroethylene and hexafluoropropylene.

  The mass ratio of the fluororesin in the thermoplastic resin layer in the present invention is 20 to 80% by mass, preferably 30 to 70% by mass, and more preferably 40 to 60% by mass. When the mass ratio of the fluororesin is less than 20% by mass, it is not preferable for reasons such as difficulty in melt molding and a decrease in adhesiveness. On the other hand, if the mass ratio of the fluororesin exceeds 80% by mass, the reinforcing effect by the thermotropic liquid crystal polymer is not sufficient and the heat resistance is inferior.

Examples of the thermotropic liquid crystal polymer used in the thermoplastic resin layer of the present invention include a liquid crystal polyester resin, a liquid crystal polyamide resin, and a liquid crystal polyester amide resin, and a liquid crystal polyester resin is particularly preferable. Here, the thermotropic liquid crystal polymer is a liquid crystal (dissolved in the three-dimensional position, although some order is maintained in the particle direction in the intermediate state between the crystal and the liquid. It means a polymer that becomes a state. The liquid crystal polyester resin may be a polyester resin having a mesogen group (group having liquid crystal forming ability) such as a p-substituted aromatic ring, a linear biphenyl group, and a substituted naphthyl group as a structural unit. Specifically, p-hydroxybenzoic acid monomer, p-hydroxybenzoic acid and diol (aromatic diol such as dihydroxybiphenyl, C _2-6 alkanediol such as ethylene glycol), aromatic dicarboxylic acid ( Examples thereof include a copolymer with at least one monomer selected from terephthalic acid and the like and aromatic hydroxycarboxylic acid (such as oxynaphthoic acid). More specifically, poly p-hydroxybenzoic acid, a copolymer of p-hydroxybenzoic acid and 4,4′-dihydroxybiphenyl, p-hydroxybenzoic acid, 4,4′-dihydroxybiphenyl and terephthalic acid Examples thereof include a copolymer, a copolymer of p-hydroxybenzoic acid units and ethylene terephthalate units, and a copolymer of p-hydroxybenzoic acid and 2-oxy-6-naphthoic acid. Thermotropic liquid crystal polymers have high mechanical properties because they maintain some order in the particle direction due to heat and pressure, but can take a three-dimensional positional order. Nevertheless, it has excellent melt fluidity.

  The mass ratio of the thermotropic liquid crystal polymer in the thermoplastic resin layer in the present invention is 20 to 80% by mass, preferably 30 to 70% by mass, and more preferably 40 to 60% by mass. When the mass ratio of the thermotropic liquid crystal polymer exceeds 80% by mass, it is not preferable for reasons such as difficulty in melt molding and a decrease in adhesiveness. Further, if the mass ratio of the thermotropic liquid crystal polymer is less than 20% by mass, the reinforcing effect is not sufficient and the heat resistance is inferior.

The formulation of the thermotropic liquid crystal polymer fluororesin can melt the fluororesin and mix the liquid crystal polymer, and is not particularly limited, but a predetermined amount of liquid crystal is added to the fluororesin pellets and powder. A method of mixing polymers and mixing them using a twin-screw or single-screw extruder, or a method of preparing a high-concentration filler masterbatch in advance and mixing them during molding can be used.
For the production of the thermoplastic resin layer in the present invention, a film forming method used for the production of a synthetic resin film can be applied and utilized. For example, it can be produced by a T-die molding method, an inflation molding method, an inside mandrel method, a vacuum foamer molding method, or the like.

In the present invention, the thermoplastic resin layer contains a fluororesin and a thermotropic liquid crystal polymer, so that the fluororesin and the thermotropic liquid crystal polymer have a sea-island type phase separation structure, and a sea component fluororesin. Contributes to adhesiveness, and the thermotropic liquid crystal polymer of the island component has a mechanism that reinforces the fluororesin, so that it exhibits an excellent effect that combines moldability, adhesiveness, and heat resistance.
In the thermoplastic resin layer of the present invention, other thermoplastic resins, thermosetting resins, dispersants, stabilizers, in addition to the fluororesin and thermotropic liquid crystal polymer, within a range not inhibiting the effects of the present invention. Etc. can be contained.

The semiconductor wafer used in the present invention is a single crystal composed of a single element such as diamond, silicon, germanium, polycrystal, single crystal of group IV such as silicon carbide, polycrystal, gallium arsenide, gallium nitride, gallium phosphide, III-V group compound semiconductors such as indium phosphide, II-VI group compound semiconductors such as cadmium telluride and zinc selenide, single crystals, polycrystals, aluminum gallium arsenide, aluminum, gallium, indium phosphide, copper indium selenium, It refers to a single crystal of a multi-component compound semiconductor such as copper indium gallium selenium, or a material cut from a polycrystalline ingot into a thin plate shape. Among these, it is preferable that the semiconductor wafer is single crystal silicon, polycrystalline silicon, or a compound semiconductor.
Photoelectric conversion elements are formed on the surfaces of these wafers through a so-called semiconductor process.
In the present invention, the thickness of the wafer is preferably 800 μm or less, more preferably 450 μm or less, still more preferably 250 μm. Even more preferably 150 μm or less. When the wafer thickness is thicker than this, the reinforcing effect by the film attachment is not recognized significantly. In the present invention, the lower limit of the wafer thickness is 8 μm or more, preferably 15 μm or more, more preferably 25 μm or more, and still more preferably 45 μm or more. If the lower limit is less than this range, it becomes difficult to handle the film until it is pasted, and it becomes difficult to obtain a predetermined effect.

In the present invention, the combination of the photoelectric conversion element and the polymer film is attached such that the photoelectric conversion element is formed on at least one side of the wafer and the film is attached on at least one side. Usually, a mode in which a photoelectric conversion element is attached to one side of a wafer and a polymer film is attached to the opposite side via a thermoplastic resin layer is not particularly limited. In some cases, it may be more useful to attach a polymer film to the surface on which the photoelectric conversion element is formed.
The photoelectric conversion elements may be formed on both sides of the wafer. Also in this case, the surface on which the polymer film is attached may be one side or both sides. Such photoelectric conversion elements are electrically connected by a method such as ordinary wire bonding, bump bonding, and automatic tape bonding. Also, the front and back of the wafer can be connected by a through electrode.

  In the present invention, the timing for attaching the polymer film to the wafer is not particularly limited. In the case of a configuration in which a photoelectric conversion element is pasted on one side and a polymer film is pasted on the opposite side, it is preferable to facilitate handling by sticking before entering the wafer processing process or at a relatively early stage of the process. . A general laminator or press may be used for pasting. In order to attach the wafer so as not to damage it, it is necessary to pay close attention to the selection of a cushioning agent.

  The photoelectric conversion element in the present invention mainly refers to an element that performs light-to-electrical conversion, such as a solar cell or an optical sensor. Also included in the category are electrical-to-light conversion elements such as light emitting diodes and semiconductor lasers. These manufacturing processes are based on publicly known methods.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited by a following example. In addition, the evaluation method of the physical property in the following examples is as follows.
1. Reduced viscosity of polyamic acid (ηsp / C)
A solution dissolved in N-methyl-2-pyrrolidone (or N, N-dimethylacetamide) so that the polymer concentration was 0.2 g / dl was measured at 30 ° C. with an Ubbelohde type viscosity tube.

2. The thickness of the polyimide film The polyimide film to be measured was measured using a micrometer (Minetron 1245D, manufactured by Fine Reef).

3. Thickness unevenness of polyimide film About the polyimide film to be measured, in the width direction (TD), measure the full width at intervals of 1 cm in the width direction, and calculate the average thickness, maximum thickness, and minimum thickness between them, and use the following formula Calculated. Moreover, about the longitudinal direction (MD), it measured for 5 m by 5 cm space | interval of the longitudinal direction, the average thickness in the meantime, the maximum thickness, and the minimum thickness were taken out, and it calculated using the following Formula.
Thickness unevenness (%) = ((maximum thickness−minimum thickness) / average thickness) × 100

4). Tensile modulus of elasticity, tensile strength at break, and elongation at break For polyimide films to be measured, the tensile fracture test is performed under the following conditions, and the tensile modulus, tensile strength at break, and elongation at break are measured in the MD direction. did.
Device name: Autograph made by Shimadzu Corporation
Sample length: 100mm
Sample width: 10mm
Pulling speed: 50mm / min
Distance between chucks: 40 mm

5. Linear expansion coefficient (CTE) of polyimide film
For the polyimide film to be measured, the stretch rate in the MD direction and the TD direction is measured under the following conditions, and the stretch rate / temperature at intervals of 90 to 100 ° C., 100 to 110 ° C.,. Measurement was performed up to 400 ° C., and an average value of all measured values from 100 ° C. to 350 ° C. was calculated as CTE (average value).
Device name: TMA4000S manufactured by MAC Science
Sample length: 10mm
Sample width: 2mm
Temperature rise start temperature: 25 ° C
Temperature rise end temperature: 400 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Argon

6). Melting | fusing point of thermoplastic resin About the thermoplastic resin of a measuring object, differential scanning calorimetry (DSC) was performed on the following conditions, and melting | fusing point (Tm) was calculated | required based on JISK7121.
Device name: DSC3100S manufactured by MAC Science
Bread: Aluminum bread (non-airtight type)
Sample mass: 4mg
Temperature rising start temperature: 30 ° C
Temperature rise end temperature: 400 ° C
Temperature increase rate: 20 ° C / min
Atmosphere: Argon

7). Peel strength The peel strength between the polyimide film and the wafer was determined by conducting a 180 degree peel test under the following conditions.
Device name: Autograph AG-IS, manufactured by Shimadzu Corporation
Sample length: 100mm
Sample width: 10mm
Measurement temperature: 25 ° C
Peeling speed: 50mm / min
Atmosphere: Atmosphere

<< Evaluation of Substrate >> Moisture and Heat Resistance Each film-reinforced wafer made of polyimide film, thermoplastic resin, and wafer is placed in a stainless steel mesh basket and 121 ° C. × 2 using a PCT apparatus (PC242-III, manufactured by Hirayama Seisakusho). A pressure heat treatment was performed for 96 hours in a saturated vapor pressure of atmospheric pressure, and the peel strength after the test was evaluated. In addition, in the appearance inspection after the test, the case where peeling, blistering, and discoloration were not observed was indicated as “◯”, the case where slight peeling, blistering, and discoloration were observed as Δ, and the case where peeling, blistering, and discoloration were observed as “X”.

<< Evaluation of Substrate >> Heat Resistance Each film-reinforced wafer comprising a polyimide film, a thermoplastic resin, and a wafer was subjected to a heat treatment at 240 ° C. for 3 minutes using a reflow soldering apparatus, and the peel strength after the test was evaluated. In addition, in the appearance inspection after the test, the case where peeling, blistering, and discoloration were not observed was indicated as “◯”, the case where slight peeling, blistering, and discoloration were observed as Δ, and the case where peeling, blistering, and discoloration were observed as “X”.

<< Evaluation of Substrate >> Handling property A film-reinforced wafer is divided into single wafers. A single crystal silicon wafer is put into a carrier for 100 mm wafer, a GaAs wafer is put into a carrier for 50 mm wafer, and continuous vibration with an amplitude of 10 mm and a period of 5 to 20 Hz is applied. Added for 5 hours. The wafer breakage after the test was confirmed. The case where there was no breakage was rated as “◯”, and the case where breakage was observed was marked as “X”.

[Production Example 1]
(Preparation of polyimide film A)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was replaced with nitrogen, and then 223 parts by mass of 5-amino-2- (p-aminophenyl) benzoxazole and 4416 parts by mass of N, N-dimethylacetamide were added. 40.5 parts by mass of Snowtex (DMAC-ST30, manufactured by Nissan Chemical Industries, Ltd.) (containing 8.1 parts by mass of silica), pyromellitic acid, which is prepared by completely dissolving the colloidal silica in dimethylacetamide. When 217 parts by mass of dianhydride was added and stirred for 24 hours at a reaction temperature of 25 ° C., a brown and viscous polyamic acid solution A was obtained. This reduced viscosity was 3.9 dl / g.
This polyamic acid solution A was coated on a non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 110 ° C. for 5 minutes, and then not peeled off from the support. The polyamic acid film was wound up. The polyamic acid film is passed through a pin tenter having three heat treatment zones, the first stage is 150 ° C. × 2 minutes, the second stage is 220 ° C. × 2 minutes, the third stage is 475 ° C. × 4 minutes, and 20 minutes after passing through the tenter. Six rolls were passed to give a double-side free process, and finally slit to 500 mm width to obtain polyimide film A.
The physical property values of the obtained polyimide film A are shown in Table 1.

[Production Example 2]
(Preparation of polyimide film B)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, 200 parts by mass of diaminodiphenyl ether and 4170 parts by mass of N-methyl-2-pyrrolidone were added and completely dissolved, and then colloidal silica was added. 40.5 parts by mass of Snowtex (DMAC-ST30, manufactured by Nissan Chemical Industries, Ltd.) dispersed in dimethylacetamide (containing 8.1 parts by mass of silica), 217 parts by mass of pyromellitic dianhydride were added, and 25 ° C. When the mixture was stirred at the reaction temperature of 5 hours, a brown viscous polyamic acid solution B was obtained. This reduced viscosity was 3.6 dl / g.
This polyamic acid solution B was coated on a non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 110 ° C. for 5 minutes, and then not peeled off from the support. The polyamic acid film was wound up. The polyamic acid film is passed through a pin tenter having three heat treatment zones, the first stage is 150 ° C. × 2 minutes, the second stage is 220 ° C. × 2 minutes, the third stage is 400 ° C. × 4 minutes, and 20 minutes after passing through the tenter. Six rolls were passed to give a double-side free process, and finally slit to 500 mm width to obtain polyimide film B.
Table 1 shows the physical property values of the obtained polyimide film B.

[Production Example 3]
(Preparation of polyimide film C)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was replaced with nitrogen, 108 parts by mass of phenylenediamine and 4010 parts by mass of N-methyl-2-pyrrolidone were added and completely dissolved, and then colloidal silica was added. Snowtex (DMAC-ST30, manufactured by Nissan Chemical Industries, Ltd.) 40.5 parts by mass (including 8.1 parts by mass of silica) dispersed in dimethylacetamide and 292.5 parts by mass of diphenyltetracarboxylic dianhydride In addition, when the mixture was stirred at a reaction temperature of 25 ° C. for 12 hours, a brown viscous polyamic acid solution C was obtained. This reduced viscosity was 4.3 dl / g.
This polyamic acid solution C was coated on a non-lubricant surface of polyethylene terephthalate film A-4100 (manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 110 ° C. for 5 minutes, and then not peeled off from the support. The polyamic acid film was wound up. The polyamic acid film is passed through a pin tenter having three heat treatment zones, the first stage 150 ° C. × 2 minutes, the second stage 220 ° C. × 2 minutes, the third stage 460 ° C. × 4 minutes, and after passing through the tenter 20 minutes Six rolls were passed to give a double-side free process, and finally slit to a width of 500 mm to obtain a polyimide film C having a thickness of 25 μm.
Table 1 shows the physical property values of the obtained polyimide film C.

[Production Example 4]
(Creation of thermoplastic resin film A)
40 parts by mass of a liquid crystal polymer (Sumikasuper E101, manufactured by Sumitomo Chemical Co., Ltd.) that is polyparahydroxybenzoic acid, a fluororesin that is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (neoflon PFA RAP, manufactured by Daikin Industries, Ltd.) ) 60 parts by mass were blended and melt kneaded using a twin screw extruder (KZW20-25G). The obtained kneaded material was molded into a thermoplastic resin film A having a thickness of 15 μm by a film molding machine in which a T-die having a diameter of 600 mm was attached to the tip of an extruder having a diameter of 40 mm.
Table 2 shows the physical properties of the obtained thermoplastic resin film A (hereinafter sometimes simply referred to as film A).

[Production Example 5]
(Creation of thermoplastic resin film B)
Liquid crystal polymer that is a copolymer of 4,4-dihydroxybiphenol, terephthalic acid, and parahydroxybenzoic acid instead of the liquid crystal polymer that is polyparahydroxybenzoic acid (Sumika Super E101, manufactured by Sumitomo Chemical Co., Ltd.) A thermoplastic resin film B was obtained in the same manner as in Production Example 4 except that (Sumika Super S1000, manufactured by Sumitomo Chemical Co., Ltd.) was used.
Table 2 shows the physical properties of the obtained thermoplastic resin film B (hereinafter sometimes simply referred to as film B).

[Production Example 6]
(Creation of thermoplastic resin film C)
Instead of the liquid crystal polymer that is polyparahydroxybenzoic acid (Sumikasuper E101, manufactured by Sumitomo Chemical Co., Ltd.), the liquid crystal polymer that is a copolymer of 2,6-hydroxynaphthoic acid and parahydroxybenzoic acid (Vectra A950) A thermoplastic resin film C was obtained in the same manner as in Production Example 4, except that Polyplastics) was used.
Table 2 shows physical property values of the obtained thermoplastic resin film C (hereinafter sometimes simply referred to as film C).

[Production Example 7]
(Creation of thermoplastic resin film D)
Instead of the liquid crystal polymer that is polyparahydroxybenzoic acid (Sumika Super E101, manufactured by Sumitomo Chemical Co., Ltd.), the liquid crystal polymer that is a copolymer of ethylene glycol, terephthalic acid, and parahydroxybenzoic acid (Novacurate, A thermoplastic resin film D was obtained in the same manner as in Production Example 4 except that Mitsubishi Engineering Plastics) was used.
Table 2 shows physical property values of the obtained thermoplastic resin film D (hereinafter sometimes simply referred to as film D).

[Production Example 8]
(Creation of thermoplastic resin film E)
Instead of fluororesin (neoflon PFA RAP, manufactured by Daikin Industries), which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, fluororesin (neoflon FEP, Daikin, which is a copolymer of tetrafluoroethylene and hexafluoropropylene) A thermoplastic resin film E was obtained in the same manner as in Production Example 4 except that Kogyo Kogyo Co., Ltd. was used.
Table 2 shows the physical property values of the obtained thermoplastic resin film E (hereinafter sometimes simply referred to as film E).

[Production Example 9]
(Creation of thermoplastic resin film F)
Instead of fluororesin (neoflon PFA RAP, manufactured by Daikin Industries), which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, fluororesin (neoflon ETFE, Daikin Industries, Ltd.) that is a copolymer of tetrafluoroethylene and ethylene A thermoplastic resin film F was obtained in the same manner as in Production Example 4 except for using
Table 2 shows physical property values of the obtained thermoplastic resin film F (hereinafter sometimes simply referred to as film F).

[Production Example 10]
(Creation of thermoplastic resin film G)
A thermoplastic resin film G was obtained in the same manner as in Production Example 4 except that a liquid crystal polymer (Sumikasuper E101, manufactured by Sumitomo Chemical Co., Ltd.), which is polyparahydroxybenzoic acid, was not blended.
Table 3 shows physical property values of the obtained thermoplastic resin film G (hereinafter sometimes simply referred to as film G).

[Production Example 11]
(Creation of thermoplastic resin film H)
20 parts by mass of a liquid crystal polymer (Sumikasuper E101, manufactured by Sumitomo Chemical Co., Ltd.) which is polyparahydroxybenzoic acid, a fluororesin (neoflon PFA RAP, manufactured by Daikin Industries, Ltd.) which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether ) A thermoplastic resin film H was obtained in the same manner as in Production Example 4 except that 80 parts by mass was blended.
Table 3 shows physical property values of the obtained thermoplastic resin film H (hereinafter sometimes simply referred to as film H).

[Production Example 12]
(Creation of thermoplastic resin film I)
80 parts by mass of a liquid crystal polymer (Sumikasuper E101, manufactured by Sumitomo Chemical Co., Ltd.) that is polyparahydroxybenzoic acid, a fluororesin that is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (neoflon PFA RAP, manufactured by Daikin Industries, Ltd.) ) A thermoplastic resin film I was obtained in the same manner as in Production Example 4 except that 20 parts by mass was blended.
Table 3 shows physical property values of the obtained thermoplastic resin film I (hereinafter sometimes simply referred to as film I).

[Production Example 13]
(Creation of thermoplastic resin film J)
An attempt was made to obtain a thermoplastic resin film J in the same manner as in Production Example 4 except that a fluororesin (neoflon PFA RAP, manufactured by Daikin Industries), which is a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, was not blended. However, it was impossible to produce a high-quality film.

[Production Example 14]
(Creation of thermoplastic resin film K)
Instead of using a liquid crystalline polymer that is polyparahydroxybenzoic acid (Sumika Super E101, manufactured by Sumitomo Chemical Co., Ltd.), a PET resin (manufactured by Toyobo Co., Ltd.) that is a copolymer of ethylene glycol and terephthalic acid is used. In the same manner as in Production Example 4, a thermoplastic resin film K was obtained.
Table 3 shows physical property values of the obtained thermoplastic resin film K (hereinafter sometimes simply referred to as film K).

[Production Example 15]
(Creation of thermoplastic resin film L)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then 368.4 g (1.0 mol) of 4,4′-bis (3-aminophenoxy) biphenyl and 59.24 g of phthalic anhydride. (0.4 mol), pyromellitic anhydride 174.5 g (0.8 mol) and m-cresol 2,172 g were charged, heated to 200 ° C. with stirring, and kept at 200 ° C. for 6 hours. Next, toluene was charged into the reaction solution, the precipitate was filtered off, washed several times with toluene, and then dried at 250 ° C. for 6 hours in a nitrogen atmosphere to obtain 510 g of polyimide powder. The polyimide powder was kneaded and melted at 380 to 410 ° C. using a twin screw extruder, extruded and granulated into pellets. The obtained pellets were supplied to a single screw extruder (molding temperature 420 ° C.) having a diameter of 50 mm, passed through a 10 μm leaf disk type filter attached to the front part of the T die, and extruded from a 1100 mm wide T die to be a thermoplastic resin. Film L was obtained.
Table 4 shows physical property values of the obtained thermoplastic resin film L (hereinafter sometimes simply referred to as film L).

[Production Example 16]
(Creation of thermoplastic resin film M)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was replaced with nitrogen, 192 g of trimellitic anhydride, 211 g of o-tolidine diisocyanate (80 mol%), 35 g of 2,4-tolylene diisocyanate, and 1 g of ethylenediamine was charged, and N-methyl-2-pyrrolidone was further charged so that the polymer concentration was 40%. After making it react at 120 degreeC for about 1 hour, it was made to react, further stirring at 180 degreeC for 5 hours. Next, heating was stopped, and while cooling, N-methyl-2-pyrrolidone was further added and diluted to obtain a polyamideimide solution having a solid concentration of 20%.
This polyamideimide solution was coated on a non-lubricant surface of a polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) using a comma coater, dried at 120 ° C. for 3 minutes, and then peeled off from the support. Pass through a pin tenter with two heat treatment zones, heat treatment at 320 ° C. for 2 minutes for the first stage, 320 ° C. for 2 minutes for the second stage, 320 ° C. for 2 minutes for the third stage, slit to 500 mm width, and thermoplastic resin film M was obtained.
Table 4 shows physical property values of the obtained thermoplastic resin film M (hereinafter sometimes simply referred to as film M).
In addition, the content ratio in a table | surface represents the mass% in the thermoplastic resin film of a liquid crystal polymer.

[Example 1]
On one side of the polyimide film A, a thermoplastic resin film A and a single crystal silicon wafer (diameter: about 100 mm, thickness: 0.25 mm) are arranged in this order, and at 330 ° C. and 5 MPa which is higher than the melting point of the thermoplastic resin film. Heat-press molding was performed for 30 minutes to obtain a film-reinforced wafer 1.
Next, a solar cell having a pin junction was formed on a surface where the film of the single crystal silicon wafer was not attached by a general method.
Table 5 shows the evaluation results of the obtained film-reinforced wafer 1 and the photoelectric conversion device 1.

[Examples 2-3]
A laminate was prepared and evaluated in the same manner as in Example 1 except that polyimide films B and C were used instead of polyimide film A.
Table 5 shows the evaluation results of the obtained film-reinforced wafers 2 and 3 and the photoelectric conversion devices 2 and 3.

[Examples 4 to 6]
A laminate was prepared and evaluated in the same manner as in Example 1 except that the thermoplastic resin films B to D were used instead of the thermoplastic resin film A.
Table 5 shows the evaluation results of the obtained film-reinforced wafers 4 to 6 and the photoelectric conversion devices 4 to 6.

[Examples 7 and 8]
A laminate was prepared and evaluated in the same manner as in Example 1 except that the thermoplastic resin films E and F were used instead of the thermoplastic resin film A.
Table 6 shows the evaluation results of the obtained film-reinforced wafers 7 and 8 and the photoelectric conversion devices 7 and 8.

[Examples 9 and 10]
A laminate was prepared and evaluated in the same manner as in Example 1 except that the thermoplastic resin films H and I were used instead of the thermoplastic resin film A.
Table 6 shows the evaluation results of the obtained film-reinforced wafers 9 and 10 and the photoelectric conversion devices 9 and 10.

Example 11
A laminate was prepared in the same manner as in Example 1 except that a single crystal GaAs wafer (diameter 50 mm, thickness 0.4 mm) was used instead of the single crystal silicon wafer (diameter approximately 100 mm, thickness 0.25 mm). And evaluated.
Table 6 shows the evaluation results of the obtained film-reinforced wafer 11 and the photoelectric conversion device 11.

[Comparative Example 1]
A laminate was prepared and evaluated in the same manner as in Example 1 except that the thermoplastic resin film G was used instead of the thermoplastic resin film A.
Table 7 shows the evaluation results of the obtained film-reinforced wafer 12 and the photoelectric conversion device 12.

[Comparative Example 2]
A laminate was prepared and evaluated in the same manner as in Example 1 except that the thermoplastic resin film K was used instead of the thermoplastic resin film A.
Table 7 shows the evaluation results of the obtained film-reinforced wafer 13 and the photoelectric conversion device 13.

[Comparative Example 3]
The same method as in Example 1 except that the thermoplastic resin film L is used instead of the thermoplastic resin film A, and the heat-pressure molding is performed at 390 ° C. and 10 MPa, which is equal to or higher than the melting point of the thermoplastic resin film, for 15 minutes. A laminate was prepared and evaluated.
Table 7 shows the evaluation results of the obtained film-reinforced wafer 14 and the photoelectric conversion device 14.

[Comparative Example 4]
The same as Example 1 except that the thermoplastic resin film M is used instead of the thermoplastic resin film A, and the heat-pressure molding is performed at 330 ° C. and 10 MPa that is equal to or higher than the glass transition temperature of the thermoplastic resin film for 15 minutes. A laminate was prepared by the method of and evaluated.
Table 5 shows the evaluation results of the obtained film-reinforced wafer 15 and the photoelectric conversion device 15.

  The photoelectric conversion device of the present invention has a structure in which a film such as a non-thermoplastic polyimide is laminated on a semiconductor wafer via a specific thermoplastic resin layer, and thus exhibits good handling properties and heat-and-moisture resistance. Peeling hardly occurs even underneath. For this reason, it is possible to reduce the occurrence of defects in mounting processes such as processing processes, modularization, paneling, etc., and it is possible to improve durability and reliability in actual use of photoelectric conversion devices, such as thin solar cells Expected to be used for applications.

Claims (9)

    A photoelectric conversion device in which a polymer film having a glass transition temperature of 70 ° C. or higher is laminated via a thermoplastic resin layer on at least one surface of a semiconductor wafer on which a photoelectric conversion element is formed, wherein the thermoplastic resin layer is fluorine A resin and a thermotropic liquid crystal polymer are contained, the content of the fluororesin in the thermoplastic resin layer is 20 to 80% by mass, and the content of the thermotropic liquid crystal polymer is 20 to 80% by mass. A photoelectric conversion device characterized by that.   The photoelectric conversion device according to claim 1, wherein the thermotropic liquid crystal polymer is a wholly aromatic polyester.   The photoelectric device according to claim 1 or 2, wherein the fluororesin is a thermoplastic fluororesin obtained by copolymerization using a fluorine-containing ethylenic monomer having at least a hydroxyl group and an ethylenic monomer not having a hydroxyl group. Conversion device.   The ethylenic monomer having no hydroxyl group of the fluororesin is one or more selected from tetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinyl ethers. Photoelectric conversion device.   The photoelectric conversion device according to any one of claims 1 to 4, wherein the polymer film is a polyimide film mainly composed of a non-thermoplastic polyimide obtained by polycondensation of aromatic tetracarboxylic acids and aromatic diamines.   2. The polymer film is mainly composed of polyimide benzoxazole obtained by polycondensation of aromatic tetracarboxylic acids and aromatic diamines having a benzoxazole structure, and has a linear expansion coefficient of −10 ppm / ° C. The photoelectric conversion apparatus in any one of -5.   The photoelectric conversion device according to claim 1, wherein the semiconductor wafer is single crystal silicon.   The photoelectric conversion device according to claim 1, wherein the semiconductor wafer is polycrystalline silicon.   The photoelectric conversion device according to claim 1, wherein the semiconductor wafer is a compound semiconductor.