WO2012161107A1 - Coating liquid for diffusing impurity - Google Patents

Coating liquid for diffusing impurity Download PDF

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Publication number
WO2012161107A1
WO2012161107A1 PCT/JP2012/062745 JP2012062745W WO2012161107A1 WO 2012161107 A1 WO2012161107 A1 WO 2012161107A1 JP 2012062745 W JP2012062745 W JP 2012062745W WO 2012161107 A1 WO2012161107 A1 WO 2012161107A1
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WO
WIPO (PCT)
Prior art keywords
coating solution
impurity
group
impurity diffusion
polyhydric alcohol
Prior art date
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PCT/JP2012/062745
Other languages
French (fr)
Japanese (ja)
Inventor
佐藤　弘章
勝間　勝彦
加藤　邦泰
由佳 堤
Original Assignee
日本合成化学工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 日本合成化学工業株式会社 filed Critical 日本合成化学工業株式会社
Priority to KR1020137025806A priority Critical patent/KR20140011354A/en
Priority to CN2012800170092A priority patent/CN103460346A/en
Publication of WO2012161107A1 publication Critical patent/WO2012161107A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
    • H01L21/2225—Diffusion sources
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
    • H01L21/228—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities using diffusion into or out of a solid from or into a liquid phase, e.g. alloy diffusion processes

Definitions

  • the present invention relates to an impurity diffusion coating solution applied on a substrate when an impurity diffusion layer is formed on a semiconductor substrate, and more particularly to an impurity diffusion coating solution suitable for application by screen printing.
  • a liquid material containing impurities such as phosphorus and boron is applied to a semiconductor substrate such as germanium and silicon, a film is formed, and then fired.
  • a method of forming an impurity diffusion layer in a substrate is widely used.
  • a spin coating method As a method for applying such a liquid material on a substrate, a spin coating method is widely used. However, in recent years, when the substrate has been increased in size to reduce the manufacturing cost and becomes a diameter of 4 inches or more, the spin coating method can be applied. It becomes difficult to form a film having a uniform thickness. Therefore, a screen printing method has been studied as a coating method applicable to large wafers, and an impurity-containing diffusion coating solution suitable for such a printing method has been proposed.
  • a diffusion coating solution that can form a uniform film on a semiconductor substrate by screen printing contains a phosphorus compound, a boron compound, a water-soluble polymer, and water as impurities, and has a viscosity within a specific range.
  • Application liquids have been proposed. (For example, see Patent Documents 1 and 2.)
  • the semiconductor obtained by screen-printing and baking the coating solution of Patent Document 1 or 2 has a high impurity content and high uniformity of the film, so that the resistance value variation is small and very excellent.
  • the water in the coating solution may volatilize and thicken. Therefore, a high-boiling organic solvent having a lower volatility than water is used as a solvent, and an organic phosphorus compound soluble in an organic solvent, an organic binder soluble in an organic solvent such as polyvinyl acetate, and a diffusion containing a thixotropic agent.
  • Application liquids have been proposed. (For example, refer to Patent Document 3.)
  • a semiconductor substrate having a film formed with a coating solution for impurity diffusion on the surface is dried and then baked to diffuse impurities into the substrate to form a diffusion layer. It is performed in an upright position in the furnace.
  • the film obtained with the coating solution of Patent Document 3 flows in the initial stage of firing and moves to the lower part of the substrate, so that there is a difference in impurity concentration between the upper and lower sides, and there is a difference in the upper and lower resistance values of the obtained semiconductor. Tended to occur.
  • the present invention provides a coating solution suitable for screen printing, and provides an impurity diffusion coating solution capable of obtaining a semiconductor having a small difference in the upper and lower resistance even when the semiconductor substrate after film formation is baked in an upright state. It is the purpose.
  • PVA resin polyvinyl alcohol resin
  • impurity B
  • polyhydric alcohol C
  • the content of the polyhydric alcohol (C) is 70% by weight or more in the coating solution, and it was found that the problem of the present invention was solved, and the present invention was completed.
  • the present invention is characterized in that, in the impurity diffusion coating solution, a polyhydric alcohol having a boiling point of 100 ° C. or higher is used as a main component of the solvent, and a PVA resin is further contained.
  • a PVA resin is used for the impurity diffusion coating solution.
  • both use a PVA resin that is a water-soluble resin for the coating solution in which water is the main solvent. Therefore, it is usually considered that a PVA-based resin that is insoluble in a normal organic solvent, unstable even if dissolved, and may precipitate depending on environmental changes, is used as a coating solution mainly composed of an organic solvent. It is difficult.
  • the coating solution for impurity diffusion of the present invention is capable of obtaining a uniform film by screen printing on a semiconductor substrate, and is excellent in viscosity stability, so that it can be printed for a long period of time or a pause period. Even if the semiconductor substrate after the film is formed is baked in an upright state, it has advantages such as a difference in impurity concentration, that is, a semiconductor with a small variation in resistance value can be obtained, and is extremely useful industrially. is there.
  • the coating solution for impurity diffusion of the present invention contains a PVA resin (A), an impurity (B), and a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher, and the polyhydric alcohol (C) in the coating solution. Content is 70 weight% or more.
  • the PVA resin (A) is obtained by saponifying a polyvinyl ester resin obtained by copolymerizing a vinyl ester monomer, and is obtained from a vinyl alcohol structural unit and a vinyl acetate structural unit corresponding to the degree of saponification. Composed.
  • the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, versatic.
  • vinyl acid acid etc. are mentioned, vinyl acetate is preferably used economically.
  • the average degree of polymerization (measured according to JIS K 6726) of the PVA resin (A) used in the present invention is usually 100 to 4000, particularly 200 to 2000, more preferably 300 to 1500. . If the average degree of polymerization is too small, the coating solution may have a low viscosity, and it may be difficult to perform good screen printing, or the coating film may become a thin film, resulting in a shortage of impurity supply. On the other hand, if it is too large, it is unsuitable for screen printing and tends to cause printing defects.
  • the PVA resin (A) used in the present invention those having a saponification degree (measured in accordance with JIS K 6726) of 50 to 100 mol% can be usually used.
  • the coating solution of the present invention is a polyhydric alcohol having a boiling point of 100 ° C. or higher because the main component of the solvent, and therefore, has excellent solubility in such a solvent from the viewpoint of the uniformity of the coating solution.
  • a PVA-based resin (A) it is preferable to use one having a low saponification degree or a modified PVA excellent in affinity with a polyhydric alcohol.
  • the saponification degree is preferably 50 to 90 mol%, more preferably 60 to 85 mol%, particularly 70 to 80 mol%. Those are preferred.
  • the degree of saponification is too high, the solubility in a solvent mainly composed of polyhydric alcohol is lowered, and the content may be inevitably reduced.
  • the degree of saponification is too low, when the semiconductor substrate on which the coating film is formed by the coating liquid is erected and baked, the resistance value of the obtained semiconductor may be different between the upper and lower sides of the substrate.
  • modified PVA-based resins those obtained by copolymerizing various monomers during the production of polyvinyl ester-based resins and saponifying them, or those obtained by introducing various functional groups into unmodified PVA by post-modification Can be used.
  • Monomers used for copolymerization with vinyl ester monomers include olefins such as ethylene, propylene, isobutylene, ⁇ -octene, ⁇ -dodecene, ⁇ -octadecene, 3-buten-1-ol, 4-pentene.
  • Derivatives such as hydroxy group-containing ⁇ -olefins such as -1-ol, 5-hexen-1-ol, and 3,4-dihydroxy-1-butene and acylated products thereof, acrylic acid, methacrylic acid, crotonic acid, maleic acid , Unsaturated acids such as maleic anhydride and itaconic acid, salts thereof, monoesters or nitriles such as dialkyl esters, acrylonitrile and methacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, ethylene sulfonic acid, allyl Sulfonic acid, methallylsulfonic acid, etc.
  • Olefin sulfonic acids or salts thereof alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerin monoallyl ether, 3 Vinyl compounds such as 1,4-diacetoxy-1-butene, substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate, vinylidene chloride, 1,4-diacetoxy-2-butene, and vinylene carbonate. .
  • PVA resins having a functional group introduced by a post-reaction include those having an acetoacetyl group by reaction with diketene, those having a polyalkylene oxide group by reaction with ethylene oxide, reaction with an epoxy compound, etc. Examples thereof include those having a hydroxyalkyl group or those obtained by reacting an aldehyde compound having various functional groups with PVA.
  • the modified species in the modified PVA-based resin that is, the constituent units derived from various monomers in the copolymer, or the content of the functional group introduced by the post-reaction, the characteristics greatly depend on the modified species, although it cannot be generally stated, it is usually 1 to 20 mol%, and particularly preferably 2 to 10 mol%.
  • PVA resins having a structural unit having a 1,2-diol structure in the side chain represented by the following general formula (1) are preferably used in the present invention.
  • R 1 , R 2 , and R 3 each independently represent a hydrogen atom or an organic group
  • X represents a single bond or a bonded chain
  • R 4 , R 5 , and R 6 represent Each independently represents a hydrogen atom or an organic group.
  • R 1 to R 3 and R 4 to R 6 in the 1,2-diol structural unit represented by the general formula (1) are all hydrogen atoms, and X is a single bond.
  • a PVA resin having a structural unit represented by ') is most preferred.
  • R 1 to R 3 and R 4 to R 6 in the structural unit represented by the general formula (1) may be organic groups as long as they do not significantly impair the resin characteristics.
  • the organic group include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. May have a functional group such as a halogen group, a hydroxyl group, an ester group, a carboxylic acid group, or a sulfonic acid group, if necessary.
  • X in the 1,2-diol structural unit represented by the general formula (1) is most preferably a single bond from the viewpoint of thermal stability or stability under high temperature or acidic conditions.
  • a bonded chain may be used as long as it does not inhibit the effects of the present invention.
  • Examples of such a bonded chain include hydrocarbons such as alkylene, alkenylene, alkynylene, phenylene, and naphthylene (these hydrocarbons include fluorine, chlorine, bromine, and the like).
  • -O of may be substituted by a halogen) -, - (CH 2 O ) m -, - (OCH 2) m -, - (CH 2 O) m CH 2 -, - CO-, —COCO—, —CO (CH 2 ) m CO—, —CO (C 6 H 4 ) CO—, —S—, —CS—, —SO—, —SO 2 —, —NR—, —CONR—, -NRCO -, - CSNR -, - NRCS -, - NRNR -, - HPO 4 -, - i (OR) 2 -, - OSi (OR) 2 -, - OSi (OR) 2 O -, - Ti (OR) 2 -, - OTi (OR) 2 -, - OTi (OR) 2 O -, - Al (OR)-, -OAl (OR)-, -,
  • R is each independently an arbitrary substituent, preferably a hydrogen atom or an alkyl group, and m is 1 to 5) Integer).
  • the method for producing the PVA resin is not particularly limited, and (i) a method of saponifying a copolymer of a vinyl ester monomer and a compound represented by the following general formula (2), or (ii) a vinyl ester A method of saponifying and decarboxylating a copolymer of a monomer represented by the following general formula (3) and (iii) a copolymer of a vinyl ester monomer and a compound represented by the following general formula (4) A method of saponifying and deketalizing the coalescence is preferably used.
  • R 1 , R 2 , R 3 , X, R 4 , R 5 and R 6 are all the same as in the general formula (1).
  • R 7 and R 8 are each independently a hydrogen atom or R 9 —CO— (wherein R 9 is an alkyl group).
  • R 10 and R 11 are each independently a hydrogen atom or an alkyl group.
  • the method described in JP-A-2006-95825 can be used.
  • the method described in JP-A-2006-95825 it is preferable to use 3,4-diacyloxy-1-butene as the compound represented by the general formula (2) in the method (i).
  • 3,4-diacetoxy-1-butene is preferably used.
  • a saponification degree of 50 to 100 mol% can be used, and further 60 to 90 mol%. In particular, 70 to 80 mol% is preferably used. This is due to the improved solubility in polyhydric alcohols due to the 1,2-diol structure of the side chain, even though the degree of saponification is higher than that of unmodified PVA.
  • the content of 1,2-diol structural units contained in such a PVA resin is usually 1 to 30 mol%, more preferably 3 to 20 mol%, particularly 5 to 10 mol%. . If the content is too low, in the case of a high saponification degree, the solubility in polyhydric alcohol may be insufficient. Conversely, if it is too high, the drying property tends to decrease and the productivity tends to decrease. There is.
  • the content of the 1,2-diol structural unit in the PVA resin (A) is a 1 H-NMR spectrum (solvent: DMSO-d6, internal standard: tetramethylsilane) of a completely saponified PVA resin. Specifically, from the peak area derived from the hydroxyl proton, methine proton, and methylene proton in the 1,2-diol unit, methylene proton in the main chain, hydroxyl proton linked to the main chain, etc. What is necessary is just to calculate.
  • the PVA resin (A) used in the present invention may be one kind or a mixture of two or more kinds.
  • the above-mentioned unmodified PVA, unmodified PVA and general formula are used.
  • PVA resin having the structural unit represented by (1), PVA resin having a structural unit represented by general formula (1) having different saponification degree, polymerization degree, modification degree, etc., unmodified PVA, or general formula A combination of a PVA resin having the structural unit represented by (1) and another modified PVA resin can be used.
  • the content of the PVA resin (A) in the coating solution for impurity diffusion of the present invention is usually 1 to 40% by weight, preferably 3 to 30% by weight, particularly 5 to 25% by weight. . If the content of the PVA resin (A) is too small, the viscosity of the coating solution tends to be low, and the coating film tends to be difficult to be formed stably. Conversely, if too much, the viscosity of the coating solution is high. Therefore, there is a tendency that the coating workability is deteriorated or the screen mesh is easily clogged in screen printing.
  • impurity (B) used in the present invention will be described.
  • an impurity (B) for example, a group 13 element compound or a group 15 element compound is used. Moreover, these compounds may be used independently and may be used together.
  • the group 15 element compound is generally used as an impurity in the production of an N-type semiconductor, and examples thereof include phosphorus compounds and antimony compounds. Among these, phosphorus compounds are preferably used. Such phosphorous compounds can be used as long as they are generally used as impurities in the production of N-type semiconductors. Specifically, phosphoric acids such as phosphoric acid and diphosphorus pentoxide; melamine phosphate and ammonium phosphate Examples thereof include phosphates such as; chlorides such as phosphorus chloride and phosphorus oxychloride; phosphate esters and the like.
  • phosphoric acid, nitric pentoxide, and phosphoric acid esters are exemplified as those having excellent solubility in a polyhydric alcohol having a boiling point of 100 ° C. or higher, which is used as a main component of the solvent, and in particular, phosphoric acid esters are preferably used. It is done.
  • the phosphoric acid esters used in the present invention are those in which all or part of the three hydrogen atoms possessed by phosphoric acid are substituted with organic groups, and various known compounds can be used.
  • Acid phosphoxy (meth) acrylates represented by the general formula (5) are preferably used in terms of suppression of autodoping.
  • R 12 is hydrogen or a methyl group
  • R 13 is hydrogen, a methyl group, or a —CH 2 Cl group
  • R 14 is hydrogen, an alkyl group having 1 to 10 carbon atoms, phenyl Or a —NH 3 C 2 H 4 OH group
  • n is a positive integer of 1 to 10
  • m and l are 1 or 2
  • m + 1 3.
  • R 12 is a methyl group
  • R 13 is hydrogen
  • R 14 is hydrogen
  • n is 1, m is 1 and l is 2
  • R 12 is a methyl group
  • R 13 is hydrogen
  • R 14 is —NH 3 C 2 H 4 OH
  • n is 1, m is 1, and l is 2
  • R 12 And a compound in which R 13 is hydrogen, R 14 is hydrogen, n is 4 to 5, m is 1, and l is 2 (for example, “Phosmer PE” manufactured by Unichemical Co., Ltd.).
  • the content of the group 15 element compound in the coating solution for impurity diffusion of the present invention is usually from 0.1 to 30% by weight, particularly from 0.1 to 10% by weight, particularly from 0.1 to 5% by weight. Is preferably used.
  • the content of the Group 15 element compound with respect to 100 parts by weight of the PVA resin (A) is usually 1 to 300 parts by weight, particularly 2 to 200 parts by weight, particularly 3 to 50 parts by weight.
  • the content of the group 15 element compound is small, the content of the group 15 element (phosphorus or the like) in the diffusion layer is small, and a sufficient resistance value may not be obtained.
  • the solubility of PVA-type resin (A) may become inadequate.
  • Such a Group 15 element compound may be a single compound or a combination of two or more.
  • the group 13 element compound is generally used as an impurity in the production of a P-type semiconductor, and examples thereof include boron compounds and aluminum compounds.
  • boron compounds are preferably used.
  • Specific examples of such boron compounds include boric acids such as boric acid and diboron trioxide; borate salts such as ammonium borate; boron trifluoride, boron trichloride, boron tribromide, boron triiodide, etc. Halides; boric acid esters such as trimethyl borate, triethyl borate, triisopropyl borate; boron nitride, and the like. Of these, boric acid, borates, borate esters, and boron nitride are preferably used from the viewpoint of easy handling.
  • the boric acid esters used in the present invention are those in which all or part of the three hydrogen atoms of boric acid are substituted with organic groups, and various known compounds can be used. Trimethyl acid and triethyl borate are preferably used in terms of impurity diffusibility.
  • the content of the group 13 element compound in the coating solution for impurity diffusion of the present invention is usually from 0.1 to 30% by weight, particularly from 0.1 to 10% by weight, particularly from 0.1 to 5% by weight. Is preferably used.
  • the content of the group 13 element compound with respect to 100 parts by weight of the PVA resin (A) is usually 1 to 300 parts by weight, particularly 3 to 200 parts by weight, particularly 5 to 50 parts by weight.
  • the content of the group 13 element compound is small, the content of the group 13 element (boron or the like) in the diffusion layer is small, and a sufficient resistance value may not be obtained.
  • the solubility of PVA-type resin (A) may become inadequate.
  • the impurity diffusion coating solution of the present invention is characterized in that a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher is used as the main component of the solvent.
  • a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher is used as the main component of the solvent.
  • Such polyhydric alcohol (C) has a boiling point of 100 ° C. or higher, and more preferably 150 to 400 ° C., particularly 175 to 300 ° C.
  • the polyhydric alcohol either an aliphatic alcohol or an aromatic alcohol can be used, but an aliphatic alcohol is preferable from the viewpoint of the solubility of the PVA resin (A).
  • polyhydric alcohol (C) examples include ethylene glycol (197 ° C.), diethylene glycol (244 ° C.), triethylene glycol (287 ° C.), tetraethylene glycol (314 ° C.), and propylene glycol (188 ° C.).
  • Trihydric alcohols such as glycerin (290 ° C.), trimethylolpropane (292 ° C.), sorbitol (296 ° C.), mannitol (290-295 ° C.), pentaerythritol (276 ° C.), polyglycerin and the like
  • polyhydric alcohols The values in parentheses are boiling points.
  • ethylene glycol and glycerin are preferably used, and the blending ratio of ethylene glycol and glycerin varies depending on desired properties, but usually the value of ethylene glycol / glycerin is 20/80 to 100/0, Further, it is selected from the range of 30/70 to 90/10, particularly 50/50 to 80/20.
  • a solvent other than the polyhydric alcohol such as water, isobutyric acid-3-hydroxy-2,2,4-trimethylpentyl ester (TPM), methanol, ethanol, isopropanol.
  • Lower alcohol solvents such as methyl carbitol, ethyl carbitol, butyl carbitol, carbitol solvents, ethyl cellosolve, isoamyl cellosolve, cellosolve solvents such as hexyl cellosolve, other aliphatic hydrocarbon solvents, higher fatty acid solvents
  • solvents and aromatic hydrocarbon solvents examples include solvents and aromatic hydrocarbon solvents.
  • the amount of the solvent other than the polyhydric alcohol is usually 20% by weight or less, particularly 10% by weight or less, based on the total amount of the solvent.
  • the content of the polyhydric alcohol (C) in the coating solution for impurity diffusion of the present invention is 70% by weight or more, more preferably 70 to 90% by weight, especially 75 to 90% by weight. If the content of the polyhydric alcohol (C) is too small, the viscosity of the coating solution becomes too high, and the coating workability tends to be reduced, or the screen mesh tends to be clogged during screen printing. Conversely, if the amount is too large, the viscosity of the coating solution will be too low and the coating will be difficult to form stably, or it will take a long time to dry, and the content of impurities in the diffusion layer will be too low. There is.
  • the impurity diffusion coating solution of the present invention is blended with a surfactant (D). It is preferable to do.
  • the surfactant used in the coating solution of the present invention include known nonionic surfactants, cationic surfactants, and anionic surfactants. Nonionic surfactants are preferred because they bring less components and the like. As such nonionic surfactants, known ones can be used.
  • hydrocarbon surfactants such as block copolymers of ethylene oxide-propylene oxide, acetylene glycol derivatives, silicon And surfactants, fluorine surfactants, and mixtures of organically modified polysiloxanes and special polymers.
  • hydrocarbon surfactants particularly acetylene glycol derivatives, are preferably used because they are excellent in suppressing foaming and defoaming in the coating solution of the present invention.
  • acetylene glycol derivatives those represented by the following formula (6) are preferably used.
  • R 15 and R 18 each independently represents an alkyl group having 1 to 20 carbon atoms, preferably having 1 to 5 carbon atoms, particularly preferably having 3 to 5 carbon atoms.
  • R 16 and R 17 each independently represents an alkyl group having 1 to 3 carbon atoms, and a methyl group is particularly preferably used.
  • R 15 and R 18 and R 16 and R 17 may be the same or different, but those having the same structure are preferably used.
  • s and t are each an integer of 0 to 30, and those in which s + t is 1 to 10, particularly 1 to 5, particularly 1 to 3 are preferably used.
  • acetylene glycol derivatives include 2,5,8,11-tetramethyl-6-dodecin-5,8-diol ethylene oxide adduct, 5,8-dimethyl-6-dodecin-5,8. -Ethylene oxide adduct of diol, ethylene oxide adduct of 2,4,7,9-tetramethyl-5-decyne-4,7 diol, ethylene of 4,7-dimethyl-5-decyne-4,7-diol Oxide adduct, ethylene oxide adduct of 2,3,6,7-tetramethyl-4-octyne-3,6-diol, ethylene oxide adduct of 3,6-dimethyl-4-octyne-3,6-diol And ethylene oxide adduct of 2,5-dimethyl-3-hexyne-2,5-diol. Of these, ethylene oxide adducts of 2,4,7,9-te
  • Examples of such commercially available surfactants that are acetylene glycol derivatives include Surfynol series manufactured by Nissin Chemical Industry Co., Ltd.
  • the amount of the surfactant (D) blended in the coating solution for impurity diffusion of the present invention is usually 0.1 to 10% by weight in the coating solution, particularly 0.3 to 8% by weight, especially 0. The range of 5 to 5% by weight is preferably used. If the blending amount of the surfactant (D) is too small, the effect of suppressing foam and defoaming may be insufficient. Conversely, if the amount is too large, it may be separated from the liquid and a uniform solution may not be obtained.
  • inorganic fine particles (E) Various inorganic fine particles (E) can be blended in the impurity diffusion coating solution of the present invention for the purpose of improving screen printing characteristics.
  • the inorganic fine particles (E) silicas such as colloidal silica, amorphous silica, and fumed silica are suitable, and among them, colloidal silica is preferably used.
  • the amount of such inorganic fine particles (E) is usually 0.5 to 20% by weight in the coating solution, and particularly preferably in the range of 1 to 10% by weight.
  • the coating solution for diffusion of impurities of the present invention contains the above-described PVA resin (A), impurities (B), and polyhydric alcohol (C) having a boiling point of 100 ° C. or higher, and contains the polyhydric alcohol (C).
  • the amount is 70% by weight in the coating solution, and further contains a surfactant (D), inorganic fine particles (E), and other additives as necessary.
  • the viscosity at 20 ° C. of such an impurity diffusion coating solution is usually 300 to 100,000 mPa ⁇ s, preferably 500 to 10,000 mPa ⁇ s, particularly 700 to 6,000 mPa ⁇ s. In addition, this viscosity is measured using a B-type viscometer.
  • the concentration and viscosity of the coating solution are too small, the coating film may not be stably formed or the content of impurities in the diffusion layer may be insufficient. Conversely, the concentration and viscosity are too large. Then, there is a tendency that the coating workability is deteriorated or the screen mesh is easily clogged in the screen printing.
  • the method for preparing the impurity diffusion coating solution of the present invention is not particularly limited.
  • a method in which the above-described PVA resin (A) and impurity (B) are dissolved in polyhydric alcohol (C) sequentially or simultaneously PVA system A method of separately preparing a resin (A) and a polyhydric alcohol (C) solution of impurities (B) and mixing them, and the like, such dissolution, preparation, while heating and stirring Is preferred.
  • the surfactant (D), the inorganic fine particles (E), and other additives any method of blending after the preparation of the coating liquid or blending in the course of the preparation can be employed.
  • the impurity diffusion coating solution of the present invention thus obtained is excellent in storage stability, so it can be prepared and stored in large quantities, moved in small portions, or used halfway to store the rest. It is also possible to do.
  • Such a semiconductor is manufactured by applying the impurity diffusion coating solution of the present invention on a semiconductor substrate such as silicon or germanium, and forming an impurity diffusion layer in the semiconductor substrate through drying, baking, and diffusion steps. Is done.
  • a known method can be used as a method for applying the impurity diffusion coating solution on the semiconductor substrate. Specifically, a screen printing method, a gravure printing method, a relief printing method, a lithographic printing method, a spin coater method. , Comma coater method, die head coater method, die lip coater method, and the like.
  • the coating solution of the present invention is most effective when used in a screen printing method, and a uniform coating film can be obtained even for large wafers of 4 inches or more.
  • the coating amount of the coating solution on the semiconductor substrate varies depending on the type of the substrate, the use of the semiconductor, the content of the impurity compound in the coating solution and the desired impurity content, but is usually 1 to 100 g / m 2 . In particular, it is carried out in the range of 1 to 50 g / m 2 .
  • volatile components such as water are removed from the coating film, and the conditions may be set as appropriate.
  • the temperature is 20 to 300 ° C., particularly 100 to 200 ° C. Minutes, in particular 5 to 30 minutes, are used.
  • the drying method is not particularly limited, and a known method such as hot air drying, infrared heat drying, or vacuum drying can be used.
  • the subsequent firing step (degreasing step) most of the organic components in the coating film are removed using an electric furnace or the like.
  • the conditions of such a process need to be adjusted as appropriate depending on the composition of the coating solution and the thickness of the coating film, but are usually 300 to 1000 ° C., particularly 400 to 800 ° C., 1 to 120 minutes, particularly 5 to 60. Implemented in minutes.
  • impurities are diffused in the semiconductor substrate in the diffusion process, and a diffusion layer is formed.
  • an electric furnace or the like is used, and a single wafer or a plurality of sheets are stacked under a temperature condition of 800 to 1400 ° C. Performed in a combined state. Note that it is possible to omit the diffusion step when the firing step and the diffusion step are performed in one step, or when diffusion proceeds in the baking step and a desired resistance value is obtained.
  • the surface resistance of such semiconductors can be controlled by the impurity content, diffusion temperature, diffusion time, etc., and usually has a surface resistance in the range of 0.03 to 10000 ⁇ / ⁇ suitable for the intended use. It is possible to obtain.
  • the methanol solution was further diluted with methanol, adjusted to a concentration of 30%, charged into a kneader, and a 2% methanol solution of sodium hydroxide was added to the vinyl acetate structural unit in the copolymer while maintaining the solution temperature at 35 ° C.
  • the saponification was carried out by adding Na at a ratio of 3.4 mmol as 1 mol. As saponification progressed, when saponified substances were precipitated and formed into particles, they were separated by filtration, washed well with methanol, and dried in a hot air drier to prepare the intended PVA resin (A1).
  • the saponification degree of the obtained PVA resin (A1) was 78.0 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate.
  • the average degree of polymerization was 1400 as analyzed according to JIS K 6726. (Table 1)
  • the methanol solution was further diluted with methanol, adjusted to a concentration of 30%, charged into a kneader, and a 2% methanol solution of sodium hydroxide was added to the vinyl acetate structural unit in the copolymer while maintaining the solution temperature at 35 ° C.
  • saponification was carried out by adding Na in an amount of 3.4 mmol with respect to 1 mol of the total amount of 3,4-diacetoxy-1-butene structural units. As saponification progressed, when saponified substances were precipitated and formed into particles, they were separated by filtration, washed well with methanol, and dried in a hot air dryer to prepare the intended PVA resin (A2).
  • the degree of saponification of the obtained PVA resin (A2) was 79.7 mol% when analyzed by the alkali consumption required for hydrolysis of residual vinyl acetate and 3,4-diacetoxy-1-butene. .
  • the average degree of polymerization was 450 when analyzed according to JIS K 6726.
  • the content of the 1,2-diol structural unit represented by the general formula (1) is 1 H-NMR (300 MHz proton NMR, d6-DMSO solution, internal standard substance: tetramethylsilane, 50 ° C.). It was 6 mol% when computed from the measured integral value. (Table 1)
  • Example 1 Preparation of coating solution for phosphorus diffusion> To 85 parts of ethylene glycol (C), 10 parts of an unmodified PVA resin (A1) having a saponification degree of 78.0 mol% and an average polymerization degree of 1400 was added and dissolved while heating and stirring. Thereto, 3 parts of diphosphorus pentoxide (B2) is blended as an impurity (B), and R 15 and R 18 in the general formula (6) are 2-methylpropyl groups, R 16 as the surfactant (D).
  • A1 unmodified PVA resin having a saponification degree of 78.0 mol% and an average polymerization degree of 1400 was added and dissolved while heating and stirring. Thereto, 3 parts of diphosphorus pentoxide (B2) is blended as an impurity (B), and R 15 and R 18 in the general formula (6) are 2-methylpropyl groups, R 16 as the surfactant (D).
  • R 17 is a methyl group, s + t ⁇ 1.3, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethylene oxide adduct (“Surfinol 420 manufactured by Nissin Chemical Industry Co., Ltd.) ]) (D1) 2 parts were blended to prepare a phosphorus diffusion coating solution.
  • Squeegee NM squeegee (Hardness: 60) manufactured by Neurong Seimitsu Kogyo Co., Ltd. Squeegee angle: 80 degrees Scraper: NM squeegee manufactured by Neurong Seimitsu Kogyo Co., Ltd. (hardness: 60) Scraper angle: 86 degrees Printing pressure: 0.2 MPa Screen version: manufactured by Tokyo Process Service Co., Ltd.
  • Plate size 450 mm square Mesh type: V330 Emulsion type: TN-1 Emulsion thickness: 10 ⁇ m
  • Pattern: L / S 80 to 220 ⁇ m, every 20 ⁇ m / L ⁇ 3
  • Two 30mm square solid patterns Printing environment: 23 ° C, 60% RH (Evaluation conditions) ⁇ : All patterns were printed. ⁇ : Fading was observed in a part of all printed patterns. X: Some clear chipping was recognized in the pattern.
  • a semiconductor substrate screen-printed with a solid pattern of 150 mm square was dried at 150 ° C. for 2 minutes in a hot air circulating drier under the same printing conditions as described above using the phosphorus diffusion coating solution prepared above. Thereafter, the semiconductor substrate was put upright in a tube furnace at a temperature of 850 ° C., a gas type: nitrogen + oxygen (4%), and a gas flow rate: 50 L / min, held for 15 minutes, taken out, and 46% hydrogen fluoride. Washing was performed while rocking in an aqueous solution. Thus, a semiconductor having a phosphorus diffusion layer in the semiconductor substrate was obtained.
  • the upper part of the obtained semiconductor diffusion layer (the part 30 mm from the top of the diffusion layer when the semiconductor is in an upright state during firing) and the lower part (when the semiconductor is in an upright state as during firing)
  • the surface resistance value of a portion 30 mm from the bottom of the diffusion layer was measured using a resistance measuring instrument (“Lorestar” manufactured by Mitsubishi Analytech Co., Ltd., using a PSP probe). The results are shown in Table 3.
  • Example 2 In Example 1, as the impurity (B), a phosphoric acid ester (acid in which R 12 is a methyl group, R 13 is hydrogen, R 14 is hydrogen, n is 1, m is 1, and l is 2 in the general formula (5) Phosoxymethacrylate (“Phosmer M” manufactured by Unichemical Co., Ltd.)) (B1) 7 parts, a mixture of ethylene glycol and glycerin as polyhydric alcohol (C), and aminoalkoxysilane as surfactant (D)
  • the main component (“SH-21” manufactured by Toray Dow Corning Co., Ltd.) (D2) was used, and the amount of each component was as shown in Table 2.
  • the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
  • Example 3 In Example 1, a mixture of ethylene glycol and glycerin is used as polyhydric alcohol (C), and colloidal silica solution in which 20 wt% colloidal silica is dispersed in 80 wt% water as inorganic fine particles (E) (Fujimi Corporation) 10 parts of “PLANERLITE 4101” manufactured by the manufacturer were blended, and the blending amount of each component was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
  • C polyhydric alcohol
  • E inorganic fine particles
  • Example 4 In Example 2, the PVA resin (A2) obtained in Production Example 2 was used as the PVA resin (A), a mixture of ethylene glycol and glycerin was used as the polyhydric alcohol (C), and the surfactant (D ), And the amount of each component was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
  • Example 5 In Example 4, a water-based emulsion (“Aqualene SB-630” (D3) manufactured by Kyoeisha Chemical Co., Ltd.) containing a mixture of an organically modified polysiloxane and a special polymer was used as the surfactant (D). Other than that, a phosphorus diffusion coating solution was prepared and evaluated in the same manner as in Example 4. Table 3 shows the evaluation results.
  • Example 6 In Example 1, 2 parts of boric acid (B3) was used as the impurity (B), and 86 parts of ethylene glycol (C1) was used. Otherwise, an impurity diffusion coating solution was prepared in the same manner as in Example 1. Using the obtained coating liquid, screen printing was performed on the semiconductor substrate in the same manner as in Example 1 except that an N-type semiconductor substrate was used as the semiconductor substrate, and printability was evaluated. Further, using the above coating solution, semiconductor fabrication and surface resistance measurement were performed according to the following criteria. The results are shown in Table 3.
  • a semiconductor substrate screen-printed with a solid pattern of 150 mm square under the same printing conditions as above was dried at 150 ° C. for 2 minutes in a hot air circulating dryer. Thereafter, the semiconductor substrate was put upright in a tube furnace at a temperature of 950 ° C., a gas type of nitrogen, and a gas flow rate of 50 L / min. After holding for 15 minutes, the nitrogen was stopped and oxygen was allowed to flow at the same flow rate for 15 minutes.
  • the substrate is taken out and washed while being swung in a 46% hydrogen fluoride aqueous solution to obtain a semiconductor having a boron diffusion layer in the semiconductor substrate, and the surface resistance values at the upper and lower portions of the diffusion layer are measured. Measurement was performed in the same manner as in Example 1. The results are shown in Table 3.
  • Example 7 an impurity diffusion coating solution was prepared in the same manner as in Example 2 except that 7 parts of triethyl borate (B4) was used as the impurity (B), and evaluated in the same manner as in Example 6. The evaluation results are shown in Table 3.
  • Example 1 a phosphorus diffusion coating solution was prepared and evaluated in the same manner as in Example 1 except that water was used together with ethylene glycol as the solvent, and the blending amounts of each component were as shown in Table 2. The evaluation results are shown in Table 3.
  • Example 2 In Example 1, instead of PVA resin (A), polyvinyl acetate having an average polymerization degree of 450 was used, phosphoric acid ester (B1) was used as impurity (B), and isobutyric acid-3-hydroxy-2, 2,4-trimethylpentyl ester (TPM) is used, surfactant (D) is not blended, and colloidal silica (“PLALERITE 4101” manufactured by Fujimi Corporation) is blended as inorganic fine particles (E). The amount was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
  • the phosphorus diffusion coating solution of the present invention obtained excellent printability even after being left for a certain time in screen printing. Moreover, the semiconductor obtained from the coating solution of the present invention had a small difference in the upper and lower surface resistance values. On the other hand, the coating solution of Comparative Example 1 using a solvent mainly composed of water is inferior in printability after being left for 30 minutes, and the coating solution of Comparative Example 2 using polyvinyl acetate as a binder is obtained. The difference in the surface resistance value between the upper and lower surfaces of the obtained semiconductor was large.
  • the coating solution for impurity diffusion of the present invention can be printed continuously for a long time or with a rest period, and even if the semiconductor substrate after film formation is baked in an upright state, a semiconductor with small variation in resistance value can be obtained. Since it is obtained, it is extremely useful industrially.

Abstract

A coating liquid for diffusing an impurity, comprising (A) a polyvinyl alcohol-based resin, (B) an impurity and (C) a polyhydric alcohol having a boiling point of 100ºC or higher, wherein the content of the polyhydric alcohol (C) in the coating liquid is 70% by weight or more. Therefore, the coating liquid is suitable for screen printing and enables continuous printing for a long time and printing after an idle period, and even if a semiconductor substrate after forming a coating film is fired in an upright state, a semiconductor in which a difference in resistance between an upper portion and a lower portion is small is obtained.

Description

不純物拡散用塗布液Impurity diffusion coating solution
　本発明は、半導体基板に不純物拡散層を形成する際に、基板上に塗布される不純物拡散用塗布液に関し、さらに詳しくは、スクリーン印刷による塗布に好適な不純物拡散用塗布液に関する。 The present invention relates to an impurity diffusion coating solution applied on a substrate when an impurity diffusion layer is formed on a semiconductor substrate, and more particularly to an impurity diffusion coating solution suitable for application by screen printing.
　トランジスタ、ダイオード、太陽電池などの半導体素子に用いられる半導体の製造法として、ゲルマニウム、シリコン等の半導体基板上にリンやホウ素などの不純物を含有する液状材料を塗布し、皮膜を形成した後、焼成することによって基板中に不純物の拡散層を形成する方法が広く用いられている。 As a method for manufacturing semiconductors used in semiconductor elements such as transistors, diodes, and solar cells, a liquid material containing impurities such as phosphorus and boron is applied to a semiconductor substrate such as germanium and silicon, a film is formed, and then fired. Thus, a method of forming an impurity diffusion layer in a substrate is widely used.
　かかる液状材料を基板上に塗布する方法としてはスピンコート法が広く用いられているが、近年、製造コスト削減のために基板の大型化が進み、直径４インチ以上になると、かかるスピンコート法では均一な膜厚の皮膜形成が困難になる。
　そこで、大型ウェハーにも対応可能な塗布法としてスクリーン印刷法が検討され、かかる印刷法に好適な不純物含有拡散用塗布液が提案されている。 As a method for applying such a liquid material on a substrate, a spin coating method is widely used. However, in recent years, when the substrate has been increased in size to reduce the manufacturing cost and becomes a diameter of 4 inches or more, the spin coating method can be applied. It becomes difficult to form a film having a uniform thickness.
Therefore, a screen printing method has been studied as a coating method applicable to large wafers, and an impurity-containing diffusion coating solution suitable for such a printing method has been proposed.
　例えば、スクリーン印刷によって半導体基板上に均一な皮膜を形成することが可能な拡散用塗布液として、不純物としてリン化合物やホウ素化合物、水溶性高分子、水を含有し、粘度が特定範囲である拡散用塗布液が提案されている。（例えば、特許文献１、２参照。） For example, a diffusion coating solution that can form a uniform film on a semiconductor substrate by screen printing contains a phosphorus compound, a boron compound, a water-soluble polymer, and water as impurities, and has a viscosity within a specific range. Application liquids have been proposed. (For example, see Patent Documents 1 and 2.)
　特許文献１、あるいは２の塗布液をスクリーン印刷し、焼成して得られた半導体は、不純物の含有量が高く、皮膜の均一性が高いため、抵抗値のばらつきが小さく、非常に優れたものであるが、使用時の環境によっては塗布液中の水が揮発、増粘する場合があった。
　そこで、溶剤として水よりも揮発性が低い高沸点の有機溶剤を用い、有機溶剤に可溶な有機リン化合物、有機溶剤に可溶なポリ酢酸ビニルなどの有機バインダー、およびチクソ剤を含有する拡散用塗布液が提案されている。（例えば、特許文献３参照。） The semiconductor obtained by screen-printing and baking the coating solution of Patent Document 1 or 2 has a high impurity content and high uniformity of the film, so that the resistance value variation is small and very excellent. However, depending on the environment during use, the water in the coating solution may volatilize and thicken.
Therefore, a high-boiling organic solvent having a lower volatility than water is used as a solvent, and an organic phosphorus compound soluble in an organic solvent, an organic binder soluble in an organic solvent such as polyvinyl acetate, and a diffusion containing a thixotropic agent. Application liquids have been proposed. (For example, refer to Patent Document 3.)
特開２００７－５３３５３号公報JP 2007-53353 A 特開２００７－３５７１９号公報JP 2007-35719 A ＷＯ２００９／１１６５６９号公報WO2009 / 116569
　表面に不純物拡散用塗布液による皮膜が形成された半導体基板は、乾燥後、焼成することによって基板中に不純物が拡散して拡散層が形成されるが、通常、かかる焼成は、多数の基板を炉の中に直立させて並べた状態で行われる。
　ところが、特許文献３の塗布液で得られた皮膜は、焼成の初期段階で流動し、基板下部に移動するためか上下で不純物濃度の差が生じ、得られた半導体の抵抗値に上下で差が生じる傾向があった。 A semiconductor substrate having a film formed with a coating solution for impurity diffusion on the surface is dried and then baked to diffuse impurities into the substrate to form a diffusion layer. It is performed in an upright position in the furnace.
However, the film obtained with the coating solution of Patent Document 3 flows in the initial stage of firing and moves to the lower part of the substrate, so that there is a difference in impurity concentration between the upper and lower sides, and there is a difference in the upper and lower resistance values of the obtained semiconductor. Tended to occur.
　すなわち本発明は、スクリーン印刷に好適な塗布液であって、皮膜形成後の半導体基板を直立状態で焼成したとしても抵抗値の上下の差が小さい半導体が得られる不純物拡散用塗布液の提供を目的とするものである。 That is, the present invention provides a coating solution suitable for screen printing, and provides an impurity diffusion coating solution capable of obtaining a semiconductor having a small difference in the upper and lower resistance even when the semiconductor substrate after film formation is baked in an upright state. It is the purpose.
　本発明者は、上記事情に鑑み鋭意検討した結果、ポリビニルアルコール系樹脂（以下、ＰＶＡ系樹脂と略記する。）（Ａ）、不純物（Ｂ）、および沸点が１００℃以上の多価アルコール（Ｃ）を含有し、該多価アルコール（Ｃ）の含有量が塗布液中の７０重量％以上である不純物拡散用塗布液によって本発明の課題が解決されることを見出し、本発明を完成した。 As a result of intensive studies in view of the above circumstances, the present inventor has found that a polyvinyl alcohol resin (hereinafter abbreviated as PVA resin) (A), an impurity (B), and a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher. ) And the content of the polyhydric alcohol (C) is 70% by weight or more in the coating solution, and it was found that the problem of the present invention was solved, and the present invention was completed.
　すなわち本発明は、不純物拡散用塗布液において、溶剤の主成分として沸点１００℃以上の多価アルコールを用い、さらにＰＶＡ系樹脂を含有させることを最大の特徴とするものである。
　なお、不純物拡散用塗布液にＰＶＡ系樹脂を用いることは特許文献１、２などにおいて公知であるが、いずれも水が主溶剤である塗布液に水溶性樹脂であるＰＶＡ系樹脂を用いたもので、通常の有機溶剤には不溶であり、溶解したとしても不安定で、環境変化によっては析出する可能性があるＰＶＡ系樹脂を有機溶剤を主体とする塗布液に用いることは、通常、考えにくいことである。 That is, the present invention is characterized in that, in the impurity diffusion coating solution, a polyhydric alcohol having a boiling point of 100 ° C. or higher is used as a main component of the solvent, and a PVA resin is further contained.
In addition, it is well known in Patent Documents 1 and 2 that the PVA resin is used for the impurity diffusion coating solution. However, both use a PVA resin that is a water-soluble resin for the coating solution in which water is the main solvent. Therefore, it is usually considered that a PVA-based resin that is insoluble in a normal organic solvent, unstable even if dissolved, and may precipitate depending on environmental changes, is used as a coating solution mainly composed of an organic solvent. It is difficult.
　本発明の不純物拡散用塗布液は半導体基板上にスクリーン印刷することによって均一な皮膜が得られる点、粘度安定性に優れることから、長時間の連続印刷や休止期間をおいた印刷が可能である点、皮膜形成後の半導体基板を直立状態で焼成したとしても不純物濃度の上下差、すなわち抵抗値の上下バラツキが小さい半導体が得られる点、などの利点を有するもので、工業的に極めて有用である。 The coating solution for impurity diffusion of the present invention is capable of obtaining a uniform film by screen printing on a semiconductor substrate, and is excellent in viscosity stability, so that it can be printed for a long period of time or a pause period. Even if the semiconductor substrate after the film is formed is baked in an upright state, it has advantages such as a difference in impurity concentration, that is, a semiconductor with a small variation in resistance value can be obtained, and is extremely useful industrially. is there.
　以下に記載する構成要件の説明は、本発明の実施態様の一例（代表例）であり、これらの内容に特定されるものではない。
　以下、本発明について詳細に説明する。 The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and is not limited to these contents.
Hereinafter, the present invention will be described in detail.
　本発明の不純物拡散用塗布液は、ＰＶＡ系樹脂（Ａ）、不純物（Ｂ）、および沸点が１００℃以上の多価アルコール（Ｃ）を含有し、塗布液中の多価アルコール（Ｃ）の含有量が７０重量％以上のものである。
　以下、各順に説明する。 The coating solution for impurity diffusion of the present invention contains a PVA resin (A), an impurity (B), and a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher, and the polyhydric alcohol (C) in the coating solution. Content is 70 weight% or more.
Hereinafter, each will be described in order.
〔ＰＶＡ系樹脂（Ａ）〕
　まず、本発明で用いられるＰＶＡ系樹脂（Ａ）について説明する。
　ＰＶＡ系樹脂（Ａ）は、ビニルエステル系単量体を共重合して得られるポリビニルエステル系樹脂をケン化して得られるものであり、ケン化度相当のビニルアルコール構造単位と酢酸ビニル構造単位から構成される。
　上記ビニルエステル系モノマーとしては、ギ酸ビニル、酢酸ビニル、プロピオン酸ビニル、バレリン酸ビニル、酪酸ビニル、イソ酪酸ビニル、ピバリン酸ビニル、カプリン酸ビニル、ラウリン酸ビニル、ステアリン酸ビニル、安息香酸ビニル、バーサチック酸ビニル等が挙げられるが、経済的に酢酸ビニルが好ましく用いられる。 [PVA resin (A)]
First, the PVA resin (A) used in the present invention will be described.
The PVA resin (A) is obtained by saponifying a polyvinyl ester resin obtained by copolymerizing a vinyl ester monomer, and is obtained from a vinyl alcohol structural unit and a vinyl acetate structural unit corresponding to the degree of saponification. Composed.
Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, versatic. Although vinyl acid acid etc. are mentioned, vinyl acetate is preferably used economically.
　本発明で用いられるＰＶＡ系樹脂（Ａ）の平均重合度（ＪＩＳ　Ｋ　６７２６に準拠して測定）は、通常、１００～４０００であり、特に２００～２０００、さらに３００～１５００のものが好ましく用いられる。
　かかる平均重合度が小さすぎると塗布液が低粘度となり、良好なスクリーン印刷が困難となったり、塗膜が薄膜となり、不純物の供給量が不足する場合がある。逆に大きすぎてもスクリーン印刷には不適であり、印刷不良が発生しやすくなる傾向がある。 The average degree of polymerization (measured according to JIS K 6726) of the PVA resin (A) used in the present invention is usually 100 to 4000, particularly 200 to 2000, more preferably 300 to 1500. .
If the average degree of polymerization is too small, the coating solution may have a low viscosity, and it may be difficult to perform good screen printing, or the coating film may become a thin film, resulting in a shortage of impurity supply. On the other hand, if it is too large, it is unsuitable for screen printing and tends to cause printing defects.
　また、本発明で用いられるＰＶＡ系樹脂（Ａ）としては、通常、ケン化度（ＪＩＳ　Ｋ　６７２６に準拠して測定）が５０～１００モル％のものを用いることが可能である。
　中でも、本発明の塗布液は、その溶剤の主成分が、沸点が１００℃以上の多価アルコールであることから、塗布液の均一性の観点から、かかる溶剤への溶解性に優れたものが好ましく、そのようなＰＶＡ系樹脂（Ａ）としては、ケン化度が低いものや、多価アルコールとの親和性に優れた変性ＰＶＡを用いることが好ましい。 In addition, as the PVA resin (A) used in the present invention, those having a saponification degree (measured in accordance with JIS K 6726) of 50 to 100 mol% can be usually used.
Among them, the coating solution of the present invention is a polyhydric alcohol having a boiling point of 100 ° C. or higher because the main component of the solvent, and therefore, has excellent solubility in such a solvent from the viewpoint of the uniformity of the coating solution. Preferably, as such a PVA-based resin (A), it is preferable to use one having a low saponification degree or a modified PVA excellent in affinity with a polyhydric alcohol.
　例えば、本発明のＰＶＡ系樹脂（Ａ）として未変性のＰＶＡを用いる場合には、ケン化度が５０～９０モル％のものが好ましく、さらに６０～８５モル％、特に７０～８０モル％のものが好ましい。未変性ＰＶＡの場合、そのケン化度が高すぎると多価アルコールを主体とする溶剤への溶解性が低下し、含有量を減らさざるをえない場合がある。また、ケン化度が低すぎると塗布液によって塗布皮膜が形成された半導体基板を直立させて焼成した場合、得られた半導体の抵抗値が基板の上下で差が生じる場合がある。 For example, when unmodified PVA is used as the PVA resin (A) of the present invention, the saponification degree is preferably 50 to 90 mol%, more preferably 60 to 85 mol%, particularly 70 to 80 mol%. Those are preferred. In the case of unmodified PVA, if the degree of saponification is too high, the solubility in a solvent mainly composed of polyhydric alcohol is lowered, and the content may be inevitably reduced. On the other hand, if the degree of saponification is too low, when the semiconductor substrate on which the coating film is formed by the coating liquid is erected and baked, the resistance value of the obtained semiconductor may be different between the upper and lower sides of the substrate.
　また、変性ＰＶＡ系樹脂としては、ポリビニルエステル系樹脂の製造時に各種単量体を共重合させ、これをケン化して得られたものや、未変性ＰＶＡに後変性によって各種官能基を導入したものを用いることができる。 In addition, as modified PVA-based resins, those obtained by copolymerizing various monomers during the production of polyvinyl ester-based resins and saponifying them, or those obtained by introducing various functional groups into unmodified PVA by post-modification Can be used.
　ビニルエステル系モノマーとの共重合に用いられる単量体としては、エチレンやプロピレン、イソブチレン、α－オクテン、α－ドデセン、α－オクタデセン等のオレフィン類、３－ブテン－１－オール、４－ペンテン－１－オール、５－ヘキセン－１－オール、３，４－ジヒドロキシ－１－ブテン等のヒドロキシ基含有α－オレフィン類およびそのアシル化物などの誘導体、アクリル酸、メタクリル酸、クロトン酸、マレイン酸、無水マレイン酸、イタコン酸等の不飽和酸類、その塩、モノエステル、あるいはジアルキルエステル、アクリロニトリル、メタアクリロニトリル等のニトリル類、ジアセトンアクリルアミド、アクリルアミド、メタクリルアミド等のアミド類、エチレンスルホン酸、アリルスルホン酸、メタアリルスルホン酸等のオレフィンスルホン酸類あるいはその塩、アルキルビニルエーテル類、ジメチルアリルビニルケトン、Ｎ－ビニルピロリドン、塩化ビニル、ビニルエチレンカーボネート、２，２－ジアルキル－４－ビニル－１，３－ジオキソラン、グリセリンモノアリルエーテル、３，４－ジアセトキシ－１－ブテン、等のビニル化合物、酢酸イソプロペニル、１－メトキシビニルアセテート等の置換酢酸ビニル類、塩化ビニリデン、１，４－ジアセトキシ－２－ブテン、ビニレンカーボネート、等が挙げられる。 Monomers used for copolymerization with vinyl ester monomers include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, 3-buten-1-ol, 4-pentene. Derivatives such as hydroxy group-containing α-olefins such as -1-ol, 5-hexen-1-ol, and 3,4-dihydroxy-1-butene and acylated products thereof, acrylic acid, methacrylic acid, crotonic acid, maleic acid , Unsaturated acids such as maleic anhydride and itaconic acid, salts thereof, monoesters or nitriles such as dialkyl esters, acrylonitrile and methacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, ethylene sulfonic acid, allyl Sulfonic acid, methallylsulfonic acid, etc. Olefin sulfonic acids or salts thereof, alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerin monoallyl ether, 3 Vinyl compounds such as 1,4-diacetoxy-1-butene, substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate, vinylidene chloride, 1,4-diacetoxy-2-butene, and vinylene carbonate. .
　また、後反応によって官能基が導入されたＰＶＡ系樹脂としては、ジケテンとの反応によるアセトアセチル基を有するもの、エチレンオキサイドとの反応によるポリアルキレンオキサイド基を有するもの、エポキシ化合物等との反応によるヒドロキシアルキル基が有するもの、あるいは各種官能基を有するアルデヒド化合物をＰＶＡと反応させて得られたものなどを挙げることができる。
　かかる変性ＰＶＡ系樹脂中の変性種、すなわち共重合体中の各種単量体に由来する構成単位、あるいは後反応によって導入された官能基の含有量は、変性種によって特性が大きくことなるため、一概には言えないが、通常、１～２０モル％であり、特に２～１０モル％の範囲が好ましく用いられる。 In addition, PVA resins having a functional group introduced by a post-reaction include those having an acetoacetyl group by reaction with diketene, those having a polyalkylene oxide group by reaction with ethylene oxide, reaction with an epoxy compound, etc. Examples thereof include those having a hydroxyalkyl group or those obtained by reacting an aldehyde compound having various functional groups with PVA.
The modified species in the modified PVA-based resin, that is, the constituent units derived from various monomers in the copolymer, or the content of the functional group introduced by the post-reaction, the characteristics greatly depend on the modified species, Although it cannot be generally stated, it is usually 1 to 20 mol%, and particularly preferably 2 to 10 mol%.
　これらの各種変性ＰＶＡ系樹脂の中でも、本発明においては、下記一般式（１）で示される側鎖に１，２－ジオール構造を有する構造単位を有するＰＶＡ系樹脂が好ましく用いられる。
　なお、一般式（１）におけるＲ1、Ｒ2、及びＲ3はそれぞれ独立して水素原子または有機基を示し、Ｘは単結合または結合鎖を示し、Ｒ4、Ｒ5、及びＲ6はそれぞれ独立して水素原子または有機基を示すものである。 Among these various modified PVA resins, PVA resins having a structural unit having a 1,2-diol structure in the side chain represented by the following general formula (1) are preferably used in the present invention.
In the general formula (1), R 1 , R 2 , and R 3 each independently represent a hydrogen atom or an organic group, X represents a single bond or a bonded chain, and R 4 , R 5 , and R 6 represent Each independently represents a hydrogen atom or an organic group.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　中でも、一般式（１）で表わされる１，２－ジオール構造単位中のＲ1～Ｒ3、及びＲ4～Ｒ6がすべて水素原子であり、Ｘが単結合である、下記一般式（１’）で表わされる構造単位を有するＰＶＡ系樹脂が最も好ましい。 In particular, R 1 to R 3 and R 4 to R 6 in the 1,2-diol structural unit represented by the general formula (1) are all hydrogen atoms, and X is a single bond. A PVA resin having a structural unit represented by ') is most preferred.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　なお、かかる一般式（１）で表わされる構造単位中のＲ1～Ｒ3、及びＲ4～Ｒ6は、樹脂特性を大幅に損なわない程度の量であれば有機基であってもよく、その有機基としては、例えばメチル基、エチル基、ｎ－プロピル基、イソプロピル基、ｎ－ブチル基、イソブチル基、ｔｅｒｔ－ブチル基等の炭素数１～４のアルキル基が挙げられ、かかる有機基は、必要に応じて、ハロゲン基、水酸基、エステル基、カルボン酸基、スルホン酸基等の官能基を有していてもよい。 Note that R 1 to R 3 and R 4 to R 6 in the structural unit represented by the general formula (1) may be organic groups as long as they do not significantly impair the resin characteristics. Examples of the organic group include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. May have a functional group such as a halogen group, a hydroxyl group, an ester group, a carboxylic acid group, or a sulfonic acid group, if necessary.
　また、一般式（１）で表わされる１，２－ジオール構造単位中のＸは熱安定性の点や高温下や酸性条件下での安定性の点で単結合であるものが最も好ましいが、本発明の効果を阻害しない範囲であれば結合鎖であってもよく、かかる結合鎖としては、アルキレン、アルケニレン、アルキニレン、フェニレン、ナフチレン等の炭化水素（これらの炭化水素はフッ素、塩素、臭素等のハロゲン等で置換されていても良い）の他、－Ｏ－、－（ＣＨ2Ｏ）m－、－（ＯＣＨ2）m－、－（ＣＨ2Ｏ）mＣＨ2－、－ＣＯ－、－ＣＯＣＯ－、－ＣＯ（ＣＨ2）mＣＯ－、－ＣＯ（Ｃ6Ｈ4）ＣＯ－、－Ｓ－、－ＣＳ－、－ＳＯ－、－ＳＯ2－、－ＮＲ－、－ＣＯＮＲ－、－ＮＲＣＯ－、－ＣＳＮＲ－、－ＮＲＣＳ－、－ＮＲＮＲ－、－ＨＰＯ4－、－Ｓｉ（ＯＲ）2－、－ＯＳｉ（ＯＲ）2－、－ＯＳｉ（ＯＲ）2Ｏ－、－Ｔｉ（ＯＲ）2－、－ＯＴｉ（ＯＲ）2－、－ＯＴｉ（ＯＲ）2Ｏ－、－Ａｌ（ＯＲ）－、－ＯＡｌ（ＯＲ）－、－ＯＡｌ（ＯＲ）Ｏ－、等（Ｒは各々独立して任意の置換基であり、水素原子、アルキル基が好ましく、またｍは１～５の整数）が挙げられる。中でも製造時あるいは使用時の安定性の点で炭素数６以下のアルキレン基、特にメチレン基、あるいは－ＣＨ2ＯＣＨ2－が好ましい。 Further, X in the 1,2-diol structural unit represented by the general formula (1) is most preferably a single bond from the viewpoint of thermal stability or stability under high temperature or acidic conditions. A bonded chain may be used as long as it does not inhibit the effects of the present invention. Examples of such a bonded chain include hydrocarbons such as alkylene, alkenylene, alkynylene, phenylene, and naphthylene (these hydrocarbons include fluorine, chlorine, bromine, and the like). other, -O of may be substituted by a halogen) -, - (CH 2 O ) m -, - (OCH 2) m -, - (CH 2 O) m CH 2 -, - CO-, —COCO—, —CO (CH 2 ) m CO—, —CO (C 6 H 4 ) CO—, —S—, —CS—, —SO—, —SO 2 —, —NR—, —CONR—, -NRCO -, - CSNR -, - NRCS -, - NRNR -, - HPO 4 -, - i (OR) 2 -, - OSi (OR) 2 -, - OSi (OR) 2 O -, - Ti (OR) 2 -, - OTi (OR) 2 -, - OTi (OR) 2 O -, - Al (OR)-, -OAl (OR)-, -OAl (OR) O-, etc. (R is each independently an arbitrary substituent, preferably a hydrogen atom or an alkyl group, and m is 1 to 5) Integer). Among them, an alkylene group having 6 or less carbon atoms, particularly a methylene group or —CH 2 OCH 2 — is preferable from the viewpoint of stability during production or use.
　かかるＰＶＡ系樹脂の製造法としては、特に限定されないが、（ｉ）ビニルエステル系モノマーと下記一般式（２）で示される化合物との共重合体をケン化する方法や、（ｉｉ）ビニルエステル系モノマーと下記一般式（３）で示される化合物との共重合体をケン化及び脱炭酸する方法や、（ｉｉｉ）ビニルエステル系モノマーと下記一般式（４）で示される化合物との共重合体をケン化及び脱ケタール化する方法が好ましく用いられる。 The method for producing the PVA resin is not particularly limited, and (i) a method of saponifying a copolymer of a vinyl ester monomer and a compound represented by the following general formula (2), or (ii) a vinyl ester A method of saponifying and decarboxylating a copolymer of a monomer represented by the following general formula (3) and (iii) a copolymer of a vinyl ester monomer and a compound represented by the following general formula (4) A method of saponifying and deketalizing the coalescence is preferably used.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　上記一般式（２）、（３）、（４）中のＲ1、Ｒ2、Ｒ3、Ｘ、Ｒ4、Ｒ5、Ｒ6は、いずれも一般式（１）の場合と同様である。また、Ｒ7及びＲ8はそれぞれ独立して水素原子またはＲ9－ＣＯ－（式中、Ｒ9はアルキル基である）である。Ｒ10及びＲ11はそれぞれ独立して水素原子またはアルキル基である。 In the general formulas (2), (3) and (4), R 1 , R 2 , R 3 , X, R 4 , R 5 and R 6 are all the same as in the general formula (1). . R 7 and R 8 are each independently a hydrogen atom or R 9 —CO— (wherein R 9 is an alkyl group). R 10 and R 11 are each independently a hydrogen atom or an alkyl group.
　（ｉ）、（ｉｉ）、及び（ｉｉｉ）の方法については、例えば、特開２００６－９５８２５に説明されている方法を用いることができる。
　中でも、共重合反応性および工業的な取り扱い性に優れるという点から、（ｉ）の方法において、一般式（２）で表わされる化合物として３，４－ジアシロキシ－１－ブテンを用いることが好ましく、特に３，４－ジアセトキシ－１－ブテンが好ましく用いられる。 As the methods (i), (ii), and (iii), for example, the method described in JP-A-2006-95825 can be used.
Among these, from the viewpoint of excellent copolymerization reactivity and industrial handleability, it is preferable to use 3,4-diacyloxy-1-butene as the compound represented by the general formula (2) in the method (i). In particular, 3,4-diacetoxy-1-butene is preferably used.
　本発明において、かかる一般式（１）で表される構造単位を有するＰＶＡ系樹脂を用いる場合、ケン化度が５０～１００モル％のものを用いることが可能であり、さらに６０～９０モル％、特に７０～８０モル％のものが好ましく用いられる。
　これは、側鎖の１，２－ジオール構造によって、未変性ＰＶＡよりケン化度が高くても、多価アルコールへの溶解性が向上したことによるものである。 In the present invention, when a PVA resin having the structural unit represented by the general formula (1) is used, a saponification degree of 50 to 100 mol% can be used, and further 60 to 90 mol%. In particular, 70 to 80 mol% is preferably used.
This is due to the improved solubility in polyhydric alcohols due to the 1,2-diol structure of the side chain, even though the degree of saponification is higher than that of unmodified PVA.
　また、かかるＰＶＡ系樹脂に含まれる１，２－ジオール構造単位の含有量は、通常、１～３０モル％であり、さらに３～２０モル％、特に５～１０モル％のものが好ましく用いられる。かかる含有量が低すぎると、高ケン化度のものの場合、多価アルコールへの溶解性が不十分になる場合があり、逆に高すぎると、乾燥性が低下し、生産性が低下する傾向がある。 In addition, the content of 1,2-diol structural units contained in such a PVA resin is usually 1 to 30 mol%, more preferably 3 to 20 mol%, particularly 5 to 10 mol%. . If the content is too low, in the case of a high saponification degree, the solubility in polyhydric alcohol may be insufficient. Conversely, if it is too high, the drying property tends to decrease and the productivity tends to decrease. There is.
　なお、ＰＶＡ系樹脂（Ａ）中の１，２－ジオール構造単位の含有率は、ＰＶＡ系樹脂を完全にケン化したものの1Ｈ－ＮＭＲスペクトル（溶媒：ＤＭＳＯ－ｄ６、内部標準：テトラメチルシラン）から求めることができ、具体的には１，２－ジオール単位中の水酸基プロトン、メチンプロトン、およびメチレンプロトン、主鎖のメチレンプロトン、主鎖に連結する水酸基のプロトンなどに由来するピーク面積から算出すればよい。 The content of the 1,2-diol structural unit in the PVA resin (A) is a 1 H-NMR spectrum (solvent: DMSO-d6, internal standard: tetramethylsilane) of a completely saponified PVA resin. Specifically, from the peak area derived from the hydroxyl proton, methine proton, and methylene proton in the 1,2-diol unit, methylene proton in the main chain, hydroxyl proton linked to the main chain, etc. What is necessary is just to calculate.
　また、本発明で用いられるＰＶＡ系樹脂（Ａ）は、一種類であっても、二種類以上の混合物であってもよく、その場合は、上述の未変性ＰＶＡどうし、未変性ＰＶＡと一般式（１）で示される構造単位を有するＰＶＡ系樹脂、ケン化度、重合度、変性度などが異なる一般式（１）で示される構造単位を有するＰＶＡ系樹脂どうし、未変性ＰＶＡ、あるいは一般式（１）で示される構造単位を有するＰＶＡ系樹脂と他の変性ＰＶＡ系樹脂、などの組合わせを用いることができる。 Further, the PVA resin (A) used in the present invention may be one kind or a mixture of two or more kinds. In that case, the above-mentioned unmodified PVA, unmodified PVA and general formula are used. PVA resin having the structural unit represented by (1), PVA resin having a structural unit represented by general formula (1) having different saponification degree, polymerization degree, modification degree, etc., unmodified PVA, or general formula A combination of a PVA resin having the structural unit represented by (1) and another modified PVA resin can be used.
　本発明の不純物拡散用塗布液中のＰＶＡ系樹脂（Ａ）の含有量は、通常１～４０重量％であり、特に３～３０重量％、殊に５～２５重量％の範囲が好ましく用いられる。
　かかるＰＶＡ系樹脂（Ａ）の含有量が小さすぎると、塗布液の粘度が低くなり、塗膜が安定して形成されにくくなる傾向があり、逆に、多すぎると、塗布液の粘度が高くなるため、塗布作業性が低下したり、スクリーン印刷におけるスクリーンメッシュの目詰まりが起りやすくなる傾向がある。 The content of the PVA resin (A) in the coating solution for impurity diffusion of the present invention is usually 1 to 40% by weight, preferably 3 to 30% by weight, particularly 5 to 25% by weight. .
If the content of the PVA resin (A) is too small, the viscosity of the coating solution tends to be low, and the coating film tends to be difficult to be formed stably. Conversely, if too much, the viscosity of the coating solution is high. Therefore, there is a tendency that the coating workability is deteriorated or the screen mesh is easily clogged in screen printing.
〔不純物（Ｂ）〕
　次に、本発明で用いられる不純物（Ｂ）について説明する。
　かかる不純物（Ｂ）としては、例えば、１３族元素化合物や１５族元素化合物が用いられる。また、これらの化合物は、単独で用いてもよく、併用してもよい。 [Impurity (B)]
Next, the impurity (B) used in the present invention will be described.
As such an impurity (B), for example, a group 13 element compound or a group 15 element compound is used. Moreover, these compounds may be used independently and may be used together.
　上記１５族元素化合物は、一般にＮ型半導体の製造において、不純物として用いられるものであり、リン化合物やアンチモン化合物を挙げることができるが、中でもリン化合物が好ましく用いられる。
　かかるリン化合物としては、一般にＮ型半導体の製造において不純物として用いられるものであれば使用可能であり、具体的には、リン酸、五酸化二リンなどのリン酸類；リン酸メラミン、リン酸アンモニウムなどのリン酸塩類；塩化リン、オキシ塩化リンなどの塩化物；リン酸エステル類などを挙げることができる。
　中でも、溶剤の主成分として用いられる沸点１００℃以上の多価アルコールへの溶解性に優れたものとして、リン酸や五酸化ニリン、リン酸エステル類が挙げられ、特にリン酸エステル類が好ましく用いられる。 The group 15 element compound is generally used as an impurity in the production of an N-type semiconductor, and examples thereof include phosphorus compounds and antimony compounds. Among these, phosphorus compounds are preferably used.
Such phosphorous compounds can be used as long as they are generally used as impurities in the production of N-type semiconductors. Specifically, phosphoric acids such as phosphoric acid and diphosphorus pentoxide; melamine phosphate and ammonium phosphate Examples thereof include phosphates such as; chlorides such as phosphorus chloride and phosphorus oxychloride; phosphate esters and the like.
Among them, phosphoric acid, nitric pentoxide, and phosphoric acid esters are exemplified as those having excellent solubility in a polyhydric alcohol having a boiling point of 100 ° C. or higher, which is used as a main component of the solvent, and in particular, phosphoric acid esters are preferably used. It is done.
　本発明において用いられるリン酸エステル類とは、リン酸の持つ３つの水素の全部、あるいは一部が有機基で置換されたもので、公知の各種化合物を用いることが可能であるが、中でも下記一般式（５）で表されるアシッドホスホキシ（メタ）アクリレート類がオートドープの抑制の点で好ましく用いられる。 The phosphoric acid esters used in the present invention are those in which all or part of the three hydrogen atoms possessed by phosphoric acid are substituted with organic groups, and various known compounds can be used. Acid phosphoxy (meth) acrylates represented by the general formula (5) are preferably used in terms of suppression of autodoping.
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
　上記一般式（５）中のＲ12は水素あるいはメチル基であり、Ｒ13は水素、メチル基、あるいは－ＣＨ2Ｃｌ基であり、Ｒ14は水素、炭素数１～１０のアルキル基、フェニル基、あるいは－ＮＨ3Ｃ2Ｈ4ＯＨ基であり、ｎは１～１０の正の整数であり、ｍ、ｌは１または２であり、ｍ＋ｌ＝３である。 In the general formula (5), R 12 is hydrogen or a methyl group, R 13 is hydrogen, a methyl group, or a —CH 2 Cl group, R 14 is hydrogen, an alkyl group having 1 to 10 carbon atoms, phenyl Or a —NH 3 C 2 H 4 OH group, n is a positive integer of 1 to 10, m and l are 1 or 2, and m + 1 = 3.
　かかる一般式（５）で表されるアシッドホスホキシ（メタ）アクリレート類の市販品としては、ユニケミカル社製のホスマーシリーズ、日本化薬社製のカヤマーシリーズ、共栄社油脂社製のライトエステルシリーズ、大八化学社製のＭＲシリーズ、ＡＲシリーズ、ＰＳシリーズ、新中村化学社製のＮＫエステルシリーズ、などを挙げることができる。 Commercially available products of the acid phosphoxy (meth) acrylates represented by the general formula (5) include the phosmer series manufactured by Unichemical Co., the Kayamar series manufactured by Nippon Kayaku Co., and the light ester manufactured by Kyoeisha Yushi Co., Ltd. Series, MR series manufactured by Daihachi Chemical Co., Ltd., AR series, PS series, NK ester series manufactured by Shin-Nakamura Chemical Co., Ltd., and the like.
　その具体例としてはＲ12がメチル基、Ｒ13が水素、Ｒ14が水素、ｎが１、ｍが１、ｌが２である化合物（例えば、ユニケミカル社製「ホスマーＭ」）や、Ｒ12がメチル基、Ｒ13が水素、Ｒ14が－ＮＨ3Ｃ2Ｈ4ＯＨ、ｎが１、ｍが１、ｌが２である化合物（例えば、ユニケミカル社製「ホスマーＭＨ」、Ｒ12がメチル基、Ｒ13が水素、Ｒ14が水素、ｎが４～５、ｍが１、ｌが２である化合物（例えば、ユニケミカル社製「ホスマーＰＥ」などを挙げることができる。
　中でも、本願発明で用いられるＰＶＡ系樹脂との親和性の観点から、一般式（５）において、Ｒ12がメチル基であるアシッドホスホキシメタクリレート類、Ｒ13が水素でありｎが５以下、特に１であるもの、Ｒ14が水素であるもの、およびｍが１、ｌが２であるものが好ましく用いられる。 Specific examples thereof include a compound in which R 12 is a methyl group, R 13 is hydrogen, R 14 is hydrogen, n is 1, m is 1 and l is 2 (for example, “Phosmer M” manufactured by Unichemical Co.), R 12 is a methyl group, R 13 is hydrogen, R 14 is —NH 3 C 2 H 4 OH, n is 1, m is 1, and l is 2 (for example, “Phosmer MH”, R 12 And a compound in which R 13 is hydrogen, R 14 is hydrogen, n is 4 to 5, m is 1, and l is 2 (for example, “Phosmer PE” manufactured by Unichemical Co., Ltd.).
Among them, the affinity of the viewpoint of the PVA-based resin used in the present invention, in the general formula (5), acid phosphoxy methacrylates R 12 is a methyl group, R 13 is hydrogen n is 5 or less, in particular what is 1, those wherein R 14 is hydrogen, and m is 1, l is preferably used is 2.
　本発明の不純物拡散用塗布液中の１５族元素化合物の含有量は、通常０．１～３０重量％であり、特に０．１～１０重量％、殊に０．１～５重量％の範囲が好ましく用いられる。
　また、１５族元素化合物のＰＶＡ系樹脂（Ａ）１００重量部に対する含有量は、通常１～３００重量部であり、特に２～２００重量部、殊に３～５０重量部の範囲が用いられる。
　かかる１５族元素化合物の含有量が小さいと、拡散層中の１５族元素（リン等）の含有量が小さくなり、充分な抵抗値が得られない場合がある。また、１５族元素化合物の含有量が多すぎると、ＰＶＡ系樹脂（Ａ）の溶解性が不充分となる場合がある。
　なお、かかる１５族元素化合物は、単一の化合物でもよく、二種以上のものを組合わせて用いてもよい。 The content of the group 15 element compound in the coating solution for impurity diffusion of the present invention is usually from 0.1 to 30% by weight, particularly from 0.1 to 10% by weight, particularly from 0.1 to 5% by weight. Is preferably used.
The content of the Group 15 element compound with respect to 100 parts by weight of the PVA resin (A) is usually 1 to 300 parts by weight, particularly 2 to 200 parts by weight, particularly 3 to 50 parts by weight.
When the content of the group 15 element compound is small, the content of the group 15 element (phosphorus or the like) in the diffusion layer is small, and a sufficient resistance value may not be obtained. Moreover, when there is too much content of 15 group element compound, the solubility of PVA-type resin (A) may become inadequate.
Such a Group 15 element compound may be a single compound or a combination of two or more.
　また、上記１３族元素化合物は、一般にＰ型半導体の製造において、不純物として用いられるものであり、ホウ素化合物やアルミニウム化合物を挙げることができるが、中でもホウ素化合物が好ましく用いられる。
　かかるホウ素化合物の具体例としては、ホウ酸、三酸化二ホウ素などのホウ酸類；ホウ酸アンモニウムなどのホウ酸塩類；三フッ化ホウ素、三塩化ホウ素、三臭化ホウ素、三ヨウ化ホウ素などのハロゲン化物；ホウ酸トリメチル、ホウ酸トリエチル、ホウ酸トリイソプロピルなどのホウ酸エステル類；窒化ホウ素などを挙げることができる。
　中でも、取り扱いの容易性の点で、ホウ酸や、ホウ酸塩類、ホウ酸エステル類、窒化ホウ素が好ましく用いられる。 The group 13 element compound is generally used as an impurity in the production of a P-type semiconductor, and examples thereof include boron compounds and aluminum compounds. Among these, boron compounds are preferably used.
Specific examples of such boron compounds include boric acids such as boric acid and diboron trioxide; borate salts such as ammonium borate; boron trifluoride, boron trichloride, boron tribromide, boron triiodide, etc. Halides; boric acid esters such as trimethyl borate, triethyl borate, triisopropyl borate; boron nitride, and the like.
Of these, boric acid, borates, borate esters, and boron nitride are preferably used from the viewpoint of easy handling.
　本発明において用いられるホウ酸エステル類とは、ホウ酸の持つ３つの水素の全部、あるいは一部が有機基で置換されたもので、公知の各種化合物を用いることが可能であるが、中でもホウ酸トリメチル、ホウ酸トリエチルが不純物拡散性の点で好ましく用いられる。 The boric acid esters used in the present invention are those in which all or part of the three hydrogen atoms of boric acid are substituted with organic groups, and various known compounds can be used. Trimethyl acid and triethyl borate are preferably used in terms of impurity diffusibility.
　本発明の不純物拡散用塗布液中の１３族元素化合物の含有量は、通常０．１～３０重量％であり、特に０．１～１０重量％、殊に０．１～５重量％の範囲が好ましく用いられる。
　また、１３族元素化合物のＰＶＡ系樹脂（Ａ）１００重量部に対する含有量は、通常１～３００重量部であり、特に３～２００重量部、殊に５～５０重量部の範囲が用いられる。
　かかる１３族元素化合物の含有量が小さいと、拡散層中の１３族元素（ホウ素等）の含有量が小さくなり、充分な抵抗値が得られない場合がある。また、１３族元素化合物の含有量が多すぎると、ＰＶＡ系樹脂（Ａ）の溶解性が不充分となる場合がある。 The content of the group 13 element compound in the coating solution for impurity diffusion of the present invention is usually from 0.1 to 30% by weight, particularly from 0.1 to 10% by weight, particularly from 0.1 to 5% by weight. Is preferably used.
The content of the group 13 element compound with respect to 100 parts by weight of the PVA resin (A) is usually 1 to 300 parts by weight, particularly 3 to 200 parts by weight, particularly 5 to 50 parts by weight.
When the content of the group 13 element compound is small, the content of the group 13 element (boron or the like) in the diffusion layer is small, and a sufficient resistance value may not be obtained. Moreover, when there is too much content of a group 13 element compound, the solubility of PVA-type resin (A) may become inadequate.
〔多価アルコール（Ｃ）〕
　本発明の不純物拡散用塗布液は、その溶剤の主成分として沸点が１００℃以上である多価アルコール（Ｃ）を用いることを特徴とするものである。
　かかる多価アルコール類（Ｃ）を主成分として用いることによって、塗布液の優れた粘度安定性が得られる。
　かかる多価アルコール（Ｃ）は、沸点が１００℃以上のものであるが、さらに１５０～４００℃、特に１７５～３００℃のものが好ましく用いられる。
　また、かかる多価アルコールとしては、脂肪族アルコール、芳香族アルコールのいずれも使用することができるが、ＰＶＡ系樹脂（Ａ）の溶解性の点から脂肪族アルコールが好ましい。 [Polyhydric alcohol (C)]
The impurity diffusion coating solution of the present invention is characterized in that a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher is used as the main component of the solvent.
By using such a polyhydric alcohol (C) as a main component, excellent viscosity stability of the coating solution can be obtained.
Such polyhydric alcohol (C) has a boiling point of 100 ° C. or higher, and more preferably 150 to 400 ° C., particularly 175 to 300 ° C.
As the polyhydric alcohol, either an aliphatic alcohol or an aromatic alcohol can be used, but an aliphatic alcohol is preferable from the viewpoint of the solubility of the PVA resin (A).
　かかる多価アルコール（Ｃ）としては、具体的には、エチレングリコール（１９７℃）、ジエチレングリコール（２４４℃）、トリエチレングリコール（２８７℃）、テトラエチレングリコール（３１４℃）、プロピレングリコール（１８８℃）などのニ価アルコール類；グリセリン（２９０℃）、トリメチロールプロパン（２９２℃）、ソルビトール（２９６℃）、マンニトール（２９０～２９５℃）、ペンタエリスリトール（２７６℃）、ポリグリセリンなどの三価以上の多価アルコール類、などを挙げることができる。なお、（　）内の値は沸点である。 Specific examples of the polyhydric alcohol (C) include ethylene glycol (197 ° C.), diethylene glycol (244 ° C.), triethylene glycol (287 ° C.), tetraethylene glycol (314 ° C.), and propylene glycol (188 ° C.). Trihydric alcohols such as glycerin (290 ° C.), trimethylolpropane (292 ° C.), sorbitol (296 ° C.), mannitol (290-295 ° C.), pentaerythritol (276 ° C.), polyglycerin and the like And polyhydric alcohols. The values in parentheses are boiling points.
　これらは単独で用いることも可能であるが、粘度の調整、ＰＶＡ系樹脂やリン化合物の溶解性、各種添加物の溶解性や分散性、基材への濡れ性などを調製するために、二種以上ものを併用して用いることが好ましい実施態様である。中でも、エチレングリコールとグリセリンの組み合わせが好ましく用いられ、その際のエチレングリコールとグリセリンの配合比率は所望する特性によって異なるが、通常、エチレングリコール／グリセリンの値が２０／８０～１００／０であり、さらに３０／７０～９０／１０、特に５０／５０～８０／２０の範囲から選択される。 These can be used alone, but in order to adjust the viscosity, the solubility of the PVA resin and phosphorus compound, the solubility and dispersibility of various additives, the wettability to the substrate, etc. It is a preferred embodiment to use more than one species in combination. Among them, a combination of ethylene glycol and glycerin is preferably used, and the blending ratio of ethylene glycol and glycerin varies depending on desired properties, but usually the value of ethylene glycol / glycerin is 20/80 to 100/0, Further, it is selected from the range of 30/70 to 90/10, particularly 50/50 to 80/20.
　また、多価アルコール以外の溶剤を併用することも可能であり、かかる溶剤としては、水、イソブチル酸－３－ヒドロキシ－２，２，４－トリメチルペンチルエステル（ＴＰＭ）や、メタノール、エタノール、イソプロパノールなどの低級アルコール系溶剤、メチルカルビトール、エチルカルビトール、ブチルカルビトールなどのカルビトール系溶剤、エチルセロソルブ、イソアミルセロソルブ、ヘキシルセロソルブなどのセロソルブ系溶剤、その他脂肪族炭化水素系溶剤、高級脂肪酸系溶剤、芳香族炭化水素系溶剤などを挙げることができる。
　かかる多価アルコール以外の溶剤の配合量は、通常、溶剤の全量に対して２０重量％以下であり、特に１０重量％以下である。 It is also possible to use a solvent other than the polyhydric alcohol, such as water, isobutyric acid-3-hydroxy-2,2,4-trimethylpentyl ester (TPM), methanol, ethanol, isopropanol. Lower alcohol solvents, such as methyl carbitol, ethyl carbitol, butyl carbitol, carbitol solvents, ethyl cellosolve, isoamyl cellosolve, cellosolve solvents such as hexyl cellosolve, other aliphatic hydrocarbon solvents, higher fatty acid solvents Examples include solvents and aromatic hydrocarbon solvents.
The amount of the solvent other than the polyhydric alcohol is usually 20% by weight or less, particularly 10% by weight or less, based on the total amount of the solvent.
　本発明の不純物拡散用塗布液における多価アルコール（Ｃ）の含有量は、７０重量％以上であり、さらに７０～９０重量％、特に７５～９０重量％の範囲が好ましく用いられる。
　かかる多価アルコール（Ｃ）の含有量が少なすぎると塗布液の粘度が高くなりすぎて、塗布作業性が低下したり、スクリーン印刷におけるスクリーンメッシュの目詰まりが起りやすくなる傾向がある。逆に多すぎると塗布液の粘度が低くなりすぎて塗膜が安定して形成されにくくなったり、乾燥に長時間を要する傾向があり、さらに拡散層中の不純物の含有量が少なくなりすぎる場合がある。 The content of the polyhydric alcohol (C) in the coating solution for impurity diffusion of the present invention is 70% by weight or more, more preferably 70 to 90% by weight, especially 75 to 90% by weight.
If the content of the polyhydric alcohol (C) is too small, the viscosity of the coating solution becomes too high, and the coating workability tends to be reduced, or the screen mesh tends to be clogged during screen printing. Conversely, if the amount is too large, the viscosity of the coating solution will be too low and the coating will be difficult to form stably, or it will take a long time to dry, and the content of impurities in the diffusion layer will be too low. There is.
〔界面活性剤（Ｄ）〕
　本発明の不純物拡散用塗布液には、半導体表面への濡れ性を向上させ、塗布液の発泡を抑制し、気泡に起因する印刷不良の防止などを目的として、界面活性剤（Ｄ）を配合することが好ましい。
　本発明の塗布液に用いられる界面活性剤としては、公知のノニオン系界面活性剤、カチオン系界面活性剤、アニオン系界面活性剤が挙げられ、いずれも使用することができるが、半導体への金属成分等の持込が少ないことから、ノニオン系界面活性剤が好ましい。
　かかるノニオン系界面活性剤としては、公知のものを使用することが可能であり、具体的にはエチレンオキサイド－プロピレンオキサイドのブロック共重合体、アセチレングリコール誘導体などの炭化水素系界面活性剤や、シリコン系界面活性剤、フッ素系界面活性剤や有機変性ポリシロキサンと特殊ポリマーの混合物などを挙げることができる。
　中でも、本発明の塗布液において発泡の抑制、および消泡性に優れている点で、炭化水素系界面活性剤、特にアセチレングリコール誘導体が好ましく用いられる。 [Surfactant (D)]
In order to improve the wettability to the semiconductor surface, suppress foaming of the coating solution, and prevent printing defects caused by bubbles, the impurity diffusion coating solution of the present invention is blended with a surfactant (D). It is preferable to do.
Examples of the surfactant used in the coating solution of the present invention include known nonionic surfactants, cationic surfactants, and anionic surfactants. Nonionic surfactants are preferred because they bring less components and the like.
As such nonionic surfactants, known ones can be used. Specifically, hydrocarbon surfactants such as block copolymers of ethylene oxide-propylene oxide, acetylene glycol derivatives, silicon And surfactants, fluorine surfactants, and mixtures of organically modified polysiloxanes and special polymers.
Of these, hydrocarbon surfactants, particularly acetylene glycol derivatives, are preferably used because they are excellent in suppressing foaming and defoaming in the coating solution of the present invention.
　かかるアセチレングリコール誘導体としては、下記式（６）で表されるものが好ましく用いられる。 As such acetylene glycol derivatives, those represented by the following formula (6) are preferably used.
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
　上記一般式（６）中のＲ15，Ｒ18はそれぞれ独立して炭素数１～２０のアルキル基を示し、特に炭素数１～５のものが好ましく、殊に炭素数３～５のものが好ましく用いられる。また、Ｒ16，Ｒ17はそれぞれ独立して炭素数１～３のアルキル基を示し、特にメチル基が好ましく用いられる。なお、Ｒ15とＲ18、およびＲ16とＲ17はそれぞれ同一でも異なったものでもよいが、それぞれ同一構造のものが好ましく用いられる。
　また、ｓ，ｔはそれぞれ０～３０の整数であり、さらにｓ＋ｔが１～１０、特に１～５、殊に１～３であるものが好ましく用いられる。 In the above general formula (6), R 15 and R 18 each independently represents an alkyl group having 1 to 20 carbon atoms, preferably having 1 to 5 carbon atoms, particularly preferably having 3 to 5 carbon atoms. Preferably used. R 16 and R 17 each independently represents an alkyl group having 1 to 3 carbon atoms, and a methyl group is particularly preferably used. R 15 and R 18 and R 16 and R 17 may be the same or different, but those having the same structure are preferably used.
Further, s and t are each an integer of 0 to 30, and those in which s + t is 1 to 10, particularly 1 to 5, particularly 1 to 3 are preferably used.
　かかるアセチレングリコール誘導体としては、具体的に、２，５，８，１１－テトラメチル－６－ドデシン－５，８－ジオールのエチレンオキサイド付加物、５，８－ジメチル－６－ドデシン－５，８－ジオールのエチレンオキサイド付加物、２，４，７，９－テトラメチル－５－デシン－４，７ジオールのエチレンオキサイド付加物、４，７－ジメチル－５－デシン－４，７－ジオールのエチレンオキサイド付加物、２，３，６，７－テトラメチル－４－オクチン－３，６－ジオールのエチレンオキサイド付加物、３，６－ジメチル－４－オクチン－３，６－ジオールのエチレンオキサイド付加物、２，５－ジメチル－３－ヘキシン―２，５－ジオールのエチレンオキサイド付加物などを挙げることができる。
　これらの中でも、２，４，７，９－テトラメチル－５－デシン－４，７ジオールのエチレンオキサイド付加物であって、エチレンオキサイドの付加量（ｍ＋ｎ）が１～２であるものが好ましく用いられる。 Specific examples of such acetylene glycol derivatives include 2,5,8,11-tetramethyl-6-dodecin-5,8-diol ethylene oxide adduct, 5,8-dimethyl-6-dodecin-5,8. -Ethylene oxide adduct of diol, ethylene oxide adduct of 2,4,7,9-tetramethyl-5-decyne-4,7 diol, ethylene of 4,7-dimethyl-5-decyne-4,7-diol Oxide adduct, ethylene oxide adduct of 2,3,6,7-tetramethyl-4-octyne-3,6-diol, ethylene oxide adduct of 3,6-dimethyl-4-octyne-3,6-diol And ethylene oxide adduct of 2,5-dimethyl-3-hexyne-2,5-diol.
Of these, ethylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7 diol having an ethylene oxide addition amount (m + n) of 1 to 2 are preferably used. It is done.
　かかるアセチレングリコール誘導体である界面活性剤の市販品としては、日信化学工業社製のサーフィノールシリーズなどを挙げることができる。 Examples of such commercially available surfactants that are acetylene glycol derivatives include Surfynol series manufactured by Nissin Chemical Industry Co., Ltd.
　本発明の不純物拡散用塗布液に配合される界面活性剤（Ｄ）の配合量は、通常、塗布液中０．１～１０重量％であり、特に０．３～８重量％、殊に０．５～５重量％の範囲が好ましく用いられる。かかる界面活性剤（Ｄ）の配合量が少なすぎると、抑泡・消泡効果が不充分である場合があり、逆に多すぎると液から分離して均一溶液が得られなくなる場合がある。 The amount of the surfactant (D) blended in the coating solution for impurity diffusion of the present invention is usually 0.1 to 10% by weight in the coating solution, particularly 0.3 to 8% by weight, especially 0. The range of 5 to 5% by weight is preferably used. If the blending amount of the surfactant (D) is too small, the effect of suppressing foam and defoaming may be insufficient. Conversely, if the amount is too large, it may be separated from the liquid and a uniform solution may not be obtained.
〔無機微粒子（Ｅ）〕
　本発明の不純物拡散用塗布液には、スクリーン印刷特性を改善する目的で、各種の無機微粒子（Ｅ）を配合することが可能である。
　かかる無機微粒子（Ｅ）としては、コロイダルシリカ、非晶質シリカ、フュームドシリカなどのシリカ類が好適であり、中でもコロイダルシリカが好ましく用いられる。
　かかる無機微粒子（Ｅ）の配合量は、通常、塗布液中０．５～２０重量％であり、特に１～１０重量％の範囲が好ましく用いられる。 [Inorganic fine particles (E)]
Various inorganic fine particles (E) can be blended in the impurity diffusion coating solution of the present invention for the purpose of improving screen printing characteristics.
As the inorganic fine particles (E), silicas such as colloidal silica, amorphous silica, and fumed silica are suitable, and among them, colloidal silica is preferably used.
The amount of such inorganic fine particles (E) is usually 0.5 to 20% by weight in the coating solution, and particularly preferably in the range of 1 to 10% by weight.
〔不純物拡散用塗布液〕
　本発明の不純物拡散用塗布液は、上述のＰＶＡ系樹脂（Ａ）、不純物（Ｂ）、および沸点が１００℃以上の多価アルコール（Ｃ）を含有し、該多価アルコール（Ｃ）の含有量が塗布液中の７０重量％であるものであって、必要に応じて、さらに界面活性剤（Ｄ）、および無機微粒子（Ｅ）、およびその他の添加剤を含有するものである。
　かかる不純物拡散用塗布液の２０℃における粘度は通常３００～１００，０００ｍＰａ・ｓであり、特に５００～１０，０００ｍＰａ・ｓ、殊に７００～６，０００ｍＰａ・ｓの範囲が好ましく用いられる。なお、かかる粘度はＢ型粘度計を用いた測定したものである。
　かかる塗布液の濃度、および粘度が小さすぎると塗膜が安定して形成されにくくなったり、拡散層中の不純物の含有量が不十分になる場合があり、逆に濃度、および粘度が大きすぎると、塗布作業性が低下したり、スクリーン印刷におけるスクリーンメッシュの目詰まりが起りやすくなる傾向がある。 [Impurity coating solution]
The coating solution for diffusion of impurities of the present invention contains the above-described PVA resin (A), impurities (B), and polyhydric alcohol (C) having a boiling point of 100 ° C. or higher, and contains the polyhydric alcohol (C). The amount is 70% by weight in the coating solution, and further contains a surfactant (D), inorganic fine particles (E), and other additives as necessary.
The viscosity at 20 ° C. of such an impurity diffusion coating solution is usually 300 to 100,000 mPa · s, preferably 500 to 10,000 mPa · s, particularly 700 to 6,000 mPa · s. In addition, this viscosity is measured using a B-type viscometer.
If the concentration and viscosity of the coating solution are too small, the coating film may not be stably formed or the content of impurities in the diffusion layer may be insufficient. Conversely, the concentration and viscosity are too large. Then, there is a tendency that the coating workability is deteriorated or the screen mesh is easily clogged in the screen printing.
　本発明の不純物拡散用塗布液の調製法は特に限定されないが、例えば、上述のＰＶＡ系樹脂（Ａ）と不純物（Ｂ）を逐次、あるいは同時に多価アルコール（Ｃ）に溶解する方法、ＰＶＡ系樹脂（Ａ）、および不純物（Ｂ）の多価アルコール（Ｃ）溶液を別々に調製し、それらを混合する方法などが挙げられ、かかる溶解、調製の際には、加熱、撹拌しながら行うことが好ましい。
　また、界面活性剤（Ｄ）、無機微粒子（Ｅ）、その他の添加剤については、上記塗布液の調製後に配合、あるいは上記調製の過程で配合、のいずれの方法も採用することができる。 The method for preparing the impurity diffusion coating solution of the present invention is not particularly limited. For example, a method in which the above-described PVA resin (A) and impurity (B) are dissolved in polyhydric alcohol (C) sequentially or simultaneously, PVA system A method of separately preparing a resin (A) and a polyhydric alcohol (C) solution of impurities (B) and mixing them, and the like, such dissolution, preparation, while heating and stirring Is preferred.
As for the surfactant (D), the inorganic fine particles (E), and other additives, any method of blending after the preparation of the coating liquid or blending in the course of the preparation can be employed.
　かくして得られた本発明の不純物拡散用塗布液は保存安定性に優れるので、大量に調製して保管したり、小分けにして移動したりすることができ、また、途中まで使用して残りを保存することも可能である。 The impurity diffusion coating solution of the present invention thus obtained is excellent in storage stability, so it can be prepared and stored in large quantities, moved in small portions, or used halfway to store the rest. It is also possible to do.
〔半導体〕
　次に、本発明の不純物拡散用塗布液を用いて得られる半導体について説明する。
　かかる半導体は、シリコンやゲルマニウムなどの半導体基板上に本発明の不純物拡散用塗布液を塗布し、乾燥、焼成、拡散の各工程を経て、半導体基板中に不純物の拡散層を形成することで製造される。 〔semiconductor〕
Next, a semiconductor obtained using the impurity diffusion coating solution of the present invention will be described.
Such a semiconductor is manufactured by applying the impurity diffusion coating solution of the present invention on a semiconductor substrate such as silicon or germanium, and forming an impurity diffusion layer in the semiconductor substrate through drying, baking, and diffusion steps. Is done.
　半導体基板上に不純物拡散用塗布液を塗布する方法としては、公知の方法を用いることが可能で、具体的には、スクリーン印刷法、グラビア印刷法、凸版印刷法、平板印刷法、スピンコーター法、コンマコーター法、ダイヘッドコーター法、ダイリップコーター法、などを挙げることができる。中でも、本発明の塗布液はスクリーン印刷法に用いることで最大の効果が得られ、４インチ以上の大型ウェハーに対しても均一な塗布膜を得ることができる。
　半導体基板上への塗布液の塗布量は、基板の種類や半導体の用途、塗布液中の不純物化合物の含有量と所望の不純物含有量によって異なるが、通常、１～１００ｇ／ｍ2であり、特に１～５０ｇ／ｍ2の範囲で実施される。 As a method for applying the impurity diffusion coating solution on the semiconductor substrate, a known method can be used. Specifically, a screen printing method, a gravure printing method, a relief printing method, a lithographic printing method, a spin coater method. , Comma coater method, die head coater method, die lip coater method, and the like. Among these, the coating solution of the present invention is most effective when used in a screen printing method, and a uniform coating film can be obtained even for large wafers of 4 inches or more.
The coating amount of the coating solution on the semiconductor substrate varies depending on the type of the substrate, the use of the semiconductor, the content of the impurity compound in the coating solution and the desired impurity content, but is usually 1 to 100 g / m 2 . In particular, it is carried out in the range of 1 to 50 g / m 2 .
　続く乾燥工程にて塗布膜から水等の揮発成分が除去され、その条件としては、適宜設定すればよいが、通常、２０～３００℃、特に１００～２００℃での温度条件下、１～６０分、特に５～３０分の乾燥時間が用いられる。乾燥方法についても特に限定されず、熱風乾燥、赤外線加熱乾燥、真空乾燥、などの公知の方法を用いることができる。
　なお、必要に応じて塗布工程と乾燥工程を連続して実施することも可能である。 In the subsequent drying step, volatile components such as water are removed from the coating film, and the conditions may be set as appropriate. Usually, the temperature is 20 to 300 ° C., particularly 100 to 200 ° C. Minutes, in particular 5 to 30 minutes, are used. The drying method is not particularly limited, and a known method such as hot air drying, infrared heat drying, or vacuum drying can be used.
In addition, it is also possible to implement an application | coating process and a drying process continuously as needed.
　続く焼成工程（脱脂工程）では、電気炉等を用い、塗布膜中の有機成分の大半が除去される。かかる工程の条件は、塗布液の組成や塗布膜の厚さによって適宜調節する必要があるが、通常、３００～１０００℃、特に４００～８００℃の温度条件、１～１２０分、特に５～６０分の時間で実施される。
　さらに、拡散工程で半導体基板中に不純物が拡散され、拡散層が形成されるが、焼成工程と同様に電気炉等を用い、８００～１４００℃の温度条件下、枚葉、あるいは複数枚を重ね合わせた状態で行われる。
　なお、焼成工程と拡散工程を一工程で実施する、あるいは、焼成工程にて拡散が進行し、所望とする抵抗値が得られる場合、拡散工程を省略することも可能である。 In the subsequent firing step (degreasing step), most of the organic components in the coating film are removed using an electric furnace or the like. The conditions of such a process need to be adjusted as appropriate depending on the composition of the coating solution and the thickness of the coating film, but are usually 300 to 1000 ° C., particularly 400 to 800 ° C., 1 to 120 minutes, particularly 5 to 60. Implemented in minutes.
Furthermore, impurities are diffused in the semiconductor substrate in the diffusion process, and a diffusion layer is formed. In the same manner as in the baking process, an electric furnace or the like is used, and a single wafer or a plurality of sheets are stacked under a temperature condition of 800 to 1400 ° C. Performed in a combined state.
Note that it is possible to omit the diffusion step when the firing step and the diffusion step are performed in one step, or when diffusion proceeds in the baking step and a desired resistance value is obtained.
　かかる半導体の表面抵抗は、不純物の含有量や拡散温度、拡散時間などによって制御することができ、通常、０．０３～１００００Ω／□の範囲で、目的とする用途に適した表面抵抗のものを得ることが可能である。 The surface resistance of such semiconductors can be controlled by the impurity content, diffusion temperature, diffusion time, etc., and usually has a surface resistance in the range of 0.03 to 10000 Ω / □ suitable for the intended use. It is possible to obtain.
　以下に、本発明を実施例を挙げて説明するが、本発明はその要旨を超えない限り、実施例の記載に限定されるものではない。
　尚、例中、「部」、「％」とあるのは、断りのない限り重量基準を意味する。 Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to the description of the examples unless it exceeds the gist.
In the examples, “parts” and “%” mean weight basis unless otherwise specified.
製造例１
〔ＰＶＡ系樹脂（Ａ１）の製造〕
　還流冷却器、滴下漏斗、撹拌機を備えた反応容器に、酢酸ビニル１５００部、メタノール６４８部、アゾビスイソブチロニトリルを０．３３モル％（対仕込み酢酸ビニル）投入し、撹拌しながら窒素気流下で温度を上昇させ、６０℃で重合を開始した。酢酸ビニルの重合率が９０％となった時点で、ｍ－ジニトロベンゼンを添加して重合を終了し、続いて、メタノール蒸気を吹き込む方法により未反応の酢酸ビニルモノマーを系外に除去し共重合体のメタノール溶液とした。 Production Example 1
[Production of PVA resin (A1)]
Into a reaction vessel equipped with a reflux condenser, a dropping funnel, and a stirrer, 1500 parts of vinyl acetate, 648 parts of methanol, and 0.33 mol% of azobisisobutyronitrile (compared with vinyl acetate) were charged, and nitrogen was stirred. The temperature was raised under an air stream, and polymerization was started at 60 ° C. When the polymerization rate of vinyl acetate reaches 90%, m-dinitrobenzene is added to complete the polymerization, and then unreacted vinyl acetate monomer is removed from the system by blowing methanol vapor. A combined methanol solution was obtained.
　ついで、上記メタノール溶液をさらにメタノールで希釈し、濃度３０％に調整してニーダーに仕込み、溶液温度を３５℃に保ちながら、水酸化ナトリウムの２％メタノール溶液を共重合体中の酢酸ビニル構造単位の１モルに対してＮａ量として３．４ミリモルとなる割合で加えてケン化を行った。ケン化が進行するとともにケン化物が析出し、粒子状となった時点で濾別し、メタノールでよく洗浄して熱風乾燥機中で乾燥し、目的とするＰＶＡ系樹脂（Ａ１）を作製した。 Next, the methanol solution was further diluted with methanol, adjusted to a concentration of 30%, charged into a kneader, and a 2% methanol solution of sodium hydroxide was added to the vinyl acetate structural unit in the copolymer while maintaining the solution temperature at 35 ° C. The saponification was carried out by adding Na at a ratio of 3.4 mmol as 1 mol. As saponification progressed, when saponified substances were precipitated and formed into particles, they were separated by filtration, washed well with methanol, and dried in a hot air drier to prepare the intended PVA resin (A1).
　得られたＰＶＡ系樹脂（Ａ１）のケン化度は、残存酢酸ビニルの加水分解に要するアルカリ消費量にて分析したところ、７８．０モル％であった。また、平均重合度は、ＪＩＳ　Ｋ　６７２６に準じて分析を行ったところ、１４００であった。（表１） The saponification degree of the obtained PVA resin (A1) was 78.0 mol% when analyzed by the alkali consumption required for hydrolysis of the residual vinyl acetate. The average degree of polymerization was 1400 as analyzed according to JIS K 6726. (Table 1)
製造例２
〔ＰＶＡ系樹脂（Ａ２）の製造〕
　還流冷却器、滴下漏斗、撹拌機を備えた反応容器に、酢酸ビニル１０００部、メタノール７００部、３，４－ジアセトキシ－１－ブテン８８部を仕込み、アゾビスイソブチロニトリルを１．５モル％（対仕込み酢酸ビニル）投入し、撹拌しながら窒素気流下で温度を上昇させ（約６０℃）、重合を開始した。重合開始と同時にＨＡＮＮＡ法により、３，４－ジアセトキシ－１－ブテン３１部とメタノール１２２．３部の混合液を滴下し、途中、２時間目と４時間目の時点でアゾビスイソブチロニトリルをそれぞれ０．５モル％（対仕込み酢酸ビニル）追加した。重合開始から９時間目の、酢酸ビニルの重合率が９３．９％となった時点で、ｍ－ジニトロベンゼンを添加して重合を終了し、続いて、メタノール蒸気を吹き込む方法により未反応の酢酸ビニルモノマーを系外に除去し共重合体のメタノール溶液とした。 Production Example 2
[Production of PVA resin (A2)]
A reaction vessel equipped with a reflux condenser, a dropping funnel and a stirrer was charged with 1000 parts of vinyl acetate, 700 parts of methanol, and 88 parts of 3,4-diacetoxy-1-butene, and 1.5 mol of azobisisobutyronitrile. % (Vs. vinyl acetate charged) was added, the temperature was raised under a nitrogen stream with stirring (about 60 ° C.), and polymerization was started. Simultaneously with the start of the polymerization, a mixed solution of 31 parts of 3,4-diacetoxy-1-butene and 122.3 parts of methanol was dropped by the HANNA method, and azobisisobutyronitrile was added at the second and fourth hours. Was added in an amount of 0.5 mol% (vs. vinyl acetate charged). Nine hours after the start of polymerization, when the polymerization rate of vinyl acetate reaches 93.9%, m-dinitrobenzene is added to complete the polymerization, and then unreacted acetic acid is produced by blowing methanol vapor. The vinyl monomer was removed from the system to obtain a methanol solution of the copolymer.
　ついで、上記メタノール溶液をさらにメタノールで希釈し、濃度３０％に調整してニーダーに仕込み、溶液温度を３５℃に保ちながら、水酸化ナトリウムの２％メタノール溶液を共重合体中の酢酸ビニル構造単位および３，４－ジアセトキシ－１－ブテン構造単位の合計量１モルに対してＮａ量として３．４ミリモルとなる割合で加えてケン化を行った。ケン化が進行するとともにケン化物が析出し、粒子状となった時点で濾別し、メタノールでよく洗浄して熱風乾燥機中で乾燥し、目的とするＰＶＡ系樹脂（Ａ２）を作製した。 Next, the methanol solution was further diluted with methanol, adjusted to a concentration of 30%, charged into a kneader, and a 2% methanol solution of sodium hydroxide was added to the vinyl acetate structural unit in the copolymer while maintaining the solution temperature at 35 ° C. Further, saponification was carried out by adding Na in an amount of 3.4 mmol with respect to 1 mol of the total amount of 3,4-diacetoxy-1-butene structural units. As saponification progressed, when saponified substances were precipitated and formed into particles, they were separated by filtration, washed well with methanol, and dried in a hot air dryer to prepare the intended PVA resin (A2).
　得られたＰＶＡ系樹脂（Ａ２）のケン化度は、残存酢酸ビニルおよび３，４－ジアセトキシ－１－ブテンの加水分解に要するアルカリ消費量にて分析したところ、７９．７モル％であった。また、平均重合度は、ＪＩＳ　Ｋ　６７２６に準じて分析を行ったところ、４５０であった。また、一般式（１）で表される１，２－ジオール構造単位の含有量は、1Ｈ－ＮＭＲ（３００ＭＨｚプロトンＮＭＲ、ｄ６－ＤＭＳＯ溶液、内部標準物質；テトラメチルシラン、５０℃）にて測定した積分値より算出したところ、６モル％であった。（表１） The degree of saponification of the obtained PVA resin (A2) was 79.7 mol% when analyzed by the alkali consumption required for hydrolysis of residual vinyl acetate and 3,4-diacetoxy-1-butene. . The average degree of polymerization was 450 when analyzed according to JIS K 6726. The content of the 1,2-diol structural unit represented by the general formula (1) is 1 H-NMR (300 MHz proton NMR, d6-DMSO solution, internal standard substance: tetramethylsilane, 50 ° C.). It was 6 mol% when computed from the measured integral value. (Table 1)
実施例１
＜リン拡散用塗布液の作製＞
　エチレングリコール（Ｃ）８５部に、ケン化度７８．０モル％、平均重合度１４００である未変性ＰＶＡ系樹脂（Ａ１）１０部を加え、加熱撹拌しながら溶解した。そこに、不純物（Ｂ）として五酸化二リン（Ｂ２）３部を配合し、界面活性剤（Ｄ）として、一般式（６）において、Ｒ15、Ｒ18が２－メチルプロピル基、Ｒ16、Ｒ17がメチル基、ｓ＋ｔ≒１．３である２，４，７，９－テトラメチル－５－デシン－４，７－ジオールのエチレンオキサイド付加物（日信化学工業社製「サーフィノール４２０」）（Ｄ１）２部を配合して、リン拡散用塗布液を作製した。 Example 1
<Preparation of coating solution for phosphorus diffusion>
To 85 parts of ethylene glycol (C), 10 parts of an unmodified PVA resin (A1) having a saponification degree of 78.0 mol% and an average polymerization degree of 1400 was added and dissolved while heating and stirring. Thereto, 3 parts of diphosphorus pentoxide (B2) is blended as an impurity (B), and R 15 and R 18 in the general formula (6) are 2-methylpropyl groups, R 16 as the surfactant (D). , R 17 is a methyl group, s + t≈1.3, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethylene oxide adduct (“Surfinol 420 manufactured by Nissin Chemical Industry Co., Ltd.) ]) (D1) 2 parts were blended to prepare a phosphorus diffusion coating solution.
＜半導体基板への塗布、印刷性評価＞
　上記作製のリン拡散用塗布液を用い、Ｐ型半導体基板（多結晶シリコン、１５６ｍｍ角、２００μｍ厚）に、下記の印刷条件にてスクリーン印刷を行い、スクレッパーで塗布液を供給した状態で一定時間（３０、６０分）放置した後、再度印刷を行った。
　得られた印刷面の状態を目視観察し、下記の評価条件にて印刷性を評価した。結果を表３に示す。
（印刷条件）
　　印刷機　　　　　：ニューロング精密工業社製「ＬＳ－３４ＧＸ」
　　　スキージー　　：ニューロング精密工業社製ＮＭスキージー（硬度：６０）
　　　スキージー角　：８０度
　　　スクレッパー　：ニューロング精密工業社製ＮＭスキージー（硬度：６０）
　　　スクレッパー角：８６度
　　　印圧　　　　　：０．２ＭＰａ
　　スクリーン版　　：東京プロセスサービス社製
　　　版サイズ　　　：４５０ｍｍ角
　　　メッシュ種　　：Ｖ３３０
　　　乳剤種　　　　：ＴＮ－１
　　　乳剤厚　　　　：１０μｍ
　　　パターン　　　：Ｌ／Ｓ＝８０～２２０μｍ、２０μｍ毎／Ｌ×３
　　　　　　　　　　　３０ｍｍ角のベタパターンが２箇所
　　印刷環境　　　　：２３℃、６０％ＲＨ
（評価条件）
　　○：全パターンが印刷されていた。
　　△：印刷された全パターンの一部にかすれが認められた。
　　×：パターンに一部、明らかな欠けが認められた。 <Application to semiconductor substrate, printability evaluation>
Using the phosphorus diffusion coating solution prepared above, screen printing was performed on a P-type semiconductor substrate (polycrystalline silicon, 156 mm square, 200 μm thickness) under the following printing conditions, and the coating solution was supplied with a scraper for a certain period of time. (30, 60 minutes) After leaving, printing was performed again.
The state of the obtained printed surface was visually observed, and the printability was evaluated under the following evaluation conditions. The results are shown in Table 3.
(Printing conditions)
Printing machine: “LS-34GX” manufactured by Neurong Seimitsu Kogyo Co., Ltd.
Squeegee: NM squeegee (Hardness: 60) manufactured by Neurong Seimitsu Kogyo Co., Ltd.
Squeegee angle: 80 degrees Scraper: NM squeegee manufactured by Neurong Seimitsu Kogyo Co., Ltd. (hardness: 60)
Scraper angle: 86 degrees Printing pressure: 0.2 MPa
Screen version: manufactured by Tokyo Process Service Co., Ltd. Plate size: 450 mm square Mesh type: V330
Emulsion type: TN-1
Emulsion thickness: 10 μm
Pattern: L / S = 80 to 220 μm, every 20 μm / L × 3
Two 30mm square solid patterns Printing environment: 23 ° C, 60% RH
(Evaluation conditions)
○: All patterns were printed.
Δ: Fading was observed in a part of all printed patterns.
X: Some clear chipping was recognized in the pattern.
＜半導体の作製、表面抵抗測定＞
　上記作製のリン拡散用塗布液を用い、上記と同様の印刷条件にて、１５０ｍｍ角のベタパターンでスクリーン印刷された半導体基板を、熱風循環乾燥機中１５０℃で２分間乾燥した。その後、温度：８５０℃、ガス種：窒素＋酸素（４％）、ガス流量：５０Ｌ／分のチューブ炉に半導体基板を直立した状態で投入し、１５分間ホールド後、取り出し、４６％フッ化水素水溶液中で揺動させながら洗浄した。このようにして、半導体基板中にリンの拡散層を有する半導体を得た。
　得られた半導体の拡散層の上部（焼成時のように半導体を直立状態にした際の、拡散層の上から３０ｍｍの部分）、および下部（焼成時のように半導体を直立状態にした際の、拡散層の下から３０ｍｍの部分）の表面抵抗値を、抵抗測定器（三菱アナリテック社製「ロレスター」、ＰＳＰプローブ使用）を用いて測定した。結果を表３に示す。 <Semiconductor fabrication, surface resistance measurement>
A semiconductor substrate screen-printed with a solid pattern of 150 mm square was dried at 150 ° C. for 2 minutes in a hot air circulating drier under the same printing conditions as described above using the phosphorus diffusion coating solution prepared above. Thereafter, the semiconductor substrate was put upright in a tube furnace at a temperature of 850 ° C., a gas type: nitrogen + oxygen (4%), and a gas flow rate: 50 L / min, held for 15 minutes, taken out, and 46% hydrogen fluoride. Washing was performed while rocking in an aqueous solution. Thus, a semiconductor having a phosphorus diffusion layer in the semiconductor substrate was obtained.
The upper part of the obtained semiconductor diffusion layer (the part 30 mm from the top of the diffusion layer when the semiconductor is in an upright state during firing) and the lower part (when the semiconductor is in an upright state as during firing) The surface resistance value of a portion 30 mm from the bottom of the diffusion layer) was measured using a resistance measuring instrument (“Lorestar” manufactured by Mitsubishi Analytech Co., Ltd., using a PSP probe). The results are shown in Table 3.
実施例２
　実施例１において、不純物（Ｂ）としてリン酸エステル（一般式（５）においてＲ12がメチル基、Ｒ13が水素、Ｒ14が水素、ｎが１、ｍが１、ｌが２であるアシッドホスホキシメタアクリレート（ユニケミカル社製「ホスマーＭ」））（Ｂ１）７部を用い、多価アルコール（Ｃ）としてエチレングリコールとグリセリンの混合物を使用し、界面活性剤（Ｄ）としてアミノアルコキシシランを主成分とする化合物（東レ・ダウコーニング社製「ＳＨ－２１」）（Ｄ２）を用い、各成分の配合量を表２に示すとおりとした。それ以外は実施例１と同様にしてリン拡散用塗布液を作製し、同様に評価した。評価結果を表３に示す。 Example 2
In Example 1, as the impurity (B), a phosphoric acid ester (acid in which R 12 is a methyl group, R 13 is hydrogen, R 14 is hydrogen, n is 1, m is 1, and l is 2 in the general formula (5) Phosoxymethacrylate ("Phosmer M" manufactured by Unichemical Co., Ltd.)) (B1) 7 parts, a mixture of ethylene glycol and glycerin as polyhydric alcohol (C), and aminoalkoxysilane as surfactant (D) The main component (“SH-21” manufactured by Toray Dow Corning Co., Ltd.) (D2) was used, and the amount of each component was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
実施例３
　実施例１において、多価アルコール（Ｃ）としてエチレングリコールとグリセリンの混合物を使用し、さらに無機微粒子（Ｅ）として水８０ｗｔ％に２０ｗｔ％のコロイダルシリカが分散されているコロイダルシリカ溶液（フジミコーポレーション社製「ＰＬＡＮＥＲＬＩＴＥ　４１０１」）１０部を配合し、各成分の配合量を表２に示すとおりとした。それ以外は実施例１と同様にしてリン拡散用塗布液を作製し、同様に評価した。評価結果を表３に示す。 Example 3
In Example 1, a mixture of ethylene glycol and glycerin is used as polyhydric alcohol (C), and colloidal silica solution in which 20 wt% colloidal silica is dispersed in 80 wt% water as inorganic fine particles (E) (Fujimi Corporation) 10 parts of “PLANERLITE 4101” manufactured by the manufacturer were blended, and the blending amount of each component was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
実施例４
　実施例２において、ＰＶＡ系樹脂（Ａ）として製造例２で得られたＰＶＡ系樹脂（Ａ２）を用い、多価アルコール（Ｃ）としてエチレングリコールとグリセリンの混合物を使用し、界面活性剤（Ｄ）を配合せず、各成分の配合量を表２に示すとおりとした。それ以外は実施例１と同様にしてリン拡散用塗布液を作製し、同様に評価した。評価結果を表３に示す。 Example 4
In Example 2, the PVA resin (A2) obtained in Production Example 2 was used as the PVA resin (A), a mixture of ethylene glycol and glycerin was used as the polyhydric alcohol (C), and the surfactant (D ), And the amount of each component was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
実施例５
　実施例４において、界面活性剤（Ｄ）として有機変性ポリシロキサンと特殊ポリマーの混合物を含有する水系エマルジョン（共栄社化学社製「アクアレンＳＢ－６３０」（Ｄ３）を用い、各成分の配合量を表２に示すとおりとした。それ以外は実施例４と同様にしてリン拡散用塗布液を作製し、同様に評価した。評価結果を表３に示す。 Example 5
In Example 4, a water-based emulsion (“Aqualene SB-630” (D3) manufactured by Kyoeisha Chemical Co., Ltd.) containing a mixture of an organically modified polysiloxane and a special polymer was used as the surfactant (D). Other than that, a phosphorus diffusion coating solution was prepared and evaluated in the same manner as in Example 4. Table 3 shows the evaluation results.
実施例６
　実施例１において、不純物（Ｂ）としてホウ酸（Ｂ３）２部を用い、エチレングリコール（Ｃ１）を８６部とした。それ以外は実施例１と同様にして不純物拡散用塗布液を作製した。
　得られた塗布液を用い、半導体基板としてＮ型半導体基板を用いた以外は実施例１と同様に半導体基板にスクリーン印刷を行い、印刷性評価を行った。また、上記塗布液を用い、以下の基準に従い半導体の作製、表面抵抗測定を行った。結果を表３に示す。 Example 6
In Example 1, 2 parts of boric acid (B3) was used as the impurity (B), and 86 parts of ethylene glycol (C1) was used. Otherwise, an impurity diffusion coating solution was prepared in the same manner as in Example 1.
Using the obtained coating liquid, screen printing was performed on the semiconductor substrate in the same manner as in Example 1 except that an N-type semiconductor substrate was used as the semiconductor substrate, and printability was evaluated. Further, using the above coating solution, semiconductor fabrication and surface resistance measurement were performed according to the following criteria. The results are shown in Table 3.
＜半導体の作製、表面抵抗測定＞
　得られた不純物拡散用塗布液を用い、上記と同様の印刷条件にて、１５０ｍｍ角のベタパターンでスクリーン印刷された半導体基板を、熱風循環乾燥機中１５０℃で２分間乾燥した。その後、温度：９５０℃、ガス種：窒素、ガス流量：５０Ｌ／分のチューブ炉に半導体基板を直立した状態で投入し、１５分間ホールド後、窒素を止め、酸素を同流量で１５分流した。ついで、基板を取り出し、４６％フッ化水素水溶液中で揺動させながら洗浄し、半導体基板中にホウ素の拡散層を有する半導体を得て、その拡散層の上部および下部の表面抵抗値を、実施例１と同様に測定した。結果を表３に示す。 <Semiconductor fabrication, surface resistance measurement>
Using the obtained impurity diffusion coating solution, a semiconductor substrate screen-printed with a solid pattern of 150 mm square under the same printing conditions as above was dried at 150 ° C. for 2 minutes in a hot air circulating dryer. Thereafter, the semiconductor substrate was put upright in a tube furnace at a temperature of 950 ° C., a gas type of nitrogen, and a gas flow rate of 50 L / min. After holding for 15 minutes, the nitrogen was stopped and oxygen was allowed to flow at the same flow rate for 15 minutes. Next, the substrate is taken out and washed while being swung in a 46% hydrogen fluoride aqueous solution to obtain a semiconductor having a boron diffusion layer in the semiconductor substrate, and the surface resistance values at the upper and lower portions of the diffusion layer are measured. Measurement was performed in the same manner as in Example 1. The results are shown in Table 3.
実施例７
　実施例２において、不純物（Ｂ）としてホウ酸トリエチル（Ｂ４）７部を用いた以外は実施例２と同様にして不純物拡散用塗布液を作製し、実施例６と同様にして評価した。評価結果を表３に示す。 Example 7
In Example 2, an impurity diffusion coating solution was prepared in the same manner as in Example 2 except that 7 parts of triethyl borate (B4) was used as the impurity (B), and evaluated in the same manner as in Example 6. The evaluation results are shown in Table 3.
比較例１
　実施例１において、溶剤としてエチレングリコールとともに水を用い、各成分の配合量を表２に示すとおりとした以外は実施例１と同様にしてリン拡散用塗布液を作製し、同様に評価した。評価結果を表３に示す。 Comparative Example 1
In Example 1, a phosphorus diffusion coating solution was prepared and evaluated in the same manner as in Example 1 except that water was used together with ethylene glycol as the solvent, and the blending amounts of each component were as shown in Table 2. The evaluation results are shown in Table 3.
比較例２
　実施例１において、ＰＶＡ系樹脂（Ａ）に代えて平均重合度４５０のポリ酢酸ビニルを用い、不純物（Ｂ）としてリン酸エステル（Ｂ１）を用い、溶剤としてイソブチル酸－３－ヒドロキシ－２，２，４－トリメチルペンチルエステル（ＴＰＭ）を用い、界面活性剤（Ｄ）を配合せず、無機微粒子（Ｅ）としてコロイダルシリカ（フジミコーポレーション社製「ＰＬＡＮＥＲＬＩＴＥ　４１０１」）を配合し、各成分の配合量を表２に示すとおりとした。それ以外は実施例１と同様にしてリン拡散用塗布液を作製し、同様に評価した。評価結果を表３に示す。 Comparative Example 2
In Example 1, instead of PVA resin (A), polyvinyl acetate having an average polymerization degree of 450 was used, phosphoric acid ester (B1) was used as impurity (B), and isobutyric acid-3-hydroxy-2, 2,4-trimethylpentyl ester (TPM) is used, surfactant (D) is not blended, and colloidal silica (“PLALERITE 4101” manufactured by Fujimi Corporation) is blended as inorganic fine particles (E). The amount was as shown in Table 2. Other than that, the coating liquid for phosphorus diffusion was produced like Example 1, and evaluated similarly. The evaluation results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　本発明のリン拡散用塗布液はスクリーン印刷において、一定時間放置した後でも優れた印刷性が得られた。また、本発明の塗布液から得られた半導体は、上下の表面抵抗値の差が小さいものであった。
　一方、水を主体とする溶剤を用いた比較例１の塗布液は、３０分放置した後の印刷性が劣るものであり、バインダーとしてポリ酢酸ビニルを用いた比較例２の塗布液は、得られた半導体の上下の表面抵抗値の差が大きいものであった。 The phosphorus diffusion coating solution of the present invention obtained excellent printability even after being left for a certain time in screen printing. Moreover, the semiconductor obtained from the coating solution of the present invention had a small difference in the upper and lower surface resistance values.
On the other hand, the coating solution of Comparative Example 1 using a solvent mainly composed of water is inferior in printability after being left for 30 minutes, and the coating solution of Comparative Example 2 using polyvinyl acetate as a binder is obtained. The difference in the surface resistance value between the upper and lower surfaces of the obtained semiconductor was large.
　なお、上記実施例においては、本発明における具体的な形態について示したが、上記実施例は単なる例示にすぎず、限定的に解釈されるものではない。当業者に明らかな様々な変形は、本発明の範囲内であることが企図されている。 In addition, although the specific form in this invention was shown in the said Example, the said Example is only a mere illustration and is not interpreted limitedly. Various modifications apparent to those skilled in the art are contemplated to be within the scope of this invention.
　本発明の不純物拡散用塗布液は、長時間の連続印刷や休止期間をおいた印刷が可能であり、皮膜形成後の半導体基板を直立状態で焼成したとしても抵抗値の上下バラツキが小さい半導体が得られることから、工業的に極めて有用である。 The coating solution for impurity diffusion of the present invention can be printed continuously for a long time or with a rest period, and even if the semiconductor substrate after film formation is baked in an upright state, a semiconductor with small variation in resistance value can be obtained. Since it is obtained, it is extremely useful industrially.

Claims (6)

  1. 　ポリビニルアルコール系樹脂（Ａ）、不純物（Ｂ）、および沸点が１００℃以上の多価アルコール（Ｃ）を含有し、該多価アルコール（Ｃ）の含有量が塗布液中の７０重量％以上であることを特徴とする不純物拡散用塗布液。 A polyvinyl alcohol resin (A), an impurity (B), and a polyhydric alcohol (C) having a boiling point of 100 ° C. or higher are contained, and the content of the polyhydric alcohol (C) is 70% by weight or more in the coating solution. A coating liquid for impurity diffusion, characterized by
  2. 　ポリビニルアルコール系樹脂（Ａ）が、ケン化度が５０～９０モル％のポリビニルアルコール系樹脂（Ａ）である請求項１記載の不純物拡散用塗布液。 The coating solution for impurity diffusion according to claim 1, wherein the polyvinyl alcohol resin (A) is a polyvinyl alcohol resin (A) having a saponification degree of 50 to 90 mol%.
  3. 　ポリビニルアルコール系樹脂（Ａ）が、下記一般式（１）で表わされる構造単位を５～１０モル％含有するポリビニルアルコール系樹脂である請求項１または２記載の不純物拡散用塗布液。
    Figure JPOXMLDOC01-appb-C000001
         3. The impurity diffusion coating solution according to claim 1, wherein the polyvinyl alcohol resin (A) is a polyvinyl alcohol resin containing 5 to 10 mol% of a structural unit represented by the following general formula (1).
    Figure JPOXMLDOC01-appb-C000001
  4. 　不純物（Ｂ）が、１３族元素化合物および１５族元素化合物の少なくとも一つである請求項１～３いずれか記載の不純物拡散用塗布液。 4. The impurity diffusion coating solution according to claim 1, wherein the impurity (B) is at least one of a group 13 element compound and a group 15 element compound.
  5. 　界面活性剤（Ｄ）を含有する請求項１～４いずれか記載の不純物拡散用塗布液。 The coating solution for impurity diffusion according to any one of claims 1 to 4, comprising a surfactant (D).
  6. 　無機微粒子（Ｅ）を含有する請求項１～５いずれか記載の不純物拡散用塗布液。 The coating solution for impurity diffusion according to any one of claims 1 to 5, comprising inorganic fine particles (E).
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