JPH0366661B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing circuit boards using a thin film cast from a solution of a special curable composition as a photoresist. Such specialized curable compositions include, by weight, (A) 0.5% to 98% epoxy resin, (B) 0.5% to 98% polyvinyl acetal, and (C) 0.1% to 10% aromatic onium salt. The sum of (A), (B) and (C) above is 100%,
(C) is an aromatic halonium salt represented by formula (1) [(R)a(R ¹ )bD] _c ⁺ [MQd] ^-de , and formula (2) [(R)f(R ² )g( R ³ ) hE〕 _c ⁺ [MQd] ^- aromatic onium salt of group a element represented by _de ;
or formula (3) [(R)j(R ⁴ )k(R ⁵ )mG] _c ⁺ [MQd] - aromatic onium salt of a group a element represented by ^-de (where R is a monovalent aromatic group organic group, R ¹ is a divalent aromatic organic group, R ² and R ⁴ are monovalent aliphatic organic groups selected from alkyl, cycloalkyl and substituted alkyl, R ³ and R ⁵ are E or G and A polyvalent organic group forming a heterocyclic or condensed ring structure, D is a halogen group, e.g. I, E is a group a element selected from N, P, As, Sb and Bi, and G is selected from S, Se and Te. M is a metal or metalloid, Q is a halogen group, a is an integer of 1 or 2, b is an integer of 0 or 1, the sum of a + b is 2 or the valence of D, f is 0 to 4
g is an integer of 0 to 2, h is an integer of 0 to 2,
The sum of f + g + h is 4 or the valence of E, j is 0 to 3
k is an integer of 0 to 2, m is an integer of 0 or 1, the sum of j+k+m is 3 or the valence of G, c=d
-e, e is the valence of M and is an integer from 2 to 7, and d is an integer greater than e and up to 8). The groups encompassed by R may be the same or different and are aromatic carbocyclic or heterocyclic groups of 6 to 20 carbon atoms, such as C _1-8 alkoxy, C _1-8 alkyl, nitro, It may be substituted with 1 to 4 monovalent groups selected from chloro and the like. R is more specifically phenyl,
These include chlorophenyl, nitrophenyl, methoxyphenyl, pyridyl, and the like. The groups included in R ¹ are divalent groups, such as

【formula】

[Formula]. R ² and R ⁴ groups include C _1-8 alkyl such as methyl, ethyl, etc., substituted alkyl such as -C ₂ H ₄ OCH ₃ , -
_CH2COOC2H5 , _{-CH2COCH3 , etc.} are included _. ^R3
and for R ⁵ groups

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

Structures such as [Formula] are included, Q' is selected from O, CH ₂ , N, R and S, and Z
are O, S and

and R' is a monovalent group selected from hydrogen and carbon-hydrogen. The metals or metalloids encompassed by M in formula 1 are transition metals such as Sb, Fe, Sn, Bi, Al, Ga, In,
Ti, Zr, Sc, V, Cr, Mn, Cs, rare earth elements such as lanthanides such as Cd, Pr, Nd, etc., actinides such as Th, Pa, U, Np, etc., and metalloids such as B, P, As, etc. Complex anions encompassed by MQd ^-(de) are, for example, BF ₄ ^- , PF ₆ ^- , AsF ₆ ^- ,
These include SbF ₆ ^- , FeCl ₄ ^- , SnCl ₆ ^- , SbCl ₆ ^- , BiCl ₅ ^- , etc. Halonium salts encompassed by formula 1 are e.g.

【formula】 【formula】

【formula】

【formula】

[Formula]. Group a onium salts encompassed by formula 2 are e.g. It is. Group a onium salts encompassed by formula 3 include, for example: etc. Onium salts of formulas 1-3 can be prepared in a variety of ways. The onium salt of formula 1 can be prepared by combining the arylhalonium hydrogensulfate salt under aqueous conditions with the corresponding hexafluoric acid or salt such as Y ¹ MF ₆ (where Y ¹ is hydrogen, an alkali metal ion, an alkaline earth metal ion or transition metal ions). In addition to the above metathesis to produce the corresponding halonium salts, MCCaserio uses silver compounds such as silver oxide or silver tetrafluoroborate salts and reacts them with suitable diarylhalonium salts. journals such as
of the American Chemical Society (J.
Am.Chem.Soc.) 81336 (1959) or Journal of American Chemical Society (J.Am.Chem.soc.) 81342 (1959) of M.C. Beringer et al. It can also be prepared by the method shown in . Group A compounds, such as sulfonium, selenonium and telluronium compounds, can be found in the Journal of American Chemical Society (J.Am.Chem.Soc.) of JWKnapczyk and WEMcEwen. 91 145, (1969), AL Maycock and GABerchtold, Journal of Organic Chemistry (J.Org.Chem), 35 No. 8, 2532 (1970), H.・US Patent No. of HMPitt
No. 2807648, E. Goisars and P.
De Radozecki (E.Goethals and P.De
Radzetzky's Bulletin of Society of Chemistry of Belgium (Bul.
Soc.Chem.Belg), 73 546 (1964), HMLeichester and F.W.
Bergstrom) Journal of American
Chemical Society (J.Am.Chem.Soc.)
51 3587 (1929) etc. A process that can be used to produce Group A onium salts such as arsonium, antimonium and bismasonium is described by Goerdeler.
Methoden der Organishen Chimie 11/2,
591-640 (1958) and K. Sasse, Idid, 12/1 79-112 (1963). The term "epoxy resin" as used in describing the above curable compositions includes any monomeric, dimeric, oligomeric or polymeric epoxy material containing one or more epoxy functional groups.
For example, those resulting from the reaction of bisphenol-A (4,4'-isopropylidene diphenol) with epichlorohydrin or the reaction of low molecular weight phenol-formaldehyde resins (novolac resins) with epichlorohydrin. These resins can be used alone or in combination with epoxy-containing compounds as reactive diluents. Diluents such as phenyl glycidyl ether, 4-vinylcyclohexene dioxide, limonene dioxide, 1,2-cyclohexene oxide, glycidyl acrylate, glycidyl methacrylate, styrene oxide, and allyl glycidyl ether can be added as viscosity modifiers. Additionally, the scope of these compounds can be extended to include polymeric materials containing terminating or pendant epoxy groups. Examples of these compounds are vinyl copolymers containing glycidyl acrylate or methacrylate as one of the comonomers. Other classes of epoxy-containing polymers that are subject to curing using the above catalysts are epoxy-siloxane resins, epoxy-polyurethanes and epoxy-polyesters. These polymers typically have epoxy functionality at the end of the polymer chain. Epoxy-siloxane resins and their manufacturing methods are described by E.P. Plueddemann and G.
Franger) Journal of American Chemical Society (J.Am.Chem.Soc.) 80
632-5 (1959). As described in the literature, epoxy resins can also contain e.g. amines, carboxylic acids, thiols, phenols,
Denaturation can be accomplished by a number of standard methods, such as reaction with alcohols, etc., as described for example in U.S. Pat.
No. 2935488, No. 3235620, No. 3369055, No.
No. 3379653, No. 3398211, No. 3403199, No.
No. 3563850, No. 3567797, No. 3677995, etc. Further examples of epoxy resins that can be used can be found in the Encyclopedia of Polymer Science and Technology.
Polymer Science and Technology), Volume 6,
1967, Interscience Publishers,
New York (Intersciene PublisherS.New
York), p. 209271. In addition, polyvinyl acetals that can be used in the above curable composition include, for example, as well as but and wherein the polymer can contain on average about 5 to 5000 units, R ⁶ is hydrogen, C _1-8 alkyl, e.g. methyl,
Selected from ethyl, butyl and mixtures thereof. Polyvinyl acetals that can be used in the practice of this invention are further described in the Encyclopedia of Polymer Science and Technology.
Technology), HFMark and NG Gaylord
Gaylord, Vol. 14, p. 149 (1971). The curable composition described above can be cast from an organic solvent solution into a dry thin film photoresist.
Suitable organic solvents that can be used include, for example, methylene chloride, chloroform, methyl ethyl ketone, cellosolve acetate, tetrahydrofuran, acetonitrile, etc., used in an amount of 0 to 80% by weight of the curable composition. This curable composition can be cured at temperatures of 100-200°C. Preferably, the above-described curable composition can be exposed to ultraviolet light to form a cast thin film in a solvent-resistant state. When used as a dry thin film photoresist, the wavelength is 1849 Å to 4000 Å and the intensity is at least 5000~
By irradiating ultraviolet light at 80,000μW/cm ² , patterns can be created on a thin film using a mask. The lamp systems used for the generation of such radiation include ultraviolet lamps, e.g. formed by individuals. The lamp has a wavelength of approximately 1849
It may include a jacket capable of transmitting light between 2400 Å and 4000 Å, preferably between 2400 Å and 4000 Å. The lamp envelope can be made of quartz, such as Spectrocil or Pyrex. Typical lamps that can be used to provide ultraviolet radiation include medium pressure mercury arc lamps, e.g.
GEHT37 arc lamp and Hanovia 450W arc lamp. Curing can be effected by various lamp combinations, all or part of which can be operated in an inert atmosphere. For curing of dry thin film photoresists using ultraviolet lamps, the radiation flux impinging on the substrate may be at least 0.01 watts per square inch. 100 per 100 parts of epoxy resin for curable compositions
% of inert ingredients such as inorganic fillers, dyes, pigments, bulking agents, viscosity control agents, processing aids, ultraviolet light shielding agents, and the like. The curable composition is a metal,
Rubber, plastics, molded parts, thin films, paper, wood,
It can be applied to substrates such as glass, cloth, concrete, ceramics, etc. Examples and reference examples are shown below to facilitate understanding of the present invention, but these are merely illustrative and do not have a limiting meaning. All parts are parts by weight. Reference example 1 Polyvinyl formal (Monsanto
Formvar12/85) 10 copies, Ciba-Geigy Araldite
A solution consisting of 25 parts of ECN 1299 cresol-novolac epoxy resin, 0.3 parts of triphenylsulfonium hexafluoroantimonate, and about 80 parts of chloroform was cast onto a glass plate to form a 5 mil thin film. The film was stripped and exposed through a glass contact mask to ultraviolet light from a GEHT37 medium pressure mercury arc lamp at a distance of 6 inches for 3 minutes. After irradiation, a visible image was observed in the thin film. The film was immersed in chloroform to develop the latent image. A negative image of the mask was formed in the thin film. Reference example 2 Formvar15/95 E polyvinyl formal 10
Part, epoxy resin of Reference Example 1 (ECN 1299) 5
A solution prepared from 0.3 parts triphenylsulfonium hexafluoroantimonate and 80 parts methylene chloride was cast as a 5 mil thin film onto a polyethylene terephthalate substrate. A contact mask was then placed on top of the resulting composite and exposed under ultraviolet light for 3 minutes as described in Reference Example 1. The composite thus obtained was then developed by immersing it in 2-ethoxyethyl acetate. A polyethylene terephthalate substrate was thus obtained with a negative image of the mask on its surface, which was useful as a printing plate. Reference example 3 Formvar 15/95 E10 parts, triphenylsulfonium hexafluoroarsenate 0.3 parts,
5 parts of Araldite ECN 1299 and approx. methylene chloride
A curable composition was prepared by dissolving 80 parts. The resulting solution was then cast onto a glass plate. When the solvent was evaporated from this solution, a translucent thin film was obtained. This thin film was then peeled off from the glass substrate and brought into contact with a mask. The film was then irradiated as described in Reference Example 1 for about 1.5 minutes. The film was then heated in an oven to 100°C for 5 minutes. Developing the thin film using chloroform reproduced the sharp negative of the mask. Example 10 parts of reaction product of polyvinyl alcohol and butyraldehyde (ButvarB-74), Araldite ECN
2.5 parts of 1299, 0.3 parts of triphenylsulfonium hexafluoroarsenate and approx.
A thin film was cast onto a glass plate from a curable composition consisting of 90 parts. The film was peeled from the glass plate and then laminated onto a copper-coated epoxy-glass circuit board at 130°C under pressure. The laminate was exposed to ultraviolet light using a contact mask as in Reference Example 1. The laminate was then developed using chloroform to produce a negative image of the curable resin on the copper.
The copper laminate was then etched using ferric chloride. A copper coated laminate was obtained with a positive image of the mask in the copper on the surface of the epoxy glass substrate. Reference Example 4 In a composition using triphenylsulfonium hexafluoroantimonate as a photoinitiator,
Curable compositions were prepared as described in the Examples except that 0.1 part of Dayglo T-13 pigment was used.
A thin film was cast onto a piece of polyethylene terephthalate sheet. After drying the film, it was covered with a contact mask and exposed to ultraviolet light as described in Reference Example 1. The thus irradiated photosensitive thin film-polyethylene terephthalate composite was then brought into contact with a flat white paper and heated to 130 DEG C. under pressure. A clear negative image of the mask was obtained on white paper. It was found that this composite could be used to transfer clear negative images of the mask onto several additional sheets of paper following the same procedure. The following reference examples illustrate the use of diarylhalonium salts with certain organic dyes as visible light photoinitiators for epoxy resins. Reference example 5 Formwar15/95 E10 part, Araldite ECN 1299
2.5 parts of diphenyl iodonium hexafluoroarsenate, 0.1 part of benzoflavin, and about 80 parts of methylene chloride.
Cast onto Mylar thin film. After drying the film, it was subjected to imagewise exposure using a visible light source, a GE375W photographic bulb. A clear image was formed in the thin film after 5 minutes of irradiation. The latent image was developed using chloroform, 2-ethoxyethyl acetate or methylene chloride, resulting in a sharply raised replica of the mask. As can be seen from the examples, the curable composition described above can be used as a dry thin film photoresist to produce copper-clad circuit boards. The above steps were repeated, except using acridine orange instead of benzoflavin. Additionally, a third film was cast using phosphene-R dye instead of benzoflavin. Substantially equivalent results were obtained with each of the above dyes used in place of benzoflavin. A curable composition was prepared as described above by replacing Formvar 15/95 E with an equal amount of ethylcellulose. Thin films were cast from this mixture and subjected to imagewise exposure using a contact mask. When an attempt was made to develop this thin film, the exposed thin film was completely dissolved in chloroform. This indicates that crosslinking did not occur in the absence of the polyvinyl acetal required to make the dry thin film photoresist. In addition to the dyes mentioned above for use in visible light curable compositions as described above, other dyes that can be used with the diphenylmodrium salt include, for example, Kirkoo osmer.
Encyclopedia, 2nd edition (Kirk-
Othmer Encyclopedia, second edition) 1965,
Volume 20, pp. 194-7, John Willy &
Sons, New York (John Wiley & Sons,
(New York). In addition to the cationic dyes mentioned above, basic dyes can also be used and are described in the Kirk-Osmer Encyclopedia mentioned above.
Othmer Encyclopedia), Volume 7, pages 532-4. Some examples of cationic dyes that can be used are Acridine Orange CI46005 Acridine Yellow CI46025 Cetoflavin T CI49005. Furthermore, some examples of basic dyes that can be used include hematoporphyrin, 4,4'-bisdimethylaminobenzophenone, and 4,4'-bisdiethylaminobenzophenone.

Claims (1)

[Scope of Claims] 1 (a) (A) 0.5% to 98% epoxy resin, (B) 0.5% to 98% polyvinyl acetal, and (C) 0.1% to 10% aromatic onium salt, by weight. , where the sum of (A), (B) and (C) above is 100%, and (C) above is the formula [(R)a(R ¹ )bD] _C ⁺ [MQd] ^- Aromatic halonium salt represented by ^de , formula [R) f(R ² ) g (R ³ ) hE] _c ⁺ [MQd] ^- aromatic onium salt of group a element represented by de and formula [(R) j (R ⁴ ) k (R ⁵ ) mG] _c ⁺ [MQd] ^- aromatic onium salt of group a element represented by -de (where R is a monovalent aromatic organic group, R' is a divalent aromatic organic group) aromatic organic group; R ² and R ⁴ are monovalent aliphatic organic groups selected from alkyl, cycloalkyl, and substituted alkyl; R ³ and R ⁵ are aliphatic groups that form a heterocycle or fused ring with E or G; polyvalent organic group selected from groups and aromatic groups, D is halogen, e.g. I, E is N,
a group a element selected from P, As, Sb and Bi;
G is a group a element selected from S, Se and Te;
M is a metal or metalloid, Q is a halogen, a is an integer of 0 or 2, b is an integer of 0 or 1, sum a + b is a valence of 2 or D, f is an integer of 0 to 4, g is 0 to 2 h is an integer of 0 to 2, the sum f + g + h is 4 or the valence of E, j is an integer of 0 to 3, k is an integer of 0 to 2, m is an integer of 0 or 1, sum j + k + m is 3 or The valence of G, c=de, e is the valence of M, 2~
7, and d is an integer greater than e and up to 8), and mixtures thereof. b placing a contact mask on the cast thin film of the composite structure of a. c. exposing the composite structure to ultraviolet light to cure exposed areas of the cast thin film of the composite structure of a. d After removing the contact mask, the resulting exposed composite structure is immersed in a solvent to remove the uncured areas of the cast film and develop the latent image in the cast film, thereby contacting. producing a copper clad laminate protected by a cured cast film patterned as a negative image of the mask and acting as a photoresist; e. etching said copper clad laminate to remove exposed areas of copper; and removing the cured cast thin film photoresist from the resulting copper-coated laminate to produce a copper-coated circuit board patterned as a positive image of a contact mask. Manufacturing method.