Light-Sensitive Composition Containing Onium Salt and Polysiloxane Reaction Product

The present invention relates to a positive working light-sensitive composition which makes it possible to form a presensitized plate for use in making a lithographic printing plate (hereunder referred to as "PS plate"), proof sheets for process printing, figures for overhead projectors or fine resist patterns required for making integrated circuits (IC) of semiconductor elements.

A light-sensitive composition comprising an o-naphthoquinonediazide compound and a novolak type phenol resin has widely been used as an excellent light-sensitive composition for making a lithographic printing plate.

However, the light-sensitive composition is poor in adhesion to a substrate for a printing plate, coating property and abrasion resistance and low in a film strength owing to the property of the novolak type phenol resin which is a main component and therefore it provides only a lithographic printing plate having insufficient printing durability.

On the other hand, as pattern-forming methods used in making electronic parts such as semiconductor elements, magnetic bubble memories and integrated circuits, there have been widely employed methods in which a photoresist sensitive to ultraviolet and visible rays. The photoresists are classified into two groups, one of which is negative working type ones whose exposed portions are made insoluble in a developer by irradiating with light, and the other of which is positive working ones whose exposed portions are, on the contrary, made soluble in a developer. The negative working type ones are superior in sensitivity to the positive working ones and adhesion to a substrate and resistance to chemicals required in wet etching are also excellent. Therefore, the use of negative working resists is one of the mainstreams of photolithography. However, the line width and the distance between lines of patterns become smaller as the degree of integration of semiconductor elements and the packaging density thereof are increased. In addition, dry etching techniques have been adopted as a means for etching substrates. Thus, the photoresists should have high resolution and high resistance to dry etching. For these reasons, positive working photoresists are mainly utilized recently. In particular, there have been exclusively used alkali developable positive working photoresists mainly composed of alkali-soluble novolak resins as disclosed in J.C. Strieter, Kodak Microelectronics Seminar Proceedings, 1976, p. 116, since they are excellent in sensitivity, resolution and resistance to dry etching. There have been proposed many other positive working photoresists such as a light-sensitive compositions comprising a combination of a phenolic resin and an onium salt as disclosed in Journal of Electrochemical Society, Vol. 135, p2322, 1988.

However, it is required to further scale down the size of patterns to thus achieve much higher packaging density and degree of integration accompanied by the recent increase in multifunctionality and high functionality of electronic devices.

More specifically, the size of integrated circuits in their transversal direction is greatly reduced, but the size thereof in the longitudinal direction cannot be reduced so much. Therefore, the ratio of the height of the resist patterns to the width thereof is correspondingly increased. For this reason, it becomes very difficult to restrict the change in size of the resist patterns on a semiconductor wafer having a complicated stepped structure as the scale down of patterns proceeds. In addition, various methods for exposure suffer from problems as the scale down in the minimum size of patterns proceeds. For instance, the exposure by means of light causes interference effect due to light reflected by the stepped portions of the substrate which greatly affects dimensional accuracy. On the other hand, in the exposure by means of an electron beam, the ratio of the height to the width of fine resist patterns cannot be increased because of the proximity effect caused due to backscattering of electrons.

It is found that most of these problems can be eliminated by the use of a multilayered resist system. The multilayered resist system is summarized in Solid State Technology, 74 (1981) and a variety of investigations on the multilayered resist system have been reported. In general, the multilayered resist methods are classified into triple layer resist method and double layer resist method. The triple layer resist method comprises applying an organic film for leveling onto the surface of a stepped substrate, and then applying thereto an inorganic intermediate layer and a resist layer in this order; patterning the resist layer, dry etching the inorganic layer using the patterned resist layer as a mask, and finally patterning the organic leveling layer by O.sub.2 RIE (reactive ion etching) technique using the inorganic layer as a mask to form a desired pattern on the stepped substrate. The investigation of this method has been started from earlier stage since it can essentially utilize techniques conventionally known, but it requires the use of very complicated processes, or since these layers, i.e., an organic film, an inorganic film and an organic film which differ in physical properties from each other are superposed, the intermediate layer is liable to cause cracks or to form pinholes. Contrary to the triple layer resist method, the double layer resist method utilizes a resist having properties of both resist and inorganic intermediate layers in the triple layer resist method, more specifically a resist resistant to oxygen plasma etching and thus the formation of cracks and pinholes can be suppressed. Further, since the number of layers are reduced from 3 to 2, the process can be simplified. However, a conventional resist can be used as the upper resist in the triple layer resist method while, in the double layer resist method, it is required to newly develop a resist excellent in resistance to oxygen plasma.

Under such circumstances, there has been required to develop a highly sensitive positive working photoresist having a high degree of resolution which is excellent in resistance to oxygen plasma and can hence be used as an upper resist in the double layer resist method or the like, in particular an alkaline developable resist which can be used without changing the processes currently employed.

As such a resist, there have been proposed light-sensitive compositions comprising a combination of a conventional o-quinonediazide light-sensitive material and a silicone polymer such as polysiloxane or polysilmethylene which is made alkali-soluble, for instance, those disclosed in J.P. KOKAI Nos. Sho 61-144639, Sho 61-256347, Sho 62-159141, Sho 62-191849, Sho 62-220949, Sho 62-229136, Sho 63-90534 and Sho 63-91654 and U.S. Pat. No. 4,722,881.

All these silicone polymers are made alkali soluble by introduction of phenolic OH group or silanol group (.tbd.Si--OH). The introduction of phenolic groups are very difficult and silicone polymers having silanol groups are not always stable over time.

On the other hand, the positive working photoresist comprising an alkali soluble resin and an onium salt is poor in O.sub.2 RIE property if a phenolic resin is used as an alkali soluble resin, while the positive working photoresist is very difficult to be produced if a polysiloxane/carbonate block copolymer disclosed ih J.P.KOKAI No. Sho 62-136638 is used.

Accordingly, an object of the present invention is to provide a novel positive working light-sensitive composition which makes it possible to solve the foregoing problems, more specifically to provide a novel positive working light-sensitive composition which is useful for making a lithographic printing plate and which has high adhesion to a substrate and good coating property.

Another object of the present invention is to provide an alkali-developable positive working light-sensitive composition exhibiting excellent resistance to oxygen plasma.

A further object of the present invention is to provide a novel positive working light-sensitive composition which can easily be produced and can hence be easily available.

The inventors of this invention have conducted various studies to achieve the foregoing objects and have completed the present invention.

The present invention provides a light-sensitive composition comprising:

(a) a polysiloxane compound having at least 1 mol% of structural unit derived from a product of a thermal cycloaddition reaction between a compound of formula (I), (II), (III) or (IV) (hereinafter referred to as (A)) and a compound of formula (V), (VI), (VII) or (VIII) (hereinafter referred to as (B)) described below, and

b) an onium salt compound of formula (IX) or (X).

The present invention will now be explained in detail. ##STR2##

In the above formulas, R.sup.1 to R.sup.5 may be same or different and represent hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, silyl, substituted silyl, siloxy or substituted siloxy groups. More specifically, the alkyl group is linear, branched or cyclic and preferably has about 1 to about 10 carbon atoms such as methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, isopropyl, isobutyl, tert-butyl, 2-ethylhexyl or cyclohexyl. The substituted alkyl group is the above mentioned alkyl group substituted by a halogen atom such as chlorine, an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aryl group such as a phenyl group, an aryloxy group such as a phenoxy group, a nitro or a cyano group, specifically monochloromethyl, dichloromethyl, trichloromethyl, bromomethyl, 2-chloroethyl, 2-bromoethyl, 2-methoxyethyl, 2-ethoxyethyl, phenylmethyl, naphtylmethyl, phenoxymethyl, 2-nitroethyl or 2-cyanoethyl. The aryl group is mono- or dicyclic, more specifically phenyl, .alpha.-naphtyl or .beta.-naphtyl group. The substituted aryl group is the above mentioned aryl group substituted by an alkyl group having 1 to 6 carbon atoms such as methyl or ethyl, an alkoxy group having 1 to 6 carbon atoms such as methoxy or ethoxy, a halogen atom such as chlorine, a nitro, phenyl, carboxy, hydroxy, amide, imide or cyano group, and more specifically 4-chlorophenyl, 2-chlorophenyl, 4-bromophenyl, 4-nitrophenyl, 4-hydroxyphenyl, 4-phenylphenyl,4-methylphenyl, 2-methylphenyl, 4-ethylphenyl, 4-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 2-carboxyphenyl, 4-cyanophenyl, 4-methyl-1-naphtyl, 4-chloro-1-naphtyl, 5-nitro-1-naphtyl, 5-hydroxy-1-naphtyl, 6-chloro-2-naphtyl, 4-bromo-2-naphtyl or 5-hydroxy-2-naphtyl group. The substituted silyl group is, for instance, an alkyl silyl group such as a trialkyl silyl group or an aryl silyl group such as a triaryl silyl group, the alkyl or the aryl group being same as mentioned above.

If these substituents each represents a siloxy or substituted siloxy group, these groups may be those bonded with siloxy or substituted siloxy groups of the adjacent structural units or those having a two-dimensional or three-dimensional structure such as those formed by bonding the siloxy or substituted siloxy group to that of other molecule as will be describe below: ##STR3##

R.sup.6 represents hydrogen, an alkyl, substituted alkyl, aryl, substituted aryl, ##STR4## Specific examples of the alkyl, the substituted alkyl, the aryl and the substituted aryl groups are the same as those of R.sup.1 to R.sup.5.

R.sup.7 to R.sup.9 represent hydrogen, an alkyl, substituted alkyl, aryl, substituted aryl, alkoxy, substituted alkoxy, cyano, nitro, --P.sup.1 --Q or ##STR5## which may contain --0--, --CO--, --COO--, --OCO--, --CONR.sup.13 --, --NR.sup.13 CO--, --SO.sub.2 --or --SO.sub.3 --. Preferred examples of the alkyl and the substituted alkyl groups are those having 1 to 10 carbon atoms and preferred examples of the aryl and the substituted aryl groups are those having 6 to 14 carbon atoms, more specifically are the same as those of R.sup.1 to R.sup.5.

R.sup.13 represents hydrogen, an alkyl, substituted alkyl, aryl or substituted aryl group, preferably hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms or a substituted aryl group having 6 to 14 carbon atoms. Specific examples of the alkyl, the substituted alkyl, the aryl and the substituted aryl groups are the same as those of R.sup.1 to R.sup.5.

R.sup.7 and R.sup.8 or R.sup.7 and P.sup.1 may combine to form a ring.

X.sup.1 to X.sup.3 represent hydroxy groups or hydrolyzable groups, preferably halogen atoms such as chlorine or bromine, alkoxy groups having 1 to 10 carbon atoms such as methoxy, ethoxy or propoxy groups, aryloxy groups having 6 to 10 carbon atoms such as aryloxy groups, acyloxy groups having 1 to 10 carbon atoms such as acetoxy groups, oxime groups having 1 to 6 carbon atoms such as methylaldoxime, amide, ureide or amino groups.

P.sup.1 to P.sup.3 represent single bonds, alkylene, substituted alkylene, arylene or substituted arylene groups which may contain --O--, --CO--, --COO--, --OCO--, --CONR.sup.13, --NR.sup.13 CO--, --SO.sub.2 --or --SO.sub.2 --.

Specific examples of the alkylene groups include linear, branched or cyclic ones preferably linear ones having 1 to 10 carbon atoms such as methylene, ethylene, butylene or octylene groups The substituted alkylene groups are the above mentioned alkylene groups substituted by, for example, a halogen atom such as chlorine, an alkoxy group having 1 to 6 carbon atoms or an ayloxy group having 6 to 10 carbon atoms. The arylene groups are preferably mono- or di-cyclic ones such as phenylene or naphtylene groups. The substituted arylene groups are the above mentioned arylene groups substituted by an alkyl group having 1 to 6 carbon atoms such as methyl or ethyl group, an alkoxy group having 1 to 6 carbon atoms such as methoxy or ethoxy group or a halogen atom such as chlorine. Specific examples include chlorophenylene, bromophenylene, nitrophenylene, phenylphenylene, methylphenylene, ethylphenylene, methoxyphenylene, ethoxyphenylene, cyanophenylene, methylnaphtylene, chloronaphtylene, bromonaphtylene or nitronaphtylene group.

Y represents a trivalent aromatic ring preferably having 6 to 14 carbon atoms.

Q represents an acid group having pKa of not more than 12, specifically a carboxyl, sulfonic, phenolic hydroxyl, imide, N-hydroxyimide, N-sulfonylamide, sulfonamide, N-sulfonylurethane, N-sulfonylureide or a group having an active methylene group, more specifically ##STR6## wherein m is an integer of 1 to 5.

Z.sub.1 represents ##STR7## wherein Y.sup.a+2 represents an (n+2) valent aromatic ring, preferably having 6 to 14 carbon atoms and n is an integer of 1 to 3. Specific examples of Z.sub.1 follow. ##STR8##

Ar.sup.1 and Ar.sup.2 may be same or different and each represents a substituted or unsubstituted aryl group. Examples of preferred substituents of the aryl groups are alkyl, haloalkyl, cycloalkyl, alkoxy, nitro, carbonyl, alkoxycarbonyl, hydroxy and mercapto groups and halogen atoms, more preferably alkyl groups having 1 to 8 carbon atoms, alkoxy groups having 1 to 8 carbon atoms, nitro group and chlorine atom. R.sup.10, R.sup.11 and R.sup.12 may be same or different and each represents a substituted or unsubstituted alkyl or aryl group, preferably an aryl group having 6 to 14 carbon atoms, an alkyl group having 1 to 8 carbon atoms or a substituted derivative thereof. Examples of preferred substituents for the aryl groups are alkoxy groups having 1 to 8 carbon atoms, alkyl groups having 1 to 8 carbon atoms, nitro, carbonyl and hydroxyl groups and halogen atoms and those for alkyl groups are alkoxy groups having 1 to 8 carbon atoms, carbonyl group and alkoxycarbonyl groups. Z,- represents BF.sub.4 --, PF.sub.6 -- AsF.sub.4 -- SbF.sub.6 -- ClO.sub.4 -- , CF.sub.3 SO.sub.3 -- and R.sup.10 SO.sub.3,--Moreover, two of the groups R.sup.10, R.sup.11 and R.sup.12, or Ar.sup.1 and Ar.sup.2 each may be bonded through a single bond or a substituent.

The components of the light-sensitive composition of the present invention will now be explained in detail.

The polysiloxane compound of the present invention is a polysiloxane containing at least 1 mol%, preferably at least 3 mol%, more preferably at least 5 mol% of a siloxane unit derived from a thermal cycloaddition reaction, i.e. Diels-Alder reaction product represented by formulas (XI) to (XXVI) between polysiloxane compounds (A) and (B). ##STR9## wherein R.sup.1 to R.sup.9, P.sup.1 to P.sup.3, Q, X.sup.1 to X.sup.3, Y.sup.3 and A.sub.z are same as defined above.

The polysiloxane compounds of the present invention may be prepared by a process which comprises the steps of:

(i) hydrolyzing or alkoxylating at least one compound (A);

(ii) subjecting the hydrolyzed or alkoxylated product of step

(i) to a condensation reaction; and

(iii) subjecting the condensate of step (ii) to a thermal cycloaddition reaction with at least one compound (B), whereby a polysiloxane compound is produced; or

a process which comprises the steps of:

(i) subjecting at least one compound (A) and at least one compound (B) to a thermal cycloaddition reaction to prepare a compound of formula (XI) to (XXVI);

(ii) hydrolyzing or alkoxylating the reaction product of step

(i); and

(iii) subjecting the hydrolyzed or alkoxylated product of step

(ii) to a condensation reaction, whereby a polysiloxane compound is produced.

Both the processes are simple and do not require a metal catalyst.

At least one compound of formula (XXVII) to (XXXI) may coexist with the compound of formula (XI) to (XXVI) in the reaction system to improve properties of the polysiloxane compound of the present invention. In this case, the polysiloxane obtained by the co-condensation must contain at least 1 mol%, preferably, in view of alkali-solubility of the polysiloxane, at least 3 mol%, more preferably at least 5 mol% of the siloxane unit derived from the thermal cycloaddition reaction product between compounds (A) and (B). ##STR10##

In the formulas, R.sup.14 to R.sup.17 represent hydrogen, alkyl, substituted alkyl, aryl or substituted aryl groups, specific examples of which are the same as described for R.sup.4.

X.sup.4 to X.sup.7 represent hydroxyl or hydrolyzable groups, specific examples of which are the same as described for X.sup.1 to X.sup.3.

P.sup.4 represents a single bond, an alkylene, substituted alkylene, arylene or substituted arylene group. These groups may contain --O--, --CO--, --COO--, --OCO--, --CONR.sup.13 --, --NR.sup.13 CO--, --SO.sub.2 --or --SO.sub.3 --, specific examples of which are the same as described for P.sup.1 to P.sup.3.

It is also possible to coexist at least one compound of formula (XXXII) or (XXXIII) during the thermal addition reaction of compounds (A) and (B) to improve the properties of the polysiloxane compounds of the present invention. ##STR11##

D.sup.1 and D.sup.2 may be same or different and may combine to form a ring. Both of them do not contain an acid group having pKa of not more than 12, and preferably represent hydrogen, alkyl, substituted alkyl, aryl, substituted aryl, alkoxy, substituted alkoxy, silyl, substituted silyl, siloxy, substituted siloxy, cyano or nitro groups, more preferably hydrogen, alkyl groups having 1 to 10 carbon atoms, substituted alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 14 carbon atoms or substituted aryl groups having 6 to 14 carbon atoms. These groups may contain --O--, --CO--, --COO--, --OCO--, --CONR.sup.13 --, --NR.sup.13 CO--, --SO.sub.2 --or --SO.sub.3 --. In this case, the polysiloxane compound obtained must contain at least 1 mol%, preferably at least 3 mol%, more preferably at least 5 mol% of the siloxane unit derived from the thermal cycloaddition reaction product between compounds (A) and (B).

The thermal cycloaddition reaction is carried out at a temperature ranging preferably from 50.degree. C. to 200.degree. C., more preferably from 70.degree. C. to 140.degree. C.

The weight average molecular weight of the polysiloxane the present invention is preferably at least 500, more preferably 1,000 to 500,000.

In the synthesis of the polysiloxane compound of the present invention, a solvent may be used. Examples of the solvent include cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol,ethyleneglycolmonomethylether, ethyleneglycolmonoethylether, 2-methoxyethylacetate, 1-methoxy-2-propanol, 1-methoxy-2-propylacetate, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, toluene, ethylacetate, methyl lactate, ethyl lactate, .gamma.-butyrolactone, dioxane and tetrahydrofuran, which may be used alone or in combination.

The polysiloxane compound of the present inventin may be used alone or in combination in the light-sensitive composition. The amount of the polysiloxane compound contained in the light-sensitive composition ranges about 5 to 95 % by weight, preferably about 20 to 80 % by weight.

Specific examples of the polysiloxane compound of the present invention are shown below. ##STR12##

In the above formulas, n is an integer of not less than 1 and x, y and z are integers of 0 or not less than 1.

Examples of iodonium salts of formula (IX) used in the present invention include those disclosed in J.P. KOKAI Nos. Sho 50-158680 and 51-100716 and J.P. KOKOKU No. Sho 52-14277. Specific examples thereof are listed below. ##STR13##

Examples of sulfonium salts of formula (X) are those disclosed in J.P. KOKAI No. Sho. 51-56885J.P. KOKOKU No. Sho. 52-14278, U.S. Pat. Nos. 4,442,197 and 4,760,013 and German Patent No. 2,904,626. Specific examples thereof are listed below: ##STR14##

The compounds represented by the general formulas (IX) and (X) are known and can be prepared, for instance, according to the procedures disclosed in J.W. Knapczyk et al., J. Am. Chem. Soc., 1969, 91, p. 145; A.L. Maycock et al., J. Org. Chem., 1970, 5, p. 2532; E. Goethals et al., Bull. Soc. Chem. Belg., 1964, 3, p. 546; H.M. Leicester, J. Am. Chem. Soc., 1929, 51, p. 587; J. V. Crivello et al., J. Polym. Sci. Polym. Chem. Ed., 980, 18, p. 2677; U.S. Pat. Nos. 2,807,648 and 4,247,473; F. M. Beringer et al., J. Am. Chem. Soc., 1953, 75, p, 2705; and J. P. KOKAI No. Sho 53-101331.

The amount of the iodonium salts or sulfonium salts to be added to the composition ranges from 5 to 70% by weight, preferably 10 to 50% by weight on the basis of the total weight of the solid content of the composition.

The positive working light-sensitive composition of the present invention may comprise simply a combination of the components (a) and (b), but it may further comprise an alkali-soluble polymer.

The alkali-soluble polymers used in the composition are polymers carrying acidic hydrogen atom having pKa of not more than 11 such as phenolic hydroxyl group, carboxyl group, sulfonate residue, imido group, sulfonamido group, N-sulfonylamido group, N-sulfonylurethane group and/or active methylene group. Preferred alkali-soluble polymers are novolak type phenol resins such as phenol-formaldehyde resin, o-cresol-formaldehyde resin, m-cresol-formaldehyde resin, p-cresol-formaldehyde resin, xylenol-formaldehyde resin and co-condensates thereof. It is also possible to simultaneously use the aforesaid phenol resin and a condensate of phenol or cresol substituted with an alkyl group having 3 to 8 carbon atoms with formaldehyde such as t-butylphenol/formaldehyde resin as disclosed in J.P. KOKAI No. Sho 50-125806. Examples of other polymers usable in the invention are polymers comprising phenolic hydroxyl group-containing monomer such as N-(4-hydroxyphenyl) methacrylamide as a copolymerization component; homo- or copolymers of monomer(s) such as p-hydroxystyrene, o-hydroxystyrene, m-isopropenylphenol and/or p-isopropenylphenol and partially etherified or esterified products thereof.

Further, polymers comprising a carboxyl group-containing monomer such as acrylic acid and methacrylic acid as a copolymerization component; carboxyl group-containing polyvinyl acetal resins as disclosed in J.P. KOKAI No. Sho 61-267042; and carboxyl group-containing polyurethane resins as disclosed in J.P. KOKAI No. Sho 63-124047 can suitably be used.

Polymers comprising repeating units derived from monomers such as N-(4-sulfamoylphenyl) methacrylamide, N-phenylsulfonyl methacrylamide and/or maleimide as copolymerization components; and active methylene group-containing polymers as disclosed in J.P. KOKAI No. Sho 63-127237 are also used in the composition of the invention.

These alkali-soluble polymers may be used alone or in combination. The amount of these alkali-soluble polymers to be incorporated into the light-sensitive composition preferably ranges from 10 to 90% by weight, more preferably 5 to 80% by weight on the basis of the total weight of the solid content of the composition.

The positive working light-sensitive composition of the present invention may optionally comprise other additives such as dyes, pigments, plasticizers and compounds for enhancing the decomposition efficiency of the foregoing iodomiun salt or sulfonium salt compounds (so-called sensitizers).

Such sensitizers for the iodomiun salt or sulfonium salt compounds of formulas (IX) and (X) are, for instance, compounds disclosed in U.S. Patent Nos. 4,250,053 and 4,442,197. Specific examples thereof are anthracene, phenanthrene, perylene, pyrene, chrysene, 1,2-benzanthracene, coronene, 1,6-diphenyl-1,3,5-hexatriene, 1,1,4,4-tetraphenyl-1,3-butadiene, 1,2,3,5-tetraphenyl benzene, 2,5-diphenylthiophene, thioxanthone, 2-chlorothioxanthone, phenothiazine, 1,3-diphenyl pyrazoline, 1,3-diphenyl isobenzofuran, xanthone, benzophenone, 4-hydroxybenzophenone, anthrone, ninhydrin, 9-fluorenone, 2,4,7-trinitrofluorenone, indanone, phenanthraquinone, tetralone, 7-methoxy-4-methylcoumalin, 3-keto-bis(7-diethylaminocoumalin), Michler's ketone and ethyl Michler's ketone.

The molar ratio of these sensitizers to the iodomiun salt or sulfonium salt compounds of formulas (IX) and (X) ranges from 0.01/1 to 20/1 and preferably 0.1/1 to 5/1.

In addition, dyes may be used as a coloring agent and preferred dyes include, for instance, oil-soluble dyes and basic dyes. Specific examples thereof are Oil Yellow #101, Oil Yellow #130, Oil Pink #312, Oil Green BG, Oil Blue BOS, Oil Blue #603, Oil Black BY, Oil Black BS, Oil Black T-505 (these dyes being available from ORIENT CHEMICAL INDUSTRIES, LTD.), Crystal Violet (CI 42555), Methyl Violet (CI 42535), Rhodamine B (CI 45170 B), Malachite Green (CI 42000) and Methylene Blue (CI 52015).

The light-sensitive composition of the present invention may further comprise cyclic acid anhydrides and other fillers for further enhancing the sensitivity thereof. Examples of cyclic acid anhydrides are, as disclosed in U.S. Pat. No. 4,115,128, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endoxy- .DELTA..sup.4 -tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, .alpha.-phenylmaleic anhydride, succinic anhydride and pyromellitic anhydride. The sensitivity can be increased as high as about 3 times at maximum by incorporating these cyclic acid anhydride into the composition in an amount of 1 to 15% by weight based on the total weight of the composition.

The positive working light-sensitive composition of the present invention is dissolved in a solvent capable of dissolving the components of the composition and then applied onto the surface of a substrate if it is used as a material for PS plates. In addition, if it is used as a resist for processing semiconductors or the like, it is dissolved in a solvent and the solution is used as such. Examples of such solvents herein used are ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N,N-dimethylacetamide, N,N-dimethylformamide, tetramethyl urea, N-methylpyrrolidone, dimethylsulfoxide, sulforane, .gamma.-butyrolactone, toluene and ethyl acetate and these solvents can be used alone or in combination.

The concentration of the foregoing components (the total solid content inclusive of additives) ranges from 2 to 50% by weight. When the solution is applied onto a substrate, the amount thereof coated varies depending on the appl:,cations and, for instance, as a rule it preferably ranges from 0.5 to 3.0 g/m .sup.2 based on the solid content for PS plates. As the amount thereof coated decreases, the light-sensitivity correspondingly increases, while physical properties of the resultant film are impaired.

When a PS plate is prepared from the positive working light-sensitive composition of this invention, a substrate is in general used and examples thereof include paper, paper laminated with a plastic film such as polyethylene, polypropylene or polystyrene film; a metal plate such as an aluminum (inclusive of aluminum alloys), zinc or copper plate; a plastic film such as a cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate or polyvinyl acetal film; and paper or a plastic film listed above which is laminated with a metal foil or on which a layer of the foregoing metal is deposited. Particularly preferred is an aluminum plate because of its high dimensional stability and low cost. Further, it is also preferred to use a composite sheet comprising a polyethylene terephthalate film on which an aluminum sheet is bonded as disclosed in J.P. KOKOKU No. Sho 48-18327. The surface of the aluminum plate is preferably grained by, for instance, mechanical methods such as wire brush graining, brush graining which comprises graining with a nylon brush with pouring a slurry of abrasive particles, ball graining, graining through liquid honing and buff graining; chemical graining methods such as those in which HF, AlCl.sub.3 or HCl is used as an etchant; electrolytic graining in which nitric acid or hydrochloric acid is used as an electrolyte; or combined graining comprising combinations thereof, then optionally etched with an acid or alkali and anodized in an electrolyte such as sulfuric acid, phosphoric acid, oxalic acid, boric acid, chromic acid, sulfamic acid or a mixture thereof using a DC or AC current to form a strong passivation film on the surface of the aluminum plate. Such a passivation film per se makes the aluminum plate surface hydrophilic, but it is particularly preferred that the aluminum plate is optionally hydrophilized by subjecting it to a silicate (sodium silicate, potassium silicate) treatment as disclosed in U.S. Pat. Nos. 2,714,066 and 3,181,461; a potassium fluorozirconate treatment as disclosed in U.S. Pat. No. 2,946,638; a phosphomolybdate treatment as disclosed in U.S. Patent No. 3,201,247; an alkyl titanate treatment as disclosed in U.K. Patent No. 1, 108,559; a polyacrylic acid treatment as disclosed in German Patent No. 1,091,433; a polyvinyl phosphonic acid treatment as disclosed in German Patent No. 1,134,093 and U.K. Patent No. 1,230,447; a phosphonic acid treatment as disclosed in J.P. KOKOKU No. Sho 44-6409; a phytic acid treatment as disclosed in U.S. Pat. No. 3,307,951; a combined treatment with a hydrophilic organic polymeric compound and a bivalent metal as disclosed in J.P. KOKAI Nos. Sho 58-16893 and Sho 58- 18291; a treatment by means of an underlying coating of an water-soluble polymer having sulfonate groups as disclosed in J.P. KOKAI No. Sho 59-101651. Examples of other hydrophilization treatments are silicate electrodeposition treatments as disclosed in U.S. Pat. No. 3,658,662.

It is also preferred to use an aluminum plate which is subjected to a sealing treatment after graining and anodization treatments. Such a sealing treatment can be performed by immersing the aluminum plate in hot water or a hot aqueous solution containing an inorganic or organic salt or by means of a steam bath.

Light sources for actinic rays or radiant rays used in the present invention are, for instance, a mercury lamp, a metal halide lamp, a xenon lamp, a chemical Iamp and a carbon arc lamp for actinic rays and electron rays, X-rays, ion beam and far ultraviolet rays for radiant rays. Preferred examples of light sources are g-rays, i-rays and Deep-UV rays for photoresists. In addition, a scaning exposure technique with a high energy density beam such as laser beam or electron rays can be employed in the invention. Examples of such laser beam sources are a He.multidot.Ne laser, an Ar laser, a Kr ion laser, a He.multidot.Cd laser and KrF excimer laser.

Examples of developers for the positive working light-sensitive composition of the present invention preferably include an aqueous solution of an inorganic alkali agent such as sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tertiary sodium phosphate, secondary sodium phosphate, tertiary ammonium phosphate, secondary ammonium phosphate, sodium metasilicate, sodium bicarbonate or ammonia or an organic alkali agent such as tetraalkyl ammonium hydroxide. These alkaline agents may be used alone or in combination. The concentration thereof ranges from 0.1 to 10% be weight and preferably 0.5 to 5% by weight.

These aqueous alkali solutions may optionally comprise a surfactant or an organic solvent such as an alcohol.

The present invention will hereunder be explained in more detail with reference to the following non-limitative working Examples and the effects practically achieved by the present invention will also be discussed in detail.

Maleimide (7.3g) and 2-trimethoxysilyl-1,3-butadiene (13.lg) were dissolved in 500 ml of dioxane. The mixture was kept at 100 .degree. C. for one hour. To the reaction mixture, phenyltriethoxysilane (102g) was added and then 10 ml of distilled water and 0.2 ml of hydrochloric acid were added. The mixture was heated and cocentrated for 30 minutes. The concentrate was poured into 2000 ml of distilled water while stirring. The precipitated solid was dried in vacuo to obtain 51g of the target polysiloxane.

The weight average molecular weight of the polysiloxane was found 1200 by Gel Permeation Chromatography.

Acetylene dicarboxylic acid (11.4g), 2-trimethoxysilyl-1,3-butadiene (17.4g) and tolyltrimethoxysilane (122.6g) were reacted in dioxane in the same manner as in Preparation Example 1 to obtain 43g of the target polysiloxane.

The weight average molecular weight of the polysiloxane was found 8600 by Gel Permeation Chromatography.

N-(p-hydroxyphenyl)maleimide (18.9g) and 1-trimethoxysilyl-1,3-butadiene (17.4g) were reacted in 500ml of ethyleneglycol monomethylether in the same manner as in Preparation Example 1 to obtain 18g of the target polysiloxane.

The weight average molecular weight of the polysiloxane was found 3300 by Gel Permeation Chromatography.

N-(p-sulfamoyl)maleimide (25.2g) and 2-trimethoxysilyl-1,3-butadiene (17.4g) were reacted in 500ml of N,N-dimethylacetamide in the same manner as in Preparation Example 1 to obtain 36g of the target polysiloxane.

The weight average molecular weight of the polysiloxane was found 2300 by Gel Permeation Chromatography.

N-(p-toluensulfonyl)acrylamide (22.5g), 2-trimethoxysilyl-1,3-butadiene (17.4g) and 4-chlorophenyltrimethoxysilane (64g) were reacted in 500ml of ethyleneglycol monomethylether in the same manner as in Preparation Example 1 to obtain 40g of the target polysiloxane.

The weight average molecular weight of the polysiloxane was found 4700 by Gel Permeation Chromatography.

Acetoacetoxyethylacrylate (10.0g), 1-trimethoxysilyl-1,3-butadiene (17.4g) and N-phenylacrylamide (8.4g) were reacted in dioxane in the same manner as in Preparation Example 1 to obtain 25.lg of the target polysiloxane.

The weight average molecular weight of the polysiloxane was found 1700 by Gel Permeation Chromatography.

A 2S aluminum plate having a thickness of 0.24 mm was immersed in 10% aqueous solution of tertiary sodium phosphate maintained at 80.degree. C for 3 minutes to degrease the same, grained with a nylon brush, etched with a sodium aluminate solution for about 10 minutes and then desmutted with a 3% aqueous solution of sodium hydrogen sulfate. The aluminum plate was then anodized at a current density of 2 A/dm.sup.2 for 2 minutes in a 20% sulfuric acid solution to thus obtain an aluminum substrate.

Six kinds of solutios, (A)-1 to (A)-6, of light-sensitive composition (hereunder referred to as "light-sensitive solutions") were prepared by changing the kinds of polysiloxane compounds of the present invention used in light-sensitive solution (A) having the following composition. Each of these light-sensitive solutions was applied to the anodized aluminum plate and dried at 100 .degree. C. for 2 minutes to obtain PS plates (A)-1 to (A)-6, respectively. The coated amount of the light-sensitive sensitive solution was 1.5 g/m.sup.2 (weighed after drying) in all the PS plates.

The polysiloxane compounds used in the light-sensitive solutions (A)-1 to (A)-6 are listed in Table I given below.

A gray scale having a density difference of 0.15 was brought in close contact with the light-sensitive layer of each PS plate (A)-1 to (A)-6 and the layer was exposed to light from a 2 KW high pressure mercury lamp at a distance of 50 cm for 2 minutes. The exposed PS plates (A)-1 to (A)-6 were immersed in and developed with DP-4 (a tradename of the developer available from Fuji Photo Film Co., Ltd.) diluted 8 times with water for seconds at 25.degree. C to thus obtain positive images dyed clear blue.

Each of light-sensitive solutions (A')-1 to (A')-6 which had the same compositions as those of the light-sensitive solutions (A)-1 to (A)-6 used in Examples 1 to 6 except that Oil BLue #603 was removed was applied to a silicon wafer with a spinner and dried on a hot plate maintained at 90.degree. C. for 2 minutes. The thickness of the layer was 1.0 .mu.m.

Then the resultant light-sensitive layer was exposed to light with a scale down projection aligner (stepper) using monochromatic light of 436 nm and was developed with a 2.4% aqueous solution of tetramethyl ammonium hydroxide for 60 seconds to form a resist pattern. As a result, a good pattern having a line & space of 0.8.mu.m was obtained.

A commercially available novolak type resist HPR-204 (available from Fuji Hunt Chemical Co., Ltd.) was applied to a silicon wafer with a spinner and dried at 220 .degree. C for one hour to form an underlying coating. The thickness thereof was 2.0 .mu.m.

The following light-sensitive solution (B) was applied to the underlying layer with a spinner and dried on a hot plate maintained at 90 .degree. C. for 2 minutes to form a coated film having a thickness of 0.5 .mu.m.

The resulting light-sensitive layer was exposed to light and developed in the same manner as used in Examples 7 to 12 and as a result, a good pattern having a line & space of 0.8.mu.m was obtained. Then the layer was subjected to an oxygen plasma etching under the conditions of 20 mTorr of O.sub.2 gas pressure and 0.06 W/cm.sup.2 of RF power. The lower resist which was not covered by the resist pattern was completely eliminated. Thus, it was confirmed that the resist of the invention could be used as an upper resist in the two layer resist technique.