GB2216532A

GB2216532A - Heat resistant and photosensitive aromatic polyamide resins and method of preparing same

Info

Publication number: GB2216532A
Application number: GB8904786A
Authority: GB
Inventors: Tsuguo Yamaoka; Yutaka Maruyama; Kentaro Tsutsumi; Haruhiko Komoriya
Original assignee: Central Glass Co Ltd
Current assignee: Central Glass Co Ltd
Priority date: 1988-03-03
Filing date: 1989-03-02
Publication date: 1989-10-11
Anticipated expiration: 2009-03-02
Also published as: IT8919593A0; FR2628112A1; IT1228515B; GB8904786D0; DE3906684A1; GB2216532B; FR2628112B1

Description

221 ú 532 HEAT RESISTANT AND PHOTOSENSITIVE AROMATIC POLYAMIDE RESINS AND

METHOD OF PREPARING SAME This invention relates to a group of novel aromatic aromatic polyamide resins, which have-heat resistance and photosensitivity or radiation sensitivity and hence are useful as photosensitive materials for forming patterns in electronic devices, and a method of preparing the novel polyamide resins.

In the field of semiconductor devices, thermally stable inorganic materials have been used as insulating layers and passivation layers in solid-state components.

However, inorganic materials suitable for-such uses are generally poor in flexibility or pliability and, rather, are brittle In recent years trials have been made to use organic resins high in heat resistance such as polyimide resins in place of the inorganic materials.

Polyimide resins are chemically stable and resistant to heat to the extent of 3000 C or above.

Besides, polyimide resins are adequately flexible.

Therefore, polyimide resins are suitable for use in forming insulating or protective layers in electronic devices Also there are proposals of using a polyimide resin as the basic material of a layer in which a pattern is to be formed by a photolithography technique.

Since polyimide resins do not possess photosensitivity or radiation sensitivity, it is necessary to use a mixture of a polyimide resin and a photosensitive compound However, such a mixture is insufficient in storability as a photosensitive material for practical use, and the mixing is liable to mar the excellent properties inherent to the polyimide resin.

DE 1,764,977 shows a method of forming a relief pattern of a polyimide resin by the steps of overlaying a polyimide precursor (polyamic acid) layer with a conventional photoresist layer, forming a pattern in the resist layer by a photolithography technique, eluting the polyimide precursur layer in areas where the resist layer disappeared, then removing the patterned resist layer and heat-treating the remaining areas of the poly- imide precursor layer However, this method is not favorable for industrial practice because of including many steps.

It is an object of the present invention to provide novel aromatic polyamide resins which are resistant to heat and possess photosensitivity or radiation sensitivity.

It is another object of the invention to provide a method of preparing aromatic polyamide resins of the invention.

The present invention provides aromatic polyamide resins having repeating units represented by the general formula ( 1):

R 3 R 4 O O \ N-R -N-C-R 1 1 _ CR 3 ( 1) 1 3 C 4- wherein R is an aromatic group, each of R 3 and R 4 is hydrogen atom or an aliphatic or aromatic group which has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray, and R 2 is an aliphatic or aromatic group and, when both R 3 and 4.

R in each repeating unit are hydrogen atoms, has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray.

Furthermore, this invention provides aromatic polyamide resins having repeating units represented by the general formula ( 2):

/R 3 R 4 o o \ I 1 1 11 2 II N-R N-C-R -C ( 2) R 5 / \R 6 RO O OR wherein R 1, R, R 3 and R 4 are as defined above, each of R 5 and R 6 is hydrogen atom or an aliphatic or aromatic group which has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray, and each of -OR 5 and -OR 6 is at the ortho or periposition with respect to amido group.

In the novel polyamide resins having repeating units of the general formulas ( 1) or ( 2) the aromatic group R 1 is, for example, phenylene group (hereafter (Ph) represents phenylene group), -(Ph)-(Ph)-, -(Ph)-O-(Ph)-, -(Ph)-CO-(Ph)-, -(Ph)-502-(Ph)-, -(Ph)-CH 2-(Ph)-, -(Ph)-C(CH 3)2-(Ph)-, -(Ph)-C(CF 3)2- (Ph)-, (Ph)-O-(Ph)-C(CH 3)2-(Ph)-O-(Ph)-, or -(Ph)-O- C(CF 3)2-(Ph)-O-(Ph)-.

Preferably R 2 in the general formula ( 1) or ( 2) is an aromatic group such as, for example, -(Ph)-, -(Ph)-(Ph)-, -(Ph)-O-(Ph)-, -(Ph)-CO-(Ph)-, (Ph)-CH 2- (Ph)-, -(Ph)-C(CH 3)2-(Ph)-, -(Ph)-C(CF 3)2-(Ph) or -(Ph)-CO-(Ph)-.

/ HOOC COOH A typical example of R and R in the general formula ( 1) or ( 2) and R 5 and R 6 in the general formula ( 2) is -CO-C(CH 3)=CH 2.

Aromatic polyamide resins of the invention include those which have repeating units represented by the following general formula ( 1 A) or ( 2 A).

H HO O L -R 1 I Il211 _ N-R N-C-R -C ( 1 A) H HO O I l l ll R 211 N ( 2 A) 2 ON-R-/RN-C-R -C ( 2 A) HO OH As noted hereinbefore, R 2 in these formulas ( 1 A), ( 2 A) represents an aliphatic or aromatic group which has at least one carbon-to-carbon double bond and is dimeriz- able or polymerizable by an energetic ray.

Preferably the aromatic group R 1 in the formula ( 1 A) has at least one perfluoroalkyl group For example, R is -(Ph)-CC 6 H 5 CF 3-(Ph)-, -(Ph)-C(CF 3)2-(Ph)-, -(Ph)-O-(Ph)-CC 6 H 5 CF 3-(Ph)-O-(Ph) or -(Ph)-O-(Ph)- C(CF 3)2-(Ph)-O-(Ph)-.

Good examples of R 2 in the formulas ( 1 A) and ( 2 A) are -CH=CH-, -CH=CH-(Ph)-CH=CH-, -(Ph)-CH=CH and -(Ph)-CO-CH=CH-(Ph)-.

An aromatic polyamide resin of a structure repre- sented by the general formula ( 1) or ( 2) is obtained by reacting an aromatic diamine represented by the follow- ing general formula ( 3) or ( 4) with a dicarboxylic acid having the aliphatic or aromatic group R 1, or its dihalide or diester, or a di or tetracarboxylic acid anhydride having the group R 2: R 3-NH-R 1-NH-R 4 ( 3) wherein R 1, R 3 and R 4 are as defined hereinbefore, R 3 _-NH-R 1 _NH-R 4 ( 4) \ 6 R 5 o/ \o R 6 wherein R 1 R 3, R 4, R 5 and R 6 are as defined herein- before, and each of -OR 5 and -OR 6 is at the ortho or peri-position with respect to amido group.

The invenation provides another method of preparing an aromatic polyamide resin of a structure represented by the general formula ( 1), with proviso that neither of R 3 and R 4 is hydrogen atom The method comprises reacting a polymer having repeating units represented by the general formula ( 5) with an at least one compound which has at least one carbon-to-carbon double bond, is dimerizable or polymerizable by an energetic ray and selected from carboxylic acids, carboxylic acid derivatives and epoxides:

N -R -N-C-R -C ( 5) wherein R 1 and R are as defined hereinbefore.

The invention includes preparing an aromatic poly- amide resin of a structure represented by the general I 34 5 6 formula ( 2), with proviso that any of R, R R and R is not hydrogen atom, by reacting a polymer having repeating units represented by the general formula ( 6) with at least one compound which has at least one carbon-to-carbon double bond, is dimerizable or polymer- izable by an energetic ray and selected from carboxylic acids, carboxylic acid derivatives and epoxides:

/ H HO O \ / I 1 I II 2 Il N -R -N -C-R -C( 6) __/\ /'.

HO OH wherein R 1 and R 2 are as defined hereinbefore, and each hydroxyl group is at the ortho or peri-position with respect to amido group.

Aromatic polyamide resins according to the invention have good mechanical properties and are high in heat resistance, and these polyamide resins are soluble in many kinds of organic solvents Accordingly the novel polyamide resins are useful in, for example, for forming insulating layers and protective layers in semiconductor devices Furthermore, the novel polyamide resins have photosensitivity and become hardly soluble by exposure to an energetic ray such as X-ray, electron beam, ultraviolet ray or visible ray Therefore, these polyamide resins serve as photosensitive materials without need of adding any sensitizer and are usuful for forming relief patterns in semiconductor devices and printed circuits for instance Optionally a known sensitizer or photopolymerization initiator may be added to a photosensitive polyamide resin of the invention.

In preparing an aromatic polyamide resin of the invention from a polymer of a structure represented by the general formula ( 5) or ( 6), the starting polymer can be selected from various polymeric compounds having amido group containing active hydrogen such as, for example, aromatic polyamides, aromatic polyimide precursors (viz, aromatic polyamic acids), polybenzo- imidazole precursors, polybenzoxazole precursurs, polybenzoxazinone precursors and polyquinazolone precursors.

A selected polymer of the formula ( 5) or ( 6) is reacted with at least one carboxylic acid, which has at least one carbon-to-carbon double bond and is dimeriz- able or polymerizable by an energetic ray, or its derivative such as halide, ester or anhydride, or an epoxide The carboxylic acid or its derivative can be selected, for example, from acrylic acid, methacrylic acid, chlorides, alkyl esters, phenyl esters, hydroxy- alkyl esters and methoxyalkyl esters of acrylic and methacrylic acids, cinnamic acid, cinnamic acid chloride, cinnamic acid methyl ester, glycidyl acrylate, glycidyl methacrylate, glycidyl cinnamate, hydroxyvinyl ether, chloroethylvinyl ether and maleic anhydride.

The reaction between the polymer and the carboxylic acid or its derivative, or epoxide, is carried out in an organic solvent such as N,N-dimethylformamide, N,N- dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, tetrahydrofuran or cyclohexanone at a temperature ranging from about -20 C to the boiling point of the employed solvent The reaction proceeds fairly rapidly and is completed in several minutes to several hours.

Optionally a suitable additive or catalyst may be used for enhancement of the rate of reaction For example, when a carboxylic acid chloride is reacted, addition of triethylamine or pyridine is effective for removal of by-produced hydrogen chloride When an epoxide is reacted, it is effective to use a catalyst selected from amines represented by triethylamine and quaternary onium salts such as benzyltriethylammonium chloride and benzyltriphenylphosphonium chloride.

Another way of preparing an aromatic polyamide of a structure represented by the general formula ( 1) or ( 2) is reacting an aromatic diamine represented by the general formula ( 3) or ( 4) with a dicarboxylic acid, or its dihalide or diester, or a di or tetracarboxylic acid anhydride When the polyamide to be prepared is of a structure represented by the general formula ( 1 A) or ( 2 A), this way is necessarily taken.

Examples of aromatic diamines represented by the general formula ( 3) are paraphenylenediamine, metaphenylenediamine, 4,4 '-diaminodiphenyl ether, 3,3 '- diaminodiphenyl ether, 3,4 '-diaminodiphenyl ether, 3,3 'diaminodiphenylmethane, 4,4 '-diaminodiphenylmethane, 3,3 '-diaminodiphenylketone, 4,4 '-diaminodiphenylketone, 2,2-bis( 4-aminophenyl)propane, 2,2-bis( 3-aminophenyl)- propane, 3,3 '-diaminodiphenylsulfone, 4,4 '-diamino- diphenylsulfone, 2,2-bis( 4-aminophenyl)hexafluoro- propane, 2,2-bis( 3-aminophenyl)hexafluoropropane, 2,2- bisl 4-( 4-aminophenoxy)phenyllpropane, 2,2-bisl 4-( 4aminophenoxy)phenyllhexafluoropropane, 2,2-bisl 4-( 3aminophenoxy)phenyllhexafluoropropane, 2,2-bis( 3-amino4-methylphenyl)hexafluoropropane, 1-trifluoro-2-phenyl- 2,2-bis( 4-aminophenyl)ethane, 1-trifluoro-2-phenyl-2,2- bisl 4-( 4-aminophenoxy)phenyllethane, 1-trifluoro-2- phenyl-2,2-bisl 4-( 3-aminophenoxy)phenyllethane, 2,2-bis- l 3-methyl-4-( 4-aminophenoxy)phenyllhexafluoropropane and 2,2-bisl 3-bromo-4-( 4-aminophenoxy)phenyllhexafluoro- propane If desired, two or more kinds of aromatic diamines may be used jointly.

Examples of aromatic diamines represented by the general formula ( 4) are 2,2-bis( 3-amino-4-hydroxy- phenyl)propane, 2,2-bis( 3-amino-4-hydroxyphenyl)hexa- fluoropropane, 3,3 '-diamino-4,4 '-dihydroxybiphenyl, 4,4 '-diamino-3,3 '-dihydroxybiphenyl, bis( 3-amino-4- hydroxyphenyl)sulfone, 3,3 '-diamino-4,4 '-dihydroxybenzophenone, bis( 3-amino-4-hydroxyphenyl)methane, bis( 3-amino-4-hydroxyphenyl)ether, bis( 3-amino-4- hydroxyphenyl)sulfide, 1,4-diamino-2,5-dihydroxy- benzene, 1,5-diamino-2,4-dihydroxybenzene, 1-phenyl-1,1- bis( 3-amino-4-hydroxyphenyl)ethane, 1-phenyl-1,1-bis( 3amino-4-hydroxyphenyl)trifluoroethane, 1-trifluoro- methyl-1,1-bis( 3-amino-4-hydroxyphenyl)ethane, 1,1,3- trimethyl-3-( 3 '-amino-4 '-hydroxy)-5-hydroxy-6-amino- indan and 3,3 '-diamino-4,4 '-dihydroxyterphenyl.

A dicarboxylic acid or its derivative to be reacted with a selected aromatic diamine is represented by the general formula ( 7):

O O X-C-R -C-X ( 7) wherein R 2 is as defined hereinbefore, and X represents hydroxyl group, a halogen atom or -OR' group wherein R' is an alkyl group or a phenyl group.

When the aromatic diamine has at least one substi- tution, i e when at least one of R 3 and R 4 in the general formula ( 3) or ( 4) is not hydrogen atom, good examples of the reactant represented by the general formula ( 7) are isophthalic acid, terephthalic acid, bipnenylether-4,4 '-dicarboxylic acid, benzophenone-4,4 '- dicarboxylic acid, biphenyl-4,4 '-dicarboxylic acid, biphenylsulfone-4,4 '-dicarboxylic acid, 2,6-naphthalene- dicarboxylic acid, diphenylmethane-4,4 '-dicarboxylic acid, isopropylidenebiphenyl-4,4 '-dicarboxylic acid and hexafluoroisopropylidenebiphenyl-4,4 '-dicarboxylic acid, dichlorides of these dicarboxylic acids, dimethyl esters of these dicarboxylic acids and diphenyl esters of these dicarboxylic acids If desired two or more kinds of dicarboxylic acids or their derivatives may be used jointly.

The reaction of the selected aromatic diamine and the selected dicarboxylic acid or its derivative is carried out in an organic solvent such as N,N-dimethyl- formamide, N,N-dimethylacetamide or N-methyl-2pyrrolidone In the case of a dicarboxylic acid or its dichloride the reaction is carried out at a temperature ranging from about -10 C to about 50 C In the case of a dicarboxylic acid diester a suitable range of the reaction temperature is from about 500 C to about 3000 C.

It is possible to use a tetracarboxylic acid anhydride represented by the following general formula ( 8) in place of a dicarboxylic acid or its dichloride or diester described above.

O O II II 0 R 2 O ( 8) \C C 11 11 II II 0 O wherein R 2 is as defined hereinbefore.

For example, the acid anhydride is selected from 4,4 '-oxydiphthalic acid anhydride, 2,2-bis( 3,4- dicarboxyphenyl)hexafluoropropane dianhydride, 2,2- bisl 4-( 3,4-dicarboxyphenoxy)phenyllhexafluoropropane dianhydride, 3,3 ',4,4 '-benzophenonetetracarboxylic acid dianhydride, pyromellitic acid dianhydride and 3,3 ',4,4 '-biphenyltetracarboxylic acid dianhydride.

The reaction of the selected aromatic diamine with an acid anhydride is carried out in an organic solvent of the aforementioned type at a temperature ranging from about -10 C to about 100 C.

When the aromatic diamine has no substitutiton, i.e when both R 3 and R 4 in the general formula ( 3) or ( 4) are hydrogen atoms, good examples of the reactant represented by the general formula ( 7) are fumaric acid, maleic acid, paraphenylenediacrylic acid, carboxy- cinnamic acid and dicarboxychalcone, dichlorides of these dicarboxylic acids, and dimethyl, diethyl and diphenyl esters of these dicarboxylic acids.

The reaction of the selected aromatic diamine with the selected dicarboxylic acid or its derivative is carried out in an organic solvent such as N,N-dimethyl- formamide, N,N-dimethylacetamide, N-methyl-2pyrrolidone, dimethylsulfoxide or pyridine In the case of a dicarboxylic acid the reaction is carried out at a temperature ranging from room temperature to the boiling point of the employed solvent In the case of an acid dihalide the reaction temperature ranges from about -10 C to about 100 C, and in the case of an acid diester from about 50 C to about 3000 C.

It is possible to use a dicarboxylic acid anhydride represented by the following general-formula ( 9) in place of a dicarboxylic acid or its dichloride or diester described above For example, maleic anhydride is useful Also in this case the reaction is carried out in an organic solvent of the above described type at a temperature ranging from room temperature to the boiling point of the solvent.

O O IL 2 1 I C-R C ( 9) wherein R 2 is as defined hereinbefore.

In an aromatic polyamide resin of a structure represented by the general formula ( 1), the group R 2 may be an aromatic group of the type represented by the following general formula ( 10):

2 ' R 2 ' xo-c C-OX ( 10) II II O O R 2 ' wherein R 2 is an aromatic hydrocarbon group, X is hydrogen atom, an alkyl group or a phenyl group, and each -COOX group is at the ortho or peri-position with respect to amido group in the general formula ( 1).

Then the polyamide undergoes a cyclizing reaction by a heat treatment or a suitable chemical treatment and turns into a polyimide, which has repeating units represented by the following general formula ( 11) and is better in heat resistance than the polyamide:

O O II II C C O O R N / R x \ ( 1 C C" 0 0 wherein R 1 and R 2 are as defined hereinbefore.

An aromatic polyamide of a structure represented by the general formula ( 2) undergoes a cyclizing reaction by a heat treatment or a suitable chemical treatment and turns into a polybenzoxazole, which has repeating units represented by the following general formula ( 12) and is better in heat resistance than the polyamide:

/ \o/ -2} tC \ R \ \ C R 2 t ( 12) wherein R 1 and R 2 are as defined hereinbefore.

When an aromatic polyamide resin of the invention is used as a photosensitive material, usually the resin is dissolved in a suitable organic solvent to apply the resin to a substrate by a wet coating method Since the polyamide resin itself has photosensitivity it is not necessary to add a sensitizer to the resin or its solution However, according to the need it is free to prepare a photosensitive composition by adding a sensitizer or a photopolymerization initiator to the poly- amide solution, and any other auxiliary agent may optionally be added For example, a monomer copolymer- izable with the polyamide resin and/or an adhesive aid may be added The solvent is selected so as to dissolve optional additive(s) together with the polyamide resin and can be selected from various and widely used polar solvents Examples of suitable solvents are N,Ndimethylformamide, N,N-dimethylacetamide, N-methyl-2- pyrrolidone, dimethylsulfoxide, tetrahydrofuran and cyclohexanone.

Examples of useful sensitizers and photopolymeri- zation initiators are benzophenone, N,N'-tetramethyl- 4,4 '-diaminobenzophenone (Michler's ketone), 4,4 '-bis- (diethylamino)benzophenone, acetophenone, trichloroacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1diethoxy-1-acetophenone, 4 '-methylthio-1,1-dimethyl-1morpholinoacetophenone, 2-hydroxy-2-methylpropiophenone, methylbenzoylformate, benzoyl ether, 2-t-butyl-9,10- anthraquinone, 1,2-benzo-9,10-anthraquinone, N-methyl1,2-naphthothiazoyl-2,2-dibenzoylethylene, xanthone, thioxanthone, 2-chlorothioxanthone, benzil, benzyl- dimethyldithiocarbamate, 1-phenyl-1,2-propanedion-2- (o-benzoyl)oxime, 5-nitroacenaphthene and chloro- hydroxybenzoanthrone.

A copolymerizable monomer can be selected from, for example, monomaleimide, polymaleimide, acrylic acid and methacrylic acid, and their derivatives.

In the case of adding an adhesive aid for improving adhesion of a photosensitive material according to the invention to various substrates, it is suitable, though not limitative, to use an organosilicon compound such as vinyltriethoxysilane, vinyltrimethoxysilane or methacryloxypropyltrimethoxysilane.

Using a conventional photolithography technique, a pattern can be formed in a film of a photosensitive material according to the invention The film is formed by applying the photosensitive material in the form of solution to a substrate by a suitable method such as spin coating method After drying a negative mask is placed on the coating film, and the film is exposed to an energetic ray such as, for example, X-ray, electron ray, ultraviolet ray or visible ray Then the masked areas of the film are removed by dissolving in a developer liquid to thereby form a relief pattern in the film As the developer liquid, usually a mixture of a good solvent for the photosensitive material and a bad solvent for same is used For example, the good solvent is dimethylformamide, dimethylacetamide, dimethyl- sulfoxide, N-methylpyrrolidone, tetrahydrofuran or cyclohexanone, and the bad solvent is methanol, ethanol, ethyl acetate, isoamyl acetate or methyl cellosolve.

It is possible to further enhance the heat resist- ance of a relief pattern formed by the above process by making a suitable heat treatment or chemical treatment on the relief pattern It is possible to obtain a relief pattern which does not dull and does not exhibit loss of weight until the temperature nears 4000 C to about 4000 C.

Aromatic polyamide resins of the invention are excellent in mechanical properties, insulating charac- teristics, dielectric characteristics, weatherability and moisture-proofness, besides photosensitivity and heat resistance Accordingly the polyamide resins are useful, for example, for forming protective layers or passivation layers in semiconductor devices, insulating layers in integrated circuits and protective layers on soldered connections in printed circuits Besides, the polyamide resins will serve as highly heat resistant photoresists in physical vapor deposition processes or dry etching processes.

The invention is further illustrated by the following nonlimitative examples.

EXAMPLE 1

In a 100-ml flask of egg-plant type, 5 19 g of 2,2- bisl 4-( 4-aminophenoxy)phenyllhexafluoropropane was dissolved in 25 ml of dimethylacetamide In a nitrogen gas atmosphere the solution was completely freezed by using a bath of dry ice and acetone, and then 2 55 g of p-phenylenediacrylic acid dichloride was added After that the bath was changed to an ice bath, and stirring was continued for 6 hr while maintaining a nitrogen gas atmosphere in the flask After that the reaction liquid was poured into 200 ml of methanol to precipitate a polymer Analysis of the polymer gave the following results.

Infrared Absorption Spectrum (sample in film form) 1660 cm-1 ( C= 0) 1620 cm-1 ( C=C) 1240 cm-1 ( 50) 1180 cm-1 () C-F) -1 1050 cm (aromatic C=C) Elementary Analysis Calculated (%): C 66 86, H 3 74, N 9 13 Found (%): C 66 49, H 3 63, N 9 17 The obtained polymer was confirmed to be a polyamide having repeating units of the following formula.

Intrinsic viscosity Linh of the polyamide was 1 16 d L/g in dimethylacetamide at 30 O C.

CF 3 0 O t HN t D-O-g O N NHC CH CH CH=CH-C CF 3 The obtained polyamide was tested as a photo- sensitive material for forming a relief pattern.

A solution was prepared by dissolving 10 parts by weight of the above polyamide in 100 parts by weight of N-methyl-2-pyrrolidone and then adding 0 5 parts by weight of Michler's ketone The solution was coated on a silicon wafer with a spinner, and drying was made at C for 1 hr to obtain a polymer coating film having a thickness of 0 5,sm A photomask was placed closely on the polymer film, and exposure was made for 1 min with a 450-W high-pressure mercury lamp at a distance of 30 cm.

Then development was made by using tetrahydrofuran to thereby form a relief pattern in the polymer film The rerief pattern was kept heated at 300 C for 1 hr, but neither dulling of the pattern nor loss of weight was observed.

EXAMPLE 2

As a photosensitive material, a solution was prepared by dissolving 10 parts by weight of the poly- amide prepared in Example 1 and 0 5 part by weight of chlorohydroxybonzoanthrone in 100 parts by weight of N-methyl-2-pyrrolidone The solution was coated on a silicon wafer in the same manner as in Example 1, and the resultant coating film was exposed in the same manner as in Example 1 In this case methyl cellosolve was used as developer As the result a relief pattern having good resistance to heat was obtained.

EXAMPLE 3

The process of Example 2 was repeated except that 0 5 part by weight of 2,2-diethoxyacetophenone was used in place of chlorohydroxybenzoanthrone and that a mixed liquid of 5 parts by weight of cyclohexanone and 3 parts by weight of ethanol was used as developer Also in this case a relief pattern good in heat resistance was formed.

EXAMPLE 4

In a 100 ml flask of egg-platnt type, 4 32 g of 3,3 '-dihydroxy-4,4 '-diaminobiphenyl was dissolved in ml of dimethylacetamide The solution was completely freezed by using a bath of dry ice and acetone, and then 5.10 g of p-phenylenediacrylic acid dichloride was added.

After that the bath was changed to an ice bath, and stirring was continued for 8 hr Then the reaction liquid was poured into 200 ml of methanol to precipitate a polymer Analysis of the polymer gave the following results.

Infrared Absorption Spectrum (sample in film form) 3100 cm 1 (' OH) 1660 cm-1 ( C=O) 1620 cm-1 ( C=C) 1050 cm-1 (aromatic C=C) Elementary Analysis Calculated (%): C 72 35, H 4 55, N 7 03 Found (%): C 72 11, H 4 53, N 7 09 The obtained polymer was confirmed to be a poly- amide having repeating units of the following formula.

Intrinsic viscosity 'inh of the polyamide was 1 02 d L/g in dimethylacetamide at 30 C.

HO OH 00 \ t HN Nn C-Cn=CH e _CH=CH-C For testing, a solution was prepared by dissolving parts by weight of the obtained polyamide and 0 5 part by weight of Michler's ketone in 90 parts by weight of N-methyl-2-pyrrolidone The solution was coated on a silicon wafer with a spinner, and drying was made at C for 3 min The resultant coating film had a thick- ness of 1 Alm A photomask was placed closely on the coating film, and exposure was made for 10 min with a 450-W high-pressure mercury lamp at a distance of 30 cm.

Then development was made with a mixed liquid of 80 wt% of cyclohexanone and 20 wt% of methyl cellosolve As the result a relief pattern was formed in the polymer film To convert the polyamide into a corresponding polybenzoxazole, the patterned film was subjected to heat treatment at 300 C for 5 min After that the relief pattern was heated nearly to 400 C, but neither dulling of the pattern nor loss of weight was observed.

EXAMPLE 5

A polyamide having repeating units of the following formula was prepared by reacting 7 32 g of 2,2-bis( 3- amino-4-hydroxyphenyl)hexafluoropropane with 5 10 g of p-phenylenediacrylic acid dichloride by the same method as in Example 4.

CF 3 0 0 H Nf C NC-CH=CHDCH=CH-C Intrinsic viscosity linh of the polymer was 1 20 d L/g in dimethylacetamide at 30 O C.

Infrared Absorption Spectrum (sample in film form) 3100 cm-1 () OH) 1660 cm 1 ( 9 C=O) -1 1620 cm ( 9 C=C) -1 1180 cm ( 9 C-F) -1 1050 cm 1 (aromatic C=C) Elementary Analysis Calculated (%): C 59 13, H 3 31, N 5 11 Found (%): C 59 05, H 3 33, N 5 19 A solution was prepared by dissolving 10 parts by weight of the obtained polyamide and 0 5 part by weight of Michler's ketone in 90 parts by weight of methyl cellosolve The solution was coated on a silicon wafer in the same manner as in Example 4, and exposure was made in the same manner as in Example 4 In this case a mixed liquid of 80 wt% of cyclohexanone and 20 wt% of methyl cellosolve was used as developer As the result a relief pattern was formed in the polymer film By heat treatment at 3000 C for 5 min, the relief pattern became resistant to heat up to about 400 C.

EXAMPLE 6

A solution was prepared by dissolving 10 parts by weight of the polyamide obtained in Example 5 and 0 5 part by weight of 5-nitroacenaphthene in 90 parts by weight of methyl cellosolve Using this solution, the coating, exposing and developing process of Example 4 was repeated Also in this case a relief pattern was formed in the polymer film, and by the aforementioned heat treatment the relief pattern became resistant to heat up to about 400 C.

EXAMPLE 7

The solution of Example 6 was modified by using 0.5 part by weight of N-methyl-1,2-naphthothiazole-2,2- dibenzoylethylene in place of 5-nitroacenaphthene.

Using the modified solution, the coating and exposure operations inExample 4 were repeated, and development was made with a mixed liquid of 30 wt% of methyl cello- solve and 70 wt% of isoamyl acetate Also in this case a relief pattern was formed in the polymer film, and by the aforementioned heat treatment the relief pattern became resistant to heat up to about 400 C.

EXAMPLE 8

A solution was prepared by dissolving 10 parts by weight of the polyamide prepared in Example 5, 0 5 part by weight of Michler's ketone and 1 part by weight of bismaleimide in 90 parts by weight of N-methyl-2- pyrrolidone Using this solution, the coating, exposing and developing process of Example 4 was repeated Also in this case a relief pattern was formed in the polymer film, and by the aforementioned heat treatment the relief pattern became resistant to heat up to about 400 C.

EXAMPLE 9

The solution of Example 8 was modified by omitting Michler's ketone and using 3 parts by weight of 2,2- bisl 4-( 2-ethoxyethoxy)phenyllpropanediacrylate in place of bismaleid Using the modified solution the coating ane exposure operations in Example 4 were repeated, and development was made with a mixed liquid of 40 wt% of cyclohexanone and 60 wt% of isoamyl acetate Also in this case a relief pattern was formed in the polymer film, and the relief pattern became resistant to heat up to about 400 C by the same heat treatment as in Example EXAMPLE 10

In a 500 ml three-necked flask provided with a dropping funnel, thermometer and stirrer, 7 52 g of a polyamide having repeating units of the following formula and 2 02 g of triethylamine were dissolved in 350 ml of dimethylacetamide.

CF 3 _NH e e Cl g+ 0 NHC 4 _C + C_ CF 3 O O Then 2 09 g of methacrylic acid chloride was gradually dropped into the flask while the temperature of the liquid in the flask was maintained below 5 C and stirred After that stirring was continued for 30 min to allow the polyamide to react with the acid chloride.

Then the reaction liquid was poured into 3 liters of methanol to precipitate the reaction product, and the precipitate was recovered and dried to obtain 8 2 g of a dry product Analysis of the product gave the following results.

H NMR (solvent: D 6-pyridine, internal standard: TMS) = 1 97 ppm (s, -CH 3) = 5 67 ppm (s, -C=CH 2) = 6 45 ppm (s, -C=CH 2) = 7 3 8 7 ppm (m,) Infrared Absorption Spectrum 2950 cm, 2900 cm ( CH 3) 1670 cm, 1660 cm ( Q C=O) 1640 cm ( C=C) -1 1180 cm ( 1) C-F) 1050 cm ( 9) aromatic C=C) In consequence the product was confirmed to be a polymer having repeating units of the following formula.

In the formula, x is the conversion of methacrylic acid chloride, which was 76 % in this example Intrinsic viscosity linh of the polymer was 1 16 d L/g in dimethyl- acetamide at 30 C.

o CH 3 \ / CH 3 II II | 111 (C-C=CH 2)x CF 3 C-C=CH 2 x \ CF 3 O O O For testing, 10 parts by weight of the obtained polyamide was dissolved in 90 parts by weight of cyclo- hexanone The solution was coated on a silicon wafer with a spinner, and drying was made at 1000 C for 3 min to obtain a polymer coating film having a thickness of 1,Am A photomask was placed closely on the coating film, and exposure was made for 10 min with a 450-W high-pressure mercury lamp at a distance of 30 cm Then development was made with a mixed liquid of 80 wt% of isoamyl acetate and 20 wt% of methyl cellosolve As the result a relief pattern was formed in the polymer film.

The relief pattern was heated nearly to 4000 C, but neither dulling of the pattern nor loss of weight was observed.

EXAMPLE 11

The polyamide solution (in cyclohexanone) tested in Example 10 was modified by adding 0 5 part by weight of Michler's ketone to 100 parts by weight of the solution.

Using the modified solution, the coating, exposing and developing process in Example 10 was repeated Also in this case a relief pattern high in heat resistance was formed in the polyamide coating film.

EXAMPLE 12

By the same method as in Example 10, 6 00 g of a polyamide having repeating units of the following formula was reacted with 4 18 g of methacrylic acid chloride in the presence of 4 05 g of triethylamine.

\ CF / After drying the reaction product weighed 7 9 g.

Analysis of the product gave the following results.

H NMR (solvent: D 6-pyridine, internal standard: TMS) = 1 97 ppm (s, -CH 3) = 5 40 ppm (s, -C=CH 2) = 5 67 ppm (s, -C=CH 2) = 6 03 ppm (s, -C=CH 2) = 6 45 ppm (s, -C=CH 2) = 7 3 8 7 ppm (s,) = 10 25 ppm (s, -OH) Infrared Absorption Spectrum 2950 cm-1, 2900 cm 1 () CH 3) 1750 cm 1, 1670 cm, 1660 cm () C=O) 1640 cm-1 () C=C) 1180 cm-1 ( C-F) 1050 cm 1 ( 9 aromatic C=C) In consequence the product was confirmed to be a polymer having repeating units of the following formula.

In the formula, x is the conversion of methacrylic acid chloride, which was 70 % in this example Intrinsic viscosity linh of the obtained polymer was 0 64 d L/g in dimethylacetamide at 30 O C.

09 ? OX O O O CH 2 =-CCF 3 OC-C=CH 2 | H 3 CO CH 3 /x ( CH 2 C=C-r O-O For testing, 15 parts by weight of the obtained polyamide was dissolved in 85 parts by weight of cyclo- hexanone The solution was coated on a silicon wafer with a spinner, and drying was made at 1000 C for 3 min to thereby obtain a polymer coating film having a thick- ness of 3/4 m With a photomask placed on the polymer film, exposure was made for 5 min with the same mercury lamp as in Example 10, and development was made with a mixed liquid of 80 wt% of isoamyl acetate and 20 wt% of methyl cellosolve As the result a relief pattern was formed in the polymer film The relief pattern was subjected to heat treatment at 300 C for 5 min After that the relief pattern was heated nearly to 4000 C, but neither dulling of the pattern nor loss of weight was observed.

EXAMPLE 13

The polymer solution (in cyclohexanone) prepared in Example 12 was modified by adding 1 5 parts by weight of 4 '-methylthio-1,1-dimethyl-1-morpholinoacetophenone to parts by weight of the solution Using the modified solution the coating, exposing and developing process of Example 12 was repeated As the result a relief pattern was formed in the polymer coating film, and by the aforementioned heat treatment the relief pattern became resistant to heat up to about 400 O C.

EXAMPLE 14

By the same method as in Example 10, 4 34 g of a polyamide having repeating units of the following formula was reacted with 5 10 g of methacrylic acid chloride in the presence of 4 94 g of triethylamine.

/ CF 3 NH CF NHC 9 C 3 /11 I o / C O CF 3 O HO I> OH 3 / CF 3 After the reaction, the reaction liquid was poured into 3 liters of n-hexane to precipitate the reaction product After drying the product weighed 5 0 g.

Analysis of the product gave the following results.

1 H NMR (solvent: D 6-dimethylsulfoxid, internal standard: TMS) = 1 96 ppm (s, -CH 3) = 5 50 6 30 ppm (s, -C=CH 2) = 7 20 8 50 ppm (m,) = 9 83 ppm (s, -OH) = 10 46 ppm (s, -NH) Infrared Absorption Spectrum -5 cm 1, 2-1 2950 cm 1, 2900 cm (V CH 3) 1680 cm 1 (U C= 0) 1640 cm-1 ( 1 C=C) 1180 cm-1 (v) C-F) 1540 cm-1 ( O aromatic C=C) In consequence the product was confirmed to be a polymer having repeating units of the following formula.

In the formula, x is the conversion of methacrylic acid chloride, which was 52 % in this example Intrinsic viscosity hinh of the obtained polymer was 0 54 d L/g in dimethylacetamide at 30 O C.

/ H 3 C 30 CH 3 (CH =C-Cx C-C=CH /x CF 3 N CF 3 N-C C C- I 3, I I"= l'-'1 >(c H 2 =H 3 ? ')OC O CF 3 O 3 (CH 2 =C-C O CF 3 O C-C=CH) \ H 3 C O/x \o CH 3 /x For testing, 15 parts by weight of the obtained polyamide was dissolved in 85 parts by weight of cyclo- hexanone, and using this solution the coating, exposing and developing process of Example 12 was repeated Also in this case a relief pattern was formed in the polymer coating film, and the relief pattern became resistant to heat up to about 400 Cby the same heat treatment as in Example 12.

EXAMPLE 15

By the same method as in Example 10, 5 2 g of a polyamic acid (polyimide precursor) having repeating units of the following formula was reacted with 2 09 g of methacrylic acid chloride in the presence of 2 0 g of triethylamine.

/ 0 0 0 -HN -K-o II II II HN + O + NHCljp C r C HO-C C-OH II 0 O As a precipitate from methanol the reaction product amounted to 6 0 g in dry state Analysis of the product gave the following results.

H NMR (solvent: D 6-pyridine, internal standard: TMS) = 1 97 ppm (s, -CH 3) = 5 67 ppm (s, -C=CH 2) = 6 45 ppm (s, -C=CH 2) = 7 3 8 7 ppm (s,) = 11 35 ppm (s, -CO-OH) Infrared Absorption Spectrum -1 2950 cm-1, 2900 cm ( 9 CH 3) 1690 cm-1 ( 9 C=O) 1640 cm-1 ( 9 C=C) 1060 cm-1 ( 9 aromatic C=C) In consequence the product was confirmed to be a polymer having repeating units of the following formula.

In the formula, x is the conversion of methacrylic acid chloride, which was 80 % in this example Intrinsic viscosity Yinh of the obtained polymer was 1 30 d L/g in dimethylacetamide at 30 O C.

/ HC 1 O ' /OCH 1 3 CH 2 =C-Cx C-C=CH 2 x o o O O C CII OH -O C COH II II L 0 0 l For testing 15 parts by weight of the obtained polymer was dissolved in 85 parts by weight of cyclo- hexanone, and using this solution the coating, exposing and developing process in Example 12 was repeated As the result a relief pattern was formed in the polymer coating film, and the relief pattern became resistant to heat up to about 400 C by heat treatment at 300 C for 5 min.

EXAMPLE 16

A solution was prepared by dissolving 15 parts by weight of the polyamide prepared in Example 15 in 85 parts by weight of cyclohexanone and adding 1 5 part by weight of 4 '-methylthio-1,1-dimethyl-1-morpholinoaceto- phenone Using this solution the coating, exposing and developing process in Example 15 was repeated As the result a relief pattern was formed in the polymer coating film, and by the aforementioned heat treatment the relief pattern became resistant to heat up to about 400 C.

EXAMPLE 17

In a 500-ml three-necked flask provided with a dropping funnel, thermometer and stirrer, 10 36 g of 2,2-bisl 4-( 4-aminophenoxy)phenyllhexafluoropropane was dissolved in 100 ml of dimethylacetamide Then a mixed liquid of 4 18 g of methacrylic acid chloride and 100 ml of dimethylacetamide was gradually dropped into the flask while the liquid in the flask was cooled with ice to keep the temperature below 50 C and stirred, and stirring was further continued After that the reaction liquid was poured into 1 liter of ion-exchanged water to obtain a white precipitate Analysis of the recovered and dried precipitate gave the following results.

Infrared Absorption Spectrum -1 3400 cm () NH) -1 2950 cm 1, 2900 cm (J CH 3) 1650 cm-1 ( C=O) 1640 cm-1 ( C=C) Elementary Analysis Calculated (wt%): C 64 22, H 4 31, N 4 28 Found (wt%): C 64 20, H 4 28, N 4 30 In consequence the reaction product was confirmed to be a compound represented by the following formula.

The yield was 97 7 %.

H 3 C O H CF 3 H O CH 1II IF I I H 2 C=C-C-N 2 OON-C-=CH 2 CF 3 In a three-necked flask 6 55 g of the obtained compound was dissolved in 40 ml of dimethylacetamide, and the solution was freezed by using a bath of dry ice and methanol Then 3 07 g of benzophenone-4,4- dicarboxylic acid dichloride was added Thereafter the bath was changed to an ice bath, and gentle stirring was continued for 8 hr After that the reaction liquid was poured into 3 liters of methanol to precipitate the reaction product, which was recovered and dried The dried product amounted to 8 8 g By analysis the product was confirmed to be a polyamide having repeating units of the second formula in Example 10 Intrinsic viscosity Yih of the polyamide was 0 96 d L/g in dimethylacetamide at 300 C.

EXAMPLE 18

In a three-necked flask 6 55 g of the compound prepared by the initial process of Example 17 was dissolved in 40 ml of dimethylacetamide The tempera- ture of the solution was maintained below 100 C, and 3 22 g of 3,3 ',4,4 '-benzophenonetetracarboxylic acid anhydride, which was divided into several portions, was gradually put into the flask Thereafter stirring was continued for 4 hr After that the reaction liquid was poured into 3 liters of methanol to precipitate the reaction product, which was recovered and dried The dried product amounted to 9 6 g Analysis of the product gave the following results.

Infrared Absorption Spectrum 2950 cm 1, 2900 cm ( 9 CH 3) 1690 cm-1 ( C=O) 1640 cm-1 ( 9 C=C) -1 1180 cm-1 (Q C-F) 1060 cm 1 (aromatic C=C) Elementary Analysis Calculated (wt%): C 63 93, H 3 51, N 2 87 Found (wt%): C 63 81, H 3 43, N 2 91 In consequence the reaction product was confirmed to be a polymer having repeating units of the following formula Intrinsic viscosity qinh of the polymer was 1.01 d L/g in dimethylacetamide at 30 O C.

0 CH O CH 3 I 3 / ij 1 1 3 C-C=CH 2 C-C=CH 2 I CF 3 ' I O I,r-,,,II I 11 N-9 O -o-O c- -O_-D N C; C' C CF 3 HO-C C-OH 0 O For testing, 15 parts by weight of this polymer was dissolved in 85 parts by weight of cyclohexanone, and using this solution the coating, exposing and developing process in Example 12 was repeated As the result a relief pattern was formed in the polymer coating film, and by heat treatment at 300 C for 5 min the relief pattern became resistant to heat up to about 400 C.

EXAMPLE 19

The solution tested in Example 18 was modified by adding 1 5 parts by weight of 4 '-methylthio-1,1- dimethyl-l-morpholinoacetophenone to 100 parts by weight of the solution Using the modified solution the pattern forming process in Example 12 was repeated.

Also in this case a relief pattern was formed in the polymer coating film, and by the aforementioned heat treatment the relief pattern became resistant to heat up to about 400 C.

Claims

1 A heat resistant and photosensitive aromatic polyamide resin comprising repeating units repeating units represented by the general formula ( 1):

R 3 R 4 O L l II I} 2 _ 1 N-R -N-C-R -C ( 1) wherein R is an aromatic group, each of R and R is hydrogen atom or an aliphatic or aromatic group which has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray, and R 2 is an aliphatic or aromatic group and, when both R 3 and R 4 in each repeating unit are hydrogen atoms, has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray.

2 A polyamide resin according to Claim 1, wherein R in the general formula ( 1) is T, or > A, where A is -0-, -CO-, -502-, -CH 2-, -C(CH 3)2 C(CF 3)2-, C(CH 3)2 or -0-O D C(CF 3) 27 O_-.

3 A polyamide resin according to Claim 1 or 2, where- in R in the general formula ( 1 l) is r, or j A'l( J, where A' is -0-, -CO-, -CH 2- -C(CH 3)2 or-C(CF 3)2 or C, <CO HOOC COOH 4 A polyamide resin according to Claim 3, wherein 3 4 at least one of R and R in the general formula ( 1) is C=CH 2.

0 CH 3 A polyamide according to Claim 1, wherein both R 3 and R 4 in the general formula ( 1) are hydrogen atoms, and R 1 is an aromatic group having at least one perfluoroalkyl group.

6 A polyamide according to Claim 5, wherein R in the general formula ( 1) is -A' A, where A' is CF 3 CF CF 3 CF 3 -C-,, -0 C or CF 3 CF 3 7 A polyamide according to Claim 5 or 6, wherein R in the general formula ( 1) is -CH=CH-, -CH=CH CH=CH-, t CH=CH or j-t CO-CH=CH 8 A heat resistant and photosensitive aromatic polyamide resin comprising repeating units represented by the general formula ( 2):

3 4 R R 4 00 I 1 2 1 N C-R-C ( 2) CR -COR wherein R 1 is an aromatic group, each of R 3, R 4, R 5 and R 6 is hydrogen atom or an aliphatic or aromatic group which has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray, R 2 3 is an aliphatic or aromatic group and, when all of R 3, R 4, R 5 and R 6 in each repeating unit are hydrogen atoms, has at least one carbon-to-carbon double bond and is dimerizable or polymerizable by an energetic ray, and each of -OR 5 and -OR 6 is at the ortho or peri-position with respect to amido group.

9 A polyamide resin according to Claim 8, wherein R 1 in the general formula ( 2) is, or A, where A is -O-, -C 00-, -SO 2-, -CH 2-, -C(CH 3)2-, -C(CFCH 3 C(CH)2 O or -O C(CF 3)2 - A polyamide resin according to Claim 8 or 9, where- in R 2 in the general formula ( 2) is r, Ior m A', where A' is -0-, -CO-, -CH 2-, -C(CH 3)2 or -C(CF 3)2-' or CO O c.

HOOC COOH 11 A polyamide resin according to Claim 10, wherein each of R, R, R 5 and R in the general formula ( 2) is -C-?=CH 11 C 2 ' O 3 12 A polyamide according to Claim 8 or 9, wherein all of R 3, R 4, R 5 and R 6 in the general formula ( 2) are hydrogen atoms, and R is -CH=CH-, -CH=CH CH=CH-, CH=CH or CO-CH=CH<H.

13. A photosensitive material comprising an aromatic polyamide resin according to Claim 1.

14 A photosensitive material comprising an aromatic polyamide resin according to Claim 8.

15 A method of preparing an aromatic polyamide resin having repeating units represented by the general formula ( 1), I the method comprising reacting a polymer having repeating units represented by the general formula ( 5) with at least one compound which has at least one carbon-to-carbon double bond and is dimerizable or poly- merizable by an energetic ray, said at least one compound being selected from carboxylic acids, carboxylic acid derivatives and epoxides:

H HO O I 1 _ 11 l2 11 N-R -N-C-R -C ( 5) wherein R and R are as defined above with respect to the general formula ( 1).

16 A method according to Claim 15, wherein R 1 in the general formulas ( 1) and ( 5) is,, or -A, A, where A is -0-, -CO-, -SO 2-, -CH 2-, -C(CH 3)2-, -C(CF 3)2-1-O' C(CH 3)2 O or -0 C (CF 3) 2 O_ 17 A method according to Claim 16, wherein R 2 in the general formulas ( 1) and ( 5) is, or A', where A' is -0-, -CO-, -CH 2 -C(CH 3)2 or -C(CF 3)2-, or CO HOOC COOH 18 A method according to Claim 15 or 16, wherein said at least one compound is selected from acrylic acid, chloride, phenyl ester, alkyl esters, hydroxyalkyl esters and methoxyalkyl esters of acrylic acid, methacrylic acid, chloride, phenyl ester, alkyl esters, hydroxyalkyl esters and methoxyalkyl esters of methacrylic acid, cinnamic acid, cinnamic acid chloride, cinnamic acid mthyl ester, glycidyl acrylate, glycidyl methacrylatie, glycidyl cinnamate, hydroxyvinyl ether, chloroethylvinyl ether and maleic anhydride.

19 A method according to any of Claims 15 to 18, wherein said polymer is reacted with said at least one compound in an organic solvent at a temperature ranging from -20 C to the boiling point of said solvent.

A method of preparing an aromatic polyamide resin having repeating units represented by the general formula ( 2), the method comprising reacting a polymer having repeating units represented by the general formula ( 6) with at least one compound which has at least one carbon-to-carbon double bond and is dimerizable or poly- merizable by an energetic ray, said at least one compound being selected from carboxylic acids, carboxylic acid derivatives and epoxides:

/ H HO O \ / ( II II 112 11 N-R N-C-R -C ( 6) HO OH / wherein R 1 and R 2 are as defined above with respect to the general formula ( 2), and each -OH group is at the ortho or peri-position with respect to amido group.

21 A method according to Claim 20, wherein R 1 in the general formulas ( 2) and ( 6) is, or where A is -0-, -CO-, -SO 2-, -CH 2-, -C(CH 3)2-, -C(CF 3)2-' -0-C(CH 3)2 j O or _O 3 -O C(CF 3)20- 22 A method according to Claim 21, wherein R 2 in the general formulas ( 2) and ( 6) is or A', where A' is -0-, -CO-, -CH 2-, -C(CH 3 or-C(CF 3)2or CO HOOC COOH 23 A method according to Claim 20, 21 or 22, wherein said at least one compound is selected from acrylic acid, chloride, phenyl ester, alkyl esters, hydroxyalkyl esters and methoxyalkyl esters of acrylic acid, methacrylic acid, chloride, phenyl ester, alkyl esters, hydroxyalkyl esters and methoxyalkyl esters of methacrylic acid, cinnamic acid, cinnamic acid chloride, cinnamic acid mthyl ester, glycidyl acrylate, glycidyl methacrylatie, glycidyl cinnamate, hydroxyvinyl ether, chloroethylvinyl ether and maleic anhydride.

24 A method according to any of Claims 20 to 24, wherein said polymer is reacted with said at least one compound in an organic solvent at a temperature ranging from -20 C to the boiling point of said solvent.

A method of preparing a heat resistant and photo- sensitive aromatic polyamide resin, substantially as hereinbefore described in any of Examples 1, 4, 5, 10, 12, 14, 15, 17 and 18.

26 A photosensitive material, substantially as herein- before described in any of Examples 1 to 16, 18 and 19.

Published 1989 at The Patent Ofice, State House, 6671 Hgh Eolborn Lndon WC 1 R 4 TP Further copies maybe obtalnedfrom The Patent O Mce.

Sales Branch, St Mary Cray, Orpngton, Kent BP 5 3RD Printed by Multiplex techniques Itd, St Mary Cray, Kent, Con 1187