CA2023668A1 - Radiation-sensitive mixture - Google Patents
Radiation-sensitive mixtureInfo
- Publication number
- CA2023668A1 CA2023668A1 CA002023668A CA2023668A CA2023668A1 CA 2023668 A1 CA2023668 A1 CA 2023668A1 CA 002023668 A CA002023668 A CA 002023668A CA 2023668 A CA2023668 A CA 2023668A CA 2023668 A1 CA2023668 A1 CA 2023668A1
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- Prior art keywords
- radiation
- sensitive mixture
- component
- acid
- compound
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/039—Macromolecular compounds which are photodegradable, e.g. positive electron resists
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G71/00—Macromolecular compounds obtained by reactions forming a ureide or urethane link, otherwise, than from isocyanate radicals in the main chain of the macromolecule
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/2805—Compounds having only one group containing active hydrogen
- C08G18/285—Nitrogen containing compounds
- C08G18/2865—Compounds having only one primary or secondary amino group; Ammonia
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/30—Low-molecular-weight compounds
- C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
- C08G18/3271—Hydroxyamines
- C08G18/3275—Hydroxyamines containing two hydroxy groups
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/027—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/038—Macromolecular compounds which are rendered insoluble or differentially wettable
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- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Medicinal Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Polymerisation Methods In General (AREA)
- Materials For Photolithography (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
- 26 - O.Z. 0050/41050 Abstract of the Disclosure: A radiation-sensitive mixture is composed of (a) a ureido-containing reaction product, (b) at least one organic compound which contains one or more carboxyl groups, (c) at least one ethylenically monounsaturated or polyunsaturated organic compound, (d) optionally, a photoinitiator or photoinitiator system and (e) optionally, further additives and auxiliaries, wherein component (a) is a reaction product of i) at least one di- or polyisocyanate and ii) at least one organic compound having at least one primary or secondary amino group and iii) optionally, one or more compounds having at least one hydroxyl group.
Description
O.Z. 00~0/~1050 Radiation-sensitive mixture The present invention relates to a radiation-sensitive mixture composed of a ureido-containing reac-tion product, a carboxyl-containing compound and an ethylenically unsaturated compound. The present in~ention relates in particular to thosa radiation-sensitive mixtures whos~ solubility in water or aqueous alkali increases on irradiation.
Positive-working light-sensitive compositions, ie. compounds or mixtures of compound~ whose solubility in a given solvent increases on ixradiation, are known per se. The compounds most frequently used in reproduc-tion technology are naphthoquinonediazides and derivat-ives thereof (cf. W. Fra~, Chemie in unserer Zeit, 17 (1983), 10; H.W. Vollmann, Angew. Chem. 92 (1980) 95). On irradiation these compounds eliminate nitrogen and undergo a Wolff rearrangement which converts a hydro-phobic diazoketone unit into a carboxyl group which renders the compound~ mentioned, or mixtures containing these compounds, soluble in aqueou~l alkali.
A further cla~ of compounds which are suitable for preparing positive-working light-sensitive mixtures are aromatic or heteroaromatic nitro compounds. Wherea~
the above-described compounds with a diazoketone struc-tuxe are usually present in light-sensitive mixtures as low molecular weight compounds, light-sensitive nitro compounds can be used not only in the form of low molecu-lar weight compounds (DE-A-22 07 574; US-A-4 181 531) but also as pol~mer~ ormed from monomers ha~ing an o-nitro-carbinol e~ter structure or copolymers of these monomers with other vinyl compounds (cf. DE-A-21 50 691, DE-A-29 22 746 and EP A-19 770). Here too irradiation results in the ormation of a carboxyl group which increases tha solubility of the mixtures in a~ueous alkali.
A similar principle is probably at work with the positive systems which are described for axample in US-A-4 46~ 774 and which contain photoch~mically ~2~:~ $~
Positive-working light-sensitive compositions, ie. compounds or mixtures of compound~ whose solubility in a given solvent increases on ixradiation, are known per se. The compounds most frequently used in reproduc-tion technology are naphthoquinonediazides and derivat-ives thereof (cf. W. Fra~, Chemie in unserer Zeit, 17 (1983), 10; H.W. Vollmann, Angew. Chem. 92 (1980) 95). On irradiation these compounds eliminate nitrogen and undergo a Wolff rearrangement which converts a hydro-phobic diazoketone unit into a carboxyl group which renders the compound~ mentioned, or mixtures containing these compounds, soluble in aqueou~l alkali.
A further cla~ of compounds which are suitable for preparing positive-working light-sensitive mixtures are aromatic or heteroaromatic nitro compounds. Wherea~
the above-described compounds with a diazoketone struc-tuxe are usually present in light-sensitive mixtures as low molecular weight compounds, light-sensitive nitro compounds can be used not only in the form of low molecu-lar weight compounds (DE-A-22 07 574; US-A-4 181 531) but also as pol~mer~ ormed from monomers ha~ing an o-nitro-carbinol e~ter structure or copolymers of these monomers with other vinyl compounds (cf. DE-A-21 50 691, DE-A-29 22 746 and EP A-19 770). Here too irradiation results in the ormation of a carboxyl group which increases tha solubility of the mixtures in a~ueous alkali.
A similar principle is probably at work with the positive systems which are described for axample in US-A-4 46~ 774 and which contain photoch~mically ~2~:~ $~
- 2 - Q.Z. 0050/41050 cleavable benzoin esters in the side chain.
A further instance of solubilization due to carboxyl groups is described for example in EP-A-62 474, EP-A-99 949 or US-A-4 415 652. The mixture contains a water-insoluble binder, a mercaptocarboxylic acid and an initiator system which forms free radicals on irradia-tion. Irradiation causes a free radical graft of the mercaptocarboxylic acid onto the binder, thereby render-ing the latter soluble in aqueous alkali.
In photosensitive mixtures devised according to one of the a~ove-described principles, only at most one carboxyl group is formed or grafted onto the binder per quantum of light absorbed. Usually the quantum yield is still distinctly below 1. For this reason all cases require long exposure times, but the solubility differen-tiation achieved is still poor in most cases. Of the photosensitive systems mentioned, therefore, only those which are based on the Wolff rearrangement of diazo-ketones have become established in the marketplace, and thi~ only in the area of positive offset plates or positive resist~ for the fabrication of integrated circuits. In the case of other products, in particular photoresist films for circuitboard manufaeture, the long exposure times required and the hal-aQueous developers required on account of the lack of solubility dif-ferentiation are unacceptable. The problem of how to dispose of developers will become increasingly important in the future.
A fundamentally different way of increa~ing the solubility of a photosensitive layer by irradiation consists in selecting the composition of the layer in such a way that the average molecular weight of the binder decreases on irradiation. To this end, groups which are cleavable by actinie light are ineorporated in the main chain of a polymer. Examples of such systems are polyoxymethylene polymers which contain aeetal units formed from o-nitrobenzaldehyde or deri~atives of - 3 - O.Z. 0050/41050 o-nitrobenzaldehyde in the main chain. Such polymers and light-sensitive layers prepared therefrom ~re described for example in US-A-3 991 033 and US-A-4 189 611. In the same way it is also possible to incorporate acetals of o-S nitrobenzaldehyde in the main chain of polymers which areessentially polyesters formed from a dicarboxylic acid and a difunctional alcohol (cf~ US-A-4 086 210). Other polymers which on irradiation react by cleaving the main chain and hence reducing the molecular weight are poly-mers which contain hexaarylbisimidazole units in theirmain chain (cf. US-A-4 009 040).
A combination of main chain degradation and grafting with a carboxyl group is the principle exploited in EP-A-57 162 where unsaturated carboxylic acids are present as well as a polymer which cont~ins ben~oin units in the main chain. On irradiation the benzoin units split and reduce the average molecular weight. At the same time the unsaturated carboxylic acids undergo addition to the free radicals ~ormed at the cleavage sites and thus likewise increase the ~olubility in aqueous alkalL.
Again the positive-working photosensitive layers based on the main ~hain degradation o-E a suitable polymer according to one of the principle~l described above are not sufficiently sensitive to light. In addition, a postexposure thermal aftertreatment is necesæary in many cases. For this rea~on none of tha system~ described have become established in practice.
Attempts have therefore been made to utilize the high light-sen3itivity of pho~opolymerizable layers for the production of positive-working layers by forming an inhibitor of the polymerization by imagewise exposure through an original and then polymerizing the non-inhibited areas in a second, not necessarily imagewise exposure step. Exampl~s of compounds proposed for the formation of polymari2ation inhibitors by irradiation are nitroso dimers (cf. DE-~-25 42 lSl) or certain o-ni~ro aromatics (c~. DE-A-27 10 417 and EP-A-103 197). These 2~3~$~
A further instance of solubilization due to carboxyl groups is described for example in EP-A-62 474, EP-A-99 949 or US-A-4 415 652. The mixture contains a water-insoluble binder, a mercaptocarboxylic acid and an initiator system which forms free radicals on irradia-tion. Irradiation causes a free radical graft of the mercaptocarboxylic acid onto the binder, thereby render-ing the latter soluble in aqueous alkali.
In photosensitive mixtures devised according to one of the a~ove-described principles, only at most one carboxyl group is formed or grafted onto the binder per quantum of light absorbed. Usually the quantum yield is still distinctly below 1. For this reason all cases require long exposure times, but the solubility differen-tiation achieved is still poor in most cases. Of the photosensitive systems mentioned, therefore, only those which are based on the Wolff rearrangement of diazo-ketones have become established in the marketplace, and thi~ only in the area of positive offset plates or positive resist~ for the fabrication of integrated circuits. In the case of other products, in particular photoresist films for circuitboard manufaeture, the long exposure times required and the hal-aQueous developers required on account of the lack of solubility dif-ferentiation are unacceptable. The problem of how to dispose of developers will become increasingly important in the future.
A fundamentally different way of increa~ing the solubility of a photosensitive layer by irradiation consists in selecting the composition of the layer in such a way that the average molecular weight of the binder decreases on irradiation. To this end, groups which are cleavable by actinie light are ineorporated in the main chain of a polymer. Examples of such systems are polyoxymethylene polymers which contain aeetal units formed from o-nitrobenzaldehyde or deri~atives of - 3 - O.Z. 0050/41050 o-nitrobenzaldehyde in the main chain. Such polymers and light-sensitive layers prepared therefrom ~re described for example in US-A-3 991 033 and US-A-4 189 611. In the same way it is also possible to incorporate acetals of o-S nitrobenzaldehyde in the main chain of polymers which areessentially polyesters formed from a dicarboxylic acid and a difunctional alcohol (cf~ US-A-4 086 210). Other polymers which on irradiation react by cleaving the main chain and hence reducing the molecular weight are poly-mers which contain hexaarylbisimidazole units in theirmain chain (cf. US-A-4 009 040).
A combination of main chain degradation and grafting with a carboxyl group is the principle exploited in EP-A-57 162 where unsaturated carboxylic acids are present as well as a polymer which cont~ins ben~oin units in the main chain. On irradiation the benzoin units split and reduce the average molecular weight. At the same time the unsaturated carboxylic acids undergo addition to the free radicals ~ormed at the cleavage sites and thus likewise increase the ~olubility in aqueous alkalL.
Again the positive-working photosensitive layers based on the main ~hain degradation o-E a suitable polymer according to one of the principle~l described above are not sufficiently sensitive to light. In addition, a postexposure thermal aftertreatment is necesæary in many cases. For this rea~on none of tha system~ described have become established in practice.
Attempts have therefore been made to utilize the high light-sen3itivity of pho~opolymerizable layers for the production of positive-working layers by forming an inhibitor of the polymerization by imagewise exposure through an original and then polymerizing the non-inhibited areas in a second, not necessarily imagewise exposure step. Exampl~s of compounds proposed for the formation of polymari2ation inhibitors by irradiation are nitroso dimers (cf. DE-~-25 42 lSl) or certain o-ni~ro aromatics (c~. DE-A-27 10 417 and EP-A-103 197). These 2~3~$~
- 4 - O.Z. 0050/41050 systems all require an addi~ional exposure step, so that if anything the total process tLme is increased compared with other positiv~ systems.
The hitherto most successful attempt at increas-ing the light sensitivity of positive-wor~ing light-sensitive layers has become known as chemical enhance-ment. Here irradiation leads to the formation of a catalyst which in a second, thermal step, catalyzes a reaction which ultimately leads to an increase in the solubility of the photosensitive layer. The catalyst is usually a strong acid which is formed photochemically, for example, from an organic halogen compound, in par-ticular a halogen containing triazine compound (cf. for example DE-A-23 06 248), an aromatic nitro compound (cf.
for example EP-A-78 981), a diazonium salt or an aromatic iodonium or sulfonium salt (cf. for example DE-A-36 30 677 and US-A-4 491 628~. The acid formed is used for splitting acid~labile ~onds in the second, thermal step o the process. Depending on the acid-labile compound used, thi~ splitt.ing can lead eithar to the formation of a hydrophilic group from a hydrophobic group (cf. ~or example DE-A-36 20 677 and US-A-4 491 62~) or to a decrease in the molecular weight. Examples o~ acid-labile groups suitable for the last case are acetal (cf.
DE-A-23 06 248, EP-A-78 981, EP-A-82 463 and US-A-3 ~79 778), orthocarboxylic-ester (cf. EP-A 78 981 and EP A-82 463), enol ether (cf. EP-A-6 627 and EP-A-82 463), ~ilyl ether (cf. DE-A-35 44 165 and EP-A-130 599) or silyl ester group~ (cf. EP-A-130 599).
Although these mixtures make it possible to achieve light sensitivities which in the ba~t ca~es correspond to those of negative-working layer~, products which are construc-ted according to the principle of chemical enhancement have become importan~ only within the area of resi~ts for 3 fabrica~ion of in~egrated circuit~. In o~her fields, the . additional thermal step requirQd is not acceptable.
A further type of a positive-working 2~2~
The hitherto most successful attempt at increas-ing the light sensitivity of positive-wor~ing light-sensitive layers has become known as chemical enhance-ment. Here irradiation leads to the formation of a catalyst which in a second, thermal step, catalyzes a reaction which ultimately leads to an increase in the solubility of the photosensitive layer. The catalyst is usually a strong acid which is formed photochemically, for example, from an organic halogen compound, in par-ticular a halogen containing triazine compound (cf. for example DE-A-23 06 248), an aromatic nitro compound (cf.
for example EP-A-78 981), a diazonium salt or an aromatic iodonium or sulfonium salt (cf. for example DE-A-36 30 677 and US-A-4 491 628~. The acid formed is used for splitting acid~labile ~onds in the second, thermal step o the process. Depending on the acid-labile compound used, thi~ splitt.ing can lead eithar to the formation of a hydrophilic group from a hydrophobic group (cf. ~or example DE-A-36 20 677 and US-A-4 491 62~) or to a decrease in the molecular weight. Examples o~ acid-labile groups suitable for the last case are acetal (cf.
DE-A-23 06 248, EP-A-78 981, EP-A-82 463 and US-A-3 ~79 778), orthocarboxylic-ester (cf. EP-A 78 981 and EP A-82 463), enol ether (cf. EP-A-6 627 and EP-A-82 463), ~ilyl ether (cf. DE-A-35 44 165 and EP-A-130 599) or silyl ester group~ (cf. EP-A-130 599).
Although these mixtures make it possible to achieve light sensitivities which in the ba~t ca~es correspond to those of negative-working layer~, products which are construc-ted according to the principle of chemical enhancement have become importan~ only within the area of resi~ts for 3 fabrica~ion of in~egrated circuit~. In o~her fields, the . additional thermal step requirQd is not acceptable.
A further type of a positive-working 2~2~
- 5 - O.Z. 0050/41050 light-sensitive mixture i8 described in EP-A-106 156.
This mixture consists of a polycondensate ha~ing certain groups in the main chain and unsaturated groups at the end of the chain in combination with a photoinitiator.
Groups mentioned for forming the main chain are aromatic hydrocarbon, diaryl ether, diaryl sulfide, diaryl sulfone, diarylamine, diaryl ketone and diaryl diketone groups. End groups are alkenyl groups or unsaturated carboxylic acid groups. The cause for the increase in the solubility on irradiation is suspected to be a chain degradation process induced by fr~e radicals. Despite the very high initiator content of typically 25% by weight, only moderate light sensitivities are achieved.
The examples ~how that in most ar~a~ there i~
still a demand for new positive-working light-sensitive mixture~ which combine high light-sensitivity and ease of handling, ie. in particular the ab~ence of additional operations.
It is an ob~ect o~ the present invention to develop a positive-working light-sensiti~e mixture having the properties mentioned and to devise it~ underlying reaction product.
We have ~ound, surprisingly, that this ob~ect is achi~vad in tha~ the solubility of mixtures of (a) certain uraido-containing reaction products, (b) com-pounds which contain one or more carbo~yl groups, and (c) ethylenically unsaturated compound~ increases on irradia-tion in the presence of compounds from which free radi-cals are formed on irradiation.
The pre3ent invention accordingly provides a radiation-sensitive mixture formed from (a) a ureido-containing reac~ion product, ~b) at least one organic compound which contain3 one or more carboxyl group3, (c) at least one ethylenically monounsaturated or polyunsaturated organic compound, (d~ an optional photoinitiator or photoinitiator ~`2~ 8 - 6 - O.Z. 0050/41050 system with or without (e) further additives and auxiliaries, wherein component (a) is a reaction product of i)- at least one di- or polyisocyanate and ii) at least one organic compound having at least one primary or secondary amino group and iii) one or more optional compounds having at least one hydroxyl group, the number of NCO groups in component i) being equal to or less than the num~er of groups in ii) and iii) which are reactive therewith.
The present invention provides in particular those radiation-sensitive mixtures whose solubility in water or aqueous alkali increases on irradiation or exposure to light.
In particular embodiments of the present inven-tion, the reaction product (a) to be used according to the present invention is prepared u~ing as component i) a diisocyanate, as componant ii) one or more primary and/or secondary amines of the general formula R'HN-R-XH tI) where is the divalent radical of a su~stituted or unsub-stituted alkane, arene, ether, polyether, amine, poly-amine, ester, polyester, amide or polyamide,R' is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl, a derivative thereof or the monovalent radical H~O~(CH2)n-CHR"~m ~here n is from 1 to 3, m is from 1 to 10 and R" is H or Cl-C4-alkyl, or an isomer thereof, X is O, S or NR"', R"' is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl or a derivativa thereof, and/or at least one amino compound o the general formula ~ 3~ $
This mixture consists of a polycondensate ha~ing certain groups in the main chain and unsaturated groups at the end of the chain in combination with a photoinitiator.
Groups mentioned for forming the main chain are aromatic hydrocarbon, diaryl ether, diaryl sulfide, diaryl sulfone, diarylamine, diaryl ketone and diaryl diketone groups. End groups are alkenyl groups or unsaturated carboxylic acid groups. The cause for the increase in the solubility on irradiation is suspected to be a chain degradation process induced by fr~e radicals. Despite the very high initiator content of typically 25% by weight, only moderate light sensitivities are achieved.
The examples ~how that in most ar~a~ there i~
still a demand for new positive-working light-sensitive mixture~ which combine high light-sensitivity and ease of handling, ie. in particular the ab~ence of additional operations.
It is an ob~ect o~ the present invention to develop a positive-working light-sensiti~e mixture having the properties mentioned and to devise it~ underlying reaction product.
We have ~ound, surprisingly, that this ob~ect is achi~vad in tha~ the solubility of mixtures of (a) certain uraido-containing reaction products, (b) com-pounds which contain one or more carbo~yl groups, and (c) ethylenically unsaturated compound~ increases on irradia-tion in the presence of compounds from which free radi-cals are formed on irradiation.
The pre3ent invention accordingly provides a radiation-sensitive mixture formed from (a) a ureido-containing reac~ion product, ~b) at least one organic compound which contain3 one or more carboxyl group3, (c) at least one ethylenically monounsaturated or polyunsaturated organic compound, (d~ an optional photoinitiator or photoinitiator ~`2~ 8 - 6 - O.Z. 0050/41050 system with or without (e) further additives and auxiliaries, wherein component (a) is a reaction product of i)- at least one di- or polyisocyanate and ii) at least one organic compound having at least one primary or secondary amino group and iii) one or more optional compounds having at least one hydroxyl group, the number of NCO groups in component i) being equal to or less than the num~er of groups in ii) and iii) which are reactive therewith.
The present invention provides in particular those radiation-sensitive mixtures whose solubility in water or aqueous alkali increases on irradiation or exposure to light.
In particular embodiments of the present inven-tion, the reaction product (a) to be used according to the present invention is prepared u~ing as component i) a diisocyanate, as componant ii) one or more primary and/or secondary amines of the general formula R'HN-R-XH tI) where is the divalent radical of a su~stituted or unsub-stituted alkane, arene, ether, polyether, amine, poly-amine, ester, polyester, amide or polyamide,R' is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl, a derivative thereof or the monovalent radical H~O~(CH2)n-CHR"~m ~here n is from 1 to 3, m is from 1 to 10 and R" is H or Cl-C4-alkyl, or an isomer thereof, X is O, S or NR"', R"' is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl or a derivativa thereof, and/or at least one amino compound o the general formula ~ 3~ $
- 7 ~ O.Z. 0050/41050 ~Rl~
\R2/
where Rl and R2 are identical or different and each is the divalent radical of a substituted or unsubstituted alkane, arene, ether, polyether, amine, polyamine, ester, polyester, amide or polyamide, R3 is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl or a derivative thereof, or a combination of at least one of the~e amines and at least one further primary or secondary amine different therefrom and as component iii) an aliphatic monoalcohol.
A suitable component tb) is in particular a c~rboxyl-containing compound having an average molecular weight F~
of above 10,000 and an acid number of from 50 to 300 mg of KOH/g. Particular preference i~ given to copolymers formed from an acid monomer and at least one hydrophobic monomer, the acid monomer being prelferably acrylic acid, methacrylic acid, crotonic acid or itaconic acid and the hydrophobic monomex being preferably a styrene, an acrylate or a methacrylate.
A suitable ethylenically monounsaturated or polyunsaturated compound (c) is an ~ ethylenically unsaturated carbonyl compound, pre~erably an acrylate or methacrylate.
Component~ ~b) and (c) may al~o be identical.
Preferred components (d) are benzophanone and derivatives thereof, hexaarylbisimidazole derivatives, N-alkoxypyridinium salts and mixture3 thexeof.
The ureido-containing reaction product ~a) o the radiation-sen3itive mixture according to the present invention is prepared by reacting the isocyanate com-3S ponent i~ with the amine component ii) and optionallywith the hydro~yl component iii) by using the groups which ars reactive towards isocyanate in an equivalent - 8 - O.Z. OOSO/~lOSO
amount or in excess, pre~erably in a rakio of from 1:1 to 4:1. Components i3 to iii) can be reacted simultaneously or in stages in any desired order.
~ This reaction can be carried out wi~hout a solvent or alternatively in an inert sol~ent, eg. ace-tone, tetrahydrofuran, dioxane, dichloromethane, toluene, methyl ethyl ketone or ethyl acetate. Other suitable solvents are the ethylenically monounsaturated or polyun-saturated compounds, if they are liquid.
The temperature for the reaction of the isocyan-ate groups is in general within the range from O to 100C, preferably from 20 to 70~C.
To speed up the reaction it is possible to use catalysts as described for example in Houben-Weyl, Methoden der organischen Chemie, volume XIV/2, p. 60f, Georg Thieme-Verlag, Stuttgart (1963) and Ullmann, Encyclopadie der technischen Chemie, volume 19, p. 306 (1981). Preference is given to tin-containing compounds such as dibutyltin dilaurate, tin(II) octoate and di-butyltin dimethoxide.
In general, the catalyst i~ used in an amount of from 0.001 to 2.5% by weight, pre~erably from O.OOS to 1.5~ by weight, based on the total amount of the reac-tants.
There now follow detailed observations concerning the formative components ~or preparing the reaction produc~ (a) and their use in the radiation-sensitive mixtures according to the present invention with com-ponents (b) to (d).
A suitable compound for use as a di- or polyiso-cyanate i) for the reaction of components i) to iii) is any compound which contains at least ~wo isocyanate groups capable of reaction with alcohols or primary or secondary amines. Particular preference is given to diisocyanatodiphenylmethane, diisocyanatotoluene (= toluylen~ diisocyanate), hexamethylene diisocyanato and isophorone diisocyanate, and also to oligomers ~2~ ~ $`
~ g - O.Z. 0050/41050 thereof of the isocyanurate and biuret type.
Suitable amino compounds ii) are all prLmary and secondary amines which are reactive toward isocyanate groups. Examples are n-butylamine, n-pentylamine, n-hexylamine, dodecylamine, benzylamine, ethylhexylamine,dibutylamine, ethylisopropylamine, l-methoxy-2-aminopro-pane, dibenzylamine, 1,5-dimethylhexylamine, dipentyl-amine, dihexylamine, cyclopropylamine, cyclopentylamine, methylbenzylamine and mixtures ther~of.
Of particular suitability are amines of the general formula R'HN-R-XH (I) and/or / R' \ (II) where, in the general formula (I) R'HN-R-XH (I) R is the divalen~ radical of a substitu~ed or unsubstituted alkane, for example of from ~ to 10 carbon atoms, such as -(CH2)p- where p is from 2 to 10~ -CH2-C(CH3)2-CH2- or -CH(CH3)-C~I2-, of an arene, for example phenyl~ne, of a substituted arene, for example -(CH2)r~-C6H3(OX)- where r is from 1 to 6, preferably 2, of an ether, for example -(CH2-CHRIV-O-)q-CH2-CHRIv- where q is from 1 to 5, and RIV i9 H or alkyl of from 1 to 4 carbon atoms, of an amine, for example of from 2 to 20 carbon atoms, eg. -(CH2)3-N(CH3)-(CH2)3-, f a polyamine, for example -(CH2-CH2-NH)o- where o is from 2 to 5, of an ester, for example of from ~ to 20 carbon atoms, eg. -(CH2)2-COO-(CH2),- where s is from 2 to 6, -CH2-COO-CH2-CH(C~3)-, or of an amide, for example of from 4 to 20 carbon atoms, e g . - ( C H 2 ) 2 - C O N H - C H 2 ~ o r -(CH2)2-CoN~-(c}~2)5-NHoc-(cH2)2-;
R' is hydrogen, alkyl, for example of from 1 to 30, ~ ~ 2 ~
- 10 - O.Z. 0050/41050 preferably from 1 to 10, carbon atoms, eg.
methyl, ethyl, propyl, butyl and isomers thereof, cyclohexyl, aryl, for example of from 6 to 18 - carbon atoms, preferably phenyl, naphthyl, aralkyl, for example of from 7 to 20 carbon atoms, eg. benzyl, 1-phenylethyl, l-methyl-3-phenylpropyl, hydroxyalkyl, for example of from 2 to 10 carbon atoms, eg. hydroxyethyl, hydroxy-propyl, hydroxybutyl, aminoalkyl, for example of from 2 to 10 carbon atoms, eg. aminoethyl, aminopropyl, dimethylaminobutyl, dimethyl-aminoneopentyl, mercaptoalkyl, for example of from 2 to 10 carbon atoms, eg. mercaptoethyl, or derivatives of these groups - derivatives being in the present case alkyl-, aryl-, halogen~, carboxyl-, nitro-, nitrile-, sulfoxyl--, amino-, alkoxy- or aryloxy-substituted gro~ps of the aforamentioned kind - or the monovalent r~dical K~O-(CH2)n-CHR"~m where n :is from l to 3, m is from 1 to 10 and R" is H or Cl-C4-alkyl, or isomers thereof as obtainahle by Yimple addition or polyaddit~on o~ cyclic ethers, eg. ethylene oxide, propylene oxide or ~etrahydro~uran, for ex~npLe hydroxyethyloxyethyl;
X is O, S or NR"', where R"' is hydrogen, al~yl, for example of from 1 to lO carbon atoms, eg.
methyl or ethyl, aryl, ~or example phenyl or naphthyl, aralkyl, for example benzyl or phenyl-ethyl, hydroxyalkyl, ~minoalkyl or mercaptoalkyl, with alkyl groups which may each contai~ from 1 to 10 carbon atoms, or derivatives o~ these groups of the type mentioned under R'.
Examples of compounds of the general formula R'HN-R-XH are ethylenediamine, butanediamine, 3S neopentanediamine, polyoxypropylenediamines, polyoxyethylenediamines, N-ethylethylenediamine, diethylenetriami.ne, monoisopropanolamine.
2 ~ 2 3 ~ ~ ~
~ O.Z. 0050/41050 Particular preference is gi~en to ethanolamine, diethanolamine, diisopropanolamine, neopentanol-amine, ethylisopropanolamine, ltylethanolamine ~ and 2-mercaptoethylamine.
In the general formula (II) / Rl~
HN ~ R3 (II) R1 and R2 are identical or different and each is in particular the divalent radical of a sub-stituted or unsubstituted alkane, for example of from 2 to 4 carbon atoms, eg. -tCH2)t- where t is from 1 to 4, of an arene, for example o-phenylene, or an ether, for example of from 2 to 4 carbon atoms, eg. -CH2-O-CH2-;
R3 is a hydrogen, alkyl, aryl, aralkyl, hydroxy-alkyl, aminoalkyl, mexcaptoalkyl or a derivative thereof of the type mentioned under R'. Praferred compounds of the general formula (II) R1 \
HN NR3 ~II) \ R2/
are piperazine and 1-(2-hydroxyethyl)piperazine.
Similarly, it i al30 pos~ible to use mixtures of the amino compounds mentioned under ii), whose reaction with isocyanate may be effected simultaneously or in stages.in any desired order. Preferred combinations consis~ of amines o~ the general for~ulae (I) and/or (II) and primary or socondary amines. Particularly pxaferred combination~ are hydroxyalkylamino compounds, eg. diiso-propanolamine, diethanolamine or ethanolamine, with primary or secondary aliphatic amines, eg. butylamine or dibutylamine.
Suitable compounds iii) for inclusion as having at least one hydro~yl function are all mono- and multi-~unctional alcohols which are reactive toward isocyanate groups. Examples are mono-, di- and trialcohol~ of ~rom ~2~
- 12 - O.Z. 0050/41050 1 to 20 carbon atoms, such as methanol, ethanol, n-propanol, isopropanol, butanol, 1-methoxybutanol, ethy-lene glycol, propylene glycol, butanediol, hexanediol, cyclohexanedimethanol, glycerol, trimethylolpropane, etc.
Preference is given to aliphatic alcohols of from 1 to 6 carbon atoms.
(b) Suitable organic compounds for inclusion as having one or more carboxyl groups are low molecul~r weight carboxylic acids, for example monocarboxylic or dicar-boxylic acids containing from 1 to 20 carbon atoms, eg.adipic acid, phthalic acid, terephthalic acid, malonic acid, succinic acid or maleic acid. A particularly suitable component (b) is a carboxyl-containing compound which, owing to its composition and its molecular weight, has good film forming properties. Preference i5 given to polymers having an av~rage molecular weight ~ of above 10,000, preferably of from 15,000 to 300,000, and an acid number which is within the range from 50 to 300 mg of KOH/g. Particular preference i~ given to copolymers formed from an acid monomer, eg. ac:rylic acid, methacry-lic acid, crotonic acid or itaconic acid, and one or more hydrophobic comonomers, eg. styrene, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate or methyl meth-acrylate. Of particular ~ui~:ability are also styrene/maleic anhydride copolymers which have been partially ecterified with lower alcohol~. The composition of these copolymers is chosen in such a way that they are compatible with component ta).
The mixing ratio of component ~b) to component (a) is chosen in ~uch a way that the radiation-sensitive mixtures according to the present invention are insoluble in the developer used but become ~oluble therein on irradia~ion. The concentration range in which this is achieved naturally depen~s strongly on the compesition of component (b). In general, a favorable concentration range for (b) is from S to 40% by weight, particularly preferably from 10 to 30~ by weight, based on the total ~%3~
- 13 - O.Z. OOS0/4105 weight of the radiation-sensitive mixture.
tc) Suitable ethylenically monounsaturated or poly-unsaturated compounds are low molecular weight or oligo-meric compounds having at least one ethylenically un-saturated double bond. The compounds are selected foxcompatibility with the other constituents of the radiation-sensitive mixture according to the present invention. P~eference i5 given to ~,~-unsaturated car-bonyl compounds. Particular pre~erence is given to acrylates and methacrylates, for example alkyl (meth)-acrylates, alkylpolyethylene or arylpolyethylene glycol (meth)acrylates at from 2 to 10 propylene glycol units, alkylpolypropylene or arylpolypropylene glycol (meth)-acrylates having from 2 to 10 propylene glycol units, polyethylene glycol di(meth)acrylates having ~rom 2 to 10 ethylene glycol units, polypropylene glycol di(meth)-acrylates having from 2 to 10 propylene glycol unit~ or reaction products of bisphenol A, epichlorohydrin and (meth)acrylic acid. The ethylenically unsaturated com-pounds (c) are preferably added to the radiation-sensi-tive mixture in a concentration o from 1 to 40~ by weight, par~icularly pro~erably ~rom 3 to 25% by weight, based on the total weight of the radiation-~ensitive mixture. A high concentration, ie. more than 15~ by weigh~, is chosen in particular when, following a first exposure step and the removal of the irradiated material in a d~veloper, a crosslinking is to be brought about in a second, longer exposure ~tep in order that in this way the mechanical stability, for example printing plates, be improved.
It is also possible, furthermore, to combine components (~) and (c) in one compound, ie. to use a carboxyl-containing ethylenically unsaturated compound.
Examples of such compounds are fumaric acid, maleic acid, (meth)acrylic acid and reaction products of hydroxyl-containing acrylates, for example ~-hydroxyalkyl acry-late~, as obtained by reacting epoxy compounds with 2~2~$~
- I4 - O.z. OOSa/41050 acrylic acid or incomplete esterification of di- and polyalcohols with acrylic acid, or hydroxy-functional urethane acrylates obtained by reacting an ~xcess of di-or~polyalcohols with isocyanate compounds, with acid anhydrides, eg. maleic or phthalic anhydride. Preference is also given here to using polymeric compounds which have good film forming properties owing to their mole-cular weight. Such polymeric compounds which contain not only carboxyl groups but also ethylenically unsaturated groups can be obtained for example from the copolymers of ~tyrene, (meth)acrylate and (meth)acrylic acid mentioned above as component (b) by reaction with glycidyl acrylate or methacrylate. This re~ction is preferably carried ou~
in such a way that 5 to 40% of the free carboxyl groups of the copolymer are converted.
Another possible way of preparing polymers having carboxyl groups and ethylenically unsaturatecl groups comprises including hydroxyalkyl (meth)acrylate units in the polymer in addition to the abovlementioned comonomers and to react the hydroxyl groups in a second step with anhydrides of unsaturated carboxylic acids, eg. maleic anhydride or methacrylic anhydride. The skilled worker will o~ course be ~amiliar wi~h still further methods for preparing ~he polymer~ mentioned. The compounds men-tioned, which contain not only carboxyl groups but alsoethylenically unsaturated groups, are preferably used in a concentration of from 5 to 60~ by weight, particularly preferably from 10 to 40% by weight, based on the total weight o~ the radia~ion-sensitive mixture.
(d) The photoinitiators which may be included in the radiation-sensitive mixture according to the present invention are the photoinitiators and photoinitiator systems which are customary and kn~wn per se for light-sensitive photopolymerizable recording materials. Speci-fic examples are: benzoin, benzoin ethers, in particularbenzoin alkyl ethers, substituted benzoins, alkyl ethers of substituted benzoins, eg. ~-methyl-benzoLn alkyl ~3~
- 15 - O.Z. 0050/41050 ethers, or ~-hydroxymethylbenzoin alkyl ethers; benzils, benzil ketals, in particular benzil dimethyl ketal, benzil methyl ethyl ketal or benzil methyl benzyl ketal;
the acylphosphine oxide compounds known for use as effective photoinitiators, eg. 2,4,6-trimethylbenzoyl-diarylphosphine oxide; benzophenone, derivatives of benzophenone,4,4'~dime~hylaminobenzophenone,derivatives of Michler's ketone; anthraquinone and substituted anthraquinones; aryl-substituted imidazoles or derivatives thereof, eg. 2,4,5-triarylimidazole dimers;
thioxanthone derivatives, the active photoinitiator acridine or phenacine derivatives and N-alkoxypyridinium salts and derivatives thereof. Suitable pho~oini~iators also include diazonium salts, eg. p-phenylamino-benzenediazonium hexafluorophosphatel iodonium salts, eg.diphenyliodonium tetrafluoroborate, or sulfonium salts, eg. triphenylsulfonium hexafluoroarsenate. Examples of initiator systems are combinations of the aforementioned initiators with sensitizing a~sista~nts or activators, in particular tertiary amines. Typic:al examples of such initiator systems are combinations of benzophenone or benzophenone derivatlves with tertiary amine~, such as triethanolamine or Michler's ketone; or mixtures of 2,4,5-triarylimidazole dimers and Michler's ketone or the leuco bases of triph~nylmethane dyes. The choice of suitable photoinitiator~ or photoinitiator systems i5 known to the skilled worker. Particularly preferred photoinitiators are Michler's ketone, ben20phenone, hexaarylbisimidazole derivatives and N-alkoxypyridinium salts. It is also very advantageouR to use mixtures of said photoinitiators. The photoinitiators or photoiniti-ator systems are in general present in the light-sensitive recording layer in amounts of from 0.1 to lO~
by weight, based on the radiation-sensitive mixture.
(e) Suitable additives andJor auxiliaries (e) or possible inclusion in the radiation-sensitive mixture according to the present invention include for example .. . ,.. ~ . ~. ...
- 16 - O.Z. 0050/41050 dyes and/or pigments, photochromic compounds and systems, sensitometric regulators, plasticizers, flow control agents, delusterants, lubricants, basic components and the like. Examples of dyes and/or piqments, which may serve not only as contrast agents but also to reinforce the layer, include inter alia srilliant Green ~C. I . 42 040 ), Victoria Pure Blue FGA, Victoria Pure Blue 80 (C.I.
42 s9s)r Victoria Blue B (C.I. 44 045), Rhodamine 6 G
(C.I. 45 160), triphenylmethane dyes, naphthalimide dyes and 3'-phenyl-7-dimethylamino-2,2'-spirodi(2H-l-benzopyran). Photochromic or color change systems which on irradiation with actinic light undergo a reversible or irreversible color change without thereb~ interfering with the photopolymerization process are for example leuco dyes together with suitable activators. Examples of leuco dyes are the leuco bases of triphenylmethane dyes, such as crystal violet leuco base and malachite green leuco base, leuco Basic Blue, leuco pararosaniline, leuco Patent Blue A or V; it is also possible to use Rhodamine B base. Suitable acti~ators for these photochromic compound~ include inter alia organic haloqen compounds which eliminate the halogen radicals on irxadiation with actinic light or hexaarylbisimida2:01es. Suitable color change systems are also described in DE-A-38 24 551.
Particularly suitable color change systems are those where the color intensity decreases on irradiation, for example Sudan dyes, polymethine dye~ or azo dyes combined with suitable photoinitiators. Su.itable sensitometric regulators include compounds such as 9-nitroanthracene, lO,lO'-bisanthxone, phenazinium, phenoxazinium, acridinium or phenothiazinium dyes, in particular com-bined with mild reducing agents, l,3-dinitrobenzane3 and the like. Suitable plasticizers are the known and cus-tomary low or high molecular weight esters, such as phthalates or adipates J toluenesulonamide or tricresyl phosphatQ. Suitable basic components are additions of amines, in particular tertiary amines, eg. triethylamine - 17 - O.Z. 0050/41050 or triethanolamine, or alkali metal or alkaline earth metal hydroxides and carbunates. The additives and/or assistants are present in the radiation-sensitive mixture in~the effective amounts known and customary for these S substances. However, ~heir amount should in general not exceed 30% by weight, preferably 20~ by weight, based on the radiation-sensitive mixture.
A film or coating can be prepared by dissolving the above-described radiation-sensitive mixture in a solvent and then applying the resulting mixture to a permanent or temporary support by casting, with or without a doctor blade, spin coating, roller coating or some other technique.
Suitable solvents are for example aromatic hydrocarbons, low molecular weight ketones, alcohols, ethers, esters and chlorocarbons.
A suitable support for the radiation-sensitive coatings according to the present invention i4 virtually any material which is customary in printing and in the fabrication of circuit boards for the electronics in-dustry. However, an impor~ant condition i~ that the support be inert, ie. that it should not react with the radiation-sensitive mixture used for preparing the coating.
Suitable support materials are for example steel, aluminum alloys, mechanically, chemically or electro-chemic~lly roughened aluminum, silicon, polyesters and other plastics. The layer thicknass here may vary within wide limits. If the radiation-sensitive mixture Ls used for examp , as a letterpress or intaglio printing plate, it will typically be within the ranga from 50 to 500 ~m, if used as a photoresist for the ~abrication of printed circuits within the range rom ~0 to lO0 ~m and i~ used as a photoresist for structuring semicondu~tor materials within the range from 0.3 to 5 ~m. If the radiation-sensitive mixture according to the present invention is used as an offset printing plate, the coating will be .~, ~
g - 18 - O.Z. 0050~41050 prepared in such a way as to prod~ce dry layer weights of from 0.5 to 5 g/sqm.
The radiation-sensitive mixtures according to the present invention are advantageous for producing printing plates or resist patterns in a conventional manner. To this end the light-sensitive recording layer - in the case of photoresist films and laminating materials after lamination to the substrate to be protected - is sub-jected to imagewise exposure with ac~inic light, suitable sources of which are the customary ones, such as W
fluorescent tubes, mercury high, medium or low pressure lamps, superactinic fluorescent tubes, pulsed xenon lamps or even W lasers~ argon lasers and the like. The wave-length emitted by the light sources should in general be within the range from 230 to 450 nm, preferably within the range from 300 to 420 nm, and be adapted in par-ticular to the characteristic absorption of the photo-initiator present in the photopolymerizable recording layer.
Following imagewise exposure, the printing plate or resist pattern is developed by washing out the irra-diated areas of the recording layer with water or pre~er-ably an aqueous alkali. ~he proce~is of development can take the form of washing, spraying, rubbing, brushing etc. The recording elements according to the present invention here show a wide exposure latitude and a very low ovexwa~h sen~itivity. Suitable developers are aqueous alkalis which to set the best pH, in general pH 8-14, preferably a pH within the range from 9 to 13, contain alkaline substance~, for example borax, disodium hyd-rogenphosphate, sodium carbonate, alkali metal hydroxides or organic bases, such as di- or triethanolamine, dis-solved in water. The aqueouq alkali developers may also contain buffer salts, for example water-soluble alkali metal phosphates, silicate~, borates, acetates or benzo-ates. Further suitable constituents of developer~ ars wetting agents, preferably anionic wetting agents, and $ ~ ~
- 19 - O.Z. 0050/41050 possibly water-soluble polymers, for example sodium carboxymethylcellulose, polyvinyl alcohol, polysodium acrylate and the like. Although the recording elements according to the present invention are in general washe~
j out with water or aqueous alkali, it is of course pos-sible in principle, although not strictly necessary, that the developer should _lso contain a small amount of water-soluble organic solvent, for exampl~ an aliphatic alcohol, acetone or tetrahydrofuran.
The radiation-sensitive mixtures according to the present invention can be structured for example by high-energy radiation such as electron bea~s or X-rays, when they show their very high sensitivity to radiation. If used in this way it is generally possible to dispense with the addition of a separate initiator system. If, by contrast, the mixtures according to the present invention are to be structured by visible or W light, as is customary for production of printing plates and photo-resists, it is advisable to add suitable photoinitiators whose spec~ral sensitivity matches the emi~ted spectrum of the light source used. The~e mixtures likewise show very high ligh~ sensitivity or positive-working systems, which corresponds to the light sensitivity of commercial negative systems of 9im~ lar thickness. This high light sensitivity is obtained without any need for additional operations, for example the thermal aftertreatment which is necessary with many othar positive ~y~tems. Similarly, the developers used correspond to those used for negative-working layers, so that the recording layers according to the presen~ invention are complately compat-ible with conventional system~. The radiation-sensitive recording layers according to the present invention are highly suitable for multiple exposures. This makes it possible in many applications to save process steps.
Multiple exposures are not possible with all photopoly-merizable systems, including many posi~ive systems, for fundamental reasons. The radiation-sensitive mixtures ~ 20 - O.Z. 0050/41050 according to ~he present invention also ha~e the inter~
esting property of acting as positive systems for short exposure times but as crosslinkable systems for long exposure times. This effect occurs in particular when the radiation-sensitive mixture con~ains the ethylenically monounsaturated or polyunsaturated compounds c~ in an amount of > 15~ by weight. This property can be utilized after a first, imagewise exposure step with a short exposure ~ime and after removal of the irradiated areas in a developer for initiating a crosslinking reaction in a second, not nacessarily imagewise exposure step using a distinctly longer exposure tLme. In this way it is possible to improve the mechanical properties, for example of printing plates.
The invention is illustrated in more detail by the Examples which follow.
In the method of preparation and in the Examples, the parts ancl percentages are by weight, unless otherwise stated.
Preparation of the reaction products (a) to be used according to the present invention"
Method of preparation 154.8 g of di-n-butylamine (1.2 mol) are added dropwise to a mixture of 266.4 g of isophorone diisocyan-ate (1.2 mol) and 251 g of methyl ethyl ketone at 16-18C
with ice cooling for 30 minutes. Following a reaction time o~ 30 minutes at a maximum temperature of 46C, 150.4 g of diisopropanolamine (1.13 mol) are added dropwise at 46C in the course of 20 minutes, during which the temperature rises to 50C. The reaction ends ater 4 hours at 50C. The 67.8~ strength solution has a viscosity of 500 mPa.Y (measured at 23C with a cone/
plata viscometar).
EXAMPL~ 1 ~5 7 g of tha reaction product prepared in accor-dance with the above method of preparation, 2.5 g of a copolymer of styrene (25~), methyl methacr~late (35~), - 21 - O.Z. 0050/~1050 butyl acrylate (10%) and methacrylic acid (30%) having a K value (according to H. Fikentscher) of 4~, 0.5 g of tripropylene glycol diacrylate, 700 mg of N-methoxypico-linium tosylate and 15 mg of Michler's ketone were dissolved in 8 g of methyl ethyl ketone and cast onto a 23 ~m thick sheet of polyethylene terephthalate in such a way ~hat, after drying, the photosensitive layer has a thickness of 40 ~m. The layer is covered for storage with a 30 ~m thick sheet of PE. To test the layer, the sheet of PE was peeled off, the composite of polyethylene terephthalate film and photosensitive layer was laminated with the photosensitive layer next to the copper onto a copper-clad circuit board substrate and irradiated in a Riston~ PC printer at ~0 mJ/cm2. After the polyethylene terephthalate film had been peeled off, the layer was developed in a spray washer with 1% strength sodium carbonate solution at 30C for 150 seconds, the irradi-ated areas of the light-sensitive layer proving com-pletely removable. The nonirradiated areas remained unchanged.
Comparative Examples 1 and 2 show that all 3 components are required for the po~itive effect to be observed.
Example 1 was repea~ed with 7.5 g o~ the reaction product prepared in accordance with the above method of preparation and 2.5 g of the copolymer de~cribed in Example l; ~hat is, the ethylenically unsaturated com-pound was not included. Following preparation and expo-sure as described in Bxample 1, neithar irradiated nor nonirradiated areas of the resist were removable within 5 minu~es. Nor did the irradiated areas become soluble on raising the exposuxe dose to 500 mJ~cm2.
CO~PARATIVE EXAMPLE 2 Example 1 was repeated using 9.5 g of the reac-tion product obtained in accordance with the abo~e method of praparation and 0.5 g o~ tripropylene glycol diacry-~2 ~`6 $
- 22 - O.Z. 0050/41050 late; that is, this time the addition of a compound having carboxyl groups was dispensed with. Preparation and testing were carried out as described in Examples 1 and 2. Again neither the irradiated nor the nonirradia ed areas of the resist were soluble following irradiation at from 5 to 500 mJ/cm2.
As in Example 1, 6.7 g of the compound prepared in accordance with the above method of preparation, 3 g of a copolymer of methyl methacrylate (57~), ethyl acrylate (20%) and methacrylic acid (23~) having a K
value (according to H. Fikentscher) of 44 and 0.3 g of tripropylene glycol diacrylate in 8 g of methyl ethyl ketone were admixed with 700 mg of N-metho~ypicolinium tosylate and 15 mg of Michler' 5 ketone. The solution obtained was processed as in Exampla 1. Following irradiation in a Riston~ PC printer at 35 mJ~cm2, the irradiated areas were developable with 1~ strength sodium carbonate solution in the course o~ gO ~econds. The 0 nonirradiated areas remained unchanged.
Example 1 wa~ repeated, except that the tripropy-lene glycol diacrylate was replaced by bisphenol A
diglycidyl ether diacrylate ox methyl polyglycol acrylate having an average chain length of 15 ethylene glycol units. The preparation and testing were carried out as described in Example l. Following irradiation at 30 mJ/cm2 the development time~ required in 1~ strength sodium carbona~e solution were 150 and llO second~, respec-tively. The nonirradiated areas of the resi~t remainedunchanged in the case o~ Example 3, whereas they were slightly swollen in Example 4.
\R2/
where Rl and R2 are identical or different and each is the divalent radical of a substituted or unsubstituted alkane, arene, ether, polyether, amine, polyamine, ester, polyester, amide or polyamide, R3 is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl or a derivative thereof, or a combination of at least one of the~e amines and at least one further primary or secondary amine different therefrom and as component iii) an aliphatic monoalcohol.
A suitable component tb) is in particular a c~rboxyl-containing compound having an average molecular weight F~
of above 10,000 and an acid number of from 50 to 300 mg of KOH/g. Particular preference i~ given to copolymers formed from an acid monomer and at least one hydrophobic monomer, the acid monomer being prelferably acrylic acid, methacrylic acid, crotonic acid or itaconic acid and the hydrophobic monomex being preferably a styrene, an acrylate or a methacrylate.
A suitable ethylenically monounsaturated or polyunsaturated compound (c) is an ~ ethylenically unsaturated carbonyl compound, pre~erably an acrylate or methacrylate.
Component~ ~b) and (c) may al~o be identical.
Preferred components (d) are benzophanone and derivatives thereof, hexaarylbisimidazole derivatives, N-alkoxypyridinium salts and mixture3 thexeof.
The ureido-containing reaction product ~a) o the radiation-sen3itive mixture according to the present invention is prepared by reacting the isocyanate com-3S ponent i~ with the amine component ii) and optionallywith the hydro~yl component iii) by using the groups which ars reactive towards isocyanate in an equivalent - 8 - O.Z. OOSO/~lOSO
amount or in excess, pre~erably in a rakio of from 1:1 to 4:1. Components i3 to iii) can be reacted simultaneously or in stages in any desired order.
~ This reaction can be carried out wi~hout a solvent or alternatively in an inert sol~ent, eg. ace-tone, tetrahydrofuran, dioxane, dichloromethane, toluene, methyl ethyl ketone or ethyl acetate. Other suitable solvents are the ethylenically monounsaturated or polyun-saturated compounds, if they are liquid.
The temperature for the reaction of the isocyan-ate groups is in general within the range from O to 100C, preferably from 20 to 70~C.
To speed up the reaction it is possible to use catalysts as described for example in Houben-Weyl, Methoden der organischen Chemie, volume XIV/2, p. 60f, Georg Thieme-Verlag, Stuttgart (1963) and Ullmann, Encyclopadie der technischen Chemie, volume 19, p. 306 (1981). Preference is given to tin-containing compounds such as dibutyltin dilaurate, tin(II) octoate and di-butyltin dimethoxide.
In general, the catalyst i~ used in an amount of from 0.001 to 2.5% by weight, pre~erably from O.OOS to 1.5~ by weight, based on the total amount of the reac-tants.
There now follow detailed observations concerning the formative components ~or preparing the reaction produc~ (a) and their use in the radiation-sensitive mixtures according to the present invention with com-ponents (b) to (d).
A suitable compound for use as a di- or polyiso-cyanate i) for the reaction of components i) to iii) is any compound which contains at least ~wo isocyanate groups capable of reaction with alcohols or primary or secondary amines. Particular preference is given to diisocyanatodiphenylmethane, diisocyanatotoluene (= toluylen~ diisocyanate), hexamethylene diisocyanato and isophorone diisocyanate, and also to oligomers ~2~ ~ $`
~ g - O.Z. 0050/41050 thereof of the isocyanurate and biuret type.
Suitable amino compounds ii) are all prLmary and secondary amines which are reactive toward isocyanate groups. Examples are n-butylamine, n-pentylamine, n-hexylamine, dodecylamine, benzylamine, ethylhexylamine,dibutylamine, ethylisopropylamine, l-methoxy-2-aminopro-pane, dibenzylamine, 1,5-dimethylhexylamine, dipentyl-amine, dihexylamine, cyclopropylamine, cyclopentylamine, methylbenzylamine and mixtures ther~of.
Of particular suitability are amines of the general formula R'HN-R-XH (I) and/or / R' \ (II) where, in the general formula (I) R'HN-R-XH (I) R is the divalen~ radical of a substitu~ed or unsubstituted alkane, for example of from ~ to 10 carbon atoms, such as -(CH2)p- where p is from 2 to 10~ -CH2-C(CH3)2-CH2- or -CH(CH3)-C~I2-, of an arene, for example phenyl~ne, of a substituted arene, for example -(CH2)r~-C6H3(OX)- where r is from 1 to 6, preferably 2, of an ether, for example -(CH2-CHRIV-O-)q-CH2-CHRIv- where q is from 1 to 5, and RIV i9 H or alkyl of from 1 to 4 carbon atoms, of an amine, for example of from 2 to 20 carbon atoms, eg. -(CH2)3-N(CH3)-(CH2)3-, f a polyamine, for example -(CH2-CH2-NH)o- where o is from 2 to 5, of an ester, for example of from ~ to 20 carbon atoms, eg. -(CH2)2-COO-(CH2),- where s is from 2 to 6, -CH2-COO-CH2-CH(C~3)-, or of an amide, for example of from 4 to 20 carbon atoms, e g . - ( C H 2 ) 2 - C O N H - C H 2 ~ o r -(CH2)2-CoN~-(c}~2)5-NHoc-(cH2)2-;
R' is hydrogen, alkyl, for example of from 1 to 30, ~ ~ 2 ~
- 10 - O.Z. 0050/41050 preferably from 1 to 10, carbon atoms, eg.
methyl, ethyl, propyl, butyl and isomers thereof, cyclohexyl, aryl, for example of from 6 to 18 - carbon atoms, preferably phenyl, naphthyl, aralkyl, for example of from 7 to 20 carbon atoms, eg. benzyl, 1-phenylethyl, l-methyl-3-phenylpropyl, hydroxyalkyl, for example of from 2 to 10 carbon atoms, eg. hydroxyethyl, hydroxy-propyl, hydroxybutyl, aminoalkyl, for example of from 2 to 10 carbon atoms, eg. aminoethyl, aminopropyl, dimethylaminobutyl, dimethyl-aminoneopentyl, mercaptoalkyl, for example of from 2 to 10 carbon atoms, eg. mercaptoethyl, or derivatives of these groups - derivatives being in the present case alkyl-, aryl-, halogen~, carboxyl-, nitro-, nitrile-, sulfoxyl--, amino-, alkoxy- or aryloxy-substituted gro~ps of the aforamentioned kind - or the monovalent r~dical K~O-(CH2)n-CHR"~m where n :is from l to 3, m is from 1 to 10 and R" is H or Cl-C4-alkyl, or isomers thereof as obtainahle by Yimple addition or polyaddit~on o~ cyclic ethers, eg. ethylene oxide, propylene oxide or ~etrahydro~uran, for ex~npLe hydroxyethyloxyethyl;
X is O, S or NR"', where R"' is hydrogen, al~yl, for example of from 1 to lO carbon atoms, eg.
methyl or ethyl, aryl, ~or example phenyl or naphthyl, aralkyl, for example benzyl or phenyl-ethyl, hydroxyalkyl, ~minoalkyl or mercaptoalkyl, with alkyl groups which may each contai~ from 1 to 10 carbon atoms, or derivatives o~ these groups of the type mentioned under R'.
Examples of compounds of the general formula R'HN-R-XH are ethylenediamine, butanediamine, 3S neopentanediamine, polyoxypropylenediamines, polyoxyethylenediamines, N-ethylethylenediamine, diethylenetriami.ne, monoisopropanolamine.
2 ~ 2 3 ~ ~ ~
~ O.Z. 0050/41050 Particular preference is gi~en to ethanolamine, diethanolamine, diisopropanolamine, neopentanol-amine, ethylisopropanolamine, ltylethanolamine ~ and 2-mercaptoethylamine.
In the general formula (II) / Rl~
HN ~ R3 (II) R1 and R2 are identical or different and each is in particular the divalent radical of a sub-stituted or unsubstituted alkane, for example of from 2 to 4 carbon atoms, eg. -tCH2)t- where t is from 1 to 4, of an arene, for example o-phenylene, or an ether, for example of from 2 to 4 carbon atoms, eg. -CH2-O-CH2-;
R3 is a hydrogen, alkyl, aryl, aralkyl, hydroxy-alkyl, aminoalkyl, mexcaptoalkyl or a derivative thereof of the type mentioned under R'. Praferred compounds of the general formula (II) R1 \
HN NR3 ~II) \ R2/
are piperazine and 1-(2-hydroxyethyl)piperazine.
Similarly, it i al30 pos~ible to use mixtures of the amino compounds mentioned under ii), whose reaction with isocyanate may be effected simultaneously or in stages.in any desired order. Preferred combinations consis~ of amines o~ the general for~ulae (I) and/or (II) and primary or socondary amines. Particularly pxaferred combination~ are hydroxyalkylamino compounds, eg. diiso-propanolamine, diethanolamine or ethanolamine, with primary or secondary aliphatic amines, eg. butylamine or dibutylamine.
Suitable compounds iii) for inclusion as having at least one hydro~yl function are all mono- and multi-~unctional alcohols which are reactive toward isocyanate groups. Examples are mono-, di- and trialcohol~ of ~rom ~2~
- 12 - O.Z. 0050/41050 1 to 20 carbon atoms, such as methanol, ethanol, n-propanol, isopropanol, butanol, 1-methoxybutanol, ethy-lene glycol, propylene glycol, butanediol, hexanediol, cyclohexanedimethanol, glycerol, trimethylolpropane, etc.
Preference is given to aliphatic alcohols of from 1 to 6 carbon atoms.
(b) Suitable organic compounds for inclusion as having one or more carboxyl groups are low molecul~r weight carboxylic acids, for example monocarboxylic or dicar-boxylic acids containing from 1 to 20 carbon atoms, eg.adipic acid, phthalic acid, terephthalic acid, malonic acid, succinic acid or maleic acid. A particularly suitable component (b) is a carboxyl-containing compound which, owing to its composition and its molecular weight, has good film forming properties. Preference i5 given to polymers having an av~rage molecular weight ~ of above 10,000, preferably of from 15,000 to 300,000, and an acid number which is within the range from 50 to 300 mg of KOH/g. Particular preference i~ given to copolymers formed from an acid monomer, eg. ac:rylic acid, methacry-lic acid, crotonic acid or itaconic acid, and one or more hydrophobic comonomers, eg. styrene, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate or methyl meth-acrylate. Of particular ~ui~:ability are also styrene/maleic anhydride copolymers which have been partially ecterified with lower alcohol~. The composition of these copolymers is chosen in such a way that they are compatible with component ta).
The mixing ratio of component ~b) to component (a) is chosen in ~uch a way that the radiation-sensitive mixtures according to the present invention are insoluble in the developer used but become ~oluble therein on irradia~ion. The concentration range in which this is achieved naturally depen~s strongly on the compesition of component (b). In general, a favorable concentration range for (b) is from S to 40% by weight, particularly preferably from 10 to 30~ by weight, based on the total ~%3~
- 13 - O.Z. OOS0/4105 weight of the radiation-sensitive mixture.
tc) Suitable ethylenically monounsaturated or poly-unsaturated compounds are low molecular weight or oligo-meric compounds having at least one ethylenically un-saturated double bond. The compounds are selected foxcompatibility with the other constituents of the radiation-sensitive mixture according to the present invention. P~eference i5 given to ~,~-unsaturated car-bonyl compounds. Particular pre~erence is given to acrylates and methacrylates, for example alkyl (meth)-acrylates, alkylpolyethylene or arylpolyethylene glycol (meth)acrylates at from 2 to 10 propylene glycol units, alkylpolypropylene or arylpolypropylene glycol (meth)-acrylates having from 2 to 10 propylene glycol units, polyethylene glycol di(meth)acrylates having ~rom 2 to 10 ethylene glycol units, polypropylene glycol di(meth)-acrylates having from 2 to 10 propylene glycol unit~ or reaction products of bisphenol A, epichlorohydrin and (meth)acrylic acid. The ethylenically unsaturated com-pounds (c) are preferably added to the radiation-sensi-tive mixture in a concentration o from 1 to 40~ by weight, par~icularly pro~erably ~rom 3 to 25% by weight, based on the total weight of the radiation-~ensitive mixture. A high concentration, ie. more than 15~ by weigh~, is chosen in particular when, following a first exposure step and the removal of the irradiated material in a d~veloper, a crosslinking is to be brought about in a second, longer exposure ~tep in order that in this way the mechanical stability, for example printing plates, be improved.
It is also possible, furthermore, to combine components (~) and (c) in one compound, ie. to use a carboxyl-containing ethylenically unsaturated compound.
Examples of such compounds are fumaric acid, maleic acid, (meth)acrylic acid and reaction products of hydroxyl-containing acrylates, for example ~-hydroxyalkyl acry-late~, as obtained by reacting epoxy compounds with 2~2~$~
- I4 - O.z. OOSa/41050 acrylic acid or incomplete esterification of di- and polyalcohols with acrylic acid, or hydroxy-functional urethane acrylates obtained by reacting an ~xcess of di-or~polyalcohols with isocyanate compounds, with acid anhydrides, eg. maleic or phthalic anhydride. Preference is also given here to using polymeric compounds which have good film forming properties owing to their mole-cular weight. Such polymeric compounds which contain not only carboxyl groups but also ethylenically unsaturated groups can be obtained for example from the copolymers of ~tyrene, (meth)acrylate and (meth)acrylic acid mentioned above as component (b) by reaction with glycidyl acrylate or methacrylate. This re~ction is preferably carried ou~
in such a way that 5 to 40% of the free carboxyl groups of the copolymer are converted.
Another possible way of preparing polymers having carboxyl groups and ethylenically unsaturatecl groups comprises including hydroxyalkyl (meth)acrylate units in the polymer in addition to the abovlementioned comonomers and to react the hydroxyl groups in a second step with anhydrides of unsaturated carboxylic acids, eg. maleic anhydride or methacrylic anhydride. The skilled worker will o~ course be ~amiliar wi~h still further methods for preparing ~he polymer~ mentioned. The compounds men-tioned, which contain not only carboxyl groups but alsoethylenically unsaturated groups, are preferably used in a concentration of from 5 to 60~ by weight, particularly preferably from 10 to 40% by weight, based on the total weight o~ the radia~ion-sensitive mixture.
(d) The photoinitiators which may be included in the radiation-sensitive mixture according to the present invention are the photoinitiators and photoinitiator systems which are customary and kn~wn per se for light-sensitive photopolymerizable recording materials. Speci-fic examples are: benzoin, benzoin ethers, in particularbenzoin alkyl ethers, substituted benzoins, alkyl ethers of substituted benzoins, eg. ~-methyl-benzoLn alkyl ~3~
- 15 - O.Z. 0050/41050 ethers, or ~-hydroxymethylbenzoin alkyl ethers; benzils, benzil ketals, in particular benzil dimethyl ketal, benzil methyl ethyl ketal or benzil methyl benzyl ketal;
the acylphosphine oxide compounds known for use as effective photoinitiators, eg. 2,4,6-trimethylbenzoyl-diarylphosphine oxide; benzophenone, derivatives of benzophenone,4,4'~dime~hylaminobenzophenone,derivatives of Michler's ketone; anthraquinone and substituted anthraquinones; aryl-substituted imidazoles or derivatives thereof, eg. 2,4,5-triarylimidazole dimers;
thioxanthone derivatives, the active photoinitiator acridine or phenacine derivatives and N-alkoxypyridinium salts and derivatives thereof. Suitable pho~oini~iators also include diazonium salts, eg. p-phenylamino-benzenediazonium hexafluorophosphatel iodonium salts, eg.diphenyliodonium tetrafluoroborate, or sulfonium salts, eg. triphenylsulfonium hexafluoroarsenate. Examples of initiator systems are combinations of the aforementioned initiators with sensitizing a~sista~nts or activators, in particular tertiary amines. Typic:al examples of such initiator systems are combinations of benzophenone or benzophenone derivatlves with tertiary amine~, such as triethanolamine or Michler's ketone; or mixtures of 2,4,5-triarylimidazole dimers and Michler's ketone or the leuco bases of triph~nylmethane dyes. The choice of suitable photoinitiator~ or photoinitiator systems i5 known to the skilled worker. Particularly preferred photoinitiators are Michler's ketone, ben20phenone, hexaarylbisimidazole derivatives and N-alkoxypyridinium salts. It is also very advantageouR to use mixtures of said photoinitiators. The photoinitiators or photoiniti-ator systems are in general present in the light-sensitive recording layer in amounts of from 0.1 to lO~
by weight, based on the radiation-sensitive mixture.
(e) Suitable additives andJor auxiliaries (e) or possible inclusion in the radiation-sensitive mixture according to the present invention include for example .. . ,.. ~ . ~. ...
- 16 - O.Z. 0050/41050 dyes and/or pigments, photochromic compounds and systems, sensitometric regulators, plasticizers, flow control agents, delusterants, lubricants, basic components and the like. Examples of dyes and/or piqments, which may serve not only as contrast agents but also to reinforce the layer, include inter alia srilliant Green ~C. I . 42 040 ), Victoria Pure Blue FGA, Victoria Pure Blue 80 (C.I.
42 s9s)r Victoria Blue B (C.I. 44 045), Rhodamine 6 G
(C.I. 45 160), triphenylmethane dyes, naphthalimide dyes and 3'-phenyl-7-dimethylamino-2,2'-spirodi(2H-l-benzopyran). Photochromic or color change systems which on irradiation with actinic light undergo a reversible or irreversible color change without thereb~ interfering with the photopolymerization process are for example leuco dyes together with suitable activators. Examples of leuco dyes are the leuco bases of triphenylmethane dyes, such as crystal violet leuco base and malachite green leuco base, leuco Basic Blue, leuco pararosaniline, leuco Patent Blue A or V; it is also possible to use Rhodamine B base. Suitable acti~ators for these photochromic compound~ include inter alia organic haloqen compounds which eliminate the halogen radicals on irxadiation with actinic light or hexaarylbisimida2:01es. Suitable color change systems are also described in DE-A-38 24 551.
Particularly suitable color change systems are those where the color intensity decreases on irradiation, for example Sudan dyes, polymethine dye~ or azo dyes combined with suitable photoinitiators. Su.itable sensitometric regulators include compounds such as 9-nitroanthracene, lO,lO'-bisanthxone, phenazinium, phenoxazinium, acridinium or phenothiazinium dyes, in particular com-bined with mild reducing agents, l,3-dinitrobenzane3 and the like. Suitable plasticizers are the known and cus-tomary low or high molecular weight esters, such as phthalates or adipates J toluenesulonamide or tricresyl phosphatQ. Suitable basic components are additions of amines, in particular tertiary amines, eg. triethylamine - 17 - O.Z. 0050/41050 or triethanolamine, or alkali metal or alkaline earth metal hydroxides and carbunates. The additives and/or assistants are present in the radiation-sensitive mixture in~the effective amounts known and customary for these S substances. However, ~heir amount should in general not exceed 30% by weight, preferably 20~ by weight, based on the radiation-sensitive mixture.
A film or coating can be prepared by dissolving the above-described radiation-sensitive mixture in a solvent and then applying the resulting mixture to a permanent or temporary support by casting, with or without a doctor blade, spin coating, roller coating or some other technique.
Suitable solvents are for example aromatic hydrocarbons, low molecular weight ketones, alcohols, ethers, esters and chlorocarbons.
A suitable support for the radiation-sensitive coatings according to the present invention i4 virtually any material which is customary in printing and in the fabrication of circuit boards for the electronics in-dustry. However, an impor~ant condition i~ that the support be inert, ie. that it should not react with the radiation-sensitive mixture used for preparing the coating.
Suitable support materials are for example steel, aluminum alloys, mechanically, chemically or electro-chemic~lly roughened aluminum, silicon, polyesters and other plastics. The layer thicknass here may vary within wide limits. If the radiation-sensitive mixture Ls used for examp , as a letterpress or intaglio printing plate, it will typically be within the ranga from 50 to 500 ~m, if used as a photoresist for the ~abrication of printed circuits within the range rom ~0 to lO0 ~m and i~ used as a photoresist for structuring semicondu~tor materials within the range from 0.3 to 5 ~m. If the radiation-sensitive mixture according to the present invention is used as an offset printing plate, the coating will be .~, ~
g - 18 - O.Z. 0050~41050 prepared in such a way as to prod~ce dry layer weights of from 0.5 to 5 g/sqm.
The radiation-sensitive mixtures according to the present invention are advantageous for producing printing plates or resist patterns in a conventional manner. To this end the light-sensitive recording layer - in the case of photoresist films and laminating materials after lamination to the substrate to be protected - is sub-jected to imagewise exposure with ac~inic light, suitable sources of which are the customary ones, such as W
fluorescent tubes, mercury high, medium or low pressure lamps, superactinic fluorescent tubes, pulsed xenon lamps or even W lasers~ argon lasers and the like. The wave-length emitted by the light sources should in general be within the range from 230 to 450 nm, preferably within the range from 300 to 420 nm, and be adapted in par-ticular to the characteristic absorption of the photo-initiator present in the photopolymerizable recording layer.
Following imagewise exposure, the printing plate or resist pattern is developed by washing out the irra-diated areas of the recording layer with water or pre~er-ably an aqueous alkali. ~he proce~is of development can take the form of washing, spraying, rubbing, brushing etc. The recording elements according to the present invention here show a wide exposure latitude and a very low ovexwa~h sen~itivity. Suitable developers are aqueous alkalis which to set the best pH, in general pH 8-14, preferably a pH within the range from 9 to 13, contain alkaline substance~, for example borax, disodium hyd-rogenphosphate, sodium carbonate, alkali metal hydroxides or organic bases, such as di- or triethanolamine, dis-solved in water. The aqueouq alkali developers may also contain buffer salts, for example water-soluble alkali metal phosphates, silicate~, borates, acetates or benzo-ates. Further suitable constituents of developer~ ars wetting agents, preferably anionic wetting agents, and $ ~ ~
- 19 - O.Z. 0050/41050 possibly water-soluble polymers, for example sodium carboxymethylcellulose, polyvinyl alcohol, polysodium acrylate and the like. Although the recording elements according to the present invention are in general washe~
j out with water or aqueous alkali, it is of course pos-sible in principle, although not strictly necessary, that the developer should _lso contain a small amount of water-soluble organic solvent, for exampl~ an aliphatic alcohol, acetone or tetrahydrofuran.
The radiation-sensitive mixtures according to the present invention can be structured for example by high-energy radiation such as electron bea~s or X-rays, when they show their very high sensitivity to radiation. If used in this way it is generally possible to dispense with the addition of a separate initiator system. If, by contrast, the mixtures according to the present invention are to be structured by visible or W light, as is customary for production of printing plates and photo-resists, it is advisable to add suitable photoinitiators whose spec~ral sensitivity matches the emi~ted spectrum of the light source used. The~e mixtures likewise show very high ligh~ sensitivity or positive-working systems, which corresponds to the light sensitivity of commercial negative systems of 9im~ lar thickness. This high light sensitivity is obtained without any need for additional operations, for example the thermal aftertreatment which is necessary with many othar positive ~y~tems. Similarly, the developers used correspond to those used for negative-working layers, so that the recording layers according to the presen~ invention are complately compat-ible with conventional system~. The radiation-sensitive recording layers according to the present invention are highly suitable for multiple exposures. This makes it possible in many applications to save process steps.
Multiple exposures are not possible with all photopoly-merizable systems, including many posi~ive systems, for fundamental reasons. The radiation-sensitive mixtures ~ 20 - O.Z. 0050/41050 according to ~he present invention also ha~e the inter~
esting property of acting as positive systems for short exposure times but as crosslinkable systems for long exposure times. This effect occurs in particular when the radiation-sensitive mixture con~ains the ethylenically monounsaturated or polyunsaturated compounds c~ in an amount of > 15~ by weight. This property can be utilized after a first, imagewise exposure step with a short exposure ~ime and after removal of the irradiated areas in a developer for initiating a crosslinking reaction in a second, not nacessarily imagewise exposure step using a distinctly longer exposure tLme. In this way it is possible to improve the mechanical properties, for example of printing plates.
The invention is illustrated in more detail by the Examples which follow.
In the method of preparation and in the Examples, the parts ancl percentages are by weight, unless otherwise stated.
Preparation of the reaction products (a) to be used according to the present invention"
Method of preparation 154.8 g of di-n-butylamine (1.2 mol) are added dropwise to a mixture of 266.4 g of isophorone diisocyan-ate (1.2 mol) and 251 g of methyl ethyl ketone at 16-18C
with ice cooling for 30 minutes. Following a reaction time o~ 30 minutes at a maximum temperature of 46C, 150.4 g of diisopropanolamine (1.13 mol) are added dropwise at 46C in the course of 20 minutes, during which the temperature rises to 50C. The reaction ends ater 4 hours at 50C. The 67.8~ strength solution has a viscosity of 500 mPa.Y (measured at 23C with a cone/
plata viscometar).
EXAMPL~ 1 ~5 7 g of tha reaction product prepared in accor-dance with the above method of preparation, 2.5 g of a copolymer of styrene (25~), methyl methacr~late (35~), - 21 - O.Z. 0050/~1050 butyl acrylate (10%) and methacrylic acid (30%) having a K value (according to H. Fikentscher) of 4~, 0.5 g of tripropylene glycol diacrylate, 700 mg of N-methoxypico-linium tosylate and 15 mg of Michler's ketone were dissolved in 8 g of methyl ethyl ketone and cast onto a 23 ~m thick sheet of polyethylene terephthalate in such a way ~hat, after drying, the photosensitive layer has a thickness of 40 ~m. The layer is covered for storage with a 30 ~m thick sheet of PE. To test the layer, the sheet of PE was peeled off, the composite of polyethylene terephthalate film and photosensitive layer was laminated with the photosensitive layer next to the copper onto a copper-clad circuit board substrate and irradiated in a Riston~ PC printer at ~0 mJ/cm2. After the polyethylene terephthalate film had been peeled off, the layer was developed in a spray washer with 1% strength sodium carbonate solution at 30C for 150 seconds, the irradi-ated areas of the light-sensitive layer proving com-pletely removable. The nonirradiated areas remained unchanged.
Comparative Examples 1 and 2 show that all 3 components are required for the po~itive effect to be observed.
Example 1 was repea~ed with 7.5 g o~ the reaction product prepared in accordance with the above method of preparation and 2.5 g of the copolymer de~cribed in Example l; ~hat is, the ethylenically unsaturated com-pound was not included. Following preparation and expo-sure as described in Bxample 1, neithar irradiated nor nonirradiated areas of the resist were removable within 5 minu~es. Nor did the irradiated areas become soluble on raising the exposuxe dose to 500 mJ~cm2.
CO~PARATIVE EXAMPLE 2 Example 1 was repeated using 9.5 g of the reac-tion product obtained in accordance with the abo~e method of praparation and 0.5 g o~ tripropylene glycol diacry-~2 ~`6 $
- 22 - O.Z. 0050/41050 late; that is, this time the addition of a compound having carboxyl groups was dispensed with. Preparation and testing were carried out as described in Examples 1 and 2. Again neither the irradiated nor the nonirradia ed areas of the resist were soluble following irradiation at from 5 to 500 mJ/cm2.
As in Example 1, 6.7 g of the compound prepared in accordance with the above method of preparation, 3 g of a copolymer of methyl methacrylate (57~), ethyl acrylate (20%) and methacrylic acid (23~) having a K
value (according to H. Fikentscher) of 44 and 0.3 g of tripropylene glycol diacrylate in 8 g of methyl ethyl ketone were admixed with 700 mg of N-metho~ypicolinium tosylate and 15 mg of Michler' 5 ketone. The solution obtained was processed as in Exampla 1. Following irradiation in a Riston~ PC printer at 35 mJ~cm2, the irradiated areas were developable with 1~ strength sodium carbonate solution in the course o~ gO ~econds. The 0 nonirradiated areas remained unchanged.
Example 1 wa~ repeated, except that the tripropy-lene glycol diacrylate was replaced by bisphenol A
diglycidyl ether diacrylate ox methyl polyglycol acrylate having an average chain length of 15 ethylene glycol units. The preparation and testing were carried out as described in Example l. Following irradiation at 30 mJ/cm2 the development time~ required in 1~ strength sodium carbona~e solution were 150 and llO second~, respec-tively. The nonirradiated areas of the resi~t remainedunchanged in the case o~ Example 3, whereas they were slightly swollen in Example 4.
Claims (15)
1. A radiation-sensitive mixture formed from (a) a ureido-containing reaction product, (b) at least one organic compound which contains one or more carboxyl groups, (c) at least one ethylenically monounsaturated or polyunsaturated organic compound, (d) optionally, a photoinitiator or photoinitiator system and (e) optionally, further additives and auxiliaries, wherein component (a) is a reaction product of i) at least one di- or polyisocyanate and ii) at least one organic compound having at least one primary or secondary amino group and iii) optionally, one or more compounds having at least one hydroxyl group, the number of NCO groups in component i) being equal to or less than the number of groups in ii) and iii) which are reactive therewith.
2. A radiation-sensitive mixture as claimed in claim 1, wherein a diisocyanate was used as component i) for preparing the ureido-containing reaction product (a).
3. A radiation-sensitive mixture as claimed in claim 1 or 2, wherein the ureido-containing reaction product (a) was prepared using as component ii) one or more primary and or secondary amines of the general formula (I) R'HN-R-XH (I) where R is the divalent radical of a substituted or unsub-stituted alkane, arene, ether, polyether, amine, poly-amine, ester, polyester, amide or polyamide, R' is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl, a derivative thereof or the monovalent radical H?O-(CH2)n-CHR"?m where n is from 1 to 3, m is from 1 to 10 and R" is H or C1-C4-alkyl, or an isomer thereof, - 24 - O.Z. 0050/41050 X is O, S or NR''', R''' is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl or a derivative thereof, and/or at least one amino compound of the general formula (II) (II) where R1 and R2 are identical or different and each is the divalent radical of a substituted or unsubstituted alkane, arene, ether, polyether, amine, polyamine, ester, polyester, amide or polyamide, R3 is hydrogen, alkyl, aryl, aralkyl, hydroxyalkyl, aminoalkyl, mercaptoalkyl or a derivative thereof.
4. A radiation-sensitive mixture as claimed in claim 1, wherein the ureido-containing reaction product (a) was prepared using as component ii) a combination of at least one amine as set forth in claim 3 and at least one further primary or secondary amine different therefrom.
5. A radiation-sensitive mixture as claimed in any of the preceding claims, wherein the ureido-containing reaction product was prepared using as component iii) an aliphatic monoalcohol.
6. A radiation-sensitive mixture as claimed in any of the preceding claims, wherein component (b) is a carboxyl-containing compound having an average molecular weight ?n of above 10,000.
7. A radiation-sensitive mixture as claimed in any of the preceding claims, wherein component (b) is a carboxyl-containing compound having an acid number of from 50 to 300.
8. A radiation-sensitive mixture a claimed in any of the preceding claims, wherein component (b) is a copolymer of an acid monomer and at least one hydrophobic monomer.
9. A radiation-sensitive mixture as claimed in claim - 25 - O.Z. 0050/41050 8, wherein the acid monomer used was acrylic acid, methacrylic acid, crotonic acid or itaconic acid.
10. A radiation-sensitive mixture as claimed in claim 8 or 9, wherein the hydrophobic monomer used was at least one from the group of the styrenes, acrylates and meth-acrylates.
11. A radiation-sensitive mixture as claimed in any of the preceding claims, wherein the ethylenically monounsaturated or polyunsaturated compound (c) is an .alpha., .beta.-ethylenically unsaturated carbonyl compound.
12. A radiation-sensitive mixture as claimed in any of the preceding claims, wherein the ethylenically unsaturated organic compound (c) is an acrylate or methacrylate.
13. A radiation-sensitive mixture as claimed in claim 1, wherein the components (b) and (c) are identical.
14. A radiation-sensitive mixture as claimed in any of the preceding claims, wherein component (d) is benzo-phenone or a derivative thereof, a hexaarylbisimidazole derivative, an N-alkoxypyridinium salt or a mixture thereof.
15. A radiation-sensitive mixture as claimed in any of the preceding claims, whose solubility in water or aqueous alkali increases on irradiation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3927628.7 | 1989-08-22 | ||
| DE3927628A DE3927628A1 (en) | 1989-08-22 | 1989-08-22 | RADIATION-SENSITIVE MIXTURE |
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| Publication Number | Publication Date |
|---|---|
| CA2023668A1 true CA2023668A1 (en) | 1991-02-23 |
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| AU (1) | AU6117590A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1464942A (en) * | 1973-02-01 | 1977-02-16 | Polychrome Corp | Polymers process for their preparation and their use in photo polymerizable compositions and elements for relief images |
| JPS58140737A (en) * | 1982-02-15 | 1983-08-20 | Toyobo Co Ltd | Photosensitive resin composition |
-
1989
- 1989-08-22 DE DE3927628A patent/DE3927628A1/en not_active Withdrawn
-
1990
- 1990-08-14 EP EP19900115568 patent/EP0414104A3/en not_active Withdrawn
- 1990-08-20 JP JP2217292A patent/JPH03102356A/en active Pending
- 1990-08-21 CA CA002023668A patent/CA2023668A1/en not_active Abandoned
- 1990-08-21 AU AU61175/90A patent/AU6117590A/en not_active Abandoned
- 1990-08-22 KR KR1019900012960A patent/KR910004708A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| KR910004708A (en) | 1991-03-29 |
| AU6117590A (en) | 1991-02-28 |
| JPH03102356A (en) | 1991-04-26 |
| EP0414104A3 (en) | 1991-10-16 |
| DE3927628A1 (en) | 1991-02-28 |
| EP0414104A2 (en) | 1991-02-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |