Source: http://patents.com/us-7993809.html
Timestamp: 2018-06-20 20:59:22
Document Index: 6714941

Matched Legal Cases: ['Application No. 200717494', 'Application No. 10', 'Application No. 095118300', 'Application No. 200680017652', 'Application No. 2006', 'Application No. 10']

US Patent # 7,993,809. Photosensitive resin composition, photosensitive element, method for forming resist pattern and method for producing printed wiring board - Patents.com
United States Patent 7,993,809
Miyasaka , et al. August 9, 2011
Photosensitive resin composition, photosensitive element, method for forming resist pattern and method for producing printed wiring board
A photosensitive resin composition comprising: (A) a binder polymer; (B) a photopolymerizable compound that has an ethylenically unsaturated bond; and (C1) a compound represented by general formula (1) below, ##STR00001## wherein, at least one R represents a C.sub.1-10 alkoxy group or a C.sub.1-12 alkyl group; the sum of a, b, and c is 1 to 6; and when the sum of a, b, and c is 2 to 6, each R may be the same as or different from one another.
Inventors: Miyasaka; Masahiro (Hitachi, JP), Kumaki; Takashi (Hitachi, JP)
Appl. No.: 11/915,169
PCT No.: PCT/JP2006/310134
PCT Pub. No.: WO2006/126480
May 23, 2005 [JP] P2005-150133
Apr 06, 2006 [JP] P2006-105416
Current U.S. Class: 430/270.1 ; 430/311; 430/905; 430/913; 430/915; 430/920; 430/945
Current International Class: G03F 7/00 (20060101); G03F 7/004 (20060101); G03F 7/028 (20060101)
Field of Search: 430/270.1,913,905,945,915,920,311
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Translation of the International Preliminary Report on Patentability for Application No. PCT/JP2006/310134, dated Dec. 6, 2007. cited by other .
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1. A method of forming a resist pattern, comprising: forming a photosensitive layer comprising a photosensitive resin composition on a substrate, wherein the photosensitive resin composition comprises: (A) a binder polymer; (B) a photopolymerizable compound that has an ethylenically unsaturated bond; (C1) a compound represented by general formula (1) below, ##STR00003## wherein, at least one R represents a C.sub.4-12 alkyl group; the sum of a, b, and c is 1 to 6; and when the sum of a, b, and c is 2 to 6, each R may be the same as or different from one another; and (C2) a 2,4,5-triarylimidazole dimer or a derivative thereof, wherein the content of the component (C1) is 0.05 to 0.8 mass parts per 100 mass parts of the total content of components (A) and (B), and the content of the component (C2) is 3 to 5 mass parts per 100 mass parts of the total content of components (A) and (B) exposing prescribed regions of the photosensitive layer to light by a direct exposure imaging technique; and developing the exposed photosensitive layer to form a resist pattern.
2. The method of forming a resist pattern according to claim 1, wherein component (A) comprises an acrylic-type polymer that has as constituent units thereof a monomer unit derived from acrylic acid and/or methacrylic acid and a monomer unit derived from alkyl ester of acrylic acid and/or alkyl ester of methacrylic acid.
3. The method of forming a resist pattern according to claim 1, wherein the content of the component (B) is 20 to 80 mass parts per 100 mass parts of the total content of components (A) and (B).
4. The method of forming a resist pattern according to claim 1, wherein the sum of a, b, and c is 1 or 2.
5. The method of forming a resist pattern according to claim 1, wherein said direct exposure imaging technique includes exposure to laser light having a peak in the wavelength range from at least 350 nm to less than 440 nm.
6. A method of producing a printed wiring board, comprising: performing the method of forming a resist pattern according to claim 1; and forming a conductor pattern on the substrate based on said resist pattern.
7. The method of forming a resist pattern according to claim 1, wherein the component (C2) is at least one selected from the group consisting of 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, and 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer.
8. The method of forming a resist pattern according to claim 1, wherein the photosensitive resin composition further includes (D) leuco crystal violet.
9. The method of forming a resist pattern according to claim 8, wherein the leuco crystal violet is included in an amount of 0.05 to 5 mass parts per 100 mass parts of the total of components (A) and (B).
10. The method of forming a resist pattern according to claim 1, wherein a weight-average molecular weight of component (A) of the photosensitive resin composition is 40000 to 80000.
The development of technology that enables even higher densities for the wiring of electronic circuits is being actively pursued in particular in the surface mounting technology sector, for example, in connection with printed wiring boards, semiconductor packages, and so forth. There is demand in this sector that the conductor pattern constituting the wiring be formed on the scale of 10 .mu.m or less. The photosensitive resin composition used in photolithography must therefore provide resolution on the scale of 10 .mu.m or less.
Ever higher sensitivities are also being required of the photosensitive resin composition. Escalating wiring densities have a tendency to bring out the problem of a voltage drop due to the resistance of the power lines. An effective response to this problem is to thicken the conductor layer that forms the wiring to at least about 10 .mu.m by increasing the film thickness of the resist pattern. Additional increases in sensitivity are then required of the photosensitive resin in order to be able to form the thicker resist patterns at high productivities.
In formula (1), at least one R represents a C.sub.1-10 alkoxy group or a C.sub.1-12 alkyl group; the sum of a, b, and c is 1 to 6; and when the sum of a, b, and c is 2 to 6, each R may be the same as or different from one another.
When R in the compound represented by general formula (1), supra, represents a C.sub.1-10 alkoxy group or a C.sub.1-3 alkyl group, this R is preferably a methoxy group and/or an isopropyl group and the sum of a, b, and c is preferably 1 or 2.
In addition, when R in the compound represented by general formula (1), supra, represents a C.sub.4-12 alkyl group, this R is preferably at least one alkyl group selected from the group consisting of an n-butyl group, a tert-butyl group, a tert-octyl group, and a dodecyl group. The pyrazoline derivatives having these substituents provide a clearly satisfactory sensitivity and resolution for the photosensitive resin composition.
Here, the phrase "having a peak" means that the intensity of the light exhibits a maximum value in the prescribed wavelength range.
The component (C1) used in the photosensitive resin composition of the present invention preferably has a wavelength of maximum absorption of from at least 370 nm to less than 420 nm. This "wavelength of maximum absorption" denotes the wavelength at which the absorbance achieves its highest value. One means for obtaining a photosensitive resin composition suitable for the aforementioned direct imaging exposure using the components present in conventional photosensitive resin compositions comprises simply increasing the addition of the photopolymerization initiator in order to increase the absorbance over all wavelengths, thereby securing the sensitivity by also raising the absorbance for light having a peak in the wavelength range from at least 390 nm to less than 440 nm. However, conventional photosensitive resin compositions that contain 4,4'-bis(diethylamino)benzophenone as initiator have a wavelength of maximum absorption around 365 nm. Due to this, light having a peak in the wavelength range from at least 390 nm to less than 440 nm is located at the foot or fringe of the absorbance peak (wavelength of maximum absorption: 365 nm) of such a photosensitive resin composition. This results in a large change in sensitivity for a shift of approximately several nm in the wavelength of the irradiated light. On the other hand, the laser light used, for example, in direct imaging exposure, exhibits a wavelength distribution to a certain degree, and an oscillation width of approximately several nm can occur in the wavelength at the time of irradiation. Given this, the stability or consistency of the sensitivity will tend to be reduced in those cases where nothing more than a simple increase in the addition of the photopolymerization initiator has been carried out.
1 . . . photosensitive element 10 . . . support 14 . . . photosensitive layer
Suitable embodiments of the present invention are described in detail hereinbelow, as necessary with reference to the figures. The same reference symbols are assigned to the same elements throughout the figures and redundant descriptions have been omitted. Positional relationships, such as top and bottom, left and right, and so forth, are based on the positional relationships shown in the figures, unless stated otherwise. In addition, the dimensional ratios depicted in the figures are not limited to the graphically represented ratios. In this Description, "(meth)acrylic acid" denotes "acrylic acid" and the "methacrylic acid" corresponding thereto; "(meth)acrylate" denotes "acrylate" and the "methacrylate" corresponding thereto; the "(meth)acryloxy group" denotes the "acryloxy group" and the "methacryloxy group" corresponding thereto; and the "(meth)acryloyl group" denotes the "acryloyl group" and the "methacryloyl group" corresponding thereto.
There are no particular limitations on the component (A) binder polymer as long as it is a polymer that enables the uniform dissolution or dispersion of the other components of the resin composition. Component (A) can be exemplified by acrylic-type resins, styrenic resins, epoxy-type resins, amide-type resins, amidoepoxy-type resins, alkyd-type resins, phenolic resins, and so forth. A single one of these may be used as component (A) or two or more may be used in combination as component (A). Among these, the presence of an acrylic-type polymer in component (A) is preferred from the standpoint of obtaining an excellent alkali developability and an excellent resist strippability after irradiation with light. This acrylic-type polymer more preferably contains as constituent units thereof both a monomer unit derived from acrylic acid and/or methacrylic acid and a monomer unit derived from alkyl acrylates and/or alkyl methacrylates. Here, "acrylic-type polymer" denotes a polymer that contains primarily monomer units derived from (meth)acrylic group-containing polymerizable monomer.
The aforementioned acrylic-type polymer may be produced, for example, by the radical polymerization of (meth)acrylic group-containing polymerizable monomer. This (meth)acrylic group-containing polymerizable monomer can be exemplified by acrylamide, acrylonitrile, alkyl (meth)acrylates, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, (meth)acrylic acid, .alpha.-bromo(meth)acrylic acid, .alpha.-chloro(meth)acrylic acid, .beta.-furyl(meth)acrylic acid, .beta.-styryl(meth)acrylic acid, and so forth. A single one of these may be employed as the polymerizable monomer or two or more may be used in combination as the polymerizable monomer. The alkyl (meth)acrylates cited above can be exemplified by methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and structural isomers of the preceding. A single one of these polymerizable monomers may be used or two or more can be used in combination.
In addition to the (meth)acrylic group-containing polymerizable monomer cited above, a single polymerizable monomer or two or more polymerizable monomers, as exemplified by styrene, polymerizable styrene derivatives e.g., vinyltoluene, .alpha.-methylstyrene, p-methylstyrene, p-ethylstyrene, and so forth, esters of vinyl alcohol such as vinyl n-butyl ether, maleic acid, maleic anhydride, maleate monoesters e.g., monomethyl maleate, monoethyl maleate, monoisopropyl maleate and so forth, fumaric acid, cinnamic acid, .alpha.-cyanocinnamic acid, itaconic acid, crotonic acid, propionic acid, and so forth, may also be copolymerized in the acrylic-type polymer.
The ethylenically unsaturated bond carried by component (B) is not particularly restricted as long as it is photopolymerizable and can be exemplified by .alpha.,.beta.-unsaturated carbonyl groups such as the (meth)acrylate group and so forth. Photopolymerizable compounds that have an .alpha.,.beta.-unsaturated carbonyl group as the ethylenically unsaturated bond can be exemplified by the .alpha.,.beta.-unsaturated carboxylic acid esters of polyvalent alcohols, (meth)acrylate compounds that contain the bisphenol A skeleton, adducts between glycidyl-functional compounds and .alpha.,.beta.-unsaturated carboxylic acids, urethane bond-containing (meth)acrylate compounds, nonylphenoxypolyethyleneoxyacrylates, (meth)acrylate compounds that contain the phthalic acid skeleton, alkyl (meth)acrylate esters, and so forth. A single one of these may be used or two or more of these may be used in combination. Viewed from the perspective of the adhesiveness and resistance to plating, preferred thereamong are (meth)acrylate compounds that contain the bisphenol A skeleton and urethane bond-containing (meth)acrylate compounds wherein (meth)acrylate compounds that contain the bisphenol A skeleton are particularly preferred.
The esters of polyvalent alcohols with .alpha.,.beta.-unsaturated carboxylic acids can be exemplified by polyethylene glycol di(meth)acrylates that have from 2 to 14 ethylene groups, polypropylene glycol di(meth)acrylates that have from 2 to 14 propylene groups, polyethylene.polypropylene glycol di(meth)acrylates that have from 2 to 14 ethylene groups and from 2 to 14 propylene groups, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO-+PO-modified trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and so forth. A single one of these may be used or two or more may be used in combination. With regard to the preceding compound names, "EO-modified" indicates a compound that has a block structure formed by the ethylene oxide group, while "PO-modified" indicates a compound that has a block structure formed by the propylene oxide group.
Among the preceding compounds, 2,2-bis(4-(methacryloxypentaethoxy)phenyl)propane can be acquired commercially as "BPE-500" (product name, Shin-nakamura Chemical Co., Ltd.). In addition, 2,2-bis(4-(methacryloxypentadecaethoxy)phenyl)propane can be acquired commercially as "BPE-1300" (product name, Shin-nakamura Chemical Co., Ltd.).
The urethane bond-containing (meth)acrylate compounds can be exemplified by the adducts of (meth)acrylic monomer having OH in the .beta.-position with a diisocyanate compound (e.g., isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate, and so forth), and by tris((meth)acryloxytetraethylene glycol isocyanate)hexamethylene isocyanurate, EO-modified urethane di(meth)acrylate, EO-+PO-modified urethane di(meth)acrylate, and so forth. "UA-11" (product name, Shin-nakamura Chemical Co., Ltd.) is an example of a commercially available EO-modified urethane di(meth)acrylate. "UA-13" (product name, Shin-nakamura Chemical Co., Ltd.) is an example of a commercially available EO-+PO-modified urethane di(meth)acrylate. A single one of these can be used or two or more can be used in combination.
The above-cited (meth)acrylate compound that contains the phthalic acid skeleton is not particularly limited as long as it contains the phthalic acid skeleton (the structure given by removing the hydrogen atoms from the two carboxyl groups of phthalic acid) and contains the methacrylate group or the acrylate group or both the methacrylate group and the acrylate group. Specific examples thereof are .gamma.-chloro-.alpha.-hydroxypropyl-.beta.'-(meth)acryloyloxyethyl-o-pht- halate, .beta.-hydroxyalkyl-.beta.'-(meth)acryloyloxyalkyl-o-phthalate, and so forth.
The pyrazoline derivative comprising component (C1) is represented by general formula (1), supra, but is not otherwise particularly limited. In formula (1), at least one R represents C.sub.1-10 alkoxy or C.sub.1-12 alkyl; the sum of a, b, and c is 1 to 6; and when the sum of a, b, and c is 2 to 6, each R may be the same as or different from one another.
The R's in component (C1) may be straight chain or may be branched. R can be exemplified by methoxy, isopropyl, n-butyl, tert-butyl, tert-octyl, and dodecyl, but is not limited to the preceding. The sum of a, b, and c in general formula (1) is preferably 1 to 6, more preferably 1 to 4, and particularly preferably 1 or 2.
From the perspective of bringing about additional improvements in the sensitivity and solubility, pyrazoline derivatives are preferred within the range available to component (C1) in which R is C.sub.1-10 alkoxy or C.sub.1-3 alkyl. Moreover, 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)-pyrazoline is particularly preferred from the perspective of ease of synthesis and bringing about an increased sensitivity, while 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)-pyrazoline is particularly preferred from the perspective of ease of synthesis and bringing about an additional increase in solubility.
The pyrazoline derivative (C1) can be exemplified by 1-(4-methoxyphenyl)-3-styryl-5-phenylpyrazoline, 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline, 1,5-bis-(4-methoxyphenyl)-3-(4-methoxystyryl)pyrazoline, 1-(4-isopropylphenyl)-3-styryl-5-phenylpyrazoline, 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)pyrazoline, 1,5-bis-(4-isopropylphenyl)-3-(4-isopropylstyryl)pyrazoline, 1-(4-methoxyphenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyrazoli- ne, 1-(4-tert-butylphenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoli- ne, 1-(4-isopropylphenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyr- azoline, 1-(4-tert-butylphenyl)-3-(4-isopropylstyryl)-5-(4-isopropylphenyl- )pyrazoline, 1-(4-methoxyphenyl)-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)pyrazoline- , 1-(4-isopropylphenyl)-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline, 1-phenyl-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)pyrazoline, 1-phenyl-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphenyl)pyrazoline, 1-phenyl-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)pyrazoline, 1-phenyl-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)pyrazoline, 1-phenyl-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)pyrazoline, 1-phenyl-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphenyl)pyrazoline, 1-(4-methoxyphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)pyrazo- line, 1-(4-methoxyphenyl)-3-(3,4-dimethoxystryl)-5-(3,4-dimethoxyphenyl)py- razoline, 1-(4-methoxyphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphen- yl)pyrazoline, 1-(4-methoxyphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphenyl)pyrazo- line, 1-(4-methoxyphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)p- yrazoline, 1-(4-methoxyphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphe- nyl)pyrazoline, 1-(4-tert-butylphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)pyr- azoline, 1-(4-tert-butylphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyph- enyl)pyrazoline, 1-(4-tert-butylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)pyr- azoline, 1-(4-tert-butylphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyph- enyl)pyrazoline, 1-(4-tert-butylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)pyr- azoline, 1-(4-tert-butylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyph- enyl)pyrazoline, 1-(4-isopropylphenyl)-3-(3,5-dimethoxystyryl)-5-(3,5-dimethoxyphenyl)pyra- zoline, 1-(4-isopropylphenyl)-3-(3,4-dimethoxystyryl)-5-(3,4-dimethoxyphen- yl)pyrazoline, 1-(4-isopropylphenyl)-3-(2,6-dimethoxystyryl)-5-(2,6-dimethoxyphenyl)pyra- zoline, 1-(4-isopropylphenyl)-3-(2,5-dimethoxystyryl)-5-(2,5-dimethoxyphen- yl)pyrazoline, 1-(4-isopropylphenyl)-3-(2,3-dimethoxystyryl)-5-(2,3-dimethoxyphenyl)pyra- zoline, 1-(4-isopropylphenyl)-3-(2,4-dimethoxystyryl)-5-(2,4-dimethoxyphen- yl)pyrazoline, 1-(4-tert-butylphenyl)-3-styryl-5-phenylpyrazoline, 1-phenyl-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyrazoline, 1,5-bis(4-tert-butylphenyl)-3-(4-tert-butylstyryl)pyrazoline, 1-(4-tert-octylphenyl)-3-styryl-5-phenylpyrazoline, 1-phenyl-3-(4-tert-octylstyryl)-5-(4-tert-octylphenyl)pyrazoline, 1,5-bis(4-tert-octylphenyl)-3-(4-tert-octylstyryl)pyrazoline, 1-(4-dodecylphenyl)-3-styryl-5-phenylpyrazoline, 1-phenyl-3-(4-dodecylstyryl)-5-(4-dodecylphenyl)pyrazoline, 1-(4-dodecylphenyl)-3-(4-dodecylstyryl)-5-(4-dodecylphenyl)pyrazoline, 1-(4-tert-octylphenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyraz- oline, 1-(4-tert-butylphenyl)-3-(4-tert-octylstyryl)-5-(4-tert-octylphenyl- )pyrazoline, 1-(4-dodecylphenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyrazoli- ne, 1-(4-tertbutylphenyl)-3-(4-dodecylstyryl)-5-(4-dodecylphenyl)pyrazolin- e, 1-(4-dodecylphenyl)-3-(4-tert-octylstyryl)-5-(4-tert-octylphenyl)pyrazo- line, 1-(4-tert-octylphenyl)-3-(4-dodecylstyryl)-5-(4-dodecylphenyl)pyrazo- line, 1-(2,4-di-n-butylphenyl)-3-(4-dodecylstyryl)-5-(4-dodecylphenyl)pyra- zoline, 1-phenyl-3-(3,5-di-tert-butylstyryl)-5-(3,5-di-tert-butylphenyl)py- razoline, 1-phenyl-3-(2,6-di-tert-butylstyryl)-5-(2,6-di-tert-butylphenyl)- pyrazoline, 1-phenyl-3-(2,5-di-tert-butylstyryl)-5-(2,5-di-tert-butylphenyl)pyrazolin- e, 1-phenyl-3-(2,6-di-n-butylstyryl)-5-(2,6-di-n-butylphenyl)pyrazoline, 1-(3,4-di-tert-butylphenyl)-3-styryl-5-phenylpyrazoline, 1-(3,5-di-tert-butylphenyl)-3-styryl-5-phenylpyrazoline, 1-(4-tert-butylphenyl)-3-(3,5-di-tert-butylstyryl)-5-(3,5-di-tert-butylph- enyl)pyrazoline, and 1-(3,5-di-tert-butylphenyl)-3-(3,5-di-tert-butylstyryl)-5-(3,5-di-tert-bu- tylphenyl)pyrazoline.
The pyrazoline derivative comprising the component (C1) of the present invention can be synthesized by known methods. For example, this pyrazoline derivative can be obtained by the synthetic method described in Japanese Granted Patent Number 2,931,693 or by synthetic methods based thereon. For example, a specific benzaldehyde can first be condensed by a known condensation method with acetone or a specific acetophenone compound in the presence of a base in a water-alcohol mixed solvent. Or, a specific benzaldehyde compound and a specific acetophenone compound can be condensed in an organic solvent in the presence of a base catalyst, for example, piperidine. The chalcone compound yielded by these condensations can then be condensed by a known method with a specific hydrazine compound, for example, by reaction in acetic acid or an alcohol, to obtain the pyrazoline derivative according to the present invention.
The following photopolymerization initiators may also be added to the photosensitive resin composition on an optional basis in addition to components (C1) and (C2): coumarin derivatives; benzophenone; N,N'-tetraalkyl-4,4'-diaminobenzophenones such as N,N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N,N'-tetraethyl-4,4'-diaminobenzophenone, and so forth; aromatic ketones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, and so forth; quinones such as alkylanthraquinones and so forth; benzoin ether compounds such as benzoin alkyl ethers and so forth; benzoin compounds such as benzoin, alkylbenzoins, and so forth; benzil derivatives such as benzil dimethyl ketone and so forth; acridine derivatives such as 9-phenylacridine, 1,7-bis(9,9'-acridino)heptane, and so forth; as well as N-phenylglycine, N-phenylglycine derivatives, and so forth.
Light sources that can be effectively used in the direct imaging technique described below can be exemplified by an argon gas laser emitting light at 364 nm, a solid UV laser emitting light at 355 nm, a gallium nitride-type blue laser emitting light at 405 nm, and so forth. The use of the gallium nitride-type blue laser is preferred thereamong from the perspective of being able to more easily form the resist pattern. In addition, a digital direct exposure instrument, for example, the "DE-1AH" (trade name) from Hitachi Via Mechanics, Ltd., may also be used.
The thickness of the photosensitive layer 14 is not particularly restricted, but is preferably approximately 1 to 100 .mu.m. In addition, a protective film may be coated on the photosensitive layer 14 on the side F1 opposite the support 10. This protective film can be exemplified by films of polyethylene, polypropylene, and so forth; preferably has an adhesive strength with the photosensitive layer 14 that is less than the adhesive strength between the support 10 and the photosensitive layer 14; and preferably is a low-fisheye film.
A film of, for example, polyethylene terephthalate, polypropylene, polyethylene, polyester, and so forth, can be suitably used as the support 10; its thickness is preferably 1 to 100 .mu.m.
The photosensitive element 1 can be obtained, for example, by coating the photosensitive resin composition on the support 10 and then drying to form the photosensitive layer 14. Coating can be carried out by known methods, for example, a roll coater, comma coater, gravure coater, air knife coater, die coater, bar coater, and so forth. Drying can be carried out at 70 to 150.degree. C. for about 5 to 30 minutes.
The above-described photosensitive element of the present embodiment can be suitably used in the photosensitive layer formation step. When the photosensitive element is employed, the protective film is removed (in those instances where the photosensitive element has a protective film) and the photosensitive layer, while being heated to about 70 to 130.degree. C., is then laminated under reduced or ambient pressure onto the substrate by press-bonding at a pressure of about 0.1 to 1 MPa (about 1 to 10 kgf/cm.sup.2) to form a photosensitive layer on the substrate. This substrate suitably takes the form of, for example, a copper-clad laminate comprising copper foil disposed on one or both surfaces of a layer comprising a dielectric material such as, for example, glass fiber-reinforced epoxy resin.
A direct imaging technique is suitably used in this embodiment from the standpoints of high sensitivity and high resolution. Light sources that can be used in the direct imaging technique can be exemplified by an argon gas laser emitting light at 364 nm, a solid UV laser emitting light at 355 nm, a gallium nitride-type blue laser emitting light at 405 nm, and so forth. The gallium nitride-type blue laser is suitably used thereamong from the perspective of being able to more easily form the resist pattern. In addition, a digital direct exposure instrument, for example, the "DE-1AH" (trade name) from Hitachi Via Mechanics, Ltd., may also be used.
The aqueous alkali solution used for development can be exemplified by 0.1 to 5 mass % aqueous sodium carbonate solutions, 0.1 to 5 mass % aqueous potassium carbonate solutions, 0.1 to 5 mass % aqueous sodium hydroxide solutions, and so forth. The pH of the aqueous alkali solution is preferably in the range from 9 to 11 and its temperature may be adjusted as appropriate in response to, for example, the solubility of the photosensitive layer. A surfactant, defoamer, organic solvent, and so forth may also be added to the aqueous alkali solution. The resin forming the resist pattern may as necessary be subjected to additional curing after the development step but prior to the formation of the conductor pattern; this additional curing may be effected by heating at about 60 to 250.degree. C. or by photoexposure to about 0.2 to 10 J/cm.sup.2.
Preparation of Photosensitive Resin Composition Solutions
The starting materials shown in Table 1, the component (C1) shown in Table 2 or 3, and the 4,4'-bis(diethylamino)benzophenone shown in Table 3 (abbreviated as EAB in Table 3) were intermixed to uniformity in the amounts shown in the respective tables to prepare solutions of photosensitive resin compositions according to Examples 1 to 7 and Comparative Examples 1 and 2. The following were used as component (C1): 1-phenyl-3-(4-methoxystyryl)-5-(4-methoxyphenyl)pyrazoline (abbreviated as PYR-M in Table 2), 1-phenyl-3-(4-isopropylstyryl)-5-(4-isopropylphenyl)pyrazoline (abbreviated as PYR-I in Table 2), and 1-phenyl-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)pyrazoline (abbreviated as PYR-B in Table 3).
A higher solubility in solvent is desirable for the PYR-M, PYR-I, and PYR-B from the standpoint of bringing about a better balance between the sensitivity and resolution. A high solubility also facilitates preparation of the photosensitive resin composition solution and thus provides an excellent workability. The solubility of PYR-M, PYR-I, and PYR-B in 100 mL toluene solvent at 23.degree. C. is shown in Table 4.
TABLE-US-00001 TABLE 1 Blending quantity Starting material (g) Component (A) 2-methoxyethanol/toluene solution 54 of methacrylic acid/methyl (solids) methacrylate/styrene (25/50/25 weight ratio, weight-average molecular weight: 55,000), acid number of the solids fraction: 163.1 mg KOH/g Component (B) EO-modified, bisphenol A skeleton 46 dimethacrylate Component (C2) 2,2'-bis(o-chlorophenyl)-4,5-4',5'- 3.7 tetraphenyl-1,2'-biimidazole Color former leuco crystal violet (LCV) 0.5 Dye malachite green (MKG) 0.03 Solvent acetone 10 toluene 7 N,N-dimethylformamide 3 methanol 3
TABLE-US-00002 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Component PYR-M 0.2 0.5 0.8 -- -- -- (C1) addition (g) PYR-I -- -- -- 0.2 0.5 0.8 addition (g) Thickness of the 25 25 25 25 25 25 photosensitive layer (.mu.m) OD value 365 nm 0.52 0.73 1.00 0.48 0.68 1.00 (absorbance) 405 nm 0.53 0.77 1.00 0.49 0.70 1.00 Sensitivity (mJ/cm.sup.2) 66 51 40 68 52 39 Resolution ST = 15 16 16 15 15 16 (.mu.m) 14/41 ST = 15 16 18 15 16 18 17/41 ST = 16 18 18 15 18 18 20/41
TABLE-US-00003 TABLE 3 Comp. Ex. 1 Comp. Ex. 2 Example 7 PYR-B addition (g) -- -- 0.2 EAB addition (g) -- 0.4 -- Thickness of the 25 25 25 photosensitive layer (.mu.m) OD value 365 nm 0.21 1.70 0.44 (absorbance) 405 nm 0.13 0.52 0.45 Sensitivity (mJ/cm.sup.2) 557 120 95 Resolution (.mu.m) ST = 14/41 16 20 15 ST = 17/41 18 18 16 ST = 20/41 20 20 20
TABLE-US-00004 TABLE 4 PYR-M PYR-I PYR-B Solubility (g) 3 20 5.2
The solutions prepared as described above of the photosensitive resin compositions of Examples 1 to 7 and Comparative Examples 1 and 2 were uniformly coated on 16 .mu.m-thick polyethylene terephthalate films. The coated solution (film coating) was then dried for 10 minutes at 70.degree. C. and 10 minutes at 100.degree. C. using a hot-wind convection drier to give a photosensitive element in which a photosensitive layer comprising the aforementioned photosensitive resin composition was disposed on one side of the polyethylene terephthalate film functioning as a support. The film thickness of the photosensitive layer was 25 .mu.m.
A two-sided copper-clad laminate (MCL-E-67 (product name) from Hitachi Chemical Co., Ltd.) was prepared; this two-sided copper-clad laminate had copper foil (thickness 35 .mu.m) laminated on both sides of a glass fiber-reinforced epoxy resin layer. The copper surface of this laminate was polished with a polisher (Sankei Co., Ltd.) fitted with a brush equivalent to #600 and was thereafter washed with water and dried in an air current. Then, while the two-sided copper-clad laminate was being heated to 80.degree. C., the photosensitive element obtained as described above was pasted thereon in such a manner that its photosensitive layer side was adhered to the copper foil surfaces; this was followed by pressing at 0.4 MPa while heating to 120.degree. C. Cooling to 23.degree. C. then yielded a laminate comprising the photosensitive layer disposed on both surfaces of the two-sided copper-clad laminate.
The following were then laid in the sequence given on the surface of the polyethylene terephthalate film that was disposed as the outermost layer of the laminate: a phototool provided with a 41-step tablet and, as a negative for evaluation of the resolution, a phototool provided with a wiring pattern that had line width/space width=6/6 to 35/35 (unit: .mu.m). The 41-step tablet on the phototool had a density range of 0.00 to 2.00 and a density step of 0.05; the tablet (rectangle) had a size of 20 mm.times.187 mm, and each step (rectangle) had a size of 3 mm.times.12 mm. An HG0405 (product name) spectral filter (bandpass filter that transmits light with a wavelength of 405 nm.+-.30 nm) from Asahi Spectra Co., Ltd., was then placed on top of this stack.
This assembly was exposed, using a parallel light exposure instrument having a 5 kW short arc lamp as its light source (product name: EXM-1201, from Orc Manufacturing Co., Ltd.), to light in an amount such that the number of remaining steps after development of the 41-step tablet was 14, 17, or 20. The sensitivity was defined as the amount of light exposure at which the number of remaining steps after development of the 41-step tablet was 17. The irradiance of the light transmitted through the bandpass filter was measured using an accumulating UV light meter and a detector, and the amount of light exposure was defined as irradiance.times.exposure time. A UIT-150-A (product name, from Ushio Inc., also usable as an irradiance meter) was used as the accumulating UV light meter and a UVD-S405 (product name, sensitivity wavelength region: 320 nm to 470 nm, wavelength for calibrating absolute value: 405 nm) was used as the detector.
The polyethylene terephthalate film was then removed and development was carried out by spraying the uncovered photosensitive layer for 24 seconds at 30.degree. C. with a 1.0 weight % aqueous sodium carbonate solution to remove those regions that had not been exposed to light. The resolution was defined as the smallest value of the line-to-line space width at which the regions not exposed to light could be cleanly removed, the lines did not meander, and void-free lines were produced. For the resolution and sensitivity as herein defined, smaller numerical values are indicative of better values.
Solutions of the photosensitive resin compositions according to Examples 8 to 13 and Comparative Example 3 were prepared by mixing the starting materials shown in Table 5, the component (C1) shown in Table 6, and leuco crystal violet to homogeneity using the amounts shown in the tables. 1-phenyl-3-(tert-butylstyryl)-5-(4-tert-butylphenyl)pyrazoline (PYR-B in Table 3, Nippon Chemical Industrial Co., Ltd.) was used as component (C1). The maximum absorption wavelength .lamda..sub.max of this pyrazoline derivative (wavelength of maximum absorbance) was 387.2 nm.
TABLE-US-00005 TABLE 5 Blending quantity Starting material (g) Component (A) 2-methoxyethanol/toluene solution 54 of methacrylic acid/methyl (solids) methacrylate/styrene (25/50/25 weight ratio, weight-average molecular weight: 55,000), acid number of the solids fraction: 163.1 mg KOH/g Component (B) EO-modified, bisphenol A skeleton 46 dimethacrylate Component (C2) 2,2'-bis(o-chlorophenyl)-4,5-4',5'- 3.7 tetraphenyl-1,2'-biimidazole Dye malachite green (MKG) 0.03 Solvent acetone 10 toluene 7 N,N-dimethylformamide 3 methanol 3
TABLE-US-00006 TABLE 6 Example Example Example Example Example Example Comp. 8 9 10 11 12 13 Example 3 Blending 0.30 0.50 0.70 0.25 0.25 0.25 -- quantity of component (C1) (g) Blending 0.30 0.30 0.30 0.30 0.50 1.0 0.30 quantity of leuco crystal violet addition (g) Thickness of 25 25 25 25 25 25 25 the photosensitive layer (.mu.m) OD 365 nm 0.673 0.998 1.229 1.202 0.504 0.515 0.063 value 405 nm 0.725 1.183 1.482 1.221 0.570 0.586 0.107 (absorbance) Sensitivity 94 71 63 83 83 75 557 (mJ/cm.sup.2) Resolution ST = 18 25 25 14 18 16 35 (.mu.m) 14/41 ST = 16 18 20 16 20 18 30 17/41 ST = 16 18 20 16 25 20 30 20/41
The solutions of the photosensitive resin compositions according to Examples 8 to 13 and Comparative Example 3 prepared as described above were uniformly coated on 16 .mu.m-thick polyethylene terephthalate film. The coated solution (coated film) was then dried for 10 minutes at 70.degree. C. and 10 minutes at 100.degree. C. using a hot-wind convection drier to give a photosensitive element in which a photosensitive layer comprising the photosensitive resin composition was disposed on one side of the polyethylene terephthalate film functioning as a support. The film thickness of the photosensitive layer was 25 .mu.m.
Proceeding as in Examples 1 to 7 and Comparative Examples 1 and 2, a laminate in which the photosensitive layer was disposed on both sides of the two-sided copper-clad laminate was first obtained. Then, again proceeding as in Examples 1 to 7 and Comparative Examples 1 and 2, the following were laid in the sequence given on the surface of the polyethylene terephthalate film that was disposed as the outermost layer of the laminate: a phototool provided with a 41-step tablet and a phototool provided with a prescribed wiring pattern. An HG0405 (product name) spectral filter (bandpass filter that transmits light with a wavelength of 405 nm.+-.30 nm) from Asahi Spectra Co., Ltd., was then placed on top of this stack.
This assembly was exposed to light as in Examples 1 to 7 and Comparative Examples 1 and 2. The sensitivity was defined as the amount of light exposure at which the number of remaining steps after development of the 41-step tablet was 17. The irradiance of the light transmitted through the bandpass filter was measured as before using an accumulating UV light meter and a detector, and the amount of light exposure was defined as irradiance.times.exposure time.
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