JP4159056B2 - Aqueous developable photosensitive resistor composition for photolithography and method for forming thick film resistor - Google Patents

Description

【００４９】
Ｂ. ペースト調製
ペーストの調製は黄色灯の下で行った。最初に有機成分を調合後に予備混合し、次に予備混合した有機成分に無機成分を加えて混合した後、ロールミルを用いて混練した。
【００５０】
Ｃ. 処理条件
汚染は欠陥の原因になり得るので、コーティング組成物の製造工程においてそして製品の製造においてごみによる汚染を避けるべく注意を払った。工程の作業はクラス−１００のクリーンルームで行なった。
ペーストを１００〜４００メッシュスクリーンを用いるスクリーン印刷によりセラミック製品に塗布した。製品を窒素または空気の雰囲気のオーブン中において７０〜１００℃で乾燥した。乾燥したコーティングの厚さは８〜２０μｍであった。
【００５１】
製品を紫外線露光装置を用い、１kWの水銀灯に露光した。最適の露光時間は現像後の正確な寸法のラインを得るに必要な最小の露光の情報を許容する露光シリーズから決定した。
露光した製品は０.８５重量％の炭酸ナトリウム水溶液（２０〜４５℃）でデュポン社製Ｃ１１プロセッサーを用いて現像した。現像液は１０〜２５Psiで噴霧し、現像速度は３〜１５フィート／分であった。
現像後、乾燥した製品を空気炉中において最高温度６０５℃、４０分サイクルで焼成した。
【００５２】
３） 評価試験
Ａ． 評価試料
表１に示す成分を用いて上記のようにして、実施例１〜５の試料を調製した。
【００５３】
【表１】

【００５４】
実施例１〜５に使用したガラス結合剤は、表２に示す化合物から、通常の製造方法で製造することができる。
【００５５】
【表２】

【００５６】
Ｂ． 比較試料
導電性成分としてパイロクロアＩ １０.００％およびルテニウム酸化物 ５％、無機結合剤としてガラスフリットＩ ３０％およびガラスフリットII ２５％、そしてビヒクル３０％を含有する従来の厚膜抵抗体組成物を比較試料とした。
ここにビヒクルはエチルセルロース１０〜３０重量部とβ−テルピネオール９０〜７０重量部ならびに分散剤１０重量部以下の混合物である。
【００５７】
Ｃ． 評価試験
表１に示す実施試料１〜５および比較試料の組成物を基板に印刷し、得られたパターンを乾燥および焼成して、シート抵抗値（Ω／□）、平均乾燥および焼成膜厚および解像度を測定した。ここに解像度は各ラインの一方が放射線上にひろがり、各ラインの他方が中心に向かって収斂するいわゆる扇状のパターンにおいて、幅の小さくなって行く方向にマイクロスコープで細くなった抵抗体ラインがどこまで切れずに形成されているかを観察し、ラインが切れている直前の抵抗体ライン幅を測定し（mil）単位で表わした。
評価結果を表３に示す。
【００５８】
【表３】

【００５９】
【発明の効果】
本発明の感光性抵抗体組成物は上述のごとく構成したので、これを用いて基板に印刷後乾燥し、露光、現像した後、再度乾燥し、焼成することによって良好な電気特性を保持しながらファインパターンの形成された厚膜抵抗体を得ることができる。
【００６０】
本発明の厚膜抵抗体は如何なる形状にも、また従来の組成物およびスクリーン印刷を用いて可能であるよりも小さい寸法にもパターン化できる。本発明のパターン化抵抗体により、正確な抵抗体幾何学およびレーザートリミングの排除もまた実現する。これらの特性は、正確な配置にかつよく制御された厚さで基板の広い領域に抵抗体をパターン化することを容易にする。さらに、複合回路製品の構成要素の一つとして抵抗体を形成する場合でさえ、抵抗体の他の要素に対する位置関係は、本発明の抵抗体を多機能部品中のスクリーン印刷されるコンデンサーおよび誘導子との組み合わせに用いることができるように、正確に選択できる。[0001]
[Industrial application fields]
The present invention relates to a photosensitive resistor composition for forming a resistor having high resolution and good dimensional accuracy on an insulating substrate using photolithography technology and thick film technology.
[0002]
[Prior art]
Conventionally, thick film resistor compositions widely used in thick film resistive electronic components and thick film hybrid circuit components are printed on a conductor pattern or electrode formed on an insulating substrate and then fired. A thick film resistor is formed.
[0003]
The thick film resistor composition is prepared by dispersing a conductive component and an inorganic binder in an organic medium (vehicle). The conductive component mainly has the role of determining the electrical properties of the thick film resistor, and ruthenium oxide or the like is used. The inorganic binder is made of glass and mainly has a role of holding the thick film integrally and bonding it to the substrate. An organic medium is a dispersion medium that affects the application properties of the composition, in particular its rheology.
[0004]
Such thick film resistor compositions are generally applied by screen printing with a desired pattern for the thick film resistor. However, when these thick film resistor compositions are applied in a pattern by screen printing, it is difficult to obtain fine line and spacing resolution. Circuit technology is rapidly progressing towards miniaturization and increasing the density of hybrid microelectronic circuits and surface mount components. Small high-density circuits and components such as resistors and capacitors are combined and integrated with maximum efficiency. Application of thick film technology is desired for the emergence of circuit devices. Application of thick film technology is also desired for display technology in which individual display elements are miniaturized.
[0005]
On the other hand, studies have been conducted to form a multilayer thick film circuit using a photopolymerizable paste composition. In this method, a conductive material and / or an inorganic binder is dispersed in a photosensitive medium to form a photosensitive conductive and / or dielectric paste composition. Next, a photosensitive paste composition is applied to the substrate, and the position of the image is exposed to actinic rays. After the exposure, the photosensitive paste is solvent-developed to remove the unexposed arcus with actinic rays to form a desired pattern layer. Further, the pattern layer is fired to burn off organic substances and sinter the inorganic solid.
[0006]
In order to satisfy the requirements of fine patterns in the formation of electronic circuits containing at least single resistors or composites in recent years, and to obtain controlled conductivity and high dimensional stability at the same time, inorganic solids and photopolymerizable organic media (vehicles) It is desired to integrate a thick film resistor in the formation of an electronic circuit.
[0007]
[Problems to be solved by the invention]
The present invention comprises a finely divided inorganic particulate material, an unsaturated monomer, a polymer binder and a sensitizer dispersion, and can form a fine pattern of a resistor thick film while maintaining good electrical properties, And it aims at providing the photosensitive resistor composition which can achieve the pattern resolution and resolution exceeding the limit of the printing precision of screen printing.
[0008]
[Means for Solving the Problems]
  The present invention
  (a) LeAt least one fine particle of a tenium oxide and a ruthenium-based pyrochlore oxide17 . 56weight%,and
  (b) Fine particles of an inorganic binder having a glass transition temperature of 350 ° C. to 825 ° C. and a particle size of 0.1 to 10 μm39 . 3~ 75 weight%
OrInorganic solid content44 . 3~ 80% by weight, and
  (d) an organic polymer binder,
  (e) a photoinitiator,
  (f) a photocurable monomer and
  (g) Organic medium
Organic vehicle consisting of55 . 7~ 20% by weight
KaraFor aqueous developable photolithographyIt is a photosensitive resistor composition.
[0009]
The present invention also provides a method for forming a thick film resistor comprising: coating the photosensitive resistor composition on an insulating substrate; exposing the composition; and baking after development at a temperature of 500 ° C. to 1,000 ° C. is there.
[0010]
A. Conductive component
The thick film resistor composition of the present invention contains a noble metal, ruthenium oxide or ruthenium-based pyrochlore oxide as a conductive component. Examples of noble metals include gold, silver, platinum, palladium and the like. Ruthenium-based pyrochlore oxide is a Ru represented by the following general formula:⁺⁴, Ir⁺⁴Or it is 1 type of the pyrochlore oxide which is a multicomponent compound of the mixture (M ").
(M_xBi_2-x) (M '_y M ″_2-y) O_7-z
Wherein M is selected from the group consisting of yttrium, thallium, indium, cadmium, lead, copper and rare earth metals;
M ′ is selected from the group consisting of platinum, titanium, chromium, rhodium and antimony;
M ″ is ruthenium, iridium or a mixture thereof;
x is 0 to 2, provided that x ≦ 1 for monovalent copper,
y is 0 to 0.5, provided that Y is 0 to 1 if M 'is rhodium or more than one of platinum, titanium, chromium, rhodium and antimony, and
z is from 0 to 1 except that when M is divalent lead or cadmium, this is at least equal to about x / 2.
These ruthenium-based pyrochlore oxides are described in detail in US Pat. No. 3,583,931.
[0011]
Among the ruthenium-based pyrochlore oxides, preferred is bismuth ruthenate Bi.₂Ru₂O₇And lead ruthenate Pb₂Ru₂O₆It is. They are easily obtained in pure form, are not adversely affected by the glass binder, have a relatively small TCR (temperature coefficient of resistance), and are stable even when heated to about 1000 ° C. in air. Yes, and relatively stable even in a reducing atmosphere. More preferred is lead ruthenate Pb₂Ru₂O₆It is. In addition, Pb_1.5Bi_0.5Ru₂O_6.25And CdBiRu₂O_6.5Pyrochlore can also be used. For all these, y = 0.
[0012]
Ruthenium oxide and / or ruthenium-based pyrochlore oxide is used in a proportion of 5 to 50% by weight, preferably 6 to 42% by weight, based on the total weight of the composition containing the organic medium. Based on the total amount of inorganic solids, it is 14 to 75% by weight, preferably 17 to 57% by weight. The total inorganic solid content refers to the total of the conductive component and the inorganic binder. When the composition of the present invention contains a metal oxide and / or fluoride additive in addition to the conductive component and the inorganic binder, the total inorganic solid content includes the additive.
[0013]
B. Inorganic binder
The glass frit used in the present invention assists sintering of the conductive component particles, and may be any well-known composition having a softening point below the melting point of the conductive component. In order to obtain sufficient conductivity of the device, it is desirable that the glass transition temperature [Tg] of the inorganic binder is 350 to 825 ° C, more preferably 350 to 750 ° C.
20m inorganic binder²Should have a specific surface area of less than / g. It is preferable that an average particle diameter is 0.5-10 micrometers.
The inorganic binder is preferably 5 to 75% by weight of the total composition. When the amount of the inorganic binder is further increased, the binding property to the substrate is lowered.
[0014]
C. Metal oxide and / or fluoride additives
The thick film resistor composition of the present invention may contain up to 30% by weight of metal oxide and / or fluoride as an additive. This metal oxide and / or fluoride serves to change the characteristics of the resistor, mainly
-Move the TCR
-Change the sintering state
-Change the coefficient of thermal expansion (TCE)
-Change firing surface condition
Depending on the purpose, a metal oxide and / or fluoride having an average particle diameter of 0.01 to 10 μm can be added.
[0015]
D. Organic polymer binder
The polymeric binder is important for the composition of the present invention. It must take into account the aqueous processability and give high resolution. These requirements have been found to be met by selecting the following binders: That is, this binder is (1) C₁~ C_TenAlkyl acrylate, C₁~ C_TenA non-acidic comonomer comprising an alkyl methacrylate, styrene, substituted styrene or combinations thereof and (2) a copolymer or interpolymer comprising an acidic comonomer comprising an ethylenically unsaturated carboxylic acid occupying at least 15% by weight of the total polymer weight. is there.
[0016]
The presence of the acidic comonomer component of the composition is important to the technology. The acid functionality results in developability in an aqueous base such as 0.8% aqueous sodium carbonate. When the acidic comonomer is present at a concentration of 15% by weight or less, the composition is not washed away with an aqueous base. When the acidic comonomer is present at a concentration of 30% by weight or more, the development conditions become unstable and partial development occurs in the image area. Suitable acidic comonomers are ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid and ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, citraconic acid, vinyl succinic acid and maleic acid and their half. Esters, optionally their anhydrides and mixtures thereof. Methacrylic polymers are preferred over acrylic polymers because they burn more cleanly in a low oxygen atmosphere.
[0017]
As noted above, when the non-acidic comonomer is an alkyl acrylate or alkyl methacrylate, these non-acidic comonomers preferably constitute at least 50% by weight of the polymer binder, preferably 70-75% by weight. When the non-acidic comonomer is styrene or substituted styrene, these non-acidic comonomers constitute 50% by weight of the polymer binder, while the other 50% by weight is an acid anhydride, for example a half ester of maleic anhydride. Is preferred. A preferred substituted styrene is α-methylstyrene.
[0018]
Although not preferred, the non-acidic portion of the polymeric binder can contain up to about 50% by weight of other non-acidic comonomers as an alternative to the alkyl acrylate, alkyl methacrylate, styrene, or substituted styrene portions of the polymer. Examples thereof include acrylonitrile, vinyl acetate, acrylamide and the like as long as the composition criteria discussed above and the following physical criteria are met. However, since their complete combustion is more difficult, such monomers are preferably used at less than about 25% by weight in the total polymer binder.
[0019]
The use of a single copolymer or a combination of copolymers as a binder will be appreciated if each of them meets the above criteria. In addition to the above copolymers, it is possible to add small amounts of other polymer binders. Examples of these include polyolefins such as polyethylene, polypropylene, polybutylene, polyisobutylene and ethylene-propylene copolymers; and polyethers which are polymers of low alkylene oxides such as polyethylene oxide.
The polymer can be made by conventional techniques of acrylate polymerization by conventional solution polymerization techniques.
[0020]
Typically, such acidic acrylate polymers have a relatively low boiling point (75-150) with one or more vinyl monomers (non-acidic comonomers) copolymerizable with α- or β-ethylenically unsaturated acids (acidic comonomers). C.) in an organic solvent to obtain a 10-60% solution of the monomer mixture, then the monomer is polymerized by addition of a polymerization catalyst, and the mixture is heated to the reflux temperature of the solution under normal pressure. After the polymerization reaction is substantially completed, the resulting acidic polymer solution is cooled to room temperature, a sample is taken, and the viscosity, molecular weight, acid equivalent, etc. of the polymer are measured.
[0021]
Furthermore, it is necessary to keep the molecular weight of the acid-containing binder polymer at 50,000 or less, preferably 25,000 or less, more preferably 15,000 or less.
If the composition is applied by screen printing, the binder polymer preferably has a Tg (glass transition temperature) of 90 ° C or higher.
After screen printing, the paste is usually dried at a temperature of up to 90 ° C. A Tg having a temperature below this temperature is generally a very sticky composition. Even lower Tg values can be employed for materials applied by methods other than screen printing.
The organic polymer binder is generally present in an amount of 5 to 45% by weight, based on the total weight of the dry photopolymerizable layer.
[0022]
E. Photoinitiator system
Suitable photoinitiator systems are those that are thermally inert but generate free radicals when exposed to actinic radiation at temperatures of 85 ° C. or lower. These are substituted or unsubstituted polynuclear quinones which are compounds having two intramolecular rings in a conjugated carbocyclic system, such as 9,10-anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2- Tertiary butylanthraquinone, octamethylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrenequinone, benz (za) anthracene-7,12-dione, 2,3-naphthacene-5,12-dione, 2- Methyl-1,4-naphthoquinone, 1,4-dimethyl-anthraquinone, 2,3-dimethylanthraquine, 2-phenylanthraquine, 2,3-diphenylanthraquine, retenquinone, 7,8,9,10-tetrahydronaphtha Sen-5,12-dione and 1,2,3,4-tetrahydrobenz (the) anthracene-7,12-dione It encompasses. Other photoinitiators that are also useful are described in US Pat. No. 2,760,863, even though some are thermally active at temperatures as low as 85 ° C., and are adjacent (vicinal) ketals. Donyl alcohols such as benzoin, bivalloin, acyloin ethers such as benzoin methyl and ethyl ether; α-hydrocarbon-substituted aromatic acyloins, including α-methylbenzoin, α-allylbenzoin and α-phenylbenzoin .
[0023]
US Pat. Nos. 2,850,445, 2,875,047, 3,097,096, 3,074,974, 3,097,097 and photoreducing dyes and reducing agents Phenatin, oxatin and Michler's ketone as disclosed in US Pat. No. 3,145,104 and US Pat. Nos. 3,427,161, 3,479,185 and 3,549,367 2,4,5-Triphenylimidazolyl dimers with hydrogen donors, including quinones, ethyl Michler's ketones, benzophenones, leuco dyes, and mixtures thereof can be used as initiators. In addition, the sensitizer disclosed in US Pat. No. 4,162,162 is useful in combination with a photoinitiator and a photopolymerization inhibitor.
[0024]
F. Photocurable monomer
The photocurable monomer component of the present invention is composed of at least one addition polymerizable ethylenically unsaturated compound having at least one polymerizable ethylene group.
Such compounds are those that can be initiated by free radicals and chain-growth addition polymerized to form polymers. The monomer compound has a boiling point of 100 ° C. or higher, that is, non-gas, and has a plasticizing action of an organic polymerizable binder.
[0025]
Suitable monomers that can be used alone or in combination with other monomers include t-butyl acrylate and methacrylate, 1,5-pentanediol diacrylate and dimethacrylate, N, N-dimethylaminoethyl acrylate and methacrylate. Ethylene glycol diacrylate and dimethacrylate, 1,4-butanediol diacrylate and dimethacrylate, diethylene glycol diacrylate and dimethacrylate, hexamethylene glycol diacrylate and dimethacrylate, 1,3-propanediol diacrylate and dimethacrylate, deca Methylene glycol diacrylate and dimethacrylate, 1,4-cyclohexanediol diacrylate and dimethacrylate 2,2-dimethylolpropane diacrylate and dimethacrylate, glycerol diacrylate and dimethacrylate, tripropylene glycol diacrylate and dimethacrylate, glycerol triacrylate and trimethacrylate, trimethylolpropane triacrylate and trimethacrylate, pentaerythritol triacrylate and Trimethacrylate, polyoxyethylated trimethylolpropane triacrylate and trimethacrylate and compounds similar to those disclosed in US Pat. No. 3,380,381, 2,2-di (p-hydroxyphenyl) -propanediacrylate , Pentaerythritol tetraacrylate and tetramethacrylate, 2,2-di- (p-hydroxyphenyl)- Lopandiacrylate, pentaerythritol tetraacrylate and tetramethacrylate, 2,2-di (p-hydroxyphenyl) -propanedimethacrylate, triethylene glycol diacrylate, polyoxyethyl-1,2-di- (p-hydroxyphenyl) Propane dimethacrylate, di- (3-methacryloxy-2-hydroxypropyl) ether of bisphenol-A, di- (3-acryloxy-2-hydroxypropyl) ether of bisphenol-A, di- (2-methacrylic acid) of bisphenol-A Roxyethyl) ether, di (3-acryloxy-2-hydroxypropyl) ether of bisphenol-A, di- (2-acryloxyethyl) ether of bisphenol-A, di- (3-methacrylate of 1,4-butanediol Roxy-2-hydroxypropyl) ether, triethylene glycol dimethacrylate, polyoxypropyltrimethylolpropane triacrylate, butylene glycol diacrylate and dimethacrylate, 1,2,4-butanetriol triacrylate and trimethacrylate, 2,2, 4-trimethyl-1,3-pentanediol diacrylate and dimethacrylate, 1-phenylethylene-1,2-dimethacrylate, diallyl fumarate, styrene, 1,4-benzenediol dimethacrylate, 1,4-diisopropenyl Benzene and 1,3,5-triisopropenylbenzene are included.
[0026]
Ethylenically unsaturated compounds having a molecular weight of at least 300, for example alkylene or polyalkylene glycol diacrylates made from alkylene glycols or polyalkylene glycols having 1 to 10 ether bonds of alkylene glycols having 2 to 15 carbon atoms and US patents Also useful are those having a plurality of addition polymerizable ethylene linkages disclosed in US Pat. No. 2,927,022, such as those present as terminal linkages in particular.
[0027]
Preferred monomers are polyoxyethylated trimethylolpropane triacrylate and methacrylate, ethylated pentaerythritol triacrylate, trimethylolpropane triacrylate and methacrylate, dipentaerythritol monohydroxypentaacrylate and 1,10-decanediol dimethylacrylate.
[0028]
Other preferred monomers are monohydroxy polycaprolactone monoacrylate, polyethylene glycol diacrylate (molecular weight, about 200), and polyethylene glycol 400 dimethacrylate (molecular weight, about 400). The unsaturated monomer component is present in an amount of 1 to 20% by weight, based on the total weight of the dry photopolymerizable layer.
[0029]
G. Dispersant
A dispersant can be added to ensure effective wetting of the inorganic material by the organic polymer and monomer. A fully dispersed inorganic binder is desirable for the preparation of a photoactive sheet having good flexibility, untreated base strength, and properties necessary for complete combustion of organics during firing. The dispersant acts such that the polymer binder wets the inorganic solids to give a system free of aggregates.
[0030]
H. Thermal polymerization inhibitor
It is generally desirable to add an inhibitor to prevent thermal polymerization during drying and storage. However, it is not essential for the photopolymerizable composition. Examples of thermal polymerization inhibitors that can be used in the photopolymerizable composition include p-methoxyphenol, hydroquinone, alkyl- and aryl-substituted hydroquinones, quinones, tert-butyl-catechol, pyrogallol, copper acid resin, and naphthylamines. , Β-naphthol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, phenothiazine, pyridine, nitrobenzene, dinitrobenzene, p-tolylquinone and chloranil. Nitroso compositions disclosed in US Pat. No. 4,168,982 are also useful as thermal polymerization inhibitors.
[0031]
I. Stabilizer
When multivalent metal cations are present in the resistor composition, it is preferable to add a stabilizer. Without the addition of a stabilizer, the polyvalent cation reacts with the acid functional group in the polymer binder to ionically crosslink the polymer chain and increase the viscosity of the resistor composition. Any compound that prevents such crosslinking but does not adversely affect other properties of the photosensitive resistor composition can be added to the dispersing composition. These stabilizers form a complex with the polyvalent cation and inhibit the reaction with the acid functional group in the polymer binder. Although the mechanism is not clearly understood, it has been found that triazole compounds function well as stabilizers in the compositions of the present invention. Benzotriazole and / or its carboxylic acid derivative, 1H-benzotriazole carboxylic acid is particularly preferred. Carboxylic acids contained in anionic surfactants and other molecules are also effective in preventing a decrease in viscosity or an increase in viscosity.
[0032]
J. Organic media
The main purpose of the organic medium is to act as a vehicle for a fine solid dispersion of the composition, in a form that can be easily applied to a ceramic or other substrate. Therefore, firstly, the organic medium must be capable of dispersing solids with sufficient stability. Secondly, the rheological properties of the organic medium must be such that it provides good applicability to the dispersion.
[0033]
When formulating the composition of the present invention as a thick film composition, it is usually applied to a substrate by screen printing. In this case, the composition is applied as a smooth continuous layer rather than a pattern. Therefore, the composition must have a suitable viscosity so that it can easily pass through the screen. Rheological properties are extremely important. It is preferred to formulate the organic medium to provide adequate wettability of the solid and substrate, good drying rate, sufficient dry film strength to withstand rough handling and good flammability. The satisfactory appearance of the fired composition is also important.
[0034]
In all aspects of these criteria, a wide range of inert liquids can be used as the organic medium. The organic medium for many thick film compositions is typically a solvent solution of organic components (binder, monomer, photoinitiator, etc.) in a solvent. The solvent usually boils in the range of 130-350 ° C.
[0035]
The most widely used solvents for thick film coating are terpenes such as α- or β-terpineol, kerosene, dibutyl phthalate, carbitol acetate, butyl carbitol acetate, hexamethylene glycol-2,2,4-trimethyl-1, 3-pentanediol monobutyrate and high boiling alcohols and alcohol esters or mixtures thereof. Various combinations of these and other solvents are formulated to obtain the desired viscosity and volatility for each application.
The final composition may be thixotropic or have Newtonian properties depending on the additive introduced into the composition.
[0036]
The ratio of organic medium to inorganic solid in the dispersion varies considerably and depends on the method of applying the dispersion and the type of organic medium used. Usually, to obtain good coverage, the dispersion contains 50-90% by weight solids and 50-10% by weight organic medium. Such dispersions are usually semi-fluid and are commonly referred to as “pastes”. The paste is conveniently prepared on a three roll mill. The viscosity of the paste is typically in the range of 25-200 P.S. The amount and type of organic medium used is largely determined by the viscosity and print thickness of the final desired formulation.
[0037]
As long as the photopolymerizable composition retains its essential properties, the organic medium can contain small amounts of other components such as pigments, dyes, thermal polymerization inhibitors, adhesion promoters such as organosilane coupling agents, plasticizers, coating aids. An agent such as polyethylene oxide may be contained. Organosilanes are particularly useful in amounts of 3.0% by weight or less based on the weight of the inorganic particles. The treated particles further reduce the amount of organic matter. Therefore, the amount of organic matter in the coating can be reduced, and as a result, combustion during firing is further facilitated.
[0038]
When the dispersion is formed into a film, the organic medium in which the fine particles of the conductive component and the inorganic binder are dispersed is a polymer binder, monomer and initiator dissolved in a volatile organic solvent, and optionally other dissolved substances such as plastics. It consists of an agent, a release agent, a dispersant, a release agent, an antifouling agent and a wetting agent.
[0039]
The solvent component of the organic medium may be a mixture of solvents, and polymers and other having a sufficiently high volatility such that the solvent evaporates from the dispersion by applying a relatively low level of heat at atmospheric pressure. A complete solution of the organic components may be obtained and selected. Furthermore, the solvent must boil well below the boiling point and decomposition temperature of any other additive contained in the organic medium. Therefore, a solvent having an atmospheric boiling point of 150 ° C. or less is most often used. Such solvents include benzene, acetone, xylene, methanol, ethanol, methyl ethyl ketone, amyl acetate, 2,2,4-triethylpentanediol-1,3-mono-isobutyrate, toluene and ethylene glycol monoalkyl and dialkyl ethers such as ethylene glycol. Mono-n-propyl ether is included.
[0040]
In many cases, the organic medium may also contain one or more plasticizers that affect the Tg reduction of the binder polymer. Such plasticizers ensure a good coating on the ceramic substrate and work to improve the developability of the unexposed parts of the composition. However, the use of such materials should be minimized as it increases the amount of organic material that must be removed when firing the film formed therefrom. Of course, the choice of plasticizer is largely determined by the polymer to be modified. Among the plasticizers used in various binder systems are diethyl phthalate, dibutyl phthalate, butyl benzyl phthalate, dibenzyl phthalate, alkyl phosphate, polyalkylene glycol, glycerol poly (ethylene oxide), hydroxyethylated alkylphenol, tricresyl There are phosphates, triethylene glycol diacetate and polyester plasticizers. Dibutyl phthalate is frequently used in acrylic polymer systems because it can be used effectively at relatively low concentrations.
[0041]
The photopolymerizable composition is applied to the support film at a dry coating thickness of from about 0.0005 inch (0.0032 cm) to about 0.001 inch (0.025 cm) or more. Suitable releasable supports, preferably having high dimensional stability against temperature changes, may be selected from a wide range of films composed of, for example, polyamides, polyolefins, polyesters, vinyl polymers and cellulose esters, and 0. It may have a thickness of 005 inches (0.012 cm) to 0.008 inches (0.02 cm) or more. If exposed prior to removal of the peelable support, of course it must transmit a substantial portion of the incident actinic light. If the peelable support is removed before exposure, this limitation does not apply. A particularly suitable support is a clear polyethylene terephthalate film having a thickness of about 0.0001 inch (0.0025 cm).
[0042]
When trying to store in roll form without a removable protective cover sheet, apply a thin release layer of a material such as wax or silicone on the opposite side of the peelable support to avoid sticking of the photopolymerizable material It is preferable. In other cases, adhesion to the coated photopolymerizable layer may be preferentially increased by flame treatment or electrical discharge machining treatment of the support surface to be coated.
[0043]
A removable protective cover sheet suitable for use may be selected from the same group of high polymer films as described above and may have the same wide range of thicknesses. A polyethylene cover sheet having a thickness of 0.0001 inches is particularly suitable. The above support and cover sheet favorably protect the photopolymerizable layer during storage before use.
[0044]
Processing
The photosensitive resistor composition is generally applied to the substrate in the form of a film or to the substrate in the form of a paste, for example by screen printing. The resistive composition is then image exposed to actinic light to determine the exposed portion. Aqueous development to remove unexposed portions of the layer. The exposed portion is substantially unaffected by the use of a developer such as a complete aqueous solution containing 0.8% by weight sodium carbonate. In the present invention, it is understood that it is not necessary to perform development using a 0.8 wt% sodium carbonate solution in actual use, and other alkaline aqueous solutions may be used, for example. However, the compositions of the present invention have developability in such carbonate solutions. Usually, development is performed within 0.25 to 2 minutes.
[0045]
The other processing steps involved may be conventional and can be performed before the firing operation is performed. Firing is performed to volatilize the organic component and to sinter the inorganic binder and the conductive component. Firing is performed in an oxidizing atmosphere or a substantially non-oxidizing atmosphere. A preferred oxidizing atmosphere is air. By “substantially non-oxidizing atmosphere” is meant an atmosphere containing sufficient oxygen to completely burn organic materials. As an example of a “substantially non-oxidizing atmosphere”, 10 to 200 ppm O₂A nitrogen atmosphere has been found. An additional example is a nitrogen atmosphere containing several volume percent of water vapor that assists in the combustion of organic matter.
[0046]
【Example】
In the following examples, the following component materials having the indicated properties were used. Unless otherwise noted, all concentrations are in parts by weight and temperatures are in ° C.
1) Component materials
A. Inorganic matter
Glass frit I, II: Shown in Table 2 below.
Pyrochlore I, II, ruthenium oxide I, II: shown in Table 1 below.
B. Polymer binder
Binder: Copolymer of 75% methyl methacrylate and 25% methacrylic acid (molecular weight 7000, Tg-110 ° C., acid number 160)
C. Monomer
Monomer I: TEOTA 1000-polyoxyethylated trimethylolpropane triacrylate (molecular weight 1,162)
Monomer II: TMPTA-trimethylolpropane triacrylate
D. Solvent
2,2,4-trimethyl-1,3-pentanediol monoisobutyrate
E. Initiator
Photoinitiator 1: 2,2-dimethoxy-1,2-diphenylethane-1-one
〃 2: Isopropylthioxanthone
３ 3: Ethyl-p-dimethylaminobenzoate
F. Stabilizer
1H-benzotriazole carboxylic acid
G. Dispersant
Gafac 610 (Riverside Chemical Inc.)-Complex organophosphate
H. Thermal polymerization inhibitor
1,4,4-trimethyl-2,3-diazabicyclo [3.2.2] -non-2-one-N, N'-dioxide
[0047]
2) Manufacture of photosensitive paste that can be processed in water
A. Manufacture of organic vehicles
The organic component, solvent and acrylic polymer were mixed. Heat to 120 ° C. with stirring and continue heating and stirring until all the binder polymer is dissolved. The solution was then cooled to 90 ° C. and initiator and stabilizer were added. This mixture was then stirred at 90 ° C. to dissolve the solids, after which the solution was passed through a 400 mesh filter and cooled.
[0048]
The vehicle used has the following composition:

[0049]
B. Paste preparation
The paste was prepared under a yellow light. First, the organic components were premixed after blending, then the inorganic components were added to the premixed organic components and mixed, and then kneaded using a roll mill.
[0050]
C. Processing conditions
Care has been taken to avoid contamination by dirt in the manufacturing process of the coating composition and in the manufacture of the product, as contamination can cause defects. The process work was performed in a class-100 clean room.
The paste was applied to the ceramic product by screen printing using a 100-400 mesh screen. The product was dried at 70-100 ° C. in an oven with a nitrogen or air atmosphere. The dried coating thickness was 8-20 μm.
[0051]
The product was exposed to a 1 kW mercury lamp using an ultraviolet exposure device. The optimal exposure time was determined from an exposure series that allowed the minimum exposure information necessary to obtain a line of accurate dimensions after development.
The exposed product was developed with a 0.85% by weight aqueous sodium carbonate solution (20-45 ° C.) using a DuPont C11 processor. The developer was sprayed at 10-25 Psi and the development speed was 3-15 ft / min.
After development, the dried product was baked in an air oven at a maximum temperature of 605 ° C. with a 40 minute cycle.
[0052]
3) Evaluation test
A. Evaluation sample
Samples of Examples 1 to 5 were prepared as described above using the components shown in Table 1.
[0053]
[Table 1]

[0054]
The glass binders used in Examples 1 to 5 can be produced from the compounds shown in Table 2 by a usual production method.
[0055]
[Table 2]

[0056]
B. Comparative sample
Comparison of conventional thick film resistor compositions containing 10.0% pyrochlore I and 5% ruthenium oxide as conductive components, 30% glass frit I and 25% glass frit II as inorganic binder, and 30% vehicle. A sample was used.
Here, the vehicle is a mixture of 10 to 30 parts by weight of ethyl cellulose, 90 to 70 parts by weight of β-terpineol and 10 parts by weight or less of the dispersant.
[0057]
C. Evaluation test
The compositions of Examples 1 to 5 and Comparative Samples shown in Table 1 were printed on a substrate, and the obtained patterns were dried and fired to obtain sheet resistance values (Ω / □), average dryness and fired film thickness, and resolution. It was measured. Here, the resolution is where one of the lines spreads on the radiation and the other of the lines converges toward the center. In the so-called fan-shaped pattern, how far is the resistor line narrowed by the microscope in the direction of decreasing width? It was observed whether it was formed without being cut, and the resistor line width immediately before the line was cut was measured and expressed in units of (mil).
The evaluation results are shown in Table 3.
[0058]
[Table 3]

[0059]
【The invention's effect】
Since the photosensitive resistor composition of the present invention is configured as described above, it is dried after printing on the substrate using this, exposed and developed, and then dried and fired while maintaining good electrical characteristics. A thick film resistor in which a fine pattern is formed can be obtained.
[0060]
The thick film resistors of the present invention can be patterned into any shape and dimensions smaller than is possible using conventional compositions and screen printing. With the patterned resistor of the present invention, precise resistor geometry and elimination of laser trimming are also achieved. These characteristics make it easy to pattern the resistor over a large area of the substrate in a precise arrangement and with a well-controlled thickness. Further, even when the resistor is formed as one of the components of the composite circuit product, the positional relationship of the resistor to the other elements is related to the screen printed capacitors and inductives in the multifunctional component. It can be selected accurately so that it can be used in combination with children.

Claims (6)

(a) at least one fine particle 5-17 ruthenium oxide and ruthenium pyrochlore oxide. 56 wt%, and
(b) 350 ℃ ~825 ℃ glass transition temperature and the fine particles of an inorganic binder 39 having a particle size of 0.1 to 10 [mu] m. 3 to 75 wt%
Or Ranaru inorganic solids 44.3 to 80 wt%, and
(d) an organic polymer binder,
(e) a photoinitiator,
(f) a photocurable monomer and
(g) an organic vehicle 55 made of an organic medium. 7-20 wt%
An aqueous developable photosensitive resistor composition for photolithography. Acid containing organic polymer binder (1) C ₁ -C ₁₀ alkyl acrylates or C ₁ -C ₁₀ alkyl methacrylate, styrene, a non-acidic comonomer and (2) an ethylenically unsaturated carboxylic acid including substituted styrene or combinations thereof The copolymer or interpolymer of comonomers, wherein the sum of all acidic comonomers comprises at least 15% by weight of the polymer and the organic polymer binder has a molecular weight (M _w ) of 50,000 or less. Composition.   The composition of claim 2 wherein the organic polymeric binder is a copolymer of methyl methacrylate.   The composition of claim 1 wherein the organic medium contains a dispersant.   A composition according to claim 1 which is developable in an aqueous solution containing 0.8% by weight sodium carbonate after image exposure to actinic light.   A method for forming a thick film resistor, comprising: applying the photosensitive resistor composition of claim 1 onto an insulating substrate, exposing the composition, and baking after development at a temperature of 500 ° C. to 1,000 ° C.