Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
1998-02-23
2003-07-01
Beck, Shrive P. (Department: 1762)
Stock material or miscellaneous articles
Composite
Of silicon containing
C106S287130, C106S287160, C106S287190, C524S588000, C528S012000, C528S014000, C528S017000
Reexamination Certificate
active
06586104
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a coating liquid for forming a transparent coating and a substrate with transparent coating formed from the coating liquid. More particularly, the present invention is concerned with a coating liquid capable of forming on a substrate surface a coating film which has excellent resistances to heat, moisture, chemicals and plasma, ensures a low level of gas elimination and exhibits desirable transparency and flatness and is concerned with a substrate with transparent coating having the above coating film formed on a substrate surface.
BACKGROUND ART
In the field of, for example, electronic materials, organic resins such as acrylic and polyester resins are commonly used as materials for forming flattening coating films or insulating protective coating films.
For example, in the TFT liquid crystal display, the construction is employed such that, for flattening the irregularity on the side of a substrate with TFT array, an organic resin coating having a thickness of about some microns is formed on a substrate including driving circuits to thereby flatten the substrate surface and, thereafter, a display electrode of, for example, ITO is mounted thereon.
However, the above involves problems in that, in the formation of the display electrode (ITO film) on a flattening coating film according to the sputtering method or the like, the temperature beyond which the organic flattening coating film cannot be resistant to heat is so low (150 to 250° C.) that high temperature and plasma resistances are poor thereby inviting a discoloration of coating film and a drop of light transmission. Further, the problem has been encountered such that, when the inside of the apparatus is evacuated prior to sputtering, gas components such as uncured components and desorption components are desorbed from the resin coating film to thereby retard the vacuum reaching time in the apparatus or pollute the inside of the apparatus.
Moreover, the use of a coating film prepared from an organic resin as a color filter protective coating film of a liquid crystal display equipped with a color filter also encounters the heat resistance problem.
On the other hand, an inorganic coating film is superior to the above organic resin coating film with respect to high temperature and plasma resistances.
Examples of such inorganic coating films include dry process formed coating films of SiO
2
, Ta
2
O
5
and Si
3
N
4
and coating films of SOG which is a hydrolyzate of an organosilicon compound such as an alkoxysilane. The former dry process formed coating films invite high process cost, and the latter SOG coating films require curing of the coating films at about 400° C. or higher to thereby disenable use as a color filter protective coating film whose heat resistance temperature is 250° C. or below. Moreover, these inorganic coating films have drawbacks in that, when the thickness of coating film is increased so as to enable flattening, cracks occur. In semiconductor devices, the above coating film of SOG is used as an insulating film for effecting an insulation between a substrate and a metal wiring layer such as a wiring layer of aluminum or between metal wiring layers. In these semiconductor devices, an interlayer connecting hole (contact hole) is formed between a lower wiring layer and an upper wiring layer of multiple wiring layers and, thereafter, the resist used during the formation of the interlayer connecting hole is removed by an oxygen plasma asher device. Thus, the problem is encountered that, at that time, the film surface exposed to the interlayer connecting hole is oxidized by oxygen plasma to thereby become porous in the SOG coating film, which is composed of a hydrolyzate of an organosilicon compound. The resultant porous portion adsorbs a large amount of water which is released during, for example, the heating conducted at a later stage thereby inviting a connection failure between upper and lower wiring layers.
Furthermore, a coating film obtained from an alkyltrihydroxysilane polymer can be mentioned as an organic/inorganic composite coating film. This coating film permits a thickness increase, so that desirable flatness can be imparted thereto. However, this coating film has a drawback in that it cannot be satisfactorily cured by heating at about 300° C. or below, resulting in a poor film strength. Further, there is the problem that the coating film per se has high hydrophobicity, so that, for example, when resists are applied to the coating film, a coating liquid repulsion occurs thereby rendering coating film formation difficult.
The present invention has been made with a view toward solving the above problems of the prior art. Therefore, an object of the present invention is to provide a coating liquid for forming a transparent coating, which contains fine particles of an inorganic compound and a hydrolyzate of an organosilicon compound (silsesquioxane polymer).
Other objects of the present invention are to provide a substrate with transparent coating formed from the above coating liquid, to provide a liquid crystal display having a flattening coating film formed from the above coating liquid, to provide a liquid crystal display having a color filter with protective coating film formed from the above coating liquid and to provide a semiconductor device having an insulating coating film formed from the above coating liquid.
DISCLOSURE OF THE INVENTION
The coating liquid for forming a transparent coating according to the present invention comprises:
fine particles of an inorganic compound, and
a hydrolyzate of an organosilicon compound represented by the general formula (I):
R
n
Si(OR′)
4−n
(I)
wherein R and R′ represent organic groups which may be identical to each other or different from each other, and n is an integer of 1 to 3.
The above organosilicon compound is preferably a trifunctional alkoxysilane represented by the general formula:
RSi(OR′)
3
(II)
wherein R and R′ represent organic groups which may be identical to each other or different from each other.
The above organosilicon compound hydrolyzate is preferably a hydrolyzate of an organosilicon compound containing a transition metal element.
This hydrolyzate of transition metal containing organosilicon compound is preferably one obtained by hydrolyzing a mixture of the organosilicon compound represented by the general formula (I) and a transition metal compound in an organic solvent containing water.
The above inorganic compound fine particles are preferably fine particles of an oxide of at least one element selected from the group consisting of Ti, Zr, V, Nb, Cr, Mo, W, Al, Mn, Fe, Co, Ni and Si.
The substrate with transparent coating according to the present invention comprises a transparent coating film formed from the above coating liquid for forming a transparent coating.
The first liquid crystal display according to the present invention comprises a liquid crystal display element having a transparent flattening coating film formed from the above coating liquid for forming a transparent coating.
The second liquid crystal display according to the present invention comprises a color filter having a transparent protective coating film formed from the above coating liquid for forming a transparent coating.
The semiconductor device according to the present invention comprises a semiconductor element having an insulating coating film formed from the above coating liquid for forming a transparent coating.
BEST MODE FOR CARRYING OUT THE INVENTION
The coating liquid for forming a transparent coating, substrate with transparent coating and use thereof according to the present invention will be described in detail below.
Coating Liquid for Forming Transparent Coating
The coating liquid for forming a transparent coating according to the present invention comprises fine particles of an inorganic compound and a hydrolyzate of an organosilicon compound represented by the general formula (I).
(Fine Particles of Inorganic Compound)
The inorganic compound
Komatsu Michio
Koyanagi Tsuguo
Matsuda Masayuki
Yoshida Nobuaki
Catalysts & Chemicals Industries Co. Ltd.
Tsoy Elena
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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