Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2000-06-01
2002-06-04
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S018000, C430S191000, C430S193000, C430S326000, C430S330000
Reexamination Certificate
active
06399267
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a radiation sensitive resin composition and to use of the same in an interlaminar insulating film. More specifically, it relates to a positive radiation sensitive resin composition suitable for the formation of an interlaminar insulating film by photolithography and to use of the same in an interlaminar insulating film, particularly a liquid crystal display element, integrated circuit element, magnetic head element, solid image pick-up element or the like.
Generally speaking, an interlaminar insulating film for insulating wiring layers from each other is formed in electronic parts such as thin film transistor (to be abbreviated as “TFT” hereinafter) liquid crystal display elements, magnetic head elements, integrated circuit elements and solid image pick-up elements. Photolithography which uses a radiation sensitive resin composition and is characterized in that the number of steps for obtaining a required interlaminar insulating film pattern is small and an interlaminar insulating film having satisfactory flatness is obtained is employed to form the interlaminar insulating film.
In the step of forming an interlaminar insulating film from a radiation sensitive resin composition, the optimum process conditions are selected and employed for each material constituting an electronic part in order to balance among such properties as resolution, solvent resistance, adhesion to a substrate and storage stability. When a high temperature is required for the processing and molding of an interlaminar insulating film under the above process conditions, elements other than the interlaminar insulating film are damaged by heating, whereby characteristic properties targeted for the electronic part may not be obtained. For example, a magnetic head (GMR head) comprising a great magnetic resistance film is used to increase reproduction,output thereof so as to improve the surface recording density of a hard disk drive. If this GMR head is heated at a temperature higher than 200° C., the direction of magnetization will become instable. Therefore, it must be avoided to heat the GMR head at a temperature higher than 200° C. However, in order to produce the GMR head, a recording coil having an interlaminar insulating film must be fabricated after the formation of a great magnetic resistance film according to the structure of the GMR head. To achieve a satisfactory function for the interlaminar insulating film, a conventional photosensitive resin composition which constitutes the interlaminar insulating film must be heated at a temperature higher than 200° C., thereby instabilizing the direction of magnetization of the great magnetic resistance film. Conventional photosensitive resin compositions involve such problems as low solvent resistance because a curing reaction does not proceed sufficiently at a heat treatment temperature lower than 200° C. or the formation of air bubbles between layers at the time of laminating because the curing reaction is accompanied by degassing.
That is, there has been unknown a photosensitive resin composition which allows for the processing and molding of an interlaminar insulating film at a low temperature that does not damage other element materials constituting an electronic part and has required resolution, solvent resistance, adhesion and storage stability as an interlaminar insulating film.
It is an object of the present invention which has been made under the above circumstances to provide a radiation sensitive resin composition which can be processed and molded at low temperatures and has required resolution, solvent resistance, adhesion to a substrate and storage stability as an interlaminar insulating film.
It is another object of the present invention to provide a process for producing an interlaminar insulating film from the above radiation sensitive resin composition.
It is still another object of the present invention to use the above radiation sensitive resin composition in an interlaminar insulating film.
It is a further object of the present invention to provide an interlaminar insulating film formed from the above radiation sensitive resin composition.
Other objects and advantages of the present invention will become apparent from the following description.
According to the present invention, firstly, the above objects and advantages of the present invention are attained by a radiation sensitive resin composition comprising:
(A) a copolymer (to be referred to as “copolymer (A)”) obtained by copolymerizing (a1) at least one carboxylic acid compound (to be referred to as “compound (a1)” hereinafter) selected from the group consisting of an unsaturated carboxylic acid and an unsaturated carboxylic anhydride, (a2) at least one unsaturated epoxy compound (to be referred to as “compound (a2)” hereinafter) selected from the group consisting of a monomer represented by the following formula (1):
wherein R is a hydrogen atom or methyl group, R
1
is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 6,
and a monomer represented by the following formula (2):
wherein R
2
is a hydrogen atom or methyl group, p is an integer of 1 to 6, and q is an integer of 1 to 6, and (a3) an olefinic unsaturated compound (to be referred to as “compound (a3)” hereinafter) other than the above (a1) and (a2); and
(B) a 1,2-quinonediazide compound.
Secondly, the above objects and advantages of the present invention are attained by a process for producing an interlaminar insulating film, comprising the steps of:
(1) preparing a substrate for an interlaminar insulating film having a thin film formed from the above radiation sensitive resin composition of the present invention;
(2) exposing the thin film to radiation through a predetermined pattern mask;
(3) developing the exposed thin film with an alkali developer to form a thin film pattern; and
(4) heating the thin film pattern at a temperature lower than 200° C.
Thirdly, the above objects and advantages of the present invention are attained by use of the above radiation sensitive resin composition of the present invention in an interlaminar insulating film.
In the fourth place, the above objects and advantages of the present invention are attained by an interlaminar insulating film formed from the above radiation sensitive resin composition of the present invention.
The term “radiation” as used herein means ultraviolet radiation, far ultraviolet radiation, X-radiation, electron beams, molecular beams, &ggr;-radiation, synchrotron radiation, proton beams and the like.
The radiation sensitive resin composition of the present invention will be detailed hereinunder.
The radiation sensitive resin composition of the present invention comprises a copolymer (A) and a 1,2-quinonediazide compound (B).
Copolymer (A)
The copolymer (A) can be produced, for example, by radical polymerizing the compound (a1), compound (a2) and compound (a3) in a solvent in the presence of a polymerization initiator.
The copolymer (A) used in the present invention contains a constituent unit derived from the compound (a1) in an amount of preferably 5 to 40 wt %, particularly preferably 10 to 35 wt %. When the amount of this constituent unit is smaller than 5 wt %, the copolymer hardly dissolves in an alkali aqueous solution and when the amount of this constituent unit is larger than 40 wt %, the solubility in an alkali aqueous solution of the copolymer tends to become too large. Illustrative examples of the compound (a1) include carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid and itaconic acid: anhydrides of these dicarboxylic acids; mono[(meth)acryloyloxyalkyl] esters of polycarboxylic acids (i.e. bivalent and polyvalent carboxylic acids) such as mono[2-(meth)acryloyloxyethyl]succinate and mono[2-(meth)acryloyloxyethyl]phthalate; and mono(meth)acrylates of polymers having a carboxyl group and hydroxyl group at bot
Endo Masayuki
Nishimura Isao
Suzuki Masayoshi
Yonezawa Fumiko
LandOfFree
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