Radiation imagery chemistry: process – composition – or product th – Imaged product – Including resin or synthetic polymer
Reexamination Certificate
2000-02-09
2002-01-22
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaged product
Including resin or synthetic polymer
C430S192000, C430S193000, C430S270100, C430S326000
Reexamination Certificate
active
06340546
ABSTRACT:
This application claims prior of Japanese Patent Application No. 11-31936, filed Feb. 9, 1999, the entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The invention relates to positive photosensitive resin compositions, particularly to positive photosensitive resin compositions which, on heating, become heat-resistant polyimide polymers suitable for surface-protecting films, interlayer insulating films and others for electronic parts such as semiconductor elements. It also relates to methods of forming relief patterns and to electronic parts using such compositions.
(b) Description of the Related Art
Polyimides have good heat rsistance and good mechanical properties, and are readily formed into films of which the surface could be well planarized. Having those advantages, they are widely used for surface-protecting films, interlayer insulating films and others for semiconductor devices. Where polyimides are used for surface-protecting films or interlayer insulating films, forming through-holes and the like in such films is achieved mainly by etching processes using positive photo-resists. Such processes, however, involve steps of appying and removing the photo-resists, which complicate the processes. To simplify the working process, heat-resistant materials with photosensitivity have heretofore been studied.
As to photosensitive polyimide compositions, for example, known are (a) a polyimide precursor composition in which is introduced photosensitive groups through ester bonding (Japanese Patent Application Examined Publication No. 52-30207), and (b) a polyamidate composition in which is added a compound that has carbon-carbon double bonds capable of being dimerized or polymerized by the action of chemical rays, amino groups and an aromatic bisazide (Japanese Patent Application Examined Publication No. 3-36861). To form patterns, photosensitive polyimide precursor compositions are generally applied in solution form onto a substrate and dried, and then exposed to active rays via a mask and developed.
The compositions (a) and (b), however, require an organic solvent as a developer. When waste developers are treated, the large quantities of developers that are several times that of the photosensitive polyimide precursor compositions load the environment heavily. In recent years, for the preservation of the environment, there has been increasing demand for photosensitive polyimide compositions that are developable with aqueous developers and enable easy treatment of waste developers. Further, the compositions (a) and (b) are both negative ones, and involve the problem that the mask for exposure needs to be changed to switch from an etching process using positive photo-resists to the process using negative photosensitive polyimide precursors.
As to positive photosensitive polyimide precursor compositions, for example, known are (c) a polyimide precursor in which is introduced an o-nitrobenzyl group through ester bonding (Japanese Patent Application Unexamined Publication No. 60-37550), (d) a composition comprising a polyamidate and an o-quinonediazide compound (Japanese Patent Application Unexamined Publication No. 2-181149), (e) a composition comprising a carboxyl group-having polyamidate and an o-quinonediazide compound (Japanese Patent Application Unexamined Publication No. 4-168441), and (f) a composition comprising a hydroxyl group-having polyamidic acid or polyamidate and an o-quinonediazide compound (Japanese Patent Application Unexamined Publication No. 3-115461).
Incidentally, semiconductor elements have been increasingly integrated with years, requiring improved fine processing techniques. A means for enabling fine processing is exposure using light of shorter wavelength, and g-line (wavelength: 436 mn), which have been mainly used as the exposure light to pattern positive photo-resists, are being replaced by exposure to i-line (wavelength: 365 nm). Accordingly, photosensitive polyimide precursors are also required to be able to form patterns with i-line, to accommodate them to exposure apparatuses using i-line.
The positive photosensitive polyimide precursor composition (c), however, is sensitive mainly to lights of wavelengths of 300 nm or less, and has poor sensitivity to i-line. The positive photosensitive resin compositions (d) and (e) have the shortcoming of poor storage stability. The Japanese Patent Unexamined Publication No. 3-115461 does not disclose or suggest exposure with i-line, and the positive photosensitive resin composition (f) disclosed therein, in fact, has poor sensitivity to i-line.
SUMMARY OF THE INVENTION
An object of the invention is to solve the problems in the above-described prior art by providing a positive photosensitive resin composition which is highly sensitive to lights including i-line and has good storage stability.
Accordingly, the invention provides a positive photosensitive resin composition comprising:
(A) a polyamidate having repetitive units of general formula (I)
wherein R
1
is a tetravalent organic group, R
2
is a divalent organic group having a phenolic hydroxyl group, three R
3
groups and three R
4
groups each independently are an alkyl group or a hydrogen atom, and at least two R
3
groups and at least two R
4
groups are alkyl groups, and
(B) a compound capable of generating an acid when exposed to light.
Another object of the present invention is to provide a positive photosensitive resin composition to be used for exposure with i-line.
Accordingly, in one embodiment, the positive photosensitive resin composition is to be exposed to i-line.
Another object of the present invention is to provide a positive photosensitive resin composition which further has good heat resistance.
Accordingly, in one embodiment, the group represented by R
1
is a tetravalent organic group which has a condensed polycyclic structure consisting of 2 to 5 benzene rings or a polycyclic structure wherein two or three aromatic rings are linked to each other through one or two bonds selected from the group consisting of a single bond, an ether bond (—O—), an isopropylidene bond (—C(CH
3
)
2
—), a hexafluoroisopropylidene bond (—C(CF
3
)
2
—), a sulfone bond (—SO
2
—), a methylene bond (—CH
2
—) and a carbonyl bond (—CO—), and the group represented by R
2
is a divalent organic group which has an aromatic ring or a polycyclic structure wherein two or three aromatic rings are linked to each other through one or two bonds selected from the group consisting of a single bond, an ether bond, an isopropylidene bond (—C(CH
3
)
2
—), a hexafluoroisopropylidene bond, a sulfone bond, a methylene bond and a carbonyl bond, and has at least one phenolic hydroxyl group.
In one embodiment, the tetravalent organic group represented by R
1
is selected from the group consisting of
and the group —C(═O)OC(R
3
)
3
is linked to R
1
at an ortho or peri position relative to one of the amide bonds, and the group —C(═O)OC(R
4
)
3
is linked to R
1
at an ortho or peri position relative to the other amide bond;
and the divalent organic group represented by R
2
is selected from the group consisting of
Another object of the invention is to provide a positive photosensitive resin composition which has good storage stability and is particularly highly sensitive to lights including i-line.
Accordingly, in one embodiment, the invention provides a positive photosensitive resin composition which comprises
(A′) a polyamidate having repetitive units of general formula (I′)
wherein R
1
is a tetravalent organic group, R
6
is a divalent organic group selected from
three R
3
groups and three R
4
groups each independently are an alkyl group or a hydrogen atom, and at least two R
3
groups and at least two R
4
groups are alkyl groups, and
(B) a compound capable of generating an acid when exposed to light.
Another object of the invention is to provide a positive photosensitive resin composition which is less shrinkable when heat-treated after development.
Accordingly, in one embodiment, the gr
Chu John S.
Griffin & Szipl, P.C.
Hitachi Chemical Dupont Microsystems Ltd.
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