Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2001-03-22
2003-07-15
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...
C430S270100, C430S326000, C430S330000, C430S905000
Reexamination Certificate
active
06593056
ABSTRACT:
TECHNICAL FIELD
This invention relates to a chemically amplified positive resist composition having a high resolution, dry etching resistance, and minimized slimming of a pattern film after development, and useful as a micropatterning material especially for the manufacture of VLSI.
It also relates to a chemically amplified positive resist composition for forming a contact hole pattern by the thermal flow process. While a method for forming a contact hole pattern using a chemically amplified positive resist composition comprising a polymer as the base resin involves the thermal flow step of heat treating the contact hole pattern for further reducing the size of contact holes, the invention relates to the resist composition to which a compound having functional groups capable of crosslinking with the polymer is added so that the size reduction by thermal flow becomes easy to control. The invention further relates to a method for forming a microsize contact hole pattern in the manufacture of VLSIs.
BACKGROUND ART
While a number of recent efforts are being made to achieve a finer pattern rule in the drive for higher integration and operating speeds in LSI devices, deep-ultraviolet, EB, EUV and x-ray lithography is thought to hold particular promise as the next generation in microfabrication technology. Deep-UV lithography is capable of achieving a minimum feature size of 0.3 &mgr;m or less and, when a resist having low light absorption is used, can form patterns with sidewalls that are nearly perpendicular to the substrate.
Recently developed acid-catalyzed chemically amplified positive resists, such as those described in JP-B 2-27660, JP-A 63-27829, U.S. Pat. No. 4,491,628 and U.S. Pat. No. 5,310,619, utilize a high-intensity KrF or ArF excimer laser as the deep-UV light source. These resists, with their excellent properties such as high sensitivity, high resolution, and good dry etching resistance, are especially promising for deep-UV lithography.
Such chemically amplified positive resist compositions include two-component systems comprising a base resin and a photoacid generator, and three-component systems comprising a base resin, a photoacid generator, and a dissolution regulator having acid labile groups.
For example, JP-A 62-115440 describes a resist composition comprising poly-4-tert-butoxystyrene and a photoacid generator, and JP-A 3-223858 describes a similar two-component resist composition comprising a resin bearing tert-butoxy groups within the molecule, in combination with a photoacid generator. JP-A 4-211258 describes a two-component resist composition which is comprised of polyhydroxystyrene bearing methyl, isopropyl, tert-butyl, tetrahydropyranyl, and trimethylsilyl groups, together with a photoacid generator. JP-A 6-100488 discloses a resist composition comprising a polydihydroxystyrene derivative, such as poly[3,4-bis(2-tetrahydropyranyloxy)styrene], poly[3,4-bis(tert-butoxycarbonyloxy)styrene] or poly[3,5-bis(2-tetrahydropyranyloxy)styrene], and a photoacid generator. These resists, however, have the drawbacks of slimming of a pattern film after development with an aqueous base solution and poor resistance to dry etching.
Also known in the art are resist compositions using copolymers of hydroxystyrene with (meth)acrylate for achieving a higher transparency and improving the adhesion to the substrate as disclosed in JP-A 8-101509 and 8-146610. The resist compositions of this type suffer from low heat resistance, partial pattern collapse, and pattern shape footing.
Improvement and development efforts have been continuously made on the base resin in resist compositions of this type. JP-A 10-207066 discloses a resist composition comprising a base resin which is crosslinked with crosslinking groups having C—O—C linkages and a photoacid generator wherein the crosslinking groups are eliminated under the action of acid generated from the photoacid generator upon exposure, achieving a high contrast and high resolution.
Even when any base resin designed to enhance the resolving power is used in such chemically amplified positive resist compositions, it is yet difficult to reach a contact hole size of 0.20 &mgr;m or less. There are available no resist compositions for forming a contact hole pattern satisfying the requirement of LSI devices of the next generation.
On the other hand, the known technology of forming a contact hole size of 0.20 &mgr;m or less is to heat treat a contact hole pattern for causing the resist film to flow and reducing the contact hole size. This technology is known as thermal flow process. The use of the thermal flow process enables formation of a miniature contact hole size as fine as 0.10 &mgr;m or 0.15 &mgr;m.
In forming microsize contact holes by the thermal flow process, however, it is very difficult to control the heat treating temperature so as to provide a shrinkage matching with the desired contact hole size. That is, the thermal flow process has the drawback that even a slight variation of heating temperature brings about a substantial variation of contact hole size.
Referring to
FIG. 1
, there is illustrated in cross section a resist film
2
on a substrate
1
, a contact hole
3
being formed through the resist film
2
. The contact hole having undergone the thermal flow process has a profile as shown in
FIG. 1
, that is, a cross-sectional profile bowed at corners. The thermal flow process also has the problem that the profile of a contact hole is deteriorated.
SUMMARY OF THE INVENTION
An object of the invention is to provide a chemical amplification type, positive working resist composition which has a higher sensitivity, resolution, dry etching resistance and process adaptability than conventional resist compositions, and is improved in the slimming of a pattern film after development with an aqueous base solution.
Another object of the invention is to provide a novel and improved chemical amplification type, positive working resist composition which has controllable process adaptability relative to the heat treating temperature when a microsize contact hole pattern is conventionally formed by the thermal flow process, and thus has satisfactory practical utility. A further object is to provide a novel and improved method for forming a contact hole pattern.
It has been found that using a chemically amplified positive resist composition comprising a compound containing at least two functional groups of the general formula (1) in a molecule, a resist pattern can be formed with the advantages of improved process control and practical utility.
Herein R
1
to R
4
are hydrogen or straight, branched or cyclic alkyl groups of 1 to 12 carbon atoms, and a pair of R
1
and R
3
, or a pair of R
2
and R
3
, taken together, may form a ring.
When only a polyhydroxystyrene derivative is formulated in a resist composition as the base resin, there arise such drawbacks as slimming of a pattern film after development with an aqueous base solution and poor dry etching resistance. Even when a copolymer of hydroxystyrene with (meth)acrylate is formulated in a resist composition as the base resin, the above drawbacks are not fully overcome. It has been found that an allyloxy compound having at least two functional groups of formula (1) in a molecule is an effective additive to a chemically amplified positive resist composition, and more specifically, that a chemically amplified positive resist composition comprising the allyloxy compound, a polymer, a photoacid generator and an organic solvent has a high sensitivity, high resolution, dry etching resistance, and process adaptability, and is improved in the slimming of a pattern film after development with an aqueous base solution. The composition is thus well suited for practical use and advantageously used in precise microfabrication, especially in VLSI manufacture. When a vinyloxy compound is added in an analogous way, similar effects are exerted, but accompanied by such drawbacks as a number of foreign particles in the pattern formed and the lack of storage stability. T
Koizumi Kenji
Takeda Takanobu
Takemura Katsuya
Watanabe Jun
Chu John S.
Shin-Etsu Chemical Co. , Ltd.
LandOfFree
Chemically amplified positive resist composition and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Chemically amplified positive resist composition and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemically amplified positive resist composition and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3046943