Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
1999-08-13
2002-10-01
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S921000, C568S018000, C568S023000, C568S028000, C568S030000
Reexamination Certificate
active
06458506
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to new photoacid generator compounds (“PAGs”) and photoresist compositions that comprise such compounds. In particular, the invention relates to photoacid generator compounds that generate an anthracene acid upon exposure to activating radiation, particularly anthracene sulfonate acids such as acids that include 9,10-dialkoxyanthracene-2-sulfonate moieties. Positive- and negative-acting chemically amplified resists that contain such PAGs and that are imaged with I-line (365 nm) radiation are particularly preferred.
2. Background
Photoresists are photosensitive films for transfer of images to a substrate. They form negative or positive images. After coating a photoresist on a substrate, the coating is exposed through a patterned photomask to a source of activating energy such as ultraviolet light to form a latent image in the photoresist coating. The photomask has areas opaque and transparent to activating radiation that define an image desired to be transferred to the underlying substrate. A relief image is provided by development of the latent image pattern in the resist coating. The use of photoresists is generally described, for example, by Deforest, Photoresist Materials and Processes, McGraw Hill Book Company, New York (1975), and by Moreau, Semiconductor Lithography, Principals, Practices and Materials, Plenum Press, New York (1988).
Known photoresists can provide features having resolution and size sufficient for many existing commercial applications. However for many other applications, the need exists for new photoresists that can provide highly resolved images of submicron dimension.
Various attempts have been made to alter the make-up of photoresist compositions to improve performance of functional properties. Among other things, a variety of photoactive compounds have been reported for use in photoresist compositions. See, e.g., U.S. Pat. No. 4,450,360 and European Application 615163.
More recently, certain “chemically amplified” photoresist compositions have been reported. Such photoresists may be negative-acting or positive-acting and rely on multiple crosslinking events (in the case of a negative-acting resist) or deprotection reactions (in the case of a positive-acting resist) per unit of photogenerated acid. In other words, the photogenerated acid acts catalytically. In the case of positive chemically amplified resists, certain cationic photoinitiators have been used to induce cleavage of certain “blocking” groups pendant from a photoresist binder, or cleavage of certain groups that comprise a photoresist binder backbone. See, for example, U.S. Pat. Nos. 5,075,199; 4,968,851; 4,883,740; 4,810,613; and 4,491,628, and Canadian Patent Application 2,001,384. Upon selective cleavage of the blocking group through exposure of a coating layer of such a resist, a polar functional group is provided, e.g., carboxyl, phenol or imide, which results in different solubility characteristics in exposed and unexposed areas of the resist coating layer.
SUMMARY OF THE INVENTION
I have now discovered novel photoacid generator compounds (PAGs) for use in either positive-acting or negative-acting photoresist compositions.
In particular, the invention provides photoacid generators that can produce an optionally substituted anthracene sulfonic acid upon exposure to activating radiation, particularly an alkoxy anthracene sulfonic acid such as 9,10-dialkoxyanthracene-2-sulfonic acid; anthracene disulfonic acid such as 9,10-dialkoxyanthracene-2,6-disulfonic acid and 9,10-dialkoxyanthracene-2,5-disulfonic acid; and anthracene acids that have both sulfonic acid and alkanoyl (e.g.—COOR where R is optionally substituted C
1-12
alkyl, preferably C
1-6
alkyl) moieties such as 9,10-dialkoxyanthracene-2-sulfonic acid-7-methylester and the like.
Preferably, PAGs of the invention are used in positive-acting or negative-acting chemically amplified photoresists, i.e. negative-acting resist compositions which undergo a photoacid-promoted crosslinking reaction to render exposed regions of a coating layer of the resist less developer soluble than unexposed regions, and positive-acting resist compositions which undergo a photoacid-promoted deprotection reaction of acid labile groups of one or more composition components to render exposed regions of a coating layer of the resist more soluble in an aqueous developer than unexposed regions. A preferred imaging wavelength is I-line (365 nm), although other exposure wavelengths also can be utilized, including shorter wavelengths such as sub-300 nm wavelengths e.g. 248 nm. Longer wavelengths such as G-line (435 nm) also can be employed, particularly where a sensitizer is employed as an additional resist component.
The invention also provide methods for forming relief images of the photoresists of the invention, including methods for forming highly resolved patterned photoresist images (e.g. a patterned line having essentially vertical sidewalls) of sub-micron and even sub-half or sub-quarter micron dimensions.
The invention further provides articles of manufacture comprising substrates such as a microelectronic wafer or a flat panel display substrate having coated thereon the photoresists and relief images of the invention. Other aspects of the invention are disclosed infra.
DETAILED DESCRIPTION OF THE INVENTION
In a first aspect of the invention, iodonium PAGs are provided that can generate an anthracene sulfonic acid, such as diaryliodonium salts that have a counter anion of an anthracene sulfonate. Generally preferred are optionally substituted diphenyliodoium salts that have such an anthracene sulfonate counter anion, such as PAGs of the following Formula I:
wherein R
1
and R
2
are each independently a non-hydrogen substituent such as halo; hydroxy; nitro; cyano; sulfonyl; optionally substituted alkyl preferably having from 1 to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionally substituted alkoxy preferably having from 1 to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionally substituted aminoalkyl preferably having from 1 to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionally substituted alkylthio preferably having from 1 to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionally substituted alkylsulfinyl preferably having from 1 to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionally substituted alkylsulfonyl preferably having from 1 to about 20 carbon atoms, more preferably 1 to about 8 carbon atoms; optionally substituted aryloxy such as phenoxy; optionally substituted aralkyl such as benzyl; optionally substituted alkanoyl preferably having from 1 to about 20 carbons atoms with acetyl being a preferred group; optionally substituted carbocyclic aryl such as phenyl, naphthyl, biphenyl, and the like; optionally substituted heteroaromatic or heteroalicyclic having 1 to 3 rings, 3 to 8 ring members in each ring and from 1 to 3 hetero atoms such as coumarinyl, quinolinyl, pyridyl, pyrazinyl, pyrimidyl, furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl, benzofuranyl, benzothiazol, tetrahydrofuranyl, tetrahydropyranyl, piperdinyl, morpholino, pyrrolindinyl, etc.; and the like;
R
3
and R
4
are the same or different and are selected from the same group as defined for R
1
and R
2
above, and preferably R
3
and R
4
are alkoxy such as preferably C
1-12
alkoxy, more preferably C
1-6
alkoxy such as methoxy, ethoxy, propoxy, etc., and preferably R
3
and R
4
are substituted at the 9 and 10 position of the anthracene ring, respectively;
preferably the SO
3
31
group is substituted at the 2-position of the anthracene ring;
m and n are each independently an integer of from 0 (where the respective phenyl is fully hydrogen-substituted) to 5, and preferably m and n are each 0, 1, or 2; and
o and p are each independently an integer of 0 or greater, wherein the sum of o and p is 9 or less, and preferably o and p are each 1.
Also preferred are optio
Ashton Rosemary
Corless Peter F.
O'Day Christine C.
Shipley Company LLC
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