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
2000-10-10
2003-04-29
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
C430S271100, C560S053000, C560S055000, C560S081000, C560S082000, C562S489000, C564S347000, C558S401000, C549S543000, C568S631000, C568S715000
Reexamination Certificate
active
06555287
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is broadly concerned with new dyes or light attenuating compounds for incorporation into photolithographic compositions (e.g., anti-reflective coatings and contact or via hole fill compositions) utilized in the manufacturing of microdevices. More particularly, the light attenuating compounds comprise at least two reactive functional groups and are especially useful for absorbing light at wavelengths of from about 180-450 nm. Through these functional groups, the compounds can chemically bond with a polymer binder already present in the composition or can be polymerized with a precursor polymer to form a polymer binder for use in the composition without negatively affecting the spectral properties of the light attenuating compound.
2. Description of the Prior Art
Anti-reflective coatings (ARC) have long been used in semiconductor manufacturing to control standing waves and critical dimensions (CD) of the patterned photoresists used in microlithography. As the feature size on semiconductor devices continue to decrease, CD control becomes very critical.
Currently available compositions for use as ARC's in submicron microlithography typically comprise an organic polymer binder and an ultraviolet dye that is attached to the polymer binder by a functional group on the dye. This functional group is usually part of a conjugated, electronic structure that is responsible for the light absorbing properties of the dye. However, since reactions of the functional group alter the electronic structure of the dye, undesirable spectral shifts generally result when the dye is attached to the binder. Furthermore, a reduction in the light absorbing abilities of the dye may also occur if the functional group degrades (e.g., oxidizes) during the attachment reaction. Similar problems occur when the dye is incorporated into the polymer binder in a linear fashion using two-point attachment via two functional groups on the dye.
Thus, there is a need for a dye which can be attached to or polymerized with a polymer binder for incorporation into an ARC with minimal impact on the light absorbing abilities of the dye.
SUMMARY OF THE INVENTION
The present invention overcomes these problems by broadly providing a dye or light attenuating compound which can be incorporated into ARC's without negatively affecting the dye's light-absorbing abilities.
In more detail, the inventive dye has the structure of Formula I or Formula II.
Formula I
Formula II
wherein:
each cyclic group can be the same or different groups and is preferably individually selected from the group consisting of aromatic groups (with benzene rings being the most preferred aromatic group);
m=0-30, preferably 0-15, and more preferably 0-6;
each R
1
is individually a reactive group such as those selected from the group consisting of —OH, —COOH, —NH
2
, —COOR′ (with R′ being an alkyl group (preferably C
1
-C
8
)), —CH═CH
2
, and epoxy groups;
preferably all but one ring member of the cyclic group has an R
2
bonded thereto, and each R
2
is individually selected from the group consisting of hydrogen, alkyls, heteroalkyls, aryls, heteroaryls, ethers, thioethers, carboxylates, cyanos, halogens, R″—C═N—, R″—N═N′ (with R″ being hydrogen or an alkyl group (preferably C
1
-C
8
)), dialkylaminos, diarylaminos, and one of the following:
or
where n=0 or 1
in structure A, where EWG and R
3
do not form a cyclic unit:
EWG is an electron-withdrawing group such as those selected from the group consisting of carbonyls, cyanos, iminos, carboxylic acids, carboxylic esters, carboxamidos, carboximidos, and sulfonyls; and
R
3
is selected from the group consisting of hydrogen, alkyls, heteroalkyls, aryls, heteroaryls, carbonyls, cyanos, iminos, carboxylic acids, carboxylic esters, carboxamidos, carboximidos, and sulfonyls; and
in structure B, EWG and R
3
form a cyclic electron-withdrawing unit which includes one or more groups selected from the group consisting of carbonyls, cyanos, iminos, carboxylic acids, carboxylic esters, carboxamidos, carboximidos, and sulfonyls, and
in either Structure A or B, (*) indicates the point of attachment of R
2
to the cyclic group.
Even more preferably, the dye has the structure depicted in Formula III.
Formula III
wherein each n=1-30, and preferably 1-10, and each R
1
is individually a reactive group such as those selected from the group consisting of —OH, —COOH, —NH
2
, —COOR″ (with R′ being an alkyl group (preferably C
1
-C
8
)), —CH═CH
2
, and epoxy groups, with —OH groups being particularly preferred.
Examples of particularly preferred Structures B where EWG and R
3
form a cyclic electron-withdrawing unit include the structure depicted in Formula IV.
Formula IV
wherein each R
1
is individually a reactive group such as those selected from the group consisting of —OH, —COOH, —NH
2
, —COOR′ (with R′ being an alkyl group (preferably C
1
-C
8
)), —CH═CH
2
, and epoxy groups.
In each of the foregoing dye structures, the reactive functionalities (i.e., the R
1
groups) are electronically isolated from the light-absorbing portion (i.e., the cyclic group) of the structure so that spectral shifts and degradation are minimized or avoided when the dye is polymerized, crosslinked, or otherwise reacted. Additionally, it will be appreciated that the R
1
groups can be selected to react with, for example, aminoplast, polyepoxide, polyisocyanate, or polycarboxylic acid crosslinking agents, thus allowing for the design of a wider variety of polymer classes for incorporation into ARC's for use at wavelengths of about 180-450 nm.
In the embodiment illustrated in Formula IV, the dye comprises a blocked functionality on its light absorbing moiety which allows for selective dissolution in organic solvents or aqueous media. For example, the structure of Formula IV will hydrolyze in the presence of photogenerated acids (such as acids formed in photoresist layers upon exposure of the layer to ultraviolet light) to form a base-soluble carboxylic acid. Thus, because the developer is typically a base, the resulting ARC will be etchable and subsequent plasma etching will not be necessary.
The inventive dyes can be physically mixed with a polymer binder and crosslinking agent and dissolved in a solvent system to form a composition useful for forming an ARC which can absorb at a defined wavelength or can exhibit broadband absorption (e.g., at 193, 248, and 365 nm). However, it is particularly preferred that the dye be bonded to the polymer binder. In the latter instance, the dye can be bonded to a functional group on the polymer binder or it can be polymerized with precursor polymers (preferably by step-wise methods to form linear polymers) without interfering with the spectral properties of the dye. That is, the absorbance at a wavelength of from about 180-450 nm of an ARC comprising an inventive dye bonded to or polymerized with a polymer binder is at least about 25%, preferably at least about 35%, and more preferably at least about 50% of the absorbance of the dye alone (i.e., of the dye when it is not bonded to or polymerized with another compound).
In applications where the dye is polymerized with a precursor polymer, the polymerization reaction preferably results in bonds being formed between the precursor polymer and the R
1
groups on the dye structure. The resulting polymer can be incorporated into an anti-reflective composition and should have a weight average molecular weight of from about 20,000-100,000 Daltons.
Preferred precursor polymers include those selected from the group consisting of polyesters, polyacrylates, polyheterocyclics, polyetherketones, polyisocyanates, polyhydroxystyrene, polycarbonates, polyepichlorohydrin, polyvinyl alcohol, oligomeric resins, and mixtures thereof. Suitable solvent systems comprise solvents selected from the group consisting of ethylene glycol monomethyl ether acetate, propylene glycol monomethyl
Ashton Rosemary
Brewer Science Inc.
Hovey & Williams, LLP
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