Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2001-09-12
2003-04-22
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...
C430S192000, C430S193000, C430S326000
Reexamination Certificate
active
06551755
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a positive photoresist composition which is satisfactory in sensitivity, definition and depth of focus (DOF) properties, can form a resist pattern with a good shape especially in the formation of a mixture of an isolation pattern and a dense pattern and can minimize the formation of a back taper shape of an isolation resist pattern induced by shift of the focus to the minus side.
2. Description of the Related Art
In the manufacture of an ultralarge-scale integrated circuit (ULSI) where a high definition of not more than half a micrometer, in particular, of not more than 0.35 &mgr;m is required, demands have been made on photoresist compositions which can form a resist pattern satisfactory in sensitivity, definition, and DOF properties and having a good shape.
Separately, the manufacture of a highly value-added logic integrated circuit (logic IC) has received attention in recent years. Such a logic IC has a complicated wiring pattern including large portions of irregularly formed line-and-space (hereinafter referred to as “L&S”). In contrast, a dynamic random access memory (DRAM) chip includes large portions of regularly formed L&S.
In a photolithographic process using a photoresist composition, demands have been made to form a resist pattern having a good pattern shape not only in regions where L&S is regularly formed, i.e., in dense pattern regions, but also in regions where L&S is irregularly formed, i.e., in isolation pattern regions.
However, in the formation of an ultrafine resist pattern of not more than half a micrometer, particularly of not more than 0.35 &mgr;m, resist patterns having good shapes both in dense patterns and isolation patterns cannot be significantly formed. Specifically, if exposure conditions are changed to yield rectangular dense patterns with good shapes, the shapes of isolation patterns are deteriorated, and, in contrast, if exposure conditions are changed to yield rectangular isolation patterns with good shapes, the shapes of dense patterns are deteriorated.
Consequently, mixed resist patterns including both dense patterns and isolation patterns cannot be significantly formed with good shapes concurrently.
In addition, positive photoresist compositions are liable to invite back taper shapes of isolation patterns, which is caused by sifts of the focus to the minus side, and are liable to induce twist of pattern and exhibit deteriorated focal depth range (DOF) properties in isolation patterns.
Under these circumstances, to concurrently form a mixed resist pattern including both a dense pattern and an isolation pattern with satisfactory sensitivity, definition and DOF properties in the formation of an ultrafine resist pattern of not more than half a micrometer, particularly of not more than 0.35 &mgr;m, demands have been made on positive photoresist compositions that can concurrently form a dense pattern and an isolation pattern with good shapes and can minimize the formation of a back taper shape of the isolation resist pattern induced by shift of the focus to the minus side.
Japanese Patent Application Laid-Open No. 6-167805 (Reference 1) discloses a positive photoresist composition containing, as a photosensitive ingredient, a quinonediazidosulfonyl ester of a compound represented by the following formula:
wherein R
1
is a hydrogen or halogen atom, —OCOR
3
, an alkyl or alkoxy group which may be substituted, where R
3
is an alkyl or phenyl group which may be substituted; x denotes an integer of from 1 to 3; each of Q
1
to Q
8
independently a hydrogen atom, an alkyl group or a phenyl group; and each of Z
1
to Z
3
is independently a divalent phenyl group or a divalent phenyl group substituted with an alkyl group or a hydroxyl group. The reference mentions that this positive resist composition is well-balanced in definition, profile, depth of focus and other properties.
However, the reference fails to describe the formation of mixed resist patterns including both dense patterns and isolation patterns and to describe a specific structure of a compound represented by Formula (I) mentioned below for use in the present invention.
In the formation of mixed resist patterns including both dense patterns and isolation patterns, demands are made on resist compositions that can form both dense patterns and isolation patterns with good shapes and can especially minimize the formation of a back taper shape of the isolation resist patterns induced by shift of the focus to the minus side.
Japanese Patent Application Laid-Open No. 9-110762 (Reference 2) discloses a positive photoresist composition containing, as a photosensitive ingredient, a quinonediazidosulfonyl ester of a compound represented by the following formula:
The reference mentions that this composition is a photosensitive resin composition having a high sensitivity, high definition, satisfactory profile, satisfactory focus latitude and less development scum (development residue) and is well balanced in resist properties.
However, the reference fails to describe the formation of mixed resist patterns including both dense patterns and isolation patterns. In the formation of mixed resist patterns including both dense patterns and isolation patterns, demands are made on resist compositions that can form both dense patterns and isolation patterns with good shapes and can especially minimize the formation of a back taper shape of the isolation resist patterns induced by shift of the focus to the minus side.
Japanese Patent Application Laid-Open No. 9-114093 (Reference 3) discloses a positive photoresist composition containing, as a photosensitive ingredient, a quinonediazidosulfonyl ester of a compound represented by the following formula:
wherein each of R
1
to R
16
is independently a hydrogen, a hydroxyl group, an alkyl having from 1 to 6 carbon atoms or a phenyl; each of Q
1
to Q
10
is independently a hydrogen, an alkyl having from 1 to 6 carbon atoms or a phenyl; and each of m and n independently denotes 0 or 1. The reference mentions that this composition is a photosensitive resin composition having a high sensitivity, high definition, satisfactory profile, satisfactory focus latitude, high heat resistance and less development scum (development residue) and is well balanced in resist properties.
However, the reference fails to describe the formation of mixed resist patterns including both dense patterns and isolation patterns and to describe a specific structure of a compound represented by Formula (I) mentioned below for use in the present invention.
In the formation of mixed resist patterns including both dense patterns and isolation patterns, demands are made on resist compositions that can form both dense patterns and isolation patterns with good shapes and can minimize the formation of a back taper shape of the isolation resist patterns induced by shift of the focus to the minus side.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a positive photoresist composition for use in the formation of an ultrafine resist pattern of not more than half a micrometer, particularly of not more than 0.35 &mgr;m. This positive photoresist composition should have a satisfactory sensitivity, definition and DOF properties, can concurrently form a dense pattern and an isolation patter both with good shapes in the formation of a mixture of these resist patterns. Specifically, this positive photoresist composition could minimize the formation of a back taper shape of an isolation resist pattern induced by shift of the focus to the minus side.
After intensive investigations to achieve the above objects, the present inventors have accomplished the present invention.
Specifically, the present invention provides a positive photoresist composition including (A) an alkali-soluble resin and (B) a photosensitive ingredient, in which the photosensitive ingredient (B) includes an ester of a compound represented by following Formula (I) with a 1,2-naphthoquinonediazidosulfonyl compound:
The
Hidesaka Shinichi
Sawano Atsushi
Chu John S.
Sughrue & Mion, PLLC
Tokyo Ohka Kogyo Co. Ltd.
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