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
2001-06-14
2004-02-24
Hamilton, Cynthia (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
Reexamination Certificate
active
06696219
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive resist laminate suitable for exposure to a radiant ray such as an ultraviolet ray, a far ultraviolet ray, an X-ray, an electron beam, a molecular beam, a &ggr;-ray and a synchrotron radiation. More particularly, it relates to a positive resist laminate for use in the fine fabrication which is employed in a step for producing a circuit board in production of a semiconductor such as integrated circuit and which has particularly high resolution and sensitivity, provides a resist having rectangular cross-sectional form and possesses wide process allowance.
The positive resist laminate of the present invention can be used in the following manner. For instance, the positive resist laminate is formed on a substrate such as a semiconductor wafer, glass, ceramic and metal, or an anti-reflective layer or organic layer provided thereon by a spin coating method or a roller coating method in a thickness of from 0.01 to 3 &mgr;m. Then, it is heated, dried, printed a circuit pattern through an exposure mask by irradiation with an active ray and developed to form a positive image. Thereafter, etching is conducted using the positive image as a mask, thereby performing pattern fabrication on the substrate. Typical application field of the resist laminate of the present invention includes production of semiconductor such as integrated circuit, production of circuit board for liquid crystal or thermal head and other photofabrication processes.
BACKGROUND OF THE INVENTION
Keeping step with increased integration of LSI, resolution limit becomes clear in a monolayer resist hitherto known. Thus, there has been proposed a method for forming a high figure-ratio pattern which is fine and has a large thickness using a multilayer resist instead of the monolayer resist. Specifically, a thick organic polymer layer is formed as a first layer and a thin resist material layer is then formed thereon as a second layer. The resist material of the second layer is exposed to high energy radiation and developed. Using the pattern thus-formed as a mask the organic polymer of the first layer is anisotropically etched by oxygen plasma etching (O
2
RIE), thereby providing a pattern having a highly rectangular form (refer to
Solid State Technology,
vol. 24, page 73 (1981)).
In such a case, since the second resist layer must have high resistance to the O
2
RIE, a silicon-containing polymer is conventionally used. In particular, a polymer of vinyl polymerization type having a silicon atom in the side-chain thereof is widely investigated because of impartation of heat resistance and ease of synthesis, as described, for example, in JP-A-2-293850 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), JP-A-10-282678 and U.S. Pat. No. 5,856,071.
The first resist layer is ordinarily formed by a method of setting a novolak resin with heat temperature treatment in order to provide good adhesion to a substrate, a good film-forming property, high dry-etching resistance, immiscibility with the second resist layer, a large light-absorbing property in the exposure wavelength range and the like, and the method is widely employed. However, since adhesion of such a layer to the second resist layer comprising the silicon-containing polymer is poor, the method has a problem in that winding of line and further break of pattern tend to occur, particularly in fine line/space of 0.2 &mgr;m or less.
Further, it is necessary for the first resist layer containing the novolak resin to be subjected to the high temperature treatment for a long period of time. This causes a problem in that production aptitude is very low in the production of semiconductor device. If the high temperature treatment is conducted in a short time, setting of the first resist layer becomes insufficient to cause a phenomenon of mixing with the second resist layer (intermix) and as a result, a pattern having a large amount of development residue is formed.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a positive resist laminate having high resolution which is respondent to exposure in a far ultraviolet region.
Another object of the present invention is to provide a positive resist laminate which provides a resist pattern in which winding of line is restrained in fine line/space of 0.2 &mgr;m or less.
A further object of the present invention is to provide a positive resist laminate which depresses an amount of development residue (development defect) occurred in fine line/space of 0.2 &mgr;m or less.
A still further object of the present invention is to provide a positive resist laminate which has high production aptitude.
Other objects of the present invention will become apparent from the following description.
As a result of intensive investigations made by the inventors taking the above-described problems into consideration, it has been found that the objects of the present invention are accomplished by the following positive resist laminates:
(1) A positive resist laminate which comprises a substrate, a first resist layer and a second resist layer, in this order,
wherein the first resist layer is to be hardened with heat and comprises (a-1) a polymer containing a repeating unit represented by formula (1) shown below and a repeating unit represented by formula (2) shown below, and
the second resist layer comprises: (b) a polymer which contains a silicon atom in the side chain thereof and which is insoluble in water and becomes soluble in an aqueous alkali solution by the action of an acid; and (c) a compound which generates an acid upon irradiation with an actinic ray or radiation:
wherein Y
1
and Y
2
each independently represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom; L
1
and L
2
each independently represents a divalent linkage group which may be substituted; J represents an alicyclic hydrocarbon group which may be substituted; a1 represents 0 or 1; K represents an aryl group which may be substituted; and a2 and a3, which are the same or different, each represents 0 or 1.
(2) The positive resist laminate as described in item (1), wherein the polymer (a-1) contains at least one group selected from a hydroxy group, a primary amino group and a secondary amino group, and
the first resist layer further comprises: (a-2) a crosslinking agent which is activated by an acid to react with the polymer (a-1), thereby forming a crosslinking structure; and (a-3) a compound which generate an acid by heat.
(3) The positive resist laminate as described in item (1), wherein the polymer (b) is at least one of:
a polymer (b-1) contains: a repeating unit represented by formula (4) shown below; and at least one repeating unit selected from those represented by formulae (5a) and (5b) shown below; and
a polymer (b-2) contains: a repeating unit represented by formula (4) shown below; at least one repeating unit selected from those represented by formulae (5a) and (5b) shown below; and a repeating unit represented by formula (6) shown below:
wherein Y
4
represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom; R
2
, R
3
and R
4
, which are the same or different, each represents an alkyl group, a haloalkyl group, a halogen atom, an alkoxy group, a trialkylsilyl group or trialkylsilyloxy group; L represents an alkylene group which may be substituted; and n represents 0 or 1,
wherein Y
5
represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom; L
3
represents a mere bond or a divalent linkage group; and Q represents a group which is decomposable by an acid to generate a carboxylic acid,
wherein X
1
and X
2
, which are the same or different, each represents an oxygen atom, a sulfur atom, —NH— or —NHSO
2
—; L
11
and L
12
, which are the same or different, each represents a mere bond or a divalent linkage group; A
1
and A
2
, which are the same or different, each represents a hydrogen atom, a cyano group, a hydroxy group, —COOH, —COOR
5
, —CO—NH-R
6
, an
Sato Kenichiro
Yasunami Shoichiro
Fuji Photo Film Co. , Ltd.
Hamilton Cynthia
Sughrue & Mion, PLLC
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