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
2000-03-28
2001-05-08
Le, Hoa Van (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
C430S311000, C430S286100, C430S281100
Reexamination Certificate
active
06228558
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a chemically amplified resist comprising a base resin and a photoacid generator and, more particularly, to a far-ultraviolet resist which provides excellent adhesion to Si substrates, improved resistance to dragging and placement after exposure, and improved pattern shapes.
2. Description of the Related Art
Conventional far-ultraviolet resists comprising a base resin and a photoacid generator include, as said base resin, a resin (t-butyl protective poly-carboxyl nor-bornane) with a cyclic carbonate employed, high in transparency to the far ultraviolet radiation, excellent in resistance to etching, and captured in the principal chain to allow a carbon atom—carbon atom bond as shown by formula (1) below.
In addition, conventional far-ultraviolet resists comprising a base resin and a photoacid generator also include a resin (tetra-hydroxyl protective carboxy tetra-cyclo dodecyl-methacrylate) which is branched from the principal chain as shown by formula (2) below.
Conventional far-ultraviolet resists have mainly employed these resins.
However, the aforementioned conventional far-ultraviolet resists provide inferior adhesion to Si substrates and provide deformed patterns when employed in fine patterns or defocused. Moreover, some of these conventional far-ultraviolet resists cannot be developed with a 2.38% TMAH standard developer, presenting a problem in that the resists are used with difficulty in practice.
Furthermore, a conventional KrF (&lgr;=248 nm) resist that employs hydroxystyrene as the base resin and is comparatively good in resistance to etching cannot be used for lithography in which ArF (&lgr;=193 nm) or a far-ultraviolet radiation shorter in wavelength than that which is used, because of significant absorption thereof. Accordingly, a resist with an alicyclic group is now used, however, this resist provides significant hydrophobicity, thus leading to a drawback of inferior adhesion between the resist and the substrate. Moreover, introduction of a unit for improving the adhesion would cause the ratio of the alicyclic group to decrease and thus the resistance to etching to deteriorate, so that both adhesion and resistance to etching have conventionally been satisfied with difficulty at the same time.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a chemically amplified resist that provides excellent adhesion to Si substrates, improved resistance to dragging and placement after exposure, improved pattern shapes, and can be preferably employed as a far-ultraviolet resist.
The chemically amplified resist relating to the present invention, which comprises a base resin and photoacid generator, is characterized in that said base resin has transparency to far-ultraviolet radiation and comprises a resin having a cyclic carbonate with resistance to etching bonded thereto by an amid bond.
The chemically amplified resist of the present invention includes polar groups of a carbonyl group and an amino group, and thus provides excellent adhesion to Si substrates having a high-polarity silanol group on the surface thereof. In addition, the amino group in the resin structure captures acids generated by exposure to prohibit the diffusion of the acids, thereby also improving resistance to dragging and placement after exposure and improving pattern shapes.
The resins used as a base resin in the present invention have a cyclic carbonate bonded by an amid bond, which is highly transparent to the far-ultraviolet radiation and excellent in resistance to etching. These resins are preferably, for example, t-butyl protective poly(2,5-p-carboxy nor-bornane amide) shown by formula (3) below, t-butyl protective poly(p-carboxy amino-cyclohexane amide) shown by formula (4) below, and t-butyl protective poly(2,5-carboxy amino-adamantane amide) shown by formula (5) below.
The chemically amplified resist of the present invention includes polar groups of a carbonyl group and an amino group, and thus provides excellent adhesion to Si substrates having a high-polarity silanol group on the surface thereof. In addition, the amino group in the resin structure captures acids generated by exposure to prohibit the diffusion of the acids, thereby also improving resistance to dragging and placement after exposure and improving pattern shapes.
REFERENCES:
patent: 5759739 (1998-06-01), Takemura et al.
patent: 5942367 (1999-08-01), Watanabe et al.
patent: 6106993 (2000-08-01), Watanabe et al.
patent: 6106995 (2000-08-01), Dixit et al.
patent: 6143466 (2000-11-01), Choi
patent: 9-73173 (1997-03-01), None
patent: 10-10738 (1998-01-01), None
patent: 10-204125 (1998-08-01), None
patent: 10-306120 (1998-11-01), None
Le Hoa Van
NEC Corporation
Walke Amanda C.
Young & Thompson
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