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
2000-12-18
2003-03-04
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
C430S296000, C430S905000
Reexamination Certificate
active
06528233
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a negative-working resist composition suitably used for a super micro lithographic process for producing VLSI and high-capacity microchips and other photofabrication processes. More specifically, the invention relates to a negative-working photoresist composition capable of forming highly fined patterns using X-rays, electron beams, etc., including an excimer laser light and particularly to a negative-working resist composition suitably used for very fine working of semiconductor devices using high energy rays such as electron beams, X-rays, etc.
BACKGROUND OF THE INVENTION
The integration degree of integration circuits has been more and more increased and in the production of a semiconductor substrate such as VLSI, etc., working of very fine patterns made of line width of a half micron or finer has become required. For satisfying the requirement, the using wavelength of a light exposure apparatus used for a photolithography becomes shorter and shorter and at present the use of a far-ultraviolet light and an excimer laser light (XeCl, KrF, ArF, etc.) has been investigated. Furthermore, the formation of finer patters by electron beams or X-rays has been investigated.
Particularly, electron beams or X-rays are positioned as the pattern forming technique of the next generation or further and the development of a negative-working resist capable of attaining a high-sensitive, high-resolving, and rectangular profile form has been desired.
In an electron ray lithography, a resist material is light-exposed to an energy released in the stage that accelerated electron beams are collided with the atoms constituting the resist material and cause scattering. By using highly accelerated electron beams, the straight-going property is increased, the influence of electron scattering is reduced, and the formation of patterns of a high-resolution and a rectangular form becomes possible but on the other hand, the permeability of electron beams is increased and the sensitivity is lowered. As described above, in the electron ray lithography, the sensitivity and the resolution•resist pattern are in the relation of trade off, and it was a problem to obtain both the properties together.
Also, an X-ray lithography has the same problem as above.
Hitherto, for chemical amplification type negative-working resist, various alkali-soluble resins have been proposed. For example, JP-A-8-152717 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses partially alkyletherificated polyvinyl phenol, JP-A-6-67431 and JP-A-10-10733 disclose a copolymer of vinyl phenol and styrene, Japanese Patent 2505033 discloses a novolac resin, and JP-A-7-311463 and JP-A-8-292559 disclose monodispersed polyvinyl phenol, but by these alkali-soluble resins, both the characteristics of the sensitivity and the resolution•resist pattern are not obtained together under the irradiation of electron beams or X-rays.
Also, hitherto, for the chemical amplification type negative-working resist, various compounds generating an acid by electron beams or X-rays are proposed. For example, JP-B-8-3635 (the term “JP-B” as used herein means an “examined Japanese patent publication”) discloses organic halogen compounds, JP-A-2-150848 and JP-A-6-199770 disclose iodonium salts and sulfonium salts, JP-A-2-52348, JP-A-4-367864, and JP-A-4-367865 disclose acid-generating agents containing Cl or Br, JP-A-4-210960 and JP-A-4-217249 disclose diazodisulfone compounds and diazosulfone compounds, JP-A-4-226454 discloses triazine compounds, and JP-A-3-87746, JP-A-4-291259, and JP-A-6-236024 and U.S. Pat. No. 5,344,742 disclose sulfonate compounds, but by these acid-generating agents, the trade off of the sensitivity and the resolution•resist pattern under the irradiation of electron beams or X-rays could not be overcome.
Furthermore, about a crosslinking agent, methylolmelamine, resole resins, epoxydated novolac resins, urea resins, etc., have hitherto been used, but these crosslinking agents are unstable to heat, there is a problem in the storage stability in the case of forming a resist liquid, and further they cannot satisfy the required characteristics of the sensitivity and high-resolution and rectangular resist pattern under the irradiation of electron beams or X-rays.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made for solving the problems on the technique of improving the performance essential to the microfabrication using electron beams or X-rays and provides a negative-working chemical amplification type resist composition for electron beams or X-rays satisfying the characteristics of the sensitivity and the resolution•resist pattern for the use of electron beams or X-rays.
The problem described above has been attained by the following invention.
1. A chemical amplification type negative-working resist composition for electron beams or X-rays comprising
(1) an alkali-soluble resin having a weight-average molecular weight of exceeding 3,000 and not larger than 1,000,000.
(2) a crosslinking agent causing crosslinkage with an acid, and
(3) a compound generating an acid by the irradiation of electron beams or X-rays, wherein
the alkali-soluble resin satisfies following conditions (a) and (b);
(a) the resin has at least one repeating unit induced from a monomer having an aromatic ring having 6 or more and 20 or less carbon atoms and an ethylenically unsaturated group bonded to the aromatic ring directly or via a linkage group, and
(b) between the &pgr; electrons of the aromatic ring and the number of electrons of the unshared electron pair of a substituent on the aromatic ring, the following relation exists;
N&pgr;+½N
lone
≧10 (Equation 1)
wherein N&pgr; represents a total number of &pgr; electrons and N
lone
represents a total number of electrons of the unshared electric pair of a straight chain, branched, or cyclic alkoxy group, alkenyloxy group, aryloxy group, or aralkyloxy group having from 1 to 12 carbon atoms, or a hydroxyl group as the substituent, and adjacent two groups of two or more alkoxy groups or hydroxyl groups may combine with each other to form a ring structure of a 5-membered or higher-membered ring.
2. The chemical amplification type negative-working resist composition for electron beams or X-rays described in the above-described item 1, wherein the alkali-soluble resin has at least one repeating unit represented by the following formulae (1) to (5) as the constituting component;
wherein, R
101
represents a hydrogen atom or a methyl group; L represents a divalent linkage group; Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, Ri, Rj, Rk, and Rl each independently represents a straight chain, branched, or cyclic alkyl group, alkcenyl group, aryl group, or aralkyl group having from 1 to 12 carbon atoms, or a hydrogen atom, also they may combine with each other to form a ring of 5 members or higher having not more than 24 carbon atoms; l, m, n, p, q, r, s, t, u, v, w, and x each represents an integer of from 0 to 3, and satisfy l+m+n=2 or 3, p+q+r=0, 1, 2, or 3, s+t+u=0, 1, 2, or 3, and v+w+x=0, 1, 2, or 3.
3. The chemical amplification type negative-working resist composition for electron beams or X-rays described in the above-described item 1 or 2, wherein the crosslinking agent causing crosslinkage with an acid is a phenol derivative having from 1 to 6 benzene rings in the molecule, has a molecular weight of not larger than 1500, and has at least two hydroxymethyl groups and/or alkoxymethyl groups in the whole molecule, which is bonded to at least one of benzene ring atomic groups.
4. The chemical amplification type negative-working resist composition for electron beams or X-rays described in any one of the above-described items 1 to 3, wherein the molecular weight distribution of the alkali-soluble resin is from 1.0 to 1.5.
5. The chemical amplification type negative-working resist composition for electron beam
Ashton Rosemary
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
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