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
2001-02-05
2002-04-23
Chu, John S. (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
C430S905000, C430S919000
Reexamination Certificate
active
06376152
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photosensitive composition for use in the production of a lithographic printing plate, a semiconductor such as IC, a circuit board for liquid crystal and thermal head and in other photofabrication processes. More specifically, the present invention relates to a positive photosensitive composition which is reactive to a radiation of high energy such as a far ultraviolet ray (including an excimer laser beam), an electron beam, an X-ray or the like and suitably used for the production of semiconductor integrated circuit.
BACKGROUND OF THE INVENTION
Hitherto, in the process for the production of semiconductor device such as IC or LSI, fine fabrication of lithography employing a photoresist composition has been conducted. Keeping step with the recent high integration degree of integrated circuits, the formation of ultrafine patterns in a range of submicrons to a quarter micron have been required. In order to meet such a requirement, a wavelength for exposure tends to become shorter, for example, from a g-line to an i-line and further to a KrF excimer laser beam. Nowadays, lithography using the excimer laser beam is the important fabrication technique in the field of art and as a resist suitable for the excimer laser lithographic process, a chemical amplification-type resist is employed.
The chemical amplification-type resist composition is a pattern formation material which generates an acid in an exposed area upon irradiation with a radiation such as a far ultraviolet ray and due to a reaction using the acid as a catalyst, solubility in a developing solution differentiates in the area irradiated with the active radiation from the non-irradiated area to form a pattern on a substrate. The chemical amplification-type resist has high sensitivity and resolution and also has an advantage in that an image can be formed by a compound which generates an acid (hereinafter also referred to as a “photo-acid generator” sometimes) upon irradiation with a small amount of radiation.
Examples of the chemical amplification-type positive photoresist composition include combinations of a compound capable of generating an acid by photolysis with an acetal or O,N-acetal compound as described in JP-A-48-89003 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), with an ortho ester or amide acetal compound as described in JP-A-51-120714, with a polymer having an acetal or ketal group on the main chain as described in JP-A-53-133429, with an enol ether compound as described in JP-A-55-12995, with an N-acyliminocarbonic acid compound as described in JP-A-55-126236, with a polymer having an ortho ester group on the main chain as described in JP-A-56-17345, with a tertiary alkyl ester compound as described in JP-A-60-3625, with a silyl ester compound as described in JP-A-60-10247 or with a silyl ether compound as described in JP-A-60-37549 and JP-A-60-121446.
A system which is stable at a room temperature but decomposes by heating in the presence of an acid to become alkali-soluble is also known and examples thereof include combinations of a compound capable of generating an acid on exposure with an ester or carbonic acid ester compound having a tertiary or secondary carbon (e.g., tert-butyl or 2-cyclohexenyl) as described, for example, in JP-A-59-45439, JP-A-60-3625, JP-A-62-229242, JP-A-63-27829, JP-A-63-36240, JP-A-63-250642,
Polym. Eng. Sce.,
Vol. 23, page 1012 (1983),
ACS. Sym.,
Vol. 242, page 11 (1984),
Semiconductor World,
November, 1987, page 91,
Macromolecules,
Vol. 21, page 1475 (1988), and
SPIE,
Vol. 920, page 42 (1988) Since such a system has high sensitivity and a little absorption in a far ultraviolet region, it is suitable for ultrafine fabrication using a light source having a shorter wavelength.
In general, the chemical amplification-type positive photoresist composition is roughly divided into three types. Specifically, there are (1) a chemical amplification-type positive photoresist of three-component type comprising an alkali-soluble resin, a photo-acid generator and a dissolution-inhibiting compound having an acid-decomposable group for the alkali-soluble resin, (2) a chemical amplification-type positive photoresist of two-component type comprising a resin having a group capable of being decomposed by a reaction with an acid to become alkali-soluble and a photo-acid generator and (3) a chemical amplification-type positive photoresist of hybrid type comprising a resin having a group capable of being decomposed by a reaction with an acid to become alkali-soluble, a low molecular weight dissolution-inhibiting compound having an acid-decomposable group and a photo-acid generator. Any of the two-component, three-component and hybrid chemical amplification-type positive photoresist compositions is subjected to exposure to generate an acid from the photo-acid generator, heat treatment and development thereby obtaining a resist pattern.
In the lithography using a chemical amplification-type photoresist composition, a photoresist which is excellent in various characteristics, for example, sensitivity, resolution, profile, coating aptitude, heat resistance, dry etching resistance, adhesion, substrate reliance, environment stability (e.g., dimension stability of the resist against fluctuation in a period of storage after the pattern exposure) and depth of focus (e.g., pattern-forming ability against defocusing at the irradiation with a radiation) is desired. Thus, various investigations for improving these characteristics utilizing additives has been made.
For instance, an attempt has been made to add an acid-scavenger to the chemical amplification-type photoresist to prevent the acid generated from diffusion, thereby improving the resist characteristics, particularly the environment stability based on the specific reaction mechanism thereof. Specifically, the addition of organic amine is proposed as described, for example, in JP-A-5-127369, JP-A-5-232706, JP-A-5-249662, JP-A-5-289322, JP-A-6-317902, JP-A-7-92678 and JP-A-7-120929. Although the addition of organic amine is effective for improving resolution, it causes a problem of decreasing sensitivity.
Also, for the purpose of increasing sensitivity or improving profile of resist pattern, many attempts have been made to add various compounds to the chemical amplification-type photoresist. For example, the addition of carboxylic acid is described, for example, in JP-A-5-181279, JP-A-7-92679, JP-A-9-6001, JP-A-9-6002, JP-A-9-6003, U.S. Pat. Nos. 5,955,240 and 5,948,589 and European Patent 679,951. The addition of aromatic polyhydroxy compound is described, for example, in JP-A-4-134345, JP-A-4-217251, JP-A-7-181680, JP-A-8-211597 and U.S. Pat. Nos. 5,688,628 and 5,972,559. The addition of sulfonamide compound is described, for example, in JP-A-5-181263 and JP-A-7-92680.
Further, the investigations for improving the resist characteristics such as resolution, exposure latitude, adhesion and substrate reliance have been made. For example, a method for preventing pattern failure by adding formamide or acetamide is proposed as described in JP-A-9-5987,U.S. Pat. No. 5,770,343 and European Patent 749,044. A method for improving substrate reliance by adding a nitrogen-containing compound such as succinimide or phthalimide is proposed as described in JP-A-11-44950. A method for improving environment stability (e.g., dimension stability of the resist against fluctuation in a period of storage after the pattern exposure), resolution and depth of focus by adding a compound which decreases its basicity upon exposure (photo-base) as described in JP-A-5-232706, JP-A-6-11835, JP-A-6-242606, JP-A-6-266100, JP-A-7-333851, JP-A-7-333844, U.S. Pat. No. 5,663,035 and European Patent 677,788.
Moreover, a method for improving resolution and depth of focus by adding a specific low molecular weight acid-decomposable dissolution-inhibiting compound to a two-component chemical amplification-type photoresist as described in JP-A-9-297396.
With photoresist com
Kanna Shinichi
Kawabe Yasumasa
Nishiyama Fumiyuki
Chu John S.
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
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