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
2000-05-25
2002-11-12
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
Reexamination Certificate
active
06479211
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition for use in the ultramicro-lithography process and other photofabrication processes, such as production of ultra-LSI and high-capacitance micro-chip. More specifically, the present invention relates to a positive photoresist composition for far ultraviolet exposure, which can form a highly precise pattern using light in the far ultraviolet region including an excimer laser ray, particularly, in the region of 250 nm or less.
BACKGROUND OF THE INVENTION
In recent years, the integration degree of integrated circuits Is more and more elevated and in the production of a semiconductor substrate such as ultra-LSI, an ultrafine pattern consisting of lines having a width of half micron or less must be worked. To meet this requirement, the wavelength used in the exposure apparatus for photo-lithography increasingly becomes shorter and at the present time, studies are being made on the use of an excimer laser ray (e.g., XeCl, krF, ArF) having a short wavelength among far ultraviolet rays.
In the formation of a pattern for lithography using this wavelength region, a chemical amplification-system resist is used.
The chemical amplification-system resist in general can be roughly classified into three groups, that is, commonly called 2-component system, 2.5-component system and 3-component system. The 2-component system uses a combination of a compound capable of generating an acid by the photochemical decomposition (hereinafter referred to as a “photo-acid generator”) and a binder resin. This binder resin is a resin having within the molecule thereof a group capable of decomposing under the action of an acid and thereby increasing solubility of the resin in an alkali developer (also called acid-decomposable group). The 2.5-component system contains a low molecular compound having an acid-decomposable group in addition to the 2-component system. The 3-component system contains a photo-acid generator, an alkali-soluble resin and the above-described low molecular compound.
The chemical amplification-system resist is suitable as a photoresist for use under irradiation with an ultraviolet ray or a far ultraviolet ray but still in need of coping with the characteristics required for individual uses. or example, a resist composition using a polymer obtained by introducing an acetal or ketal group into a hydroxystyrene-base polymer reduced in the light absorption particularly in the case of using light at 248 nm of a KrF excimer laser has been proposed in JP-A-2-141636 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), JP-A-2-19847, JP-A-4-219757, JP-A-5-281745 and the like. In addition, a similar composition using a t-butoxycarbonyloxy or p-tetrahydropyranyloxy group as the acid-decomposable group has been proposed in JP-A-2-209977, JP-A-3-206458 and JP-A-2-19847.
These compositions are suitable for the case of using light at 248 nm of the KrF excimer laser, however, when an ArF excimer laser is used as the light source, the substantial absorbance is still excessively large and therefore, the sensitivity is low. Accompanying this, other defects such as deterioration in the resolution, the focus allowance or the pattern profile arise. Thus, improvements are necessary in many points.
As a photoresist composition for use with an ArF light source, a resin in which an alicyclic hydrocarbon site is introduced so as to impart dry etching resistance has been proposed. Examples of this resin include resins obtained by copolymerizing a monomer having a carboxylic acid site such as acrylic acid or methacrylic acid or a monomer having a hydroxyl group or a cyano group within the molecule, with a monomer having an alicyclic hydrocarbon group.
The alicyclic hydrocarbon site introduced into the photoresist composition for use with an ArF light source so as to impart dry etching resistance disadvantageously renders the system extremely hydrophobic, as a result, the resist may not be developed with an aqueous tetramethylammonium hydroxide (hereinafter referred to as “TMAH”) solution heretofore widely used as a developer for resists or there may arise a phenomenon such that the resist falls off from the substrate during the development.
With an attempt to overcome this hydrophobitization of the resist, an organic solvent such as isopropyl alcohol is mixed in the developer. This gains a certain result but still suffers from problems such as swelling of the resist film or the cumbersome process. From the standpoint of improving the resist, a large number of techniques have been proposed, for example, hydrophobitization ascribable to various alicyclic hydrocarbon sites is compensated for by introducing a hydrophilic group.
JP-A-10-10739 discloses an energy-sensitive resist material containing a polymer obtained by polymerizing a monomer having an alicyclic structure such as norbornene ring in the main chain, a maleic acid anhydride and a monomer having a carboxyl group. JP-A-10-111569 discloses a radiation-sensitive resin composition containing a resin having an alicyclic skeleton in the main chain and a radiation-sensitive acid generator. JP-A-11-109632 discloses use of a radiation-sensitive resin composition containing a polar group-containing alicyclic functional group and an acid-decomposable group.
In general, the problems related to the developability have been intended to overcome by copolymerizing a monomer having a carboxylic acid site such as acrylic acid or methacrylic acid or a monomer having a hydroxyl group or a cyano group within the molecule, with a monomer having an alicyclic hydrocarbon group. However, the results are not satisfied by any means.
Other than the above-described method of introducing an alicyclic hydrocarbon site into the side chain of an acrylate-base monomer, a method of using an alicyclic hydrocarbon site in the polymer main chain to impart dry etching resistance is also studied.
Furthermore, JP-A-9-73173, JP-A-9-90637 and JP-A-10-161313 describe a resist material using an acid-sensitive compound containing an alkali-soluble group protected by a structure containing an alicyclic group, and a structural unit for rendering the alkali-soluble group when released from the acid, to be alkali soluble.
JP-A-11-109632 describes use of a resin containing a polar group-containing alicyclic functional group and an acid-decomposable group, in a radiation-sensitive material.
On the other hand, JP-A-8-248561 discloses a photo-reactive composition comprising a photo-acid generator and an acid-increasing agent capable of generating a new acid by the acid generated from the photo-acid generator. In
SPTE
., vol. 3049, pp. 76-82, a chemical amplification-system resist for 193-nm lithography containing an acid generator, a partially protected alicyclic polymer and an acid-increasing agent is disclosed.
The resin having an acid-decomposable group, which is used in the photoresist for far ultraviolet exposure, generally contains an aliphatic cyclic hydrocarbon group within the molecule at the same time. Therefore, the resin becomes hydrophobic and there arise problems attributable to it. For overcoming the problems, various techniques have been aggressively investigated as described above, however, these techniques are insufficient in many points (particularly in the developability) and improvements are demanded.
That is, this technique of using a light source of emitting a far ultraviolet ray of short wavelength, for example, an ArF excimer laser (193 nm), as the exposure light source is still in need of improvements in view of the developability. To speak specifically, development failure may arise or scum (development residue) may be generated. Furthermore, the defocus latitude depended on line pitch is also in need of improvements. Devices in recent years have a tendency to contain various patterns, therefore, the resist is required to have various capabilities. One of these capabilities is the defocus latitude on line pitch. More specifically, a device has a portion w
Aoai Toshiaki
Kodama Kunihiko
Nakao Hajime
Sato Kenichiro
Chu John S.
Fuji Photo Film Co. , Ltd.
Sughrue & Mion, PLLC
LandOfFree
Positive photoresist composition for far ultraviolet exposure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Positive photoresist composition for far ultraviolet exposure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Positive photoresist composition for far ultraviolet exposure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2986200