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
2000-07-20
2004-09-07
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, C430S910000
Reexamination Certificate
active
06787283
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition for use in the ultramicrolithography process and other photofabrication processes, such as production of VLSI (Very Large Scale Integration) and high-capacitance micro-chip. More specifically, the present invention relates to a positive photoresist composition capable of forming 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 VLSI, 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 weight 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 weight 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 on use. For example, a resist composition using a polymer obtained by introducing an acetal or ketal protective group into a hydroxystyrene-base polymer which exhibits small light absorption particularly for 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 problems arise, such as deterioration in the resolution, the focus allowance or the pattern profile. 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.
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 being 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 allowing the alkali-soluble group to be released under the action of an acid and render the compound alkali-soluble.
In addition, a resin obtained by introducing a hydrophilic 5- or 6-membered ring lactone group into the above-described resin having an alicyclic group so as to improve the affinity for an alkali developer or the adhesion to a substrate is described in JP-A-9-90637, JP-A-10-207069, JP-A-10-274852 and JP-A-10-239846.
However, these techniques are insufficient in many points such as improvement for higher sensitivity and higher resolution or improvement of the adhesive property to a substrate, and they are still in need of improvements.
Also, in recent years, to cope with the requirement for semiconductor chips in a finer size, the design pattern for the fine semiconductor has reached to a region as fine as 0.13 to 0.35 &mgr;m. The above-described compositions have, however, a problem in that the resolution of the pattern is inhibited due to the factors such as edge roughness of the line pattern or the like. The term “edge roughness” as used herein means the fact that due to the properties of the resist, the edges at the top and bottom of a resist line pattern irregularly fluctuate in the direction perpendicular to the line direction and unevenness is observed on the edges when viewed from right above.
With respect to the 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. However, the system disadvantageously becomes extremely hydrophobic due to the alicyclic hydrocarbon site introduced, as a result, the resist may not be developed with an aqueous tetramethylammonium hydroxide (hereinafter referred to as “TMAH”) solution which has been 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, the 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 resin containing a polar group-containing alicyclic functional group and an acid-decomposable group, for a radiation-sensitive material.
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, the technique of using a light source of emitting a far ultraviolet ray of short wavelength, for example, an ArF excimer laser (193 nm) is still in need of improvements in view of the developability. To speak specifically, the problem is the de
Aoai Toshiaki
Kodama Kunihiko
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-3268050