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
2000-04-03
2004-09-21
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
C430S905000, C430S910000
Reexamination Certificate
active
06794108
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a positive photoresist composition for far ultraviolet exposure, which is used 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, working to provide an ultrafine pattern consisting of lines having a width of half micron or less is required. To meet this requirement, the wavelength used in the exposure apparatus for photolithography 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 a group capable of decomposing by 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 used under irradiation of an ultraviolet ray or a far ultraviolet ray but still in need of coping with the characteristics required for individual uses.
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. However, the alicyclic hydrocarbon site introduced disadvantageously renders the system to be extremely hydrophobic, and as a result, the resist can 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 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) 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-generating agent. JP-A-11-202491 discloses a radiation-sensitive resin composition containing a polymer having a norbornene derivative and an androstane-17-carboxylic acid ester compound.
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 still insufficient in many points (particularly in the developability) and in need of improvements.
On the other hand, JP-A-8-248561 discloses a photoreactive composition comprising a photo-acid generator and an acid-increasing agent capable of generating a new acid by the acid generated from the acid-generating agent. In
SPIE
., vol. 3049, pp. 76-82, a chemical amplification-system resist for 193-nm lithography containing an acid-generating agent, a partially protected alicyclic polymer and an acid-increasing agent is disclosed.
However, this technique 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 defect may arise or scum (development residue) may be generated. Furthermore, the line width fluctuates every each pattern formation and improvement are necessary also in the line width reproducibility.
The defocus latitude depended on line pitch is also in need of improvements. More specifically, a device has a portion where lines are crowded, a pattern where the space is broad as compared with lines, and isolated lines. Therefore, it is important to resolve various lines with high reproducibility. However, reproduction of various lines cannot be easily attained because of optical factors and the resist is not yet succeeded in undertaking the part of solving this problem at present. In particular, the above-described resist system containing an alicyclic group conspicuously varies in the reproducibility between the isolated pattern and the crowded pattern, and improvements are being demanded.
In addition, the storage stability of the resist solution is also in need of improvements. For example, when a chemical amplification-system photoresist is stored in the liquid state, due to the poor compatibility between the resin and the photo-acid generator, particles may be generated in the solution or the resist performance may be deteriorated (deterioration in the storage stability of the resist solution).
JP-A-10-254139 discloses a resin composition containing a solvent comprising a mixture of a resin having an acid-decomposable group and an alicyclic skeleton, a radiation-sensitive acid-generating agent and at least one selected from the group consisting of linear ketone, cyclic ketone, propylene glycol monoalkyl ether acetate and alkyl 2-hydroxypropionate. This system also has the above-described problem of poor storage stability and studies are being made by the similar approach.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to attain technical improvements in the capability inherent in the microphotofabrication using a far ultraviolet ray, particularly an ArF excimer laser ray.
More specifically, a first object of the present invention is to provide a positive photoresist composition free from the generation of development defect and scum at the development, and a positive photoresist composition for far ultraviolet exposure, having excellent line width reproducibility.
A second object of the present invention is to provide a positive photoresist composition excellent in the sensitivity, resolution, dry etching resistance and adhesion to the substrate, and free from the generation of development defect and scum at the development and a positive photoresist composition for far ultraviolet exposure, having excellent defocus latitude depended on line pitch.
A third object of the present invention
Adegawa Yutaka
Aoai Toshiaki
Kodama Kunihiko
Sato Kenichiro
Ashton Rosemary
Fuji Photo Film Co. , Ltd.
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-3272883