Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Forming nonplanar surface
Reexamination Certificate
2000-04-26
2002-07-09
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Forming nonplanar surface
C430S281100, C430S302000, C430S288100, C430S914000, C430S944000
Reexamination Certificate
active
06416939
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a negative type image recording material that can be used as a printing plate for lithographic printing and as a photoresist. In particular, the present invention relates to a negative type image recording material that is ideal for use as a printing plate for lithographic printing enabling so-called direct plate making, in which direct plate making from digital signals supplied from a computer or the like can be achieved using lasers of various types.
2. Description of the Related Art
Solid state lasers, semiconductor lasers, and gas lasers that are capable of emitting UV light, visible light and infra-red light of wavelengths from 300 nm to 1200 nm which are of high output and small size have become easily obtainable; such lasers are extremely useful as recording light sources in direct plate making from digital data supplied by a computer, for example. Various types of recording material that respond to these various types of laser light are being studied.
Firstly, as a material that is capable of recording using an infra-red laser of photosensitive wavelength 760 nm or more, Japanese Patent Application Laid-Open (JP-A) No. 10-203037 discloses an image recording material comprising a polymer having a heterocyclic group, a cross-linking agent, acid generating agent, and infra-red absorbent. Although the sensitivity and stability over time of this image recording material have been somewhat improved, further improvement of its performance is desired.
Secondly, as recording materials capable of responding to laser light of short wavelength or visible laser light of 300 nm~700 nm, most attention has been attracted by recording materials of the radical polymerization type, and various types of these are being studied. However, since, with recording materials of the radical polymerization type, radical polymerization is employed as the image forming mechanism, it is necessary to prevent interference with the progress of radical polymerization by cutting off oxygen from the sensitive material. A method of reducing interference of oxygen with polymerization and achieving higher sensitivity of the sensitive material is to provide an oxygen-impermeable oxygen cut-off layer at the surface of the sensitive material; for this oxygen cut-off layer, usually, polyvinyl alcohol etc. is employed. However, from the point of view of ease of handling in the developing step etc. after plate making, as well as reproducibility of the image, it is preferable not to provide such an oxygen cut-off layer.
Thirdly, regarding photoresist material of the electron beam-responsive type, in recent years research is being prosecuted vigorously, against the background of for example an increasing degree of integration of integrated circuits and even in semiconductor substrate manufacture for VLSI chips etc., where it is becoming necessary to process very fine patterns of lead width under half a &mgr;m. In order to satisfy this requirement, the wavelengths employed in the exposure devices used in photolithography are being made increasingly shorter, far UV light or excimer or laser light (XeCl, KrF, ArF etc.) is being studied, and the formation of very fine patterns by electron beams is also being studied. In particular, electron beams are positioned [to fulfill the role of] light sources in next-generation or post-next generation pattern-forming technology, so the development is desired of negative type photoresist materials, which are highly sensitive to electron beams and whereby there can be achieved a fine high-resolution pattern having a rectangular profile.
In electron-beam lithography, the photoresist material is photosensitized by emission of energy in a step in which an accelerated electron beam causes collision scattering with the atoms constituting the photoresist material. If an electron beam is employed that has been subjected to a high degree of acceleration, its linearity is increased and the effects of electron scattering are reduced. As a result, a pattern of rectangular shape can be formed with high resolution. On the other hand, high acceleration causes the problem that transmissivity of the electron beam is increased, reducing sensitivity. Thus, in electron beam lithography, sensitivity and resolution and/or storage stability are in a trade-off relationship and the problem is to achieve both of these at the same time.
The present situation regarding recording materials that are responsive to laser light of various types is that a fully satisfactory product has not yet been obtained. Methods of image recording involving an acid-catalyzed cross-linking system, in particular, utilizing cationic polymerization, continue to attract attention as methods of image recording capable of solving the problems referred to above. Regarding image recording materials utilizing cationic polymerization, photosensitive compositions employing an iodonium salt and cationic polymerizable compound are proposed in for example JP-A No. 3-68950 and U.S. Pat. No. 4,264,703. Also, JP-A No. 59-147001 and U.S. Pat. No. 4,442,197 propose photo-hardening compositions using a sulfonium salt and a cationic polymerizable epoxy compound or vinyl ether compound. Furthermore, JP-A No. 59-180543 proposes a photosensitive composition using an oxysilane, oxetane, thiirane, or thietane ring-containing compound, while JP-A No. 2-43202 proposes a hardenable composition etc. using a pyridinium salt as initiator. However, none of these image recording materials show sufficient stability over time.
An object of the present invention is to solve the above problem. Specifically, an object thereof is to provide a negative type image recording material whereby an image can be directly recorded from digital data supplied by for example a computer, by recording using a short-wavelength laser, visible laser, solid-state laser or semiconductor laser that emits infra-red rays, gas laser or electron beam. A further object is to provide a negative type image recording material that shows excellent sensitivity when employed as a printing plate, high resistance to printing when employed in printing, and has excellent storage stability. Yet a further object is to provide a negative type image recording material that shows high sensitivity when used as a photoresist material and also excellent resolution and storage stability.
SUMMARY OF THE INVENTION
As a result of intensive study of negative type image recording materials, the present inventors discovered that the foregoing problems could be solved by employing, together with a compound having a specific styrene group, as a binder, a polymer capable of bonding with the styrene group in the presence of acid, and thereby succeeded in perfecting the present invention.
Specifically, the present invention provides in a negative type image recording material containing (A) a compound having at least one group represented by general formula (1) below, (B) a polymer capable of reacting with compound (A) in the presence of acid, and (C) a compound that generates acid in response to energetic radiation, an electron beam, or heat.
In general formula (1) Ar
1
represents an arylene group, and R
1
represents a hydrogen atom or an alkyl group of carbon number 1~6.
The negative type image recording material according to the present invention is characterized by using as cross-linking agent a compound having at least one group represented by general formula (1) above. Catalytically, in the presence of a small quantity of acid, this styrene group performs a cross-linking reaction with the binder constituted by polymer (B); it is believed that, as a result of this cross-linkage of the binder, benzene rings etc., which are hydrophobic groups, are inserted into the binder, increasing the hydrophobic character of the exposure region, and increasing resistance to printing and resolution. Also, it is believed that, since these styrene groups are cationically polymerizable, such styrene groups polymerize under acid catalysi
Kunita Kazuto
Shimada Kazuto
Ashton Rosemary
Fuji Photo Film Co. , Ltd.
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