Title of Invention

NEGATIVE PHOTORESIST COMPOSITION

Abstract

This invention provides a negative photoresist composition and in particular, it provides a negative photoresist composition comprising a poly (2-ethyl-2-oxazoline), an azide-based photosensitizer and a pure water. The negative photoresist compositions of the invention can prevent environmental hazard, replacing photoresists to which Cr is applied when they are applied to B/M manufacturing process for CRT, shadow mask manufacturing process, etc., and they can increase sensitivity by the suitable selection of light by light absorption bands pursuant to processing conditions when exposed to light so that DOT/STRIPE photoresist membranes having excellent adhesion and resolution can be obtained.

Full Text

FORM 2 THE PATENT ACT 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10 and rule 13) 1. Negative Photoresist Composition 2. (A) DONGJIN SEMICHEM Co., Ltd. (President: Mr. Boo-Sup Lee) (B) UNITED STATES OF AMERICA (C) A Korean Corporation (Manufacturers and Merchants) 472-2, Gajwa-Dong, Seo-Gu, Incheon, 404-205, Republic of Korea The following specification particularly describes the invention and the manner in which it is to be performed. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a negative photoresist composition and more particularly, it relates to a negative photoresist composition capable of preventing environmental hazard of Cr and increasing sensitivity by the suitable selection of light by light absorption bands pursuant to processing conditions when exposed to light and at the same time, striving for quality upgrade by enabling the production of DOT/STRIPE photoresist membranes having excellent adhesion and resolution when applied to B/M manufacturing process for CRT, shadow mask manufacturing process, etc. In prior arts, as photoresist compositions, there have been mostly used photoresist compositions using polyvinyl alcohols (PVA) or caseins and sodium dichromate (SDC), ammonium dichromate (ADC), etc. as a photosensitizer and photoresist compositions using polyvinyl pyrrolidones or poly acrylamide diacetoneacrylamides (PAD) and an azide-based photosensitizer. However, as the above photoresist compositions have low adhesion and resolution when applied to B/M manufacturing process for CRT and shadow mask manufacturing process, they need remedy. Meanwhile, the photoresist composition, which is a mixture solution where ^polyvinyl alcohol and photosensitizer dichromate are mixed, shows excellent sensitivity and adhesion in close proximity to 365 ., the maximum luminescence peak of light source ultra high pressure mercury because it has maximum absorption peak at 345.365 ., but it has the drawback that it causes heavy metal contamination by chromium. 2 Accordingly, photoresist compositions comprising polyvinyl alcohol and SbQ(4-[2-(4-formyl phenyl)ethenyl]-l-methyrpyridium salt) have been recently proposed. They have merits in that they can provide photoresist compositions by a simple method without requiring separate processes such as stirring process resulting from mixing by applying as a photoresist composition a mixture of PVA-SbQ obtained from the reaction of polyvinylalcohol with SbQ, unlike prior polymer blending process where polymers and photosensitizers were introduced by separate processes and mixed. However, while the luminescent peak of ultra-high temperature mercury, etc. shows its maximum peak around 365 . and 405 ., the PVA-SbQ compound shows its maximum absorption peak at 345 . and accordingly, only low sensitivity of 335 . which is the luminescent peak of mercury, etc. can be employed. Therefore, it has the problem that exposure time to light is prolonged. SUMMARY OF THE INVENTION In order to solve the problems of the prior arts, it is an object of the invention to provide a negative photoresist composition capable of preventing environmental hazard of Cr and increasing sensitivity by the suitable selection of light by light absorption bands pursuant to processing conditions when exposed to light and at the same time, striving for quality Upgrade by enabling the production of DOT/STRIPE photoresist membranes having excellent adhesion and resolution when applied to B/M manufacturing process for CRT,* shadow mask manufacturing process, etc. Also, it is another object of the invention to provide a method of forming a B/M for CRT and a method of preparing a shadow mask with remarkably improved qualify as 3 DOT/STRIPE photoresist membranes having excellent adhesion and resolution can be obtained. To achieve the aforementioned objects, the present invention provides a negative photoresist composition comprising: a) a poly(2-ethyl-2-oxazoline); b) an azide-based photosensitizer; and c) a pure water Also, the invention provides a method of forming a B/M for CRT using the photoresist composition. Also, the invention provides a B/M for CRT formed by the method of forming the B/M for CRT. Also, the invention provides a method of forming a shadow mask using the photoresist composition. Also, the invention provides a shadow mask formed by the method of forming the shadow mask. DETAILED DESCRIPTION OF THE INVENTION This invention is further described in detail. The negative photoresist composition; of this invention is characterized in that it comprises a) a poly(2-ethyl-2-oxazoline), b) an azide-based photosensitizer, and c) a pure water. For the poly(2-ethyl-2-oxazoline) (POZ, CAS No. 25805-17-8) of a) in the invention, a product named Aquazol poly(2-ethyl-2-oxazoline) manufactured by ISP Co. 4 can be used. The amount of the poly(2-ethyl-2-oxazoline) of a) in the invention is preferably 1 to 15 % by weight. If the amount deviates from the above ranges, adhesion is decreased, deformation occurs in the configuration of patterns to be intended to form and further, irregular patterns may be caused. For the azide-based photosensitizer of b) in the invention, ordinary azide-based compounds can be used and more particularly, diazido stilbene disulfonic acid disodium salt, 2,5-bis(4'-azido-2'-sulfobenzylidene)cyclopentanone disulfonium salt, bis azide(4,4'-Diazidostilben-2,2'-disodium sulfonate, or DAP (2,5 Bis(4'Azide-2,Sulfonobenzylene)Pentanone disodium) can be used. Preferably, as the azide-based photosensitizer, diazido stilbene disulfonic acid disodium salt or 2,5-bis(4'-azido-2'-sulfobenzylidene)cyclopentanone disulfonium salt is used alone or by mixture. The amount of the azide-based photosensitizer in the invention is preferably 0.05 to 5 % by weight. If the amount deviates from the ranges, sufficient resolution is not obtainable or deformation in the configuration of patterns may occur or further, irregular patterns might be caused. More particularly, the poly(2-ethyI-2-oxazoline) and the azide-based photosensitizer are mixed preferably in a ratio of 100:5 to 100:25 by weight and more preferably 100:10 to 100:20 by weight. When the mixing ratio is within the above ranges, sufficiently enhanced adhesion and resolution can be obtained when applied to B/M manufacturing profess for CRT, shadow mast: manufacturing process, etc. and sensitivity is raised and-the uniform arrangement of photosensitive resin membranes is possible. The photoresist composition of the invention where the poly(2-ethyl-2-oxazoline) and the azide-based photosensitizer are mixed shows high absorption 5 coefficients around 336 ., 342 ., and 380 . and thus it enables light absorption bands to select and use light pursuant to processing conditions when exposed to light and accordingly, sensitivity to light is excellent. The pure water of c) in the invention preferably has purity available for semiconductor processing. For this, commercially available water can be used or industrially graded water can be used after being purified according to ordinary methods known in the pertinent art. The pure water for semiconductor processing is generally ultra pure water and preferably, water below 16 mft is used. The final solid content of the negative photoresist composition comprising the aforementioned components of the invention is preferably 1 to 15 % by weight and if the content of solids and photosensitizer deviates, deformation in the configuration of patterns to be intended to form may occur and further, irregular patterns might be caused. The invention may further polyvinyl pyrrolidone or PAD (poly acrylamide diacetoneacrylamide) and the amount of the polyvinyl pyrrolidone or PAD is preferably within 1 to 15 % by weight of the photoresist composition of the invention when combined with the poly(2-ethyl-2-oxazoline) of the invention and more preferably, it is used within maximum 400 parts by weight of 100 parts by weight of the poly(2-ethyl-2-oxazoline). In addition, the photoresist composition of the invention may further comprise a surfactant, a silane compound and/or a stabilizer that are used in conventional photoresist compositions besides the aforementioned components. 6 The silane compound functions as a surfactant, and it improves adhesion intensity so that the poly(2-ethyl-2-oxazoline) can adhere well to the inner surface of substrates. Also, the invention provides a method of forming a B/M for CRT or a method of forming a shadow mask using the negative photoresist composition of the invention, and the method of forming the B/M for CRT and the method of forming the shadow mask can be carried out in accordance with ordinary methods used in the pertinent art and the conditions can vary by other processing conditions and factors, if needed. The negative photoresist composition of the invention can increase sensitivity by the suitable selection of light by light absorption bands pursuant to processing conditions when exposed to light and at the same time, it can strive for quality upgrade as it enables the production of DOT/STRIPE photoresist membranes having excellent adhesion and resolution when applied to B/M manufacturing process for CRT, shadow mask manufacturing process, etc. For better understanding of the present invention, preferred embodiments follow. The following examples are intended to merely illustrate the invention without limiting the scope of the invention. EXAMPLES EXAMPLE1 4 G of a poly(2-ethyl-2-oxazoline) (Aquazol poly(2-ethyI-2-oxazolie, ISP Co.) was dissolved in 100 g of a pure water, to which 0.5 g of diazido stilbene disulfonic acid disodium salt was then added and mixed. Thereafter, 0.05 g of a surfactant, 0.05 g of a 7 silane compound and 0.0025 g of a stabilizer were added thereto and then evenly stirred to prepare a photoresist composition. EXAMPLE 2 With the exception that a mixture of 0.3 g of diazido stilbene disulfonic acid disodium salt and 0.3 g of 2,5-bis(4'-azido-2l-sulfobenzylidene)cyclopentanone disulfonium salt was used instead of 0.5 g of diazido stilbene disulfonic acid disodium salt in Example 1, the same method as Example 1 was performed. EXAMPLE 3 With the exception that 2,5-bis(4,-azido-2'-sulfobenzylidene)cyclopentanone disulfonium salt was used instead of diazido stilbene disulfonic acid disodium salt in Example 1, the same method as Example 1 was performed. EXAMPLE 4 With the exception that a mixture of 1.2 g of poly(2-ethyl-2-oxazo!ine) (Aquazol poly(2-ethyl-2-oxazoline, ISP Co.) and 2.8 g of polyvinyl pyrrolidone was used instead of 4 g of poly(2-ethyl-2-oxazoline) (Aquazol poly(2-ethyl-2-oxazoline, ISP Co.) in 100 g of a pure water in Example 1, a photoresist composition was prepared in accordance with the same method as Example 1. COMPARATIVE EXAMPLE 1 8 A photoresist composition was prepared using the prior polyvinylpyrrolidone and azide-based photosensitizer. COMPARATIVE EXAMPLE 2 A photoresist composition was prepared using the prior polyvinylalcohol and sodium dichromate. COMPARATIVE EXAMPLE 3 A photoresist composition was prepared using the prior polyacrylamide diacetoneamide and azide-based photosensitizer. After the photoresist compositions of Example 1 to 4 and Comparative Examples 1 to 3 were applied to the preparation of B/M for CRT and the preparation of shadow masks, adhesion and resolution were measured and the results are shown in Table 1 below. The adhesion is replaced by the degree of rigidity by the measurement of the intensity of screened P/R layers. Adhesion data was collected by measuring the amount of being pressed when the force of 3 gf was applied by a hardness measurer and as the values are less, adhesion ig better. Resolution was evaluated by naked eyes through a microscope and the higher the score, the better. Table 1 Example No. Comparative Example No. 1 2 3 4 1 2 . 3 9 Adhesion (um) 0.35 0.33 0.30 0.36 0.53 0.46 0.48 Resolution 4 5 5 5 5 2 4 From Table 1 above, it can be seen that the photoresist compositions of Examples 1 to 4 wherein the poly(2-ethyl-2-oxazoline) and the azide-based photosensitizer were used in accordance with the invention showed excellent sensitivity as well as superior adhesion and resolution in comparison with Comparative Examples 1 to 3 wherein the prior polyvinylpyrrolidone, polyvinylalcohol or polyacrylamide diacetoneacrylamide polymers was used. The negative photoresist composition in accordance with the invention can prevent the environmental hazard of Cr and increase sensitivity by the suitable selection of light by light absorption bands pursuant to processing conditions when exposed to light and at the same time, it strives for quality upgrade by enabling the production of DOT/STRIPE photoresist membranes having excellent adhesion and resolution when applied to B/M manufacturing process for CRT, shadow mask manufacturing process, etc. 10 We claim, 1. A negative photoresist composition comprising: a) a poly(2-ethyl-2-oxazoline); b) an azide-based photosensitizer; and c) a pure water 2. The negative photoresist composition according to claim 1 wherein the poly(2-ethyl-2-oxazoline) and the azide-based photosensitizer are mixed in a ratio of 100:0.5 to 100:25 by weight. 3. The negative photoresist composition according to claim 1 wherein the azide-based photosensitizer of b) is selected from the group consisting of diazido stilbene disulfonic acid disodium salt, 2,5-bis(4'-azido-2'-sulfobenzylidene)cyclopentanone disulfonium salt, bis azide(4,4'-Diazidostilben-2,2,-disodium sulfonate, DAP (2,5 Bis(4'Azide-2'Sulfonobenzylene)Pentanone disodium) and a mixture thereof. 4. The negative photoresist composition according to claim 1 wherein the final solid content of the negative photoresist composition is 1 to 15 % by weight. 5. The negative photoresist composition according to claim 1 further comprising at least one additive selected from the group consisting of a surfactant, silane compound, and stabilizer. 11 6. A method of forming a B/M for CRT using the photoresist composition of claim 1. 7, A B/M for CRT formed by the method of claim 6. 8. A method of forming a shadow mask using the photoresist composition of claim 1. 9. A shadow mask formed by the method of claim 8. 10. Negative Photoresist Composition as herein described forgoing description. Dated this 21st day of March 2006. 12 Dr. Rajeshkumar H. Acharya Advocate & Patent Agent For and on Behalf of Applicant ABSTRACT This invention provides a negative photoresist composition and in particular, it provides a negative photoresist composition comprising a poly (2-ethyl-2-oxazoline), an azide-based photosensitizer and a pure water. The negative photoresist compositions of the invention can prevent environmental hazard, replacing photoresists to which Cr is applied when they are applied to B/M manufacturing process for CRT, shadow mask manufacturing process, etc., and they can increase sensitivity by the suitable selection of light by light absorption bands pursuant to processing conditions when exposed to light so that DOT/STRIPE photoresist membranes having excellent adhesion and resolution can be obtained.

Documents:

397-mum-2006-abstract(granted)-(29-6-2010).pdf

397-mum-2006-abstract.doc

397-mum-2006-abstract.pdf

397-mum-2006-cancelled pages(2-3-2010).pdf

397-MUM-2006-CLAIMS(AMENDED)-(2-3-2010).pdf

397-mum-2006-claims(granted)-(29-6-2010).pdf

397-MUM-2006-CLAIMS(MARKED COPY)-(2-3-2010).pdf

397-mum-2006-claims.doc

397-mum-2006-claims.pdf

397-mum-2006-correspondence(11-3-2008).pdf

397-MUM-2006-CORRESPONDENCE(23-3-2009).pdf

397-MUM-2006-CORRESPONDENCE(IPO)-(2-3-2010).pdf

397-mum-2006-correspondence(ipo)-(29-6-2010).pdf

397-mum-2006-corresspondece-received ver-040706.pdf

397-mum-2006-corresspondece-received ver-210306.pdf

397-mum-2006-description (complete).pdf

397-mum-2006-description(granted)-(29-6-2010).pdf

397-MUM-2006-ENGLISH TRANSLATION OF PRIORITY DOCUMENT(23-3-2009).pdf

397-mum-2006-form 1(20-4-2006).pdf

397-mum-2006-form 18(12-2-2008).pdf

397-mum-2006-form 2(granted)-(29-6-2010).pdf

397-mum-2006-form 2(title page)-(granted)-(29-6-2010).pdf

397-mum-2006-form 26(20-4-2006).pdf

397-mum-2006-form 3(20-4-2006).pdf

397-MUM-2006-FORM 3(23-3-2009).pdf

397-mum-2006-form 5(20-4-2006).pdf

397-mum-2006-form-1.pdf

397-mum-2006-form-2.doc

397-mum-2006-form-2.pdf

397-mum-2006-form-3.pdf

397-mum-2006-form-5.pdf

397-MUM-2006-REPLY TO EXAMINATION REPORT(2-3-2010).pdf