| PATENT ASSIGNEE'S COUNTRY | UK |
| UPDATE | 07.99 |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT CLAIMS |
Claim No. 1: Method for prodg film forming novolak resin - Condensing formol with phenols in presence of acid cata lyst - Then incorporating a presynthesized polymer of multihydro xylated benzene with ketone & thereby prodg novolak re sin block copolymer with the multi-hydroxybenzene/ketone moiety incorporated as part of block copolymer - Isolating novolak block copolymer by removing unreacted formol or phenols - Adding to copolymer water soluble organic polar solvent (15 - 40 % solids) - Adding deionized water; thereby precipitating novolak block copolymer & soln of remaining unreacted phenols, oligomers & useless monomers - Removing soln - Adding water soluble organic polar solvent to precipitated copolymer & thereby providing soln (15 - 40 % solids) - Adding deionized water, thereby again precipitating novo lak copolymer & removing remaining soln - Dissolving novolak block copolymer ppcc in photoresist solvent, then removing any remaining water & polar solvent by distn under vacuum & low T & thereby prodg soln of film forming fractionated novolak resin block copolymer in said photoresist solvent Claim 6: Method for prodg a positive photoresist compn having supe rior lithographic performance - All steps of Claim 1 - Last additional step. Providing an admixt.: -- Photosensitive comp. -- Film forming fractionated novolak resin block copolymer -- Additional photoresist solvent |
| PATENT PHOTOCOPY | Available on request |
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