International Business Machines Corporation

James A Shurtleff

Kostas I Papathomas

Anilkumar Chinuprasad Bhatt

Jerome J Wagner

Gary S Ksenak

Kevin P Unger

A method is disclosed for using the simple, environmentally friendly organic compounds gamma-butyrolactone and benzyl alcohol to develop and to strip free radical-initiated, addition polymerizable resists, cationically cured resists and solder masks and Vacrel photoresists. In all cases the developers and strippers include gamma butyrolactone or benzyl alcohol. The developers and strippers optionally also include a minor amount of methanol, ethanol, isopropyl alcohol, propylene glycol monomethylacetate, ethylene glycol monomethyl ether, formamide, nitromethane, propylene oxide, or methyl ethyl ketone, acetone and water. During development of the photopatterned resist or solder mask, the unpolymerized regions are dissolved in the disclosed developers. During stripping of the resist or solder mask, the polymerized regions are debonded from a circuit board in the disclosed strippers. Following removal of the developers and strippers, any residual monomers or polymers of the resist or solder mask as well as residual developing solution and stripping solution are rinsed from the printed circuit package. A method is also disclosed for treating the combined developer and stripper rinse effluents in an activated biomass to reduce the biological oxygen demand of the developer/stripper/resist/solder mask waste streams.

Method for treating photolithographic developer and stripper waste

A method is disclosed for using the simple, environmentally-friendly organic compounds gamma-butyrolactone and benzyl alcohol to develop and to strip free radical-initiated, addition polymerizable resists, cationically cured resists and solder masks and Vacrel photoresists. In all cases the developers and strippers include gamma butyrolactone or benzyl alcohol. The developers and strippers optionally also include a minor amount of methanol, ethanol, isopropyl alcohol, propylene glycol monomethylacetate, ethylene glycol monomethyl ether, formamide, nitromethane, propylene oxide, or methyl ethyl ketone, acetone and water. During development of the photopatterned resist or solder mask, the unpolymerized regions are dissolved in the disclosed developers. During stripping of the resist or solder mask, the polymerized regions are debonded from a circuit board in the disclosed strippers. Following removal of the developers and strippers, any residual monomers or polymers of the resist or solder mask as well as residual developing solution and stripping solution are rinsed from the printed circuit package. A method is also disclosed for treating the combined developer and stripper rinse effluents in an activated biomass to reduce the biological oxygen demand of the developer/stripper/resist/solder mask waste streams.

Disclosed is a method of treating a process stream from a process producing a non-biodegradable alkylene carbonate stream. The alkylene carbonate is hydrolyzed in a strong, aqueous, alkaline solution to form an aqueous alkaline solution of the corresponding alkylene glycol. This solution is then acidified to a pH of about 8 to 8.5. The acidified solution is aerated in activated sludge to reduce the biological oxugen demand (BOD) of the solution.

Growing community of inventors

Endwell, NY, United States of America

James A Shurtleff