Use of silane-based primer on silicon wafers to enhance adhesion of edge-protective coatings during wet etching: application of the TALON Wrap process

摘要

Hydrolyzed silane primer solutions were made of an organosilane in glycolether diluted with a large amount of water with or without an acid as a catalyst. The newly developed primer compositions exhibited an extended shelf life of 3 months or more. The compositions were specially designed to accommodate ProTEKTM. layer adhesion in the TALON Wrap. process. In this application, a spin-coatable polymeric material, ProTEKTM., is applied as the protective coating to coat the top, edge, and underside rim of the wafer in preparation for backside etching. By applying an underlayer of primer and an overlayer of ProTEKTM. coating to the top, edge and the bottom side rim of the wafer, an effective encapsulation of the wafer was achieved by using a custom-designed baffle. Each layer was applied by spin coating followed by baking at a wide temperature range. Thermal processing was followed by wet etching in KOH at an elevated temperature for . 10 hr. Post-etched wafers were rinsed with deionized (DI) water. Excellent edge profiles without "knife-edges" were obtained after etching the unprotected areas of the wafer. The process is fully automated because it is carried out in the TALONTM automated wafer-processing tool. Intact films with no lifting or peeling were obtained during or after the KOH etch process/DI rinse for silicon substrates.