Study on Optimization of Silicon Warp in CCD Heat Processing

The effects of silicon warp on lithography critical dimension uniformity were studied by analyzing the variety of silicon warp in the heat processing by surface metrology.The result indicates the silicon warp has great effects on the uniformity of lithography critical dimension,that is,bigger warp brings lower uniformity.The silicon warp is reduced by optimizing gate oxide processing,the speed of tube heating and cooling process and the speed of tube get-in and get-out.The critical dimension uniformity is reduced from ±4% to ±2%.