The solution to enhance i-line stepper applications by improviing process overlay accuracy

Canon has developed the world´s first stepper with the shot shape compensator called “SSC”, which independently controls x and y magnification of shots on a wafer. This SSC function enables steppers to achieve overlay accuracy equivalent to scanners. The most suitable application of this function is back side illumination (BSI) image sensors, which has large distortion on wafers because of bonding and thinning processes. In this paper, we will provide the detailed descriptions along with the exposure results using our new solutions.