Method and system of distortion compensation in a projection imaging expose system

This invention relates to photolithography systems for high resolution circuit imaging, and specifically relates to step and repeat photo systems imaging multiple chip carriers through a projection lens onto large circuit panels or substrates. More particularly, this invention relates to photolithography systems employing a large area projection lens (e.g. 6-8 inch diameter field of view) and provides for a system and method of configuring the image magnification responsive to distortion factors observed in a panel receiving the image. A photolithography imaging system and method that performs the tasks of mask alignment, panel recognition, establishing position offsets and adjusting mask rotation for accurate overlay imaging of the mask onto the panel, and correctly adjusting image magnification or reduction to properly size each stepped image to the panel distortion. This invention applies more directly to substrate panels whose dimensional stability is found difficult to control, repeatedly. More specifically, it applies to panels whose X axis distortion factor varies greatly from its Y axis distortion factor and the average adjustment of the image magnification or reduction does not satisfy tight registration requirements. What is new is that the calculation of the magnification or reduction adjustment is based on the mask image dimensions.