Abstract: The present invention teaches the deposition of a pattern of interconnecting lines and bond pads. Passivation layers are deposited over this metal pattern. A layer of photosensitive polyimide is deposited over the passivation layers. This layer of photosensitive polyimide is patterned, exposed and developed to expose the underlying bonding pads. The remaining polyimide is cured and cross-linked and remains in place to serve as a buffer during further device packaging. Key to the present invention is that the remaining photosensitive polyimide is not removed after the bond pad has been exposed.

Abstract: A low cost, fast method for evaluating the effects of lens heating in a step and repeat projection system is disclosed. The first step is to form a series of photoresist images on a single substrate in the same way as would be done during normal stepping and repeating. The first few images, located centrally, will be produced by a cool lens. As more images are generated, the lens gradually heats up so that the final few images, which are placed alongside the `cool` images, will be produced by a hot lens. Critical dimension bars are present in all image fields (at diagonally opposite corners and in the center), their size in the developed photoresist being an indication of the extent to which the focal plane has drifted. This is then used to compute correction factors for the manufacturer's scaling constants and/or to evaluate the extent, if any, of curvature of field in the projected images.