Intergrated circuit substrates

Abstract

An integrated circuit substrate is made by exposing a mask to a composite representation of the pattern of integration of several different dice. The mask is exposed several times to produce several composite representations on the mask. Several different composite representations may be formed on the same mask. Identical aligned composite representations are checked by optically comparing corresponding dice in different composite representations via respective optical systems. The several composite representations on the mask are transferred simultaneously to the substrate to reproduce the pattern of integration of the dice at a plurality of locations in the substrate. The area of the mask covered by the composite representations may be greater than the usable area of the substrate such that for at least two of the composite representations only a portion of the composite representations is reproduced on the substrate, some of those dice not reproduced in one of the composite representations being reproduced in the other of the two composite representations. One half of the mask may have composite representations relating to one processing step, while the other half of the mask relates to a different processing step, the mask being reoriented after the first step so that the part of the substrate exposed initially to the one half of the mask is subsequently exposed to the other half of the mask, the other part of the substrate being rejected.