Next generation mask coordinate measuring technology

Abstract

As LSI's have become far more highly integrated and the pattern has become much finer, it is demanded in mask production to position the pattern even more accurately. Nikon Corp. currently provides the XY-3i as a mask pattern coordinate measuring machine, but it will not be long before one with even higher accuracy will be required. In this paper, we present two major key technologies to be used for the next-generation coordinate measuring machine. First, we will discuss the problem of coordinate measurement error caused by the flexure of a mask. We will propose a new flexure compensation method based on a concept that is different from what is used for the XY-3i, and report the result of our experiment and simulation to prove that this method is appropriate. Second, we will examine experimentally by what mechanism the temperature fluctuation in the machine may affect the accuracy of measured coordinates, and make clear what will be required to develop the next-generation machine.