Method to produce a reference grid artifact for matching a MEBES 4500 system to an external reference

摘要

Abstract: It has been shown that mask composite pattern position errors can be reduced by more than 40% on the MEBES 4000 system if a reference grid is used to match a MEBES 4000 system to an independent metrology tool. It has also been shown that matching between MEBES systems can be significantly improved by use of the dynamic grid matching (DGM) feature of the MEBES 4500 system. Several methods of grid matching are possible on the MEBES 4500 tool, including generation of a physical reference artifact or 'golden plate.' This work defines a method to produce a golden plate artifact for use in system grid matching. The technique uses a second level (phase shift mask) alignment capability to a zero level target to place a reference grid pattern on the reticle. Subsequent exposures of this pattern overlaid on the same substrate with different orientations serve to reduce systematic and random errors of the exposure tool. The processed image can then be used as a reference artifact for different systems. If necessary, the procedure can be iterated to further improve accuracy. Results of this methodology to produce an artifact are presented as well as its application in system matching to reduce composite positional errors as measured by independent metrology tools. !3