Closed loop registration control (RegC) using PROVE as the data source for the RegC process

At sub 4X nm nodes in memory and sub 3X nodes in logic devices mask registration (Reg) is becoming a significant yield limiting factor. This is especially true for Double Patterning Technologies (DPT) where mask to mask overlay on the wafer is heavily influenced by mask registration error. Getting advanced mask registration into specification is a challenge for all mask shops as the tight registration specs are driven by tight wafer overlay specs. The first step in meeting the registration spec challenge in the mask shop is to be able to measure registration with the required specifications. With PROVE® Carl Zeiss SMS has recently introduced into the market a new registration and overlay metrology system which utilizes 193nm illumination for high resolution and a six axes controlled stage. The second step in meeting the registration spec challenge is to actively correct for intrinsic registration errors on the mask. For this Carl Zeiss SMS has developed the RegC® tool. The RegC® tool is based on writing strain zones with the help of an ultrashort pulse laser in the bulk of the mask. The strain zones induce deformations in the mask which practically push the misplaced features to a new location that after removing scale and orthogonality (S/O) correctable errors reflects a smaller residual registration error. By combining the RegC® tool with data generated by PROVE® it is possible to close the loop on the registration control process in the mask shop without wafer print or mask re-write. In this paper we report the demonstration results of a closed loop process between PROVE® and the RegC® tools.