REAL-TIME CLOSED LOOP CONTROL IN A GATE ETCH PROCESS

摘要

To ensure proper functioning of integrated circuits, device and interconnect dimensions have to be controlled precisely. In some advanced logic fabs, devices with critical dimension (CD) less than 40 nm are being manufactured on a regular basis. These manufacturers rely heavily on advanced process control (APC) techniques to achieve the desirable process repeatability. A critical part of APC is performed by metrology tools on critical dimension measurements. Up until recently most fabs have used standalone metrology tools based on CDSEM. In this paper, a fully integrated Transforma? Closed Loop (CL) Patterning System is used to facilitate nanometer gate etch control by enabling, for the first time, real-time multi-parameter feedforward and feedback measurements. This technology represents a significant improvement on the process capability index and reduction in process cycle time.