Gate CD control using APC for high mix product line

We succeeded in developing the advanced process control (APC) algorithm in gate etching for high mix product line. The gate length is controlled by adjusting the critical dimension (CD) bias based on the optimal etching condition calculated by APC. The CD bias depends on the device pattern as well as the etching condition. Therefore, it is necessary to compensate for the CD bias according to the device pattern in the mix product line. Our APC algorithm enables to adjust the CD bias offset for high mix products automatically. The APC was applied to the sub-micron gate etching of 300-mm wafers. As a result, the gate lengths among the mix products approached to the targets using APC. This demonstrates that our APC algorithm is effective for the high mix product line.