Advanced process control using automated recipe editing triggered by SPC

Maintaining product measurements and tool parameters within tolerance limits is insufficient, if a semiconductor manufacturer desires to remain competitive. National Semiconductor Corporation, South Portland, Maine (NSME) manufactures a variety of semiconductor products with a diverse mixture of process flows. For chemical vapor deposited (CVD) films, it is a challenge to maintain each unique deposition process on-target for film thickness, while not wasting valuable resources and process time running qual wafers to validate adjustments to those processes. NSME uses proprietary software to respond to minute deviations (in some cases, less than 1%) from target film thickness by automatically making small adjustments to process recipe deposition times for individual process chambers. While constantly minimizing thickness deviation from target, these adjustments are performed in a way that minimizes tool impact.