Single-wafer/mini-batch approach for fast cycle time in advanced 300-mm fab

Advanced 300-mm application specific integrated circuit/system-on-chip (ASIC/SOC) fabs with multiproduct and multiprocess models will require both a high level of flexibility and efficiency to achieve cost effective manufacturing cycle times. One of the main detractors for cycle time and fab flexibility is a batching requirement on certain types of processing that makes lots waiting for the batch to be completed and generates wip bubbles downstream. This paper reviews the front-end steps within a semiconductor manufacturing flow where batching requirements may be replaced by single-wafer or mini-batch alternatives for improved cycle time. Encouraging process results for front-end applications for potential single-wafer replacements are presented. It is demonstrated that single-wafer oxidation, LPCVD and cleaning offer a large potential cycle time gain but currently have different levels of maturity as potential batch technology replacements. In addition to the process feasibility, a DOE based on dynamic simulation is conducted enabling the quantification of potential gains in cycle time obtained by switching to single-wafer or mini-batch strategy instead of batch strategy, preferring integrated metrology and reducing mini-lots size. It shows that, in comparison to the baseline model (100%), the manufacturing cycle time may decrease down to 65% for mini-lots and to 78% for standard production lots.