Yield enhancement: reduction in defect density with improvement in the photolithography process

With the erosion of the average selling price and shrinking profit margins of the semiconductor industry, yield improvement has been elevated to new levels. Through Integrated Yield Management Team (IYM) efforts, it was discovered that the photolithography area was the major contributor to unusually high defect density levels. Using a team approach, individuals were selected and charged with the task of lowering these levels in record time. Identifying and quickly correcting sources of defects were done in parallel and around the clock. Because the photolithography room is the hub of any wafer fabrication facility, it is essential that it be a series of clean operations; daily product monitoring ensures that interactions between individual processes and equipment remains constant, and defect excursions are recognized immediately. Of equal importance, is the monitoring of individual tools. With this paper, it will be shown that using a team approach to problem solving, the defect density was effectively reduced, and an improvement was made in the operation of the fab.