31.1 INTRODUCTION

Semiconductor manufacturing is an established yet rapidly advancing industry. Companies are continually challenged to meet market demands by delivering increasingly sophisticated products in high volume, on time, and more cost-effectively than ever before. As Moore s law has driven smaller feature sizes, cost-effectiveness has driven a shift to larger wafers. Together, these forces have added significantly to process development and manufacturing complexity. In addition, current market conditions require manufacturers to introduce and ramp production of new products more quickly than was attainable even a few years ago. To do this, it requires adopting entirely new approaches to yield management (YM) that not only deliver higher yields but also achieve maturity levels more quickly than ever before.

Traditionally, capital expenditures for production equipment have had the highest priority, while expenditures for yield growth and assurance have been of secondary importance. In the past, yield improvement systems were not seen as value added processes and were justified based only on expected steady-state yield gains. A better metric to understand the significance of yield management evaluates the cost benefits for the engineer s ability to detect, fix, and quickly recover (DFQR) from unexpected yield busts. The productivity losses resulting from these unexpected events are more costly to the fab than not meeting the planned yield growth because of the immediate impact to on-time deliveries and product performances.

As it is reasonable to assume that these yield issues will occur early in a process ramp, it...