High Speed, High Accuracy Stage for Advanced Lithography

The development of a high-speed, very accurate XY stage for semiconductor lithography is proposed. Key features are: a grid-based metrology system which is immune to turbulence and has subnanometer resolution; a high-speed, light-weight XY stage capable of supporting 12" wafers, and including active control of all six degrees of freedom; and dual-loop servo systems for X and Y to provide fast long-range moves and highly accurate short-range positioning. If successful, this approach will provide all of the capabilities needed for the next generation of steppers for high throughput, high accuracy microlithography. This approach also promises to reduce the cost of the metrology system by at least a factor of two relative to the cost of a comparable, but less capable, laser interferometer system.