Method for monitoring dosage/focus/leveling
Abstract
Abstract A method for monitoring dosage/focus/leveling is provided. A control wafer is provided and divided into several regions. Five of the regions near the center of the wafer are used to monitor normally. Other regions are used as dummy shots. When a situation of a stepper changes greatly, the dosage/focus/leveling of the control wafer is monitored using the dummy shots. In monitoring exposure dosage, the middlemost region is monitored. One of the five regions, which is the most central, is exposed with a low exposure energy to enhance sensitivity of critical dimension versus energy. Many points with small areas are developed in the centermost region to take sufficient samples. Since the developed points are close, effects from the nonuniformity of development and from the nonuniformity of the photoresist layer are prevented. In focus/leveling monitoring, a curve diagram of exposure dosage versus critical dimension is provided. An exposure parameter is taken at a range of the curve with a large slope. The focus/leveling is monitored at the other four regions near the middlemost region.
Inventors
- 👤 Cheng-Kuan Wu
- 👤 Te-Yang Fang
Bibliographic Details
Claims Analysis
Total Claims: 9References Cited (Backward Citations)
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