摘要 |
The post exposure bake cycle in a chemically amplified resist process is more precisely controlled by measuring the distance from multiple locations on the bottom of each processed wafer to a reference plane surface while the wafer is supported on a cool plate. Subsequent to measuring the distance, the wafers are transferred to the hot plate that has a series of controllable heating elements. The set temperature for the heating elements is established in response to the distances measured while the wafer is on the cooling plate. The measurements are taken by utilizing proximity sensors located within the cooling plate.
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