High Uniformity Hot Plate Adapter
Original Publication Date: 1983-Feb-01
Included in the Prior Art Database: 2005-Feb-06
Large hot plates available from laboratory supply companies are incompatible with modern lithographic processing and its need for precise control of all steps. Many processes, for example, require very fine control of the post exposure bake step. Many resist systems lose sensitivity rapidly as a function of high prebake temperature. Yet, wafers have become progressively larger, requiring commensurately larger hot plates for reasonable throughput. Commercially available hot plates, having square surface areas approximately 24 cm. on a side, are commonly employed for hot plate baking operations. But such units have both spatial and temporal non-uniformity which is unsuited to lithography.