摘要 |
A method for detecting microscopic differences in the thickness of a photoresist film coated on a wafer through naked eyes, which is capable of accurately controlling the critical dimension of the photoresist film patterns even in devices of 256 M DRAM or more and allows the yield to be analyzed with accuracy, comprising the steps of: subjecting the photoresist film to thermal treatment at a low temperature, to make some low molecular weight compounds or solvent molecules to remain within the photoresist film; forming a special material layer over the photoresist film within a certain thickness; and executing high-temperature thermal treatment, to gush up the remaining low-molecular weight compounds or solvent molecules from the photoresist film through relative thin parts of the special material layer.
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