METHOD AND APPARATUS FOR PROCESS CONTROL

摘要

In order to investigate the development of a photoresist layer (2) on an optical master disk (I) by developing fluid (14), a transparent body (4, 35, 50) is brought into contact with the developing fluid (14). A light beam (6) is then incident on the optical master disk (I) from a source (5) and a diffracted beam (8) passes through the developing fluid (14) and the transparent body (4, 35, 50) to a detector (9). In this way the optical path of the diffracted beam (8) is stable. Preferably, the diffracted beam (8) is generated from the incident light beam (6) by reflection, and preferably it is a first-order diffracted beam. It is also preferable that the incident light beam (6) is modulated. The development of the photoresist layer is then monitored by monitoring changes in the diffracted light beam (8) detected by the detector (9).