JPS56145332A - Detecting device for state of proper development - Google Patents

Abstract

PURPOSE:To detect the state of proper development easily and accurately by monitoring the state of a diffraction ray by using a pattern appearing in a developed body as a diffraction grating. CONSTITUTION:On the occasion of developing treatment, the original disc OD of a disc is rotated and water 10 and a developing solution 11 are supplied on to the original disc OD from nozzles 17 and 18. Laser beams emitted from a light source LS are transmitted by the original disc OD, while they are turned into the diffraction gratings when the arrangement of pits is formed in a photoresist layer 2, and the diffraction beams of zero-order, primary order and other orders, etc. are emitted from the back surface of the original disc OD. The diffraction beam of zero order received by an element PE0 provided on a back-surface cover RC and the diffraction beam of primary order received by an element PE1 are transduced into electric signals by photoelectric transducers D0 and D1 and amplified by amplifiers AMP0 and AMP1, respectively, and then are given to a comparator COMP through the intermediary of low-pass dilters LPF0 and LPF1. when the original disc OD turns to be in the state of proper development, a development completion pulse is sent from the comparator COMP to a terminal OUT and thereby the supply of the developing solution is stopped.