Fully Automatic Repair Process for Photoemulsion Masks
Original Publication Date: 1985-Sep-01
Included in the Prior Art Database: 2005-Feb-19
A fully automatic repair process is described for photoemulsion masks (glass masters) used as exposure masks during the manufacture of circuit boards. Such masks consist of a glass plate supporting a high- resolution photoemulsion. By means of a light beam recorder, the photoemulsion is exposed according to the desired conductor pattern. After development, the exposed zones appear as a black pattern on a transparent ground. Exposure masks thus produced are inspected by means of an automatic image analysis system (AIAS). Defective areas in the circuit pattern are detected, and the associated coordinates are stored. For repairing photoemulsion masks fully automatically, reference data are generated for the AIAS, by means of which the entire circuit pattern is defined in the form of a vector plot (Fig. 1).