INNOVATIONS FOR THE ADVANCEMENT OF DIRECT-WRITE CIRCUIT BOARD FABRICATION

INNOVATIONS IN THE MANUFACTURE OF A VERY WIDELY USED ELECTRONIC COMPONENT, THE CIRCUIT BOARD, ARE BEING CONSIDERED. FAST PHOTOGRAPHIC SYSTEMS WHICH WOULD PROMOTE THE USE OF COMPUTER-CONTROLLED DIRECT WRITE LASER TECHNIQUES ARE BEING INTRODUCED. CONVENTIONAL FABRICATION INVOLVES CONTACT PRINTING OF A MASK PATTERN ONTO THE CIRCUIT BOARD PHOTORESIST. THE PROCESS OFFERS MASS PRODUCTION, HIGH THROUGHPUT BUT SIGNIFICANT LIMITATION SIN FELXIBILITY; ESPECIALLY FOR SMALL BATCH OR PROTOTYPE RUNS. HOWEVER, UTILIZATION OF MASK-FREE DIRECT-WRITING ON PHOTORESIST REMAINS HELD BACK BECAUSE HIGH THROUGHPUT SEPCIFICATIONS OVERBURDEN EXISTING DIRECT-WRITE SYSTEMS. RESEARCHERS ARE DEVELOPING TWO INNOVATIONS FOR INCREASING DIRECT-WRITE THROUGHPUT BY EFFECTIVELY INCREASING BOTH PHOTORESIST SPEED AND SPECTRAL RANGE, THUS UTILIZING LASERS IN THE 500-700 NM RANGE, HERETOFORE NOT CONSIDERED AS DIRECT-WRITE EXPOSURE SOURCES. A TWO-LAYER RESIST CONCEPT COMPRISING A SILVER PHOTOGRAPHIC COATING OVER A PHOTOPOLYMER SUBLAYER IS BEING EXPLOITED. A FAST, SILVER-BASED PHOTOSENSITIVE CIRCUIT BOARD LAMINATE THAT PROCESSES TO A CONDUCTING WIRING BOARD PATTERN, AVOIDING THE PHOTORESIST STEP IS EMPLOYED.