Laser microphotochemistry for use in solid-state electronics

A focused, ultraviolet (UV) laser beam has been used to produce micrometer-sized chemical processes on solid surfaces. These processes are initiated by the photodissociatlon of a molecular gas in the vicinity of the gas-solid interface. Depending on whether the active photofragment reacts with or is adsorbed on the solid, microetching or microdeposition occurs. Both the surface properties of the solid and the gas-phase kinetics contribute to the process localization. Metal alkyls and methyl halides have been used as parent molecules for deposition and etching, respectively. A focused, 3 mW UV laser is sufficiently intense to produce satisfactory rates for both processes. Several applications of this small-scale photochemistry to microelectronics have been investigated.