The fabrication of integrated circuits involves creation of patterned, multilayer, thin film structures composed of insulators, semiconductors, and conductors. Typically, these structures are constructed by using photolithographic techniques in conjunction with additional processing steps, including chemical vapor deposition (CVD), etching, doping, etc. Some of steps (e.g. wet etching) lack sufficient resolution for high ensity devices, while others (e.g. high temperature CVD) subject the wafer to extreme conditions that may damage underlying structures. This has resulted in increased interest in laser processing of microelectronic devices. The PI's research is focused on laser induced deposition. The process of scanning a laser beam across a substrate, causing reactants in either the gas, liquid or solid phase to react and deposit on the substrate is referred to as laser direct- write Potential applications of laser processing include repair and modification of devices and masks, production of small quantities of custom devices, and construction of new structures that take advantage of the laser controlled chemistry and the optical properties of the precursor and substrate materials. This equipment grant will provide funds for the purchase of a laser directwrite system for investigating fundamental mechanisms underlying nonlinear morphological effects in direct laser writing of metal and semiconductor lines from spun-on metalorganic layers as well as gaseous reactants. The system consists of a microscope for focusing radiation from an Ar+ laser onto a substrate. An x-y translation stage moves the substrate relative to the laser beam so that lines may be written. The nonlinear behavior that will be investigated include multiplicity phenomena, periodic patterns, and volcano-shape deposits. These effects are observed over a wide range of operating conditions in a large number of applications including the deposition of gold from organogold films, silicon from silane, and Y-Ba-Cu-O superconductors from spun-on metalorganic films. The overall goals are to understand the underlying fundamental processes and to develop predictive models that may be used to prevent or control the nonlinear behavior.
