Laser system and method for selectively trimming films

Abstract

A laser system and processing method exploits the absorption contrast between the materials from which a film and an underlying substrate (26) are made to effectively remove the film from the substrate. Laser output in a wavelength range of 1.2 to 3 .mu.m optimizes the absorption contrast between many resistive or conductive film materials (e.g., metals, metal alloys, polysilicon, polycides, or disilicides) and integrated circuit substrates (e.g., silicon, gallium arsenide, or other semi-conductors) and permits the use of laser output in a wider range of energy or power levels and pulse widths, without risking damage to the substrates or adjacent circuit structures. Existing film processing laser systems can be readily modified to operate in the 1.2 to 3 .mu.m range. The laser system and processing method also exploit a wavelength range in which devices, including any semiconductor material-based devices affected by conventional laser wavelengths and devices having light-sensitive or photo-electronic portions integrated into their circuits, can be effectively functionally trimmed without inducing malfunctions or function shifts in the processed devices, thus allowing faster functional laser processing, easing geometric restrictions on circuit design, and facilitating production of denser and smaller devices.

Dependencies are inferred from the claim text.