Laser system and method for selectively severing links
AssigneeElectro Scientific Industries, Inc.
InventorYunlong Sun
Life of this patent
Estimating the term…
Abstract
A laser system and processing method exploits the absorption contrast between the materials from which a link (12) and an underlying substrate (22) are made to effectively remove the link from the substrate. Laser output in a wavelength range of 1.2 to 3 .mu.m (30) optimizes the absorption contrast between many materials (e.g., metals, polysilicon, polycides, or disilicides) and integrated circuit substrates (e.g., silicon, gallium arsenide, or other semiconductors) and permits the use of laser output in a wider range of energy or power levels, pulse widths, and spot sizes without risking damage to the substrates or adjacent circuit structures. Existing link processing laser systems can be readily modified to operate in the 1.2 to 3 .mu.m range.
Claims21
A method for selectively processing a multilayer, multimaterial device that includes a substrate and a nonmetal target structure having respective first and second wavelength-sensitive light absorption characteristics, the first and second absorption characteristics having different light absorption properties that provide different light absorption contrasts for different wavelengths of light, comprising:
- generating at a predetermined wavelength a laser output having a predetermined spatial spot size;
- and
- directing the laser output to illuminate the nonmetal target structure, the predetermined wavelength providing a sufficiently large absorption contrast between the nonmetal target structure and the substrate to change a physical property of the nonmetal target structure but leave substantially unchanged the physical property of the substrate within the spatial spot size of the laser output.
A laser system for selectively processing a nonmetal target structure of a multilayer, multimaterial device including a substrate, the nonmetal target structure and substrate having wavelength-sensitive properties, comprising:
- a pumping source;
- and
- a lasant positioned in a resonator cavity adapted to be pumped by the pumping source to provide a laser output having a spatial spot size, power, and wavelength selected to exploit differences in the wavelength-sensitive properties of the nonmetal target structure and the substrate such that the nonmetal target structure within the spatial spot size is effectively processed and the substrate within the spatial spot size is relatively undamaged by the laser output.
A method for employing a laser system to process nonmetal link structures formed on a silicon, gallium arsenide, or other semiconductor substrate, comprising:
- generating laser output in a wavelength range of about 1.2 to 3 .mu.m;
- and
- directing the laser output at the nonmetal link structure such that it is effectively processed but the substrate is relatively undamaged.
Dependencies are inferred from the claim text.