System and method for selectively laser processing a target structure of one or more materials of a multimaterial, multilayer device
AssigneeElectro Scientific Industries, Inc.
InventorsYunlong Sun, Craig D. Hutchens
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 2.0 .mu.m (30) optimizes the absorption contrast between many high conductivity materials (e.g., metals) and silicon substrates and permits the use of laser output in a wider range of energy or power levels, pulse widths, without risking damage to the silicon substrates or adjacent circuit structures. Existing link processing laser systems can be readily modified to operate in the 1.2 to 3.0 .mu.m range.
Claims26
A method for selectively processing a multilayer, multimaterial device that includes a substrate and a high conductivity 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 predetermined spatial dimensions;
- and
- directing the laser output to illuminate the target structure, the predetermined wavelength having a value that represents a sufficiently large absorption contrast between the target structure and the substrate to change a physical property of the target structure but leave substantially unchanged the physical property of the substrate within the spatial dimension of the laser output.
A laser system for selectively processing a target structure of a multilayer, multimaterial device including a substrate, the 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 critical dimensions, power, and wavelength selected to exploit differences in the wavelength sensitive properties of the target structure and the substrate such that the target structure within the critical dimensions is effectively processed and the substrate within the critical dimensions is relatively undamaged by the laser output.
A method for employing a laser system to process high conductivity link structures forced on a silicon substrate, comprising:
- generating laser output in a wavelength range of about 1.2 .mu.m to 3.0 .mu.m;
- and
- directing the laser output at a high conductivity link structure such that it is effectively processed but the substrate is relatively undamaged.
A method for employing a laser system to process a highly conductive material of a target structure forced on a substrate;
- comprising:
- positioning the target structure in an environment having an oxygen concentration;
- generating a laser output having energy sufficient to process the material of the target structure;
- and
- directing the laser output to process the target material within the environment, wherein the oxygen concentration is sufficient to substantially convert any slag resulting from processing of the target structure to a substantially non-conductive oxide.
Dependencies are inferred from the claim text.