Full-wafer processing of laser diodes with cleaved facets
First Claim
1. A method for processing a plurality of semiconductor laser diodes with cleaved facets, starting with a laser structure comprising a plurality of layers formed on top of a laser substrate, comprising the steps of:
- a) defining the position of the facets to be cleaved by scribing a set of parallel scribed marks into the top surface of said plurality of layers, said scribed marks being substantially perpendicular to a predetermined optical axis of the lasers to be made, and having a predetermined laser length distance defining the length of a plurality of laser cavities of said laser diodes and a predetermined separation distance between the facets of neighboring laser diodes;
b) covering the uppermost portion of said layers with a protective etch mask that covers each laser diode to be made, extends over said scribed marks defining said laser length of each laser and includes a plurality of etch windows between said scribed marks defining the position of facets of neighboring lasers;
c) etching trenches at least into an upper portion of said laser structure through said plurality of etch windows, thereby leaving a lower portion including said substrate;
d) partly underetching said upper portion during a second etch step of said lower portion through said plurality of etch windows, whereby an undercut portion of a plurality of etch apertures extends under said upper portion past said scribed marks, so that said laser facets can be defined by cleaving said upper portion along said scribed marks without cleaving the whole laser structure;
e) cleaving said underetched upper portions along said scribed marks, thereby defining laser facets perpendicular to said layers and to said optical axis; and
f) separating said plurality of laser diodes by cleaving said lower portion between neighboring lasers.
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Accused Products
Abstract
A method for full-wafer processing of laser diodes with cleaved facets combining the advantages of full-wafer processing, to date known from processing lasers with etched facets, with the advantages of cleaved facets. The steps being: defining the position of the facets to be cleaved by scribing marks into the top surface of a laser structure comprising epitaxially grown layers, these scribed marks being perpendicular to the optical axis of the lasers to be made, the scribed marks being parallel, their distance (lc) defining the length of the laser cavities and the distance (lb) between the facets of neighboring laser diodes; and covering the uppermost portion with an etch mask pattern which provides for etch windows between the scribed marks defining the position of facets of neighboring lasers; and etching trenches into an upper portion of the structure defined by the etch windows; and partly underetching the upper portion during a second etch step such that the laser facets can be defined by cleaving the upper portion along the scribed marks without cleaving the whole laser structure; and ultrasonically or mechanically cleaving the upper portions being underetched along the scribed marks; and separating the laser diodes by cleaving them between neighboring lasers.
52 Citations
21 Claims
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1. A method for processing a plurality of semiconductor laser diodes with cleaved facets, starting with a laser structure comprising a plurality of layers formed on top of a laser substrate, comprising the steps of:
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a) defining the position of the facets to be cleaved by scribing a set of parallel scribed marks into the top surface of said plurality of layers, said scribed marks being substantially perpendicular to a predetermined optical axis of the lasers to be made, and having a predetermined laser length distance defining the length of a plurality of laser cavities of said laser diodes and a predetermined separation distance between the facets of neighboring laser diodes; b) covering the uppermost portion of said layers with a protective etch mask that covers each laser diode to be made, extends over said scribed marks defining said laser length of each laser and includes a plurality of etch windows between said scribed marks defining the position of facets of neighboring lasers; c) etching trenches at least into an upper portion of said laser structure through said plurality of etch windows, thereby leaving a lower portion including said substrate; d) partly underetching said upper portion during a second etch step of said lower portion through said plurality of etch windows, whereby an undercut portion of a plurality of etch apertures extends under said upper portion past said scribed marks, so that said laser facets can be defined by cleaving said upper portion along said scribed marks without cleaving the whole laser structure; e) cleaving said underetched upper portions along said scribed marks, thereby defining laser facets perpendicular to said layers and to said optical axis; and f) separating said plurality of laser diodes by cleaving said lower portion between neighboring lasers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification