US5284792A — Full-wafer processing of laser diodes with cleave…

Claim 1

Independent Claim 291 words

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.

Claim 2

Independent Claim 291 words

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.

Claim 3

Dependent Claim 40 words

The method of claim 1, in which said step of etching said trenches is continued through said laser structure exposing said laser substrate at the bottom of said trenches and said step of undercutting is performed in said laser substrate.

Claim 4

Dependent Claim 80 words

The method of claim 2, wherein a partially-cut pattern is cut at the backside of said laser substrate, said pattern consisting of perpendicular cuts defining rectangular sections, one side thereof being longer than said laser length distance and being parallel to the optic axis of the laser diodes, another side being perpendicular to said one side such that said substrate of said laser structure or the carrier substrate can be cleaved along these cuts to separate the individual laser diodes.

Claim 5

Dependent Claim 41 words

The method of claim 3, comprising a step of depositing at least one of a passivation, anti-reflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 6

Dependent Claim 41 words

The method of claim 2, comprising a step of depositing at least one of a passivation, anti-reflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 7

Dependent Claim 37 words

The method of claim 2, wherein the layers of said laser structure are separated from said laser substrate by a thin intermediate etch-stop layer, such that the etchant used for underetching does not attack said upper layers.

Claim 8

Dependent Claim 41 words

The method of claim 6, comprising a step of depositing at least one of a passivation, anti-reflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 9

Dependent Claim 21 words

The method of claim 7, wherein an etch-protection layer is deposited on the side walls of said trenches prior to underetching.

Claim 10

Dependent Claim 37 words

The method of claim 2, wherein the layers of said laser structure are separated from said laser substrate by a thin intermediate etch-stop layer, such that the etchant used for underetching does not attack said upper layers.

Claim 11

Dependent Claim 21 words

The method of claim 9, wherein an etch-protection layer is deposited on the side walls of said trenches prior to underetching.

Claim 12

Dependent Claim 41 words

The method of claim 10, comprising a step of depositing at least one of a passivation, antireflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 13

Dependent Claim 56 words

The method of claim 1, wherein said laser structure is mounted on a carrier substrate differing from said laser substrate and in which said step of etching said trenches is continued through said laser structure exposing said carrier substrate at the bottom of said trenches and said step of undercutting is performed in said carrier substrate.

Claim 14

Dependent Claim 81 words

The method of claim 12, wherein a partially-cut pattern is cut at the backside of said laser substrate, said pattern consisting of perpendicular cuts defining rectangular sections, one side thereof being longer than said laser length distance and being parallel to the optic axis of the laser diodes, another side being perpendicular to the said one side such that said substrate of said laser structure or the carrier substrate can be cleaved along these cuts to separate the individual laser diodes.

Claim 15

Dependent Claim 41 words

The method of claim 13, comprising a step of depositing at least one of a passivation, antireflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 16

Dependent Claim 41 words

The method of claim 12, comprising a step of depositing at least one of a passivation, antireflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 17

Dependent Claim 37 words

The method of claim 12, wherein the layers of said laser structure are separated from said laser substrate by a thin intermediate etch-stop layer, such that the etchant used for underetching does not attack said upper layers.

Claim 18

Dependent Claim 41 words

The method of claim 16, comprising a step of depositing at least one of a passivation, antireflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Claim 19

Dependent Claim 21 words

The method of claim 17, wherein an etch-protection layer is deposited on the side walls of said trenches prior to underetching.

Claim 20

Dependent Claim 37 words

The method of claim 12, wherein the layers of said laser structure are separated from said laser substrate by a thin intermediate etch-stop layer, such that the etchant used for underetching does not attack said upper layers.

Claim 21

Dependent Claim 21 words

The method of claim 19, wherein an etch-protection layer is deposited on the side walls of said trenches prior to underetching.

Claim 22

Dependent Claim 41 words

The method of claim 20, comprising a step of depositing at least one of a passivation, antireflection, or protection layer on said cleaved facets before said step of separating said laser diodes and after said step of cleaving said upper portions.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-02-07	1997-08-09	1998-02-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-02-07	2001-08-09	2002-02-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-02-07	2005-08-09	2006-02-08	$7700.00	Window Closed / Lapsed

Full-wafer processing of laser diodes with cleaved facets

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