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Full Wafer Burn-in of Diode Lasers

IP.com Disclosure Number: IPCOM000109645D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 172K

Publishing Venue

IBM

Related People

Seitz, HK: AUTHOR [+2]

Abstract

With today's laser-diode fabrication processes it is customary to subject the fabricated lasers to a stress treatment prior to their final application. The purpose of this burn-in process is to reach steady-state operating conditions and to eliminate inferior devices. In the conventional (cleaved laser) technology it is general practice to package the lasers prior to the burn-in and the final part-screening procedure. These steps constitute a large part of the cost as it involves much handling of individual parts. The disadvantage is that lasers not meeting the screening criteria after burn-in are already packaged. Introduction

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Full Wafer Burn-in of Diode Lasers

       With today's laser-diode fabrication processes it is
customary to subject the fabricated lasers to a stress treatment
prior to their final application.  The purpose of this burn-in
process is to reach steady-state operating conditions and to
eliminate inferior devices.  In the conventional (cleaved laser)
technology it is general practice to package the lasers prior to the
burn-in and the final part-screening procedure.  These steps
constitute a large part of the cost as it involves much handling of
individual parts.  The disadvantage is that lasers not meeting the
screening criteria after burn-in are already packaged.
Introduction

      In the Full-Wafer Technology developed at IBM the laser mirrors
are produced by etching rather than by cleaving.  The lasers can then
be tested and screened in an automated fashion before dicing is done,
here a non-critical process.  These steps are followed by packaging
and burn-in.  The problem with this sequence is that much handling of
devices is needed before final rejection of inferior devices after
burn-in can be done.

      In this publication we describe how "Full-Wafer Technology" can
be utilized to circumvent these shortcomings.
Detailed Description

      The "Full-Wafer Technology" is made more cost-effective by
performing a "Full-Wafer Burn-In" of all parts prior to "Full-Wafer
Testing."  This way the screening data reflect the final condition of
the part rather than an intermediate one.  In addition, there is no
costly handling of deficient chips involved.

      Since a wafer has several thousand lasers, it is not feasible
to do "Full-Wafer Burn-In" in a "one part at a time" sequence as in
testing.  On the other hand, a contacting head to individually
address all lasers simultaneously is very expensive.  For this reason
a method is suggested to allow simultaneous burn-in with a reduced
pin-count contacting head.  A contact-metallurgy on the wafer is
provided such that many lasers are electrically interconnected into
blocks after the standard "F...