Manufacturing experience in reducing environmentally induced failure of laser diodes

Packaged life testing of laser diodes revealed a dramatic degradation of product lifetime. Failure analysis revealed the presence of carbon based compounds deposited on the emission regime causing catastrophic failure. This phenomenon was limited to packaged product. Testing was begun to identify the source, understand the mechanism, and initiate corrective action. Analysis revealed that the epoxy used in assembly was the dominate source of carbon. Contaminated epoxy had been introduced into production by a material batch change at the vendor. It was also learned that deposition only occurred in the dry, oxygen free atmosphere of a hermetically sealed package. It was necessary to develop incoming test procedures and process monitoring to ensure that material of acceptable quality was used. This paper will discuss test methods and results obtained in controlling this failure mechanism.