Failure mechanisms and package reliability issues in optocouplers

Optocouplers are devices that block light in one direction but allow light to pass in the opposite direction which are widely used in long distance signal transmission, pulse amplifying circuits and telecommunication equipment. The unique construction, materials, and interfaces in optocouplers that make their failure modes and mechanisms different. This paper presents a definite and comprehensive research on optocoupler failure mechanisms and package reliability. Package-related failure mechanisms in optocouplers include delamination, bonding wire fracture/wire ball bond fatigue, poor die attach quality, poor bonding, humidity induced corrosion and interface contamination. Furthermore, several precautions for reducing such failures are proposed to improve the reliability which will help manufactures and users to improve optocoupler reliability in an effective manner for various applications.