Simplifying Reliability Testing of Wire Bonds Using On-Chip Heater and Pad Resistance Method

Abstract

In situ sensors can measure wire bond reliability nondestructively during thermal aging. Conventional thermal aging of ball bonds requires ovens heating the entire microchip along with the wire bonds, also affecting interconnects for in situ sensors. To protect the interconnects and on-chip logic components of in situ sensor chips, conventional thermal aging is kept below a safe temperature limit of 200 °C. At higher temperatures, the doped Si components change their characteristics and transistors stop working. Localized on-chip heating is introduced to circumvent these drawbacks using a new microheater to increase the safe temperature limit for nondestructive reliability assessment with in situ sensors. The effect of temperature on surrounding components is reduced. The microheater is a rectangular design resistive heater made from N+ silicon. In addition, a pad resistance measurement is introduced that indicates bond aging more conveniently than previously reported bond resistance measurements.