Studies on the Possibilities of In-Line Die Attach Characterization of Semiconductor Devices

The qualification of the die attach of semiconductor devices is a very important element of predicting the reliability of the package, as the temperature of the chip is strongly affected by the quality of the die attach. This paper describes our latest findings on die attach quality testing of semiconductor devices using short term thermal transient measurements. Using estimates from simulations as well as from measured structure functions of power transistors with known die attach quality we found that cca the first 100ms section of thermal transients is sufficient to draw conclusion on die attach quality. In case of in-line application of the short term thermal transient measurements however, there are different difficulties such as lack of time for K-factor calibration of the individual devices under test. In this paper we describe certain techniques which have been validated on large number of power LEDs with the aim of application in in line testing of die attach quality.