Improved Phase Data Acquisition for Thermal Emissions Analysis

Abstract

This paper describes a 2X improvement in phase data acquisition for Lock-in Thermography (LIT). Phase data is used to generate phase shift versus applied lock-in frequency plots to estimate defect depth in semiconductor packages. Typically, samples need to be tested for an extended time to ensure data consistency. Furthermore, determining the specific point on the thermal emission site to collect data from can be challenging, especially if it is large and dispersive. To overcome these difficulties, new computational algorithms along with streamlined and automated workflows, such as self-adjusting thermal emission site positioning and phase measurement auto-stop, are employed to validate improvements to data repeatability and accuracy as well as faster time to results on different advanced packaging devices such as flip chips and stack dies. Overall, our results showed a 2X faster time to more accurate and repeatable data for X, Y, and Z depth localization.