Latest advancements towards delamination detection in a FCOB assembly using Thermal Pixel (Thixel) array

Latest developments in non-destructive delamination detection using our novel Thixel (Thermal pixel) based array have been reported in our investigations. Four matrices of 5×5 Titanium Thixels were utilized in a solder bump-based flip-chip with a Si die. The flip-chips that were designed and assembled consisted of 2 passivation layers between the chip and solder bumps. The double passivation in this configuration was designed to detect cracking and delamination below the Si die. This process was named Through Passivation Sense (TPS). FCOB concept using an industry-grade flip-chip package was utilized to furnish the proof of concept. The delamination is reflected by the decrease in the measured 3-Omega output voltage of the Thixels. The detected signal change was processed as color coded pixels which hold excellent correlation with the Scanning Acoustic Microscope (SAM) micrographs.