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We will introduce the ultrasonic microscopy observation of semiconductor packages that we conduct. Due to storage conditions and mounting conditions, delamination may occur between the metal parts (die pad) and the package resin in semiconductor packages. Delamination inside the package is a defect that significantly affects product quality, but it cannot be detected from the appearance. By using ultrasonic microscopy, we can clearly capture the internal structure of the package and contribute to reliability evaluation.

Here is an example of observing the adhesive condition through a metal plate using an ultrasonic microscope. An ultrasonic microscope can confirm internal information that cannot be seen from the outside, as long as the ultrasonic waves can pass through. We observed the condition of the adhesive remaining on the metal plate from the metal side in a sample where the chip came off after reliability testing. Please refer to the PDF document for details and results of the observation.

This paper introduces the evaluation of thermally degraded rubber using dynamic viscoelastic measurements. A constant temperature bath capable of circulating air within the chamber was used as a suitable device for thermal degradation testing, and NBR rubber and EPDM rubber were heated at 100°C for a specified duration. The changes in viscoelastic behavior due to heating time were investigated. For both types of rubber, as the heating time increased, tanδ (=E"/E') showed a peak that shifted to the higher temperature side, and a decrease in peak value was observed. It is believed that the loss of rubber elasticity and the decrease in elastic modulus resulted in the shift of Tg to the higher temperature side. By measuring dynamic viscoelasticity, it becomes possible to confirm the changes in physical properties associated with material degradation and to gain insights into structural changes. Additionally, conducting other chemical analyses can clarify more specific changes in chemical structure.