Advanced Sample Preparation Techniques for Rescuing Damaged Samples with Cracks, Scratches, or Unevenness in Delayering

Nowadays, physical failure analysis (PFA) technique of delayering by finger polishing is still widely used in FA labs, a method that is direct, simple, and flexible. However, with continuous technology scaling of semiconductor devices, conventional top down polishing method becomes more and more challenging with the increased number of transistors and layer stacks, introducing higher risk of sample damage. Therefore, not only new methods of sample preparation but also solutions for fixing problems are highly desired to cope with the increasing complexity of the modern IC devices. In this paper, advanced sample preparation techniques for rescuing damaged samples with cracks, scratches, or unevenness in delayering are introduced, through three typical rescue cases. These techniques are useful and critical for delivering FA results with high quality and high success rate, especially for those “one of a kind” devices.