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The introduction of silver as bonding material led to new failure analysis issues. This study compares the efficiency of wet and dry chemistries for decapsulation on Cu and Ag-based alloy wires. It is shown that dry chemistry allows better control and selectivity on the EMC/ Cu and Ag-based bond wires.

Introduction of Cu and more recently of Ag wires in integrated circuits made the decapsulation more challenging for failure analysts. We made an experiment with the existing techniques we study in the past years and a comparison with the results and the emerging techniques from the last researchs. This study shows that solution has been demonstrated but there is still a place for improvement if we want to have a robust process for all types of ICs.

LASER techniques are widely used for pre-opening in combination with a final manual or automated wet chemistry decapsulation. Even if most of the ICs may be opened today, and if opening the recently introduced Ag wires packages have been solved with novel chemical recipes, the need for a greener and safer solution is still there. Plasma techniques combined with LASER can be a promising solution to these challenges. In this paper, after a presentation of the state of the art of the different techniques available in laboratories nowadays, the latest solution combining LASER and acid or plasma etching is presented. The paper compares the results obtained with these solutions on Cu an Ag wires devices with pros and cons for each solution. The results presented show the benefits, the constraints and the limitations of each technique regarding the different types of wires used in industry.

Copper wires are susceptible to damage during acid decapsulation and must be protected by stopping the process at the right moment. This article describes the development and evaluation of a method that uses polarization current measurements for end-of-etch detection and subsequent rinse.