Laser Decapsulation of Transfer Molded Plastic Packages for Failure Analysis

Decapsulation of plastic packaged components is frequently necessary for failure analysis or product development. Conventional techniques utilize an acid etch process, which is not compatible with copper and other acid-sensitive materials. There is limited ability to alter etch geometry or selectively decapsulate individual circuit elements. Laser ablation using a raster scanned Nd:YAG laser was used for selective decapsulation of temperature sensitive passive components in a PDIP packaged DC-DC converter. Copper welds, nylon insulated ferrite, and polyesterimide insulated magnet wire were decapsulated without damage, allowing failure analysis of a miniature transformer and its associated welded leads.