ESH friendly solvent for stripping positive and negative photoresists in 3D-wafer level packaging and 3D-stacked IC applications

摘要

NMP is a commonly used solvent for removing positive photoresist in 3D applications, especially in electroplating and (micro-)bumping. However, the negative photoresists are more and more preferred in these applications. Unfortunately, NMP is inefficient for negative photoresist and it is not considered in Europe as an ESH solvent anymore. In this paper a comparative study was carried out in order to identify a solvent that is ESH friendly and a "one-size-fits-all" solution for stripping negative-tone and thick positive-tone photoresist (2-22 μm) for (micro-)bumping, electroplating and TSV etch applications. The study was performed at tool level.