Cost effective dry lithography solution for through silicon via technology

In this paper, an original way to open buried contact in TSV via-last process using dry film lithography will be presented. This approach may solve at the same time issues on either non tapered vias and sloped vias technologies. In the first part of the paper the via-last process flow and the technological issues will be briefly described. Then the contact opening lithography using dry film will be presented. This includes mask design, process parameters and morphological characterization. In the third part of the paper, we will show some results and characterization of the contact etching step. For process evaluation, this brick was implemented in our CIS wafer level packaging process flow and some electrical test were performed.