Low Cost Lithography Solution for Advanced Packaging and Application to Through Silicon Via Process

In this paper, the via-last TSV process using dry film lithography will be presented. Historically we used dry film resist (DFR) for the copper rerouting (via metallization) step only, but here we also tried implementing it for via etching. In the first part of the paper the via-last process flow will be briefly described. Then the copper rerouting 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 how dry film can also be used for silicon deep etching. For process evaluation, various lithography parameters were scanned. Selected dry film resist was tested on demonstrators for dry etching and morphological results will be presented.