Investigations on partially filled HAR tsvs for MEMS applications

For considerations of stress reduction HAR-TSVs were only partially filled with copper. A comparison was made to ring shaped TSVs (i.e. copper ring with silicon core). Two approaches regarding the way of TSV implementation (before and after wafer bonding/ thinning, resp.) are discussed, concerning process ability and yield aspects. Electrical measurement yield 11 MΩ for a single TSV and 76 MΩ for a 4-point TSV-chain (incl. RDL).