Annealing　process　is　generally　adopted　to　reduce　the　residual　stress　and　stabilize　the　microstructure　of　TSV-Cu　in　IC　manufacturing.　In　this　paper,　the　effects　of　capped　Cu　layer　on　the　protrusion　behaviors　of　TSV-Cu　are　investigated　considering　various　double　annealing　processes.　Higher　protrusions　of　TSV-Cu　with　capped　Cu　layer　are　observed　compared　with　that　of　TSV-Cu　without　capped　Cu　layer.　The　reason　is　that　capped　Cu　layer　impedes　the　elimination　of　grain　boundaries　and　local　misorientation　during　the　first　annealing,　resulting　in　the　remaining　of　larger　amounts　of　atoms　and　higher　energy　in　the　grain　boundaries.　Thus,　it　is　easier　to　induce　protrusion　by　grain　boundary　migration　during　the　second　annealing.　In　addition,　the　capped　Cu　layer　effects　on　mechanical　properties　of　TSV-Cu　under　various　double　annealing　conditions　are　investigated　by　nanoindentation　test.　The　values　of　elastic　modulus　and　hardness　are　generally　higher　in　the　presence　of　capped　Cu　layer.　The　reason　is　also　discussed　and　clarified.　IEEE