Semiconductor structure comprising a silver alloy pillar, redistribution layer or via and method of manufacturing it using a cyanide-based plating bath

摘要

A semiconductor structure includes a device (100), a conductive pad (102) over the device (100) and a Ag 1-x Y x alloy pillar (101) disposed on the conductive pad (102). Alternatively, a semiconductor structure (800) includes a device (801), a conductive pad (802) on the device (801), a passivation layer (803) disposed over the device (801) and covering a portion of the conductive pad (802) and a redistribution layer (RDL) (806) including Ag 1-x Y x alloy disposed over the passivation layer (803). Alternatively, a semiconductor structure includes a die (501) including a first surface (501A) and a second surface (501B) opposite to the first surface (501A) and a via (503) passing through the die (501) from the first surface (501A) to the second surface (501B), a Ag 1-x Y x alloy filling the via (503). The Y of the Ag 1-x Y x alloy comprises metals forming complete solid solution with Ag at arbitrary weight percentage (Au and/or Pd) and the x of the Ag 1-x Y x alloy is in a range of from about 0.005 to about 0.25. A method for manufacturing the semiconductor structure includes preparing a cyanide-base plating solution including at least one of KAg(CN) 2 , KAu(CN) 2 , K 2 Pd(CN) 4 , immersing the semiconductor structure into the plating solution, applying an electroplating current density of from about 0.1 ASD to about 1.0 ASD to the semiconductor structure to reduce silver ions, gold ions or palladium ions from the plating solution and forming the Ag 1-x Y x alloy structure (101, 806, 503) on the semiconductor structure.