US 12,211,704 B2
Semiconductor package having side wall plating
Barry Lin, Kaohsiung (TW)
Assigned to Siliconix Incorporated, San Jose, CA (US)
Appl. No. 17/436,429
Filed by SILICONIX INCORPORATED, San Jose, CA (US)
PCT Filed Mar. 8, 2019, PCT No. PCT/US2019/021276
§ 371(c)(1), (2) Date Sep. 3, 2021,
PCT Pub. No. WO2020/185193, PCT Pub. Date Sep. 17, 2020.
Prior Publication US 2022/0172961 A1, Jun. 2, 2022
Int. Cl. H01L 21/48 (2006.01); H01L 21/56 (2006.01); H01L 23/31 (2006.01); H01L 23/495 (2006.01)
CPC H01L 21/4842 (2013.01) [H01L 21/561 (2013.01); H01L 23/3107 (2013.01); H01L 23/49575 (2013.01); H01L 23/49582 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for fabricating a semiconductor package from a package assembly comprising a lead frame comprising a plurality of leads, at least one integrated circuit die mounted on the lead frame, and a mold encapsulation surrounding at least portions of the lead frame while leaving exposed contact surfaces of the plurality of leads, the method comprising:
electrolytically plating the exposed contact surfaces of the plurality of leads of the lead frame to form an electrolytic plating;
making a first series of parallel cuts fully through the lead frame and at least partially through the mold encapsulation to define a first series of sidewalls of the plurality of leads;
making a second series of parallel cuts perpendicular to the first series of parallel cuts, the second series of parallel cuts being fully through the lead frame and at least partially through the mold encapsulation to define a second series of sidewalls of the plurality of leads; and
electrolessly plating the first series of sidewalls and the second series of sidewalls to form wettable flanks by dipping the package assembly in a solution comprising a plating material and applying heat to form an electroless plating on the first series of sidewalls and the second series of sidewalls;
wherein the electrolytic plating has a first thickness, the electroless plating has a second thickness, and the first thickness and the second thickness differ.