US 12,243,808 B2
Chip scale package (CSP) semiconductor device having thin substrate
Lin Lv, Shanghai (CN); Shuhua Zhou, Shanghai (CN); Long-Ching Wang, Cupertino, CA (US); and Jun Lu, San Jose, CA (US)
Assigned to ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP, Toronto (CA)
Filed by ALPHA AND OMEGA SEMICONDUCTOR INTERNATIONAL LP, Toronto (CA)
Filed on Mar. 23, 2022, as Appl. No. 17/701,695.
Prior Publication US 2023/0307325 A1, Sep. 28, 2023
Int. Cl. H01L 23/482 (2006.01); H01L 23/29 (2006.01); H01L 23/00 (2006.01); H01L 27/088 (2006.01)
CPC H01L 23/4827 (2013.01) [H01L 23/295 (2013.01); H01L 24/05 (2013.01); H01L 27/088 (2013.01); H01L 2224/05644 (2013.01); H01L 2224/05655 (2013.01); H01L 2924/10253 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A chip scale package (CSP) semiconductor device comprising:
a semiconductor substrate having a front surface and a back surface opposite the front surface of the semiconductor substrate;
a plurality of contact pads attached to the front surface of the semiconductor substrate;
a metal layer stack attached to the back surface of the semiconductor substrate, the metal layer stack comprising a first titanium layer;
a first nickel layer;
a silver layer;
a second nickel layer; and
a metallic layer comprising titanium; and
a compound layer attached to the metal layer stack;
wherein a thickness of the semiconductor substrate is less than or equal to 35 microns;
wherein the first titanium layer, the first nickel layer, the silver layer, the second nickel layer, and the metallic layer are in sequence;
wherein the compound layer comprises
a resin material; and
a filler material;
wherein a coefficient of thermal expansion of the compound layer is less than or equal to 9 ppm/° C.;
wherein a glass transition temperature of the compound layer is larger than 150° C.; and
wherein a bending strength of the semiconductor device measured by a three-point bending test with two-millimeter test span, at 25° C., is greater than or equal to 5 Newton per millimeter in width.