US 12,113,032 B2
Substrate having undercut portion for stress mitigation
YongIk Choi, Seoul (KR); Chris Chung, Seoul (KR); Michael Leary, Sunnyvale, CA (US); Domingo Figueredo, Jacksonville, FL (US); Chang Kyu Choi, Fremont, CA (US); Sarah Haney, San Jose, CA (US); and Li Sun, San Jose, CA (US)
Assigned to Avago Technologies International Sales Pte. Limited, Singapore (SG)
Filed by Avago Technologies International Sales Pte. Limited, Singapore (SG)
Filed on Feb. 9, 2022, as Appl. No. 17/667,645.
Application 17/667,645 is a division of application No. 16/670,564, filed on Oct. 31, 2019, granted, now 11,276,650.
Prior Publication US 2022/0165685 A1, May 26, 2022
Int. Cl. H01L 23/00 (2006.01); H01L 21/48 (2006.01); H01L 23/13 (2006.01); H01L 23/498 (2006.01)
CPC H01L 23/562 (2013.01) [H01L 21/4857 (2013.01); H01L 23/13 (2013.01); H01L 23/49816 (2013.01); H01L 23/49822 (2013.01); H01L 23/49838 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A substrate, comprising:
a first surface;
a second surface that opposes the first surface; and
a metal layer that is exposed at the first surface, wherein the metal layer comprises:
a curved surface configured to receive solder material, the curved surface having an edge portion that is partially covered by a solder resist material such that an undercut is formed between the solder resist material and the edge portion so as to trap a portion of the solder material within the undercut and on the edge portion of the curved surface at a location past an edge of the solder resist material.