US 11,929,341 B2
Nano copper paste and film for sintered die attach and similar applications
Shamik Ghosal, Waterbury, CT (US); Remya Chandran, Waterbury, CT (US); Venodh Manoharan, Waterbury, CT (US); Siuli Sarkar, Waterbury, CT (US); Bawa Singh, Waterbury, CT (US); and Rahul Raut, Waterbury, CT (US)
Assigned to Alpha Assembly Solutions Inc., Waterbury, CT (US)
Appl. No. 17/255,289
Filed by ALPHA ASSEMBLY SOLUTIONS INC., Waterbury, CT (US)
PCT Filed Jun. 21, 2019, PCT No. PCT/GB2019/051768
§ 371(c)(1), (2) Date Dec. 22, 2020,
PCT Pub. No. WO2020/002890, PCT Pub. Date Jan. 2, 2020.
Claims priority of provisional application 62/689,962, filed on Jun. 26, 2018.
Prior Publication US 2021/0162496 A1, Jun. 3, 2021
Int. Cl. B22F 1/102 (2022.01); B22F 1/052 (2022.01); B22F 1/07 (2022.01); B22F 5/00 (2006.01); B22F 9/24 (2006.01); B23K 35/02 (2006.01); B23K 35/30 (2006.01); H01L 23/00 (2006.01); B82Y 40/00 (2011.01)
CPC H01L 24/29 (2013.01) [B22F 1/052 (2022.01); B22F 1/07 (2022.01); B22F 1/102 (2022.01); B22F 5/006 (2013.01); B22F 9/24 (2013.01); B23K 35/025 (2013.01); B23K 35/302 (2013.01); B22F 2301/10 (2013.01); B22F 2304/054 (2013.01); B22F 2304/056 (2013.01); B22F 2304/058 (2013.01); B82Y 40/00 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A method of forming a joint between two or more work pieces, the method comprising:
providing two or more work pieces to be joined,
providing a sintering paste in the vicinity of the two or more work pieces, the sintering paste comprising a sintering powder comprising copper particles, wherein the particles are at least partially coated with a capping agent, the particles exhibit a D10 of greater than or equal to 100 nm and a D90 of less than or equal to 2000 nm, the sintering powder comprises up to 1 wt. % of the capping agent, and the capping agent comprises triethanolamine,
drying the sintering paste, and
heating the sintering paste to at least partially sinter the copper, wherein the sintering paste is screen-printed onto one or more of the work pieces to be joined to form a screen-printed pattern, and solder is applied to the screen-printed pattern.