US 12,424,453 B2
Low temperature direct copper-copper bonding
Stephen J. Banik, II, Philadelphia, PA (US); Justin Oberst, Beaverton, OR (US); Kari Thorkelsson, Portland, OR (US); Bryan L. Buckalew, Tualatin, OR (US); and Thomas Anand Ponnuswamy, Sherwood, OR (US)
Assigned to Lam Research Corporation, Fremont, CA (US)
Appl. No. 17/309,567
Filed by Lam Research Corporation, Fremont, CA (US)
PCT Filed Dec. 7, 2019, PCT No. PCT/US2019/065111
§ 371(c)(1), (2) Date Jun. 4, 2021,
PCT Pub. No. WO2020/123322, PCT Pub. Date Jun. 18, 2020.
Claims priority of provisional application 62/777,649, filed on Dec. 10, 2018.
Prior Publication US 2022/0018036 A1, Jan. 20, 2022
Int. Cl. H01L 21/48 (2006.01); C25D 3/38 (2006.01); C25D 5/00 (2006.01); C25D 5/02 (2006.01); C25D 5/08 (2006.01); C25D 5/18 (2006.01); C25D 5/48 (2006.01); C25D 7/12 (2006.01); C25D 17/00 (2006.01); C25D 21/12 (2006.01); C25F 3/02 (2006.01); C25F 3/22 (2006.01); H01L 23/00 (2006.01)
CPC H01L 21/4846 (2013.01) [C25D 3/38 (2013.01); C25D 5/022 (2013.01); C25D 5/08 (2013.01); C25D 5/18 (2013.01); C25D 5/48 (2013.01); C25D 5/605 (2020.08); C25D 5/617 (2020.08); C25D 7/123 (2013.01); C25D 17/001 (2013.01); C25D 21/12 (2013.01); C25F 3/02 (2013.01); C25F 3/22 (2013.01); H01L 24/11 (2013.01); H01L 24/13 (2013.01); H01L 24/742 (2013.01); H01L 24/81 (2013.01); H01L 2224/11462 (2013.01); H01L 2224/11831 (2013.01); H01L 2224/11901 (2013.01); H01L 2224/13078 (2013.01); H01L 2224/1308 (2013.01); H01L 2224/13147 (2013.01); H01L 2224/81895 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A method of preparing copper features for direct copper-copper bonding, the method comprising:
forming a plurality of first copper features on a first substrate, each of the plurality of first copper features having nanotwinned copper structures; and
electroplanarizing the plurality of first copper features by anodically biasing the first substrate, contacting the plurality of first copper features with an electrolyte, and electrochemically removing a portion of exposed copper from the first copper features prior to directly bonding the first substrate to a second substrate having a plurality of second copper features disposed on the second substrate, wherein electroplanarizing the plurality of first copper features comprises:
electroetching copper of the plurality of first copper features below a critical potential; and
electropolishing the copper of the plurality of first copper features above the critical potential.