Bottom-Up Copper Filling of Millimeter Size Through Silicon Vias
This work demonstrates void-free Cu filling of millimeter size Through Silicon Vias (mm-TSV) in an acid copper sulfate electrolyte using a combination of a polyoxamine suppressor and chloride, analogous to previous work filling TSV that were an order of magnitude smaller in size. For high chloride concentration (i.e., 1 mmol/L) bottom-up deposition is demonstrated with the growth front being convex in shape. Instabilities in filling profile arise as the growth front approaches the freesurface due to non-uniform coupling with electrolyte hydrodynamics Filling is negatively impacted by large lithography-induced reentrant notches that increase the via cross section at the bottom. In contrast, deposition from low chloride electrolytes, proceeds with a passive-active transition on the via sidewalls. For a given applied potential the location of the transition is fixed in time and the growth front is concave in nature reflecting the gradient in chloride surface coverage. Application of a suitable potential wave form enables the location of the sidewall transition to be advanced thereby giving rise to void-free filling of the TSV.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE; SPP-funded work
- Grant/Contract Number:
- NA0003525; AC04-94AL85000
- OSTI ID:
- 1490759
- Alternate ID(s):
- OSTI ID: 1492359
- Report Number(s):
- SAND-2018-14027J; /jes/166/1/D3254.atom
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Vol. 166 Journal Issue: 1; ISSN 0013-4651
- Publisher:
- The Electrochemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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