Strain Relief of Silicon Carbide Substrates(4H-SiC) by Wet Etching

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Abstract:

Strain relief etching is a critical wet process technique use in high volume manufacturing of semiconductor substrates and device wafers. The goal of a strain relief etch is application dependent but can generally be considered for removal of warp/bow or improving mechanical strength by removing sub-surface damage thereby optimizing yields. Silicon Carbide (SiC) has a high chemical resistance which has blocked SiC wafer manufacturers from using strain relief etching to date. In this work, we demonstrate strain relief etching using an Advanced Chemical Etching (ACE) process of the full wafer surface on commercial grade 4H-SiC wafers and poly-SiC wafers at high etch rates (μm’s/hr) which enable ACE as a production technique. The data shows a 4 times improvement of breakage strength, from 13 to 55N, in laser split wafers. Bow and warp of ground wafers is reduced from 70/250µm to -5/25µm approx. respectively, matching Chemical Mechanical Polished (CMP) wafers which is the industrial method for preparing wafers. Thus showing the potential of stronger, flatter wafers being available for chemical mechanical polishing.

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[1] Yole Développement, Wafer Starts for More Than Moore Applications report, April 2023.

Google Scholar

[2] Moeggenborg K, Kegg T, Parfeniuk C, Stoney T, Quast J. Effect of Surface Damage on SiC Wafer Shape. MSF 2015; 821–823: 545–8. https: //0-doi-org.pugwash.lib.warwick.ac.uk/.

DOI: 10.4028/www.scientific.net/msf.821-823.545

Google Scholar

[3] Yang et al Journal of Manufacturing Processes, Volume 70, , October 2021, Pages 350-360.

Google Scholar

[4] Yang et al. ACS Appl. Mater. Interfaces. 2018.

DOI: 10.1021/acsami.8b19557

Google Scholar

[5] Chang et al. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 15, NO. 3, JUNE 200.

Google Scholar