US 11,817,395 B2
Depositive shielding for fiducial protection from redeposition
Sean Morgan-Jones, Portland, OR (US); Mark Najarian, Beaverton, OR (US); Michael Schmidt, Gresham, OR (US); and Victoriea Bird, Beaverton, OR (US)
Assigned to FEI Company, Hillsboro, OR (US)
Filed by FEI Company, Hillsboro, OR (US)
Filed on Sep. 29, 2020, as Appl. No. 17/037,276.
Prior Publication US 2022/0102284 A1, Mar. 31, 2022
Int. Cl. H01L 23/544 (2006.01); H01J 37/305 (2006.01); H01J 37/09 (2006.01); H01L 21/263 (2006.01); H01L 21/285 (2006.01); C23C 16/48 (2006.01); H01L 21/02 (2006.01)
CPC H01L 23/544 (2013.01) [H01J 37/09 (2013.01); H01J 37/3053 (2013.01); C23C 16/486 (2013.01); H01J 2237/3174 (2013.01); H01J 2237/31732 (2013.01); H01L 21/02115 (2013.01); H01L 21/02271 (2013.01); H01L 21/2633 (2013.01); H01L 21/28568 (2013.01); H01L 2223/54426 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A method, comprising:
selecting an area of a substrate that includes a fiducial;
forming a shield on the substrate proximate the fiducial, wherein the shield has a shield height and is situated at a distance of less than two shield heights from the fiducial; and
processing the substrate in a selected area situated so that the shield is between the fiducial and the selected area, wherein the substrate is processed in the selected area by ion beam milling so that the fiducial is protected by the shield during the ion beam milling.