US 12,334,333 B2
Methods for patterning a silicon oxide-silicon nitride-silicon oxide stack and structures formed by the same
Yi-Ren Wang, New Taipei (TW); and Yuan-Chih Hsieh, Hsinchu (TW)
Assigned to Taiwan Semiconductor Manufacturing Company Limited, Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company Limited, Hsinchu (TW)
Filed on Jul. 19, 2022, as Appl. No. 17/867,812.
Application 17/867,812 is a division of application No. 16/715,094, filed on Dec. 16, 2019, granted, now 11,521,846.
Prior Publication US 2022/0351959 A1, Nov. 3, 2022
Int. Cl. H01L 21/02 (2006.01); C23C 16/04 (2006.01); C23C 16/34 (2006.01); C23C 16/40 (2006.01); H01L 21/3213 (2006.01)
CPC H01L 21/0217 (2013.01) [C23C 16/04 (2013.01); C23C 16/345 (2013.01); C23C 16/401 (2013.01); H01L 21/02164 (2013.01); H01L 21/02271 (2013.01); H01L 21/3213 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A structure comprising:
a conductive material portion located on a substrate;
a layer stack including, from bottom to top, a first silicon oxide layer, a silicon nitride layer having a refractive index in a range from 1.88 to 1.95 at 632.8 nm wavelength, and a second silicon oxide layer and located over the conductive material portion; and
a via cavity extending through the layer stack, wherein sidewalls of the via cavity includes first concave sidewalls of the first silicon oxide layer that are adjoined to a top surface of the conductive material portion, straight tapered sidewalls of the silicon nitride layer that are adjoined to a respective top end of the first concave sidewalls, and second concave sidewalls of the second silicon oxide layer that are adjoined to a respective top end of the straight tapered sidewalls.