A silicon-based, sequential coat-and-etch process to fabricate nearly perfect substrate surfaces.
For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to approximately 70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize approximately 70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of approximately 470 degrees from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize approximately 70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface.
Lawrence Livermore National Laboratory, Livermore, CA 945550, USA.
P B
PB
Mirkarimi
E
E
Spiller
S L
SL
Baker
D G
DG
Stearns
J C
JC
Robinson
D L
DL
Olynick
F
F
Salmassi
J A
JA
Liddle
T
T
Liang
A R
AR
Stivers
D004563:Electrochemistry; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D049329:Nanostructures; D036103:Nanotechnology / Q000379:methods; D012822:Silicon Dioxide; D013499:Surface Properties; D014466:Ultraviolet Rays
D012822:Silicon Dioxide