Transcript Document

ETCH PROFILES IN SOLID AND POROUS SiO2
 Porous SiO2 is being
investigated for lowpermittivity dielectrics
for interconnect wiring.
 In polymerizing
environments with heavy
sidewall passivation,
etch profiles differ little
between solid and
porous silica.
 Position (m)
 Solid
UTA_1102_36
 Position (m)
 Porosity = 45 %
 The “open” sidewall
pores quickly fill with
polymer.
Pore radius = 10 nm
ANIMATION SLIDE
University of Illinois
Optical and Discharge Physics
EFFECT OF PORE RADIUS ON CLEANING
 Larger pores have poor view
angles to ions and thicker
polymer layers.
 Lower rate of cleaning results.
GEM_0204_28
ANIMATION SLIDE
4 nm
16 nm
 Ar/O2=99/1, 40 sccm,
600 W, 4 mTorr
University of Illinois
Optical and Discharge Physics
CLEANING INTERCONNECTED PORES
 Cleaning is
inefficient with
interconnected
pores.
 Higher
interconnectivity
leads to larger
shadowing of
ions.
0%
60%
 Interconnectivity
GEM_0204_29
ANIMATION SLIDE
100%
 Ar/O2=99/1, 40 sccm,
600 W, 4 mTorr
University of Illinois
Optical and Discharge Physics
POLYMER SURFACE STRUCTURES
Animation Slide
 The avalanche exposes the tubules to a burst of hot electrons,
unevenly charging surfaces. Ion fluxes are also uneven.
 Electron density
 N2/O2/H2O =79.5 / 19.5 / 1, 1 atm,
15 kV, 2.5 ns
MIN
GEM_0204_41
 Electron Temperature
MAX
University of Illinois
Optical and Discharge Physics
RESOLVING POLYMER SURFACE STRUCTURES
 The avalanche exposes the tubules to a burst of hot electrons,
unevenly charging surfaces. Ion fluxes are also uneven.
 M+ density
 Charge density
Animation Slide
 N2/O2/H2O =79.5 / 19.5 / 1, 1 atm,
15 kV, 2.5 ns
MIN
GEM_0204_42
MAX
University of Illinois
Optical and Discharge Physics