1. Konstantinos Adam and Prof. Andrew Neureuther
Implications of Polarization, Corner Rounding, OPC Design and OPC Fidelity on Aerial Images
SFR Workshop
November 8, 1999
Konstantinos Adam and Prof. Andrew Neureuther
Berkeley, CA
We use EM theory and rigorous TEMPEST simulations to investigate photomask technology issues. Current investigations include scattering bars, polarization effects corners, interior versus exterior OPC features, placement and corner rounding.
5/3/2019

2. Scattering Bar Simulation with TEMPEST
l=193nm
Mag=4X
CDtarget=130nm
|Ey| CD SB
x-axis
z-axis
Incident radiation
y-axis
TE : Ey polarization mm
|Ex|
TM : Ex polarization mm mm
5/3/2019

3. Scattering Bar Aerial Images
l=193nm, NA=0.7, s=0.6, Mag=4X, CDtarget=130nm
Aerial Image (Best focus)
0.1
0.2
0.3
0.4
0.5
0.6
0.8 1
1.2
1.4
SPLAT TE TM
No SB
SB size = 0.18l/NA
Normalized Intensity
(mm)
- Observe that the scatter bars (also the main feature) appear wider in TM excitation than in TE and narrower with SPLAT simulation (scalar theory)
5/3/2019

4. SB Design Graphs Intensity dip of SB CD Control with SB Size Control
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.6
0.8 1
SPLAT TE TM
Perturbation model
0.1
0.2
0.3
110
120
130
140
150
160
SPLAT TE TM
Intensity
CD (nm)
Size of SB (l/NA)
Size of SB (l/NA)
5/3/2019

5. Corner Rounding (Clear Field Mask) - |Ey| Near fields
Square mm
Rounded
l=193nm
Mag=4X
CDtarget=130nm
Eincident (TE)
Eincident (TE)
x-axis
y-axis
5/3/2019

6. Corner Rounding Design Graph
0.04
0.08
0.12
0.16
0.2 2 4 6 8 10
radius of curvature in l/NA
LES increase from reference in nm
Clear field mask
Dark field mask
- LES increase versus radius of curvature is quadratic, i.e. it is proportional to the area missing from the corner due to the roundness
5/3/2019

7. External OPC – |Ey| Near Fields
Example: 0.1l/NA Square OPC and “Mouse Ear” OPC with radius=0.06l/NA
Reference
Square OPC
“Mouse Ear” OPC mm
5/3/2019

8. OPC Design Graph Data for OPC dispaced along the diagonal25
Square OPC 20
“Mouse ear” OPC
Data for OPC
dispaced along
the diagonal 15
LES correction in nm 10 5
0.2
0.4
0.6
0.8 1
1.2
1.4
1.6
1.8 2
x10-3
non-overlapping area in mm2 (1X)
5/3/2019

9. Targeted Opportunities in Photomasks and Optics for 2000-2002
Attenuating phase-shifting masks
high refractive index and physical height of the attenuating material adversely influences light in adjacent areas.
Alternating phase-shifting masks
3D problematical structures - resonate ridges and cross-talk between features inside the photomask.
Phase-shifting mask repair
guidelines for adequate repair - height, slope, river bed, stain.
Optics
role of laser bandwidth in image quality.
high NA thin-film polarization effects.
5/3/2019