rapier drie baseline processes drie baseline processes harvard center for nanoscale systems...
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Rapier DRIE Baseline Processes
Harvard Center for Nanoscale Systems
12/17/2014 L. Xie
1
Micro- & Nano-Pillar Etch
L. Xie 2 12/17/2014
Module recipe name: CNS1_Pillars
Sequence recipe name: s_CNS1_Pillars
Module Recipe
Sequence Recipe
• Mask material: photo resist
• Thickness: 0.87 µm
• Diameter: 0.4 µm
Characteristic Achieved
Etch profile 90±0.1°
Scallop depth 10 nm
CD Loss (nm) -70 nm @top
-90nm @bottom
Mask Undercut (nm) 0
Selectivity to resist 11:1
Etch rate 1.56
Uniformity for 6”
wafers
2.5%
Depth (µm) 9.2 µm
Etching mask
12/17/2014 L. Xie 3
Micro- & Nano- Pillar Etch Results
L. Xie 4 12/17/2014
Nano-Trenches Etch
Module Recipe
Sequence Recipe
Module recipe name: CNS2_Nano
Sequence recipe name: s_CNS2_Nano
400nm Zep520A Resist
100nm in width, etched 5 µm in depth
Characteristic Achieved
Etch Profile 89.85
Scallop Depth < 6 nm
CD Loss (nm) 6 nm
Mask Undercut (nm) 0
Selectivity to e-beam
resist
9:1
Etch Rate 1.1 um/min
Uniformity 4.3%
Etch Depth (µm) 5.1
12/17/2014 L. Xie 5
Nano-Trenches Etch Results
L. Xie 6 12/17/2014
High Aspect Ratio Grating Etch
Module Recipe
Sequence Recipe
Module recipe name: CNS3_Grating
Sequence recipe name: s_CNS3-Grating
Characteristic Results
Etch profile
angle
90±0.1°
Scallop depth 38nm @ top
CD Loss (nm) 30nm
Mask Undercut
(nm)
0
Selectivity to
thermal oxide
53:1
Etch rate 1.27
Uniformity 1.3%
Depth (µm) 47 µm
1.0 µm thick thermal silicon oxide etch mask
12/17/2014 L. Xie 7
High Aspect Ratio Grating Etch Results
L. Xie 8 12/17/2014
Micro-Trenches Etch
Module Recipe
Sequence Recipe
Module recipe name: CNS5_Trenches
Sequence recipe name: s_CNS5_Trenches
Characteristic Achieved
Etch Profile 89.8
Scallop Depth < 70 nm
CD Loss (nm) 500 nm
Mask Undercut
(nm)
250 nm
Selectivity to resist 40:1
Etch Rate ~4.0 um/min
Uniformity ~2 %
Etch Depth (µm) 57
5.0µm thick resist etch mask
12/17/2014 L. Xie 9
Micro-Trenches Etch Results
Characteristic Achieved
Etch Profile 90.5°
Scallop Depth < 100 nm
CD Loss (nm) 500 nm
Mask Undercut
(nm)
250 nm
Selectivity to resist 64:1
Etch Rate ~ 7.0 um/min
Uniformity ~2 %
Etch Depth (µm) 92
5.0µm thick resist etch mask
12/17/2014 L. Xie 10
Micro-Trenches Etch Results
Characteristics
• Etch rate depends on lateral dimensions;
• Worst for Chemical reaction limited etching;
• Least for
Ion bombardment limited etching
Higher pumping speed decreases ARDE;
• Oxide often shows reversed ARDE.
50µm 30µm 20µm 10µm
5µm 3.7µm
Aspect Ratio Dependent Etch (ARDE)
12/17/2014 L. Xie
11
Micro-Trenches Etch Results