Design specific variation in pattern transfer by via/contact etch ...
Design specific variation in pattern transfer by via/contact etch ... Design specific variation in pattern transfer by via/contact etch ...
CD variation maps: case1 vs case2 Pattern density ∆CD : case 1 ∆CD : case 2 Case 1 Case 2 Via a) b) a) ) ∆ ∆average : case2 / case1 = 1.41 b) ) ) ∆∆ ∆ ∆Max – ∆Min : case2 / case1 = 1.49 Copyright ©2008, Mentor Graphics. 40 CD map full range = 6e -3
OBSERVATION: FIB inspection of 0.26 um via after etching. (a) dense vias; (b) isolated via. Dense vias etch faster than isolated via, i.e. inverse micro-loading effect. Dense vias (a) (b) KV areas � Via etch process optimization was done for regular patterns on test wafer � Employed patterns represent a small part of the entire test-chip design � An etch rate variation caused by microloading is governed by a large-scale pattern density variation – much larger than used patters. This scale is order of magnitude of the mean free path of radical species participating in etch reactions. � A full-chip analysis is required for understanding the real pattern dependency of the etch step SEMbar (1) SEMbar (2) Test-chip SEMbar Copyright ©2008, Mentor Graphics.
- Page 1 and 2: Design Design Design specific speci
- Page 3 and 4: Etch Step in Pattern Transfer Simul
- Page 5 and 6: Effects of Aspect Ratio & Microload
- Page 7 and 8: • Neutral radical generation •
- Page 9 and 10: Mass-balance Differential equation
- Page 11 and 12: Radical Flux to the Feature � Whe
- Page 13 and 14: Die-level analysis: Calculation of
- Page 15 and 16: Thin & Thick Polymer Regimes T. Tat
- Page 17 and 18: Approximation of “Thin Polymer”
- Page 19 and 20: Etch Stop Condition � Etch stops
- Page 21 and 22: VCE Input/Output Copyright ©2008,
- Page 23 and 24: Calculation of Gas Kinetic Paramete
- Page 25 and 26: Calibration Methodology � The maj
- Page 27 and 28: VCE Capability Based on accurate ca
- Page 29 and 30: VCE Capability Across-die etch hot-
- Page 31 and 32: APPLICATIONS of VCE Copyright ©200
- Page 33 and 34: Process-Aware Design Optimization v
- Page 35 and 36: Process optimization • VCE predic
- Page 37 and 38: F Concentration, mass fraction Redu
- Page 39: Averaged pattern density R=1000µm
- Page 43 and 44: CF2 flux F flux SEMbar (1) in all01
- Page 45 and 46: Calibration/Prediction - Resist Mod
- Page 47 and 48: Calibration/Prediction - Main Etch
- Page 49: Mentor Graphics Corp., San Jose, CA
CD <strong>variation</strong> maps: case1 vs case2<br />
Pattern density ∆CD : case 1<br />
∆CD : case 2<br />
Case 1<br />
Case 2<br />
Via<br />
a) b)<br />
a) ) ∆ ∆average<br />
:<br />
case2 / case1 = 1.41<br />
b) ) ) ∆∆<br />
∆ ∆Max<br />
– ∆M<strong>in</strong> :<br />
case2 / case1 = 1.49<br />
Copyright ©2008, Mentor Graphics.<br />
40<br />
CD map full range = 6e -3
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