Prolith 3.1 Post Exposure Bake PEB PC 1970 F.H.Dill [1-2] PC Aerial Image Image in Resist Latent Image before PEB Resist Profile Develop Time Contours Latent Image after PEB 1
NA PEB [3-4] NA Cr 2 3 (b) 2
3(c) 3 (a) (b) profile Top View Overlap (C) profile 2 3 3.2 CD Swing Curve CD Swing Curve CD Swing Curve 248nm(KrF ) 180nm NA=0.60 =0.85 0.50 Annular Input BARC 62,102,142nm 3
180nm L/S KrF 0.85/0.5 Annular Input: Resist Thickness (BARC Thickness) Output: Resist CD BARC BARC 62nm BARC E0 Eth Swing Curve E0 Eth E0 E0 KrF Swing Ratio=1.82 4
KrF 0.8/0.5 Annular Input: Output: Swing Ratio: 1.82% E0 3.3 Focus-Exposure Matrix Focus-Exposure Matrix 248nm NA=0.6 =0.8/0.5 180nm Bossung 180nm L/S KrF 0.8/0.5 Annular Input: Focus Exposure Output: Resist CD 6 Bossing 5
50mJ/cm 2 10% 80 10% Resist Profile Focus-Exposure Matrix 10% -10% 10% 80 [ ] 6
Process Window CD < 10% Angle > 80 deg. Loss < 10% EL: 10% DOF: 1.57um Best Expo:45.00mJ/cm2 Best Focus:-0.17um -0.17 m 45mJ/cm 2 10% DOF 1.57 m DOF DOF 10% DOF 1.57 m 15% DOF 1.35 m 5% DOF 1.75 m 7
EL vs. DOF DOF CD CD 8
10 CD 3.3 CD BARC BARC 11 9
12 BARC BARC BARC 62nm Si BACR BARC 62nm BARC BARC BARC 62nm Input: BARC Output: BARC 12 BARC 13 CD 10
13 BARC BARC 102nm Swing Ratio 22.7% 62nm 1.85% BARC 1/10 14 14 BARC Si BARC Si BARC BARC 146nm BARC 88nm 0.071% 3.4 NA DOF NA 15 NA DOF NA, DOF NA=0.5 0.8 DOF=1.215 m =180mJ/cm 2 11
Input: NA,, Exposure dose Output: Depth of Focus NA=0.5, =0.8 DOF 15 NA DOF NILS NILS NA NILS 16 NA NILS NA Input: NA, Output: NILS NA=0.69, =0.30 NILS 16 NILS NA NA 17 NA=1.35 ArF 4 35nm 65nm 100nm 6% 12
10nm Unpolarized Azimuthally Polarized DOF Radially Polarized DOF NA Azimuthally Polarized Focus-Exposure Unpolarized Radially Polarized 35nm Lines on 100nm Pitch NA = 1.35, Immersion Cross-Quad Source 6% Attn. PSM 10nm Bias on Mask 17 NA 18 Input:Zernike Coma Output: Placement Error 18 Coma 13
Coma 18 Coma Palcement error 11nm Coma 0.06 3.4 OPC Kirchhoff Kirchhoff 19 d,l PSM OPC Maxwell 19 20 Kirchhoff Maxwell Maxwell 14
Dose 52 PROLITH Kirchhoff Solver Dose 38 PROLITH Maxwell Solver 51 37 50 36 49 35 48 34 47 33 46-0.2-0.1 0.0 0.1 0.2 Focus 32-0.2-0.1 0.0 0.1 0.2 Focus 80nm_160nm 80nm_200nm 80nm_240nm 80nm_320nm Overlap 160P.80.C.3 200P.80.C.3 240P.80.C43 320p.80.C Overlap Results show that Kirchhoff approximation does not comprehend the effect mask structures and pitch imaged with extreme off-axis illumination have on the center of focus, exposure dose and overall process window for these deep-sub-wavelength imaging conditions. In terms of optical-proximity-correction (OPC) the error in the Kirchhoff approximation could be 20% or larger from experimental results and that Maxwell is in good agreement. 20 Kirchhoff Maxwell Maxwell 21 15
21 OPC PEB 16
Mask Aerial Image Image in Resist Resist Profile Latent Image After PEB Latent Image before PEB 22 OPC CSE Critical Shape Metrology OPC ( ) Critical Shape Metrology 23 OPC 17
CSM CSD Input: Serif Size Output: Resist CSE Serif Size CSD 24 CSD CSE 25 CSE 18
25 OPC L=300nm W=50nm NA=1.30 26 ArF OPC 26 19
OPC 27 OPC OPC 3.5 LER CD CD Yield CD Fr eq Input Process errors as gaussian distribution CD distribution 0.3 & Analysis Frequency 0.2 CD spec 300nm +/- 30nm Focus error 0.1 Mean: 303.98nm 0.0 200 220 240 260 280 300 320 340 360 380 400 Resist Feature Width, CD (nm) Std.Dev:13.65nm Yield: 96% Cpk: 0.64 28 20
Example latent image after PEB (left) and resist profile (right) for 29 LER LER LER 3.6 [6]-[9] KLA-Tencor Prolith 21
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