/ Lithography Conventional DRC+Lithographic DRC (Metrology: SEM OPE ) CD-SEM IP CD-SEM Hot Spot 1
DRC: Design Rule Check CD-SEM: Critical Dimension-Scanning Electron Microscope Hot spot: Systematic defect: OPE: Optical Proximity Effect OPC: Optical Proximity Correction OPE bias RET: Resolution Enhancement Technology ED-window: Exposure Latitude-Depth of Focus-Window EPE: Edge Placement Error SEM : SEM AIMS: Aerial Image Measurement System NA: Numerical aperture Die to database PWQ: Process Window Qualification potential defect FOV: Field of View EUV: Extreme Ultra Violet 13.5nm EB: Electron Beam DICD: Development Inspection Critical Dimension FICD: Final Inspection Critical Dimension CD IP: Image Placement 2
0. Systematic defects require new approaches Source: IBS report Error budget OPC Optical Proximity Correction: 3
1. SRAM etc. Cell Layout Std. (Macro) Cell Layout Design rule Preferred Rule Conventional DRC Preferred rule DRC Conventional DRC Preferred rule DRC Cell Characterize Litho. Aware P&R NG Conventional DRC Tape Out RET/OPC/DRC Lithography DRC NG NG Mask Data Processing NG Mask Process OPC DRC Hot spot Solution! OPC/DRC Speed OPC OPC OPE OPC/DRC 4
1-1. CD Focus Budget Nominal condition a (nm) b (nm) c (nm) d (nm) Total f (nm) (DOF) ED- (Exposure lat.) OPC&DRC nominal condition ED-window Hot Spot *CD: Critical Dimension *ED: Exposure latitude-depth of focus Dose Budget o (%) C/D p (%) q (%) r (%) Total d (%) 5
1-2. Hot spot Inter-layer marginal patterns & overlay Intra-layer marginal patterns Hot Spot 6
1-3. OPC&DRC 7
1-4-1. OPE SEM Input Data DesignGauge Output Data Design Data HSS file IN OUT Measurement Result Image Data SEM Image Network Remote Control CD-SEM GDS 100% fail fail classification 8
1-4-2. EPE Design EPE Design Design EPE 2 EPE OPE, OPC OPE, OPC EPE: Edge Placement Error 9
1.5. OPE Lithographic DRC Hot spot OPE SEM CD-SEM OPE SEM 10
Active Beam Steering TR Shutters Selectable Phase Contrast for altpsm Reticle Reflected Illuminator 257 Laser Transmitted Illuminator Imaging Objective Zoom for Selectable Pixels Algorithm Description Application HiRes1 and HiRes2 Litho1 Litho2 TeraFlux Tritone diedatabase High Resolution Images Transmitted Reflected High resolution, high sensitivity MEEF based sensitivity steering Flux based defect detection Phase contrast illumination Uses 2-layer database rendering Ultimate pattern defect sensitivity Defect disposition based on printability Contact hole and via layers Phase defect detection for altpsm Simple tritone mask TDI Imaging Sensor or Die to database NA OPC AIMS-like GDS litho.-sim KLA-Tencor 11
2-2. CD-SEM HV:1.5kV Gun 10-6 Pa SIP1 VF/CL 10-4 Pa SIP2 OL/Det. 10-2 Pa TMP-2 Chamber <10Pa Mask Air Stage negligible G. W. Schlueter, T. Nakamura, J. Matsumoto, M. Seyama, J. M. Whittey, Reticle CD-SEM for the 65-nm technology node and beyond, Annual BACUS Symposium on Photomask Technology and Management, 2004 TMP-1 DryP. 12
2-1. Etching 22% Strip 6% Coating 11% Difficult to repair Type-1 Easy to repair!! Type-2 On Edge On Resist Development 61% Source: 25th Annual BACUS Symposium on Photomask Technology,Volume 5992 2005 22. Type1 Type1 systematic defect OPC 13
2-3. SEM 14
2-4. AIMS (Aerial image measurement system): OPC Carl Zeiss 15
2-5. Die to database NA or SEM CD, OPE, OPC 100% GDS 16
3. Die to Die, Cell to Cell random defect Systematic defect Hot spot PWQ SEM Overlay SEM Critical DICD, FICD CD-SEM 17
3 UBB-capable TDI sensor DUV UV VIS Broadband DUV Blueband GHI-Lines Deepband Midband I-Line G-line UBB spectrum light source Zoom /mag KLA-Tencor 2800 ULTRA-BROADBAND Technologies High speed, scaleable imaging sensor Filters/ND High NA lens High power, ultra-broadband illumination Continuous, high resolution, high NA optics Wafer Die to Die, Cell to Cell PWQ Process Window Qualification Hot spot UP KLA-Tencor 18
3-1-1. -1 PWQ: Process Window Qualification PW ~ 0.15µm in Focus PW < 0.2µm in Focus PW ~ 0.2µm in Focus Nominal condition PWQ Lithographic DRC Hot spot PWQ KLA-Tencor 19
3-1-2. -2 Intel Shift X: 0um Y: +δyum X: +δxum Y: +δyum X: +δyum Y: 0um X: +δxum Y: -δyum Unfiltered IBM Filtered Nominal Shift Unfiltered Filtered X: 0um Y: -δyum X: -δxum Y: -δyum X: -δxum Y: 0um X: -δxum Y: +δyum Horizontal Shift Proceedings of SPIE Vol. 5754, p. 215-255, 2005 Proceedings of SPIE Vol. 5756, p. 51-60, 2005 Proceedings of SPIE Vol. 5754, p. 215-255, 2005 Proceedings of SPIE Vol. 5756, p. 51-60, 2005 EUV PWQ PWQ systematic defect 20
3-2. SEM EIAS Layout data Reference geometry Region to-be-inspected Inspection-unit-area [ STEP1 ] [ STEP2 ] Clipping area corresponding to image to-be-inspected Reference geometry Detected edge Reference geometry Detected edge Bias Profile [ STEP3 ] [ STEP4 ] Intensity Landing energy: 40 to 3000V Probe current : 500pA to 10nA (Verification Mode), 10pA to 1nA (High Resolution Review Mode) Pixel size : 2nm to 20nm FOV per step : up to 200 µm square (0.01% field linearity), 16000 by 16000 pixels Sampling rate : 200 M pixel/sec SEM NanoGeometry Research Inc. 21
3-2-1. Systematic Defect Bridge Space Path Corner Corner End Cap Gate CD NanoGeometry Research Inc. 22
3-3. σ Lithography SEM 23
3-2-2. Litho Simulator ORC vs. Wafer Inspection Defects detected by Wafer Inspection Defects presumed by Lithography simulator A B C Inadequate OPC patterns Inadequate lithography conditions Mask geometry fabrication failure Defects on a mask Inadequate model used in the lithography simulation Litho-DRC wafer inspection SEM GDS or NanoGeometry Research Inc. 24
3-4. Die to Die, Cell to Cell Die to Database PWQ Hot spot EB SEM OPC 25
Computational Lithography (Lithography DRC) Hot spot Systematic defect Lithography-DRC OPE random defect random UP PWQ Hot spot Litho-DRC SEM Systematic defect 26