E-beam Defect Inspection of EUV Masks and Wafers

Transcription

1 ** Albany Nanotech, NY USA * Hermes-Microvision, San Jose CA USA *** IBM Microelectronics, Burlington VT USA E-beam Defect Inspection of EUV Masks and Wafers Scott Halle**, Fei Wang*, Ravi Bonam**, Hung-Yu Tien*, Karen Badger***, Emily E Gallagher***, John Qi***, Daniel Corliss**, Derek Tomlinson*, Chiyan Kuan*, Wei Fang*, Jack Y. Jau*

2 Inspection Time Can e-beam Inspection Meet the Challenge? Challenges e-beam Defect size Optical Tolerable defect sizes are less than the minimum feature size and Inspection time increases with decreasing defect sizes

3 Outline e-beam defect inspection for EUV lithography e-beam inspection system Die to Database (D2DB) Mode EUV Mask Defect Inspection EUV Wafer Defect Inspection Print Simulation Conclusion

4 printability e-beam Defect Inspection for EUV Lithography EUV Lithography Challenge No Actinic Inspection No Pellicle e-beam Mask Inspection High Sensitivity for identifying surface defects e-beam Wafer Inspection Potential for identifying phase defects Process defects Post develop wafers provide information on lithographic

5 e-beam Inspection System e-beam column and control SuperNova TM Die-DB Inspection etune ADC Scanning Electron Microscope with software for Die-Die inspection Virtualization SuperNova TM system is used for Die-Database inspection etune Used for Die-Die reinspection ADC workstation: Defect Classification and Data Analysis. Magnetic Lens escan 320xp Wafer Inspection tool explore 5400 Mask Inspection tool Detector Laser Blanker TFE source Wafer/Mask Stigmator

6 Die To Database (D2DB) Mode Design Deviation Absorber Defect Substrate Defect Absorber Nibbles Die-Database (D2DB) inspection can identify systematic and random defects critical advantage over Die-Die (D2D) EUV Mask Inspection can be compared directly to Post OPC Mask data EUV Resist Wafer Inspection can be compared to Post OPC print target data Die-Database method along with auto defect classification provides improved detection over Die-Die

7 Decreasing design defect size EUV Mask Inspection Sensitivity - Hole 32x32nm (1X) Max (30nm) A B C D E F G H Program Defects Pindot OPQ Ext. OPQ Ext. Corner Ext. Pinhole CLR Ext. CLR Ext. Corner Int. detection limit 6nm(1x) Min. (detectable) 10nm D2D 20nm D2D 10nm D2DB 20nm D2DB D2D and D2DB have comparable sensitivity on 32x32nm Hole for defects at 10 and 20nm pixel size

8 Decreasing design defect size EUV Mask Inspection Sensitivity LS 28nm (1X) Max (30nm) Program Defects detection limit 6nm(1x) Min. (detectable) 10nm D2D (Mask) 10nm D2DB (Mask) 5nm D2D (wafer) D2D and D2Db have comparable sensitivity on 28nm HP at 10 and 20 nm pixel size

9 Capture Efficiency (%) Capture Efficiency (%) Comparison of Inspection Results between EUV Mask and EUV Wafer Capture Efficiency Comparison - Column C Design defect size (nm) C OPQ Ext. Mask (nm) Wafer (nm) Capture Efficiency Comparison - Column E E CLR Ext Desing defect size (nm) Mask (nm)

10 Aerial Image Simulation Defect Printability on L/S 28 HP Column A (Clear) 10nm 7nm 5nm Column E (absorber) 10nm 7nm 5nm Column C, G 5nm Column I - 5nm Column X - 22nm Column Y - 15nm Defect printability depends on defect types, resist, and process variations which can effect capture efficiency. Diffused Aerial Image simulation of defects on calibrated computational model on the EUV ADT

11 Capture Efficiency (%) Print Simulation defect size (nm) Comparison of Inspection Results between EUV Mask and EUV Wafer Capture efficiency (%) is the number of captured defects divided by eligible defect number. Mask defect capture efficiency is limited by mask fidelity Wafer defect capture efficiency can be limited by Tool printability for an illumination Resist and process variations Capture efficiency (%) vs. Defect size from print simulation - column I Capture Efficiency (%) Design Defect Size (nm) Print Simulation Defect size (nm) Line edge roughness Capture efficiencies on mask and wafer are comparable and 13nm design defects can be detected at 100% capture efficiency

12 Conclusion Demonstrated e-beam defect inspection for EUV Masks and EUV printed Wafer for both die to die (D2D) and die to database (D2DB) at comparable sensitivity and capture efficiencies. E-beam defect inspection for EUV masks shows capability of <20nm defect size detection on multiple patterns, and identifies a variety of defect shapes and types using automated defect classification system. E-beam defect inspection for EUV resist exposure shows capability down to 10nm defect size detection, at the limit of Alpha Demo EUV Tool printing capability, as shown by wafer print simulation studies.

13 Thank You!