![©2010 Micron Technology, Inc.
9/11/2010
Micron Confidential
7
Lithographic Performance Evaluation on New Resist:
Focus Latitude of 1.0µm Trench
• Expose conditions:
Substrate: Thermal oxide
Focus: 0µm
DOF [µm]: -1 +1
Exposure: 145 msec
Pitch [µm]: 1L:1S](https://image.slidesharecdn.com/cefe2730-b104-47d8-9d0b-0b58c5819926-150414021955-conversion-gate01/85/Evaluation-of-Modified-GiR-2214-7-320.jpg)
![©2010 Micron Technology, Inc.
9/11/2010
Micron Confidential
8
Lithographic Performance Evaluation on New Resist:
Focus Latitude of 1.0µm Trench
CDSEM images at 145 msec exposure
Isolated Space
Nested Space
-1 -0.5 0 0.5 1
Focus Offset [µm]](https://image.slidesharecdn.com/cefe2730-b104-47d8-9d0b-0b58c5819926-150414021955-conversion-gate01/85/Evaluation-of-Modified-GiR-2214-8-320.jpg)
![©2010 Micron Technology, Inc.
9/11/2010
Micron Confidential
9
Lithographic Performance Evaluation on New Resist:
Focus Latitude of 1.0µm Trench
Side view on Nested structure at
145 msec exposure
Nested Space
-0.5 0 0.5
Focus Offset [µm]](https://image.slidesharecdn.com/cefe2730-b104-47d8-9d0b-0b58c5819926-150414021955-conversion-gate01/85/Evaluation-of-Modified-GiR-2214-9-320.jpg)
![©2010 Micron Technology, Inc.
9/11/2010
Micron Confidential
11
Lithographic Performance Evaluation on New Resist:
Focus Latitude of 0.56µm Trench
• Findings:
~1.5µm DOF process
window around
~550nm nested
space
Minimum resolution
revealed around
400nm
• Expose conditions:
Substrate: Oxide
Focus: 0µm
Mask: Dark field
DOF [µm]: -0.75 +1
Exposure: 185 msec
Pitch [µm]: 1360nm
(1S:1.5L)](https://image.slidesharecdn.com/cefe2730-b104-47d8-9d0b-0b58c5819926-150414021955-conversion-gate01/85/Evaluation-of-Modified-GiR-2214-11-320.jpg)
Evaluation of Modified GiR 2214
- 1. Micron Confidential 9/11/2010 Evaluation of Modified GiR 2214 Photoresist for Low Defectivity I-line Process Boris Kaziev Micron Technology Inc., FAB12, Israel FUJIFILM Advanced Lithography Workshop 2010 ©2010 Micron Technology, Inc. All rights reserved. Products are warranted only to meet Micron’s production data sheet specifications. Information, products, and/or specifications are subject to change without notice. All information is provided on an “AS IS” basis without warranties of any kind. Dates are estimates only. Drawings are not to scale. Micron and the Micron logo are trademarks of Micron Technology, Inc. All other trademarks are the property of their respective owners.
- 2. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 2 • Defectivity study and evaluation Defectivity evaluation at FFEM Black residues Unpatterned defectivity Patterned defectivity reduction work GiR 2214 Resist Evaluation Methodology • Initial conditions definition to supplier Resolution Photospeed Defectivity level • Lithographic performance evaluation on new resist Thickness uniformity and stability Swing curve evaluation Focus and expose latitude review Resolution CD uniformity Thermal stability
- 3. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 3 Initial Conditions Definition to Supplier • Resist performance request I-line low viscosity resist, FT ~1.2µm Low defectivity (primary target) Resolution: CD space ≤400nm on 420S:940L printed as 560S:800L (DF) Fast performance photoresist • Evaluation process conditions Substrate: 200mm Si, HMDS primed Litho Track: SVG-90S Resist: 1.18µm GiR 2214 Soft Bake: 90ºC/90sec (prox.) Exposure: Nikon B12 Stepper Mask: Dark field Illumination: 0.5 NA, σ=0.68 (ID1) PEB: 115ºC/90sec (prox.) Develop: 2.38% TMAH, single nozzle Stream, Single puddle 58ml/60sec Hard Bake: 100ºC/60sec (prox.)
- 4. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 4 • Defectivity study and evaluation Defectivity evaluation at FFEM Black residues Unpatterned defectivity Patterned defectivity reduction work GiR 2214 Resist Evaluation Methodology • Initial conditions definition to supplier Resolution Photospeed Defectivity level • Lithographic performance evaluation on new resist Thickness uniformity and stability Swing curve evaluation Focus and expose latitude review Resolution CD uniformity Thermal stability
- 5. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 5 Lithographic Performance Evaluation on New Resist: Thickness uniformity and stability • Desired: Good coverage with 1.5ml resist dispense using Micron coat recipe • Findings: Complete coverage down to 0.5ml Good and desired resist profile down to 1.1ml Good process window for thickness stability
- 6. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 6 Lithographic Performance Evaluation on New Resist: Swing Curve Evaluation • Conditions: Swing Curve tested on Thermal Oxide substrate CD sampling: 7 points across the wafer (radial) • Findings: Good linear behavior of THK vs. RPM around the desired working point Swing minimum position revealed at 11800A
- 7. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 7 Lithographic Performance Evaluation on New Resist: Focus Latitude of 1.0µm Trench • Expose conditions: Substrate: Thermal oxide Focus: 0µm DOF [µm]: -1 +1 Exposure: 145 msec Pitch [µm]: 1L:1S
- 8. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 8 Lithographic Performance Evaluation on New Resist: Focus Latitude of 1.0µm Trench CDSEM images at 145 msec exposure Isolated Space Nested Space -1 -0.5 0 0.5 1 Focus Offset [µm]
- 9. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 9 Lithographic Performance Evaluation on New Resist: Focus Latitude of 1.0µm Trench Side view on Nested structure at 145 msec exposure Nested Space -0.5 0 0.5 Focus Offset [µm]
- 10. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 10 Lithographic Performance Evaluation on New Resist: Exposure Latitude at 1.0µm Trench • Findings: Almost no Iso. to Nes. Variation in CD Good linear fit around the desired CD
- 11. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 11 Lithographic Performance Evaluation on New Resist: Focus Latitude of 0.56µm Trench • Findings: ~1.5µm DOF process window around ~550nm nested space Minimum resolution revealed around 400nm • Expose conditions: Substrate: Oxide Focus: 0µm Mask: Dark field DOF [µm]: -0.75 +1 Exposure: 185 msec Pitch [µm]: 1360nm (1S:1.5L)
- 12. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 12 Lithographic Performance Evaluation on New Resist: Focus Latitude of 0.56µm Trench • Findings: High DOF of ~1.5µm at ~550nm trench CD F=-0.75µm; CD=510nm F=1.0µm; CD=no F=0.75µm; CD=481nm F=0.5µm; CD=516nm F=0.25µm; CD=535nm F=0µm; CD=545nm F=-0.25µm; CD=543nm F=-0.5µm; CD=539nm
- 13. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 13 Lithographic Performance Evaluation on New Resist: Minimum Resolution at Focus=0µm • Under dose margin: 190ms - 155ms = 35ms (~19%) 230msec 644nm 140msec No 215msec 615nm 200msec 594nm 185msec 545nm 170msec 482nm 155msec 409nm
- 14. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 14 Lithographic Performance Evaluation on New Resist: Critical Dimensions Uniformity • CD variation test groups: GiR 2214 Ref. resist (Resist A) • Test methodology: 5 wafers per group measured; 5 sites per wafer • CD findings for GiR 2214: Better CD uniformity WIW variation is lower by factor of 3 Very low CD range vs. Resist A
- 15. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 15 Lithographic Performance Evaluation on New Resist: Thermal Stability • Variation in Hard Bake temperature FT – 1.2µm on Bare Si Hard bake – 60sec (prox.) • Findings: Stable Pattern remains up to 120ºC GiR 2214 exhibits strong profile degradation at 140ºC No Bake 100ºC 120ºC 140ºC
- 16. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 16 Lithographic Performance Evaluation on New Resist: Evaluation Summary • Good and desired lithographic performance reviewed, without any process modifications • Stable thickness performance and uniform resist profile • High focus and exposure latitude • Minimum resolution of 400nm trench • Highly uniform CD across the wafer • Stable resist profile up to 120ºC
- 17. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 17 • Defectivity study and evaluation Defectivity evaluation at FFEM Black residues Unpatterned defectivity Patterned defectivity reduction work GiR 2214 Resist Evaluation Methodology • Initial conditions definition to supplier Resolution Photospeed Defectivity level • Lithographic performance evaluation on new resist Thickness uniformity and stability Swing curve evaluation Focus and expose latitude review Resolution CD uniformity Thermal stability
- 18. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 18 Defectivity Study and Evaluation: Defectivity Evaluation at FFEM • SP1 and KLA evaluation performed at FFEM/Japan • FFEM investigated modifications to filtration processes, resist processing and resist component (Novolak, PAC etc.) choice in order to achieve the “cleanest” sample to meet Micron’s defectivity targets Formulation Designation SP1 (Part/8” wafer) Avg of 2 wafers KLA Pattern Blob/ Residue D0 (Defect/cm2) Avg of 2 wafers Comments 1 Alternative 1 88 1.14 • SP1 well within Micron target range • KLA is too high for Micron Target 2 Alternative 2 1905 0.51 • SP1 is high • KLA is still high 3 GiR 2214 11 0.06 • Exhibits very low defectivity both for SP1 and KLA 4 Alternative 3 366 1.78 • SP1 is higher than Micron UCL • KLA is high • Similar to previous KLA results at Micron
- 19. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 19 Defectivity Study and Evaluation: Black residues • Location: edge of resist wall • Defects calculation: invisible • Risk: unclear • Profile review: Small undercut at the bottom of the resist Tiny resist residues at this area • Purposed solution: Developer puddle time reduction • Solution limitation: lithography process window and photospeed impact Initial State Lower Puddle Time; higher NA
- 20. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 20 Defectivity Study and Evaluation: SP1 after Coat Defectivity • Findings: Initial state - low defect count for GiR 2214 Filter B implementation by Micron - additional significant defect level reduction • 2 types of filter tested at Micron for new sample: Filter A – Nylon-based filter Filter B – DUO-based filter • SP1 monitor sensitivity is up to 90nm • The results shown are average of 2 wafers each group
- 21. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 21 Defectivity Study and Evaluation: Patterned Defectivity Reduction Work • Patterned defectivity tested using KLA instrument, on Bare Si wafers • Initial Evaluation Process Conditions: Mask – Bright Field; Pitch=2µm (1:1) Resist dispense – 1mL/sec; 1.5mL PEB - 110ºC/90sec (prox.) Develop - Single puddle 40sec • Initial findings revealed 3 types of defects: 1. “Cone shape” like defects – small amount 2. Particles – high amount 3. Resist residues, especially in dense areas Particles Cone shape Residues
- 22. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 22 Defectivity Study and Evaluation: Patterned Defectivity Reduction Work • Initial state: resist defectivity level is very high • Process modification efforts performed at Micron for defectivity reduction Patterned Defectivity Initial Results 0 0.5 1 1.5 2 2.5 3 3.5 4 GiR 2214 Initial state Resist A (ref.) DefectDensity
- 23. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 23 Defectivity Study and Evaluation: Patterned Defectivity Reduction Work • Each result consist of 2 individual tests Combination of • Higher Develop puddle time; • Higher PEB temperature; •Filter type; •Dispense rate (DR) and dispense spin speed (DSS) decrease allow significant defectivity reduction.
- 24. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 24 Defectivity Study and Evaluation: Evaluation Summary • GiR 2214 well meets Micron defectivity requirements • Micron process optimization results: Cone shape defects eliminated Significant reduction of particles Significant reduction of residues • Process optimization contributors: Lower dispense rate -> micro bubbles reduction New filter -> particles amount decrease in the resist Longer develop time -> residues reduction by effective resist dissolving Higher PEB temp. -> residues/particles easier washed off during the develop process
- 25. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 25 GiR 2214 Micron Evaluation Summary • Litho: GiR 2214 resist exhibits high focus latitude performance Minimum resolution request is achieved Good CD uniformity across the wafer The resist answers fast performance requirement • Defectivity: After process modification at Micron GiR 2214 resist met specified requirements for low defectivity resist, both for Patterned and Unpatterned evaluations Black residues risk is defined as minor, but still is unclear • Overall GiR 2214 sample meets Micron targets; further integrated evaluations will be performed
- 26. ©2010 Micron Technology, Inc. 9/11/2010 Micron Confidential 26 Acknowledgments • Mario Reybrouck - FFEM • Diti Enidjer - Micron • Klug Zohar - Micron • Etay Rosenkrantz - Micron • Hadad Itzhak - Micron • Sofer Nirit - Micron • Thomas Sarubbi - FFEM • John Ferri - FFEM • Norihiko Taguchi - FFEM Thank you for your attention