Recent progress in nanoparticle photoresist development for EUV lithography Kazuki Kasahara ab, Vasiliki Kosma b, Jeremy Odent b, Hong Xu b, Mufei Yu b, Emmanuel P. Giannelis b, Christopher K. Ober b a JSR Corporation, b Cornell University 1
Contents 1. Introduction 2. Litho performance improvement study - PAG study - Ligand study 3. Summary 2
Contents 1. Introduction 2. Litho performance improvement study - PAG study - Ligand study 3. Summary 3
NP design Process flow Si wafer NP design and process flow 2~3nm NP coating Inorganic Cores Small molecular size metal oxide Reasonable absorbance of EUV Good etch resistance Organic Ligands Multiple carboxylic acid choices Dispersion in organic solvents NP film PEB Soft bake EUV Exposure Negative tone Nanoparticle photoresist is attractive material due to the very high sensitivity. Mask Development with organic solvent Litho performance Exposed at NXE3300 Exposed at B-MET Sensitivity: 7mJ/cm 2 Resolution: 27nmLS JSR EUVLsymposium 2015 4
Plausible Patterning Mechanism Ligand dissociation w/euv exposure Ligand exchange w/euv exposure Condensation reaction w/euv exposure 1. Ligand exchange, 2. Ligand dissociation and 3. Condensation reaction seems to be occurred in parallel. 5
Contents 1. Introduction 2. Litho performance improvement study - PAG study - Ligand study 3. Summary 6
NP litho improvement concept Target Concept Item Scum improvement Accelerate dissolution at unexposed area Better ligand stability for suppress side reaction Higher dissolution rate PAG application Lower pka ligand application Exposed at NXE3300 Exposed at B-MET Sensitivity: 7mJ/cm 2 Resolution: 27nmLS Scum need to be improved!! 1. Higher dissolution rate PAG application and 2. Lower pka ligand application were investigated for scum improvement. 7
Film Thickness (%) E-beam(JEOL JBX9500) Exposure Result - PAG variation study 1/3 - Resist composition: Zirconium type NP, PAG, Solvent QCM evaluation result Higher dissolution rate PAG 100 Higher dissolution rate - w/ Reference PAG - w/ PAG-A 0 0 20 40 Development Time (s) Reference PAG PAG-A Higher dissolution rate PAG-A definitely showed scum improvement from reference PAG. 8
Film Thickness (%) Higher dissolution rate PAG EUV(B-MET) Exposure Result - PAG variation study 2/3 - Resist composition: Zirconium type NP, PAG, Solvent 100 QCM evaluation result Higher dissolution rate - w/ Reference PAG - w/ PAG-A Dose: 2.9mJ 30nmLS Dose: 6.0mJ 30nmLS 0 0 20 40 Development Time (s) Reference PAG PAG-A PAG-A showed better EUV lithography performance, especially better scum performance, than reference PAG. 9
Higher dissolution rate PAG EUV(B-MET) Exposure Result - PAG variation study 3/3 - Resist composition: Zirconium type NP, PAG, Solvent Reference PAG PAG-B PAG-C PAG-A 5.0mJ, 26nmLS 5.0mJ, 26nmLS 8.0mJ, 26nmLS 8.0mJ, 26nmLS Lower PAG dissolution rate to developer Higher PAG dissolution rate strongly affects NP lithography performance, especially scum, improvement. 10
Lower pka ligand pka EUV(B-MET) Exposure Result - Ligand study - Resist composition: Zirconium type NP, PAG, Solvent Lower pka Ligand-A Ligand-B 8.0mJ, 26nmLS Ligand-A 22.0mJ, 26nmLS Lower pka ligand-b Lower pka ligand-b was tried for suppressing the side reaction. Scum improvement was observed with lower pka ligand-b. 11
Lower pka ligand EUV(NXE3300B) Exposure Result - Current best result at IMEC - 27nmL/54nmP 27nmL/54nmP w/ PAG-A, Ligand-B EUVLsymposium 2015 Session 5: EUV Resist 1 Satoshi Dei, JSR Micro N.V. Resolution data => 21nmL/42nmP 20nmL/40nmP Scum improvement was achieved using PAG and ligand technique. Further improvement study will be continued. 12
EUV Photoabsorption (cm2/gm) Cornell Univ. NP talk in SPIE conference [9776-3] 2/22/2016 1:50pm~ Recent progress in nanoparticle photoresists development for EUV lithography [9779-4] 2/22/2016 2:30pm~ Positive tone oxide nanoparticle EUV (ONE) photoresists From Prof. Ober 2.00E+05 1.50E+05 Atomic Data and Nuclear Data Tables, 54, 181-342 (1993) Mask 1.00E+05 5.00E+04 0.00E+00 O Zn In Ti H C Zr Atomic Number Hf Negative tone Positive tone Tomorrow, Cornell University has 2 talks about nanoparticle photoresists. 13
Summary Cornell Univ. and JSR have started a collaboration work to accelerate NP research. NP scum issue can be improved with PAG or ligand optimization. New metal core study has been started. Nanoparticle photoresists have a great deal of room for EUV litho performance improvement. 14
The authors gratefully thank to, for funding Acknowledgement Prof. Ober, Prof. Giannelis Ober group members for EUV exposure opportunity JSR Micro, Inc. Rama Ayothi for B-MET test support JSR Micro, NV Satoshi Dei for IMEC test support KAUST-CU 15
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Appendix 17
EUV(B-MET) Exposure Result - PAG variation study summary - Resist composition: Zirconium type NP, PAG, Solvent without PAG Reference PAG (Low dissolution rate) Higher dissolution rate PAG PAG-B (Low dissolution rate) 30nmLS PAG-C (High dissolution rate) 5.0mJ, 26nmLS PAG-A (High dissolution rate) 5mJ, 26nmLS PAG-A + Ligand-B 8.0mJ, 26nmLS 8.0mJ, 26nmLS 22.0mJ, 26nmLS PAG strongly affects NP lithography performance. Higher dissolution rate design showed better performance. 18