May 12, 2017 Robert D. Clark Senior Member of the Technical Staff TEL Technology Center, America, LLC
Welcome to the Atomic Scale Era: New Paradigms and Processes for - - PowerPoint PPT Presentation
Welcome to the Atomic Scale Era: New Paradigms and Processes for - - PowerPoint PPT Presentation
Welcome to the Atomic Scale Era: New Paradigms and Processes for Continued Scaling May 12, 2017 Robert D. Clark Senior Member of the Technical Staff TEL Technology Center, America, LLC TEL TECHNOLOGY CENTER, AMERICA, LLC. LEADING-EDGE
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- Background
- Technology and Scaling Trends
- Patterning Challenges and Approach
- Process technology examples
- New Directions for High K Materials
- New Contact Structures
- Summary
Outline
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Background
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Welcome to the Atomic Scale Era- There’s No Longer Plenty of Room at the Bottom.
Historical and Projected Atomic Feature Sizes (half pitch/0.235 nm/Si atom) in CMOS High Volume Manufacturing. Projected feature sizes are based on Intel historical trend through 14nm manufacturing.
Projected 10nm 10nm Actual* CGP 54 54 MX 43 36 Fin 33 34
*Mistry Intel TMD March 28, 2017
Scaling is Taking Longer… But So Far it is Still Delivering.
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So What Happens When We Run out of Room at the Bottom? We Do What We’ve Always Done: We Go Up
Source: dailymail.co.uk
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Technology and Scaling Trends
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180 130 110 90 65 45 32 22 14 10 7 5 1 10 100 1000 1990 1993 1996 1999 2002 2005 2008 2011 2014 2017 2020
Technology Trend: Going Vertical
Vertical utilization is the key approach towards sub-10nm generation
Resolution Wavelength
i-Line ArF EUV
High AR of DRAM 3D NAND large stack Planar FinFET Nano-wire
immersion
3D Architecture Scaling
KrF
[nm]
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Scaling Trend – Sub-lithographic Patterning
Complex and fine patterning technology is required for further scaling
20 40 60 80 100 20 40 60 80 100
- Min. Metal Pitch (nm)
Contacted Gate Pitch (nm)
SADP SADP SE SAQP EUV SE
N22 N10 N7 N5 Metal Pitch Poly Gate Pitch
193i
N14
Design layout change from 2D to 1D
1 mask 1 mask (SAMP) n masks
Alignment challenge CD challenge
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Technology Trend: Self-(Something) Revolution
Mircea and Hsu MPT Short Course SPIE 2015 Auth VLSI 2014
Younkin SPIE 2015 Self-Aligned Double Patterning Self-Aligned Contact
Säynätjoki 8 May 2012, SPIE Newsroom. DOI: 10.1117/2.1201204.004218
Atomic Layer Deposition Atomic Layer Etching
Kim JES EDL 158, 12, 2011, D710-4 doi: 10.1149/2.061112jes
Self-Aligned Self-Directed Self-Limited
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Patterning Challenges and Approach
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Self-Aligned Multi-Patterning (Example 193i based SAQP)
𝜏𝐹𝑄𝐹 = (𝜏𝐷𝐸−1 2 )2= (1 2)2 = 𝟏. 𝟔 𝒐𝒏
- 1. Grid Litho
- 2. 1st Core Etch
- 3. 1st Spacer
Depo
- 5. 2nd Core
Etch
- 6. 2nd Spacer
depo
- 7. 2nd Mandrel
Pull
- 4. 1st Mandrel
Pull
Adapted from Mohanty and Smith SPIE 2017
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Patterning challenges to EPE
SAQP Line cutting with LELELE Final Pattern
𝐹𝑄𝐹 = 𝑔(CD variation, Pattern OL)
- Mandrel, spacer, cuts
- Traditional sources of CD variation
- Roughness
- Previous Pattern
- Cuts to the grid
- Cuts to each other
EPE control is critical for further extension
(EPE : Edge Placement Error)
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Bottom-Up Lithography Top-Down Lithography
Patterning paradigm towards placement accuracy
The paradigm is expanding to self-alignment and bottom up approach Multiple Patterning Self-Alignment
LEx
Multi color
SAMP
ALD / ALE
Shorter Wavelength
Immersion EUV i-line KrF ArF
Self-Alignment + Self-Assembly
Selective Deposition DSA
Shrink
+ +
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Patterning Challenges and Approaches
Typical Scheme Challenge Potential Approach Grid formation SADP SAQP LER, LWR, local CDU
- Etch smoothing (DCS)
- Spacer reshape
Spacer leaning
- Dep / cure and trim
Cost
- PR mandrel
Cut / Block LEx CD, CDU, CER
- Healing, shrink
Alignment with grid (within layer)
- SAB
Cost and complexity mitigation
- EUV
Via/Contact formation LEx CD, CDU, CER
- Healing, shrink
Alignment with metal lines (inter layers)
- FSAV, SAC, SAGC
Cost and complexity mitigation
- EUV
New process development Atomic level process
- ALE / ALD
Bottom up lithography
- Selective deposition
Self- Something
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Process Technology Examples
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Self-alignment through etch selectivity
Intended Design Conventional approach
(using L/S grid)
Etch selects mandrel Etch selects fill material
A = Mandrel B = Spacer C = Fill material Self-aligned approach
(using three grid colors)
C B A C B B A C B B A C B
self-alignment of cut/block is enabled by SAB, using etch selectivity
SAB (Self-aligned Block)
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EPE margin improvement by SAB
12 12
Conventional SAB
half pitch 36 36 etch etch half pitch
(pitch assumption : 24nm)
EPE margin of hard mask is 3 times relaxed
Lithography OL limit will be covered within the margin Lithography OL is restricted to be within 6nm (regardless of 193i or EUV)
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Gate Stack with 2 hole masks
Self-alignment to gate cap, gate spacer and ILD
Multi-color approach enabling Self-alignment Gate Gate Gate Spacer Gate Spacer Gate Spacer Gate Spacer
Gate cap Gate cap
ILD Gate Gate Gate Spacer Gate Spacer Gate Spacer Gate Spacer
Gate cap Gate cap
ILD GC MD MD GC GC Open
EPE Improvement through Self-Aligned Gate Contact (SAGC)
Adapted from Mohanty and Smith SPIE 2017
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Bottom-up lithography
Selective Deposition DSA < Metal on Metal > < Dielectric on Dielectric >
D M M M M M M
growth
D D D D M M M D D D
growth
D D D D M M M M
growth
D D D D
L/S Pitch Multiplication Hole Pitch Multiplication
Bottom-up lithography enables self-alignment and self-assembly
D : Dielectric M : Metal LKR : Low-k Restoration self-assembly DSA : Directed Self-Assembly
x4 multiplication capable at 30nm pitch x3 multiplication capable at 30nm pitch
Clark AVS 2015
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Selective deposition: Metal on Metal
50nm
106.9nm CD: 46.4nm
6.2nm
W Ru 200nm
EDX mapping X-TEM
Ru 37.7nm 41.7nm
SiO2 W Ru
growth
SiO2 W Ru
growth
Deposition of Ru is demonstrated to grow on W only
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New Directions for High K – Teaching a New Dog Old Tricks
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Selective deposition: Dielectric on Dielectric (Al2O3 on TOX, not on Si)
SPA H plasma effective in suppressing Al2O3 growth up to ~5nm on Si and not on oxides
Si Substrate Treatment:
- HDHD: cyclical deposition and low-temperature
plasma hydrogen (SPA H) treatment
- Sustained H-termination on Si
- Delayed ALD Al2O3 incubation
4-5nm selectivity
10:1 Thickness
HDHD
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Anisotropic atomic layer etching of high K films
BCl3 Ar Plasma 1 cycle
Min Microelectronic Eng. 110 (2013) 457–460 50 40 30 20 10
2 4 6 8
ALE cycle (#) Amount etched (Å)
10 12 14
ER=4Å/cycle Al2O3
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Al2O3 HfO2
Area Selective Deposition by Combining ALD and Etching
ALD High K Dielectrics followed by Anisotropic Etching enables Ultra- Thin ALD Sidewall Spacers
Note: Very good selectivity to SiO2
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Ferroelectric HfZrO
Adapted From: Sonal Day et. al. FCNM 2017 Also See: Sharma et. al. VLSI 2017 accepted - coming to Kyoto in June 5nm TiN/7nm Hf0.2Zr0.8O2/Si + 700 oC 30 sec. PMA
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New Contact Structures
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For Thin Body and Fin Structures MIS contact should have an area advantage over silicide
Paramahans VLSI 2012
Rc = ρc/A Planar Bulk Thin Body/Fin Asilicide > AMIS Asilicide < AMIS
Area Effects – Contacts -Theory
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- Wrap Around Contacts are proposed to provide an area advantage for
Metal/Semi contacts formed within M0
- MIS Contacts and Direct Metal Contacts enable the use of a WAC scheme
– NiPtSi contacts require PVD (poor conformality)
Wrap Around Contacts (WAC)
PFET bottom coated
Wrap Around Contacts
More Info? See “Ultralow Resistive Wrap Around Contact to Scaled FinFET Devices by using ALD-Ti Contact Metal” S.A. Chew et. al.
- Accepted. IITC May 16, 2017 Hsinchu, Taiwan.
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Implant?- Conformal solid source doping by ALD
Successful use of ALD B2O3 to create shallow dopant wells by thermal diffusion into Si
- demonstrated. ALD BN did not diffuse
indicating it could be an in-situ cap layer.
Consiglio ALD 2014 and Consiglio JVSATA 34, 01A102 (2016); doi: 10.1116/1.4928705
Before anneal After anneal
Example Application: Punch through stopper for 14nm FinFET is made by SSD
Natarajan IEDM 2014
B2O3 vs. BN with anneal – B profile
180 160 140 120 100 80 60 20 40 60 80
B2O3 ALD cycles Rs (Ohms/sq)
Anneal N2, 30 secs
900˚ C 1000˚ C
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Summary
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- 3D Architectures and Scaling are Required for 10nm and beyond Scaling
- Meeting the challenge of 3D, EPE, New Devices and Contacts Requires New Process
Technology and Patterning Paradigms
- TEL is working continuously to develop and improve the New Processes needed to
continue scaling beyond the 10nm node and through the next decade.
Summary
NS300Z
TELINDY PLUSTM
TactrasTM VigusTM
Certas LEAGATM
NT333TM
CLEAN TRACKTM LITHIUS ProTM Z CELLESTA
TM-i
Triase+ TM
Robert D. Clark/ TTCA-TFPT / 05122017.01 33
- TTCA R&D, Operations and Equipment Support Teams: Kanda Tapily, Steve
Consiglio, Kyle Yu, Danny Newman, Dave O’Meara, Jeff Smith, Cory Wajda, Gert Leusink
- CNSE: Professor Alain Diebold’s Group – Ferroelectric HfZrO
- Notre Dame: Professor Suman Datta’s Group – Ferroelectric HfZrO
- IMEC: MOL Contacts Team, especially S.A. Chew H. Yu and M. Schaekers –
Wrap Around Contacts
- TEL Japan staff including H. Yaegashi, M. Honda and T. Tsunomura for
support and assistance on patterning and selective deposition materials
- Tokyo Electron America Staff including M. Somervell and B. Rathsack for
assistance on patterning and DSA materials
Acknowledgement
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- Clark, R.D. Materials 2014, 7(4), 2913-2944; doi:10.3390/ma7042913
- Clark, R.D. 2015 American Vacuum Society Fall (AVS Fall 2017) Meeting
- Clark et. al. AVS 2016 International Conference on Atomic Layer Deposition (ALD 2016)
- Thibaut et. al. SPIE Advanced Lithography 2017
- Mohanty et. al. SPIE Advanced Lithography 2017
- Dey et. al. 2017 Conf. on Frontiers of Characterization and Metrology for Nanoelectronics (FCNM)
- Clark et al. MRS 2017 Spring Meeting
- Leusink, G. 2017 Area Selective Deposition (ASD 2017) Workshop
- Chew et. al. 2017 IEEE International Interconnect Technology Workshop (IITC) accepted
- Sharma et. al. 2017 Symposium on VLSI Technology (VLSI 2017) accepted
- Clark et. al. 2017 AVS Atomic Layer Etching (ALE 2017) Workshop accepted