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©2014 SPTS Technologies - Confidential & Proprietary
‘Evolution or Revolution?
Process Solutions for Next Generation MEMS’
SEMI MEMS Technical Seminar, Milan Dr Dave Thomas
Marketing Director, Etch Products
23 September 2014
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Bosch Process – the ‘foundation’ of MEMS
■ What does the future hold for the Bosch process?
■ Semiconductor industry in 1994
■ DRIE product evolution
■ Bosch process technology trends
■ Today’s process capability
■ Feature types
■ Feature sizes
■ Aspect ratios
■ Bow & CD control
■ Sidewall smoothness
■ End-point detection
■ Role of the Advanced Packaging market
■ Competing technologies
■ Conclusions
Contents
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Awarded IEEE Jun-Ichi Nishizawa Medal in Amsterdam in 2014
■ Patented in 1994
■ Licensed to other manufacturers
■ SPTS was the first licensee & shipped the first
etch tool based on the Bosch process in 1995
■ SPTS has shipped ~1100 modules since
■ Total license payments to Bosch (all users)
estimated at Euro12M
Bosch Process – The ‘Foundation’ of MEMS
Franz Laermer (VP Corp Sector Research & Advanced Engineering, Bosch Stuttgart)
Andrea Urban (Senior Expert, Eng Sensor Process Technol Dept, Bosch Reutlingen)
The development of the deep reactive ion etching
process by Franz Laermer and Andrea Urban
revolutionized the micro-electro-mechanical
systems (MEMS) industry by enabling cost-
effective production and proliferation of devices
such as the tiny sensors found in automobile air
bag and anti-skidding systems, as well as in
today’s smartphones and laptop computers.
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ ~20 years on
■ Can the Bosch process continue to adapt to new
requirements?
■ What are the known limitations?
■ What are the competing technologies?
■ Which technology will win?
What Next for the Bosch Process?
Evolution or Revolution?
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Intel released its Pentium processor
■ But most people were still using 286/386
■ I joined Electrotech in 1994
■ 1 computer shared between 8 people
■ 2 e-mail accounts in the company
■ Keeping Fax machines supplied with paper!
Semiconductor Industry in 1994
1994 Today
Feature size 0.35µm ~18nm
DRAM Generation 64Mb 8Gb
Largest wafer 200mm 300/450mm
Metals W plug
Al slab
Cu
Dielectrics SiO2 Low k
Integration Subtractive etch Dual Damascene
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
SPTS DRIE Product Evolution
Rapier
ICP
HDP source
High power sources
‘Single Sources’
High Power ‘Dual Source’
ProNova2
DSi
Pegasus
DSi-v
1995
3.3-5.6µm/min ~2005
26µm/min
Today
35µm/min
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
1994/5
■ Taking advantage of a new
approach
■ Checking what
could/couldn’t be done
■ Focus on automotive
applications
■ Technology was key
■ Cost was second
■ Yields were
low/unimportant
Today
■ How can we make better
products?
■ Discovering new limits
■ Consumer, automotive,
biomedical ….
■ Technology still key
■ Smaller features, higher
ARs, tilt control, CD
control …
■ But Cost also key
■ Higher etch rates
■ Higher productivity
■ Higher yields
Bosch Process Technology Trends
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
MEMS = Shapes in Silicon
High Aspect Ratio
1.6 x 98 µm trenches
~60:1 AR
Smooth walls
<20nm scallops
Through Wafer
Sensors
Microphones
NEMS
50nm features
High Rate
Cavities, Caps,
ink-jets High Aspect Ratio
~0.4 µm trenches
~90:1 AR
SOI
2.5 x 25µm
Low Tilt
<0.1º
Mixed isotropic/
anisotropic
processing
High Aspect Ratio
4 x 160 µm trench/TSV
40:1 AR
Complex shapes
High Aspect Ratio
8 x 180 µm trench/TSV
22:1 AR
High Aspect Ratio
1.5 x 36µm trench
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Unprecedented scaling capability of Bosch etching
Extendibility to nm Scale Features
1µm
spacing
150nm
50nm
10µm spacing
■ Mainstream etch equipment typically confined to 2-3 nodes
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
Smaller Features, Higher ARs
Established
devices
Emerging devices
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ 8 x 180µm (22:1 AR) trench for autofocus device
Profile & Bow Control
Profile ranges
Rapier = ~0.14°
Rapier-cd (avg) = ~0.07°
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
Scallop Control = Smoother Walls
Faster gas switching Modify chemistry
2.7 x 55µm trench
<20nm Sc
10 x 70µm TSV
<30nm Sc
Base
Top
5 x 50µm TSV
~5nm ‘waves’
<20nm Sc <10nm Sc 80 x 500nm trenches
~5nm ‘waves’
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Large operating envelope
■ Applicable to all etches to a stop layer
■ Detection limit <0.05%
Claritas End-point Detection
Etch Chamber
Rapid fluorination
of SiF to SiF4
Unable to ‘see’
SiF*
Claritas Unit
High concentration
of SiF4 cracked to
re-form SiF*
Easily detected
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ MEMS is predominantly a ≤200mm activity
■ SPTS has already shipped 300mm DRIE modules for
MEMS
■ Bridged 2/300mm equipment
■ Currently sized for 200mm wafers
■ 300mm process qualification has started at customer sites
■ Advanced Packaging is predominantly a 2/300mm activity
■ CIS packaging currently transitioning from 200mm to 300mm
■ Other TSV/VR etches are already at 300mm
■ Broad range of DRIE process types have already been
scaled to 300mm
■ No inherent scaling issues
■ Advanced Packaging market has mitigated any risk of
MEMS manufacturers wishing to go to 300mm
DRIE & Wafer Size
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
Bosch/Related Processes for Adv Packaging
Interposer TSV Via Middle TSV
‘Conventional’ TSVs
■ Made 300mm MEMS an enticing proposition
Via Last TSV
Tapered
100 µm diam
No scallops
Via Last TSV
Vertical
50 x 120 µm
<160 nm Sc
20 x 160 µm
<160 nm Sc 10 x 100 µm
<70 nm Sc
5 x 50 µm
<6 nm Sc 50 x 100 µm
<150 nm Sc
20 x 100 µm
<150 nm Sc MEMS TSVs
(Poly or W fill)
8 x 180 µm
<200nm Sc
4 x 160 µm
<50 nm Sc
Via Reveal
Via Last ‘Spacer Etch’
Top
Mid
Base
No oxide
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Wet etching of Si
■ Features governed by preferential etching along crystal planes
■ Only valuable for large non-critical devices
■ Single step dry etching of Si
■ Depth limit 20-50µm
■ Limited mask selectivity of ~20:1
■ Grass in larger features
■ Cryogenic dry etching of Si
■ Interesting to academics
■ Smooth sidewalls
■ Max etch rate 2-3µm/min
■ Not manufacturable (-110°C, PR cracking etc)
■ LASER drilling of Si
■ Unsophisticated hole shapes
■ No selectivity to under-layers
■ New materials
■ Glasses, polymers ….
Competing Technologies
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
■ Bosch process has continued to evolve & meet the
changing/challenging needs of the MEMS market
■ Smaller features, high aspect ratios, CD control,
profile control, end-pointing, higher etch rates ….
■ New materials are growing in importance for MEMS
■ Eg glasses, polymers
■ But Si will remain the dominant material
■ Easy to process
■ Mechanically stable
■ Ease of integration with ICs
■ TSV formation for Advanced Packaging paves the
way for 300mm MEMS
■ Significant customer interest & pull
■ Extendibility of the Bosch process has been
unprecedented in the Semi industry
■ Fundamentally unchanged in 20 years
Conclusions
Evolution wins!
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This presentation and the information contained within it is the property of SPTS Technologies and is confidential. Any duplication, disclosure, distribution, dissemination or copying
of this presentation or its contents or use for any purpose other than that for which it is supplied is strictly prohibited, without the prior written consent of SPTS Technologies. © 2014 SPTS Technologies
Conclusions
Evolution wins!
■ Bosch process has continued to evolve & meet the
changing/challenging needs of the MEMS market
■ Smaller features, high aspect ratios, CD control,
profile control, end-pointing, higher etch rates ….
■ New materials are growing in importance for MEMS
■ Eg glasses, polymers
■ But Si will remain the dominant material
■ Easy to process
■ Mechanically stable
■ Ease of integration with ICs
■ TSV formation for Advanced Packaging paves the
way for 300mm MEMS
■ Significant customer interest & pull
■ Extendibility of the Bosch process has been
unprecedented in the Semi industry
■ Fundamentally unchanged in 20 years