Transcript 슬라이드 1
Microwave Device Term Project
Flip Chip Technology
2005/6/16
Kim Dong Hwan
School of Electrical Engineering and Computer Science
Seoul National University, Korea
Flip Chip Technology
MDCL EE SNU
Contents
• Introduction
• Wire Bonding vs. Flip Chip interconnect
• Flip Chip Process (SSB & MSB)
• Conclusion
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Introduction
• Advancements in the packaging of semiconductor devices
traditionally use wire bonds to provide the interconnect from
device to substrate or to other devices
• Along with the rapid advances in microwave and millimeter
wave subsystem development
a growing interest concerning chip interconnection
techniques has developed.
• The importance of quality of these interconnects
a large impact on the performance of the entire subsystem,
especially at high frequencies.
• Flip chip offers advantages over traditional interconnect
schemes.
A smaller overall footprints, better thermal heat transfer
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• Introduction
• Wire Bonding vs. Flip Chip interconnect
• Flip Chip Process (SSB & MSB)
• Conclusion
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Wire Bonding
Bond ribbon
[Coplanar Waveguide Model]
Wire length
loss
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Flip Chip Interconnection
Compared to the Bond Wire
Small
MMIC(2mm 50 CPW line)
CPW
Big
Bump
Motherboard
on 20-cm
Si wafer
[EM-Simulation Structure for RF test]
-10
-5
-20
Transmission Loss [dB]
Measured
Simulated
0
0
Return Loss [dB]
[Flip Chip Interconnection
of Coplanar MMIC]
-10
-30
-40
0
20
40
60
Flip Chip Technology Freq [GHz]
80
100
-15
Ref. Songsub Song
[Gold(Stud) Bumps attached]
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Flip Chip Interconnection
Bump Height ≥ Spacing
☞ The influence of substrate surface -> negligible
{Bump height ≥ Ground to ground spacing of the transmission lines}
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Flip Chip Interconnection
Flip Chip Interconnection
Versus
Wire Bonding
Insertion loss
Return loss
Beyond 100GHz → Below 0.5dB
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MMIC or
Device
Height of flip-chip
bump (air-gap)
D
Change in Z0 ( % )
Proximity Effect in Flip-Chip Structure
50 CPW (D= 80mm)
Alumina substrate
~ 3 % change at
20 mm
Motherboard
Air gap (mm)
[ E-field distribution for a flip-chip
mounted CPW MMIC ]
[ Change rate of characteristic impedance as a function
of air-gap for a flip-chip mounted CPW MMIC ]
Ref. Sangsub Song, “The Flip-Chip Mounted MMIC Technology using the Modified
MCM-D Substrate for Compact and Low-Cost W-band Transceivers”
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Why Flip Chip Technology?
CPW
MMIC
m-strip
MMIC
~ 650 mm
Wire Bonding
Ground
Via
Flip-Chip
Bump
50 ~ 100 mm
[ Wire-Bonding Technology ]
[ Flip-Chip Bonding Technology ]
Advantages of Flip Chip Bonging Technology.
Short Interconnection Length Better Electrical Performances
High reproducibility High Yield & Less Tuning
Compact size High Packaging density
Passive components are made in dielectric substrate such as alumina
Ceramics, SiO2 and BCB Low Cost
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Comparison
Flip Chip
Technology
Advantages
Disadvantages
Flip Chip Technology
Wire Bonding
Technology
• High density
• High performance
• Noise control
• Thin profile
• Area array technology
• Small device foot prints
• Self alignment
• Mature Technology
• Infrastructure exists
• Flexible for new devices
• Flexible for new bonding
patterns
• Additional Equipment
• Additional processes
• Rework after encapsulation
is difficult
• Die shrink
• Additional Equipment
• Additional processes
• Rework is difficult
• I/O limitation
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• Introduction
• Wire Bonding vs. Flip Chip interconnect
• Flip Chip Process (SSB & MSB)
• Conclusion
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Stud Bump Bonding Technology
[Cross-sectional SEM photograph
of the bonding portion by SBB]
[Process flow of the SBB]
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Micro Bump Bonding Technology
-To cure the resin
[Cross-sectional SEM photograph
of the bonding portion by MBB]
[Process flow of the MBB]
Flip Chip Technology
☞ Further requirements for miniaturization
and higher frequency operation
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Conclusion
• The need for smaller packaging
[Wire connection]
[Flip Chip Bump Connection]
– Flip chip interconnect process → more compact fashion
• Improved electrical performance
– Reduced interconnect length → lower inductance and reduced signal loss
→ lower power requirements
•
The demands of high frequency applications
– Limitation of the wire interconnect → flip-chip bump connection
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References
[1] Mark S. Hauhe, “Flip Chip Technology Vendor Overview,”
[2] R. Sturdivant, “Reducing the effects of the mounting substrate on the
performance of GaAs MMIC flip chips,” in Proc. 1995 Int. Microwave Theory
Tech. Symp. Dig., Orlando, FL, May 1995, pp. 1591-1594.
[3] Hideki Kusamitsu, et al., “The Flip-Chip Bump Interconnection for Millimeter
Wave GaAs MMIC,” IEEE Transactions on Electronics Packaging Manufacturing, VOL. 22, NO .1, January 1999.
[4] T. Krems, et al., “Millimeter-Wave Performance of Chip Interconnections
Using Wire Bonding and Flip Chip,” IEEE MTT-S Digest. pp. 247-250.
[5] Hiroyuki Sakai., “High Frequency Flip-Chip Bonding Technologies and Their
Application to Microwave/Millimeter-wave ICs,” IEICE TRANS. Electron., VOL.
E81-C, NO. 6 June 1998.
[6] Kiyomitsu Onodera, et al., “Novel Flip-Chip Bonding Technology for W-Band
Interconnections Using Alternate Lead-Free Solder Bumps,” IEEE Microwave
and Wireless Components Letters, VOL.12, NO. 10, October 2002.
[7] Sangsub Song, “The Flip-Chip Mounted MMIC Technology using the Modified
MCM-D Substrate for Compact and Low-Cost W-band Transceivers” IEEE
IMS 2005. Microwave Application Seminars.
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Thank you !
Flip Chip Technology
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