Download - Flip Chip Technology
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Flip Chip TechnologyFlip Chip Technology
2005/6/16
Kim Dong Hwan
School of Electrical Engineering and School of Electrical Engineering and Computer ScienceComputer Science
Seoul National University, KoreaSeoul National University, Korea
Microwave Device Term Microwave Device Term ProjectProject
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
ContentsContents
• Introduction
• Wire Bonding vs. Flip Chip interconnect
• Flip Chip Process (SSB & MSB)
• Conclusion
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
IntroductionIntroduction• Advancements in the packaging of semiconductor devicesAdvancements in the packaging of semiconductor devices
traditionally use wire bondswire bonds to provide the interconnect from device to substrate or to other devices
• Along with the rapid advances in microwave and millimeter Along with the rapid advances in microwave and millimeter wave subsystem developmentwave subsystem development
a growing interest concerning chip interconnection techniques has developed.
• The importance of quality of these interconnectsThe 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 Flip chip offers advantages over traditional interconnect schemes.schemes.
A smaller overall footprints, better thermal heat transfer
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
• Introduction
• Wire Bonding vs. Flip Chip interconnect
• Flip Chip Process (SSB & MSB)
• Conclusion
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Wire BondingWire Bonding
Bond ribbon
Wire Wire length length
lossloss
[Coplanar Waveguide Model]
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Flip Chip Flip Chip InterconnectionInterconnection
[Gold(Stud) Bumps attached]
[Flip Chip Interconnection of Coplanar MMIC][EM-Simulation Structure for RF test]
MMIC(2mm 50 CPW line)
Motherboard on 20-cm Si w
afer
Bump
CPW SmallSmall
BigBig
Compared to the Bond Wire
0 20 40 60 80 100-40
-30
-20
-10
0
-15
-10
-5
0
Tra
ns
mis
sio
n L
os
s [
dB
]
Re
turn
Lo
ss
[d
B]
Freq [GHz]
Measured Simulated
Ref.Ref. Songsub Song
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Flip Chip Flip Chip InterconnectionInterconnection
Bump Height Bump Height ≥≥ Spacing Spacing
☞ The influence of substrate surface -> negligible
{Bump height ≥ Ground to ground spacing of the transmission lines}
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Flip Chip Flip Chip InterconnectionInterconnection
Return lossReturn loss
Insertion loss
Beyond 100GHz → Below 0.5dB
Flip Chip InterconnectionFlip Chip Interconnection Wire BondingWire BondingVersus
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Proximity Effect in Flip-Chip Proximity Effect in Flip-Chip StructureStructure
[ E-field distribution for a flip-chip
mounted CPW MMIC ]
D
Motherboard
MMIC or Device
[ E-field distribution for a flip-chip
mounted CPW MMIC ]
D
Motherboard
MMIC or Device
Height of flip-chip bump (air-gap)
[ Change rate of characteristic impedance as a function of air-gap for a flip-chip mounted CPW MMIC ]
Air gap (m)C
han
ge
in
Z0
(
% )
50 CPW (D= 80m)
Alumina substrate
~ 3 % change at 20 m
Ref. Sangsub Song, “The Flip-Chip Mounted MMIC Technology using the Modified MCM-D Substrate for Compact and Low-Cost W-band Transceivers”
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Why Flip Chip Why Flip Chip Technology?Technology?
~ 650 m
[ Flip-Chip Bonding Technology ][ Wire-Bonding Technology ]
-strip MMIC
Wire -Bonding
50 ~ 100 m
Via
CPW MMIC
Ground
Flip-Chip Bump
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
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
ComparisonComparison
Flip Chip Technology
Wire Bonding
Technology
Advantages
• 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
Disadvantages
• Additional Equipment• Additional processes• Rework after encapsulation is difficult• Die shrink
• Additional Equipment• Additional processes• Rework is difficult• I/O limitation
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
• Introduction
• Wire Bonding vs. Flip Chip interconnect
• Flip Chip Process (SSB & MSB)
• Conclusion
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
SStud tud BBump ump BBonding onding TechnologyTechnology
[Process flow of the SBB]
[Cross-sectional SEM photograph of the bonding portion by SBB]
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
MMicro icro BBump ump BBonding onding TechnologyTechnology
[Process flow of the MBB]
[Cross-sectional SEM photograph of the bonding portion by MBB]
-To cure the resin
☞ Further requirements for miniaturization and higher frequency operation
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
ConclusionConclusion• The need for smaller packagingThe need for smaller packaging
– Flip chip interconnect process → more compact fashion
• Improved electrical performanceImproved 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
[Flip Chip Bump Connection][Wire connection]
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
References[1] Mark S. Hauhe, “Flip Chip Technology Vendor Overview,”[2] R. Sturdivant, “Reducing the effects of the mounting substrate on the perform
ance 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 Manufact- uring, 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.
Flip Chip TechnologyFlip Chip Technology MMDCLDCL EE SNUEE SNU
Thank you !Thank you !