Enabling aMicroelectronic
World®
High Power Packaging: Materials, Design and Analysis Considerations
By Jesse E. Galloway, Ph.D
High Power Packaging: Materials, Design and Analysis Considerations
By Jesse E. Galloway, Ph.D
© 2007 Amkor Technology, Inc. Mar-07,
Packaging Trends
2006 2008
Node
Bus Voltage
Clock Frequency
Transistor Count
Leakage Power (%)
Node
Bus Voltage
Clock Frequency
Transistor Count
Leakage Power (%)
90nm ––––– 60nm ––––– 45nm
1.3V ––––– 1.1V ––––––––– 1.0V
––––––––– 35%/yr increase –––––––
–––––––– 400M ––––––––––– 1000M
28% –––––––– 43% ––––– 58% –
90nm ––––– 60nm ––––– 45nm
1.3V ––––– 1.1V ––––––––– 1.0V
––––––––– 35%/yr increase –––––––
–––––––– 400M ––––––––––– 1000M
28% –––––––– 43% ––––– 58% –
© 2007 Amkor Technology, Inc. Mar-07,
RF Modules PS-fcCSP with Interposer
Cell Phone SiPSCSP
FlashDRAM
Flip-Stack CSP
memoryLogic
MCM Packaging
PBGA FCBGA FCBGA FCBGA
© 2007 Amkor Technology, Inc. Mar-07,
• Memory proximity
• Higher Speed
• Integration of components
• Flexible packaging
• Modular / Scalable
• Multi-function package integration at the Subcon
MCM Benefits
© 2007 Amkor Technology, Inc. Mar-07,
MCM Challenges
• Non-symmetric layout
• Disparity in IC peak temperature limits
• Choosing optimal material sets for all components
• Minimizing package level stress
• Minimizing 2nd level interconnect stresses
• Maintaining low thermal resistances
© 2007 Amkor Technology, Inc. Mar-07,
4W 6W2W 20W
IO
40W 100W 200W
100
400
1000
No Heat Sink Heat SinkPackaging Thermal Design Space
© 2007 Amkor Technology, Inc. Mar-07,
Without Heat Sink
~40%
~60%
Thermal performance primarily function of design:• Ground vias• Ground balls• Size of heat spreader• Flow velocity
© 2007 Amkor Technology, Inc. Mar-07,
<10%
With Heat Sink
>90%
Thermal performance primarily function of design:• Heat sink size• Bond line thicknesses• Thermal interface resistance• Flow velocity
© 2007 Amkor Technology, Inc. Mar-07,
TIM I Material(Conductivity)
02468
101214161820
0 2 4 6 8 10TIM I Thermal Conductivity (W/m/k)
% D
iffer
ence
The
ta ja
No Heat Sink Heat Sink Nat Conv Heat Sink Forced Conv
FCBGABody 35mmDie 9mm
© 2007 Amkor Technology, Inc. Mar-07,
TIM I Material(Parameters)
• Dispensability
• Stability over time at elevated temperature
• Adhesive strength
• Bulk thermal conductivity
• Contact resistance
• Maximum filler size
© 2007 Amkor Technology, Inc. Mar-07,
TIM I Material(Voiding)
• Dispense uniformity• Flow uniformity• Volatiles
© 2007 Amkor Technology, Inc. Mar-07,
PolyimideStandoff
BLT
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0 40 80 120BLT (µm)
Thet
a*A
rea
(C/W
*cm
2 ) Material C Material D
Contact Resistance
Slope = (Bulk Conductivity)-1
TIM I Material(Thermal Resistance)
Bulk conductivity andcontact resistanceaffect Theta jc
Copper
Silicon
TIM
θcu-da
θda-bulk
θsi-da
© 2007 Amkor Technology, Inc. Mar-07,
TIM I Material(Aging)
(Temperature Cycling)
0
5
10
15
20
25
0 500 1000Temp Cycles (0 - 100C)
Material E Material F
% In
crea
se in
The
ta jc
10000
20
40
60
0 500Hours at 150C
% In
crea
se in
The
ta jc
(High Temperature Storage)
Material G
© 2007 Amkor Technology, Inc. Mar-07,
Design Feature(Bare Die Vs. Lid)
TIM II
Silicon
TIM II
TIM I
SiliconLid
Lidded FCBGA
SameθFin
Bare die higher
θHTSNK
Bare die higher
θTIM II
Lidded higher
NAθLid
Lidded higher
NAθTIM I
Sameθdie
CommentBare Die FCBGAq
diedie
die
AkL
diedie
die
AkL
dieITIM
TIMI
AkL
Die
Lid
LidLid RR
Lkln
21
π
dieTIMII
TIMII
AkL
LidTIMII
TIMII
AkL
Die
HTSNK
HTSNKHTSNK RR
Lkln
21
π
Lid
HTSNK
HTSNKHTSNK RR
Lkln
21
π
FinFIN Ah1
FinFIN Ah1
© 2007 Amkor Technology, Inc. Mar-07,
100
105
110
115
40 60 80 100 120TIM Gap Thickness (µm)
Tj,m
ax(C
)Bare DieLid
Body 42.5mmDie 20mm
Cross Over Point
Design Feature(Impact of Including Lid)
Cross over point depends on:•Resistance of TIM•Conductivity and thickness of Lid•Planarity of interfaces
© 2007 Amkor Technology, Inc. Mar-07,
40
50
60
70
80
90
0.5 1.0 1.5 2.0 2.5
Lid Thickness (mm)
Max
TIM
I B
LT (u
m)
0
40
80
120
160
0.5 1.0 1.5 2.0 2.5Lid thickness (mm)
Lid
War
page
(µm
)Design Feature(Lid Thickness)
δΙΙδΙTIM ITIM II
( )IIIIIIJCJCkk ,,, δδθθ =
© 2007 Amkor Technology, Inc. Mar-07,
Design Feature(Proximity of die)
Xo
Tσ=0 (110 – 150°C) → 25°C
© 2007 Amkor Technology, Inc. Mar-07,
Design Feature(Proximity of die)
© 2007 Amkor Technology, Inc. Mar-07,
0.04250.045
0.04750.05
0.05250.055
0.05750.06
0.06250.065
0.06750.07
0.07250.075
0.07750.08
0.0825
2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
Die Spread (mm)
BLT
(mm
)
Outer Die Corner Inner Die Corner Average BLT
2.5 mm Die Spacing
10 mm Die Spacing
Design Feature(Proximity of die)
© 2007 Amkor Technology, Inc. Mar-07,
Design Feature(Proximity of die)
ASIC
MemoryDie
Lateral Heating affected by die spacing
© 2007 Amkor Technology, Inc. Mar-07,
2mm x 2mm hot spot with 10x heat flux
Performance Feature(Impact of TIM I Delamination On Hot Spot)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.5 1.0
Hot Spot Location
Rel
ativ
e Th
eta
JC
adhered delaminated
0.0
0.5
1.0
© 2007 Amkor Technology, Inc. Mar-07,
Materials•TIM I•Flash diffusivity•Adhesion•Thermal resistance•Aging•Warpage
Design•Solder join reliability•Warpage control•Layout•Lid
Analysis•Hot Spot•Warpage•Solder joint reliability•Die interaction
Materials – Design - Analysis
© 2007 Amkor Technology, Inc. Mar-07,
Conclusions
• High power MCMs require low resistance TIMs
• Materials must be stable over time
• Delamination becomes critical issue when hot spots are located near die edge
• Design trade-offs must be analyzed to specify optimal lid design
• Location of MCM die affect maximum junction temperature and BLT
