Transcript Flexible Printed Wiring Board - Forsiden

Chapter 8: Hybrid Technology
and Multichip Modules
Hybrid =
mixture, i. e.:
Components
and wiring
integrated on
the substrate.
Picture shows
a thin film
hybrid for
seismic
electronics.
The course material was developed in INSIGTH II, a project
sponsored by the Leonardo da Vinci program of the European Union
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 1
Types of Hybrids and
Multichip Modules
• Thick film technology
– High temperature thick film hybrid technology
– Polymer thick film hybrid technology
• Thin film technology
– Conventional thin film technology (one conductor layer)
– Multilayer thin film technology
• Multichip modules:
– Multilayer ceramic (MCM-C) (C for ceramic)
– Multilayer thin film (MCM-D) (D for deposited)
– Multilayer fineline circuit boards (MCM-L) (L for laminated)
• Please also confer to Chapters 3 and 5 for basic
processes
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 2
High Temperature Thick Film
Technology
• Important substrate properties
–Dimensional stability
–Good adhesion
–High thermal conductivity
–Thermal compatibility with components
–High electrical resistivity
–Low dielectric constant (not satisfied in
alumina)
–Low dielectric loss tangent
–Good machinability (not satisfied in ceramics)
–Low price
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 3
Screen Printing and Stencil Printing
• Fig. 3.11: Screen
printing:
a) and b): Printing
process,
c) and d): Details of the
screen
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 4
High Temp Thick Film, continued
• Practical
materials:
– Alumina
– Aluminium
nitride
– (Beryllia)
– (Silicon
carbide)
Material
Al2O3 ceramic
(99.5% pure)
Al2O3 ceramic
(96% pure)
Sapphire
Table 8.1:
Properties of
substrate materials
for hybrid
technology.
P: Plastic
In: Insulator
Dielectric
Loss
Relative Factor
permit- (at 10
ivity
GHz,
r
25°C
tan 
Specific Linear
Thermal Thermal
Conduct- Expansion
ivity Kth Coefficient
[W/cm (at 25°C
l/l/T
°K]
[10-6/°K]
Temperature
Coefficient
of 
Type Remarks
T
[10-6/°K]
9,8
0,0001
0,37
6,3
+136
9,4
9,4; 1,6
0,001
0,0001
0,35
0,42
6,4
6
0,0001
0,0036
0,017
0,012
0,55
4,6
Quartz glass
3,78
Corning glass
5,75
Beryllium oxide
Ceramic (BeO) 6,3
(98%)
Semi-Insulating
GaAs
12,9
(High-resistive)
Silicon
11,9
(=103 ohm cm)
PTFE
2,1
Polyolefin (Glass
reinforced)
2,32
PTFE
2,55
Aluminium
Copper
Invar
+110
+140
+13
+107
In
In
-In
In
In
0,006
2,1
6,1
0,002
0,46
5,7
Semi
0,015
1,45
4,2
Semi
0,0003
0,002
106
+350
P
0,0007
0,001
0,005
0,003
2,2
3,93
108
16-100
23,8
17
1,5
+480
P
P
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Anisotropic
In
Dust is
poisonous
For
comparison
Slide 5
Conductor Materials
• Composition
–Functional element (metal particles)
–Binder (glass particles)
–Solvents
• Desired properties
–High electrical conductivity
–Good adhesion to substrate
–Good solderability
–Good bondability
–Low price
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 6
Conductor Materials, continued
Comparison of Parameters for Thick-film Conductors
• Practical
AgPd
Cu
Resistivity (mohm/)
25
1,8
functional Sheet
Breakdown Current (mA/mm width) 3000
10000
10-20
15-30
element Thickness
Minimum With (µm)
150
150
–Gold
–Ag/Pd
–Ag/Pt
–Copper
Through-hole Diameter
Number of conductor layers
Substrate Area (cm2)
Substrate Thickness (mm)
0,4-1,5
1-3
0,2-100
0,6-1
0,4-1,5
1-5
0,2-200
0,6-1
Tin-Lead Soldering Properties on Thick Film Conductors
Parameter
AgPd
Cu
Solderability
Good
Good
Wetting
Good
Good-excellent
Leach Resistance
Fair-good
Excellent
Adhesion
Excellent
Excellent
Visual Quality
Good
Excellent
Au
2,5
10000
5-15
50
1-5
0,2-50
0,25-1
Au
Unsolderable
-
Table 8.2 Properties of thick film conductor systems
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 7
Thick Film Resistors
• Important properties
–Large range of resistor values
–High stability
–Low thermal coefficient of resistivity
–Low voltage coefficient of resistivity
–Low noise
• Materials
–Oxides of ruthenium
–Oxides of iridium, rhodium, osmium
–Sheet resistance: 1 - 109 ohms/sq
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 8
Properties of Thick Film Resistors
Tolerances as fired
Tolerances, laser trimmed
TCRs:
5 to 100K ohm/sq (-55° to 125°C)
100K to 10M ohm/sq (-55° to 125°C)
Resistance drift after 1,000 hr at 150°C
no load
Resistance drift after 1,000 hr at 85°C
with 25 watts/in2
Resistance drift, short term overload
(2.5 times rated voltage)
Voltage coefficient
Noise (Quan-Tech):
At 100 ohm/sq
At 100 Kohm/sq
Power ratings

±0.5 - ± 1%
±100 - ±150 ppm/°C
±150 - ±750 ppm/°C
+0.3 to -0.3%
0.25 to 0.3%
<0.5%
20 ppm/(V) (in)
-30 to -20 dB
0 to +20
40-50 watts/in2
Table 8.3: Typical properties of thick film resistors.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 9
Termination of Thick Film
Resistors
Fig. 8.2: Thick film resistor with termination
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 10
Insulators / Dielectrics
• Desired properties:
–High insulation resistance
–High breakdown field
–Low dielectric constant (insulation)
–Suitable/high dielectric constant (dielectric)
–Low temperature coefficient (dielectric)
–Low voltage coefficient (dielectric)
–Low loss tangent
–Little porosity
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 11
Insulators / Dielectrics,
continued
• Materials
–Aluminium oxide/glass (insulator)
–Ceramics/glasses as for capacitors
(dielectric)
–Please also see Chapter 4
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 12
Insulators / Dielectrics,
continued
Capacitor
Capacitance Absolute
range
Tolerance
[%]
Thick-film I 2 pF/mm2 5 - 20
Thick-film II 8 pF/mm2 10 - 30
Thick-film III 50 pF/mm2 10 - 30
Thick-film IV 150 pF/mm2 10 - 30
Ceramic-chip 1 p F - 4 nF 1 - 10
NPO
Ceramic-chip 0.1 - 1.5 nF 3 - 20
X7R
Tantalum-chip 0.1 - 100 µF 5 - 20

Isolation
Resistance
[Mohm]
12
>106
50
>104
500 >104
2000 >103
10
>105
Tan  TCC
[%]
<0.25
<1.5
<2.0
<4.0
<0.1
[ppm/°C]
45
500
2000
-400
±30
50-200
50-200
50-200
50-200
50-200
1200 >105
<2.5
800
50-200
Maximum <6.0
leakage
current
0.5 - 3 µA
500
4 - 50
25
Voltage
Range
Table 8.4: Typical properties of printed and
discrete capacitors.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 13
Production Process for High
Temperature Thick Film Technology
• Layout and photolithographics
–CAD work
–Photo or laser plotting of master films
–Printing screens made with master films
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 14
Production process, continued
• Printing process
–Printing
–Drying at 100 - 150 °C
–Firing at 700 - 1000 °C
Fig 8.1: Typical
temperature profile
for thick film
firing.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 15
Production process, continued
•Testing and laser trimming
–Initial value targeted 20 - 30 % below specified value
–Laser trimming to increase resistance within ± 0.5 or ±
1.0 %
Fig. 8.4: Probe card for testing of thick- and thin film hybrid
circuits. Coaxial probes are used for high frequency signals.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 16
Laser trimming
a)
b)
c)
Fig. 8.5: Laser trim cut forms:
a): L-cut, the most common
b): Top hat plunge cut
c): Digital trimming, which is most used for high precision thin film
resistors
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 17
Laser trimming, continued
Fig. 8.6: Laser trimmer for thick film hybrid circuits, ESI Model 44.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 18
Production
process,
continued
Fig. 8.7: Process flow for
mounting of thick film
hybrid circuits based on:
a): Naked ICs and gluing of
discrete components.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 19
Production
process,
continued
Fig. 8.7: Process flow
for mounting of thick
film hybrid circuits
based on:
b): Soldering of
packaged ICs and
discrete components.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 20
Polymer Thick Film Technology
• In polymer thick film
hybrid technology (PTF)
conductors, resistors and
insulating layers use a
polymer matrix instead
of glass matrix, and
these are made in several
layers on ordinary
printed wiring board
laminates, flexible
substrates and injection
moulded plastic
materials that can serve
as combined printed
circuits and chassis.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 21
Polymer Thick Film, continued
• Advantages
–Low price
–Simple processes
–Fast production throughput
–Well suited for repair/modification
–Printed resistors possible
–Additive technology
–Printed wiring boards for
substrates
–Specialities:
• Membrane switch panels
• Contacts
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 22
Polymer Thick Film, continued
• Limitations
–Satisfies only moderate environmental
requirements
–Low/moderate complexity
–High sheet resistivity in conductors
–Special design rules
–Limited solderability
–Limited shelf life for pastes
–Limited availability
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 23
Polymer
Thick Film,
continued
Fig. 8.8: Polymer Thick
film (PTF) carbon
technology, for:
a): Keyboard contacts.
b): Contacts of LCDdisplays.
c): Sliding
potentiometer.
CPTF means carbon
type PTF.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 24
Polymer Thick Film, continued
• Materials
–Matrix: Thermosetting /thermoplastic polymer
–Conductor: Ag, Cu, C
–Solvents
–Additives to adjust consistency
• Ceramic or other additives
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 25
Polymer Thick Film, continued
• A typical process
–The starting material is a laminate with a single sided
etched conductor pattern in Cu foil
•
•
•
•
•
•
•
•
•
•
•
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Cleaning of the board
Printing of PTF insulation layer, 2 prints, drying in between
Drying
UV curing
Printing of PTF conductor
Drying
Curing in IR in-line furnace
Chemical plating of metal (Optional)
Printing of top layer
Drying
Curing in IR furnace.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 26
Polymer Thick Film, continued
Fig. 8.9: Membrane switch panel, principle.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 27
PTF,
continued
Fig. 8.10: PTF based printed
wiring boards:
a): Single sided board with PTF
for one complete conductor layer
on top of one Cu foil conductor
plate.
b): Double sided, through hole
plated board with one extra PTF
conductor layer on each side.
c): Double sided board through
hole printed PTF conductor,
instead of through hole plating.
d): PTF resistor
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 28
Thin Film Technology
• Substrate materials
–Alumina, glass, silicon
• Conductor materials
–Gold, aluminium
• Resistor materials
–NiCr (Chrom nickel), Ta2N (Tantal nitride)
• Insulation/dielectrics/passivation
materials
–SiO2 (Silicon dioxide), SiN3 (Silicon nitride),
Al2O3 (Aluminium oxide), Ta2O5 (Tantal oxide)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 29
Thin Film Technology,
continued
Material
NiCr
(nickel-chrome)
Cr (chrome)
Ta (tantalum)
Ta2N
(tantalum-nitride)
Ti (Titanium)
Cr-SiO Cement
Specific
Surface
Resistance
(t<<
Rf = / t
(in ohm)
Temperature
Coefficient
of the
resistance,
Stability
R/(R T)
R/(R T)
(in 10-6/°K) (in %/1000h)
Production
method
40 - 250
10 - 500
40 - 200
-100 - +100
-300 - +300
-200 - +200
<0,2 good
medium
<1 medium
Evap
Evap
Sp
10 - 100
5 - 2000
500 - 2000
-60 - +30
-500 - +500
-250 - +250
<0,2 good
medium
<0,5 medium
Reactive sp
Evap
Flash sp
Table 8.5: Properties of thin film resistors.
(: skin depth. Evap: Vacuum evaporation. Sp: Sputtering)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 30
Thin Film
Processing
• Photolithography and
etching
• Vacuum evaporation
• Sputtering
• Plating
• Oxidation
Fig. 8.11: Process flow for
production of thin film
hybrid circuits.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 31
Vacuum Deposition and Sputtering
• Vacuum
evaporation:
–Chamber
evacuated to
less than 10-6
Torr
–Resistance
heating
–Metal
evaporation
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 32
Other Methods for Deposition of
Conducting or Insulating Films
• DC Sputtering (Fig. 3.13.a)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 33
Deposition, continued
• Radio Frequency AC Sputtering (Fig.3.13.b)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 34
Thin Film Processing, continued
Fig. 8.12 : Structure of thin film resistor with gold
termination.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 35
Thin Film Processing, continued
Fig. 8.13: Thin film microwave circuit, schematically.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 36
Thin Film Processing, continued
Fig. 8.14:
Thin film
transistors,
structure.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 37
Thin Film Processing, continued
• Circuit production
• Glueing
• Wire bonding
• Testing
• Packaging in hermetic (metal) box
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 38
Wire Bonding
• Ultrasonic
• Thermocompression
• Thermosonic
• Geometry Types
–Ball - wedge:
Shown in
illustration
–Wedge - wedge
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 39
What are Multichip Modules?
A multichip module (MCM) is a single unit
(“package”) containing two or more chips
and an interconnection substrate which
function together as a system building
block.
MCM-L
MCM-C
MCM-D
From: http://www.aws.cit.ie/research/wirelessnodes/index.htm
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 40
Types of Multichip Module Substrates
3 basic multichip modules:
MCM-D deposited thin-film multilayers
(D for deposited)
MCM-C thickfilm or cofired ceramic
technology (C for ceramic)
Pictures from:
http://www.aws.cit.ie/researc
h/wirelessnodes/index.htm
MCM-L based on organic laminate technology
(L for laminated)
derived from conventional PWB technology
(also known as chip-on-board, COB)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 41
Multilayer Thin Film – MCM-D
• Process
–1. Spinning polyimide insulation
–2. Deposition Al metallization
–3. Photolithography, wet etch
–4. Spinning polyimide
–5. Etching vias
–6. Repetition steps 1 - 5
–7. Metallization and etching of metal
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 42
MCM-D, continued
Fig. 8.15 a): AT&T´s structure for multilayer thin film. Please also
see also Figure 2.13.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 43
MCM-D, continued
Fig. 8.15 b): Cross section of Raychem´s High Density
Interconnect (HDI) schematically and observed through
microscope.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 44
MCM-D, continued
Fig. 8.16: Elements of the design rules for
Raychem´s HDI technology
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 45
MCM-D, continued
Fig. 8.17:
Character
istic impedance
for Raychem´s
HDI as function
of the ratio
between
conductors
width and
dielectric
thickness.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 46
MCM-D, continued
Fig. 8.18a): Dissipation factor for Raychem´s HDI
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 47
MCM-D, continued
Fig. 8.18. b):
Typical
attenuation, as
function of
frequency, for
Raychem´s HDI.
Even at 10 GHz
attenuation in
the conductor
metal dominates.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 48
MCM-D, continued
• Advantages
• Optimal thermal match when Si
substrate
• High thermal conductivity in Si: 150 W/°C x m
• Termination resistors and decoupling capacitors
integrated in substrate
• Compatibility with:
– Wire bonding
– TAB
– Flip chip
•
•
•
•
Very high conductor density/package density
Very good high frequency properties
Good mechanical properties of Si substrate
High reliability
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 49
MCM-D, continued
• Disadvantages:
–Low availability and high cost
–Polyimide is hygroscopic
–Important properties change
–Reliability problems
–Hermetic encapsulation necessary
–Immature technology
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 50
Multilayer Ceramic Modules
- MCM-C
• Materials
–Alumina
–Aluminium nitride
• Pioneer: IBM
• Fabrication: Green Tape process
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 51
MCM-C, continued
Fig. 8.19: Production process for multilayer ceramic, schematically.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 52
MCM-C, continued
• Advantages
–High thermal conductivity
–Low TCE, match to Si, GaAs, SMDs
–Compatible to flip chip, wire bonding, TAB,
SMD soldering
–Control over characteristic impedance
–Hermetic encapsulation possible, high
reliability
–Many conductor layers, high yield
–Edge contacts, etc. brazed on
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 53
MCM-C, continued
• Disadvantages
–Low electrical conductivity in inner layers
(Rsq ~ 15 mOhm/sq)
–High dielectric constant, r ~ 9 - 10
–High startup cost for custom specific circuits
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 54
MCM-C, continued
Fig. 8.20:
Combination
of naked chips
in cavities and
soldered,
packaged
SMD
components on
multilayer
ceramic
module
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 55
MCM-C, continued
Fig. 8.21.a: Characteristic impedance for typical geometries and
dimensions, Al2O3-based multilayer ceramic: a): Open microstrip.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 56
MCM-C, continued
Fig. 8.21.b: Characteristic impedance for typical geometries and
dimensions, Al2O3-based multilayer ceramic: b): Buried microstrip.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 57
MCM-C, continued
Fig. 8.21.c: Characteristic impedance for typical geometries and
dimensions, Al2O3-based multilayer ceramic: c): Stripline.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 58
MCM-C, continued
Table 8.6:
Properties of
alumina-based high
temperature
multilayer ceramic.
Ceramic
Property
Al203 content
Unit
%
Colour
Black
White
90
92
Density
g/cm3
3,60
3,60
Rel. dielectric const. (1 MHz)
Loss tangent (1 MHz)
Breakdown field
Resistivity
%
kV/mm
ohm cm
9,5
1,3
10
1014
9,0
0,3
10
1014
Thermal coeff. of expansion (0-100°C)
Thermal coeff. of expansion (0-300°C)
Thermal conductivity
Specific heat
Module of elasticity
ppm/°C
ppm/°C
W/m x °C
W s/g x °C
N/mm2
5,0
6,5
15
80
5,0
6,5
17
84
3x105
3x105
Conductors
Property
Tungsten
Sheet resistivity (0.1 mm con. width)
(0.2 mm - " - )
(0.3 mm - " - )
Thermal coefficient of resistance
Plated (W + Ni + Au)
Sheet resistivity
Unit
Value
ppm/°C
20
14
12
4300
mohm/sq
3-4
mohm/sq
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 59
Low Temperature Multilayer
Ceramic Modules - LTMCM-C
• Substrate materials
–Glasses, glass ceramics:
• Mullite, corderite, lead borosilicate glass...
–Conductors
• Gold, silver, AgPd
–Resistors
• Similar to thick film
• Properties: Table 8.7.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 60
LTMCM-C, continued
Inner Layer (Co-fired)
Gold
Silver
Silver/Platinum
Top Layer (Post fired)
Gold
Platinum/Gold
Silver/Palladium
Silver
Resistance [mohm/sq]
Fired Thickness [µm]
5
5
20
7
8
8
4
80
20
4
8
15
15
15
Table 8.7: Electrical and physical properties of low temperature
multilayer ceramic. a): Electrical properties.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 61
LTMCM-C, continued
100 ohm/sq
10 Kohm/sq
100 Kohm/sq
Over Tape
R [ohm/sq]
HCTR [ppm/°C]
122
+20
10,0 k
+71
92,4 k
+75
Over Thick Film Dielectric
R [ohm/sq] HCTR [ppm/°C]
102
+65
12,5 k
+41
95,7 k
+73
Table 8.7: Electrical and physical properties of low temperature
multilayer ceramic. b): Resistor Performance - Resistance and
TCR.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 62
LTMCM-C, continued
Table 8.7:
Electrical and
physical
properties of
low
temperature
multilayer
ceramic.
c) Physical
properties.
Thermal expansion
Fired dielectrics
96% alumina
Fired density
Theoretical
Actual
Camber
Fired
68 x 68 mm2 (2.7 x 2.7 in2)
Surface smoothness
Fired dielectric
50 x 50 mm2 (2 x 2 in2)
Thermal conductivity
Fired dielectric
Flexure strength
Fired dielectric
96% Alumina
Flexure modulus
Fired dielectric
96% Alumina
7,9 ppm/°C
7,0 ppm/°C
3,02 g/cm3
>2.89 g/cm3 (>96%)
±75 µm (±3 mil.)
0,8 µm/50mm
(Peak to peak)
15 - 25% of alumina
2,1x103 kg/cm2 (3,0x104 psi)
3,8x103 kg/cm2 (5,6x104 psi)
1,8x106 kg/cm2 (2,5x107 psi)
0,9x106 kg/cm2 (1,3x107 psi)
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 63
LTMCM-C, continued
• Advantages
–Low process temperature
–Most process steps can be done in high
temperature thick film production line
–Flexibility in conductor materials, low sheet
resistivity
–Plating not necessary for bonding
–Screen printed resistors
–Low r dielectric materials
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 64
LTMCM-C, continued
• Disadvantages
–High costs
–Low thermal conductivity
–Brittle materials
–Low availability
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 65
Power Electronic Modules
• Challenges
–Spread the heat, reduce thermal resistance
–Reduce thermal stress
–Provide electrical insulation for ~ 2.5 kV
–Design for EMC, reduce L
–Higher integration "smart power”
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 66
Power Electronic Modules,
continued
• Technologies
–Polymer on metal
–Thick film
–Plated ceramic substrate
–Direct Copper Bonding (DCB)
–Plasma sprayed dielectric on metal base
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 67
Power Electronic Modules:
Direct Copper Bonding
Fig. 8.22 a): The coefficient of thermal expansion for direct copper bonding
(DCB) substrates with a layer of 0,6 mm alumina sandwiched between Cu layers
of various thicknesses as given in the figure.
b): The number of thermal cycles to fracture for DCB substrates with varies Cu
thickness. The cycles were in the temperature interval -40 - +110°C.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 68
Direct Copper Bonding,
continued
Fig. 8.23: Power electronic module
[Toshiba data sheet]. The substrate
(top) is DCB with AlN insulation.
It is soldered to a heavy Cu plate,
environmentally protected with
silicone gel and mounted in a
plastic package with heavy screw
terminals. Each of the transistor
chips and diode chips conducts up
to 50 A current.
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 69
Combination Technologies
•Multilayer thin film - on multilayer ceramic
a)
Fig. 8.24: High performance
modules made in a combination
of multilayer thin film and multi
layer ceramic technology:
a): NEC Corporation computer
SX-3 using flop TAB carrier on
thin film and alumina based
substrate.
b): IBM Enterprise System/9000
packaging hierarchy using flip
chip, polyimide/copper thin film
on 63 layers glass ceramic
substrate.
b)
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Slide 70
Combination Technologies, continued
• Thin film - on - thick film (ame, Horten).
Fig.8.25:
1. Alumina substrate.
2.a,b,c,d: Printed conductor on first layer.
3. Printed dielectric film.
4. Optional compensation printed in vias.
5.a,b,c: Printed conductor on second layer.
6. Glass based dielectric.
7. a,b,c,d: Tantalum nitride resistive layer.
Electronic Pack…..
8.a,b,c,d: Molybdenum diffusion barrier.
9.a,b,c: Thin film gold lines.
10. Via hole between thin film and thick
film conductive layer.
11. Contact area in thick film. Goldplatinum or gold-palladium.
12.a,b: Resistor in thin film made by
selective etching in thin film structure
Chapter 8: Hybrid Technology and Multichip Modules
Slide 71
End of Chapter 8:
Hybrid Technology and Multichip Modules
•Important issues:
– Thick film technology:
• Understand the basic material considerations:
–
–
Substrate materials:
Thick film pastes
• Understand the basic manufacturing steps:
–
Process flow diagrams from printing to final test
•
Chip-and-wire or SMD component assembly
• Distinguish between High Temperature and Polymer Thick Film Technologies
– Thin Film Technology
• Understand the basic material considerations:
–
–
Substrates: Ceramic, glass or silicon
Thin film conductors, resistors and dielectrics
• Understand the basic manufacturing steps:
–
Process flow diagrams from deposition to final test
– Hybrid Multichip Modules
• MCM-D and MCM-C: Basic process steps
– Combination technologies
–
–
Applications with special requirements
Cost versus performance optimisation or compromise
•Questions and discussions?
Electronic Pack….. Chapter 8: Hybrid Technology and Multichip Modules
Slide 72