Nanopackaging: Nanotechnologies & Electronics Packaging Part D ECAs, Simulation, & Nanoelectronics Packaging James E. Morris Department p of Electrical & Computer p Engineering, g g, Portland State University, Portland, Oregon, USA
[email protected]
Nanotechnologies in ECAs
ECA/ICA/ACA/ACP/ACF/NCA !!!! ICAs
4/21/2009
Nanoparticles Sintering Surface treatments
ACAs, NCAs, & miscellaneous CNTs Microvias 2
1
Nanoparticles
Percolation limits of different ICA filler particles 4/21/2009
3
Ag nanoparticles added to Ag-ICA [Fan/Su/Qu/Wong ECTC’04] 4/21/2009
4
2
Ag nanoparticles added Fan/Su/Qu/Wong [ECTC 2004]
4/21/2009
80% Ag + nanoparticles: ti l no effect 70% Ag + nanoparticles: percolation threshold Ag more effective as flakes 5
ICA: Mach, Richter, & Pietrikova Proc. ISSE 2008 Paper D003 pp. 230-235 Addition of Ag nanoparticles Specimen
Nanoparticles Dimensions (nm)
Concentration % (wt.)
Processing
S1
(3 - 55)
10
S2
(3 - 55)
20
Ag flakes substituted with Nanoparticles
S3
(3 - 55)
30
S4
(80 – 100)
3.8
S5
(6 – 8)
3.8
S6
(80 – 100)
7.4
S7
(6 – 8)
7.4
S01
Bis-phenol epoxy resin; 75 wt% Ag flakes 6-8µm
4/21/2009
Nanoparticles added
I‐V Non‐linearity
6
3
Nanoparticle inclusion in epoxy: AgNO3
Micro‐particles
[Wong et al, ECTC’06]
(hardener)
Nano‐particles 4/21/2009
7
Nanoparticle Sintering [Wong et al, ECTC’06]
4/21/2009
8
4
Isotropic Conductive Adhesives (ICAs) 20nm-sized Ag particles annealed at different temperatures for 30 minutes: (a) room temperature (no annealing); (b) annealed at 100oC; (c) annealed at 150oC; (d) annealed at 200oC and (e)annealed at 250oC. Lu et al (Markers: (a) 3μm (b) 2μm (c) 2μm (d) 3μm (e) 3μm ) (a)
(b)
((d))
(c)
(e) Liu et al
4/21/2009
9
A
Das & Egitto
(a) A' A
(b) A' Use of blind vias increases wiring density.
ICA Microvia Fill (PWB)
75°C micro/nano Ag sintering
LMP
Cu
Ag 4/21/2009
10
5
Nano-particle sintering [Wong et al, ECTC ’04 & ’06]
Surfactants: 5% diacids
Without surfactant
↓ With surfactant ↓ 4/21/2009
11
Stearic acid can be removed/replaced by short-chain dicarboxylic acids, with strong affinity for Ag surface (e.g. malonic acid) Li/Moon/Li/Wong ECTC 2004] resistivity((Ohm-cm)
1.60E-03 1.40E-03 1.20E-03 1.00E-03 8.00E-04 8.00E 04 6.00E-04 4.00E-04 2.00E-04 0.00E+00 ICA
ICA w ith Acid M
ICA w ith Acid A
ICA w ith Acid T
t le ad
malonic oxalic
0.06
terephtha
0.04
epoxy
0.02 0
r
C urr en
adipic
0.08
ete
stearic
0.1
ltim vo
clean
0.12
To
contact resistance(ohm)
0.16 0.14
4/21/2009 1
10 contact force(gram )
100
Experimental resistances with short‐ chain acids
12
[Qu – APM’05]
6
Anisotropic Conductive Adhesive (ACA) Enhancement (Rongwei Zhang et al ECTC’08)
Resistance ~mΩ █ █ █ █ SAM‐1:
4/21/2009
“Molecular wires” Oxide reduction Lower resistance Higher max current
13
10-20 nm nano-Ag fillers for NCAs (AgNO3 added to polymer)
4/21/2009
[Li/Moon/Wong ECTC’06]
14
7
CNT-PP (petroleum pitch) composite (C mesophase) fill for fillers f conductive pastes [Bondar et al, ECTC’05] 4/21/2009
15
Ag nanowire ACF (Au seed, Co alignment) [Lin et al, ECTC’05]
4/21/2009
16
8
Addition of CNTs to NCAs: 0.03 wt% CNTs increases electrical and thermal conductivities c. 20%
DSC
Jiang, Min, Moon, & Wong, Proc. ECTC 2008 pp. 1385-1389 4/21/2009
17
Zhang, Jiang, Liu, & Inoue ICEPT/HDP 2008 E3-04 Effects of CNT & Ag powder addition Sample
AF2 epoxy % matrix
3-10µm % Ag flakes
0.5-1µm % Ag powder
Vol % CNT
Resistivity µΩ.cm
AgF201
60.762
38.238
1
0
45
AgF202
60.762
37.238
2
0
39
AgF203
60.762
36.238
3
0
40
AgF204
60.762
35.238
4
0
39
AgF205
60.762
34.238
5
0
48
AgF206
60.762
39.238
0
0
52
3F201
60.762
38.138
1
0.1
34
3F202
60.762
37.938
1
0.3
36
3F203
60.762
37.738
1
0.5
29
CNT dispersion in epoxy: (a) CNTs untreated
4/21/2009
(b) CNTs treated H2SO4/HNO3 16hrs 50oC
18
9
Interface effects on the conductivity of CNT composites [Yan et al, Nanotechnology 2007]
4/21/2009
19
Microsprings (Ma et al) Sputter deposition: Ti release layer
Ti Release layer Sputter deposition: Mo80-Cr20 (Stress-engineering) Mo80-Cr20 metal
Pattern interconnect by photolithography
Define release window
Substrate
Photoresist
Etch release layer
Interconnect curls up automatically
4/21/2009
20
10
Nanosprings (Ma et al)
(a) Bare wafer
(b) Release layer deposition Single Layer
Bi-Layer
(c) Spin resist layer(s)
100 90 80 70 60 50 40 30 20 10
800 700 600 500 400 300 200
Width (nm)
((f)) Ultra-sonic removal of resist leavingg patterned p metal
900
(e) Metal deposition with intrinsic stress gradient
1000
(a)
(d) Pattern resist
(g) Spin resist and pattern for release
(h) Selectively etch release layer; intrinsic stress gradient causes cantilever to curl up
4/21/2009
21
Molecular Dynamics (* van der Sluis et al) Tinitial
Loading Conditions + repulsive potential ∝ 1 / r m
potential energy
Initial Conditions
total potential
r
Particles r0 attractive energy ∝ 1 / r n
-
Boundary Conditions 4/21/2009
Potential functions 22
11
Molecular Dynamics (* Fan & Yuen) Modeling of interface H2O diffusion, CNTs, etc
Adhesion increases with Cu2O growth, decreases with void development
EMC →
Cu2O → 23
MD simulation snapshots of the Cu2O/EMC system, showing void development at the interface
Nanoscale Modeling
(van der Sluis et al)
Molecular Dynamics; interscale interfaces Time WLCSP
Years dsDNA
Hours
Finite Element Method (Static)
Minutes SiOC:H
Seconds
Mesoscale Modeling (Segments)
Microseconds Atom
Molecular Dynamics (Atoms)
Nanoseconds Picoseconds Femtoseconds
Quantum Mechanics (Electrons)
e.g. Drug delivary Cell
e.g. Crystallisation, Transistor
e.g. Catalyst, electronics
Distance 4/21/2009
1Å
1nm
1μm
1mm
meters
24
Need software “interface” packages to transport modeling results between length scales
12
Nanoelectronics Packaging
nm CMOS Single electron transistor (SET) Discussion: CNTs, molecular, RTDs, spintronics, etc Sensors
4/21/2009
25
Nano-CMOS Packaging (Mallik)
4/21/2009
26
13
Nano-CMOS Packaging (Mallik)
4/21/2009
27
Nano-CMOS Packaging (Mallik)
M1 M2
Via’s
M3
Low K ILD M4
Interconnects Etch stop
M5
Low k ILD Porous dielectrics Brittle material Stress increasing problem Compliant interconnect
CNTs on solder bumps
4/21/2009
28
14
Single electron transistor (SET) as example Metal nanodot as simple SET example (a) Gate Capactor
Quantum dot (Island)
Source
Drain
Tunneling Junctions
(b)
d
Rd , Cd Qd
Vd C g , Qg
V ds
Island Qnet
g Vg
Vgs
Rs , Cs Qs
Vs
Radehaus et al s
4/21/2009
29
Coulomb block & SET: Electric field & temperature
T=0°K: abrupt threshold at V=δE/q 4/21/2009
T>0°K: randomly charged exp‐δE/kT
30
15
Nanoparticle Charging: the Coulomb Block (Morris) Spherical nanoparticles, radius r, separation s Electrostatic charging energy:
ΔE =
q2 q2 ⎡ 1 1 ⎤ → − 4πεr 4πε ⎢⎣ r r + s ⎥⎦ r 0
Electrostatic charging energy
↓
Field assistance
r+s
x
E(x) -q q Fx
Net thermal barrier →0 for qV=∆E 0.5nm
1nm
4/21/2009
2nm
4nm
31
Electrostatic activation/charging energy (usually stated δE=q2/4πεr)
δE = (q 2 / 4π ε )(r −1 − (r + s ) −1 ) − (2r + s ) q F
when F < (q / 4π ε )(r + s ) −2 and at high fields 1
δE = (q 2 / 4π ε )r −1 + (r / s)(2r + s)q F − (q 2 / 4π ε s) 2 ((2r + s)q F )
until 4/21/2009
δ E →0
when
q V = (1 + s / r ) δ EV =0
1
2
32
16
The geometry of 2 ellipsoidal nanodots of eccentricity e = (1-(t/r)2)½
4/21/2009
33
δE for oblate spheroids with applied field δE = q2/C = (q2/4πεR)(2/e)[sin-1e-sin-1(e(1-p)/(1+p))]/(1-p)-qREa for Ea
