|
|
 |
Anisotropic Conductive
Adhesives
|
Anisotropic conductive adhesives (ACA) provide high-speed
interconnection for flip chip, fine pitch chip-on-film (COF),
and chip-on-glass (COG) LCD packaging, and various fine
pitch assemblies. They are often used as interconnect material
in mainstream applications such as flat panel displays,
LCD, smart card, camera modules, mobile phones, direct access
sensors, semiconductor packages and RFID tags.
United Adhesives makes Au-based ACAs, and Ag-based low cost
ACAs for these applications. They all have a rapid snap-cure
speed at elevated temperatures in seconds with a thermo-compression.
They forms a structural bonding to various substrates and
films with conductivity only in z-direction while remaining
insulation in the x,y plane.
|
|
|
|
Name
|
AE
6017
|
AE
6020
|
AE
6025
|
AE
6050
|
|
Features / Advantages
|
Ag-Cu conducting particles. Size ~6um.
Low cost. Snap cure in seconds.
|
Au-polymer conducting particles. Mono-size
3 um. Flexible for compression. Snap cure in seconds.
|
Au-Ni conducting particles. Size ~ 2.5um.
Snap cure in seconds.
|
Au-Ni conducting particles. Size ~ 5.0
um. Snap cure
in seconds.
|
|
Typical Applications
|
Interconnection for flip chip, fine
pitch chip-on-film (COF), and chip-on-glass (COG)
LCD packaging, and various fine pitch assemblies
|
Interconnection for flip chip, fine
pitch chip-on-film (COF), and chip-on-glass (COG)
LCD packaging, and various fine pitch assemblies
|
Interconnection for flip chip, fine
pitch chip-on-film (COF), and chip-on-glass (COG)
LCD packaging, and various fine pitch assemblies
|
Interconnection for flip chip, fine
pitch chip-on-film (COF), and chip-on-glass (COG)
LCD packaging, and various fine pitch assemblies
|
|
Appearance
|
Grayish Blue
|
Dark Brown
|
Dark Brown
|
Dark Brown
|
|
Part / Component
|
One Part
|
One Part
|
One Part
|
One Part
|
|
Rheology
|
Dispensable
|
Dispensable
|
Dispensable
|
Dispensable
|
|
Viscosity @25C (cps)
|
25,000
|
25,000
|
26,000
|
23,000
|
|
Thixtropic Index
|
3.0
|
2.5
|
2.5
|
2.3
|
|
Density (g/ml)
|
1.42
|
1.2
|
1.32
|
1.35
|
|
Work life (hr)
|
> 48 hrs
|
> 48 hrs
|
> 48 hrs
|
> 48 hrs
|
|
Cure Rate
|
180C 6 sec
150C 20 sec
|
180C 7 sec
150C 25 sec
|
180C 6 sec
150C 20 sec
|
180C 6 sec
150C 20 sec
|
|
Shelf Life (days)
|
> 6 month
@ < 4C
|
> 6 month
@ < 4C
|
> 6 month
@ < 4C
|
> 6 month
@ < 4C
|
|
Hardness
|
Shore D = 85
|
Shore D = 86
|
Shore D = 86
|
Shore D = 86
|
|
Contact Resistivity, Ohm/mm2
(z direction, 24°C)
|
< 0.1
|
< 0.1
|
< 0.1
|
< 0.1
|
|
Volume Resistivity, Ohm-cm
(x, y direction, 24°C)
|
> 10E+12
|
> 10E+12
|
> 10E+12
|
> 10E+12
|
|
Coefficient of Thermal
Expansion (ppm/°C)
|
< 130 (above Tg)
< 50 (below Tg)
|
< 170 (above Tg)
< 80 (below Tg)
|
< 160 (above Tg)
< 60 (below Tg)
|
< 160 (above Tg)
< 60 (below Tg)
|
|
Tg
|
125
|
n.a.
|
135
|
135
|
|
Adhesion
(Al/Al lap shear)
|
> 800 psi
|
> 400 psi
|
> 1500 psi
|
> 1500 psi
|
|
|
The Anisotropic Conductive Adhesives (ACA) made by United
Adhesives conduct only in z-axis due to careful control
of the distribution of the electrically conductive filler
(gold coated, or silver particles) in the adhesive matrix.
Conductivity is achieved through continuous contact of the
fillers with the bumps and bond pads of the opposing substrates
after heat and pressure being applied to compress the entrapped
conductive particles. The epoxy matrix with the remaining
particles between the raised areas of the substrates acts
as an insulator, preventing current flow in any other directions.
These adhesives can be applied with dispensing, stencil
or screen-printing. Cure can be complete at 180C under the
compression force in less than 7 seconds. The gold particles
have stable electrical contact resistance when subjected
to humidity and thermal cycling.
United Adhesives provides strong bonds to fine pitches with
very fast assembling process. Testing results show that
pitches of 80 microns (70 micron bumps with 10 micron separation)
showed no circuit short.
|
|
|
|
|
