New build-up technique with copper bump

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New build-up techniquewith copper bump
AGP Process
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AGP Build-up PCB
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AGP Build-up PCB Section Figure

• Multi-via Structures

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Cross sectional view of AGP
To use copper bump as a connection between layers
Photo. 141 build-up PWB using AGP
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Cross sectional view of AGP
Copper bump
L1 alnd
L2 land
Photo. 222 build-up PWB using AGP
Photo. 343 build-up PWB using AGP
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Concepts of developing AGP 1. Possible to reduce
land size 2. Possible to stack vias 3. Possible
to form bumps of different diameters in a
one-step batch process 4. Improvement of
reliability of electrical connection
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Benefits of AGP

• 1. Possible to reduce diameter of via
• AGP bump is formed by etching
• method.
• It is possible to form micro-bumps
• with a diameter 50micron.

2. Possible to stack vias easily AGP enables
very flat land surface without
via-filling. It is suitable process for
multi-layer build-up structure.
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Benefits of AGP
3. High reliability of connecting Land to
via joining is achieved by copper
plating. This enables high reliability
of electrical connection and high
land- pull strength.
4. Possible to form bumps of different
diameters By selecting the size of the
etching mask, the bump of a different
diameter can exist together. Larger
bump can be used for the part where high
heat conductivity or low electric
resistance are necessary.
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Benefits of AGP
5. Low surface roughness of outer copper
Outer layer is formed by panel-plating.
It has sufficient peel strength even if there is
no anchor effect. This smooth
side contributes to the high frequency
characteristic.
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Structure that AGP enables
1. Multi build-up structure with stacking via







High density PWBs can be achieved by AGP.
2. Flip chip pad with micro via connection
It is suitable for MCM.

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Structure that AGP enables
Via and line can be connected directly without
forming land. It will bring drastic higher wiring
density.
3. Land-less pattern
3D view
Upper view
4. Rigidly improvement by copper frame
Because the bump layer is formed by the
etching, It is possible to process it to various
shape. That enables frame as illustrated, it
brings rigidly Improvement. It is also as
possible to build the coaxial cable Structure
into.
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Structure that AGP enables
5. Heat management by forming thermal via
BGA/CSP
Forming chip size heat sink By AGP process
Plugged via by using Conductive paste
Improvement of heat dissipation effect
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Schematic illustration of AGP process



Core board



Copper plated on core board



Forming bumps by etching



Forming dielectric layer(Liquid epoxy)



Copper plating as outer layer
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AGP Process
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AGP Process
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AGP Process
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AGP Process
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AGP Process
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AGP Process
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Manufacturing Spec
Minimum land size of outer layer 100?m
Minimum size of top of via 50?m

Dielectric thickness of AGP layer 3060?m
Dielectric consists of epoxy resin Not including
glass-cross

Minimum size of bottom of via 75?m
Minimum land size of inner layer 150 ?m
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Result of durability tests
Tests Conditions Standards Results Judgments
Humidity bias test (Cyclic) IPC-SM-840C Class T Insulation resistance 1x108? or more Peel strength of conductive 600g/cm or more 6x1011? 1.0kg/cm OK OK
Humidity bias test (Steady state) 40?/90R.H./50V 240hrs 85 ?/85R.H./30V 100hrs Insulation resistance 1x108? or more Peel strength of conductive 600g/cm or more Insulation resistance 1x108? or more Peel strength of conductive 600g/cm or more 2x1011? 1.0kg/cm 2x1011? 1.0kg/cm OK OK OK OK
PCT 121 ?/2atm /100R.H./96h 130?/2.3atm /85R.H./5.5V/168h Insulation resistance 1x108? or more 3x1011? OK
Dielectric strength Applying 500V in 5sec and keeping 1min No dielectric breakdown 2x1012? OK
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Result of durability tests
Tests Conditions Standards Results Judgments
Thermal shock test (Vapor phase) -65?/30min 125 ?/30min 1000cycles Change in resistance 10 or less 0.5 OK
Thermal shock test (Hot oil) 260 ?/5sec 20 ?/15sec 300cycles Change in resistance 10 or less 2.0 OK
Solder bath test 260 ?/10sec 3times Change in resistance 10 or less 1.0 OK
High temperature storage 125 ?/100hrs Change in resistance 10 or less Insulation resistance 1x108? or more Peel strength of Conductive 600g/cm or more 0.5 1x1010? 1.0kg/cm OK OK OK