Chip Packaging -an Overview

The various types of IC Packaging are

• Flip Chip
• Multichip Module (MCM)
• Chip Scale Package (CSP)
• Quad Flat Packs (QFP)
• Stacked Die Packages
• Ball Grid Array Packages (BGA)
• Land Grid Array (LGA)
• SiP
• Quad No-lead Packages (QFN)
• Plastic Leaded Chip Carriers (PLCC)
• SO
• SOT
• TSOP
• WLP

The metric to select the packaging are

• Cost
• Reliability
• Form factor (Packing Density)
• Performance {Simultaneous Switching Noise, Signal Propagation, Power ground distribution}
• Thermal and Electrical Enhanced

In this article let us compare wire bond and flip chip package

Wire bond

-Diagram courtesy National

• Flexibile
• Cost effective
• Suitable for limited number of pads
• Mass production of wire-bonding pitch is in the range of 60 micron.

Challenges involved in Wirebonding

• Reduction in Wire Diameter
• Wire length Increase
• Loop height minimum achievable
• Wire Bond pitch reduction
• Pad Size Opening reduction
• BGA Package total height reduction

Measures for Good Quality Wire-Bonding

• Plasma clean prior to wire bonding
• Avoiding damaging to  Pad Metallization
• Using Wire Pull testing
• Meeting minimum bond strength limit
• Performing burn-in wire pull

Wire Bond Reliability Test

• Performing Temperature cycle testing (TCT) for 1000 cycles from -65 to 150 degree C
• Wire pull test data exposed to 1000 hours at 150 degree C
• Intermettallic Mass(Halo) @ Ball edge

-Diagram Courtesy Atmel

Flip chip

• Good Power and Ground Distribution possible
• With the Area array more I/O density is possible
• Low stress over active area
• Targetted for High device speed
• Low inducatance effects
• Costlier
• Production area array pitch around 178 micron.

Process Flow's

Future Technologies

• WLP
• WLBI (Wafer Level Burn in)
• Optical Interconnects
• Multiple Die-Stacking

Companies Involved in IC Packaging

• AmKor
• Signetics
• STATS ChipPAC
• ChipMOS
• Hana
• I2A
• Lingsen
• Infiniti
• OSE
• Shinko Electric
• SPEL
• UTAC
• Walton
• Carsem
• FlipChip  International
• Fujitsu
• Greatek Electronics
• Millennium Micro
• NS Electronics