Flip chip is a die attach method where the electrical connections between the chip and package/substrate are made directly by inverting the die face-down onto the substrate/package.
The bond pads of the die are physically, mechanically and electrically connected to the bond pads of the package/substrates by conductive bumps.
Flip chip offers the following advantages over other die attach processes.
- Larger number of electrical connections can be made in a specific area on the die and the substrate which increases the I/O and packaging layout flexibility.
- Flip chip assemblies generally lead to smaller package sizes as wire bonds are not needed.
- Flip chip produces connections with lower parasitic inductance and capacitance which leads to superior electrical performance.
- More suitable for high frequency components.
- Lower electromagnetic emissions as unlike wire bonds there are no loops in the connections.
Flip chip process is used for packaging a broad range of electronics which include Integrated circuits, infrared sensors, large area pixelated detector arrays, optical devices, MEMS and surface acoustic wave (SAW) devices.
It is compatible with a wide range of substrates such as laminate PCB, polyimide, glass, ceramic, silicon and plastic package lead-frames.
Flip chip process can be used for directly attaching dies to the PCB board which may or may not have surrounding components packaged using flip chip technology.
It is often referred to as flip chip on board. It can also be used for packaging multiple dies in a single package known as flip chip in packages.
The flip chip technology can be used for producing 3-D packages where multiple dies can be packaged together in a cascaded arrangement.
The advanced packaging facility has a range of equipment required to make use of the flip chip technology.
It contains a high precision Finetech FINEPLACER® lambda flip-chip bonding machine with placement accuracy to 0.5 µm. It has manual, semi-automatic and automatic wirebonders for the bumping process.
The facility contains robotic dispensing and jetting system for underfilling the flip chip assemblies.
It also has a range of curing equipment which can be used for thermal and UV curing encapsulants.