Die Bonding

Die bonding is the process of attaching a semiconductor die to substrate/package, providing mechanical robustness, and electrical connectivity and allowing the removal of heat from the device.

Selection of the optimal die attach material and process is based on a number of issues, including thermal requirements, electrical requirements and mechanical stability. 

• Epoxy dispense, Daubing or Jetting
• Ag pressure-less sintering paste
• Solder and Eutectic die bonding.
• Placement tolerance down to +/-50um.

Epoxy die attach is a common approach to bonding since it offers the lowest cost and throughput.  Epoxies used are generally electrically conductive, or electrically non-conductive.  Both material types offer good thermal conduction to remove heat from the chip into the package substrate which can then be further removed through the PCB or specific heat sink. 

Alter Technology offer epoxy die attach using a needle dispense process, suitable for large die, and an epoxy daubing or stamping process which can create small controlled dots of epoxy for attaching die down to 200x200um such as LEDs and VCSELs.  

Epoxies are usually thermally cured during an off-line batch curing process, performing the curing on a batch basis reduces throughput time associated with individual reflow required for solder or eutectic processes. 

Pressure-less silver sintering pastes are used to offer similar electrical and thermal conductive to solders, but they can be applied and cured in a similar way to epoxy.  Alter have used Ag sintering pastes for applications requiring high heat dissipation such as high-brightness LEDs, laser diodes and RF MMIC dies.