ALPHA® Argomax® Ag Sinter Technology for LED Automotive Applications
Posted 2/5/2014 by Ravi M. Bhatkal, Ph.D.
ALPHA® Argomax® Ag sintering materials can be processed at 190°C to 300°C under pressure, to form a pure Ag interface. After bonding, an Argomax® joint has a melting point of 962°C, the same as bulk silver. The material and process yields joints with thermal conductivities in the 200-250W/mK range, with thin, uniform bond lines. The resulting bond is a pure diffusion bond with no intermetallics.
Argomax® Ag sintering technology, offered in a film form factor, can provide automotive LED assemblies with:
- No die tilt, highly controlled and uniform bond line, which provides excellent control of directionality and optical axis.
- No bleed-out of the die attach material, ensuring die-footprint-conformal die attach yielding smaller package and module sizes.
- Placement of an array of die closer together without movement or “die float” which yields higher lumen density in a smaller area.
- Ultra-high thermal conductivity, enabling thermal resistance reduction, and therefore, lower junction temperatures, or higher drive currents. This can yield brightness improvement and control of wavelength shift and the ability to handle very high power densities.
- Very high die shear strength and thermal cycling/thermal shock reliability as shown in Figure1.
Figure 1: ALPHA® Argomax® Provides High Thermal Cycle and Thermal Shock Reliability.
The process is high volume manufacturing (HVM) capable, with sintering process UPH capability in excess of 20,000 die bonded packages per hour. This is shown in Figure 2.
Figure 2: ALPHA® Argomax® Processing Options and HVM Capability.
Summary and Conclusions
High reliability, high thermal technologies such as ALPHA® Argomax® Ag sintering film can be used to provide high reliability, high thermal joints for LED assembly in high power automotive lighting applications.