Here is the abstract you requested from the DPC_2009_LED technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Room Temperature Soldering of Temperature-Sensitive Surface Mount High Power LED Packages to Heat Sinks|
|Keywords: thermal management, device attachment, SMT|
|The lifetime of high-power LED devices is critically dependent upon the steady state die temperature and therefore the thermal management of the system. For packaged LED components the operating temperature of the die is strongly influenced by the heat sinking bond between the package and the underlying heat sink. For many thermally sensitive LED packages thermal adhesives are the only viable bonding solution option. In this presentation we detail a novel assembly process for these devices utilizing room temperature soldering to metallically bond the device directly to the substrate with minimal thermal exposure. The solder bond is achieved in less than a second, in air, at room temperature, with minimal thermal exposure to the components. Bonding is realized using a reactive multilayer foil material which acts as a localized heat source to solder the components together. Heat is generated by initiating a self-propagating, exothermic reaction in the foil via a small energy impulse. The thermal energy produced rapidly melts adjacent solder layers, bonding the components while limiting reflow temperatures to the interface. In previous papers we have detailed the use of reactive bonding (or NanoBond®) for CPU and GPU thermal interface applications. In this presentation we report new results on utilizing multilayer foils to solder-bond commercial high brightness packaged LEDs to metal core PCBs. We present data regarding the thermal and structural performance of the bonds both before and after reliability testing. We then compare, on actual bonded devices, the characteristics of the bonds to those of competing technologies such as high performance thermal epoxies and conventionally reflowed solder. We demonstrate that the bonds using the reactive multilayer foil exhibit thermal resistances on par with reflow and one sixth that of epoxies.|
|Ramzi Vincent, Engineer
Reactive NanoTechnologies Inc. (RNT)
Hunt Valley, MD