"Fifty years ago today, 33-year-old GE scientist Dr. Nick Holonyak, Jr., invented the first practical visible-spectrum light-emitting diode (LED), a device that GE colleagues at the time called 'the magic one' because its light, unlike infrared lasers, was visible to the human eye. " This was the opening paragraph in GE Lighting's press realease, which hit the wires on October 10, 2012. The press release continued with "Holonyak has called the LED the 'ultimate lamp' because 'the current itself is the light.' As a result, an LED can have lower losses and higher efficiencies than other lighting technologies."
Within the past 50 years, LEDs have become more and more an inherent part of everyday lighting. However, the LED applications we see today require maximum thermal transfer to achieve increasingly higher performance requirements. Most of LEDs' efficiency is directly correlated with the design enhancements, which are best supported by automated eutectic solder die attach with a Pulsed Heat System.
Automated Production
Automated bonding systems have played a revolutionary role in the development of the robustness of light emitting diodes. Automated die attach (die bonding) systems equiped with a Pulsed Heat System enable heat ramp and cool down required by precision eutectic attach processes.
What is the Pulsed Heat System?
Simply explained, a Pulsed Heat System provides a heated platform for eutectic solder bonding. The stage "pulses heats", 
which means it raises and lowers the temperature of heated area following a programmable, user-defined eutectic heat profile.
In the graph to the right, you can see heating "overshoot", an error in temperature profiling that may degrade the quality of eutectic soldering. When performing HB LED attach, this error is very likely to damage the device. A tightly control temperature profile is imperative to high-reliability LED eutectic attach.
Eutectic Soldering with Pulsed Heat System
The graph to the right was captured with eutectic LED die attach using a Pulsed Heat System. As evident, the graph shows excellent consistent eutectic attach temperature control.
Value of Automation for Ultra High-Precision Applications
With the ever-evolving trend for smaller LED applications, the capability to produce high-precision, high-reliability bonding remains imperative. In a recent interview with Yole Developpement, Palomar Technologies' Donald Beck declared, "we have seen some LED light engine designs requiring sub-3μm placement requirements. These tend to be designs with focus lenses so that alignment of the LEDs to the lens is critical." In this interview, Don provided insight on topics including:
- Equipment lifecycles
- Added value with high-accuracy systems
- How to integrate progressive application roadmaps
- Future of chip-to-chip versus chip-to-wafer
- LED markets requiring high-accuracy packaging
Click here to download the "Value of Automation" interview transcript.
The Palomar Technologies team echos the sentiment provided by Mary Beth Gotti, manager of the GE Lighting Institute: "Nick Holonyak is a national treasure. His curiosity and drive to explore and invent have inspired thousands of students and countless innovations. It's breathtaking to consider the widespread and profound impact of 'the magic one' that Nick Holonyak brought to life 50 years ago."
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Jessica Sylvester
Marketing Communications
Palomar Technologies, Inc.