Impractical Stencil Aperture Designs to Enable M0201 Assembly
Effectiveness of I/O Stencil Aperture Modifications on BTC Void Reduction
Microalloyed Sn-Cu Pb-Free Solder for High Temp
Selective Reflow Rework Process
Impact of Thermal Loading on the Structural Intergrity of 3D TSV Package
Design and Fabrication of Ultra-Thin Flexible Substrate
Influence of PCB Surface Features on BGA Assembly Yield
Last Will and Testament of the BGA Void
Latest Industry News
Print These Electronic Circuits Directly Onto Skin
Compal increasingly asked to diversify production bases
Intel's margins tumble as customers shift to cheaper chips, shares slide 10%
From Foldable Phones to Stretchy Screens
6 Considerations for Integrating Sensors in Vehicles
Bill Gates Says Unhappy Customers Are Good for Your Business. Here's Why.
iPhone 12 review: Upgrade for the camera, not 5G
Apple's shifting supply chain creates boomtowns in rural Vietnam

High Thermal, High Temperature Interconnects for Ultra High Power LEDs

High Thermal, High Temperature Interconnects for Ultra High Power LEDs
For high performance applications, ultra-high power offers cost reduction through fewer LEDs, smaller PCBs, smaller heat sinks and lighter load bearing.
Production Floor


Authored By:

Ravi M. Bhatkal, Ph.D. and Ranjit Pandher, Ph.D.
Alpha Assembly Solutions
South Plainfield, NJ, USA


Use of super/ultra-high power LEDs is increasing. For high performance applications such as street lighting and ultrahigh power density illumination, use of ultra-high power can enable significant systems cost reduction through use of fewer LEDs, smaller PCBs, smaller heat sinks and lighter load bearing structures. In order to be able to drive the LEDs harder and to increase light output in a smaller footprint, one needs efficient thermal performance at the LED die-to-package connection. The ultra-high power density, combined with high thermal metal substrates, (which have high CTE mismatch with ceramic sub-mount LEDs) necessitates use of ultra-high reliability interconnects for elevated temperature operation at the package-to-board connection.

This paper presents two technology platforms: 1. Sintered silver, which enables significant increase in light output at package level, and 2. High temperature creep resistant solder alloys that provide high thermal cycling reliability under high temperature and high CTE mismatch conditions.


1. For high and ultra-high power LEDs, for a given LED package structure and board material used, it is beneficial to use solder joints with improved mechanical and thermal fatigue/creep and vibration resistance. A new class of creep-resistant and vibration resistant alloys has been developed, that can provide this capability, via a micro-structural control approach. These advanced alloys have been developed with special additives for improved thermal stability for high temperature operation and higher thermal fatigue and vibration resistance.

2. Sintered silver technology has several benefits for high and ultra-high power LEDs, including enabling higher light output while maintaining junction temperature, enabling excellent control of tilt, directionality and optical axis, and providing very high thermal cycling reliability.

3. These emerging technologies are enabling us to push the envelope in implemeting ultra-high power LEDs in several applications.

Initially Published in the SMTA Proceedings


No comments have been submitted to date.

Submit A Comment

Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name

Your Company
Your E-mail

Your Country
Your Comments

Board Talk
Causes of Blowholes
Tips When Moving a Reflow Oven
Assembling Boards with BGAs on Both Sides
Larger Stencil Apertures and Type 4 Paste
5 vs 8-Zone Ovens
Component Moisture Question?
BGA Components and Coplanarity
How To Verify Cleanliness After Rework and Prior to Re-coating?
Ask the Experts
Initial Screen Print Test Board
HASL Surface Finish and Coplanarity
Legend Marking Discoloration
Cleanliness Testing
Stencil Cleaning Frequency
Exposed Copper Risk
Spotting After DI Water Cleaning
ESD Grounding - 1 Meg Ohm Resistor