editor's blog
Subscribe Now

What Makes LEDs Different?

Earlier this month, KLA-Tencor released their ICOS WI-2280 inspection tool for LEDs. Reading through all the things it does and the improvements in provides – things like enhanced recipe qualification and reduced setup time – well, for someone like me who doesn’t spend all his time in this world, you start to think… This sounds like a lot of other inspection tools. And there do seem to be a lot of different tools.

It makes you wonder, why can’t one tool simply do it all? Reading through what the 2280 does, it seems like it would be good stuff for any IC. So I asked that of them as one of those “OK, I feel really stupid asking this, but…” questions, and they clarified both why this is different from other IC inspection tools and what it is not intended to do.

First, and most fundamentally, LEDs use sapphire as a substrate, and it’s transparent. That means that different lighting is required as compared to a silicon wafer. I suppose you could argue that this should then just be a “setting” or adjustment on a more general-purpose tool. But that would fly up against a second concern: cost. The defects being detected on LEDs are in the 3-5-µm range, far larger than what you would look for on a 28-nm chip. No need to burden it with expensive micro-mote detection capabilities.

There’s also one other less obvious difference. LEDs are typically inspected again after dicing. It’s “relatively” easy to inspect dice on a wafer – once you align the wafer, you’re set. But with dice in trays, each die can shift around, so post-slicing inspection requires separate attention that’s not needed for standard ICs.

Meanwhile, the 2280 is intended for all in-line inspections of patterned wafers (or diced wafers). It’s not intended for sampling (which may use a slower, more detailed analysis) or for inspecting the blank substrate.

You can find out more in their release.

Leave a Reply

featured blogs
Jan 17, 2022
Today's interview features Dajana Danilovic, an application engineer based near Munich, Germany. In this video, Dajana shares about her pathway to becoming an engineer, as well as the importance of... [[ Click on the title to access the full blog on the Cadence Community sit...
Jan 13, 2022
See what's behind the boom in AI applications and explore the advanced AI chip design tools and strategies enabling AI SoCs for HPC, healthcare, and more. The post The Ins and Outs of AI Chip Design appeared first on From Silicon To Software....
Jan 12, 2022
In addition to sporting a powerful processor and supporting Bluetooth wireless communications, Seeed's XIAO BLE Sense also boasts a microphone and a 6DOF IMU....

featured video

Synopsys & Samtec: Successful 112G PAM-4 System Interoperability

Sponsored by Synopsys

This Supercomputing Conference demo shows a seamless interoperability between Synopsys' DesignWare 112G Ethernet PHY IP and Samtec's NovaRay IO and cable assembly. The demo shows excellent performance, BER at 1e-08 and total insertion loss of 37dB. Synopsys and Samtec are enabling the industry with a complete 112G PAM-4 system, which is essential for high-performance computing.

Click here for more information about DesignWare Ethernet IP Solutions

featured paper

Enhancing PSAP Audio Performance and Power Efficiency in Hearables with Anti-Noise

Sponsored by Analog Devices

PSAP enhances user's listening experiences with hearables in challenging environments. Long delay in the audio system creates distortion known as comb effect in PSAP. This paper investigates the root cause of the comb effect and explains how a new anti-noise device yields a superior system performance compared to conventional PSAP solutions.

Click here to read more

featured chalk talk

Why Measure C02 Indoor Air Quality?

Sponsored by Mouser Electronics and Sensirion

The amount of carbon dioxide in the air can be a key indicator in indoor air quality and improving our indoor air quality can have a slew of benefits including increased energy efficiency, increased cognitive performance, and also the reduction of the risk for viral infection. In this episode of Chalk Talk, Amelia Dalton chats with Bernd Zimmermann from Sensirion about the reasons for measuring carbon dioxide in our indoor spaces, what this kind of measurement looks like, and why Sensirion’s new SCD4 carbon dioxide sensors are breaking new ground in this arena. (edited)

Click here for more information about Sensirion SCD4x Miniaturized CO2 Sensors