“yieldHUB helped us develop a robust high yielding product”

Customer story

Fabless semiconductor company EnSilica was founded in 2001 by a group of UK-based designers and has recently joined the global stage with a range of automotive and industrial design wins that have now gone into production. One in particular is a safety-critical component for a well-known car manufacturer.

The company that specializes in custom ASIC design and supply for OEMs and system houses is nothing short of a success story. Having recently become a public company, they have been using yieldHUB as its chosen yield management platform since 2019.

EnSilica product development manager Andrew Murdoch has 25 years' worth of experience in the industry and previously worked for Atmel and Semtech before joining EnSilica in 2018.

“We’ve been building up the business in terms of the supply of chips and in particular within the automotive segment. 

“Demand is high so it’s a challenge to try and make it as efficient as possible through the design, manufacturing flow, and assembly tests. 

“That’s a key focus now and yieldHUB helped us develop a robust high-yielding product,” Andrew said.

The product development manager said it’s important to do research before choosing a yield management company.

“When I first joined we knew that we needed an analysis software that would help with engineering in the New Product Introduction (NPI) stages and also support us efficiently once in production. I had worked with other providers previously and had evaluated what was in the market. 

“For a company of our size and what we’re trying to do with a small number of engineers, the software needed to be very efficient without needing a huge IT infrastructure on our side, and as part of evaluating a few different companies, yieldHUB came out on top. It had the functionality we wanted to see, and yieldHUB was very engaging in terms of working with customers to build in functions that they’d like to see in the software.”

He said yieldHUB helped analyze an early version of silicon when they noticed one parameter was changing across some of the supply voltages.

“It was an unexpected variation that we saw on a parameter and, it was causing us some problems trying to meet the specifications. By using the supply voltage as a condition in yieldHUB, we were able to analyze quite a large sample size during engineering runs at package test.

“Because [of yieldHUB’s] characterization feature we were able to use the power of the analysis tool to show variation at different voltages and temperatures all in one plot to work out if we could improve things. 

“The parameter spread was inherently fairly wide at all conditions but yieldHUB's correlation and traceability functions allowed us to see what was going on, ruling quite a few potential root causes out.”

The results led Ensilica to some detailed analysis of the chip and a small design change that was successful. 

“Although the spread was still there, the variation across supply voltage flattened as expected and gave us a large margin to the spec. 

“Rather than us having yield numbers that went up and down and were unpredictable, we were able to improve the yield by 4% and it’s now very stable.”

He said they are happy with their choice of yield management solution.

“In these times it really helps us because we know almost exactly how many parts we’re going to get from one wafer lot in the fab rather than not knowing because it’s difficult to plan and causes a much greater operational overhead to manage the supply chain. 

“It means we don’t have to worry about this variation anymore, it’s helpful for a small company like us with not so many engineers. It shows the power of a tool like this. If you use it in the right way then you can help yourself be far more efficient. 

“It improved our yield and created lots of good-looking plots. As we increase our production volumes on different products and do more wafer testing, I know yieldHUB also has the right features for us in the future including advanced outlier detection.”

yieldHUB also has features that can track shifts in parameters for every single die either during qualification, test stages, or across characterization conditions, which can help analysis.

Further, he said he felt like he could count on yieldHUB’s customer support.

“I would definitely recommend them to other companies. I know what is around and the kind of things that fabless companies tend to need so I think yieldHUB would be the best solution.

“They really helped us with a smooth transition from engineering to production mode by guiding us in developing the recipes needed to automatically import and consolidate the data logs from our test sub-cons.”

Andrew revealed what’s happening in the current climate for automotive, which has become a trending topic.

“We’re quite proud of the fact we’ve done this as a new supply company and managed to get through all the qualification stages we need to get into an automotive product. 

“It’s a challenge now for the car companies and module suppliers for the cars as they’re traditionally more used to dealing with mechanical items. They want to make their cars reliable, but with more electronic chips going into them it's a big challenge to make sure they work all the time and people don’t have to bring the car back. 

“That's why they want low failure rates and demand high test coverage to make sure they work for more than 10 years without failing.

“Cars are basically computers on wheels now and are going to communicate, analyze everything and provide entertainment. They are only going to get more electronic as time goes on so quality is the most important criteria.”  

He said yieldHUB has a serial number feature that can trace each part back to its original test data at wafer or final package test. 

“This really helps efficient support and analysis of customer returns.”

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