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Geo-Spatial Outlier Detection


Comparing die test results with other die on a wafer helps identify outliers, but combining that data with the exact location of an outlier offers a much deeper understanding of what can go wrong and why. The main idea in outlier detection is to find something in or on a die that is different from all the other dies on a wafer. Doing this in the context of a die’s neighbor has become easie... » read more

Cleaning Up During IC Test


Test is a dirty business. It can contaminate a unit or wafer, or the test hardware, which in turn can cause problems in the field. While this has not gone unnoticed, particularly as costs rise due to increasing pin and ball density, and as more chips are bundled together in a package, the cost of dirt continues to be a focus. Cleaning recipes for test interface boards are changing, and analy... » read more

IC Data Hot Potato: Who Owns And Manages It?


Modern inspection, metrology, and test equipment produces a flood of data during the manufacturing and testing of semiconductors. Now the question is what to do with all of that data. Image resolutions in inspection and metrology have been improving for some time to deal with increased density and smaller features, creating a downstream effect that has largely gone unmanaged. Higher resoluti... » read more

Reliability Costs Becoming Harder To Track


Ensuring reliability in chips is becoming more complex and significantly more expensive, shifting left into the design cycle and right into the field. But those costs also are becoming more difficult to define and track, varying greatly from one design to the next based upon process node, package technology, market segment, and which fab or OSAT is used. As the number of options increases fo... » read more

Is There a Practical Test For Rowhammer Vulnerability?


Rowhammer is proving to be a difficult DRAM issue to fix. While efforts continue to mitigate or eliminate the effect, no solid solution has yet made it to volume production. In addition, more aggressive process nodes are expected to exacerbate the problem. In the absence of a fix, then, testing may be one way to give DRAM manufacturers and users some way to segregate devices that are more su... » read more

Digging Much Deeper With Unit Retest


Keeping test costs flat in the face of product complexity continues to challenge both product and test engineers. Increased data collection at package-level test and the ability to respond to it in a never-before level of detail has prompted device makers and assembly and test houses to tighten up their retest processes. Test metrology, socket contamination, and mechanical alignment have alw... » read more

Managing Wafer Retest


Every wafer test touch-down requires a balance between a good electrical contact and preventing damage to the wafer and probe card. Done wrong, it can ruin a wafer and the customized probe card and result in poor yield, as well as failures in the field. Achieving this balance requires good wafer probing process procedures as well as monitoring of the resulting process parameters, much of it ... » read more

Chip Monitoring And Test Collaborate


As on-chip monitoring becomes more prevalent in complex advanced-node ICs, it’s easy to question whether or not it conflicts with conventional silicon testing. It might even supplant such testing in the future. Or alternatively, they could interact, with each supporting the other. “On-chip monitors provide fine-grained observability into effects and issues that are otherwise difficult or... » read more

Testing Analog Circuits Becoming More Difficult


Foundries and packaging houses are wrestling how to control heat in the testing phase, particularly as devices continue to shrink and as thermally sensitive analog circuits are added into SoCs and advanced packages to support everything from RF to AI. The overriding problem is that heat can damage chips or devices under test. That's certainly true for digital chips developed at advanced node... » read more

Chasing Test Escapes In IC Manufacturing


The number of bad chips that slip through testing and end up in the field can be significantly reduced before those devices ever leave the fab, but the cost of developing the necessary tests and analyzing the data has sharply limited adoption. Determining an acceptable test escape metric for an IC is essential to improving the yield-to-quality ratio in chip manufacturing, but what exactly is... » read more

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