PCB And IC Technologies Meet In The Middle


Surface-mount technology (SMT) is evolving far beyond its roots as a way of assembling packaged chips onto printed circuit boards without through-holes. It is now moving inside packages that will themselves be mounted on PCBs. But SMT for advanced packages isn’t the same as the SMT we’ve been used to. “Many systems include multiple ASICs, a lot of memory, and that's all integrated i... » read more

New Memories Add New Faults


New non-volatile memories (NVM) bring new opportunities for changing how we use memory in systems-on-chip (SoCs), but they also add new challenges for making sure they will work as expected. These new memory types – primarily MRAM and ReRAM – rely on unique physical phenomena for storing data. That means that new test sequences and fault models may be needed before they can be released t... » read more

Fabs Drive Deeper Into Machine Learning


Advanced machine learning is beginning to make inroads into yield enhancement methodology as fabs and equipment makers seek to identify defectivity patterns in wafer images with greater accuracy and speed. Each month a wafer fabrication factory produces tens of millions of wafer-level images from inspection, metrology, and test. Engineers must analyze that data to improve yield and to reject... » read more

Making Test Transparent With Better Data


Data is critical for a variety of processes inside the fab. The challenge is getting enough consistent data from different equipment and then plugging it back into the design, manufacturing, and test flows to quickly improve the process and uncover hard-to-find defective die. Progress is being made. The inspection and test industry is on the cusp of having more dynamic ways to access the dat... » read more

Designing Chips For Test Data


Collecting data to determine the health of a chip throughout its lifecycle is becoming necessary as chips are used in more critical applications, but being able to access that data isn't always so simple. It requires moving signals through a complex, sometimes unpredictable, and often hostile environment, which is a daunting challenge under the best of conditions. There is a growing sense of... » read more

Why Wafer Bumps Are Suddenly So Important


Wafer bumps need to be uniform in height to facilitate subsequent manufacturing steps, but a push for 100% inspection in packaging in mission-critical markets is putting a strain on existing measurement technologies. Bump co-planarity is essentially a measure of flatness. Specifically, it measures the variation in bump height, which may have a target, for example, of about 100 microns. As a ... » read more

Who Owns In-Chip Monitoring Data?


In-chip monitors provide unprecedented visibility into the inner workings of complex integrated circuits for everything from process control to fine binning, preventive system maintenance, and failure analysis. But there may be many consumers of different slices of the data at very different phases of the chip lifecycle, raising questions about who controls and owns all of that data. The ans... » read more

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

5G Chips Add Test Challenges


The advent of chips supporting millimeter-wave (mmWave) 5G signals is creating a new set of design and testing challenges. Effects that could be ignored at lower frequencies are now important. Performing high-volume test of RF chips will require much more from automated test equipment (ATE) than is required for chips operating below 6 GHz. “MmWave design is a pretty old thing,” said Y... » 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

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