Latch-up happens when a voltage spike on one of the device pins causes a device to have a high and continuous supply current. A high supply current can lead to temporary failure or permanent damage to the device.

Back in the 1980s and 1990s, latch-up was a tremendous concern for the semiconductor world. The original test procedure for latch-up “JEDEC-17 Latch-Up in CMOS Circuits” was published in 1988 and replaced in 2022 by JESD78F.01. These procedures enabled manufacturers to get a handle on the problem and get the situation under control.

Present Day

Moving to the present day, semiconductor companies have focused on lower-power designs and scaled-down feature sizes. Both directions resulted in new, smaller device features that had become more sensitive to latch-up. This fueled a more recent round of testing and development. Most semiconductor products still aim to be smaller and use less power, but latch-up is still a concern, so new designs need to be tested before they can be shipped.

Our company provides a type of low-voltage latch-up capability with certain configurations of our MultiTrace. We are actively working on new software to support Static I-Test and VDD over-voltage testing using the same hardware you already rely on for powered curve tracing.

Still a Necessity by OEMs

Latch-up testing and characterization are still necessary for most semiconductor purchases at OEM companies. Latch-up remains a requirement in reliability testing for device manufacturers that are on the road to zero defects, or when their application requires an incredibly low (less than 1%) failure rate.

RTI’s MultiTrace Curve Tracers Support Latch-Up

DataTrace extraction tool. Click on image to expand.

MultiTrace and MegaTrace have supported static latch-up testing for as long as they have existed. The high performance of the SMUs in current source mode allows MultiTrace to support latch-up and curve tracing with various features. MultiTrace supports I-Test, VDD overvoltage test with the purchase of the MTForms Latch-Up version. The software comes bundled with a latch-up report generator and activation of the Data Extraction features in DataTrace.

Screenshot of an LU report. Click on image to expand.

Latch-up testing checks for supply current increases after applying overvoltage pulses to specific device pins. RTI has detailed application notes you can request if you would like to learn more.

Do you already have latch-up on your MultiTrace? We’d love to hear your feedback!

Going Beyond Reliability; Valuable for FA Engineers

Intended for the reliability engineer, latch-up testing is also valuable to the failure analysis engineer. Sometimes it is useful to show on a new device that latch-up is possible in order to show that it caused a failed device by latch-up.

Diagram of LU parasitic transistors. Click on the image to expand. 

The LU failure signature often damages the device severely, making it difficult to see the initiation point. Triggering latch-up in an emission system allows us to identify the failure mode and the exact point where corrective action is needed.

LU graph on DataTrace. Click on image to expand.

On the MultiTrace, latch-up is data intensive, unlike some production-oriented test systems. MultiTrace records current, voltage, and pulse current from all device power sources before, during, and after the pulse. A 6-bus MultiTrace can easily configure 2,4 VDD tests and, with some customization, up to 6 supplies. The powered curve trace method boosts trust in precise data and logical conditions during test development. Latch-up and powered curve trace have a strong correlation, which enables detailed FA and enhances the credibility of the outcomes.

Are you interested in adding latch-up to your current MultiTrace? Do you want more information on our latch-up bundle? Contact us and one of our team members will reach out shortly.