X-Ray Upgrade Can See Transistors in 3D
You can now make a map of even the most advanced chips without destroying them – IEEE
An upgraded X-ray imaging technique can provide crisp, 3D images of the inner workings of chips, revealing their designs and their flaws. The method has a resolution of 4 nanometers, providing images clear enough to map a chip’s wiring paths and reveal tiny transistor features without destroying the chip.
A team of scientists at Paul Scherrer Institute, including Tomas Aidukas and Mirko Holler, developed the improved imaging technique along with University of Southern California’s Tony Levi and ETH Zürich’s Gabriel Aeppli. It builds on an earlier method developed by largely the same team, called ptychographic X-ray laminography (PyXL). Levi says they wanted to provide an alternative to the time consuming, destructive processes used to perform quality control and reveal chip designs.
Using the state of the art chip imaging techniques, “you really need to know what you’re looking for ahead of time,” says Baohua Niu, a principle engineer at the Intel Foundry, in Hillsboro, Ore., who was not involved with the research. Today’s chips are so complicated that electrical tests alone can’t pinpoint where a defect is, he says. Engineers use a mix of optical imaging and other methods to zero in on potential problem areas. They then image that part of a chip’s surface with scanning electron microscopy, and finally take a slice of a chip for further imaging with a transmission electron microscope (TEM). When they find the flaw, they can then go back and correct their design.
The new imaging technique uses “hard” or high energy X-rays produced at a particle accelerator called a synchrotron. These beams can penetrate all the way through a chip, no slicing required. “Unlike with an optical microscope, it’s very difficult to make lenses,” Levi says of the X-ray range. His group’s method works by repeatedly illuminating the sample from different angles with a coherent beam of high energy X-rays. Tiny features in the chip diffract the light. Algorithms then reconstruct the most likely version of the image based on the intensity and phase of the diffracted X-rays. This kind of imaging is generally called ptychography.
If you enjoyed this article, you will like the following ones: don't miss them by subscribing to :
