Intel measures nanometer structures of chips with X-ray diffraction

Intel and NIST have successfully deployed an X-ray diffraction technique to measure the tiny structures of chips. The research makes the technique a candidate for use as a measurement tool for increasingly smaller and more complex chip structures.

Current tools used to check structures on chips in manufacturing are approaching their limits due to process reduction and complexity, such as the move from flat transistors to finfet variants. Researchers from Intel and NIST have succeeded in using X-ray diffraction to measure nanometer structures the width of a single silicon atom.

The technique that the scientists use is the cdsaxs technology. According to NIST researcher R. Joseph Kline, compared to other measurement methods, this “mapped by far the smallest and most complicated nanostructures”. “The results show that cdsaxs have the resolution to meet the requirements of next-generation metrology,” said Kline.

Intel and NIST applied the X-ray diffraction method to samples with structures resembling shark fins. The fins were 12 nanometers wide and 32 nanometers high. The differences in height between the structures ranged less than 0.5 nanometers. Using cdsaxs, the researchers were able to accurately register deviations down to 0.1nm.

The technique, which NIST has been working on since 2000, captures patterns of the scattering of X-rays with a wavelength of 0.1nm. The scattering is caused by collisions with the electrons in the nanostructure. The wavelength of the radiation does not change, but the impulse does. Computers can calculate the original shape of the structure using the diffraction pattern. This technique has been used for some time to determine crystal structures in detail.

Intel and NIST show an example from the left of an X-ray interference pattern caused by the nanostructure. Top right the result of the analysis of the cdsaxs measurements, below that an image of comparable structures, made with an electron microscope.