Line up for this ruler
2004 R&D 100 Winner
While it may sound like a measuring device for Lilliputians, the Nanoruler is actually a tool used for patterning large gratings with very high accuracy. Created by a team led by Mark Schattenburg at Massachusetts Institute of Technology, Cambridge, the device uses scanning-beam interference lithography (SBIL) to pattern gratings with distortions that are 10 to 100 times smaller than previously available.
Traditional mechanical ruling is extremely slow, taking many weeks to rule certain gratings. Electron beam and leaser beam lithography techniques produce gratings with a great deal of high spatial-frequency errors due to beam deflection jitter. The Nanoruler avoids these problems by sanning a high-fidelity grating image over the substance. The SBIL technique keeps the beams small so that a precise, high-quality grating image is obtained. Then the substrate is scanned under the fixed image using a high-performance air-bearing stage. By overlapping scans, even the small distortions of the fringes in the grating image are smoothed out, resulting in a large rating with extremely small distortions. Once applied, the system is capable of patterning gratings down to 200 nm on 300-mm dia substrates in 20 min—10 to 1,000 times faster than previous techniques.
Applications include use as optical encoders, length scale standards for the semiconductor industry, deep-UV excimer laser, and high-density magnetic storage.
Tool used for patterning large gratings