Images of a microelectronic device with the X1-SPEM, a first generation scanning photoemission microscope at the National Synchrotron Light Source

Abstract

We have recently completed the first generation scanning photoemission microscope at beamline X1A at the National Synchrotron Light Source (NSLS), the XLSPEM. The instrument is designed to use the soft x-ray unduiator at the NSLS as a high brightness source to illuminate a Fresnel zone plate, thus forming a finely focused probe, <0.4 //m in size, on the specimen surface. A grating monochromator selects the photon energy in the 400-80(3 eV range with an energy resolution of 0.8-2 eV. The flux in the zone plate focus is in the 108–109 photons/s range. A single pass cylindrical mirror analyzer (CMA) is used to record photoemission spectra, or to form an image within a fixed electron energy bandwidth as the specimen is mechanically scanned. The best one-dimensional resolution achieved so far is 0.1 fixn, as judged by the 25%-75% intensity rise across an edge. This is close to the diffraction limit of the zone plate used. Due to astigmatism introduced by the beamline optics, the two-dimensional resolution in the plane of least confusion is presently limited to 0.4 //m. Images of a microelectronic device are presented, along with some representative spectra, to demonstrate the present capabilities. With an upgrade of the beamline optics, and a new generation of zone plates, the two-dimensional spatial resolution in a second generation instrument is anticipated to be about 50 nm. © 1991, American Vacuum Society. All rights reserved.