A novel micro-structured reference material for microbeam analysis

In order to determine the beam spot size and the linear or raster scanning properties of microprobe analytical systems, a novel certified reference ma terial (CRM) has been developed by IRMM, consisting of permalloy (81% Ni, 1 9% Fe) strip patterns of different widths on a silicon substrate. The gener al layout of this micro-structured reference material with pattern sizes ra nging from 2 to 100 mu m, fabricated with production schemes of microelectr onics circuitry on silicon wafers, is discussed. The large size range of th e individual pattern structures makes the material equally applicable to ve ry fine and less focused microbeams. Several long distances between charact eristic patterns as well as broad line widths of selected structures are ce rtified for each individual chip. First chips of this material were investi gated with high-energy ion microprobes as well as with X-ray microprobes wi th capillary optics. Due to the very good definition of the metal lines and their edge profiles, line scan results of XRF, PIXE or RES can be directly converted to spot size and microbeam profile. A special set of micro-struc tures on the CRM chips allows to obtain quantitative information about the "skirt" of microbeams. (C) 2000 Elsevier Science B.V. All rights reserved.