Robert L. Gerlach FEI Corp. (United States) Michael R. Scheinfein Arizona State Univ. (United States) Geoffrey A. Crow Intel Corp. (United States) Mark Utlaut Univ. of Portland (United States) Charles Bickford FEI Corp. (United States)
Focused ion beam (FIB) systems are now commonly used in the semiconductor industry for failure analysis and circuit modification of various integrated circuits. Secondary Ion Mass Spectroscopy (SIMS) is coming into use as a means to detect endpoint in sputtering holes in the integrated surface as well as to perform thin film analysis. A key requirement of the SIMS optics is very high sensitivity as the primary Ga ion beam is typically in the 10 - 11 to 10 - 9 A current range. The input lens must efficiently extract low energy ions from the surface and transport them into the quadrupole mass spectrometer and match its input spatial, solid angle and energy characteristics. In addition, the input lens must fit between the sample and primary ion column. In this paper the theoretical solution is compared to experimental results.
Robert L. Gerlach,
Michael R. Scheinfein,
Geoffrey A. Crow,
"SIMS input lens", Proc. SPIE 2014, Charged-Particle Optics, (3 September 1993); doi: 10.1117/12.155695; https://doi.org/10.1117/12.155695