Hostname: page-component-77c89778f8-7drxs Total loading time: 0 Render date: 2024-07-16T23:54:49.303Z Has data issue: false hasContentIssue false
  • English
  • Français

Quantitative Microprobe Analysis of Thin Insulating Films

Published online by Cambridge University Press:  06 March 2019

J. W. Colby
J. W. Colby*
Affiliation:
Bell Telephone Laboratories, Incorporated Allentown, Pennsylvania
Get access

Abstract

The analysis of thin insulating films occurring in various stages of the manufacture of integrated circuits has in the past been difficult, if not impossible. Their dimensions usually preclude analysis by conventional chemical techniques, hence very little is known concerning their relative stoichiometrics. However, by microprobe analysis, films as thin as 540 Å (∼18μg/cm2) have been successfully analyzed. In general, two different approaches are taken, depending on the film thickness. Usually, films thicker than 2500 Å (∼50μg/cm2) are analyzed by conventional microprobe techniques. A computer program, called MAGIC, has been written, which converts the raw X-ray intensities to chemical composition. All data are corrected for dead time, background, absorption, atomic number effects, and fluorescence by characteristic radiation, if required. A minimum of input is required, only the chemical symbols. X-ray lines employed, and the accelerating voltage being necessary in addition to the raw X-ray intensities. All constants such as atomic weights, critical excitation potentials, X-ray wavelengths, and absorption coefficients are stored or calculated internally, which reduces the errors and time associated with looking up and key-punching these values. New fluorescent yields are used for K and L radiation. No fluorescence correction is made for M radiation. The use of this correction program generally gives results, accurate to about 2 to 4%, relative to the amount present. For films thinner than 2500 Å, a new model is proposed which allows the X-ray spectra from the film and substrate to be unfolded to give the composition of the film only. To accomplish this, the atomic number correction of Duncumb and deCasa employed in MAGIC has been used in conjunction with a mean electron energy concept. Results obtained to date through the use of this model have been surprisingly good, being of the order of 5% relative to the amount present. Potential errors and uncertainties are discussed, and results given which illustrate the accuracy of the two methods.

Type
Research Article
Information
Advances in X-Ray Analysis , Volume 11: Sixteenth Annual Conference on Applications of X-ray Analysis, August 9-11, 1967 , 1967 , pp. 287 - 305
Copyright
Copyright © International Centre for Diffraction Data 1967

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Colby, J. W. and Wonsidler, D. R., “Stoichiometry of Thin Insulating Films,” paper presented at Dallas Electrochemical Society Meeting, May, 1967.Google Scholar
2. Anderson, C. A., “Electron Probe Microanalysis of Thin Layers and Small Particles with Emphasis on Light-Element Determinations,” in: T. D. McKinley, K. F. J. Hcinrich, and D. B. Wittry (eds.). The Electron Microprobe, John Wiley & Sons, Inc., New York, 1966, p. 58.Google Scholar
3. Poole, D. M. and Thomas, P. M., “Quantitative Electron-Probe Microanalysis,” J. Inst. Metals 90: 288, 1962.Google Scholar
4. Duncumb, P. and Shields, P. K., “The Present State of Quantitative X-Ray Microanalysis, Part I: Physical Basis,” Brit. J. Appl. Phys. 14: 617, 1963.Google Scholar
5. Green, M. and Cosslett, V. E., “The Efficiency of Production of Characteristic X-Radiation in Thick Targets of a Pure Element,” Proc. Phys. Soc. (London) 78: 1206, 1961.Google Scholar
6. Bethc, H. A., “Zur Theorie des Durchgangs Schneller Korpuskalarstrahlen durch Matetie,” Ann.Physik 5: 325, 1930.Google Scholar
7. Nelms, A. T., “Energy Loss and Range of Electrons and Positron,” Natl. Bur. Std. (U.S.),Circ. 577, 1956, and Suppl. Circ. 577, 1958.Google Scholar
8. Duncumb, P. and deCasa, C., “Atomic Number and Absorption Corrections: Accuracy Obtained in Practice,” paper presented at the 2nd Natl. Conf, on Electron Microprobe Analysis, Boston, Mass., 1967.Google Scholar
9. Duncumb, P., Private communication, 1966.Google Scholar
10. Bishop, H. E., “Some Electron Backscattering Measurements for Solid Targets,” in: X-Ray Optics and Microanalysis, Hermann, Paris, 1967.Google Scholar
11. Smith, J. V., “Production of X-Rays,” notes from course, Microprobe Analysis, University of Chicago, 1965.Google Scholar
12. Duncumb, P. and Shields, P. K., “Effect of Critical Excitation Potential on the Absorption Correction,” in: T. D. McKinley, K. F. J, Heinrich, and D. B. Wictry (eds.), The Electron Microprobe, John Wiley & Sons, Inc., New York, 1966.Google Scholar
13. Philibert, J., “A Method for Calculating the Absorption Correction in Electron-Probe Microanalysis,” in; H. H. Pattec, V. E. Cosslett, and A, Engstrom (eds.), X-Ray Optics and X-Ray Microanalysis, Academic Press, New York, 1963, p. 379.Google Scholar
14. Heinrich, K. F. J., “The Absorption Correction Model for Microprobe Analysis,” paper presented at 2nd Natl. Conf. on Electron Microprobe Analysis, Boston, Mass., 1967.Google Scholar
15. Reed, S. J. B., “Characteristic Fluorescence Corrections in Electronprobe Microanalysis,” Brit. J. Appl. Phys. 16: 913, 1965.Google Scholar
16. Heinrich, K. F. J., “X-Ray Absorption Uncertainty,” in: T. D. McKinley, K. F. J. Heinrich, and D. B. Wittry (eds.), The Electron Microprobe, John Wiley & Sons, Inc., New York, 1966, p. 296.Google Scholar
17. Burhop, E. H. S., “Le Rendement de Fluorescence,” J. Phys. Radium 16: 625, 1955.Google Scholar
18. Fink, R. W., Jopson, R. C., Mark, H., and Swift, C. D., “Atomic Fluorescence Yields,” Rev. Mod. Phys. 39: 513, 1966.Google Scholar
19. Castaing, R., “Electron Probe Microanalysis,” in: Advttn. Electron. Electron Phys. 13: 317, 1960.Google Scholar
20. Cosslett, V. E. and Thomas, R. N., “Penetration and Energy Loss of Electrons in Solid Targets,” in: T. D” McKinley, K. F. J. Heinrich, and D. B. Wittry (eds.), The Electron Microprobe, John Wiley & Sons, Inc., New York, 1966, p. 248.Google Scholar
21. Cosslett, V. E. and Thomas, R. N., “Multiple Scattering of 5-30 keV Electrons in Evaporated Metal Films II : Range-Energy Relations,” Brit. J. Appl. Phys. 15: 1283, 1964.Google Scholar
22. Hart, R. K. and Pilncy, D. G., “Effect of Spectral Line Shift on Microprobe Data,” paper presented at 2nd Natl, Conf. on Electron Microprobe Analysis, Boston, Mass., 1967.Google Scholar
23. Colby, J. W., Wise, W. N., and Conley, D. K.,” Backscatter and Secondary Electron Measurements in the Microprobe Analyzer,” in: J. B. Newkirk and G. R. Mallett (eds.), Advances in X-Ray Analysis, Vol. 10. Plenum Press, New York, 1967, p. 447.Google Scholar
24. Brown, D. B. and Wittry, D. W., “A Transport Equation Program and its Application to Electron Microprobe Analysis,” paper presented at 2nd Natl, Cong, on Electron Microprobe Analysis, Boston, Mass., 1967.Google Scholar
25. Kirianenko, A., Maurice, F., Calais, D., and Adda, Y., “Analysis of Heavy Elements (Z 80) with the Castaing Microprobe: Application to the Analysis of Binary Systems Containing Uranium,” in: H. H. Pattee, V. E. Cosslett, and A. Engstrom (eds.), X-Ray Optics and X-Ray Microanalysis, Academic Press, New York, 1963, p. 559.Google Scholar
26. Henoc, J., “Contribution to Electron Probe Microanalysis,” Thesis, Paris, 1962.Google Scholar