The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 10, 1995
Filed:
Dec. 23, 1993
Steven G Barbee, Dover Plains, NY (US);
Tony F Heinz, Chappaque, NY (US);
Richard J Lebel, Sheldon, VT (US);
Leping Li, Poughkeepsie, NY (US);
Victor J Silvestri, Hopewell Junction, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus for measuring with monolayer sensitivity in real-time the condition of a sample, includes a device for producing a modulated and collimated, p-polarized excitation light beam, a device for directing the p-polarized beam to a surface of the sample such that an angle of incidence of the p-polarized light beam with respect to the normal of the surface is at the Brewster angle, first and second reflecting devices between which the sample is positioned, a mechanism for adjusting a distance between the first and second reflecting devices to adjust a number of interactions of the p-polarized excitation light beam with the sample surfaces, and a detector for detecting the p-polarized light beam output intensity distribution with respect to frequency front the sample surfaces. The reflecting devices and the sample are adjustably maintained parallel to one another to thereby maintain the Brewster angle of the input excitation light beam with respect to the normal of the sample surface. As a result, loss of light intensity due to reflections at the sample surfaces is minimized, interference or noise can be minimized, and a high signal-to-noise ratio is achieved. With the structure and method of the invention, a real time non-destructive device and method for the detection of species on the sample surface are provided which enable the determination of a critical endpoint with monolayer resolution and the presence (or absence) of impurities detrimental to the process yield in a fabrication process. The obtained real-time information of the surface condition can be used to control the wafer processing control devices, thereby achieving closed-loop wafer process control.