-
公开(公告)号：DE2965298D1
公开(公告)日：1983-06-01
申请号：DE2965298
申请日：1979-10-31
Applicant: IBM
Inventor： GASTON CHARLES ARDEN , KIRK JOSEPH PENNELL , WASIK CHESTER ALEXANDER
IPC: G01B11/06
Abstract: An optical system and technique for monitoring a monotonic change in the thickness of a transparent film by means of optical interference, and for eliminating ambiguity in the identification of absolute film thickness. The system is particularly adapted for monitoring the etching of a dielectric film of uncertain initial thickness in microelectronic fabrication. The technique utilizes a white light source directed upon the film. Reflected light, modified by optical interference in the dielectric film, is monitored by photodetectors at two distinct wavelengths. The cyclic patterns of intensity change at the two wavelengths are compared to identify unambiguously the absolute thickness of the film, although the initial uncertainty in film thickness may have corresponded to several cycles of either wavelength pattern alone. To simplify phase comparison of the two cyclic patterns, wavelengths can be selected so that some particular coincidence of extrema in the two signals occurs at a film thickness less than the expected minimum initial thickness, and does not occur at any greater thickness up to and including the expected maximum. Determination of the absolute film thickness in this way permits further tracking of the etching process to the desired end point without overshoot.
-
公开(公告)号：DE2960649D1
公开(公告)日：1981-11-12
申请号：DE2960649
申请日：1979-12-10
Applicant: IBM
Inventor： KIRK JOSEPH PENNELL
-
公开(公告)号：DE2962243D1
公开(公告)日：1982-04-01
申请号：DE2962243
申请日：1979-11-27
Applicant: IBM
Inventor： KIRK JOSEPH PENNELL , PREDATSCH JOSEF , SU LO-SOUN
Abstract: 1. An optical measuring device for determining the spacing between edge-shaped structures on surfaces, especially of line widths, characterized in that focused light from a source (18) is moved along a line across the surface (12) to be tested and the light scattered at the edges is detected by means of two photodetectors (60, 62) arranged symmetrically to the optical axis, and that an electronic evaluator circuit (70) is provided for determining the desired spacing between two edge-shaped structures from the position of the peaks of the signals generated by the two photodetectors.
-
公开(公告)号：DE2442888A1
公开(公告)日：1975-06-05
申请号：DE2442888
申请日：1974-09-07
Applicant: IBM
Inventor： KIRK JOSEPH PENNELL
Abstract: A laser is disclosed with a single, critical surface Brewster window. The Brewster window is formed by a Littrow prism having a first planar surface located along the principal optical axis of the laser and oriented at Brewster's angle with respect thereto, for admitting a refracted, plane polarized component of the laser beam. The Littrow prism has a second substantially planar face which does not require the conventional, high quality "laser polish." This second face intersects the first face along a line perpendicular to the principal axis, at an angle with respect to the first face such that the second face is substantially perpendicular to the refracted component of the laser beam. A planar mirror mounted by means of a layer of index matching optical cement, is mounted on the second face of the Littrow prism, perpendicular to the direction of propagation of the refracted, plane polarized component. This component is reflected back upon its self and out of the first planar face of the prism along the principal axis of the laser, whereby laser action is sustained. An alternate embodiment is disclosed where the laser path is folded upon itself and a 45 DEG -90 DEG triangular prism is employed for communicating the laser beam between the two legs of the system, via the Littrow prism. A third embodiment is disclosed of a folded path gaseous discharge laser having an improved optical efficiency and power output.
-
-
-
Search Results
4
records
(took 0.017 seconds)
