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:
Oct. 11, 1994
Filed:
Aug. 20, 1993
Tokyo Electron Kabushiki Kaisha, Tokyo, JP;
Tokyo Electron Tohoku Kabushiki Kaisha, Esashi, JP;
Abstract
A device for detecting a semiconductor wafer in a non-contact manner irrespective of transparency or opacity thereof. At positions corresponding to a plurality of wafers loaded on a carrier, a plurality of light emitting/receiving sensors and a plurality of light receiving sensors are correspondingly provided in pairs in such a manner that their respective light emitting/receiving surfaces and their respective light receiving surface in pairs confront each other. The light emitting/receiving sensors and light receiving sensors are alternately arranged in two rows lengthwise on a sensor support board. In the case of a transparent wafer, a light sent out from a light emitting section of the light emitting/receiving sensor strikes on and is reflected by the surface of the wafer. The thus reflected light is then detected by a light receiving section of the same light emitting/receiving sensor. In the presence of an opaque wafer, a light sent out from the light emitting/receiving sensor is not permitted to reach the confronting light receiving sensor. Conversely, in the absence of the opaque wafer, the light reaches the light receiving sensor for detection. On the other hand, there is provided a judgment section switchably inputting one of a light reception signal generated at the light receiving section of the light emitting/receiving sensor and a light reception signal generated at the light receiving section of the light receiving sensor.