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:
May. 08, 1979
Filed:
May. 16, 1977
Christian Lietar, Morges, CH;
Pierre Jeannin, Morges, CH;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
Small reference marks near two corners of a circuit chip in the form of optical gratings in which the grating lines of both reference marks are parallel are illuminated alternately by a laser beam which is projected in the location the reference marks would have if the chip is properly located. Detectors are arranged to pick up the first secondary maximum of each diffraction pattern when the chip is properly located on its carrier plate. Failure of the detectors to respond indicates a chip that must be removed. With a beam-splitting arrangement producing four closely bunched light spots, straddling each of the reference marks, and an appropriate number of detectors, directional error signals are obtainable by which mechanical correction movements can be controlled for automatic localization of the chip. The gratings may be produced at the same time as the integrated circuit as among the surface features of the chip or they may be impressed into the solder beads at the corners of the chip by which the chip is made fast to the carrier plate.