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. 29, 1984
Filed:
Jul. 24, 1981
Kenneth C Smith, Cambridge, GB;
National Research Development Corporation, London, GB;
Abstract
The fabrication of a microcircuit by beam lithography requires an economic distribution of processing time between the high resolution portions of the exposure pattern and areas of much lower resolution. At least one ion beam provides the high resolution performance and at least one electron beam satisfies the lower resolution requirement. The beams are independently operable and are relatively inclined for substantial convergence at the substrate. The convergence is such that all beams can be scanned simultaneously in a single elemental area of substrate or in adjacent elemental areas which are presented for exposure in sequence. For registration the substrate is imaged by electron scanning and the positions of registration marks are related in the image to predetermined positions which represent the required position of the substrate. A positional correction signal is derived by observation of image brightness, size and orientation at the predetermined positions. The signal is processed by a computer which holds all positional control and scan control data and instructs the relevant controls.