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:
Apr. 30, 1991
Filed:
Jun. 29, 1990
Ping Chang, Danville, CA (US);
P A Smith, San Pablo, CA (US);
The BOC Group, Inc., New Providence, NJ (US);
Abstract
The present invention provides an electron beam evaporation source designed so that the size of the impact area of the electron beam on an evaporant will remain essentially constant in any position of the impact area on the evaporant; and thus, the rate of evaporation will remain essentially constant. To this end, a quadrapole comprising a set of two pairs of electromagnets is used to deflect the electron beam. The quadrapoles provide a uniform magnetic deflection field to prevent distortion of the impact area. A pair of pole pieces, used in deflecting the electron beam through an arc of 270 degrees, are provided with a predetermined thickness and spacing to prevent lengthening of the impact area parallel to the pole pieces as the electron beam is deflected parallel to the pole pieces. The pole pieces, however, produce the formation of tail regions in the impact area when the impact area is positioned near the pole pieces. In order to eliminate such tail regions, a pair of surface dipoles are connected to the pole pieces at an angle of 45 degrees such that the electron beam passes between the ends of the dipoles at a near vertical location of the arc of the electron beam. The maintenance of the impact area essentially free of distortion, tail region formation, and lengthening, ensures essential consistency in the size of the impact areas.