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:
Jul. 16, 1996
Filed:
Dec. 01, 1994
Eric M Hubacher, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method for forming conductive bumps (60, 62) on a semiconductor device (50) using a mask structure (20) employs two masks (22, 24) individually fabricated and positioned in a back-to-back relationship. Each mask is patterned and isotropically etched to form a plurality of tapered openings (30, 40) corresponding to a pattern of terminal pads (54) on the semiconductor device. Metal is evaporated through the openings and onto the terminal pads. The mask structure is removed and the remaining metal is reflowed to form the conductive bumps. Using a mask structure having two individual masks (each with a thickness of one-half a typical mask thickness) enables smaller openings to be etched in each mask. Upon joining the two masks, the effective aspect ratio of the mask structure is reduced to produce smaller and denser conductive bumps without loss of volume and height control.