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:
Nov. 26, 2002
Filed:
Jan. 28, 2002
Yang-Tung Fan, Jubei, TW;
Hsiu-Mei Yu, Hsin-Chu, TW;
Li-Hsin Tseng, Taichung, TW;
Kuang-Peng Lin, Hsin-Chu, TW;
Ta-Yang Lin, Changhua, TW;
Taiwan Semiconductor Manufacturing Company, Hsin-chu, TW;
Abstract
The present invention teaches how greater solder ball height can be achieved without the need to sacrifice areal density. The mold in which the solder is formed, is created in two steps. In a first exposure, a negative photoresist (preferably DFR) is patterned to form a conventional cylindrical mold. However, exposure and development time are adjusted in such a way that a layer of unexposed and undeveloped resist of reduced thickness remains covering the floor of the mold. This residual resist layer is given a second exposure and, after development, forms an annular insert in the bottom of the first mold. After the mold has been filled with solder (either through electroplating or by using solder paste) it is removed, the result being a solder bump made up of two contiguous coaxial cylinders the upper one having the larger diameter. After remelt, bumps having this shape form oblate spheroids rather than spheres.