Method of forming a lead-free bump and a plating apparatus therefor

US20050279640A1Inactive Publication Date: 2005-12-22SHIMOYAMA MASASHI +4
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
SHIMOYAMA MASASHI
Publication Date
2005-12-22
Estimated Expiration
Not applicable · inactive patent

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Abstract

The present invention relates to a lead-free bump with suppressed formation of voids, obtained by reflowing a plated film of Sn—Ag solder alloy having an adjusted Ag content, and a method of forming the lead-free bump. The lead-free bump of the present invention is obtained by forming an Sn—Ag alloy film having a lower Ag content than that of an Sn—Ag eutectic composition by plating and reflowing the plated alloy film.
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Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a lead-free bump and a method of forming the same, and more particularly to a lead-free bump with suppressed formation of voids, obtained by reflowing a plated film of Sn—Ag solder alloy having an adjusted Ag content, and a method of forming the lead-free bump, and also to a plating apparatus for forming such a lead-free bump.

[0003] 2. Description of the Related Art

[0004] In surface mounting technology of semiconductor devices or the like, it is very important to carry out soldering with high reliability. Although an eutectic solder containing lead (Sn:Pb=63:37) has heretofore been used widely in soldering, in the light of environmental contamination and because of the problem of α-rays generation from lead, development of lead-free soldering is under way.

[0005] For example, lead-free soldering by means of printing or electroplating is being studied. With printing, however, there ...

Claims

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