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US 8,408,448 B1Granted
Forming constant diameter spherical metal balls
AssigneeInternational Business Machines Corporation
InventorsClaudius Feger, Peter Alfred Gruber, Mark Harrison McLeod, Jae-Woong Nah
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Abstract
A process and tools for forming spherical metal balls is described incorporating molds, injection molded solder, a liquid or gaseous environment to reduce or remove metal oxides and an unconstrained reflow of metal in a heated liquid or gas and solidification of molten metal in a cooler liquid or gas.
Claims10
A method for forming spherical metal balls comprising:
- filling cavities in a mold with molten metal;
- cooling said molten metal to a solid in said cavities in said mold;
- selecting a plate having cavities having openings facing openings of said cavities in said mold;
- said cavities in said plate larger than said corresponding facing cavities in said mold;
- filling said cavities in said plate with a liquid for removing metal oxides;
- placing said cavity openings of said mold facing downwards and above said corresponding cavity openings facing upwards in said plate;
- heating said mold and plate above a metal melting temperature to reflow said metal whereby said metal is released from said cavity in said mold and passes into said liquid in said corresponding facing cavity in said plate, said metal being unconstrained in said liquid forming spherical metal balls due to metal surface tension;
- and
- cooling said spherical metal balls below said melting temperature to form solid spherical metal balls.
6 more elements
Dependencies are inferred from the claim text.