Coated solder spheres and method for producing the same

Abstract

Solder spheres which can avoid blackening during transportation have a substantially uniform coating of a lubricant on the surfaces thereof. They are produced by dipping freshly prepared solder spheres in a lubricant solution with a concentration of from 10 ppm to 1000 ppm followed by collection of the spheres and drying. The lubricant is preferably selected from an aliphatic hydrocarbon lubricant, a higher fatty alcohol or acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and a combination thereof.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to lubricant-coated solder spheres suitable for use in the formation of solder bumps on a substrate for connecting electronic components to the substrate. The invention also relates to a method for coating solder spheres with a lubricant.[0002]As electronic devices have become increasingly light, thin, short, or compact, electronic components used in these devices have been made compact and multi-functional. In order to produce a multi-functional electronic component, it is necessary to assemble a plurality of integrated circuits (IC's) in a single component and form a great number of leads extending from the IC's.[0003]Examples of such multi-functional electronic components include QFP's (Quad Flat Packages) and SOP's (Small Outline Packages), which have leads projecting from all four sides or from two opposing sides, respectively, of a square or rectangular body. These electronic components, however, are limited in the...

AI Technical Summary

Benefits of technology

The patent text describes a solution to prevent scraping and blackening of solder spheres during shipping and handling. The solution involves improving the slip properties of the solder spheres by coating them with a lubricant. This makes the solder spheres easier to move and release from the mounter, and reduces the likelihood of injury and surface scraping. The technical effect of this patent is to improve the reliability and quality of solder spheres during shipping and handling.

Problems solved by technology

Therefore, shaking, swinging, or vibrating of a large number of solder spheres in a container may cause those solder spheres which are in contact with the container wall or with one another to be rubbed without good slippage, thereby resulting in scraping of the surfaces of the solder spheres, which causes blackening of the solder spheres.

The soft solder spheres tend to be bitten by the edges of the suction ports of the mounter and such solder spheres do not readily fall down from the suction ports by application of a moderate shock or reverse injection of air to the suction head when they are to be released from the mounter.

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