Metal fusion bonding – Including means to apply flux or filler to work or applicator – Solid flux or solid filler
Patent
1994-10-11
1995-11-21
Heinrich, Samuel M.
Metal fusion bonding
Including means to apply flux or filler to work or applicator
Solid flux or solid filler
228246, 228224, 221211, B23K 300, B23K 306
Patent
active
054679133
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solder ball supply device which can supply a large number of preliminary solder balls, which are used for fixing tip parts of surface-mount-type to substrates, to the substrates at one time.
2. Background Technology
Along with advance in technologies in recent years, ICs are highly integrated than ever and there is a tendency of increase in the number of input and output terminals on the ICs. These input and output terminals are also miniaturized due to miniaturization of IC chips. Such input and output terminals are fixed on the four corners of IC packages or provided on the back of the packages.
In the case of IC chips having input and output terminals on the back of a package, a number of plated through-holes are provided on the back. Preliminary solder is supplied to the plated through-holes to fix the input and output terminals to the circuit board by the solder to ensure conductivity between them.
One method of supplying solder to plated through-holes on the back of packages is printing a creamy solder by screen printing. Another method comprises taking solder balls out of a storage section using a vacuum pick-up instrument, dipping these solder balls in a flux, and supplying them to the circuit board (U.S. Pat. No. 5,088,639).
The screen printing involves solder-drawing, a phenomenon in which a viscous creamy solder is drawn when screen is peeled off. Because some projections produced by the creamy solder are too small or too large, it is difficult to constantly supply a prescribed amount of solder cream. If the projections are too large, the amount of the solder cream is large and this solder cream may contact the other creamy solder in the narrowly pitched input and output terminals. This may cause short circuit between electrodes.
On the other hand, because the method proposed by U.S. Pat. No. 5,088,639 retains solder balls in a storage section, solder balls may not be sufficiently adsorbed by the vacuum pick-up instrument, if the number of balls to be picked-up are large when these are taken out from the storage section.
In addition, because in this method the solder balls are dipped in a flux as they are adsorbed in the vacuum pick-up instrument, the flux may be adhered to adsorption nozzles of the vacuum pick-up instrument. This may cause malfunction in adsorption of solder balls, and requires frequent cleaning of vacuum pick-up instrument.
An object of the present invention is therefore to provide a solder supply method without these problems, particularly, a solder supply method by which a large number of solder balls can be certainly supplied without causing adhesion of flux to the vacuum pick-up instrument.
DISCLOSURE OF THE INVENTION
The solder ball supply device of the present invention comprises a discharger in which solder ball holding cavities are provided matrixwise, a head section with a number of air suction holes provided at the same pitch as the solder ball holding cavities in the discharger, and a solder ball supply means which takes out a large number of solder balls at one time from solder ball holding cavities at the head section to transfer and supply them to the substrate boards. This construction ensures rapid supply of solder balls, significant improvement in the workability, and mass-production. In addition, the structure in which solder balls are stored matrixwise in the discharger makes it possible for the solder ball supply device of the present invention to be adaptable to a variety of patterns.
The solder ball supply device of the present invention may be further equipped with a flux dispenser in which nozzles are provided in the same pattern as the air suction holes in the head section of solder ball supply means, and which supplies flux onto the boards at one time prior to the supply of the solder balls. This construction can prevent the flux from being adhered to the solder ball head, thus preventing malfunction of the nozzles in the adsorption of solder balls.
Furthermor
REFERENCES:
patent: 4558812 (1985-12-01), Bailey et al.
patent: 5205896 (1993-04-01), Brown et al.
patent: 5279045 (1994-01-01), Odashima et al.
patent: 5284287 (1994-02-01), Wilson et al.
Ibuki Yoshiteru
Iguchi Norio
Namekawa Masatoshi
Okuno Masatoshi
Citizen Watch Co. Ltd.
Heinrich Samuel M.
Miyota Co., Ltd.
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