Metal fusion bonding – Process – Preplacing solid filler
Reexamination Certificate
1999-04-30
2001-10-09
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Preplacing solid filler
C228S180220
Reexamination Certificate
active
06299058
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a positioning method for attaching a solder ball to an electrical connector and the connector using the same, particularly to a positioning method for obtaining coplanarity of a matrix of solder balls soldered on a bottom face of an electrical connector.
2. The Prior Art
Ball grid array is popular in manufacturing of CPU packages and printed circuit board and it also becomes a trend in manufacturing of an electrical connector. Referring to
FIG. 4
, normally a soldering tail
31
is formed at a lower end of each contact of an electrical connector
1
for engagement with a solder ball
3
via soldering. A mesh (not shown), similar to that used in a screen painting procedure, is used to align the solder balls
3
to corresponding soldering tails
31
of contacts before soldering to a printed circuit board (not shown). However, a solder ball
3
is apt to engage with the soldering tail
31
at an edge thereof during soldering due to its rolling feature. However, any of the solder balls
3
if soldered on the edge of the soldering tail
31
will critically damage the coplanarity of the solder balls thus adversely affecting the soldering of the connector
1
to the printed circuit board. It is requisite to provide a new method by which the solder balls can be soldered onto the right positions thereby guaranteeing the coplanarity of the solder balls when they are soldered on the soldering tails.
SUMMARY OF THE INVENTION
The primary purpose of the present invention is to provide a method for positioning a soldering ball in a center point of a soldering tail during soldering thus guaranteeing the coplanarity of many soldering balls on an electrical connector.
The second purpose of the present invention is to provide an electrical connector attached with a solder ball at a center region of each soldering tail thereof so that all the solder balls are coplanar for facilitating the electrical connector to be mounted on a printed circuit board properly.
In accordance with one aspect of the present invention, a method for positioning a solder ball onto a contact tail of an electrical connector comprises steps of arranging the contact tail into a center region and a peripheral region surrounding the center region. Attach solder paste onto the center region of the contact tail via a first mesh painting procedure. Attach solder resist onto the peripheral region of the contact tail via a second mesh painting procedure. Position a solder ball on the center region of the contact tail via a screen board. Apply a reflow soldering procedure on the solder ball so that the solder ball can be soldered on the solder paste attached to the center region of the contact tail.
In accordance with another aspect of the present invention, an electrical connector comprises an insulative housing defining a plurality of passageways from which contact tails expose to external. Each contact tail is in advance arranged into a center region and a peripheral region surrounding the center region wherein the center region is attached with solder paste via a first painting procedure and the peripheral region is attached with solder resist via a second painting procedure. A solder ball is attached to the solder paste on the center region of the contact tail via a reflow soldering procedure.
REFERENCES:
patent: 5791552 (1998-08-01), Werther
patent: 6025258 (2000-02-01), Ochiai et al.
patent: 6084781 (2000-07-01), Klein
patent: 6109507 (2000-08-01), Yagi et al.
patent: 6169022 (2001-01-01), Saitou
Lau John H.
Lin Scott
Szu Ming-Lun
Chung Wei Te
Dunn Tom
Hon Hai - Precision Ind. Co., Ltd.
Johnson Jonathan
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