Metal fusion bonding – Process – With shaping
Reexamination Certificate
2000-06-14
2002-04-30
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
With shaping
C228S041000, C228S161000
Reexamination Certificate
active
06378756
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to a solder ball arrangement device and, more particularly, to a solder ball arrangement device for use in transferring an array of solder balls onto a mounting board to form an array of bump electrodes in a BGA (ball grid array) technique, a CSP (chip size package) technique, or a flip chip bonding technique. The present invention also relates to a method for fabrication thereof.
(b) Description of the Related Art
Bump electrodes formed by a BGA technique, a CSP technique, and a flip chip bonding technique are increasingly used in mounting a semiconductor chip onto a mounting board. In the recent advance of semiconductor integrated circuits, a large number of external pins are disposed at a smaller pitch, with increased mounting density, reduced device area and increasing capacity of the integrated circuits. In the method for forming bump electrodes by using metallic solder balls, it is especially important to arrange a large number of minute metallic solder balls (hereinafter referred to as solder balls) efficiently at a small pitch. Some proposals have been made for forming the bump electrodes.
JP-A-8(1996)-25035, for example, proposes a solder ball transfer device for installing an array of solder balls on a mounting board.
FIG. 1A
is a schematic cross-sectional view of the proposed solder ball transfer device.
The proposed solder ball transfer device
30
comprises an alignment plate
32
having an array of holes
32
a
each for receiving a solder ball
31
therein and an associated ejecting pin
33
disposed for each of the holes
32
a
for ejecting the solder-ball
31
from the alignment plate
32
. A pattern for the array of the holes
32
a
is made to be exactly equal to the pattern of bonding pads
35
formed on a target mounting board
34
. The ejecting pin
33
is sidably mounted by the alignment plate
32
for protruding from and retracting into an associated slot
32
b
communicated with a corresponding one of the holes
32
a
at the bottom thereof. The ejecting pin
33
is of a tube shape having a communicating hole
33
a
therein communicated with a suction pump not shown in the figure.
In the conventional solder ball transfer device
30
, a solder ball
31
is first disposed in each hole
32
a,
with the alignment plate
32
disposed upside-down. The suction pump is then operated to attract the solder ball
31
to the tip of the ejecting pin
33
through the communication hole
33
a.
Subsequently, the alignment plate
32
is turned by a mechanism so that the solder balls
31
disposed on the bottom of the alignment plate
32
are opposed to the top surface of a mounting board
34
. The ejecting pins
33
are then ejected to thrust the solder balls
31
onto the flux
36
on the respective bonding pads
35
, as shown in
FIG. 1B
, followed by release of the solder balls
31
from the ejecting pins
33
by stopping the suction from the suction pump and subsequent retraction of the ejecting pins
33
. Thereafter, the mounting board
34
is introduced into a reflow furnace, wherein flux
36
is melted to fix the solder balls
31
onto the bonding pads
35
of the mounting board
34
.
It is reported that the conventional solder ball transfer device
30
as described above has an advantage in that the array of the solder balls
31
are transferred to the mounting board
34
with excellent reliability even if the solder ball
31
attracts electrostatic charge and/or moisture. In addition, the solder balls
31
are transferred to correct locations of a mounting board
34
even with the presence of the flux
36
.
The conventional solder ball transfer device has, however, a problem in that the complicated structure of the holes
32
a
and associated slots
32
b
in the alignment plate
32
raises the cost of the device, especially in the case of a high density ball pattern such as having a small pitch as low as 300 &mgr;m with a large number of pads as high as 2000. If the alignment plate is formed by an etching technique for achieving the high density, the alignment plate will suffer from lack of mechanical strength due to a small thickness thereof.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a solder ball transfer device or solder ball arrangement device which has a simple structure and a sufficient mechanical strength and is capable of being fabricated with a low cost.
It is another object of the present invention to provide a method for fabricating the solder ball arrangement device as mentioned above.
The present invention provides a solder ball arrangement device comprising an arrangement plate having an array of through-holes penetrating the arrangement plate, a porous member having first and second surfaces, the first surface being attached to the arrangement plate, the through-holes exposing portions of the first surface, and a housing member for defining an air space together with the second surface of the porous member, the housing member having a nozzle or air outlet communicated with the air space.
The present invention also provides a method for manufacturing a solder ball arrangement device comprising the steps of forming an array of through-holes in a plate, bonding a first surface of the plate onto a porous member for exposing portions of the porous member through the through-holes, and receiving at least the porous member in a housing member having an air nozzle or air outlet to form an air space between the porous member and a portion of the housing member.
In accordance with the solder ball arrangement device of the present invention and manufactured by the method of the present invention, a high density solder pattern can be formed on the arrangement plate and can be transferred therefrom onto a mounting board. The arrangement plate may be made thin enough to allow an etching process for forming the through-holes without suffering from lack of strength thereof because the arrangement plate is supported by the porous member.
The above and other objects, features and advantages of the present invention will be more apparent from the following description, referring to the accompanying drawings.
REFERENCES:
patent: 5425493 (1995-06-01), Interrante et al.
patent: 5601229 (1997-02-01), Nakazato et al.
patent: 5685477 (1997-11-01), Mallik et al.
patent: 5749614 (1998-05-01), Reid et al.
patent: 5762258 (1998-06-01), LeCoz et al.
patent: 5768775 (1998-06-01), Nakazato
patent: 5816482 (1998-10-01), Grabbe
patent: 5839641 (1998-11-01), Teng
patent: 5844316 (1998-12-01), Mallik et al.
patent: 5890283 (1999-04-01), Sakemi et al.
patent: 6095398 (2000-08-01), Takahashi et al.
patent: 64-22049 (1989-01-01), None
patent: 404065130 (1992-03-01), None
patent: 7-283224 (1995-10-01), None
patent: 8-25035 (1996-01-01), None
patent: 9-298355 (1997-11-01), None
patent: 10-22619 (1998-01-01), None
patent: 10308412 (1998-11-01), None
Senba Naoji
Shimada Yuzo
Takahashi Nobuaki
Dunn Tom
NEC Corporation
Stoner Kiley
LandOfFree
Solder ball arrangement device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Solder ball arrangement device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solder ball arrangement device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2912728