Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2002-04-01
2003-09-02
Whitehead, Jr., Carl (Department: 2813)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S582000, C156S297000
Reexamination Certificate
active
06613180
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for fabricating a semiconductor-mounting body comprising a semiconductor device mounted on a substrate and an apparatus for fabricating a semiconductor-mounting body.
2. Related Art of the Invention
As the fining art of a semiconductor process advances, the form of a semiconductor package is also developed from QFP to &mgr; BGA and CSP (chip size package), and moreover flip-chip mounting of directly connecting a semiconductor bare chip onto a substrate.
Above all, in the case of the flip-chip mounting, because a semiconductor device and a substrate are directly mounted, application development to units requiring a high-speed processing may be further accelerated. To realize the above mounting art, a mounting-process art is indispensable and a fabrication equipment and a process art for joining a semiconductor device with a substrate so that the reliability can be secured in a short time are particularly important.
A case of performing mounting by using the flip-chip mounting art is described below by referring to the accompanying drawings.
FIG. 10
is an illustration for explaining the configuration of a structure in which a semiconductor device is flip-chip-mounted on a substrate by using a conventional apparatus for fabricating a semiconductor-mounting body and its fabrication procedure and
FIG. 11
is a schematic view for performing flip-chip mounting by setting an elastic body to a position where a heat source contacts a semiconductor device. In
FIGS. 10 and 11
, the same portions are provided with the same symbol.
As shown in
FIG. 10
, a bump
16
having a two-stage protrusion shape is formed on an electrode pad
15
of a semiconductor device
2
by melting an Au wire and then, a conductive adhesive
17
is transferred to the two-stage protruded portion of the bump
16
. Then, the semiconductor device
2
is faced down and joined with a terminal electrode
18
pattern-formed on a substrate
1
to cure the conductive adhesive
17
.
Then, a liquid epoxy-based sealing resin
11
is injected into the gap between the semiconductor device
2
and the substrate
1
and then, as shown in
FIG. 11
, an elastic body
22
is set to the position with which a heat source
7
and semiconductor device
2
contact to cure the sealing resin
11
while pressing the back of the semiconductor device
2
by the elastic body
22
.
A base table
21
is a table to which the substrate
1
is set. Thus, by curing the sealing resin
11
while pressing the semiconductor device
2
at a load larger than the pushing-up force of the semiconductor device
2
due to the thermal expansion when the searing resin
11
is heated, it is possible to minimize increase of a connection resistance or imperfect joining states.
However, there may be no problem about the case in which the substrate
1
is thick and has a thermal expansion coefficient close to that of the semiconductor device
2
and a small number of semiconductor devices
2
are flip-chip-mounted like the case of the conventional configuration shown in FIG.
10
. As shown in
FIG. 11
, however, when flip-chip-mounting the semiconductor devices
2
different from each other in thickness and shape on the substrate
1
, stresses are concentrated on the highest semiconductor device
2
and the highest semiconductor device
2
is greatly damaged, because pressure is inevitably applied from the thickest semiconductor device
2
to lower ones in order.
Even if using a method for absorbing fluctuations in heights of the semiconductor devices
2
by cushions such as elastic bodies
22
A,
22
B, and
22
C at the position where the heat source
7
contacts the semiconductor devices
2
, it is difficult to apply a uniform pressure to the elastic bodies
22
A and
22
C other than the elastic body
22
B because stresses are further concentrated on the elastic body
22
B as the thickness fluctuation of the semiconductor devices
2
increases.
Moreover, a position shift may occur in the semiconductor devices
2
due to the elastic deformation of the elastic body
22
B.
Furthermore, when many semiconductor devices
2
having different thicknesses and shapes are present on the substrate
1
, it is necessary to set the above elastic bodies to positions corresponding to all the semiconductor devices
2
. Therefore, a fabrication system is inevitably restricted to a dedicated system for only one type of product. Therefore, in the case of many types of products, it is necessary to use an elastic body for each type of produce each time and thus, there is a problem in versatility.
Therefore, it is difficult to flip-chip-mount many semiconductor devices having different thicknesses and shapes by the conventional fabrication method.
SUMMARY OF THE INVENTION
The present invention is made to solve the above conventional problems and its object is to provide a method for fabricating a semiconductor-mounting body and an apparatus for fabricating a semiconductor-mounting body capable of fabricating a semiconductor-mounting body by substantially uniformly pressurizing a plurality of semiconductor devices having different thicknesses and shapes when mounted on a substrate.
One aspect of the present invention is a method for fabricating a semiconductor-mounting body having at least one semiconductor device mounted on a substrate and a sealing resin set in the gap between the substrate and the semiconductor device, comprising:
a first step of setting a flexibly deformable sheet on a face of the semiconductor device not facing the substrate; and
a second step of generating an air-pressure difference between the side where the semiconductor device is not present and the side where the semiconductor device is present on the basis of the sheet so that the air pressure at the side where the semiconductor device is not present becomes higher than the side where the semiconductor device is present and pressurizing the semiconductor device by the sheet after the first step.
Another aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein at least a part of the sheet does not contact the substrate in the second step.
Still another aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the second step is executed by supplying predetermined gas to the side of the sheet where the semiconductor device is not present and excluding gas from the side where the semiconductor device is present.
Yet still another aspect of the present invention is the method for fabricating a semiconductor-mounting, wherein the sheet does not contact the semiconductor device and/or the sealing resin at least immediately before the pressurization is performed.
Still yet another aspect of the present invention is the method for fabricating a semiconductor-mounting, further comprising a third step of fixing the circumference of the sheet set on the semiconductor device at least immediately before pressurizing the sheet.
A further aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein looseness is removed from the sheet before pressurizing the sheet.
A still further aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein looseness is removed from the sheet by fixing the circumference of the sheet from the outside to the inside of the sheet in order.
A yet further aspect of the present invention is the method for fabricating a semiconductor-mounting body, further comprising a fourth step of heating the sheet by a heater from the side where the semiconductor device is not present when pressurizing the sheet.
A still yet further aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the distance between the set sheet and the heater is adjusted.
An additional aspect of the present invention is the method for fabricating a semiconductor-mounting body, wherein the sheet is a rubber sheet formed by silicon o
Hayashi Yoshitake
Kojima Toshiyuki
Koyama Masayoshi
Saito Ryuichi
Shibata Osamu
Jr. Carl Whitehead
Schillinger Laura M
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