Metal fusion bonding – Process – Using high frequency vibratory energy
Reexamination Certificate
2001-09-28
2003-06-03
Dunn, Tom (Department: 1725)
Metal fusion bonding
Process
Using high frequency vibratory energy
Reexamination Certificate
active
06572005
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and a method for joining bumps formed at electrodes of an electronic component to electrode portions on a circuit board, and a semiconductor component-manufacturing apparatus provided with the bump-joining apparatus.
In one way for electrically connecting and fixing electronic components onto a circuit board, there is carried out a method whereby bumps formed at electrodes of an electronic component are joined to electrode portions on a circuit board. For instance, a semiconductor component-manufacturing apparatus
1
shown in
FIG. 11
is used to execute the bump-joining method, which roughly comprises a component feed apparatus
2
, a bonding stage
3
, a component reversal apparatus
4
, a bump-joining apparatus
5
and a circuit board transfer apparatus
6
.
The component feed apparatus
2
feeds semiconductor chips as an example of the electronic components, and the circuit board transfer apparatus
6
carries circuit boards in to and out from the semiconductor component-manufacturing apparatus
1
. The bonding stage
3
, where one of the circuit boards carried in by the circuit board transfer apparatus
6
is loaded to be subjected to the joining, can be moved in a Y-direction by a Y-axis robot
7
. The bonding stage
3
heats the circuit board for the joining of bumps. The component reversal apparatus
4
holding one of the semiconductor chips supplied from the component feed apparatus
2
turns the semiconductor chip upside down so that bumps formed at electrodes of the semiconductor chip face the circuit board loaded on the bonding stage
3
. The bump-joining apparatus
5
includes a holding device for holding the semiconductor chip, a Z-directional driving device
51
for moving the held semiconductor chip in a thicknesswise direction of the semiconductor, and an ultrasonic vibration generation device
9
which will be detailed later. The bump-joining apparatus
5
is mounted to an X-axis robot
8
to be moved in an X-direction by the X-axis robot
8
, receiving the semiconductor chip from the component reversal apparatus
4
, transferring the semiconductor chip to the bonding stage
3
, driving the Z-axis driving device
51
thereby pressing the received and held semiconductor chip at a predetermined position of the circuit board loaded on the bonding stage
3
to join the bumps. A positioning of the semiconductor chip to be joined onto the circuit board is carried out by the X-axis robot
8
and Y-axis robot
7
.
The bump-joining apparatus
5
is provided with the ultrasonic vibration generation device
9
which vibrates the bumps in the Y- or X-direction thereby generating heat of friction between the bumps and electrode portions on the circuit board to decrease a heating temperature of the bonding stage and steady the joining of the bumps. The ultrasonic vibration generation device
9
has, as shown in
FIG. 12
, a plurality of layered piezoelectric elements
91
and an ultrasonic horn
92
connected to one end portion of the piezoelectric elements
91
. A vibration, e.g., in the Y-direction brought about when a voltage is impressed to the piezoelectric elements
91
is amplified by the ultrasonic horn
92
. A nozzle
93
for holding of the semiconductor chip is fixed at the other end portion of the ultrasonic horn
92
. The vibration of the piezoelectric elements
91
brings about ultrasonic vibration to the nozzle
93
, i.e., semiconductor chip held by the nozzle
93
. Although the piezoelectric elements
91
vibrate in the Y-direction in
FIG. 12
, while the vibration is conducted to the semiconductor chip, vibrations moving in various directions also occur. Consequently the semiconductor chip is actually vibrated in various directions although primarily vibrated in the Y-direction.
The conventional semiconductor component-manufacturing apparatus
1
constituted as above joins the bumps in a manner described hereinbelow.
The circuit board carried in by the circuit board transfer apparatus
6
is loaded and heated on the bonding stage
3
. In the meantime, the semiconductor chip held by the component reversal apparatus
4
from the component feed apparatus
2
is moved by the bump-joining apparatus
5
to a mount position on the bonding stage
3
. Each of bumps
11
before being joined has a configuration, for example, as shown in FIG.
13
. Specifically, a diameter I of each bump
11
is approximately 100 &mgr;m, a height III of a base portion
11
a
is approximately 30-35 &mgr;m and a total height II of each bump
11
is approximately 70-75 &mgr;m.
Each bump
11
of the configuration is pressed to each electrode portion on the circuit board by the operation of the Z-directional driving device
51
, pressed down as indicated in FIG.
14
and joined. A height IV of the bump
11
in
FIG. 14
when pressed is nearly equal to the height III of the base portion
11
a.
In the conventional semiconductor component-manufacturing apparatus
1
, after the bump
11
is pressed in a state of
FIG. 14
(which will be denoted by a reference numeral
12
hereinafter), the ultrasonic vibration generation device
9
is operated to vibrate each bump
12
with ultrasonic waves and join the pressed bump
12
to each electrode portion of the circuit board.
According to the conventional art described above, each contact-area between each bump
12
and each electrode portion
21
of the circuit board
20
is large because each bump
12
is started to be vibrated only after each bump
11
is pressed to be formed as the bump
12
in FIG.
14
. In consequence, a sufficient scrub or friction cannot be attained in some cases between the bump
12
and electrode portion
21
, resulting in insufficiency of heat of friction necessary for the joining between the bump
12
and the electrode portion
21
. The bump
12
and the electrode portion
21
cannot be joined perfectly, with a resultant decrease in the join strength.
SUMMARY OF THE INVENTION
The present invention is devised to eliminate the above-discussed disadvantage and has for its object to provide an apparatus and a method for perfectly joining bumps and electrode portions of a circuit board with larger joint strength than in the conventional art, and a semiconductor component-manufacturing apparatus including the bump-joining apparatus.
In accomplishing this and other objects, according to a first aspect of the present invention, there is provided a bump-joining apparatus for joining bumps formed at an electronic component to electrode portions on a circuit board, which comprises:
a vibration generation device for generating relative vibrations between the bumps and the electrode portions, with the bumps facing the electrode portions;
a pressing device for moving the electronic component and the circuit board relative to each other in a direction to bring the bumps and the electrode portions close to each other, and pressing the bumps of the electronic component and the electrode portions to each other, so as to compress the bumps; and
a control unit for controlling the pressing device to execute a pressing action control to change a contact-area of each of the bumps to each of the electrode portions through the compressing from an initial contact area corresponding to each of the bumps to a join-completed-contact area corresponding to each of the bumps at the completion of the joining which exceeds the initial contact area, and for controlling the vibration generation device to execute a vibration control to generate constant vibration from a time when the contact-area reaches the initial contact area to a time when the contact-area reaches the join-completed-contact area.
According to a second aspect of the present invention, there is provided a bump-joining method for joining bumps formed at an electronic component to electrode portions on a circuit board, which comprises:
with the bumps facing the electrode portions, performing a pressing operation to press the bumps and the electrode portions relatively so as to compress the bumps so that contact-areas
Higashi Kazushi
Kanayama Shinji
Minamitani Shozo
Takahashi Kenji
Tsujisawa Takafumi
Dunn Tom
Johnson Jonathan
Matsushita Electric - Industrial Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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