Metal fusion bonding – Including means to force or clamp work portions together... – Work portion comprises electrical component
Reexamination Certificate
2002-01-14
2003-05-13
Elve, M. Alexandra (Department: 1725)
Metal fusion bonding
Including means to force or clamp work portions together...
Work portion comprises electrical component
C228S009000, C228S045000
Reexamination Certificate
active
06561408
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a bonding head for mounting electronic components to a circuit board and, a component mounting apparatus with the bonding head.
Conventionally, a spherical bearing is used as an example of parallel adjustment devices for the aforementioned bonding head. The spherical bearing can adjust parallelism of the bonding head by making a pressing tool of the bonding head follow an object such as a bonding stage or the like, thereby facilitating parallel adjustment.
One example of the bonding heads employing the spherical bearing in a parallel adjustment part will be described below with reference to drawings.
FIG. 9
is a perspective view of the conventional bonding head and
FIG. 10
is a sectional view of the bonding head. In these
FIGS. 9 and 10
, a spherical part
2
of a bonding head
1
is constituted so that a block
3
with a convex-shaped spherical part and a block
4
with a concave-shaped spherical part are to be brought in contact with each other. The block
3
is sucked and held to the block
4
by sucking the air to suction grooves
5
through a suction passage
6
formed in the block
4
. Also the block
3
is attracted to the block
4
by a magnetic force of magnets
7
fitted to the block
4
. To the block
3
is connected a cooling fin
8
. A holder
9
coupled to the cooling fin
8
has a pressing tool
10
at a lower end of the holder, to which are inserted a heater
11
and a thermocouple
12
from the same direction. The holder
9
is accordingly heated by the heater
11
while its temperature is monitored by the thermocouple
12
. A point “a” of the center of a lower face of the pressing tool
10
is made the center of a sphere of the spherical part
2
. An electronic component
13
is mounted onto a circuit board
15
via a thermosetting adhesive
14
. The circuit board
15
is placed on a bonding stage
16
.
The bonding head in the above constitution operates as follows.
A bonding operation will be discussed in the first place.
The electronic component
13
is temporarily positioned on the circuit board
15
via the adhesive
14
in a precedent process. The circuit board
15
with the electronic component
13
temporarily positioned thereto is transferred by an outside transfer device not shown in the drawings and fixedly placed on the bonding stage
16
. The bonding head
1
is lowered by an external driving device not shown in the drawings thereby pressing the electronic component
13
by the pressing tool
10
. Since the pressing tool
10
is heated by the heat of the heater
11
via the holder
9
at this time, the heat of the pressing tool
10
is conducted to the adhesive
14
via the electronic component
13
. As a result, setting of the adhesive
14
proceeds to complete joining the electronic component
13
and the circuit board
15
. It is important to secure a high parallelism here between the electronic component
13
and the circuit board
15
so as to obtain a high quality of the joining. In other words, a parallelism between the pressing tool
10
and the bonding stage
16
is crucial for high-quality bonding.
An operation of adjusting the parallelism will now be described with reference to FIG.
10
. The parallelism adjustment operation is carried out when it becomes necessary to replace the pressing tool
10
according to types of products to be produced. The parallelism adjustment operation is carried out without works, i.e., the electronic component
13
and the circuit board
15
loaded on the bonding stage
16
. Although the work is illustrated in
FIG. 10
, actually no work is present during the parallelism adjustment operation.
Before the parallelism adjustment operation, the air is sucked through the suction passage
6
, whereby the block
3
is sucked and held to the block
4
by an air suction force at the suction grooves
5
.
In the parallel adjustment operation, a compressed air is first supplied to the suction passage
6
to release the above suction and holding to the block
3
, while the block
3
is prevented from dropping because of a force of magnets
7
acting to hold the block
3
. Consequently a gap of several—several tens &mgr;m is generated between the block
3
and the block
4
at the spherical part. The block
3
is rendered freely rotatable centering the point “a”. On the other hand, since the holder
9
has the heater
11
and the thermocouple
12
equipped thereto in the same direction along a direction “b” as mentioned before, a turning moment in a direction “c” is given rise to the holder
9
by effects of weights of the heater
11
and the thermocouple
12
and drags of wiring lines
17
and
18
. A lower part
19
of the bonding head which is made rotatable as above eventually comes to incline as shown in FIG.
11
.
Then the bonding head
1
is moved down by the external driving device not shown in the drawings to press the pressing tool
10
to the bonding stage
16
. The pressing tool
10
tends to follow the bonding stage
16
at its pressing face, hence rotating the block
3
about the point “a”. After the rotation, the block
3
is sucked and held to the block
4
through suction of the air from the suction grooves
5
.
In the bonding head
1
constituted as above, when the pressing tool
10
is to follow the bonding stage
16
, drags of the wiring lines
17
and
18
of the heater
11
and the thermocouple
12
and weights of the heater
11
and the thermocouple
12
adversely effect to generate the drag to hinder the pressing tool from tracing the bonding stage. In consequence of this, a sufficient parallelism of the electronic component
13
to the circuit board
15
cannot be secured in the bonding operation. Thus, a contact state of electrodes between the electronic component
13
and the circuit board
15
varies. High-quality bonding cannot achieve in the conventional art.
SUMMARY OF THE INVENTION
The present invention is devised to solve the above problem and has for its object to provide a bonding head in which a pressing face can be arranged to a bonding stage with a higher parallelism than in the conventional art, and a component mounting apparatus with the bonding head.
In order to accomplish the aforementioned objective, according to a first aspect of the present invention, there is provided a bonding head for pressing a component to a circuit form object with a pressing face brought in contact with the component, which comprises:
a pressing part having the flat pressing face which comes in contact with the component on a circuit form object placed on a stage face of a bonding stage;
a supporting part for supporting the pressing part while allowing the pressing part to freely swing; and
an inclination prevention member for preventing the pressing part from inclining to the supporting part in consequence to the swing of the pressing part so as to make the pressing face nearly parallel to the stage face.
As described above, the bonding head of the first aspect of the present invention is provided with the inclination prevention member. The pressing part is prevented by the inclination prevention member from inclining to the supporting part, so that the pressing face is made nearly parallel to the stage face. Therefore the pressing face can be arranged with a higher parallelism to the bonding stage in comparison with the conventional art. Thus components and a circuit form object can be bonded with the high bonding quality.
The above inclination prevention member may be constituted of a heating member for heating the component, which is included in the pressing part, and includes a heating element for heating the pressing face and a heat detector for detecting heat caused by the heating element thereby controlling a temperature of the heating element, to which the heating element and the heat detector are loaded with directions to offset the swing of the pressing part brought about by the heating element and the swing of the pressing part brought about by the heat detector.
The inclination of the pressing part to the supporting part ca
Hosotani Naoto
Maeno Mitsuo
Nasu Hiroshi
Nishikawa Hidenobu
Ono Shuji
Cooke Colleen
Elve M. Alexandra
Wenderoth , Lind & Ponack, L.L.P.
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