Metal fusion bonding – With means to juxtapose and bond plural workpieces – Plural discrete workpieces
Reexamination Certificate
2002-01-23
2003-06-24
Dunn, Tom (Department: 1725)
Metal fusion bonding
With means to juxtapose and bond plural workpieces
Plural discrete workpieces
C228S012000, C228S049500, C228S103000, C228S105000, C156S379000, C156S538000
Reexamination Certificate
active
06581817
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a die bonding device used when mounting electronic components, such as semiconductor laser crystals, or the like, onto a stem.
BACKGROUND ART
In the prior art, Japanese Patent Application Laid-open No. Hei 7-321410 discloses the mounting a semiconductor laser crystal on a stem. Moreover, the operation of mounting fine components of this kind, such as semiconductor laser crystals, or the like, onto stems is performed by manual operation using tweezers, and the like, while magnifying the mounting region through use of an magnifying scope.
However, since the mounting of fine components is performed manually while looking through a magnifying scope, as described above, a great deal of the operation depends on the skill of the operator, and this is problematic in relation to improve the efficiency of the mounting operation.
SUMMARY OF THE INVENTION
The present invention is devised in order to resolve the aforementioned problems, an object thereof being to provide a die bonding device whereby automation can be achieved in installing electronic components onto stems.
The die bonding device relating to one aspect of the present invention is a die bonding device for mounting an electronic component on a metal stem, characterized in that it comprises: a bonding nozzle for suctioning the electronic component and positioning the electronic component on a component mounting face of the stem; a stem carrying head for carrying the stem; a heater section for heating while the electronic component positioned on the component mounting face of the stem to mount said electronic component on said stem; and an imaging camera having a light axis extending through the component mounting face of the stem when positioned inside the heater section, which performs reciprocating motion in the direction of the light axis.
In this die bonding device, the metal stem is suctioned by the stem carrying head and positioned (fixed) in the heater section. The electronic component suctioned to the bonding nozzle in a prescribed position is conveyed to the stem and positioned on the component mounting face. Solder material placed between the component mounting face and the electronic component is then caused to melt in the heater section, and when it subsequently solidifies, the electronic component becomes fixed to the stem, but before performing this heating inside the heater section, it is necessary to position the electronic component suctioned onto the bonding nozzle accurately on the component mounting face. Therefore, it is necessary accurately to recognize the position of the component mounting face before mounting, and for this purpose, an imaging camera is used in the present invention, but the finer the electronic component that is to be recognized, the greater the degree to which the imaging camera is required to magnify the component mounting face. Moreover, although the imaging camera performs reciprocating motion in order to avoid collision with the bonding nozzle, the deviation in the imaging position of the camera in this case has some effect on the mounting of the component. Therefore, rather than performing reciprocating motion so as to avoid the bonding nozzle to the side thereof, the imaging camera makes use of the object depth of field of the lens to perform reciprocating motion in the direction of the light axis passing through the component mounting face. Thereby, it is possible for the movement error inevitably generated when the imaging camera performs reciprocating motion mechanically to be absorbed within the object depth of field, and hence accurate imaging can be achieved using a simple composition, and particularly beneficial effects can be displayed when the predicted component mounting region is very fine, and when the imaging camera has to be moved. The light axis may intersect with the component mounting face of the stem in a perpendicular fashion, or it may intersect therewith obliquely.
Furthermore, desirably, the heater section is disposed to the side of the stem carrying head, and the stem carrying head comprises a pin insertion hole into which stem pins extending from the stem base of the stem are inserted, and rotates through 90° between a state where the pin insertion hole is facing upwards and a state where it is facing sideways. In this case, since a 90° rotatable structure is adopted for the stem carrying head, the stem pins of the stem are able to drop down from above into the pin insertion hole of the stem carrying head. The stem carrying head can then be rotated through 90° to assume a horizontal position, while the stem is mounted therein, and hence the component mounting face can be made to face towards the imaging camera.
Furthermore, desirably, the stem carrying head comprises: a stem base receiving section for supporting the circumference of the stem base of the stem, provided at the vertex portion of the stem carrying head; and a pressing hook for pressing against the circumference of the stem base of the stem, and pressing the circumference of the stem base into the stem base receiving section. If the stem carrying head performs a rotational movement or a linear advancing/withdrawing movement while the stem is mounted therein, there is a risk that the stem may become dislodged from the stem carrying head or that the position thereof may become skewed. Therefore, by holding the circumference of the stem base of the stem between a pressing hook and a stem base receiving section, any dislodging or position deviation of the stem is prevented by mechanical means.
Moreover, desirably, the front end of a position registering hook which lifts upwards towards the stem base to be positioned in the heater section enters into a notch portion provided in the circumference of the stem base of the stem. By adopting a composition of this kind, it is possible to prevent rotating of the stem while it is being carried by the stem carrying head, and by this position registering operation, the stem can be fixed and prevented from deviating in position during the imaging and heating stages.
Desirably, the electronic component is a semiconductor laser crystal; a component mounting projection is formed in the stem base of the stem; and the component mounting face extends in a direction orthogonal to the stem base, in the component mounting projection. These can be regarded as optimum components for using in the die bonding device according to the present invention.
The die bonding device according to a further aspect of the present invention is a die bonding device for fixing an electronic component onto a component mounting face of a stem, characterized in that it comprises: heating means for bonding the electronic component with the component mounting face, by means of heating; imaging means for imaging the position of the component mounting face of the stem positioned in the heating means; locating means for locating the electronic component on the component mounting face of the stem positioned in the heating means, on the basis of the positional information for the component mounting face imaged by the imaging means; and moving means for moving the imaging means along the direction of the light axis of the imaging means, to a location where it does not impede to mount the electronic component onto the component mounting face.
Accordingly, in order to move the imaging means to a position where it does not impede the placement of the electronic component onto the component mounting face, the imaging means is moved along the direction of the light axis thereof. Consequently, when capturing an image of the component mounting face of the next stem, it is not necessary to realign the imaging means with the light axis thereof. Therefore, the mounting of electronic components onto stems can be automated readily.
REFERENCES:
patent: 4103814 (1978-08-01), Nishioka
patent: 4200393 (1980-04-01), Suzuki et al.
patent: 4799854 (1989-01-01), Niskala
patent: 4817849 (1989-04-01), Yamamoto et al.
patent: 5086559 (1992-02-01), Akatsuchi
patent: 514
Izumi Masanori
Kawashima Yoshiyuki
Nitta Hiroshi
Beyer Weaver & Thomas LLP
Dunn Tom
Nidec Tosok Corporation
Stoner Kiley
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