JPH06232507A - Semiconductor laser chip bonding orientation adjusting device and automatic die-bonding device - Google Patents

Abstract

PURPOSE:To stabilize the optical axis of a laser beam, and to enhance the yield of products by shifting a semiconductor laser chip for correction of the deviation amount with respect to the reference axis of the position of light emission and the angle of irradiation. CONSTITUTION:The laser beam of a semiconductor laser chip 1 is projected on a screen 3, it is converted into an image signal by an image-input part 4 and sent to an image processing part 6. Also, the image in front of the semiconductor laser chip 1 is inputted by a CCD camera 5, and its image signal is also sent to the image processing part 6. By measuring the center of distribution of laser beam from the image sent from an image input part 4 and also by measuring the position of the point of emitted light from the image sent from the CCD camera using the image processing part 6, the position of light-emitted point and the angle of irradiation are detected. A control part 7 gives an instruction to a semiconductor laser adjusting stage 8 pertaining to the amount of deviation from the reference position of light- emitting part and irradiation angle which were set in advance. Based on the instruction, the irradiation angle is adjusted by the control part 7 using the light emitting point as the reference position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser chip bonding orientation adjusting device and an automatic die bonding device. More particularly, it relates to a semiconductor laser chip bonding orientation adjusting device and an automatic die bonding device for adjusting the orientation and attitude of a semiconductor laser chip die-bonded by a die bonding device in a semiconductor laser assembly process, for example.

[0002]

2. Description of the Related Art In recent years, semiconductor lasers have a structure in which a semiconductor laser chip is fixed on a stem and are used in various fields such as compact discs and optical information processing equipment. Has become. In addition, the production of automatic die bonding apparatuses for die bonding such semiconductor laser chips is increasing.

The automatic die bonding apparatus is required to position the semiconductor laser chip with respect to the stem with high accuracy and also to mount the semiconductor laser chip on the stem with high accuracy. That is, generally, the semiconductor laser chip is attached to the center of the outer shape of the stem, but there is a disadvantage that the central axis is displaced due to thermal expansion of the stem during bonding of the semiconductor laser chip. In order to solve such inconvenience, for example, in JP-A-62-58645, a mounting reference surface is provided on the heating body on which the stem is mounted, and the mounting reference surface of the stem is brought into contact with the mounting reference surface. A die bonding apparatus is disclosed which is configured to prevent positional deviation by placing it. In addition, since the position of the semiconductor laser chip cannot be corrected after being fixed to the stem, another device (bonding azimuth adjusting device) installed in parallel with the stem is used to adjust and adjust the azimuth and attitude of the semiconductor laser chip. There is also used a method in which the semiconductor laser chip is moved to a position right above the stem with a movement accuracy of about 1 μm, and the semiconductor laser chip is attached to the stem and fixed by heating. As such a bonding azimuth adjusting device,
An example is a device including two parallel positioning pins provided on the upper surface of the table, another positioning pin orthogonal to these two positioning pins, and a suction nozzle for suctioning the semiconductor laser chip. In this device, a semiconductor laser chip in the shape of a rectangular parallelepiped, which is adsorbed by an adsorbing nozzle, is brought closer while sliding, and two orthogonal surfaces are brought into contact with each other to adjust the azimuth and orientation of the semiconductor laser chip. However, the operation of this bonding azimuth adjusting device requires skill and it is difficult to adjust the semiconductor laser chip.

As a device that facilitates the above operation,
An apparatus has been proposed in which a CCD camera is installed above a moving table and a semiconductor laser chip mounted on the table. This device calculates the amount of displacement of placement by collating the reference image information with the image information of the entire outer shape of the semiconductor laser chip captured by the CCD camera in advance,
It was adjusted by moving the table so that this gap would disappear.

However, the above-described bonding azimuth adjusting device adjusts the azimuth and orientation only by the outer shape of the semiconductor laser chip, and does not consider the irradiation direction of the laser light emitted from the light emitting surface of the semiconductor laser chip. The laser light emitted from the light emitting surface of the semiconductor laser chip is not all emitted at a constant angle with respect to the light emitting surface, and therefore varies from product to product. Therefore, there is a problem that the optical axis of the laser light emitted from the semiconductor laser is not stable even if the positioning of bonding is performed based on the outer shape of the semiconductor laser chip and the yield of products is deteriorated.

In order to solve this problem, Japanese Patent Laid-Open No. 2-
In the 114590 publication, a light receiving element for receiving the light flux emitted from the semiconductor laser chip and converting it into image information,
A bonding azimuth adjusting device is disclosed which includes a calculating unit for calculating a pixel at the center of a light beam from image information and a stage rotating unit for making a distance from a central value of a reference light beam zero. .

This device is adjusted by using a device for positioning with only the above shape, and further, in the above device, a light beam emitted from a semiconductor laser chip is received by a light receiving element, and this light receiving element converts the image information into image information. The pixel of the center of the light flux is converted and calculated from the image information, and the value of the center pixel of the reference light flux is stored in advance in order to be compared with this image information, and the calculated center value of the light flux and the reference light flux are stored. The distance between the centers is calculated by comparing with the center value of, and the stage is rotated and adjusted so that the calculated distance becomes zero.

However, in the above apparatus, for example, even when the semiconductor laser chip is irradiated from an oblique direction, the position of the pixel at the center of the light beam calculated from the image information of the irradiated light beam and the pixel at the center of the light beam serving as the reference are detected. If the positions coincide with each other, it is determined that the adjustment has been made, and the problem that the optical axis of the laser beam is not stable and the yield of the product is deteriorated has not been solved.

The inventors of the present invention have found that the above problems can be solved by installing a means for adjusting the azimuth and orientation of the light emitting point of the semiconductor laser chip in the bonding azimuth adjusting device, and arrived at the present invention.

[0010]

Thus, according to the present invention, there is provided a semiconductor laser chip bonding azimuth adjusting device for setting a semiconductor laser chip in a predetermined azimuth, wherein laser light is emitted from the semiconductor laser chip. Power source means for emitting light, screen means for projecting the laser light, image input means for inputting an image projected on the screen means, and the center of distribution of the laser light is measured from the image input by the image input means. An image processing means for calculating the light emitting point position and the irradiation angle, and a correction means for moving the semiconductor laser chip to correct the deviation amount of the light emitting point position and the irradiation angle with respect to the reference axis. Provided is a semiconductor laser chip bonding direction adjusting device.

As the power supply means for emitting laser light from the semiconductor laser chip, known means can be used, for example, a constant current power supply or the like can be used. As the screen means, for example, a diffusion plate can be used. Examples of the image input device include a CCD camera and a photodiode. Examples of the image processing means include processing means such as analog processing, digital processing and hybrid processing, but digital processing means is preferable. As the correcting means, a known method can be used, and for example, the position can be adjusted by providing a moving means on the stage on which the semiconductor laser chip is mounted or adsorbing by a suction nozzle.

In the semiconductor laser chip bonding azimuth adjusting device of the present invention, the following constituent means may be mentioned as constituent means for detecting the light emitting point position and the irradiation angle. First, the provision of screen moving means can be mentioned. That is, since the distribution of the laser light can be measured at two points by moving the screen means, the light emitting point position and the irradiation angle can be calculated by processing the measurement result by the image processing means. The deviation amount can be calculated by comparing the calculated value with a reference value which is measured in advance. By correcting this deviation amount, a correct irradiation angle can be obtained.

As still another constituent means, a first image processing means for inputting an image projected on the screen means and a second image processing means for inputting an image on the light emitting surface of the semiconductor laser chip.
The image processing means may be provided. That is, the first
The center of the distribution of the laser light is measured from the image input by the image processing means, and the light emitting point position is measured from the image input by the second image processing means, the irradiation angle is calculated by the image processing means, and the measured light emitting point position is measured. By correcting the deviation amount of the irradiation angle with respect to the reference axis, the correct irradiation angle can be obtained.

Further, by combining the semiconductor laser chip bonding azimuth adjusting device and the automatic bonding device, a more accurate automatic bonding device can be obtained.

A known device can be used as the automatic bonding device. For example, the automatic bonding apparatus comprises a mounting means having a heating function for mounting and bonding the stem, and a moving means having a collet for supplying the semiconductor laser chip onto the stem. The moving means having the collet is adapted to be able to suck and move the semiconductor laser chip by connecting to a vacuum pump or the like. Examples of the material of the stem used include mild steel. As the mounting means for mounting the stem, a mounting means made of metal having a small coefficient of thermal expansion can be preferably used, and for example, stainless steel can be used. This placing means has a heating function capable of heating using, for example, a heater.

Further, in the present invention, as a means for setting the semiconductor laser chip on the stem, a mounting means or a moving means is used to bring the semiconductor laser chip into a temporary correction state,
It is also possible to provide an automatic die-bonding apparatus which later makes fine adjustments using the above-mentioned bonding azimuth adjusting apparatus. As the device used for this temporary placement method, a known device can be used, but a measuring device for measuring the shape of the stem in the placing device or the moving device, and a reference axis by calculating the central axis of the stem. It is preferable to provide a provisional correction unit that determines the amount of deviation between and and temporarily corrects the position according to the amount of deviation.
As the temporary correction means, it is possible to move the mounting means for mounting the stem by the amount of deviation or move the moving means having a collet by the amount of deviation.

It is also possible to directly mount the semiconductor laser chip on the stem without adjusting the provisional correction means, adjust the bonding direction using the bonding direction adjusting apparatus of the present invention, and perform fusion bonding. Further, it is possible to directly mount the semiconductor laser chip, which has been adjusted by using the bonding direction adjusting device, directly on the stem.

[0018]

EXAMPLE 1 A more detailed description will be given with reference to FIG. 1, which is an example of a semiconductor laser chip bonding orientation adjusting apparatus according to the present invention. The bonding azimuth adjusting device of FIG. 1 includes a power source unit 2 (power source unit) for emitting light from the semiconductor laser chip 1, a screen 3 (screen unit), an image input unit 4 (first image input unit), and a CCD camera 5 (second unit). Image input means),
The image processing unit 6 (image processing unit), the control unit 7, and the correction unit including the semiconductor laser adjusting stage 8 are included.

First, the semiconductor laser chip 1 emits laser light by connecting to the power supply section 2. This laser light is projected on the screen 3, converted into a video signal by the image input unit 4, and sent to the image processing unit 6. Also C
The CD camera 5 inputs an image on the front surface of the semiconductor laser chip, and the input video signal is also sent to the image processing unit 6. The image processing unit 6 determines the center of the distribution of the laser light from the image sent from the image input unit 4, and the CCD camera 5
The position of the light emitting point and the irradiation angle are detected by measuring the position of the light emitting point from the image sent from. The control unit 7 commands the semiconductor laser adjusting stage 8 to move a distance enough to correct the amount of deviation of the preset emission point / irradiation angle from the reference position. Based on this command, the semiconductor laser adjusting stage 8 moves the semiconductor laser chip so that the optical axis of the laser light is parallel to the z axis with the light emitting point position as the reference position, and adjusts the irradiation angle.

Embodiment 2 Further, a semiconductor laser chip bonding direction adjusting apparatus according to an embodiment of the present invention will be described in more detail with reference to FIG. The bonding azimuth adjusting device of FIG. 2 has a power source unit 2 (power source unit) for emitting light from the semiconductor laser chip 1, a screen 3 (screen unit), a screen moving stage 25 (screen moving unit), and an image input unit 4 (image input unit). Image processing unit 6 (image processing means) and control unit 7
And a correction means including a semiconductor laser adjusting stage 8.

First, the semiconductor laser chip 1 emits laser light by being connected to the power supply section 2. This laser light is projected on the screen 3, converted into a video signal by the image input unit 4, and sent to the image processing unit 6. Next, the screen 3 is moved in the z-axis direction by the screen moving stage 5, and the laser light projected on the screen 3 again is converted into a video signal by the image input unit 4 and sent to the image processing unit 6. The image processing unit 6 measures the center of the distribution of the laser light at the two positions sent from the image input unit 4, and detects the light emitting point position and the irradiation angle. The control unit 7 commands the semiconductor laser adjusting stage 8 to move a distance enough to correct the amount of deviation of the preset emission point / irradiation angle from the reference position. Based on this command, the semiconductor laser adjusting stage 8 sets the light emitting point position as a reference position,
The irradiation angle is adjusted by moving the semiconductor laser chip so that the optical axis of the laser light is parallel to the z axis.

FIG. 3 shows the light emitting point position of the semiconductor laser chip and the principle of detecting the irradiation angle in the above adjusting method.
As shown above, move screen 3 to move L1,
Laser light is projected at two points L2, and the distribution center of each laser light projected by the image processing unit 6 is calculated (indicated as a + mark in an ellipse in FIG. 3). As a result, it is clear that the light emitting point of the semiconductor laser chip 1 exists on the straight line connecting the distribution centers of L1 and L2. Therefore, the angle between the straight line connecting the distribution centers of the two points and the straight line parallel to the reference axis passing through the light emitting point is detected as the irradiation angle of the semiconductor laser chip.

Embodiment 3 Next, an automatic die bonding apparatus using the bonding azimuth adjusting apparatus of the present invention will be described with reference to FIGS. FIG. 4 is a system configuration diagram of the automatic die bonding apparatus. First, the measuring means of the stem comprises a sensor and a measuring unit. The shape is measured by using the sensor, and the result is input to the measuring unit.

Further, the temporary correction means for temporarily correcting the amount of deviation is composed of an arithmetic unit, a control unit, an adjusting mechanism on which the stem is mounted, and a transport mechanism having a collet for sucking the semiconductor laser chip. The measurement result is compared with pre-input reference data by the calculation unit to calculate the amount of deviation (the calculation unit may be a computer, a circuit using an operational amplifier, or the like). This deviation amount is input to the control unit, and the semiconductor laser chip is tentatively corrected by moving the adjusting mechanism or the transport mechanism having the collet that adsorbs the semiconductor laser chip until the deviation becomes zero.

FIG. 5 shows a front view of the essential parts of the automatic die bonding apparatus. In this automatic die bonding apparatus, reference numeral 11 in the drawing is a vertically movable stage installed in a transfer mechanism, and a collet 12 is attached to the tip of this stage 11. A vacuum pump (not shown) or the like is connected to the collet 12, and the semiconductor laser chip 13 is vacuumed and sucked at the tip thereof and supplied to the stem 14. In the figure, reference numeral 15 is a stem mounting table, 15a is a fixed type, and 15b and 15c are movable up and down and left and right respectively by using an air cylinder or the like using compressed air,
As shown in FIG. 5, it can be fixed by applying a constant pressure on the mounted stem 14. 15c
Is provided with a measurement reference surface 15ca, and a laser displacement meter 16 for measuring the distance to the reference surface is installed at a position parallel to the movable direction of the mounting table 15c. In addition, the stem mounting table 15 is installed in an adjusting mechanism that can be moved left and right. Further, the stem mounting table 15 is made of stainless steel which is a metal having a small thermal expansion coefficient,
The influence of heat is relatively small. Further, the bonding direction adjusting device can be installed at any position of the automatic die bonding device.

Next, the method of operating the automatic die bonding apparatus of the present invention will be described with reference to FIG. First, the mounting table position is predetermined when the stem is mounted. Stem 14
One is for the fixed mounting table 15a and the other is for the movable mounting table 1
It is pressed and fixed by 5b and 15c. Then, the distance to the measurement reference plane 5ca is measured by the laser displacement meter 1
6 is measured as measurement data. The measurement data is input to the calculation unit. By comparing with the measurement data of the reference stem determined in advance here, x of the stem 14 is compared.
The amount of deviation between the central axis in the direction and the reference axis is calculated. This deviation amount is input to the control unit, and the stem adjusting mechanism is moved until the deviation amount becomes zero. Next, collet 12
Is lowered, and the semiconductor laser chip is tentatively corrected.

Next, the temporarily corrected corrected irradiation angle of the semiconductor laser chip 13 is adjusted using the bonding direction adjusting device of the second or third embodiment. Further, by heating the mounting table, the adjusted semiconductor laser chip 13 is die-bonded to obtain a semiconductor laser.

[0028]

By using the semiconductor laser chip bonding azimuth adjusting device and the automatic bonding device of the present invention, both the light emitting point position and the irradiation angle can be detected, so that both the light emitting point position and the irradiation angle are adjusted. As a result, the irradiation angle can be adjusted more accurately than before, and the yield of semiconductor laser chips is also improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a semiconductor laser chip bonding orientation adjusting device of the present invention.

FIG. 2 is a schematic diagram of a semiconductor laser chip bonding orientation adjusting device of the present invention.

FIG. 3 is a schematic diagram showing the principle of detection of a light emitting point position and an irradiation angle of the bonding azimuth adjusting device of FIG.

FIG. 4 is a system configuration diagram of a main part of the automatic bonding apparatus of the present invention.

FIG. 5 is a front view of the essential parts of the automatic bonding apparatus of the present invention.

FIG. 6 is a diagram showing a method of adjusting the automatic bonding apparatus of FIG. 5 step by step.

[Explanation of symbols]

 1 semiconductor laser chip 2 power supply part 3 screen 4 image input part 5 CCD camera 6 image processing part 7 control part 8 semiconductor laser adjusting stage 11 stage 12 collet 13 semiconductor laser chip 14 stem 15 stem mounting table 15a fixed mounting table 15b movable system Mounting table 15c Movable mounting table 15ca Measurement reference plane 16 Laser displacement meter 25 Screen moving stage

Claims (6)

[Claims] 1. A semiconductor laser chip bonding azimuth adjusting device for setting a semiconductor laser chip in a predetermined azimuth, wherein a power source means for emitting laser light from the semiconductor laser chip and a screen for projecting the laser light. Means, an image input means for inputting an image projected on the screen means, and an image for measuring the center of distribution of the laser light from the image input by the image input means and calculating the light emitting point position and the irradiation angle. A bonding direction adjusting device for a semiconductor laser chip, comprising: a processing means; and a correction means for moving the semiconductor laser chip in order to correct a deviation amount of a light emitting point position and an irradiation angle with respect to a reference axis. 2. The image input means comprises a first image input means for inputting an image projected on a screen means and a second image input means for inputting an image of a light emitting surface of a semiconductor laser chip, and image processing. A means for measuring the distribution center of the laser light from the image input by the first image input means and a light emitting point position from the image input by the second image input means, and calculating an irradiation angle. Item 1. A semiconductor laser chip bonding direction adjusting device according to Item 1. 3. The semiconductor laser chip bonding azimuth adjusting device according to claim 1, wherein the screen means comprises a screen moving means. 4. A semiconductor laser chip bonding orientation adjusting device according to claim 1, a stem mounting means having a heating function for mounting and bonding a stem, and a semiconductor laser chip is supplied onto the stem. An automatic die bonding apparatus comprising a moving means having a collet. 5. The moving means obtains a deviation amount between a measuring means for measuring the shape of the stem and a reference axis preliminarily measured by calculating a central axis of the stem, and the position is temporarily changed according to the deviation amount. The automatic die bonding apparatus according to claim 4, further comprising provisional correcting means for correcting. 6. The mounting means obtains a deviation amount between a measuring means for measuring the shape of the stem and a reference axis preliminarily measured by calculating a central axis of the stem, and determines a position according to the deviation amount. The automatic die bonding apparatus according to claim 4, further comprising provisional correction means for temporarily correcting.