JP2003110183A - Bonding apparatus for semiconductor laser chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding apparatus which assembles a semiconductor laser more accurately and efficiently by shortening the time required for a welded part between a stem and a semiconductor laser chip to be cooled and solidified. SOLUTION: The bonding apparatus for a semiconductor laser chip is such that the stem 70 set on a heat plate 16 and the semiconductor chip 80 chucked and supported by a nozzle 41 are aligned with each other, and the stem 70 and the semiconductor laser chip 80 are heated and bonded to each other, with the semiconductor laser chip 80 pressed against the stem 70. Around the heat plate 16, a cooling gas emitting member 30 which emits a cooling gas toward the stem 70 and the semiconductor chip 80 after heating the stem 70 and the semiconductor chip 80 to a bonding temperature or above is connected to a cooling gas supply source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding apparatus for bonding a semiconductor laser chip to a stem, and more particularly to a semiconductor laser chip which enables efficient operation for bonding the semiconductor laser chip to the stem. Bonding apparatus

[0002]

2. Description of the Related Art A semiconductor laser is formed by mounting a semiconductor laser chip on a stem and is used in an optical disk pickup mechanism and optical information communication equipment. Among such semiconductor lasers, those used for optical information communication equipment require high accuracy in the direction of emission of the laser light from the semiconductor laser, and require a positional accuracy of about 10 μm when bonding the semiconductor laser chip to the stem. To be done. However, it is difficult to assemble a semiconductor laser with high precision, and the semiconductor laser used for these purposes has a low manufacturing yield and a high manufacturing cost.

In recent years, an automatic bonding apparatus for automatically bonding a semiconductor laser chip to a stem has been provided. In order to realize the assembly precision required for a semiconductor laser used in optical information communication equipment, the semiconductor laser chip is required. You must pay close attention to the assembly. For example, in Japanese Unexamined Patent Publication No. 5-355501, in consideration of individual differences in the optical axis of the semiconductor laser chip, when the semiconductor laser chip is mounted on the stem, the semiconductor laser chip is caused to emit light and the optical axis is detected to detect the semiconductor laser. A method of mounting and bonding a chip to a stem is disclosed.

[0004]

The method of bonding the semiconductor laser chip to the stem includes a method using solder and a method using a eutectic alloy of gold-silicon. When using solder, the solder pellet is placed on the stem, the semiconductor laser chip is roughly positioned and mounted thereon, and heated to about 220 ° C. to be joined. When using a gold-silicon eutectic alloy, the semiconductor laser chip is roughly positioned and mounted on the stem,
Heat to about ℃ and join.

In any case, in the bonding unit, the semiconductor laser chip and the stem are heated to a predetermined temperature, the semiconductor laser chip is positioned, and the semiconductor laser chip is cooled until the solder or gold-silicon eutectic alloy is cooled and solidified. While pressing with a pressing member. If the cooling and solidification time during bonding becomes long, the stem on which the semiconductor laser chip is mounted may thermally expand, which may cause the semiconductor laser chip to be displaced.Adjusting the optical axis of the semiconductor laser chip in advance Even if the mount position is set correctly by doing so, there is a problem that the optical axis may be displaced in the finished product.

As a method of solving this problem, an inert gas for cooling is introduced into the bonding unit, the semiconductor laser chip is bonded to the stem, and then the cooling gas is applied to the heater portion to cool the heater. The cooling time has been shortened by manufacturing it with a material having a small heat capacity. However, even by these methods, the cooling time cannot be sufficiently shortened, and the problem that the semiconductor laser chip is displaced on the stem due to thermal expansion of the stem or the supporting portion of the semiconductor laser still remains. ing.

Therefore, the present invention has been made to solve these problems, and an object of the present invention is, in a semiconductor laser chip bonding apparatus, a position where a semiconductor laser chip is accurately mounted on a stem,
To prevent the solder and gold-silicon eutectic alloy from shifting during cooling and solidification, shorten the time until the solder and gold-silicon eutectic alloy cools and solidifies, and with higher accuracy, and An object of the present invention is to provide a semiconductor laser chip bonding apparatus that enables efficient assembly of a semiconductor laser.

[0008]

In order to achieve the above object, the present invention has the following constitution. That is, the stem set on the heat plate and the semiconductor laser chip adsorbed and supported by the nozzle are aligned, and the stem and the semiconductor laser chip are heated while the semiconductor laser chip is pressed against the stem by the nozzle. In a bonding apparatus for a semiconductor laser chip to be joined together, after cooling the stem and the semiconductor laser chip around the heat plate to a joining temperature or higher, a cooling gas is radiated toward the stem and the semiconductor laser chip. The gas radiating member is provided so as to be connected to a supply source of the cooling gas. In addition, a channel that penetrates the heat plate and opens at a position where the stem is set in the heat plate is provided, and a channel that connects the channel and the suction and supply mechanism of the cooling gas is provided, and the heat plate is provided. When setting the stem, the stem is adsorbed and supported by a heat plate, and after the stem and the semiconductor laser chip are joined, suction and supply of the cooling gas to inject the cooling gas from the flow path. It is characterized in that a control unit for controlling the mechanism is provided. Further, an air blowing device is provided above the heat plate so as to blow air laterally to prevent fluctuation of the air due to hot air from the heat plate or the like.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a semiconductor laser chip bonding apparatus according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view showing the overall configuration of a semiconductor laser chip bonding apparatus. The semiconductor laser chip bonding apparatus of this embodiment is configured as a semi-automatic apparatus in which an operator performs a stem setting operation and a positioning operation when mounting the semiconductor laser chip on the stem.

In FIG. 1, reference numeral 10 denotes a main body of a semiconductor laser chip bonding apparatus. A bonding unit 20 for mounting a semiconductor laser chip on a stem is arranged on the right side of the front of the main body 10, and a semiconductor laser chip is mounted on the stem. The bonding section 40 is arranged on the front surface of the apparatus body 10, and the housing section 50 for housing the semiconductor laser chip is arranged on the left side of the front surface of the apparatus body 10. 60
Is a support table for supporting the bonding unit 20, and the bonding unit 20 is connected to the bonding section 40.
Is movably supported between the lower position and the retracted position on the right side of the apparatus body 10. Reference numeral 62 denotes a transport unit that moves the storage unit 50 between a position below the bonding unit 40 and a left retracted position of the apparatus body 10.

A nozzle 41 for adsorbing and supporting a semiconductor laser chip and necessary parts by air is arranged in the bonding section 40. The nozzle 41 is supported so as to be movable only in the vertical direction, and its moving position is controlled by the controller.
Reference numeral 42 is a camera for visually recognizing the joining position of the semiconductor laser chip and the stem for positioning the semiconductor laser chip with respect to the stem. In this embodiment, the camera 4
Two sets of two (one of which is not shown) are installed, and an image from the left and right direction of the semiconductor laser chip visually recognized by the two illustrated cameras 42, 42 is installed on the upper right portion of the front surface of the apparatus body 10. An image from the front direction of the stem, which is displayed on one of the monitors 43, 43 and visually recognized by one camera (not shown), is displayed on the monitor 43 installed in the upper left part of the main body 10. By disposing the semiconductor laser chip dedicated camera and the stem dedicated camera as described above, it is possible to focus the respective images firmly, which is preferable.

A characteristic component of the semiconductor laser chip bonding apparatus of this embodiment is the configuration of the bonding unit 20. The configuration of the bonding unit 20 will be described below. 2 is a top view of the bonding unit 20, and FIG. 3 is a sectional view showing the internal structure of the bonding unit 20. The bonding unit 20 is formed by fixing a cylindrical casing portion 22 to a base member 21, and a glass case 23 made of transparent glass is attached to an upper opening surface of the casing portion 22. In FIG. 2, reference numeral 23a is a see-through lid made of a glass plate or the like which is detachably attached to the glass case 23 inside the glass case 23. A setting hole 23b for setting a component such as a stem or a semiconductor laser chip at a bonding position is provided at the center of the see-through lid 23a.
Opens.

Reference numeral 24a denotes a connecting portion for introducing a cooling gas into the bonding unit 20, 24b denotes a connecting portion for introducing a heating gas into the bonding unit 20, and 24c adsorbs a stem in the bonding unit 20. It is a connection portion for sucking gas for supporting. Each of the connecting portions 24a, 24b, 24c is connected with a tube communicating with a gas supply mechanism for supplying a required gas. In this embodiment, nitrogen gas is used as the cooling gas and the heating gas. A gas suction and discharge mechanism is connected to the connecting portion 24c.

In FIG. 3, reference numeral 25 is a base block arranged inside the casing portion 22. A flow path 25a communicating with the connecting portion 24c is provided in the central portion of the base block 25. Reference numeral 26 is a heat plate fixed on the base block 25, and 27 is an attachment fixed on the heat plate 26. A flow path 27a communicating with the flow path 25a is provided at the center of the heat plate 26 and the attachment 27 so as to penetrate therethrough. In FIG. 3, the stem 70 is set on the attachment 27, and the semiconductor laser chip 80 is set on the stem 70.

Reference numeral 24d is a heating flow path communicating with the connecting portion 24b, and 24e is a cooling flow path communicating with the connecting portion 24a.
In FIG. 3, the heating flow path 24d and the cooling flow path 24e appear at overlapping positions, but they are completely formed inside the bonding unit 20 as separate flow paths. FIG. 4 shows the arrangement of the flow paths inside the bonding unit 20. In the embodiment, the cooling channels 24e are arranged on both sides of the heat plate for joining the semiconductor laser chip to the stem. Further, the cooling flow path 24e and the flow path 25a that communicates with the heat plate communicate with each other. From the heating flow path 24d communicating with the supply source of the heated gas, the heated gas is radiated toward the periphery of the part where the stem and the semiconductor laser chip are set.

In FIG. 3, reference numeral 30 is a cooling gas radiating member fixed on the block in which the heating flow path 24d is disposed. A radiation flow channel communicating with the cooling flow channel 24e is formed inside the cooling gas radiation member 30, and the cooling gas is radiated from this radiation flow channel toward the set position of the stem and the semiconductor laser chip. 5A and 5B are a perspective view and a sectional view of the cooling gas emitting member 30. The cooling gas emitting member 30 has a communication groove 3 inside a thick member formed in a semicircular ring shape.
0a is formed in an arc shape, and the communication groove 30 is formed by the thin plate material 31.
The opening of a is closed. 30b is a communication groove 30
It is a radiation port communicating with a and opening in a slit shape on the inner surface of the cooling gas radiation member 30. The communication groove 30a is connected to the cooling channel 24e, and the cooling gas is radiated from the radiation port 30b. In the present embodiment, the pair of cooling gas radiating members 30.
Was placed so as to sandwich the set position of the stem and the semiconductor laser chip, and cooling gas was emitted from the periphery of the stem and the semiconductor laser chip.

Next, a method of bonding the semiconductor laser chip to the stem using the semiconductor laser chip bonding apparatus of this embodiment will be described. The operator sits in front of the apparatus body 10 shown in FIG. 1 and sets the stem 70 on the heat plate 26 of the bonding unit 20 on the right side of the apparatus body 10. Stem 7
0 is pinched with tweezers, and the stem 70 is inserted into the bonding unit 20 through the set hole 23b opened in the center of the transparent lid 23a. At this time, a guide member may be used to align the stem 70.

A sensor detects that the stem 70 is set on the heat plate 26, or a switch operation is manually performed to operate a suction mechanism communicating with the flow path 25a, and the stem 70 is adsorbed and supported on the heat plate 26. . Next, the bonding unit 20 is supported by the support table 60, and is moved to a position below the bonding section 40 to mount the semiconductor laser chip on the stem 70. The bonding unit 2
The moving operation of 0 is performed automatically.

When the bonding unit 20 starts moving, the carrying section 62 operates and the storage section 50 moves to a position below the bonding section 40. Of course, the mutual movement is controlled by the control unit so that the bonding unit 20 and the storage unit 50 do not interfere with each other. Then the nozzle 4
1 descends to adsorb and support the semiconductor laser chip 80 from the storage section 50. In the operation of picking up the semiconductor laser chip 80 from the storage unit 50 to the nozzle 41, the storage unit 50 is moved in the XY direction with respect to the nozzle 41, and the semiconductor laser chip 80 is picked up from an appropriate position of the storage unit 50. be able to.

In the present embodiment, the stem 70 and the semiconductor laser chip 80 are joined with a gold-silicon eutectic alloy, but when joining with solder, the housing portion 5 is used.
The solder pellets may be stored in 0, the solder pellets may be picked up by the nozzle 41 and set on the stem 70, and then the semiconductor laser chip 80 may be placed on the solder pellets. As described above, in the apparatus of the present embodiment, appropriate components can be mounted and assembled.

After the semiconductor laser chip 80 is adsorbed and supported by the nozzle 41, the storage unit 50 is moved to the left retracted position, the bonding unit 20 is moved to the bonding operation position directly below the nozzle 41, and the nozzle 41 is moved. The semiconductor laser chip 80 is mounted on the stem 70 by descending. As described above, the operator checks the position of the semiconductor laser chip 80 on the stem 70 while referring to the image from the camera 42 on the monitor 43, and aligns the stem 70 and the semiconductor laser chip 80.
For example, an operation of aligning the end face of the semiconductor laser chip with the end face of the stem 70 is performed here.

The heat plate 26 is preheated with the stem 70 set. The camera 4
2 sees the mutual position of the stem 70 and the semiconductor laser chip 80 by seeing through the see-through lid 23a, but the heat of the heat plate 26 causes the hot air to rise from the set hole 23b of the see-through lid 23a, and the setting is performed. The air around the hole 23b fluctuates, which may disturb the image captured by the camera 42. In the apparatus of the present embodiment, in order to prevent the fluctuation of the air and ensure the visual recognition operation by the camera 42, as shown in FIG. 3, an air blowing device 32 is provided above the casing portion 22. ing.
The air blowing device 32 blows air in parallel with the upper surface of the see-through lid 23a to perform the operation of eliminating the fluctuation of the air. As shown in FIG. 2, the air blowing device 32 is formed in a semi-circular side surface shape according to the outer peripheral position of the transparent lid 23a, and is provided with a plurality of internal flow passages 32a in order to blow a parallel air flow. There is.

The positioning of the stem 70 and the semiconductor laser chip 80 is performed by finely moving the bonding unit 20 in the XY directions. When the stem 70 and the semiconductor laser chip 80 are aligned, the nozzle 41
While lightly pressing the semiconductor laser chip 80 from above, the heat plate 26 is further heated, and at the same time, the heating gas is fed into the bonding unit 20 from the heating gas source connected to the connecting portion 24b. The heating gas is stem 7.
0 and the semiconductor laser chip 80 are radiated, and the stem 70 and the semiconductor laser chip 80 are heated and become high in temperature.

Bonding with a gold-silicon eutectic alloy is 400
It is done at about ℃. The temperature is raised while detecting the internal temperature of the bonding unit 20 by the temperature sensor, and when the temperature reaches about 400 ° C., the temperature is maintained for a certain time, and then the cooling operation is performed. The heating operation and the cooling operation can be automatically switched by checking the temperature with a temperature sensor. The cooling operation is performed by first turning off the power supply to the heat plate 26 and feeding the cooling gas from the cooling gas supply source connected to the connecting portion 24a. The cooling gas passes through the cooling channel 24e and the cooling gas emitting member 30
Is radiated from the radiation port 30b toward the stem 70 and the semiconductor laser chip 80. By radiating the cooling gas from the cooling gas radiating member 30, the stem 70 and the semiconductor laser chip 80 can be cooled very efficiently, and can be rapidly cooled from the bonding temperature of 400 ° C. to the bonding temperature or lower. As a result, the stem 70 and the semiconductor laser chip 80 can be bonded in a short time.

When the cooling gas is radiated from the cooling gas radiating member 30 and the ambient temperature of the stem 70 and the semiconductor laser chip 80 becomes 400 ° C. or lower, the flow path 25a connected to the connecting portion 24c reverses the suction direction. The gas is released toward the stem 70. The gas sucked from the flow path 25a to support the stem 70 on the heat plate 16 is nitrogen gas, and in this embodiment, the stem 70 and the semiconductor laser chip 80 are discharged from the radiation port 30b of the cooling gas radiation member 30.
The gas radiating toward is actually the same gas.
When the gas is ejected instead of sucking the gas from the flow path 25a, the stem 70 is also cooled from the bottom surface thereof, and the stem 7
0 and the semiconductor laser chip 80 are cooled from the entire outer peripheral surface.

FIG. 6A shows a state in which the stem 70 is adsorbed and supported by the heat plate 26 and the attachment 27, and FIG. 6B shows a state in which gas is ejected from the flow path 27a. As shown in FIG. 6 (b), by ejecting gas from the flow path 27 a, a gas flow path is formed between the attachment 27 and the bottom surface of the stem 70 so that the stem 70 floats slightly from the attachment 27. become. The nozzle 41 presses the semiconductor laser chip 80 from above to prevent the semiconductor laser chip 80 from being displaced until the gold-silicon eutectic alloy is joined, but the ambient temperature between the stem 70 and the semiconductor laser chip 80 is As long as the temperature is lowered to 400 ° C. or lower, the semiconductor laser chip 80 will not be displaced even if the gas is ejected from the flow path 27a.

In the semiconductor laser chip bonding apparatus of this embodiment, the semiconductor laser chip 80 is bonded to the stem 70 by cooling from the lower surface of the stem 70 as described above, and then the joint portion is effectively cooled. The bonding position of the semiconductor laser chip 80 with respect to the stem 70 does not shift due to the time required for cooling, and cooling is performed efficiently. It is possible to shorten the time from the removal to the removal, shorten the bonding operation time between the stem 70 and the semiconductor laser chip 80, and improve the productivity of the device.

In the above embodiment, an example in which the stem 70 and the semiconductor laser chip 80 are bonded with a gold-silicon eutectic alloy has been described, but the same applies to the case of bonding with solder, in the cooling operation. By ejecting the cooling gas from the heat plate 26 to the stem 70, the semiconductor laser chip 80 can be bonded to the stem 70 with high accuracy, and the bonding work can be made efficient. In the case of bonding with solder, the heating temperature is 2
Since the temperature may be about 20 ° C., the cooling time is further shortened.
Further, by using a heater having a small heat capacity such as a ceramic heater for the heat plate 26, the cooling time can be further shortened.

[0029]

According to the semiconductor laser chip bonding apparatus of the present invention, after the semiconductor laser chip is bonded to the stem, the cooling gas radiating member for radiating the cooling gas toward the stem and the semiconductor laser chip is provided. This makes it possible to efficiently cool the joint between the stem and the semiconductor laser chip, prevent displacement of the bonding portion between the stem and the semiconductor laser chip, and perform a highly accurate bonding operation. Moreover, since the cooling time can be shortened, the bonding operation can be efficiently performed. In addition, by ejecting a cooling gas from the heat plate toward the stem during the cooling operation, it is possible to more efficiently cool the bonding portion between the stem and the semiconductor laser chip, and to perform a more accurate and efficient bonding operation. It has a remarkable effect that it can be performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a semiconductor laser chip bonding apparatus according to the present invention.

FIG. 2 is a plan view of a bonding unit.

FIG. 3 is a cross-sectional view showing an internal structure of a bonding unit.

FIG. 4 is an explanatory diagram showing an arrangement of flow paths inside a bonding unit.

FIG. 5 is an explanatory diagram showing a configuration of a cooling gas emitting member.

FIG. 6 is an explanatory diagram showing a state in which a semiconductor laser chip is bonded to a stem.

[Explanation of symbols]

10 Device body 16 heat plate 20 Bonding unit 21 Base member 22 Casing part 23 glass cases 23a see-through lid 23b set hole 24a, 24b, 24c connection part 24d heating channel 24e Cooling channel 25 base blocks 25a channel 26 heat plate 27 Attachment 27a channel 30 Cooling gas radiating member 30a communication groove 30b radiation port 31 thin plate material 32 Air blowing device 40 Bonding part 41 nozzles 42 camera 43 monitors 50 storage 60 support table 62 Transport section 70 stem 80 Semiconductor laser chip

Claims (3)

[Claims] 1. A stem set on a heat plate and a semiconductor laser chip supported by being adsorbed by a nozzle are aligned, and the stem and the semiconductor laser chip are pressed while the semiconductor laser chip is pressed against the stem by the nozzle. In a semiconductor laser chip bonding apparatus for heating and bonding with each other, around the heat plate, after heating the stem and the semiconductor laser chip to a bonding temperature or higher, a cooling gas is directed toward the stem and the semiconductor laser chip. A bonding device for a semiconductor laser chip, characterized in that a radiating cooling gas radiating member is connected to a cooling gas supply source. 2. A flow path that penetrates through the heat plate and opens at a position where a stem is set on the heat plate, and a flow path that connects the flow path and a cooling gas suction / supply mechanism is provided. When setting the stem on the heat plate, the stem is adsorbed and supported by the heat plate, and after the stem and the semiconductor laser chip are bonded, the cooling gas of the cooling gas is sprayed from the flow path. 2. The semiconductor laser chip bonding apparatus according to claim 1, further comprising a control unit that controls the suction and supply mechanism. 3. An air blowing device for blowing air in the lateral direction above the heat plate to prevent fluctuations of the air due to hot air in the heat plate or the like. Semiconductor laser chip bonding equipment.