KR100402591B1 - Machine and method to bond laser diode - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding apparatus and method for a laser diode (hereinafter referred to as "LD"), comprising: a stem carrying mega unit; Conveyor unit; Stem export mega part; Heater unit; Stem supply extraction part; A submount chip supply unit; LD chip supply unit; An image processing unit: a submount bonding head portion; In a conventional laser diode bonding apparatus comprising an LD junction head portion, etc., located between an LD chip upper camera and an LD chip lower camera of the image processing unit to find a light emitting point to align the LD chip on the stem. Comprising a light emitting point detection unit for providing a device, and matching the light emitting point of the LD chip and the center line of the stem, and bonding the LD chip to the stem to provide an apparatus and method for bonding a laser diode to improve the degree of bonding. It is.

Description

Bonding device and method of laser diode {MACHINE AND METHOD TO BOND LASER DIODE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding apparatus and method for a laser diode (hereinafter referred to as " LD "). The present invention relates to a laser diode bonding apparatus and method for recognizing a light emitting point emitting light by emitting the LD chip through an image processing unit and bonding the LD chip to a stem around the light emitting point to improve the degree of bonding.

In general, the stem is a component for bonding and using an LD chip used as a light source such as a laser beam printer, a compact disk player, and optical communication, and as shown in FIG. The protruding header 54, the submount chip 101 attached to the header 54, and the LD chip 201 are attached to the submount chip 101 to form a stack, and the stem 10 is formed. A plurality of connection pins for grounding the cover, attached to an upper surface of the stem 10 to cover an MPD (Monitor Photo Diode) 11, which is a light receiving element for monitoring the light output of the LD, and an upper portion of the stem 10. The main consists of a stem package including a cap (12).

The process to make the stem package is as follows. Attaching the MPD to a groove formed in an upper surface of the stem, attaching a wire to allow electricity to flow between the MPD and the stem, attaching a submount chip on the header, and on the submount chip. Attaching an LD chip, attaching a wire so that electricity flows between the LD chip and the stem, sealing with the cap to protect all the bonded devices, and applying the current to the stem for a long time in a high temperature chamber. The stem package is completed through the step of filtering the vulnerable stem package by applying to the package and the inspection step of filtering the stem package according to the specification through electrical and optical measurements on the remaining stem package in the step.

As described above, the conventional laser diode bonding apparatus for joining the submount chip and the LD chip to the header of the stem includes a stem carrying mega-unit in which a stem is loaded; A conveyor unit for transferring the stem; A stem carrying mega part for collecting the joined stem; A heater unit for joining the stem; A stem supply extracting part supplying the stem to the heater part; A submount chip supply unit for transferring the divided submount chips; LD chip supply unit for transferring the divided LD chip; An image processing unit for aligning the divided chips, comprising: a submount bonding head unit for collecting the submount chips; And an LD junction head portion for picking up the LD chip, and the LD chip upper camera and the LD chip lower portion in a path through which the LD chip and the submount chip are transported to attach the LD chip and the submount chip. A submount chip upper camera and a submount chip lower camera for aligning the camera and the submount chip are installed to read an image projected from the image processing unit, and then the LD chip and the submount chip are placed on the header. Bonding was performed. In more detail, when the LD chip or the submount chip is positioned on the LD chip lower camera or the submount chip lower camera, the LD chip or the submount chip is a reflector so that it appears white by reflecting light. The part is dark and visible to the image processing apparatus because it cannot reflect light. The upper surface of the LD chip or the submount chip, which is illuminated in this manner, is aligned to coincide with the virtual horizontal vertical line of the image processing apparatus, and the LD chip or the submount chip thus aligned is an LD junction head part or a submount junction head It is picked up and bonded to match the center line on the top line outer center line of the LD chip with the center line of the header.

As described above, in the case where the LD chip or the submount chip is uniformly bonded to the header, there is no problem when the submount chip is bonded. As a result of errors caused by scribing and breaking, the light emitting point of the LD chip is not located at the center of the outside. Therefore, when the light emitting point 301 is not positioned at the center of the LD chip 101 as shown in FIG. 6B, the lens is formed through the lens formed on the upper end of the cap 12 which is covered by the last process of the stem package. The incident laser beam 300 is not only incident off the center, but also does not enter 100% into the core of the optical fiber located on the top of the cap 12, so that the optical transmission speed is lowered and the noise is increased. It becomes impossible stem package.

The present invention was devised to solve the above problems, and an object of the present invention is to improve the existing method of recognizing and bonding the outer edge of the LD chip to actually emit light of the LD chip during the process of partitioning the LD wafer. The light emitting point of the LD chip determined by scribing and breaking is found and accurately positioned at the center line of the header of the stem, and a 100% laser beam is incident on the optical fiber located on the top of the cap. It is to provide an apparatus and method for finding a light emitting point of the LD by having a separate light emitting point detector in the laser diode junction.

1 is a perspective view of a stem package equipped with a laser diode,

2 is a perspective view of a state in which the stem is mounted on the heater unit,

3 is a perspective view of a divided wafer,

4 is a schematic diagram of a bonding apparatus of a laser diode according to the present invention;

5 is a configuration diagram of a light emitting point detector of a laser diode chip;

6A is a state diagram in which a laser diode chip is bonded based on a light emitting point according to the present invention;

6B is a state diagram in which a laser diode chip is bonded on the basis of a conventional outline;

7 is a flowchart illustrating a method of bonding a laser diode and a submount chip.

* Description of the symbols for the main parts of the drawings *

1: Stem carrying mega part 2: Conveyor part

3: Stem delivery mega part 4: Stem supply extraction part

5: heater part 6: light emitting point detector

10: Stem 11: MPD

12: Cap 50: Heater Block

51: lower positioning pin 52: rear support pin

53: upper support pin 54: header

60: power jig unit 61: light emitting point recognition camera

62: upper surface of power jig 63: positive probe pin

64: negative probe pin 65: image processing apparatus

70: submount chip supply unit 71: submount chip upper camera

72: submount bonding head portion 73: collet

74: submount chip lower camera 80: LD chip supply

81: LD chip upper part camera 82: LD junction head part

83: collet 84: LD chip lower camera

90: joining head transfer unit 100: submount wafer

101: submount chip 200: LD wafer

201: LD chip 300: laser beam

301 light emitting point

In order to achieve the above object, the present invention is a stem-loaded carry-in mega unit; A conveyor unit for transferring the stem; A stem carrying mega part for collecting the joined stem; A heater unit for joining the stem; A stem supply extracting part supplying the stem to the heater part; A submount chip supply unit for transferring the divided submount chips; LD chip supply unit for transferring the divided LD chip; An image processing unit for aligning the divided chips; A submount junction head unit for picking up the submount chip; In a conventional laser diode bonding apparatus including an LD junction head portion for picking up the LD chip, the image processing unit includes an LD chip upper camera, an LD chip lower camera, and the submount for aligning the LD chip. It consists of a submount chip upper camera and a submount chip lower camera to align the chip, and located between the LD chip upper camera and the LD chip lower camera to find the light emitting point to align the LD chip on the stem. It is a junction device of a laser diode comprising a light emitting point detector.

The light emitting point detector may include: a power jig unit for placing the LD chip on an upper surface thereof; Plus and minus probe pins for applying power to the LD chip; A light emitting point recognition camera for image processing a laser beam generated from the LD chip; And an image processing apparatus for displaying the shadows projected on the light emitting point recognition camera, wherein the power jig portion is coated with a conductive material on an upper surface thereof to conduct electricity to the LD chip located on the upper surface.

The method of bonding the LD chip to the stem using the laser diode bonding apparatus includes supplying the stem to the heater through the stem carrying mega part, the conveyor part, and the stem supply extracting part; Aligning the submount chip supplied from the submount chip supply unit with the image processing unit; Positioning the submount chip in the stem using the submount junction head portion; Arranging the LD chip supplied from the LD chip supply unit to the image processing unit; Finding the light emitting point of the LD chip by passing the aligned LD chip through the light emitting point detector; Finally aligning the LD chip with respect to the light emitting point of the LD chip; Transferring the LD chip to the stem using the LD junction head portion; Bonding the submount chip to the stem; Correcting the position of the LD chip and positioning the LD chip in the stem; Bonding the LD chip to the stem; And taking out the stem to which the submount chip and the LD chip are joined.

The LD chip position correction method may further include calculating an eccentric distance by calculating a displacement between a position of a laser beam projected through a light emitting point recognition camera and a center point of the light emitting point recognition camera; Finding a light emitting point of the LD chip based on the eccentric distance; And determining how far from the outline of the LD chip with respect to the light emitting point, and correcting by matching the light emitting point to the center of the stem.

An embodiment according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a perspective view of a state in which a stem is mounted on a heater unit, and the LD chip 201 and the submount chip 101 are mounted on the header 54 of the stem 10 as shown in FIG. 1. The stem 10 is inserted into and fixed to a fixing groove formed in the heater block 50 so as to be bonded by the high temperature heat conducted from the heater formed at the side of the heater block 50, and the rear surface of the stem 10 is fixed. In order to support the rear support pin 52 is supported, the upper side of the outer peripheral surface of the stem 10 is fixed by the upper support pin 53, the lower side of the stem 10 to the lower positioning pin 51 The stem 10 is firmly fixed by pressing.

FIG. 3 is a perspective view of a divided wafer, and a state in which the LD wafer 200 or the submount wafer 100 generated through the semiconductor wafer process is divided by using a scribing and breaking method and separated and used one by one. FIG. It is shown. The divided wafers 100 and 200 were attached onto a slightly sticky blue tape so that only one was separated so that the divided chips did not scatter. The wafer 100 and 200 are divided by scribing and breaking by breaking. First, the scribing method uses a diamond tip having a hardness to move the diamond tip to the left and right to draw gold on the LD wafer 200 or the submount wafer 100, After the pitch is moved, the scribing is continued to draw gold on the entire LD wafer 200 or the submount wafer 100. The purpose of the scribing is to cut the LD wafer 200 directly with the diamond tip to damage the LD chip 201, and the LD wafer 200 has a crystal structure of a compound semiconductor GaAs substrate. Since it has a characteristic that only gold is applied and the impact is cut in one direction, it is usually not suitable for the method of generating the LD chip 201 one by one, so the scribing is performed. Next, the method of performing the braking is to place the blade-shaped blade (blade) up and down in the scribed LD wafer 200 or the submount wafer 100 to move it up and down at the same time to the LD wafer ( 200 or the submount wafer 100 is split so that the LD chip 201 or the submount chip 101 are divided one by one. The divided LD chip 201 or the submount chip 101 is absorbed and transferred by the LD junction head 82 or the submount junction head 72, and the header of the stem 10 may be transferred. 54) and bonding is performed.

4 is a schematic view of a laser diode bonding device according to the present invention, wherein the laser diode bonding device includes: a stem carrying mega unit 1 on which the stem 10 is loaded; A conveyor unit 2 for conveying the stem 10; A stem carrying mega part (3) for collecting the joined stem (10); A heater unit 5 for joining the stem 10; A stem supply extracting part 4 for supplying the stem 10 to the heater part 5; A submount chip supply unit 70 for transferring the divided submount chip 101; LD chip supply unit 80 for transferring the divided LD chip 201; An image processing unit for aligning the divided chips: a submount junction head portion 72 for picking up the submount chip 101; An LD junction head portion 82 which picks up the LD chip 201; A light emitting point located between the LD chip upper camera 81 and the LD chip lower camera 84 of the image processing unit to find the light emitting point 301 and align the LD chip 201 on the stem 10. Detection unit 6 and the like. Referring to the drawings in more detail, each of the stems 10 supplied from the stem-loaded mega unit (1) on which a plurality of stems (10) are loaded is automatically conveyed by the conveyor unit (2), The stem supply takeout part 4 for supplying one stem 10 from the conveyor to the heater part 5 is located in one direction of the middle part of the conveyor part 2, and the stem supply takeout part 4 is located. The stem positioning device (not shown) for positioning the stem 10 in the heater block 50 of the heater unit 5 is located. The stem 10 inserted by the stem positioning device is fixed to the heater block 50 of the heater unit 5, and the LD chip 201 and the submount chip 101 are laminated and bonded to each other. At this time, the heater unit 5 is fixed to the central portion of the bonding device of the laser diode.

The submount chip supply unit 70 is located at one side of the heater unit 5, and the LD chip supply unit 80 is located at the other side of the heater unit 5, and each LD is divided in the supply units 70 and 80. The wafer 200 and the submount wafer 100 are transferred. First, in the place where the LD chip supply unit 80 is located, the image processing is performed such that the LD joint head 82 accurately picks up the LD chip 201 on the path where the LD chip 201 is transferred. Light emitting for positioning the LD chip 201 on the header 54 of the stem 10 by locating the light emitting point 301 on the outer portion of the LD chip 201, where the LD chip upper camera 81 is located. The point detection unit 6 is positioned, and the light emitting point detection unit 6 largely emits the power jig unit 60 and the LD chip 201 for applying power to the lower surface of the LD chip 201 so that the LD chip 201 emits light. It consists of a light emitting point recognition camera 61 for recognizing the light emitting point 301 of the LD chip 201, the LD chip 201 is bonded to the stem 10 after the light emitting point detector (6). The LD chip lower camera 84 is positioned as an image processing apparatus for finally aligning before the operation. In addition, in order to transfer the LD chip 201 from the LD chip supply unit 80, the LD junction head portion 82 is positioned in the junction head transfer portion 90 and moves along the rail of the junction head transfer portion 90. The collet 83 of the LD joint head 82 picks up the divided LD chip 201 by vacuum suction and transfers the same.

Where the submount chip supply unit 70 is located, the image processing is performed such that the submount junction head portion 72 accurately picks up the submount chip 101 on a path where the submount chip 101 is transported. The submount chip upper camera 71 is positioned, and the submount chip lower camera 74 is positioned as an image processing apparatus for finally aligning the submount chip 101 before bonding to the stem 10. do. In order to transfer the submount chip 101 from the submount chip supply unit 70, the submount junction head unit 72 is positioned at the junction head transfer unit 90 so that the rail of the junction head transfer unit 90 is located. It moves along, and the collet 73 of the submount junction head portion 72 picks up the divided submount chip 101 by vacuum suction and transfers it.

Using the above configuration, the stem 10 in which the LD chip 201 and the submount chip 101 are bonded to each other in the heater unit 5 may have the stem ejection mega through the stem supply and extraction unit 4. It is conveyed to the true part 3 and collected.

FIG. 5 is a configuration diagram of the light emitting point detector of the laser diode chip, which shows the main part of the present invention, and shows the light emitting point detector 6 shown in FIG. 4 in more detail. The light emitting point detecting unit 6 includes a power jig unit 60 for placing the LD chip 201 on an upper surface thereof; A plus probe pin 63 and a minus probe pin 64 for applying power to the LD chip 201; A light emitting point recognition camera 61 for image processing the laser beam 300 generated by the LD chip 201; And an image processing apparatus 65 for displaying the shadows projected on the light emitting point recognition camera 61, wherein the divided LD chip 201 is transferred to the LD junction head 82. It is picked up and placed on the power jig unit 60. Here, the upper surface of the power jig unit 60 is coated with a conductive material the upper surface of the power jig portion 62 so that the LD chip 201 is energized. Generally, when the LD chip 201 applies a current with a positive polarity to one side and a minus polarity to the other side, the light emitting point 301 is located at a predetermined position outside the LD chip 201. It is formed and emits light. Therefore, the light emitting point detector 6 is an intermediate step for locating the light emitting point 301 of the LD chip 201 and accurately positioning the light emitting point 301 on the center line of the header 54 of the stem 10. The light emitting point recognition camera 61 and the image processing apparatus 65 are used to correct the light emitting point 301 to be bonded. The positive probe pin 63 is contacted with an upper surface of the LD chip 201 positioned on the power jig unit 60, and a negative probe pin 64 is connected to the upper surface of the power jig unit 62. When power is applied to the chip 201, the LD chip 201 emits light to emit the laser beam 300. When the laser beam 300 emitted as described above is displayed by the image processing apparatus 65 with the shadow flowing through the light emitting point recognition camera 61, the light emitting point 301 is elliptical (circular depending on the LD chip). The distance of the light emitting point 301 of the LD chip 201 based on the center point of the light emitting point recognition camera 61 can be measured using advanced image processing technology. Therefore, if the distance is known, the position of the light emitting point 301 of the LD chip 201 is accurately known, and an eccentric distance of how far the light emitting point 301 is from the outside of the LD chip 201 is determined. It can be known and used as a reference to catch it as a baseline and to match it on the centerline of the header 54 of the stem 10.

6A is a state diagram in which a laser diode chip is bonded based on a light emitting point according to the present invention, and the light emitting point 301 of the LD chip 201 found using the light emitting point detector 6 is connected to the stem 10. The laser beam 300 emits light in accordance with the center line of the header 54 of FIG.

When the light emitting point 301 of the LD chip 201 is aligned and bonded on the center line of the stem 10 by using the light emitting point detector 6 according to the present invention as shown in FIG. The LD chip 201 may appear to be distorted, but since the center line of the outer edge is not important but where the light emitting point 301 is located, it is important to correct the position of the LD chip 201 and then bond the same. Only a stem package can obtain an incident rate of 100% when the laser beam 300 passes through the core of the optical fiber.

7 is a flowchart illustrating a method of bonding a laser diode and a submount chip, and the LD chip 201 and the submount chip 101 are attached to the stem 10 by using a laser diode bonding device according to the present invention. The method of bonding is shown step by step. The stem 10 is taken out from the stem-loading mega unit 1 on which the plurality of stems 10 are loaded, and is transported by the conveyor unit 2, and the stem 10 is taken out of the stem supply. It is supplied to the heater unit 5 through the unit 4 and fixed to the heater block 50, and the heater block 50 is heated to the header 54 of the stem 10. Or the submount chip 101 is maintained (1000). The submount chip 101 positioned on the submount chip supply unit 70 is aligned by the submount chip upper camera 71 and then adsorbed to the collet 73 of the submount junction head portion 72. And the stem 10 is moved to the position of the submount chip lower camera 74 so that the position is finally aligned 1001, and the stem 10 heated the aligned submount chip 101. On the header (1002). On the other hand, the LD chip 201 positioned on the LD chip supply unit 80 is aligned by the LD chip upper camera 81 and then adsorbed by the collet 83 of the LD junction head 82 to the LD chip 201. The light emitting point detecting unit 6 is placed on the power jig unit 60 (1003), and then power is supplied to the LD chip 201 using the plus probe pin 63 and the minus probe pin 64. The light emitting point 301 of the LD chip 201 is found by the light emitting point recognition camera 61 and the image processing apparatus 65 (1004). The LD chip 201 is finally aligned (1005) while passing through the LD chip lower camera 84 based on the light emitting point 301 of the LD chip 201 (1005), and then the LD chip 201 Is transferred 1006 to the header 54 of the heated stem 10. First, the submount chip 101 transferred to the stem 10 is bonded onto the header 54 of the stem 10 (1007), and the LD chip 201 on the top surface of the stem 10. By correcting the position difference between the outer edge of the light emitting point and the light emitting point 301 on the submount chip 101 bonded to the stem 10 (1008), by applying heat to the stem 10 again The LD chip 201 is bonded (1009). When both the LD chip 201 and the submount chip 101 are attached to the stem 10, the stem 10 is separated from the heater part 5 by the stem supply extracting part 4. Then, the laser diode is bonded to the stem-carrying unit 3 through the conveyor unit 2, and the stacking step 1010 is completed. Then, the stem is continuously connected to the laser diode bonding apparatus. 10 can be supplied to join many of the laser diodes in a short time by an automated process.

As described above, the present invention finds the light emitting point of the LD chip by adding a light emitting point detector to the existing method of recognizing and bonding the outer edge of the LD chip, and then actually joins the head of the stem around the light emitting point. Since the light emitting point of the LD can be located on the center line of the stem, and the LD chip is joined around the light emitting point of the LD chip, the scribing and breaking of the outside of the LD chip are performed. Since the error caused by (Breaking) can be ignored, 100% incident rate was obtained by attaching the optical fiber to the cap of the stem by using the stem package to which the LD chip was bonded. Productivity is improved because the process can save a lot of time. In addition, since the LD chip emits light first, it is not necessary to bond the defective LD chip to the stem and the subsequent process (wire bonding, screening and testing) does not go through the laser diode bonding apparatus and method which can greatly reduce the cost. Provided.

Claims (5)

A stem carrying mega section 1 on which the stem 10 is loaded; A conveyor unit 2 for conveying the stem 10; A stem carrying mega part (3) for collecting the joined stem (10); A heater unit 5 for joining the stem 10; A stem supply extracting part 4 for supplying the stem 10 to the heater part 5; A submount chip supply unit 70 for transferring the divided submount chip 101; LD chip supply unit 80 for transferring the divided LD chip 201; An image processing unit for aligning the divided chips; A submount junction head portion 72 which picks up the submount chip 101; In the conventional laser diode bonding apparatus comprising an LD junction head portion 82 and the like to pick up the LD chip 201, The image processing unit includes an LD chip upper camera 81 for aligning the LD chip 201, a LD chip lower camera 84, and a submount chip upper camera 71 for aligning the submount chip 101. And the submount chip lower camera 74, A light emitting point detecting unit located between the LD chip upper camera 81 and the LD chip lower camera 84 to locate the light emitting point 301 and align the LD chip 201 on the stem 10. Bonding device of a laser diode, characterized in that consisting of 6). The method of claim 1, The light emitting point detector 6 A power jig unit 60 for placing the LD chip 201 on an upper surface thereof; A plus probe pin 63 and a minus probe pin 64 for applying power to the LD chip 201; A light emitting point recognition camera 61 for image processing the laser beam 300 generated by the LD chip 201; And And an image processing apparatus (65) for displaying the shadows projected on the light emitting point recognition camera (61). The method of claim 2, The power jig unit 60 is a laser diode bonding device, characterized in that the upper surface is coated with a conductive material in order to energize the LD chip 201 located on the upper surface. In the method of bonding the LD chip 201 to the stem 10 using the bonding device of the laser diode, Supplying the stem (10) to the heater part (5) through the stem carrying mega part (1), the conveyor part (2), and the stem supply extracting part (3); Aligning (1001) the submount chip (101) supplied from the submount chip supply unit (70) to the image processing unit; Positioning (1002) the submount chip (101) on the stem (10) using the submount junction head portion (74); Arranging (1003) the LD chip 201 supplied from the LD chip supply unit 80 to the image processing unit; Finding (1004) the light emitting point (301) of the LD chip (201) by passing the aligned LD chip (201) through the light emitting point detector (6); Finally aligning the LD chip 201 with the light emitting point 301 of the LD chip 201 (1005); Transferring (1006) the LD chip (201) to the stem (10) using the LD junction head portion (82); Bonding (1007) the submount chip (101) to the stem (10); Correcting the position of the LD chip 201 and placing it on the stem 10 (1008); Bonding (1009) the LD chip (201) to the stem (10); And And taking out (1010) the stem (10) to which the submount chip (101) and the LD chip (201) are bonded. The method of claim 4, wherein The position correction method of the LD chip 201 Calculating an eccentric distance by calculating a displacement between the position of the laser beam 300 projected through the light emission point recognition camera 61 of the light emission point detection unit 6 and a center point of the light emission point recognition camera 61; Finding a light emitting point 301 of the LD chip 201 based on the eccentric distance; And Determining the distance from the outline of the LD chip 201 with respect to the light emitting point 301, and performing correction by matching the light emitting point 301 to the center of the stem 10; Joining method of a laser diode.