JPH07176549A - Die bonder - Google Patents

Abstract

(57) [Summary] [Purpose] To shorten the time required for melting the bonding agent when bonding the tip to the stem and to secure stable bonding strength. [Structure] The chip 1 is mounted on a stem 21, and a collet heater 34 is attached to a suction collet 31 which is pressurized.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding apparatus for mounting a semiconductor laser chip on a stem by melting and cooling a bonding agent.

2. Description of the Related Art Conventionally, when a semiconductor laser chip, for example, is die-bonded on a stem using a bonding agent on the stem, the chip is first aligned and a suction collet is used.
When they are adsorbed one by one, transferred onto the stem, and the chip is mounted on the stem, the heater in contact with the stem is energized,
The bonding agent on the stem is melted, held at an arbitrary temperature and cooled to bond. However, in order to secure the bonding strength, the chip mounted on the stem must be pressed against the surface of the chip by the adsorption collet mounting the chip when the heater is heated.

In the conventional method, since the tip is pressed by the suction collet or other means when the stem is heated, the heat of the stem is radiated from the suction collet, so that it takes time to melt the bonding agent. In addition, since the temperature of the tip of the suction collet is not controlled, the melting of the bonding agent on the lower surface of the chip becomes non-uniform, the bonding strength may vary, and the die bonding time is long.

In the die bonding apparatus of the present invention, a heater is attached to a means for pressing a chip onto a stem, such as a suction collet, during die bonding.

According to the present invention, since the heat is not radiated from the suction collet, the melting time of the bonding agent is shortened, and the bonding agent on the lower surface of the chip is melted uniformly, so that stable bonding strength between the chip and the stem can be ensured. The bonding time can be shortened.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of an embodiment of the present invention. The bonding stage 10 is an X that can move in a plane.
It is composed of a table 11, a mount base 12 provided on the X table 11, a stem heater 13 and a stem chuck 22 mounted on the table 11, and the temperature of the stem heater 13 is controlled by a heater controller 14. FIG. 2 is a perspective view of the stem chuck 22 and its vicinity. The stem chuck 22 is a stem 2 on which a bonding agent 21-2 supplied by a stem handler 20 described later is placed.
1 (a perspective view is shown in FIG. 3) is held, and the stem 21 is brought into contact with the stem heater 13 by the push rod 23 rising from the lower surface to position the stem 21.
Further, a stem cooling nozzle 24 and a nitrogen nozzle 25 for the purpose of preventing oxidation of the bonding agent are also installed on the mount base 12. Returning to FIG. 1, the stem handler 20 moves the stem holding device 28 up and down by the vertical stage 26, and
It is configured to be movable in the left-right direction by the stage 27. The suction collet moving stage 30 is a device for mounting the chip on the bonding agent of the stem 21, and the suction collet 31 for sucking the chip 1 moves up and down by the vertical stage 32 and moves left and right by the suction collet X stage 36. It is movable. Further, as will be described later, the suction collet 31 has a minute suction hole at the center thereof so that the chip 1 can be suction-fixed by an external vacuum source 33. Further, the collet heater 34 of the present invention is installed, for example, at the tip of the suction collet 31, and is temperature-controlled by the heater control device 35 to keep the portion of the suction collet 31 in contact with the chip at a constant temperature. 4 is a partially cutaway side view of the suction collet 31, FIGS. 5 (a) and 5 (b) are perspective views and cross-sectional views of a collet heater 34 attached thereto, and FIG. 6 is a suction with the collet heater 34 attached. It is a side view of an example of collet 31. As shown in FIG. 4, the suction collet 31
The upper part 31-1 is made of metal and has a stepped lower part 31
-2 is made of ceramic, and both are brazed. A suction hole 31-3 penetrates through the central portion. In use, the upper part of the through hole 31-3 is connected to a vacuum source, and the lower part adsorbs the chip. In the adsorption collet 31, in order to fix the collet heater 34 and to insulate the heat, the material of the portion where the adsorption collet 31 and the collet heater 34 are in contact is made of, for example, ceramic having low thermal conductivity. As shown in FIG. 5, the collet heater 34 is a wire rod 3 such as a nichrome wire.
By winding 4-1 in a cylindrical shape and connecting the heater lead wire to the heater control device 35, the temperature is controlled and the tip of the suction collet 31 can be kept at a constant temperature. Figure 5
Cylindrical heater 3 as shown in (a) and (b)
The fixing of No. 4 is determined by inserting it from the tip of the suction collet 31 and pulling it up to the stepped portion, and as shown in FIG.
The lead wire 4 can be fixed to the handle portion of the suction collet 31 by fixing it with a binding band 36 or the like. The heater can be embedded in the collet. Next, the operation sequence of this die bonding apparatus will be described. First, the stem 21
Is supplied to the bonding stage 10 from a stem supply stage 4 (not shown in detail) by the stem handler 20, the stem 21 is fixed by the stem chuck 22, and the stem heater 13 is brought into contact with and positioned by the push rod 23. On the other hand, the chip 1 is attached to a vacuum source 3 by a suction collet 31 by a supply unit 2 whose details are not shown (see, for example, Japanese Patent Application No. 5-180979 semiconductor laser chip supply device).
3 by vacuum suction, and is positioned by an alignment device 3 (see Japanese Patent Application No. 5-86208, a mounting direction adjusting mechanism of a semiconductor laser chip mounting device) not shown in detail, and a suction collet moving stage 30 and an upper and lower stage 32 cause the stem to move. Mounted on No. 21 to release the suction. At this time, the collet heater 34 at the tip of the suction collet 31 is kept at a constant temperature by the heater controller 35 for heating the suction collet, and the suction collet 31 and the chip 1 are also kept at a constant temperature. In this case, since the suction collet 31 pressurizes the tip 1 on the stem 21, the tip of the suction collet 31 is in contact with the tip 1. Next, the heater controller 14 for heating the stem heats the stem heater 13 to a predetermined temperature to melt a bonding agent such as indium and a brazing agent on the stem 21, and when the temperature reaches an appropriate temperature, the power of the heater is turned off. The stem 21 is cooled by blowing cooling air onto the stem 21 by the cooling nozzle 24, and the chip 1 is fixed onto the stem 21. During cooling, the power of the collet heater 34 of the suction collet 31 is also shut off at the same time. Next, the suction collet 31 is raised to pick up the next chip in the chip supply unit 2. On the other hand, the stem 21 after the bonding is completed, the stem chuck 22 and the push rod 23 are opened, the stem 21 is discharged by the stem handler 20, and the next stem 21 is supplied to the bonding stage 10. However, during the above work, nitrogen is constantly supplied from the nitrogen nozzle 25 to the stem 21 for the purpose of preventing the oxidation of the bonding agent.
It is sprayed toward the surface of the cement. The above operation completes the bonding for one stem. Bonding can be continuously performed by repeatedly performing the above-described series of sequences. In the above embodiment, an example in which a heater is attached to the suction collet is shown, but the suction collet is used to mount the tip on the stem, and the tip is pressed onto the stem by another collet with a heater attached. May be.

As described above, according to the present invention, the stability of the bonding strength between the stem and the tip can be increased and the heating time of the stem can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a perspective view of the vicinity of a stem chuck.

FIG. 3 is a perspective view of a stem.

FIG. 4 is a partially cutaway side view of a suction collet.

5A and 5B are a perspective view and a cross-sectional view of a collet heater, respectively.

FIG. 6 is a side view of a suction collet equipped with a collet heater.

[Explanation of symbols]

 1 Chip 2 Chip Supply Unit 3 Alignment Device 4 Stem Supply Unit 10 Bonding Stage 12 Mount Base 13 Stem Heater 21 Stem 31 Adsorption Collet 34 Collet Heater

Claims (1)

[Claims] 1. A die bonding apparatus for melting a bonding agent to cool a bonding agent to bond a semiconductor chip to a stem, wherein a heater is provided as a means for pressing the chip onto the stem.