JP2012114382A - Bonding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide means which produces substrates on which chips have been tentatively placed in a previous process and simplifies a bonding head, thereby increasing the operating speed with a small structure and improving work efficiency.SOLUTION: In a state 23 where a chip 20 is tentatively placed on a substrate 21, a bonding head 30 moves down and a position where the bonding head 30 contacts with the chip is measured by a force sensor 31. Then, the chip is suctioned and the holding height is adjusted. The chip is heated and cooled by a pulse heater 38. This operation process increases the production speed.

Description

The present invention relates to, for example, a bonding apparatus and a bonding method for mounting (bonding) a semiconductor chip or a semiconductor component (hereinafter referred to as a chip) on a surface of a substrate via solder bumps (solder bump electrodes or solder balls).

Semiconductor chip mounting methods are mainly wire bonding and TAB (Tape Automated).
There are three methods: Bonding) and Flip Chip Bonding.
In flip chip bonding, it is necessary to fix a semiconductor chip on this printed circuit board with its active terminal surface facing the printed circuit board (face-down state).
As described above, in the case of flip-chip bonding, there is a technique that uses a protruding electrode made of solder called a solder bump as a connection medium with the substrate.
In the case of the connection using the solder material, in the case of flip chip, the solder material is supplied on the semiconductor chip and the substrate in advance, and the solder material is remelted by heating and then solidified. It is like that.

Japanese Patent Application No. 7-312125 has been proposed as a conventional example of the present invention. The electrode pad 911 is transported by the bonding tool 94 to the substrate 94 placed on the bonding stage 99 so as to face the solder bumps 93 placed on the chip 90.
The bonding tool 94 is configured so that the chip 90 can be sucked and held at the lower end by sucking from the suction hole 95.
Further, the bonding tool 94 is provided with a heat generating portion 98, and when the heat generating portion 98 is heated, the chip 90 can be heated and the solder bump 93 can be dissolved.
The bonding tool 94 can be moved by a tool holder 97. The tool holder 97 is provided with a laser displacement meter 96, and the height of the bonding tool 94 can be measured by irradiating the laser 961.

By the measurement of the laser displacement meter 96, the bonding tool 94 is controlled as shown in the graph (2) of FIG. The bonding tool 94 holding the chip 90 is moved onto the substrate 91 placed on the bonding stage 99 by the tool holder 97, and the position is adjusted so that the solder bump 93 and the electrode pad 911 are accurately bonded.
Thereafter, as indicated by points A to B in the graph (2) of FIG. 4, the bonding tool 94 descends at a high speed, and the solder bump 93 contacts the electrode pad 911 at the point B.

Thereafter, the position of the bonding tool 94 is once lowered by about 20 μm from point C to point D. At this time, the thermocouple 98 is heated to raise the temperature of the bonding tool 94, and the solder bump 93 attached to the chip 90 between the points D to E is melted and joined to the electrode pad 911.
Next, the bonding tool 94 is raised from the point E to the point F, the position is controlled to adjust the distance between the chip 90 and the substrate 91, and the soldering is completed by cooling at a predetermined position.

Next, the chip 90 is cooled between the points F to G. The suction holding of the chip 90 is released at the point G, and the bonding tool 94 that has opened the chip 90 between the points G and H rises at a high speed.
With the configuration and control as described above, the chip 90 is bonded to a predetermined position on the substrate 91.

Japanese Patent Application No. 7-312125

  According to the conventional example as described above, the chip 90 held by suction must be accurately positioned. For this purpose, the bonding tool 94 must be equipped with a rotation mechanism in addition to the vertical movement, and further, since the chip 90 must be accurately installed while descending, the analysis speed can be increased with a high-analysis camera for image processing. As a result, the overall structure becomes complicated and the control method requires a large amount of programs. For the reasons described above, processing for finishing one product takes time.

  Further, in the method for measuring the holding height h of the semiconductor chip using the laser displacement meter 96 as shown in FIG. 4 (1), the distance between the substrate 91 and the chip 90 may not be accurately measured. For example, the temperature of the bonding tool 94 as a whole is increased by the influence of the heat generating portion 98 that repeatedly generates heat, and the entire length of the bonding tool 94 changes due to the heat effect, and the holding height h of the semiconductor chip 90 may differ.

  Furthermore, in order for the bonding stage 99 to make it easier for solder to adhere to the electrode pads 911 of the substrate 91, it is necessary to raise the temperature of the bonding stage 99 and to heat the substrate 91.

Since the heat that heats the bonding stage 99 is transmitted to the entire device and changes various places due to the thermal effect, the distance between the tool holder 97 and the bonding tool 94 is measured using a laser 961 as shown in (1) of FIG. However, the exact distance between the chip 90 and the substrate 91 cannot be measured, and a defective product may be manufactured.

  An apparatus for bonding an electronic component in a state where a substrate and a chip are temporarily placed with a solder material interposed therebetween, wherein a head capable of moving up and down by sucking and holding the chip, and a contact position where the head contacts the chip A force sensor for determining; a pulse heater for heating and cooling the head; and a control unit for controlling the head, the force sensor, and the pulse heater, wherein the head is temporarily placed on the substrate. The contact position is determined by the force sensor, the chip is adsorbed by the head, the gap between the substrate and the chip is made constant, and the head and the chip are heated by the pulse heater. The present invention proposes a bonding apparatus characterized in that the control unit controls the solder material interposed between the substrate and the chip to melt.

The present invention proposes a bonding apparatus in which a plurality of the heads are mounted.

  In the present invention, the chip is preliminarily placed in the main body 1 in a state 23 temporarily placed on the substrate 21 in the previous step. A solder 24 put between the chip 20 and the substrate 21 is stuck at a predetermined position and temporarily placed on the substrate 21. Therefore, the bonding head 30 is lowered and the position where the head lower end 301 is in contact with the chip 20 is measured by the force sensor 31, and the holding height H of the semiconductor chip is adjusted from the measurement position. For this reason, the bonding head 30 can be adjusted so that the chip 20 is sucked and held at a certain height even if the positioning function is not highly accurate, so that the structure can be simplified and the lowering speed can be increased. And the production speed can be increased.

In addition, since the program for controlling by the control unit 5 can be simple and can be executed in a short time, a plurality of bonding heads 30 can be equipped, and a plurality of chips 20 and the substrate 21 can be soldered by one unit and mass production efficiency is achieved. Rose.

Even if the bonding head 30 and the bonding stage 35 may change due to thermal effects due to continuous use for a long time, as shown in (2) of FIG. Since H is detected and the height H is adjusted from that position, there is little error in the height H due to the thermal effect of the apparatus, and accurate control can be performed, so that the generation of defective products can be suppressed.

In order to solder a large number of temporarily placed substrates 23, the bonding stage 35 is more efficient in terms of heat retention and thermal efficiency when it is made larger. In addition, even if the mounting height of the temporarily mounted substrate 23 changes due to the thermal effect of the bonding stage 35, the height is adjusted after the bonding head 30 contacts the chip 20, so the change due to the thermal effect Accurate soldering operations are performed that are not easily affected.
Since a plurality of chip temporarily placed substrates 23 are soldered with a plurality of bonding heads 30, a uniform product can be manufactured with a short tact.

  FIG. 1 is an external view of the invention according to the invention. 2 (1) to (4) illustrate the operation of the bonding head 30. FIG. FIG. 3 is a flowchart showing the operation flow of the main body 1.

  The outline of the present invention will be described with reference to FIG. The substrate is supplied in a state where the chip temporarily placed substrate 23 is packed in the carrier 42 supplied by the substrate loader 44. The carrier 42 is transferred to the bonding stage 35 at the center of the main body 1 by a feeding mechanism such as a conveyor 47.

The main body 1 is provided with a control unit 5, and all control of the main body is controlled by the control unit 5. The carrier 42 storing the chip temporarily placed substrate 23 transferred to the bonding stage 35 moves to the lower part of the bonding head 30.
In FIG. 1, six bonding heads 30 are shown, and six of the chip temporarily placed substrates 23 stored in the carrier 42 can be soldered together.

When the carrier 42 containing the chip temporarily placed substrate 23 is transferred to the lower part of the bonding head 30, the six bonding heads are lowered by the driving of the six bonding head Z-direction moving units 40 to perform the soldering operation. .
The carrier 42 shown in FIG. 1 stores 18 chips temporarily placed on the substrate 23, and since there are 6 bonding heads 30, all the chips temporarily placed on the substrate 23 in the carrier 42 are placed in 3 steps. The soldering operation is completed.
When the positions of the bonding head 30 and the carrier 42 are shifted, adjustment in the X direction is performed by the bonding head X direction moving unit 41, and adjustment in the Y direction is performed by moving the bonding stage 35.
However, even if the suction hole 32 of the bonding head 30 deviates from the center of the chip 20, it is sufficient that the chip 20 can be sucked and held while the solder is melted, so that fine adjustment in the X and Y directions is not required.

An interval H or an operation between the bonding head 30 and the chip temporarily placed substrate 23 is captured by the gap observation camera 46, and is analyzed and controlled by the control unit 5 so as to be a predetermined interval.
The carrier 42 after the soldering operation is transferred to the original position of the through conveyor 47, pushed out as it is, and stored in the case of the board unloader 45, and the soldering operation is completed.

The solder work portion of the main body 1 is surrounded by a case 491, and the working apparatus is made a clean room through a fan 49 and a filter (not shown) to clean the air.
The bonding operation is performed in the above process.

Next, (1) to (4) in FIG. 2 will be described. FIG. 2 (1) shows a state where the chip temporarily placed substrate 23 is placed under the bonding head 30. A solder material such as a solder ball is already attached between the chip 20 and the substrate 21 at a predetermined position.
Further, the bonding stage 35 is warmed, the substrate 21 is warmed, and the solder 24 is easily dissolved.

Next, (2) of FIG. 2 shows a state in which the bonding head 30 is lowered by the bonding head Z direction moving portion, and the head tip portion 301 is in contact with the chip 20.
At this time, the chip 20 and the substrate 21 are held at an interval of height H.

  When the contact of the head tip 301 with the chip 20 is detected as a load change of the bonding head 30 by the force sensor 31 and transmitted to the control unit 5, the bonding head Z-direction moving unit 40 immediately stops, and the position thereof is the chip. Stored as 20 initial positions.

Thereafter, as shown in FIG. 2 (3), air is sucked from the suction holes 32, and the chip 20 is sucked and held by the bonding head 30 without changing the position of the bonding head 30.
Next, the pulse heater 38 is heated while the chip 20 is adsorbed and held while the bonding head 30 moves at a preset distance F to J (but there is a setting that does not move at all), and the solder 24 is melted as shown in FIG. The position of the bonding head 30 in the Z direction is adjusted so that the state shown in (4) is obtained.

  As a result, the solder 241 melted in a drum shape is completed as shown in (4) of FIG. 2, and the heating of the pulse heater 38 is stopped as it is, thereby completing the soldering as shown in (4) of FIG.

With the configuration as described above, the solder is prevented from being connected to each other by utilizing the action that the solder 24 melts and tries to stay at that position by the surface tension.
In this way, if the position of the chip 20 is too low, the surface tension of the melted solder is broken and the neighbors are connected to each other, and if the position of the chip 20 is too high, the surface tension of the melted solder is exceeded. . The bonding head 30 is controlled so that the position of the chip 20 is set in advance so that such a situation does not occur.
Thereafter, the suction from the suction hole 32 is stopped, the chip 20 is opened, and the soldering operation of the chip 20 is completed.

  As described above, the bonding head 30 only needs to move up and down and does not need to rotate, so that the weight can be reduced. Furthermore, since the adjustment position of the chip 20 is determined by the force sensor 31 and the bonding head Z direction moving unit 40, a complicated configuration is not required and the working speed can be increased.

  When it is considered that the entire machine has been thermally expanded due to thermal effects, etc., the dummy chip temporarily placed substrate is placed on the bonding stage 35, the bonding head 30 is lowered, and the head tip contacts the dummy chip. If this position is set as the reference position, the overall thermal expansion can be eliminated. The error due to thermal expansion may be measured once for several minutes to several tens of minutes.

  Even with the conventional bonding tool 94 shown in FIG. 4, errors due to thermal expansion can be eliminated by performing the same reference point adjustment, but the adsorption part of the chip 90 and the measurement part by the laser 961 are separated. There are cases where errors due to heat effects cannot be resolved.

  Since the apparatus of the present invention does not need to consider placing the chip 20 accurately, the bonding head 30 does not require a rotation mechanism. This is because the chip 20 is already supplied in a state of being placed on the substrate 21, so that position control in the rotation direction of the chip 20 is not necessary.

In addition, since the present invention is based on the position where the head tip is in contact with the chip 20, the error is so small that it does not cause a big problem even if an error occurs due to thermal effects. The working speed can be greatly improved by the bonding head 30 that eliminates a useless mechanism.

  FIG. 3 shows a flowchart of the carrier 42 carried into the apparatus 1 according to the present invention. As shown in FIG. 1, there is a through conveyor 43 that allows the carrier 42 to flow to another line.

As described above, in the present invention, the chip 1 is previously loaded in the main body 1 in a state 23 temporarily placed on the substrate 21 in the previous process. A solder 24 put between the chip 20 and the substrate 21 is stuck at a predetermined position and temporarily placed on the substrate 21. Therefore, the bonding head 30 is lowered and the position where the head lower end 301 is in contact with the chip 20 is measured by the force sensor 31, and the holding height H of the semiconductor chip is adjusted from the measurement position.
For this reason, the bonding head 30 can be adjusted so that the chip 20 is sucked and held at a certain height even if the positioning function is not highly accurate, so that the structure can be simplified and the lowering speed can be increased. And the production speed can be increased.

In addition, since the program for controlling by the control unit 5 can be simple and can be executed in a short time, a plurality of bonding heads 30 can be equipped, and a plurality of chips 20 and the substrate 21 can be soldered by one unit and mass production efficiency is achieved. Rose.

Furthermore, even if the bonding head 30 and the bonding stage 35 change due to thermal effects due to continuous use for a long time, as shown in FIG. 2 (2), the bonding head 30 has a high contact position on the chip 20 temporarily placed substrate 23. Since the height H is detected and the heights F to J are adjusted from that position, there is little error in the height H due to the thermal effect of the device, accurate control can be performed, and the generation of defective products can be suppressed. it can.

In order to solder a large number of temporarily placed substrates 23, the bonding stage 35 is more efficient in terms of heat retention and thermal efficiency when it is made larger. Even if the mounting height of the chip temporary placement corner substrate 23 changes due to the thermal effect of the bonding stage 35, the height is adjusted after the bonding head 30 contacts the chip 20, so the change due to the thermal effect Accurate soldering operations are performed that are not easily affected.

Since a plurality of temporarily placed substrates 23 are soldered with a plurality of bonding heads 30, a uniform product can be manufactured with a short tact.

The present invention can be applied to mounting solder members having various shapes.

It is a perspective view of the whole bonding apparatus. The operation of the bonding head is illustrated. It is a flowchart of operation | movement of a bonding apparatus. Graph of holding height of conventional bonding tool and chip

1 Bonding device body
5 Control unit
20
Chip
twenty one
substrate
23 Chip temporarily placed substrate
twenty four
solder
241 Solder dissolved in a drum shape
30
Bonding head
301 Head tip
31
Force sensor
32
Suction hole
35 Bonding stage
38 Pulse heater
40
Bonding head Z direction moving part
41
Bonding head X direction moving part
42
Career
43
Through conveyor
44
Board loader
45
Board unloader
46
Gap observation camera
47
Conveyor
49 fans
491
Case
90
Chip
91
substrate
911
Electrode pad
93 Solder bump
94
Boarding tools
95
Suction hole
96
Laser displacement meter
961 Laser (light)
97
Tool holder
98
Heat generation part
99
Bonding stage

Claims (2)

An apparatus for bonding electronic components in a state where a substrate and a chip are temporarily placed with a solder material interposed therebetween,
A head capable of moving up and down by sucking and holding the chip;
A force sensor for determining a contact position where the head contacts the chip;
A pulse heater for heating and cooling the head;
A control unit for controlling the head, the force sensor, and the pulse heater;
The force sensor determines a contact position where the head contacts the chip temporarily placed on the substrate, and the chip is sucked by the head so that a gap between the substrate and the chip is constant. The control unit controls the temperature of the head and the chip with the pulse heater to melt the solder material interposed between the substrate and the chip.


2. The bonding apparatus according to claim 1, wherein a plurality of the heads are mounted.

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