JPH11251372A - Thermocompression bonding of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for thermocompression bonding a bumped electronic component, which is able to secure a corrected positional accuracy at the mounting of the component even at high temperatures. SOLUTION: In a thermocompression bonding apparatus, a substrate 3 mounted on a heater block 2 on a substrate stage 1a as well as an electronic component 5 held in a pushing head 6 are recognized and subjected to a positional correction for its positioning by an optical head 59 to push the component 5 against the substrate 3. A retreat space for the head 59 to retract from an image-pickup position is set in the movable range of a stage 1a, and a heat shielding plate for blocking the heat from the block 2 is provided below the retreat space. As a result, an electronic component thermocompression-bonding apparatus is realized which can have a compact arrangement with a reduced space, suppress deformation of the optical head 59 due to the heat of the block 2 and is thus able to avoid an improperly corrected positional accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocompression bonding apparatus for electronic components, such as a flip chip, which thermocompresses electronic components to a substrate.

[0002]

2. Description of the Related Art With the miniaturization of electronic components and the narrow pitch of wiring patterns, high precision is required for mounting electronic components on a substrate, such as deformation and displacement of the substrate. A method of correcting the position error of the mounting point caused by the image recognition by image recognition is widely used. In this method, before mounting the electronic component, the board or both the board and the electronic component are imaged by a camera, and the position of the board or the electronic component is detected based on the obtained image data. The correction is performed.

In the case where a bump is formed on the lower surface of a semiconductor element such as a flip chip, and the bump is bonded to an electrode of a substrate, the position of the bump needs to be obtained by image recognition in the above-described position correction at the time of mounting. is there.
For this reason, in order to image the bumps of the substrate and the flip chip with the same position reference, it is possible to simultaneously image the bumps of the substrate and the electronic components by positioning the camera between the pressure bonding head holding the flip chip and the substrate. Done. In this camera, an optical head having an optical system mounted on a movable arm is used because it is necessary to retreat from below the pressure bonding head when lowering the pressure bonding head and thermally bonding the flip chip to the substrate.

[0004]

However, in recent years, the temperature at the time of thermocompression bonding has become high, and it has become necessary to heat the substrate itself. For this reason, a heater may be built in the substrate stage that holds the substrate. In such a case, this heat is transmitted to and heated around the base supporting the optical head, and the optical axis of the optical head may be deviated by the deformation due to the heat. The displacement of the optical axis of the optical head naturally has a bad influence on the position accuracy of the image data, and causes a deviation in the position correction accuracy. As described above, in the thermocompression bonding of a flip chip which requires high-temperature mounting, there is a problem that a detection error due to heat occurs in position detection by image recognition, and the position correction accuracy during mounting cannot be ensured.

Accordingly, an object of the present invention is to provide a thermocompression bonding apparatus for electronic components with bumps, which can maintain the position correction accuracy during mounting even when performing high-temperature mounting.

[0006]

According to the present invention, there is provided a thermocompression bonding apparatus for electronic parts, comprising: a substrate stage having a heater block for mounting and heating a substrate, the substrate stage moving in a horizontal direction, and a lower surface above the substrate stage. A pressure bonding head for holding the electronic components and thermocompression bonding, an elevating means for raising and lowering the pressure bonding head, and moving to an imaging position between the pressure bonding head and the substrate stage to hold the electronic components held by the substrate and the pressure bonding head. Imaging means for imaging the component; correction means for correcting the displacement of the electronic component with respect to the substrate based on the imaging data of the imaging means; and an imaging position which is set above a movable range of the substrate stage and moves the imaging means. And a heat shield plate provided below the evacuation space and intercepting heat from the heater block.

According to the present invention, a retreat space set within the movable range of the substrate stage for retreating the image pickup means from the image pickup position, and a heat shield plate provided below the retreat space to block heat from the heater block are provided. By preparing
A thermocompression bonding apparatus for electronic components having a compact structure and capable of preventing poor position correction accuracy due to heat can be realized.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a side view of a thermocompression bonding apparatus for electronic components according to an embodiment of the present invention, FIG. 2 is a plan view of an imaging unit of the thermocompression bonding apparatus for electronic components, and FIG. FIG. 4 is a cross-sectional view of the imaging unit of the thermocompression bonding apparatus for the electronic component.

First, the structure of a thermocompression bonding apparatus for electronic components with bumps will be described with reference to FIG. In FIG. 1, XY
Substrate stage 1 horizontally moved by table 1
A heater block 2 provided with a heater for heating the substrate is provided on a. A substrate 3 is placed on the heater block 2, and a supply unit 4 for an electronic component 5 is disposed on the substrate stage 1 a on the side of the substrate 3. By driving the XY table 1, the substrate 3 and the supply unit 4 move in a horizontal plane. Above the XY table 1, an electronic component 5 is held by a crimping head 6, and the crimping head 6 is mounted on a first lifting block 10.

A slider 11 is fixed to the back surface of the first lifting block 10, and the slider 11 is vertically slidably fitted on a vertical guide rail 12 provided on the front surface of the first frame 13. doing. An inverted L-shaped overhang 14 is provided above the first lifting block 10. The lower surface of the overhang portion 14 is in contact with a load cell serving as load detecting means described later.

Above the first lifting block 10, a second lifting block 20 is provided. A slider 21 is provided on the back surface of the second elevating block 20, and the slider 21 is vertically slidably fitted on a vertical guide rail 22 provided on the front surface of the second frame 23. . An inverted L-shaped overhang 24 is provided below the second lifting block 20. A load cell 26 serving as a strain-type load detecting means is disposed on the upper surface of the overhang portion 24, and the load cell 26 is in contact with the lower surface of the overhang portion 24. A cylinder 25 is mounted on the lower surface of the second lifting block 20 in a downward direction.
Rod 25a is in contact with the upper surface of the overhang portion 24.

A bracket 30 having a U-shaped cross section is fixed to an upper portion of the second frame 23. Bracket 30
A motor 31 is provided on the upper side, and a rotating shaft of the motor 31 is connected to a vertical feed screw 27. Feed screw 2
7 is screwed into a nut 28 built in the second lifting block 20. Therefore, when the motor 31 rotates forward and backward, the nut 28 moves up and down along the feed screw 27, and the second lifting block 20 and the first lifting block 10 move up and down. That is, the motor 31, the feed screw 27 and the nut 2
8 is a crimping head 6 together with the first lifting / lowering block 10
As a lifting means.

The motor 31 is connected to a lift motor drive unit 33, and the lift motor drive unit 33 receives a command from the control unit 43 and controls the rotation of the motor 31. An imaging section 39 is provided below the first frame 13. The imaging unit 39 includes an optical head 59 protruding forward, and the optical head 59 is moved from a retracted position indicated by a solid line in FIG.
The electronic component 5 and the substrate 3 are imaged by advancing to an imaging position indicated by a chain line between the pressure bonding head 6 and the substrate stage 1a.
Therefore, the optical head 59 of the imaging unit 39 is an imaging unit.

An image recognition section 37 is connected to the image pickup section 39, and the image recognition section 37 is connected to the control section 43. The image data captured by the imaging unit 39 is transmitted to the image recognition unit 3.
The position data of the board 3 and the electronic component 5, which are sent to the control unit 7 and recognized by the image recognition unit 37, are sent to the control unit 43. The control unit 43, based on these position data,
The displacement of the electronic component 5 is corrected. Therefore, the imaging unit 39, the image recognition unit 37, and the control unit 43 function as a correction unit that corrects the positional shift of the electronic component 5. The bonding load detection unit 34 detects a bonding load based on the load value detected by the load cell 26. The motor drive unit 36 drives a motor that moves the optical head 59 forward and backward. The XY table driving unit 42 is an XY table 1
Drive.

Next, the imaging section 39 will be described with reference to FIGS. 2 and 3, four pillars 50 are erected on the XY table 1, and a plate 51 is fixed to the upper end of the pillar 50. A pair of guide rails 52 is provided on the upper surface of the plate 51, and a slider 53 slidably mounted on the guide rail 52 is fixed to the lower surface of the plate 54.

A motor 55 is provided on the plate 51, and a feed screw 56 driven by the motor 55 is screwed into a nut (not shown) fixed to the plate 54. A guide rail 57 is disposed on the upper surface of the plate 54 in the X direction, and a slider 58 is mounted on the guide rail 57. An optical head 59 is fixed to the slider 58. An imaging lens 60 is mounted on the tip 59 a of the optical head 59.

By driving the motor 61 and the motor 55, the optical head 59 moves horizontally in the X and Y directions, and picks up an image between the electronic component 5 and the substrate 3 held by the pressure bonding head 6 as shown in FIG. Advance to the position (indicated by the dashed line). Similarly, the optical head 59 retracts from the imaging position and retracts below the plate 51. That is, the space below the plate 51 is a retreat space in which the optical head 59 as the image pickup means retreats, and this retreat space is set above the movable range of the substrate stage 1a as described later.

In FIG. 3, the lower surface of the plate 51 has a Y
A duct 63 is provided so as to communicate in the directions. Duct 6
3, an air hose 64 is connected, and air supplied from an air source (not shown) blows into the duct space 63a, and the air (arrow a) flows around the optical head 59 as shown in FIG. To cool. Duct 6
A heat shield plate 65 is provided below substantially 3 over substantially the entire range of the plate 51. As shown in FIG. 4, the substrate stage 1a moves to the position indicated by the chain line 1a in the direction of arrow b, that is, below the refuge space during the thermocompression bonding of the electronic component 5a on the substrate 3. At this time, the heater block 2 is 40
Since the image is heated to about 0 ° C., the imager 39 is affected by this heat. The heat shield plate 65 is for blocking the transmission of radiant heat from the heater block 2 to the imaging unit 39.

As shown in FIG. 2, two cooling fans 66 are mounted on the plate 51, and air is sent into a space 66 (see FIG. 3) between the heat shield plate 65 and the plate 51, and the heat shield is provided. The temperature of the plate 65 is prevented from rising. As described above, the thermal effect of the heater block 2 is firstly blocked by the heat shield plate 65 for the radiant heat, the space 66 on the heat shield plate 65 is cooled by the cooling fan 66, and the space 63a in the duct is blown by air blow. Always cool. Therefore, the optical head 59 having this space as a retreat space is effectively protected from the heat of the heater block 2, and does not generate thermal deformation which affects the position correction accuracy.

This thermocompression bonding apparatus for electronic components is configured as described above, and the operation will be described below. First, in FIG. 1, the XY table is driven to position the supply unit 4 below the pressure bonding head 6. Then, the lifting / lowering motor 31 is driven to lower the pressure bonding head 6, and when the electronic component 5 is picked up and held, the pressure bonding head 6 is raised. Next, the substrate 3 is positioned below the pressure bonding head 6, the motor 55 is driven to advance the optical head 59, and is stopped at an imaging position immediately below the pressure bonding head 6. Then, the light incident on the lens 60 is captured to image the substrate 3 and the electronic component 5. The positions of the board 3 and the electronic component 5 are recognized by the image recognition unit 37 based on the image data. The control unit 43 drives the XY table 1 based on the recognition result, corrects the position of the mounting point, and transfers the electronic component 5 held by the pressure bonding head 6 to the substrate 3.
Thermocompression bonding.

In this thermocompression bonding operation, when high-temperature mounting is performed, the heater block 2 on which the substrate 3 is mounted is heated, and the surroundings are affected by performing thermocompression continuously for a long time. Also in this case, since the heat shield plate 65 is provided in the evacuation space of the imaging unit 39 as described above and further cooled by the cooling fan 66 and the air blow, the optical position is higher than the movable range of the substrate stage 1a. Even if the evacuation space of the head 59 is set, the optical head 59
Does not undergo thermal deformation. Therefore, the position correction accuracy defect due to the optical head 59 being deformed and the optical axis of the lens 60 being displaced does not occur.

Further, since a countermeasure against the thermal influence of the heat block 2 is taken, a retreat space for the optical head 59 of the image pickup section 39 can be arranged within the movable range of the substrate stage 1a, so that the space is reduced and the space is reduced. It is possible to realize a thermocompression bonding apparatus.

[0023]

According to the present invention, an evacuation space set within the movable range of the substrate stage for evacuation of the imaging means from the imaging position, and a heat shield provided below the evacuation space to shut off heat from the heater block. Since the plate is provided, it is possible to realize a thermocompression bonding apparatus for electronic components that has a compact structure and does not cause poor position correction accuracy due to heat.

[Brief description of the drawings]

FIG. 1 is a side view of a thermocompression bonding apparatus for electronic components according to an embodiment of the present invention.

FIG. 2 is a plan view of an imaging unit of the electronic component thermocompression bonding apparatus according to the embodiment of the present invention.

FIG. 3 is a front view of an imaging unit of the thermocompression bonding apparatus for electronic components according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view of an imaging unit of the thermocompression bonding apparatus for electronic components according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 XY table 1a Substrate stage 2 Heater block 3 Substrate 5 Electronic component 6 Crimping head 31 Motor 36 Motor driving unit 37 Image recognition unit 39 Imaging unit 43 Control unit 59 Optical head 65 Heat shield plate 66 Cooling fan

Claims (1)

[Claims] 1. A substrate stage having a heater block for mounting and heating a substrate thereon, the substrate stage moving in a horizontal direction, a pressure bonding head for holding an electronic component on a lower surface above the substrate stage and performing thermocompression bonding. Elevating means for raising and lowering the pressure bonding head; imaging means for moving to an imaging position between the pressure bonding head and the substrate stage to image the substrate and the electronic components held by the pressure bonding head; Correction means for correcting the displacement of the electronic component with respect to the substrate based on the evacuation space, which is set above the movable range of the substrate stage to evacuate the imaging means from the imaging position, and which is provided below the evacuation space. A thermocompression bonding apparatus for electronic components, comprising: a heat shield plate that blocks heat from the heater block.