JP2000150970A - Light emitting device bonding method and equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the emission center of a light emitting device to be very accurately positioned at a prescribed point on a board without being affected by variations in the external shape of the light emitting device. SOLUTION: A light emitting device bonding equipment is equipped with a probe 16, which makes the LED chip 14 start emitting light before an LED chip 14 is bonded on a board 12, an imaging means 18, which recognizes the emission center of the LED chip 14 and does image recognition of the external shape reference point coordinates of the LED chip 14 with respect to the recognized emission center, and a light emitting device holding means 20 which positions the LED chip 14 at a bonding position on the board 12, resting on the basis of the external shape reference point coordinates subjected to image recognition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device bonding method and apparatus for bonding a light emitting device to a predetermined position on a substrate.

[0002]

2. Description of the Related Art In general, a light emitting element array in which a plurality of LDs or LEDs are arranged is employed as a light source for reading or outputting (recording) an image. For example, FIG.
As shown in FIG. 6, the LED array 1 is configured by arranging a plurality of LED chips (light emitting elements) 3 on a substrate 2 at equal intervals in one direction. In addition, the LED chip 3
The gold wire 4 is led out from each LED chip 3 by being bonded onto the substrate 2 via a silver paste.

In this type of LED array 1, each LE chip is so arranged that the distance between the light emitting centers of the LED chips 3 is equal.
It is necessary to align the D chip 3 on the substrate 2 with high precision. For this reason, for example, an automatic diponder disclosed in JP-A-6-216170 is known. In this conventional technique, a solid-state imaging device is moved between a semiconductor device and a work to which the semiconductor device is joined, and an upper solid-state imaging device captures a mark of a semiconductor device, while a lower solid-state imaging device marks a work mark. I'm shooting. Then
After the relative position relation between the semiconductor element and the work is calculated by the processing control unit, the bonding is performed by adjusting the relative position relation between the semiconductor element and the work based on the calculation result.

[0004]

SUMMARY OF THE INVENTION However, LEDs
In a chip, a position shift usually occurs between the emission center and the center of the external shape. For this reason, even if the alignment between the LED chip and the substrate is performed by aligning the alignment marks provided respectively,
There is a problem that it is not possible to effectively cope with variations in the light emission center of the chip.

[0005] In addition, the LED chip has a large variation particularly in its outer shape, and the LED chip is likely to shift when recognizing the center position of the outer shape. This allows
It is difficult to accurately position the emission center of each LED chip, and it has been pointed out that a high-precision LED array cannot be formed.

The present invention is intended to solve this kind of problem, and is not affected by variations in the light emission centers and outer shapes of the light emitting elements. It is an object of the present invention to provide a method and an apparatus for bonding a light emitting element that can be easily positioned.

[0007]

In the method and apparatus for bonding a light emitting element according to the present invention, first, the light emitting element is caused to emit light before bonding to recognize the light emitting center of the light emitting element. Image coordinates of the outer reference point of the light emitting element with respect to the coordinates are recognized. Next, the light emitting element is positioned at a bonding position on the substrate based on the image-recognized outer shape reference point coordinates, and the light emitting element is bonded on the substrate.

[0008] This makes it possible to position the emission center of the light emitting element with respect to a desired position on the substrate with high accuracy without being affected by the variation of the emission center and the variation of the outer shape of each light emitting element. Will be possible. Therefore, when bonding a plurality of light emitting elements on a substrate, the distance between the light emitting centers of each light emitting element can be positioned at equal intervals and with high precision, and a high quality light emitting element array can be easily manufactured. Become.

Here, the light emitting means for causing the light emitting element to emit light and the light emitting element holding means can advance and retreat in a direction intersecting the optical axis direction of the imaging means. Therefore, the alignment process between the light emitting element and the substrate is performed with high precision via the fixed imaging means.

A plurality of chips are connected to the light emitting element. One chip is used as a light emitting chip, and the other chip functions as a suction chip for holding the light emitting element. As a result, it is possible to emit light while holding the light emitting element, and it is possible to reliably prevent the occurrence of misalignment when the light emitting element is attracted.

[0011]

FIG. 1 is a schematic perspective view of a bonding apparatus 10 for carrying out a light emitting element bonding method according to an embodiment of the present invention, and FIG. 2 is a side view of the bonding apparatus 10. FIG.

Before bonding the LED chip 14 as a light emitting element on the substrate 12, the bonding apparatus 10 recognizes a probe 16 as a means for emitting light from the LED chip 14 and a light emission center of the LED chip 14. The LED chip 1 with respect to the coordinates of the recognized light emission center
Imaging means 18 for recognizing the coordinates of the outer shape reference point 4
And light emitting element holding means 20 for positioning the LED chip 14 at a bonding position on the substrate 12 based on the image-recognized coordinates of the external reference point.

A platen 22 constituting the bonding apparatus 10
A moving mechanism 26 is provided on the upper surface 24 of the. The moving mechanism 26 includes a first moving stage 30 that can move in the Y-axis direction of a rectangular coordinate system via a first motor 28, and a second motor 32
And a second moving stage 34 that can move in the X-axis direction of the orthogonal coordinate system with respect to the first moving stage 30 via the first moving stage 30.

The first moving stage 30 has a pair of guide rails 36a and 36b extending in the Y-axis direction.
A ball screw 38 disposed between the guide rails 36a and 36b and extending in the Y-axis direction. An output shaft of the first motor 28 is connected to one end of the ball screw 38.
A nut member (not shown) provided on the Y-axis movable table 40 is screwed to the ball screw 38, and the Y-axis movable table 40 is supported by guide rails 36a and 36b.

The Y-axis movable table 40 is configured to be long in the X-axis direction.
A pair of guide rails 4 constituting the second moving stage 34
2a and 42b and a ball screw 44 arranged between the guide rails 42a and 42b are arranged to extend in the X-axis direction. The output shaft of the second motor 32 is connected to one end of the ball screw 44, and the ball screw 44 is screwed to a nut member (not shown) provided on the X-axis movable table 46.

On the upper surface 48 of the X-axis movable table 46, a chip wafer 50 from which a plurality of LED chips 14 are cut out.
And a θ stage 54 for correcting the rotational position of each LED chip 14,
And a substrate suction table 56 for holding the substrate 2 by suction. stage 54 includes a rotary table 58 that is rotatable around the Z axis via an actuator (not shown).

A column 60 is provided upright on one end of the surface plate 22. The column 60 is provided with a driving means 62 capable of moving the probe 16 and the light emitting element holding means 20 in the Z-axis direction and the X-axis direction. The driving means 62 includes a column 60
A third motor 66 is fixed to one end of the frame 64, and the third motor 66 is fixed to the vertical surface of the third motor 66.
A ball screw 68 is connected to the output shaft of the motor 66. An X-axis table 70 is mounted on the ball screw 68. The X-axis table 70
2 is fixed.

A fourth motor 74 is fixed to an upper portion of the frame 72, and a ball screw 76 connected to an output shaft of the fourth motor 74 extends in the Z-axis direction and engages with a lift 78. The elevating table 78 is provided with a collet member 80 constituting the light-emitting element holding means 20, and a negative pressure generating source (not shown) communicates with the collet member 80. Lifting table 78
, A probe 16 is fixed, and a contact 82 that is inclined with respect to the Z-axis direction is provided on the distal end side of the probe 16.

The column 60 is provided with an arm 84 constituting the image pickup means 18.
D cameras 86 and 88 are mounted so as to be oriented in the Z-axis direction and the X-axis direction, respectively. A bifocal optical system 90 is provided on the optical axes of the CCD cameras 86 and 88. Surface plate 22
An image processing unit 100 for inputting images picked up by the CCD cameras 86 and 88 and performing image processing to recognize the coordinates of an outer shape reference point L1 (described later) of the LED chip 14 is arranged on the side of. Has been established.

The bonding apparatus 1 configured as described above
The operation of No. 0 will be described below based on the flowcharts shown in FIGS.

First, the substrate 12 is set on the substrate suction table 56. The substrate 12 is positioned so that an edge in the X-axis direction is aligned with a station reference plane (not shown), and is sucked from a suction hole (not shown) provided on the substrate suction table 56 so as to be positioned on the substrate suction table 56. Is held by suction. On the other hand, a plurality of LED chips 14 are arranged on the chip placement table 52 in a wafer shape.

Then, the moving mechanism 26 is driven, and the chip placement table 52 is placed at a position corresponding to the camera center of the image pickup means 18, that is, at a chip take-out position (step S1). In the moving mechanism 26, when the first motor 28 is driven, the Y-axis movable table 40 moves in the Y-axis direction under the rotation of the ball screw 38, and
When the ball screw 44 is rotated by the driving action of the motor 32, the X-axis movable table 46 moves in the X-axis direction. Therefore, by controlling the driving of the first and second motors 28 and 32, the LED chips 14 arranged at predetermined positions on the chip placement table 52 are arranged corresponding to the chip pick-up positions.

Next, a predetermined LED chip 14 on the chip placement table 52 is imaged via the CCD camera 86, for example, which constitutes the image pickup means 18 (step S2).
The image signal of the LED chip 14 picked up by the CCD camera 86 is sent to the image processing unit 100 and subjected to image processing.
The correction amount (ΔX and ΔY) of the ED chip 14 is calculated (Step S3).

The correction amount obtained from the image signal is compared with a preset reference value (step S4), and if it is determined that the correction amount is larger than the reference value, the flow advances to step S5 to perform correction. A movement correction corresponding to the amount is performed. Specifically, the movement of the correction amount △ Y is performed via the first motor 28, and the movement of the correction amount △ X is performed via the second motor 32.

On the other hand, if it is determined in step S4 that the correction amount is equal to or less than the reference value, the process proceeds to step S6, where the collet member 80 holds the LED chip 14 by suction. That is, the collet member 80 is
Is placed on the camera center of the imaging means 18 and then the fourth
Under the action of the motor 74, the elevator 78 descends. And
The collet member 80 provided on the lift 78 abuts the LED chip 14 positioned as described above, and the collet member 80 sucks the LED chip 14 under the action of a negative pressure source (not shown). . In addition, the fourth
When the motor 74 rotates in the opposite direction to that described above and the elevator 78 moves upward, the LED chip 14 moves up integrally with the collet member 80 (see FIG. 6).

Then, under the driving action of the moving mechanism 26, θ
After the stage 54 has been moved to the camera center of the imaging means 18 (step S7), the collet member 80 descends integrally with the elevator 78. For this reason, the LED chip 14 sucked and held by the collet member 80 is transferred onto the rotary table 58 constituting the θ stage 54 as shown in FIG. 7 (step S8). The collet member 80 is LE
After the suction of the D chip 14 is released, the LED chip 14 on the turntable 58 is moved upward by the CCD camera 86 constituting the image pickup means 18 while being moved up integrally with the lifting table 78.
Is imaged (step S9).

The captured image of the LED chip 14 is subjected to image processing by the image processing section 100, and the outer edge of the LED chip 14 is recognized, and the correction amount Δθ is calculated (step S10). This correction amount △ θ is compared with a preset reference value (step S11), and if it is determined that the correction amount △ θ is larger than the reference value, the process proceeds to step S12, where the correction amount △ θ corresponds to the correction amount △ θ. Then, the rotation of the turntable 58 is corrected.

After the correction by the θ stage 54 is completed, the frame 72 moves in the X-axis direction under the driving action of the third motor 66 constituting the driving means 62, and the probe 16 corresponds to the camera center of the imaging means 18. (Step S13). Further, under the action of the fourth motor 74, the lift 7
8 descends, and the contact 82 provided at the tip of the probe 16 contacts the LED chip 14 on the turntable 58 (see FIG. 8).

In this state, when a current power supply (not shown) is turned on, the LED chip 14 emits light (step S1).
4) The light emission center L0 of the LED chip 14 is imaged by the CCD camera 86 constituting the imaging means 18 (see step S15 and FIG. 9). The video signal from the CCD camera 86 is sent to the image processing unit 100, and the coordinates of the light emission center L0 are recognized. Next, after a current power source (not shown) is turned off, the image processing unit 100, as shown in FIG.
The coordinates (relative coordinates with respect to the light emission center L0) of the outer shape reference point L1 are calculated from the outer shape reference lines S1 and S2 (step S1).
6).

At this time, the fourth motor 74 constituting the driving means 62 is driven, the lift 78 is displaced upward, and the probe 16 is separated from the LED chip 14. Then the third
The motor 66 is driven to move the elevating table 78 integrally with the frame 72 in the arrow X direction, and the collet member 80 moves to the camera center of the imaging means 18 (step S17).
Then, the fourth motor 74 is driven to move the elevating table 78 downward, so that the collet member 80 abuts on the LED chip 14 on the rotary table 58, and under the action of a negative pressure generating source (not shown), The tip 14 is attracted to the collet member 80.

As shown in FIG. 11, the collet member 80
Moves upward together with the lifting table 78 under the action of the fourth motor 74 to suck and hold the LED chip 14 and take it out of the turntable 58 (step S18). further,
Proceeding to step S19, the bonding position on the substrate 12, which is sucked and held by the substrate suction table 56 under the driving action of the moving mechanism 26, is arranged at a position corresponding to the camera center of the imaging means 18.

Next, the collet member 80 that has attracted the LED chip 14 is lowered under the action of the fourth motor 74, and the collet member 80 is positioned at a height where the distance between the substrate 12 and the LED chip 14 is about 100 μm. The lowering is stopped (see step S20 and FIG. 12). In this state, for example, the CCD camera 8 constituting the imaging unit 18
8 captures an image of the LED chip 14 (step S2).
1).

Therefore, the outer reference lines S1 and S2 and the outer reference point L1 of the LED chip 14 are recognized, and as shown in FIG. 13, the light emission center L0 calculated from the outer reference point L1 and the bonding of the substrate 12 Correction amounts (ΔX and ΔY), which are positional deviation amounts from the position, are calculated (steps S22 and S23). Then, the process proceeds to step S24, and if it is determined that the correction amount is larger than the preset reference value, the process proceeds to step S25, where the bonding position on the substrate 12 is corrected.
The ED chip 14 is bonded (Step S2)
6).

On the other hand, if it is determined in step S24 that the correction amount is equal to or smaller than the reference value, the process similarly proceeds to step S26, where the LED chip 14 is bonded onto a silver paste provided on the substrate 12 in advance.

For the next LED chip 14 placed on the chip placement table 52, the same operation as described above is performed at step S.
Steps 2 to S18 are performed. And step S
In step 19, the substrate suction table 56 is moved at a constant pitch so that the distance from the LED chip 14 placed last time becomes a predetermined value.
After being moved in the axial direction, a new bonding position on the substrate 12 is set. Further, by performing the steps after step S20, the next LED chip 14 becomes:
Bonding is performed in a state where the pitch between the light emission center L0 and the LED chip 14 placed last time on the substrate 12 is aligned so as to be constant (see FIG. 14).

Similarly, a predetermined number of LED chips 14
Are sequentially bonded on the substrate 12 such that the pitch between the light emission centers L0 is constant. Next, the substrate 1
After the predetermined number of LED chips 14 are aligned on 2, in another process, the silver paste is heated and cured using, for example, an electric oven.

As described above, in the first embodiment, the substrate 1
The LED chip 14 before being bonded onto the LED 2 emits light through the probe 16 so that the LED chip 14 emits light.
The light emission center L0 of the chip 14 is recognized. Then, the coordinates of the outer shape reference point L1 of the LED chip 14 with respect to the recognized coordinates of the emission center L0 are recognized (calculated), and based on the coordinates of the outer shape reference point L1, the LED chip 14 is moved to the bonding position on the substrate 12. Is positioned.

Therefore, the light emitting center L0 of the LED chip 14 is reliably and securely positioned at a predetermined position on the substrate 12 without being affected by variations in the outer shape of the LED chip 14 and a shift in the position of the light emitting center L0. Positioning can be performed with high accuracy. Thus, the intervals between the light emission centers L0 are positioned at a constant pitch on the substrate 12, and, for example, a high-precision LE in which a plurality of LED chips 14 are bonded.
A D array is obtained, and by using this LED array, there is an effect that reading accuracy and writing accuracy are greatly improved.

In the above embodiment, the LED chips 14 are taken out one by one from the chip wafer 50,
Although the operation of bonding each LED chip 14 on the substrate 12 has been described, the LED chip 11 shown in FIG.
0 may be used. This LED chip 110
Constitutes a triple chip, and integrally includes collet suction chips 112a and 112b and a light emitting chip 114.

In the LED chip 110, while one light emitting chip 114 emits light, the other collet sucking chips 112a and 112b are sucked by the collet member 80 without emitting light. Therefore, the LED chip 110
Is used, the light emitting chip 114 can emit light in a state where the collet sucking chips 112a and 112b are sucked by the collet member 80 or the like on the θ stage 54. Accordingly, an effect is obtained in that it is possible to reliably prevent the occurrence of displacement when the LED chip 110 is sucked by the collet member 80.

In this embodiment, L is used as the light emitting element.
Although the ED chips 14 and 110 are used, the present invention is not limited to the LED, but can be applied to bonding of all the micro chip arrays which have a problem in the positional accuracy of the emission center. Further, the LED chip 110 has a triple chip structure, but may have a double chip structure or a chip structure having four or more chips.

[0042]

In the method and apparatus for bonding a light emitting element according to the present invention, the light emitting element is caused to emit light before bonding, the light emission center is recognized, and the outer reference point of the light emitting element corresponding to the light emission center is observed. While performing the bonding process. Therefore, the light emission center of each light emitting element can be easily and accurately positioned at a predetermined position on the substrate without being affected by variations in external dimensions. This makes it possible to efficiently obtain an array in which the distance between the light emission centers is set with high accuracy by a simple operation and configuration.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating a bonding apparatus for performing a light emitting element bonding method according to an embodiment of the present invention.

FIG. 2 is an explanatory side view of the bonding apparatus.

FIG. 3 is a first part of a flowchart describing a bonding method according to the present invention.

FIG. 4 is a middle part of the flowchart.

FIG. 5 is a latter part of the flowchart.

FIG. 6 is an explanatory front view of a state where the LED chip on the chip mounting table is suction-held.

FIG. 7 is an explanatory front view when the LED chips are arranged on a turntable.

FIG. 8 is an explanatory front view when the LED chips on the turntable emit light.

FIG. 9 is an explanatory diagram of a photographing screen showing a light emitting state of the LED chip.

FIG. 10 is an explanatory diagram of the light emission center and the coordinates of an external reference point.

FIG. 11 is an explanatory front view showing a state where the LED chip is sucked by a collet member.

FIG. 12 is an explanatory front view when positioning the LED chip with respect to a substrate.

FIG. 13 is an explanatory diagram of an imaging screen when aligning the LED chip and the substrate.

FIG. 14 is an explanatory front view when a second LED chip is aligned with a substrate.

FIG. 15 is an explanatory perspective view of an LED chip having a triple chip structure.

FIG. 16 is an explanatory perspective view of an LED array.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Bonding apparatus 12 ... Substrate 14, 110 ... LED chip 16 ... Probe 18 ... Imaging means 20 ... Light emitting element holding means 26 ... Moving mechanism 30, 34 ... Moving stage 50 ... Chip wafer 52 ... Chip placement table 54 ... Theta stage 56 ... Substrate suction table 62 ... Drive means 78 ... Elevating table 80 ... Collet members 86 and 88 ... CCD
Camera 90: bifocal optical system 100: image processing unit 112a, 112b, 114: chip

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Mino 210 Fuji Naka Photo Film Co., Ltd., Fuji Photo Film Co., Ltd. (Reference) 5F041 AA37 DA02 DA13 DA91 DB07

Claims (5)

[Claims] 1. A method of bonding a light emitting element to a predetermined position on a substrate, the method including the step of recognizing a light emitting center of the light emitting element by causing the light emitting element to emit light before bonding. Image-recognizing the coordinates of the outer reference point of the light-emitting element with respect to the coordinates of the recognized light-emitting center; and, based on the recognized outer reference point coordinates of the light-emitting element, moving the light-emitting element to a bonding position on the substrate. A method for bonding a light emitting element, comprising: positioning; and bonding the light emitting element to the substrate. 2. The bonding method according to claim 1, wherein a plurality of chips are connected to the light emitting element, and one of the chips is used as a light emitting chip, and the other chip is used as a light emitting element. A method for bonding a light emitting element, comprising a suction chip for holding. 3. A light emitting element bonding apparatus for bonding a light emitting element to a predetermined position on a substrate, comprising: a light emitting means for emitting the light emitting element before bonding; and a light emitting center of the light emitting element. Imaging means for image-recognizing the coordinates of the outer shape reference point of the light emitting element with respect to the coordinates of the recognized light emission center; and bonding the light emitting element on the substrate based on the recognized outer shape reference point coordinates. And a light emitting element holding means for positioning the light emitting element at a position. 4. A bonding apparatus according to claim 3, wherein said light emitting means for causing said light emitting element to emit light and said light emitting element holding means are provided with driving means capable of moving back and forth in a direction intersecting the optical axis direction of said imaging means. A bonding device for a light-emitting element, characterized in that: 5. The bonding apparatus according to claim 3, wherein a plurality of chips are connected to the light emitting element, and one of the chips is used as a light emitting chip and the other chip is used as the light emitting chip. A bonding device for a light-emitting element, which is a suction chip for holding the element.