JP2002111289A - Apparatus for supplying chip and method for mounting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for supplying a chip capable of mounting the chip of a wafer by surely picking up the chip and mounting the chip on a work and a method for mounting. SOLUTION: The apparatus for supplying the chip comprises a die ejector 20 for lifting the chip 4 of the wafer 1 from below, a wafer recognition camera 23 installed above the ejector 20 by bringing an optical axis into coincidence with a central position of pin 22 projected from the ejector 20, an X-Y table 7 for horizontally moving a wafer holder 3 for holding the wafer 1 in an X-Y direction, and a θ table 10 for supporting the table 7 from below. In this case, a rotating center of the table 10 is brought into coincidence with the optical axis of the camera 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip supplying apparatus and a mounting method for supplying chips to a nozzle by pushing up chips on a wafer by a die ejector.

[0002]

2. Description of the Related Art Chips of a wafer stuck on a wafer sheet are pushed up from below by pins of a die ejector, vacuum-adsorbed to a nozzle, picked up, and mounted on a work such as a printed circuit board or a lead frame. You. In this case, before the nozzle picks up the chip, the position of the chip is recognized and the position is corrected. Conventionally, chip position recognition and position shift correction have been performed as follows.

A θ table (horizontal rotary table) is placed on an XY table, and a wafer holder for holding a wafer sheet is supported on the θ table. Then, an image of a chip on a wafer sheet to be picked up is captured by a camera, and a positional shift of the chip in the XYθ direction is detected.
The displacement in the X and Y directions is corrected by driving the XY table to horizontally move the wafer in the X and Y directions, and the displacement in the θ direction (horizontal rotation direction) is corrected by driving the θ table. I do. The nozzle whose positional deviation has been corrected in this way is picked up by the nozzle and mounted on the work.

[0004]

However, in the conventional chip supply device, when the XY table is used to correct the XY-direction positional deviation and the θ-table is used to correct the θ-directional positional deviation, the θ rotation of the θ table becomes impossible. As a result, a new positional shift occurs in the chip in the X and Y directions. this is,
Since the θ table was set on the XY table,
When the wafer is moved in the X and Y directions by the Y table, θ
This is because the rotation center of the wafer in the correction moves. Although the new positional deviation amounts in the X and Y directions are very small, chip sizes have been increasingly miniaturized in recent years, so even small positional deviations may cause frequent pickup errors. I have.

Therefore, conventionally, the above-mentioned new positional deviation amount in the X and Y directions is obtained by mathematical calculation and corrected. However, this calculation is rather troublesome, and every time a large number of chips on a wafer sheet are picked up, the calculation must be repeated.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a chip supplying apparatus and a mounting method capable of reliably picking up a chip on a wafer and mounting the chip on a work.

[0007]

According to the present invention, there is provided a die ejector for pushing up a chip of a wafer from below, and an optical axis is set above the die ejector so as to coincide with a center position of a pin projecting from the die ejector. A camera for recognizing a wafer, an XY table for horizontally moving a wafer holder for holding the wafer in the XY directions, and a θ table for supporting the XY table from below, the center of rotation of which coincides with the optical axis of the camera. It is a chip supply device characterized by having been performed.

The present invention also provides a chip mounting method using the chip supply device according to claim 1, wherein the XY
A step of matching the directions of the coordinate system of the table and the coordinate system of the camera; a step of driving the XY table to move a chip to be picked up on the optical axis of the camera; Capture the image of the chip,
Determining a position shift of the chip in the XYθ direction, and correcting the position shift in the XYθ direction, picking up the chip by the nozzle, and mounting the chip on a work positioned by a positioning device. This is a chip mounting method.

According to another aspect of the present invention, there is provided a chip mounting method using the chip supply device according to claim 1, wherein the XY
Driving a table to temporarily position a chip to be picked up above the die ejector; capturing an image of the chip with the camera;
Calculating a position shift in the direction, calculating a chip position shift by a calculation unit, and driving the XY table and the θ table to correct the position shift in accordance with the result calculated in the step. And a step of picking up the chip by the nozzle and mounting the chip on a work positioned by a positioning device.

[0010]

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a chip mounting device according to the first embodiment of the present invention, FIG. 2 is a plan view of a chip supply device according to the first embodiment of the present invention, and FIG. 3 is a chip according to the first embodiment of the present invention. FIG. 4 is a block diagram of a control system of the chip supply device according to the first embodiment of the present invention, and FIGS. 5, 6, 7, and 8 are chips according to the first embodiment of the present invention. FIG. 4 is a partial plan view of a chip supply device for explaining the pickup operation of FIG.

In FIG. 1, the chip mounting device comprises a chip supply device A and a work positioning device B. First, the chip supply device A will be described. 1 to 3, a wafer sheet 2 to which a wafer 1 is attached is held by a wafer holder 3. A large number of chips 4 to be the wafer 1 are adhered to the wafer sheet 2.

5 is an X table and 6 is a Y table.
The X table 5 and the Y table 6 are stacked to form an XY table 7, and the wafer holder 3 is supported by a bracket 8 on the Y table 6. MX is an X-axis motor that drives the X table 5, and MY is Y that drives the Y table 6.
It is a shaft motor.

The X table 5 is set on the θ table 10. table 10 is set on fixed table 9. A plurality of arc-shaped guide rails 11 are provided on the fixed table 9 (in the present embodiment, four at the positions corresponding to the four corners of the θ table 10 as shown in FIG. 2).
A slider 12 is provided on the lower surface of the θ table 10 to be slidably fitted on the guide rail 11.

In FIG. 1, a bracket 13 is provided on the fixed table 9,
A motor Mθ is provided. motor Mθ is gear 14
To rotate. The gear 14 is engaged with an arc gear 15 provided on the θ table 10. Therefore, when the θ motor Mθ is driven and the gear 14 rotates, the θ table 1
The XY table and the like on the 0 and θ tables 10 rotate θ.

In FIG. 1, the planar shape of the θ table 10 is a U-shape, and the fixed table 9 at the concave portion thereof is formed.
A die ejector 20 is provided on the upper side. The position of the ejector 20 can be adjusted, but the ejector 20 is fixed and does not move during operation of the apparatus. From the pepper pot 21 of the die ejector 20, the wafer sheet 2
A pin 22 for pushing up the upper chip 4 from below is freely projectable. The number of pins 22 is changed according to the chip size and the like.

Above the wafer 1, a camera 23 for wafer recognition is provided. The rotation center of the θ table 10, the center of the pepper pot 21, and the optical axis of the camera 23 are set on the same vertical line NA. In the case where the number of pins 22 of the pepper pot 21 is one, this pin 22 is the center, but when there are a plurality of pins 22, the center of the plurality of pins 22 is the center of the whole. The camera 23 may be arranged such that the center of rotation of the θ table is located within the field of view, but it is more likely that the optical axis of the camera coincides with the center of rotation of the θ table 10 as in this embodiment. The calculation for obtaining the correction amount does not have to be complicated.

Next, the work positioning device B will be described. In FIG. 1, 31, 32, and 33 are guide rails of the substrate 30. A movable table 34 is provided below the center guide rail 32. Movable table 34
Is composed of an X table 35 and a Y table 36, and positions the substrate 30 on the movable table 34 in the X and Y directions. Reference numeral 37 denotes a bond applicator, which applies the bond of the bond plate 38 to a predetermined position of the substrate 30 positioned by the positioning device B. Reference numeral 39 denotes a transfer head, which picks up the chips 4 of the wafer 1 by suctioning them to the nozzles 40 and mounts them on the bond applied to the substrate 30. The bond applicator 37 and the transfer head 39 are moved in a horizontal direction by a moving table (not shown). Reference numeral 41 denotes a board recognition camera for observing the board 1 from above.

In FIG. 4, the wafer recognition camera 23 is connected to a control unit 50 via a position recognition unit 51.
X-axis motor MX, Y-axis motor MY, θ motor Mθ
Are also connected to the control unit 5 via the driving units 52, 53 and 54, respectively.
Connected to 0. The control unit 50 controls the entire apparatus,
Register necessary data and perform various calculations.

This chip mounting apparatus has the above-described configuration. Next, a chip mounting method will be described. First, a method of supplying chips will be described. 5 to 8 show the chip supply method by the chip supply device A in order. First, by driving the θ motor Mθ to rotate the θ table 10 and the XY table 7 on the θ table 10 by θ, the coordinate systems X1, Y1 of the XY table 7 and the coordinate systems X2, Y2 of the wafer recognition camera 23 are changed. Match the orientation. FIG. 5 shows a state in which they are matched, and as shown, the X coordinate axes X1 and X2 and the Y coordinate axes Y1 and Y2 are parallel to each other. Needless to say, the X coordinate axis X1 coincides with the moving direction of the X table 5, and the Y coordinate axis Y1 coincides with the moving direction of the Y table 6. In the figure, C
Is the field of view of the camera 23. Here, as described above,
The rotation center of the θ table 10, the center of the pepper pot 21, and the optical axis of the camera 23 are set on the same vertical line NA.

Next, the X table 5 and the Y table 6 are driven to horizontally move the wafer 1 in the X direction and the Y direction (see the arrow A in FIG. 5), and the chips 4 to be picked up are pinned by the die ejector 20. Above 22 (on the vertical line NA)
That is, it is provisionally positioned at the observation position by the camera 23.
FIG. 6 shows this state. Next, the image of the chip 4 is captured by the camera 23, and the position (a, b) and the inclination θ of the center of the chip 4 on the coordinate system are obtained by the position recognition unit 51 (see FIG. 7). A, b, and θ are the amounts of displacement of the chip 4 in the X, Y, and θ directions.

Next, in FIG. 8, the X table 5 and the Y table 6 are driven to horizontally move the chip 4, thereby correcting the X direction displacement a and the Y direction displacement b. By driving and rotating θ, θ
Compensate the positional deviation in the direction. In this case, the center of the chip 4 and the center (center of rotation) of the θ table 10 are on the same vertical line NA and coincide with each other.
Is rotated to correct the displacement in the θ direction, the new X
No displacement occurs in the direction or the Y direction. In addition, since the directions of the coordinate system of the XY table 7 are matched before the positional deviation is obtained, the calculated positional deviations a, b, and θ of the chip can be used as the correction movement amounts ΔX, ΔY, Δθ.

After the displacement of the chip 4 to be picked up next is corrected as described above, the chip 4 is pushed up by the pins 22 of the die ejector 20, vacuum-adsorbed to the nozzle 40 and picked up. Transfer to 30. Prior to this, a bond is previously applied to the mounting position of the chip 4 on the substrate 30 by the bond applicator 37. The above operation is sequentially performed on the chips 4 of the wafer 1, and the chips 4 are sequentially mounted on the substrate 30.

(Embodiment 2) FIG. 9 is a partial plan view of a chip supply device according to Embodiment 2 of the present invention, and FIG. 10 is an explanatory diagram of correction of chip misalignment in Embodiment 2 of the present invention. . In the first embodiment, the method of correcting the position shift of the chip by matching the direction of the coordinate system of the XY table with the direction of the coordinate system of the camera has been described. A method of correcting will be described.

In FIG. 9, the XY table and the camera 23
The X coordinate axes X1 and X2 and the Y coordinate axes Y1 and Y2 do not match (are not parallel to each other). FIG.
Is an enlarged view of FIG. 9, and O ₁ is the origin of the coordinates of the XY table. O ₂ is the origin of the coordinate system of the camera 23 and coincides with the rotation center NA of the θ table 10. The a, b, θ is displaced position in XYθ direction of the chip 4 in the coordinate system of the camera 23, xO, yO rotation center of the coordinate system the coordinates i.e. theta table 10 the origin O ₂ of the camera 23 in the coordinate system of the XY table Are coordinates. r is the same θ
It is the inclination of the direction. The angle at which X1 and X2 become parallel is 0 °, and the counterclockwise rotation direction of the θ table 10 is positive.
xa and yb are the coordinates of the chip 4 in the coordinate system of the XY table, and the above are known values obtained from the observation result of the chip 4. In FIG. 10, α is the rotation angle of the chip 4 in the coordinate system of the camera 23, and α is obtained by the calculation of (Equation 1).

[0025]

(Equation 1)

Next, the processing procedure will be described. First, the chip 4 to be picked up is temporarily positioned above the die ejector 20. Next, the image of the chip 4 is captured by the camera 23, and the position (a, b) of the chip 4 is detected by the position recognition unit 51.
And the inclination θ.

Next, the corrected movement amounts Δx, Δy, Δθ are calculated using (Equation 2).

[0028]

(Equation 2)

In accordance with the calculation result of (Equation 2), the X table 5, the Y table 6, and the θ table 10 are driven by the respective correction movement amounts to correct the position shift, and the first embodiment is performed.
Similarly, the chip 4 is transferred and mounted on the substrate 30.

[0030]

As described above, according to the present invention, it is possible to realize a chip supplying apparatus and a mounting method capable of reliably picking up a chip on a wafer and mounting the chip on a work.

[Brief description of the drawings]

FIG. 1 is a perspective view of a chip mounting device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a chip supply device according to the first embodiment of the present invention.

FIG. 3 is a side view of the chip supply device according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a control system of the chip supply device according to the first embodiment of the present invention.

FIG. 5 is a partial plan view of a chip supply device for describing a chip pickup operation according to the first embodiment of the present invention.

FIG. 6 is a partial plan view of a chip supply device for describing a chip pickup operation according to the first embodiment of the present invention.

FIG. 7 is a partial plan view of a chip supply device for describing a chip pickup operation according to the first embodiment of the present invention;

FIG. 8 is a partial plan view of the chip supply device for describing a chip pickup operation according to the first embodiment of the present invention.

FIG. 9 is a partial plan view of a chip supply device according to a second embodiment of the present invention.

FIG. 10 is an explanatory diagram of correction of a chip position shift according to the second embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 1 wafer 3 wafer holder 4 chip 7 XY table 10 θ table 20 die ejector 22 pin 23 camera

Claims (3)

[Claims] A die ejector for pushing up a chip of a wafer from below; a wafer recognition camera installed above the die ejector with an optical axis aligned with a center position of a pin projecting from the die ejector; An XY table for horizontally moving the wafer holder holding the XY table in the XY directions, and a θ table for supporting the XY table from below, wherein the center of rotation of the θ table is located within the field of view of the camera. Chip supply device. 2. A method of mounting a chip using the chip supply device according to claim 1, wherein: the directions of the coordinate system of the XY table and the coordinate system of the camera are matched; Driving a table to move a chip to be picked up on the optical axis of the camera; capturing an image of the chip with the camera to determine a displacement of the chip in the XYθ direction; Correcting the positional deviation of the chip, picking up the chip by the nozzle, and mounting the chip on a work positioned by a positioning device. 3. A chip mounting method using the chip supply device according to claim 1, wherein the XY table is driven to temporarily position a chip to be picked up above the die ejector. Capturing the image of the chip with the camera, and XY of the chip
a step of calculating a position shift in the θ direction; a step of calculating a correction movement amount for correcting a chip position shift based on the rotation angle of the θ table and the position shift in the XYθ direction; and a correction movement amount calculated in the step. According to the X
A step of driving the Y table and the θ table to correct the displacement, and a step of picking up the chip by the nozzle and mounting the chip on a work positioned by a positioning device. Implementation method.