JP2001007126A - Device and method for positioning head and work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve positioning accuracy by calculating an amount of relative position deviation between a head and a work from the recognition result of first and second optical recognition means and instructing the drive mechanism of each axis of the head and work to move based on the operation results. SOLUTION: Two CCD cameras 31 that become a second optical system recognition means are arranged so that they overlap each other back and forth at the upper portion of a wafer-positioning position 8. The CCD cameras 31 can be moved in a direction in parallel with a work drive mechanism 4 by a motor 33. Then, the amount of relative position deviation is calculated from the recognition result of an alignment mark 17 of the head according to CCD cameras 23 and 23' that become the first optical system recognition means and the posture of the work according to each CCD camera 31 by an arithmetic unit. Based on the operation result, an instruction is given to the drive mechanism of each axis of the head and work to move or rotate, thus improving the positioning accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a head and work positioning apparatus and a positioning method used in a ball mounting apparatus for mounting solder balls and solder bumps on a wafer or a substrate.

[0002]

2. Description of the Related Art In a conventional solder ball mounting apparatus, positioning is performed by fixing the posture of a mount head or a flux transfer head and adjusting the posture of a work to the posture of the head. For this reason, there is no posture recognition means on the head side, and only the posture recognition means for the work exists. However, due to the recent trend toward fine balls and the mass loading of large numbers of balls, the required positioning accuracy has dramatically increased, and mounting quality cannot be secured by recognizing the position of the head and work using conventional methods. Have been.

[0003]

In order to solve the above-mentioned problems, the present invention provides alignment marks for positioning on the head side, recognizes both the attitude of the head and the attitude of the work, and recognizes both. It is an object of the present invention to provide a ball mounting device provided with a positioning device and a positioning method capable of responding to a demand for high positioning accuracy due to a flow of miniaturized balls and a batch mounting of a large number of balls by performing positioning from a result.

[0004]

According to the present invention, to solve the above-mentioned problems, a head provided with an alignment mark, first optical system recognizing means for recognizing the alignment mark, and recognizing a posture of a workpiece. A second optical system recognizing means, a calculating means for calculating a relative displacement between the head and the work from a recognition result of the first optical system recognizing means and the second optical system recognizing means, and a result of the calculating means. The present invention provides a head and work positioning device in a ball mount device, characterized by having control means for instructing a drive mechanism for each axis of the head and the work to move.

The second invention is substantially the same as the first invention, wherein the first optical system recognizing means includes a head provided on a stage for moving and positioning the work and a positioning of the work. Provide equipment.

According to a third aspect of the present invention, an alignment mark provided on a head is recognized by a first optical system recognizing means, and a posture of a work is recognized by a second optical system recognizing means. And calculating the relative displacement between the head and the work by the calculating means from the recognition result of the second optical system recognizing means,
A method for positioning a head and a work in a ball mount device, wherein the head and the work are positioned by instructing movement of a drive mechanism for each axis of the head and the work from the control means based on a result of the arithmetic means. .

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a solder ball mounting apparatus according to the present invention. The solder ball mounting device includes: a wafer supply unit 1;
It comprises a flux transfer section 2, a ball mount section 3, and a work drive mechanism 4.

The work in this embodiment is a wafer,
The wafer supply unit 1 includes a wafer cassette 5 for supply, a wafer cassette 6 for unloading, a wafer cassette 7 for defect, a scalar robot 9 for clean room for transferring wafers, and a work drive. This is the wafer positioning position 8 on the mechanism 4.

As shown in FIG. 2, above the wafer positioning position 8, two CCD cameras 31 as second optical system recognizing means in the present invention are arranged so as to overlap one another in the drawing. In the drawing, only the front one is shown), and below it, the illuminator 32 facing the wafer
Has been deployed. The CCD camera 31 is movable by a motor 33 in a direction parallel to the work drive mechanism 4 (X-axis direction) above the wafer positioning position 8 on the work drive mechanism 4.

The work drive mechanism 4 includes a wafer stage 3
0 is provided, and a two-axis drive mechanism for driving the wafer stage 30 is provided, that is, an X-axis (left-right direction in FIG. 1) and a Θ-axis (rotation direction). The Θ-axis drive mechanism is a drive mechanism whose main role is positioning, while the X-axis drive mechanism has a role of moving the work and a role of positioning.

The wafer stage 30 is moved by an X-axis driving mechanism to a wafer positioning position 8 and a flux transfer position 11.
And the movement between the ball mounting positions 20 can be stopped. In the embodiment, the head according to the present invention includes a flux transfer head 13 and a solder ball mount head 25.
And The transfer head 13 is provided on the wafer stage 30.
And two CCD cameras 23, 23 'for observing the mount head 25. The CCD camera 2
Reference numerals 3 and 23 'serve as first optical system recognition means in the present invention.

The ball mounting device according to the present embodiment has a work attitude and a CCD
An arithmetic unit (not shown) for calculating the relative displacement from the recognition result of the head alignment mark 17 by the cameras 23 and 23 ', and each axis (Y axis, X axis) of the head and the work based on the result of the arithmetic unit. And a control device (not shown) for instructing movement or rotation to the drive mechanism of the (axis, Θ axis).

The flux transfer section 2 includes a transfer head 13 and a drive mechanism thereof, a flux supply device 10, and a flux transfer position 11 on a work drive mechanism 4. A part 12 is provided.

As shown in FIG. 5, alignment marks (positioning marks) are formed on the lower surface 40 of the transfer head 13 at four positions outside the vicinity of the contour of the wafer.
17 are provided. The alignment mark 17 is 1
It is formed with a 0.3 mm diameter recess provided at the center of a 0 mm diameter projection. The projections are made of the same material and process as the flux transfer projections 18. The alignment mark 17 ′ may be formed at a position where the flux transfer projection 18 does not exist at a position inside the vicinity of the wafer contour on the head lower surface 40 of the transfer head 13.

Transfer head 13 of flux supply device 10
As shown in FIG. 3, the flux supply device 10
There is provided a two-axis drive mechanism of a Y-axis and a Z-axis (elevation axis) which reciprocate between the flux transfer position 11 on the work drive mechanism 4 and the flux transfer position 11. In the figure, reference numeral 34 denotes a Z-axis drive motor of the transfer head 13, and reference numeral 34 'denotes a Y-axis drive motor. The Y-axis driving mechanism here is used for positioning the transfer head 13 and the work together with the role of the transfer head 13 to move.

The flux supply device 10 is provided with a flat flux leveling section, and the squeegee 15 can level the flux to a constant thickness. A flux supply section 16 corresponding to the flux transfer area of the transfer head 13 is formed in the flux leveling section.

The ball mounting section 3 includes a mounting head 2
5 and its driving mechanism, a ball supply device 19, a ball mounting position 20 on the work driving mechanism 4, an excess ball removing device 21 disposed therebetween, a ball suction error inspection device, and a ball suction error inspection device. And a ball discharge device 24 that enters below the mount head 25 when an excess ball is detected.

As shown in FIGS. 6 and 7, alignment marks 17 'are provided on the lower surface 41 of the mount head 25 at four positions outside the vicinity of the contour of the wafer where the suction holes 26 do not exist. . The alignment mark 17 'is formed by a recess having a diameter of 0.3 mm. Note that the alignment mark 17 ′ may be formed at a position where the suction hole 26 does not exist at a position inside the vicinity of the contour of the wafer on the head lower surface 41 of the mount head 25.

The ball supply device 19 is configured as a parts feeder, and a vibrator is attached to a ball tray 27 that supplies solder balls to the mount head 25. The vibration of the vibrator causes the solder ball to jump up obliquely upward, and when viewed from above, the solder ball moves around the inside of the ball tray 27.

Above the ball tray 27, a supply port 28 for supplying solder balls from the ball stocker (not shown) into the ball tray 27 is arranged so as to be able to advance and retreat.
A sensor 29 for detecting the remaining amount of the ball in the ball tray 27 is attached to the tip of the supply port 28, and when a shortage of the remaining amount of the ball is detected, a fixed amount of the solder ball is supplied from the ball stocker. The supply port 28 has a structure in which the mount head 25 is evacuated to the outside of the ball tray 27 to avoid interference when the solder ball is attracted by the mount head 25.

The surplus ball removing device 21 is a removal nozzle for removing excess balls adsorbed on the mount head 25.

As shown in FIG. 4, the mount head 25 has a Y-axis reciprocating between the ball supply device 19 and a ball mount position 20 on the work drive mechanism 4, and a Z-axis (elevation axis). A drive mechanism for the shaft is provided. In the figure, reference numeral 35 denotes a Z-axis drive motor, and reference numeral 35 'denotes a Y-axis drive motor. The Y-axis driving mechanism here is used for positioning the mount head 25 and the work together with the role of the movement of the mount head 25.

The ball suction error inspection apparatus detects a suction error such as a missing ball or an extra ball (excess ball) and a remaining ball which is a mounting error by using four line CCD cameras 22 and 22 '.

Hereinafter, an operation procedure of the solder ball mounting apparatus according to the present embodiment will be described. First, the robot 9 supplies wafers one by one from the supply wafer cassette 5 onto the wafer stage 30 at the wafer positioning position 8. When a wafer is supplied, the wafer stage 30 starts vacuum suction through a hole on the upper surface of the wafer stage 30 through a blower motor (not shown) to hold the wafer.

The held wafer is extracted by extracting a positioning mark or a circuit pattern formed on the wafer surface by two CCD cameras 31 which are second optical system recognition means disposed above the wafer positioning position 8. recognize. When the position of the wafer on the wafer stage 30 is recognized, data is sent to an arithmetic unit (not shown). The wafer stage 30 for which the wafer position recognition has been completed is sent to the flux transfer position 11. At this time, it stops at a position that takes into account the displacement of the X axis stored at the time of wafer positioning.

Next, in the flux supply device 10, the flux surface is leveled by the squeegee 15,
When the transfer head 13 comes into contact with the flux supply unit 16 and a load of a predetermined pressure or more is applied, it is determined that the supply of the flux has ended, and the lowering of the transfer head 13 is stopped.
To rise.

Thereafter, the wafer is moved to the flux transfer position 11, and the alignment marks 17 on the lower surface 40 of the transfer head 13 are moved by the two CCD cameras 23 and 23 'which are the first optical system recognition means provided on the wafer stage 30. Recognize. The arithmetic unit adds the position data of the previously recognized wafer to the recognition result, and calculates a relative positional deviation amount from the recognition results of the two.

In response to the result of this calculation, the control device controls one axis (Y-axis) of the transfer head 13 and two axes (X-axis) of the wafer stage 30.
(The axis and the Θ axis), a command to align the position of the wafer and the transfer head 13 is issued. Based on this, the Y-axis of the transfer head 13 and the X-axis and Θ-axis of the wafer stage 30 operate to perform the alignment.

After the alignment, the transfer head 13 is lowered, and when the load on the Z-axis drive motor 34 of the transfer head 13 reaches a certain value, it is determined that the transfer is completed.
To rise. After ascending, the transfer head 13 returns to the flux supply device 10, and the wafer stage 30 moves to the ball mounting position 20.

On the other hand, the mount head 25 descends from above the ball supply device 19 and stops at a specified position, and applies a suction force from a blower motor (not shown) to the mount head 25 to attract the solder balls to the lower surface of the mount head 25. It is adsorbed in the hole 26. When the internal pressure of the mount head 25 becomes lower than the predetermined pressure, it is determined that the suction is completed, and the mount head 25 is raised. Then the surplus ball removal device 2
In step 1, the surplus balls are removed, and the apparatus moves to a ball suction error inspection device.

If there is a ball suction error, if the ball is a missing ball, the ball is moved to the ball supply device 19 again and the suction operation is repeated. If there is an excess ball, the ball discharge device 24 enters below the mount head 25, discharges all the suction balls into the ball discharge device 24, moves to the ball supply device 19 again, and repeats the suction operation.

If there is no abnormality, the operation moves to the ball mounting position 20. At the ball mount position 20, the alignment marks 17 'on the head lower surface 41 of the mount head 25 are recognized by the CCD cameras 23 and 23' as first optical system recognition means provided on the wafer stage 30. The arithmetic unit adds the position data of the previously recognized wafer to the recognition result, and calculates a relative positional deviation amount from the recognition results of the two.

In response to the calculation result, the control device issues a command for aligning the position of the wafer and the mount head 25 with respect to one axis (Y axis) of the mount head 25 and two axes (X axis, Θ axis) of the wafer stage 30. Put out. Based on this, the Y axis of the mount head 25 and the X axis and Θ axis of the wafer stage 30 operate to perform positioning. Mount head 2 after positioning
5 goes down, mounts the solder balls on the wafer at the ball mounting position 20, and then goes up.

After the mounting of the solder balls is completed, the wafer stage 30 returns to the wafer positioning position 8, but the mounting state of the solder balls on the wafer is inspected by the CCD camera 31 previously moved to the ball mounting inspection position. The main purpose of the CCD camera 31 is to recognize the posture of the work as the second optical system recognition means. In the embodiment, the CCD camera 31 also has a role of inspecting the mounting state of the solder balls on the wafer.

At the time of inspection of the mounting state, the CCD camera 31 is stopped, and the entire surface is scanned by the CCD camera 31 by moving the wafer stage 30. As a result of the inspection, if the mount is good, the robot 9 inserts it into the unloading wafer cassette 6 if the mount is not good, and into the defective wafer cassette 7 if the mount is bad.

[0036]

According to the present invention, a head provided with an alignment mark, first optical system recognizing means for recognizing the alignment mark, second optical system recognizing means for recognizing the posture of the work, and both recognizing means. Calculating means for calculating the relative displacement between the head and the work from the result of recognition of the head, and control means for instructing the drive mechanism of each axis of the head and the work to move based on the result of the calculating means. Since the apparatus and the positioning method are used, it is possible to meet the demand for high positioning accuracy due to the flow of fine balls and the simultaneous mounting of a large number of balls.

According to the second aspect of the present invention, the first optical system recognizing means is provided on a stage for moving and positioning the work, so that the head driving mechanism is utilized by utilizing the work driving mechanism. Since the mark can be recognized, the transfer head and the mount head can be recognized with a small number of drive mechanisms, and the overall size of the ball mounting device can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a solder ball mounting device.

FIG. 2 is an explanatory view showing a CCD camera for inspection at a wafer positioning position.

FIG. 3 is a side view of a flux transfer unit.

FIG. 4 is a side view of a ball mount unit.

FIG. 5 is an explanatory sectional view showing the lower surface of the transfer head.

FIG. 6 is an explanatory sectional view showing the lower surface of the mount head.

FIG. 7 is an explanatory view showing an alignment mark on the lower surface of the mount head.

[Explanation of symbols]

 1. . . . . . . . 1. Wafer supply unit . . . . . . . Flux transfer unit 3. . . . . . . . Ball mount part 4. . . . . . . . Work drive mechanism 5, 6, 7. . . . 7. Wafer cassette . . . . . . . 8. Wafer positioning position . . . . . . . Robot 10. . . . . . . Flux supply device 11. . . . . . . 11. Flux transfer position . . . . . . Cleaning unit 13. . . . . . . Transfer head 15. . . . . . . Squeegee 16. . . . . . . Flux supply unit 17, 17 '. . . Alignment mark 18. . . . . . . Transfer projection 19. . . . . . . Ball supply device 20. . . . . . . Ball mount position 21. . . . . . . Excess ball removing device 22, 22 ', 23, 23', 31. . . CCD camera 24. . . . . . . Ball discharge device 25. . . . . . . Mount head 26. . . . . . . Adsorption hole 27. . . . . . . Ball tray 28. . . . . . . Supply port 29. . . . . . . Sensor 30. . . . . . . Wafer stage 32. . . . . . . Illuminators 33, 34, 34 ', 35, 35'. . . Motor 40, 41. . . . Head lower surface

Claims (3)

[Claims] 1. A head provided with an alignment mark, a first optical system recognizing means for recognizing the alignment mark, a second optical system recognizing means for recognizing a posture of a work, and a first optical system recognizing means. Calculating means for calculating the relative displacement between the head and the work from the recognition result of the means and the second optical system recognizing means, and instructing the drive mechanism of each axis of the head and the work to move based on the result of the calculating means A positioning device for a head and a work in a ball mount device, comprising a control means. 2. The apparatus according to claim 1, wherein the first optical system recognizing means is provided on a stage for moving and positioning the work. A first optical system recognizing means for recognizing an alignment mark provided on the head, a work posture of the head being recognizable by the second optical system recognizing means;
The relative displacement between the head and the work is calculated by the calculating means from the recognition result with the optical system recognizing means. And positioning the head and the work in the ball mount device.