JP2765495B2 - Die bonder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonder, and more particularly, to a die bonder used in the manufacture of semiconductor devices, which selects a specified semiconductor chip from a semiconductor wafer mounted on an XY table, picks it up, and mounts it.

[0002]

2. Description of the Related Art For example, a semiconductor device is generally manufactured collectively from a semiconductor wafer on which a large number of semiconductor elements are formed. In the manufacture of this semiconductor device, a predetermined process is performed in a state where the semiconductor wafer is attached to the adhesive sheet. For example, after checking the characteristics of each semiconductor element of a semiconductor wafer, not only the quality of the semiconductor element but also the quality of the semiconductor element is ranked. Thereafter, the semiconductor wafer is divided into individual semiconductor elements by dicing, and the semiconductor wafer divided into a large number of semiconductor chips is set on a die bonder while being adhered to the adhesive sheet.

As shown in FIGS. 3 and 4, this die bonder has a large number of semiconductor chips 1 (hereinafter simply referred to as chips).
A semiconductor wafer 2 (hereinafter, simply referred to as a wafer) divided into a plurality of pieces is attached to an adhesive sheet 3, and the adhesive sheet 3 is mounted with a wafer ring 4 stretched over a ring-shaped frame, and a pulse motor 5x XY table 6 driven by a driving source, a camera 7 disposed above the XY table 6 for picking up an image of each chip 1 of the wafer ring 4 for image recognition, and holding the chip 1 of the wafer ring 4 by suction. And a suction collet 8 for picking up, transferring, and mounting to a predetermined position such as a lead frame.

In the die bonder, when the wafer ring 4 is set on the XY table 6, the chips 1 of the wafer ring 4 are first moved by driving the pulse motors 5x and 5y at a constant pitch. Sensing is performed while the camera 7 recognizes an image.

[0005] The sensing of the chip 1 is performed by the wafer 2
This is performed based on the rank-specific data of good products obtained at the time of the characteristic check, and the desired chips 1 are sequentially arranged at positions corresponding to the suction collet 8 by moving the XY table 6 and picked up by the suction collet 8. . In this way, good chips 1 are picked up by rank, transferred to a lead frame or the like, and mounted.

[0006]

As described above, the pickup of the chip 1 is performed in a relationship corresponding to the rank assigned to the chip 1. Therefore, when sensing the chip 1, the pulse motor 5
By moving the XY table 6 at a constant pitch by driving x and 5y, the chip 1 of the rank to be picked up
Must be accurately positioned and positioned at the pickup position. For that purpose, it is necessary to reliably sense the chip 1 of the rank to be picked up.

However, in the case of the pulse motors 5x and 5y used as the driving source of the XY table 6, the motor step-out easily occurs, and the chip 1 of the rank to be picked up due to the displacement caused by the motor step-out is surely sensed. It was sometimes difficult to do so.

When the pulse motor drive is set at a low speed, motor out-of-step does not occur, but the index decreases. In addition, instead of picking up the chip 1 in a relationship corresponding to the rank given to the chip 1 as described above, when picking up the chip 1 while simply recognizing the image, if the sensing is reliably performed, several pulses may be used. The degree of step-out was not a problem.

For this reason, as means for preventing the displacement due to the motor out-of-step, a servo motor may be used as a drive source of the XY table 6. However, when a servo motor is used, the above-described motor disconnection is required. Although there is an advantage that positional deviation due to tone can be avoided, there are the following problems.

In general, the resolution of a servomotor per rotation is several steps higher than that of a pulse motor, and the servomotor operates at the device speed unless an electric circuit such as an LSI for high pulse oscillation (servomotor) is used. In addition, it is necessary to change not only the servo mechanism but also its peripheral circuits, resulting in an expensive system as a whole.

On the other hand, the pulse motor conventionally used has a low rotating ability, and the pulse oscillating section needs a low-speed circuit as compared with the servomotor. In addition, when die bonding is performed for each chip rank, it is not necessary that only the XY table have a very high speed. vice versa,
Speeding up by the servo system did not directly increase the speed as a system due to the vibration of the XY table, and lacked the balance of the system.

Accordingly, the present invention has been proposed in view of the above problems, and its object is to prevent displacement of the motor due to step-out and to change existing equipment at a minimum cost to reduce the cost. A die bonder is provided.

[0013]

As a technical means for achieving the above object, the present invention provides a method in which a wafer is mounted on an XY table in a state where the wafer is attached to a sheet, and the XY table is pulsed based on a command pulse. XY by motor drive
In the die bonder, the chips constituting the wafer are sensed, picked up from a sheet, and mounted by moving at a constant pitch in the direction.
An encoder is attached to the pulse motor that drives the table, a feedback pulse output from the encoder is counted by a counter, and based on a comparison between the actual drive pulse output from the counter and the command pulse given to the pulse motor. The sensing is performed while correcting the position coordinates of the XY table.

Further, according to the present invention, a difference between a feedback pulse output from the encoder and a command pulse is counted by a deviation counter, and the position coordinates of an XY table are corrected based on the deviation pulse output from the deviation counter. Sensing is also possible.

[0015]

In the die bonder according to the present invention, an encoder is attached to the XY table, a feedback pulse output from the encoder is counted by a counter, and an actual drive pulse output from the counter and a command pulse applied to the pulse motor are output. Compare with By comparing the actual drive pulse with the command pulse, it is possible to determine whether or not there is a difference between the two pulses. This XY
Correcting the position coordinates of the table makes it easy to accurately sense the chip.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a die bonder according to the present invention will be described with reference to FIGS. 3 and 4 are denoted by the same reference numerals.

The die bonder of the present invention has the same structure as the conventional die bonder shown in FIG.
As shown in FIG. 1, a wafer 2 divided into a large number of chips 1 is attached to an adhesive sheet 3, and the adhesive sheet 3 is mounted with a wafer ring 4 stretched on a ring-shaped frame, and a pulse motor 5x, XY table 6 driven by 5y
And a camera 7 arranged above the XY table 6 to image each chip 1 of the wafer ring 4 and recognize the image.
And a suction collet 8 for sucking and holding the chip 1 of the wafer ring 4, picking it up, transferring it to a predetermined position such as a lead frame, and mounting it.

The present invention is characterized in that pulse motors 5x, 5y for driving the XY table 6 are provided with encoders 11x, 11y, and the encoders 11x, 1y are provided.
The feedback pulses Px ₂ and Py ₂ output from the counter 1x are counted by the counters 12x and 12y.
Actual drive pulses Px ₃ , Py ₃ output from 2x, 12y and command pulses Px ₁ , applied to pulse motors 5x, 5y,
In that so as to sense with coordinates modify the XY table 6 based on the comparison of the py _1.

Specifically, predetermined command pulses Px ₁ , Py ₁ are based on commands Sx, Sy from a control device (not shown).
Oscillators 13x and 13y for generating the pulse trains and command pulses Px ₁ and Px ₁ output from the pulse oscillators 13x and 13y.
Drivers 14x, 14y for driving and controlling the pulse motors 5x, 5y by Py ₁ and feedback pulses Px ₂ , Py ₂ output from encoders 11x, 11y attached to the pulse motors 5x, 5y are counted. comprises counter 12x for outputting an actual driving pulse Px _3, Py ₃ obtained by 5y is actually rotated, and 12y.

Incidentally, as shown in FIG.
3x, 13y, drivers 14x, 14y, pulse motors 5x, 5y, encoders 11x, 11y, and counter 1
Each of the components 2x and 12y requires two systems for the X and Y axes of the XY tables 5x and 5y.

In the die bonder, when the wafer ring 4 is set on the XY table 6, the pulse oscillators 13x and 13x are set based on commands Sx and Sy from the control device.
13y, the command pulses Px ₁ and Py ₁ are generated, and the pulse motors 5x and 5y are driven by the drivers 14x and 14y based on the command pulses Px ₁ and Py ₁ . By driving the pulse motors 5x and 5y, the XY table 6 is moved at a constant pitch, and each chip 1 of the wafer ring 4 is sensed while the camera 7 recognizes an image.

The sensing of the chip 1 is performed based on rank-specific data of non-defective products obtained at the time of checking the characteristics of the wafer 2 described above.
A desired chip 1 is sequentially arranged at a position corresponding to the suction collet 8 by moving the Y table 6. At this time, the position of the chip 1 is corrected by the image recognition by the camera 7 and the positioning is completed. The chips 1 are picked up by the suction collet 8 for each rank, transferred to a lead frame or the like, and mounted.

At the time of sensing of the chip 1, as described above, the pulses driven by the drivers 14x and 14y based on the command pulses Px ₁ and Py ₁ output from the pulse oscillators 13x and 13y by the commands Sx and Sy from the control device. In the motors 5x and 5y, the pulse motors 5x and 5y
XY by encoders 11x and 11y attached to
The rotation number corresponding to the constant pitch movement of the table 6 is detected, and feedback pulses Px ₂ and Py ₂ corresponding to the rotation number are output. The feedback pulses Px ₂ , Py ₂ output from the encoders 11x, 11y are converted into counters 12x,
It counted by 12y, and outputs the amount of the XY table 6 has actually moved a constant pitch as an actual driving pulse Px _3, Py _3.

In the control device, the counters 12x,
Actual driving pulse Px ₃ output from 12y, Py ₃ and a pulse motor 5x, the command pulse Px _1, P applied to 5y
comparing the y _1, by comparison with the actual drive pulse Px _3, Py ₃ and command pulse Px _1, Py _1, it is possible to determine whether the difference of both pulses. That is, if there is no difference between the two pulses, no displacement of the XY table 6 due to the occurrence of motor out-of-synch has occurred. If there is a difference between the pulses, the position coordinates of the XY table 6 are corrected. By correcting the position coordinates of the XY table 6, the chip 1
It is easy to realize accurate sensing of The correction of the position coordinates at the time of sensing is set so as to be executed every time the XY table 6 is driven or every cycle of mounting.

The sensing of the chip 1 is executed while correcting the position coordinates as described above. After the positioning of the chip 1 is completed, the chip 1 is picked up by the suction collet 8 and then transferred to a lead frame or the like for mounting. . In this manner, a large number of chips 1 on the wafer ring 4 are die-bonded for each rank.

In the above embodiment, as shown in FIG. 1, the actual driving pulses P output from the counters 12x and 12y are used.
Although the case has been described where x ₃ and Py ₃ are compared with the command pulses Px ₁ and Py ₁ , the present invention is not limited to this. For example, as shown in FIG.
Feedback pulses Px ₂ and Py ₂ output from 11y
Are determined by the deviation counters 15x and 15y as command pulses Px ₁ ,
Compared with py _1, the deviation counter 15x, may output a deviation pulse Px _4, Py ₄ from 15y.

[0027]

According to the die bonder of the present invention, XY
An encoder is attached to the table, a feedback pulse output from the encoder is counted by a counter, and XY is determined based on a comparison between an actual drive pulse output from the counter and a command pulse applied to the pulse motor.
Since the sensing is performed while correcting the position coordinates of the table, it is easy to realize accurate sensing of the chip by correcting the position coordinates of the XY table, without using an expensive servomotor, and reducing the current motor speed. It is possible to provide an inexpensive die bonder by preventing displacement of the motor due to loss of synchronism without dropping and changing existing equipment with minimum cost.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a main part for describing an embodiment of a die bonder according to the present invention.

FIG. 2 is a main part circuit block diagram of a modified part showing a modified example of the present invention.

FIG. 3 is a front view showing a schematic configuration for explaining a conventional example of a die bonder.

FIG. 4 is a plan view showing a schematic configuration of a die bonder.

[Explanation of symbols]

1 chip 2 wafer 3 sheets 5x, 5y pulse motor 6 XY table 11x, 11y encoder 12x, 12y counter 15x, 15y deviation counter Px _1, Py ₁ command pulses Px _2, Py ₂ feedback pulses Px _3, Py ₃ the actual driving pulse Px ₄ , Py ₄ deviation pulse

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-218115 (JP, A) JP-A-60-183733 (JP, A) JP-A-60-124944 (JP, A) JP-A-4- 67696 (JP, A) JP-A-4-359499 (JP, A) JP-A-4-312372 (JP, A) JP-A-4-52742 (JP, U) JP-A-63-18839 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 21/52

Claims (3)

(57) [Claims] 1. A semiconductor wafer is mounted on an XY table in a state where the semiconductor wafer is attached to a sheet, and the XY table is moved at a constant pitch in the XY directions by driving a pulse motor based on a command pulse to constitute the wafer. In a die bonder which mounts a chip after sensing and picking up a chip from a sheet, an encoder is attached to a pulse motor for driving the XY table, a feedback pulse output from the encoder is counted by a counter, and output from the counter. A die bonder characterized in that sensing is performed while correcting position coordinates of an XY table based on a comparison between an actual driving pulse and the command pulse given to a pulse motor. 2. The method according to claim 1, wherein the difference between the feedback pulse and the command pulse output from the encoder is counted by a deviation counter, and the XY table is sensed while correcting the position coordinates based on the deviation pulse output from the deviation counter. The die bonder according to claim 1, wherein: 3. A control device for issuing a predetermined command based on electrical characteristic data of a semiconductor wafer measured in advance, and an XY for mounting the semiconductor wafer in a state of being attached to a sheet.
A table, a pulse generator for generating a predetermined command pulse based on the command, and the XY based on the command pulse.
A pulse motor for moving the table at a constant pitch, an encoder attached to the pulse motor and outputting a feedback pulse, and a counter for counting the feedback pulse and outputting an actual drive pulse to the control device,
A die bonder which moves the XY table while correcting position coordinates based on a comparison between the actual drive pulse and the command pulse.