JP2995435B2 - Automatic chip sorting and conveying device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic chip sorting / conveying apparatus, and more particularly to a chip aligning apparatus for judging the quality of a chip conveyed on a semiconductor wafer loading table by an optical detection device. Pressing and picking up chips from the semiconductor wafer loading table, and simultaneously checking the quality of the chips transported to the chip alignment device by the optical detection device again, and moving the chips from the semiconductor wafer loading table at an extremely high speed. The present invention relates to an automatic chip sorting / conveying apparatus having an epoch-making performance capable of being conveyed to a chip.

[0002]

2. Description of the Related Art Referring to FIGS. 4 and 5, a semiconductor wafer 1 is a general term for a thin disk-shaped semiconductor, and is generally cut into a disk from a single crystal base material purified into a columnar shape. One surface 1a is mirror-polished, and various semiconductor elements are formed on the surface by etching or the like.

The dimensions of the semiconductor wafer 1 are, for example, 10 to 400 mm in diameter and 200 μm to 10 m in thickness.
m, and a so-called orientation flat 1b is formed by linearly grinding an outer peripheral portion, that is, a part of an end face, in order to easily adjust the circumferential orientation.

A large number of semiconductor elements manufactured on the semiconductor wafer 1 by an etching method or the like are inspected one by one for electrical characteristics, and if the predetermined characteristics are not obtained, marks 1c are marked as defective elements (probing process). ).

A semiconductor wafer 1 having a mark 1c on a defective element is attached to a tape 2 and cut into chips (semiconductor elements) 1d each having a side of 0.5 mm to 20 mm by a cutting device (not shown). Separated.

[0006] A good chip 1d having no mark is selected from a large number of separated chips 1d, picked up, sorted into trays, or conveyed to a bonding step.

In the conventional chip 1d conveying apparatus, in FIG. 6, a male screw 5 screwed with a nut 4 to which a collet 3 holding the chip 1d is fixed is rotated in the direction of arrow A or B by a pulse motor or a servomotor 6. The collet 3 is conveyed in the direction of arrow C or D.

However, the feed screw type transfer device has little vibration and is excellent in stability, but it is difficult to operate at high speed.
However, the processing of the semiconductor wafer 1 on which approximately 8000 chips 1d are formed takes too much time and is not economical.

As another transporting device, as shown in FIG. 7, a wire 1 in which a collet 9 is fixed to a pair of pulleys 8 is used.
There is known an apparatus in which the pulley 8 is wound around the motor 0 and the motor 11 rotates the pulley 8 in the direction of arrow E or F to convey the collet 9 in the direction of arrow G or H.

Although the wire-type transfer device has a great improvement in the high-speed operation as compared with the feed screw-type transfer device, vibrations at the time of stoppage due to the elasticity of the wire 10 and elongation over time, etc. There is a disadvantage that it is difficult to secure the positional accuracy due to the change in the position.

As another transporting device, as shown in FIG. 8, two collets 14 are fixed to a rotating shaft 13 of a motor 12, and the motor 12 is intermittently rotated in the direction of arrow I at every 180 ° to rotate the rotating shaft. One that transports the chip 1d to 13 symmetrical positions has been employed.

Although the transfer device is greatly improved in high-speed operation and positional stability, since two collets 14 are arranged at symmetrical positions of the rotating shaft 13, the true position of the chip 1d to be transferred is improved. While the mark 1c attached to the chip 1d is detected by the optical detection device disposed above and the quality of the chip 1d is determined, the collet 14 is rotated so as not to interfere with the quality determination. It was necessary to wait at an intermediate position, and there was still room for improvement in speed.

Also, in any of the above-described conveying devices, the vertical movement of the collet 4 is controlled by the cylindrical cam with which the collet 4 is engaged, so that the vertical position of the collet 4 at the time of picking up and pressing the chip 1d. However, there are drawbacks such as difficulty in fine adjustment of the chip 1d, unreliable delivery of the chip 1d, and damage of the chip 1d by strongly pressing the collet 4 against the chip 1d.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks of the prior art, and has as its object to provide at least 120 points on the same circumference around the rotation axis. By disposing three sets of collets at an interval of 60 ° and intermittently rotating the collet by 60 ° around the rotation axis to convey the chips, the quality of the conveyed chips is determined by an optical detection device and the chips are aligned at the same time. Aligning the chips in the device and pressing it, and picking up the chips from the semiconductor wafer mounting table, and at the same time checking the quality of the chips transported to the chip alignment device by means of an optical detection device, and thereby, Eliminate downtime of the automatic chip sorting and transporting equipment to improve operating efficiency and to transport chips much faster than before. Is Rukoto.

Another object of the present invention is to make it possible to determine whether a chip is good or bad twice by using the above-mentioned structure before and after the transfer so that the transfer of a defective element can be reliably prevented.

Still another object is to move a collet up and down by using a servo motor capable of arbitrarily setting a vertical stop position of the collet, so that a single servo motor can be used for semiconductors having different heights. To be able to transport chips from the wafer loading table to the chip alignment device, to facilitate adjustment of the collet stop position, and to ensure chip delivery with the optimal spacing between the chip and the collet during delivery. And transporting the chip without damaging it.

[0017]

SUMMARY OF THE INVENTION In summary, the present invention (claim 1) provides a semiconductor wafer loading device in which a plurality of chips are diced and the semiconductor wafer is moved in an X direction and a Y direction orthogonal to the X direction. A chip, a chip alignment device for aligning non-defective chips conveyed from the semiconductor wafer mounting table in a predetermined position while moving the chips in the X and Y directions, and detecting a mark attached to the chip to detect the mark on the chip. An optical detection device disposed at least above the conveyed chip for judging pass / fail and arranged at equal intervals on the same circumference centered on the rotation axis and rotatable around the rotation axis; And at least three sets of chips that are moved in the axial direction of the rotation axis by a driving device, pass the good chips from the semiconductor wafer mounting table, and transport the chips to the chip alignment device. It is characterized in that a let.

Further, the present invention (claim 2) provides a semiconductor wafer mounting table for mounting a semiconductor wafer diced on a plurality of chips and moving in a X direction and a Y direction orthogonal to the X direction. A chip aligning device for aligning non-defective chips conveyed from a wafer mounting table at predetermined positions while moving in the X and Y directions, and detecting marks on the chips to determine the quality of the chips; And at least one optical detection device disposed above the chip to be conveyed on the same circumference around the rotation axis.
The chips are arranged at intervals of 20 °, intermittently rotate by 60 ° around the rotation axis, and are moved in the axial direction of the rotation axis by a driving device to deliver the good chips from the semiconductor wafer loading table to the chip alignment device. And three sets of collets for transporting the chips.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. With reference to FIGS. 1 to 5, an automatic chip sorting and conveying device 20 according to the present invention includes a semiconductor wafer loading table 21,
A chip alignment device 22, an optical detection device 23, and a collet 24 are provided.

Referring to FIG. 1, the semiconductor wafer loading table 21 loads the semiconductor wafer 1 diced into a plurality of chips 1d, moves in the direction of arrow J or K and the direction of arrow L or M, and then transports the semiconductor wafer. This is a known XY moving device for sequentially transferring chips 1d to be picked up to a predetermined pickup position by the collet 24.

The tape 2 is mounted on the semiconductor wafer mounting table 21.
Is positioned and loaded by the orientation flat 1b.

Below the predetermined pick-up position by the collet 24, there is provided a chip peeling device (not shown) in which a needle is mounted so as to face upward. 1d is peeled from the tape 2 and delivered to the collet 24.

The chip aligning device 22 is for aligning non-defective chips 1d conveyed from the semiconductor wafer mounting table 21 by the collet 24, and is a known XY device.
It is a moving device, and a tray 25 for storing chips 1d is loaded on the table 22a.

Each time the chip 1d is conveyed by the collet 24, the tray 25 is moved in the direction of arrow N or O and in the direction of arrow P or Q so that the chip 1d is aligned and stored (pressed) in the tray 25. Has become.

The optical detecting device 23 is for judging the quality of the chip 1d, and is constituted as, for example, a microscope device or an image processing device in conjunction with a CCD camera or the like. The chip 1d is focused and disposed above a predetermined pickup position of the semiconductor wafer mounting table 21, and detects the shape of the chip 1d and the defective mark 1c attached in the electrical inspection process to detect the chip 1d. Pass / fail is determined.

The optical detecting device 23 is also provided above the pressing position of the chip aligning device 22 to check again the chips 1d aligned and stored (pressed) in the tray 25, and to check the defective chips 1d. It is designed to prevent accidental transport.

The collet 24 is for transporting the chip 1d from the semiconductor wafer loading table 21 to the tray 25 of the chip aligning device 22, and the base 2 is also referred to with reference to FIG.
A rotating shaft 29 is pivotally attached to a support base 28 fixed to 6.

A cylindrical cam body 30 is provided below the support base 28.
The guide pin 31 fixed to the cylindrical cam body 30 is slidably fitted to the guide block 28a of the support base 28 to move the cylindrical cam body 30 up and down in the arrow R or S direction. Holding.

An AC servomotor 32 that can be stopped at an arbitrary position, which is an example of a driving device, is fixed to the support base 28 and is screwed to a male screw 34 fixed to a rotation shaft 33 of the AC servomotor 32. The feed block 35 is fixed to the cylindrical cam body 30, and is configured to move the cylindrical cam body 30 in the arrow R or S direction by rotating the AC servomotor 32.

The stop position of the cylindrical cam body 30 due to the rotation of the AC servomotor 32 is such that the collet 24 contacts the chip 1d loaded on the semiconductor wafer loading table 21 and the chip 1d is peeled off from the tape 2. Three positions are set: a retreat position for picking up, and a press position for pressing the chip 1d conveyed to the chip aligning device 22 to the chip aligning device 22, and the respective stopping positions can be adjusted in units of 10 μm. .

The upper end of the rotating shaft 29 is connected to a rotating shaft (not shown) of a driving device 36 which can be stopped at an arbitrary position such as an AC servomotor or a step motor, and the collet 24 stops every 60 °. It is set to rotate intermittently. Also, three sets of stays 38 are fixed to the lower end 29a at 120 ° intervals.

A movable block 40 in which the collet 24 is fixed by screws 39 is fitted into a guide groove 38a formed on the outer periphery of the stay 38, and guides the movable block 40 to slide in the directions of arrows T and U. It is configured to be movable.

At the upper end 40a of the movable block 40, a vertical lift amount formed on the outer periphery of the cylindrical cam body 30 is approximately two.
A guide roller 41 slidably fitted in the 0 mm cam groove 30a is mounted by a screw 42.

The three sets of collets 24 include a movable block 40.
, And are arranged at 120 ° intervals on the same circumference around the axis of the rotating shaft 29.

When the rotary shaft 29 is driven by the driving device 36, the three sets of stays 38 are also rotated, and the movable block 40 fitted into the guide groove 38a is rotated around the cylindrical cam body 30 and is also inserted into the cam groove 30a. Guided arrows T and U
A vertical movement is performed in the direction.

That is, the collet 24 located on the semiconductor wafer mounting table 21 is guided by the cam groove 30a as it rotates toward the chip alignment device 22 (in the direction of arrow V), and is lifted by the lift amount (20 mm). It gradually rises (in the direction of arrow T), and the lift amount of the cam groove 30a is set to be substantially the same as the difference in height between the conductive wafer mounting table 21 and the chip alignment device 22. .

The collet 24 is connected to a vacuum device (not shown) by a tube 43. The collet 24 controls the vacuum device so that the chip 1d is attracted by the collet 24 and picked up from the semiconductor wafer mounting table 21, and the chip alignment device 22 To press.

The present invention is configured as described above,
Hereinafter, the operation will be described. Referring to FIG. 3 as well, the semiconductor wafer mounting table 21 is moved in the direction of the arrow J or K and in the direction of the arrow L or M to position the chip 1d to be transported next below the optical detection device 23.

Next, it is checked by the optical detection device 23 whether the shape of the chip 1d to be transported next is a normal shape and whether or not the defective mark 1c is attached.
Confirm that the chip 1d is a good product.

At this time, since the positional relationship between the three sets of collets 24 is as shown in FIG. 3, the three sets of collets 24 are rotated by the driving device 36 through the rotating shaft 29 in the direction of arrow V by 60 °. , One of the collets 24 into the cam groove 30
While being lowered along a, it is positioned slightly above the chip 1d to be transported next after it is checked that it is a good product.

The male screw 34 is driven to rotate by the AC servomotor 32, and the tip of the collet 24, which is located slightly above the chip 1d to be transported next to the cylindrical cam 30 together with the feed block 35 screwed to the screw, is attached to the chip 1d. The tip 1 d is lowered to the contact position in the direction of arrow U, and the chip 1 d is attracted to the collet 24 by a vacuum device (not shown).

The AC servomotor 32 is again rotated in the opposite direction to raise the collet 24 in the direction of arrow T, and in conjunction with this, the needle of a chip peeling device (not shown) is pushed up through the tape 2 to raise the chip. 1d to tape 2
, And delivered to the collet 24.

In the pickup step, the collet 2
Unlike the conventional cam control, the ascending movement of the needle 4 and the needle of the chip peeling device is completely synchronized and controlled by electronic control. Therefore, the collet 24 is strongly pressed by the chip 1d and damages the chip 1d. Never.

From the semiconductor wafer mounting table 21 to the chip 1
While picking up d, none of the three collets 24 of the three sets of collets 24 are located above the press position of the chip aligning device 22, and the chips 1d already conveyed and aligned on the tray 25 are good. Whether or not it is checked again by the optical detection device 23.

When the driving device 36 is driven again to rotate the three sets of collets 24 further in the direction of arrow V by 60 °, the collets 24 are guided by the cam grooves 30a and rise approximately 20 mm (in the direction of arrow T). The positional relationship shown in FIG. That is, the collet 24 is not located below the optical detection device 23 of the semiconductor wafer mounting table 21, but is located at the press position of the chip alignment device 22.

Here, the AC servomotor 32 is rotated to lower the collet 24 in the direction of the arrow U, and the operation of the vacuum device of the collet 24 at the press position is stopped.
d is detached from the collet 24, aligned in an empty tray 25, and stored (pressed).

At the same time, the semiconductor wafer mounting table 21 is moved in the direction of the arrow J or K and in the direction of the arrow L or M so that the next chip 1d to be conveyed is positioned below the optical detecting device 23, The detection device 23 checks whether or not the chip 1d to be transported next is good. If the shape of the chip 1d is not a predetermined shape or a defect mark 1c is attached, the semiconductor wafer mounting table 21 is again moved to the arrow J or K direction and the arrow L
Alternatively, the same operation is repeated until the non-defective chip 1d is detected by moving in the M direction, and the non-defective chip 1d is positioned at the pickup position.

After the chips 1d are stored (pressed) in the tray 25, the collet 24 is raised by rotating the AC servomotor 32 again, and the chip aligning device 22 is moved in the directions of arrows N or O and arrows P or Q. Then, the empty tray 25 is positioned below the pressing position to prepare for the next conveyance of the chip 1d.

The above-described operation of intermittently rotating the collet 24 every 60 ° is repeated, and the chips 1d are transferred one by one from the semiconductor wafer mounting table 21 to the tray 25 of the chip alignment device 22 at a high speed in the direction of arrow W and stored. I do.

Next, the relationship between the number of the collets 24 and the time required for transporting the chips 1d will be described with reference to Table 1.

[0051]

[Table 1]

In Table 1, the image processing time required for the quality judgment of the chip 1d by the optical detection device 23 is 0.2.
In seconds, the pick-up time required for picking up the chip 1d from the semiconductor wafer mounting table 21 is 0.3 seconds, and the press time required for storage in the chip aligning device 22 is 0.2 seconds, which is constant regardless of the number of collets 24.

One collet 24 and one chip 1
In the case of Example 1 of the conventional method that requires 180 ° rotation for transport of d, by rotating the collet 24 intermittently by 90 °, the quality of the chip 1d is determined when the collet 24 is at the intermediate position rotated by 90 °. Since the determination is made, no independent image processing time is required. Therefore, one chip 1d
The time required for transporting the collet 24 is the time required for rotating the collet 24 by 180 °, which is 0.9 seconds, is added to each of the above times, and the total time is 1.4 seconds.

In the case of Example 2 of the conventional method in which the number of the collets 24 is two and the conveyance of one chip 1d requires 90 ° rotation, the time required for rotating the collet 24 by 90 ° is also 0. 45 seconds are added to each of the above times,
The total time is 0.95 seconds.

In the third embodiment of the present invention in which the number of the collets 24 is three, the required rotation time for rotating the collet 24 by 60 ° 0.3 seconds is added, and the total time is 0.8 seconds.

Further, in Examples 4 and 5 in which four and five collets 24 are provided, the rotation angles are 45 ° and 36 °, respectively, and the total time is 0.725 seconds and 0.68 seconds. Become.

As shown in Table 1, as the number of collets 24 increases, the transport time per chip becomes shorter.
Since the mechanism becomes more complicated as the number of collets 24 increases, the number of collets 24 is about three, which is the most efficient configuration example as a whole.

In the above embodiment, the chip aligning device is described as storing chips in a tray. However, the chip aligning device is not limited to the device storing chips in a tray. Any device in the next step, such as a loading device, may be used.

[0059]

As described above, according to the present invention, three sets of collets are arranged at intervals of at least 120 ° on the same circumference around the rotation axis, and the collets are intermittently rotated by 60 ° around the rotation axis. Since the chips are transported, the quality of the transported chips is determined by an optical detection device, and at the same time, the chips are aligned and pressed by a chip alignment device. There is an effect that the quality of the chips conveyed to the alignment device can be confirmed again by the optical detection device, and as a result, the operation efficiency is improved by eliminating the downtime of the automatic chip sorting and conveying device, and the chip is much faster than before. Can be transported.

With the above configuration, the quality of the chip is determined twice before and after the transfer, so that the transfer of the defective element can be reliably prevented.

Further, since the collet is moved in the vertical direction by using a servomotor which can arbitrarily set the stop position of the collet in the vertical direction, the semiconductor wafers having different heights can be moved by one servomotor. There is an effect that the chips can be transported from the loading table to the chip aligning device, and as a result, the collet stop position can be easily adjusted, and the chips can be reliably delivered with the optimal spacing between the chips and the collet at the time of delivery. In addition, there is an effect that the chips can be transported without damaging them.

[Brief description of the drawings]

FIGS. 1 to 5 relate to an embodiment of the present invention, and FIG. 1 is an overall perspective view of an automatic chip sorting / conveying apparatus.

FIG. 2 is a front view of a main part of the automatic chip sorting and conveying device.

FIG. 3 is a plan view showing a chip conveyance state by a collet.

FIG. 4 is a front view showing a diced semiconductor wafer.

FIG. 5 is a plan view of a semiconductor wafer with a mark of a defective element.

6 to 8 are related to a conventional example, and FIG. 6 is a front view of a feed screw type transfer device.

FIG. 7 is a front view of a wire-type transfer device.

FIG. 8 is a front view of a rotary transfer device having two collets.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor wafer 1c mark 1d chip 20 automatic chip sorting and conveying device 21 semiconductor wafer loading table 22 chip alignment device 23 optical detection device 24 collet 29 rotation axis 36 servo motor as an example of driving device

[Table 1]

Claims (3)

(57) [Claims] 1. A semiconductor wafer diced on a plurality of chips is stacked and mounted in an X direction and a Y direction orthogonal to the X direction.
The semiconductor wafer loading table moving in the direction and the non-defective chips transported from the semiconductor wafer loading table are moved in the X direction and the Y direction.
A chip aligning device for aligning a chip at a predetermined position while moving in a direction, and an optical detection device disposed at least above the chip to be conveyed for detecting a mark on the chip and determining whether the chip is good or bad The device and the semiconductor wafer loading table are arranged at equal intervals on the same circumference around the rotation axis, are configured to be rotatable around the rotation axis, and are moved in the axial direction of the rotation axis by a driving device. An automatic chip sorting / conveying device, comprising: at least three sets of collets for receiving the non-defective chips and conveying the chips to the chip aligning device. 2. A semiconductor wafer diced on a plurality of chips is mounted on a semiconductor chip, and the semiconductor wafer is diced into a plurality of chips.
The semiconductor wafer loading table moving in the direction and the non-defective chips transported from the semiconductor wafer loading table are moved in the X direction and the Y direction.
A chip alignment device for aligning the chip at a predetermined position while moving in a direction, and a chip alignment device disposed at least above the chip to be conveyed so as to detect a mark attached to the chip and determine whether the chip is good or bad. An optical detection device, the semiconductor being arranged at intervals of 120 ° on the same circumference around the rotation axis, intermittently rotating by 60 ° around the rotation axis, and moving in the axial direction of the rotation shaft by a driving device; An automatic chip sorting / conveying apparatus, comprising: three sets of collets that deliver the non-defective chips from the wafer mounting table and convey the chips to the chip aligning apparatus. 3. The automatic chip sorting and conveying device according to claim 1, wherein the driving device is a servomotor that can set a stop position to an arbitrary position.