JPH09293695A - Dicing device equipped with visual inspection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent a cutting failure from occurring continuously in a dicing device by a method wherein the surface of a semiconductor wafer subjected to a cutting process and relatively transferred by an X-Y-θ drive stage is imaged by an imaging means, image signals are outputted from the imaging means, and the state of the split semiconductor wafer is checked from the image signals. SOLUTION: A semiconductor wafer 2 is transferred to a loading/unloading wafer standby station 14 located properly distant from a loading/unloading station 3 in the direction of a Y axis from the station 13, and then the wafer 2 is transferred to an alignment station 6 on an X-Y-θ drive stage 10'. An image sensing camera 18 is arranged above the alignment station 6, the surface of the semiconductor wafer 2 is imaged by the image sensing camera 18, image signals outputted from the image sensing camera 18 are inputted into a picture image processing section, the alignment state of the semiconductor wafer 2 is judged by the picture image processing section, and it is checked in a visual inspection process whether a semiconductor chip is defective or not. By this setup, a semiconductor wafer 2 can be surely protected against cutting failures which occur in succession.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dicing apparatus for cutting a semiconductor wafer vertically and horizontally to divide it into individual semiconductor chips in a semiconductor manufacturing process.
The present invention relates to a dicing device having an appearance inspection function having an inspection function of a semiconductor chip after cutting.

[0002]

2. Description of the Related Art Semiconductor chips are obtained by dividing a semiconductor wafer by cutting. By the way, chipping or cracking may occur in the semiconductor chip due to cutting. If such chipping or cracking occurs, not only the assembling failure of the semiconductor chip may occur in the mounting process of the subsequent process, but also the IC circuit may be damaged. If the IC circuit is damaged, the operation will be abnormal.

Therefore, conventionally, an inspection step is provided after the cutting step to visually inspect the semiconductor wafer after cutting,
I was removing a semiconductor chip that had chipped or cracked.

However, the visual inspection requires the skill and has a problem that the inspection time becomes long. Therefore, recently, a dicing device having an appearance inspection function for automatically inspecting a semiconductor wafer after cutting has been developed.

As a conventional example of a dicing apparatus having such a visual inspection function, there are one disclosed in Japanese Patent Laid-Open No. 5-152432 and one disclosed in Japanese Patent Laid-Open No. 171754.

FIG. 5 shows a dicing device disclosed in Japanese Patent Laid-Open No. 5-152432 (hereinafter referred to as a first conventional example). This dicing device includes a conveyor 1 for conveying a semiconductor wafer 2 in the X-axis direction (horizontal direction), and an XY drive stage movable in the Y-axis direction (vertical direction) orthogonal to the X-axis direction. 10, a dicing blade 11 for cutting arranged at a cutting position of the semiconductor wafer 2, and X-
Imaging camera 9 arranged in the moving range of the Y drive stage 10.
And the air curtain 12 and the like arranged in the movement range of the XY drive stage 10 in the X-axis direction. The operation will be described below.

First, the semiconductor wafer 2 is placed at the loading / unloading position 3 corresponding to the upstream side in the moving direction of the transfer conveyor 1. Then, the transfer conveyor 1 transfers the semiconductor wafer 2 to the pre-alignment position 4. At this pre-alignment position 4, approximate alignment adjustment is performed with reference to the orientation flat. After pre-alignment, the semiconductor wafer 2 is X
-Transfer to the transfer position 5 of the Y drive stage 10. The transfer position 5 is located on the upstream side of the movement range of the XY drive stage 10 in the X-axis direction.

The XY drive stage 10 has the transfer position 5
To the alignment position 6 on the downstream side in the X-axis direction. An imaging camera 9 is arranged above the alignment position 6, and the surface of the semiconductor wafer 2 is imaged by the imaging camera 9. The image pickup signal of the image pickup camera 9 is
It is output to a control device (not shown). The control device performs image processing on the image pickup signal and determines the alignment state of the semiconductor wafer 2. The result of this determination is fed back to the XY drive stage 10 to perform precise alignment adjustment.

When the alignment adjustment is completed, the XY drive stage 10 moves to the cutting position 7 on the further downstream side.
Then, the dicing blade 11 cuts the semiconductor wafer 2. The semiconductor wafer 13 after cutting is transferred to the upstream side by the XY drive stage 10 and arranged in the middle of the moving range of the XY drive stage 10.
Thus, the water droplets attached in the cutting process are removed. After that, the XY drive stage 10 moves to the appearance inspection position 8 in the Y-axis direction via the alignment position 6. At this time, the imaging camera 9 also moves from the alignment position 6 to the visual inspection position 8.

At the appearance inspection position 8, the image pickup camera 9 picks up an image of the surface of the semiconductor wafer 13 after cutting, and after the semiconductor wafer 2 is aligned, recognition and appearance inspection processing of the surface is performed. That is, the appearance inspection automatically inspects the semiconductor chip for chipping or cracking.

FIG. 6 shows a dicing device disclosed in Japanese Patent Laid-Open No. 171754/1995. In this dicing device, image pickup cameras 16 and 17 are arranged at an alignment position 6 and an appearance inspection position 8, respectively. The same parts as those of the first conventional example are designated by the same reference numerals, and the operation of this dicing apparatus will be described below.

When the semiconductor wafer 2 is placed at the loading / unloading position 3, a transfer device (not shown) passes through the loading / unloading wafer standby position 14 which is separated from the loading / unloading position 3 by an appropriate distance in the Y-axis direction. 2 is transferred to the alignment position 6 corresponding to the downstream side of the loading / unloading position 3 in the X-axis direction, that is, to the upstream side of the XY drive stage 10 in the X-axis direction. Then, the image pickup camera 16 arranged at the alignment position 6 picks up an image of the surface of the semiconductor wafer 2, and the same precise alignment adjustment as described above is performed based on the image pickup signal.

When the alignment is completed, the XY drive stage 10 moves to the cutting position 7 and the dicing blade 11 cuts the semiconductor wafer 2. After that, the XY drive stage 10 moves to the upstream side in the X-axis direction, and water droplets attached to the semiconductor wafer 13 after cutting are removed by the air curtain 12 in the middle thereof. Then, X
The -Y drive stage 10 moves to the wafer cleaning position 15 in the Y-axis direction via the alignment position 6, where the semiconductor wafer 13 is cleaned. Subsequently, the semiconductor wafer 13 is transferred from the wafer cleaning position 15 to a visual inspection position 8 which is further separated from the wafer cleaning position 15 by an appropriate distance in the Y-axis direction by a transfer unit (not shown). That is, the presence or absence of chips or cracks is automatically inspected.

In both the first conventional example and the second conventional example, a dedicated visual inspection position 8 is provided in order to perform visual inspection of the semiconductor wafer 13 after cutting. Therefore, there is an advantage that wasteful time in the working process can be eliminated. That is, for example, when the appearance inspection position 8 is provided on the straight line connecting the alignment position 6 and the cutting position 7, the next dicing process of the semiconductor wafer 2 is performed until the cutting / appearance inspection process of one semiconductor wafer 2 is completed. It cannot be done, and a waiting time occurs. However, if the appearance inspection position 8 is provided at a position deviating from this line, the next alignment process and cutting process of the semiconductor wafer 2 can be performed while the appearance inspection of the previous semiconductor wafer 2 is being performed.

[0015]

However, securing a dedicated visual inspection position 8 on the side of the line and adding equipment for that purpose necessitates a major design change of the existing equipment, which reduces the equipment cost. Since it causes an increase in the size and the installation space for the dicing device becomes large, it is difficult to apply it to a factory with a limited space.

In consideration of quality assurance, abnormal cutting (abnormal cutting), which is an inspection item, occurs due to wear or breakage of cutting teeth of the dicing blade 11. For this reason, if the dicing blade 11 in which the cutting teeth are worn or broken is subsequently used to cut the semiconductor wafer 2 in the next order, abnormal cutting occurs continuously.

Here, in the above-mentioned conventional example, since the cutting process of the next semiconductor wafer 2 is performed while the appearance inspection of the previous semiconductor wafer 2 is performed, the cut abnormality is fed back. However, there is a problem in that cutting abnormalities are likely to occur continuously.

Further, since the wafer is transferred to a dedicated visual inspection position 8 different from the alignment position, the semiconductor wafer 2 after cutting must be realigned prior to the visual inspection.

The present invention has been made in view of the above circumstances, and it is possible to effectively utilize existing equipment to suppress an increase in equipment cost and to easily apply it to a factory where space is not available. Moreover, it is an object of the present invention to provide a dicing device having an appearance inspection function that can feed back an abnormality when cutting the next semiconductor wafer and can reliably prevent continuous occurrence of cutting abnormality. To do.

Another object of the present invention is to provide a dicing apparatus equipped with a visual inspection function, which does not require realignment of a semiconductor wafer to be inspected at the time of visual inspection and can perform an inspection process quickly. .

[0021]

A dicing apparatus having a visual inspection function of the present invention is movable in the X-axis direction and the Y-axis direction and rotatable in a horizontal plane, and has an alignment position and a cutting position. An XY-θ drive stage that moves over the X-Y-θ stage and the X-Y-θ drive stage that is disposed at the alignment position.
Image pickup means for picking up an image of the surface of the semiconductor wafer placed on the Y-θ drive stage, alignment means for recognizing the posture of the semiconductor wafer based on an image pickup signal from the image pickup means, and performing alignment processing, and the cutting means. The semiconductor wafer, which is arranged at a position and relatively moved in the X-axis direction by the XY-θ drive stage, is moved along the streets in the X-axis direction and the Y-axis direction based on the information from the alignment means. Based on the cutting means for cutting and the image pick-up signal from the image pick-up means for picking up an image of the surface of the semiconductor wafer after cutting which has been relatively transferred in the X-axis direction to the alignment position by the XY-θ drive stage. , And a visual inspection means for inspecting the state of the individually divided semiconductor chips, whereby the above object is achieved.

Preferably, the visual inspection means sets means for setting the amount of movement in the X-axis direction and the Y-axis direction from the cutting line located at the wafer center of the semiconductor wafer after cutting to an arbitrary cutting line, and the movement. XY depending on the quantity
-Θ drive stage or means for moving the image pickup means in the X-axis direction and the Y-axis direction.

Preferably, the visual inspection means is
A means is provided for detecting the kerf width of the semiconductor wafer after the cutting and determining the quality of the semiconductor chip based on the kerf width.

Preferably, the visual inspection means is
It has means for reporting abnormal cutting.

The operation will be described below.

According to the above arrangement, since the alignment position shares the appearance inspection position, it is not necessary to provide a dedicated appearance inspection position. Therefore, the installation space of the dicing device does not become large. In addition, existing equipment can be effectively used. Further, since it is not necessary to transfer the semiconductor wafer after cutting to a dedicated visual inspection position, the realignment process becomes unnecessary. Therefore, the inspection time can be shortened. Further, since the next semiconductor wafer is not cut during the appearance inspection, it is possible to feed back the cutting abnormality obtained by the appearance inspection to the cutting means. Does not cause continuous cracking.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a dicing apparatus having a visual inspection function of the present invention. The configuration will be described below together with the operation. It should be noted that parts common to the first conventional example and the second conventional example are denoted by the same reference numerals.

A loading / unloading position 3 located on the upstream side in the X-axis direction
A plurality of semiconductor wafers 2 are set in the magazine unit. Then, an unillustrated loading / unloading means pulls out an arbitrary semiconductor wafer 2 from the plurality of semiconductor wafers 2 and transfers it to the loading / unloading wafer standby position 14 which is separated from the loading / unloading position 3 by an appropriate distance in the Y axis direction. To do. The carrying-in / carrying-out means again stores the semiconductor wafer that has undergone the dicing process in the carrying-in / carrying-out position 3.

The semiconductor wafer 2 transferred to the wafer loading / unloading wafer standby position 14 is then moved to X by a transfer means (not shown).
It is transferred to the alignment position 6 on the -Y- [theta] drive stage 10 '. This alignment position 6 is the loading / unloading position 3
Are arranged adjacent to each other in the X-axis direction, but the arrangement is not particularly limited. Here, the XY-θ drive stage 10 ′ is movable in the X-axis direction and the Y-axis direction, and is rotatable in the horizontal plane. Above the alignment position 6, an imaging camera 18 such as a CCD camera is provided.
Is arranged, and XY is provided directly below the imaging camera 18.
The semiconductor wafer 2 on the −θ drive stage 10 ′ is stopped.

The image pickup camera 18 picks up an image of the surface of the semiconductor wafer 2 and outputs an image pickup signal to the image processing section 28 shown in FIG. The image processing unit 28 performs image processing on the image pickup signal, determines the alignment state of the semiconductor wafer 2, and outputs the determination result as CP.
U26 (more specifically, a control device equipped with the CPU 26). Then, the CPU 26 issues a predetermined drive command to the drive control unit 27, and the drive control unit 27 which receives the drive command drives the XY-θ drive stage 10 ′, whereby precise alignment adjustment is performed. Further, the image processing unit 28 determines the quality of the semiconductor chip in the appearance inspection step described later.

When the alignment process is completed, XY-
The θ driving stage 10 ′ further moves relative to the downstream side in the X-axis direction while the Y-axis coordinate is fixed, and transfers the semiconductor wafer 2 to the cutting position 7. At this cutting position 7, a dicing blade 11 is arranged. Dicing blade 11
On the basis of the street information inputted from the CPU 26, first, the semiconductor wafer 2 is cut along the street in the X-axis direction while sequentially moving the semiconductor wafer 2 in the Y-axis direction, and then the semiconductor wafer 2 is rotated by 90 °. Then, the semiconductor wafer 2 is diced by cutting along the street in another direction.

When the dicing is completed, the fact is indicated by the CPU.
26. In response to this, the CPU 26 issues a drive command to the drive control unit 27, and the XY-θ drive stage 1
0 ′ is moved toward the alignment position 6. An air curtain 12 is arranged between the alignment position 6 and the cutting position 7, and the wind blown from the air curtain 12 removes water droplets attached to the semiconductor wafer 13 after cutting. Semiconductor wafer 1 from which water droplets have been removed
3 is again stopped at the alignment position 6, where a visual inspection is performed.

The visual inspection is carried out by the image processing section 28 based on the image pickup signal from the image pickup camera 18. In the present embodiment, the chip corner 2 shown in FIG.
2,23 are selected. More specifically, the chip corners 22 that are located near the wafer center 19 of the semiconductor wafer 2 and are individually divided, and the X-axis 20X and the Y-axis 20Y that pass through the wafer center 19 have ± X ₁ in the X-axis direction, respectively.
Four chip corners 23, 23, 23, 23 existing at positions displaced ± Y _{1 in the} Y-axis direction are selected as inspection points. Inspecting the five corners of the chip corners 22, 23 ... Based on the orientation flat 24,
For example, it is performed in the order of the numbers shown in the figure, that is, in the order of the numbers shown in the symbol "□".

Here, the above X ₁ and Y ₁ are the preset X
-Y- [theta] corresponds to the amount of movement of the drive stage 10 '(or the imaging camera 18), and the drive controller 27 that receives a drive command from the CPU 26 changes the X-Y- [theta] each time the chip corner of the inspection target changes. Drive stage 10 'in X-axis direction or Y
The axes are moved by X ₁ and Y ₁ , respectively.

Further, in the present embodiment, the kerf 25 (cut) after cutting is selected as the inspection item of the chip corner. More specifically, the image processing unit 28 that processes the image pickup signal from the image pickup camera 18 measures the width of the kerf 25, and determines the quality of the semiconductor chip, that is, the presence or absence of a chip or a crack, based on the measurement result. This determination result is given to the CPU 26.

Explaining a little now, as shown in FIG. 4 (b), if there is a chip or a crack in the circuit area 2a of the semiconductor chip, these are not generated (see FIG. 4 (a)). Since the width W of the kerf 25 is larger than that of), the quality of the semiconductor chip can be determined by measuring the width W of the kerf 25.

When a cut residue or the like exists in the street due to defective cutting, the kerf width W becomes smaller than a predetermined dimension. Therefore, even if the kerf width W is smaller than the predetermined dimension, it is determined to be defective. If this happens, a semiconductor chip that is not chipped or cracked is also treated as a defective product. Therefore, in order to avoid this, the street portion is masked with respect to the image data obtained by performing image processing on the image pickup signal from the image pickup camera 18. You should keep it.

Further, the kerf width W can be inspected only in one direction line, for example, in the X-axis direction at a time, but in order to inspect the chip corner, two directions, that is, the X-axis direction and the Y-axis direction. Both must be done axially.
However, in the present embodiment, since the semiconductor wafer 13 after cutting is placed on the XY-θ drive stage 10 ′, the XY-θ is finished at the time when the inspection in one direction is completed.
By rotating the drive stage 10 ′ by 90 °, inspection in the X-axis direction and the Y-axis direction, that is, kerf measurement of the chip corner can be performed.

When the image processing unit 28 determines that the semiconductor wafer 13 to be inspected is defective, the CPU 26 having received the determination result notifies the operator of the abnormality. This notification is performed by, for example, an operator call by a monitor and a patrol light (both not shown) attached to the CPU 26.

The operator is the semiconductor wafer 13 to be inspected.
When it is confirmed that the semiconductor wafer 13 is defective, the drive control unit 27 is operated (or a drive command from the CPU 26) to drive the above-mentioned loading / unloading means (not shown) to move the semiconductor wafer 13 to be inspected to the loading / unloading position 3. Discharge. The drive controller 2
Reference numeral 7 controls not only the drive of the XY-θ drive stage 10 ′ but also the entire drive system of the dicing device.

When the operator confirms that the semiconductor wafer 13 is defective, the operator confirms the operating state of the equipment and performs maintenance on the abnormal portion. For example, the cutting teeth of the dicing blade 11 are replaced or the cutting conditions are adjusted (the dicing blade 11 is replaced and the flow rate of cutting water scattered during cutting is adjusted). At this time, the next dicing process of the semiconductor wafer 2 is not performed. Therefore, chip defects due to chipping or cracking due to abnormal cutting are not continuously caused.

On the other hand, when the image processing section 28 determines that the inspection result is good, the CPU 26 issues a drive command to the drive control section 27, and XY-θ by the conveying means (not shown).
The semiconductor wafer 13 on the drive stage 10 ′ is transferred to the wafer cleaning position 15. The wafer cleaning position 15 is provided at a position separated from the alignment position 6 by an appropriate distance in the Y-axis direction.

The semiconductor wafer 13 after being cut at the wafer cleaning position 15 is stored in the loading / unloading position 3 via the loading / unloading wafer standby position 14.

In this embodiment, the semiconductor wafer 13
Although the upper 5 chip corners are inspected, the required time is about 30 seconds, and in general, the appearance inspection of one semiconductor wafer 13 is performed for each of the plurality of semiconductor wafers 2. The overall processing time does not become particularly long. On the other hand, the time required for alignment is usually about 30 seconds to 1 minute, but in the present invention, the semiconductor wafer 13 after cutting is transferred to a dedicated visual inspection position as in the first conventional example and the second conventional example. Since it is not necessary to perform the re-alignment process, the time required for the alignment process can be shortened accordingly. Therefore, as a whole, the first conventional example and the second conventional example
The productivity can be improved as compared with the conventional example.

For the kerf inspection, it is possible to use the inspection method disclosed in, for example, Japanese Unexamined Patent Publication No. 5-326700 instead of the above.

[0047]

As described above, according to the present invention, the alignment position shares the appearance inspection position, so that it is not necessary to provide a dedicated appearance inspection position. Therefore, the installation space of the dicing device does not become large. In addition, since existing equipment can be effectively used without major design changes,
There is an advantage that the equipment cost can be reduced.

Further, since it is not necessary to transfer the semiconductor wafer after cutting to a dedicated visual inspection position, realignment processing becomes unnecessary. Therefore, the inspection time can be significantly shortened, which has the advantage of contributing to the improvement of productivity.

Further, since the next semiconductor wafer is not cut during the visual inspection, the abnormal cutting obtained by the visual inspection can be fed back to the cutting means. Does not cause continuous chipping or cracking. Therefore, there is an advantage that the yield of semiconductor chips can be improved.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a schematic configuration of a dicing apparatus having a visual inspection function of the present invention.

FIG. 2 is a schematic diagram showing an outline of a signal processing system and a control system of the apparatus of FIG.

FIG. 3 is a plan view showing inspection points of a semiconductor wafer.

FIG. 4 (a) shows a state in which a semiconductor wafer after cutting has no chipping or cracking, and FIG. 4 (b) shows a state in which chipping or cracking has occurred. FIG.

FIG. 5 is a schematic plan view similar to FIG. 1 showing a first conventional example.

FIG. 6 is a schematic plan view similar to FIG. 1 showing a second conventional example.

[Explanation of symbols]

 2 semiconductor wafer 3 loading / unloading position 6 alignment position 7 cutting position 10 'XY-θ drive stage 11 dicing blade 12 air curtain 13 semiconductor wafer after cutting 14 loading / unloading wafer standby position 15 wafer cleaning position 18 imaging camera 19 wafer center 22 , 23 Chip corner 25 Calf 26 CPU 27 Drive control unit 28 Image processing unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuaki Hayashi 20-19 Shimizutani-cho, Tennoji-ku, Osaka-shi, Osaka (72) Inventor Katsuharu Negishi 2-14-3 Higashi-Kojiya, Ota-ku, Tokyo

Claims (4)

[Claims] 1. An XY-θ drive stage that is movable in the X-axis direction and the Y-axis direction, is rotatable in a horizontal plane, and moves between an alignment position and a cutting position, and is arranged at the alignment position. An image pickup means for picking up an image of the surface of the semiconductor wafer mounted on the XY-θ drive stage, and an alignment process for recognizing the posture of the semiconductor wafer based on an image pickup signal from the image pickup means and performing an alignment process. Means and the semiconductor wafer, which is arranged at the cutting position and is relatively transferred in the X-axis direction by the XY-θ drive stage, based on the information from the alignment means.
Cutting means for cutting along the street in the axial direction, and imaging means for imaging the surface of the semiconductor wafer after cutting which has been relatively transferred in the X-axis direction to the alignment position by the XY-θ drive stage. A dicing apparatus having an appearance inspection function, which has an appearance inspection means for inspecting the state of each of the semiconductor chips divided based on the image pickup signal. 2. A means for setting the movement amount in the X-axis direction and the Y-axis direction from the cutting line located at the wafer center of the semiconductor wafer after cutting to an arbitrary cutting line, and the movement amount. 2. A dicing apparatus having a visual inspection function according to claim 1, further comprising means for moving the XY-θ drive stage or the image pickup means in the X-axis direction and the Y-axis direction according to the above. 3. The appearance according to claim 1, wherein the appearance inspection means includes means for detecting a kerf width of the semiconductor wafer after the cutting and determining whether the semiconductor chip is good or bad based on the kerf width. Dicing machine with inspection function. 4. The dicing apparatus having a visual inspection function according to claim 1, wherein the visual inspection means has means for reporting a cutting abnormality.