JPH07321072A - Dicing device - Google Patents

Abstract

PURPOSE:To provide a dicing device which can decrease the generation of defective wafers. CONSTITUTION:A wafer 10 fixed on a processing table 17 is subjected to cutting work by a blade 19, which is rotated by a spindle motor 21, and thereafter, the wafer 10 is fixed on a cleaning table 25. The table 25 is rotated and cleaning water is supplied to the wafer 10, whereby the surface of the wafer 10 is cleaned. A pattern of the surface of the wafer 10 subsequent to the cleaning is caught by a dirt inspection microscope 27 provided over the wafer 10 and the image of the pattern is fed to an image processing device. The image processing device compares image data on the surface of the wafer 10 subsequent to this cleaning with previously stored that on the surface of the wafer 10 prior to the cutting and detects a dirt on the surface of the wafer 10. When the detected dirt exceeds a prescribed amount, an NC device changes a cleaning time, a cutting rate and the like to modify a cleaning condition and a cutting condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dicing device.

[0002]

2. Description of the Related Art A dicing machine cuts a rotating blade (blade) into a semiconductor wafer on a processing table,
The wafer is cut into chips by horizontally moving the processing table. This disconnection is automatically performed by the NC device (numerical control device).

[0003] In cutting, since the cutting powder by the blade adheres to the wafer surface, the wafer surface may be washed with water during cutting in order to remove the cutting powder, or a step of cleaning the wafer surface after cutting may be provided in the dicing machine. Then, the generation of defective wafers in which the cutting chips adhere to the surface is prevented.

However, depending on the cutting conditions, the amount of cutting powder is large, and if the cleaning conditions such as the amount of water and the cleaning time are not appropriate, the cutting powder may not be completely removed and may remain on the wafer surface. There is. Therefore, conventionally, after all the processing by the dicing device is completed, an operator looks at the wafer surface with a microscope and inspects the wafer for contamination.

[0005]

However, in the dicing device, since the wafer is continuously processed by the automatic control by the NC device, even if the dirt inspection is performed after the processing by the dicing device, a large amount of defective wafers are already produced. It's gone. The chips adhering to the wafer become difficult to remove when the wafer dries, which lowers the yield and raises the manufacturing cost.

Therefore, an object of the present invention is to provide a dicing apparatus which can reduce the generation of defective wafers.

[0007]

According to the invention of claim 1, in a dicing apparatus for cutting a semiconductor wafer,
Image pickup means for picking up an image of the surface state of the semiconductor wafer, dirt detecting means for detecting dirt on the surface of the semiconductor wafer from the surface state before cutting and the surface state after cutting which are picked up by the image pickup means, and the dirt detecting means. The above object is achieved by providing the dicing apparatus with condition control means for changing the cutting conditions when dirt is detected by the means.

According to a second aspect of the present invention, the dicing apparatus according to the first aspect includes cutting water supply means for supplying cutting water to the surface of the semiconductor wafer at the time of cutting, and the condition control means includes the cutting speed and the cutting speed. The object is achieved by changing the cutting conditions by changing at least one of the amount of cutting water supplied by the cutting water supply means.

According to a third aspect of the present invention, the dicing apparatus according to the first aspect is provided with a wafer cleaning means for cleaning the semiconductor wafer after cutting, and the dirt detecting means has a surface state before cutting and the wafer. Contamination of the surface of the semiconductor wafer is detected from the surface state after cleaning by the cleaning unit, and the condition control unit changes at least one of the cutting condition and the cleaning condition when the contamination is detected by the contamination detection unit. By doing so, the above object is achieved.

According to a fourth aspect of the invention, in the dicing apparatus according to the third aspect, the wafer cleaning means performs cleaning by supplying a cleaning liquid to the surface of the semiconductor wafer while rotating the semiconductor wafer, and the condition control means. The object is achieved by changing the cleaning condition by changing at least one of the rotation speed of the semiconductor wafer by the cleaning means, the cleaning time, and the supply amount of the cleaning liquid.

[0011]

In the dicing apparatus according to claim 1, the image pickup means picks up an image of the surface state of the semiconductor wafer, and the dirt detection means
Contamination on the wafer surface is detected from the surface condition before and after cutting, which is imaged by the imaging means. Then, the condition control means changes the cutting condition when the dirt is detected by the dirt inspection means.

In the dicing apparatus according to the second aspect, the cutting water supply means supplies the cutting water to the surface of the semiconductor wafer at the time of cutting. The condition control means changes the cutting condition by changing at least one of the cutting speed and the amount of cutting water supplied by the cutting water supply means. In the dicing apparatus according to the third aspect, the wafer cleaning means cleans the semiconductor wafer after cutting. The dirt detection unit detects dirt on the surface of the semiconductor wafer from the surface state before cutting and the surface state after cleaning by the wafer cleaning unit, and the condition control unit determines cutting conditions when dirt is detected by the dirt detection unit. And / or change at least one of the washing conditions.

In the dicing apparatus according to the fourth aspect, the wafer cleaning means performs the cleaning by supplying the cleaning liquid to the surface of the semiconductor wafer while rotating the semiconductor wafer. The condition control unit changes the cleaning condition by changing at least one of the rotation speed of the semiconductor wafer by the cleaning unit, the cleaning time, and the supply amount of the cleaning liquid.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the dicing apparatus of the present invention will be described in detail below with reference to FIGS. Figure 1
Shows the arrangement of essential parts when the dicing apparatus of this embodiment is viewed from above.

As shown in this figure, in the dicing apparatus of this embodiment, a stocker 11 that can store wafers 10 before and after cutting and a wafer 10 taken out from the stocker 11 are temporarily placed. A pre-alignment 13 as a positioning table, and a loader 15 for transporting the wafer 10 as shown by an arrow A in FIG. The loading / unloading of the wafer 10 to / from the stocker 11 is performed by a transfer device (not shown).

Further, the dicing apparatus is equipped with a processing table 17 on which the wafer 10 carried by the loader 15 is placed and fixed, and a spindle motor 21 for rotating the blade 19. Processing table 1
7 is horizontally moved as shown by an arrow B, and the spindle motor 21 is moved vertically to the paper surface, that is, in the vertical direction. Then, the processing table 17 is moved to the position shown by the dotted line in FIG. 1 and the spindle motor 21 is lowered, so that the blade 19 is cut into the wafer 10.

Although not shown, the dicing apparatus of the present embodiment is equipped with a cutting water supply device for supplying cutting water to a contact portion between the wafer 10 and the blade 19 from a nozzle provided in the vicinity of the blade 19. There is. As shown in FIG. 1, a positioning microscope 23 for enlarging and observing the pattern on the surface when positioning the wafer 10 is provided on the side of the blade 19. In the positioning microscope 23,
A CCD camera that captures an enlarged image is incorporated, and CC
The image captured by the D camera is supplied to the image processing device (see FIG. 2). The positioning microscope 23 and the spindle motor 21 are fixed on a moving table 24 by a fixing member (not shown) so that they can move integrally in the direction of arrow C.

Further, the dicing apparatus has a cleaning table 25 on which the wafer 10 after cutting is placed. The cleaning table 25 is configured to rotate, and a cleaning water supply nozzle (not shown) for supplying cleaning water is arranged above the cleaning table 25. The cleaning water is supplied from the cleaning water supply nozzle (not shown), and the cleaning table 25 is rotated to clean the surface of the wafer 10. Further, above the cleaning table 25, a dirt inspection microscope 27 equipped with a CCD camera is arranged like the positioning microscope 23, and an image captured by the dirt inspection microscope 27 is an image processing device ( Figure 2
(See reference). The dirt-inspection microscope 27 is designed to move in parallel with the plane of the drawing, that is, to move horizontally, in order to change the imaging position. Although not shown, an air nozzle for drying the cleaned wafer 10 with air is also provided above the cleaning table 25.

FIG. 2 shows a part of the control system of the dicing machine. The dicing device according to the present embodiment is
An NC device 31 for controlling each drive unit such as the loader 15 is provided. That is, a driver 37 for driving the spindle motor 21 and a driver 39 for a drive motor 38 for moving the machining table 17 are connected to the NC device 31, and the rotation speed of the blade 19, the position and movement speed of the machining table 17, etc. are determined. It is designed to be controlled. Also,
A driver 41 of a drive motor 40 for rotating the cleaning table 25 is connected to the NC device 31, and the rotation speed of the cleaning table 25 is controlled by the control of the driver 41. Further, the NC device 31 has the cleaning table 2
By controlling the supply device 45 such as a pump for supplying the cleaning water to the cleaning water supply nozzle 43 arranged on the upper part 5, the amount of the cleaning water and the cleaning time can be adjusted. The amount of cutting water supplied by the cutting water supply device (not shown) is also adjusted by the control of the NC device 31.

As shown in FIG. 2, an image processing device 32 is also connected to the NC device 31. The image processing device 32 analyzes the lightness and darkness of an image captured by the dirt inspection microscope 27 for each pixel, and the dirt inspection is performed by obtaining image data of the surface of the wafer 10 fixed on the cleaning table 25. It has become.

The NC device 31 changes the rotation speed of the blade 19, the moving speed of the processing table 17, the supply amount of cutting water, etc. according to the result of the dirt inspection of the surface of the wafer 10 by the image processing device 32. Change the cutting conditions,
The cleaning conditions are changed by changing the rotation speed of the cleaning table 25, the supply amount of cleaning water, and the like.

An image captured by the positioning microscope 23 shown in FIG. 1 is also supplied to the image processing device 32 via a CCD camera. Next, the operation of the embodiment thus configured will be described. FIG. 3 shows the flow of operations of the dicing device, focusing on the processing performed by the NC device 31.

First, the wafer 10 is taken out from the stocker 11 onto the pre-alignment 13 by a transfer device (not shown), and is placed on the processing table 17 by being transferred by the loader 15. Next, the NC device 31 moves the processing table 17 to the position shown by the dotted line in FIG. 1, and at the same time, images the positioning pattern on the surface of the wafer 10 by the positioning microscope 23, for example. Then, the NC device 31
Moves the moving table 24 and the like while checking the position of the wafer 10 based on the imaged pattern to position the wafer 10 (step 1).

Next, the NC device 31 lowers the magnification of the positioning microscope 23 to widen the image pickup area and moves the moving table 24 and the processing table 17 to change the image pickup position. For example, the positioning microscope 23 is positioned at a position where an image is taken of a portion where the wafer 10 is easily contaminated by cutting, such as a boundary line (street) that divides the wafer 10 into chips. Then, the pattern on the wafer 10 is imaged, and the image processing device 32 stores the image data (step 2).

Next, the NC device 31 rotates the spindle motor 21 at a predetermined number of revolutions, and also the blade 19
The spindle motor 21 is lowered to a position where it is cut into the wafer 10 by a desired depth. And processing table 1
7 and the moving table 24 are moved by a predetermined number of steps to perform a cutting process for dividing the wafer 10 into chips (step 3).

Then, the NC device 31 is connected to the processing table 1
7 is moved to the position shown in FIG. 1 again, and the wafer 10 is placed on the cleaning table 25 by being conveyed by the loader 15.
At this time, the wafer 10 is fixed on the cleaning table 25 by vacuum suction or the like. Then, the cleaning table 25 is rotated at a predetermined speed, the cleaning water is supplied from the cleaning water supply nozzle 43 to the central portion of the wafer 10, and the surface of the wafer 10 is cleaned (step 4).

After the lapse of a predetermined time, the supply of cleaning water is stopped, and air is blown onto the surface of the wafer 10 from an air nozzle (not shown) to dry the wafer 10 (step 5). Next, the NC device 31 moves the dirt inspection microscope 27 to a predetermined position on the wafer 10, and images the pattern similar to the pattern imaged in step 2 with the dirt inspection microscope 27 (step 6). Normal,
Since the same pattern is drawn for each chip on the semiconductor wafer, at this time, the contamination inspection microscope 27 is used for the wafer 10.
It is also possible to move to a plurality of locations above and capture a plurality of patterns.

Then, the image processing device 32 takes a difference between the image data of the pattern imaged at this time and the image data of the pattern stored in step 2, and the remaining image in the difference image is treated as a stain. It is determined whether the total sum is equal to or more than a predetermined amount (step 7). That is, the wafer 10
Inspect the surface for dirt.

When the difference is equal to or more than the predetermined amount (step 7; Y), that is, when the surface of the wafer 10 is contaminated, the image processing device 32 outputs a signal indicating the inspection result to the NC device 31. , NC device 31 based on this signal
Determines whether or not the stain has been detected a predetermined number of times (for example, the third time) (step 8). When the stain is not recognized in step 7 (N), the process proceeds to step 10. On the other hand, in step 8, if the stain detection is not the predetermined time (step 8; N), the cleaning condition and the cutting condition are changed (step 9).

That is, dirt on the surface of the wafer 10 is caused by cleaning conditions such as the flow rate of water, the cleaning time, and the number of rotations of the cleaning table 25 during cleaning (step 4), and the cutting water during cutting (step 3). It depends on cutting conditions such as the amount, the rotation speed of the blade 19, and the moving speed of the processing table 17. Therefore, in this embodiment, for example, the cleaning condition is changed by a predetermined amount by increasing the flow rate of the cleaning water, lengthening the cleaning time, or increasing the rotation speed of the cleaning table 25. Further, by increasing the rotation speed of the blade 19 or decreasing the moving speed of the processing table 17, the contact amount of the blade 19 with respect to the wafer 10 at the time of cutting (in this specification, this is referred to as “cutting”). "Speed") is increased by a predetermined amount. Alternatively, the cutting conditions are changed by increasing the amount of cutting water supplied by a cutting water supply device (not shown).

By changing the above washing conditions and cutting conditions,
With respect to the wafer 10 to be processed thereafter, the cleaning conditions and the cutting conditions are improved, and it is possible to prevent the generation of defective wafers to which cutting dust is attached due to cutting. Then N
The C device 31 returns the wafer 10 on the cleaning table 25 onto the pre-alignment 13 by the loader 15, and
It is stored in the stocker 11 by a transport device (not shown) (step 10).

When the processing of the predetermined number of wafers 10 is completed (step 11; Y), the apparatus is stopped (step 12) and the processing is completed. On the other hand, in step 8, if the stain is detected a predetermined number of times (step 8;
Y) Even if the cleaning condition and the cutting condition are changed a predetermined number of times, the stain has not been improved, and there is a possibility that the stain may be another cause. Therefore, an alarm is output and the apparatus is stopped (step 12). ).

As described above, in the dicing apparatus according to the present embodiment, the contamination inspection of the wafer surface after cleaning is performed, so that the contamination inspection in the next process after the processing by the dicing apparatus can be omitted. it can. In the above embodiment, the pattern of the wafer 10 before cutting (step 4) is stored for each wafer 10. However, when a plurality of wafers 10 of the same type are continuously processed, Alternatively, only the pattern of the first wafer may be stored, and the stain inspection of all other wafers may be performed based on the image data.

In the above embodiment, the wafer contamination inspection is
Although it is performed every time, it may be performed every five sheets, for example. In addition, every time an inspection is performed, the contamination inspection microscope 27 may be horizontally moved to change the inspection position to a position where a similar pattern can be imaged, and contamination inspection of a plurality of wafers may be performed over one stocker. .

Further, in step 9, for example, only the cleaning time may be changed, or one of the cleaning condition and the cutting condition may be changed.

[0036]

According to the dicing apparatus of the present invention, the generation of defective wafers can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a main part of a dicing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system of the device.

FIG. 3 is a flowchart showing a flow of operations of the apparatus.

[Explanation of symbols]

 10 wafer 11 stocker 13 pre-alignment 15 loader 17 processing table 19 blade 21 spindle motor 23 positioning microscope 24 moving table 25 cleaning table 27 dirt inspection microscope 31 NC device 32 image processing device 37, 39, 41 driver 38, 40 drive motor 43 Cleaning Water Supply Nozzle 45 Supply Device

Claims (4)

[Claims] 1. A dicing apparatus for cutting a semiconductor wafer, wherein an image pickup means for picking up an image of a surface state of the semiconductor wafer and the semiconductor state based on a surface state before cutting and a surface state after cutting picked up by the image pickup means. A dicing apparatus comprising: a dirt detecting means for detecting dirt on the surface of a wafer; and a condition control means for changing a cutting condition when the dirt is detected by the dirt detecting means. 2. A cutting water supply unit for supplying cutting water to the surface of the semiconductor wafer at the time of cutting, wherein the condition control unit changes at least one of a cutting speed and a supply amount of cutting water by the cutting water supply unit. The dicing apparatus according to claim 1, wherein the cutting condition is changed accordingly. 3. A wafer cleaning means for cleaning the semiconductor wafer after cutting, wherein the dirt detecting means cleans the surface of the semiconductor wafer according to a surface condition before cutting and a surface condition after cleaning by the wafer cleaning means. 2. The dicing apparatus according to claim 1, wherein the condition control unit changes at least one of a cutting condition and a cleaning condition when the dirt is detected by the dirt detecting unit. 4. The wafer cleaning means performs cleaning by supplying a cleaning liquid to the surface of the semiconductor wafer while rotating the semiconductor wafer, and the condition control means causes the cleaning speed of the semiconductor wafer by the cleaning means and cleaning. The dicing apparatus according to claim 3, wherein the cleaning condition is changed by changing at least one of a time and a supply amount of the cleaning liquid.