JPH07276229A - Semiconductor wafer edge section polishing device - Google Patents

Abstract

PURPOSE:To provide a semiconductor wafer edge section polishing device which can improve polishing work efficiency and a yield. CONSTITUTION:In a polishing device which is provided with a cylindrical rotatable polishing cloth 13 and mechanisms 19, 21 which can hold and rotate a wafer 1 in such a way that a wafer edge face to be polished is in contact with a surface of the polishing cloth and polishes a wafer edge section 2 while rotating the wafer 1, a surface roughness detector 27 which is arranged in such a way that a detection end 29 is in proximity to the wafer edge section 3 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer edge polishing apparatus for polishing an edge of a silicon wafer or the like.

[0002]

2. Description of the Related Art If the edge of the outer peripheral surface of a wafer is sharp or the surface roughness is rough, minute tips of surface irregularities are chipped during wafer handling, and chipping or fine dust is likely to occur. Such dust is scattered and pollutes the environment such as a clean room. For this reason, the outer peripheral surface of the wafer is an arc surface which is smooth also in the thickness direction of the wafer, and the surface roughness thereof is required to be a so-called mirror surface finish of 0.1 μm R _max or less.

Since the polishing ability of the polishing material of the polishing apparatus decreases as the polishing operation is performed, the polishing operation time gradually increases.
Therefore, the surface roughness of the surface of the edge part is measured, and the polishing result is reflected in the polishing work so that the polishing work is performed by changing the working time and processing conditions so as to maintain the required surface roughness of the edge part. ing.

In the conventional polishing work, a part of the sample wafer taken out at an appropriate time was cut out and used as a measurement sample. With respect to the measurement sample, the surface roughness of the wafer edge portion was compared and observed with a limit sample with a scanning electron microscope, a surface roughness meter, or the like, and the replacement time of the abrasive was determined by measuring.

[0005]

As described above, conventionally, a measurement sample is cut out from a sample wafer in order to measure the surface of the wafer edge portion. For this reason, it took a long time to obtain the measurement result of the surface roughness. If the polishing operation is interrupted until the measurement result is obtained, the work efficiency decreases.

Further, when the polishing cloth is damaged or the amount of abrasive grains supplied becomes unstable, if the polishing work is continued without noticing these abnormalities, a large amount of rejected products may be produced. . Furthermore, the sample wafer from which the measurement sample has been cut out cannot be shipped as a product, and therefore has been scrapped. For these reasons, the yield is reduced.

The present invention is intended to provide a semiconductor wafer edge portion polishing apparatus capable of improving the polishing work efficiency and the yield.

[0008]

A semiconductor wafer edge polishing apparatus according to a first aspect of the present invention comprises a rotatable cylindrical polishing cloth,
In a polishing apparatus that has a mechanism capable of holding and rotating a wafer so that the wafer edge surface to be polished is in contact with the surface of a polishing cloth, and a polishing device that polishes the wafer edge portion while rotating the wafer, the detection end is close to the wafer edge portion The surface roughness detector thus arranged is provided.

As the polishing means, a polishing wheel to which a normal polishing cloth is attached, a polishing disk, a polishing belt and the like are used. A vacuum chuck rotatably supported is suitable as the wafer holding means. The polishing means and the wafer holding means are rotationally driven by a motor with a speed reducer or the like. A laser interferometer surface roughness detector, a reflection type laser displacement meter, etc. are used as the surface roughness detecting device. These surface roughness detectors can detect the surface roughness without contacting the surface of the edge portion.

The above apparatus may be provided with means for comparing a preset reference surface roughness with a detected value of the surface roughness. An analog or digital comparison circuit or a computer is used as the comparison means.

A semiconductor wafer edge polishing apparatus according to a second aspect of the present invention includes a rotatable cylindrical polishing cloth and a mechanism capable of holding and rotating a wafer so that the wafer edge surface to be polished contacts the surface of the polishing cloth. In the polishing apparatus for polishing the wafer edge portion while rotating the wafer, the surface roughness detector is arranged so that the detection end is close to the wafer edge portion, and the surface roughness is detected based on the signal from the surface roughness detector. And means for calculating the reduction amount of the height.

The polishing means, the wafer holding means, and the surface roughness detector are the same as those of the apparatus of the first invention. A means for comparing the reduction amount of the surface roughness with a preset reference reduction amount may be provided. An analog or digital arithmetic circuit, a comparison circuit, or a computer is used as the arithmetic means and the comparison means.

In the semiconductor wafer edge polishing apparatus according to the first and second aspects of the present invention, there are provided a housing for accommodating the surface roughness detector and covering a part of the wafer edge, and a housing for the wafer edge to enter. It is desirable to provide an air nozzle for injecting air to the wafer edge portion in order to remove water on the wafer surface at the inlet. Further, a swinging mechanism for swinging the body of the surface roughness detector may be provided so that the detection end of the surface roughness detector scans the wafer edge portion in a wave shape along the wafer circumferential direction. A crank or cam is used as the swing mechanism.

[0014]

The semiconductor wafer edge polishing apparatus of the first invention polishes the wafer edge while rotating the wafer,
During the wafer polishing, the surface roughness detector detects the surface roughness of the wafer edge portion in a non-contact manner.

In the apparatus provided with the means for comparing the reference surface roughness and the detected value of the surface roughness, the polishing operation can be automatically terminated when the reference surface roughness is polished. Further, when the reference surface roughness is not reached within a preset reference polishing time, a mechanism for issuing a warning to replace the polishing cloth or automatically replacing the polishing cloth may be provided.

The semiconductor wafer edge polishing apparatus of the second invention detects the surface roughness during wafer polishing as in the first invention. The detected surface roughness is input to the calculating means from the surface roughness detector, and the calculating means calculates the decrease amount of the surface roughness.

In the apparatus provided with the means for comparing with the reference reduction amount, as in the first aspect of the invention, it is possible to provide a mechanism for issuing a warning to replace the polishing cloth or automatically changing the polishing cloth.

In the above-mentioned first and second devices, the device having the housing protects the surface roughness detector from the scattering of the polishing liquid and the polishing powder. Further, the air nozzle removes the polishing liquid and the polishing powder adhering to the surface of the wafer edge portion by jetting the pressurized air, and prevents a measurement error due to contamination of the surface of the wafer edge portion. In an apparatus equipped with a rocking mechanism, the rocking mechanism detects the surface roughness in a wavy shape along the wafer circumferential direction.
A lot of data can be obtained in the thickness direction of the wafer edge portion. Therefore, the polishing work can be managed with higher accuracy.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the first invention.
The silicon wafer edge polishing apparatus is provided with a polishing wheel 11
A polishing cloth 13 is attached to the main body 12 of the above, and the polishing wheel 11 is rotationally driven by a motor 15 with a speed reducer.
A polishing liquid supply nozzle 17 is arranged toward the edge portion 3 of the silicon wafer 1 which is in contact with the polishing wheel 11.

A vacuum chuck 19 is arranged adjacent to the polishing wheel 11, and the vacuum chuck 19 is rotationally driven by a motor 21 with a speed reducer. The vacuum chuck 19 holds the silicon wafer 1 so that the wafer surface 2 is perpendicular to the rotation axis.

A housing 23 is arranged on the side opposite to the polishing wheel 11. An opening 24 is provided in the lower portion of the housing 23, and the edge portion 3 of the silicon wafer 1 passes through the housing 23 through the opening 24.
An air nozzle 25 is arranged on the opening entrance side of the housing 23. Pressurized air is supplied to the air nozzle 25 from a pressurized air source (not shown).

A reflection laser type surface roughness detector 27 is arranged in the housing 23. The detection end 29 of the surface roughness detector 27 is close to the wafer edge portion 3. The surface roughness detector 27 is connected to the computer 3 via the amplifier 31.
Connected to 2.

In the polishing apparatus configured as described above, the polishing wheel 11 and the vacuum chuck 19 are rotated, and the polishing liquid is supplied from the polishing liquid supply nozzle 17 to the wafer edge portion 3 while polishing the wafer edge portion 3. The pressurized air jetted from the air nozzle 25 removes the polishing liquid and polishing powder adhering to the surface of the wafer edge portion to form a clean surface. Then, the surface roughness detector 27 in the housing 23 detects the surface roughness of the wafer edge portion 3 in a non-contact manner.
The detected surface roughness is displayed on the display device 33.

FIG. 2 shows an embodiment of the second invention. It should be noted that the same reference numerals are given to the same devices and members as those shown in FIG. 1, and the description thereof will be omitted. A guide plate 36 of the swing mechanism 35 is fixed in the housing 23, and an arc-shaped guide groove 37 is provided in the guide plate 36. The pin 39 provided on the oscillating plate 38 to which the detector body 28 of the surface roughness detector 27 is fixed has the guide groove 3
It fits in 7. A motor is connected to the rocking plate 38 via a crank mechanism, and the detector body 28 rocks along the guide groove 37 by driving the motor.

The surface roughness detector 27 is connected to a computer 32 via an amplifier 31. Computer 32
Are connected to the display device 33.

In the apparatus constructed as described above, the swinging mechanism 35 is driven to swing the detector 27, and the detecting end 2
Wafer edge part 3 as 9 draws a sine-shaped curve
Is scanned to detect the surface roughness. The detected surface roughness is input to the computer 32 via the amplifier 31.
The computer 32 compares the reference surface roughness set in advance with the surface roughness detection value. The result is displayed on the display device 33. Then, when the wafer edge portion 3 is polished to the reference surface roughness, the polishing wheel 11 is stopped and the polishing operation is finished. If the reference surface roughness is not reached within the reference polishing time, a warning is issued to replace the polishing cloth 13.

[0027]

According to the present invention, the surface roughness of the wafer edge portion can be measured inline during the polishing operation of the semiconductor wafer. Therefore, the time for measuring the surface roughness can be shortened and the measurement result can be immediately fed back to the polishing work, so that the work efficiency and the yield can be improved.

[Brief description of drawings]

FIG. 1 shows an embodiment of the first invention, and is a block diagram of a semiconductor wafer edge portion polishing apparatus.

FIG. 2 shows an embodiment of the second invention and is a configuration diagram of a semiconductor wafer edge portion polishing apparatus.

[Explanation of symbols]

 1 Semiconductor Wafer 2 Wafer Surface 3 Wafer Edge 11 Polishing Wheel 12 Main Body 13 Polishing Cloth 15 Polishing Wheel Driving Motor 19 Vacuum Chuck 21 Vacuum Chuck Driving Motor 23 Housing 24 Opening 25 Air Nozzle 27 Surface Roughness Detector 29 Detecting End 31 Amplifier 32 computer 33 display device 35 swing mechanism 36 guide plate 37 guide groove 38 swing plate

Claims (6)

[Claims] 1. A wafer edge portion provided with a rotatable cylindrical polishing cloth and a mechanism capable of holding and rotating the wafer so that a wafer edge surface to be polished contacts the surface of the polishing cloth. A polishing apparatus for polishing a semiconductor wafer edge part, comprising a surface roughness detector arranged so that a detection end is close to a wafer edge part. 2. The semiconductor wafer edge polishing apparatus according to claim 1, further comprising means for comparing a preset reference surface roughness with a surface roughness detection value. 3. A rotatable polishing cloth, and a mechanism capable of holding and rotating the wafer so that the wafer edge surface to be polished contacts the surface of the polishing cloth, and the wafer edge portion is rotated while rotating the wafer. In the polishing apparatus for polishing, the surface roughness detector is arranged such that the detection end is close to the wafer edge portion, and means for calculating the decrease amount of the surface roughness based on the signal from the surface roughness detector. A semiconductor wafer edge polishing apparatus provided. 4. The semiconductor wafer edge polishing apparatus according to claim 3, further comprising means for comparing the reduction amount of the surface roughness with a preset reference reduction amount. 5. A housing for accommodating a surface roughness detector and covering a part of the wafer edge portion, and air for adhering the wafer edge portion to remove water on the wafer surface at the entrance of the housing into which the wafer edge portion enters. The semiconductor wafer edge portion polishing apparatus according to claim 1, further comprising an air nozzle for jetting. 6. A swing mechanism for swinging the main body of the surface roughness detector so that the detection end of the surface roughness detector scans the wafer edge portion in a wave shape along the wafer circumferential direction. The semiconductor wafer edge portion polishing apparatus according to 1 or 3.