JP2002343763A - Centrifugal separator for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal separator for semiconductor wafers that suppresses contamination and cracks in semiconductor wafers in the centrifugal separator for semiconductor wafers for washing the semiconductor wafers and then carrying out dry treatment. SOLUTION: This centrifugal separator for semiconductor wafers has a rotor 2 that is rotated around a specific vertical shaft 1 where a semiconductor wafer (w) is mounted, and a casing 4 for surrounding the rotor 2. An AE sensor 6 is laid in the casing 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a centrifuge for semiconductor wafers.

[0002]

2. Description of the Related Art In the manufacture of a semiconductor wafer, a semiconductor wafer is washed with water in a final step and then dried. A device for performing such a process is a semiconductor wafer centrifuge. Machines have existed for some time.

[0003] This semiconductor wafer centrifugal separator includes a rotating body on which a large number of semiconductor wafers are mounted and rotated around a rotation axis at a specific position, and a casing surrounding the rotating body.

In the use, the rotating body is rotated at a high speed after the semiconductor wafer is mounted on the rotating body, and thereafter, the washing water is poured onto these wafers by a water jet nozzle for an appropriate time. Let it continue. Thereby, during the supply of the cleaning water from the water injection nozzle, the cleaning water is applied to the surface of each semiconductor wafer, and the cleaning water flows outward in the radius of rotation by centrifugal force due to the rotation of the rotating body, and then flows to the casing. When the supply of cleaning water from the water injection nozzle is stopped, the water remaining on the surface of the semiconductor wafer is separated and scattered by centrifugal force,
An air flow is generated around the semiconductor wafer in a direction outward of the rotation radius of the rotating body, and the air flow actively evaporates moisture remaining in each semiconductor wafer.

When the rotating body is rotating at a high speed, the semiconductor wafer may be broken due to vibration or the like, and the small pieces generated at this time are scattered outside the radius of the rotating body by centrifugal force. However, this may collide with the inner surface of the casing and be further crushed into small pieces.If the next semiconductor wafer is mounted on the rotating body without noticing the crushing, these wafers may be contaminated or these wafers may be contaminated. Cracking can occur again, and the effects of the initial crushing are linked one after another. In order to prevent this, a technique for providing a sensor for detecting crushing of the semiconductor wafer and stopping rotation of the rotating body by detecting crushing of the semiconductor wafer has been implemented.

[0006]

However, in a conventional centrifugal separator, a sensor detects vibration (noise) of the casing caused by a phenomenon other than crushing of the wafer, and the rotation of the rotating body is stopped by the noise. Or the semiconductor wafer being processed is crushed, the sensor cannot detect it, and the subsequent processing is continued as it is, contaminating the next mounted semiconductor wafer, or cracking it. May occur. An object of the present invention is to provide a semiconductor wafer centrifuge which can suppress such a situation.

[0007]

In order to achieve the above object, according to the present invention, there is provided a rotating body on which a semiconductor wafer is mounted and which is rotated about a rotation axis at a specific position, and the rotating body. And a casing surrounding the casing, wherein an AE sensor is attached to the casing.

In the above invention, if the semiconductor wafer breaks during rotation of the rotating body, a part of the semiconductor wafer is scattered in the radial direction of rotation by centrifugal force and collides with the inner surface of the casing, and is further finely crushed by the collision. Occurs. At the moment of the collision, an AE signal of a specific frequency is generated in the casing, and the AE signal is detected by the AE sensor, and this detection signal contributes to stopping the rotation of the rotating body.
Since the AE signal is clearly distinguished from the noise signal, unnecessary stopping of the rotating body due to the noise signal detected by the AE sensor is suppressed.

The above invention is embodied as follows. That is,
As described in claim 2, the rotation of the rotating body is stopped in association with the fact that the frequency corresponding to the maximum level value of the AE signal detected by the AE sensor has a value within a specific range. Provide emergency operating means. In this case, as described in claim 3, the specific range is approximately 80 KHZ to
The range is about 150 KHZ. As a result, when a part of the rotating body collides with the casing due to breakage of the semiconductor wafer, the rotation of the rotating body is urgently stopped. However, the rotation is stopped when metal or resin (such as plastic) collides with the casing. It will not be.

According to a fourth aspect of the present invention, the specific range of the maximum level of the AE signal detected by the AE sensor can be changed. According to this, even when the support state of the casing or the use state of the product of the present invention changes, the specific range is changed, and the AE sensor detects a noise signal, thereby causing the rotating body to malfunction. Emergency stop is more strictly prevented.

According to the present invention, the maximum level value of the AE signal detected by the AE sensor falls within a specific range, and the frequency of the maximum level value falls within a specific range. Emergency operating means for operating to stop the rotation of the rotating body.

According to a sixth aspect of the present invention, the specific range of the maximum level value of the AE signal detected by the AE sensor can be changed, and the specific range of the frequency of the maximum level value can be changed. The configuration is as follows. According to this, even when the support state of the casing or the use state of the product of the present invention changes, these specific ranges are changed, so that the semiconductor wafer mounted on the rotating body is cleaned with a cleaning liquid such as water. The emergency stop of the rotating body due to the malfunction caused by the AE signal generated by the collision of the cleaning liquid with the casing is more strictly prevented.

[0013]

1 to 6 relate to a centrifugal separator according to the present invention. FIG. 1 is an overall schematic view, FIG. 2 shows a main part, A is an assembly drawing, and B is a side view thereof. FIG. 3 is a graph showing data when a fragment of the semiconductor wafer collides with the casing, FIG. 4 is a graph showing data when water collides with the casing, and FIG. 5 is a graph showing data when the casing is hit with metal. FIG. 6 is a graph showing data when the casing is hit with plastic.

Reference numeral 1 denotes a rotation support shaft rotatably supported at a specific position, which is rotatably driven by a motor (not shown). Reference numeral 2 denotes a rotating body fixed to the upper end of the rotation supporting shaft 1 concentrically with the shaft 1.
Is attached so as to be able to be inserted and withdrawn at equiangular positions around the rotation center. The carrier 3 is a container for collectively transporting a large number of semiconductor wafers w, and supports a large number of semiconductor wafers w in a horizontally stacked state while being engaged with the rotating body 2.

Reference numeral 4 denotes a metal casing that surrounds the periphery of the rotating body 2. A drain pipe 5 is connected to the bottom surface 4a.
The liquid on a is not leaked downward therethrough, and an opening / closing lid 5 is attached to the upper opening.

A single end type (unbalanced type) AE sensor 6 is attached to the outer peripheral surface of the casing 4. Here, AE is Acoustic Emission
Is an abbreviation of "sound emission", and more specifically, the release of acoustic energy generated when an individual is deformed or destroyed under stress, and is generally several tens of kHz.
It is intended for an ultrasonic range of up to several MHZ. As shown in FIG. 2A, the AE sensor 6 has a cylindrical main body 6a.
And a cable take-out portion 6b protruding laterally from the peripheral surface of the main body 6a, and a cable 6c extending from the take-out portion 6b.
a is about 20mm in diameter and 35m in height
m.

The mounting structure of the AE sensor 6 will be described as follows. That is, the base member 7 having a screw hole c made of a metal plate is positioned at a height b substantially at the center of the vertical length of the semiconductor wafer mounting area of the carrier 3 on the outer peripheral surface of the casing 4. Is adhered densely with an epoxy resin agent ej. The AE sensor 6 is located on the outer surface of the base member 7, and the cylindrical body 6
The detection surface c, which is the front end surface of a, faces the outer surface of the base member 7.

Then, a pressing and positioning means 8 for pressing the detection surface c against the outer surface of the base member 7 and holding the same at a fixed position is mounted. The pressing and positioning means 8 includes a pressing spring 10 inserted inside a cylindrical holder 9 including a rear end surface portion 9a, a cylindrical wall portion 9b, and a flange portion 9c having a through hole d. A U-shaped notch 9e is formed in the peripheral wall of 9b.

When the pressing and positioning means 8 is fixed, the cylindrical wall 9b of the cylindrical holder 9 in which the pressing spring 10 is inserted is externally inserted into the cylindrical main body 6a of the AE sensor 6 and then the flange 9c. A bolt bo is inserted through the through hole d, and its tip is screwed into the screw hole b of the base member 7. At this time, the cable outlet 6b is inserted into the cutout 9e of the cylindrical wall 9b. As a result, the back of the AE sensor 6 is pressed by the pressing spring 10, and the entire detection surface c is stably and densely pressed against a specific position on the outer surface of the base member 7.

Reference numeral 11 denotes a controller to which the cable 6c of the AE sensor 6 is connected.
The AE signal detected by the E sensor 6 is input, and when the frequency corresponding to the maximum level value of the AE signal becomes a value within a predetermined range, the AE signal is recognized and In addition to stopping the operation of the motor that does not operate, the apparatus is provided with emergency operating means 13 that operates to turn on the indicator lamp 12 and sound an alarm (not shown). At this time, the preset specific range is, for example, 80 kHz to 150 kHz, and the numerical value of this set range is arbitrarily changed and adjusted by operating the input member 13 a forming a part of the emergency operating means 13. It is made.

Next, examples of use and operation of the above-mentioned product of the present invention will be described. The opening / closing lid 5 is opened, and in this state, the plurality of carriers 3 that have been washed with water while accommodating a large number of semiconductor wafers w are rotated by the rotating body 3 as shown in FIG.
To a specific position. Thereafter, the opening / closing lid 5 is closed,
A motor (not shown) is operated to rotate the rotation support shaft 1 and the rotating body 2. As a result, the moisture adhering to each carrier 3 and the semiconductor wafer w accommodated therein is separated and scattered by the centrifugal force caused by the rotation of the rotating body 2 and collides with the inner surface of the peripheral wall of the casing 4, and then travels along this inner surface and its bottom surface 4a, from which it flows out of the casing 4 via the drain pipe 5, while the rotating body 2
Is generated, and the flowing air actively evaporates the moisture of the semiconductor wafer w. Thereby, each semiconductor wafer w is dried with high efficiency.

After a lapse of time sufficient for each semiconductor wafer w to dry, the rotation of the rotating body 2 is stopped. After this stop, the opening / closing lid 5 is opened manually or automatically. Then, the carrier 3 on the rotating body 2 is removed, and thereafter, the same processing is repeated.

During use, if the semiconductor wafer w is broken for any reason, a part of the semiconductor wafer w is scattered by the centrifugal force of the rotating body 2 and collides with the inner surface of the peripheral wall of the casing 4.
At this time, the casing 4 generates an AE signal due to the collision. The FFT analysis data of the AE signal is substantially as shown in FIG.

In this data, the horizontal axis is the frequency scale (unit: HZ) of the AE signal, and the vertical axis is A
The scale of the level (unit is dB) of the E signal is used. A and B are vertical cursor lines, and one of the cursor lines matches the maximum level value of the AE signal. Here, the cursor line of B is matched with the maximum level of the AE signal, the level value is -32.20 dB, and the frequency value is 8421.523HZ. The level value of the AE signal whose cursor line A is coincident is -34.0.
At 0 dB, the frequency value is 104210.523HZ. Δ is the absolute value of the difference between the matched frequency value of the cursor line A and the matched frequency value of the cursor line B, the value is 20000.000HZ, and □ is the level of the matched frequency of the cursor line A. The absolute value of the difference between the value and the level value of the matched frequency of the cursor line of B, and the value is 1.80.
dB.

The AE signal resulting from the collision is detected by the AE sensor 6 and transmitted to the controller 11. At this time, the frequency corresponding to the maximum level value of the AE signal is 84210.5523HZ, and this frequency value is Since it is within the specific range set in advance, the emergency operation means 13 operates to stop the rotation of the rotating body 2 and also to turn on the indicator lamp 12 or sound an alarm (not shown).

As a result, the progress of a chain of harmful effects caused by the damage of the semiconductor wafer w is prevented, and the operator can recognize the occurrence of cracks in the semiconductor wafer w. After the rotation of the rotating body 2 is stopped, the operator cleans the inside of the casing 4 and returns to the normal operable state.

By the way, a metal piece or a wood piece may hit the casing 4 during the operation of the product of the present invention. At this time, the casing 4 also generates an AE signal caused by this. FFT for AE signal of
The analysis data is as follows.

That is, when a metal piece hits, the result is substantially as shown in FIG. 4, and for an AE signal caused by hitting a wood piece, it is almost as shown in FIG.
The structure of these data is based on the above data.

Referring to the data shown in FIG. 4, the cursor line B matches the maximum level of the AE signal, the level value is -14.83 dB, and the frequency is 894.73.
68HZ. The AE signal to which the cursor line A is matched has a level value of −28.50 dB and a frequency value of 6842.155HZ. Δ is the absolute value of the difference between the matched frequency value of the cursor line A and the matched frequency value of the cursor line B, and the value is 5947.3687HZ.
And □ is the absolute value of the difference between the level value of the matched frequency of the cursor line A and the level value of the matched frequency of the cursor line B, and its value is 13.67 dB.

Referring to the data shown in FIG. 5, the cursor line B matches the maximum level of the AE signal.
Its level value is -24.98 dB, and its frequency value is 31.
5.7895 HZ. The AE signal to which the cursor line of A is matched has a level value of -67.42 dB,
The frequency value is 55789.4727HZ. Δ is the absolute value of the difference between the matched frequency value of the cursor line A and the matched frequency value of the cursor line B, and its value is 55473.
□ is the absolute value of the difference between the level value of the matched frequency of the cursor line A and the level value of the matched frequency of the cursor line B, and the value is 42.44 dB.

The frequency value corresponding to the maximum level of the AE signal in the FFT analysis data shown in FIGS. 4 and 5 is 894.7368HZ. Since this value does not fall within a predetermined specific range, an emergency The operating means 13 does not stop the rotating body 2, does not turn on the indicator lamp 12, and does not sound an alarm (not shown). Therefore, the rotator 2 is urgently stopped due to cracking of the semiconductor wafer w, but is not stopped when a metal piece or a wood piece hits the casing 4 and continues to rotate.

The above embodiment can be modified as follows. That is, the cleaning liquid injection nozzle n is provided inside the casing 4 above the rotating body 2, and the rotating body 2 is rotated while the rotating body 2 is rotating.
The cleaning liquid such as water is poured into the semiconductor wafer w mounted on the semiconductor wafer w.

When the maximum level value of the AE signal detected by the AE sensor 6 and the frequency corresponding to the maximum level value fall within a predetermined specific range, this is recognized and not shown. In addition to stopping the operation of the motor, the vehicle is provided with emergency operating means 13 which operates to turn on the indicator lamp 12 and sound an alarm (not shown).

At this time, the specific range set in advance is, for example, a range in which the frequency is in a range of approximately 80 kHz to 150 kHz and the maximum level value is approximately -30 dB or more. The numerical value defining the specific range relating to the frequency and the numerical value defining the specific range relating to the maximum level value can be arbitrarily changed and adjusted by operating the input member 13a forming a part of the emergency operating means 13. .

In this modified example, a phenomenon occurs in which the liquid ejected from the cleaning liquid ejecting nozzles n, n is scattered by the centrifugal force due to the rotation of the rotating body 2 and collides with the inner surface of the casing 4 while the rotating body 2 is rotating. At this time, the casing 4 generates an AE signal due to this phenomenon. The FFT analysis data for this AE signal is generally as shown in FIG. 6, and the structure of this data is based on the above data.

Referring to this data, the cursor line of A is coincident with the position of the maximum level of the AE signal, the level value is −50.95 dB, and the frequency value of this level value is 30526.316HZ. . The level of the AE signal whose cursor line B is coincident is -60.
At 37 dB, the frequency value is 137894.734HZ. The value of △ is 107368.4180HZ,
The value of □ is 9.41 dB. AE in this data
The frequency value corresponding to the maximum level of the signal is 894.736.
8HZ, and the maximum level value is −50.95 dB. However, since these values do not fall within a specific range set in advance, the emergency operating means 13 does not stop the rotating body 2 and the indicator light 12 And does not sound an alarm (not shown).

On the other hand, as is clear from the data shown in FIG. 3, the AE signal when the semiconductor wafer w mounted on the rotating body 2 is damaged during the rotation of the rotating body 2 has a frequency corresponding to the maximum level. Is 8421.523HZ,
The maximum level value is -32.20 dB, and since these values are within a specific range set in advance, the emergency operating means 13 stops the rotating body 2 and turns on the indicator lamp 12 to turn on the alarm (not shown). Sounds.

As is clear from the above, the rotating body 2 is stopped urgently when the semiconductor wafer w is cracked, but when the cleaning liquid collides with the casing 4 as well as when the metal piece or the wooden piece hits the casing 4. Even in such a case,
The rotation of the rotator 2 is continued, so that the liquid cleaning process and the drying process of the semiconductor wafer w can be continuously and efficiently performed without stopping the rotator 2 due to malfunction.

[0039]

According to the present invention described above, the following effects can be obtained. That is, according to the first aspect, when the semiconductor wafer is damaged and a part thereof collides with the casing, an AE signal of a specific frequency is generated in the casing at the moment of the collision, and the AE signal is generated by the AE signal. The AE signal is detected by the sensor and contributes to stopping the rotation of the rotating body. Since the AE signal is clearly distinguished from the noise signal, the AE signal is caused by the noise signal detected by the AE sensor. Unnecessary rotation stop of the rotating body due to malfunction can be suppressed.

According to the second aspect, it is possible to prevent a malfunction in which the rotation of the rotating body is stopped due to the collision of metal or resin with the casing. According to the third aspect, the rotating body can be accurately stopped urgently in connection with a part of the semiconductor wafer colliding with the casing due to breakage of the semiconductor wafer.

According to the fourth aspect of the present invention, the AE signal generated in connection with a part of the semiconductor wafer colliding with the casing due to the damage of the semiconductor wafer is delicately changed in an installation state or a use state. However, the emergency stop of the rotating body due to the malfunction of the emergency stop means can be more strictly prevented in response to such a situation.

According to the fifth aspect, even when the semiconductor wafer mounted on the rotating body is cleaned with a cleaning liquid such as water, the rotation of the rotating body is urgently stopped due to the cleaning liquid. Can be prevented.

According to the sixth aspect, when the semiconductor wafer mounted on the rotating body is cleaned with a cleaning liquid such as water, the cleaning liquid collides with the casing to generate AE.
The signal changes slightly depending on the installation state of the casing and the usage state of the cleaning liquid injection nozzle, etc.In response to such changes in the situation, emergency stop of the rotating body due to malfunction of the emergency stop means is properly performed. It can be more strictly blocked.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of a centrifuge according to the present invention.

FIG. 2 shows a main part of the centrifuge, wherein A is an assembly drawing and B is a side view thereof.

FIG. 3 is a graph showing data when a fragment of a semiconductor wafer collides with a casing in the centrifuge.

FIG. 4 is a graph showing data when the casing is hit with metal in the centrifuge.

FIG. 5 is a graph showing data when the casing is hit with a resin in the centrifuge.

FIG. 6 is a graph showing data when water collides with a casing in the centrifuge.

[Explanation of symbols]

 w semiconductor wafer 1 rotation support shaft (specific vertical axis) 2 rotating body 4 casing 6 AE sensor 13 emergency operation means

Claims (6)

[Claims] 1. A semiconductor wafer centrifugal separator comprising a rotating body on which a semiconductor wafer is mounted and rotated about a rotation axis at a specific position, and a casing surrounding the rotating body, wherein an AE sensor is attached to the casing. And a centrifugal separator for semiconductor wafers. 2. An emergency operating means operable to stop rotation of a rotating body when a frequency corresponding to a maximum level value of an AE signal detected by an AE sensor becomes a value within a specific range. 2. The device according to claim 1, wherein
A centrifugal separator for semiconductor wafers as described in the above. 3. The specific range is approximately 80 KHZ to 150 KH.
3. The centrifugal separator for semiconductor wafers according to claim 2, wherein the range is about Z. 4. The centrifugal separator for semiconductor wafers according to claim 2, wherein a specific range relating to a maximum level value of the AE signal detected by the AE sensor can be changed. 5. The rotation of the rotating body is stopped when the maximum level value of the AE signal detected by the AE sensor falls within a specific range and the frequency of the maximum level value falls within a specific range. 2. The centrifugal separator for semiconductor wafers according to claim 1, further comprising an emergency operating means that operates as described above. 6. A specific range relating to a maximum level value of an AE signal detected by an AE sensor is changeable, and a specific range relating to a frequency of the maximum level value is changeable. Item 7. A centrifuge for semiconductor wafers according to item 5 or 6.