JP2003007806A - Wafer supporting method and mechanism for mounting wafer and semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the possibility of generating cracks on a wafer due to a notch. SOLUTION: The position of the wafer 2 is determined in order that the notch 2a forms the predetermined angle against a supporting point 4 for supporting the wafer 2. The predetermined angel is set to one fourths of the angle at the adjoining supporting point 4. In the case of four-point suspension, the angle is 22.5 degrees against the supporting point 4, and in the case of three-point suspension, the angle is 30 degrees against the supporting point 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of supporting a wafer used in semiconductor manufacturing, and more particularly to a method of supporting a wafer provided with a positioning notch and a mounting mechanism for such a wafer.

[0002]

2. Description of the Related Art The size (diameter) of a silicon wafer used as a substrate for semiconductor manufacturing tends to increase in order to increase the number of semiconductor chips formed per sheet. Currently, a wafer having a diameter of 12 inches (about 300 mm) is used.

Conventionally, a silicon wafer having a diameter of 8 inches (about 200 mm) is provided with a flat portion, which is usually referred to as an original flat, as a mark for recognizing the crystal orientation on a part of the outer circumference. In recent years, notches (notches) are provided instead of orientation flats in order to effectively use the area of the wafer. The notch shape is defined as a standard shape, with a cutting angle of about 90 degrees and a cutting depth of about 1 mm from the outer circumference of the wafer.
(Rounded) is attached.

[0004]

When carrying a wafer,
Alternatively, when the wafer is placed in the processing apparatus, the wafer is supported by the support mechanism. For example, when mounting a wafer on the wafer mounting table in the processing apparatus, first mount the wafer on the lifter pins protruding from the mounting surface of the mounting table, and then lower the lifter pins to place the wafer on the mounting surface. Place on.

Usually, the lifter pins are composed of three or four pins which are arranged at equal intervals on the circumference of the inner circumference of the wafer by a predetermined distance. Therefore, the wafer on the lifter pins is supported by three-point or four-point support.

As described above, in recent years, the diameter of the wafer has increased and the thickness of the wafer has also become extremely thin. When such a wafer is supported by three-point or four-point support, the portion between the support points is bent. When the bending occurs, shear stress is generated in the wafer, but when the notch as described above is provided on the outer periphery of the wafer, the stress is concentrated near the notch. As a result, there is a problem that the wafer may slip starting from the notch.

The present invention has been made in view of the above points, and provides a wafer supporting method, a wafer mounting mechanism, and a semiconductor manufacturing apparatus capable of reducing the possibility that a wafer will slip due to a notch. The purpose is to provide.

[0008]

In order to solve the above problems, the present invention is characterized by taking the following means.

The invention according to claim 1 is a wafer supporting method for supporting a semiconductor wafer by a plurality of supporting points, wherein a notch provided on the outer periphery of the semiconductor wafer is at a predetermined position with respect to the supporting point. Thus, the semiconductor wafer is positioned with respect to the support point.

The invention according to claim 2 is the method for supporting a wafer according to claim 1, wherein the supporting points are arranged at equal intervals along a predetermined circumference, and the notches of the semiconductor wafer are supported by the supporting points. It is characterized by being arranged at a predetermined angle from one of the points.

The invention according to claim 3 is the method for supporting a wafer according to claim 2, wherein the predetermined angle is generated in the wafer at the notch portion when the semiconductor wafer is supported by the supporting mechanism. It is characterized in that the angle is set so that the shear stress to be applied is substantially minimized.

According to a fourth aspect of the present invention, in the wafer supporting method according to the third aspect, the predetermined angle is 1/4 of an angle formed by two adjacent support points. It is a feature.

According to a fifth aspect of the present invention, in the wafer supporting method according to the first aspect, the notch is positioned with respect to the support point by a transfer mechanism for transferring the semiconductor wafer onto the support point. It is characterized by performing in.

According to a sixth aspect of the present invention, there is provided the wafer supporting method according to the sixth aspect, wherein the transfer mechanism is a fork mechanism having a rotating arm, and the semiconductor wafer is held by the fork, and a rotation center of the rotating arm. Move the fork to
The wafer mounting portion provided at the center of rotation is lifted to lift the semiconductor wafer, and the notch is located at a predetermined position with respect to the fork, and the fork is rotated,
It is characterized in that the wafer mounting portion is lowered to hold the semiconductor wafer by the fork, and the fork is moved onto the support point to support the semiconductor wafer at the support point.

According to a seventh aspect of the present invention, there is provided a wafer mounting mechanism for mounting a semiconductor wafer, wherein the wafer supporting mechanism supports the semiconductor wafer at a plurality of supporting points, and the semiconductor wafer is held by a holding section. While the transfer mechanism for transferring to the wafer support mechanism and the position of the notch provided on the outer periphery of the semiconductor wafer are at a predetermined position with respect to the holding portion of the transfer mechanism, the angle of the semiconductor wafer is adjusted. And a rotary positioning mechanism for adjusting the position.

The invention according to claim 8 is the wafer mounting mechanism according to claim 7, wherein the transfer mechanism is a fork mechanism having a rotary arm, and the rotary positioning mechanism is a rotation center of the rotary arm. It is characterized in that it is constituted by a vertically movable wafer mounting portion provided on the above and a rotating mechanism of the rotating arm.

The invention according to claim 9 is the wafer mounting mechanism according to claim 7 or 8, wherein the semiconductor wafer is transferred to the wafer supporting mechanism at a predetermined position of the notch with respect to the holding portion. It is characterized in that it is determined in advance based on the position of the notch when it is opened.

According to a tenth aspect of the present invention, in the wafer mounting mechanism according to the ninth aspect, the position of the notch when the semiconductor wafer is supported by the wafer supporting mechanism is:
It is characterized in that the angular position is such that the shear stress generated in the wafer is substantially minimized in the notch portion.

According to an eleventh aspect of the present invention, in the wafer mounting mechanism according to the tenth aspect, the plurality of supporting points are arranged at equal intervals on the circumference, and the notches of the semiconductor wafer are the supporting points. It is characterized in that the semiconductor wafer is placed on the support points so that they are arranged at a predetermined angle from one of the points.

According to a twelfth aspect of the present invention, in the wafer mounting mechanism according to the eleventh aspect, the predetermined angle is 1/4 of an angle formed by two adjacent support points. It is characterized by.

According to a thirteenth aspect of the present invention, there is provided a semiconductor manufacturing apparatus for processing a semiconductor wafer, wherein the wafer supporting mechanism supports the semiconductor wafer by a plurality of supporting points, and the semiconductor wafer is held by a holding section. The angular position of the semiconductor wafer is adjusted so that the transfer mechanism to be transferred to the wafer support mechanism and the position of the notch provided on the outer periphery of the semiconductor wafer are at a predetermined position with respect to the holding portion of the transfer mechanism. And a rotary positioning mechanism for adjusting.

According to a fourteenth aspect of the present invention, in the semiconductor manufacturing apparatus according to the thirteenth aspect, the transfer mechanism is a fork mechanism having a rotary arm, and the rotary positioning mechanism is provided at a center of rotation of the rotary arm. It is characterized in that it is configured by a wafer mounting part which can be raised and lowered and a rotating mechanism of the rotating arm.

According to a fifteenth aspect of the present invention, in the semiconductor manufacturing apparatus according to the thirteenth or fourteenth aspect, the semiconductor wafer is transferred to the wafer support mechanism at a predetermined position of the notch with respect to the holding portion. It is characterized in that it is predetermined based on the position of the notch at that time.

The invention according to claim 16 is the semiconductor manufacturing apparatus according to claim 15, wherein the position of the notch when the semiconductor wafer is supported by the wafer supporting mechanism is within the wafer at the notch portion. It is characterized in that it is at an angular position such that the shear stress generated in the is substantially minimized.

According to a seventeenth aspect of the present invention, in the semiconductor manufacturing apparatus according to the sixteenth aspect, the plurality of support points are arranged at equal intervals on the circumference, and the notches of the semiconductor wafer are the support points. The semiconductor wafer is mounted on the support point so that the semiconductor wafer is arranged at a predetermined angle from one of the above.

According to an eighteenth aspect of the present invention, in the semiconductor manufacturing apparatus according to the seventeenth aspect, the predetermined angle is 1/4 of an angle formed by two adjacent support points. It is a feature.

According to the above-mentioned invention, when the semiconductor wafer is supported by the wafer support mechanism, the shear stress generated near the notches of the semiconductor wafer supported by the plurality of support points can be minimized. As a result, it is possible to prevent the semiconductor wafer from slipping due to the stress concentration on the notch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

The present inventor simulated the displacement of the semiconductor wafer and the shear stress generated in the wafer when the semiconductor wafer was supported by a plurality of supporting points. As a result, it was found that when the semiconductor wafer was supported by a plurality of supporting points, a constant distribution of the shear stress intensity was generated.

In the simulation, 12 inches
It is assumed that the above notch is provided on the outer periphery of the wafer (about 300 mm). Then, when such a wafer was supported by three-point support and four-point support, the displacement (deflection amount) and shear stress distribution of the entire wafer were obtained. The diameter of the pitch circle where the supporting points are arranged is 212 mm.
Then, it is assumed that four support points are arranged at equal intervals (that is, at equal angles) on the pitch circle.

The wafer is an extremely thin material and gravity causes deflection between the support points. Therefore, the amount of deflection (displacement) of the entire wafer was obtained by simulation. In this case, the amount of deflection is a value obtained by determining how much the wafer is displaced downward or upward from the planar state in units of microns (μm). Deflection on the outer circumference of the wafer in the direction of gravity, that is, downward deflection is greatest at the center position between the support points.

In the case of four-point support, the angular interval between the support points is 90.
The support points are 0 degrees, 90 degrees, 180 degrees,
When it is arranged at a position of 270 degrees, it is a position of 45 degrees which is between 0 degrees and 90 degrees, and a position which is between 90 degrees and 180 degrees 13
5 degree position, 225 degree position which is between 180 degree and 270 degree, and 315 between 270 degree and 360 degree (0 degree)
The downward displacement is greatest in the outer peripheral portion at the position of degree. When viewed between 0 and 90 degrees, the amount of deflection becomes maximum at the position of 45 degrees.

The shear stress distribution was obtained based on the above displacement data. FIG. 1 is a graph showing the shear stress in the outer peripheral portion of the wafer under the above conditions. Since the shear stress has a symmetrical distribution with respect to each support point, FIG. 1 shows only the range from 0 to 45 degrees.

As shown in FIG. 1, the shear stress becomes maximum at 0 degree. This is because both sides bend at the position of the support point. The shear stress decreases as the angle increases, and becomes the minimum near 22.5 degrees. The vicinity of 22.5 degrees is an inflection point at which the curve of the bending increase rate changes from the upward convex curve to the downward convex curve. That is, it was found that the shear stress decreases at the inflection point of the rate of increase in displacement.

The above is an example of the case where the number of supporting points is four, but the same simulation was performed when three supporting points were arranged on the same pitch circle, and the results shown in FIG. 2 were obtained.

When there are three support points, the angle between the support points is 1
Since it is 20 degrees, in FIG.
The range from 60 degrees to 60 degrees is shown. That is, in the case of three support points, the downward displacement is maximum at a position of 60 degrees in the middle of the support points. In this case, the inflection point of the bending increase rate is around 30 degrees, which is half of 60 degrees. Therefore, the shear stress at the outer peripheral portion of the wafer becomes the smallest near 30 degrees.

Summarizing the results of the above-mentioned examination of the shear stress, it can be seen that the shear stress in the outer peripheral portion of the wafer becomes the minimum at an angle ¼ of the angle between the support points.
Moreover, it is estimated that the same result will be obtained even if the number of support points is increased.

FIG. 3 is a diagram showing a case where the wafer 2 is positioned on the support point 4 so that the notches 2a are at the 0-degree position and the 22.5-degree position in the above-mentioned four-point support. The notch 2a shown in FIG. 3 is shown larger than it actually is.

When the notch 2a is arranged at a position of 0 degree as shown in FIG. 3 (a), the notch 2a is located at the portion where the shear stress is maximum. Therefore, the shear stress concentrated in the notch 2a (0.0273 kgf / mm
² ) also becomes large, and slip may occur from the notch 2a as a starting point.

On the other hand, as shown in FIG. 3B, the notch 2a
Is located at a position of 22.5 degrees, the notch 2a is located at the portion where the shear stress is minimum. The shear stress (0.0097 kgf / mm ² ) in this case is 64.5% lower than that shown in FIG. 3A, and therefore the shear stress concentrated in the notch 2a is small.
The possibility of slipping starting from the notch 2a is extremely small.

Similarly, FIG. 4 is a diagram showing a case where the wafer 2 is positioned on the supporting point 4 so that the notches 2a are at the 0-degree position and the 30-degree position in the above-described three-point support. The notch 2a shown in FIG. 4 is shown larger than it actually is.

When the notch 2a is arranged at a position of 0 degree as shown in FIG. 4 (a), the notch 2a is located at a portion where the shear stress is maximum. Therefore, the shear stress concentrated on the notch 2a (0.0531 kgf / mm
² ) also becomes large, and slip may occur from the notch 2a as a starting point.

On the other hand, as shown in FIG. 4B, the notch 2a
When is placed at a position of 30 degrees, the notch 2a is located at the portion where the shear stress is minimum. The shear stress (0.0219 kgf / mm ² ) in this case is as shown in FIG.
The value is 58.0% lower than that in the case shown in (a). Therefore, the shear stress concentrated in the notch 2a is also small, and the possibility of slipping starting from the notch 2a is extremely small.

As described above, if the wafer is supported by the supporting mechanism so that the notch of the wafer is positioned at an angle ¼ of the angle between the support points, the occurrence of slip due to stress concentration at the notch is prevented. can do.

For example, when there is only one processing chamber for processing a wafer, it is preset so that the notch of the wafer is at a fixed position in order to supply it to the transfer system for supplying the wafer to the processing chamber. deep. For example, the notch is set in advance so that the notch is located at a predetermined position when the wafer is stored in the cassette of the transfer system. Since the transfer operation and the transfer operation of the wafer in the transfer system are constant operations, the position of the notch of the wafer when finally placed on the mounting table of the processing chamber is in the state of being accommodated in the cassette. Is uniquely determined by the position of the notch (that is, the predetermined position described above).
Therefore, when the lifter pins (constituting the support points) on the mounting table and the notches of the wafer are housed in the cassette so that the angular positions have the angular positional relationship of 1/4 of the angle between the support points as described above. The position of the notch of the wafer may be set in advance.

Further, even in the case of a multi-chamber structure in which one wafer is continuously processed by a plurality of processing chambers, the positions of the notch and the lifter focus can be determined by the same method. However, the positions of the lifter pins in the second and subsequent processing chambers need to be set in advance at the design stage in consideration of the position of the notch of the wafer in the immediately preceding processing chamber.

However, in the case where the position of the lifter pin cannot be taken into consideration in the design stage in the multi-chamber configuration, or the position cannot be changed by the existing system, a rotary positioning mechanism for rotating the wafer to adjust the position of the notch can be provided. Correspond.

FIG. 5 is a diagram for explaining an example of the rotary positioning mechanism. The fork mechanism 6 shown in FIG. 5 is a fork mechanism (transfer mechanism) including a robot arm for transferring a wafer to a mounting table in the processing chamber.

When changing the position of the notch, first, the wafer 2 is held by the fork 10 provided at the tip of the arm 8 (FIG. 5A), and the wafer 2 is rotated by the rotating shaft 1 of the arm 8.
It moves to a position right above the mounting table 14 provided on the top of 2 (FIG. 5 (b)). Next, the mounting table 14 is moved upward, and the wafer 2 supported by the fork 10 is lifted (FIG. 5C). In this state, since the wafer 2 is separated from the fork 10, the arm 8 is driven to rotate only the fork 10 by a predetermined angle (FIG. 5 (d)). The predetermined angle of each piece is obtained in advance based on the position of the notch when held on the fork 10 in FIG. 5A and the position of the supporting point in the wafer supporting mechanism in the processing chamber for supplying the wafer.

After rotating the fork by a predetermined angle, the mounting table 14 is moved downward, and the wafer 2 is again moved to the fork 10.
Hold (FIG. 5 (e)). And fork 10
To the position shown in FIG. 5 (b) (FIG. 5 (f)). Figure 5
By comparing the positions of the notches 2a in (b) and FIG. 5 (f), it can be seen that the positions of the notches have moved.

Thereafter, by inserting the fork 10 into the processing chamber and supplying the wafer 2 to the wafer supporting mechanism in the processing chamber, the notch can be arranged at a desired position with respect to the supporting point. The rotation operation of the fork 10 shown in FIG. 5 (f) is not always necessary.
The operation to the processing chamber may be started from the state of (e).

As described above, the rotary positioning mechanism shown in FIG. 5 is composed of the transfer mechanism including the fork mechanism and the mounting table 14 provided on the rotary shaft 12 of the arm 8. Therefore, the wafer can be easily rotated without using a complicated rotation mechanism or positioning mechanism.

FIG. 6 is a schematic plan view showing the structure of a semiconductor manufacturing apparatus 20 provided with a transfer mechanism according to the present invention. The fork mechanism (transfer mechanism) shown in FIG. 5 is arranged in the transfer chamber 22. The transfer chamber 22 has a load lock chamber (L / L)
24 and the semiconductor processing devices 26 and 28 are connected. A fork mechanism provided in the transfer chamber 22 places the semiconductor processing apparatus 26 or 28 in the semiconductor processing apparatus 26 and performs predetermined processing. At this time, the fork mechanism rotates and adjusts the semiconductor wafer so that the notch of the semiconductor wafer mounted on the wafer support mechanism in the semiconductor processing apparatus 26 or 28 has a predetermined positional relationship.

FIG. 7 is a sectional view of the semiconductor processing apparatus 26 shown in FIG. The semiconductor processing apparatus 26 includes a processing chamber 30.
And performs a predetermined process on the semiconductor wafer W placed in the process chamber 30. A mounting table 32 is arranged in the processing chamber 30, and a shower head 34 for supplying a processing gas is provided above the mounting table 32.

A gate valve 36 is provided on the side surface of the processing chamber 30, and the semiconductor wafer W is transferred from the transfer chamber through the gate valve 36 to the mounting table 3 in the processing chamber 30.
2 is placed on. At this time, the three or four lifter pins 38 extending through the mounting table 32 ascend and the semiconductor wafer W is first supported on the lifter pins 34. The notch of the semiconductor wafer W has the lifter pin 3 by the above method.
4 is placed on the lifter pin 34 after being rotated by the fork mechanism so as to be in a predetermined position with respect to 4.

Therefore, the semiconductor wafer can be placed so that the notch of the semiconductor wafer W is at the position where the shear stress is the lowest, and the slip generated in the semiconductor wafer W due to the stress concentration on the notch can be prevented. You can

As described above, according to the present invention, when the semiconductor wafer is supported by the wafer support mechanism, the shear stress generated near the notches of the semiconductor wafer supported by the plurality of support points is minimized. You can
As a result, it is possible to prevent the semiconductor wafer from slipping due to the stress concentration on the notch.

[Brief description of drawings]

FIG. 1 is a graph showing shear stress in a peripheral portion of a wafer supported by four points.

FIG. 2 is a graph showing shear stress in a peripheral portion of a wafer supported by three points.

FIG. 3 shows a four-point support in which the notch has a position of 0 degree and 2
It is a figure which shows the case where it positions so that it may become a position of 2.5 degrees.

FIG. 4 shows a three-point support in which a notch has a position of 0 degree and
It is a figure which shows the case where it positions so that it may become a position of 0 degree.

FIG. 5 is a diagram for explaining an example of a rotary positioning mechanism.

FIG. 6 is a schematic plan view showing the configuration of a semiconductor manufacturing apparatus provided with a transfer mechanism according to the present invention.

7 is a sectional view of the processing apparatus shown in FIG.

[Explanation of symbols]

2 Semiconductor wafer 2a notch 4 Support points 6 Fork mechanism 8 arms 10 forks 12 rotation axes 14 Mounting table 20 Semiconductor manufacturing equipment 22 Transfer room 24 Road lock room 26,28 Semiconductor processing equipment 30 processing chamber 32 table 34 shower head 36 gate valve 38 Lifter Pin

Claims (18)

[Claims] 1. A wafer supporting method for supporting a semiconductor wafer by a plurality of supporting points, wherein the notch provided on the outer periphery of the semiconductor wafer is at a predetermined position with respect to the supporting point. A method for supporting a wafer, wherein the wafer is positioned with respect to the support point. 2. The wafer supporting method according to claim 1, wherein the support points are arranged at equal intervals along a predetermined circumference, and the notches of the semiconductor wafer are provided from one of the support points by a predetermined distance. A method for supporting a wafer, characterized in that the wafers are arranged at an angle. 3. The wafer supporting method according to claim 2, wherein a shear stress generated in the wafer at the notch portion when the semiconductor wafer is supported by the supporting mechanism at the predetermined angle is substantially the same. A method for supporting a wafer, characterized in that the angle is set so as to be minimum. 4. The wafer supporting method according to claim 3, wherein the predetermined angle is ¼ of an angle formed by two adjacent support points. . 5. The wafer supporting method according to claim 1, wherein the positioning of the notch with respect to the support point is performed by a transfer mechanism for transferring the semiconductor wafer onto the support point. Wafer supporting method. 6. The wafer supporting method according to claim 6, wherein the transfer mechanism is a fork mechanism having a rotating arm, the semiconductor wafer is held by the fork, and the fork is moved to a rotation center of the rotating arm, The wafer mounting part provided at the center of rotation is raised to lift the semiconductor wafer, and the fork is rotated so that the notch is at a predetermined position with respect to the fork, and the wafer mounting part is lowered. Holding the semiconductor wafer with the fork, and moving the fork onto the support point to support the semiconductor wafer with the support point. 7. A wafer mounting mechanism for mounting a semiconductor wafer, comprising: a wafer supporting mechanism for supporting the semiconductor wafer at a plurality of supporting points; and a wafer supporting mechanism for holding the semiconductor wafer by a holding section. A transfer mechanism for transferring and a position of a notch provided on the outer periphery of the semiconductor wafer is a predetermined position with respect to a holding portion of the transfer mechanism,
And a rotary positioning mechanism for adjusting the angular position of the semiconductor wafer. 8. The wafer mounting mechanism according to claim 7, wherein the transfer mechanism is a fork mechanism having a rotary arm, and the rotary positioning mechanism is vertically movable provided at a rotation center of the rotary arm. A wafer mounting mechanism comprising a simple wafer mounting part and a rotating mechanism of the rotating arm. 9. The wafer mounting mechanism according to claim 7, wherein the predetermined position of the notch with respect to the holding portion is the notch when the semiconductor wafer is transferred to the wafer supporting mechanism. A wafer mounting mechanism, which is predetermined based on a position. 10. The wafer mounting mechanism according to claim 9, wherein a position of the notch when the semiconductor wafer is supported by the wafer supporting mechanism is a shear stress generated in the wafer at the notch portion. The wafer mounting mechanism is characterized in that the angular position is such that is substantially minimum. 11. The wafer mounting mechanism according to claim 10, wherein the plurality of support points are arranged at equal intervals on a circumference,
A wafer mounting mechanism for mounting the semiconductor wafer on the support point such that a notch of the semiconductor wafer is arranged at a predetermined angle from one of the support points. 12. The wafer mounting mechanism according to claim 11, wherein the predetermined angle is ¼ of an angle formed by two adjacent support points. Placement mechanism. 13. A semiconductor manufacturing apparatus for processing a semiconductor wafer, the wafer supporting mechanism supporting the semiconductor wafer at a plurality of supporting points, and the semiconductor wafer being transferred to the wafer supporting mechanism while being held by a holding section. So that the transfer mechanism and the position of the notch provided on the outer periphery of the semiconductor wafer are at a predetermined position with respect to the holding portion of the transfer mechanism,
A semiconductor manufacturing apparatus, comprising: a rotary positioning mechanism for adjusting an angular position of the semiconductor wafer. 14. The semiconductor manufacturing apparatus according to claim 13, wherein the transfer mechanism is a fork mechanism having a rotation arm, and the rotation positioning mechanism is capable of moving up and down provided at a rotation center of the rotation arm. A semiconductor manufacturing apparatus comprising a wafer mounting part and a rotating mechanism of the rotating arm. 15. The semiconductor manufacturing apparatus according to claim 13, wherein the predetermined position of the notch with respect to the holding portion is the position of the notch when the semiconductor wafer is transferred to the wafer support mechanism. A semiconductor manufacturing apparatus, which is determined in advance based on the above. 16. The semiconductor manufacturing apparatus according to claim 15, wherein at the position of the notch when the semiconductor wafer is supported by the wafer support mechanism, shear stress generated in the wafer at the notch portion is A semiconductor manufacturing apparatus characterized in that the angular position is substantially minimized. 17. The semiconductor manufacturing apparatus according to claim 16, wherein the plurality of support points are arranged at equal intervals on a circumference,
A semiconductor manufacturing apparatus, wherein the semiconductor wafer is placed on the support point such that a notch of the semiconductor wafer is arranged at a predetermined angle from one of the support points. 18. The semiconductor manufacturing apparatus according to claim 17, wherein the predetermined angle is ¼ of an angle formed by two adjacent support points. .