JP2001110874A - Transport hand for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the manufacturing yield of a semiconductor wafer in a working process by improving the positioning accuracy of the wafer with respect to a transport hand. SOLUTION: A transport hand 10 is provided with a hand section 11 which is extended along the periphery of a semiconductor wafer W and almost horizontally bears the wafer W. The hand section 11 has a supporting surface 13a inclined in the thickness direction of the born wafer W at a prescribed inclined angle and bears the wafer W in such a way that the peripheral edge of the wafer W is placed on the surface 13a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer transfer hand used in a transfer apparatus for handling a semiconductor wafer in a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Semiconductor manufacturing processes include a plurality of processing steps for a semiconductor wafer, such as etching, oxidation, photoresist coating, and ion implantation. In each processing step, the semiconductor wafer is sequentially transported in the apparatus or between the apparatuses in a vacuum or the atmosphere, and is transferred to the next step. Handling of fragile and easily damaged semiconductor wafers is performed by a transfer device provided with a dedicated transfer hand.

[0003] 1 for handling semiconductor wafers
As one method, a transfer hand according to a type called a wafer guide method is known. FIG. 5 and FIG. 6 show an embodiment of this type of transport hand conventionally used. The conventional transfer hand 50 has an arc-shaped hand portion 51 extending along the periphery of the semiconductor wafer W. A mounting surface 51a on which the semiconductor wafer is mounted extends horizontally along the inside of the hand portion 51. This transfer hand 50
Is attached to the tip of the transfer arm in the transfer device, and is movable in the horizontal direction. The semiconductor wafer W is placed inside the wall 51b of the hand portion 51, and its peripheral portion is
1a, and is made transportable by the movement of the transport arm.

[0004]

The conventional transfer hand has one problem to be solved. That is the problem of positioning the semiconductor wafer with respect to the transport hand. In designing the transfer hand, it must be ensured that the semiconductor wafer is properly mounted on the mounting surface 51a surrounded by the wall 51b. In actual manufacturing, the semiconductor wafer diameter D has some variation Δd. The outer shape of the placing surface 51a, that is, the distance D 'between the opposing walls.
Must be designed in consideration of at least the dimensional error due to this variation. Further, a slight play s (2 s on both sides) when the semiconductor wafer having the largest diameter is placed on the mounting surface 51a must be considered.

For example, in the design of a transfer hand for a 6-inch (approximately 150 mm) semiconductor wafer, the dimensional error is set to +/- 0.5 mm and the play is set to 0.1 mm.
Considering 5 mm, the outer dimensions of the mounting surface are set to about 151 mm. In such a design, when handling a semiconductor wafer having a minimum diameter (149.5 mm), the position of the semiconductor wafer with respect to the transfer hand is about 1.5 mm.
May shift. When the semiconductor wafer is clamped from the transfer hand (using a clamp ring or a clamp claw) and transferred to the next step, the problem of the positional shift may become serious.

Increasing the number of chips cut from one semiconductor wafer is extremely important in a semiconductor manufacturing process. In order to effectively utilize the wider area of the semiconductor wafer, the center of the semiconductor wafer must coincide with the center of the area where each process is performed. However, since the center of the region to be processed usually depends on the position of the clamp on the semiconductor wafer, the shift of the center reduces the yield of chips around the semiconductor wafer.

Further, as shown in FIG. 6, in the conventional transfer hand 50, the bottom surface of the semiconductor wafer W and the mounting surface 51a are in surface contact. Thereby, the mounting surface 51a
The fine dust deposited on the top adheres to the bottom surface of the semiconductor wafer W. It will be apparent to those skilled in the art that dust adhering to the semiconductor wafer W can be a serious problem in the process of manufacturing a semiconductor device.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the positioning accuracy of a semiconductor wafer with respect to a transfer hand, and to solve the above-mentioned problems caused by the displacement.

Another object of the present invention is to minimize the adhesion of dust to the semiconductor wafer during handling by a transfer hand.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a semiconductor wafer transfer hand. The transfer hand according to the present invention includes a hand portion that extends along the periphery of the semiconductor wafer and supports the semiconductor wafer substantially horizontally. The hand portion has a support portion inclined at a predetermined inclination angle in a thickness direction of the semiconductor wafer to be supported, and supports the semiconductor wafer by mounting a peripheral portion of the semiconductor wafer on the support portion.

The support of the semiconductor wafer by the inclined support portion keeps the semiconductor wafer at a fixed position relative to the transfer hand in the horizontal direction regardless of the variation in the diameter of the semiconductor wafer. In particular, when the transfer hand is moved by the transfer device in a state where the semiconductor wafer is supported, the minute vibration accompanying the movement is transmitted to the transfer hand, and the semiconductor wafer supported by the inclined support portion receives the minute vibration. It is positioned at the most stable position, that is, the position where the semiconductor wafer is horizontal.

Here, it is preferable that the support portion is formed along an inner peripheral surface of the hand portion.

It is preferable that the diameter of the lowermost part of the supporting portion is smaller than the minimum diameter of the semiconductor wafer to be supported, and the diameter of the uppermost part is larger than the maximum diameter of the semiconductor wafer to be supported.

Further, 50% of the peripheral portion of the semiconductor wafer
It is preferable that the above region is placed on the support.

Further, a plurality of the support portions may be formed at appropriate positions on the inner peripheral surface of the hand portion.

The inclination of the support is preferably in the range of 45 to 60 degrees with respect to a horizontal plane, and the surface roughness of the support is preferably Rmax 0.8 μm or less.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a transport hand according to one embodiment of the present invention. The transfer hand 10 includes a hand unit 11 and an arm unit 12 that directly support a semiconductor wafer. As is apparent from the drawing, the hand unit 11 is a roughly arc-shaped frame, and the arm unit 12 is a plate-like member extending from the center of the frame. The transfer hand 10 is provided at the tip of an arm of a transfer device described later with the arm 12
Are attached to the transport device by connecting the tips of the transport devices. The transfer hand 10 is made of a material having high rigidity and light weight,
For example, it is obtained by molding aluminum. In the embodiment shown in the drawings, the hand unit 1
A hole 10a is formed at an appropriate position of the arm 1 and the arm 12.

The hand section 11 is an arc-shaped frame having a size substantially conforming to the outer dimensions of the semiconductor wafer W. Hand unit 1 for transferring a semiconductor wafer to / from another transfer device
1 is terminated at a predetermined opening angle θ.
In order to guarantee a stable support of the semiconductor wafer placed on the hand unit 11, the opening angle θ should not be too large. In one embodiment, the opening angle θ is approximately 120
Degrees.

The hand section 11 has the same cross-sectional shape along the continuous direction. FIG. 2 shows a cross section at an arbitrary position of the hand unit 11. As shown in the figure, the hand unit 11 is basically composed of a wall 13 and a flange 14 extending inside the wall 13. Here, the wall 13
Is inclined at a predetermined angle (hereinafter, this surface is referred to as an inclined surface 13a), and the inclined surface 13a is a surface that supports the semiconductor wafer W. The flange portion 14 extends inward from the lower end of the inclined surface 13a.

That is, as shown in FIGS. 2 and 3, the semiconductor wafer W is accommodated inside the wall 13 and its peripheral end is brought into contact with the inclined surface 13a to be supported between the opposed inclined surfaces. . The peripheral end of the semiconductor wafer W makes line contact at a predetermined height position on the inclined surface 13a. According to such a supporting method, although the height position on the inclined surface 13a on which the semiconductor wafer W is supported changes due to the error of the diameter of the semiconductor wafer W, the center position in the horizontal direction is constant. Slope 1
In order to support the semiconductor wafer W at 3a, the dimensions of the inner diameter D1 at the upper end and the inner diameter D2 at the lower end between the opposed inclined surfaces 13a with respect to the diameter D of the semiconductor wafer W are important. Since the diameter of the semiconductor wafer W to be manufactured has a manufacturing error (here, +/- Δd), the inner diameter D1 at the upper end portion is at least larger than the diameter D + Δd of the semiconductor wafer W in consideration of this. Large design, inner diameter D2 at lower end
Is designed to be at least smaller than the diameter D-Δd. In addition, in order to facilitate the reception of the semiconductor wafer W between the wall portions 13, the inner diameter D1 of the upper end portion needs to have a little space. In the embodiment, the diameter of the semiconductor wafer W is 150 +/- 0.5
mm, the height of the inclined surface 13a is about 3.5 mm, and the inclination angle α is 60 degrees, the inner diameter D1 of the upper end portion is 153 mm.
mm, and the inner diameter D2 of the lower end is preferably 148 mm.

In designing the inclined surface, an inclination angle α and a coefficient of friction k with respect to the horizontal plane are further considered.
Generally, in order to stably support the semiconductor wafer W,
It is preferable to increase the inclination angle α of the inclined surface 13a. When the inclination angle α is small, the force at which the peripheral end of the semiconductor wafer W slides down the inclined surface 13a becomes small, and as a result, the semiconductor wafer W can be supported in an inclined state with respect to the hand unit 11. The nature becomes high. On the other hand, if the inclination angle α is too large, the inclination surface 13 with respect to the own weight of the semiconductor wafer W
a, the risk of locking the semiconductor wafer W between the inclined surfaces 13a is increased. Further, in order to secure a required dimensional difference between the inner diameter D1 of the upper end portion and the inner diameter D2 of the lower end portion, the height H of the wall portion 13 required is increased. From such a viewpoint, the inclination angle α of the inclined surface 13a is preferably about 45 to 60 degrees.

Further, the problem related to the inclination angle relates to the friction coefficient k of the inclined surface 13a. In general,
If the friction coefficient k of the inclined surface 13a is small, the semiconductor wafer W is in the most stable state, that is, its peripheral end is in contact with the inclined surface 13a without any gap, and is in a state of being horizontally supported by the hand portion 11, and At the same time, the problem of locking the semiconductor wafer W is reduced. The surface roughness (surface roughness) of the inclined surface 13a considered in relation to the inclination angle α is Rm
It is preferable that ax ≦ 0.8 μm. The surface roughness may be reduced by coating the inclined surface 13a with a fluororesin such as Teflon (trade name). Further, it is necessary that the surface state of the inclined surface 13a does not change drastically during long-term use, and that stable surface accuracy can be maintained. In one embodiment, it is preferable to perform an anodizing treatment (anodized film) on the surface of the finished aluminum material in order to increase the wear resistance of the inclined surface.

FIG. 4 is a plan view schematically showing a transfer operation of the semiconductor wafer W in the transfer device 40 provided with the transfer hand 10. The transfer hand 10 is attached to a tip of an arm 41 of the transfer device 40. The transport device 40
The transfer hand 10 is moved to transfer the semiconductor wafer W to the wafer table 61 in the process chamber 60 in accordance with the movement of the arm 41 which is rotated and driven up and down by the step motor.

The semiconductor wafer W is mounted on the wafer aligner 72 of the buffer stage 71 by a wafer transfer robot (not shown). At this time, the semiconductor wafer W
The wafer aligner 72 is fixed by vacuum suction through three holes 73. The transfer hand 10 is horizontally moved toward the buffer stage 71 and positioned below the semiconductor wafer W placed on the buffer stage 71.
Then, the transfer hand 10 moves upward, the semiconductor wafer W is guided into the wall portion 13 of the hand portion 11, and is supported at the height position of the inclined surface 13a corresponding to the diameter D thereof. At this time, the vacuum suction on the wafer aligner 71 has been released.

Thereafter, the transfer hand 10 moves horizontally toward the transfer device 40 and returns to its original position,
The arm 41 rotates to place the semiconductor wafer W on the wafer table 61 of FIG. Here, the minute vibration of the step motor that drives the arm 41 is transmitted to the transfer hand 10 that is transferring the semiconductor wafer W. Due to the minute vibration, the semiconductor wafer W supported by the hand unit 11 is adjusted to a more stable position on the inclined surface 13a, and the stable support of the semiconductor wafer W is more reliable, that is, the error of the diameter of the semiconductor wafer W is reduced. Regardless, the horizontal position of the semiconductor wafer W with respect to the hand unit 11 is constant. In order to place the semiconductor wafer W on the hand unit 11 on the wafer table 61 in the process chamber 60, the transfer hand 10 moves horizontally, and the semiconductor wafer W is positioned above the wafer table 61. In this positioning, the transfer hand 10 is accurately controlled so that the center of the hand unit 11 of the semiconductor wafer W and the center of the wafer table 61 match. Here, in the wafer table 61, four wafer lift pins 6 for supporting the semiconductor wafer W are provided.
Two are sticking out.

The transfer hand 10 is lowered to transfer the semiconductor wafer W to the wafer lift pins 62, and the semiconductor wafer W is supported by the wafer lift pins 62. After the transfer hand 10 retreats to the transfer device 40, the semiconductor wafer W is placed on the wafer table 61 by the lowering of the wafer lift pins 62 to be accommodated in the wafer table 61. And the semiconductor wafer W
It is fixed to the wafer table 61 by the clamp ring 63. After that, a process is performed on the semiconductor wafer W. The transfer of the semiconductor wafer W from the process chamber 60 is performed by the transfer device 4 having the same configuration as the transfer device 40.
Due to 0 ′, the wafer is placed on the wafer aligner 82 of the buffer stage 81 by an operation reverse to the above-described loading operation. Thereafter, the semiconductor wafer W is transferred to another processing chamber by a wafer transfer robot (not shown).

As described above, the transfer hand 10 according to the present invention supports the semiconductor wafer W at a fixed position (center position) in the horizontal direction with respect to the hand portion 11. Therefore,
By controlling the center of the hand unit 11 of the transfer hand 10 to be the center of the wafer table 61 of the process chamber 60, the center of the semiconductor wafer W and the wafer table 6 are controlled.
The semiconductor wafer W can be accurately placed on the wafer table 61 such that the center of the semiconductor wafer W coincides with the center of the wafer.

The embodiment of the present invention has been described with reference to the drawings. Obviously, the scope of application of the present invention is not limited to the items shown in the above embodiment. In the embodiment, the entire inner peripheral surface of the wall portion 13 of the hand portion 11 is formed as the inclined surface 13a. However, a plurality of convex portions projecting inward are formed at appropriate places on the inner peripheral surface (preferably formed at opposing positions), and the inner peripheral surface is used as an inclined surface to support the semiconductor wafer W therebetween. It can also be configured as follows. In the above-described embodiment, the hand unit 11 is provided with the collar unit 14. However, the collar portion 14 is formed to increase the rigidity of the hand portion 11, and the semiconductor wafer W does not come into contact therewith. Therefore, if the strength of the hand part 11 is sufficient, the collar part 14 is not always necessary.

[0029]

As described above, according to the present invention, the positioning accuracy of the semiconductor wafer with respect to the transfer hand is dramatically improved. As a result, the center of the semiconductor wafer can be matched with the center of the region where the semiconductor wafer is processed, and the manufacturing yield can be improved.

Further, since the transfer hand according to the present invention supports the semiconductor wafer by line contact at the peripheral end thereof, the adhesion of dust to the semiconductor wafer during handling can be minimized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a transport hand according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 showing a cross section of the hand unit.

FIG. 3 is a perspective view of a transfer hand in a state where a semiconductor wafer is supported.

FIG. 4 is a plan view showing a transfer operation of the semiconductor wafer in the transfer device provided with the transfer hand according to the present invention.

FIG. 5 is a perspective view of a conventional transfer hand.

6 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 W semiconductor wafer 10 transfer hand 10a hole 11 hand part 12 arm part 13 wall part 13a inclined surface 14 collar part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Okada 2350 Kihara, Miura-mura, Inashiki-gun, Ibaraki Japan F-term in Texas Instruments Co., Ltd. 3C007 DS01 ES02 EV07 EW00 NS09 NS11 NS17 3F061 AA01 BA02 BE12 BF00 DB00 DB04 DB06 5F031 CA02 FA01 FA07 FA11 GA05 GA47 MA26 MA31 MA32 PA26

Claims (8)

[Claims] 1. A semiconductor device, comprising: a hand portion extending along a periphery of a semiconductor wafer and supporting the semiconductor wafer substantially horizontally, wherein the hand portion supports at a predetermined inclination angle in a thickness direction of the semiconductor wafer to be supported. And a semiconductor wafer transfer hand for supporting the semiconductor wafer by placing a peripheral portion of the semiconductor wafer on the support portion. 2. The semiconductor wafer transfer hand according to claim 1, wherein said support portion is formed along an inner peripheral surface of said hand portion. 3. The semiconductor wafer according to claim 2, wherein the lowermost diameter of the support portion is smaller than the minimum diameter of the semiconductor wafer to be supported, and the uppermost diameter is larger than the maximum diameter of the supported semiconductor wafer. Transfer hand. 4. The semiconductor wafer transfer hand according to claim 3, wherein a region of 50% or more of a peripheral portion of said semiconductor wafer is placed on said support portion. 5. The semiconductor wafer transfer hand according to claim 1, wherein a plurality of the support portions are formed at appropriate positions on an inner peripheral surface of the hand portion. 6. An inclination angle of the support portion is 4 with respect to a horizontal plane.
The transfer hand for a semiconductor wafer according to claim 1, 2, 3, 4, or 5, wherein the angle is in a range of 5 to 60 degrees. 7. The surface roughness of the supporting portion is Rmax 0.8.
7. The transfer hand for a semiconductor wafer according to claim 6, wherein the diameter is not more than μm. 8. A transfer device for a semiconductor wafer, comprising the transfer hand according to claim 1 at a tip of a movable arm.