Wafer handling robot

Abstract

This wafer conveyance robot which vacuum-suctions a wafer and conveys the same comprises a hand supporting the wafer. The hand has: a first finger and a second finger; a first suction part provided to the first finger; a second suction part provided to the second finger; and a third suction part provided to a connection part connecting the first finger and the second finger. The first suction part, the second suction part, and the third suction part have a first intake hole, a second intake hole, and a third intake hole, respectively. The wafer is supported such that the center of the wafer is located inside a virtual triangle formed by connecting the first intake hole, the second intake hole, and the third intake hole. The first suction part and the second suction part comprise a closed-figure first projection part and a closed-figure second projection part, respectively. The first projection part and the second projection part each include a circular arc projection part which is formed in a circular arc shape centered about a point located inside the virtual triangle.

Description

Technical Field

[0001] The present invention relates to a wafer transfer robot.

Background Art

[0002] Among wafers to be inspected for semiconductors, there are wafers warped in a concentric circle shape. Also, a wafer transfer robot equipped with a hand having a vacuum suction part may be used for wafer transfer. When transferring a warped wafer, if the suction part is flat, a gap is likely to form between the wafer and the suction part. Then, air continues to flow in from between the wafer and the suction part during vacuum suction, resulting in a suction error. As a method of avoiding such a suction error, there is a robot hand provided with a suction cup at the suction part (see, for example, Patent Document 1).

[0003] According to Patent Document 1, by providing a suction cup at the suction part, the suction cup can be deformed to conform to the wafer, and the suction error can be avoided to some extent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a conventional wafer transfer robot, there has been a problem that it is difficult to perform stable three - point support while reducing suction errors.

[0006] For example, in the configuration of Patent Document 1, the thickness of the entire hand increases due to the addition of suction cups to the suction part, making it impossible to insert the wafer all the way into the cassette and thus preventing stable three-point support. Considering the weight of a warped wafer, if it is supported at two points near the front of the cassette, a bending moment due to cantilever support is applied to the suction part, making it easy for the wafer to detach from the suction part. Also, when support is provided by suction cups, the suction position may fluctuate due to suction force and vibration, leading to wafer positioning errors in subsequent processing. Furthermore, if the shape of the suction part is elliptical, the suction area cannot be maximized due to the geometric relationship described later, leaving the possibility of suction errors.

[0007] This invention was made to solve these problems and aims to provide a wafer transfer robot that can perform stable three-point support while maintaining suction force. [Means for solving the problem]

[0008] An example of a wafer transport robot according to the present invention is: A wafer transport robot that vacuum-suctions and transports wafers, The wafer transport robot is equipped with a hand that supports the wafer, The aforementioned hand, First finger and second finger, The first suction portion provided on the first finger, The second suction portion provided on the second finger, A third suction part is provided at the connecting part that connects the first finger and the second finger, Equipped with, The first adsorption portion, the second adsorption portion, and the third adsorption portion each have a first intake hole, a second intake hole, and a third intake hole, The wafer is supported such that its center is located inside a virtual triangle formed by the first intake hole, the second intake hole, and the third intake hole. The first suction portion and the second suction portion each include a first projection and a second projection, which are both closed in shape. Both the first projection and the second projection include an arc projection that forms an arc centered on a point located inside the virtual triangle. [Effects of the Invention]

[0009] The wafer transfer robot according to the present invention can provide stable three-point support while maintaining suction force. [Brief explanation of the drawing]

[0010] [Figure 1] A perspective view of a configuration including a wafer transport robot according to Embodiment 1 of the present invention. [Figure 2] A diagram showing the relationship between wafer 1 and the second adsorption unit 8. [Figure 3] A diagram illustrating the positional relationship between hand 4 and wafer chuck 16. [Figure 4] A diagram illustrating the relationship between the shape of the adsorption part and the maximum gap between the wafer and the adsorption part. [Figure 5] The overall structure of the hand 4 according to Embodiment 1. [Figure 6] Structure of the suction unit in a wafer transport robot according to Embodiment 2. [Figure 7] Structure of the suction unit in a wafer transport robot according to Embodiment 3. [Figure 8] Structure of the suction unit in a wafer transport robot according to Embodiment 4. [Figure 9] Structure of the hand 4 according to Embodiment 5. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described based on the attached drawings. [Embodiment 1] FIG. 1 is a perspective view of a configuration including a wafer transfer robot according to Embodiment 1 of the present invention. The wafer transfer robot can vacuum-adsorb and transfer a wafer 1 to be transferred. Further, the wafer transfer robot can take in and out the wafer 1 from a cassette 2. The cassette 2 for storing the wafer 1 has a structure in which the wafer 1 is supported by left and right wafer holding portions 3, and the wafer holding portions 3 can have a shelf-like structure in which a plurality of them are connected in the vertical direction.

[0012] The wafer transfer robot includes a hand 4 that supports the wafer 1. The hand 4 is configured to be able to handle the wafer 1. The hand 4 includes a first finger 5 and a second finger 6, a first suction portion 7 provided on the first finger 5, a second suction portion 8 provided on the second finger 6, and a third suction portion 9 provided on a connecting portion that connects the first finger 5 and the second finger 6.

[0013] The first suction portion 7, the second suction portion 8, and the third suction portion 9 each have a first suction hole 7a, a second suction hole 8a, and a third suction hole 9a, respectively. The first suction portion 7 and the second suction portion 8 each include a first protrusion portion 7b and a second protrusion portion 8b having a closed figure shape. Further, as shown in FIG. 1 and the like, the third suction portion 9 may similarly include a third protrusion portion 9b having a closed figure shape.

[0014] The wafer transfer robot may include, as actuators, a vertical actuator 10, a first rotational actuator 11a, a second rotational actuator 11b, and a third rotational actuator 11c. The hand 4 may be positioned by these actuators. The wafer transfer robot may include a control unit 12, and the control unit 12 may control these actuators.

[0015] An operation example when the wafer transfer robot takes out the wafer 1 from the cassette 2 will be described below.

[0016] The wafer transfer robot moves the hand 4 using the first rotary actuator 11a, the second rotary actuator 11b, and the third rotary actuator 11c, thereby inserting the hand 4 horizontally into the gap between the wafer 1 to be transferred and the wafer 1 one layer below it. The hand 4 is then moved to a position where the center of the triangle formed by the first suction part 7, the second suction part 8, and the third suction part 9 on the hand 4 coincides with the center of the wafer 1, and the hand 4 is stopped there.

[0017] Next, the wafer transfer robot moves the hand 4 vertically upward using the vertical actuator 10 until the wafer 1 is completely separated from the wafer holding unit 3. At this point, the wafer 1 is lifted by the protrusions (for example, the first protrusion 7b, the second protrusion 8b, and the third protrusion 9b) provided on the suction unit.

[0018] The wafer transfer robot is equipped with a vacuum pump 13. The wafer transfer robot operates the vacuum pump 13 while the wafer 1 is lifted by the first projection 7b, second projection 8b, and third projection 9b formed on the first suction part 7, second suction part 8, and third suction part 9. In this way, air is exhausted from the first intake hole 7a, second intake hole 8a, and third intake hole 9a through the ventilation passage inside the hand 4 (described later, refer to Figure 5, etc.), thereby removing the air between the wafer 1 and the hand 4 at each suction part, and the wafer 1 is adsorbed and supported by the hand 4.

[0019] The wafer transfer robot, with the wafer 1 held in place by the hand 4, pulls the hand 4 horizontally out of the cassette 2 and transports it to a position for subsequent processing.

[0020] The operation of the wafer transfer robot according to this embodiment will be explained using Figures 2 and 3. As an example, we will explain the case in which a wafer that is curved concentrically and downwards is picked up by the second suction part 8 of the hand 4.

[0021] Figure 2 shows the relationship between wafer 1 and the second adsorption part 8. Figure 2(a) is a plan view of the second adsorption part 8, showing the position of the wafer center 15. Figure 2(b) is a cross-sectional view of Figure 2, taken by a plane passing through the wafer center 15 and the center of the second air intake hole 8a. The wafer 1 is shown curved downwards in a concentric manner.

[0022] The second projection 8b of the second adsorption portion 8 includes a first arc projection 8b1 having a first radius and a second arc projection 8b2 having a second radius larger than the first radius.

[0023] When a warped wafer 1 is supported by the hand 4, a gap 14 is created between the second suction part 8 (especially the second arc-shaped projection 8b2) and the wafer 1. If this gap 14 becomes too large, when air is exhausted from the second intake hole 8a, air is continuously supplied to the inside of the second intake hole 8a from the outside through the gap 14, preventing vacuum suction and resulting in a suction error.

[0024] To prevent this, it is effective to either place the suction part at a position where the relative angle with respect to the surface of the hand 4 is small (for example, near the center of the wafer), or to reduce the width W of the second projection 8b (the radial width of the wafer 1).

[0025] Here, it is preferable to position the hand 4 and each suction part away from the center of the wafer 1, as shown in Figure 3.

[0026] Figure 3 illustrates the positional relationship between the hand 4 and the wafer chuck 16. To avoid interference with the wafer chuck 16, which is the destination for wafer transfer, it is preferable to position the hand 4 (including the first suction part 7, the second suction part 8, and the third suction part 9) outside the area of ​​the wafer chuck 16. In semiconductor inspection, the wafer 1 may be rotated at high speed, and in order to achieve stable rotation, it is preferable to maximize the contact area between the wafer 1 and the wafer chuck 16.

[0027] Therefore, it is preferable to provide the first adsorption part 7, the second adsorption part 8, and the third adsorption part 9 near the outer periphery of the wafer 1 of the hand 4, but the relative angle of the wafer 1's curvature becomes larger near the outer periphery of the wafer 1.

[0028] Furthermore, in the example shown in Figure 2, reducing the area surrounded by the inner circumference 8c of the second projection 8b reduces the suction force, increasing the risk of wafer 1 falling during wafer transport. Therefore, it is preferable to increase the area of ​​the region surrounded by the inner circumference 8c.

[0029] Therefore, by creating a suction structure that maximizes the area of ​​the region surrounded by the inner circumference 8c while minimizing the width W, it is possible to reduce the risk of the wafer falling while avoiding interference with the wafer chuck 16.

[0030] Figure 4 illustrates the relationship between the shape of the adsorption part (especially the protrusion) and the maximum gap between the wafer and the adsorption part. Figure 4(a) shows an example where the shape of the protrusion is a closed shape 17 having two arcs concentric with the outer circumference of the wafer. Figure 4(b) shows an example where the shape of the protrusion is a circle 18. Figures 4(c) and 4(d) show examples where the shape of the protrusion is an ellipse 19. For comparison, the closed shape 17 is superimposed in Figures 4(a) to (c).

[0031] Figures 4(a) to 4(c) show both a plan view illustrating the shape of the protrusion and a cross-sectional view showing the positional relationship between the wafer and the protrusion.

[0032] To simplify the explanation, the following conditions will be assumed. The closed shape 17, the circle 18, and the ellipse 19 all have the same area (adsorption area). • The curvature of wafer 1 is approximated by a straight line near the adsorption region. • In the figure, ΔR1 to ΔR3 represent the distance between (1) and (2) below. (1) Contact point between the wafer and the protrusion (2) The point where the maximum gap between the wafer and the protrusion occurs. ·θ is the angle of the wafer's curvature relative to the horizontal plane.

[0033] The points corresponding to (1) and (2) above are indicated by the "×" symbol in the plan views of Figures 4(a) to 4(c). The cross-sectional views of Figures 4(a) to 4(c) are drawn from planes passing through the points corresponding to (1) and (2) respectively.

[0034] In the example shown in Figure 4(a), the protrusion includes an arc-shaped portion (arc-shaped protrusion). In this example, ΔR1 is the distance (difference in radii) between the two arcs in the closed shape 17. The distances R and R' between each arc and the wafer center 15 are constant and do not depend on the position in the wafer circumferential direction. Therefore, ΔR1 is also constant, and the maximum gap is ΔR1sinθ.

[0035] In Figure 4(b), ΔR2 coincides with the diameter of circle 18. If we assume that the diameter of circle 18 coincides with ΔR1, then the entire region enclosed by the circle is contained within the closed shape 17, and therefore the area of ​​the circle is smaller than the area of ​​the closed shape 17. Consequently, for the areas of the closed shape 17 and circle 18 to be equal according to the premise, it is necessary that at least ΔR2 > ΔR1. Thus, the relationship for the maximum gap is ΔR2sinθ > ΔR1sinθ.

[0036] In Figure 4(c), if we let R be the radius of the arc closer to the wafer center 15 and R+ΔR1 of the two arcs in the closed shape 17, then a portion of the region enclosed by the ellipse 19 deviates outside the region enclosed by radius R+ΔR1. If we let Δr be the shortest distance between the point furthest from the wafer center in this deviated region and the circle with radius R+ΔR1, then we can write ΔR3 = ΔR1 + Δr in Figure 4(c). Therefore, the relationship for the maximum gap is ΔR3sinθ > ΔR1sinθ.

[0037] Based on the analysis in Figures 4(a) to 4(c) above, the gap (or the area of ​​the gap) is minimized in the case of Figure 4(a), that is, when the shape of the protrusion is the closed shape 17.

[0038] In the example shown in Figure 4(a), the closed shape 17 includes a straight section connecting the two arcs. However, this section does not need to be a straight line; for example, the two arcs may be connected by two semicircular shapes, as shown in Figure 2(a) for the second projection 8b. In this case as well, since ΔR1 in Figure 4(a) remains unchanged, there is no difference in the comparison results between Figures 4(a) to 4(c).

[0039] Figure 4(d) illustrates the relationship between the shape of the protrusion and the maximum gap between the wafer and the adsorption part. On the circumference of circle 20 with radius R, the height of the concentrically curved wafer's curvature is constant. Similarly, on the circumference of circle 21 with radius R+ΔR1, the height of the wafer's curvature is also constant. When the shape of the protrusion is the closed shape 17, the back surface of the concentrically curved wafer either overlaps the protrusion without gap along these circumferences, or approaches the protrusion so that the gap between them is small. This reduces air leakage.

[0040] In contrast, if the protrusion is circular 18 or elliptical 19 as a comparative example, in the region outside the constant radius circumference (for example, region 22 if the adsorption part shape is elliptical 19), the height of the wafer's curvature and the height of the protrusion will not match, making it easy for gaps to form and causing leakage. This situation can be avoided by using a shape such as the closed shape 17 in Figure 4 or the second protrusion 8b in Figure 2.

[0041] Figure 5 shows the overall structure of the hand 4 according to this embodiment. This figure is a plan view including the hand 4 and the wafer 1. The hand 4 has a first finger 5 and a second finger 6, a first suction part 7 at or near the end of the first finger 5, a second suction part 8 at or near the end of the second finger 6, and a third suction part 9 at the connecting part (base) that connects the first finger 5 and the second finger 6.

[0042] Wafer 1 is supported such that its center 15 is located inside a virtual triangle 26 (a virtual triangle) formed by connecting the first intake hole 7a, the second intake hole 8a, and the third intake hole 9a. If the first intake hole 7a, the second intake hole 8a, and / or the third intake hole 9a cannot be considered as points, the position of each intake hole may be defined as appropriate, for example, by interpreting it as the centroid of each intake hole in a plan view.

[0043] The first projection 7b, the second projection 8b, and the third projection 9b have a closed shape that includes a protruding portion (arc projection) that forms an arc centered on the wafer center 15. The center of the arc does not need to coincide with the wafer center 15 as long as it is located inside the virtual triangle 26, and the position of the wafer center 15 when actually transporting the wafer 1 may be shifted within a predetermined tolerance range.

[0044] In particular, in the example of Figure 5, the first projection 7b includes an inner arc projection (i.e., a first arc projection along a virtual circle 24 concentric with the outer circumference 23 of the wafer 1 and having a first radius) and an outer arc projection (i.e., a second arc projection along a virtual circle 25 concentric with the outer circumference 23 of the wafer 1 and having a second radius greater than the first radius). Similarly, the second projection 8b also includes a first arc projection along the virtual circle 24 and a second arc projection along the virtual circle 25. Furthermore, the third projection 9b also includes a first arc projection along the virtual circle 24 and a second arc projection along the virtual circle 25.

[0045] The first projection 7b, the second projection 8b, and the third projection 9b protrude toward the foreground of the paper in Figure 5, and the wafer 1 is supported by contact with these projections.

[0046] The first intake port 7a, the second intake port 8a, and the third intake port 9a are connected to a ventilation passage 27 formed inside the hand 4, and the air in each intake port is exhausted by the vacuum pump 13.

[0047] In this way, by aligning the protrusions of each adsorption part with the virtual circles 24 and 25, the width of each protrusion (width in the wafer radial direction) can be reduced while maximizing the area enclosed by the inner circumference of each protrusion. This makes it possible to reduce the gap between the adsorption part and the wafer while maintaining the adsorption force.

[0048] In particular, each projection has a total of two arc-shaped projections on both sides, so that the height of the projections on both sides of each suction part closely matches the height of the wafer's curvature, allowing for good suction of the wafer 1.

[0049] Thus, the wafer transfer robot according to this embodiment can provide stable three-point support while maintaining suction force.

[0050] [Embodiment 2] Figure 6 shows the structure of the suction part in the wafer transfer robot according to Embodiment 2. Figure 6 shows the second suction part 8 and its vicinity on the second finger 6. Hereafter, parts common to Embodiment 1 may be omitted from the explanation.

[0051] The second projection 8b of the second adsorption portion 8 includes a first arc projection 8b1 having a first radius and a second arc projection 8b2 having a second radius larger than the first radius. The width Δr2 (radial width) of the second arc projection 8b2 is larger than the width Δr1 (radial width) of the first arc projection 8b1. That is, the width Δr2 of the second projection 8b on the side further from the wafer center 15 is larger than the width Δr1 on the side closer to the wafer center 15.

[0052] In the example shown in Figure 6, the first and second arc projections 8b1 and 8b2 each have a constant width, but their widths do not have to be constant. If the widths are not constant, the maximum width of the second arc projection 8b2 may be made larger than the maximum width of the first arc projection 8b1.

[0053] The structure of the first projection 7b and the third projection 9b can be the same as that of the second projection 8b.

[0054] By increasing Δr1 and Δr2, it is possible to increase the airflow resistance between the wafer and the protrusion, thereby increasing the adsorption force. On the other hand, increasing Δr1 increases the distance W1 in the radial direction of the wafer at the protrusion, so the maximum gap between the wafer and the protrusion increases.

[0055] Therefore, as shown in Figure 6, by reducing only Δr1, which affects the maximum gap, and increasing Δr2, which does not affect the maximum gap, it is possible to increase the adsorption force while reducing the maximum gap.

[0056] Furthermore, while the wafer and the projection are in contact at the first arc projection 8b1, a gap is created at the second arc projection 8b2, so air inflow during vacuum evacuation occurs at the second arc projection 8b2. From the viewpoint of increasing the ventilation resistance targeting only the incoming air, increasing the width Δr2 of the second arc projection 8b2 is effective.

[0057] [Embodiment 3] Figure 7 shows the structure of the suction part in the wafer transfer robot according to Embodiment 3. Figure 7 shows the second suction part 8 and its vicinity on the second finger 6. Hereafter, parts common to Embodiment 1 or 2 may be omitted from the explanation.

[0058] In Embodiment 3, the second intake port 8a is shaped to extend circumferentially along the shape of the second projection 8b. For example, the second intake port 8a is formed in an arc shape. More precisely, the second intake port 8a includes a portion that forms an arc of a certain width (concentric with the arc relating to the second projection 8b).

[0059] Generally, increasing the size of the intake pores can increase the adsorption force. However, if the intake pores are circular, increasing the diameter increases the distance W2 in the wafer radial direction, and thus the gap area expands.

[0060] In contrast, by making the intake holes circumferentially oriented (arc-shaped) as shown in Figure 7, it is possible to increase the area of ​​the intake holes and thus the adsorption force while reducing the distance W2 in the wafer radial direction.

[0061] The structure of the first intake port 7a and the third intake port 9a can be the same as that of the second intake port 8a.

[0062] [Embodiment 4] Figure 8 shows the structure of the suction part in the wafer transfer robot according to Embodiment 4. Figure 8 shows the second suction part 8 and its vicinity on the second finger 6. Hereafter, parts common to any of Embodiments 1 to 3 may be omitted from the explanation.

[0063] Figure 8(a) shows a plan view, and Figure 8(b) shows a perspective view. The height of the second arc projection 8b2 is greater than the height of the first arc projection 8b1. Here, "height" refers to the height shown in Figure 8( a ) refers to the dimension in the depth direction of the paper surface.

[0064] By creating a height difference in the protrusions in this way, the concentric, downward-curving shape of the wafer conforms to the shape of the protrusions, thereby reducing the gap between the wafer and the protrusions. The height difference can be determined, for example, based on the amount of curvature of the wafer to be transported.

[0065] In the example shown in Figure 8, the heights of the first arc projection 8b1 and the second arc projection 8b2 are constant, but their heights do not have to be constant. If the heights are not constant, the maximum height of the second arc projection 8b2 may be greater than the maximum height of the first arc projection 8b1.

[0066] [Embodiment 5] Figure 9 shows the structure of the hand 4 according to Embodiment 5. Hereafter, parts common to any of Embodiments 1 to 4 may be omitted from the explanation.

[0067] In the example shown in Figure 9, portions of the first finger 5 and the second finger 6 are extended to match the shapes of the first suction portion 7 and the second suction portion 8. In particular, at least a portion of the outer circumference of the first finger 5 and the second finger 6 forms an arc. Specifically, the first finger 5 has a first arc portion 5a in the part that forms the outside of the hand 4, and the second finger 6 has a second arc portion 6a in the part that forms the outside of the hand 4. The centers of the first arc portion 5a and the second arc portion 6a can be the wafer center 15 (or the centers of the arcs of the first projection 7b and the second projection 8b).

[0068] By shaping the fingers in this way, the suction area can be enlarged without changing its radial width, for example, by extending it circumferentially. This allows for an increase in the suction area and improved suction force without increasing the gap between the wafer and the protrusion.

[0069] [Differentiation] It is also possible to combine two or more of the embodiments 1 to 5 described above.

[0070] In embodiments 1 to 5, each projection has a total of two arc-shaped projections on both sides (for example, the first arc-shaped projection 8b1 and the second arc-shaped projection 8b2 in Figure 2), but it is also possible to have only one arc-shaped projection and make the other a shape other than an arc (for example, a straight line or an ellipse).

[0071] Furthermore, the shape of the portion connecting the inner portion (for example, the first arc projection 8b1) and the outer portion (for example, the second arc projection 8b2) of each projection can be changed as appropriate. In the example in Figure 2, the two connecting portions are each semicircular in shape, but as shown in Figure 4, the two connecting portions may each be linear in shape, or they may have any other shape. [Explanation of symbols]

[0072] 1...wafer 2…Cassette 3…Wafer holding section 4…Hand 5…First finger 5a...First arc section 6…Second finger 6a...Second circular arc 7…First suction part 7a...First intake port 7b...first protrusion 8...Second suction part 8a...Second intake port 8b…Second protrusion 8b1...First circular arc projection 8b2...Second arc projection 8c...Inner circumference of the second projection 9…Third suction part 9a...Third intake port 9b...Third protrusion 10…Vertical actuator 11a...First Rotary Actuator 11b...Second Rotary Actuator 11c...Third Rotation Actuator 12…Control Unit 13… Vacuum pump 14…Gap 15… Wafer center 16… Wafer chuck 17…Closed figure shape 18…Circular 19…Ellipse 20... yen 21... yen 22...Area 23…Outer perimeter 24… Virtual Yen 25…Virtual Yen 26…Virtual triangle (a hypothetical triangle) 27... Ventilation channel

Claims

1. A wafer transport robot that vacuum-suctions and transports wafers, The wafer transport robot is equipped with a hand that supports the wafer, The aforementioned hand, First finger and second finger, The first suction portion provided on the first finger, The second suction portion provided on the second finger, A third suction part is provided at the connecting part that connects the first finger and the second finger, Equipped with, The first adsorption portion, the second adsorption portion, and the third adsorption portion each have a first intake hole, a second intake hole, and a third intake hole, The wafer is supported such that its center is located inside a virtual triangle formed by the first intake hole, the second intake hole, and the third intake hole. The first adsorption portion and the second adsorption portion each include a first projection and a second projection, which are closed in shape. Both the first projection and the second projection include an arc projection that forms an arc centered on a point located inside the virtual triangle, The first projection and the second projection each include a first arc projection having a first radius and a second arc projection having a second radius larger than the first radius. The radial width of the second arc projection is greater than the radial width of the first arc projection. Wafer handling robot.

2. The wafer transport robot according to claim 1, wherein the first intake port and the second intake port are formed in an arc shape.

3. The wafer transport robot according to claim 1, wherein the height of the second arc projection is greater than the height of the first arc projection.

4. The wafer transport robot according to claim 1, wherein at least a portion of the outer circumference of the first finger and the second finger forms an arc.

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