TW202324583A - Robot hand capable of depositing and removing wafers without causing breaking - Google Patents

Abstract

An objective is that even if a distance between shelves of cassettes is relatively small, a robot hand can suck and hold wafers for depositing and removing without causing breaking . The solution is a robot arm 6, which is a plate-like robot hand 6 attached to a robot 1 and having a suction face 60 having a suction port 62. The suction port 62 sucks and hold a convex spherical surface of a wafer 90 that is curved into a dome shape. The robot hand 6 has: an installment port 61 arranged at a rear end and mounted to the robot 1, and a first suction portion 64 and a second suction portion 65 which form a front end side of the robot hand 6 and are formed to be bifurcated, and are provided with the suction port 62 for sucking the wafer 90. The first suction part 64 and the second suction part 65 are alternately formed with a plurality of slits 640 (slits 650) so as to be bendable, like fingers, along the convex spherical surface of the wafer 90.

Description

manipulator

The invention relates to a plate-shaped manipulator for holding wafers.

When the warped dome-shaped wafer is sucked and held by a robot to be carried out from the cassette, a robot equipped with a suction cup as disclosed in Patent Document 1 is used. In order to carry out the wafers stored in the cassette with such a manipulator with a thicker overall thickness including the suction cup, the distance between the shelf on which the wafer is placed in the cassette and the shelf is set to be large. Therefore, the number of wafers that can be accommodated in the cassette decreases, and the frequency of changing the cassette increases.

In order to solve this problem, in order to be able to carry out the wafers stored in the cassettes with a small distance between the shelf and the shelf, as disclosed in Patent Document 2, for example, a device that sucks and holds the outer peripheral portion of the wafer is used. The manipulator of the suction cup. prior art literature patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2020-202324 Patent Document 2: Japanese Patent Laid-Open No. 2017-045784

The problem to be solved by the invention However, in the manipulator disclosed in Patent Document 2, when the wafer is thin, there is a problem of cracking the held wafer. Therefore, what is required is a manipulator that can take out and put wafers in without causing breakage even if the distance between the shelves of the cassette is small.

means to solve problems The present invention to solve the above-mentioned problems is a manipulator, which is a plate-shaped manipulator, installed on a robot, and has a suction port on the suction surface, and the suction port sucks and holds the convex spherical surface of the wafer that has been bent into a dome shape. , the above-mentioned manipulator has: a mounting part, arranged at the rear end, and installed on the robot; The suction port of the wafer, the first suction part and the second suction part are alternately formed with a plurality of slits so as to bend like fingers along the convex spherical surface of the wafer.

Invention effect Since the manipulator of the present invention is a thin plate-shaped manipulator that does not have a suction cup, etc., it can enter above the wafers placed on the shelf of the cassette with a relatively small distance between the shelf and the shelf, and For example, by lowering the manipulator that has entered the cassette, the width of the plurality of slits formed alternately by the manipulator can be expanded, and the suction surface can be conformed along the dome-shaped convex spherical surface of the wafer. contact with the wafer. And, for example, when the wafer recognition sensor disposed on the manipulator reacts and the wafer recognition sensor is turned on (ON), the suction port of the manipulator is connected to the suction source, so that there is no vacuum leak. Appropriate suction and retention of dome-shaped wafers in the presence of air. Also, the thinned wafer is no longer bent after, for example, grinding a dome-shaped wafer. The manipulator can also attract and hold the unbent and thinned wafers, and can move the processed wafers into the cassettes for unbent wafers without causing breakage.

form for carrying out the invention The robot 1 shown in FIG. 1 is used to carry out, for example, the dome-shaped wafer 90 accommodated in the cassette 4 from the cassette 4, or to place it on a not-shown work clamp or center it. The workbench, or the robot that carries the film cassette 4, is equipped with the manipulator 6 of the present invention, such as a robot that is arranged on a grinding device, a grinding device or a tool cutting device not shown in the figure.

The cassette 4 shown in FIG. 1 has, for example, a bottom plate 40, a top plate 41, a rear wall 42, two left and right side walls 43, and an opening 44 on the front side (+Y direction side), and the wafer 90 can be carried out from the opening 44. Imported composition. Inside the cassette 4 , a plurality of shelf parts 45 are formed at predetermined intervals in the vertical direction, and the wafers 90 can be accommodated one by one in the shelf parts 45 . In addition, the configuration of the cassette 4 is not limited to this example.

The circular wafer 90 shown in FIG. 1 and FIG. 2 is, for example, a silicon wafer, and is curved into a dome shape because it is gradually warped from the center of the wafer 90 toward the outer periphery 903 . That is, the dome-shaped curvature refers to, for example, a curvature such that when the wafer 90 is placed on the shelf portion 45 of the cassette 4 with the front surface 900 facing downward, the front surface 900 of the wafer 90 is lifted from the The area on the central side gradually becomes lower toward the area on the outer peripheral side. In addition, the outer peripheral edge 903 of the wafer 90 is in contact with the shelf portion 45 of the cassette 4 , and the wafer 90 is placed on the shelf portion 45 with the convex spherical surface, that is, the rear surface 906 facing upward. As an example of a dome-shaped wafer 90, the front surface 900 on which unillustrated devices and the like are formed is sealed with a resin, and the dome-shaped curvature is due to, for example, the contraction force of the resin that hardens when the resin is sealed. etc. as the main reason.

A robot 1 shown in FIG. 1 is an articulated robot, and includes a driving unit 3 for moving a manipulator 6 to a predetermined position. The driving part 3 is equipped with, for example: a strip-shaped first arm 31; a strip-shaped second arm 32; a manipulator connecting column 30 extending in the Z-axis direction; a manipulator horizontal movement mechanism 34 that makes the manipulator 6 to move in the horizontal direction; and a lifting mechanism 35 for simplified display.

The upper surface of one end of the first arm 31 is connected to the lower end of the manipulator connecting column 30 . The upper surface of one end of the second arm 32 is connected to the lower surface of the other end of the first arm 31 via a not-shown winding shaft or the like. The lower surface side of the other end side of the second arm 32 is connected to the lift mechanism 35 through the arm drive motor 340 .

The lifting mechanism 35 is, for example, an electric cylinder or the like, and moves the manipulator 6 up and down in the Z-axis direction. The manipulator horizontal movement mechanism 34 is a pulley mechanism composed of an unshown endless belt, an unshown pulley, an arm drive motor 340 and the like arranged in the first arm 31 and the second arm 32 . In addition, the robot 1 as a whole can rotate in a horizontal plane (X-axis Y-axis plane) with the Z-axis as an axis by the rotational force generated by a motor not shown. Furthermore, the rotational force generated by the arm drive motor 340 can move the first arm 31 and the second arm 32 in a horizontal plane to cross each other or arrange them in a straight line, and at the same time make the manipulator 6 linearly move in the horizontal plane.

On the upper end side of the manipulator connecting column 30, a housing 37 is fixed, and the housing 37 rotatably supports a main shaft 36 having an X-axis direction perpendicular to the vertical direction (Z-axis direction) in FIG. 1 . axis. For example, a motor (not shown) that rotatably drives the main shaft 36 is accommodated inside the casing 37 .

The front end side of the main shaft 36 protrudes from the housing 37 in the −X direction, and a holder 38 on which the rear end side of the manipulator 6 is mounted is disposed on the front end side. As the main shaft 36 is rotated by a motor not shown, the manipulator 6 connected to the main shaft 36 through the supporter 38 will rotate, and the suction surface 60 of the manipulator 6 and the opposite side of the suction surface 60 of the manipulator 6 will be turned upside down. .

The plate-shaped manipulator 6 of the present invention shown in Fig. 1 and Fig. 3 is equipped with: the mounting part 61 is disposed at the rear end of the supporter 38 side, and is installed on the robot 1; and the first suction part 64 and the second The suction unit 65 is formed on the front end side of the robot arm 6 , is formed to fork in a planar view, and is provided with a suction port 62 for sucking the wafer 90 . And, the fronts of the first suction part 64 and the second suction part 65 become the suction surface 60 having the suction port 62, and the above-mentioned suction port 62 sucks and holds the convex spherical surface of the wafer 90 (refer to FIG. 2 ) that has been bent into a dome shape. 906 on the back. In the state where the first suction part 64 and the second suction part 65 are not buckled by external force, each suction surface 60 becomes a flat surface.

The manipulator 6 made of a resin plate as a whole allows the dome-shaped top portion of the wafer 90 to be sucked and held, that is, the central region, to enter the U-shaped opening 600 between the first suction part 64 and the second suction part 65 . The mounting portion 61 serving as the rear end of the manipulator 6 shown in FIG. 3 is, for example, formed in a rectangular shape in plan view. A rigid portion 66 having a substantially rectangular shape in plan view wider than the mounting portion 61 integrally extends from the mounting portion 61 toward the front end side of the manipulator 6 . The attachment portion 61 is formed with a screw through hole (not shown) penetrating in the thickness direction, and is fixed to the holder 38 by bolts.

In the rigid part 66 shown in FIG. 3 , the installation recess 660 for installing the sensor cover 673 is cut to match the shape of the sensor cover 673 and extends to the vicinity of the installation part 61 to form. The housing 673 is a part of the wafer detection sensor 67 for the robot 6 to detect the wafer 90 .

The wafer detection sensor 67 is provided with, for example: a light projecting part 671, which emits detection light; a light receiving part 672, which receives the reflected light reflected from the wafer 90 by the detection light emitted from the light projecting part 671; and a sensor The case 673 accommodates the light projecting unit 671 , the light receiving unit 672 , the wiring 674 connected to the light projecting unit 671 or the light receiving unit 672 , and the like. The light projecting part 671 and the light receiving part 672 are arranged laterally and positioned at the central area of the front end of the rigid part 66 near the U-shaped opening 600 . In addition, the wafer detection sensor 67 is not limited to the above-mentioned retro-reflective photoelectric sensor, and may also be, for example, a pressure sensor, a capacitive sensor, and the like.

The first suction part 64 and the second suction part 65 formed integrally with the rigid part 66 so as to diverge in a planar view are line-symmetrical about the center line 602 of the manipulator 6 as an axis, for example. The first suction part 64 (the second suction part 65 ) is alternately formed with a plurality of slits 640 (slits 650 ) so as to be bendable like a finger along the back surface 906 which is the convex spherical surface of the wafer 90 that it contacts. That is, the first suction part 64 (second suction part 65 ) formed in an overall elongated shape is cut alternately and parallel to each other from the side (inside) and outside of the U-shaped opening 600 in a direction perpendicular to the direction in which it extends. A linear slit 640 (slit 650 ) having a predetermined length is provided, whereby the first suction portion 64 (second suction portion 65 ) has flexibility that can be flexed mainly in the thickness direction. In addition, the plurality of linear slits 640 (slits 650 ) are not limited to being cut in parallel to each other, and the direction of the notch can also be changed according to the curvature of the dome-shaped convex spherical surface of the wafer 90 . set at an angle.

As shown in FIG. 3 , for example, a substantially circular suction port 62 is one on the front end side and the root side of the first suction part 64 and the second suction part 65, and in the whole manipulator 6, for example, a total of four openings are opened for suction. Face 60. In addition, the number and arrangement|positioning places of the suction opening 62 are not limited to the example shown in FIG. 3. FIG. Each of the suction ports 62 communicates with an internal suction path 623 . The internal suction path 623 is formed in a zigzag shape inside the first suction part 64 (second suction part 65), and passes through the inside of the rigid part 66 and the mounting part 61, and its other end is opened to the mounting part as a suction transmission port. 61 front. In addition, a suction source 69 such as a vacuum generating device is communicated with the suction force transmission port through an external pipe 692 that is flexible so as not to hinder the joint and the swirling operation of the manipulator 6 . For example, a solenoid valve (not shown) is disposed in the external piping 692, and the solenoid valve can be switched between a state in which the suction port 62 is connected to the suction source 69 and a state in which it is not connected.

For example, the suction surface 60 of the first suction part 64 and the second suction part 65 , the front surface of the rigid part 66 , and the exposed surface of the wafer detection sensor 67 embedded in the mounting recess 660 are flush flat surfaces. In addition, the end portions (ridge lines) of the first suction portion 64 and the second suction portion 65 may be chamfered so as not to damage the wafer 90 when they come into contact with the wafer 90 .

Next, the operation of the robot 6 and the operation of the robot 1 in the case where the wafer 90 is sucked and held by the robot 6 shown in FIGS. 1 and 3 and the wafer 90 is transported by the robot 1 will be described.

First, a motor (not shown) rotates the main shaft 36 shown in FIG. 1 to set the manipulator 6 so that the suction surfaces 60 of the first suction part 64 and the second suction part 65 face downward. Next, the manipulator horizontal movement mechanism 34 of the drive unit 3 moves the manipulator 6 horizontally, and the manipulator 6 enters a predetermined position inside the cassette 4 from the opening 44 . That is, the manipulator 6 is positioned above the wafer 90 shown in FIG. Within 600. Also, the center of the backside 906 of the wafer 90 is positioned on the centerline 602 of the manipulator 6 shown in FIG. 1 .

Then, the manipulator 6 shown in FIG. 5 and FIG. 6 descends, and the dome-shaped top part of the center of the wafer 90 enters in the U-shaped opening 600 shown in FIG. 6, and the first suction part 64 and the second suction Portion 65 is in contact with backside 906 of wafer 90 . In addition, as the manipulator 6 descends, the widths of the plurality of slits 640 (slits 650) of the first suction part 64 (second suction part 65) gradually widen, for example, as shown in FIGS. 5 and 6 , The first suction part 64 (second suction part 65) gradually bends along the dome-shaped convex spherical surface of the wafer 90, that is, the back surface 906, like a finger, so that the contact area between the back surface 906 and the suction surface 60 facing downward is gradually maximized. , and by the first suction part 64 (the second suction part 65), the main middle area of the dome-shaped back surface 906 of the wafer 90 is gradually pressed from the radially outer side of the wafer 90 toward the center side.

In addition, the first suction part 64 (second suction part 65) is gradually bent as shown in FIGS. The suction portion 64 (second suction portion 65 ) is so bent that the wafer 90 cannot be properly suctioned and held.

Also, as shown in FIGS. 5 and 6, when the manipulator 6 begins to descend toward the wafer 90, the light projection part 671 of the wafer detection sensor 67 shown in FIGS. 5 and 6 will direct the detection light toward below, and starts shooting per unit of time. And, in parallel with the first suction part 64 (second suction part 65 ) coming into contact with the wafer 90 and starting to buckle, the light emitting device arranged in which the outer peripheral region of the back surface 906 of the wafer 90 is positioned in the region on the front end side of the rigid part 66 Below the part 671 , and the detection light emitted by the light projecting part 671 will be reflected by the back surface 906 . And, when the light receiving time (the time from emitting the detection light from the light projecting part 671 to receiving the reflected light) received by the light receiving part 672 from the reflected light gradually approaching the back surface 906 of the light receiving part 672 in the height direction becomes predetermined. After the set predetermined time or less, it can be recognized that the contact area between the back surface 906 and the suction surface 60 of the first suction part 64 and the second suction part 65 has been maximized. Alternatively, when the amount of light received by the light receiving portion 672 from the reflected light from the back surface 906 approaching gradually in the height direction becomes more than a preset light amount, the back surface 906 and the first suction portion 64 and the second suction portion can be recognized. The contact area of the adsorption surface 60 of 65 has been maximized. In addition, the recognition that the contact area between the back surface 906 of the wafer 90 and the suction surface 60 of the bent first suction part 64 and the second suction part 65 has been maximized can be obtained by, for example, raising and lowering the manipulator 6 shown in FIG. The motor control of the elevating mechanism 35, such as the electric cylinder, etc., is identified from the height position of the manipulator 6.

Once the above-mentioned identification is performed, the electromagnetic valve not shown in the external piping 692 shown in Figs. It is transmitted from each suction port 62 to the suction surface 60 through the external piping 692 and the internal suction passage 623 . Thereby, become following state: Under the state that the contact area of the suction surface 60 of the bent first suction part 64 and the second suction part 65 and the back surface 906 of the wafer 90 has been maximized, the manipulator 6 will be in the absence of vacuum. The wafer 90 is sucked and held in the event of an air leak.

Then, the manipulator 6 is raised with the elevating mechanism 35 shown in FIG. The manipulator 6 holding the wafer 90 is moved in the +Y direction by the manipulator horizontal movement mechanism 34 , and the wafer 90 is carried out from the cassette 4 by the manipulator 6 .

Afterwards, for example, the wafer 90 is transported by the robot 1, and the back surface 906 on which no devices are formed is exposed to the upper side, and is sucked and held by a chuck of a grinding device not shown in the figure, and the rotary grinding is carried out. The wheel descends from above the wafer 90 and grinds the wafer 90 to a predetermined thickness while bringing the grinding stone into contact with the upper surface 906 of the wafer 90 .

Hereinafter, the case where the wafer 90 shown in FIG. 7 that has been ground and thinned is sucked and held by the robot arm 6 will be described. The thinned wafer 90 is flat because it has been ground to remove the domed bow. First, the manipulator 6 is set so that the suction surfaces 60 of the first suction part 64 and the second suction part 65 face downward, and the manipulator 6 is positioned so that the center of the back surface 906 of the wafer 90 is positioned at the center of the manipulator 6. Inside the U-shaped opening 600 (refer to FIG. 3 ). Also, the center of the back surface 906 of the wafer 90 is positioned on the center line 602 of the robot 6 , and the outer peripheral area of the back surface 906 of the wafer 90 overlaps the lower surface of the rigid portion 66 by a predetermined area.

Then, the manipulator 6 shown in FIG. 7 descends and contacts the back surface 906 of the wafer 90 . Since the ground wafer 90 held on, for example, a table not shown is a flat wafer, the first suction part 64 (second suction part 65) does not bend, and the flat suction surface 60 directly contacts the wafer. The flat back 906 of the circle 90 . Moreover, the wafer detection sensor 67 detects that the flat suction surface 60 has been in contact with the flat back surface 906 of the wafer 90 , and the suction force generated by the suction source 69 is transmitted from each suction port 62 to the suction surface 60 . Thereby, the robot 6 becomes a state where the wafer 90 is sucked and held by the respective suction surfaces 60 of the first suction unit 64 and the second suction unit 65 .

The manipulator 6 is raised by the elevating mechanism 35 shown in FIG. 1, and the wafer 90 sucked and held by the manipulator 6 is carried out from a table not shown. Here, although the gravity G1 applied to the wafer 90 shown in FIG. The area on the outer peripheral side of the back surface 906 is in contact with the lower surface of the rigid part 66 by a predetermined area, and therefore the wafer 90 applies a force G2 that presses the contact part upward toward the contact part of the rigid part 66 , so the first suction part 64 The sagging caused by the deflection of (the second suction part 65) does not become excessive but falls within an appropriate range, and the appropriate suction of the thin and flat wafer 90 by the robot arm 6 can be continued. Keep. In addition, in the case where the bent wafer 90 shown in FIG. 5 is suctioned and held by the robot arm 6, it is caused by the deflection of the first suction part 64 (second suction part 65) for the same reason as above. Sagginess does not become excessive.

As mentioned above, since the manipulator 6 of the present invention is a plate-shaped manipulator that does not have a thickness such as a suction cup, it can enter the shelf part 45 of the cassette 4 whose distance between the shelf part 45 and the shelf part 45 is small. Wafer 90 placed above, and by lowering the manipulator 6 that has entered the cassette 4, the widths of the plurality of slits 640 (slits 650 ) alternately formed by the manipulator 6 can be changed, And make the suction surface 60 contact in a manner conforming to the dome-shaped convex spherical surface of the wafer 90 , that is, the back surface 906 . And, for example, when the wafer detection sensor 67 configured on the manipulator 6 reacts, the wafer detection sensor 67 detects the wafer 90, and recognizes the back surface 906 of the wafer 90 and the first suction After the contact area of the suction surface 60 of the second suction part 64 and the second suction part 65 has been maximized, the suction port 62 of the manipulator 6 is connected to the suction source 69, so that it can be properly sucked and kept warped without vacuum leakage. Wafer 90 curved into a dome shape. Also, the thinned wafer 90 is no longer bent after, for example, grinding the dome-shaped wafer 90 . The manipulator 6 can also attract and hold the wafer 90 that is no longer bent and has become thinner, and can carry the processed wafer 90 into the cassette 4 that accommodates the unbent wafer 90 without causing breakage. In addition, a load sensor may be arranged on the supporter 38 of the robot 1 for mounting the robot 6 to detect the force pressing the robot 6 against the wafer 90 . That is, it can also be recognized from the value of the load sensor that the suction surface 60 has conformed to the dome-shaped convex spherical surface of the wafer 90 , that is, the back surface 906 , so that the suction port 62 is connected to the suction source 69 .

The manipulator 6 of the present invention is not limited to the above-mentioned embodiment, and it is of course possible to implement it in various forms within the scope of its technical idea. In addition, the shape of each structure of the robot 1 or the cassette 4 shown in the attached drawings, and each step of sucking and holding the wafer 90 by the robot 6 and carrying it out are not limited thereto, and may be Appropriate changes are made within the range in which the effects of the manipulator 6 of the present invention can be exhibited. For example, the suction openings 62 may be formed on the upper and lower surfaces of the first suction part 64 and the second suction part 65 of the manipulator 6, respectively, so that the upper surface and the lower surface each serve as a suction surface. Also, in the present embodiment, although the manipulator 6 is to carry out the suction and holding of the wafer 90 while descending, it is also possible to turn the wafer 90 shown in FIG. Facing downward, below the wafer 90 placed on the shelf portion 45 of the cassette 4, the manipulator 6 is raised towards the convex spherical surface of the wafer 90 and the back surface 906 which becomes the lower surface, so as to make the contact with the wafer The first suction part 64 and the second suction part 65 of the wafer 90 bend like fingers along the convex spherical surface of the wafer 90 to suction and hold the wafer 90 .

1: Robot 3: drive unit 4: Cassette 6: Manipulator 30: Manipulator connecting column 31: 1st arm 32: 2nd arm 34: Manipulator horizontal movement mechanism 35: Lifting mechanism 36:Spindle 37: Shell 38: Supporter 40: Bottom plate 41: top plate 42: rear wall 43: side wall 44: opening 45:shelves 60: adsorption surface 61: Installation department 62: suction port 64: Part 1 Attraction 65: Part 2 Attraction 66: Rigid part 67: Wafer detection sensor 69: Source of Attraction 90: Wafer 340: Arm drive motor 600:U opening 602: Centerline 623: Internal attraction road 640,650: Slits 660: Recess for installation 671: Projector 672: Light receiving part 673: Sensor housing 674: Wiring 692: External piping 900: front 903: outer periphery 906: back G1: Gravity G2: force X, Y, Z: axes +X,-X,+Y,-Y,+Z,-Z: direction

FIG. 1 is a perspective view showing an example of a cassette for accommodating wafers and a robot including a robot arm of the present invention. FIG. 2 is a cross-sectional view illustrating a dome-shaped curved wafer accommodated in a cassette. Fig. 3 is a perspective view showing an example of the manipulator with the suction surface directed upward. 4 is a side view showing a state in which the manipulator is lowered to touch the convex spherical surface of the dome-shaped wafer, that is, the upper surface (back surface). FIG. 5 is a side view showing a state in which a manipulator touches the convex spherical surface of a wafer bent into a dome shape, that is, the upper surface while bending along the convex spherical surface of the wafer like a finger and conforming. 6 is a plan view showing a state where a manipulator touches the convex spherical surface of a wafer bent into a dome shape, that is, the upper surface while flexing and conforming along the convex spherical surface of the wafer like a finger. 7 is a side view illustrating a state in which a robot arm sucks and holds a ground flat wafer.

1: Robot

3: drive unit

4: Cassette

6: Manipulator

30: Manipulator connecting column

31: 1st arm

32: 2nd arm

34: Manipulator horizontal movement mechanism

35: Lifting mechanism

36:Spindle

37: Shell

38: Supporter

40: Bottom plate

41: top plate

42: rear wall

43: side wall

44: opening

45:shelves

60: adsorption surface

61: Installation department

62: suction port

64: Part 1 Attraction

65: Part 2 Attraction

66: Rigid part

67: Wafer detection sensor

69: Source of Attraction

90: Wafer

340: Arm drive motor

600:U opening

602: Centerline

623: Internal attraction road

640,650: Slits

671: Projector

672: Light receiving part

692: External piping

900: front

903: outer periphery

906: back

+X,-X,+Y,-Y,+Z,-Z: direction

Claims (1)

A manipulator is a plate-shaped manipulator installed on a robot, and has a suction port on the adsorption surface. The suction port attracts and holds the convex spherical surface of the wafer that has been bent into a dome shape. The manipulator has: the installation part is arranged at the rear end and is installed on the robot; and The first suction part and the second suction part become the front end side of the manipulator, and are formed to be bifurcated, and the suction port for sucking the wafer is arranged, A plurality of slits are alternately formed in the first suction part and the second suction part so as to bend like fingers along the convex spherical surface of the wafer.

Images