JPS62124866A - Polishing device - Google Patents

Abstract

PURPOSE:To polish large-diameter wafers with high efficiency by providing a conveyor belt moving from the first polishing mechanism side to the third polishing mechanism side and a feeding device feeding wafers to the belt one by one in a silicone wafer polishing device. CONSTITUTION:The first polishing mechanism 7 has a polishing surface plate 3 and a nozzle 5 feeding an abrasive, and the material of the polishing cloth stuck to the surface plate 3 is different for the second and third polishing mechanisms 8, 9. In addition, a conveying/cleaning device 27, a feeding device 17 and a storage device 18 on both sides and robots 11a, b, c are provided. In this constitution, clean water is allowed to flow from the third polishing mechanism 9 to the first polishing mechanism 7, and wafers 1 are fed onto a conveyor belt 10 from the feeding device 17 one by one. The wafer 1 is pressed on the polishing surface plate 3 and the abrasive 4 is fed for polishing. This device can obtain large-diameter, high-quality wafers for VLSI with a high yield.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a polishing apparatus for wafers, such as silicon wafers, and in particular, it polishes wafers in a single-wafer type and automatically, thereby producing scratch-free, haze-free, and high-quality wafers. The present invention relates to a polishing device suitable for easily obtaining Uni-Naw at a high yield.

[Background of the invention]

The polishing process for wafers, for example, silicon wafers for VLSI, involves a primary polishing process in which high-efficiency polishing is performed to remove the process-altered layer (approximately 10 to 30 μm layer) generated in the previous process (this is generally an etching process). A polysink, a secondary polysink that polishes the surface of the wafer after the first polysink to a scratch-free surface roughness, and a second polysink that finishes the surface of the wafer after this secondary polishing with a haze-free (i.e.
It consists of a tertiary polysink that is polished to a non-cloudy surface.

Conventionally, polishing devices (details will be described later) used to perform the first to third polysinking have been independent. The operator then manually attaches and detaches the polisher to and from each polishing device, and cleans the surface of the polisher between each polish sink. Therefore, there are problems such as not only poor polishing efficiency but also damage to the wafer and contamination. Moreover,
It has become difficult to handle wafers with a size of 6"φ or more by one hand.

These problems will be explained below with reference to the drawings.

FIG. 4 is a schematic side view showing an example of a conventional wafer polishing apparatus (for primary polishing).

This polishing apparatus fixes one or several wafers 1 to each pressure plate 28 by adhesion or vacuum suction, and polishes the wafer 1 while pressing these pressure plates 28 onto a polishing surface plate 3. It is used for (
Precision processing technology for crystalline materials for electronics, p242
．． Science Forum Publishing, January 30, 1985).

To explain this polishing method in detail, the polishing surface plate 3 is rotated around its rotational drive shaft 3a, the pressure plate 28 is rotated and driven around its rotational drive shaft 28a, and the polishing method is rotated. By supplying the abrasive 4 from the nozzle 5 while pressing against the sink cloth 3b, the primary polysink of sea urchin/Sl is performed and the process-affected layer is removed.

After this primary polysink, one worker removes UNINO-1 from the pressure plate 28 or removes it from the pressure plate 28.
The wafer 1 is cleaned as it is and mounted on a polishing device for secondary polishing. The configuration of this polishing apparatus is almost the same as the polishing apparatus for the primary polysink, and the only difference is the polysink cloth, polishing agent, etc. Then, secondary polishing is performed using this polishing device to finish the unino surface to a scratch-free surface roughness.

After this secondary polysink, one operator cleans the wafer 1 in the same manner as before, and mounts it on a polishing device for tertiary polishing. The configuration of this polishing apparatus is almost the same as the polishing apparatus for the primary and secondary polishing machines described above, with the only difference being the polishing cloth, polishing agent, etc. Then, using this polishing device, the surface is polished to a haze-free surface using tertiary polygon polishing. After polishing, the wafer 1 is cleaned.

Therefore, according to the conventional polishing method using Unino's polishing equipment, the operator can
The pressure plate 28 to which the wafers 1 are bonded is transported between each polysink, cleaned, and mounted, which not only reduces the efficiency of the polishing work, but also causes damage to the wafers 1 due to work errors, resulting in poor yields. There were problems such as contamination of the surface of the wafer 1. Moreover, in recent years, the diameter of wafers has increased from 5" to 6" to 8".

It is also becoming difficult for workers to handle the wafer itself.

For the reasons mentioned above, single-wafer polishing equipment that polishes and processes wafers one by one and automates the polishing is being developed, but many of these machines are unable to perform only the primary polishing. It is a polishing device that can perform the above-mentioned ultra-L
This method cannot be applied to the polishing process of flexible silicon wafers for SI.

A polishing apparatus shown in FIG. 5 has been developed as a polishing apparatus capable of performing primary polishing and secondary polishing.

FIG. 5 is a schematic plan view showing another example of a conventional polishing apparatus (capable of performing primary polishing and secondary polishing).

In this polishing apparatus, a polishing surface plate 30 is separated into an outer peripheral part 20 and an inner peripheral part 21, and a vacuum chuck 29 capable of suctioning Unino-1 is swingably held by an arm 29a.

By using the polishing device configured in this manner, the vacuum chuck 29 adsorbs the UNINO-1, and first, the vacuum chuck 29 is swung on the outer circumference 20 to perform the primary polysinking of the UNINO-S1. By continuing to swing the vacuum chuck 29 on the inner peripheral portion 21, secondary polysink can be performed. However, even if this polishing device is used, the polishing process up to the third polysink cannot be automatically performed.

As mentioned above, although conventional polishing equipment can perform only primary polishing or primary and secondary polishing in a single-wafer type and automatically, it has not been possible to achieve ultra-integration of semiconductor devices. There was no polishing equipment that could automatically process haze-free, high-quality ultra-LST flexible silicon wafers in a single-wafer manner.

[Purpose of the invention]

The present invention improves the problems of the prior art described above, polishes wafers in a single-wafer manner and automatically, and provides scratch-free, scratch-free polishing.
The object of the present invention is to provide a polishing device that can easily and efficiently obtain a haze-free high-quality surface.

[Summary of the invention]

The configuration of the polishing apparatus according to the present invention is different from each other.

A polishing surface plate, a nozzle for supplying an abrasive onto the polishing surface plate, and are disposed opposite to the polishing surface plate.

The wafer holding means is capable of swinging on the polishing surface plate while holding a wafer, and the air cylinder is equipped with an air cylinder capable of pressing the wafer held by the wafer holding means onto the polishing surface plate. Also, a primary polishing mechanism for primary polishing.

A secondary polishing mechanism for a secondary polishing mechanism and a tertiary polishing mechanism for a tertiary polishing mechanism are arranged in that order, and the wafer is transported from the primary polishing mechanism side to the tertiary polishing mechanism side in that direction. A conveyor/cleaning device that can accommodate a belt, has a flow path that allows clean water to flow from the tertiary polishing mechanism side to the primary polishing mechanism side, and is equipped with a cleaning tool in the middle of the flow path. are arranged along the primary, secondary, and tertiary polishing mechanisms, and a cassette for unpolished wafers capable of storing a plurality of wafers is provided on the primary polishing mechanism side of the transport and cleaning device; A supply device is provided having a supply means capable of supplying wafers one by one from a cassette for wafers to be polished onto the conveyor belt, and a plurality of wafers are stored in the tertiary polisher groove side of the conveyance and cleaning device. a cassette for polished wafers; and a storage means capable of storing wafers that have undergone tertiary polishing by the tertiary polishing mechanism one by one from the conveyor belt into the cassette for polished wafers. a storage device is provided near each of the secondary polishing mechanisms, which grips the wafers that have moved on the conveyor belt and transfers them to the wafer holding means of the polishing mechanisms;
A robot is provided which can receive the wafer polished by the polishing mechanism from the holding means and return it onto the conveyor belt.

[Embodiments of the invention]

Hereinafter, the present invention will be explained by examples.

FIG. 1 is a schematic plan view showing a polishing apparatus according to an embodiment of the present invention, FIG. 2 is a schematic front view of the polishing apparatus according to FIG. 1, and FIG. FIG. 2 is a partial cross-sectional view showing the main parts of the cleaning device.

The outline of the polishing apparatus of this embodiment is that a primary polishing mechanism 7, a secondary polishing mechanism 8, and a tertiary polishing mechanism 9 are arranged side by side and can perform primary polishing, secondary polishing, and tertiary polishing, respectively. A transport/cleaning device 27 capable of cleaning the wafers 1 while transporting the wafers 1 one by one from the primary polishing mechanism 7 side to the tertiary polishing mechanism 9 side is installed in the primary polishing mechanisms 7 to 9. a tertiary polishing mechanism, disposed along 9;
A supply device 17 capable of supplying wafers l one by one is provided on the primary polishing mechanism 7 side of the transfer/cleaning device 27, and a tertiary polishing sink is provided on the tertiary polishing mechanism 9 side of the transfer/cleaning device 27. A storage device 18 is provided that can store the wafers 1 that have been completed up to 1 wafers one by one.
The wafer 1 conveyed on the conveyor belt 10 of No. 7 is gripped, and the wafer 1 is transferred to the vacuum chuck 2 of the primary polishing mechanism 7, the secondary polishing mechanism 8, and the tertiary polishing mechanism 9, respectively.
The wafer 1 polished by the polishing mechanism is placed in a vacuum chuck 2
This robot is equipped with robots lla, llb, and IIC that can receive the material from the robot and return it to the conveyor belt lo.

Next, the configuration of this polishing apparatus will be explained in detail.

7 is a primary polishing mechanism, and this primary polishing mechanism 7 is
A polishing plate 3 with a polygon cloth (not shown) glued to its surface, and a drive motor (
(not shown), a nozzle 5 for supplying the polishing agent 4 onto the polishing cloth of the polishing surface plate 3, and a nozzle 5 which is disposed so as to be movable up and down facing the polishing surface plate 3, while holding the wafer 1. Arm 2a that can swing on the policy surface plate 3
The wafer holding means has a vacuum chuck 2 attached to the tip thereof, and an air cylinder 6 capable of pressing the wafer 1 attracted to the vacuum chuck 2 onto a polishing surface plate 3.

The configurations of the secondary polishing mechanism 8 and the tertiary polishing mechanism 9 are also the same as that of the primary polishing mechanism 7, but the material of the polysync cloth bonded to the polishing surface plate 3 is different. For example, when polishing a silicon wafer, the polysink cloth for the primary polishing mechanism 7 is made of hard polyester fibers impregnated with polyurethane, and the polysink cloth for the secondary polishing mechanism 8 is made of polyurethane impregnated with a soft foamed polyurethane surface layer. A cloth made of polyester fiber is used for the tertiary polishing mechanism 9 in the secondary polishing mechanism 8.
Use the same cross as the one for each. The primary polishing mechanism 7, secondary polishing mechanism 8, and tertiary polishing mechanism 9 are arranged in that order.

Reference numeral 27 denotes a transport/cleaning device, which moves from the primary polishing mechanism 7 side to the tertiary polishing mechanism 9 side and transports the wafer 1 in that direction.

An endless conveyor belt 10 driven by a motor 10a can be stored therein, and clean water 19 can flow from the tertiary polishing mechanism 9 side to the primary polishing mechanism 7 side.
It has a channel 24 with a groove-shaped cross section, and is equipped with roll blanks ISA, 15b, 15c as cleaning tools in the middle of this channel 24, and is connected to the primary polishing mechanism 7, secondary polishing mechanism 8.
It is arranged along the tertiary polishing mechanism 9.

26 is a clean water production device, and 25 is a flow path 2 of a conveying/cleaning device 27 for the clean water 19 discharged from the clean water production device 26.
The clean water 19 sent to the tertiary polishing mechanism 9 side of 4 and flowing through the flow path 24 to the primary polishing mechanism 7 side is returned to the clean water production device 2.
This is a pump that circulates the water back to 6. By flowing the clean water 19 from the tertiary polishing mechanism 9 side to the primary polishing mechanism 7 side,
The cleanliness level when cleaning the wafer 1 after the tertiary polysinking can be increased.

Reference numeral 17 denotes a supply device disposed on the primary polishing mechanism 7 side of the transport and cleaning device 27, and this supply device 17 is vertically movable and can accommodate a plurality of wafers 1 in the vertical direction. A cassette 12 for wafers before polishing, and a wafer 1 is transferred from the cassette 12 for wafers before polishing to the conveyor belt 10.
Button 1 related to a supply means capable of supplying sheets one by one
4a, and the unpolished wafer cassette 12
is raised by one step each time one wafer 1 is fed by the pusher 14a, and is positioned so that the next wafer 1 can be fed.

Reference numeral 18 denotes a storage device disposed on the tertiary polishing mechanism 9 side of the transport/cleaning device 27, and this storage device 18 can store a plurality of wafers 1 in the vertical direction. A cassette 13 for polished wafers that can be moved up and down, and a tertiary polishing mechanism 9
A hand part (not shown) is used as a storage means for gripping the wafers 1 which have been moved on the conveyor belt 10 after finishing the tertiary poly//ing, and storing the wafers one by one into the wafer cassette 13 after polishing. gripping device 14b equipped with
The cassette 13 for polished wafers includes:
When one wafer 1 is stored by the gripping device 14b, i
/i: It is positioned so that it can move down one step at a time and store the primary wafer 1.

11a was arranged near the primary polishing mechanism 7.

This robot 11a has a node part 22a with a visual function attached to the tip of an arm 23a.
When the wafer 1 moving on the conveyor belt 10 is visually detected, the conveyor belt 10 is stopped, the wafer 1 is gripped by the nib section 22a, and is placed under the vacuum chuck 2 of the primary polishing mechanism 7. Transported to that Unino 1
The wafer 1 can be transferred to the vacuum chuck 2, and the wafer 1 that has undergone the primary polishing by this primary polishing mechanism 7 can be transferred to the vacuum chuck 2.
can be received from the vacuum chuck 2 by the hand portion 22a and returned onto the conveyor belt 10.

The robots llb and IIC each have a secondary polishing mechanism 8,
It is disposed near the tertiary polishing mechanism 9, and its configuration is the same as that of the robot 11a.

Although not shown, this polishing apparatus includes the respective secondary polishing mechanisms 7 to 9. Sparrow feeding and cleaning device 27. Supply device 17, storage device 18. Robot lla, llb.

A control device is equipped that can control the operation of 11c.

7a, 8a, and 9a are clean rooms in which a primary polishing mechanism 7, a secondary polishing mechanism 8, and a tertiary polishing mechanism 9 are housed, respectively, and to which ducts 16a, 16b, and 16c are connected, These ducts 16a, 16b.

Beyond 16C, there is a cleaning device (not shown) that can independently clean the air in each of the clean rooms 73 to 9a.
is installed.

The operation of the polishing apparatus configured in this way will be explained.

As the polishing agent 4, for example, in the case of polishing 7 Recon Waist, 11 in alkaline pH is used for the primary polishing mechanism 7.
For the secondary polishing mechanism 8, colloidal silica of pHHIO, which is slightly less alkaline than that for the primary polishing mechanism 7, is used.
Colloidal silica No. 25 and a polishing agent prepared by dispersing fine silica particles in ammonia water for the tertiary polishing mechanism 9 are used, respectively.

First, the control device includes the number of wafers to be polished, the polishing pressure in each polishing mechanism 7 to 9, the polishing time, the rotation speed of the Bolin surface plate 30, the swing angle of the arm 2a of the wafer holding means, and the swing per time. The number of movements and the moving speed of the conveyor belt 10 are set.

When the polishing device is turned on here, the pump 25 rotates, and the clean water 19 coming out of the clean water production device 26 flows through the flow path 24 of the conveying/cleaning device 27 from the tertiary polishing mechanism 9 side to the primary polishing mechanism 7. After flowing to the side, the water returns to the clean water production device 26 and circulates again. The conveyor belt 10 starts moving to the right (right side in FIG. 1) at the set moving speed. Each polishing mechanism 7~
The cleaning devices connected to the ducts 16a to 16CK of the clean rooms 7a to 9a of 9 are operated, and each
The air in a to 9a is kept clean independently.

The bushing 14a moves forward, and the cassette 12 for wafers before polishing
One wafer 1 is pushed out from inside and placed on the conveyor belt 10, and the wafer 1 is passed on the conveyor belt 10 with clean water 1.
It is sent to the right side while being washed at step 9. The cassette 12 for wafers to be polished rises by one stage. When the primary polishing mechanism 70 (robot) located at the initial position (position shown in FIG. 1) K visually detects the wafer 1 being conveyed on the conveyor belt 10, the conveyor belt 10 stops. .

Then, the wafer 1 is transferred to the hand portion 22 of the robot
The arm 23a of the robot 11a rotates in the direction of the arrow. When the wafer 1 comes under the vacuum chuck 2, the arm 23a stops rotating. vacuum chuck 2
The robot 11a descends, and the Unino 1 is attracted to the vacuum chuck 2 and separated from the hand portion 22a of the robot 11a. The arm 23a of the robot lla rotates and returns to the initial position. The vacuum chuck 2 is pressed by the air cylinder 6, and the Unino 1 is pressurized on the polishing surface plate 3 at a set polishing pressure (the polishing pressure for this primary polishing is 0.2 kgf/cm" or more). Nozzle 5 The polishing agent 4 is supplied from the polishing plate 3, and the polishing plate 3 rotates at a set rotational speed.

The arm 2a of the wafer holding means performs a swinging motion at a set swinging angle and number of swings, and primary polysynching of the surface of the UNINO-1 is performed. In this primary polysink, the wafer 1 is polished by 10 to 30 μm.

When the set polishing time has elapsed, the rotation of the polishing surface plate 3 and the swinging movement of the arm 2a of the wafer holding means stop, the supply of the polishing agent 4 from the nozzle 5 also stops, and the vacuum chuck 2 is raised by the arm 2a. and return to its initial position. The arm 23a of the robot)lla rotates, and the hand portion 22a comes under the vacuum chuck 2 and stops. The vacuum chuck 2 descends, and the wafer 1 that has completed the primary polysink is transferred to the robot 1.
It is held by the hand portion 22a of 1a. The vacuum chuck 2 returns to the initial position again. The arm 23a of the robot) 11a rotates, and when the wafer 1 is placed on the conveyor belt 10, the robot stops its rotation. If the conveyor belt 10 is moving at this time, it is stopped. The wafer 1 is separated from the hand portion 22a of the robot 11a and placed on the conveyor belt 10. At the same time, the pusher 14a moves forward, and the next wafer 1 is pushed out from the unpolished wafer cassette 12.
It is placed on the conveyor belt 10. The conveyor belt 10 moves and the roll brush 15a rotates.

Both wafers 1 are transferred to the right side on the conveyor belt 101C. That is, the wafer 1 that has undergone primary polishing is washed with clean water 19, the surface of which is further cleaned with a roll brush 15a, and then transferred to the secondary polishing mechanism 8 side.

On the other hand, the newly supplied wafer 1 is sent to the right side while being cleaned with clean water 19. Then, in the same way as before, when the robot 11a detects the wafer 1, the conveyor belt 10 stops, and the wafer 1 is gripped by the hand part 22a of the robot and transported to the primary polishing mechanism 7, where it is Next polysynced. Regarding the wafer 1 transferred to the secondary polishing mechanism 8 side, when the robot 11b detects the wafer 1, if the conveyor belt 10 is moving, the robot 11b stops it, and the robot The wafer 1 is held in place and transported to the secondary polishing mechanism 8, where it is subjected to secondary polishing in the same manner as in the primary polishing mechanism 7. The polishing pressure of this secondary polishing sink is lower than the polishing pressure of the primary polishing.

The polishing time is still short.

The wafer 1 that has undergone the secondary polysynchronization is gripped by the robot 11b and carried onto the conveyor belt 10. If the conveyor belt 10 is moving at this time, it is stopped and the wafer 1 is placed on the conveyor belt 10. The conveyor belt 10 moves, the roll plane 15b rotates, and the wafer 1 is washed with clean water 19, cleaned by the roll brush 15b, and transferred to the tertiary polishing mechanism 9 side. robot 11c
When the robot 11C detects the wafer 1, if the conveyor belt 10 is moving, it is stopped, the robot 11C grasps the wafer 1 transferred on the conveyor belt 10, and transfers it to the tertiary polishing mechanism 9. It is then transported to a third polishing station, where it is subjected to tertiary polishing. The polishing pressure of this tertiary polishing is lower than the polishing pressure of the secondary polishing, and the polishing time is still shorter.

The wafer 1 that has undergone the tertiary polysynchronization is gripped by the robot 11C and carried onto the conveyor belt 10. If the conveyor belt 10 is moving at this time, it is stopped and the wafer 1 is placed on the conveyor belt 10. The conveyor belt 10 moves, the roll brush 15c rotates, and the wafer 1 is washed with clean water 19, cleaned by the roll brush 15c, and transferred to the right side.

If the gripping device 14b is activated and the conveyor belt 10 is moving at this time, it is stopped), the hand section grips the wafer 1 that has reached the tertiary polysink on the conveyor belt 10, and polishes the wafer 1. The wafer is stored in the wafer cassette 13. Then, the cassette 13 for wafers after polishing is lowered by one stage. During this time, the wafers 1 are sequentially fed one by one from the unpolished wafer cassette 12 onto the conveyor belt 10 as described above, and each polishing process is performed. When the set number of wafers 1 are stored in the wafer cassette 13 after polishing, the polishing device becomes 0FFK, and the pump 25
．． Conveyor belt 10. The cleaning device stops, and a desired number of polished wafers 1 are obtained.

According to the embodiment described above, the wafer 1 is primary.

Can perform consistent automatic polishing with secondary and tertiary polysink.

Scratch-free 2 Haze-free wafers 1 can be automatically stored from the pre-polishing wafer cassette 12 to the post-polishing evaporation cassette 13, so high-quality wafers for large-diameter ultra-LS wafers can be stored. Easily and efficiently
Moreover, it has the effect that it can be obtained at a high yield.

There are still polishing mechanisms 7 and 8 for primary, secondary, and tertiary polysinks.
．． 9 is integrated, there is no need to provide a conventional large-scale polishing device in each process, and the space for cleaning equipment between each process is also reduced, resulting in an extremely large space-saving effect.

〔Effect of the invention〕

As explained in detail above, according to the present invention, there is provided a polishing apparatus that can polish wafers in a single-wafer manner and automatically, thereby easily and efficiently producing scratch-free, haze-free, high-quality wafers. can be provided.

[Brief explanation of drawings]

1 is a schematic plan view showing a polishing apparatus according to an embodiment of the present invention, FIG. 2 is a schematic front view of the polishing apparatus according to FIG. 1, and FIG. FIG. 4 is a partial cross-sectional view showing the main parts of the transport and cleaning device. FIG. 5 is a schematic side view showing an example of a conventional wafer polishing apparatus (for primary polishing).
FIG. 3 is a schematic plan view illustrating a first-order polysink and a second-order boring. 1... Wafer, 2... Vacuum chuck, 2a... Arm, 3... Holing surface plate, 4... Polishing agent, 5...
Nozzle, 6... Air cylinder, 7... Primary polishing mechanism, 8... Secondary polishing mechanism, 9... Tertiary polishing mechanism, 1o
. . . Conveyor belt, 11a, llb, 1lc-.
...gripping device, 15 a, 15 b, l 5
C---o-/l/brush, 17--supply device, 18
... Storage device, 19 ... Clean water, No. 24 L
gigantic]

Claims (1)

[Claims] 1. Each of them includes a polishing surface plate, a nozzle for supplying a polishing agent onto the polishing surface plate, and is arranged opposite to the polishing surface plate and swings on the polishing surface plate while holding the wafer. a primary polishing mechanism for a primary polishing sink, and a secondary polishing mechanism, comprising: a wafer holding means capable of holding the wafer; an air cylinder capable of pressing the wafer held by the wafer holding means onto the polishing surface plate; A secondary polishing mechanism for the secondary polishing mechanism and a tertiary polishing mechanism for the tertiary polishing mechanism are arranged in that order, and a conveyor belt that moves from the primary polishing mechanism side to the tertiary polishing mechanism side and transports the wafer in that direction is housed. A conveyance/cleaning device having a flow path through which clean water can flow from the tertiary polishing mechanism side to the primary polishing mechanism side, and equipped with a cleaning tool in the middle of this flow path, is connected to the primary polishing mechanism. , a cassette for unpolished wafers that can store a plurality of wafers, and a cassette for unpolished wafers, which is disposed along the secondary and tertiary polishing mechanisms, and is provided on the primary polishing mechanism side of this transport and cleaning device. A supply device having a supply means capable of supplying wafers one by one from a cassette onto the transport belt can be provided, and a plurality of wafers can be stored on the tertiary polishing mechanism side of the transport and cleaning device. A storage device comprising a cassette for polished wafers and a storage means capable of storing wafers that have undergone tertiary polishing by the tertiary polishing mechanism one by one from the conveyor belt into the cassette for polished wafers. is provided near each of the secondary polishing mechanisms, grips the wafer that has moved on the conveyor belt, transfers it to the wafer holding means of the polishing mechanism, and removes the wafer polished by the polishing mechanism from the wafer holding means. A polishing apparatus characterized in that a robot is provided that can receive the materials and return them onto the conveyor belt.