JP7744796B2 - Polishing Equipment - Google Patents

Description

The present invention relates to a polishing device for polishing workpieces such as semiconductor wafers, and in particular to a polishing device equipped with an indexing mechanism that allows for miniaturization.

Conventionally, there are polishing devices that perform polishing processes on semiconductor wafers and the like, such as CMP (Chemical Mechanical Polishing). Known polishing devices of this type include those equipped with an indexing mechanism that transports workpieces such as semiconductor wafers to a processing position on a polishing table.

For example, Patent Document 1 discloses a polishing device having an index head whose center is journaled on a hollow shaft that can rotate forward and backward. Below the index head, multiple chuck mechanisms are provided on the same circumference around the hollow shaft of the index head, which suction-hold wafers from above. The wafers held by the chuck mechanisms are transported to the position where the polishing process will take place by the rotation of the index head, and as they rotate around the rotation axis of the chuck mechanisms, they are pressed against a rotating polisher below and polished.

For example, Patent Document 2 discloses a semiconductor substrate polishing apparatus having an index-type rotary table with multiple substrate holder tables arranged on top. The index-type rotary table rotates to transport the workpiece held on the upper surface of the substrate holder table. The substrate holder tables then rotate around the spindles connected to them as their rotation axes, and a rotating polishing pad descends from above the rotating workpiece, rubbing against the upper surface of the workpiece to polish it.

Japanese Patent Application Laid-Open No. 2000-24916 JP 2008-221416 A

However, the polishing apparatus equipped with the index mechanism of the above-mentioned conventional technology had some areas that needed improvement in order to improve productivity of semiconductor wafers and the like, as well as to reduce the size of the apparatus.

Specifically, in conventional indexing mechanisms, a support pillar is provided at the center of a rotating index, such as an index head or index table, which acts as a rotation axis to support the index. As a result, the dimensions of the index inevitably increase by an amount equivalent to the diameter of the pillar, requiring a large area for the indexing mechanism and resulting in a larger polishing device.

Furthermore, in a configuration in which the center of the index is supported by a support, the distance the workpiece moves when the index is rotated to move it becomes longer. In other words, the radius of rotation of the workpiece when it moves becomes larger by an amount equivalent to the diameter of the support provided in the center, and the rotation circumference becomes longer. As a result, it has been difficult to reduce the time it takes to move the workpiece and improve productivity.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a polishing device equipped with a small, highly efficient indexing mechanism, which allows for the device to be made smaller and for productivity to be improved.

The polishing apparatus of the present invention comprises a polishing table that rotates while holding an abrasive cloth on its upper surface , a chuck that adsorbs a workpiece to its lower surface and rotates, causing the lower surface of the workpiece to slide against the upper surface of the abrasive cloth, an index that rotates to transport the workpiece held by the chuck together with the chuck , a base table on top of which the polishing table is arranged, and a column that is arranged on top of the base table and supports the index , and is characterized in that a support member that supports the index so that it can rotate freely is provided on the peripheral edge of the index.

The polishing device of the present invention comprises a polishing table that holds and rotates an abrasive cloth, a chuck that rotates while adsorbing a workpiece, and an index that rotates to transport the workpiece held by the chuck. The periphery of the index is provided with a support member that rotatably supports the index. This configuration eliminates the need to provide a support pillar or the like in the center of the index, allowing for a more compact polishing device. Furthermore, the smaller index shortens the distance the workpiece must be transported, enabling more efficient workpiece transport by the index.

Furthermore, according to the polishing device of the present invention, a power transmission member that transmits rotational power from the drive means to the index may be provided on the peripheral edge of the index. This eliminates the need to provide a rotational shaft or the like in the center of the index to transmit rotational power to the index. This results in a compact, highly efficient index mechanism, making it possible to miniaturize the polishing device and improve productivity.

Furthermore, according to the polishing device of the present invention, the power transmission member may include a belt clamp provided on the periphery of the index and a belt with both ends fixed to the belt clamp. This configuration provides a power transmission member that can be easily attached to the periphery of the index, efficiently transmits power from the drive means, and efficiently rotates a small index that does not have a support pillar in the center.

Furthermore, according to the polishing device of the present invention, the power transmission member may include a pulley provided on the periphery of the index and having a concave-convex tooth profile formed on the transmission surface, and a belt meshing with the pulley. This configuration allows for efficient transmission of power from the drive means, enabling efficient rotation of a small index that does not have a support pillar in the center.

The power transmission member may include a large gear provided coaxially with the index around the periphery of the index, and a small gear meshing with the large gear. This configuration allows the power from the drive mechanism to be efficiently transmitted via a gear mechanism, enabling efficient rotation of a small index that does not have a support pillar in the center.

The polishing apparatus of the present invention further comprises a base table on which the polishing table is disposed, and a column disposed above the base table and supporting the index. The polishing cloth may be held on the upper surface of the polishing table, and the workpiece may be attracted to the lower surface of the chuck, with the lower surface of the workpiece sliding against the upper surface of the polishing cloth. This configuration makes it possible to provide a large-diameter polishing table that can precisely hold a polishing cloth with a larger diameter than the workpiece held in the chuck, while preventing the polishing apparatus from becoming too large. This allows the workpiece to be efficiently transported using a small index with no central support, and the workpiece can be polished with high precision using a large-diameter polishing cloth.

Furthermore, according to the polishing device of the present invention, the support member may be a bearing having an inner ring fixed to the periphery of the index, an outer ring fixed to the column side, and cylindrical rolling elements arranged between the inner ring and the outer ring so that they intersect alternately at right angles. This allows for line contact between the inner ring and the outer ring and the rolling elements, allowing for complex loads such as radial loads, axial loads, and moments to be received simultaneously with small elastic displacement, and the index can be supported to rotate with high precision. Therefore, without providing a support pillar in the center of the index, workpieces can be transported accurately using a small index, enabling highly efficient polishing.

1 is a plan view showing a schematic configuration of a polishing device according to an embodiment of the present invention. 1 is a side view showing a schematic configuration of a polishing device according to an embodiment of the present invention. 1A is a cross-sectional view showing an outline of a bearing that supports an index of a polishing device according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line AA. 1 is a plan view showing a state in which a workpiece is received from a load cassette of a polishing apparatus according to an embodiment of the present invention. FIG. 1 is a plan view showing a state in which a workpiece is received on a load tray of a polishing device according to an embodiment of the present invention. FIG. 1 is a plan view showing a state in which a workpiece is transferred to a chuck of a polishing device according to an embodiment of the present invention; 1 is a plan view showing a state during polishing of a polishing device according to an embodiment of the present invention. FIG. 1 is a plan view showing a state in which a workpiece is received by an unload tray of a polishing device according to an embodiment of the present invention. FIG. 1 is a plan view showing a state in which a workpiece is handed over from an unload tray of a polishing device according to an embodiment of the present invention; 10 is a plan view showing a state in which a workpiece has been transferred to an unload cassette of the polishing apparatus according to the embodiment of the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A polishing apparatus according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.
FIG. 1 is a plan view showing a schematic configuration of a polishing apparatus 1 according to an embodiment of the present invention.
1, the polishing apparatus 1 is an apparatus for polishing the surface of a substantially substrate-shaped workpiece W. Specifically, the workpiece W is, for example, a semiconductor substrate, and the polishing apparatus 1 is an apparatus for performing, for example, chemical mechanical polishing (CMP). That is, the polishing apparatus 1 is used to finish the surface of the semiconductor or the like that forms the workpiece W, or various coatings or the like formed on the surface of the semiconductor or the like, to a highly flat surface.

The polishing device 1 has a polishing table 2 that holds an abrasive cloth 9 for polishing the workpiece W, a chuck 3 that holds the workpiece W, an index 4 that transports the workpiece W held by the chuck 3, and a workpiece transport mechanism 5 that transports the workpiece W to the chuck 3.

FIG. 2 is a side view showing a schematic configuration of the polishing device 1. As shown in FIG.
1 and 2, the polishing table 2 is a device that suction-holds and rotates a polishing cloth 9 for polishing a workpiece W. Specifically, the polishing table 2 is substantially circular, is mounted on a base frame 10 so as to be horizontally rotatable, and is driven to rotate by a driving means (not shown) with the polishing cloth 9 held on a holding surface at the top. The polishing cloth 9 may be vacuum-sucked onto the holding surface of the polishing table 2 using, for example, a pressure reducing device (not shown).

The polishing cloth 9 is a cloth member used to polish the workpiece W. For example, a foamed polyurethane sheet, a nonwoven fabric made of synthetic fibers, or other felt may be used as the polishing cloth 9.

The chuck 3 is a mechanism that suction-holds and rotates the workpiece W to be polished. The chuck 3 has a roughly circular holding surface that holds the workpiece W. The chuck 3 is provided with a rotation shaft 14 that extends vertically, i.e., perpendicular to the holding surface, and is supported by the index 4 via the rotation shaft 14.

The holding surface of the chuck 3 that holds the workpiece W is configured to rotate freely around a rotation axis 14 located approximately in the center. A chuck motor 15 is provided above the index 4 as a drive means for rotating the chuck 3. The chuck 3 is driven to rotate by the chuck motor 15. In other words, the workpiece W rotates horizontally around the rotation axis 14 of the chuck 3.

The chuck 3 has a smaller diameter than the polishing table 2. In other words, the polishing table 2 can hold with high precision a polishing cloth 9 with a larger diameter than the workpiece W held by the chuck 3. By providing such a large-diameter polishing table 2, the polishing device 1 can polish the workpiece W with high precision using a large-diameter polishing cloth 9 while preventing the overall device size from increasing by using a small index 4 with no central support.

The power transmission means that transmits the rotational power of the chuck motor 15 to the chuck 3 is, for example, a V-belt, timing belt, or any other type of belt mechanism. Above the index 4, there are provided a pulley 16 connected to the rotation shaft 14, a pulley 17 fixed to the output shaft of the chuck motor 15, and a belt 18 looped around the pulley 16 and pulley 17. The chuck motor 15 may also be a direct drive motor that drives the chuck 3 without using a power transmission means.

The polishing device 1 also has an air cylinder 19 as a feeding means for vertically feeding the holding surface of the chuck 3. The air cylinder 19 is located above the index 4 and feeds the chuck 3 vertically, and during the polishing process, it presses the workpiece W held by the chuck 3 against the polishing surface of the polishing cloth 9.

In the polishing device 1, the workpiece W is polished by bringing the polishing cloth 9 into contact with the workpiece W and moving them relative to each other. More specifically, during the polishing process, the surface to be polished of the workpiece W, i.e., the lower surface, rotates around the rotation axis 14 of the chuck 3 and comes into contact with the polishing surface, i.e., the upper surface, of the polishing cloth 9, which rotates around the rotation axis of the polishing table 2. The surface to be polished of the workpiece W is then pressed against the polishing surface of the polishing cloth 9. This causes the surface to be polished of the workpiece W to be polished.

The index 4 is an indexing device that rotates to transfer the workpiece W held in the chuck 3 to the polishing position 40. Specifically, the index 4 is approximately circular and is supported by a column 11 located above the base frame 10 so that it can rotate horizontally.

More specifically, above the base frame 10, a column 11 is formed, which has a support 13 erected from the base frame 10 and an upper plate 12 supported by the support 13. The index 4 is rotatably supported on the upper plate 12 of the column 11.

The index 4 is provided with two chucks 3, and the index 4 rotates around its central axis while supporting the chucks 3. By rotating the index 4, the workpiece W is transported from the loading position 41 to the polishing position 40 while held by the chucks 3, or vice versa.

Now, the rotation mechanism of the index 4 will be described in detail. A bearing 20 is provided on the periphery of the index 4 as a support member that rotatably supports the index 4. Specifically, the periphery of the index 4 is rotatably supported on the upper plate 12 via the bearing 20.

As the index 4 is supported at its periphery by the bearings 20, there is no need to provide a support pillar or the like in the center of the index 4 to support it. This allows the polishing device 1 to be made more compact. Furthermore, the smaller size of the index 4 shortens the transport distance of the workpiece W, allowing the index 4 to transport the workpiece W more efficiently. This increases the productivity of the workpiece W produced by the polishing device 1.

The column 11 is also provided with an index motor 24, which is a driving means for rotating the index 4 and transporting the workpiece W. The rotational power of the index motor 24 is transmitted to the periphery of the index 4.

More specifically, belt clamps 25 are provided around the periphery of the index 4 to secure both ends of a belt 27, which serves as a power transmission member that transmits rotational power from the index motor 24 to the index 4.

A pulley 26 is fixed to the output shaft of the index motor 24. The pulley 26 fixed to the output shaft of the index motor 24 and a belt clamp 25 provided on the periphery of the index 4 are connected via a belt 27 so that power can be transmitted.

By providing a mechanism for transmitting rotational power to the periphery of the index 4 in this way, it is not necessary to provide a rotational shaft or the like in the center of the index 4 to transmit rotational power to the index 4, as mentioned above. This results in a compact, highly efficient index mechanism, making it possible to reduce the size of the polishing device 1 and improve productivity.

The belt clamp 25, pulley 26, and belt 27 that transmit the power of the index motor 24 to the periphery of the index 4 can be, for example, a V-belt, a timing belt, or any other type of belt mechanism.

For example, the pulley 26, a power transmission member that transmits rotational power to the index 4, may be a timing pulley with a concave-convex tooth profile such as a trapezoidal tooth profile formed on the transmission surface, the belt 27 may be a timing belt that meshes with the pulley 26, and the belt clamp 25 may be a clamp that secures both ends of the timing belt.

This configuration allows the power from the index motor 24 to be transmitted efficiently and accurately, allowing the small index 4, which has no central support, to be rotated efficiently and with high precision to an accurate position.

In addition, a pulley (not shown) that meshes with the belt 27 may be provided coaxially with the index 4 and bearing 20 on the periphery of the index 4 as a power transmission member that transmits rotational power from the index motor 24 to the index 4.

The power transmission member that transmits the rotational power from the index motor 24 to the index 4 may also be a gear mechanism. For example, a large gear (not shown) with teeth formed on a pitch circle coaxial with the index 4 and bearing 20 may be provided on the periphery of the index 4 as the power transmission member. The large gear provided on the periphery of the index 4 meshes with a small gear (not shown) provided on the output shaft of the index motor 24 directly or via another gear, allowing for free power transmission.

The polishing apparatus 1 has a polishing liquid supply device (not shown) that supplies polishing liquid to the polishing cloth 9 during the polishing process. During the polishing process, the polishing liquid supplied from the polishing liquid supply device is supplied to the polishing surface via the polishing cloth 9. The polishing liquid may be, for example, a solution such as pure water, alkaline aqueous solution, or acidic aqueous solution, in which abrasive grains such as silicon oxide (silica), aluminum oxide (alumina), cerium oxide (ceria), or manganese oxide are mixed.

The polishing apparatus 1 also has a dressing device (not shown) that dresses the polishing surface of the polishing cloth 9. The dressing device has a dresser (not shown) that removes clogging from the polishing cloth 9 and sharpens it. The dresser is, for example, a diamond dresser with diamond abrasive grains electroplated with nickel (Ni).

The dresser may also be made of, for example, synthetic resin. The synthetic resin material that makes up the dresser is preferably an industrial plastic (engineering plastic) with high strength and excellent heat resistance, such as polyamide (PA) or polyether ether ketone (PEEK). Specifically, the dresser may be a nylon brush or a PEEK brush.

The dressing device may also include a high-pressure water generator that supplies high-pressure water, and a high-pressure water injection nozzle that injects high-pressure water toward the polishing surface of the polishing cloth 9 or the dressing surface of the dresser. The pressure of the high-pressure water supplied from the high-pressure water generator is, for example, 1 to 15 MPa. This configuration allows the polishing surface of the polishing cloth 9 or the dressing surface of the dresser to be effectively cleaned, demonstrating excellent dressing performance.

The polishing device 1 is provided with a load cassette 37 for supplying the workpiece W to be processed into the device, and an unload cassette 38 for removing the workpiece W from the device after polishing.

The load cassette 37 and unload cassette 38 are cassettes that can accommodate multiple workpieces W. Furthermore, the load cassette 37 and unload cassette 38 are configured to be removable from the polishing apparatus 1.

The workpiece transport mechanism 5 transports the workpiece W to be processed to the chuck 3. Specifically, the workpiece transport mechanism 5 transports the workpiece W to be processed that is stored in the load cassette 37 to the chuck 3, and transports the workpiece W after polishing has been completed from the chuck 3 to the unload cassette 38.

The workpiece transport mechanism 5 includes a robot 36 that transports workpieces W to and from the load cassette 37 and unload cassette 38, a load tray 30 that sends the workpieces W received from the robot 36 to the chuck 3, and an unload tray 32 that receives the workpieces W from the chuck 3 and hands them over to the robot 36.

The robot 36 is a transport robot that is controlled by a control device (not shown) and driven by a driving means (not shown) to automatically transport the workpiece W.
The robot 36 takes out the workpiece W stored in the load cassette 37 and sends it to the load tray 30. The robot 36 also receives the workpiece W that has been polished from the unload tray 32 and stores it in the unload cassette 38.

The load tray 30 is a tray for sending the workpiece W to the chuck 3. More specifically, the load tray 30 receives the workpiece W to be processed that has been transported from the robot 36, and sends and hands over the workpiece W to the chuck 3.

The load tray 30 is supported on horizontally extending rails 34 provided on the top of the base frame 10 and moves along the rails 34. Specifically, the load tray 30 is driven by a drive unit (not shown) and can move back and forth between a reference position 31 where it receives the workpiece W from the robot 36 and a loading position 41 where it hands over the workpiece W to the chuck 3.

The unload tray 32 is a tray for transferring the workpiece W from the chuck 3 to the robot 36. Specifically, the unload tray 32 receives the polished workpiece W from the chuck 3 at the loading position 41, and then transports the workpiece W to the reference position 33 to transfer it to the robot 36.

The unload tray 32 is supported by rails 34 and moves along the rails 34. Specifically, the unload tray 32 is driven by a drive unit (not shown) and can move back and forth between a reference position 33 where the workpiece W is handed over to the robot 36 and a loading position 41 where the workpiece W is received from the chuck 3.

In this way, the load tray 30 and unload tray 32 are positioned symmetrically on the left and right, so that they are each able to move back and forth along the rails 34 and are at approximately the same distance from the chuck 3.

The reference position 31 where the load tray 30 receives the workpiece W from the robot 36 is located to the left of the loading position 41, which is approximately in the center of the polishing apparatus 1, in Figure 1, i.e., on the left side of the polishing apparatus 1. On the other hand, the reference position 33 where the unload tray 32 hands over the workpiece W to the robot 36 is located to the right of the loading position 41, i.e., on the right side of the polishing apparatus 1. Note that the arrangement of the load tray 30 and unload tray 32 may be reversed from the above.

A lower partition wall 28 and an upper partition wall 29 are provided between the load tray 30 and unload tray 32 and the polishing table 2. The lower partition wall 28 and the upper partition wall 29 are walls that prevent polishing debris and the like from the workpiece W being polished above the workpiece polishing table from scattering toward the load tray 30 and unload tray 32 during the polishing process.

Specifically, the lower partition 28 is fixed to the top of the base frame 10. The upper end of the lower partition 28 is located higher than the upper surface of the polishing table 2. The upper partition 29 is fixed to the bottom of the index 4, and the lower end of the upper partition 29 is close to the upper end of the lower partition 28. The upper partition 29 rotates together with the index 4. This prevents contamination of the workpiece W before and after polishing due to scattering of polishing debris, etc., in a configuration in which the workpiece W is transported by rotation of the index 4.

The polishing device 1 may also have a chuck cleaning device (not shown) that cleans the holding surface of the chuck 3. The chuck cleaning device is a component that removes polishing debris and the like that has adhered to the chuck 3 during the polishing process before holding the next workpiece W to be processed, and is provided, for example, on top of the base frame 10. The chuck cleaning member (not shown) of the chuck cleaning device is, for example, a brush-like member made of synthetic resin, such as a nylon brush.

The chuck cleaning device may also be provided with a high-pressure water spraying means (not shown) that sprays high-pressure water onto the holding surface of the chuck 3 to clean the chuck 3. The high-pressure water sprayed onto the chuck 3 may be, for example, pure water, an alkaline aqueous solution, or an acidic aqueous solution.

FIG. 3A is a cross-sectional view showing an outline of the bearing 20 that supports the index 4, and FIG. 3B is a cross-sectional view taken along line AA shown in FIG. 3A.
3A and 3B, the bearing 20 serving as a support member for supporting the index 4 may be, for example, a cross roller bearing. More specifically, the bearing 20 has an inner ring 21 fixed to the periphery of the index 4, an outer ring 22 fixed to the column 11 side, and rollers 23, which are substantially cylindrical rolling elements, arranged alternately between the inner ring 21 and the outer ring 22 so as to intersect at right angles.

By using a cross roller bearing as the bearing 20 that supports the index 4 in this way, the support member can be made smaller and the index 4 can rotate with high precision.

In other words, due to the line contact between the inner ring 21, outer ring 22, and rollers 23, the bearing 20 is small yet can simultaneously withstand complex loads such as radial loads, axial loads, and moments that act on the index 4 during the workpiece W (see Figure 2) transfer and polishing processes, with little elastic displacement.

This allows the column 11 to support the index 4 via the bearing 20, allowing it to rotate with high precision. Therefore, without providing a support pillar in the center of the index 4, the workpiece W can be transported accurately and stably using a small index 4, allowing for highly efficient and precise polishing.

Next, the operation of the polishing apparatus 1 for transporting and polishing the workpiece W will be described with reference to FIGS.
FIG. 4 is a plan view showing a state in which the workpiece W is received from the load cassette 37. As shown in FIG.
4, first, a load cassette 37 containing workpieces W to be polished is attached to the polishing apparatus 1. As described above, the load cassette 37 may contain a plurality of workpieces W. The work of attaching the load cassette 37 to the polishing apparatus 1 may be performed by an operator, or may be performed automatically by another transport device (not shown) or the like.

FIG. 5 is a plan view showing a state in which the workpiece W is received by the load tray 30. As shown in FIG.
4 and 5, the workpiece W stored in the load cassette 37 is taken out by the robot 36 and transferred to the load tray 30. That is, the workpiece W is placed on top of the load tray 30 by the robot 36. At this time, the load tray 30 is at the reference position 31 on the left side of the index 4 for receiving the workpiece W.

FIG. 6 is a plan view showing a state in which the workpiece W is transferred to the chuck 3. As shown in FIG.
With the workpiece W held on the load tray 30 as shown in Fig. 5, the load tray 30 moves to a loading position 41 toward the center of the polishing apparatus 1, and the workpiece W is transferred to one of the chucks 3a as shown in Fig. 6. At this time, the unload tray 32 is located at a reference position 33 on the right side of the polishing apparatus 1 for transferring the workpiece W.

More specifically, the loading position 41 is below one of the chucks 3a that is not currently being polished and is supported by a rotatable index 4. That is, the workpiece W is sent below the holding surface of the chuck 3a that is not currently being polished, which is radially away from the rotation area of the polishing table 2.
At this time, the other chuck 3b at the polishing position 40 on the polishing table holds another workpiece W (not shown), and the workpiece W is being polished.

The workpiece W sent to the loading position 41 is handed over to the upper chuck 3a and held by suction. That is, the chuck 3a is moved by the air cylinder 19 (see Figure 2) so that it abuts against the workpiece W below the holding surface and adsorbs the workpiece W. The chuck 3a holding the workpiece W is then moved upward to a height at which the index 4 can rotate, specifically, to a height at which the workpiece W can rotate past the lower partition wall 28.

FIG. 7 is a plan view showing the state of the polishing device 1 during polishing.
As shown in Fig. 6, after the workpiece W is transferred to the chuck 3a at the loading position 41, as shown in Fig. 7, the index 4 rotates 180 degrees with its peripheral edge supported by the bearing 20. As a result, the chuck 3a and the workpiece W held by the chuck 3a are sent from the loading position 41 to the polishing position 40.
At this time, the other chuck 3b on the polishing table is moved from the polishing position 40 to the loading position 41 while holding the workpiece W (not shown) that has been polished.

The chuck 3a is then moved downward, and the lower surface of the workpiece W, which is the surface to be polished, slides against the upper surface, which is the polishing surface, of the polishing cloth 9 held on the polishing table 2. Then, the polishing process of the workpiece W is carried out.

Specifically, the workpiece W is pressed against the chuck 3a by the air cylinder 19 (see Figure 2), and the chuck 3a is rotated by the chuck motor 15 (see Figure 2), which in turn rotates the polishing table 2 via a driving means (not shown). The surface of the workpiece W to be polished is polished by the relative movement between the workpiece W and the polishing cloth 9.

Once the polishing process is completed, the chuck 3a is sent upward while still holding the workpiece W. That is, the chuck 3a is raised to a height where the workpiece W is higher than the lower partition wall 28 and the index 4 can rotate.

FIG. 8 is a plan view showing a state in which the unload tray 32 receives the workpiece W. As shown in FIG.
As shown in FIG. 8, after the polishing process is completed and the chuck 3a is raised, the index 4 rotates around its center.

Specifically, the index 4 is driven by the index motor 24 to rotate 180 degrees in the reverse direction while its peripheral edge is supported by the bearing 20. As a result, the workpiece W after polishing is transferred from the polishing position 40 to a loading position 41 outside the rotation area of the polishing table 2.
At this time, another workpiece W (not shown) to be polished next is sent from the loading position 41 to the polishing position 40 while being held by the other chuck 3b.

Here, the unload tray 32 moves to the loading position 41 to receive the workpiece W from the chuck 3a. That is, the unload tray 32 is located below the workpiece W held by the chuck 3a. Then, the chuck 3a is sent downward to transfer the workpiece W to the unload tray 32.
After the workpiece W is transferred to the unload tray 32, the chuck 3a is sent upward so that the unload tray 32 can move.

FIG. 9 is a plan view showing a state in which the workpiece W is transferred from the unload tray 32. As shown in FIG.
Referring to FIG. 9, the unload tray 32 that has received the workpiece W from the chuck 3 a at the loading position 41 is sent to the reference position 33 where the workpiece W is handed over to the robot 36 .
Then, at the reference position 33, the workpiece W is received by the robot 36.

FIG. 10 is a plan view showing a state in which the workpiece W has been transferred to the unload cassette 38. As shown in FIG.
10, the robot 36 receives the workpieces W from the unload tray 32 sent to the reference position 33, and then stores the workpieces W in the unload cassette 38. Then, when polishing of all the workpieces W to be stored in the unload cassette 38 is completed and the unload cassette 38 is completely stored, the unload cassette 38 is removed from the polishing apparatus 1.

Note that during the polishing process shown in Figure 7, a process of transporting the workpiece W for which polishing has been completed from the chuck 3b to the unload cassette 38 may be carried out as shown in Figures 8 to 10, or a process of transporting the workpiece W from the load cassette 37 to the chuck 3b as shown in Figures 5 to 7.

As shown in Figures 4 and 5, during the process of transporting the workpiece W from the load cassette 37 to the load tray 30 by the robot 36, a process of transferring the workpiece W from the chuck 3 to the reference position 33 by the unload tray 32 may also be carried out as shown in Figures 8 and 9.

Also, when the process of transferring the workpiece W from the reference position 31 to the loading position 41 on the load tray 30 and handing it over to the chuck 3 is performed as shown in Figures 5 and 6, a process of transporting the workpiece W from the unload tray 32 to the unload cassette 38 by a robot 36 as shown in Figure 10 may be performed.
By using the above method, the workpiece W can be transported efficiently, the transport time can be shortened, and productivity can be improved.

Also, as shown in Figure 6, before the process of transferring the workpiece W from the load tray 30 to the chuck 3a, a process of cleaning the holding surface of the chuck 3a using a chuck cleaning device (not shown) may be performed.

As explained above, the polishing device 1 according to this embodiment can prevent the device from becoming too large by using an index 4 that does not require a central rotation axis, and the small index 4 allows for highly accurate and efficient transport of the workpiece W. This results in a compact, high-performance polishing device 1 that can improve productivity for semiconductor wafers and the like.

The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

1 Polishing device 2 Polishing table 3, 3a, 3b Chuck 4 Index 5 Workpiece transport mechanism 9 Polishing cloth 10 Base frame 11 Column 12 Upper plate 13 Support 14 Rotating shaft 15 Chuck motor 16 Pulley 17 Pulley 18 Belt 19 Air cylinder 20 Bearing 21 Inner ring 22 Outer ring 23 Roller 24 Index motor 25 Belt clamp 26 Pulley 27 Belt 28 Lower partition 29 Upper partition 30 Load tray 31 Reference position 32 Unload tray 33 Reference position 34 Rail 36 Robot 37 Load cassette 38 Unload cassette 40 Polishing position 41 Loading position W Workpiece

Claims (7)

a polishing table that rotates and holds a polishing cloth on its upper surface ;
a chuck that adsorbs a workpiece on its lower surface and rotates to bring the lower surface of the workpiece into sliding contact with the upper surface of the polishing cloth;
an index that rotates to transfer the workpiece held by the chuck together with the chuck;
a base table on which the polishing table is disposed;
a column provided on the upper portion of the base table and supporting the index ;
A polishing device characterized in that a support member for rotatably supporting the index is provided on the periphery of the index. The polishing device of claim 1, characterized in that a power transmission member is provided on the periphery of the index, transmitting rotational power from the drive means to the index. The polishing device described in claim 2, characterized in that the power transmission member includes a belt clamp provided on the peripheral edge of the index and a belt whose both ends are fixed to the belt clamp. The polishing device described in claim 2, characterized in that the power transmission member includes a pulley provided on the periphery of the index and having a concave-convex tooth profile formed on the transmission surface, and a belt meshing with the pulley. The polishing device described in claim 2, characterized in that the power transmission member includes a large gear provided coaxially with the index on the periphery of the index, and a small gear meshing with the large gear. A polishing device as described in any one of claims 1 to 5, characterized in that the support member is a bearing having an inner ring fixed to the peripheral portion of the index, an outer ring fixed to the column side, and cylindrical rolling elements arranged between the inner ring and the outer ring so that they are alternately perpendicular to each other . a polishing table that holds a polishing cloth and rotates;
a chuck that adsorbs and rotates a workpiece to bring the workpiece into sliding contact with the polishing cloth;
an index that rotates to transfer the workpiece held by the chuck together with the chuck;
A support member for rotatably supporting the index and a power transmission member for transmitting rotational power from a driving means to the index are provided on the periphery of the index,
A polishing device characterized in that the power transmission member has a large gear provided coaxially with the index on the periphery of the index, and a small gear meshing with the large gear .