Polishing Equipment

Abstract

To provide a polish device which includes a small and highly efficient index mechanism and enables downsizing and improvement of productivity of the device.SOLUTION: A polish device includes: a polishing table 2 which rotates holding a polishing cloth 9; a chuck 3 which rotates suctioning a workpiece W and causes the workpiece W to slidably contact with the polishing cloth 9; and an index 4 which rotates to transfer the workpiece W held by the chuck 3 with the chuck 3. A peripheral edge part of the index 4 is provided with a bearing 20 which rotatably supports the index 4. The structure eliminates the need for providing a support pillar etc. for supporting the index 4 at a center part of the index 4 to enable downsizing of the polish device. Further, a transfer distance of the workpiece W is shortened by downsizing of the index 4 to achieve efficient transfer of the workpiece W by the index 4.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a polishing apparatus for polishing workpieces such as semiconductor wafers, and more particularly to a polishing apparatus equipped with an index mechanism that can be made compact. [Background technology]

[0002] Conventionally, there are polishing apparatuses that perform polishing processes such as chemical mechanical polishing (CMP) on semiconductor wafers, etc. Known polishing apparatuses of this type include those equipped with an index mechanism that transports a workpiece such as a semiconductor wafer to a processing position on a polishing table.

[0003] For example, Patent Document 1 discloses a polishing apparatus having an index head whose center is journaled on a hollow shaft that can rotate forward and backward. A plurality of chuck mechanisms that suction-hold wafers from above are provided below the index head on the same circumference centered on the hollow shaft of the index head. The wafers held by the chuck mechanisms are transported to the position where the polishing process will be performed by the rotation of the index head, and while rotating around the rotation axis of the chuck mechanisms, they are pressed against a rotating polisher below and polished.

[0004] 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 transfer a workpiece held on the upper surface of the substrate holder table. The substrate holder tables then rotate around spindles connected to them as rotation axes, and a rotating polishing pad descends from above the rotating workpiece, rubbing the upper surface of the workpiece with the polishing pad to polish it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-24916 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-221416 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the polishing apparatus equipped with the index mechanism of the above-mentioned prior art has some points that need to be improved in order to improve the productivity of semiconductor wafers and the like and to reduce the size of the apparatus.

[0007] 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 corresponding to the diameter of the support pillar, requiring a large area for the indexing mechanism, resulting in a large polishing apparatus.

[0008] Furthermore, in a configuration in which the center of the index is supported by a support, the distance the workpiece travels when the index is rotated to move it is long. That is, the radius of rotation of the workpiece during movement is large by an amount corresponding to the diameter of the support provided at the center, and the rotation circumference is long. Therefore, it is difficult to reduce the time required to move the workpiece and improve productivity.

[0009] The present invention has been made in consideration of the above circumstances, and its object is to provide a polishing apparatus that is equipped with a small, highly efficient indexing mechanism, thereby enabling the apparatus to be made smaller and its productivity to be improved. [Means for solving the problem]

[0010] The polishing apparatus of the present invention comprises: On the top a polishing table that holds a polishing cloth and rotates; On the underside The workpiece is attracted and rotated. Underside of 5. The polishing cloth Top ofa chuck that slides against the workpiece; and an index that rotates to transport the workpiece held by the chuck together with the chuck. a base table on which the polishing table is disposed, a column disposed on the base table and supporting the index; The index has a support member provided at its periphery for rotatably supporting the index. [Effects of the Invention]

[0011] The polishing apparatus of the present invention comprises a polishing table that rotates while holding an abrasive cloth, a chuck that rotates while adsorbing a workpiece, and an index that rotates to transport the workpiece held by the chuck, and a support member that rotatably supports the index at the periphery of the index. This configuration eliminates the need for a support pillar or the like in the center of the index, allowing the polishing apparatus to be made more compact. Furthermore, the smaller index shortens the distance the workpiece must be transported, enabling more efficient workpiece transport by the index.

[0012] Furthermore, according to the polishing device of the present invention, a power transmission member may be provided on the periphery of the index to transmit rotational power from the drive means to the index. This eliminates the need to provide a rotation shaft or the like in the center of the index to transmit rotational power to the index. This results in a small, highly efficient index mechanism, making it possible to downsize the polishing device and improve productivity.

[0013] 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, and efficiently transmits power from the driving means, allowing for efficient rotation of a small index that does not have a support pillar in the center.

[0014] 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 toothed transmission surface, and a belt meshing with the pulley. This configuration allows for efficient transmission of power from the driving means, enabling efficient rotation of a small index that has no support pillar at its center.

[0015] The power transmission member may have a large gear provided coaxially with the index on the periphery of the index, and a small gear meshing with the large gear. With this configuration, the power from the driving means can be efficiently transmitted by the gear mechanism, and a small index that does not have a support pillar at the center can be efficiently rotated.

[0016] Furthermore, the polishing apparatus of the present invention may include a base table on which the polishing table is disposed, and a column disposed above the base table and supporting the index, wherein the polishing cloth is held on the upper surface of the polishing table, and the workpiece is 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 allows a large-diameter polishing table to be provided that can precisely hold a polishing cloth with a diameter larger than that of the workpiece held in the chuck, while preventing the polishing apparatus from becoming too large. Therefore, the workpiece can be efficiently transported using a small index without a central support, and the workpiece can be polished with a large-diameter polishing cloth with high precision.

[0017] 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, and cylindrical rolling elements arranged between the inner ring and the outer ring so that the rolling elements are alternately perpendicular to each other. This allows the inner ring and the outer ring to be in line contact with the rolling elements, thereby simultaneously supporting complex loads such as radial loads, axial loads, and moments with small elastic displacement, and supporting the index so that it can rotate with high precision. Therefore, without providing a support pillar in the center of the index, a small index can accurately transport workpieces, allowing for highly efficient polishing. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a plan view showing a schematic configuration of a polishing device according to an embodiment of the present invention. [Figure 2] 1 is a side view showing a schematic configuration of a polishing device according to an embodiment of the present invention. [Figure 3] 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 line AA. [Figure 4] 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. [Figure 5] 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. [Figure 6] 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; [Figure 7] 1 is a plan view showing a state during polishing of a polishing device according to an embodiment of the present invention. FIG. [Figure 8] 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. [Figure 9] 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; [Figure 10] 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 INVENTION

[0019] 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, into a highly flat surface.

[0020] The polishing device 1 has a polishing table 2 that holds a polishing 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.

[0021] FIG. 2 is a side view showing a schematic configuration of the polishing apparatus 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 and is mounted on a base frame 10 so as to be horizontally rotatable. The polishing table 2 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).

[0022] The polishing cloth 9 is a cloth member for polishing the workpiece W. As the polishing cloth 9, for example, a foamed polyurethane sheet, a nonwoven fabric made of synthetic fibers, or other felt may be used.

[0023] The chuck 3 is a mechanism for suction-holding and rotating the workpiece W to be polished. The chuck 3 has a substantially circular holding surface for holding 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.

[0024] The holding surface of the chuck 3 that holds the workpiece W is configured to be rotatable around a rotation axis 14 provided 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. That is, the workpiece W rotates horizontally around the rotation axis 14 of the chuck 3.

[0025] The chuck 3 has a smaller diameter than the polishing table 2. In other words, the polishing table 2 can hold with high precision an abrasive cloth 9 having a larger diameter than the workpiece W held by the chuck 3. By providing such a large-diameter polishing table 2, the polishing apparatus 1 can polish the workpiece W with high precision using the large-diameter abrasive cloth 9 while preventing the overall size of the apparatus from increasing by using a small index 4 with no support pillar in the center.

[0026] The power transmission means for transmitting the rotational power of the chuck motor 15 to the chuck 3 is, for example, a V-belt, a 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 wound around the pulley 16 and the pulley 17. The chuck motor 15 may be a direct drive motor or the like that drives the chuck 3 without using a power transmission means.

[0027] 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 provided above the index 4 and feeds the chuck 3 vertically, and in the polishing process, presses the workpiece W held by the chuck 3 against the polishing surface of the polishing cloth 9.

[0028] In the polishing apparatus 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, in 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. Then, the surface to be polished of the workpiece W is pressed against the polishing surface of the polishing cloth 9. As a result, the surface to be polished of the workpiece W is polished.

[0029] The index 4 is an indexing device that rotates to transfer the workpiece W held by the chuck 3 to the polishing position 40. Specifically, the index 4 has a substantially circular shape and is supported by a column 11 provided above the base frame 10 so as to be horizontally rotatable.

[0030] More specifically, above the base frame 10, a column 11 is formed, which has a support 13 standing upright from the base frame 10 and an upper plate 12 supported by the support 13. The index 4 is supported by the upper plate 12 of the column 11 so as to be rotatable.

[0031] The index 4 is provided with two chucks 3, and the index 4 rotates around the central axis of the index 4 while supporting the chucks 3. By rotating the index 4, the workpiece W held by the chucks 3 is sent from the loading position 41 to the polishing position 40, or vice versa.

[0032] Here, we will explain in detail the rotation mechanism of the index 4. 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 by the upper plate 12 via the bearing 20.

[0033] In this way, since the peripheral edge of the index 4 is supported 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 the index 4. 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. Therefore, the productivity of the workpiece W by the polishing device 1 can be increased.

[0034] The column 11 is also provided with an index motor 24, which is a driving means for rotating the index 4 to transport the workpiece W. The rotational power of the index motor 24 is transmitted to the periphery of the index 4.

[0035] More specifically, the index 4 is provided at its periphery with belt clamps 25 for fixing both ends of a belt 27 serving as a power transmission member for transmitting rotational power from the index motor 24 to the index 4 .

[0036] A pulley 26 is fixed to the output shaft of the indexing motor 24. The pulley 26 fixed to the output shaft of the indexing motor 24 and a belt clamp 25 provided on the periphery of the index 4 are connected via a belt 27 so as to be capable of transmitting power.

[0037] 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 rotating shaft or the like in the center of the index 4 to transmit rotational power to the index 4, as described above. This makes it possible to obtain a small, highly efficient index mechanism, thereby making it possible to reduce the size of the polishing device 1 and improve productivity.

[0038] 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 may be, for example, a V-belt, a timing belt, or any other type of belt mechanism.

[0039] For example, the pulley 26, which is a power transmission member that transmits rotational power to the index 4, may be a timing pulley having 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 fixes both ends of the timing belt.

[0040] With this configuration, the power from the index motor 24 can be transmitted efficiently and accurately, and the small index 4, which has no support pillar in the center, can be rotated to an accurate position efficiently and with high precision.

[0041] In addition, a pulley (not shown) that engages 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.

[0042] Furthermore, the power transmission member that transmits the rotational power from the index motor 24 to the index 4 may be a gear mechanism. For example, a large gear (not shown) having teeth formed with a pitch circle coaxial with the index 4 and the 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 so as to transmit power freely.

[0043] The polishing apparatus 1 has a polishing liquid supply device (not shown) that supplies a 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, an alkaline aqueous solution, or an acidic aqueous solution, in which abrasive grains such as silicon oxide (silica), aluminum oxide (alumina), cerium oxide (ceria), or manganese oxide are mixed.

[0044] 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 and sharpens the polishing cloth 9. The dresser is, for example, a diamond dresser with diamond abrasive grains electrodeposited with nickel (Ni).

[0045] The dresser may also be made of, for example, synthetic resin. The synthetic resin material constituting 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.

[0046] The dressing device may also include a high-pressure water generator that supplies high-pressure water, and a high-pressure water spray nozzle that sprays 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. With this configuration, the polishing surface of the polishing cloth 9 or the dressing surface of the dresser can be effectively cleaned, and excellent dressing performance can be achieved.

[0047] The polishing apparatus 1 is provided with a load cassette 37 for supplying the workpiece W to be processed into the apparatus, and an unload cassette 38 for removing the workpiece W that has been polished from the apparatus.

[0048] The load cassette 37 and the unload cassette 38 are cassettes that can accommodate a plurality of workpieces W. The load cassette 37 and the unload cassette 38 are configured to be removable from the polishing apparatus 1.

[0049] The workpiece transport mechanism 5 is a mechanism that 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 accommodated in the load cassette 37 to the chuck 3, and transports the workpiece W after polishing from the chuck 3 to the unload cassette 38.

[0050] The work transport mechanism 5 has a robot 36 that transports the work W to the load cassette 37 and the unload cassette 38, a load tray 30 that sends the work W received from the robot 36 to the chuck 3, and an unload tray 32 that receives the work W from the chuck 3 and hands it over to the robot 36.

[0051] 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.

[0052] 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 is transported from the robot 36, and sends and delivers the workpiece W to the chuck 3.

[0053] The load tray 30 is supported by rails 34 that extend horizontally and are provided on the upper part of the base frame 10, and moves along the rails 34. Specifically, the load tray 30 is fed by a drive device (not shown) and can move back and forth from a reference position 31 where it receives the workpiece W from the robot 36 to a loading position 41 where it hands over the workpiece W to the chuck 3.

[0054] The unload tray 32 is a tray for transferring the workpiece W from the chuck 3 to the robot 36. More specifically, the unload tray 32 receives the polished workpiece W from the chuck 3 at the loading position 41, and then transfers the workpiece W to the reference position 33 to transfer it to the robot 36.

[0055] The unload tray 32 is supported by rails 34 and moves along the rails 34. Specifically, the unload tray 32 is fed by a drive device (not shown) and can move back and forth from a reference position 33 where the workpiece W is handed over to the robot 36 to a loading position 41 where the workpiece W is received from the chuck 3.

[0056] In this way, the load tray 30 and the unload tray 32 are provided at symmetrical positions at substantially the same distance from the chuck 3 so that they can reciprocate along the rails 34 .

[0057] 1, the reference position 31 at which the load tray 30 receives the workpiece W from the robot 36 is located to the left of the loading position 41 located approximately in the center of the polishing apparatus 1, i.e., on the left side of the polishing apparatus 1. On the other hand, the reference position 33 at which 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. The arrangement of the load tray 30 and unload tray 32 may be reversed from the above.

[0058] A lower partition wall 28 and an upper partition wall 29 are provided between the load tray 30 and the 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 the unload tray 32 during the polishing process.

[0059] Specifically, the lower partition 28 is fixed to the upper part 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 lower part 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 and the like in a configuration in which the workpiece W is transported by the rotation of the index 4.

[0060] The polishing apparatus 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 member that removes polishing debris and the like that has adhered to the chuck 3 during the polishing process before the chuck 3 holds the next workpiece W to be processed, and is provided, for example, on the upper part 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.

[0061] The chuck cleaning device may be provided with a high-pressure water spraying means (not shown) that sprays high-pressure water onto the holding surface of the chuck 3 in order 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.

[0062] FIG. 3(A) is a cross-sectional view showing an outline of a bearing 20 that supports the index 4, and FIG. 3(B) is a cross-sectional view taken along line AA shown in FIG. 3(A). 3(A) and 3(B), the bearing 20 serving as a support member for supporting the index 4 may be, for example, a cross roller bearing. In detail, 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 between the inner ring 21 and the outer ring 22 so that they are alternately perpendicular to each other.

[0063] By adopting 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 be rotated with high precision.

[0064] That is, due to the line contact between the inner ring 21 and outer ring 22 and the rollers 23, the bearing 20, despite its small size, can simultaneously withstand complex loads such as radial load, axial load, and moment acting on the index 4 during the transfer process and polishing process of the workpiece W (see Figure 2), and with small elastic displacement.

[0065] As a result, the column 11 can support the index 4 via the bearing 20 so that it can rotate with high precision. Therefore, without providing a support pillar at the center of the index 4, the workpiece W can be transported accurately and stably with the small index 4, allowing for highly efficient and highly precise polishing.

[0066] 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 multiple 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.

[0067] 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.

[0068] 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.

[0069] 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, which is located at the polishing position 40 on the polishing table, holds another workpiece W (not shown), and the workpiece W is being polished.

[0070] The workpiece W sent to the loading position 41 is delivered to the upper chuck 3a and held by suction. That is, the chuck 3a is sent by the air cylinder 19 (see FIG. 2) so as to come into contact with the workpiece W below the holding surface, and adsorbs the workpiece W. Then, the chuck 3a holding the workpiece W is sent 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.

[0071] FIG. 7 is a plan view showing the state of the polishing apparatus 1 during polishing. As shown in Fig. 6, after the workpiece W is transferred to the chuck 3a at the loading position 41, the index 4 rotates 180 degrees with its peripheral edge supported by the bearings 20 as shown in Fig. 7. This causes the chuck 3a and the workpiece W held by the chuck 3a to be 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.

[0072] Next, the chuck 3a is sent downward, and the lower surface of the workpiece W, which is the surface to be polished, comes into sliding contact with 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.

[0073] Specifically, the workpiece W is pressed by the air cylinder 19 (see FIG. 2) via the chuck 3a, and the chuck 3a is rotated by the chuck motor 15 (see FIG. 2), which is then driven by a driving means (not shown) to rotate the polishing table 2. The surface to be polished of the workpiece W is polished by the relative movement between the workpiece W and the polishing cloth 9.

[0074] When the polishing process is completed, the chuck 3a is sent upward while 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.

[0075] FIG. 8 is a plan view showing a state in which the workpiece W is received by the unload tray 32. 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.

[0076] Specifically, the index 4 is driven by the index motor 24 and rotates 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.

[0077] 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.

[0078] 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 3a at the loading position 41 is sent to the reference position 33 where the workpiece W is handed over to the robot . Then, at the reference position 33, the workpiece W is received by the robot 36.

[0079] 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.

[0080] During the polishing process shown in FIG. 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 FIGS. 8 to 10, or a process of transporting the workpiece W from the load cassette 37 to the chuck 3b as shown in FIGS. 5 to 7.

[0081] As shown in Figures 4 and 5, in 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 be carried out as shown in Figures 8 and 9.

[0082] 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 using 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.

[0083] Furthermore, as shown in FIG. 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 with a chuck cleaning device (not shown) may be performed.

[0084] As explained above, the polishing apparatus 1 according to this embodiment can prevent the apparatus from becoming large by using the index 4 that does not require a rotation axis in the center, and can transport the workpiece W with high precision and efficiency using the small index 4. Therefore, a small, high-performance polishing apparatus 1 can be obtained, and productivity of semiconductor wafers and the like can be improved.

[0085] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0086] 1 Polishing device 2 Polishing table 3, 3a, 3b chuck 4 Index 5 Work transport mechanism 9 Polishing cloth 10 Base Frame 11 Column 12 Upper plate 13 Posts 14 Rotation axis 15 Chuck motor 16 pulleys 17 Pulley 18 Belt 19 Air cylinder 20 Bearings 21 Inner Circle 22 outer ring Around 23 24 Index motor 25 Belt clamp 26 Pulley 27 Belt 28 Lower Bulkhead 29 Upper bulkhead 30 Load Tray 31 Reference position 32 Unload tray 33 Reference position 34 Rail 36 Robot 37 Road Cassette 38 Unloading cassette 40 Polishing position 41 Loading Position double work

Claims

1. A polishing table that rotates while holding 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.

2. 2. The polishing device according to claim 1, wherein a power transmission member for transmitting rotational power from a driving means to said index is provided on a peripheral edge of said index.

3. 3. The polishing device according to claim 2, wherein the power transmission member comprises a belt clamp provided on the periphery of the index, and a belt having both ends fixed to the belt clamp.

4. 3. The polishing device according to claim 2, wherein the power transmission member comprises a pulley provided on the periphery of the index and having a concave-convex tooth profile formed on a transmission surface thereof, and a belt meshing with the pulley.

5. 3. The polishing device according to claim 2, wherein the power transmission member comprises a large gear provided coaxially with the index on the periphery of the index, and a small gear meshing with the large gear.

6. 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.

7. 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.

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