Workpiece chuck device and workpiece processing method

Abstract

To provide a workpiece chuck device capable of preventing an electrolyte and grinding dust from entering a space between a suction part and a workpiece during processing of the workpiece.SOLUTION: A workpiece chuck device includes a vacuum chuck 2 which is detachably coupled to a spindle 1 and suctions a wafer 5. The vacuum chuck 2 has a conductive porous 6 for applying voltage to the wafer 5 through the spindle 1 and is connected at the grindstone 9 side to a ground. Further, in the vacuum chuck 2, a plurality of air purge ports 19 are provided at the outer periphery side of the suctioned wafer 5. Positive pressure air is supplied from a positive pressure air coupler 22 through the spindle 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a chuck device that adsorbs a workpiece while applying a voltage to the workpiece, and a method for processing the workpiece.

Background Art

[0002] ECMG / P (Electro Chemical Mechanical Grinding / Polishing) processing is a method in which, as shown in FIG. 21, a semiconductor wafer such as silicon as a workpiece is adsorbed by a vacuum chuck having a built-in electrode, and the surface of the wafer is anodized to soften the processing surface, thereby performing high-speed and high-flatness mirror surface processing. For the wafer chucked by the vacuum chuck, electricity is supplied from the copper ring on the outer periphery to the chuck electrode to perform grinding and polishing. Patent Document 1 is a publication that discloses an example of a vacuum chuck device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] During the processing of the wafer, if the electrolytic solution scatters and the electrolytic solution enters the space between the copper ring and the SUS interface constituting the vacuum chuck, or enters the inside of the porous chuck from the gap between the adsorption surface and the wafer, as shown in FIG. 22, the porous chuck and the SUS interface will conduct electricity. Then, the current required for processing cannot be supplied to the wafer, which will affect the processing accuracy and processing time of the wafer. In addition, if grinding debris enters and accumulates inside the porous chuck, the grinding debris will be sandwiched between the adsorption surface and the wafer during processing, resulting in deterioration of the flatness of the wafer or causing cracks.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a work chuck device and a work processing method capable of preventing electrolytic solution and grinding chips from entering between the suction portion and the work during the processing of the work.

Means for Solving the Problems

[0006] The work chuck device according to claim 1 includes a suction portion (2) that is detachably connected to a spindle (1) to suck a work (5) and rotate and process the work. The suction portion has a positive or negative electrode (6) for applying a voltage to the work via the spindle, and the negative or positive electrode is provided on the tool side or the like for processing the work. Further, in the suction portion, positive pressure air is supplied from a positive pressure air supply portion (22) via the spindle to a plurality of positive pressure air supply ports (19) provided on the outer peripheral side of the work.

[0007] With this configuration, when the suction portion that has sucked the work is coupled to the spindle and the work is rotationally processed while applying a voltage to the work, the electrolytic solution and grinding chips are removed from the outer peripheral side of the work by the positive pressure air. Therefore, it is possible to prevent them from entering between the suction portion and the work, and it becomes possible to improve the processing accuracy of the work.

[0008] According to the work chuck device described in claim 2, a groove portion (50) is formed on the surface side of the suction portion that sucks the work, and the positive pressure air supply port is formed in the groove portion. With this configuration, the positive pressure air can be supplied along the groove portion to the outer peripheral side of the work.

[0009] According to the work chuck device described in claim 3, an electrolytic solution separation portion (12) for separating and storing the electrolytic solution used for processing the work is provided in the path through which the negative pressure air flows. That is, since the electrolytic solution is also sucked and flows in the path through which the negative pressure air flows, the electrolytic solution sucked by the electrolytic solution separation portion can be separated and stored.

[0010] According to the work chuck device described in claim 4, the electrolytic solution separation unit can drain the stored electrolytic solution to the outside with the drain port through which the negative pressure air flows closed by the drain mechanism (32).

[0011] According to the work chuck device described in claim 5, even when the suction unit is separated from the spindle, the auxiliary negative pressure air supply unit (24) supplies negative pressure air for sucking the workpiece. Thereby, even in the processes before and after processing, the workpiece can be kept in a state of being sucked by the suction unit.

Brief Description of the Drawings

[0012]

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Mode for Carrying Out the Invention

[0013] Hereinafter, an embodiment will be described. As shown in FIG. 1, the ECMP processing system of this embodiment includes a vacuum chuck 2 which is a detachable suction part with respect to the spindle 1. As shown in FIG. 3, the vacuum chuck 2 is configured by coupling a shank 3 and an interface 4 which are generally disk-shaped, and the interface 4 is larger in diameter than the shank 3. The vacuum chuck 2 sucks the semiconductor wafer 5 such as silicon, which is a workpiece, by creating a vacuum state between the surface of the semiconductor wafer 5 and the suction surface by the vacuum pressure air supplied through the spindle 1. Hereinafter, the semiconductor wafer will be simply referred to as "wafer". The vacuum pressure air corresponds to negative pressure air.

[0014] On the above adsorption surface, a conductive porous body 6, which is an anode electrode and is omitted in FIG. 1 and shown in FIG. 2, is arranged. The conductive porous body 6 is a porous body having conductivity and is connected to a power supply device 8 via a power supply part 7 inside the spindle 1. The cathode is on the side of the grindstone 9, which is a tool for rotary machining, and the grindstone 9 side is connected to the ground. The spindle 1 moves up and down, and as the grindstone 9 rotates, the lower surface side of the wafer 5 in the figure in the state of being adsorbed by the vacuum chuck 2 is polished. When the polishing is performed, an electrolytic solution is supplied. A plurality of adsorption ports 10 for adsorbing the wafer 5 by vacuum pressure air are in contact with the conductive porous body 6 and are formed on the interface 4. The adsorption ports 10 are connected to a vacuum air path 11a formed inside the vacuum chuck 2.

[0015] FIG. 13 shows a configuration close to an actual ECMP processing system. A grindstone 9 (not shown in the figure) is also arranged in the processing machine main body 41 where the spindle 1 is arranged. Below in the figure, there are a wafer loading / unloading part 42 and a chuck cleaning / drying part 43. In the wafer loading / unloading part 42, the vacuum chuck 2 in the state of adsorbing the wafer 5 by the vacuum auxiliary coupler 24, which is an auxiliary negative pressure air supply part, is loaded and unloaded. In the chuck cleaning / drying part 43, the vacuum chuck 2 after processing is cleaned and dried.

[0016] The loaded vacuum chuck 2 and wafer 5 are loaded into the ATC (Automatic Tool Changer) part 45 via the chuck loader part 44. In the ATC part 45, the arm rotates to exchange the vacuum chuck 2 and wafer 5 before and after processing. In the process flow shown in FIG. 14, when the processing of the wafer 5 is completed (S1), the chuck is exchanged by the ATC part 45 (S2). Then, the chuck loader part 44 retreats (S3) and the processed wafer 5 is taken out (S4). Subsequently, after the chuck surface after processing is cleaned and dried (S5), an unprocessed wafer 5 is attached (S6) and the chuck loader part 44 advances (S7). Then, it returns to step S1.

[0017] FIG. 15 shows the details of the operation of replacing the vacuum chuck 2 before and after processing, but only the parts related to the gist of this embodiment will be described. The suction of the wafer 5 is performed by the vacuum air supplied through the spindle 1 from "cover open" in the processing machine until the start of chuck replacement in the ATC unit 45. When the chuck replacement is started, the suction of the wafer 5 is performed by the vacuum air supplied from the ATC unit 45 as described later. When the chuck replacement is completed, the vacuum air is supplied through the spindle 1 in parallel.

[0018] Regarding FIGS. 16 to 20, the general outlines will also be described. FIG. 16 shows a superposition of the case where the arm of the ATC unit 45 is at the retracted end and the case where it has moved to the advanced end and rotated 90 degrees. FIG. 17 shows the state where the vacuum auxiliary coupler 24 of the vacuum chuck 2 is connected to the vacuum air supply path on the ATC unit 45 side. FIG. 18 shows the state where the spindle 1 is at the standby position and the vacuum chuck 2 is located below the spindle 1. FIG. 19 shows the state where the spindle 1 has moved to the attachment / detachment position and joined the vacuum chuck 2. FIG. 20 shows the state where the spindle 1 joined with the vacuum chuck 2 has returned to the standby position.

[0019] Referring to FIG. 1 again, a separator 12, which is an electrolytic solution separation part, is attached to the outer peripheral part of the interface 4. The vacuum air path 11a is connected to the vacuum air path 11b via the inside of the separator 12. The electrolytic solution sucked from the suction port 10 is separated and stored in the separator 12. The vacuum air path 11b is drawn out to the outside via the inside of the spindle 1 and is connected to the vacuum pump 14 via the switching valve 13. As will be described later, air for vacuum destruction is supplied to the switching valve 13 by switching.

[0020] The electrolytic solution stored in the separator 12 is discharged to the outside when the seal member 15 below moves, and is stored in the tank 17 through the drain channel 16. The electrolytic solution stored in the tank 17 is pumped out by the pump 18 and supplied to the polishing site by the grindstone 9. The electrolytic solution is used cyclically as described above. The detailed configuration of the separator 12 will be described later. As shown in FIGS. 3 and 4, the separator 12 and the tank 17 are arranged at two locations of the interface 4, but only one is shown in FIG. 1.

[0021] At the interface 4, a groove portion 50 is formed in a circumferential shape on the outer peripheral portion where the wafer 5 is adsorbed, and eight air purge ports 19 are formed inside the groove portion 50. These air purge ports 19 are connected to the positive pressure air path 20, and the positive pressure air supplied from the outside of the spindle 1 is discharged from the air purge ports 19. By this positive pressure air, grinding chips and electrolytic solution during polishing are removed.

[0022] As shown in FIGS. 3 and 4, three vacuum air couplers 21, a positive pressure air coupler 22, and an electrode 23 are arranged on the upper surface side of the shank 3 at the portion coupled to the spindle 1. When the vacuum chuck 2 is coupled to the spindle 1, these are respectively connected to the positive pressure air path 20, the vacuum air path 11b, and the power supply unit 7 on the spindle 1 side, so that positive pressure air, vacuum air, and voltage are respectively supplied through the spindle 1.

[0023] Also, as shown in FIG. 2, a vacuum assist coupler 24 is provided on the outer peripheral portion of the interface 4. The vacuum assist coupler 24 is connected to the vacuum path 11a, and by supplying vacuum air from another vacuum air supply source on the ATC side, the state of adsorbing the wafer 5 can be maintained even when the vacuum chuck 2 is separated from the spindle 1.

[0024] As shown in Fig. 5, the power supply unit 7 mainly consists of an electrode 23, a probe 26, an electrode 27, and a copper plate 28. In Fig. 6, which is shown at an angle to Fig. 5, the copper plate 28 is connected to the conductive porous body 6 via a probe 29 that extends further downward. An insulating material 30 is disposed above the copper plate 28 and around the periphery of the probe 29 and the like.

[0025] As shown in Fig. 7, during the processing of the wafer 5, the wafer 5 is adsorbed by the vacuum chuck 2 by the vacuum air supplied from both the vacuum air coupler 21 and the vacuum assist coupler 24. At the same time, positive pressure air is supplied from the air purge port 19 to the outer peripheral portion of the wafer 5 to exclude the grinding debris and electrolyte solution of the wafer 5 from entering between the wafer 5 and the conductive porous body 6. At this time, the drain port 31 of the separator 12 is sealed by a seal member 15 that constitutes the drain valve 32, and the electrolyte solution sucked into the vacuum path 11a is stored inside the separator 12.

[0026] As shown in Fig. 8, when the processing of the wafer 5 is completed, the supply of positive pressure air is stopped, and the vacuum air is supplied only from the vacuum assist coupler 24. At this time, when the pusher 33 is displaced upward in the figure, the space between the vacuum paths 11a and 11b is blocked inside the separator 12, and the seal member 15 is also displaced upward to open the drain port 31. Thereby, the electrolyte solution stored in the separator 12 is drained.

[0027] Figs. 9 and 10 show a more detailed configuration of the drain valve 32, which is a drain mechanism. The drain valve 32 includes a spring 34, a seal member 35, vacuum break paths 36a and 36b, and the like. With the vacuum chuck 2 mounted on the ATC unit 45, the lower end surface of the seal member 15 of the drain valve 32 abuts against the upper end surface of the pusher 33. At this time, it is in the original position shown at the right end of Fig. 10, the space between the vacuum paths 11a and 11b is in communication, and the drain port 31 is closed by the seal member 15.

[0028] When the pusher cylinder 37 on the ATC unit 45 side is displaced downward, the pusher 33 is displaced upward by air pressure. Then, the spring 34 is bent and the space between the vacuum paths 11a and 11b is blocked by the seal member 35. At the same time, the vacuum break paths 36a and 36b allow air to flow through, and the vacuum state inside the separator 12 is destroyed. When the pusher 33 is further displaced upward and the drain port 31 opens, the electrolyte stored by the positive-pressure air supplied as the air pressure to the separator 12 is drained.

[0029] As shown in FIG. 11, when cleaning the vacuum chuck 2 after the processing of the wafer 5 is completed, the upper and lower loaders 46 of the chuck cleaning and drying unit 43 are connected to the vacuum chuck 2. At this time, the vacuum air coupler 11 of the vacuum chuck 2 is connected to the cleaning and drying coupler 47 of the upper and lower loader 46. As shown in FIG. 12, the cleaning and drying coupler 47 is selectively supplied with cleaning liquid and clean air for drying via a switching valve 48. By supplying the cleaning liquid, the conductive porous body 6 of the vacuum chuck 2 is mainly cleaned, and by supplying clean air, the cleaned conductive porous body 6 is dried.

[0030] As described above, according to the present embodiment, a vacuum chuck 2 is provided that is detachably connected to the spindle 1 and adsorbs the wafer 5. The vacuum chuck 2 has a conductive porous body 6 for applying a voltage to the wafer 5 via the spindle 1, and the grinding wheel 9 side is connected to the ground. Further, in the vacuum chuck 2, a plurality of air purge ports 19 are provided on the outer peripheral side of the adsorbed wafer 5, and positive-pressure air is supplied from the positive-pressure air coupler 22 via the spindle 1.

[0031] With such a configuration, when the vacuum chuck 2 adsorbing the wafer 5 is coupled to the spindle 1 and rotational machining is performed with the grinding wheel 9 while applying a voltage to the wafer 5, the electrolytic solution and grinding chips are removed from the outer peripheral side of the wafer 5 by positive-pressure air. Therefore, it is possible to prevent them from entering between the vacuum chuck 2 and the wafer 5, and it becomes possible to improve the machining accuracy of the wafer 5. And since the groove portion 50 is formed on the surface side where the vacuum chuck 2 adsorbs the wafer 5, and a plurality of air purge ports 19 are formed inside the groove portion 50, positive-pressure air can be evenly supplied to the outer peripheral portion of the wafer 5 adsorbed along the groove portion 50.

[0032] Also, a separator 12 for separating and storing the electrolytic solution used for machining the wafer 5 is provided in the path 11 through which negative-pressure air flows. That is, since the electrolytic solution is also sucked and circulated in the path 11a through which negative-pressure air flows, the electrolytic solution sucked by the separator 12 can be separated and stored. Further, the separator 12 can drain the stored electrolytic solution to the tank 17 with the drain valve 32 closing the circulation port through which negative-pressure air flows.

[0033] Furthermore, even when the vacuum chuck 2 is separated from the spindle 1, negative-pressure air for adsorbing the wafer 5 is supplied from the vacuum assist coupler 24. Thereby, also in the processes before and after machining, the wafer 5 can be kept in a state of being adsorbed by the vacuum chuck 2.

[0034] (Other Embodiments) The number of the air purge ports 19 may be appropriately changed according to individual designs. The groove portion 50 may be provided as needed. The vacuum assist coupler 24 may also be provided as needed. The workpiece is not limited to a semiconductor wafer, and any object that can be rotationally machined while applying a voltage may be used.

[0035] The cathode electrode may be arranged on the adsorption part side. The negative-pressure air may generate a negative pressure sufficient to adsorb the workpiece. Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to such embodiments or structures. The present disclosure also encompasses various modifications and variations within the equivalent scope. In addition, various combinations and forms, and further other combinations and forms including only one element, more than one element, or less than one element thereof, are also within the scope and spirit of the present disclosure.

Explanation of Reference Numerals

[0036] In the drawings, 1 is a spindle, 2 is a vacuum chuck, 5 is a semiconductor wafer, 6 is a conductive porous body, 9 is a grindstone, 10 is a suction port, 11 is a vacuum air path, 12 is a separator, 15 is a seal member, 16 is a drain port, 19 is an air purge port, 20 is a positive pressure air path, 21 is a vacuum air coupler, 22 is a positive pressure air coupler, 24 is a vacuum auxiliary coupler, 32 is a drain valve, and 50 is a groove portion.

Claims

1. A work chuck device that is detachably connected to a spindle (1) and has a suction part (2) for sucking a work (5), and is for rotary machining of the work, wherein the suction part includes, an electrode (6) for positive or negative electrode for applying a voltage to the work via the spindle, a negative pressure air supply part (21) for supplying negative pressure air via the spindle, a suction port (10) for sucking the work by the negative pressure air, a positive pressure air supply part (22) for supplying positive pressure air via the spindle, and a plurality of positive pressure air supply ports (19) provided on the outer peripheral side of the adsorbed work for supplying the positive pressure air to the outer peripheral side, the work chuck device comprising these.

2. The suction part includes a groove part (50) formed on the surface side for sucking the work, and the positive pressure air supply port is formed in the groove part. The work chuck device according to Claim 1.

3. The work chuck device according to Claim 1, wherein an electrolytic solution separation part (12) for separating and storing the electrolytic solution used for machining the work is provided in a path (11) through which the negative pressure air flows.

4. The work chuck device according to Claim 3, wherein the electrolytic solution separation part includes a drainage mechanism (32) for draining the stored electrolytic solution to the outside in a state where a flow port through which the negative pressure air flows is closed.

5. The work chuck device according to Claim 1, further comprising an auxiliary negative pressure air supply part (24) for supplying negative pressure air for sucking the work when the suction part is separated from the spindle.

6. The work chuck device according to Claim 1, wherein a cleaning liquid for cleaning the suction part is supplied via the negative pressure air supply part.

7. The work chuck device according to Claim 6, wherein drying air for drying the cleaned work is supplied via the negative pressure air supply part.

8. A method of sucking a work by a detachably connected suction part and performing rotary machining while applying a voltage to the work, wherein the work is sucked by supplying negative pressure air via the spindle, and the work is machined while supplying positive pressure air via the spindle to a plurality of locations on the outer peripheral side of the adsorbed work. The work machining method.

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