JP7668151B2 - Polishing Equipment - Google Patents

Description

The present invention relates to a polishing device for polishing plate-shaped workpieces such as silicon wafers.

Conventionally, polishing devices are known that perform CMP (Chemical Mechanical Polishing) of semiconductor wafers and the like. One type of polishing device known in the art is one that presses a horizontally rotating workpiece above against the top surface of a polishing cloth that rotates horizontally below, polishing the workpiece while supplying a polishing liquid.

For example, Patent Document 1 discloses a polishing apparatus for polishing substrates such as wafers, which includes a top ring that holds and rotates the substrate, a polishing table that supports a polishing pad, and a polishing liquid supply mechanism that supplies a polishing liquid to the polishing pad.

In the polishing apparatus disclosed in the document, the top ring that supports the substrate is connected to a top ring shaft, and this top ring shaft is provided so as to be movable up and down relative to the top ring head. The top ring head is cantilevered by a top ring head shaft that is rotatably supported by a frame.

For example, Patent Document 2 discloses a workpiece polishing device that includes a base plate with an abrasive cloth attached to its upper surface that rotates in a horizontal plane, and a top ring that is arranged above the base plate so as to be movable up and down and rotatable in the horizontal plane, sandwiching a carrier plate with a workpiece held on its underside between the base plate and the top ring, and pressing the workpiece against the base plate surface.

In the workpiece polishing device disclosed in the document, the top ring has a rotating shaft erected at its upper end, and this rotating shaft is rotatably supported within a cylinder that passes through the upper platen of the device body and moves up and down. The upper end of this cylinder is fixed to a frame, and when this frame is moved up and down by a cylinder device, the top ring moves up and down together with the frame. Furthermore, one end of the frame is guided in its up and down movement by a guide rod.

JP 2014-4675 A JP 2014-647 A

However, the polishing apparatus of the prior art has some points that need to be improved in order to realize polishing with higher precision.
Specifically, in a configuration in which a top ring supporting a workpiece is cantilevered by a top ring head shaft, as in the conventional technology disclosed in Patent Document 1, there was a problem in that the pressing force on the workpiece would cause the top ring shaft and the workpiece supported by it to tilt slightly, making it difficult to perform high-precision machining.

The document discloses a configuration in which a local load applying mechanism is provided to apply a local load to the retaining ring that holds the workpiece, thereby controlling the inclination of the retaining ring. However, a configuration in which such a local load applying mechanism is provided is not easy to control, and it is necessary to provide a highly accurate control device to control the inclination of the retaining ring. As it is necessary to provide a local load applying mechanism with a complex configuration and its control device, improvements are also required from the perspective of the productivity of the polishing device.

Even in a configuration in which one end of a frame that moves up and down together with the top ring is guided by a guide rod, as in the conventional technology disclosed in Patent Document 2, there is a risk that the top ring may tilt slightly.

In recent years in particular, there has been a demand for workpieces such as silicon wafers to be made even larger, thinner, and flatter with greater precision. To meet this demand, grinding machines are required to have highly rigid workpiece holding mechanisms with minimal tilt. However, with grinding machines using conventional technology, it has been difficult to provide highly rigid workpiece support that reduces tilt.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a polishing device that has a highly rigid workpiece holding mechanism that reduces the inclination of the workpiece and is capable of precisely polishing plate-shaped workpieces.

The polishing apparatus of the present invention is a polishing apparatus that polishes a horizontally rotating plate-shaped workpiece by pressing the workpiece against the upper surface of a horizontally rotating polishing cloth, and includes a table that rotates horizontally while holding the polishing cloth on its upper surface, a chuck that is provided above the table and rotates horizontally while holding the workpiece, a chuck support portion that supports the chuck so that it can rotate horizontally, a plurality of guide mechanisms that are arranged opposite each other via the chuck support portion and support the chuck support portion so that it can move vertically, and a feed mechanism that feeds the chuck support portion in the vertical direction , wherein at least one of the guide mechanisms is provided with a pair of upper and lower guides that support the chuck support portion, and the feed mechanism is provided above the chuck support portion so as to transmit power for feeding the chuck support portion in the vertical direction to an upper portion of the chuck support portion that is concentric with the rotation axis of the chuck .

The polishing device of the present invention has a table that holds a polishing cloth on its upper surface and rotates horizontally, a chuck that is arranged above the table and holds a workpiece and rotates horizontally, and a chuck support that supports the chuck so that it can rotate horizontally. The polishing device is equipped with multiple guide mechanisms that are arranged opposite each other via the chuck support and support the chuck support so that it can move up and down. With this configuration, the guide mechanisms can suppress the inclination of the chuck support. Therefore, the inclination of the workpiece can be suppressed and high-precision polishing can be performed.

At least one guide mechanism is provided with a pair of upper and lower guides that support the chuck support part. This allows the upper guide at the top of the guide mechanism to suppress horizontal movement of the upper part of the chuck support part, and the lower guide at the bottom of the guide mechanism to suppress horizontal movement of the lower part of the chuck support part. This allows the chuck support part to be supported appropriately so that it does not tilt even when a large force is applied.

Furthermore, according to the polishing device of the present invention, the guide may have a rail extending in the vertical direction and a block supported on the rail so as to be movable relative to the rail. This reduces frictional resistance between the guide and the chuck support part when the chuck and the chuck support part move in the vertical direction, and can effectively suppress tilting of the chuck and the chuck support part. This allows efficient and highly accurate polishing to be achieved.

In addition, according to the polishing device of the present invention, the block may be fixed to the chuck support portion. That is, the block may be fixed to the chuck support portion, and a rail for guiding the movement of the block may be fixed to the column via a guide stand or the like. With this configuration, tilting of the chuck can be suitably suppressed, and the height dimension of the component that supports the chuck and can move up and down can be reduced, enabling a suitable feed operation.

In addition, according to the polishing device of the present invention, the block may be provided with a rolling element that rolls in contact with the rail. This allows for suitable polishing with small vertical feed resistance and small inclination of the workpiece.

Furthermore, according to the polishing device of the present invention, the guide mechanism may be formed in four pieces. That is, the guide mechanism is formed on four shafts extending in the vertical direction approximately parallel to the rotation axis of the chuck, and each guide mechanism is formed with a pair of upper and lower guides. With such a configuration, it is possible to perform precise polishing processing with minimal tilt of the workpiece.

1 is a front view showing a schematic configuration of a polishing apparatus according to an embodiment of the present invention; 1 is a plan view showing a schematic configuration of a polishing apparatus according to an embodiment of the present invention. 2 is a perspective view showing a guide of a polishing apparatus according to an embodiment of the present invention. FIG. 13 is a front view showing a schematic configuration of a polishing apparatus according to another embodiment of the present invention. FIG. 13 is a plan view showing a schematic configuration of a polishing apparatus according to another embodiment of the present invention. FIG. 13 is a perspective view showing a spindle case of a polishing apparatus according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A polishing apparatus according to an embodiment of the present invention will now be described in detail with reference to the drawings.
FIG. 1 is a front view showing a schematic configuration of a polishing apparatus 1 according to an embodiment of the present invention.
1, a polishing apparatus 1 is an apparatus for polishing a plate-shaped workpiece W such as a semiconductor wafer. Specifically, the polishing apparatus 1 is an apparatus for performing a polishing process such as a CMP process on the workpiece W such as a semiconductor wafer.

The polishing device 1 has a table 2 that holds a polishing cloth 5 on its upper surface and rotates horizontally, a chuck 3 that is provided above the table 2 and rotates horizontally while holding a workpiece W, a chuck support 14 that supports the chuck 3 so that it can rotate horizontally, and a number of guide mechanisms 20 that support the chuck support 14 so that it can move vertically.

The table 2 holds the polishing cloth 5 that slides against the workpiece W to polish the workpiece W. More specifically, the polishing cloth 5 is held on the upper surface of the table 2. The table 2 is driven by a driving device such as a motor (not shown) and rotates approximately horizontally together with the polishing cloth 5.

The chuck 3 is used to suction and hold the plate-shaped workpiece W to be polished. The chuck 3 may be provided with an air bag (not shown) or the like for pressing the workpiece W against the polishing cloth 5 during polishing. The chuck 3 is held by a column 4 so that it can rotate horizontally and is provided above the table 2.

Specifically, the chuck 3 is supported by the chuck support 14 so that it can rotate horizontally. The chuck support 14 is supported by the guide stand 13 of the column 4 via the guide mechanism 20 so that it can move vertically.

The guide stand 13 is fixed to and supported by an upper plate 12 of the column 4 below it, and the upper plate 12 is fixed to the top of the support pillar 11 of the column 4.
A motor (not shown) or the like serving as a drive source for rotating the chuck 3 may be disposed inside a spindle case 15 constituting the chuck support portion 14 .

The guide mechanism 20 is a mechanism that supports the chuck support part 14 so that it can move up and down freely. The guide mechanism 20 guides the movement of the chuck support part 14 in the up and down direction, and prevents the chuck support part 14 from moving in the horizontal direction and tilting. In other words, the guide mechanism 20 can suppress the tilt of the chuck support part 14, and the tilt of the workpiece W can be suppressed to perform high-precision polishing processing.

Multiple guide mechanisms 20 are provided and are arranged opposite each other via the chuck support portion 14. Specifically, the guide mechanisms 20 are arranged opposite each other on both horizontal sides of the chuck support portion 14, i.e., on both the left and right sides of the chuck support portion 14, sandwiching the chuck support portion 14.

The guide mechanism 20 is provided with a pair of upper and lower guides 21. That is, the guide mechanism 20 is provided with an upper guide 22 at its upper portion and a lower guide 23 at its lower portion.

The upper guide 22 and the lower guide 23 are members that suppress horizontal movement of the chuck support part 14, support the chuck support part 14 so that it can move up and down freely, and guide the movement of the chuck support part 14 in the up and down direction.

The upper guide 22 at the top of the guide mechanism 20 prevents the upper part of the chuck support part 14 from moving horizontally, and the lower guide 23 at the bottom of the guide mechanism 20 prevents the lower part of the chuck support part 14 from moving horizontally. Therefore, the chuck support part 14 can be supported appropriately so that it does not tilt even when a large force is applied.

Although not shown in the figure, the polishing apparatus 1 is also equipped with a polishing liquid supplying device that supplies a polishing liquid, i.e., slurry, to the polishing cloth 5. When polishing the workpiece W, the polishing liquid supplying device supplies a polishing liquid containing abrasive grains to the surface of the polishing cloth 5. This allows the workpiece W to be processed using the free abrasive method.

The polishing device 1 also has a feed mechanism 30 that feeds the chuck 3 in the vertical direction. The feed mechanism 30 has, for example, a motor 31 as a vertical feed drive means, a ball screw nut 33 that rotates by the power of the motor 31, and a ball screw 32 that feeds the chuck support part 14 in the vertical direction by the rotation of the ball screw nut 33. In addition, a bearing that rotatably supports the ball screw 32 may be provided on the guide stand 13 of the column 4.

The motor 31 is provided, for example, on the guide stand 13 of the column 4. The rotational power of the motor 31 is transmitted by power transmission means such as pulleys 35, 36 and a belt 37 provided on the motor 31 and the ball screw nut 33. Specifically, a pulley 35 is provided on the output shaft of the motor 31, and a pulley 36 is provided near the upper end of the ball screw nut 33. A belt 37 that transmits power is hung between the pulleys 35 and 36.

The ball screw 32 that screws into the ball screw nut 33 of the feed mechanism 30 is provided in the chuck support part 14. Specifically, the ball screw 32 is fixed to the upper part of the chuck support part 14 so that it can move up and down coaxially with the chuck support part 14.

This configuration allows the power to move the chuck support part 14 in the vertical direction to be transmitted from the feed mechanism 30 to the chuck support part 14 while suppressing the inclination of the chuck support part 14. This allows the chuck 3 to be optimally fed in the vertical direction while suppressing inclination.

The feed mechanism 30 is not limited to a configuration of an electric motor 31 and a ball screw 32, but may be other driving means such as an air cylinder that uses air pressure or a hydraulic cylinder that uses hydraulic pressure.

FIG. 2 is a plan view showing a schematic configuration of the polishing apparatus 1. As shown in FIG.
1 and 2, as described above, the feed mechanism 30 is provided above the chuck support portion such that the ball screw 32 is concentric with the chuck support portion 14. That is, the ball screw 32 moves up and down about the same rotation axis as the rotation axis of the chuck 3. This makes it possible to suppress tilting of the chuck support portion 14 and increase rigidity.

The feed mechanisms 30 may be provided in pairs, arranged facing each other on both horizontal sides of the chuck support part 14, i.e., on the left and right sides of the chuck support part 14. By providing a pair of feed mechanisms 30 to sandwich the chuck support part 14, it is possible to apply vertical forces to the chuck support part 14 from both sides. Even with this configuration, compared to a configuration in which the feed mechanism 30 is arranged on only one side of the chuck support part 14, it is possible to suppress the inclination of the chuck support part 14 and efficiently feed a large workpiece W in the vertical direction.

Four guide mechanisms 20 are provided. That is, the guide mechanisms 20 are formed on four shafts extending in the vertical direction approximately parallel to the rotation axis of the chuck 3. In detail, the guide mechanisms 20 are arranged in four locations in total, two on the right side and two on the left side of the chuck support portion 14.

As described above, the four guide mechanisms 20 are arranged opposite each other with the chuck support portion 14 in between. More specifically, the two guide mechanisms 20 on each side are arranged so that the left and right guide mechanisms 20 face each other at positions offset forward and backward from the rotation axes of the chuck 3 and the chuck support portion 14. In other words, the guide mechanisms 20 formed on the four axes are arranged at four positions that are approximately symmetrical in the front-to-back direction and the left-to-right direction with respect to the rotation center of the chuck 3 and the chuck support portion 14.

As described above, each guide mechanism 20 formed on the four shafts is formed with a pair of upper and lower guides 21 (see Figure 1). That is, two guides 21 are formed on each of the four guide mechanisms 20, for a total of eight guides 21. This configuration allows for precision polishing with minimal inclination of the workpiece W.

FIG. 3 is a perspective view showing the guide 21 of the polishing apparatus 1. As shown in FIG.
3, the guide 21 is a linear guide that guides the vertical movement of the chuck support portion 14, and has a rail 24 that extends in the vertical direction, and a block 25 that is supported so as to be movable relatively to the rail 24. The block 25 is guided by the rail 24 and is movable relatively in the vertical direction.

Referring to Figures 1 to 3, this configuration allows the chuck 3 and chuck support 14 to move vertically with less frictional resistance in the guide 21, enabling efficient movement. In addition, the inclination of the chuck 3 and chuck support 14 can be effectively suppressed. This allows for efficient, high-precision polishing.

In this embodiment, the block 25 is fixed to the chuck support 14, and the rail 24 that guides the movement of the block 25 is fixed to the column 4 via the guide stand 13 or the like. This configuration makes it possible to effectively suppress the tilt of the chuck 3, and also reduces the height dimension of the components that can move up and down, such as the chuck support 14 that supports the chuck 3, enabling an optimal feed operation.

In addition, contrary to the present embodiment described above, a configuration may be adopted in which the block 25 is fixed to the column 4 via a guide stand 13 or the like, and the rail 24 that guides the block 25 is fixed to the chuck support portion 14.

The block 25 may also be provided with rolling elements such as balls (not shown) that roll in contact with the guide grooves of the rail 24. The rolling of the balls in the block 25 allows for suitable polishing with small vertical feed resistance and small inclination of the workpiece W. The block 25 may also be a linear guide that does not have rolling elements and uses sliding.

The rails 24 may also be configured so that a single rail 24 guides the upper guide 22 provided at the top of the guide mechanism 20 and the lower guide 23 provided at the bottom of the guide mechanism 20. In other words, a pair of upper and lower blocks 25 may be guided and fed by a single common rail 24.

Next, the polishing apparatus 101 will be described in detail with reference to Figs. 4 to 6 as an example of a modified embodiment. Note that components that have the same or similar functions and effects as those in the embodiment already described will be given the same reference numerals and their description will be omitted.

FIG. 4 is a front view showing a schematic configuration of a polishing apparatus 101 according to another embodiment of the present invention.
4, in the polishing apparatus 101, one feed mechanism 30 for feeding the chuck support portion 14 in the up and down direction is provided on one side of the chuck support portion 14. That is, the feed mechanism 30 is provided on the side of the spindle case 115 constituting the chuck support portion 14.

The motor 31 as a drive source for moving the chuck support portion 14 up and down may be connected to the ball screw 32 without using power transmission means such as the pulleys 35, 36 and belt 37 shown in FIG. 1. The ball screw 32 may be provided coaxially with the chuck support portion 14, as in the embodiment shown in FIG. 1. This makes it possible to suppress the inclination of the chuck support portion 14 and increase its rigidity. As described above, the feed mechanism 30 is not limited to a configuration of the electric motor 31 and ball screw 32, and may be, for example, an air cylinder, a hydraulic cylinder, or other drive means.

The guide 21 is a linear guide having rollers (not shown) as rolling elements. The slider (block 25) is provided with multiple mallet-shaped rollers that are held by a retainer (not shown) and move in an infinite circular motion around the outer periphery of a track (not shown). A guide 21 configured in this way allows for suitable polishing with small vertical feed resistance and small inclination of the workpiece W. Note that other types of linear guides may also be used as the guide 21.

FIG. 5 is a plan view showing a schematic configuration of the polishing apparatus 101. As shown in FIG.
5, the guide mechanisms 20 are provided at four locations. Specifically, the guide mechanisms 20 are disposed near the outer side of the guide stand 13 at 90 degree intervals around the rotation axis of the chuck 3.

FIG. 6 is a perspective view showing the spindle case 115 of the polishing apparatus 101. As shown in FIG.
6, the spindle case 115 constituting the chuck support portion 14 is formed in a substantially octagonal cylindrical shape. That is, the spindle case 115 has a substantially octagonal shape when viewed from above.

Referring to Figures 4 to 6, the guide mechanisms 20 are formed on four shafts that extend in the vertical direction and are approximately parallel to the rotation axis of the chuck 3. Specifically, the spindle case 115 is formed in a substantially octagonal cylindrical shape, and the guide mechanisms 20 are provided near the outer side of the spindle case 115 so as to face each other with the rotation axis of the chuck 3 at the center. In other words, the four guide mechanisms 20 are arranged to face each other with the rotation axis of the chuck 3 at the center.

Each guide mechanism 20 formed on the four shafts is formed with a pair of upper and lower guides 21. That is, two guides 21 are formed on each of the four guide mechanisms 20, and there are a total of eight guides 21. This configuration allows for precise polishing with minimal tilt of the workpiece W.

In this embodiment, the block 25 is fixed to the column 4 via the guide stand 13 or the like, and the guide surface 124 serving as a rail for guiding the movement of the block 25 is formed on the spindle case 115 of the chuck support portion 14. Note that, in contrast to the above configuration, a configuration may be adopted in which the block 25 is fixed to the spindle case 115, and the guide surface 124 serving as a rail for guiding the block 25 is formed on the guide stand 13 or the like and fixed to the column 4.

Also, a configuration may be adopted in which a single guide surface 124 guides an upper guide 22 provided at the top of the guide mechanism 20 and a lower guide 23 provided at the bottom of the guide mechanism 20. In other words, a pair of upper and lower blocks 25 may be guided and fed by a single common guide surface 124.

As described above, the polishing apparatus 1, 101 according to this embodiment can suppress the tilt of the chuck 3 with the guide mechanism 20. Therefore, even if a large force is applied, the tilt of the workpiece W can be suppressed, and high-precision polishing can be performed.

In the above, in this embodiment, a guide mechanism 20 having two guides 21, an upper guide 22 and a lower guide 23, is provided on four axes, and a total of eight guides 21 are provided, but the number and arrangement of the guides 21 are not limited to this.

For example, if a guide mechanism 20 with three or more axes is provided as a whole, the effect of suppressing tilt of the chuck 3 can be obtained. Also, instead of a guide mechanism 20 having two guides 21, an upper guide 22 and a lower guide 23, a guide mechanism 20 having one guide 21 may be used.

In addition, the shape of the spindle case 115 is not limited to an octagonal tube, and may be approximately cylindrical, approximately triangular, approximately square, or other angular tube shape, as long as a portion for attaching a specified guide mechanism 20 can be provided.

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.

Reference Signs List 1, 101 Polishing device 2 Table 3 Chuck 4 Column 5 Polishing cloth 11 Support 12 Upper plate 13 Guide stand 14 Chuck support portion 15, 115 Spindle case 20 Guide mechanism 21 Guide 22 Upper guide 23 Lower guide 24 Rail 25 Block 30 Feed mechanism 31 Motor 32 Ball screw 33 Ball screw nut 35 Pulley 36 Pulley 37 Belt 124 Guide surface W Workpiece

Claims (5)

A polishing apparatus for polishing a horizontally rotating plate-shaped workpiece by pressing the workpiece against an upper surface of a horizontally rotating polishing cloth, comprising:
a table that holds the polishing cloth on its upper surface and rotates horizontally;
a chuck that is provided above the table and that holds the workpiece and rotates horizontally;
a chuck support portion that supports the chuck so as to be horizontally rotatable;
a plurality of guide mechanisms disposed opposite each other across the chuck support portion and supporting the chuck support portion so as to be movable up and down;
a feed mechanism for feeding the chuck support portion in a vertical direction ,
At least one of the guide mechanisms is provided with a pair of upper and lower guides that support the chuck support portion ,
A polishing apparatus characterized in that the feed mechanism is provided above the chuck support portion so as to transmit power for moving the chuck support portion in the vertical direction to an upper portion of the chuck support portion which is concentric with the rotation axis of the chuck . The polishing device according to claim 1, characterized in that the guide has a rail extending in the vertical direction and a block supported so as to be movable relative to the rail. The polishing device according to claim 2, characterized in that the block is fixed to the chuck support. The polishing device according to claim 2 or 3, characterized in that the block is provided with a rolling element that rolls in contact with the rail. The polishing device according to any one of claims 1 to 4, characterized in that the guide mechanism is formed of four pieces.

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