JP2009202325A - Polishing head, polishing device, and polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing head capable of freely controlling a global configuration of a workpiece by polishing. <P>SOLUTION: The polishing head is used for holding the workpiece whose surface is put in sliding contact with an abrasive cloth affixed on a surface plate at the time of polishing, and includes at least: a carrier for holding the workpiece; a first pressure adjustment mechanism for pressing an outer peripheral portion of the carrier; and a second pressure adjustment mechanism for pressing a center portion of the carrier. Each of the first pressure adjustment mechanism and the second pressure adjustment mechanism can press the carrier independently, so that when the workpiece is put in sliding contact with the abrasive cloth and is polished, pressing forces of the carrier to the workpiece can be made different on the inside and outside in the carrier plane, and the workpiece can be put in sliding contact with the abrasive cloth at different pressing forces on the inside and outside in the wafer plane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing head for holding a workpiece when polishing the surface of the workpiece, a polishing apparatus including the same, and a polishing method using the same.

As a device for polishing the surface of a workpiece such as a silicon wafer, there are a single-side polishing device for polishing a workpiece one side at a time and a double-side polishing device for polishing both surfaces simultaneously.
For example, as shown in FIG. 9, a general single-side polishing apparatus includes a surface plate 43 to which a polishing cloth 44 is attached, an abrasive supply mechanism 56, a polishing head 30, and the like. In such a polishing apparatus 51, the workpiece W is held by the polishing head 30, the polishing agent 55 is supplied from the polishing agent supply mechanism 56 onto the polishing cloth 44, and the surface plate 43 and the polishing head 30 are rotated to rotate the workpiece. Polishing is performed by bringing the surface of W into sliding contact with the polishing pad 44.

As a method of holding the work, there are a method of attaching a work to a flat disk-shaped plate through an adhesive such as wax, a method of attaching water with a soft pad (backing pad), a method of vacuum suction, and the like.
In FIG. 9, this polishing head 30 has an elastic pad (backing pad) 38 made of polyurethane or the like attached to the lower surface of a disk-shaped carrier 39 made of ceramics or the like. Is held by surface tension. Further, a ring (guide ring) 37 is provided around the carrier 39 in order to prevent the workpiece W from being detached from the carrier 39 during polishing.

Further, a polishing head as shown in FIG. 10 has been proposed. The polishing head 40 is rotatably supported by a shaft body 31 attached to a pressing mechanism (not shown), a rubber sheet 32 attached to the shaft body 31, and the rubber sheet 32. A carrier 36 and a guide ring 37, and a backing pad 38 under the carrier 36 are provided. A chamber 39 sealed with the shaft 31 and the rubber sheet 32 is formed.
When such a polishing head 40 is used, the workpiece W is held by the backing pad 38, the pressure in the chamber 39 is controlled by the pressure adjustment mechanism 41, and the workpiece W is pressed against the polishing cloth 44 via the carrier 36. It is to be polished.
In addition, there has been proposed a polishing head that includes three chambers and can hold the workpiece flat by adjusting the pressure of the chambers (see Patent Document 1).

JP 2001-358103 A

However, although the polishing head as described above has many pressure systems other than those shown in the figure, the pressure system for pressurizing the workpiece, that is, for pressurizing the carrier, is only one line for controlling the pressure of the chamber. Met.
When polishing is performed using such a polishing head, the pressure applied to the workpiece is controlled only by this one line, and there is a problem that pressure cannot be applied uniformly within the workpiece surface. For this reason, the global shape of the workpiece (flatness within the workpiece surface) is determined by the structure of the polishing head and the accuracy of assembly, and the global shape of the workpiece cannot be freely controlled by polishing.

  In view of the above problems, the present invention provides a polishing head capable of freely controlling the global shape of a workpiece by polishing, a polishing apparatus including such a polishing head, and a polishing method using the same. For the purpose.

  In order to solve the above-described problems, the present invention provides a polishing head for holding the workpiece when the workpiece surface is slidably contacted with an abrasive cloth affixed on a surface plate, and is at least rotatable. A shaft body attached to the pressing mechanism, a head body connected to the shaft body via a first rubber sheet, and a second rubber sheet attached to the lower surface of the head body, A disc-shaped carrier attached to the lower surface of the second rubber sheet and held on the second rubber sheet via a gasket, and a surface for holding the work of the carrier along the outer periphery of the carrier A guide ring that protrudes downward and holds the edge portion of the workpiece; and a backing pad attached to the lower surface of the carrier; the shaft body, the first rubber sheet, and the head book A first chamber sealed by the first main body and a second chamber sealed by the second rubber sheet are formed, and the diameter of the second chamber is the workpiece to be held. The first chamber is provided with a first pressure adjusting mechanism, the second chamber is provided with a second pressure adjusting mechanism, and the first chamber is provided with the first pressure adjusting mechanism. By adjusting the adjusting mechanism, the outer peripheral portion of the carrier is pressed through the gasket to press the workpiece, and the second chamber adjusts the second pressure adjusting mechanism to adjust the second pressure. A polishing head is provided, wherein a pressing force is applied to the workpiece by pressing a center portion of the carrier through a rubber sheet.

In the present invention, two chambers are provided, the diameter of one chamber is made smaller than the diameter of the workpiece to be polished, the pressure system (pressure adjusting mechanism) for pressurizing the carrier in the polishing head is provided, and the diameter is The polishing head is characterized in that the pressure inside each chamber can be adjusted so that the chamber smaller than the workpiece presses the central portion of the carrier and the other chamber presses the outer peripheral portion of the carrier.
By using the polishing head having such a structure, it is possible to change the pressing force between the center and the outer periphery of the carrier, and thus it is possible to freely change the shape (unevenness) in the plane of the carrier. Since the workpiece to be polished is pressed against the polishing cloth by the carrier via the backing plate, if the carrier shape changes, the pressing force on the workpiece also changes following the change, and the shape of the workpiece after polishing also changes. Can be made. This makes it possible to make the polishing allowance uniform within the workpiece surface or change it within the workpiece surface, allowing the global shape of the workpiece to be freely controlled not only by the polishing head structure and assembly accuracy, but also by polishing. It is a head.

Further, in the present invention, a polishing apparatus for use in polishing the surface of a workpiece, which is at least an abrasive cloth affixed on a surface plate, and an abrasive for supplying the abrasive onto the abrasive cloth A polishing apparatus comprising the polishing head according to the present invention as a supply mechanism and a polishing head for holding the workpiece is provided.
As described above, according to the polishing apparatus equipped with the polishing head of the present invention, the shape of the carrier holding the workpiece can be controlled by adjusting / changing the pressure of the chamber, so that the workpiece is pressed against the polishing cloth. The pressure can be controlled in the workpiece surface, and thus the global shape of the workpiece to be polished can be freely controlled.

  According to the present invention, there is also provided a method for polishing a surface of a workpiece, wherein the workpiece is held by the polishing head according to the present invention, and the carrier is interposed through the gasket by adjusting the first pressure adjustment mechanism. Press the outer peripheral portion of the carrier and adjust the second pressure adjusting mechanism to press the center portion of the carrier via the second rubber sheet, and the work piece held by the carrier is placed on the surface plate. A work polishing method is provided, wherein the workpiece is polished by sliding with a predetermined pressing force while rotating with respect to the upper polishing cloth.

  As described above, the polishing head according to the present invention adjusts the pressure of the first chamber and the second chamber by adjusting the shape of the carrier of the polishing head by the first pressure adjusting mechanism and the second pressure adjusting mechanism. Can be controlled. Therefore, the shape of the carrier can be controlled, and thus the global shape of the workpiece can be freely controlled by adjusting the pressing force in the plane of the workpiece.

At this time, by changing the outer diameter and / or inner diameter of the gasket, the pressing force of the carrier outer peripheral portion and the carrier central portion can be adjusted (Claim 4).
In the polishing head of the present invention, the first chamber presses the outer peripheral portion of the carrier via the gasket by adjusting the first pressure adjusting mechanism to apply a pressing force to the workpiece. At this time, by changing the outer diameter and / or inner diameter of the gasket, the area covered by the pressing force to the outer peripheral portion of the carrier can be changed. Although the carrier is held on the second rubber sheet via the gasket, the second chamber is a space sealed by the second rubber sheet in contact with the head body and the gasket. As the diameter and / or inner diameter changes, the spatial volume of the second chamber changes. By changing the spatial volume, the area where the second chamber presses the carrier changes, and thus the pressing force to the center of the carrier can be changed by changing the outer diameter and / or inner diameter of the gasket. Thus, the pressing force of the carrier outer peripheral portion and the central portion can be adjusted by changing the outer diameter and / or inner diameter of the gasket.

At this time, by adjusting the first pressure adjusting mechanism and the second pressure adjusting mechanism, the pressure of the first chamber is made lower than the pressure of the second chamber, so that the outer periphery of the workpiece is removed. It can be made into a shape (Claim 5). Further, by adjusting the first pressure adjusting mechanism and the second pressure adjusting mechanism, the pressure of the first chamber is made higher than the pressure of the second chamber, so that the outer periphery of the workpiece is sag-shaped. (Claim 6).
In the polishing head of the present invention, the first chamber presses the outer periphery of the carrier by the first pressure adjustment mechanism, and the second chamber presses the center of the carrier by the second pressure adjustment mechanism. Here, when the pressure in the first chamber is made lower than the pressure in the second chamber, the pressing force on the outer periphery of the carrier becomes smaller than the pressing force on the center of the carrier, and the carrier has a shape in which the center is raised. . When a carrier having such a shape is used, when the workpiece is polished, the center portion is strongly pressed, and the outer periphery becomes a honeycomb shape. Also, if the pressure in the first chamber is made higher than the pressure in the second chamber, the pressing force on the outer periphery of the carrier becomes larger than the pressing force on the center of the carrier, and the carrier is recessed when the center is relatively viewed Become a shape. When a carrier having such a shape is used, the outer periphery of the work is strongly pressed and polished, and the outer periphery becomes a sagging shape.

  Further, in the present invention, a polishing head for holding the workpiece when the surface of the workpiece is polished by being brought into sliding contact with a polishing cloth affixed on a surface plate, and at least for holding the workpiece. A carrier, a first pressure adjusting mechanism for pressing the outer peripheral portion of the carrier, and a second pressure adjusting mechanism for pressing the center portion of the carrier, the first pressure adjusting mechanism; Each of the second pressure adjusting mechanisms can press the carrier independently, so that the carrier can be moved inside and outside the carrier surface when the workpiece is polished by sliding the workpiece against the polishing cloth. Provided is a polishing head characterized in that the pressing force to the workpiece can be made different, and can be brought into sliding contact with the polishing cloth with different pressing forces inside and outside the wafer surface ( Claim 7).

  The polishing head having such a structure can change the pressing force between the center portion and the outer periphery of the carrier, and can thus freely change the in-plane shape and flatness of the carrier. When the carrier shape changes, the pressing force to the workpiece can be changed following the change, and the shape of the workpiece after polishing can also be changed. Therefore, the polishing allowance can be made uniform within the workpiece surface or can be changed, and the polishing head is capable of freely controlling the global shape of the workpiece by polishing.

  As described above, the polishing head of the present invention can change the pressing force of the center part and the outer peripheral part of the carrier by changing the pressure of each chamber, and thus the shape (unevenness) in the plane of the carrier. Can be changed freely. When the carrier shape changes, the pressing force on the workpiece changes following the change, and the workpiece shape can be changed in the plane. Thereby, the polishing allowance in the work surface can be made uniform or changed in the surface, and the global shape of the work can be freely controlled by polishing.

Hereinafter, the present invention will be described more specifically.
As described above, the development of a polishing head that can freely control the global shape of a workpiece by polishing has been awaited.

  Therefore, the inventors of the present invention have made extensive studies, and as a result, the polishing head is provided with two pressure adjusting mechanisms, one of which is the outer periphery of the carrier for holding the workpiece and the other is the inner periphery of the carrier. By placing and pressing so as to pressurize, you can freely change the in-plane shape of the carrier, thereby changing the pressing force on the workpiece in the plane and adjusting the polishing allowance in the workpiece surface, The present invention has been completed by discovering that the global shape of the workpiece can be freely controlled as well as flattened.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a schematic sectional view showing an example of the polishing head of the present invention.
The polishing head 10 of the present invention includes a shaft body 11 that is rotatable and attached to a pressing mechanism 25, a head body 13 that is connected to the shaft body 11 via a first rubber sheet 12, and a head body. A second rubber sheet 14 attached to the lower surface of the main body 13, a disk-like carrier 16 attached to the lower surface of the second rubber sheet 14 and held on the second rubber sheet 14 via a gasket 15; The carrier 16 has a guide ring 17 that protrudes downward from the outer peripheral portion of the surface that holds the workpiece W and holds the edge portion of the workpiece W, and a backing pad 18 that is attached to the lower surface of the carrier 16.
In addition, a first chamber 19 sealed by the shaft body 11, the first rubber sheet 12, and the head body 13 is formed. And the 2nd chamber 20 sealed with the head main body 13 and the 2nd rubber sheet 14 is formed.

  The diameter of the second chamber 20 is smaller than the diameter of the workpiece W to be held. The first chamber 19 has a first pressure adjusting mechanism 21 via a flow path 29 and the second chamber 20 has a second diameter. The pressure adjusting mechanism 22 is provided via a flow path 31. The first chamber 19 adjusts the first pressure adjusting mechanism 21 to press the outer peripheral portion of the carrier 16 through the gasket 15 to transmit the pressing force to the workpiece W. The second chamber 20 By adjusting the pressure adjusting mechanism 22, the center portion of the carrier 16 can be pressed via the second rubber sheet 14 to apply a pressing force to the workpiece W. Further, the diameter of the second chamber 20 is smaller than the diameter of the workpiece W to be held, so that the center portion of the carrier 16 and the center portion of the workpiece W can be pressed. Each pressure adjusting mechanism may supply a pressurized fluid, such as air, to each chamber.

In the polishing head 10 having such a structure, the pressure at which the first chamber 19 presses the outer peripheral portion of the carrier 16 is set to the pressure at which the second chamber 20 presses the central portion of the carrier 16 by the first pressure adjusting mechanism 21. Can be adjusted independently by the second pressure adjusting mechanism 22. Accordingly, it is possible to change the pressing force between the center portion and the outer peripheral portion of the carrier 16, and thus the in-plane shape of the carrier 16 can be freely changed.
Here, since the workpiece W to be polished is slidably contacted with the polishing cloth 24 on the surface plate 23 by the carrier 16 via the backing plate 18, when the shape of the carrier 16 changes, the polishing cloth 24 follows the change. The pressing force against the surface also changes, and the in-plane shape of the workpiece W after polishing also changes. Thereby, the grinding allowance in the surface of the workpiece | work W can be adjusted. Therefore, the polishing head can control the global shape of the workpiece W by polishing only by the structure and assembly accuracy of the polishing head. Therefore, it is possible to obtain a flat wafer by uniformizing the machining allowance in the surface of the workpiece, and it is also possible to easily obtain a polished wafer or a bent wafer according to the purpose. .

Here, as shown in FIG. 2A, the outer diameter of the gasket 15 is a structure in which the second rubber sheet 14 and the guide ring 17 are provided via the gasket 15 by increasing the outer diameter. It can be. Further, as shown in FIG. 2B, the second rubber sheet 14 and the guide ring 17 are provided such that a part thereof is in direct contact without the gasket 15 by reducing the outer diameter of the gasket. It can also be. FIG. 2 is a schematic sectional view showing another example of the polishing head of the present invention.
Further, the spatial volume of the second chamber 20 can be changed by changing the inner diameter of the gasket 15.
By changing the outer diameter and / or inner diameter of the gasket 15 in this way, the region of the pressing force applied to the carrier 16 by the first pressure adjusting mechanism 21 and the second pressure adjusting mechanism 22 can be changed, and more finely. The distribution of the in-plane pressing force can be adjusted, and thus the in-plane shape of the work holding surface of the carrier can be freely controlled.

FIG. 3 is a schematic sectional view showing an example of a polishing apparatus provided with the polishing head according to the present invention. The polishing apparatus 26 includes a surface plate 23 to which a polishing cloth 24 is attached, an abrasive supply mechanism 27 for supplying an abrasive 28, and the polishing head 10 of the present invention as shown in FIG. ing.
According to such a polishing apparatus provided with the polishing head of the present invention, the carrier shape can be changed by adjusting the pressure of the chamber. Therefore, the global shape of the workpiece to be polished can be freely controlled.

As described above, the polishing head of the present invention includes the carrier for holding the workpiece, the first pressure adjusting mechanism for pressing the outer peripheral portion of the carrier, and the second for pressing the center portion of the carrier. The first pressure adjusting mechanism and the second pressure adjusting mechanism can each be a polishing head that presses the carrier independently.
In the polishing head having such a structure, when the carrier is polished by sliding the workpiece against the polishing cloth, the pressing force to the workpiece can be made different inside and outside the carrier surface. It can be brought into sliding contact with the polishing cloth with different pressing forces inside and outside.
In the polishing head having such a structure, the in-plane shape of the carrier can be freely changed, and thus the shape of the workpiece after polishing can be flattened or changed according to the purpose. Therefore, the polishing head can be made uniform or changeable in the work surface.

  An example of the workpiece polishing method of the present invention using the polishing head of the present invention as described above is shown below, but the present invention is not limited to these.

In order to polish the wafer W using the polishing apparatus 26 as shown in FIG. 3, first, the wafer W is attached to a backing pad soaked with water, the back surface of the wafer W is held by a carrier, and the edge of the wafer W is Hold the part with the guide ring. Then, the abrasive 28 is supplied from the abrasive supply mechanism 27 onto the polishing cloth 24, and the wafer W is brought into sliding contact with the polishing cloth 24 while rotating the polishing head 10 and the surface plate 23 in predetermined directions.
At this time, by adjusting the pressures of the sealed first chamber and second chamber of the polishing head 10 with the first pressure adjusting mechanism and the second pressure adjusting mechanism, respectively, the first chamber and the second chamber are adjusted. The chamber pressure can be freely controlled.

As described above, the polishing head 10 of the present invention has a desired carrier shape by adjusting the pressures of the first chamber and the second chamber by adjusting the first pressure adjusting mechanism and the second pressure adjusting mechanism. The shape can be adjusted. Therefore, the in-plane shape of the carrier can be controlled only by adjusting and changing the pressures of the first chamber and the second chamber, and as a result, the global shape of the workpiece W can be freely controlled.
The polished wafer can be easily separated by spraying water between the guide ring and the edge portion of the wafer W.

Here, by changing the diameter of the gasket, it is possible to adjust the pressing force against the workpiece W at the outer peripheral portion and the central portion of the carrier.
In the polishing head 10 as shown in FIG. 1 and FIG. 2B, the first chamber 19 presses the outer peripheral portion of the carrier 16 through the gasket 15 to apply a pressing force to the workpiece W. At this time, if the diameter of the gasket 15 is changed, the area covered by the pressing force to the outer peripheral portion of the carrier 16 can be changed. Further, the carrier 16 is held on the second rubber sheet 14 via the gasket 15, but the second chamber 20 is sealed by the second rubber sheet 14 and the head body 13 that are in contact with the gasket 15. It is space. Here, for example, when the diameter of the gasket 15 is changed as shown in FIG. 2A, the space volume of the second chamber 20 is changed, and the area where the second chamber 20 presses the carrier 16 is changed. The central pressing force changes. As described above, the pressing force of the outer peripheral portion and the central portion of the carrier 16 can be adjusted by changing the diameter of the gasket 15. In this way, the global shape of the carrier can be controlled more freely, and thus the in-plane shape of the workpiece can be more freely controlled.

  Further, by adjusting the first pressure adjusting mechanism 21 and the second pressure adjusting mechanism 22, not only the planar shape of the workpiece is flattened, but also the pressure in the first chamber 19 is made higher than the pressure in the second chamber 20. By making it low, the outer periphery of the workpiece W can be shaped like a honey. Further, by adjusting the first pressure adjusting mechanism 21 and the second pressure adjusting mechanism 22, the pressure of the first chamber 19 is made higher than the pressure of the second chamber 20, so that the outer periphery of the work W is sagging. It can also be.

In the polishing head of the present invention, the first chamber 19 presses the outer periphery of the carrier 16 by the first pressure adjusting mechanism 21, and the second chamber 20 presses the second rubber sheet 14 by the second pressure adjusting mechanism 22. The center part of the carrier 16 can be pressed via Therefore, when the periphery of the workpiece W to be polished is sagging, by increasing the pressure in the second chamber and polishing at a relatively lower pressure in the first chamber, a flat wafer is obtained after polishing. Can be obtained.
When the pressure in the first chamber 19 is lower than the pressure in the second chamber 20, the pressing force at the center of the carrier 16 becomes larger than the pressing force at the outer periphery, and the carrier 16 has a shape in which the center is raised. become. When the carrier 16 having such a shape is used, when the workpiece W is polished, the center portion is strongly pressed, and the outer periphery becomes a honey shape.
Conversely, if the pressure in the first chamber 19 is higher than the pressure in the second chamber 20, the pressing force at the outer peripheral portion of the carrier 16 becomes larger than the pressing force at the central portion, and the carrier 16 is relatively positioned at the central portion. It becomes a depressed shape. When the carrier 16 having such a shape is used, the outer periphery of the workpiece W is strongly pressed and polished, so that the outer periphery has a sagging shape.
In this way, the shape of the workpiece W after polishing can be made a desired shape by adjusting the first pressure adjusting mechanism 21 and the second pressure adjusting mechanism 22.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
(Examples 1 and 2)
A polishing head having the configuration shown in FIG. 1 was produced. Here, as shown in FIGS. 2A and 2B, a gasket having an outer diameter of 336 mm (Example 1: FIG. 2A) and an outer diameter of 291 mm (Example 2: (FIG. 2B)), A polishing head was prepared using a gasket having the same inner diameter of 269 mm, and a silicon wafer having a diameter of 300 mm was polished after the two types of polishing heads were installed in a polishing apparatus. The type used was an alkaline solution containing colloidal silica, and the polishing head and the polishing platen were each rotated at 30 rpm during polishing, and the polishing pressure of the wafer was 300 g. / Cm ² .
The following evaluation was performed before and after the polishing step.

  In order to confirm the amount of deformation of the carrier due to the pressure difference between the first chamber and the second chamber, the polishing head of Example 1 was inverted (turned over), and the first chamber and the second chamber were pressurized respectively. Flatness was measured. The measurement length was 310 mm, and the measurement locations were measured in four directions every 45 °. The outline is shown in FIG. FIG. 4 is a diagram showing an outline of an evaluation method for confirming the deformation amount of the carrier due to the pressure difference between the second chamber and the first chamber. The pressure was evaluated by fixing the pressure in the first chamber at 38 kPa and changing the pressure in the second chamber to 0, 20, 40, and 60 kPa. For evaluation, a simple jig was prepared, and the carrier surface was measured with a NANOWAY device (manufactured by Kyocera Corporation). FIG. 5 shows the evaluation result of the deformation amount of the carrier due to the pressure difference between the second chamber and the first chamber. 5A, the pressure in the second chamber is 0 kPa, (b) is 20 kPa, (c) is 40 kPa, and (d) is 60 kPa. Moreover, it is an evaluation result of a polishing head in two directions among four directions.

When the produced polishing head was used, the following evaluation was performed in order to confirm how much the carrier flatness differs depending on the gasket outer diameter when the carrier shape was changed.
The polishing head of Example 1 was mounted on a polishing apparatus, a silicon wafer was mounted on the polishing head, and a surface pressure gauge (manufactured by Nitta Corporation) was set on the polishing cloth. Thereafter, the pressure distribution in the silicon wafer surface was evaluated by applying an actual load. FIG. 6 is a distribution diagram showing the pressing force in the silicon wafer surface when the pressure in the second chamber is changed. FIG. 7 shows a graph comparing how the flatness of the carrier differs between the polishing heads of Example 1 and Example 2. Here, the pressure of the first chamber was fixed at 35 kPa, and the pressure of the second chamber was (a) 0 kPa, (b) 18 kPa, (c) 35 kPa, and (d) 50 kPa.

When the polishing was actually performed and the pressure ratio between the first chamber and the second chamber was changed, the following evaluation was performed in order to confirm the change in the machining allowance in the surface of the silicon wafer.
The silicon wafer was polished by a polishing apparatus equipped with the polishing head of Example 2. Then, the flatness of the silicon wafer before and after polishing was measured to evaluate the differential shape before and after polishing. An AFS apparatus (manufactured by ADE) was used for measuring the flatness. Here, the pressure of each chamber was fixed to 35 kPa for the first chamber, and (b) 18 kPa, (c) 35 kPa, and (d) 50 kPa for the second chamber. The result is shown in FIG. FIG. 8 is a graph showing the difference in how much the machining allowance in the surface of the silicon wafer is changed when the pressure in the second chamber is changed in the polishing head of Example 2.

  As shown in FIG. 5, (a) the flatness R of the carrier at 0 kPa (the average of the maximum values of the unevenness in the in-plane four-direction measurement) is −55.9 μm, and (b) at 18 kPa. R is -42.3 μm, (c) R is −32.0 μm at 35 kPa, (d) R is −21.5 μm at 50 kPa, and the carrier is flatter as the pressure in the second chamber is increased. It became clear that the difference in height between the outer periphery and the center decreased.

  Moreover, as shown in FIG. 6, in the case of (a), the pressing force is different between the outer peripheral portion and the central portion. However, it was found that as the pressure in the second chamber was increased, the pressing force at the outer peripheral portion and the central portion became the same level.

And as shown in FIG. 7, it turned out that the carrier shape of Example 1 and Example 2 in which the diameter of a gasket differs is different. Thus, the initial value of the carrier deformation amount can be determined by changing the outer diameter and / or inner diameter of the gasket. It was also found that when the second chamber pressure was increased, the carrier gradually changed to a convex shape at the center.
This is the same tendency as the result of evaluating the carrier shape, and it has been found that the carrier shape can actually be changed by changing the pressure in the first chamber and the second chamber. Here, in the graph of FIG. 7, the horizontal axis is the pressure of the second chamber, and the vertical axis is the difference in the maximum value of the unevenness of the carrier. On the vertical axis, the carrier becomes convex as it goes up and concave as it goes down.

  And as shown in FIG. 8, it turned out that the differential shape of the silicon wafer before and behind grinding | polishing changes by changing the pressure of a 2nd chamber. For example, when the pressure in the second chamber was 18 kPa (b), the shape of the outer peripheral portion of the wafer was hardly changed before and after polishing, but at 50 kPa (d), it was found that the shape was a honeycomb. Thus, it was confirmed that the shape of the wafer was controlled by the polishing head of the present invention. Here, in the graph of FIG. 8, the horizontal axis indicates the position in the radial direction from the center of the silicon wafer, and the vertical axis indicates the difference in wafer height before and after polishing.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

It is the schematic sectional drawing which showed an example of the grinding | polishing head of this invention. It is the schematic sectional drawing which showed another example of the grinding | polishing head of this invention. It is the schematic which shows an example of the grinding | polishing apparatus provided with the grinding | polishing head concerning this invention. It is the figure which showed the outline of the evaluation method of the deformation amount of the carrier by the pressure difference of a 1st chamber and a 2nd chamber. It is the figure which showed the result of having evaluated the deformation amount of the carrier by the pressure difference of the 1st chamber in Example 1, 2 and a 2nd chamber. The distribution map which showed the pressing force in the silicon wafer surface when changing the pressure of a 2nd chamber is shown. The graph which evaluated how much the flatness of a carrier differs in the polishing head of Example 1 and Example 2 is shown. 6 is a graph showing how much the in-plane shape of a silicon wafer changes when the pressure in the second chamber is changed in the polishing head of Example 2. It is the schematic sectional drawing which showed an example of the grinding | polishing apparatus provided with the conventional grinding | polishing head. It is the schematic sectional drawing which showed another example of the conventional grinding | polishing head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Polishing head, 11 ... Shaft body, 12 ... First rubber sheet, 13 ... Head body, 14 ... Second rubber sheet, 15 ... Gasket, 16 ... Carrier, 17 ... Guide ring, 18 ... Backing pad, 19 DESCRIPTION OF SYMBOLS 1st chamber, 20 ... 2nd chamber, 21 ... 1st pressure adjustment mechanism, 22 ... 2nd pressure adjustment mechanism, 23 ... Surface plate, 24 ... Polishing cloth, 25 ... Pressing mechanism, 26 ... Polishing apparatus 27 ... Abrasive supply mechanism, 28 ... Abrasive, 29 ... Flow path, 31 ... Flow path, W ... Workpiece.

Claims (7)

A polishing head for holding the workpiece when the surface of the workpiece is polished by being brought into sliding contact with a polishing cloth affixed on a surface plate,
At least a shaft that is rotatable and attached to the pressing mechanism;
A head body connected to the shaft body via a first rubber sheet and held;
A second rubber sheet attached to the lower surface of the head body;
A disc-shaped carrier attached to the lower surface of the second rubber sheet and held on the second rubber sheet via a gasket;
A guide ring that protrudes downward from the surface of the carrier that holds the workpiece along the outer periphery of the carrier and holds the edge of the workpiece;
A backing pad attached to the lower surface of the carrier;
A first chamber sealed by the shaft body, the first rubber sheet, and the head body is formed, and a second chamber sealed by the head body and the second rubber sheet is formed. And the diameter of the second chamber is smaller than the diameter of the workpiece to be held,
The first chamber is provided with a first pressure adjusting mechanism, and the second chamber is provided with a second pressure adjusting mechanism,
The first chamber adjusts the first pressure adjusting mechanism to press the outer peripheral portion of the carrier through the gasket to press the workpiece, and the second chamber presses the second pressure. A polishing head, wherein an adjustment mechanism is adjusted to press the center portion of the carrier via the second rubber sheet to apply a pressing force to the workpiece.   A polishing apparatus for use in polishing the surface of a workpiece, comprising at least an abrasive cloth affixed on a surface plate, an abrasive supply mechanism for supplying an abrasive onto the abrasive cloth, and the workpiece A polishing apparatus comprising: the polishing head according to claim 1 as a polishing head for holding the surface.   A method for polishing a surface of a workpiece, wherein the workpiece is held by the polishing head according to claim 1 and the outer peripheral portion of the carrier is pressed through the gasket by adjusting the first pressure adjusting mechanism. Further, by adjusting the second pressure adjusting mechanism, the center portion of the carrier is pressed through the second rubber sheet, and the work held by the carrier is applied to the polishing cloth on the surface plate. A method for polishing a workpiece, wherein the workpiece is slid and brought into contact with a predetermined pressing force while rotating.   4. The workpiece polishing method according to claim 3, wherein the pressing force of the carrier outer peripheral portion and the carrier central portion is adjusted by changing the outer diameter and / or inner diameter of the gasket.   By adjusting the first pressure adjusting mechanism and the second pressure adjusting mechanism, the pressure of the first chamber is made lower than the pressure of the second chamber, so that the outer periphery of the work is shaped like a honey. The method for polishing a workpiece according to claim 3 or 4, wherein the workpiece is polished.   By adjusting the first pressure adjusting mechanism and the second pressure adjusting mechanism, the pressure of the first chamber is made higher than the pressure of the second chamber, so that the outer periphery of the workpiece is sag shaped. The method for polishing a workpiece according to claim 3 or 4, wherein the workpiece is polished. A polishing head for holding the workpiece when the surface of the workpiece is polished by being brought into sliding contact with a polishing cloth affixed on a surface plate,
At least a carrier for holding the workpiece, a first pressure adjusting mechanism for pressing the outer periphery of the carrier, and a second pressure adjusting mechanism for pressing the center of the carrier ,
The first pressure adjustment mechanism and the second pressure adjustment mechanism can each independently press the carrier, whereby the carrier is slid in contact with the polishing cloth and polished. The pressing force to the workpiece can be made different inside and outside the carrier surface, and can be brought into sliding contact with the polishing cloth with different pushing force inside and outside the wafer surface. And polishing head.

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