JP2005271100A - Dressing device of polishing pad and polishing apparatus having dressing device of polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dressing device of a polishing pad, having a large effective area of a pad dresser and uniforming contact between the pad dresser and a polishing pad to thereby perform uniform and stable dressing for the polishing pad, and a polishing apparatus having the dressing device of the polishing pad. <P>SOLUTION: This dressing device of the polishing pad is provided in the polishing apparatus in which, while slurry is supplied, a work is polished in contact with the polishing pad. The dressing device includes: a dressing plate 22 formed of a disc-like metallic sheet where abrasive grains 80B are electro-deposited on the surface thereof; a backup plate 24 disposed at the back of the dressing plate; and a dressing device body 30A having a pressing mechanism for pressing the dressing plate through the backup plate. The dressing plate 22 is divided into two or more zones. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polishing pad dressing apparatus and a polishing apparatus having the polishing pad dressing apparatus, and more particularly to a polishing pad dressing apparatus suitable for chemical mechanical polishing (CMP) and a polishing pad dressing apparatus. The present invention relates to a polishing apparatus having

  In CMP, clogging of the polishing pad causes a reduction in the polishing rate and deteriorates the uniformity of polishing. Therefore, dressing (sharpening) of the polishing pad is indispensable. The dressing of the polishing pad is a slurry (abrasive material is made by contacting a dresser made of diamond or other abrasive grains against the polishing pad and scraping the surface of the polishing pad or roughening the surface of the polishing pad). This refers to a process for recovering the retainability of the dispersed solution and maintaining the polishing ability.

  As this dresser, a dresser or the like in which diamond abrasive grains are electrodeposited has been used. FIG. 5 shows a polishing apparatus 11 having a conventional pad dresser 90. The pad dresser 90 is electrodeposited with diamond abrasive grains 80B on the lower surface, or is composed of a bond layer (metal bond, vitrified bond or resin bond) in which the abrasive grains 80B are dispersed. The pad dresser 90 is pressed against the polishing pad 20 on the polishing surface plate 12 with a force F while being rotated about the shaft 92 to dress the polishing pad 20.

  The thickness of the pad dresser 90 is generally about 10 to 30 mm, and the outer diameter is generally about 100 to 250 mm (4 to 10 inches). The base of the pad dresser 90 is generally made of metal.

  As shown in FIG. 6, the pad dresser 90 and the shaft 92 are often connected via a flexible joint 94 (for example, a universal joint). With this configuration, the surface (lower surface) of the pad dresser 90 and polishing are performed. The surface of the pad 20 is in contact with the entire surface, and the surface of the pad dresser 90 follows the surface of the polishing pad 20 even during the dressing operation.

  Further, the present applicant has proposed a dressing apparatus that can improve the conventional pad dresser and perform uniform and stable dressing of the polishing pad (see Patent Document 1).

In this proposal, a dressing plate, a backup plate, a fixing ring, and the like are combined and the dressing plate is stretched to make the contact state between the dressing device (pad dresser) and the polishing pad uniform.
JP 2003-136403 A

  However, such a conventional pad dresser, particularly a pad dresser formed by electrodeposition of diamond abrasive grains, has the following problems.

  The polishing pad that is dressed by the pad dresser has a predetermined elasticity, and when the disk-shaped pad dresser is pressed, the polishing pad bends and deforms by a predetermined amount. And the reaction force corresponding to this bending deformation will act on the surface of a pad dresser.

  In this case, the reaction force acting on the edge portion of the pad dresser, that is, the peripheral portion of the pad dresser, is larger than the reaction force acting on the inside of the pad dresser in the circumferential direction. Therefore, the diamond abrasive grains on the periphery of the pad dresser contribute greatly to the dressing, and the diamond abrasive grains on the periphery of the pad dresser wear faster.

  In such a case, the pad dresser formed by electrodeposition of diamond abrasive grains has only one layer of diamond abrasive grains, and the life of the pad dresser is exhausted when the peripheral diamond abrasive grains are worn. It will be. The diamond abrasive grains in the circumferential direction of the pad dresser are not yet worn and are wasted.

  Therefore, some users use an annular pad dresser, for example, a donut-shaped pad dresser having an outer periphery of 100 mm and an annular width of 10 mm so as not to cause such waste. However, even in this case, the effective area of the pad dresser does not increase, the dressing performance is low, and improvement has been demanded.

  The present invention has been made in view of such circumstances, and the effective area of the pad dresser is large, and the contact between the pad dresser and the polishing pad becomes uniform, and as a result, polishing that enables uniform and stable dressing of the polishing pad. It is an object of the present invention to provide a pad dressing apparatus and a polishing apparatus having the polishing pad dressing apparatus.

  In order to achieve the above object, the present invention provides a polishing pad dressing apparatus in a polishing apparatus that polishes by contacting a work with a polishing pad while supplying slurry, and a disc-shaped metal having abrasive grains electrodeposited on its surface. A dressing plate made of a manufactured sheet, a backup plate disposed on the back surface of the dressing plate, and a dressing apparatus main body provided with a pressing mechanism disposed on the back surface of the backup plate and pressing the dressing plate via the backup plate; And a dressing apparatus for the polishing pad, wherein the dressing plate is divided into a plurality of zones, and a polishing apparatus having the dressing apparatus for the polishing pad.

  According to the present invention, a dressing plate made of a disk-shaped metal sheet having a surface electrodeposited with abrasive grains is divided into a plurality of zones. Accordingly, each zone of the dressing plate can follow the deformation of the polishing pad, the contact between the entire pad dresser and the polishing pad becomes uniform, and as a result, uniform and stable dressing of the polishing pad can be performed.

  In this invention, it is preferable that the said dressing board is divided | segmented concentrically. Thus, by dividing the dressing plate concentrically, each zone of the dressing plate easily follows the deformation of the polishing pad, and the contact between the entire pad dresser and the polishing pad becomes more uniform. Uniform and stable dressing of the polishing pad is possible.

  In addition, the division | segmentation method of a dressing board is not necessarily restricted to a concentric form, For example, various aspects, such as the division | segmentation method in which the radial cut | interruption entered from the center, are employable.

  Further, in the present invention, the pressing mechanism includes a circular flat concave portion formed on the lower surface of the dressing apparatus main body, the backup plate that covers the concave portion to form a sealed space, and a fluid pressure in the sealed space. It is preferable to comprise a pressurizing means for adding In this way, by using so-called airbag-type pressurizing means in combination, each zone of the dressing plate can more easily follow the deformation of the polishing pad, and the contact between the entire pad dresser and the polishing pad becomes more uniform. As a result, uniform and stable dressing of the polishing pad can be performed.

  As described above, according to the present invention, the dressing plate made of a disk-shaped metal sheet having abrasive grains electrodeposited on its surface is divided into a plurality of zones. Accordingly, each zone of the dressing plate can follow the deformation of the polishing pad, the contact between the entire pad dresser and the polishing pad becomes uniform, and as a result, uniform and stable dressing of the polishing pad can be performed.

  Hereinafter, preferred embodiments of a dressing apparatus for a polishing pad according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing the overall configuration of the polishing apparatus 10. As shown in FIG. 1, the polishing apparatus 10 is mainly composed of a polishing surface plate 12 and a wafer holding head 14 which is a holding head for holding a workpiece.

  The polishing surface plate 12 is formed in a disk shape, and a rotating shaft 16 is connected to the center of the lower surface thereof. The polishing surface plate 12 rotates in the direction of arrow A by driving a motor 18 connected to the rotating shaft 16. Further, a polishing pad 20 is affixed to the upper surface of the polishing surface plate 12, and a slurry (a solution in which an abrasive is dispersed) is provided on the polishing pad 20 from a nozzle (not shown) and is often a mechanochemical polishing agent. Is used). The wafer holding head 14 rotates in the arrow B direction around the rotation shaft 22A.

  2 and 3 show each aspect of a dressing device 30 (pad dresser) for a polishing pad according to the present invention. FIG. 2 is a front sectional view of the dressing device 30, and FIG. 3 is a bottom view of the dressing device 30.

  In FIG. 2, a dressing device 30 for a polishing pad includes a dressing plate 22 made of a disk-shaped metal sheet with electrodeposited abrasive grains 80B and a flexible sheet 24 as a backup plate disposed on the back of the dressing plate 22. And a dressing device main body 30 </ b> A provided with a pressing mechanism that is disposed on the back surface of the flexible sheet 24 and presses the dressing plate 22 through the flexible sheet 24.

  The dressing device body 30A is a metal disk-like member, and a drive shaft 92 is erected at the center of the upper surface. Further, a circular flat concave portion 30B is formed on the lower surface of the dressing apparatus main body 30A. A flexible sheet 24, which is a backup plate, is tightly fixed to the entire periphery of the lower surface of the dressing apparatus body 30A so as to form a sealed space covering the recessed portion 30B.

  The dressing apparatus main body 30A holds the flexible sheet 24 and the dressing plate 22, and the shape, material, etc. of other parts are not limited as long as the rotational force from the shaft 92 and the pressing pressure F can be reliably transmitted. Generally, it is made of metal.

  As a material of the flexible sheet 24, it is preferable that the A hardness defined by JIS K6301 is 10 to 90. If the flexible sheet 24 is made of such a material, the contact state between the dressing device 30 and the polishing pad 20 becomes non-uniform due to elastic deformation in combination with the configuration of the dressing plate 22 described later. Can be prevented.

  If the A hardness specified by JIS K6301 of the flexible sheet 24 is more than 90, the elastic deformation is insufficient, and the contact state between the dressing device 30 and the polishing pad 20 tends to be uneven, while the flexible sheet 24 has an A hardness. If the hardness is less than 10, the elastic deformation is too large and the contact state between the dressing device 30 and the polishing pad 20 tends to be unstable. In the range of the above A hardness (JIS K6301), the range of 20 to 50 is more preferable for exhibiting the function of the flexible sheet 24.

  The material of such a flexible sheet 24 can generally be selected from rubber materials, but may be a resin material or the like. Specifically, for example, silicone rubber, chloroprene rubber, chloroprene sponge, NBR (nitrile butadiene rubber) and the like can be suitably used.

  In addition, even if the flexible sheet 24 is a material in the range of the A hardness, if the thickness of the flexible sheet 24 is too small, the amount of elastic deformation becomes insufficient, and the function of the flexible sheet 24 is difficult to exhibit. Therefore, the thickness of the flexible sheet 24 is preferably in the range of 1 to 20 mm, and more preferably in the range of 5 to 10 mm.

  As a method for fixing the flexible sheet 24 to the periphery of the lower surface of the dressing apparatus main body 30A, various known methods such as adhesion can be employed.

  A pressurizing means for applying fluid pressure is connected to the sealed space formed by the recessed portion 30B of the dressing apparatus main body 30A and the flexible sheet 24. This pressurizing means includes an air supply line 26 and an air supply source 28.

  That is, an air supply line 26 is formed through the dressing apparatus main body 30 </ b> A, and a base end portion of the air supply line 26 is connected to an air supply source 28. Further, a rotary joint (not shown) is provided at the drive shaft 92 portion of the air supply line 26 so that air can be supplied to the air supply line 26 while the drive shaft 92 is rotating.

  With the above configuration, pressurized air can be supplied to the sealed space, and the flexible sheet 24 can be controlled to an arbitrary shape.

  The dressing plate 22 is made of a metal sheet having the surface electrodeposited with abrasive grains 80B so that the circle (a) in FIG. 2 is enlarged. As the abrasive grains 80B electrodeposited on the surface of the dressing plate 22, diamond is preferable. However, for example, CBN abrasive grains can also be used. Electrodeposition is a method of manufacturing a grinding / polishing tool using an electrolytic plating method, and nickel is generally used (refer to Glossary of Cutting / Grinding / Polishing Terminology: edited by the Abrasive Processing Society).

  The particle size of the abrasive grains 80B, the density of the abrasive grains 80B on the surface of the dressing plate 22, the material of the abrasive grains 80B, etc. may be selected appropriately in consideration of the material of the polishing pad 20 and the like.

  The material of the dressing plate 22 is required to be a conductive metal material based on the principle of electrodeposition, and various materials can be used, but stainless steel is preferable in terms of rust prevention, corrosion resistance, strength, and the like. The plate thickness of the dressing plate 22 is preferably selected in consideration of the size (outer diameter) of the dressing device 30, the pressing pressure F, the material of the dressing plate 22, and the like, but can be set to 3 mm, for example.

  As shown in FIG. 3, the dressing plate 22 is divided concentrically. That is, in FIG. 3, the dressing plate 22 is divided into four in the order of doughnut-shaped 22B, 22C, and 22D from the disc-shaped 22A at the center toward the outer peripheral side.

  These dressing plates 22A, 22B, 22C, 22D and the flexible sheet 24 are merely in contact with each other in the vertical direction. That is, the dressing plates 22A, 22B, 22C, and 22D are engaged in a so-called stamping method so that the inside of the circle (b) in FIG. 2 is enlarged. The outermost dressing plate 22D is supported by the lower end of the outer peripheral portion of the dressing apparatus main body 30A via the pin member 31.

  With such a configuration, the dressing plate 22 is concentrically divided so that the zones 22A, 22B, 22C, and 22D of the dressing plate can easily follow the deformation of the polishing pad 20.

  As another configuration, a conventional means can be used as a connection means between the dressing apparatus main body 30A and the shaft 92, but in order to prevent the contact state between the dressing apparatus 30 and the polishing pad 20 from becoming uneven, a flexible joint ( For example, it is preferable to be connected via a universal joint.

  The dressing device 30 is disposed beside the polishing device 10 (see FIG. 1), and the polishing pad 20 is dressed between polishing operations, or the polishing pad 20 is dressed during the polishing operation. Or

  According to the dressing apparatus 30 of FIG. 2 having the configuration described above, the dressing apparatus 30 is pressed against the polishing pad 20 with a predetermined force F while being rotated about the shaft 92 to dress the polishing pad 20. The zones 22A, 22B, 22C, 22D of the dressing plate 22 can follow the deformation of the polishing pad 20, and the contact between the entire pad dresser and the polishing pad 20 becomes uniform. As a result, the polishing pad 20 is uniform and stable. Can be dressed.

  Further, the entire surface of the dressing plate 22 contributes to the dressing of the polishing pad 20, so that the dressing speed is improved and the life of the dressing plate 22 is extended.

  Next, another embodiment of the dressing apparatus for the polishing pad according to the present invention will be described with reference to FIG. The same or similar members as those of the dressing apparatus 30 for the polishing pad shown in FIG.

  In this embodiment, the polishing pad dressing device 130 includes a dressing plate 22, a flexible sheet 124 having a predetermined thickness as a backup plate disposed on the back surface of the dressing plate 22, and a dressing device disposed on the back surface of the flexible sheet 124. The main body 130A is configured.

  The dressing apparatus main body 130A is a metal disk-shaped member having a predetermined thickness. And the flexible sheet 124 which is a backup board is closely_contact | adhered and fixed to the lower surface of the dressing apparatus main body 130A. Further, a dressing plate 22 divided into concentric zones 22A, 22B, 22C, and 22D is bonded and fixed to the lower surface of the flexible sheet 124.

  The flexible sheet 124 may be made of the same material as the flexible sheet 24 described above, but is preferably thicker than the flexible sheet 24, for example, having a plate thickness of 10 mm. By having a predetermined plate thickness as described above, the deformation of the polishing pad 20 can be followed, and the zones 22A, 22B, 22C and 22D of the dressing plate 22 adhered to the lower surface can follow the deformation of the polishing pad 20.

  Since the dressing plate 22 is bonded to the lower surface of the flexible sheet 124, the dressing plates 22 are enlarged and displayed in the circle (b) in FIG. 2 between the dressing plates 22A, 22B, 22C, and 22D. The so-called stamping type engagement is unnecessary.

  The configurations described above are examples of the present invention, but the present invention is not limited to these, and various configurations can be adopted.

  For example, the dividing method of the dressing plate 22 is not limited to a concentric circle, and various modes such as a dividing method in which a radial cut is formed from the center can be adopted.

  In the dressing device 30 shown in FIG. 2, a so-called airbag system is employed as the pressing mechanism, but it is not limited to gas, and pressurization with a liquid can also be employed.

  Furthermore, in the dressing device 130 shown in FIG. 4, the flexible sheet 124 is made of a uniform material having the same thickness, but instead, the elasticity gradually increases from the central portion toward the peripheral portion. It is possible to employ a configuration in which the slit is gradually reduced, a radial cut is formed from the center, and the cut is gradually spread from the center portion toward the peripheral portion. By adopting such a configuration, the peripheral portion is more easily bent than the central portion of the flexible sheet 124 and can easily follow the deformation of the polishing pad 20.

Perspective view showing the overall structure of the polishing apparatus Front sectional view showing a configuration example of a dressing device Bottom view showing a configuration example of a dressing device Front sectional view showing another configuration example of the dressing apparatus Schematic showing the overall structure of the dressing device Front view showing the configuration of a conventional dressing device

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Polishing apparatus, 20 ... Polishing pad, 22 ... Dressing board, 24, 124 ... Flexible sheet, 30, 130 ... Dressing apparatus, 30A, 130A ... Dressing apparatus main body

Claims (4)

In a polishing pad dressing apparatus in a polishing apparatus that polishes by contacting a work with a polishing pad while supplying slurry,
A dressing plate made of a disk-shaped metal sheet with abrasive grains electrodeposited on the surface;
A backup plate disposed on the back surface of the dressing plate;
A dressing device main body provided with a pressing mechanism that is arranged on the back surface of the backup plate and presses the dressing plate through the backup plate;
A dressing device for a polishing pad, wherein the dressing plate is divided into a plurality of zones.   The dressing apparatus of the polishing pad according to claim 1, wherein the dressing plate is divided concentrically.   The pressing mechanism includes a circular flat concave portion formed on the lower surface of the dressing apparatus main body, the backup plate that covers the concave portion to form a sealed space, and a pressurizing unit that applies fluid pressure to the sealed space. The polishing pad dressing device according to claim 1 or 2, further comprising:   A polishing apparatus comprising the polishing pad dressing apparatus according to claim 1, 2 or 3.

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