TW200922744A - Grinding head and the grinding device - Google Patents

Abstract

The present invention provides a grinding head, which is a grinding head consisting of at least a middle plate having a roughly round disc shape and a rubber membrane covering at least a bottom surface portion and a side surface portion of the middle plate, having a space portion defined between the middle plate and the rubber membrane, and constructed to allow a pressure adjusting mechanism to adjust the pressure of the space portion, and is set in the form that a bottom surface portion of the rubber membrane holds a back of a work piece to allow a surface of the work piece to be positioned against a grinding cloth on a platform for sliding contact to carry out polishing, wherein at least the bottom surface portion of the middle plate, as a whole, is not set in contact engagement and forms a gap between the middle plate and the rubber membrane. Therefore, the present invention provides a grinding head that, for grinding heads of rubber chuck, can apply a uniform grinding load to the whole work piece without being affected by the rigidity and flatness of the middle plate.

Description

200922744 IX. Description of the Invention: [Technical Field] The present invention relates to a polishing head for maintaining work when polishing a surface of a workpiece, and a polishing apparatus having the same, particularly for the _ holding workpiece A polishing head for a rubber film, and a polishing device having the polishing head. [Prior Art] C) As a device for polishing the surface of a workpiece such as a crucible wafer, there is a single-sided single-side polishing device for separately researching a workpiece, and a double-side polishing device for simultaneously polishing the surface of the workpiece. A general single-side polishing apparatus, for example, as shown in Fig. 9, is composed of a stage 93 to which a polishing cloth 94 is attached, an abrasive supply device 96, a polishing head, and the like. In such a polishing apparatus 91, the workpiece W is first held by the polishing head 92, and then the abrasive 9 5 is supplied from the abrasive supply mechanism 96 to the polishing 94, and the stage 9 3 and the polishing head 9 2 are respectively rotated to make the workpiece The surface of W is in frictional contact (sliding contact) with the polishing cloth 94 to perform polishing. 〇 As a method of holding the workpiece to the polishing head, there is a method of attaching a workpiece to a flat circular plate by an adhesive such as wax. Further, as a holding method for improving the flatness of the entire work piece, a rubber film is used as the workpiece holding portion, and a pressurized fluid of air is introduced into the back surface of the rubber film to expand the rubber film with a uniform pressure, and the workpiece is moved. Pressing the polishing cloth, that is, the rubber chuck method (for example, refer to Japanese Patent Laid-Open Publication No. Hei 5 - 6 9 3 1 0, Special Opening 2 0 0 5 - 3 1 3 3 1 3) Double has 92 cloth dials

200922744 A configuration example of a polishing head of the prior rubber chuck type is shown in Fig. 8(a), and an enlarged view of the peripheral portion of the polishing head is shown in (b). The focus of the polishing head 7 1 is composed of a rubber film 73 fixed by a substantially disk-shaped intermediate plate 7 2 fitted to the intermediate plate 72. The rubber film 73 is supported by the peripheral portion 7 2 c of the top surface of the plate, the side surface portion 7 2 b, and the peripheral portion of the bottom surface. In the bottom surface portion 72a of the intermediate plate, the peripheral protruding portion 7 2d is formed between the rubber film 73 and the center of the space portion intermediate plate 72, and is provided with a through hole 7 that communicates with the adjustment of the pressure adjusting mechanism 75. The pressure of the pressurized fluid adjusting space portion 74 is supplied to the pressure adjusting mechanism 75. Further, a pressing device (not shown) that presses the intermediate plate 72 in the direction of 94 is also provided. In addition, as a polishing head having a structure in which the pressure is applied to the rubber film, a mechanism for uniformly applying pressure to the center plate, or A polishing head configured to apply pressure to a retainer ring provided around the holding portion, such as a polishing head, is provided on the bottom surface portion of the rubber film 733 to hold the workpiece W and press against the intermediate plate. The workpiece W is slid over the polishing cloth 94 that has been attached to the top surface of the platform 93, and the polishing head can be obtained by the polishing head of the rubber chuck type. However, in particular, there is a problem that grinding and sag occurs, and there is a need to improve the uniformity of the grinding. The ground map is shown in Fig. 8, and is formed 74 by the portion 72a. In the case of pressure, etc., it is also reported as a condition. , sweat through the moving contact. The present invention is developed in view of such a problem, and the main object thereof is to provide a polishing head for a rubber chuck-type polishing head that is not affected by the intermediate plate. The rigidity and flatness influence the uniform grinding load on the workpiece.

The present invention has been made to solve the above problems, and provides a polishing head comprising at least a substantially disk-shaped intermediate plate and a rubber film covering at least a bottom surface portion and a side surface portion of the intermediate plate. The intermediate plate and a space portion surrounded by the rubber film constitute a pressure adjusting mechanism for changing a pressure of the space portion, and a back surface of the working member is held on a bottom surface portion of the rubber film to make a surface of the working member A polishing head in which a polishing cloth attached to a platform is slidably contacted to perform polishing is characterized in that the intermediate plate and the rubber film have a gap in contact with at least a bottom surface portion of the intermediate plate. If the working piece is polished by using a polishing head having a gap between the upper plate and the rubber film on the bottom plate portion of the intermediate plate and having no gap therebetween, the bottom plate portion of the intermediate plate and the rubber film have a gap therebetween. Affected by the rigidity and flatness of the middle plate, a uniform grinding load can be applied to the entire workpiece to grind the workpiece. As a result, the work piece is comprehensive, particularly in the outer periphery, and can be polished with high flatness. At this time, the gap between the bottom surface portion of the intermediate plate and the rubber film is preferably less than 1 m m . Thus, if the gap between the bottom surface portion of the intermediate plate and the rubber film is less than 1 mm, the pressure in the space portion can be made more stable, and the grinding of the workpiece can be performed in this state. Further, it is preferable that the intermediate plate and the rubber film have a gap even if the entire side surface of the intermediate plate is not in contact with each other.

In this way, if the middle plate and the rubber film have a gap even if the entire side surface portion of the intermediate plate does not contact, even if the side surface portion is not in contact, the rigidity and shape of the side surface portion of the intermediate plate can be further reduced for the rubber. The influence of the film, therefore, can be more effectively performed by pressing the back surface of the workpiece with a uniform polishing load. As a result, the flatness of the surface of the workpiece can be more effectively maintained to perform polishing. Further, among the rubber films, the inner diameter of the portion covering the side surface portion of the intermediate plate is preferably larger than the flatness securing region of the workpiece. Thus, in the rubber film, the inner diameter of the portion of the side surface portion covering the intermediate plate is larger than the flatness securing region of the workpiece, and the rigidity of the portion of the rubber film covering the side surface portion of the intermediate plate can be reduced for the rubber film. The work piece maintains the influence of the surface to perform the grinding, and the grinding amount uniformity can be more effectively improved to grind the workpiece. Further, the rubber film may have a gasket on the workpiece holding surface, and in this case, the diameter of the gasket is preferably larger than the workpiece. In this way, even if the spacer is provided to the polishing head reliably and the occurrence of scratches or the like on the back surface is prevented, if the diameter of the spacer is made larger than the workpiece, the expansion of the rubber film by the spacer can be reduced. The limitation on the work piece, so that the load can be more evenly pressed to press against the work piece. Furthermore, the present invention provides a polishing apparatus for polishing workpieces 8

200922744 The grinding device used in the surface is characterized in that at least: a grinding j is attached to a platform; an abrasive supply mechanism for supplying the polishing cloth; and a polishing head for maintaining the above work The polishing head of the present invention is described. As described above, by using the polishing apparatus including the polishing head of the present invention, the workpiece can be polished, and a uniform grinding weight can be applied to the entire workpiece to polish the workpiece. As a result, the work piece is comprehensive, and in particular, the polishing can be performed while maintaining high flatness. If the grinding head of the present invention is used for the grinding of the workpiece, the surface of the workpiece is uniformly applied with a uniform pressing force for the grinding. The knot can improve the uniform grinding amount uniformity of the working piece, and the working surface of the grinding is flat. [Embodiment] Hereinafter, the present invention will be described in more detail. As described above, the holder is held by the rubber chuck type, and when the surface of the workpiece is ground, the surface of the workpiece after grinding has a higher level of requirements. Previously, especially in the outer peripheral portion, there is grinding. Problems such as sag. In order to solve such a problem, the inventors conducted experiments and reviews in which the inventors found the following. That is, as shown in Fig. 8, in the bottom surface portion 72a of the intermediate plate 72, if there is a portion (72) with the rubber film 73, even if the projection portion 72d and the rubber film are clothed, the agent is poured upward. The periphery of the Netherlands can be fruitful, and the work of the piece can happen frankly as the first contact 73

200922744 Next, when the workpiece is polished, the workpiece is freely pressed by the pressurized fluid, and when the entire head of the polishing head 7 1 is pressed against the entire head, if the intermediate plate is pressed in the direction of 94, the operation of the rubber film 7 3 The holding surface of the member, the rigidity of the meeting plate 72, the influence of the bottom surface portion 72a (the bottom surface of the protruding portion 72d), etc., cause the shape and the pressing force to become uneven, so that the workpiece holding surface of the rubber film 7 3 is polished. The work piece W. In particular, in the case where the outer side of the workpiece holding surface of the rubber film 73 is retained, and the retaining head of the side structure of the working piece W is held by the retaining ring, since the working piece W is held at 73 Since the bottom portion is almost the outermost peripheral portion, the rubber port is greatly affected by the protruding portion 72d formed at the peripheral portion of the bottom surface portion 72a of the intermediate plate. Further, even if the work piece W is not directly under the contact portion of the protrusion 72d of the rubber film 73 and the middle plate as in the front; while being held on the inner side, the work piece of the rubber film 73 is used to secure the rubber film 73 and the middle plate. The presence of the contact portion of the protruding portion 72d, but the distribution, etc., somewhat affects. In addition, the inventors of the present invention have found that the pressurized fluid introduction space is required to maintain the shape of the rubber film, and the peripheral portion of the intermediate plate 72 has a structure of the portion 72d. In order to support the rubber film 73, it is actually constructed in this way. In other words, it has been found that the entire rubber film of the bottom surface of the middle plate is brought into contact, and the gap can be solved by providing a gap therebetween. Further, even if such a structure is formed, the rubber film state can be maintained, and the polishing cloth is subjected to The rubber film which is held at the edge of the rubber-like dislocation in the middle of the rubber shape: 73 is the same as the contact part, but is a surface, and measures against the pressure. In the case of the Ministry, the present invention is completed by providing a shape that does not require the body to be in harmony with the shape of the above-mentioned question 10 200922744. Hereinafter, the polishing apparatus of the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto. Fig. 1 is a view showing an example of the polishing head of the present invention (the first polishing head Π has a substantially disk-shaped intermediate plate 12 and a covering; | a rubber film having a small bottom portion 1 2 a and a side surface portion 1 2 b (elasticity) Membrane) When the rubber film 13 is fixed to the peripheral portion 12c of the top surface of the intermediate plate in the peripheral portion 12c of the top surface of the intermediate plate, it is followed by an adhesive or the like, and the backing plate 18 is used. In this case, the intermediate plate 12 has at least the bottom surface portion 1 not in contact with the rubber film 13 and has a gap of 14 a. In the preparation of the rubber film 13, the rubber can be formed by a conventional method. The thickness of the film is not particularly limited, and may be selected to be as thick as about 1 mm as appropriate. Thus, between the intermediate plate 12 and the rubber film 13, at least between the face 1 2 a and the rubber film 13 is formed. The space portion 14 is further provided by a pressure adjusting mechanism If which adjusts the pressure in the space portion 14, and is supplied to the through hole 16 of the intermediate plate 12 to supply a pressurized fluid or the like to adjust the pressure of 74. Further, as shown in Fig. 2 The second schematic cross-sectional view of (a) and the second of the polishing head of the present invention indicated by the enlarged view of negative Preferably, the head portion 3 1 is formed such that the entire side surface portion 1 2 b of the panel is also in contact with the film 13 and has a gap 1 4 b. At this time, the peripheral portion 12c of the top surface of the rubber film 13 is fixed. At this time, the grinding head and the state can also be used. This: anti-12 to 13 ° plate 12 〇 例如 For example, only screws etc. to the overall shape of 2a such a film 13 degrees, for example, the bottom of the middle plate is used; By grinding from the space section 2 (b), the grinding is not in contact with the rubber.

200922744 to form a rubber film. Further, even if the entire side surface portion of the intermediate plate is not in contact with the rubber film 13 and has the gap 14b as shown in Fig. 2, there is no gap between the side surface portion 1 2b and the rubber film 13 and the two are in contact with each other. It is also preferred that the two are not fixed by the following. Further, a lining may be attached to the workpiece holding surface of the rubber film 13 to more reliably hold the workpiece W. The spacer 17 includes a moisture patch W, and the workpiece holding surface 17 for holding the workpiece W to the rubber film 13 can be, for example, a foamed polyurethane. The spacer 17 is provided with water, and the working member W can be confirmed by the surface tension of the water contained in the spacer 17. Further, the polishing heads 1 1 and 3 1 are provided with means for pressing against the intermediate plate 1 2 (or 11 or 31 as a whole) (not shown). With the polishing heads 11 and 31 thus configured, the intermediate plate 12 is pressed against the polishing cloth 22 attached to the stage 21 by a resisting device (not shown), and the workpiece W is brought into sliding contact with the polishing cloth 2 2 . Grind the surface. This intermediate plate pressing device is preferably pressed against the intermediate plate with a uniform pressure. Further, as in the first aspect shown in Fig. 10 (an example of the case of the polishing head, the polishing heads 11 and 31 may be provided with a buckle 19 which is along the outer peripheral portion of the bottom surface portion of the film 13 and can be combined with the rubber film 1 The working piece of 3 is interlocked or independently pressed against the abrasive cloth 22. The retaining ring 19 can have an inner side for holding the edge of the working piece W and a guide ring 19 The outer side of a is used to trim the middle plate of the polishing cloth 2 2 12b, and the pad 17 is attached to work. The lining is kept in the direction of the plate pressing in the grinding head to maintain the rubber surface of the workpiece. The face is, for example, .19a; the trim 12 200922744 ring 19b.

The distance between the bottom surface portion 1 2 a of the intermediate plate and the gap 1 4 a between the rubber film 13 is preferably a sufficient distance from the bottom surface portion 12a of the intermediate plate and the rubber film 13 during the polishing, but the upper limit is It is preferably less than 1 mm. If the distance is set to less than 1 mm, the pressure of the space portion 14 can be more easily controlled to be stable and uniform. Further, in the case of the second aspect shown in Fig. 2, the distance between the bottom surface portion 1 2 a of the intermediate plate and the gap 1 4 a between the rubber films 13 is also the same, but the side portion of the intermediate plate The distance between the gap 1 b of the 1 2 b and the rubber film 1 3 is not particularly limited. However, it is preferable that the shape of the rubber film 13 is not unstable. For example, it is preferably about 2 mm or less. When the polishing heads 1 1 and 31 are formed as described above, the workpiece W can adjust the shape and pressure distribution of the rubber film 13 by the pressure of the space portion 14 because the bottom surface portion 1 2 a of the intermediate plate and the rubber film 1 Since the contact is not made, the influence of the rigidity, shape, and the like of the intermediate plate is not transmitted to the rubber film 13, and the workpiece W can be polished by a uniform polishing pressure. Further, according to the second aspect described above, when the polishing head 31 is configured such that the side surface portion 1 2b of the intermediate plate does not contact the rubber film 13, not only the bottom surface portion 1 2 a of the intermediate plate can be prevented from being applied to the rubber film 1 The influence of 3 can also prevent the influence of the side portion 1 2 c on the rubber film 13 . In the present invention, when the workpiece W is held at a slight extent of the bottom surface portion of the rubber film 13, for example, a retaining ring 19 for holding the edge portion of the workpiece W is disposed on the working member of the rubber film 13 When the workpiece W is held on the outer side of the holding surface and the workpiece W is held slightly in the bottom surface portion of the rubber film 13, as in the prior art, the uniformity of the grinding amount is improved due to the absence of the contact portion between the bottom surface portion 12a of the intermediate plate 13 and the rubber film 13 The effect is particularly high. However, the present invention is not limited thereto, and even if the outer diameter of the workpiece is held inside the outer peripheral portion of the rubber film 13, the former bottom plate portion 12a of the intermediate plate and the rubber film 13 can be completely eliminated. The contact portion causes an influence on the pressure distribution generated by the workpiece holding surface of the rubber film 13, so that the polishing amount uniformity is improved as compared with the prior art. However, although the influence of the rigidity and shape of the bottom surface portion 1 2 a of the intermediate plate on the workpiece holding surface of the rubber film 13 can be completely eliminated by the present invention, when the entire bottom surface portion of the rubber film 13 is held, for example, The retaining ring 19 for holding the edge portion of the work piece W is disposed outside the work piece holding surface of the rubber film 13, and the work piece W is held at a slight entirety of the bottom surface portion of the rubber ring 13, the rubber film In the case of the portion of the side surface portion 1 2b of the intermediate plate (hereinafter sometimes referred to as a rubber film side portion), the influence on the workpiece holding surface of the rubber film 13 remains. The influence of the rigidity of the side portion of the rubber film is slight compared with the influence of the intermediate plate 12, but it is preferable to further improve the uniformity of the grinding amount of the workpiece W to minimize the influence thereof. U The enlarged view of the peripheral portion of the polishing head for reducing the influence of the side portion of the rubber film is shown in Fig. 4. (a) is the first aspect described above, and (b) is the second aspect. As shown in Fig. 4 (a) and (b), among the rubber film 13, the portion (the rubber film side portion) 1 3 b covering the side surface portion 1 2 b of the intermediate plate is larger than the outer diameter of the workpiece W. Preferably. However, for example, a buckle for holding the edge portion of the work piece W is disposed outside the work piece holding surface of the rubber film 13, and the work piece W is held by the entire bottom portion of the rubber film 13 At the time, the size of the buckle is also determined in advance, and the 14 200922744 inner diameter of the rubber film side portion 1 3 b is hard to be larger than the outer diameter of the workpiece W. At this time, the inner diameter of the rubber film side portion 1 3 b may be at least larger than the flatness securing region of the work piece. The flatness assurance area of the work piece is the area in which the work piece is comprehensive, and the predetermined flatness is ensured, depending on the specification, for example, the case of a single crystal wafer having a diameter of 300 mm, usually about 1 to 2 mm at the outermost circumference. Excluded areas.

With respect to the workpiece W, by designing the intermediate plate 1 2 and the rubber film 13 in this way, it is possible to reduce the influence of the rigidity of the rubber film side portion 13 b on the workpiece holding surface of the rubber film 13 to be ground. The workpiece W is polished by increasing the amount of grinding uniformity. Further, as described above, in order to hold the workpiece W on the workpiece holding surface of the rubber film 13, the spacer 17 is attached to the bottom surface of the rubber film 13, but as shown in Fig. 1, the spacer 17 The diameter is preferably larger than the diameter of the workpiece W. Further, Fig. 1(a) shows the first aspect, and Fig. 1(b) shows the second aspect. Thus, the influence on the polishing pressure and the polishing shape caused by the expansion of the rubber film 13 itself by the gasket 17 caused by the gasket 17 at the subsequent interface of the gasket 17 and the rubber film 13 can be reduced. However, of course, the diameter of the spacer 17 must be equal to or smaller than the bottom surface portion of the rubber film 13 to which the gasket 17 is to be attached. In particular, the retaining ring for holding the edge portion of the work piece W is disposed on the outer side of the work piece holding surface of the rubber film 13, and the work piece W is held at a slight entirety of the bottom surface portion of the rubber film 13 The size of the pad cannot be increased to the size of the rubber film 13. For example, as the workpiece W, when the wafer having a diameter of 300 mm is polished, the inner diameter of the buckle is about 312 mm, and the diameter of the bottom portion of the rubber film 13 is set to 301.5 mm, which is 15 200922744. The diameter of the gasket is 3 0 1 . 5 mm or less. However, even if it is a small amount, by making the diameter of the lining 17 larger than the diameter of the work piece W, the uniformity of the grinding amount of the work piece W can be more effectively improved. Fig. 3 is a view showing the outline of a polishing apparatus 6 1 including the above-described polishing head 11. In addition to the polishing head U, the polishing apparatus 61 includes a polishing cloth 22 attached to the stage 21 and an abrasive supply mechanism 66 for supplying the polishing agent 65 to the polishing cloth 22.

When the workpiece W is polished by the polishing device 61, first, the workpiece W is held by the rubber film 13. Further, when the spacer is attached to the rubber film 13, the workpiece W is attached to the water-containing spacer 17 and the back surface of the workpiece W is held by the rubber film 13. Further, when the buckle is disposed around the rubber film 13, the edge portion of the workpiece W is held by the buckle. Then, the polishing agent 6 6 is supplied from the polishing agent supply unit 6 6 to the polishing cloth 2 2, and the workpiece W and the polishing cloth 2 2 are slid while rotating the polishing head 1 1 and the stage 2 1 in a predetermined direction. contact. Then, the workpiece W held by the rubber film 13 can be pressed against the polishing cloth 22 on the stage 21 by a predetermined pressing force while rotating, and the surface of the workpiece W can be polished. When the workpiece W is polished by the polishing apparatus 61 having such a polishing head 11, the shape and pressure distribution of the rubber film 13 can be adjusted by the pressure of the space portion 14, because the bottom surface portion 12a of the intermediate plate and the rubber The film 13 is not in contact, and the influence of the rigidity, shape, and the like of the intermediate plate is not transmitted to the rubber film 13, and the workpiece W can be polished with a uniform polishing pressure. Further, even the polishing head 1 1 in Fig. 3 is shown as Fig. 2

200922744 The grinding head 31 can also achieve the same effect. Hereinafter, an embodiment of the present invention and a comparative example (Example 1) will be described. The polishing head 1 having the configuration shown in Fig. 1 is produced as follows: The intermediate plate 12 having an outer diameter of 298 mm has a thickness of 1 mm and an outer diameter thereof. It is a rubber film 13 of 300 mm, and is sandwiched by a backing plate 18, and the wire is fixed, and the space between the bottom surface portion 1 2 a of the intermediate plate and the rubber film 13 is 0.5 mm. Further, a spacer 17 having a diameter is attached to the bottom surface of the rubber film 13, and a polishing apparatus having the inner diameter of 302 mm and having the polishing head 1 1 as described above is disposed around the rubber film 13, and the diameter is 3, for example, Grinding of a single crystal crushing workpiece W of 0 0 mm and a thickness of 7 7 5 ym. Further, the single crystal germanium wafer used was polished on both sides of the wafer, and the edge portion was also polished. Further, in the case where the platform 2 1 has a diameter of 800 mm, the polishing cloth 22 is used as a normal user. At the time of grinding, an abrasive solution containing a phthalic acid gel (c ο 11 〇ida 1 ) was used, and the polishing head 1 1 and the stage 2 1 were rotated at 4 2 rpm, respectively. The grinding load (pressure resistance) of the workpiece W was measured. In the case where the space name pressure is 28, 29, or 30 kPa, two pieces are separately ground under each polishing load. The polishing time is set to 80 seconds. The workpiece W thus polished is evaluated for its uniformity. The uniformity of the amount of polishing is a flat tester, and the thickness of the workpiece before and after the flat grinding is measured at the outermost peripheral portion of the 2 mm-wide bottom portion by the use of a screw gap of 14a 2 9 8 mm. Silica ) 44 rpm P 14

200922744 The flatness guarantee area of the field is obtained by taking the difference in the amount of grinding. The uniformity of the grinding amount (%) = (the maximum amount of grinding in the plane - the small amount of grinding in the plane) / the number of the average grinding amount in the plane Said. As a result, the uniformity of the grinding amount of the obtained work piece is shown in the middle. A uniformity of the grinding amount of about 2 5 to 30% can be obtained, and the amount of grinding is uniform. (Example 2) The polishing head 31 shown in Fig. 2 is the same as that of the first embodiment. However, the intermediate plate 12 has an outer diameter of 296 mm, and the side surface portion 12b of the intermediate plate has a gap 1 between the adhesive films 13 4b is made to 1 mm. The polishing head 31 was used to polish a single crystal circle in the same manner as in the first embodiment. As a result, the uniformity of the grinding amount of the obtained work piece is shown in the middle. A uniformity of the amount of grinding of about 15 to 25% was obtained, and the uniformity of the amount of grinding was higher than that of Example 1.比较 (Comparative Example) The polishing of the single crystal germanium wafer was carried out in the same manner as in Example 1 using the conventional polishing head 711 shown in Fig. 8. As a result, the uniformity of the grinding amount of the obtained work piece is shown in the middle. The uniformity of the grinding amount is discretely uneven, about 50 to 80%, which is worse than the actual ones and two. The fifth best example of the study is the same as that of the oak cut crystal 5Fig. 18 Example 18 200922744 According to the above results, the examples 1 and 2 having the structure of the polishing head of the present invention, and the conventional grinding In comparison with the case of the head, the amount of grinding of the workpiece is improved, and the effect of the present invention is clearly obtained. (Example 3)

Similarly to the above-described second embodiment, a single crystal germanium wafer having a diameter of 300 mm is used as the workpiece W, but the polishing head 31 having the inner diameter of the rubber film 13 b is changed in the range of 2 9 6.9 to 299.5 mm. The grinding load was 3 OkPa, and one piece of the workpiece was ground. Further, since the thickness of the rubber film was 1 mm, the outer diameter of the side portion of the rubber film and the outer diameter of the bottom portion of the rubber film were 298.9 to 301.5 mm. Further, the flatness securing area of the work piece W is 298 mm in diameter when the outermost peripheral portion of the work piece is 1 mm wide, and 296 mm in diameter except when the outermost peripheral portion of the work piece is 2 mm wide. As a result, the uniformity of the grinding amount of the obtained work piece is shown in Fig. 6. This shows that the larger the inner diameter of the rubber film side portion 13b, the more the polishing amount uniformity tends to be increased. (Example 4) As in the above-described Example 2, a single crystal germanium wafer having a diameter of 300 mm was used as the workpiece W, but the inner diameter of the rubber film 13b was 299.5 mm, the polishing load was 30 kPa, and the gasket 17 was The outer diameter is varied within a range of 298 to 300.4 mm, and one piece of the workpiece is ground. As a result, the uniformity of the grinding amount of the obtained work piece is shown in Fig. 7 19 200922744. When the outer diameter of the lining 17 is larger than the diameter of the workpiece W by 300 mm, the uniformity of the amount of grinding is further enhanced. The present invention is not limited to the above-described embodiments, and the above-described embodiments are merely illustrative, and those having the same constitutional principles as those described in the scope of the present invention can achieve the same effects and are included in the present invention. Within the technical scope of the invention. For example, the polishing head of the present invention is not limited to the ones shown in Figs. 1 and 2, and for example, as long as the entire bottom surface portion of the intermediate plate is not in contact with the rubber film, the shape of the other polishing head can be appropriately designed. Wait. Further, the configuration of the polishing apparatus is not limited to that shown in Fig. 3, and may be, for example, a polishing apparatus including a plurality of polishing heads of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a first embodiment of a polishing head according to the present invention, wherein (a) is a schematic cross-sectional view showing the entire polishing head, and (b) is an enlarged view showing a peripheral portion.

Fig. 2 is a schematic cross-sectional view showing a second aspect of the polishing head of the present invention, wherein (a) is a schematic cross-sectional view showing the entire polishing head, and (b) is an enlarged view showing a peripheral portion. Fig. 3 is a schematic block diagram showing an example of a polishing apparatus including the polishing head of the present invention. Fig. 4 is an explanatory view showing the positional relationship between the portion (the rubber film side portion) of the side surface portion of the covered intermediate plate and the outermost peripheral portion of the workpiece among the rubber films. 20 200922744 Fig. 5 is a graph showing the uniformity of the polishing amount of the workpiece after polishing in Examples 1, 2 and Comparative Examples. Fig. 6 is a graph showing the uniformity of the polishing amount of the workpiece when the inner diameter of the portion (the rubber film side portion) of the side surface portion of the coated intermediate plate among the rubber films is changed. Fig. 7 is a graph showing the uniformity of the grinding amount of the workpiece when the outer diameter of the gasket is changed.

Fig. 8 is a schematic cross-sectional view showing the structure of a polishing head of a conventional rubber collet type, wherein (a) is a schematic cross-sectional view showing the entire polishing head, and (b) is an enlarged view showing a peripheral portion. Fig. 9 is a schematic configuration diagram showing an example of a single-sided polishing apparatus. Fig. 10 is a schematic block diagram showing an example of a case where the polishing head of the present invention is provided with a buckle. Fig. 1 is an explanatory view showing the positional relationship between the workpiece, the spacer, and the rubber film in the polishing head of the present invention.

12: intermediate plate 12b: side portion 1 3 : rubber film 14: space portion [description of main components] 11: polishing head 12a: bottom portion 1 2 c: peripheral portion 1 3 b : rubber film side portion 14a: gap 14b : Clearance 1 5 : Pressure adjustment mechanism 1 6 : Through hole 21 200922744

18 : Backing plate 17 : Lining 19 : Buckle 19a : Guide ring 19 b : Dressing ring 21 : Platform 22 : Grinding cloth 31 : Grinding head 61 : Grinding device 65 : Abrasive 66 : Abrasive supply mechanism 71 : Grinding head 72 : Middle plate 72a: bottom surface portion 72b: side surface portion 72c • peripheral portion 72d: protruding portion 73: rubber film 74: space portion 75: pressure adjusting mechanism 76: through hole 77: gasket 91: polishing device 92: polishing head 93: Platform 94: Abrasive cloth 95: Abrasive 96: Abrasive supply mechanism W: Working piece 22

Claims (1)

200922744 X. Patent Application Range: 1. A polishing head comprising: a middle plate comprising at least a slightly disc-shaped plate, and a rubber film covering at least a bottom surface portion and a side surface portion of the plate, having the middle plate And a space portion surrounded by the rubber film, the pressure adjusting mechanism is configured to change the pressure of the space portion, and the back surface of the workpiece is held on the bottom surface portion of the rubber film, so that the surface of the workpiece is attached to A polishing head in which a polishing cloth on a platform is slidably contacted to perform polishing is characterized in that the intermediate plate and the rubber film have a gap in contact with at least a bottom surface portion of the intermediate plate. 2. The polishing head according to claim 1, wherein a gap between the bottom surface of the intermediate plate and the rubber film is less than 1 mm. 3. The polishing head according to claim 1, wherein the intermediate plate and the rubber film have a gap even if they are not in contact with the entire side surface portion of the intermediate plate. 4. The polishing head according to claim 2, wherein the intermediate plate and the rubber film have a gap even if the entire side surface portion of the intermediate plate is not in contact with each other. 5. The polishing head according to claim 1, wherein among the rubber 23 200922744 film, an inner diameter of a portion covering a side surface portion of the intermediate plate is larger than a flatness securing region of the workpiece. 6. The polishing head according to claim 2, wherein an inner diameter of a portion of the rubber film covering a side surface portion of the intermediate plate is larger than a flatness securing region of the workpiece. The polishing head according to claim 3, wherein an inner diameter of a portion of the rubber film covering the side surface portion of the intermediate plate is larger than a flatness securing region of the workpiece. 8. The polishing head according to claim 4, wherein an inner diameter of a portion of the rubber film covering the side surface portion of the intermediate plate is larger than a flatness securing region of the workpiece. 9. The polishing head according to any one of claims 1 to 8, wherein the rubber film is provided with a gasket on the workpiece holding surface. 10. The polishing head of claim 9, wherein the liner has a diameter greater than the workpiece. 11. A polishing apparatus for use in polishing a surface of a workpiece, characterized in that it has at least: 24 200922744 a polishing cloth attached to a platform; and an abrasive supply mechanism for supplying the abrasive And a polishing head according to any one of claims 1 to 8 wherein the polishing head is used to hold the workpiece. 12. A polishing apparatus for use in polishing a surface of a workpiece, characterized in that it comprises at least: a polishing cloth attached to a platform; and an abrasive supply mechanism for supplying the abrasive to the And a polishing head for holding the working piece, the grinding head according to claim 9 of the patent application. 13. A polishing apparatus for use in polishing a surface of a workpiece, characterized in that it comprises at least: a polishing cloth attached to a platform; and an abrasive supply mechanism for supplying the abrasive to the And a polishing head for holding the working piece, which is the grinding head described in claim 10 of the patent application. 25