JP2009033086A - Retainer ring for cmp (chemical mechanical polishing) apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retainer ring which can minimize the time required for break-in polishing. <P>SOLUTION: A corner part on the inner peripheral side on the side of a pressing surface 8a and a corner part on the outer peripheral side are formed in an R-shape and the pressing surface 8a is graded from the inner peripheral side to the outer peripheral side. Thus, the shape on the side of the pressing surface 8a of the retainer ring 8 becomes a state similar to the shape of the pressing surface side of the retainer ring with which an appropriate polishing result is obtained, and the shape of the side of the pressing surface 8a becomes appropriate from the beginning. As a result, immediately after mounting the retainer ring 8 or just by performing break-in polishing for a short period of time, the appropriate polishing result is obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a CMP (Chemical Mechanical Polishing) apparatus for chemically and mechanically polishing a wafer as an object to be polished, and more particularly to an outer periphery of a wafer disposed (mounted) in a holding head of a CMP apparatus. Retainer ring surrounding

  As the integration and performance of semiconductor devices increase, the dimension in the horizontal direction (on the plane) becomes smaller, and the structure in the vertical direction becomes finer and multilayered. In order to realize such miniaturization and multilayering, a semiconductor substrate such as a silicon substrate needs to have high flatness (flatness). For this reason, it is required to increase the flatness at the stage of the wafer, and a CMP apparatus is known as one that meets such a demand (see, for example, Patent Document 1).

The CMP apparatus includes, for example, a rotatable surface plate, a polishing pad disposed on the surface plate, a holding head that holds the wafer and presses it against the polishing pad, and a slurry supply nozzle. . Further, the holding head includes a retainer ring that surrounds the outer periphery of the wafer, an elastic film that presses the upper surface of the wafer, an air chamber that is surrounded by the elastic film, the retainer ring, and the head body, and the air chamber. An air supply path for supplying pressurized air to the air. The retainer ring surrounds the outer periphery of the wafer to prevent the wafer from jumping out, and presses the polishing surface (surface) of the polishing pad for polishing the wafer to flatten and refine (optimize) the polishing surface. It is.
Japanese Patent Laid-Open No. 11-226865

  By the way, since such a retainer ring presses the polishing pad, the pressing surface of the retainer ring (surface that presses the polishing pad) itself is polished and consumed by the polishing pad. For this reason, the retainer ring must be periodically replaced with a new (manufactured and unused) retainer ring. However, when a new retainer ring is mounted and the wafer is polished, the retainer ring is immediately appropriate ( A good polishing result (polishing performance) was not obtained. In other words, there are problems such as the occurrence of scratches (scratches) and polishing debris on the surface to be polished of the wafer, and the inability to obtain uniform and predetermined surface roughness and flatness (in-plane uniformity). It was. For this reason, when a new retainer ring is mounted, it is necessary to perform break-in polishing before starting to polish a product wafer (wafer produced as a product). That is, a new retainer ring is mounted on a holding head of a CMP apparatus, and tens to hundreds of dummy wafers (break-in wafers) are polished. Then, after confirming that an appropriate polishing result can be obtained, that is, after confirming that a wafer having a predetermined surface roughness and flatness is obtained without scratches or the like, it is necessary to start polishing of the product wafer. However, such break-in polishing requires a lot of time and labor, which has been a factor of reducing the production operation rate of wafers.

  Therefore, an object of the present invention is to provide a retainer ring that can minimize the time required for break-in polishing.

  As a result of investigation and research, the present inventor has a large influence on the polishing surface shape of the retainer ring, and the shape of the retainer ring on the pressing surface side must be appropriate to obtain an appropriate polishing result. I got the conclusion. That is, as a result of comparing and investigating the shape on the pressing surface side of the new retainer ring manufactured in the conventional shape and the retainer ring in which the wafer is actually polished to obtain an appropriate polishing result, there is a difference between the two. Confirmed that there is. Due to this difference, a new retainer ring does not provide an appropriate polishing result immediately. In other words, to obtain an appropriate polishing result immediately with a new retainer ring, it is necessary to eliminate or reduce this difference. I came to the conclusion that there is.

  Accordingly, in order to achieve the above object, the invention according to claim 1 is a CMP apparatus that chemically and mechanically polishes a wafer by pressing the wafer against a polishing pad, and surrounds the outer periphery of the wafer in a ring shape, and the polishing pad. The retainer ring for CMP apparatus that presses the polishing surface of the CMP apparatus, wherein the shape of the pressing surface that presses the polishing surface of the polishing pad is the shape of the pressing surface side of the retainer ring for CMP apparatus that has obtained an appropriate polishing result It is formed based on. Here, an appropriate polishing result means that the surface to be polished of the wafer satisfies a predetermined required specification. Specifically, the surface to be polished of the wafer is free of scratches or polishing scraps of a predetermined size or larger, and the surface to be polished of the wafer satisfies the predetermined surface roughness and flatness over the entire surface and is uniform. Means.

  The invention according to claim 2 is a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad. The CMP apparatus surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad. The retainer ring is characterized in that at least one of a corner portion on the inner peripheral side and a corner portion on the outer peripheral side on the pressing surface side that presses the polishing surface of the polishing pad is formed in a curved surface shape or a tapered shape. And

  According to a third aspect of the present invention, in the retainer ring for a CMP apparatus according to the second aspect, the shape of the corner is set based on a polishing condition for polishing the wafer. Here, the polishing conditions relate to polishing including the type of CMP apparatus, the type and size of the wafer, the type of slurry and polishing pad, the material and size of the retainer ring, the polishing rate (polishing rate), the amount of pressurization, and the like. It is a condition.

  According to a fourth aspect of the present invention, there is provided a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad. The CMP apparatus surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad. In the retainer ring, a pressure surface that presses the polishing surface of the polishing pad is provided with a gradient from the inner peripheral side toward the outer peripheral side.

  According to a fifth aspect of the present invention, in the retainer ring for a CMP apparatus according to the fourth aspect, the gradient direction is set based on a polishing condition for polishing the wafer.

  The invention according to claim 6 is a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad. The CMP apparatus surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad. A retainer ring, wherein a concave relief groove is formed on a pressing surface side that presses the polishing surface of the polishing pad, and an outer corner portion of the relief groove is formed in a tapered shape or a curved surface. .

  According to a seventh aspect of the present invention, in the retainer ring for a CMP apparatus according to the sixth aspect, the shape of the outer corner portion is set based on a polishing condition for polishing the wafer.

  According to the first aspect of the present invention, the shape on the pressing surface side of the retainer ring is formed based on the shape on the pressing surface side of the retainer ring from which an appropriate polishing result is obtained. Time can be minimized. That is, since the shape of the retainer ring on the pressing surface side is formed on the basis of the retainer ring that has no scratch or the like and obtained an appropriate polishing result, the shape of the retainer ring on the pressing surface side is in an appropriate state from the beginning. ing. For this reason, it is possible to obtain an appropriate polishing result immediately after mounting the retainer ring or only by performing a brief break-in polishing.

  According to the second aspect of the present invention, at least one of the inner peripheral corner and the outer peripheral corner on the pressing surface side of the retainer ring is formed in a curved surface shape or a tapered shape. This is based on the fact that at least one of the inner peripheral corner and the outer peripheral corner on the pressing surface side of the retainer ring from which an appropriate polishing result is obtained has a curved surface shape or a tapered shape. . And since it forms in such a shape, the shape of the corner | angular part by the side of the pressing surface of a retainer ring will be in an appropriate state from the beginning, and it will become possible to minimize the time required for break-in grinding.

  According to the third aspect of the present invention, the shape of the corner is set based on the polishing conditions for polishing the wafer. This is based on the fact that the shape of the corner on the pressing surface side of the retainer ring from which an appropriate polishing result was obtained differs depending on the polishing conditions. And, by setting the shape of the corner of the retainer ring used under a certain polishing condition to be the same as the shape of the corner of the retainer ring that was used under the same polishing condition and obtained an appropriate polishing result, The shape is appropriate from the beginning. As a result, it is possible to minimize the time required for break-in polishing.

  According to the fourth aspect of the present invention, the gradient is provided on the pressing surface of the retainer ring from the inner peripheral side toward the outer peripheral side. This is based on the fact that the pressing surface of the retainer ring that has obtained an appropriate polishing result has a gradient, and the pressing surface of the retainer ring is in an appropriate state from the beginning by providing the gradient. Thus, the time required for break-in polishing can be minimized.

  According to the invention described in claim 5, the direction of the gradient is set based on the polishing conditions for polishing the wafer. This is based on the fact that the direction of the gradient of the pressing surface of the retainer ring from which an appropriate polishing result was obtained (whether ascending or descending) differs depending on the polishing conditions. And the direction of the gradient of the pressing surface of the retainer ring used under a certain polishing condition is set to be the same as the direction of the gradient of the pressing surface of the retainer ring that was used under the same polishing condition and obtained an appropriate polishing result. Thus, the direction of the gradient of the pressing surface is appropriate from the beginning. As a result, it is possible to minimize the time required for break-in polishing.

  According to the invention described in claim 6, the outer corner portion of the relief groove formed on the pressing surface side of the retainer ring is formed in a tapered shape or a curved surface shape. This is based on the fact that the retainer ring that has an appropriate polishing result and has an escape groove has a tapered or curved outer corner. And since it forms in such a shape, the outer corner | angular part of the escape groove | channel of a retainer ring will be in an appropriate state from the beginning, and it will become possible to suppress the time required for break-in grinding to the minimum.

  According to the seventh aspect of the invention, the shape of the outer corner portion of the escape groove is set based on the polishing conditions for polishing the wafer. This is based on the fact that the shape of the outer corner portion of the escape groove differs depending on the polishing conditions when the retainer ring has an appropriate polishing result and has a relief groove. The shape of the outer corner of the retainer ring relief groove used under certain polishing conditions is set to be the same as the shape of the outer corner of the retainer ring relief groove obtained under the same polishing conditions and with proper polishing results. By doing so, the shape of the outer corner portion of the escape groove becomes appropriate from the beginning. As a result, it is possible to minimize the time required for break-in polishing.

  As described above, it is possible to effectively improve the production operating rate of the CMP apparatus as a result of minimizing the time required for break-in polishing. In addition, since the time required for break-in polishing is minimized, the amount of polishing debris due to break-in of the dummy wafer is reduced, and the rate of occurrence of scratches and impurity adhesion to the wafer (product wafer) due to the polishing debris is further reduced. To do. As a result, the production quality of the wafer is improved and stabilized, and the productivity is further improved by reducing defective products.

  The present invention will be described below based on the illustrated embodiments.

(Embodiment 1)
FIG. 1 is a front view showing a schematic configuration of a CMP apparatus 1 according to this embodiment. The CMP apparatus 1 has the same configuration as a CMP apparatus that is widely used except for a retainer ring (CMP apparatus retainer ring) 8 that will be described later. A plate 2, a polishing pad 3 (such as a cloth) disposed on the surface plate 2, a holding head 4, a slurry supply nozzle 5 and a dresser 6 (shaping means) are provided, and the wafer W is chemically and mechanically attached. It is to be polished.

  The holding head 4 holds the wafer W and presses the surface to be polished W1 against the polishing pad 3. The holding head 4 can move on the polishing pad 3 while rotating (spinning). As shown in FIG. 2, the holding head 4 includes a head main body 7, a retainer ring 8 disposed at a lower portion of the head main body 7, and is positioned in the retainer ring 8 to press the upper surface W <b> 2 of the wafer W. And an elastic film 9. Then, pressure air is supplied to the air chamber 10 surrounded by the head body 7, the retainer ring 8, and the elastic film 9, and the wafer W is pressed against the polishing pad 3 through the elastic film 9.

  The retainer ring 8 surrounds the outer periphery of the wafer W, prevents the wafer W from jumping out of the holding head 4, and also provides a polishing surface 3a of the polishing pad 3 for polishing the wafer W (a surface in surface contact with the polishing target surface W1 of the wafer W). ) Is flattened and refined (optimized). That is, the polishing surface 3a of the polishing pad 3 has a low flatness due to the slurry (abrasive) 5a and a rough surface, and the retainer ring 8 increases the flatness of the polishing surface 3a and the surface roughness. Is to make it smaller.

  This retainer ring 8 is made of a PPS (polyphenylene sulfide) material in this embodiment in consideration of chemical resistance, mechanical properties, etc., and has a ring shape as shown in FIG. The cross-sectional shape of the vertical plane that overlaps the center line is a quadrangle. On the side of the pressing surface 8a that presses the polishing surface 3a of the polishing pad 3, a plurality of concave relief grooves 8b are formed for releasing (discharging) polishing debris. In addition, a plurality of screw inserts 8d formed with female screws 8e are inserted on the back surface 8c side of the retainer ring 8 located on the back surface of the pressing surface 8a. That is, the screw insert 8d has a substantially cylindrical shape, a male screw is formed on the outer periphery, and a female screw 8e is formed on the inner periphery. The retainer ring 8 can be attached to the head body 7 (holding head 4) via the screw insert 8d.

  Furthermore, the shape on the pressing surface 8a side is formed based on the shape on the pressing surface side of a retainer ring (hereinafter referred to as “stabilized retaining ring” as appropriate) from which an appropriate polishing result was obtained. Here, the proper polishing result means that the surface to be polished W1 of the wafer W satisfies a predetermined required specification. Specifically, the surface to be polished W1 of the wafer W does not have scratches or polishing scraps of a predetermined size or larger, and the surface W1 to be polished satisfies the predetermined surface roughness and flatness over the entire surface and is uniform. Means that. The stabilized retainer ring is a retainer ring which is used under the same polishing conditions as the present retainer ring 8 and stably obtains an appropriate polishing result. The polishing condition is a CMP apparatus. Conditions relating to polishing, including the type of wafer, the type and size of the wafer, the type of slurry and polishing pad, the material and shape / size of the retainer ring, the polishing rate (polishing rate), and the amount of pressurization.

  That is, in general, in mass production polishing of a wafer, a plurality of wafers are polished mass-produced and continuously under the same polishing conditions, and replaced with a new retainer ring when the retainer ring is consumed. The shape of the retainer ring 8 used on the same polishing conditions on the side of the pressing surface 8a is formed based on the retainer ring that has been used previously and has obtained an appropriate polishing result, that is, the stabilized retainer ring. It is what has been.

  Specifically, it is formed as follows. First, as shown in FIG. 4, the inner peripheral corner and the outer peripheral corner on the pressing surface 8 a side are each formed into an arc R shape (round, curved surface shape) (R processing). Yes. Further, in this embodiment, the size of the inner peripheral side angle R1 is set to a radius of 0.05 mm, and the size of the outer peripheral side angle R2 is set to a radius of 0.10 mm. The reason why it is formed in such a shape is as follows.

  That is, when the inner peripheral corner and the outer peripheral corner of the stabilized retainer ring used under the same polishing conditions as the polishing conditions in which the present retainer ring 8 is used were investigated, each of them was found to have a corner R shape. by. Specifically, the wafer W was polished by attaching to the CMP apparatus 1 a retainer ring in which a corner portion on the inner peripheral side is a right angle (sharp edge) and a minute chamfer is formed on the corner portion on the outer peripheral side. . As a result, at the beginning of polishing (while several hundred wafers W were polished), an appropriate polishing result was not stably obtained, but thereafter an appropriate polishing result was stably obtained. Then, after the time when a stable and proper polishing result is obtained (at this time, this retainer ring becomes the stabilized retainer ring), the corner on the inner peripheral side and the corner on the outer peripheral side on the pressing surface side are investigated. As a result, a result as shown in FIG. 5 was obtained. FIG. 3 shows the time after a stable and proper polishing result was obtained, that is, when 700 wafers were polished, when 1000 wafers were polished, when 3500 wafers were polished, and when 5000 wafers were polished. The result of three-dimensional measurement of the corners on the inner peripheral side and the corners on the outer peripheral side of the measurement locations P1 to P4 shown in (b) is shown. And the numerical value in a figure shows the magnitude | size (radius) of the angle | corner R of a corner | angular part, and shows that a corner | angular part is a right angle in the case of zero value.

  As is apparent from this figure, in the state where an appropriate polishing result is obtained, the corners on the inner and outer peripheral sides are both in the shape of a corner R, and the size does not vary greatly. . This suggests that both the inner and outer corners need to be rounded and have a predetermined size in order to stably obtain an appropriate polishing result. From such investigation results, the inner peripheral corner and the outer peripheral corner of the retainer ring 8 are formed in the same shape as the stabilizing retainer ring. In addition, since an appropriate polishing result was not obtained at the beginning of the above polishing and a lot of conventional break-in polishing was required, the corner portions on the inner and outer peripheral sides were conventionally subjected to break-in polishing as described above. It is considered that an appropriate state is obtained, and then an appropriate polishing result can be stably obtained.

  Here, it is necessary to set the shape of the corners on the inner and outer peripheral sides based on the polishing conditions. In this embodiment, the shape is set as described above. It is necessary to set based on the shape of the inner and outer corners of the stabilizing retainer ring used in the polishing conditions. Therefore, depending on the polishing conditions, it may be necessary to form only one of the corners on the inner peripheral side or the corners on the outer peripheral side into a corner R shape, and the size of the corner R shape varies depending on the polishing conditions.

  Further, as shown in FIG. 4, the pressing surface 8 a of the retainer ring 8 is provided with a gradient from the inner peripheral side toward the outer peripheral side. That is, in this embodiment, the direction of the gradient is set so as to rise upward from the inner peripheral side to the outer peripheral side with the pressing surface 8a facing downward (the polishing pad 3 side). . The height difference D1 between the inner peripheral edge and the outer peripheral edge is set to 0.03 mm. The reason why the pressing surface 8a is formed in such a shape is as follows.

  That is, when the pressing surface of the stabilized retainer ring used under the same polishing conditions as the polishing conditions in which the present retainer ring 8 is used was investigated, the results shown in FIG. 6 were obtained. This figure shows the distance L in the outer peripheral direction with reference to the inner peripheral edge as a zero reference, as shown in FIG. 7, at the measurement points P2 (X direction) and P1 (Y direction) shown in FIG. 3B of the stabilizing retainer ring. It is the result of measuring the relationship between the height D of the pressing surface 8a. As is apparent from this figure, in the stabilized retainer ring of this polishing condition, a gradient in the upward direction is formed from the inner peripheral side to the outer peripheral side, and the height difference between the inner peripheral side peripheral edge and the outer peripheral side peripheral edge It can be seen that D1 is about 0.03 mm. This means that in order to obtain a stable and appropriate polishing result, the pressing surface 8a has an upward gradient from the inner peripheral side to the outer peripheral side, and the height difference D1 requires about 0.03 mm. It suggests. From such investigation results, the pressing surface 8a of the retainer ring 8 is formed in the same shape as the stabilized retainer ring. As in the case of the corners on the inner and outer peripheral sides, conventionally, it is considered that the pressing surface 8a is brought into an appropriate state as described above by break-in polishing, and thereafter an appropriate polishing result can be stably obtained. It is done.

  Here, it is necessary to set the gradient direction and size (height difference D1) of the pressing surface 8a based on the polishing conditions. In this embodiment, the setting is performed as described above. Is different, it is necessary to set based on the direction and magnitude of the gradient of the pressing surface of the stabilizing retainer ring used under the polishing conditions. Therefore, depending on the polishing conditions, as shown in FIG. 8, it may be necessary to form a downward gradient from the inner peripheral side to the outer peripheral side, and the height difference D1 also differs depending on the polishing conditions.

  According to the retainer ring 8 configured as described above, the shape on the pressing surface 8a side is formed based on the shape on the pressing surface side of the stabilized retainer ring under the same polishing conditions as the polishing conditions in which the retainer ring 8 is used. Therefore, the time required for break-in polishing can be minimized. That is, since the shape of the retainer ring 8 on the side of the pressing surface 8a is formed according to the retainer ring that has stably obtained an appropriate polishing result, the shape of the pressing surface 8a side is in an appropriate state from the beginning. . For this reason, it is possible to stably obtain an appropriate polishing result immediately after the retainer ring 8 is mounted on the CMP apparatus 1 or just by performing a brief break-in polishing.

  More specifically, the inner and outer peripheral corners of the retainer ring 8 are formed into an angular R shape following the fact that the inner and outer peripheral corners of the stabilizing retainer ring have an R shape, Its size is set to the same level as the stabilizing retainer ring. For this reason, the shape and size of the corner on the pressing surface 8a side of the retainer ring 8 are in an appropriate state from the beginning, and the time required for break-in polishing can be minimized. Further, following the fact that the pressing surface of the stabilizing retainer ring has a gradient, the pressing surface 8a of the retainer ring 8 is provided with a gradient, and the direction and magnitude of the gradient are the same as those of the stabilizing retainer ring. It is set to be the same or similar. For this reason, the pressing surface 8a of the retainer ring 8 is in an appropriate state from the beginning, and the time required for break-in polishing can be minimized.

(Embodiment 2)
FIG. 9 is a bottom view showing the pressing surface 8a side of the CMP apparatus retainer ring 8 according to this embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be given. Omitted.

  A plurality of escape grooves 8b are formed on the side of the pressing surface 8a of the retainer ring 8 along the entire circumference. As shown in FIG. 10, the escape groove 8 b has a concave cross section and is formed so as to penetrate from the inner peripheral edge to the outer peripheral edge of the retainer ring 8. Further, the outer corner portion 8f of the escape groove 8b, that is, the outer corner portion 8f formed by the upper end portion of the escape groove 8b and the pressing surface 8a in the drawing is formed in a tapered shape as shown in FIG. The reason why the taper is formed in this way is as follows. That is, similarly to the first embodiment, the outer retainer ring (8b) has an outer corner portion (8b) that is used under the same polishing conditions as the polishing conditions in which the retainer ring 8 is used and an appropriate polishing result is obtained ( When 8f) was investigated, the outer corner portion was tapered.

The outer corner portion 8f is formed along the escape groove 8b, and the shape thereof is set based on the polishing conditions for polishing the wafer W. Specifically, in this embodiment, the shape of the outer corner portion 8f is set and formed as follows with respect to the first polishing condition. That is, in the enlarged view of the outer corner portion 8f shown in FIG. 12, the taper angle θ1 is 35 °, the depth F1 from the pressing surface 8a is about 0.25 mm, or the width H1 toward the pressing surface 8a is 0.4 mm. Is set to about. Furthermore, the inner peripheral corner of the retainer ring 8 is set to a substantially right angle (sharp edge), and the outer peripheral corner is an enlarged view shown in FIG. 13 (cross-sectional enlarged view seen from the direction V3-V3 in FIG. In the figure, the taper angle θ2 is set to 35 °, the taper depth F2 from the pressing surface 8a is set to about 0.26 mm, or the taper width H2 toward the pressing surface 8a is set to about 0.36 mm. When the outer corner (8f) and the inner and outer corners of the relief groove (8b) of the stabilizing retainer ring under the first polishing conditions are examined, the following is set. This is because the result was obtained.
Depth F1: 0.27-0.28mm viewed from the inner circumference V1
Depth F1 viewed from the outer peripheral side V2: 0.24 to 0.25 mm
Width H1: 0.37 to 0.38 mm viewed from the inner circumference side V1
Width H1 as viewed from the outer peripheral side V2: 0.34 mm
Taper angle θ1 viewed from the inner peripheral side V1: 36 ° 09 ′ to 36 ° 23 ′
Taper angle θ1 as viewed from the outer peripheral side V2: 35 ° 13 ′ to 36 ° 31 ′
Inner peripheral corner: almost right angle Outer peripheral corner taper angle θ2: 35 ° 45′-35 ° 50 ′
Taper depth F2 at the corner on the outer peripheral side: 0.26 mm
Tapered width H2 at the corner on the outer peripheral side: 0.36 mm

In addition, the shape of the outer corner portion 8f is set and formed as follows with respect to the second polishing condition. That is, the taper angle θ1 is set to 40 °, the depth F1 from the pressing surface 8a is set to about 0.3 mm, or the width H1 toward the pressing surface 8a is set to about 0.4 mm. Further, the inner peripheral side corner of the retainer ring 8 is set at a substantially right angle (sharp edge), and the outer peripheral side corner has a taper angle θ2 of 40 ° and a taper depth F2 from the pressing surface 8a of zero. About 26 mm, or the taper width H2 toward the pressing surface 8a is set to about 0.3 mm. When the outer corner (8f) of the relief groove (8b) and the inner and outer corners of the stabilizing retainer ring in the second polishing condition are examined, the following is set. This is because the result was obtained.
Depth F1 as viewed from the inner circumference V1: 0.30 to 0.33 mm
Depth F1 viewed from the outer peripheral side V2: 0.29 to 0.30 mm
Width H1: 0.37 to 0.38 mm viewed from the inner circumference side V1
Width H1 as viewed from the outer peripheral side V2: 0.35 to 0.36 mm
Taper angle θ1 viewed from the inner peripheral side V1: 39 ° 02 ′ to 40 ° 58 ′
Taper angle θ1 viewed from the outer peripheral side V2: 39 ° 38 ′ to 39 ° 48 ′
Inner peripheral corner: almost right angle Outer peripheral corner taper angle θ2: 39 ° 17 ′ to 40 ° 54 ′
Taper depth F2 at the corner on the outer peripheral side: 0.26 to 0.27 mm
Tapered width H2 at corners on the outer peripheral side: 0.30 to 0.33 mm

  Here, the above-described first and second polishing conditions are merely examples, and the taper angle θ1, the depth F1, the width are based on the stabilized retainer ring as described above, depending on the polishing conditions to be used. H1 or the like may be set. In practice, the taper angle θ1, the depth F1, the width H1, and the like may be set according to the accuracy of processing and the degree of effect. That is, when it is difficult to process the taper angle θ1, the depth F1, the width H1, etc. with high accuracy as described above, or even if it is not formed according to the above numerical values (even if the numerical values are rounded), there is some effect. When obtained, for example, a chamfer with a taper angle θ1 of 45 ° may be formed into the shape of the outer corner portion 8f. In this case, the size is, for example, about C0.3 mm under the first and second polishing conditions.

  Further, like the corners on the inner and outer peripheral sides on the pressing surface 8a side in the first embodiment, the outer corner portion 8f of the relief groove 8b is formed into an arcuate corner R shape (curved surface shape) (R processing). Also good. In this case, the size is, for example, about R0.3 mm under the first and second polishing conditions. Thus, it is not always necessary to match the shape of the outer corner portion (8f) of the stabilizing retainer ring, as long as it is formed based on the shape on the pressing surface side of the stabilizing retainer ring (shape of the outer corner portion). That is, the outer corner portion of the relief groove of the stabilizing retainer ring is not a right angle, but is in a state where the corner has escaped (obtuse angle), and it is assumed that an appropriate polishing result is obtained. Therefore, the outer corner portion 8f of the relief groove 8b of the retainer ring 8 may be formed in a taper shape or a curved surface shape based on the shape of the outer corner portion of the stabilization retainer ring relief groove.

  According to the retainer ring 8 configured as described above, the outer corner portion 8f of the relief groove 8b is formed in a tapered shape in the same manner as the stabilization retainer ring (following the stabilization retainer ring). The outer corner portion 8f of 8b is in an appropriate state from the beginning. In addition, the shape of the outer corner portion (8f) of the relief groove (8b) of the stabilized retainer ring, which is used under the same polishing conditions as the polishing conditions 1 or 2 in which the retainer ring 8 is used, and an appropriate polishing result is obtained. Since they are set to be the same, the shape of the outer corner portion 8f of the relief groove 8b becomes an appropriate shape from the beginning with respect to the polishing condition 1 or 2. Further, the shape of the inner and outer peripheral corners of the retainer ring 8 in which such escape grooves 8b are formed is formed based on the stabilized retainer ring. The shape is in an appropriate state from the beginning. As a result, the time required for break-in polishing can be minimized as in the first embodiment.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the above-described embodiment, the retainer ring 8 is made of PPS. Other engineering plastics such as polyimide) may be used. In the above-described embodiment, the retainer ring 8 has an integral structure (one-layer structure), but may have a two-layer structure. That is, for example, a two-layer retainer ring in which an engineering plastic ring is disposed on the polishing pad 3 side and a stainless steel ring is superimposed thereon may be used. Furthermore, in the first embodiment, the corners on the inner and outer peripheral sides are formed in the corner R shape, but it is needless to say that the effect is exhibited even if the corner portion is not a perfect R shape (arc).

It is a front view which shows schematic structure of the CMP apparatus which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing of the holding head of the CMP apparatus of FIG. It is the front view (a) and bottom view (b) of the retainer ring of the holding head of FIG. It is an enlarged view of the A section of FIG. It is a figure which shows the magnitude | size (radius) of the corner | angular part R of the inner peripheral side by the side of the press surface of the stabilization retainer ring, and the corner | angular part of an outer peripheral side at the time of polishing a predetermined number of wafers. It is the figure (a) which shows the measurement result of the gradient in the measurement location P2 (X direction) of the pressing surface of a stabilization retainer ring, and the figure (b) which shows the measurement result of the gradient in the measurement location P1 (Y direction). It is a figure which shows the measuring method of the result of FIG. It is a figure which shows the case where the downward gradient is formed in the pressing surface of the retainer ring which concerns on Embodiment 1 of this invention toward the outer peripheral side from an inner peripheral side. It is a bottom view which shows the press surface side of the retainer ring for CMP apparatuses which concerns on Embodiment 2 of this invention. FIG. 10 is an enlarged perspective view showing an escape groove of the retainer ring of FIG. 9. FIG. 10 is an enlarged side view showing an escape groove of the retainer ring of FIG. 9. It is an enlarged view which shows the outer corner | angular part of the escape groove of FIG. It is the cross-sectional enlarged view seen from the V3-V3 direction of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CMP apparatus 2 Surface plate 3 Polishing pad 3a Polishing surface 4 Holding head 5 Slurry supply nozzle 5a Slurry 6 Dresser 7 Head body 8 Retainer ring 8a Pressing surface 8b Escape groove 8c Back surface 8d Screw insert 8f Outer corner 9 Elastic body film 10 Air chamber W Wafer W1 Surface to be polished

Claims (7)

In a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad, a retainer ring for the CMP apparatus that surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad,
The shape of the pressing surface side that presses the polishing surface of the polishing pad is formed based on the shape of the pressing surface side of the retainer ring for the CMP apparatus from which an appropriate polishing result was obtained.
A retainer ring for a CMP apparatus. In a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad, a retainer ring for the CMP apparatus that surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad,
At least one of the corner portion on the inner peripheral side and the corner portion on the outer peripheral side on the pressing surface side that presses the polishing surface of the polishing pad is formed in a curved surface shape or a tapered shape,
A retainer ring for a CMP apparatus. Based on polishing conditions for polishing the wafer, the shape of the corner is set,
The retainer ring for a CMP apparatus according to claim 2. In a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad, a retainer ring for the CMP apparatus that surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad,
On the pressing surface that presses the polishing surface of the polishing pad, a gradient is provided from the inner peripheral side toward the outer peripheral side,
A retainer ring for a CMP apparatus. The direction of the gradient is set based on polishing conditions for polishing the wafer,
The retainer ring for a CMP apparatus according to claim 4, wherein In a CMP apparatus for chemically and mechanically polishing a wafer by pressing the wafer against a polishing pad, a retainer ring for the CMP apparatus that surrounds the outer periphery of the wafer in a ring shape and presses the polishing surface of the polishing pad,
A concave relief groove is formed on the pressing surface side that presses the polishing surface of the polishing pad, and an outer corner portion of the relief groove is formed in a taper shape or a curved surface shape,
A retainer ring for a CMP apparatus. Based on polishing conditions for polishing the wafer, the shape of the outer corner is set,
The retainer ring for a CMP apparatus according to claim 6.

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