JP2011031322A - Polishing device and polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the number of chips taken from a wafer and improve yield by preventing the reduction of the polishing rate of the outer circumference of the wafer and allowing the entire wafer to be uniformly polished. <P>SOLUTION: A polishing device includes a carrier for holding the wafer 13 and a retainer ring 14 and a platen 11 on which a polishing pad 12 is stuck. The polishing pad 12 has a step part 20 between a flat part and a protruded part in an area on the surface to allow the outer circumference of the wafer 13 to contact with when brought into press contact with the wafer 13. The step part 20 is flattened through press-contact by the wafer 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing apparatus and a polishing method, and more particularly to a wafer polishing apparatus and a polishing method using a chemical mechanical polishing (CMP) method in a manufacturing process of a semiconductor integrated circuit.

  In recent years, with the miniaturization of semiconductor integrated circuits, a technique for flattening the irregularities on the surface of a wafer has become important. As a method for flattening the unevenness of the surface of the wafer, a chemical mechanical polishing (CMP) method is generally employed in which the wafer is pressed against a polishing pad provided in a polishing apparatus and polished using a slurry. .

  A conventional polishing apparatus will be described with reference to FIGS. 7A and 7B show a cross section of the polishing apparatus according to the first conventional example, FIGS. 8A and 8B show a cross section of the polishing apparatus according to the second conventional example, and FIG. (A) And (b) has shown the cross section of the grinding | polishing apparatus which concerns on a 3rd prior art example. In each drawing, (a) shows a cross section before the wafer is pressed against the polishing pad, and (b) shows the cross section and the press contact after the wafer is pressed against the polishing pad (during polishing). This pressure distribution is shown.

  As shown in FIG. 7A, a polishing pad 102 having a uniform overall thickness is stuck on a flat platen 101, and the side surface and the back surface of the wafer 103 are held on the carrier on the polishing pad 102. A retainer ring 104 is provided. The retainer ring 104 is provided to prevent the wafer 103 from jumping out of the carrier during polishing.

  As shown in FIG. 7B, when the wafer 103 is pressed against the polishing pad 102 by applying pressure from above the wafer 103, the retainer ring 104 also presses against the polishing pad 102. As a result, the polishing pad 102 is elastically deformed. As a result, in the region 105 of 5 mm to 20 mm from the peripheral end surface of the wafer 103 toward the center, the polishing rate increases due to rebound of the elastic deformation of the polishing pad 102.

  Therefore, as shown in FIGS. 8A and 8B, in the polishing pad 102, a strain prevention groove 106 is formed in a region where the retainer ring 104 is in contact with the polishing pad 102, thereby preventing distortion (elastic deformation) of the polishing pad 102. A polishing apparatus that stabilizes the polishing rate is proposed in Patent Document 1 and the like.

  In addition to this, as shown in FIGS. 9A and 9B, an area (pressure zone control area 107) in which pressurization from above the wafer 103 can be divided and controlled into a plurality of zones is provided. A method has been proposed in which the polishing rate is stabilized by lowering the pressure in the region 105 of 5 mm to 20 mm in the center direction from the peripheral end surface of the substrate.

JP 2008-221368 A

  The rebound of the elastic deformation of the polishing pad occurs in the direction of movement of the wafer relative to the polishing pad. In the conventional polishing apparatus, although the distortion prevention groove is formed in the outer peripheral portion of the polishing pad, the distortion prevention groove is not formed in the direction of movement of the wafer. Since it is not formed, it does not have the effect of suppressing fluctuations in the polishing rate due to rebound. Also, if there is an effect, the elastic deformation of the polishing pad due to the retainer ring can be prevented, but the elastic deformation of the polishing pad due to the edge of the wafer is prevented because the edge of the wafer directly presses against the polishing pad. Occur. In other words, providing a strain prevention groove is not an essential solution.

  In recent years, the wafer zone pressurization method has become the mainstream, and further, independent pressurization of the retainer ring is also performed. However, there is a problem that pressure zone control alone cannot sufficiently cope with the outer peripheral portion of the wafer (particularly, a region of about 3 mm from the peripheral end surface of the wafer toward the center). In order to prevent the wafer from popping out, it is necessary to make the pressure of the retainer ring for the polishing pad larger than the zone pressure of the wafer, resulting in a decrease in the polishing rate of the outer peripheral portion of the wafer. Variations in the polishing rate within the plane of the wafer lead to a reduction in the number of chips that can be taken from the wafer. In addition, unstable film remains (when the polishing rate is low) at the outer peripheral portion of the wafer, and particles are generated from this portion, which may affect the yield. This has a larger influence as the subsequent process is performed, and is particularly important in the copper (Cu) -CMP method.

  In view of the above-described conventional problems, the object of the present invention is to increase the number of chips that can be taken from a wafer by preventing the polishing rate of the outer peripheral portion of the wafer from decreasing and enabling the entire wafer to be polished uniformly. And to improve the yield.

  In order to achieve the above object, according to the present invention, the polishing apparatus is configured to provide a stepped portion on the surface of the polishing pad.

  Specifically, a first polishing apparatus according to the present invention includes a carrier that holds a wafer and a retainer ring, and a platen to which a polishing pad is attached, and the polishing pad is on the surface of the wafer. In the region where the outer peripheral portion of the wafer contacts when pressed by the step, there is a stepped portion consisting of a flat portion and a convex portion, and the stepped portion is flattened by the pressing by the wafer.

  According to the first polishing apparatus of the present invention, the polishing pad is composed of a flat portion and a convex portion on the surface thereof and in a region where the outer peripheral portion of the wafer contacts when pressed by the wafer. A step portion is provided, and the step portion is flattened by pressing with the wafer. For this reason, since the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer, the number of chips that can be taken is increased, It is possible to improve the yield by preventing the film from peeling off at the outer peripheral portion.

A second polishing apparatus according to the present invention includes a carrier that holds a wafer and a retainer ring,
And a platen to which a polishing pad is attached, the polishing pad being on the surface thereof, except for the retainer ring that is pressed by the wafer and swings in a direction perpendicular to the rotation axis. In this case, a step portion including a flat portion and a convex portion is provided in a region where only the outer peripheral portion of the wafer contacts, and the step portion is flattened by pressing with the wafer.

  According to the second polishing apparatus of the present invention, the polishing pad has a retainer ring on the surface thereof, which is pressed by the wafer and swings in a direction perpendicular to the rotation axis. Except for the area where only the outer peripheral part of the wafer contacts, there is a step part consisting of a flat part and a convex part, and the step part is flattened by pressing with the wafer. For this reason, since the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer, the number of chips that can be taken is increased, It is possible to improve the yield by preventing the film from peeling off at the outer peripheral portion.

  In the first polishing apparatus and the second polishing apparatus according to the present invention, the stepped portion may be adjusted by the thickness of the polishing pad.

  In the first polishing apparatus and the second polishing apparatus according to the present invention, the stepped portion may be adjusted according to the processed shape of the surface of the platen.

  In the first polishing apparatus and the second polishing apparatus according to the present invention, it is preferable that the outer peripheral portion of the wafer is a region up to 3 mm from the peripheral end surface of the wafer toward the center.

  In the first polishing apparatus and the second polishing apparatus according to the present invention, the height from the flat portion to the convex portion is preferably 1 mm or less.

  A first polishing method according to the present invention uses a polishing apparatus including a carrier that holds a wafer and a retainer ring, and a platen to which the polishing pad is attached, and presses the retainer ring and the wafer against the polishing pad. The polishing pad includes a step of polishing while rotating both the wafer and the polishing pad, and the polishing pad has a flat portion and a convex shape on the surface thereof and in a region where the outer peripheral portion of the wafer contacts when pressed by the wafer. The step portion is flattened by pressing with a wafer.

  According to the first polishing method of the present invention, the polishing pad comprises a flat portion and a convex portion on the surface thereof and in a region where the outer peripheral portion of the wafer contacts when pressed by the wafer. A step portion is provided, and the step portion is flattened by pressing with the wafer. For this reason, since the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer, the number of chips that can be taken is increased, It is possible to improve the yield by preventing the film from peeling off at the outer peripheral portion.

  A second polishing method according to the present invention uses a polishing apparatus including a carrier for holding a wafer and a retainer ring and a platen to which the polishing pad is attached, and presses the retainer ring and the wafer against the polishing pad. The polishing pad includes a step of performing polishing while rotating the wafer and the polishing pad together. The polishing pad is pressed on the surface of the wafer and is pressed by the wafer and the wafer is swung in a direction perpendicular to the rotation axis. It has a step part consisting of a flat part and a convex part in a region where only the outer peripheral part of the wafer contacts except for the retainer ring, and the step part is flattened by pressing with the wafer. Features.

  According to the second polishing method of the present invention, the polishing pad has a retainer ring on the surface thereof, which is pressed by the wafer and swings in a direction perpendicular to the rotation axis. Except for the area where only the outer peripheral part of the wafer contacts, there is a step part consisting of a flat part and a convex part, and the step part is flattened by pressing with the wafer. For this reason, since the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer, the number of chips that can be taken is increased, It is possible to improve the yield by preventing the film from peeling off at the outer peripheral portion.

  According to the polishing apparatus and the polishing method of the present invention, the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. It is possible to increase the number of chips that can be taken, prevent film peeling at the outer periphery of the wafer, and improve the yield.

1A is a schematic plan view of a polishing apparatus according to a first embodiment of the present invention. FIG. (B) and (c) shows the polishing apparatus according to the first embodiment of the present invention, (b) is a schematic sectional view before pressing the wafer against the polishing pad, and (c) shows the wafer. FIG. 3 is a schematic cross-sectional view after pressing against a polishing pad (during polishing). (A) is sectional drawing before pressing the wafer in the polishing apparatus which concerns on the 1st Embodiment of this invention to a polishing pad, (b) is the wafer in the polishing apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows distribution of the pressure concerning a cross-sectional view and a wafer after pressing against a polishing pad (during polishing). (A) is sectional drawing before pressing the wafer to a polishing pad in the polisher concerning the modification of the 1st embodiment of the present invention, and (b) is a modification of the 1st embodiment of the present invention. It is a figure which shows distribution of the pressure concerning a cross-sectional view after the wafer is pressed against the polishing pad in the polishing apparatus according to the example (during polishing) and the wafer. (A) is a typical top view of the polish device concerning a 2nd embodiment of the present invention. (B) and (c) shows a polishing apparatus according to a second embodiment of the present invention, (b) is a schematic sectional view before pressing the wafer against the polishing pad, and (c) shows the wafer. FIG. 3 is a schematic cross-sectional view after pressing against a polishing pad (during polishing). (A) is sectional drawing before pressing the wafer in the polishing apparatus which concerns on the 2nd Embodiment of this invention to a polishing pad, (b) is a wafer in the polishing apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows distribution of the pressure concerning a cross-sectional view and a wafer after pressing against a polishing pad (during polishing). (A) is a typical top view of the polish device concerning a 3rd embodiment of the present invention. (B)-(e) shows the polish device concerning a 3rd embodiment of the present invention, (b) is a typical sectional view before pressing a wafer against a polish pad, and (c)-(e ) Is a schematic cross-sectional view after the wafer is pressed against the polishing pad (during polishing). (A) is sectional drawing before pressing the wafer in the polishing apparatus which concerns on a 1st prior art example to a polishing pad, (b) pressed the wafer in the polishing apparatus which concerns on a 1st prior art example to the polishing pad. FIG. 6 is a cross-sectional view after the polishing (during polishing) and a distribution of pressure applied to the wafer. (A) is sectional drawing before pressing the wafer in the polishing apparatus which concerns on a 2nd prior art example on a polishing pad, (b) is the wafer in the polishing apparatus which concerns on a 2nd prior art example FIG. 6 is a cross-sectional view after the polishing (during polishing) and a distribution of pressure applied to the wafer. (A) is sectional drawing before pressing the wafer in the polishing apparatus which concerns on a 3rd prior art example to a polishing pad, (b) has pressed the wafer in the polishing apparatus which concerns on a 3rd prior art example to the polishing pad. FIG. 6 is a cross-sectional view after the polishing (during polishing) and a distribution of pressure applied to the wafer.

(First embodiment)
A polishing apparatus and a polishing method according to a first embodiment of the present invention will be described with reference to FIGS.

  First, the polishing apparatus according to the first embodiment of the present invention will be described.

  As shown in FIGS. 1A and 1B, a polishing pad 12 is stuck on a flat platen 11. A carrier (not shown) is provided on the polishing pad 12, and a retainer ring 14 for holding the side surface and the back surface of the wafer 13 is provided on the carrier. The retainer ring 14 is provided to prevent the wafer 13 from jumping out of the carrier during polishing. On the surface of the polishing pad 12, the outer contact region 15 and the inner contact region 16 that are in contact with only the outer peripheral portion of the wafer 13 are convex as compared to other regions.

  As shown in FIG. 1C, when the wafer 13 is pressed against the polishing pad 12, the pressed portion of the convex portion of the polishing pad 12 becomes flat.

  As shown in FIG. 2A, the polishing pad 12 is a laminated pad in which an upper polishing pad 17 that is a hard layer and a lower polishing pad 18 that is a soft layer are laminated. Thereby, flatness is improved and in-plane uniformity is ensured. The lower polishing pad 18 is flat, and the surface of the upper polishing pad 17 is a polishing pad thickness adjustment in which the outer peripheral portion of the wafer 13 (for example, an area of about 3 mm in the central direction from the peripheral end surface of the wafer 13) is in contact. A stepped portion 20 is formed by gently sloping the region 19. The width of the polishing pad thickness adjustment region 19 is, for example, 5 mm or less. The height H of the convex portion, which is the height from the flat portion of the upper layer polishing pad 17 to the top surface of the convex portion, is determined in consideration of an increase in the desired polishing rate. Here, it is preferably 1 mm or less. In the wafer 13, a pressure zone control region 21 capable of pressure zone control is provided in a region closer to the center than the polishing pad thickness adjustment region 19.

  For processing the thickness of the upper polishing pad 17, processing by cutting, processing by diamond dress, or the like is used.

  When polishing is performed with the stepped portion 20, as shown in FIG. 2B, the pressure applied to the wafer 13 in the polishing pad thickness adjusting region 19 can be made larger than that in other regions. The pressure applied to the wafer 13 is not affected. By the way, since the wafer 13 is rotating, when the outer peripheral portion of the wafer 13 passes through the polishing pad thickness adjustment region 19, the pressure becomes larger than the center of the wafer 13 (the polishing rate increases), and the polishing pad. When the thickness adjustment region 19 is passed, the pressure is reduced compared to the center of the wafer 13 or the like (the polishing rate is reduced). Since the average polishing rate is determined by this integration, considering this point, determination of the polishing rate when the outer peripheral portion of the wafer 13 passes through the polishing pad thickness adjustment region 19, that is, the height of the convex portion It is necessary to determine H.

  As shown in FIGS. 3A and 3B, the same effect can be obtained by adjusting the thickness of the lower polishing pad 18 instead of the upper polishing pad 17 in the polishing pad thickness adjustment region 19. it can. However, since the elastic modulus changes between the upper layer polishing pad 17 and the lower layer polishing pad 18, the adjustment amount of the thickness is not the same.

  Although both the outer contact region 15 and the inner contact region 16 are convex with respect to the surface of the polishing pad 12, either one may be used. In that case, it is more effective to make the outer contact region 15 convex.

  So far, the polishing apparatus for increasing the polishing rate of the outer peripheral portion of the wafer 13 has been described. However, if the thickness of the flat portion of the polishing pad 12 and the thickness of the convex portion are reversed, the polishing rate can be lowered. It is.

  According to the polishing apparatus of the first embodiment of the present invention, the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. it can. As a result, the number of chips that can be taken increases, leading to the effect of reducing the chip cost. From this point of view, the present invention is directed to all steps of the chemical mechanical polishing (CMP) method. In addition, the yield can be improved because the generation of particles on the outer peripheral portion of the wafer is prevented.

  Next, a polishing method according to the first embodiment of the present invention will be described.

  As shown in FIGS. 1B and 1C, the wafer 13 is polished by pressing against the polishing pad 12 having a convex portion using the above-described polishing apparatus.

  As shown in FIGS. 2A and 2B, on the surface of the polishing pad 12, the outer contact region 15 and the inner contact region 16 that are in contact with only the outer peripheral portion of the wafer 13 are compared with other regions of the polishing pad 12. And convex. When the wafer 13 is pressed against the polishing pad 12, the pressed portion of the convex portion of the polishing pad 12 becomes flat. As a result, the polishing rate of the outer peripheral portion of the wafer 13 is increased, and the polishing rates of other regions are not affected.

  According to the polishing method of the first embodiment of the present invention, the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. it can. As a result, the number of chips that can be taken increases, leading to the effect of reducing the chip cost. From this point of view, the present invention is intended for all steps of the CMP method. In addition, the yield can be improved because the generation of particles on the outer peripheral portion of the wafer is prevented.

(Second Embodiment)
Hereinafter, a polishing apparatus according to a second embodiment of the present invention will be described with reference to FIGS. In 2nd Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol about the same member as 1st Embodiment, and only a different part is demonstrated.

  Unlike the first embodiment, the polishing apparatus according to the second embodiment has a gentle slope due to the steps in the central part and the peripheral part of the platen.

  Specifically, as shown in FIGS. 4A to 4C and FIG. 5A, on the surface of the polishing pad 12, the outer peripheral portion of the wafer (for example, about 3 mm from the peripheral end surface of the wafer 13 toward the center). The stepped portion 20 is formed by providing a gentle slope to the upper surface of the platen 11 in the platen flatness adjusting region 22 that is a region in contact with the region. The width of the platen flatness adjustment region 22 is, for example, 5 mm or less. The height H of the convex portion, which is the height from the flat portion of the polishing pad 12 to the top surface of the convex portion, is determined in consideration of an increase in the desired polishing rate. Here, it is preferably 1 mm or less.

  When polishing is performed by providing the stepped portion 20, the pressure applied to the wafer 13 in the platen flatness adjusting region 22 can be made larger than the other regions as shown in FIG. The pressure on the wafer 13 in the region is not affected. By the way, since the wafer 13 is rotating, when the outer peripheral portion of the wafer 13 passes through the platen flatness adjustment region 22, the pressure becomes larger than the center of the wafer 13 (the polishing rate increases), and the platen flatness is increased. When the adjustment region 22 is passed, the pressure is reduced compared to the center of the wafer 13 or the like (the polishing rate is reduced). Since the average polishing rate is determined by this integration, considering this point, determination of the polishing rate when the outer peripheral portion of the wafer 13 passes through the platen flatness adjustment region 22, that is, the height H of the convex portion It is necessary to make a decision.

  In addition, although both the outer contact region 15 and the inner contact region 16 are convex with respect to the surface of the platen 11, either one may be used. In that case, it is more effective to make the outer contact region 15 convex.

  So far, the polishing apparatus for increasing the polishing rate of the outer peripheral portion of the wafer has been described. However, if the thickness of the flat portion of the platen 11 and the thickness of the convex portion are reversed, the polishing rate can be lowered. .

  According to the polishing apparatus of the second embodiment of the present invention, the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. it can. As a result, the number of chips that can be taken increases, leading to the effect of reducing the chip cost. From this point of view, the present invention is intended for all steps of the CMP method. In addition, the yield can be improved because the generation of particles on the outer peripheral portion of the wafer is prevented.

(Third embodiment)
Hereinafter, a polishing apparatus and a polishing method according to a third embodiment of the present invention will be described with reference to FIG. In 3rd Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol about the same member as 1st Embodiment and 2nd Embodiment, and only a different part is demonstrated.

  First, a polishing apparatus according to a third embodiment of the present invention will be described.

  As shown in FIGS. 6A and 6B, a polishing pad 12 having a convex portion is stuck on the platen 11. In this embodiment, the wafer 13 is pressed against the polishing pad 12 and swings in a direction perpendicular to the rotation axis. On the surface of the polishing pad 12, a step 20 is formed by gently inclining a region having a predetermined interval from the peripheral end surface of the wafer 13 when the wafer 13 is located at the center of the region where the wafer 13 swings. Thus, a convex portion is formed. Here, the height H of the convex portion, which is the height from the flat portion of the polishing pad 12 to the top surface of the convex portion, is determined in consideration of an increase in the desired polishing rate. Here, it is preferably 1 mm or less.

  As shown in FIGS. 6C to 6E, when the wafer 13 is pressed against the polishing pad 12 and the wafer 13 is swung, the outer peripheral portion of the wafer 13 (for example, approximately from the peripheral end surface of the wafer 13 to the center direction). In the region where the 3 mm region) rides on the convex portion of the polishing pad 12, the convex portion of the polishing pad 12 is flattened. Here, the region where the stepped portion 20 is formed needs to be a region where only the outer peripheral portion of the wafer 13 except the retainer ring 14 contacts when the wafer 13 is swung. By doing so, the polishing rate of the outer peripheral portion of the wafer 13 is increased, and the polishing rates of other regions are not affected.

  According to the polishing apparatus of the third embodiment of the present invention, the polishing rate of the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. it can. By controlling the swing speed and range, the controllability of the polishing rate of the wafer outer peripheral portion is further improved as compared with the first embodiment. As a result, the number of chips that can be taken increases, leading to the effect of reducing the chip cost. From this point of view, the present invention is intended for all steps of the CMP method. In addition, the yield can be improved because the generation of particles on the outer peripheral portion of the wafer is prevented.

  In the present embodiment, the case where the polishing pad 12 is inclined as in the first embodiment has been described. However, the same effect can be obtained even when the platen is inclined as in the second embodiment. it can.

  Next, a polishing method according to the third embodiment of the present invention will be described.

  As shown in FIGS. 6B and 6C, the wafer 13 is pressed against the polishing pad 12 having a convex portion using the above polishing apparatus.

  As shown in FIGS. 6D and 6E, after the wafer 13 is pressed against the polishing pad 12, the wafer 13 is polished while being swung in a direction perpendicular to the rotation axis. On the surface of the polishing pad 12, a step 20 is formed by gently inclining a region having a predetermined distance from the peripheral end surface of the wafer 13 when the wafer 13 exists at the center of the region where the wafer 13 swings. Thus, a convex portion is formed. In the region where the wafer 13 rides on the convex portion of the polishing pad 12, the convex portion of the polishing pad 12 is crushed and becomes flat. The region where the stepped portion 20 is formed needs to be a region where only the outer peripheral portion of the wafer 13 excluding the retainer ring 14 contacts when the wafer 13 is swung. By doing so, the polishing rate of the outer peripheral portion of the wafer 13 is increased, and the polishing rates of other regions are not affected.

  According to the polishing method of the third embodiment of the present invention, the polishing rate at the outer peripheral portion of the wafer can be increased without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. it can. By controlling the swing speed and range, the controllability of the polishing rate at the outer peripheral portion of the wafer is further improved compared to the first embodiment. As a result, the number of chips that can be taken increases, leading to the effect of reducing the chip cost. From this point of view, the present invention is intended for all steps of the CMP method. In addition, the yield can be improved because the generation of particles on the outer peripheral portion of the wafer is prevented.

  The polishing apparatus and the polishing method according to the present invention can increase the polishing rate of the outer peripheral portion of the wafer without sacrificing the in-plane uniformity of the polishing rate in the inner region excluding the outer peripheral portion of the wafer. A wafer polishing apparatus using a chemical mechanical polishing (CMP) method, particularly in the manufacturing process of a semiconductor integrated circuit, etc., in order to improve the yield by preventing film peeling at the outer peripheral portion of the wafer. And useful for polishing methods and the like.

DESCRIPTION OF SYMBOLS 11 Platen 12 Polishing pad 13 Wafer 14 Retainer ring 15 Outer contact area 16 Inner contact area 17 Upper layer polishing pad 18 Lower layer polishing pad 19 Polishing pad thickness adjustment area 20 Step part 21 Pressure zone control area 22 Platen flatness adjustment area

Claims (8)

A carrier for holding the wafer and the retainer ring;
With a platen with a polishing pad attached,
The polishing pad has a stepped portion formed of a flat portion and a convex portion on the surface thereof, in a region where the outer peripheral portion of the wafer contacts when pressed by the wafer,
The polishing apparatus according to claim 1, wherein the stepped portion is flattened by pressing with the wafer. A carrier for holding the wafer and the retainer ring;
And a platen with a polishing pad attached,
The polishing pad is only on the outer surface of the wafer except for the retainer ring on the surface thereof, when the wafer is pressed by the wafer and the wafer swings in a direction perpendicular to the rotation axis. Has a step portion composed of a flat portion and a convex portion in a region where the
The polishing apparatus according to claim 1, wherein the stepped portion is flattened by pressing with the wafer.   The polishing apparatus according to claim 1, wherein the step portion is adjusted by a thickness of the polishing pad.   The polishing apparatus according to claim 1, wherein the stepped portion is adjusted by a processed shape of a surface of the platen.   The polishing apparatus according to claim 1, wherein the outer peripheral portion of the wafer is a region extending from the peripheral end surface of the wafer to a center direction of 3 mm.   The polishing apparatus according to claim 1, wherein a height from the flat portion to the convex portion is 1 mm or less. Using a polishing apparatus comprising a carrier for holding the wafer and the retainer ring and a platen to which a polishing pad is attached, the retainer ring and the wafer are pressed against the polishing pad, and the wafer and the polishing pad are rotated together. A process of polishing while
The polishing pad has a stepped portion formed of a flat portion and a convex portion on the surface thereof, in a region where the outer peripheral portion of the wafer contacts when pressed by the wafer,
The polishing method, wherein the stepped portion is flattened by pressing with the wafer. Using the polishing apparatus comprising a carrier for holding the wafer and the retainer ring, and a platen to which the polishing pad is attached, the retainer ring and the wafer are pressed against and swung to the polishing pad, and the wafer and the polishing pad A process of polishing while rotating together,
The polishing pad is only on the outer surface of the wafer except for the retainer ring on the surface thereof, when the wafer is pressed by the wafer and the wafer swings in a direction perpendicular to the rotation axis. Has a step portion composed of a flat portion and a convex portion in a region where the
The polishing method, wherein the stepped portion is flattened by pressing with the wafer.

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