JP3955066B2 - Polishing pad, method for manufacturing the polishing pad, and method for manufacturing a semiconductor substrate using the polishing pad - Google Patents

Description

  The present invention relates to a polishing pad used for processing a surface of a semiconductor substrate such as a semiconductor wafer or a semiconductor device in a semiconductor manufacturing process, and a polishing pad related technique such as a method of manufacturing a semiconductor substrate using the polishing pad. It is about.

  Conventionally, as a processing method for flattening the surface of each layer when forming various thin films such as metal films and insulating films on a silicon wafer surface in a multilayer process in a semiconductor manufacturing process such as an LSI device, a synthetic resin has been used. Using a thin disc-shaped polishing pad made of a material or foamed material, a polishing pad and a wafer (semiconductor substrate) are relatively rotated while supplying a slurry made of fine particles and liquid between the wafer and the pad. A chemical mechanical polishing method called CMP (Chemical Mechanical Polishing) is known.

  By the way, in such a CMP method, in order to realize high integration and high accuracy of semiconductor devices by forming a multilayer of complicated fine structures, (a) the entire surface of the wafer has a high accuracy flattening ability. “Polishing accuracy” for polishing and (b) “polishing efficiency” for polishing a wafer with excellent work efficiency are required. In addition, the demands for both of these are becoming stronger, especially when the density of semiconductor devices in recent years is further increased.

  Therefore, in order to cope with such a demand, conventionally, with respect to the polishing pad used in the CMP method, a large number of small holes are provided on the surface of the polishing pad (the surface on which the wafer is polished) or linearly extend. The thing which provided the ditch | groove and the ditch | groove extended in the circumferential direction is proposed. For example, those described in Patent Documents 1, 2, 3 and the like.

  However, even if these conventional polishing pads are employed, it has been extremely difficult to achieve both “polishing accuracy” and “polishing efficiency” sufficient to meet the requirements. In particular, in the field of VLSI, the metal line width of the wiring formed on the wafer is extremely narrow, 0.18 μm or less, polished with a high surface roughness (Rz) of 0.25 μm or less, and soft copper In order to obtain satisfactory polishing accuracy and polishing efficiency in consideration of the current situation where the adoption of metal wiring made of metal, gold, etc. is already in the examination stage considering practical application, the polishing pad Further improvements are eagerly desired.

As one measure for improving the polishing accuracy in the CMP method, Patent Document 4 proposes a polishing pad in which concave grooves extending with a cross-sectional shape expanding toward the surface of the polishing pad are formed. According to the description of Patent Document 4, slurry and polishing debris are guided by the inclined side wall surface of the concave groove to improve the polishing accuracy.
However, as a result of investigation by the present inventor, when the groove as described in Patent Document 4 is formed on the surface of the polishing pad, the polishing performance including the polishing efficiency and the polishing accuracy is not stable, and the practical application is extremely difficult. It became clear that there was. The biggest reason for this is thought to be that the width dimension of the groove changes in the depth direction.

  That is, the polishing pad wears as the wafer is polished, and it is common to perform leveling (dressing) by cutting the surface of the pad every predetermined processing time. In the concave groove described in Document 4, it is inevitable that the groove width largely changes due to abrasion or surface leveling processing accompanying polishing, and various conditions such as stress distribution on the polished surface change significantly accordingly. Therefore, it is considered that stable polishing characteristics are not exhibited.

US Pat. No. 5,911,855 US Pat. No. 5,984,769 US Pat. No. 6,364,749 US Pat. No. 6,238,271

  Here, the present invention has been made to solve the above-described problems, and the problem to be solved is that, for example, the surface of a semiconductor substrate or the like is highly polished and stable by CMP or the like. An object of the present invention is to provide a polishing pad having a novel structure that can be processed with "accuracy" and "polishing efficiency".

  Further, the present invention manufactures a target semiconductor substrate with high and stable “accuracy” and “efficiency” by processing the surface of the semiconductor substrate by an appropriate polishing method such as CMP in the semiconductor manufacturing process. Another object of the present invention is to provide a novel method for manufacturing a semiconductor substrate using a polishing pad.

  Furthermore, another object of the present invention is to provide an advantageous manufacturing method of a polishing pad that can advantageously manufacture a polishing pad having a novel structure according to the present invention as described above.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. In addition, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized on the basis of.

(Aspect 1 regarding polishing pad)
Aspect 1 relating to the polishing pad is a polishing pad used for polishing a semiconductor substrate in which at least one groove is formed on the surface of a synthetic resin pad substrate, wherein at least a part of the groove is formed on the pad substrate. An inclined groove having substantially parallel both side wall surfaces inclined in the depth direction with respect to the central axis is characterized.

  In such an aspect, by adopting the inclined groove having the inclined side wall surface, the centrifugal force associated with the rotation of the polishing pad is applied to the slurry or the like existing in the concave groove, and the inclination angle of the inclined groove. As a result, it is possible to control the flow state of a slurry or the like existing between a semiconductor substrate such as a wafer and a polishing pad. In particular, in a polishing method using a specific slurry such as a CMP method, not only a mechanical polishing action but also a chemical polishing action has a great influence. Grain movement has a great influence on the accuracy and stability of polishing. Therefore, if this embodiment is applied to the wafer, the inclination direction and the inclination angle of the inclined grooves are appropriately adjusted to allow the wafer during polishing. By controlling the movement of the abrasive grains between the pad and the pad, for example, the polishing performance can be appropriately adjusted and set according to the material of the polishing pad, the required accuracy, and the like. Alternatively, for example, by appropriately adjusting the inclination direction and the inclination angle of the inclined groove, it is possible to suppress adverse effects due to foreign matters such as polishing waste generated during polishing. Etc. can be actively retained in the inclined groove by the action of centrifugal force, and on the contrary, it can be actively discharged from the inclined groove, thereby further improving the stability of the polishing accuracy. It becomes possible.

  In addition, in this embodiment, the width dimension of the concave groove including the inclined groove can be made substantially constant in the depth direction. Therefore, the abrasion of the polishing pad accompanying the progress of polishing and the surface of the polishing pad Even when the depth of the groove is changed by dressing or the like, the groove width of the groove is kept substantially constant, and the polishing performance including the target polishing efficiency and polishing accuracy can be maintained.

  In this aspect, the material of the pad substrate is not particularly limited, and various materials can be appropriately employed depending on the object to be polished, conditions required for polishing, and the like, for example, foamed or unfoamed A hard resin such as a polyurethane resin is preferably employed. In addition, the polishing pad having the structure according to the present embodiment is used for polishing by being fixed on a rotationally driven support plate according to a conventional method, but the fixing method to the support plate is limited. Needless to say, it may be fixed directly on the support surface of a rigid support plate such as metal, or may be fixed on the support surface of the support plate via an appropriate elastic pad.

(Mode 2 for polishing pad)
Aspect 2 relating to the polishing pad is characterized in that, in the polishing pad according to aspect 1, a circumferential groove extending in a substantially circumferential direction around the central axis of the pad substrate is formed as the inclined groove. In this aspect, since the inclined groove is constituted by the circumferential groove, the action of the centrifugal force based on the rotation of the polishing pad around the rotation center axis is more effective against the slurry in the inclined groove, the polishing debris, etc. It can be exerted more effectively.

(Aspect 3 regarding polishing pad)
Aspect 3 relating to the polishing pad is characterized in that, in the polishing pad according to aspect 2, the both side wall surfaces of the circumferential groove are inclined outward in the radial direction of the pad substrate in the depth direction toward the opening. And In this aspect, by supplying a flow in the direction of exiting the inclined groove to the slurry or the like existing in the inclined groove or polishing debris, for example, supply between the polishing pad and the wafer from the central portion of the polishing pad. It is possible to more effectively prevent clogging of the inclined grooves due to the circulation of the slurry and the like, and the entry of polishing debris and the like.

(Aspect 4 regarding polishing pad)
Aspect 4 related to the polishing pad is the polishing pad according to the aspect 2 or 3, wherein the circumferential grooves are separated from each other on the radial line of the pad substrate and formed in multiple layers, and slopes of both side walls of the circumferential grooves are formed. The angle is varied in accordance with the radial distance from the central axis of the pad substrate. In this aspect, it becomes possible to control the flow state of slurry and the like in a variety of directions in the radial direction of the polishing pad. For example, considering that the centrifugal force acting on the slurry in the inclined groove differs depending on the radial distance from the central axis of the polishing pad, the inclination angle of the sidewall surface of the inclined groove is changed in the radial direction. Thus, by gradually or stepwise changing, it becomes possible to make the action of the centrifugal force exerted on the slurry in the concave groove in the entire polishing pad as constant as possible over a wide range of the polishing pad.

(Aspect 5 regarding polishing pad)
Aspect 5 related to the polishing pad is characterized in that, in the polishing pad according to any one of the aspects 1 to 4, a plurality of linear grooves extending linearly are formed as the inclined grooves. Also in this aspect, the polishing pad can be actively flowed and retained with respect to the slurry and polishing waste in the inclined groove by the action of the centrifugal force based on being rotated around the rotation center axis, In addition, the flow of the slurry and the like can be controlled by adjusting the position, number, and the like in addition to the inclination angle of the inclined groove. In addition, this aspect may be combined with any one of the above-described aspects 2 to 4 to combine the circumferential groove and the linear groove to form both on the surface of one polishing pad.

(Aspect 6 regarding polishing pad)
Aspect 6 relating to the polishing pad is the polishing pad according to aspect 5, wherein a plurality of groove groups extending in parallel with each other are formed as the linear grooves, and the groove groups are formed in a substantially mesh shape. It is characterized by crossing. In this embodiment, by adopting a plurality of groove groups, it becomes possible to make the action of the linear grooves as uniform as possible over the entire polishing surface of the polishing pad, and further stabilize the polishing accuracy and polishing efficiency. Can be.

(Aspect 7 regarding polishing pad)
Aspect 7 relating to the polishing pad is the polishing pad according to aspect 6, wherein the multiple linear grooves constituting each groove group extend in parallel with the multiple linear grooves including the central axis of the pad substrate. It is characterized in that it is formed at a position and an inclination direction that are substantially symmetrical with respect to one surface. In this aspect, the action of the linear groove on the polishing surface of the polishing pad can be made more uniform. It is desirable that the linear groove formed at a position extending in the radial direction so as to intersect the central axis of the pad substrate is a concave groove having both side wall surfaces rising in parallel with the central axis of the pad substrate without being inclined.

(Aspect 8 regarding polishing pad)
Aspect 8 relating to the polishing pad is characterized in that, in the polishing pad according to any one of the aspects 1 to 7, the width dimension of the inclined groove is 0.005 to 2.0 mm. In this aspect, by making the width dimension of the inclined groove sufficiently narrow, a higher degree of polishing accuracy can be realized. In this case, the width of the inclined groove is increased by inclining the side wall surface of the inclined groove. Problems such as retention of slurry in the groove and clogging of polishing debris in the groove, which are likely to occur due to narrowing the dimensions, can be avoided very effectively, The desired polishing accuracy can be effectively and stably exhibited.

  The depth dimension and radial pitch of the groove are not particularly limited, and depends on the material of the polishing pad, the material to be polished, the properties of the slurry used, the required polishing accuracy and conditions, etc. In general, the depth dimension of the concave groove is 0.1 to 2.0 mm, particularly in the case of a substantially circular groove extending in the circumferential direction, an interval of 0.1 to 3.0 mm. It is desirable to form the inclined grooves substantially in parallel. However, in the case of linear grooves, even if the distance between the grooves is large, the local action on the object to be polished is reduced based on the rotation of the polishing pad, compared to the circular groove extending in the circumferential direction. Even if the interval between the grooves is set large, it is easy to obtain good polishing characteristics. For example, it is preferable to appropriately determine the interval between the grooves in a wide range of 0.1 to 60.0 mm.

(Aspect 9 regarding polishing pad)
Aspect 9 relating to the polishing pad is characterized in that, in the polishing pad according to any one of the aspects 1 to 8, the groove size error in the inclined groove is 5% or less. In this aspect, by improving the dimensional accuracy of the inclined groove to a predetermined value, it is possible to advantageously suppress variations in polishing pressure exerted on the semiconductor substrate when polishing the semiconductor substrate. Therefore, it is possible to suppress variations in the polishing pressure to a range of 2% or less of the target polishing pressure. Here, the groove dimension error in the inclined groove includes not only the groove width but also the groove pitch and groove depth dimensions.

(Aspect 1 related to semiconductor substrate manufacturing method)
Aspect 1 relating to a method of manufacturing a semiconductor substrate is characterized in that the semiconductor substrate is polished using a polishing pad having an inclined groove having a structure according to each aspect as described above. According to the method of this aspect, the movement of abrasive grains such as slurry between the semiconductor substrate and the polishing pad is caused by the action of the inclined grooves formed on the surface of the polishing pad as described above. It is possible to control based on the rotation speed and the like, thereby making it possible to manufacture the target semiconductor substrate with excellent polishing accuracy and polishing efficiency. In particular, according to the method of this aspect, it is possible to advantageously perform polishing of a semiconductor substrate having a wiring structure having a metal line width of 0.18 μm or less.

(Aspect 2 relating to semiconductor substrate manufacturing method)
Aspect 2 relating to a method of manufacturing a semiconductor substrate is a method of manufacturing a semiconductor substrate according to aspect 1, characterized in that the semiconductor substrate is polished while suppressing variations in polishing pressure to 2% or less. By limiting the variation in polishing pressure to 2% or less, it is possible to process the semiconductors currently planned with excellent yield. In particular, it has been confirmed by the present inventor that it is advantageously realized by using a pad having a structure according to the above-mentioned aspect 9 concerning a polishing pad.

(Aspect 1 relating to a method for producing a polishing pad)
Aspect 1 relating to the method of manufacturing a polishing pad is a method of using a cutting tool provided with a blade portion in which the side surface of the blade is inclined and brought into contact with the surface of the pad substrate made of synthetic resin, with respect to the central axis of the pad substrate. It is characterized in that an inclined groove having substantially parallel both side walls inclined in the depth direction is cut and formed. By manufacturing the polishing pad according to this aspect, for example, inclined grooves can be easily formed on the surface of the polishing pad as compared with grooving using a rotary tool. The structure according to each aspect as described above Thus, it is possible to efficiently manufacture a polishing pad having inclined grooves.

(Aspect 2 related to polishing pad manufacturing method)
Aspect 2 relating to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to aspect 1, wherein the cutting tool is rotated with respect to the surface of the pad substrate while rotating the pad substrate made of synthetic resin around a central axis. The inclined groove extending in the substantially circumferential direction is formed by using a lathe. According to the manufacturing method of this aspect, a plurality of inclined grooves such as a circular shape concentrically extending in the circumferential direction of the polishing pad, a petal shape as shown in FIG. 13 of US Pat. No. 5,984,769, or a spiral shape is extended. An inclined groove or the like can be easily formed.

(Aspect 3 relating to a method for producing a polishing pad)
Aspect 3 related to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to aspect 1 or 2, wherein the blade portion of the cutting tool is gradually sent out in a direction inclined with respect to the surface of the pad substrate. It is characterized in that the target inclined groove is cut and formed by repeatedly cutting the inclined groove forming portion on the surface of the pad substrate a plurality of times. According to the manufacturing method of this aspect, the inclined groove having a smooth inner surface can be stably formed, and the target inclined groove can be formed with a sufficiently small groove width. In addition, when the inclined groove to be formed has a end, such as a straight groove or a spiral groove, it is desirable to gradually increase the protruding amount of the blade portion step by step when performing multiple times of cutting in one direction or reciprocating. . Specifically, for example, the protrusion amount of the blade portion is increased by a certain amount for each reciprocation, or the protrusion amount of the blade portion is increased by irregularly changing the protrusion amount by an appropriate amount. You can do it. On the other hand, when the inclined groove to be formed is endless like a circumferential groove, when performing a plurality of times of cutting repeatedly on the same circumference, the protruding amount of the blade part is a fixed amount for each round. In addition to increasing stepwise or irregularly by an appropriate amount, the protruding amount of the blade portion may be continuously increased regardless of the circumference.

(Aspect 4 relating to a method for producing a polishing pad)
Aspect 4 related to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to any one of aspects 1 to 3, wherein the inclined groove is cut and formed on the surface of the pad substrate using the cutting tool. An ion blow is blown from the rear of the blade part of the cutting tool to prevent chips from being charged, and the chips sent to the front of the blade part are sucked and collected in front of the blade part. Is a feature. According to the manufacturing method of this aspect, ions that neutralize static electricity charged in the pad base material and its slab (chip) by friction due to cutting are ejected together with compressed air from the vicinity of the blade portion of the cutting tool. It is possible to prevent chips from adhering to the grooves that have been cut. Furthermore, as described above, the chips that have been neutralized by static electricity and scattered on the surface of the pad base material can be quickly removed from the pad surface by suction. Therefore, in the case of grooving with a cutting tool, cutting problems such as large erosion of the wall surface of the inclined groove due to chips adhering to the wall surface of the inclined groove are eliminated, and the pad base has high dimensional accuracy. An inclined groove or the like can be formed in the material. Here, the spraying of ions and the suction and recovery of chips can be advantageously realized by using a known static electricity removing air blow device utilizing corona discharge, a dust collector, or the like. In addition, it is desirable that the ions are sprayed at an inclination angle substantially the same as the inclination angle of the inclined groove. It is possible to spray ions well on the inner peripheral surface and bottom surface of the inclined groove that is covered and undercut with respect to the surface of the pad substrate. This is because the powder can also be advantageously sucked and collected.

(Aspect 5 relating to a method for producing a polishing pad)
Aspect 5 relating to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to any one of aspects 1 to 4, wherein a plurality of the blade portions are provided in parallel to the cutting direction as the cutting tool. When simultaneously forming the multiple inclined grooves using a multi-blade tool, the ion blow sprayed from the rear of the multi-blade tool is sent out to the front of the multi-blade tool through the gaps of the plurality of blade portions. It is characterized by. According to the manufacturing method of this aspect, the chip is advantageously prevented from adhering to the groove wall surface even when a multi-blade tool is used, by using the gap between the multi-blades to let the chips escape to the front of the cutting tool. can do.

(Aspect 1 related to cutting tool)
Aspect 1 relating to the cutting tool is a cutting tool provided with a blade portion for cutting and forming a concave groove on the surface of a pad substrate made of synthetic resin, and the cutting portion of the blade portion is provided with respect to the blade edge provided on the blade portion. It is characterized in that side surfaces on both sides are inclined in the same lateral direction. By using the cutting tool structured according to this aspect, the method of manufacturing a polishing pad according to each aspect as described above can be advantageously implemented, and particularly, both side wall surfaces are inclined with respect to the central axis of the pad substrate, In addition, an inclined groove having a cross-sectional shape whose bottom surface is orthogonal to the central axis of the pad substrate can be formed by cutting.

(Aspect 2 regarding cutting tools)
Aspect 2 relating to the cutting tool is the cutting tool according to aspect 1, wherein a plurality of the blade portions are provided in parallel to the cutting direction to form a multi-blade tool, thereby simultaneously cutting and forming the multiple grooves. It is characterized by being able to do it. In this embodiment, it is possible to efficiently cut and form the inclined grooves as a large number of concave grooves, and the productivity can be improved.

(Aspect 3 regarding cutting tools)
Aspect 3 relating to the cutting tool has a structure according to each aspect as described above by turning a concave groove extending in a substantially circumferential direction with respect to the surface of the pad substrate while rotating the pad substrate about the central axis. A grooving tool for manufacturing a polishing pad, wherein the blade width is 0.005 to 3.0 mm, the blade angle is 15 to 35 degrees, and the front clearance angle is 65 to 45 degrees. The cutting tool for groove processing provided is a feature.

  By using the cutting tool having the structure according to this embodiment, it becomes possible to more advantageously form a groove (including an inclined groove) by cutting the polishing pad, and the inner surface of the groove to be formed. It is possible to improve the roughness and shape stability. In particular, by setting the front clearance angle to 65 to 45 degrees, when the concave groove is cut to a sufficiently inner peripheral side of the pad substrate with a small radius of curvature, the hooking of the side surface of the blade portion is reduced or avoided. As a result, the side wall surface on the outer peripheral side of the target groove can be formed with high accuracy and a stable dimension, and the substantially uniform substantially circumferential shape can be obtained over a wide area of the polishing pad. It is possible to form the groove extending in the direction with higher accuracy.

  Moreover, in such a cutting tool for grooving, the blade width is more preferably 0.005 to 2.0 mm. Such a narrow tool is employed. Further, in the grooving tool according to this aspect, a structure in which a plurality of blade portions are arranged in the blade width direction is advantageously employed, thereby efficiently forming a plurality of concentric concave grooves. It is possible to form a turning. When configuring a multi-blade tool in which a plurality of blade portions are arranged in the blade width direction, the blade portions may be provided at the same pitch as the target concave groove formation pitch (interval). The groove pitch intended for such a multi-blade tool while ensuring a certain gap between adjacent blades as a suitable multiple of at least twice the formation pitch of the groove for the purpose. Accordingly, a plurality of grooves may be cut and formed at a time by slightly shifting according to the above.

  The effect of the present invention is as shown in the description in the above-mentioned “Means for Solving the Problems” and the following in the “Best Mode for Carrying Out the Invention”.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows a polishing pad 10 as an embodiment of the present invention. The polishing pad 10 is formed of a thin disk-shaped pad substrate 12 having a constant thickness dimension T as a whole. The pad substrate 12 is advantageously formed of, for example, hard foamed urethane. The thickness dimension of the pad is not limited, and is appropriately set according to not only the material of the pad substrate 12 but also the material of the wafer to be processed, the required processing accuracy, and the like.

  Further, a concave groove 16 extending in the circumferential direction is formed around the central axis 18 of the pad substrate 12 on the surface 14 as a processing surface, which is one surface of the pad substrate 12, and is open to the surface 14. It has been.

  As shown in FIG. 1, the concave groove 16 includes a plurality of circular grooves 16, 16, 16... Each extending around a central axis 18 and having different curvature radii. Alternatively, as shown in FIG. 2, it may be constituted by one or a plurality of spiral grooves 16 having a radius of curvature that gradually increases around the central axis 18. . In addition, a large number of concentric circular grooves as shown in FIG. 1 or single or plural spiral grooves as shown in FIG. In this case, the radial pitch, which is the separation distance of the intersection point of the groove with respect to the radial line, may be constant over the entire radial direction, or may be gradually changed partially or over the whole. .

  Here, the concave groove 16 is an inclined groove having a specific inclined structure according to the present invention in at least a part of the pad substrate 12 in the radial direction.

  Specifically, for example, as shown in FIG. 3, which is an enlarged explanatory view of a longitudinal section, the concave groove 16 has an inner peripheral side wall surface (hereinafter referred to as “inner wall surface”) 20 and an outer peripheral side. Each of the side wall surfaces (hereinafter referred to as “outer wall surfaces”) 22 is inclined by a predetermined angle: α (intersection angle = α with respect to a straight line parallel to the central axis 18) with respect to the central axis 18 over the entire length in the circumferential direction. It is assumed that the inclined surface. In short, in the groove 16 shown in FIG. 3, the inner wall surface 20 and the outer wall surface 22 are parallel to each other, and not only in the circumferential direction but also in the depth direction of the groove 16. The overall width of the groove 16 is substantially constant B, and the concave groove 16 is gradually separated from the central axis 18 toward the outer periphery as it goes to the opening, and toward the outer side in the radial direction of the pad substrate 12. Open.

  The bottom surface of the concave groove 16 is not limited in shape or the like, and may be any one of a curved surface and a flat surface. In particular, in this embodiment, the bottom surface of the concave groove 16 is the surface of the polishing pad 12. The flat surface is orthogonal to the central axis 18. Thus, even when the effective depth of the groove 16 is set large by making the bottom surface of the groove 16 a flat surface substantially parallel to the surface of the polishing pad 12, the gap of the bottom wall portion of the groove 16 is advantageous. It is possible to ensure good strength characteristics.

  In addition to the material, thickness, and outer diameter of the pad substrate 12, the specific set values such as the size of each part and the inclination angle of the groove 16 are the material of the wafer to be polished and the metal formed on the wafer. The shape is determined in consideration of the shape and material of the wire and the required polishing accuracy, and is not particularly limited. Generally, the groove 16 has a groove width: B and a depth: D. , Radial pitch: P and inclination angle: α are preferably set within the following ranges.

[In the case of a substantially circular circumferential groove]
0.005mm ≤ B ≤ 3.0mm
0.1mm ≤ D ≤ 2.0mm
0.1mm ≤ P ≤ 10.0mm
0.5 degrees ≤ α ≤ 30 degrees (in the case of a straight groove)
0.005mm ≤ B ≤ 3.0mm
0.1mm ≤ D ≤ 2.0mm
0.1mm ≤ P ≤ 60.0mm
0.5 degrees ≤ α ≤ 30 degrees

More preferably, it is set within the following range.
[In the case of a substantially circular circumferential groove]
0.05mm ≤ B ≤ 2.0mm
(Even more preferably, 0.2 mm ≦ B ≦ 1.0 mm)
0.1mm ≤ D ≤ 1.0mm
0.2mm ≤ P ≤ 5.0mm
1.0 degree ≦ α ≦ 20 degree (more preferably, 1.0 degree ≦ α ≦ 15 degree)
[In the case of straight groove]
0.05mm ≤ B ≤ 2.0mm
0.1mm ≤ D ≤ 1.0mm
0.2mm ≤ P ≤ 30.0mm
1.0 degree ≦ α ≦ 20 degree (more preferably, 1.0 degree ≦ α ≦ 15 degree)

  If the groove width B of the groove 16 is too small, the flow control effect of the slurry due to the formation of the groove 16 is difficult to be exerted, and clogging of the groove 16 due to polishing debris etc. It tends to occur and it is difficult to achieve a stable effect. On the other hand, if the groove width B of the concave groove 16 is too large, the contact surface pressure with the wafer at the edge portion (opening edge portion) of the concave groove 16 is increased, so that biting-like polishing is likely to occur and is stable. Polishing is difficult to achieve.

  In addition, if the groove depth D of the concave groove 16 is too small, it is difficult to exert the slurry flow control effect due to the formation of the inclined concave groove 16, and the rigidity of the surface 14 of the polishing pad 10 is low. The contact surface pressure with the wafer becomes uniform as a whole because it becomes too large, and the contact surface pressure with the wafer at the edge portion of the concave groove 16 does not sufficiently increase, and effective polishing tends to be difficult. On the other hand, if the groove depth D of the concave groove 16 is too large, not only manufacturing is difficult, but also the surface 14 of the polishing pad 10 is easily deformed, and stick slip may occur, resulting in unstable polishing. easy.

  Furthermore, when the radial pitch P of the concave grooves 16 is too small, manufacturing is difficult, and deformation and damage of the surface 14 of the polishing pad 10 are likely to occur, and stable polishing is difficult to be realized. On the other hand, if the radial pitch P of the concave grooves 16 is too large, the slurry flow control effect and the like due to the formation in the concave grooves 16 are hardly exhibited.

  Furthermore, if the inclination angle α of the inner and outer wall surfaces 20 and 22 is too small, the slurry flow control effect by centrifugal force described later tends to be hardly exhibited. On the other hand, if the inclination angle α of the inner and outer wall surfaces 20 and 22 is too large, not only the manufacturing becomes difficult, but also the strength of the side wall portion of the groove 16 is lowered and the surface pressure distribution becomes difficult to stabilize. The durability of 10 may be difficult to obtain sufficiently.

  The polishing pad 10 provided with such a concave groove 16 is used for polishing a wafer or the like in the same manner as in the prior art. Specifically, for example, as shown in FIG. 4, it is placed on a support surface of a rotating plate (supporting plate) of a polishing apparatus (not shown), and is applied to the rotating plate by means such as negative pressure suction by air. Fixed and mounted. Then, the wafer 24 is superposed on the surface 14 while being driven to rotate around the central axis 18, thereby being subjected to a polishing process. In such a polishing process, a polishing liquid (slurry) 28 is generally supplied to the space between the surface 14 of the polishing pad 10 and the surface to be processed 26 of the wafer 24 as in the prior art. The wafer 24 itself is also driven to rotate around its central axis. The polishing liquid 28 is supplied from the vicinity of the center of the polishing pad 10 to the surface of the polishing pad 10, for example, and spreads on the surface of the polishing pad 10 by the action of centrifugal force accompanying the rotation around the central axis 12 of the polishing pad 10. Is done.

  In such a polishing pad 10, the groove 16 opened on the pad surface 14 is formed so as to be gradually inclined radially outward from the bottom toward the opening. By being driven to rotate around the central axis 18, a centrifugal force exerted on the slurry 28 filled in the concave groove 16 generates a component force in the direction of flowing out of the concave groove 16, and the rotational speed of the polishing pad 10 is increased. With the force corresponding to the above, it flows out from the opening to the outer peripheral side and is made to flow so as to enter between the opposing surfaces of the polishing pad 10 and the wafer 24. At the same time, on the inner peripheral side of the concave groove 16, an amount of the slurry 28 corresponding to the amount flowing out from the concave groove 16 to the outer peripheral side is positively introduced into the concave groove 16.

  As a result, efficient inflow / outflow of the slurry is performed in the concave groove 16, and a positive slurry flow is developed between the opposing surfaces of the polishing pad 10 and the wafer 24. Not only the mechanical polishing action but also the chemical polishing action by the slurry can be generated very efficiently and substantially uniformly throughout, and effective polishing can be realized stably.

  Moreover, by adopting the groove 16 inclined as described above, the flow state of the slurry during polishing can be positively controlled simply by adjusting the inclination angle of the groove 16 appropriately. Therefore, for example, the optimum polishing state can be easily realized by adjusting the inclination angle of the concave groove 16 in consideration of the characteristics of the slurry to be adopted and the characteristics of the symmetrical wafer, as well as various polishing conditions. Is possible. Specifically, for example, in adjusting the polishing temperature, it is possible to adjust the holding of the polishing temperature by increasing the flow rate of the slurry by inclining the groove 16 toward the outside of the pad. is there.

  Further, in the inclined groove 16, the side wall surfaces 20 and 22 are parallel to each other not only in the circumferential direction but also in the depth direction, so that the groove width dimension B of the groove 16 is in the depth direction. Since the entire surface is substantially constant, even when the surface of the polishing pad 10 is worn or when surface grinding is performed by dressing, the width dimension of the concave groove 16 opened to the surface 14 is substantially constant. There is also an advantage that a stable polishing action can be exhibited over a long period of time.

  Incidentally, the following [Table 1] shows the result of the simulation in which the change of the polishing performance of the polishing pad 10 on the wafer 24 when the opening width B of the concave groove 16 is changed is examined. As shown in FIG. 5, the simulation is performed on a polishing pad 10 in which concave grooves 16 having a depth of 1.0 mm are formed to extend parallel to each other at intervals of 1.25 mm. Width dimension: B value is initially set value: B = 0.25 mm, -20% (B = 0.20 mm), -5% (B = 0.2375 mm), + 5% (B = 0.2625 mm) ), + 20% (B = 0.30 mm). In the simulation, the cross-sectional dimension of the polishing pad 10 is a rectangular shape with a width: 3.75 mm and a thickness: 2 mm, and the cross-sectional dimension of the wafer 25 is a rectangular shape with a width: 3.75 mm and a thickness: 3 mm. The static state in which the wafer 25 was pressed against the surface of the polishing pad 10 with a static pressing load of 5 gf / mm 2 was subjected to stress analysis by a finite element method. Further, each groove 16 in the polishing pad 10 has a non-inclined shape extending in the overlapping direction of the polishing pad 10 and the wafer 25. The physical property values adopted for the wafer 25 and the polishing pad 10 are shown in [Table 2].

  From the results shown in [Table 1], the peak pressure (pressing force) exerted on the wafer 25 during polishing may change in% order even if the width dimension B of the concave groove 16 slightly changes. Is recognized. Since the magnitude of the peak pressure exerted on the wafer 25 directly affects the polishing efficiency at the time of wafer polishing and also greatly affects the polishing accuracy, the width dimension of the concave groove 16: B Maintaining the value as constant as possible is extremely important for stable processing of the wafer 25. Here, in the polishing pad 10 of the present embodiment as described above, the groove 16 is inclined, but since the value of the width dimension B is substantially constant in the depth direction, the polishing pad 10 Even when the surface is worn or when surface grinding is performed by dressing, stable polishing performance can be exhibited. On the other hand, when a groove having a cross-sectional shape that expands in the depth direction toward the pad surface as described in, for example, Patent Document 4 (US Pat. No. 6,238,271) is employed, polishing is performed. When the surface of the pad 10 is worn or when the surface layer is ground by dressing, the width of the groove changes, and the polishing performance of the wafer also changes. Therefore, it is extremely difficult to stably perform the target polishing on the wafer. It is easy to understand.

  Further, since the concave groove 16 is inclined with respect to the central axis 18 of the polishing pad 10, the centrifugal force component generated according to the inclination angle α is caused between the opposing surfaces of the polishing pad 10 and the wafer 25. As described above, the fluidity of the slurry supplied to the nozzle is improved, which leads to the improvement of the polishing efficiency and the polishing accuracy. In addition to the improvement of the slurry fluidity, the groove 16 is inclined. As a result, it has been confirmed that the maximum pressure of the contact surface of the polishing pad 10 with respect to the wafer 25 is increased and a phenomenon such as an edge effect occurs, thereby further improving the polishing efficiency. . The results of verifying this phenomenon by simulation are described below.

  In this simulation, as shown in FIG. 6, a polishing pad 10 in which concave grooves 16 having a depth of 1.0 mm are formed so as to extend in parallel with each other at intervals of 1.0 mm is used. Under the condition that the lower end surface is fixed and a pressing load of 5.0 gf / mm 2 is applied to the upper surface of the wafer 25 placed on the surface 14, the wafer 25 is placed in the horizontal direction with respect to the polishing pad 10 (in FIG. 6). (Right direction) was performed by simulating a polishing process using a finite element method by minute movement at a relative speed of 583.3 mm / s. Then, the inclination angle of the concave groove 16 is: α = 0 degrees (opening parallel to the pad central axis), α = −5 degrees (opening inclined toward the pad central axis), α = −10 FIGS. 7 to 11 show simulation results for five cases of degrees, α = + 5 degrees (inclined and opened toward the outer periphery of the pad), and α = + 10 degrees, respectively.

  In the simulation, the cross-sectional dimension of the polishing pad 10 is a rectangle having a width of 4.5 mm and a thickness of 2.5 mm, and the cross-sectional dimension of the wafer 25 is a width of 4.5 mm and a thickness of 3.0 mm. The rectangular shape. In addition, each groove 16 in the polishing pad 10 was fixed at a groove width dimension: B = 0.5 mm. The physical property values employed for the wafer 25 and the polishing pad 10 were in accordance with the values of the static simulation conditions (Table 2) regarding the groove width change described above.

  From these results shown in FIGS. 7 to 11, by changing the inclination angle of the concave groove 16, the contact surface pressure of the polishing pad 10 exerted on the wafer 25 during polishing can be significantly and effectively adjusted. It is clear. Then, as the inventors have conducted experiments and studied, as the maximum value of the contact surface pressure increases, specifically, the value of the inclination angle α of the groove 16 increases to the plus side within a predetermined range. It has been confirmed that the polishing efficiency can be improved as the pad is inclined toward the outer periphery of the pad. This is considered to be due to the polishing pad exhibiting an edge effect such as a bite. Accordingly, it is possible to obtain optimum polishing accuracy and polishing efficiency by adjusting the inclination angle of the concave groove 16 of the polishing pad 10 in consideration of the material of the polishing pad and wafer, required accuracy, and the like. In addition, the excellent polishing accuracy and polishing efficiency obtained in this way can be stably exhibited without significantly reducing the wear and dressing of the polishing pad.

  Note that if the inclination angle α of the concave groove 16 is excessively increased, a stick-slip-like phenomenon occurs and the polishing state tends to become unstable. Therefore, the value of the inclination angle α is preferably −30 degrees ≦ It is desirable to set within a range of α ≦ + 30 degrees, and more preferably within a range of −20 degrees ≦ α ≦ + 20 degrees. Further, considering the effect of improving the fluidity of the slurry due to the centrifugal force as described above, it is preferable that 0 degree <α so that the concave groove is opened toward the outer peripheral side. Moreover, since the polishing efficiency is advantageously increased by the edge effect as described above, the processing pressure of the entire pad required for achieving the desired polishing efficiency can be reduced as compared with the conventional case. . In other words, if the processing pressure is too large, the pad base material has a problem of sagging on the outer peripheral side due to the rebound resilience of the pad base material. It is possible to increase the polishing efficiency by increasing the peak pressure without depending on the increase of. Therefore, problems such as dripping on the outer peripheral side of the pad article can be reduced or solved by adopting the inclined groove 16.

  Next, another specific example of the concave groove 16 formed in the polishing pad is shown in FIGS. Each of these specific embodiments shows another form of the groove formed in the polishing pad, and has the same structure as that shown in FIGS. About a member and a site | part, the detailed description is abbreviate | omitted by attaching | subjecting the code | symbol same as what was shown by FIGS.

That is, the concave groove 42 of the polishing pad 41 shown in FIG. 12 is radially inward toward the opening side of the inner wall surface 44 and the outer wall surface 46 opposite to the concave groove 16 shown in FIG. It has an inclined surface shape that spreads out. In particular, in the present embodiment, the inclination angle: α of the inner wall surface 44 and the outer wall surface 46 with respect to the central axis 18 is a negative value and the same value, and the inner and outer wall surfaces 44 and 46 are parallel to each other. The groove 42 is formed so as to extend in the circumferential direction. In short, the groove 42 has a groove width dimension B that is substantially constant throughout.
In the concave groove 42 shown in FIG. 12, a centrifugal force acts on the slurry 28 that has entered the concave groove 42 as the polishing pad 41 rotates, so that the concave groove 42 is applied to the slurry 28. A force in the direction of pushing in is exerted. As a result, the outflow of the slurry 28 from the concave groove 42 between the opposing surfaces of the polishing pad 41 and the wafer 24 is controlled in a suppressing direction, and the slurry 28 diffused from the vicinity of the center of rotation of the polishing pad 12 to the outer peripheral side by centrifugal force. The flow of water can be adjusted.

  Further, in the groove 42 shown in FIG. 12, polishing debris that has entered the groove 42 can be positively retained at the bottom of the groove 42, and the polishing debris can be removed from the polishing pad 41 and the wafer 24. Problems caused by entering between the opposing surfaces can be effectively prevented.

  Note that the inclination angle α of the concave groove 42 is preferably set within the same absolute value range as the inclination angle α of the concave groove 16 shown in FIG. 3, and the width dimension of the concave groove 42. The depth dimension, the radial pitch, and the like are also suitably set within the same numerical range as that of the groove 16 shown in FIG.

  Furthermore, the groove 52 of the polishing pad 50 shown in FIG. 13 and the groove 56 of the polishing pad 54 shown in FIG. 14 are both formed on the surface 14 of one polishing pad 50, 54. This is an example of the inclination angle of the grooves 52 and 56: the value of α being varied in the radial direction. 13 and 14 are sectional views in the radial direction, and only the right side in the radial direction with respect to the rotation center axis 18 of the polishing pad 50 is shown, but the left side in the radial direction in FIG. With respect to the radial right side.

  Specifically, the concave groove 52 of the polishing pad 50 shown in FIG. 13 has an inner peripheral portion close to the central axis 18 and an intermediate portion in the radial direction, as shown in FIG. The groove shape is inclined toward the outer periphery of the pad as it approaches the opening, but there is a pad radial intermediate portion located radially outward from the groove 52a formed in the inner peripheral portion. The formed groove 52b has a smaller inclination angle α, and the groove 52c formed in the outer peripheral part far away from the central shaft 18 has both inner and outer wall surfaces that are the same as the central shaft 18. The value of α is reduced until a vertical groove shape rising substantially in parallel is formed, that is, until α≈0 degrees. In short, the width dimension B of the concave groove 52 is substantially constant, but the inclination angle α of the concave groove 52 is gradually reduced from the central portion to the outer peripheral portion.

  In the polishing pad 50 having such a concave groove 52, the centrifugal force acting on the slurry 28 in the concave groove 52 based on the difference in the peripheral speed at each point due to the difference in the distance from the rotation center axis 18. This difference can be reduced or eliminated by adjusting the inclination angle of the concave groove 52, and it is possible to make the inclination action of the concave groove 52 uniform over the entire surface 14 of the polishing pad 50. It becomes.

  Further, the concave groove 56 of the polishing pad 54 shown in FIG. 14 is inclined toward the outer peripheral side as approaching the opening as shown in FIG. 3 in the inner peripheral portion of the pad close to the central axis 18. The concave groove 56a is formed in the radially intermediate portion of the pad and is located radially outside of the concave groove 56a. The groove 56c is formed in the shape of a vertical groove that rises substantially in parallel, and the groove 56c formed in the outer peripheral portion of the pad that is far away from the central axis 18 is closer to the opening as shown in FIG. The groove 56c has a shape inclined toward the inner peripheral side. In short, the width dimension B of the groove 56 is substantially constant, but the inclination angle α of the groove 56 gradually increases from the + region to the − region so that the inclination angle α of the groove 56 gradually decreases from the center portion to the outer peripheral portion. It has been changed to.

  In the polishing pad 54 having such a concave groove 56, a flow that positively flows out to the slurry 28 in the concave groove 56 occurs at the inner peripheral portion where the distance from the central axis 18 that is the rotation center is small. On the other hand, in the outer peripheral portion far away from the central axis 18, it is possible to apply a flow that suppresses the outflow to the slurry 28 in the concave groove 56, and thereby, the polishing pad 10 and the wafer 24. The flow of the slurry 28 between the opposing surfaces can be controlled in consideration of the overall flow.

  Further, a large number of concave grooves 62 of the polishing pad 60 shown in FIG. 15 are linearly formed on the surface 14 of the polishing pad 60. In particular, the plurality of concave grooves 62 includes a plurality of first group of concave grooves 62a extending in parallel with each other and a plurality of second group of concave grooves 62b extending in parallel with each other. The respective concave grooves 62 a constituting the second group and the respective concave grooves 62 b constituting the second group are orthogonal to each other on the surface 14 of the polishing pad 60.

  In this embodiment, in each group, each of the plurality of concave grooves 62a and 62b that are constituent elements thereof is formed in parallel with each other at a substantially constant interval, and as a result, each of the plurality of grooves constituting the two groups. Since the concave grooves 62a and the concave grooves 62b intersect each other substantially orthogonally, a large number of concave grooves 62 are formed on the surface of the polishing pad 60 in a substantially grid pattern as a whole. .

  Further, as is apparent from the pad longitudinal sectional view shown in FIG. 16, each of the concave grooves 62 a and 62 b constituting each group is an inclined groove inclined in the depth direction with respect to the pad surface 14. Has been. In particular, the concave grooves 62 on both sides sandwiching the pad central axis 18 are set to have an inclination angle that is symmetrical to the left and right with respect to one symmetrical plane including the pad central axis 18 and a pad radial line parallel to the concave groove 62. Has been. FIG. 16 shows only the first group of grooves 62a. However, in the radial cross section orthogonal to the cross section shown in FIG. 16, only the second group of grooves 62b is shown in FIG. It will appear in the same form as shown.

  Even in the polishing pad 60 provided with such a large number of linearly extending concave grooves 62a and 62b, the wafer is polished while being rotated around the central axis 18 as shown in, for example, Patent Documents 1 to 3 described above. 1, the flow promoting action against the slurry by the inclined inner and outer wall surfaces 64, 66 of the concave grooves 62 a, 62 b, the adjustment efficiency of the polishing efficiency corresponding to the inclination angle of the concave grooves 62 a, 62 b, etc. Any of the same effects as those of the polishing pad having the circumferential grooves as shown in FIG.

  Here, in the polishing pad 60 of this embodiment as well, as in the polishing pad shown in FIG. 12, the respective concave grooves 62a and 62b are inclined so as to open radially inward. 14, the inclination angle of each of the concave grooves 62a, 62b can be set appropriately different depending on the position on the surface 14 of the polishing pad 10, thereby This makes it possible to adjust the polishing accuracy and polishing efficiency for the wafer, the flow state of the slurry, and the like.

  Further, when a groove pattern including a plurality of linearly extending concave grooves 62 as illustrated is employed, the pattern, pitch, number, group number, etc., of the polishing pad 10 on the substrate 12 can be arbitrarily set. is there. Specifically, for example, as shown in FIGS. 17 and 18, first, second, and third groove groups including a plurality of concave grooves 62 a, 62 b, 62 c extending in different directions are employed. The roughness of the mesh pattern formed by the plurality of groove groups can be arbitrarily set as is apparent from FIGS. Further, although not shown in the drawing, such a direct plurality of concave grooves 62 composed of a single group or a plurality of groups are combined with the circumferentially extending concave grooves 16 as shown in FIGS. It is also possible to form it on the surface of the polishing pad 10.

  The concave grooves 16, 42, 52, 56, 62 having various shapes as described above can be formed on the pad substrate 12 by an arbitrary method, for example, by injection molding of the polishing pad 10. It is possible to form such a concave groove at the same time, or to form it by cutting using a rotary tool 70 such as a milling tool as shown in FIG. It is formed by cutting using a cutting tool provided with a cutting blade having a shape corresponding to the cross-sectional shape of the groove.

  More specifically, for example, as shown in FIGS. 20 to 21, a multi-blade tool provided with a cutting edge 80 corresponding to the shape of the intended concave groove at an appropriate pitch: P on the leading edge. By using a cutting tool in which the multi-blade tool tip 82 is fixed to an appropriate tool holder 84 in a replaceable manner using the tip 82, the surface of the pad substrate 12 is cut to obtain the desired concave groove 16, 42, 52, 56, 62 are formed.

  Further, as shown in FIG. 21 (a), the tool holder 84 is provided with an ion blow passage 90 that extends straight through the inside, and vacuum suction is performed on the front side from which the cutting blade 80 protrudes. A device 92 is attached. More specifically, the ion blow passage 90 is connectable to an external static electricity removing air blow device at the upper end thereof, and is opened toward the protruding direction of the cutting blade 80 at the lower end thereof behind the cutting blade 80. It is supposed to be. Then, ions (hereinafter referred to as ion blow) supplied together with compressed air from an external static electricity removing air blow device are inclined at substantially the same angle as the cutting edge 80 behind the cutting edge 80 and downward. It comes to be ejected. As a result, ion blow is directly sprayed onto the pad substrate 12 cut by the cutting blade 80 or its chips (chips) and the like, and their charging is advantageously prevented. Adhesion to the groove wall can be advantageously avoided. It is desirable that the ion blow ejection direction be inclined forward in the cutting direction as shown in the figure. That is, simultaneously with the cutting of the groove on the pad substrate 12, the chips can be sent to the front of the multi-blade tool tip 82 through the gaps between the blades of the multi-blade tool tip 82, whereby the chips enter the groove of the chip. Adhesion can be prevented more advantageously. Here, various known static electricity removing air blow devices may be employed as the static electricity removing air blow device connected to the ion blow passage 90.

Further, the vacuum suction device 92 is attached in a state where the opening is opened in the vicinity of the front of the cutting blade 80, and the chips that are sequentially sent to the front of the cutting blade 80 are removed by the vacuum suction device 92. It is possible to immediately collect the suction.
In addition, as shown in FIG. 21 (b), the lower end portion of the ion blow passage 90 is inclined at substantially the same angle as the inclination angle of the cutting edge 80 with respect to the central axis 18 of the pad base material 12, Thus, the ion blow can be advantageously exerted on the inner peripheral side wall surface and the bottom surface of the inclined groove 16 that is undercut with respect to the surface of the pad base material 12, and by charging the chips on the surface. Adhesion can be advantageously prevented.

  In this case, as shown in FIG. 22 or FIG. 23, the cutting edge 80 is an angle corresponding to the inclination angle: α of the target groove 16 or the like with respect to the central axis of the tool holder 84. It is only tilted and protruding. If a cutting tool provided with such an inclined and projecting cutting edge 80 is used, the cutting edge 80 is inclined with respect to the pad substrate 12 by an inclination angle α, as shown in FIG. Attaching in the state and cutting. Specifically, the cutting edge 80 has a cutting edge 81 and side faces 83, 83 on both sides, and each side face 83 is inclined at the same inclination angle α toward the same side with respect to the cutting edge 81. Yes. Furthermore, if the cutting edge 80 is protruded by a predetermined amount in the inclined protruding direction, the process of repeatedly cutting the same cutting part to trace the same cutting site can be performed with a straight groove, a spiral groove or the like. For example, the groove 16 having an intended inclination angle: α can be obtained by repeating the cutting of the same groove a plurality of times with an intermittent mode such as a reciprocating operation, and with a continuous rotation mode if it is an annular circumferential groove. It can be cut and formed advantageously. In particular, when turning continuously in the circumferential direction to form an endless circumferential groove, the cutting height of the cutting blade 80 is cut while gradually protruding rather than every round. Also good. In this case, the cutting edge 80 functions as a groove processing tool for cutting a groove extending substantially in the circumferential direction on the surface of the pad substrate 12.

  When cutting the groove 16 or the like extending in the circumferential direction, for example, the cutting tool 80 is fixed to a lathe, and the cutting edge 80 of the multi-blade tool tip 82 is rotated while the pad substrate 12 is rotated about the central axis 18. Can be made close to the pad substrate 12 and turned as described above to efficiently form the intended groove 16 or the like. Such a turning process is described in detail in, for example, Japanese Patent Application Laid-Open No. 2001-18164 filed earlier by the present applicant, and therefore, detailed description thereof is omitted here.

  In addition, as shown in FIG. 25, the specific shape of the cutting blade 80 of the cutting tool is 0.005 in correspondence with the width of the intended groove, B, as shown in FIG. It is desirable that the angle is set within a range of 3.0 mm, the blade angle: β is 15 to 35 degrees, and the front clearance angle: γ is 65 to 45 degrees. When the front clearance angle γ is less than 45 degrees, the back portion of the cutting edge 80 is the pad substrate 12 during cutting when the front clearance angle γ is less than 45 degrees. This is because it is difficult to obtain a good grooved surface, and particularly when the circumferential groove 16 as shown in FIG. 1 is cut, the inner peripheral portion having a small curvature radius is cut. Since the rear portion of the cutting edge 80 tends to interfere with the inner surface of the groove during processing, it is important to set the front clearance angle γ of the cutting edge 80 within a range of 65 to 45 degrees. When the front clearance angle: γ exceeds 65 degrees or the blade angle: β is out of the range of 15 to 35 degrees, the rake angle: θ on the front surface of the blade is difficult to ensure and good cutting performance is obtained. This makes it difficult to secure sufficient durability and strength.

  As mentioned above, although several embodiment of this invention has been explained in full detail, these are illustrations to the last, Comprising: This invention is not interpreted limitedly by the specific description in this embodiment. . In addition, the present invention can be implemented in a mode in which various changes, corrections, improvements, and the like are added based on the knowledge of those skilled in the art, and unless such embodiments depart from the spirit of the present invention, Needless to say, both are included within the scope of the present invention.

  For example, in the present invention, in a concave groove formed in a polishing pad having various forms such as a circumferentially extending groove and a linearly extending groove formed in the polishing pad, a part or a plurality of portions of one concave groove Inclined grooves may be formed, or some or all of the plurality of concave grooves may be inclined over the entire length to form inclined grooves.

  In addition, the substantially parallel side wall surfaces in the inclined grooves employed in the present invention do not have to have the same inclination angle in a strict sense, and the required polishing accuracy, pad substrate material, wafer material, etc. In consideration, it should be understood that there is an allowable range for the parallelism of the both side walls of the inclined groove. However, if the wall surfaces on both sides of the inclined groove are inclined in different directions with respect to the center axis of the pad substrate, the polishing characteristics may change significantly with respect to pad wear and dressing. It should be understood that the substantially parallel inclined grooves in the invention are those in which both side wall surfaces of the inclined grooves are inclined in the same direction in the depth direction with respect to the central axis of the pad substrate except for such a mode.

  Furthermore, the usage form of the polishing pad having the structure according to the present invention is not limited in any way, and the polishing pad according to the present invention is used in various embodiments including a slurry supply method, including a semiconductor substrate. Needless to say, it is possible to perform polishing on various workpieces to be applied. The scope of application of the polishing pad according to the present invention is not limited to the CMP method.

  As is apparent from the above description, in the polishing pad having the structure according to the present invention, the flow of slurry and the like during the polishing can be controlled and the polishing state can be optimally adjusted by the inclination angle of the groove. It is possible to maintain substantially constant polishing conditions, and it is possible to stably polish the target high-accuracy polishing pad.

  Further, according to the method of the present invention, for example, a metal substrate is soft or narrow, and a semiconductor substrate which is extremely difficult to polish is efficiently and stably polished. It becomes possible to manufacture.

  Furthermore, according to the method for manufacturing a polishing pad according to the present invention, a polishing pad having a structure according to the present invention can be stably manufactured by providing a more accurate concave groove.

  Further, by adopting the grooving tool according to the present invention, it is possible to easily form the concave groove in the polishing pad with a smooth inner surface by turning, and the polishing according to the present invention is performed. The pad can be advantageously manufactured.

FIG. 1 is a plan view showing a polishing pad as an embodiment of the present invention. FIG. 2 is a plan view showing a polishing pad as another embodiment of the present invention. FIG. 3 is an enlarged vertical cross-sectional view of a main part showing an example of a specific structure of a concave groove employed in the polishing pad shown in FIG. 1 or FIG. FIG. 4 is a longitudinal cross-sectional explanatory view for explaining a polishing process using the polishing pad having the concave groove shown in FIG. FIG. 5 is an explanatory diagram showing simulation conditions for studying the influence of the groove width variation of the groove on the polishing pad on the polishing action. FIG. 6 is an explanatory diagram showing simulation conditions for examining the influence of the change in the inclination angle of the groove in the polishing pad on the polishing action. FIG. 7 is a graph as a simulation result showing the contact surface pressure of the wafer with respect to the polishing pad when the inclination angle of the concave groove: α = 0 degrees. FIG. 8 is a graph as a simulation result showing the contact surface pressure of the wafer with respect to the polishing pad when the inclination angle of the concave groove is α = −5 degrees. FIG. 9 is a graph as a simulation result showing the contact surface pressure of the wafer with respect to the polishing pad when the inclination angle of the concave groove is α = −10 degrees. FIG. 10 is a graph as a simulation result showing the contact surface pressure of the wafer with respect to the polishing pad when the inclination angle of the concave groove is α = + 5 degrees. FIG. 11 is a graph as a simulation result showing the contact surface pressure of the wafer with respect to the polishing pad when the inclination angle of the concave groove is α = + 10 degrees. FIG. 12 is an enlarged vertical cross-sectional view of a main part showing still another specific structural example of the concave groove suitably employed in the polishing pad shown in FIG. 1 or FIG. FIG. 13 is an enlarged vertical cross-sectional view of a main part showing still another specific structural example of the concave groove suitably employed in the polishing pad shown in FIG. 1 or FIG. FIG. 14 is an enlarged vertical cross-sectional view of a main part showing still another specific structural example of the concave groove suitably employed in the polishing pad shown in FIG. 1 or FIG. FIG. 15 is a plan view showing a polishing pad as still another embodiment of the present invention. 16 is a cross-sectional view taken along the line XVI-XVI in FIG. FIG. 17 is a plan view showing a polishing pad as still another embodiment of the present invention. FIG. 18 is a plan view showing a polishing pad as still another embodiment of the present invention. FIG. 19 is a front view showing an example of a rotary tool that can be employed when manufacturing a polishing pad having a structure according to the present invention. FIG. 20 is a front view showing an example of a cutting tool that is preferably employed when manufacturing a polishing pad having a structure according to the present invention. 21A is a side view of the cutting tool shown in FIG. 20, and FIG. 21B is an enlarged rear view of the multi-blade tool tip mounting portion in FIG. FIG. 22 is an enlarged explanatory view of a main part showing a specific example of a cutting tool that is suitably employed in the cutting of a concave groove according to the present invention. FIG. 23 is an enlarged explanatory view of a main part showing another specific example of a cutting tool that is suitably employed for cutting a groove according to the present invention. FIG. 24 is an explanatory diagram for explaining a process of cutting and forming a groove in the pad substrate using the cutting tool shown in FIG. FIG. 25 is an explanatory side view of the cutting tool shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Polishing pad 12 Pad board | substrate 14 Surface 16 Concave groove 18 Central axis 24 Wafer 80 Cutting blade 82 Multi-blade tool tip 84 Tool holder

Claims (4)

In a polishing pad used for polishing a semiconductor substrate, in which a concave groove is formed on the surface of a pad substrate made of synthetic resin,
As the concave grooves, circumferential grooves distributed over the entire polishing surface of the pad substrate and extending in the circumferential direction around the central axis of the pad substrate are separated on the radial direction line of the pad substrate and multiplexed over the entire surface of the pad substrate. The circumferential groove is an inclined groove having parallel side walls inclined in the depth direction with respect to the central axis of the pad substrate, and the groove width in the circumferential groove: B, depth: A polishing pad, wherein the values of D, pitch: P, and inclination angle: α are set within the following ranges.
0.005mm ≤ B ≤ 3.0mm
0.1mm ≤ D ≤ 2.0mm
0.1mm ≤ P ≤ 5.0mm
5 degrees ≦ | α | ≦ 30 degrees   The polishing pad according to claim 1, wherein a groove width dimension error in the inclined groove is 5% or less.   A method of manufacturing a semiconductor substrate, comprising polishing the semiconductor substrate using the polishing pad according to claim 1.   The method of manufacturing a semiconductor substrate according to claim 3, wherein the semiconductor substrate is polished while suppressing variations in polishing pressure to 2% or less.

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