WO2006003697A1 - Grinding pad and method of producing the same - Google Patents

Abstract

A grinding pad with a novel structure, and the pad has a easily formable spiral groove and is capable of being practically used in industrial fields. A central recess (28) having an outer peripheral wall surface (29) with a tubular shape is formed in the central section of a grinding surface (14), and a spiral groove (16) having a substantially constant cross- section is cut and formed in the grinding surface. The groove (16) spirally extends in the grinding surface (14) from the outer peripheral wall surface (29) of the central recess (28) toward the outer periphery side of the pad and opens at the outer peripheral edge of the pad.

Description

 Specification

 Polishing pad and manufacturing method thereof

 Technical field

 The present invention relates to a polishing pad used in a polishing apparatus that polishes and planarizes a surface of a substrate such as a semiconductor wafer in a semiconductor manufacturing process, and a method for manufacturing a polishing pad that works.

 Background art

 [0002] With the miniaturization and high integration of semiconductor integrated circuits, a Si layer having a good surface flatness for forming a flattened interlayer insulating film, a damascene structure wiring, or the like In order to form SOI (silicon on insulator) having a surface, a polishing surface of a substrate such as a semiconductor wafer is pressed against the polishing surface of a polishing pad, and a slurry composed of fine particles and liquid is interposed between the substrate and the polishing pad. A flattening technique using chemical mechanical polishing (CMP), in which the surface to be polished of the substrate is polished by the relative movement of the substrate and the polishing pad, is widely used.

[0003] By the way, in this chemical mechanical polishing method, in order to achieve high integration and high accuracy of semiconductor devices by forming a multilayer of complicated fine structure wiring, (I) the entire surface of the wafer is used. “Polishing accuracy” for polishing with high-precision planarization ability and (iii) “polishing efficiency” for polishing wafers with excellent work efficiency are required. In addition, the demands regarding both of these are becoming stronger especially in the case of higher density in recent semiconductor devices.

 [0004] In order to meet such demands, it is generally effective to keep the slurry on the polishing surface as long as possible while making the composition and layer thickness of the slurry supplied onto the polishing surface uniform. In order to realize such an effect, a polishing pad has been employed in which a grid-like groove is formed on the polishing surface so as to be orthogonal or oblique with respect to a linear groove.

However, in such a grid-like groove processing, slurry is easily discharged from the polishing surface by the action of centrifugal force caused by the rotation of the polishing pad, and the slurry cannot be held effectively. Toi There was a problem.

 [0006] Therefore, concentric circumferential grooves have been proposed in order to improve the holding force of the slurry on the polishing surface (see, for example, Patent Document 1). However, since such a circular groove does not have a portion opening on the outer periphery of the polishing pad, depending on the polishing conditions such as the rotational speed of the polishing pad and the viscosity of the slurry, the slurry in the groove may stay. Immediately after used slurry and unused slurry were not effectively circulated, and the uniformity of the slurry composition could be hindered.

 Therefore, in recent years, in order to enable the slurry to be discharged while maintaining a high level of slurry holding effect as described in Patent Document 2, it is spirally formed in the outer circumferential direction starting from the central portion of the polishing surface. An expanding spiral groove has been proposed. Such a swirl-shaped groove has a shape that expands in the circumferential direction, and its end point is opened to the outer periphery of the polishing pad, so that the slurry holding effect is maintained at a high level. It is expected that used slurry and polishing waste will be discharged effectively.

 [0008] However, the polishing pad provided with the vortex-shaped grooves as shown in the example has a problem that its manufacturing is extremely difficult.

That is, the concave grooves in the polishing pad are generally considered to be (i) formation by mold forming, (ii) formation by a milling tool, and (m) formation by end milling.

However, in (i) mold forming, it is difficult to cover a mold for forming a narrow groove, and it is difficult to obtain durability of the mold. In addition, due to the influence of the contact area with the mold, etc., there is a possibility that the original material characteristics that the pad surface is easily altered cannot be obtained. In addition, when trying to form a concave groove with a narrow width and complex shape, it becomes difficult to stably fill the molding cavity with the molding material, and in addition, it causes galling and the like during mold removal. It was difficult to completely prevent the resulting molded product from being damaged, and there was a problem that it was difficult to obtain a high dimensional accuracy as intended.

 [0011] (ii) In the milling tool, when the spiral of the inner peripheral portion having a small curvature radius is cut, the end mill comes into contact with the outer peripheral wall surface in the circumferential direction, so that the processing accuracy of the outer peripheral wall surface of the concave groove is improved. There is a problem that it falls significantly.

[0012] Further, (iii) the end mill cache has a problem that it takes too much time for processing. That is, In order to form a vortex-shaped groove by end milling, the polishing pad needs to be ground gradually while moving in the radial direction while rotating around the central axis relative to the end mill. In order to ensure accuracy, the speed of rotation and movement is extremely limited due to the characteristics of the tool used. By the way, when the present inventor conducted experiments and trial calculations using a currently available end mill, the outer diameter: D = 500 mm polishing pad:! At least 4 hours required for the vortex groove cage . In addition, it takes 10 hours to process a vortex groove on a D = 80 Omm polishing pad for a 300 mm substrate, which is disproportionate as the manufacturing cost of the polishing pad.

 (Patent Document 1)

 JP 2003-165049

 (Patent Document 2)

 Japanese Patent Laid-Open No. 2001-138212

 Disclosure of the invention

 [0013] Here, the present invention has been made in the background as described above, and the problem to be solved is that it is provided with spiral grooves that can be easily formed and is practically used in the industrial field. An object of the present invention is to provide a polishing pad having a novel structure that can be used in a practical manner.

 [0014] Another object of the present invention is to provide a novel method for producing a polishing pad, which can efficiently produce a polishing pad having spiral grooves with good practicality.

 [0015] Furthermore, the present invention provides a semiconductor substrate that can be polished with high accuracy and efficiency by using the polishing pad having a novel structure according to the present invention as described above. Another object of the present invention is to provide a novel polishing method.

 [0016] Hereinafter, embodiments of the present invention made in the background as described above will be described. Note that the constituent elements employed in each aspect described below can be employed in any combination as much as possible. Further, 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 based on thought.

(Aspect 1 of the present invention relating to polishing pad) Aspect 1 of the present invention relating to the polishing pad has a thin disk shape, and the back surface is a mounting surface that is superimposed on the rotating plate of the polishing device, while the front surface is a polishing surface that has a polishing action on the semiconductor substrate. The polishing pad is formed with a central recess having a cylindrical outer peripheral wall surface at a central portion of the polishing surface, and the polishing surface extends from the outer peripheral wall surface of the central recess toward the pad outer peripheral side. A spiral groove that extends in a vortex shape and opens at the outer peripheral edge of the pad is cut and formed with a substantially constant cross-sectional shape.

[0018] In the polishing pad having the structure according to the present embodiment, the central recess formed in the center can be used as the machining base point or the end point of the turning process, and the polishing pad having the spiral groove is cut. It becomes possible to manufacture easily. That is, when the cutting tool is moved away from the outer peripheral edge of the polishing pad toward the inner peripheral edge by turning the central recess into the inner peripheral edge, when turning, the cutting tool is moved to the inner periphery of the spiral groove. It is no longer necessary to extract it before reaching the side edge. On the other hand, when moving the cutting tool from the inner peripheral edge to the outer peripheral edge of the polishing pad, the cutting tool is moved to a predetermined depth in the central recess in advance. Since it is possible to move toward the outer peripheral edge after feeding, spiral grooves with a certain depth dimension up to the inner peripheral edge can be turned efficiently with excellent quality by turning. Can be formed as desired. As a result, a polishing pad having spiral grooves, which has been difficult to manufacture, can be efficiently manufactured with good practicality, and can be mass-produced industrially.

 [0019] Furthermore, the central recess can be used for storing slurry as a reservoir for polishing slurry supplied during polishing of the semiconductor substrate. As a result, the slurry can be more effectively held even in the central portion of the polishing pad that is likely to flow to the outer peripheral side due to the centrifugal force action, and the polishing quality can be improved.

[0020] Here, the specific shape of the central recess is not limited in any way, for example, a circumferential groove having a predetermined depth, a counterbore opened in a circular shape, or a thickness direction of the polishing pad. Various shapes, such as a through-hole penetrating, can be appropriately employed. Therefore, the cylindrical outer peripheral wall surface does not necessarily have to be formed in parallel with the axial direction of the polishing pad in the plate thickness direction. For example, it may be formed as a tapered cylindrical shape. good. As for the method of forming the central recess, it is possible to mold a polishing pad having the central recess in advance without cutting.

 [0021] Also, the specific shape of the spiral groove can be set as appropriate according to the judgment of those skilled in the art. Examples of the shape of the spiral groove include Archimedes spiral, hyperbolic spiral Examples include logarithmic spirals (so-called Bernoulli spirals). It is also possible to form a plurality of spiral grooves.

 (Aspect 2 of the present invention relating to polishing pad)

 Aspect 2 of the present invention relating to the polishing pad is the polishing pad according to aspect 1, wherein the central recess is an annular groove force extending continuously in the circumferential direction with a substantially constant width dimension. It is characterized by comprising a central annular groove. In the polishing pad having the structure according to this embodiment, the central annular concave groove as the central concave can be formed by cutting with a byte in the same manner as the spiral groove. This makes it possible to simultaneously form the central annular groove in the process of forming the spiral groove, and more efficiently the spiral groove without requiring a special process for forming the central recess in advance. It is possible to manufacture a polishing pad having

 (Aspect 3 of the present invention relating to polishing pad)

 Aspect 3 of the present invention relating to the polishing pad is the polishing pad according to aspect 1, wherein the central recess is constituted by a circular counterbore-shaped central circular recess that expands with a predetermined diameter. , Feature. In the polishing pad having the structure according to this aspect, a large amount of slurry can be stored in the central circular recess, and the central circular recess can be effectively used for supplying and discharging the slurry. That is, new slurry stored in the central circular recess is caused to flow in the outer circumferential direction by the spiral groove, and new slurry is supplied from the central circular recess to the polishing surface of the polishing pad, or the slurry is removed from the polishing pad by the spiral groove. It is possible to collect used slurry and polishing debris in the central circular recess by flowing in the center direction.

[0024] In addition, since the opening shape of the central circular recess is circular, the cutting tool can be easily inserted into and removed from the central recess in the cutting of the spiral groove, Work efficiency can also be improved. [0025] It should be noted that it is possible to form the central circular recess that is strong, by cutting, but considering the working efficiency, it should be formed by molding at the time of molding the polishing pad. Is desirable.

 [0026] Further, the specific shape of the central circular recess is not limited in any way. For example, the bottom cross-sectional shape includes not only a rectangular shape but also an upward spherical surface, a downward spherical surface, an upward conical shape, a downward conical shape, and the like. Illustrated.

 (Aspect 4 of the present invention relating to polishing pad)

 Aspect 4 of the present invention relating to the polishing pad is the polishing pad according to aspect 2 or 3, wherein the communication hole is formed through the bottom wall portion of the central recess in the pad thickness direction. Features. In the polishing pad structured according to this embodiment, new slurry can be supplied to the central recess through the communication hole, or used slurry stored in the central recess can be discharged. Further, in this embodiment, since the communication hole is formed through the bottom wall portion of the central recess, for example, the slurry supply / discharge means provided in the platen on which the polishing pad is placed and the communication hole are provided. By connecting, it is possible to supply new slurry and slurry from the bottom of the central recess, and to effectively discharge used slurry and polishing debris that stays at the bottom of the central circular recess. It is possible to stably and more effectively generate the slurry circulation in the station. The opening shape of the communication hole is not limited to a circular shape, and any shape can be adopted, and the opening size is not limited at all. For example, when the communication hole is opened in a circular shape, the diameter of the communication hole does not necessarily need to be smaller than the diameter or width of the central recess and is larger than the diameter or width of the central recess. It can also be formed and connected to the central recess. According to such an aspect, the slurry can be supplied and discharged more smoothly.

 [0028] (Aspect 5 of the present invention relating to polishing pad)

Aspect 5 of the present invention relating to the polishing pad is the polishing pad according to aspect 1, wherein the central recess is constituted by a central circular hole penetrating in the pad thickness direction with a predetermined inner diameter dimension. Is a feature. In the polishing pad having the structure according to this embodiment, the central recess can be more easily formed by, for example, punching in addition to the molding by the above-described mold formation. Furthermore, also in this embodiment, for example, a polishing pad is placed. By connecting the slurry supply / discharge means provided on the platen and the central circular hole, it is possible to supply or discharge the slurry from the bottom of the central recess, and effectively circulate the slurry in the central recess. You can squeeze.

 [0029] (Aspect 6 of the present invention relating to the polishing pad)

 Aspect 6 of the present invention relating to a polishing pad is a polishing pad according to any one of the aspects 1 to 5, wherein the spiral groove is substantially on the pad radial direction line over the entire length. It is characterized by being an interval. In the polishing pad having the structure according to this embodiment, the spiral groove is formed as a so-called Archimedes spiral, so that the groove interval of the spiral groove in the radial direction of the polishing pad is equalized. Since the polishing scrap is conveyed in the radial direction on the polishing surface and the distance to the spiral groove is the same in every part in the radial direction of the polishing pad, polishing waste flows on the polishing surface. Time can be made uniform. As a result, the composition of the slurry on the polishing surface can be made uniform by causing the polishing debris existing in each part on the polishing surface to flow into the spiral groove in approximately the same time and discharging it from the polishing surface. I can do it.

 [0030] (Aspect 7 of the present invention relating to polishing pad)

 Aspect 7 of the present invention relating to a polishing pad is a polishing pad according to any one of the aspects 1 to 5, wherein the spiral groove is a part having a different interval on the radial line of the node. It is characterized by having. In the polishing pad structured according to this embodiment, the groove spacing of the spiral groove in the radial direction of the polishing pad can be freely set, and the flow of slurry on the polishing surface or in the spiral groove Can be adjusted to a high degree. In addition, the vortex-like groove having “parts different from each other on the pad radial direction line” in this embodiment is not limited to the one that is unified as a whole like the so-called Berne 1 / f spiral, but of course the diameter. This includes a wide variety of Archimedean spirals that partially differ in coefficient depending on the direction.

 (Aspect 8 of the present invention relating to polishing pad)

Aspect 8 of the present invention relating to a polishing pad is the polishing pad according to any one of the aspects 1 to 7, wherein a plurality of the spiral concave grooves are formed without directly intersecting each other. This is a feature. In the polishing pad structured according to this embodiment, Compared to the case where a large number of spiral grooves are formed, the distance at which the slurry or polishing debris in the spiral grooves can flow to the outer peripheral edge is increased. Can be shortened. As a result, it is possible to shorten the time required for the polishing debris on the polishing surface to reach the outer periphery of the polishing pad, and to remove the polishing debris etc. more quickly.

 (Embodiment 9 of the present invention relating to polishing pad)

 Aspect 9 of the present invention relating to a polishing pad is the polishing pad according to aspect 8, wherein the central recess is formed by concentrically forming the central annular groove according to aspect 2. And the vortex-shaped grooves are formed to extend from the respective central annular grooves, so that the vortex-shaped grooves are at least more than the number of the grooves of the central annular grooves. As a whole, a plurality of strips are formed. In the polishing pad structured according to this aspect, each central annular groove can be skillfully used as a tool escape when forming a spiral groove, for example, a multi-blade having a plurality of blades By using the tool, it is possible to simultaneously form a plurality of spiral groove grooves extending from the center annular groove force.

 (Embodiment 10 of the present invention relating to polishing pad)

 Aspect 10 of the present invention relating to a polishing pad is the polishing pad according to any one of the aspects 1 to 9, wherein the central portion intersects the spiral groove on the polishing surface of the polishing pad. A curved radial groove extending in a curved shape from the outer peripheral portion to the outer peripheral portion is formed, and a radially inner end of the curved radial groove is open to the outer peripheral wall surface of the central recess. In addition, the radially outer end of the curved radial groove is open to the pad outer peripheral end surface. In the polishing pad having the structure according to the present embodiment, centrifugal force or centripetal force is effectively applied depending on the bending direction of the curved radial groove and the rotating direction of the polishing pad, thereby reducing the sludge in the curved radial groove. By effectively discharging or holding, the slurry on the polishing surface can be manipulated to a higher degree.

 (Aspect 11 of the present invention relating to polishing pad)

Aspect 11 of the present invention relating to a polishing pad is the polishing pad according to any one of the aspects 1 to 10, wherein the polishing pad has a center on the polishing surface crossing the spiral groove. Straight line diameter extending radially from the part toward the outer periphery Directional grooves are formed, the radially inner ends of the linear radial grooves are open to the outer peripheral wall surface of the central recess, and the radially outer ends of the linear radial grooves are It is characterized by opening to the outer peripheral edge of the pad. In the polishing pad having the structure according to this aspect, the centrifugal force action is effectively exerted on the slurry and the polishing debris in the linear radial groove by the radial groove extending in a direction substantially equal to the direction in which the centrifugal force action is exerted. As a result, the used slurry can be effectively discharged.

 [0035] Further, it is also possible to use this aspect and the above-described curved radial groove together. According to such an aspect, the slurry is actively held by the curved radial groove, and the linear radial direction is maintained. By actively discharging the slurry through the grooves, it becomes possible to more actively circulate the new slurry and the used slurry that are allowed to flow on the surface of the polishing pad. Furthermore, the slurry circulation effect can be adjusted to a higher degree by using the slurry discharging effect and the slurry holding effect of the spiral groove. For example, a spiral groove is formed with a shape that extends in the same direction as the rotation direction of the polishing pad from the central portion of the polishing pad toward the edge, and a vortex is formed by forming a linear radial groove. Combines the slurry retention effect of the ridge-like groove and the slurry discharge effect of the linear radial groove, or the vortex-like groove that extends in the direction opposite to the rotation direction of the polishing pad and the rotation direction of the polishing pad By forming a curved radial groove that spreads out, it is possible to more effectively circulate the slurry by combining the effect of slurry discharge by the spiral groove and the retention effect of the slurry by the curved groove. .

 (Aspect 12 of the present invention relating to polishing pad)

 Aspect 12 of the present invention relating to the polishing pad is the polishing pad according to any one of the aspects 1 to 11, wherein the outer peripheral wall surface of the central recess is inclined in the depth direction with respect to the pad central axis. It is characterized by being an inclined surface. In the polishing pad having the structure according to this embodiment, the centrifugal force accompanying the rotation of the polishing pad is positively applied as a component force corresponding to the inclination angle of the inclined groove to the slurry or the like existing in the central recess. As a result, it is possible to control the flow state of the slurry or the like existing between the semiconductor substrate such as a wafer and the polishing pad.

[0037] In this aspect, when the central recess as in aspect 2 also has an inner peripheral wall, It is desirable that the inner peripheral wall is an inclined surface having substantially the same inclination angle as the outer peripheral wall surface, and the width dimension of the central recess is made substantially constant in the depth direction. According to such an embodiment, the groove width of the central recess is kept substantially constant even when the depth of the central recess changes due to abrasion of the polishing pad accompanying the progress of polishing or dressing of the polishing pad surface. As a result, the polishing performance including the target polishing efficiency and polishing accuracy can be maintained.

 (Aspect 13 of the present invention relating to polishing pad)

 Aspect 13 of the present invention relating to a polishing pad is the polishing pad according to any one of the aspects 1 to 12, wherein at least one of both side walls in the width direction of the spiral groove is on the center axis of the node. It is characterized by being an inclined surface that is inclined in the depth direction.

. Also in the polishing pad having the structure according to this embodiment, the centrifugal force generated by the rotation of the polishing pad is applied to the slurries and the like existing in the spiral groove, as in the above-described embodiment 12, and the inclination angle of the inclined groove is set. As a result, it is possible to control the flow state of slurry or the like existing between a semiconductor substrate such as a wafer and a polishing pad.

 [0039] Further, also in this embodiment, both side walls in the width direction that maintain the polishing performance by keeping the groove width constant even when the depth of the spiral groove is changed, are substantially parallel inclined surfaces. It is desirable to form as

 [0040] (Aspect 14 of the present invention relating to polishing pad)

 Aspect 14 of the present invention relating to the polishing pad is a polishing pad according to any one of the aspects 1 to 13, wherein the through wall is formed through the bottom wall portion of the spiral groove in the pad thickness direction. Is formed. In the polishing pad having the structure according to this aspect, the slurry can be effectively supplied and discharged into the spiral groove through the powerful through hole.

[0041] Further, the through hole in this embodiment may be formed so as to be inclined with respect to the central axis of the polishing pad. As a result, the centrifugal force generated by the rotation of the polishing pad can be positively applied to the slurry in the through hole, and the slurry in the spiral groove can be supplied and discharged more effectively. In particular, in the case of forming the inclined grooves or inclined surfaces as described above, the through holes are formed with an inclination angle substantially equal to the inclination angle of the inclined grooves or inclined surfaces. By forming the slurry, the slurry can be smoothly supplied to and discharged from the inclined groove and the central recess.

 [0042] It should be noted that the formation site of the through-hole penetrating the polishing pad in the plate thickness direction is not limited to the bottom wall portion of the spiral groove, and the spiral wall is not limited to the bottom wall portion of the spiral groove. A through hole that directly opens may be formed on the polished surface where the concave groove is not formed. Further, the formation interval of the through holes in the circumferential direction can be appropriately set according to the judgment of those skilled in the art, and it may not be uniformly formed in the circumferential direction, and the number of formations in the circumferential direction may be determined by the number of polishing pads. It may be different in the radial region. Furthermore, the diameter of the through-hole is not particularly limited, and it is opened in the vortex-shaped concave structure with a diameter smaller than the width dimension of the vortex-shaped concave groove. Alternatively, it may be formed with a diameter larger than the width of the spiral groove and connected to the spiral groove.

[0043] (Embodiment 15 of the present invention relating to polishing pad)

 Aspect 15 of the present invention relating to the polishing pad is the polishing pad according to any one of the aspects 1 to 14, wherein the swirl-shaped concave groove is located inward in the depth direction from the width dimension of the opening. It is characterized in that the liquid reservoir is formed by expanding the width dimension. In the polishing pad having the structure according to this embodiment, more slurry can be stored in the spiral groove. In addition, polishing waste generated by polishing the semiconductor substrate can be effectively captured by the powerful liquid reservoir, and it is possible to prevent the polishing waste from returning to the polishing surface in the spiral groove interior force. Note that the specific shape of the liquid reservoir is not limited in any way, and various shapes can be arbitrarily adopted.For example, as a cross-sectional shape thereof, a taper shape spreading in the plate thickness direction, or inward in the depth direction. A shape with a circular cross section and an expanded width is illustrated.

 (Embodiment 1 of the present invention relating to a method for producing a polishing pad)

Aspect 1 of the present invention relating to a method for producing a polishing pad is a step of preparing a pad substrate made of a synthetic resin material having a thin disc shape when producing the polishing pad according to any one of the above aspects 1 to 15. The back surface of the pad substrate is overlapped and supported on a rigid rotating plate, and the surface of the pad substrate is rotated while rotating around the central axis of the pad substrate. A central recess turning step for forming the central recess by cutting the central portion in the circumferential direction, and the central recess and the pad outer peripheral edge while rotating the pad substrate. And a spiral groove turning process for forming the spiral groove by feeding a cutting tool in the substantially radial direction of the pad and performing cutting.

 According to the manufacturing method of this embodiment, a polishing pad having a spiral groove having a structure according to the present invention as described above can be efficiently manufactured with good practicality. In other words, by forming a central recess that serves as a tool escape by a central recess turning process that forms a central recess, a vortex-shaped concave groove having a constant depth dimension up to the edge is increased by cutting. It can be easily formed with accuracy.

 [0046] It should be noted that the cutting blade may be fed in any direction in the vortex-like concave groove turning process. Central concave force may be fed toward the outer peripheral edge of the polishing pad, or the outer peripheral edge of the polishing pad. You may send it from the center towards the central recess.

 [0047] Further, the central recess turning process and the spiral groove driving process may be performed continuously using the same cutting tool, or these processes may be performed separately using different cutting tools. good.

 [0048] Furthermore, as the order of the central recess turning process and the spiral groove driving process, any process may be performed first. That is, the central recess turning process is performed first, the central recess is turned in a state in which the cutting blade cannot be moved in the radial direction, and then the cutting blade is moved radially outward to form a vortex-like concave groove. Alternatively, the turning groove groove turning process is first performed, turning from the outer peripheral edge of the polishing pad toward the central portion, and finally the radial movement of the cutting tool is stopped. A central recess may be formed by turning in this state. As a result, turning force of the spiral groove with a constant depth over the entire length is positive.

[0049] In addition, when the wall surface of the central recess or the spiral groove is formed as an inclined surface as described above, the cutting blade is inclined at the inclination angle of the inclined surface in the central recess turning process or the spiral groove turning process. By making the cutting process while gradually feeding in the direction of inclination with respect to the surface of the polishing pad in a state where the surface is in contact with the surface of the polishing pad at the same angle, an inclined surface which is strong can be formed advantageously. Here, in order to bring the cutting tool into contact with the surface of the polishing pad at a predetermined angle and feed it in an inclined direction, the cutting tool is provided. The obtained cutting tool itself may be brought into contact with the polishing pad in an inclined state, or a cutting tool in which a cutting blade is attached with a predetermined inclination angle may be used.

 (Aspect 2 of the present invention relating to a method for producing a polishing pad)

 Aspect 2 of the present invention relating to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to aspect 1, wherein when the polishing pad according to aspect 9 is manufactured, a plurality of the pads are parallel to the cutting direction. By using a multi-blade tool provided with a blade as the cutting blade, a plurality of central annular grooves are simultaneously formed in the central recess turning step, and a plurality of central annular grooves are formed in the spiral concave groove turning step. It is characterized in that the spiral groove of the strip is formed at the same time. According to the manufacturing method of this aspect, it is possible to more efficiently manufacture a polishing pad having multiple spiral grooves. In this manufacturing method, it is also possible to form the inclined groove as described above by inclining the multi-blade tool itself, or by using a multi-blade tool having the blade portion itself having a predetermined inclination angle. .

 [0051] (Aspect 3 of the present invention relating to a method for producing a polishing pad)

 Aspect 3 of the present invention relating to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to aspect 1 or 2, wherein the pad substrate is rotated when the polishing pad according to aspect 10 is manufactured. Then, the curved radial groove is formed by performing cutting by sending a cutting blade in a substantially pad radial direction between the central recess formed by the central recess turning step and the pad outer peripheral edge. It is characterized by including a curved radial groove turning process. According to the manufacturing method of this aspect, it is possible to advantageously form a curved radial groove having a constant depth dimension over the entire length. Also in this embodiment, the feed direction in the radial direction of the cutting blade may be any of the center partial force of the polishing pad, the direction toward the edge, the direction of force, and the direction of force from the edge to the center.

 [0052] (Aspect 4 of the present invention relating to a method for producing a polishing pad)

Aspect 4 of the present invention relating to a method for producing a polishing pad is a method for producing a polishing pad according to any one of the aspects 1 to 3, wherein the pad substrate is produced when the polishing pad according to aspect 11 is produced. The cutting tool is substantially padded between the central recess formed by the central recess turning step and the pad outer peripheral edge under the condition that the tool is supported in a fixed position. It includes a linear radial groove cutting step of forming the linear radial groove by cutting it in the radial direction of the lid. According to the manufacturing method of this aspect, a linear radial groove having a constant depth dimension over the entire length can be advantageously formed. Also in this embodiment, the feed direction in the radial direction of the cutting blade may be any of a directional force direction from the central portion of the polishing pad to the edge portion and a directional force direction from the edge portion to the central portion.

 (Embodiment 5 of the present invention relating to a method for producing a polishing pad)

 Aspect 5 of the present invention relating to a method for producing a polishing pad is a method for producing a polishing pad according to any one of aspects 1 to 4, wherein the pad substrate is produced when the polishing pad according to aspect 14 is produced. It includes a drilling step of forming the through-hole by performing a drilling process in the plate thickness direction under the condition that is supported in a fixed position. According to the manufacturing method of this aspect, a through-hole penetrating in the thickness direction of the polishing pad can be easily formed. In particular, when the wall of the above-described central recess or spiral groove is formed as an inclined surface having a predetermined inclination angle, the drilling tool is inclined with respect to the surface of the polishing pad equal to the inclination angle of the inclined surface. By drilling at an angle, a through hole having an inclination angle equal to the inclined surface can be easily formed.

 [0054] In the present manufacturing method, it is more preferable to perform the perforating step from the mounting surface side.

 According to such an embodiment, the risk of damaging the polished surface by the perforation cage can be reduced.

 [0055] Further, the order of the above-mentioned central concave groove turning process and spiral concave groove turning process and the turning process in this embodiment can be appropriately selected according to the judgment of those skilled in the art. After forming the central recess or spiral groove by the concave groove turning process, the through hole may be formed so as to connect to the central recess or spiral groove, or the through hole is formed in advance. Then, a central recess or a spiral groove may be formed so as to be connected to the through hole.

 (Aspect 6 of the present invention relating to a method for producing a polishing pad)

Aspect 6 of the present invention relating to a method for manufacturing a polishing pad is a method for manufacturing a polishing pad according to any one of the aspects 1 to 5, wherein the spiral pad is manufactured when the polishing pad according to aspect 15 is manufactured. The spiral shape with a constant groove width formed by a concave groove turning process A liquid reservoir that forms the liquid reservoir by inserting a cutting blade into the concave groove and rotating the pad substrate while feeding the cutting blade in the radial direction of the pad substrate to perform cutting. It includes a forming step. According to this manufacturing method, it becomes possible to feed the cutting blade so as to trace the spiral groove, and the liquid reservoir expanded to have a predetermined width dimension with respect to the spiral groove extending in a spiral shape. The part can be easily formed with high accuracy. In this manufacturing method, in order to feed the cutting tool in the radial direction of the polishing pad, the cutting tool is inserted into the lower part of the swirl-shaped concave groove in advance and then fed in the radial direction to form the swirl-shaped concave groove. It may be widened or may be gradually cut in the thickness direction from the surface of the polishing pad to feed the spiral concave groove in the radial direction while widening the spiral groove. Needless to say, the cutting blade can be fed in any direction in the radial direction. Needless to say, the center partial force of the polishing pad also feeds the cutting blade in the direction of the edge, so that the outer peripheral side wall of the spiral groove is formed. It may be widened, or it may be sent from the edge side to the center portion to widen the inner peripheral side wall, and both sides may be fed together to widen both side walls.

 (Embodiment 1 of the present invention relating to a method for polishing a semiconductor substrate)

 A first aspect of the present invention relating to a method for polishing a semiconductor substrate is a method for polishing a semiconductor substrate using the polishing pad according to any one of the aspects 1 to 15, wherein the polishing pad is removed from the mounting surface side. A polishing operation is performed on the semiconductor substrate as a workpiece on the polishing surface while supporting and rotating around the rotation center axis and supplying a polishing slurry to the spiral groove through the central recess. It is characterized by exerting.

[0058] In the polishing method according to this embodiment, the slurry can be effectively supplied to the spiral groove by using the polishing pad having the structure according to the present invention. That is, since the inner peripheral side end of the spiral groove is opened and communicated with the central recess, the slurry can be smoothly supplied to the spiral groove through the central recess. is there. In addition, since the spiral groove has a shape extending in the circumferential direction, it is possible to supply the slurry evenly in the circumferential direction of the polishing pad and to form a slurry film having a small layer thickness with a small amount of slurry. I can do it. As a result, the excellent slurry supply and discharge effect by the spiral groove can be more effectively exhibited, and the target semiconductor substrate can be manufactured with excellent polishing accuracy and polishing efficiency. In addition, because it has a spiral groove, the viscosity of the slurry and the requirements The polishing characteristics can be adjusted with a large degree of freedom of adjustment by adjusting the rotation direction and rotation speed of the polishing pad in consideration of the polishing performance and the like.

 [0059] Further, in the present polishing method, when the polishing pad provided with the curved radial groove or the linear radial groove is used, the curved radial groove or the linear radial groove is also opened to the central recess. It is effective to use any of these spiral grooves, curved radial grooves, and linear radial grooves to communicate with the central recess. Slurry can be supplied.

 [0060] As the polishing pad used in the present polishing method, the polishing pad according to any of the above-mentioned embodiments can be adopted, and in particular, the central recess has a circular counterbore-shaped central circular recess. The polishing pad having the structure according to the above-described aspect 3 and the polishing pad having the structure according to the above-described aspect 5 configured by a central circular hole are preferable. In the polishing pad having the central recess having such a shape, a large amount of slurry can be stored in the central recess, and the spiral groove and the radial groove communicating with the central recess can stably stabilize the slurry. Can be supplied.

 (Aspect 2 of the present invention relating to a method for polishing a semiconductor substrate)

 A second aspect of the present invention relating to a method for polishing a semiconductor substrate is a method for polishing a semiconductor substrate using the polishing pad according to any one of the aspects 1 to 15, wherein the polishing pad is disposed from the mounting surface side. It is supported and rotated on the polishing surface by rotating in the same direction as the direction of the vortex facing the central portion from the outer peripheral edge of the polishing pad of the spiral groove around the rotation center axis. The polishing slurry is caused to flow to the central recess, and a polishing action is exerted on the semiconductor substrate as a workpiece on the polishing surface.

[0062] In the polishing method according to this embodiment, by using the polishing pad having the structure according to the present invention, the slurry flowing through the spiral groove can be effectively collected in the central recess. In other words, the peripheral edge force of the polishing pad in the spiral groove is directed to the center part. By rotating the polishing pad in the same direction as the direction of the spiral, centripetal force action is exerted on the slurry existing in the spiral groove. Can flow into the central recess. This increases the holding power of the slurry, and collects used slurry and polishing debris in the central recess, allowing the Can be effectively discharged.

 [0063] Also, the polishing pad used in the present polishing method has a polishing groove provided with a curved radial groove extending in the same direction as the spiral direction of the spiral concave groove, along with the spiral partial groove, as well as the spiral concave groove. When a polishing pad is used, since any of these grooves is openly connected to the central recess, used slurry and polishing debris can be stably collected in the central recess.

 [0064] As the polishing pad used in the present polishing method, a polishing pad according to any of the above-mentioned embodiments can be adopted, but more used slurry and polishing debris flowing into the central recess are used. Since the central recess can be stored, the shape of the central recess is a circular counterbore-shaped central circular recess. According to the above-mentioned aspect 5 configured by the polishing pad having the structure according to the above aspect 3 or the central circular hole It is preferable to use a polishing pad having a structure, particularly a polishing pad having a structure according to the fifth aspect, and a central recess provided with the through hole and penetrated in the plate thickness direction. When a polishing pad is used, it is possible to discharge the slurry collected in the central recess to the force on the mounting pad side.

 Brief Description of Drawings

FIG. 1 is a plan view showing a polishing pad as a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the polishing pad shown in FIG. FIG. 3 is an explanatory diagram for explaining a process of cutting and forming a central recess and a spiral groove in a pad substrate using a cutting tool. FIG. 4 is an explanatory diagram for explaining a process of forming a communication hole in the pad substrate using a drilling tool. FIG. 5 is a schematic cross-sectional view showing an outline of a polishing apparatus that can be suitably used in the present invention. FIG. 6 is a plan view showing a polishing pad as a second embodiment of the present invention. FIG. 7 is a plan view showing a polishing pad as a third embodiment of the present invention. FIG. 8 is an enlarged schematic cross-sectional view of a main part of the polishing pad shown in FIG. FIG. 9 is an enlarged schematic cross-sectional view of a main part showing a different aspect of the polishing pad shown in FIG. FIG. 10 is an enlarged schematic cross-sectional view of a main part showing a different aspect of the polishing pad shown in FIG. FIG. 11 is an enlarged schematic cross-sectional view of a main part showing a different mode of the polishing pad shown in FIG. FIG. 12 is an enlarged schematic cross-sectional view of a main part showing a different aspect of the polishing pad shown in FIG. FIG. 13 is a plan view showing a polishing pad as a fourth embodiment of the present invention. FIG. 14 is an enlarged schematic cross-sectional view of a main part of the polishing pad shown in FIG. FIG. 15 shows the fifth aspect of the present invention. It is a top view which shows the polishing pad as embodiment of this. FIG. 16 is a plan view showing a polishing pad as a sixth embodiment of the present invention. FIG. 17 is a plan view showing a polishing pad as a seventh embodiment of the present invention. FIG. 18 is a plan view showing a polishing pad as an eighth embodiment of the present invention. FIG. 19 is a schematic cross-sectional view showing a liquid reservoir of the present invention. FIG. 20 is an explanatory diagram for explaining a process of cutting and forming a liquid reservoir in a spiral groove using a cutting tool. FIG. 21 is an explanatory diagram for explaining a process of a different mode in which a liquid reservoir is cut and formed in a spiral groove using a cutting tool. FIG. 22 is a plan view showing still another embodiment of the polishing pad 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 preferably employed in the cutting process of the spiral groove according to the present invention. FIG. 24 is a plan view showing a different aspect of the communication hole in the first embodiment. FIG. 25 is a schematic sectional view showing the communication hole shown in FIG. FIG. 26 is a schematic cross-sectional view showing still another aspect of the liquid reservoir in the present invention. FIG. 27 is a schematic sectional view showing still another embodiment of the liquid reservoir in the present invention. FIG. 28 is a schematic cross-sectional view showing still another aspect of the liquid reservoir in the present invention. FIG. 29 is a schematic cross-sectional view showing still another aspect of the liquid reservoir in the present invention. FIG. 30 is a schematic sectional view showing a further different aspect of the liquid reservoir in the present invention. FIG. 31 is a schematic cross-sectional view showing a further different aspect of the liquid reservoir in the present invention. FIG. 32 is a schematic cross-sectional view showing still another aspect of the liquid reservoir in the present invention. FIG. 33 is a schematic cross-sectional view showing still another aspect of the liquid reservoir in the present invention. FIG. 34 is a schematic cross-sectional view showing still another aspect of the liquid reservoir in the present invention.

 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 and FIG. 2 show a polishing pad 10 as a first embodiment of the present invention. FIG. 1 is a plan view of the polishing pad 10, and FIG. 2 is a schematic diagram of a partially enlarged cross section of the polishing pad 10. The polishing pad 10 is formed of a thin disk-shaped pad substrate 12 having a constant pressure dimension as a whole. The pad substrate 12 is made of, for example, hard foamed or unfoamed urethane, silicon rubber, hard rubber, polytetrafluoroethylene, nylon. It is advantageously formed by materials selected from, for example, vinyl chloride and mixtures thereof. Note that the pressure dimension of the pad is not limited, and is appropriately set according to the material of the pad substrate 12, the material of the wafer to be processed, the required processing accuracy, and the like. In each attached drawing, the shape and scale are exaggerated in order to facilitate understanding of the shape of the spiral groove 16 and the central groove 28 described below. .

 [0068] Then, on the surface 14 as a polishing surface, which is one surface of the pad substrate 12, there is a spiral groove 16 as a spiral concave groove extending spirally toward the outer peripheral edge side of the central partial force of the pad substrate 12. Formed and open to the surface 14.

 [0069] As shown in FIG. 2, the vortex groove 16 is formed in a spiral shape (so-called Archimedes spiral) in which the radial pitch P is substantially equal in the radial direction. However, the inclined surface is inclined at a predetermined angle with respect to the central axis 18 of the pad substrate 12 over the entire length: an angle (crossing angle with respect to a straight line parallel to the central axis 18). In particular, in this embodiment, the inner wall surface and the outer wall surface are parallel to each other, and the width of the entire swirl groove 16 is substantially constant not only in the circumferential direction of the swirl groove 16 but also in the depth direction. Dimension: B, and the vortex groove 16 is gradually separated from the central axis 18 as it goes to the opening, and opens toward the outer side of the pad substrate 12 in the radial direction.

 [0070] Further, specific set values such as the size and inclination angle of each part of the vortex groove 16 are not limited to the material, thickness dimension, and outer diameter dimension of the pad substrate 12, but to the material of the wafer to be polished and the wafer. It is determined by comprehensively considering the shape and material of the formed metal wire, the required polishing accuracy, etc., and is not particularly limited, but generally the groove width of the spiral groove 16: B , Depth: D, Radial Pitch: P and Inclination Angle: α should be set within the following ranges.

 [0071] 0. 005mm ≤ B ≤ 3. Omm

 0. lmm ≤ D ≤ 2. Omm

 0. lmm ≤ P ≤ 3. Omm

 0. 5 degrees ≤ H ≤ 30 degrees

[0072] More preferably, it is set within the following range.

0. 005mm ≤ B ≤ 2. Omm (Even more preferably, 0 · 005mm ≤ B ≤ 1.0mm)

 0. lmm ≥ D 丄. 0mm

 0. 2mm ≤ P ≤ 2.0mm

 1. 0 degree ≤ sun ≤ 20 degree

 (Even more preferably, 1. 0 degrees ≤ H ≤ 15 degrees)

[0073] When the groove width of the swirl groove 16: B is too small, the flow control effect of the slurry due to the formation of the swirl groove 16 is difficult to be exerted. The spiral groove 16 is easily clogged, and it is difficult to achieve a stable effect. On the other hand, if the groove width of the spiral groove 16 is too large, the wafer at the edge portion (opening edge) of the spiral groove 16 This is because it is difficult to achieve stable polishing that easily causes bite-like polishing or the like due to an increase in contact surface pressure.

[0074] In addition, if the groove depth D of the vortex groove 16 is too small, the slurry flow effect due to the formation of the inclined vortex groove 16 is difficult to be exerted. The surface 14 is so stiff that the contact surface pressure with the wafer becomes uniform as a whole, and the contact surface pressure with the wafer at the edge of the vortex groove 16 does not increase sufficiently, making effective polishing difficult. is there. On the other hand, if the groove depth D of the vortex groove 16 is too large, the surface 14 of the polishing pad 10 is likely to be deformed, and there is a risk of stick-slip, making the polishing unstable.

Furthermore, if the radial pitch P of the vortex groove 16 is too small, the surface 14 of the polishing pad 10 is likely to be deformed or damaged, and stable polishing is difficult to be realized. On the other hand, if the pitch P in the radial direction of the spiral groove 16 is too large, it is difficult to exert the slurry flow control effect due to the formation of the spiral groove 16.

 [0076] Furthermore, if the inclination angle a of both side walls is too small, the slurry flow control effect due to centrifugal force tends to be difficult to be exhibited. On the other hand, if the inclination angle of both side wall surfaces is too large, the strength of the side wall portion of the spiral groove 16 is lowered and the surface pressure distribution becomes difficult to stabilize, and the durability of the polishing pad 10 is not sufficiently obtained. There is a risk.

In addition, a slurry circulation hole 20 is formed in the bottom wall portion of the swirl groove 16 as a plurality of through holes that are formed through the pad substrate 12 in the plate thickness direction. The slurry flow hole 20 is circular and is opened to the surface 14 side, and the other opening is the pad base. An opening is formed in the back surface 22 as a mounting surface of the plate 12. In particular, in the present embodiment, the slurry circulation hole 20 has an inclination angle of the swirl groove 16: the same inclination angle, and an inclination hole having a circular cross section penetrating with a constant diameter dimension: φ b in the thickness direction of the pad substrate 12. It has been done. The diameter dimension b of the slurry circulation hole 20 is smaller than the groove width B of the swirl groove 16. In addition, as is apparent from FIG. 2, it opens directly on the surface 14 without opening at the bottom of the vortex groove 16 at an appropriate portion on the surface 14 of the pad substrate 12 so as not to overlap with the vortex groove 16. It is also possible to form the slurry flow hole 20.

 The vortex groove 16 having such a structure has an outer peripheral side end 24 opened at an outer peripheral end edge of the pad substrate 12, while an inner peripheral side end 26 has a pad substrate. Opened in a central groove 28 as a central annular groove formed in the central portion of 12.

 The central concave groove 28 is formed in the central portion of the pad substrate 12 as an annular peripheral groove having a concentric shape with respect to the pad substrate 12 and continuously extending with a constant width in the circumferential direction. As shown in FIG. 2, both the inner peripheral wall surface and the outer peripheral wall surface 29 of the central concave groove 28 are also formed as inclined surfaces having a predetermined inclination angle. The cross-sectional shape of the groove 28 is substantially the same as that of the spiral groove 16, and the width dimension, the inclination angle, the depth dimension, and the like thereof are substantially equal to those of the spiral groove 16. As shown by this force, a central recess having a cylindrical outer peripheral wall surface is formed by the central concave groove 28, and the inner surface of the swirl groove 16 is formed on the outer peripheral wall surface 29 of the powerful central concave groove 28. The peripheral end 26 is open. Further, in this embodiment, the opening edge 31 of the outer peripheral wall surface 29 is chamfered in order to reduce slurry flow control and pulling force when a cutting tool is put in and out in the polishing pad manufacturing process described later. Is given.

[0080] Further, a plurality of slurry supply holes 30 serving as communication holes are formed in the central concave groove 28 so as to open on the bottom surface. The slurry supply hole 30 is formed so as to penetrate in the same direction as the axial direction of the pad substrate 12 with a certain diameter dimension: c, and is formed to open in a circular shape on the bottom surface of the central concave groove 28, while the other The opening is a communication hole having a circular cross section opened on the back surface 22 of the pad substrate 12. In the present embodiment, the diameter dimension c ^ c of the slurry supply hole 30 is smaller than the width dimension of the central groove 28. The slurry supply hole 30 can also be formed as an inclined hole having a predetermined inclination angle. [0081] It should be noted that the formation position and the number of the slurry circulation holes 20 and the slurry supply holes 30 can be arbitrarily set, and the distribution density and the like in each region in the circumferential direction are not limited in any way. It can be formed with uniform or non-uniform distribution density depending on the polishing characteristics and the like. Further, the circumferential length varies depending on the radial position of the node substrate 12, and the number of the slurry circulation holes 20 per unit angle around the central axis may be varied depending on the radial position.

 The polishing pad 10 having the vortex groove 16 and the central groove 28 as described above is obtained by using a turning tool having a cutting edge having a shape corresponding to the cross-sectional shape of the target vortex groove. It can be easily formed by turning according to the following manufacturing method.

 First, a pad substrate 12 having a thin disk shape and having no grooves is prepared. For this pad substrate 12, various conventionally known methods such as injection molding and mold molding can be appropriately employed.

Next, a central concave turning process for forming the central concave groove 28 is performed. In order to perform the central recess turning process, for example, as shown in FIG. 3, a cutting tool is prepared in which a cutting blade 32 corresponding to the cross-sectional shape of the target central concave groove 28 is replaceably mounted. The cutting edge 32 is provided so as to be inclined with respect to the central axis of the cutting tool by an angle corresponding to an inclination angle of the target central groove 28: _α .

 Then, as shown in FIG. 3 (a), the back surface of the pad substrate 12 is overlapped with and supported by a rigid rotation plate (not shown), and is rotated about the central axis 18. Then, the cutting blade 32 is brought close to and brought into contact with the rotated pad substrate 12. Here, by using the cutting edge 32 having the specific shape as described above, the cutting edge 32 is abutted in a state inclined by an inclination angle: α to perform cutting, and further, the protruding direction in which the cutting edge 32 is inclined. The center groove 28 with the desired cross-sectional shape is advantageous by repeating a turning process that repeatedly cuts the same cutting site so as to trace the same cutting portion with a predetermined amount greatly protruding in a continuous corridor form. Can be formed. Since the central concave groove 28 is an endless peripheral groove, in this process, the cutting height of the cutting blade 32 is cut while gradually protruding rather than every rotation of the pad substrate 12. Also good.

Next, a spiral groove turning process for forming the spiral groove 16 is performed. Spiral groove turning For example, as shown in FIG. 3 (b), the pad substrate 12 is rotated while the pad substrate 12 is rotated by inserting the cutting blade 32 into the central concave groove 28 formed by the central recess turning process to a predetermined amount. Feed it radially outward. As a result, the pad substrate 12 can be cut into a vortex shape. Similar to the above-described central recess turning process, the spiral groove 16 having a predetermined depth dimension can be advantageously formed by repeating a plurality of turning processes that repeatedly cut so as to trace the same cutting site. I can do it. Further, in the present embodiment, by using the cutting blade 32 having the inclination angle: flutes, the vortex groove 16 having a predetermined inclination angle: flutes can be advantageously formed.

 [0087] According to such a manufacturing method, since the central concave groove 28 is formed, the inner peripheral side end portion 26 of the vortex groove 16 serving as a base point of the cutting is cut to a desired depth dimension. Cutting can be started with the blade 32 inserted. As a result, it is possible to easily form a spiral groove having a certain depth dimension up to the inner peripheral side end portion 26 while achieving high machining quality by turning.

 [0088] It is also possible to form the spiral groove by feeding the cutting edge 32 from the outer peripheral surface of the pad substrate 12 to the inner peripheral portion in the spiral groove recess turning step. According to such an embodiment, the central concave groove 28 can be used as a tool escape, and the vortex groove 16 having a certain width dimension can be formed up to the inner peripheral side end portion 26.

 Further, in the present embodiment, by using the same cutting edge 32 through the central recess turning process and the spiral groove driving process, the central groove 28 having substantially the same cross-sectional shape and Although the manufacturing method for forming the spiral groove 16 has been shown, by replacing the cutting edge when the central recess turning process is completed, the cutting grooves having different shapes are used in the respective processes. It is also possible to form the spiral groove 16 with different shapes.

[0090] As described above, the central concave turning process and the spiral concave groove turning process, which are not performed after the central concave turning process is completed, are performed simultaneously. Thus, the central concave groove 28 and the swirl groove 16 can be formed simultaneously. In other words, a predetermined amount of the cutting blade 32 is abutted against the part of the rotating pad substrate 12 where the central groove 28 is formed, and the central groove 28 is formed by rotation of the pad substrate 12. After applying the groove force, the cutting blade 32 is fed in the radially outward direction. A vortex-shaped groove that forms the vortex groove 16 is formed by cutting. Then, by repeating the powerful cutting process and repeatedly tracing the cutting site while increasing the cutting depth, the central concave groove 18 and the vortex groove 16 having a desired depth dimension can be formed simultaneously. Even in such an embodiment, since the central concave groove 18 has an endless shape in the circumferential direction, first, the cutting edge 32 is abutted to a desired depth dimension, and then feeding in the radial direction is performed. You can start. In this embodiment as well, it is possible to feed the cutting edge 32 from the outer peripheral surface of the pad substrate 12 toward the inner peripheral side in the vortex-like concave groove turning process.

Furthermore, when forming the slurry circulation hole 20 and the slurry supply hole 30 as in the present embodiment, a drilling process using a drill 34 as a drilling tool as shown in FIG. 4 is advantageously employed. The axis of the drill 34 is inclined with respect to the vertical direction at an angle equal to the inclination angle of the vortex groove 16: one so as to abut against the bottom surface of the vortex groove 16. Then, the drill 34 is fed in the axial direction at such an inclination angle so as to penetrate the pad substrate 12 and form the slurry circulation hole 20 having an inclination angle _α substantially equal to the swirl groove 16. The slurry supply hole 30 can be formed by drilling perpendicularly to the bottom surface of the central groove 28 without giving an inclination angle to the powerful drill 34.

 The polishing pad 10 provided with such vortex grooves 16 is used for polishing a wafer or the like in substantially the same manner as in the past. Specifically, for example, a polishing apparatus 36 as shown in FIG. 5 can be suitably employed. The polishing apparatus 36 includes a platen 38 as a polishing platen. The platen 38 is provided with a fixing surface 40 to which the polishing pad 10 is fixed with a suitable elastic pad or by being directly overlapped, and the polishing pad 10 is attached to the forceful fixing surface 40 with tape, adhesive, or It is fixed on the mounting surface side by means such as negative pressure suction. The platen 38 is connected to a platen motor 42 as a rotation driving means, and is driven to rotate about the central axis.

Here, a slurry supply communication groove 44 as a slurry introduction hole is formed in the platen 38 so as to open to the fixing surface 40. The slurry supply communication groove 44 is formed on the fixing surface 40 of the platen 38 in the circumferential direction with a slightly larger width dimension than the slurry flow hole 20 of the polishing pad 10 and the back side opening of the slurry supply hole 30. A plurality of concentric circular shapes are formed. A slurry supply flow path 46 as a slurry supply means formed in the platen 38 is formed in an open portion and connected to an appropriate portion of the bottom surface of the slurry supply communication groove 44. The slurry supply channel 46 is an internal space formed in the platen 38, and the slurry stored in the slurry tank 50 is filled inside by the supply pump 48.

 [0094] In addition to the slurry supply communication groove 44 and the slurry supply flow path 46, the platen 38 is formed with a slurry discharge communication groove 52 as a slurry outlet hole and a slurry discharge flow path 54 as a slurry discharge means. ing. The slurry discharge communication groove 52 and the slurry discharge flow path 54 have substantially the same structure as the slurry supply communication groove 44 and the slurry supply flow path 46, respectively, and are independent slurry discharges that are not connected to the slurry supply flow path 46. Forming a flow path for use. Also, the slurry in the slurry discharge channel 54 is forced to be discharged by being sucked by the discharge pump 56. The force discharge pump 56 is not necessarily required, but it is left to drop due to its own weight. Even if you do it, good.

 Then, the polishing pad 10 is overlaid on the fixed surface 40 of the platen 38, and the slurry supply communication groove 44 and the slurry discharge communication groove 52 of the platen 38, and the slurry distribution hole 20no of the polishing pad 10 are the slurry supply holes. 30 is connected. It is not always necessary that all the slurry supply communication groove 44 and the slurry discharge communication groove 52 are connected to each other, and the slurry circulation hole 20 and the slurry supply hole 30 of the polishing pad 10 are connected to each other. The openings of the slurry supply communication groove 44, the slurry discharge communication groove 52, the slurry circulation hole 20, and the slurry supply hole 30 that are not connected to each other are formed by the overlapping polishing pads 10 or the fixing surface 40 of the platen 38. It will be covered. Incidentally, the opening shape of the slurry supply communication groove 44 and the slurry discharge communication groove 52 on the fixing surface 40 is not limited, but when the polishing pad 10 is overlapped with the fixing surface 40 of the platen 38, Since the circumferential alignment of the slurry supply communication groove 44 and the slurry discharge communication groove 52 with the slurry circulation hole 20 and the slurry supply hole 30 of the polishing pad 10 is unnecessary, the circumferential direction as in this embodiment is not necessary. Preferably, it is formed with concentric circles extending in the direction of the circle.

On the other hand, a substrate support 58 is disposed above the platen 38, and the substrate support 58 can be displaced relative to the platen 38 in the approach / separation direction. Further, a wafer 60 which is a semiconductor substrate is superimposed on the surface of the substrate support table 58 facing the platen 38. The substrate support 58 is rotationally driven by the support motor 62. As a result, the polishing pad 10 fixed to the platen 38 and the wafer 60 supported by the substrate support 58 can be rotated relative to each other. In addition, the arrow which shows the rotation direction in a figure is an illustration to the last, Comprising: The rotation direction is not limited at all.

 [0097] With such a polishing apparatus 36, the polishing pad 10 is subjected to a polishing process. In such a polishing process, as in the prior art, generally, the polishing pad 10 and the wafer 60 are rotated about their rotation center axes, respectively, so that the surface 14 of the polishing pad 10 and the wafer 60 are covered. The force by which slurry is supplied between the opposing surfaces of the carved surface The polishing pad 10 in the present invention has the vortex groove 16 that spreads in a vortex shape. It is possible to enhance the slurry discharge effect and the slurry retention effect. Specifically, by rotating the polishing pad 10 in a direction opposite to the direction of the vortex vortex from the inner peripheral end 26 of the vortex groove 16 to the outer peripheral end 24, the slurry is removed from the polishing pad 10. While it is possible to enhance the slurry discharge effect that flows to the outer peripheral side, the counter force from the inner peripheral end 26 to the outer peripheral end 24 of the swirl groove 16 is to rotate the polishing pad 10 in the same direction as the direction of the spiral. Thus, the slurry can be caused to flow toward the inner peripheral side of the polishing pad 10 to enhance the slurry holding effect. In this polishing method, the polishing pad 10 is rotated in the direction opposite to the direction of the vortex from the inner peripheral end 26 to the outer peripheral end 24 of the swirl groove 16, thereby reducing the slurry discharging effect. It is designed to increase.

 Here, the slurry supplied to the space between the surface 14 of the polishing pad 10 and the surface to be processed of the wafer 60 is continuously or intermittently pumped and supplied from the slurry tank 50 by the supply pump 48. Then, the slurry supply passage 46 formed in the platen 38 is supplied onto the surface 14 of the polishing pad 10 through the slurry supply communication groove 44 and the slurry distribution hole 20 or the slurry supply hole 30 to which the slurry supply communication groove 44 is connected. It has come to be.

Then, the polishing pad 10 having the structure according to the present invention has the central concave groove 28, so that the slurry supplied from the slurry supply hole 30 can be stored in the central concave groove 28. As a result, a sufficient amount of slurry can be supplied even in the central portion of the polishing pad 10 where it is difficult for the slurry to stay due to the centrifugal force generated by the rotational operation of the polishing pad 10, and the slurry on the periphery can be supplied. Can be more advantageously realized. Furthermore, since the inner circumferential end 26 of the swirl groove 16 is opened in the central groove 28, the slurry stored in the central groove 28 is transferred to the swirl groove 16 through the forceful opening. It becomes possible to supply stably. In addition, the slurry can be stably distributed over the entire vortex groove 16 in combination with the effect of discharging the slurry on the outer periphery of the slurry due to the rotation of the polishing pad 10. Since the swirl groove 16 is formed so as to spread in the circumferential direction of the polishing pad 10, a larger amount of slurry is used than the conventional structure in which the upward force of the polishing pad 10 is also dripping. At least, a necessary and sufficient amount of slurry can be efficiently supplied to the surface 14 of the polishing pad 10. Further, in the present embodiment, not only the slurry supply hole 30 connected to the central concave groove 28 but also a part of the slurry circulation hole 20 opened on the surface 14 of the polishing pad 10 is connected to the slurry supply communication groove 44. Therefore, the slurry can be supplied also from the powerful slurry circulation hole 20, and the slurry can be supplied more stably on the surface 14 of the polishing pad 10.

 [0100] Further, it is preferable that the used slurry used for polishing or the polishing debris generated by polishing is discharged from the surface 14 as quickly as possible. Since the vortex groove 16 is disposed over substantially the entire circumferential direction at each radial portion, it is possible to quickly catch used slurry and polishing debris. The used slurry and polishing debris in the vortex groove 16 are allowed to flow to the outer peripheral side of the polishing pad 10 due to the slurry discharging effect by the vortex groove 16, and then opened on the outer peripheral end surface of the polishing pad 10. It is possible to discharge from the outer peripheral side end 24 of the formed vortex groove 16. Further, in the present embodiment, the slurry discharge communication groove 52 provided in the platen 38 and the slurry circulation hole 20 formed in the polishing pad 10 are connected, so that used slurry and polishing debris can be more quickly collected. It is possible to discharge from the surface 14 of the polishing pad 10. As a result, unnecessary used slurry, polishing debris, etc. are quickly discharged from the surface 14 to keep the composition uniformity of the slurry supplied between the polishing pad 10 and the wafer 60 higher. Better polishing accuracy and polishing efficiency can be obtained.

[0101] Furthermore, in the polishing pad 10 according to the present invention, the spiral groove 16 and the central concave groove 28 opened on the pad surface 14 are gradually inclined radially outward from the bottom toward the opening. Therefore, when the polishing pad 10 is driven to rotate around the central axis 18, the centrifugal force acting on the slurry existing in the vortex groove 16 and the central groove 28 is vortexed. A component force in the direction of flowing out from the groove 16 and the center groove 28 is generated, and the hydraulic pressure of the slurry supplied from the bottom of the vortex groove 16 and the center groove 28 and the rotation speed of the polishing pad 10 are determined. It flows out from the opening to the outer peripheral side of the polishing pad 10 with a corresponding force, and is caused to flow so as to enter between the opposing surfaces of the polishing pad 10 and the wafer 60. In this way, in the vortex groove 16 and the central groove 28, the slurry is positively supplied from the bottom and spread in the circumferential direction, and then substantially uniformly over the entire circumference. And it flows out from the opening of the central groove 28 toward the outer peripheral side. Then, by simply adjusting the inclination angle of the swirl groove 16 and the central concave groove 28, the flow state of the slurry during polishing can be controlled. For example, the characteristics of the slurry to be used and the target By adjusting the inclination angles of the spiral groove 16 and the central concave groove 28 in consideration of various polishing conditions in addition to the characteristics of the wafer, it is possible to easily realize the optimum polishing state.

[0102] As a result, efficient inflow / outflow of slurry is performed in the vortex groove 16, and positive slurry flow is developed between the opposing surfaces of the polishing pad 10 and the wafer 60. As a result, the chemical polishing action of the slurry, which is not just the mechanical polishing action of the slurry, can be generated extremely efficiently and substantially uniformly throughout, and effective polishing can be realized stably. It is.

 In the above-described polishing method, the polishing pad 10 is rotated in the direction opposite to the direction of rotation of the vortex directed from the inner peripheral side end portion 26 of the vortex groove 16 to the outer peripheral side end portion 24. As a result, the slurry discharging effect of the vortex groove 16 is exerted, and the slurry supplied from the central groove 28 is moved from the inner peripheral side end 26 to the outer peripheral side end 24 of the vortex groove 16. Force that has been spread The polishing pad 10 is rotated from the inner peripheral side end 26 of the vortex groove 16 to the outer peripheral end 24 in the same direction as the direction of rotation of the vortex vortex 16 by the vortex groove 16. A polishing method that exhibits a slurry holding effect can also be effectively employed.

That is, by rotating the polishing pad 10 around the central axis 18 in the same direction as the direction of rotation of the vortex from the inner peripheral side end 26 to the outer peripheral side end 24 of the vortex groove 16, the vortex The slurry in the groove 16 can flow toward the inner peripheral side of the polishing pad 10. to this As a result, the used slurry and polishing debris captured by the vortex groove 16 can be collected in the central groove 28 while holding the slurry in the vortex groove 16. The used slurry and polishing debris collected in the central concave groove 28 in this way are connected to the slurry discharge communication groove 52 of the platen 38 by connecting a through hole formed with the same structure as the slurry supply hole 30. It can be discharged, or the suction tube body can be inserted into the central concave groove 28 from above and sucked to be discharged. Further, in such a polishing method, it is also possible to supply the slurry by dropping the slurry from the upper side of the polishing pad 10 as in a conventionally known polishing method.

 As is apparent from the above description, in the semiconductor substrate polishing method using the polishing pad 10 in the present invention, the slurry is selected by selecting the rotation direction of the polishing pad 10 provided with the swirl grooves 16. The discharge effect can be enhanced and the slurry retention effect can be enhanced, and when the rotation direction with the enhanced slurry discharge effect is selected, the slurry is stably stabilized from the central groove 28 to the entire spiral groove 16. However, if you select a rotation direction that enhances the slurry retention effect, you can collect used slurry and polishing debris in the central groove 28. The groove 28 can be used to advantage. As a result, the layer thickness of the slurry on the surface 14 can be adjusted to a high level, and used slurry and polishing debris can be quickly removed from the surface 14 to obtain excellent polishing accuracy and polishing efficiency.

 [0106] Next, various preferred embodiments of the present invention will be shown, but it should be understood that the description does not indicate that the aspects of the present invention are limited to the embodiments described below. . In each embodiment shown below, members and parts having the same structure as in the first embodiment described above are denoted by the same reference numerals as those in the first embodiment in the drawings. Detailed description thereof will be omitted.

[0107] First, FIG. 6 shows a polishing pad 70 as a second embodiment of the present invention. The polishing pad 70 is a so-called Bernoulli spiral in which vortex grooves 72 as vortex-like concave grooves are formed at different intervals on the radial line of the pad substrate 12. According to such a swirl groove 72, the flow of the slurry can be controlled with a higher degree of freedom in consideration of the centrifugal force acting on the slurry supplied to the polishing pad 70. In the present embodiment, the vortex groove 72 has a small radial interval at the inner peripheral portion of the polishing pad 70, and the outer periphery of the vortex groove 72 is reduced. It is possible to set the radial distance in the inner peripheral part to be larger, for example, to increase the radial distance in the inner peripheral part and gradually decrease the distance in the outer peripheral direction, or to the inner peripheral part. It is also possible to provide a plurality of parts with small intervals and parts with large intervals on the radial line from the outer periphery to the outer peripheral part. Further, the shape of the vortex groove 72 in the present embodiment does not need to be a spiral that is unified over its entire length, and various forms such as, for example, an Archimedean spiral having partially different coefficients in the radial direction are adopted. Can be adopted.

[0108] Next, FIG. 7 shows a polishing pad 76 as a third embodiment of the present invention. The polishing pad 76 has a central recess formed by a circular recess 78 as a circular counterbore-shaped central circular recess extending in a predetermined diameter. As shown in FIG. 8, the circular recess 78 is formed in the central portion of the polishing pad 76 as a recess having a circular outer peripheral wall surface 29 that opens to the surface 14 of the polishing pad 76 in a circular shape. Further, in the present embodiment, the opening edge 80 of the circular recess 78 is chamfered so as to open on the surface 14 with a smooth curved surface. The inner peripheral side end 26 of the vortex groove 16 is connected to the outer peripheral wall surface 29 of the powerful circular recess 78. In addition, a slurry supply hole 30 serving as a communication hole penetrating in the thickness direction is also opened at the bottom surface of the circular recess 78 as in the first embodiment described above.

[0109] According to such an aspect, the slurry can be supplied and discharged more effectively by the circular recess 78. That is, it is possible to secure a larger volume compared to the annular groove, and it is possible to store more slurry in the circular recess 78. Further, as in the present embodiment, the slurry supply hole 30 is connected to the circular recess 78 to supply the slurry from the bottom of the circular recess 78, or the slurry supply hole 30 is used to discharge the slurry. Therefore, it is possible to advantageously discharge the used slurry and polishing debris stored in the circular recess 78. In particular, when such a circular recess 78 is formed, it is possible to ensure a large opening dimension of the slurry supply hole 30 that opens to the bottom surface thereof, so that the supply and discharge of the slurry can be more effectively performed. Can be done. However, a communication hole such as the slurry supply hole 30 is not always necessary. When such a communication hole is not formed, the slurry is dropped into the circular recess 78 by a conventionally known slurry supply means. Supply When the slurry is discharged, for example, as described above, the suction tube body can be inserted into the circular recess 78 for suction. In particular, in the present embodiment, since the circular recess 78 is opened in the surface 14 in a circular shape, the suction tube can be easily inserted. Further, the slurry supply hole 30 may not necessarily be formed on the central axis of the circular recess 78, and may be formed at a position deviating from the central axis, or may be provided with a plurality of communication holes. Each may be used to supply and discharge slurry.

 [0110] Further, the specific shape of the bottom surface of the circular recess 78 is not limited in any way. For example, an upward spherical shape, a downward spherical shape, an upward conical shape, and a downward direction as shown in FIGS. 9 to 12, respectively. The conical shape and other various shapes can be used, but in order to prevent the slurry from staying on the bottom by hindering the fluidity of the slurry, there should be no step on the bottom of the circular recess 78. Is preferred.

 [0111] Further, when the circular recess 78 is formed, it can be formed by cutting, but it is preferably formed by forming a mold when the node substrate 12 is formed. It is not always necessary to chamfer the opening edge 80.

 Next, FIG. 13 shows a polishing pad 84 as a fourth embodiment of the present invention. The polishing pad 84 is formed by forming a plurality of vortex grooves 16 in the first embodiment described above. Here, each of the vortex grooves 16 is a vortex-like concave groove that is equally spaced on the radial line of the pad substrate 12, so that the vortex grooves 16 do not cross each other and are equally spaced on the radial line. It is formed to become. As the powerful swirl groove 16, it is also possible to form a plurality of spiral grooves having different intervals on the radial line as in the second embodiment described above.

The polishing pad 84 is formed with a central through hole 86 as a central recess that has a predetermined inner diameter and penetrates in the thickness direction of the pad substrate 12. As shown in FIG. 14, the central through hole 86 is formed as a through hole having a circular cross section having a substantially constant diameter and penetrating in the thickness direction of the pad substrate 12 in the same direction as the central axis 18. Further, the opening edge 88 is chamfered. Then, the inner peripheral side end 26 of the spiral groove 16 is connected to the cylindrical outer peripheral wall 29 in the central through-hole 86 so as to communicate therewith. It has been.

 [0114] In the polishing pad 84 having such a central through hole 86, the central through hole 86 as a central recess can be formed by punching or the like, and the structure according to the present invention can be more easily achieved. A polished polishing pad can be obtained. Further, as compared to the mode in which the communication hole is communicated with the central circular recess as described above, the central through hole 86 is penetrated through the pad substrate 12 with a constant diameter, so that more slurry can be generated. In addition to being able to store, slurry can be supplied and discharged more effectively. Furthermore, since the central through-hole 86, which serves as a tool escape in the spiral groove turning process, is penetrated in the thickness direction of the pad substrate 12, the depth dimension of the spiral groove is not limited. The depth dimension of the spiral groove can be set freely.

 [0115] It should be noted that the spacing between the radial grooves 16 in the radial direction does not necessarily have to be equal, and the flow characteristics of the slurry flowing on the surface 14 and the rotational speed of the polishing pad are taken into consideration. Thus, like the polishing pad 90 as the fifth embodiment shown in FIG. 15, it is also possible to form a plurality of vortex grooves 16 at different intervals on the radial straight line without crossing them. is there.

 Next, FIG. 16 shows a polishing pad 94 as a sixth embodiment of the present invention, and FIG. 17 shows a polishing pad 100 as a seventh embodiment of the present invention. The polishing pad 94 and the polishing pad 100 have substantially the same structure, and the spiral groove and the central recess have the same shape as the polishing pad 10 in the first embodiment described above. The surface 14 is formed with a vortex groove 16 having a vortex shape with equal radial spacing as a vortex-like groove, and has an annular groove shape as a central recess in the central portion thereof. A central concave groove 28 is formed, and the inner peripheral end 26 of the spiral groove 16 is connected to the central concave groove 28.

 [0117] Then, these polishing pads 94, 100 have curved intersecting grooves 96, as curved radial grooves extending radially from the central groove 28 toward the outer peripheral portion, intersecting with the swirl grooves 16, and A plurality of strips 102 are formed at substantially equal intervals in the circumferential direction.

[0118] The curved crossing concave grooves 96, 102 are formed with a depth dimension substantially equal to the spiral groove 16, and the inner peripheral side end is opened and connected to the central concave groove 28, and the outer periphery Side edge The force S is opened on the outer peripheral surface of the pad substrate 12. The curved cross groove 96 in the sixth embodiment is different from the curved cross groove 102 in the seventh embodiment in the bending direction, and the curved cross groove 96 has a diameter of the vortex groove 16 in diameter. The curved cross groove 102 is curved in the direction opposite to the rotational direction in which the vortex groove 16 extends radially outward, while being curved in the same direction as the rotational direction spreading outward in the direction. Note that the width, depth, number, etc. of the curved cross concave grooves 96 and 102 are appropriately set according to the material of the pad substrate 12, the material of the wafer to be processed, the required processing accuracy, etc. The For example, the number is preferably 220, more preferably 16. Further, like the swirl groove 16 in the first embodiment described above, a part or all of the wall surfaces of these curved intersecting grooves 96 and 102 may be formed as inclined surfaces, or an opening may be formed on the bottom surface. For example, a through hole may be formed.

[0119] The polishing pads 94 and 100 having such curved cross-concave grooves 96 and 102 are a combination of the rotational direction and the vortex shape of the vortex groove 16 and the curved shape of the curved cross-concave grooves 96 and 102. In addition to the slurry discharging effect or holding effect by the swirl groove 16, the slurry discharging effect or slurry holding effect by the curved cross concave grooves 96, 102 is combined in a more positive manner. It is possible to supply and discharge and to exert the effect of slurry circulation.

 That is, in the polishing pad 94 shown in FIG. 16, the curved cross-concave groove 96 is formed in the same direction as the rotational direction (counterclockwise in the figure) of the vortex groove 16 in which the vortex groove 16 spreads radially outward. Therefore, when the polishing pad 94 is rotated counterclockwise in the figure, the slurry in the vortex groove 16 is caused to flow inward of the polishing pad 94, and the slurry holding effect is exhibited. At the same time, the slurry in the curved intersecting groove 96 is also caused to flow inward of the polishing pad 94, and the holding effect of the slurry by the curved intersecting groove 96 is also exhibited. As a result, an inward force and flow of the slurry in the polishing pad 94 can be generated more effectively, and used slurry and polishing debris can be collected more effectively in the central groove 28.

[0121] On the other hand, when the clockwise polishing direction in the figure is adopted in the polishing pad 94, the slurry discharging effect of each of the swirl groove 16 and the curved crossing concave groove 96 can be exhibited. It becomes possible to discharge the slurry more effectively. [0122] On the other hand, in the polishing pad 100 shown in FIG. 17, the curved cross groove 102 is formed in the direction opposite to the direction of rotation of the spiral (counterclockwise in the figure) where the spiral groove 16 spreads radially outward. Therefore, by rotating the polishing pad 100 counterclockwise in the figure, the slurry retaining effect of the vortex groove 16 is exerted, and the slurry in the vortex groove 16 is inward of the polishing pad 100. While being allowed to flow, the curved crossing groove 102 exhibits a slurry discharging effect, and the slurry in the curved crossing groove 102 is discharged from the polishing pad 100. As a result, the slurry is discharged by the curved cross groove 102 while the slurry is caused to flow toward the central groove 28 by the vortex groove 16, and the circulation of the slurry can be effectively generated.

 [0123] On the contrary, when the clockwise rotation direction in the figure is adopted in the polishing pad 100 with force and force, the spiral groove 16 exerts the slurry discharging effect, while the curved cross groove 102 As a result, the slurry retention effect is exhibited. As a result, the slurry in the vortex groove 16 is caused to flow in the direction in which it is discharged from the polishing pad 100, while the slurry in the curved cross groove 102 is caused to flow toward the central groove 28 of the polishing pad 102. As a result, the circulation of the slurry is generated.

 [0124] Although not shown, the direction of rotation of the spiral in the spiral groove 16 is opposite to the direction of the spiral as shown (counterclockwise in the figure) (that is, clockwise in the figure). It is also possible to form it.

 That is, in the polishing pad 94 shown in FIG. 16, when the vortex groove 16 is formed with a shape that spreads in the clockwise direction opposite to that in FIG. 16, the rotational direction of the vortex groove 16 and the curved intersecting groove 96 Since the bending directions are different from each other, a contradictory effect is exhibited between the vortex groove 16 and the curved intersecting groove 96 as in the polishing pad 100 shown in FIG. Specifically, when such a polishing pad is rotated counterclockwise, a slurry discharge effect is exerted on the swirl groove 16, while a slurry holding effect is exerted on the curved cross groove 96. As a result, the circulation effect of the slurry is demonstrated. On the other hand, when rotated clockwise, the slurry holding effect is exhibited in the swirl groove 16 and the slurry discharging effect is exhibited in the curved intersecting groove 96.

In addition, in the polishing pad 100 shown in FIG. 17, when the swirl groove 16 is formed with a shape spreading in the clockwise direction opposite to that in FIG. 17, the rotational direction of the swirl groove 16 and the curved cross groove 102 Therefore, the same effect is exerted between the vortex groove 16 and the curved cross groove 102 as in the polishing pad 94 shown in FIG. Specifically, when the powerful polishing pad is rotated counterclockwise, the slurry discharging effect is exerted on both the swirl groove 16 and the curved cross groove 102, and the slurry is more actively generated. Exhausted. On the contrary, when rotated clockwise, the slurry holding effect is exerted on both the swirl groove 16 and the curved intersection groove 102, and more slurry can be collected in the central groove 28. .

 [0127] As described above, depending on the combination of the rotational direction of the polishing pad, the rotational direction of the spiral groove and the curved direction of the curved radial groove, the slurry can be retained or discharged more effectively. In order to improve the polishing rate while maintaining the slurry, the swirl-shaped concave grooves and the curved radial grooves can be combined together to exert the slurry holding effect. I hope that.

 [0128] The curved direction groove turning process for forming such a curved radial groove can be formed by the same process as the spiral groove turning process described above, and the spiral groove turning process is performed. A curved radial groove can be formed by performing cutting while rotating the pad substrate at a speed slower than that of the pad substrate. Also in this step, the central concave groove 28 is advantageously used as a base point of the cutting process or a tool escape, so that a curved radial groove having a constant depth dimension can be easily formed over the entire length. It is. In the curved radial groove turning process, the cutting tool may be fed in the radial direction by either the outer peripheral side or the inner peripheral side of the pad substrate.

Further, FIG. 18 shows a polishing pad 106 as an eighth embodiment of the present invention. The polishing pad 106 is a straight line as a linear radial groove in which the curved intersecting concave grooves 96 and 102 of the polishing pads 94 and 100 in the sixth and seventh embodiments described above extend linearly in the radial direction of the pad substrate 12. This is the cross groove 108. The straight crossing concave groove 108 is connected with its inner peripheral end opened to the central concave groove 28, and extends linearly outward from the inner peripheral end in the radial direction. The end is opened in the outer peripheral surface of the pad substrate 12. The straight crossing groove 108 is different from the curved crossing grooves 96 and 102 only in that it extends linearly outward in the radial direction. And the like can be appropriately changed in the same manner as in the curved crossing concave grooves 96 and 102. Such straight crossing grooves 108 extend in substantially the same direction as the direction in which the centrifugal force action is exerted by the rotation of the polishing pad 106, so that the slurry can be effectively discharged.

 [0130] In addition, as the linear radial groove cutting process for forming a forceful linear radial groove, in the above-described vortex-shaped concave groove turning process, the cutting blade is radially fixed with the pad substrate fixed in a non-rotatable state. It is possible to form a linear radial groove. Of course, the radial feeding can be performed from either the outer peripheral side or the inner peripheral side of the pad substrate. In this process as well, the central concave groove is advantageously used, and a constant depth dimension is provided over the entire length. It is possible to easily form the linear radial groove.

 [0131] While various embodiments have been exemplified, the widened portion 110 as a liquid reservoir as shown in Fig. 19 may be formed in the spiral groove in each of these embodiments. The widened portion 110 is formed by extending the inside of the depth dimension over the entire circumference of the swirl groove 16 rather than the opening width dimension of the swirl groove 16. In the vortex groove 16 provided with such a widened portion 110, more slurry can flow in the groove.

 [0132] In order to form such a widened portion 110, a liquid reservoir forming step as described below is preferably employed. That is, as shown in FIG. 20 (a), the vortex groove 16 having a constant groove width is formed by abutting the cutting edge 112 against the pad substrate 12 that has been rotationally operated in accordance with the above-described vortex-like groove turning process. Cutting form. Next, as shown in FIG. 20 (b), the cutting blade 1 14 having a predetermined inclination angle is inserted into the vortex groove 16, and the vortex groove 16 is rotated while the node substrate 12 is rotated. Cutting is done to trace. Then, the cutting blade 114 is fed in the radial direction while being fed little by little (preferably 0.05 mm). Then, as shown in FIG. 20 (c), the inner wall in the depth direction of the vortex groove 16 is widened by cutting the opposite wall surface in the same manner as in FIG. 20 (b). The widened portion 110 can be formed.

[0133] Note that the method of forming the widened portion 110 is not limited to the above-described embodiment. For example, as shown in FIG. 21 (a), a cutting blade 118 having the same shape as the desired widened portion 110 is swirled in advance with respect to a spiral groove 16 having a constant groove width formed by a spiral groove turning process. While rotating the pad substrate 12 with the bottom of the groove 1 6 inserted, the wall surface is cut as the vortex groove 16 is traced. Blade 118 diameter As shown in Fig. 21 (b), the same turning is performed on the other wall surface with the cutting blade 120 as shown in Fig. 21 (b). It is also possible to form the widened portion 110 to be formed.

 [0134] As described above, the force S described in detail for some embodiments of the present invention, these are merely examples, and the present invention is not limited in any way by the specific description of the force and the embodiments. It is not interpreted. In addition, the present invention can be implemented in an aspect to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art, and such an embodiment does not depart from the spirit of the present invention. Needless to say, both are included in the scope of the present invention.

 For example, like the polishing pad 130 shown in FIG. 22, a plurality of concentric central annular grooves 28, 132, 134, and 136 form a central recess, and each central circle. It is possible to form a total of four vortex grooves 16 extending from the annular grooves 28, 132, 134, 136. In this polishing pad 130, instead of the cutting edge 32 shown in the above-described central recess turning process, a plurality of cutting edges 142 as shown in FIG. 23 are arranged in parallel in the cutting direction at a predetermined interval. By using the tool 140, it is possible to manufacture with good working efficiency. That is, in the polishing pad 130 having such a structure, a plurality of central annular grooves 28, 132, 134, 136 are formed, so that the plurality of central annular grooves 28, 132, 134 are formed. , 136 are used as the cutter of the plurality of cutting blades 142, and the cutting tool 140 having the plurality of cutting blades 142 is used in the central recess turning process and the spiral groove turning process as described above. It becomes possible. As a result, a plurality of swirl grooves 16 can be formed simultaneously.

 [0136] Further, by using a cutting tool 140 having cutting blades 142 arranged with an inclination angle: string as shown in the figure, multiple central annular grooves and spiral grooves having a predetermined inclination angle are formed. It can be formed with good working efficiency.

 [0137] It should be noted that the radial spacing of the vortex grooves 16 in the polishing pad 130 described above is an equal interval. By using cutting tools arranged with different intervals between the cutting edges 142, multiple vortexes are provided. It is also possible to form the grooves 16 with different radial intervals.

[0138] Further, by using such a cutting tool having a plurality of cutting edges in the liquid reservoir forming step, Therefore, it is possible to simultaneously form the widened portion 110 with respect to the plurality of spiral grooves 16.

[0139] Various forms can be employed for the number and specific shapes of the slurry supply holes 30 as communication holes communicated with the central concave groove 28. For example, a slurry supply hole 124 shown in FIGS. 24 and 25 can be formed with a uniform distribution density in the circumferential direction of the central groove 28 and an opening shape substantially equal to the width dimension of the central groove 28. . According to such an embodiment, the slurry can be stably supplied to the central groove 28.

Further, as is clear from FIG. 25, the central groove 28 does not necessarily have to have an inclined surface. Further, the swirl groove 16, the curved cross groove 96, 102, and the straight cross groove 108 may be formed without having an inclined surface.

[0141] Further, the specific shape of the widened portion 110 is not limited in any way, and can be formed with various shapes as illustrated in FIGS. 26 to 34. It is possible to adopt other shapes as appropriate. Note that the components shown in FIGS. 26 to 34 are denoted by the same reference numerals as those of the widened portion 110 described above, and detailed description thereof is omitted.

 [0142] As a method of forming the spiral groove, in addition to the method exemplified in the present invention, for example, the spiral groove is formed by using one or a plurality of cutting blades without providing a central recess. When cutting, when the cutting edge that started cutting from the outer peripheral edge of the polishing pad reaches the inner peripheral edge of the spiral groove, it may be formed by pulling the cutting upward. Conceivable.

 Further, for the purpose of controlling the flow of slurry into and out of the swirl groove 16, chamfering may be performed on the opening edge of the swirl groove 16.

 [0144] Further, the use form of the polishing pad having the structure according to the present invention is not limited in any way, including the slurry supply method, and the polishing pad according to the present invention is used in various modes. Needless to say, it is possible to perform polishing on various kinds of materials such as a semiconductor substrate, and 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 central recess is provided at the inner peripheral end of the spiral recess, so that the spiral recess by cutting is performed. Grooves can be easily formed, and vortices that were previously difficult to mass-produce This makes it possible to easily manufacture a polishing pad having a bowl-shaped groove.

Claims

The scope of the claims  [1] A polishing pad having a thin disk shape, the back surface of which is a mounting surface superimposed on the rotating plate of the polishing apparatus, and the front surface of which is a polishing surface that exerts a polishing action on the semiconductor substrate. There,  A central recess having a cylindrical outer peripheral wall surface is formed in the central portion of the polishing surface, and the polishing surface extends in a vortex shape from the outer peripheral wall surface of the central recess toward the pad outer peripheral side. A polishing pad, characterized in that vortex-shaped concave grooves opened at the outer peripheral edge of the pad are cut and formed with a substantially constant cross-sectional shape.  [2] The polishing according to claim 1, wherein the central recess is constituted by a central annular groove composed of an annular circumferential groove having a substantially constant width dimension and continuously extending in the circumferential direction. pad. [3] The polishing pad according to [1], wherein the central recess is constituted by a circular counterbore-shaped central circular recess that widens with a predetermined diameter. 4. The polishing pad according to claim 2 or 3, wherein a communication hole is formed through the bottom wall portion of the central recess in the pad thickness direction. 5. The polishing pad according to claim 1, wherein the central recess is constituted by a central circular hole penetrating in the pad thickness direction with a predetermined inner diameter dimension. [6] The polishing pad according to any one of [1] to [5], wherein the spiral concave grooves are equally spaced on the pad radial direction along substantially the entire length. [7] The polishing pad according to any one of [1] to [5], wherein the spiral groove has portions with different intervals on the pad radial direction line. [8] The polishing pad according to any one of [1] or [7], wherein a plurality of the spiral grooves are formed without directly intersecting each other. [9] The central recess is formed by a plurality of concentric formations of the central annular groove according to claim 2, and the vortex wall is formed from each central annular groove. 9. The polishing pad according to claim 8, wherein a plurality of vortex-shaped grooves are formed as a whole at least more than the number of the central annular grooves by extending and forming the groove-shaped grooves. [10] On the polishing surface of the polishing pad, a curved radial groove extending in a curved shape from the central portion to the outer peripheral portion is formed so as to cross the spiral groove. The radially inner end of the curved radial groove opens to the outer peripheral wall surface of the central recess, and the radially outer end of the curved radial groove opens to the outer peripheral end surface of the pad. The polishing pad according to any one of claims 1 to 9. [11] On the polishing surface of the polishing pad, linear radial grooves extending in a linear shape from the central portion to the outer peripheral portion and extending radially are formed so as to cross the spiral groove. The radially inner end of the linear radial groove opens to the outer peripheral wall surface of the central recess, and the radially outer end of the linear radial groove opens to the outer peripheral end surface of the pad. A polishing pad according to any one of claims 1 to 10. 12. The polishing pad according to any one of claims 1 to 11, wherein the outer peripheral wall surface in the central recess is an inclined surface inclined in the depth direction with respect to the pad central axis. 13. The polishing pad according to claim 1, wherein at least one of both side walls in the width direction of the spiral groove is an inclined surface inclined in the depth direction with respect to the center axis of the pad. .  [14] The polishing pad according to any one of [1] to [13], wherein a through-hole is formed through the bottom wall portion of the spiral groove in the pad thickness direction. [15] The liquid reservoir according to any one of [1] to [14], wherein in the vortex-like concave groove, a width dimension inward in the depth direction is expanded more than a width dimension of the opening. Polishing pad. [16] In producing the polishing pad according to any one of claims 1 to 15,  A step of preparing a pad substrate made of a synthetic resin material having a thin disk shape, and a back surface of the pad substrate being supported by being overlapped on a rigid rotating plate, and rotating around the central axis of the pad substrate, A central recess turning process for forming the central recess by performing a cutting process in a circumferential direction on a central portion of the surface of the pad substrate, and the central recess and the pad outer periphery while rotating the pad substrate. A spiral groove turning process for forming the spiral groove by sending a cutting tool between the edges in a substantially pad radial direction and performing a cutting process;  A method for producing a polishing pad comprising: [17] In manufacturing the polishing pad according to claim 9, the central recess is obtained by using a multi-blade tool provided with a plurality of blade portions in parallel with the cutting direction as the cutting blade. 17. The method for producing a polishing pad according to claim 16, wherein a plurality of the central annular grooves are simultaneously formed in the turning process, and a plurality of the spiral grooves are simultaneously formed in the spiral groove turning process. . [18] In manufacturing the polishing pad according to claim 10, a cutting blade is formed between the central recess formed by the central recess turning step and the pad outer peripheral edge while the pad substrate is rotated. 18. The method for producing a polishing pad according to claim 16, further comprising a curved radial groove turning step for forming the curved radial groove by performing cutting process by feeding a substantially radial direction of the pad.  [19] In manufacturing the polishing pad according to claim 11, the center recess formed by the center recess turning step in a state where the pad substrate is supported in a fixed position, and the pad outer peripheral edge. 19. The polishing pad according to claim 16, further comprising a linear radial groove cutting step of forming the linear radial groove by feeding a cutting blade in a substantially pad radial direction to perform cutting. Method.  [20] In manufacturing the polishing pad according to claim 14, a drilling step of forming the through-hole by performing a drilling process in a plate thickness direction with the pad substrate supported in a fixed position. 20. The method for producing a polishing pad according to claim 16, further comprising:  [21] In manufacturing the polishing pad according to claim 15, a cutting blade is inserted into the spiral groove having a constant groove width formed by the spiral groove turning step, and the pad substrate is 21. The polishing according to claim 16, further comprising a liquid reservoir forming step of forming the liquid reservoir by feeding the cutting blade in a radial direction of the pad substrate and performing a cutting process while rotating. A method for manufacturing a pad.  [22] A method for polishing a semiconductor substrate using the polishing pad according to any one of claims 1 to 15,  The polishing pad is supported from the mounting surface side and is rotated about the rotation center axis, and a polishing slurry is supplied to the spiral groove through the central recess, and the workpiece is processed on the polishing surface. A method of polishing a semiconductor substrate, characterized by exerting a polishing action on the semiconductor substrate. [23] A method for polishing a semiconductor substrate using the polishing pad according to any one of claims 1 to 15. There  The polishing pad is supported from the side of the mounting surface, and is rotated in the direction opposite to the direction of the spiral that is directed from the outer peripheral edge of the polishing pad toward the center portion of the spiral groove around the rotation center axis. The polishing slurry that is allowed to flow on the polishing surface is caused to flow to the central recess, and the polishing surface has a polishing action on the semiconductor substrate that is the object to be covered. A method for polishing a semiconductor substrate.