Dressing device

Abstract

To provide a dressing device configured so that flatness of a polishing pad can be improved and cut amounts of the polishing pad can be made uniform during dressing.SOLUTION: A dressing device 1 is provided with a dresser 3 that performs dressing of a polishing pad 11a mounted on an upper surface plate 11 in an annular shape that polishes a work-piece, while moving along a trajectory 2c in a circular arc shape crossing an outer peripheral edge 14 and an inner peripheral edge 15 of the upper surface plate 11. The dresser 3 has a dressing region 33 which contacts the polishing pad 11a. Contact lengths S1 and S2 along a circumferential direction α of a surface plate between the dressing region 33 and the polishing pad 11a gradually become smaller as going from outside toward inside in a radial direction β of the surface plate, when the dresser 3 is positioned at the outer peripheral edge 14 of the upper surface plate 11, and gradually become smaller as going from the inside toward the outside in the radial direction β of the surface plate, when the dresser 3 is positioned at the inner peripheral edge 15 of the upper surface plate 11.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a dressing device for dressing a polishing pad attached to a surface plate of a polishing machine for polishing a workpiece.

Background Art

[0002] Conventionally, a dressing device for dressing a polishing pad attached to an annular surface plate for polishing a workpiece such as a silicon wafer is known. In a conventional dressing device, for example, as shown in FIGS. 14(a) and (b), a dresser 100 disposed between upper and lower surface plates includes a rod-shaped first grindstone 101 having a dressing surface 101a facing the upper surface plate, and a rod-shaped second grindstone 102 having a dressing surface 102a facing the lower surface plate. In the conventional dresser 100, the first and second grindstones 101 and 102 are pressed toward the upper and lower surface plates by a coaxial cylinder 104 for pressing via an elastic member (such as a leaf spring) 103 (see, for example, Patent Document 1).

[0003] Also, in the example shown in FIGS. 14(a) and (b), the first grindstone 101 and the second grindstone 102 are set to the same length. However, there is also a dressing device in which the lengths of a rod-shaped first grindstone 201 and a second grindstone 202 are different, such as the dresser 200 of a modified example shown in FIGS. 15(a) and (b). Even in the conventional dresser 200 shown in FIGS. 15(a) and (b), the first grindstone 201 has a dressing surface 201a facing the upper surface plate, and the second grindstone 202 has a dressing surface 202a facing the lower surface plate. The dresser 200 presses the first grindstone 201 toward the upper surface plate by a first cylinder 204a for pressing via an elastic member (such as a leaf spring) 203, and presses the second grindstone 202 toward the lower surface plate by a second cylinder 204b for pressing.

[0004] Furthermore, conventional dressing devices are known in which the dressing surface has an inner region located on the inner edge side of the surface plate during dressing, an outer region located on the outer edge side of the surface plate during dressing, and an intermediate region located between the inner and outer regions (see, for example, Patent Document 2). Here, the inner region extends for a required length in the radial direction of the surface plate and is formed in a shape that follows the inner edge of the surface plate. The outer region extends for a required length in the radial direction of the surface plate and is formed in a shape that follows the outer edge of the surface plate. Furthermore, the intermediate region extends for a required length in the radial direction of the surface plate, and its length extending in the circumferential direction of the surface plate is set to be shorter than the lengths of the inner and outer regions extending in the circumferential direction of the surface plate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-124750 [Patent Document 2] Patent No. 6535529 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in the dressing apparatus described in Patent Document 1, for example, the amount of material removed from the polishing pad is less at the outer and inner circumference of the surface plate than at the middle of the surface plate in the radial direction, resulting in a difference in the amount of material removed from the polishing pad between the outer and inner circumference of the surface plate and the middle of the surface plate in the radial direction. Therefore, there is a problem in that it is difficult to uniformly flatten the entire surface of the polishing pad. Also, in the dressing apparatus described in Patent Document 2, for example, there is a tendency to remove too much material from the polishing pad near the outer and inner edges of the surface plate during dressing, and the amount of material removed from the polishing pad varies greatly between the outer and inner circumference of the surface plate.

[0007] This invention was made in view of the above-mentioned problems, and aims to provide a dressing device that can improve the flatness of the polishing pad during dressing and make the amount of material removed by the polishing pad uniform. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a dressing apparatus comprising a dresser that dresses a polishing pad attached to an annular platen for polishing a workpiece, while moving along an arc-shaped trajectory intersecting the outer and inner edges of the platen, wherein the dresser has a dressing area that contacts the polishing pad, When the direction perpendicular to the track is defined as the first direction, and the direction perpendicular to the first direction and along the tangential direction of the track is defined as the second direction, the dressing region has a third edge that is one edge in the second direction and faces the outer peripheral edge of the surface plate, and a fourth edge that is the other edge in the second direction and faces the inner peripheral edge of the surface plate. The contact length between the dressing area and the polishing pad along the circumferential direction of the surface plate is The aforementioned third edge but In plan view On the outer edge of the aforementioned surface plate contact When this is done, the length gradually shortens from the radially outer side of the surface plate towards the radially inner side of the surface plate. The fourth edge but In plan view On the inner periphery of the aforementioned surface plate contact In this case, the length gradually shortens from the radially inner side of the surface plate to the radially outer side of the surface plate. [Effects of the Invention]

[0009] The dressing apparatus of the present invention can improve the flatness of the polishing pad during dressing and make the amount of material removed by the polishing pad uniform. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram illustrating the dressing apparatus and double-sided polishing machine of Example 1. [Figure 2] This is a schematic plan view showing the dressing apparatus and double-sided polishing machine of Example 1. [Figure 3] This is a plan view showing the first dressing surface of the dresser of Example 1. [Figure 4] This is a plan view showing the second dressing surface of the dresser in Example 1. [Figure 5] This is an explanatory diagram showing the dresser of Example 1 positioned at the outer edge of the surface plate. [Figure 6]This is an explanatory diagram showing the dresser of Example 1 positioned at the inner periphery of the surface plate. [Figure 7] This is an explanatory diagram showing the shape of the dressing area. [Figure 8] (a) This figure shows the contact length (first contact length) between the dressing area and the polishing pad in the circumferential direction of the surface plate, at a radial position of the surface plate when the dressing area is located at the outer edge of the surface plate. (b) This is an explanatory diagram showing the first contact length. [Figure 9] This is an explanatory diagram showing the contact length (second contact length) between the dressing area and the polishing pad in the circumferential direction of the surface plate when the dressing area is located at the inner periphery of the surface plate. [Figure 10] (a) A diagram showing the amount of material removed from the polishing pad by the dressing device of Example 1. (b) An explanatory diagram showing the measurement position of the amount of material removed from the polishing pad. [Figure 11] (a) A plan view showing the dressing area of ​​the dresser of the first comparative example. (b) A diagram showing the first contact length of the dresser of the first comparative example. (c) A diagram showing the amount of material removed from the polishing pad by the dresser of the first comparative example. [Figure 12] (a) A plan view showing the dressing area of ​​the dresser of the second comparative example. (b) A diagram showing the first contact length of the dresser of the second comparative example. (c) A diagram showing the amount of material removed from the polishing pad by the dresser of the second comparative example. [Figure 13] (a) A plan view showing the dressing region of the first modified example. (b) A diagram showing the first contact length in the dressing region of the first modified example. (c) A diagram showing the amount of material removed from the polishing pad by the dressing region of the first modified example. [Figure 14] (a) A first perspective view showing the dresser of a conventional dressing device. (b) A second perspective view showing the dresser of a conventional dressing device. [Figure 15] (a) A first perspective view showing a modified dresser of a conventional dressing device. (b) A second perspective view showing a modified dresser of a conventional dressing device. [Modes for carrying out the invention]

[0011] Hereinafter, an embodiment for implementing the dressing device of the present invention will be described based on Example 1 shown in the drawings.

[0012] The dressing device 1 of Example 1 is a dressing device for a double-sided polishing machine 10 that polishes both the front and back surfaces of a thin plate-shaped workpiece. That is, the dressing device 1 of Example 1 simultaneously dresses a polishing pad 11a attached to a rotatable upper platen 11 and a polishing pad 12a attached to a rotatable lower platen 12. Note that dressing means grinding or roughening the surfaces of the polishing pads 11a and 12a to restore the slurry holding ability of the polishing pads 11a and 12a and maintain the polishing ability of the double-sided polishing machine 10. It is desirable that the surfaces of the polishing pads 11a and 12a be uniformly flattened by dressing or that the amount of shaving of the polishing pads 11a and 12a be made uniform.

[0013] During dressing, the dressing device 1 inserts a dresser 3 between the upper and lower platens 11 and 12. Then, the double-sided polishing machine 10 rotates the upper platen 11 in a first direction (for example, counterclockwise, hereinafter referred to as "upper platen rotation direction CCW") by a rotating shaft 13 with the dresser 3 sandwiched between the upper platen 11 and the lower platen 12, and rotates the lower platen 12 in a second direction opposite to the first direction (for example, clockwise, hereinafter referred to as "lower platen rotation direction CW"). Thereby, the polishing pads 11a and 12a and the dresser 3 are in sliding contact, and the polishing pads 11a and 12a are dressed. Further, the upper platen 11 and the lower platen 12 have an annular shape (doughnut disk shape) with a rotating shaft 13 attached to the center. During dressing, the dresser 3 moves between the outer peripheral edge 14 and the inner peripheral edge 15 of the upper and lower platens 11 and 12.

[0014] As shown in FIGS. 1 and 2, the dressing device 1 includes an arm member 2, a dresser 3 provided at the tip 2b of the arm member 2, a drive mechanism 4 that rotates the arm member 2, and a control unit (not shown) that controls the drive mechanism 4.

[0015] The arm member 2 is a pipe member that extends horizontally from the drive mechanism 4, with its base 2a held by the drive mechanism 4 located near the double-sided polishing machine 10. The arm member 2 is rotated by the drive mechanism 4, allowing its tip 2b to move back and forth between the upper and lower platens 11 and 12. At this time, as shown in Figure 2, the tip 2b of the arm member 2 traces an arc-shaped trajectory 2c that intersects the outer periphery 14 and inner periphery 15 of the upper and lower platens 11 and 12. As a result, the dresser 3 provided on the tip 2b of the arm member 2 is moved along the trajectory 2c during dressing until it is positioned at the outer periphery 14 and inner periphery 15 of the upper and lower platens 11 and 12. When not dressing, the arm member 2 is rotated to a position that retracts the dresser 3 from between the upper and lower platens 11 and 12.

[0016] The dresser 3 comprises a dressing member 3a and a cleaning water spraying mechanism 3b. The dressing member 3a has the function of dressing the polishing pads 11a and 12a. The dressing member 3a includes a first dressing surface 31 (see Figure 3) that faces the upper platen 11 during dressing, and a second dressing surface 32 (see Figure 4) that faces the lower platen 12 during dressing. The first dressing surface 31 has a dressing area 33 that contacts the upper platen 11 during dressing, and the second dressing surface 32 has a dressing area 33 that contacts the lower platen 12 during dressing.

[0017] The cleaning water injection mechanism 3b has the function of injecting high-pressure cleaning water during dressing. The cleaning water injection mechanism 3b comprises a pair of first injection ports 34 (see Figure 3), three second injection ports 35 (see Figure 4), and a cleaning water passage (not shown), etc. The first injection ports 34 are provided on the first dressing surface 31 and inject cleaning water during dressing. The second injection ports 35 are provided on the second dressing surface 32 and inject cleaning water during dressing. The cleaning water passage penetrates the dressing member 3a and communicates with the first injection ports 34 and the second injection ports 35. The cleaning water is supplied through the inside of the arm member 2 and injected from the first injection ports 34 and the second injection ports 35 through the cleaning water passage. Here, the first injection ports 34 are located upstream of the dressing region 33 in the upper platen rotation direction CCW. Furthermore, the second nozzle 35 is positioned upstream of the dressing area 33 in the lower platen rotation direction CW. In addition, the tips of the first and second nozzles 34 and 35 are all positioned so as not to come into contact with the polishing pads 11a and 12a during dressing.

[0018] The dressing area 33 has almost the same shape as the first dressing surface 31 and the second dressing surface 32, and as shown in Figures 3 and 4, it exhibits an almost concave polygonal shape in plan view, which is symmetrical with respect to the center line O as the axis of symmetry. A "concave polygon" is a polygon that has one or more concave angles (angles with an interior angle of 180° or more). The dressing area 33 of Example 1 exhibits an almost pentagonal shape (concave pentagonal shape) in plan view, having one concave angle 50 and four convex angles from the first corner portion 51 to the fourth corner portion 54.

[0019] Furthermore, abrasive grains are electroplated onto the dressing area 33, and the grit size is set to any desired grit, such as #50 to #325. Diamond or CBN abrasive grains can be used for the abrasive grains electroplated onto the dressing area 33. In addition, the multiple circular holes 3c provided on the first dressing surface 31 and the second dressing surface 32 shown in Figures 3 and 4 are arbitrarily formed screw holes.

[0020] Then, as shown in Figure 2, the dresser 3 is positioned such that the center line O set in the dressing area 33 is aligned with the first direction X which is perpendicular to the track 2c. In the following explanation, the direction that is tangential to the track 2c and perpendicular to the first direction X will be referred to as the second direction Y.

[0021] The dressing area 33 has a first edge 41 which is one edge in the first direction X, a second edge 42 which is the other edge in the first direction X, a third edge 43 which is one edge in the second direction Y, and a fourth edge 44 which is the other edge in the second direction Y. Here, the first corner portion 51 is formed by the first edge 41 and the third edge 43. The second corner portion 52 is formed by the first edge 41 and the fourth edge 44. The third corner portion 53 is formed by the second edge 42 and the third edge 43. The fourth corner portion 54 is formed by the second edge 42 and the fourth edge 44. When the dresser 3 is placed between the upper and lower plates 11 and 12, the third edge 43 of the dressing area 33 faces the outer peripheral edge 14, and the fourth edge 44 faces the inner peripheral edge 15.

[0022] Furthermore, the dressing region 33 has a concave angle 50 with an interior angle of 180° or more set at the first edge 41. In other words, the first edge 41 has an intermediate point P in the middle of the second direction Y, which is closer to the second edge 42 than both ends (first corner portion 51 and second corner portion 52), and the vertex of the concave angle 50 is set at the intermediate point P. For this reason, the first edge 41 extends in a straight line with a bend in the middle when viewed from above.

[0023] In addition, in Example 1, the third edge 43 and the fourth edge 44 extend in a straight line when viewed from above. Furthermore, the second edge 42 is rounded in a plan view. Also, in Example 1, the first corner portion 51 to the fourth corner portion 54 are all curved in a rounded shape when viewed from above.

[0024] Furthermore, in the dressing region 33, the third edge 43 and the fourth edge 44 are inclined such that, in a plan view, they gradually approach each other from the first edge 41 side towards the second edge 42 side. That is, the length along the second direction Y from the third edge 43 to the fourth edge 44 gradually decreases from the first edge 41 side towards the second edge 42 side.

[0025] Furthermore, as shown in Figure 5, when the dresser 3 is positioned on the outer periphery 14 of the upper and lower platens 11 and 12, the third end edge 43 facing the outer periphery 14 aligns with the tangential direction of the outer periphery 14 (hereinafter referred to as the "first tangential direction Lα"). Note that "the dresser 3 is positioned on the outer periphery 14 of the upper and lower platens 11 and 12" means that the dresser 3 has moved along the track 2c to the outermost periphery of the upper and lower platens 11 and 12. The "first tangential direction Lα" is the tangential direction of the outer periphery 14 at the intersection Pa, which is the position where the third end edge 43 touches the outer periphery 14 in a plan view. Note that while Figure 5 shows the positional relationship between the upper platen 11 and the dressing region 33 set on the first dressing surface 31, the positional relationship between the lower platen 12 and the dressing region 33 set on the second dressing surface 32 is the same as the positional relationship shown in Figure 5. In other words, when the dresser 3 is positioned on the outer peripheral edge 14 of the upper and lower platen 11 and 12, the dressing area 33 set on the second dressing surface 32 also has its third end edge 43 aligned with the first tangential direction Lα.

[0026] Furthermore, as shown in Figure 6, when the dresser 3 is positioned on the inner periphery 15 of the upper and lower mounting plates 11 and 12, the fourth end edge 44 facing the inner periphery 15 aligns with the tangential direction of the inner periphery 15 (hereinafter referred to as the "second tangential direction Lβ"). Note that "when the dresser 3 is positioned on the inner periphery 15 of the upper and lower mounting plates 11 and 12" means that the dresser 3 has moved along the track 2c to the innermost circumference of the upper and lower mounting plates 11 and 12. The "second tangential direction Lβ" is the tangential direction of the inner periphery 15 at the intersection point Pb, which is the position where the fourth end edge 44 touches the inner periphery 15 in a plan view. In Figure 6, the positional relationship between the upper platen 11 and the dressing area 33 set on the first dressing surface 31 is shown, but the positional relationship between the lower platen 12 and the dressing area 33 set on the second dressing surface 32 is the same as the positional relationship shown in Figure 6. In other words, when the dresser 3 is positioned on the inner peripheral edge 15 of the upper and lower platens 11 and 12, the fourth end edge 44 of the dressing area 33 set on the second dressing surface 32 is aligned with the second tangential direction Lβ.

[0027] The vertex (midpoint P) of the concave angle 50 is set at the intersection of the first straight line L1 and the second straight line L2, which are set on the dressing region 33, as shown in Figure 7. Here, the first straight line L1 is parallel to the second tangent direction Lβ (fourth edge 44) and passes through the third corner 53. The second straight line L2 is parallel to the first tangent direction Lα (third edge 43) and passes through the fourth corner 54.

[0028] In Example 1, as shown in Figure 7, the angle θ1 (interior angle of the first corner portion 51) formed by the first edge 41 and the third edge 43 (first tangential direction Lα), and the angle θ2 (interior angle of the second corner portion 52) formed by the first edge 41 and the fourth edge 44 (second tangential direction Lβ), are set to the same angle. Also, the angle θ3 formed by the third edge 43 (first tangential direction Lα) and the first straight line L1, and the angle θ4 formed by the fourth edge 44 (second tangential direction Lβ) and the second straight line L2 are set to the same angle. Note that in Figure 7, the dressing region 33 is schematically shown to clearly indicate angles θ1 to θ4, and the first corner portions 51 to the fourth corner portions 54 are not curved in an R shape. Furthermore, while Figure 7 shows the dressing area 33 set on the first dressing surface 31, the same applies to the dressing area 33 set on the second dressing surface 32.

[0029] In addition, in Embodiment 1, the angle θ5 formed by the third edge 43 and the fourth edge 44, that is, the first tangential direction Lα and the second tangential direction Lβ, is also set to the same angle as angles θ3 and θ4. The angle θ5 is set according to the length of the arm member 2 and the radius of the upper and lower base plates 11 and 12, and is set to an angle greater than zero°, up to about 100°.

[0030] In the dressing apparatus 1 of Embodiment 1, when the dresser 3 is positioned on the outer peripheral edge 14 of the upper and lower platens 11 and 12, as shown in Figure 8(a), the contact length between the dressing area 33 and the polishing pads 11a and 12a in the circumferential direction of the upper and lower platens 11 and 12 (hereinafter referred to as "platen circumferential direction α") (hereinafter referred to as "first contact length S1," see Figure 8(b)) gradually decreases as the radial direction of the upper and lower platens 11 and 12 (hereinafter referred to as "platen radial direction β") moves from the outside to the inside. In other words, the first contact length S1 gradually shortens as the radial position of the platen moves from the third end edge 43 facing the outer peripheral edge 14 to the fourth end edge 44 facing the inner peripheral edge 15.

[0031] Furthermore, in Figure 8(a), the area enclosed by the X-axis, Y-axis, and the line indicating the first contact length S1 (the shaded area) represents the contact area between the dressing area 33 and the polishing pad 11a. When the dresser 3 is positioned on the outer peripheral edge 14 of the upper and lower platens 11 and 12, the contact area between the dressing area 33 and the polishing pad 11a gradually decreases from the outermost edge of the upper and lower platens 11 and 12, as can be seen from Figure 8(a), and takes on an approximately triangular shape when the horizontal axis is the platen radial direction β.

[0032] The first contact length S1 shown in Figures 8(a) and (b) represents the contact length in the circumferential direction α between the dressing region 33 set on the first dressing surface 31 and the polishing pad 11a provided on the upper platen 11. Although not shown, the first contact length S1 in the dressing region 33 set on the second dressing surface 32 is the same as the first contact length S1 shown in Figures 8(a) and (b). Also, the hole 3c is not taken into consideration when calculating the first contact length S1 here.

[0033] Furthermore, in the dressing apparatus 1 of Example 1, when the dresser 3 is located on the inner peripheral edge 15 of the upper and lower platens 11 and 12, the contact length between the dressing area 33 and the polishing pad 11a (12a) in the circumferential direction α of the platen (hereinafter referred to as "second contact length S2", see Figure 9) decreases as you move from the inside to the outside in the radial direction β of the platen. In other words, the second contact length S2 gradually shortens as the radial position of the platen moves from the fourth end edge 44 facing the inner peripheral edge 15 to the third end edge 43 facing the outer peripheral edge 14.

[0034] Note that the second contact length S2 shown in Figure 9 represents the contact length in the circumferential direction α of the platen between the dressing region 33 set on the first dressing surface 31 and the polishing pad 11a provided on the upper platen 11. However, the second contact length S2 in the dressing region 33 set on the second dressing surface 32 is the same as the second contact length S2 shown in Figure 9. Also, the second contact length S2 does not take into account the hole 3c.

[0035] Thus, in the dressing apparatus 1 of Example 1, the contact length (first contact length S1, second contact length S2) between the dressing area 33 and the polishing pads 11a, 12a in the circumferential direction α of the surface plate gradually decreases from the surface plate edge (outer edge 14 or inner edge 15) towards the inside of the surface plate (midway β in the surface plate radial direction), whether the dresser 3 is positioned at the outer edge 14 of the upper and lower surface plates 11, 12 or at the inner edge 15 of the upper and lower surface plates 11, 12.

[0036] Furthermore, grooves 60 are formed in the dressing area 33, as shown in Figures 3 and 4. The grooves 60 are recesses formed in the dressing area 33 and open to the side of the dresser 3. The grooves 60 are set to a width and depth that allows fluids such as cleaning water supplied during dressing to flow. Abrasive grains are not electrodeposited on the inside of the grooves 60. The grooves 60 of Example 1 have a first groove 61 and a second groove 62.

[0037] The first groove 61 extends along the first direction X and is formed in a position that coincides with the center line O in Embodiment 1.

[0038] The second groove 62 extends from the center position (center line O) in the second direction Y of the dressing region 33 toward the third edge 43 and the fourth edge 44, in a direction that follows the downstream direction with respect to the rotation of the upper platen 11 or the lower platen 12. "Following the downstream direction with respect to the rotation of the upper platen 11" means the direction in which the fluid flowing into the groove 60 flows downstream in the upper platen rotation direction CCW. The second groove 62 formed on the first dressing surface 31 extends in a direction that follows the downstream direction with respect to the rotation of the upper platen 11 (see Figure 3). "Following the downstream direction with respect to the rotation of the lower platen 12" means the direction in which the fluid flowing into the groove 60 flows downstream in the lower platen rotation direction CW. The second groove 62 formed on the second dressing surface 32 extends in a direction that follows the downstream direction with respect to the rotation of the lower platen 12 (see Figure 4). In other words, as shown in Figures 3 and 4, the upper platen rotation direction CCW and the lower platen rotation direction CW are opposite directions, so the second groove 62 formed on the first dressing surface 31 and the second groove 62 formed on the second dressing surface 32 extend in different directions in a plan view.

[0039] The operation of the dressing device 1 in Example 1 will be explained below.

[0040] In the dressing device 1 of Embodiment 1, when dressing the polishing pads 11a and 12a of the double-sided polishing machine 10, each part is controlled by a control unit (not shown), and first the arm member 2 is rotated by the drive mechanism 4. Then the drive mechanism 4 places the dresser 3, which is provided at the tip 2b of the arm member 2, between the upper platen 11 and the lower platen 12.

[0041] Next, the double-sided polishing machine 10 sets the gap height between the upper platen 11 and the lower platen 12 to a predetermined height. As a result, the dresser 3 is sandwiched between the upper and lower platens 11 and 12, the dressing area 33 set on the first dressing surface 31 contacts the polishing pad 11a of the upper platen 11, and the dressing area 33 set on the second dressing surface 32 contacts the polishing pad 12a of the lower platen 12.

[0042] Then, with the dressing areas 33 in contact with the polishing pads 11a and 12a respectively, the double-sided polishing machine 10 rotates the upper platen 11 and the lower platen 12 in opposite directions around the rotation axis 13. At this time, the dressing device 1 drives the drive mechanism 4 to rotate the arm member 2. As a result, the dressing device 1 moves the dresser 3 along the track 2c from the outer peripheral edge 14 side to the inner peripheral edge 15 side, or from the inner peripheral edge 15 side to the outer peripheral edge 14 side, bringing the polishing pads 11a and 12a into sliding contact with the dressing areas 33 and dressing the polishing pads 11a and 12a.

[0043] In the dressing apparatus 1 of Example 1, the contact length (first contact length S1, second contact length S2) between the dressing area 33 and the polishing pads 11a and 12a along the circumferential direction α of the surface plate gradually decreases from the surface plate edge (outer edge 14 or inner edge 15) towards the inside of the surface plate (midway along the surface plate radial direction β), whether the dresser 3 is positioned at the outer edge 14 of the upper and lower surface plates 11 and 12 or at the inner edge 15 of the upper and lower surface plates 11 and 12 (see, for example, Figure 8(a)).

[0044] In other words, when the dresser 3 is positioned on the outer peripheral edge 14 of the upper and lower surface plates 11 and 12, the first contact length S1 gradually decreases as you move from the outside to the inside in the radial direction β of the surface plates. Also, when the dresser 3 is positioned on the inner peripheral edge 15 of the upper and lower surface plates 11 and 12, the second contact length S2 gradually decreases as you move from the inside to the outside in the radial direction β of the surface plates.

[0045] Furthermore, in the dressing apparatus 1 of Embodiment 1, the first edge 41, which is one edge of the dressing area 33 in the first direction X, has an intermediate point P set in the middle of the second direction Y, which is closer to the third edge 43 than both ends (first corner 51, second corner 52). In other words, in Embodiment 1, the dressing area 33 has a concave polygonal shape in plan view, and the first edge 41 has a concave angle 50 with an interior angle of 180° or more. Also, the third edge 43 facing the outer peripheral edge 14 of the upper and lower platens 11 and 12, and the fourth edge 44 facing the inner peripheral edge 15 of the upper and lower platens 11 and 12, are inclined in plan view so that they gradually approach each other from the first edge 41 to the second edge 42.

[0046] As a result, as shown in Figure 10(a), the difference between the amount of material removed by the polishing pad 11a at the outer circumference (near the outer edge 14) and inner circumference (near the inner edge 15) of the upper platen 11 and the amount of material removed by the polishing pad 11a at the radially intermediate part of the upper platen 11 can be reduced without causing the dresser 3 to overhang. Also, although not shown, the polishing pad 12a provided on the lower platen 12 can also be dressed using the dressing device 1 of Embodiment 1, thereby reducing the difference between the amount of material removed by the polishing pad 12a at the outer circumference (near the outer edge 14) and inner circumference (near the inner edge 15) of the lower platen 12 and the amount of material removed by the polishing pad 12a at the radially intermediate part of the lower platen 12, without causing the dresser 3 to overhang. As a result, the dressing device 1 of Embodiment 1 can improve the flatness of the polishing pads 11a and 12a.

[0047] In Example 1, the dressing apparatus 1 performs dressing using a dressing force determined by the grit size, but during dressing, a dressing force obtained by the density, material, arrangement, etc. of the abrasive grains may also be used.

[0048] Furthermore, "overhang" refers to dressing the upper and lower platens 11 and 12 with a portion of the dresser 3 extending beyond the outer periphery 14 and inner periphery 15 of the platens. When the dresser 3 is overhanged, it becomes possible to dress the polishing pads 11a and 12a to a desired state on the outer and inner periphery of the upper and lower platens 11 and 12. However, in this case, the position adjustment of the dresser 3 becomes complicated, and interference between the dresser 3 and structures such as internal gears and sun gears may occur, making control difficult. For this reason, it is preferable not to overhang the dresser 3.

[0049] Furthermore, the amount of material removed from the polishing pad 11a shown in Figure 10(a) is the value measured along the measurement line LS shown in Figure 10(b). In addition, the amount of material removed from the polishing pad 11a shown in Figure 10(a) is the value obtained when the movement of the dresser 3 along the track 2c is stopped for a predetermined time (for example, 10 seconds) when the dressing area 33 of the first dressing surface 31 is in contact with the outer peripheral edge 14 of the upper platen 11, and when the dressing area 33 of the first dressing surface 31 is in contact with the inner peripheral edge 15.

[0050] In contrast, for example, the dresser of the first comparative example shown in Figure 11(a) has a dressing area 33X that is rectangular in shape when viewed from above. In the dresser of the first comparative example, when the dresser is positioned on the outer peripheral edge 14 or inner peripheral edge 15 of the upper and lower platens 11 and 12, the rotation of the arm member 2 causes the dressing area 33X to contact the outer peripheral edge 14 or inner peripheral edge 15 at an oblique angle. In other words, when the dresser of the first comparative example is positioned on the outer peripheral edge 14 of the upper and lower platens 11 and 12, the third end edge 43 of the dressing area 33 cannot follow the first tangential direction Lα, and when it is positioned on the inner peripheral edge 15 of the upper and lower platens 11 and 12, the fourth end edge 44 of the dressing area 33 cannot follow the second tangential direction Lβ. Therefore, for example, when the dresser of the first comparative example is located on the outer peripheral edge 14 of the upper and lower surface plates 11 and 12, the first contact length S1 does not continue to decrease from the outside (third edge 43) in the radial direction β of the surface plate towards the inside (fourth edge 44) of the radial direction β of the surface plate, as shown in Figure 11(b).

[0051] Furthermore, the contact area between the dressing region 33X and the polishing pad 11a, shown by the shaded area in Figure 11(b), exhibits a trapezoidal shape when the horizontal axis is the radial direction β of the platen. As a result, as shown in Figure 11(c), compared to the dressing device 1 of Example 1, the amount of material removed by the polishing pad 11a is reduced in the outer and inner periphery of the upper platen 11. On the other hand, in the middle of the platen radial direction β of the upper platen 11, the amount of material removed by the polishing pad 11a is greater compared to Example 1. In addition, with respect to the lower platen 12, the amount of material removed by the polishing pad 12a is less in the outer and inner periphery of the platen and greater in the middle of the platen radial direction β compared to Example 1. Therefore, when dressing is performed using the dresser of the first comparative example, the difference between the amount of material removed from the polishing pads 11a and 12a on the outer and inner circumferences of the upper and lower platens 11 and 12 and the amount of material removed from the polishing pads 11a and 12a in the middle portion of the platen radial direction β of the upper and lower platens 11 and 12 is larger than in Example 1, and the flatness of the polishing pads 11a and 12a cannot be improved.

[0052] Furthermore, for example, the dresser of the second comparative example shown in Figure 12(a) has a dressing region 33Y that, in plan view, has a shape in which the vertices of two triangles are connected. In the dresser of the second comparative example, for example, when the dresser is positioned on the outer peripheral edge 14 of the upper and lower surface plates 11 and 12, the first contact length S1 does not gradually decrease from the outside (third edge 43) in the radial direction β of the surface plate towards the inside (fourth edge 44) of the radial direction β of the surface plate, as shown in Figure 12(b), but rather increases along the way and then decreases again.

[0053] Furthermore, the contact area between the dressing region 33Y and the polishing pad 11a, shown by the shaded area in Figure 12(b), takes the shape of two triangles placed side by side when the horizontal axis is the radial direction β of the polishing platen. As a result, as shown in Figure 12(c), the amount of material removed by the polishing pad 11a varies greatly at the outer and inner circumferences of the upper polishing platen 11, creating a so-called step D. Therefore, it is not possible to improve the flatness of the polishing pad 11a.

[0054] Furthermore, in the dressing apparatus 1 of Embodiment 1, when the dresser 3 is positioned on the outer peripheral edge 14 of the upper and lower platens 11 and 12, the third end edge 43 of the dressing region 33 is aligned with the first tangential direction Lα. When the dresser 3 is positioned on the inner peripheral edge 15 of the upper and lower platens 11 and 12, the fourth end edge 44 of the dressing region 33 is aligned with the second tangential direction Lβ. Moreover, the midpoint P set on the first end edge 41 of the dressing region 33, that is, the vertex of the concave angle 50, is set on the intersection of the first straight line L1 parallel to the second tangential direction Lβ and the second straight line L2 parallel to the first tangential direction Lα.

[0055] As a result, in the dressing apparatus 1 of Example 1, when the dresser 3 is positioned at the outer peripheral edge 14 of the upper and lower platens 11 and 12, the contact length (first contact length S1) between the dressing area 33 and the polishing pads 11a and 12a along the circumferential direction α of the platen can be gradually reduced from the edge (outer peripheral edge 14) side towards the inside of the platen (midway in the radial direction β of the platen) (see Figure 8(a)). When the dresser 3 is positioned at the inner peripheral edge 15 of the upper and lower platens 11 and 12, the contact length (second contact length S2) between the dressing area 33 and the polishing pads 11a and 12a along the circumferential direction α of the platen can be gradually reduced from the edge (inner peripheral edge 15) side towards the inside of the platen (midway in the radial direction β of the platen). As a result, as shown in Figure 10(a), the dressing device 1 of Example 1 can suppress variations in the amount of material removed by the polishing pad 11a in the outer and inner periphery and the middle portion of the upper platen 11, and can improve the flatness of the polishing pad 11a.

[0056] Furthermore, in the dressing device 1 of Example 1, the angle θ1 formed by the first edge 41 and the third edge 43 (first tangential direction Lα) and the angle θ2 formed by the first edge 41 and the fourth edge 44 (second tangential direction Lβ) are set to the same angle. Also, the angle θ3 formed by the third edge 43 (first tangential direction Lα) and the first straight line L1 and the angle θ4 formed by the fourth edge 44 (second tangential direction Lβ) and the second straight line L2 are set to the same angle.

[0057] Therefore, the dressing device 1 of Example 1 can make the dressing area 33 a concave polygonal shape that is symmetrical in a plan view with the center line O as the axis of symmetry. As a result, the dressing device 1 of Example 1 can reduce the contact length (first contact length S1, second contact length S2) between the dressing area 33 and the polishing pads 11a, 12a along the circumferential direction α of the surface plate in the same way from the surface plate edge (outer edge 14 or inner edge 15) side toward the inside of the surface plate (midway along the surface plate radial direction β), whether the dresser 3 is positioned at the outer edge 14 of the upper and lower surface plates 11, 12 or at the inner edge 15 of the upper and lower surface plates 11, 12.

[0058] Furthermore, for example, as in the dressing region 33A of the first modified example shown in Figure 13(a), when angles θ1 and θ2 are set to angles significantly smaller than angles θ3 and θ4, as shown in Figure 13(b), when the dresser 3 is located on the outer peripheral edge 14 of the upper and lower surface plates 11 and 12, the reduction rate of the first contact length S1 changes significantly at an intermediate position (intermediate position) moving from the outside to the inside (from the third edge 43 to the fourth edge 44) in the radial direction β of the surface plates. Also, although not shown, when the dresser 3 is located on the inner peripheral edge 15 of the upper and lower surface plates 11 and 12, the reduction rate of the second contact length S2 changes significantly at an intermediate position (intermediate position) moving from the inside to the outside (from the fourth edge 44 to the third edge 43) in the radial direction β of the surface plates. Furthermore, the contact area between the dressing region 33 and the polishing pad 11a, which is shown with diagonal lines in Figure 13(b), does not form a triangle when the horizontal axis represents the radial position of the polishing platen.

[0059] However, even in such cases, as shown in Figure 13(c), the variation in the amount of material removed by the polishing pad 11a can be suppressed and the flatness of the polishing pad 11a can be improved by controlling the outer and inner circumference of the upper platen 11 and the intermediate portion in the radial direction β of the platen.

[0060] However, it is desirable that the shortest distance B from the straight line LB connecting the third corner 53 and the fourth corner 54 to the midpoint P (the vertex of the concave angle 50) be at least 10% of the shortest distance A from the straight line LA connecting the first corner 51 and the second corner 52 to the midpoint P (the vertex of the concave angle 50). If distance B is shorter than 10% of distance A, the area of ​​the dressing region 33A will become smaller, reducing the dressing function of the dressing device 1 and making it impractical.

[0061] Furthermore, in the dressing apparatus 1 of Example 1, a groove 60 is formed in the dressing area 33 that is open to the side of the dresser 3 and allows the washing water (fluid) supplied during dressing to flow through it.

[0062] As a result, the dressing device 1 of Example 1 can quickly discharge grinding debris from the polishing pads 11a and 12a generated by dressing, as well as deposits and by-products attached to the polishing pads 11a and 12a, from between the dressing area 33 and the polishing pads 11a and 12a using the washing water flowing through the groove 60.

[0063] Furthermore, in Example 1, the groove 60 has a first groove 61 along the first direction X. This improves the discharge performance of the cleaning water flowing along the first direction X and enhances the discharge performance of grinding chips. As a result, clogging of the dresser 3 can be suppressed.

[0064] Furthermore, in Example 1, the groove 60 has a second groove 62 that extends from the central position in the second direction Y of the dressing region 33 toward the third edge 43 and the fourth edge 44, in a direction that follows the downstream direction with respect to the rotation of the upper platen 11, or in a direction that follows the downstream direction with respect to the rotation of the lower platen 12. This improves the performance of discharging grinding chips and suppresses clogging of the dresser 3.

[0065] Furthermore, in the dressing apparatus 1 of Example 1, the second edge 42 of the dressing area 33 is rounded in plan view. This reduces resistance between the second edge 42 of the dressing area 33 and the polishing pad 11a. As a result, the first dressing surface 31 is prevented from catching on the polishing pad 11a, and damage to the polishing pad 11a and abrasive grains can be reduced.

[0066] The dressing apparatus of the present invention has been described above based on Example 1, but the specific configuration is not limited to this embodiment, and changes or additions to the design are permitted as long as they do not depart from the gist of the invention as described in each claim.

[0067] In Example 1, an example was shown in which the groove 60 has a first groove 61 and a second groove 62. However, the groove 60 may have either the first groove 61 or the second groove 62. Also, the groove 60 does not necessarily have to be formed in the dressing area 33. Furthermore, the size (width and depth) of the groove 60 can be set arbitrarily. In addition, the number of the first groove 61 and the second groove 62, and the positions in which they are formed, can also be set arbitrarily.

[0068] Furthermore, in Example 1, an example was shown in which the dressing device 1 includes a dresser 3 having a first dressing surface 31 and a second dressing surface 32, and can simultaneously dress the upper platen 11 and lower platen 12 of the double-sided polishing machine 10. However, the dresser 3 is not limited to this. For example, the dresser 3 may have only the first dressing surface 31 facing the polishing pad 11a of the upper platen 11, or the dresser 3 may have only the second dressing surface 32 facing the polishing pad 12a of the lower platen 12. In this case, the shapes of the first and second dressing surfaces 31 and 32 can be made into optimal shapes according to the rotation direction of the upper platen CCW and the rotation direction of the lower platen CW.

[0069] Furthermore, in the dressing apparatus 1 of Example 1, an example was shown in which the dressing area 33 exhibits a concave polygonal shape (concave pentagonal shape) in plan view, with a concave angle 50 set at the first edge 41. However, the dressing area 33 does not have to exhibit a concave polygonal shape in plan view. That is, the shape of the first edge 41 is not limited to the shape of Example 1, and for example, it may be set to draw an arc line with the midpoint P as the vertex in plan view. Also, the first edge 41 may be set to draw a stepped broken line connecting the first corner portion 51 and the midpoint P, and a stepped broken line connecting the second corner portion 52 and the midpoint P in plan view.

[0070] Furthermore, the dressing device 1 of Example 1 demonstrated an example of improving the flatness of the polishing pads 11a and 12a. However, the dressing device of the present invention can control how the first contact length S1 is reduced when the dresser 3 is positioned on the outer peripheral edge 14 of the upper and lower platens 11 and 12, and how the second contact length S2 is reduced when the dresser 3 is positioned on the inner peripheral edge 15 of the upper and lower platens 11 and 12, by controlling the position of the intermediate point P set on the first edge 41. In other words, it is possible to intentionally control the outer and inner peripheral portions of the polishing pads 11a and 12a to have shapes such as a "tight" (a state in which the outer and inner peripheral portions are not removed) or a "sloppy" (a state in which the outer and inner peripheral portions are removed).

[0071] Furthermore, the dressing apparatus of the present invention analyzes the shapes of the outer and inner circumferences of the polishing pads 11a and 12a after dressing has been performed. Based on the shape analysis of the polishing pads 11a and 12a after dressing, it is possible to appropriately set the shape of the contact area between the dressing area 33 and the polishing pads 11a and 12a (the shape of the area enclosed by the X-axis, Y-axis, and lines indicating the first contact length S1 and the second contact length S2), and to design the shape of the dressing area 33 (the position of the midpoint P) based on the set contact area shape. This allows for precise control of the shape of the polishing pads 11a and 12a.

[0072] Furthermore, although the dressing apparatus 1 of Example 1 was shown to have a washing water spraying mechanism 3b in the dresser 3, the washing water does not necessarily have to be able to be sprayed from the dresser 3. In other words, the dresser 3 does not have to have a washing water spraying mechanism 3b.

[0073] Furthermore, a double-sided polishing machine 10 equipped with a dressing device 1 may have a mechanism for fixing the upper platen 11 during dressing. In that case, the upper platen 11 may be fixed in a suspended state by a mechanism (hereinafter referred to as the "upper platen suspension fixing mechanism") at a position raised to a predetermined height, and dressing may be performed with the upper platen 11 fixed in place.

[0074] The upper platen suspension fixing mechanism is provided on the device frame that supports the upper platen 11 and the upper platen suspension provided on the upper platen 11 in a suspended state. The upper platen suspension fixing mechanism can control the vertical position (height) and vibration of the upper platen 11. The upper platen suspension fixing mechanism can have any structure and shape, such as a mechanism in which a locking member provided on a device frame such as a U-shaped, cylindrical, or claw-shaped device frame that can be driven to lock and release is locked to a locked member provided on the upper platen suspension to fix the device frame and the upper platen suspension, or conversely, a mechanism in which a locking member that can be driven to lock and release is provided on the upper platen suspension and a locked member is provided on the device frame. The driving direction when locking and releasing the locking member may be horizontal, or any other direction as long as it is possible to lock it to the locked part. Furthermore, the upper platen suspension fixing mechanism is not limited to the auto-dressing technology of the present invention, but can also be applied to dressing using other forms of platen dressers and pad dressers, as well as to maintenance work on any platen. [Explanation of Symbols]

[0075] 1 Dressing device 2 Arm members 2c orbit 3 Dresser 3a Dressing member 4. Drive mechanism 31. First dressing surface 32 Second dressing surface 33 Dressing Area 41 First edge 42 Second edge 43 Third edge 44. Fourth edge 50 concave angle 51 First corner 52 Second corner 53 Third corner 54. Fourth corner 60 groove 61 First groove 62 Second groove 10 Double-sided polishing machine 11 Upper surface plate 11a Polishing pad 12 Lower surface plate 12a Polishing pad 13 Rotation axis 14 Outer edge 15 Inner periphery X First direction (direction perpendicular to the orbit) Y Second direction (tangential direction of the orbit) Lα First tangent direction (tangent direction of the outer edge) Lβ Second tangent direction (tangent direction of the inner edge) The position where the third end edge touches the outer edge of Pa. The position where the fourth end edge touches the inner edge of Pb. L1 First straight line (a straight line parallel to the second tangent direction and passing through the third corner) L2 Second straight line (a straight line parallel to the first tangent direction and passing through the fourth corner) S1 First contact length (dressing area when the dresser is located on the outer edge of the surface plate) (Contact length between the polishing area and the polishing pad in the circumferential direction of the surface plate) S2 Second contact length (dressing area when the dresser is located on the inner edge of the surface plate) (Contact length between the polishing area and the polishing pad in the circumferential direction of the surface plate) α Surface plate circumferential direction β Surface plate radial direction

Claims

1. A dressing apparatus comprising a dresser that dresses a polishing pad attached to an annular platen for polishing a workpiece, while moving the pad along an arc-shaped trajectory that intersects the outer and inner edges of the platen, The dresser has a dressing area that contacts the polishing pad, When the direction perpendicular to the aforementioned track is defined as the first direction, and the direction perpendicular to the first direction and along the tangential direction of the aforementioned track is defined as the second direction, The dressing region has a third edge in one of the second directions that faces the outer peripheral edge of the surface plate, and a fourth edge in the other of the second directions that faces the inner peripheral edge of the surface plate. The contact length between the dressing area and the polishing pad along the circumferential direction of the surface plate is When the third end edge is in contact with the outer edge of the surface plate in a plan view, it gradually shortens from the radially outer side of the surface plate towards the radially inner side of the surface plate. When the fourth edge is in contact with the inner edge of the surface plate in a plan view, it gradually shortens from the radially inner side of the surface plate to the radially outer side of the surface plate. A dressing device characterized by the following features.

2. In the dressing apparatus described in claim 1, The dressing region has a first edge which is one edge in the first direction, a second edge which is the other edge in the first direction, a third edge, and a fourth edge. The first edge has an intermediate point in the middle of the second direction, which is set to be closer to the second edge than to both ends. The third and fourth edges, in a plan view, gradually approach each other as you move from the first edge towards the second edge. A dressing device characterized by the following features.

3. In the dressing apparatus described in claim 2, The dressing region is such that when the third edge is in contact with the outer edge of the surface plate in a plan view, the third edge is aligned in the tangential direction of the outer edge of the surface plate, and when the fourth edge is in contact with the inner edge of the surface plate in a plan view, the fourth edge is aligned in the tangential direction of the inner edge of the surface plate. The aforementioned midpoint is set on the intersection of a first straight line parallel to the tangential direction of the inner edge of the surface plate and a second straight line parallel to the tangential direction of the outer edge of the surface plate. A dressing device characterized by the following features.

4. In the dressing apparatus described in claim 3, The angle between the first edge and the third edge, and the angle between the first edge and the fourth edge are set to the same angle. The angle between the third edge and the first line and the angle between the fourth edge and the second line are set to be the same angle. A dressing device characterized by the following features.

5. In a dressing apparatus according to any one of claims 1 to 4, The dressing region is designed to allow fluid supplied during dressing to flow through it, and has grooves that are open to the sides of the dresser. A dressing device characterized by the following features.

6. In the dressing apparatus described in claim 5, The groove portion has a first groove portion that is aligned with the first direction. A dressing device characterized by the following features.

7. In the dressing apparatus described in claim 5, The dressing region has a first edge which is one edge in the first direction, a second edge which is the other edge in the first direction, a third edge, and a fourth edge. The groove portion has a second groove portion that extends from the central position in the second direction toward at least one of the third edge or the fourth edge, in a direction that follows the downstream direction with respect to the rotation of the surface plate. A dressing device characterized by the following features.

8. In a dressing apparatus according to any one of claims 1 to 4, The dressing region has a first edge which is one edge in the first direction, a second edge which is the other edge in the first direction, a third edge, and a fourth edge, and the second edge is rounded in plan view. A dressing device characterized by the following features.

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