JP2020131330A - Polishing device and polishing method - Google Patents

Abstract

To provide a polishing device which can prevent splash of a liquid including grinding sludge to a substrate to prevent contamination of the substrate, and to provide a polishing method.SOLUTION: A polishing device includes: a holding stage 4 which holds a substrate W; a stage rotation device M1 which rotates the holding stage 4; a polishing head 60 which presses a polishing tool 41 to the substrate W on the holding stage 4; a liquid supply nozzle 30 disposed above the holding stage 4; a porous member 110 disposed at the downstream side of the polishing head 60 in a rotation direction of the holding stage 4; and a liquid suction line 120 coupled to the porous member 110.SELECTED DRAWING: Figure 11

Description

The present invention relates to a polishing apparatus and a polishing method for polishing a substrate by pressing a polishing tool such as a polishing tape or a grindstone against the substrate while supplying a liquid to the substrate such as a wafer.

A polishing device that polishes the peripheral edge of a wafer, which is an example of a substrate, rotates the wafer and supplies a liquid to the upper surface of the wafer while pressing a polishing tool against the peripheral edge of the wafer to polish the peripheral edge. (See, for example, Patent Document 1). Abrasive grains are fixed on the surface of the polishing tool, and the polishing tool is slidably contacted with the peripheral edge portion of the wafer in the presence of a liquid to polish the peripheral edge portion.

When a wafer is being polished with a polishing tool, the materials constituting the surface of the wafer are gradually removed by the polishing tool to form polishing debris. The liquid supplied to the upper surface of the wafer forms a liquid film flowing toward the outside of the wafer to prevent polishing debris from adhering to the wafer. Abrasive debris mixes with the liquid and is discharged from the wafer together with the liquid.

JP-A-2009-154285

However, the liquid (including abrasive debris) once discharged from the wafer may collide with the surrounding structure and bounce off the upper surface of the wafer. Abrasive debris contained in the liquid adheres to the upper surface of the wafer and contaminates the wafer.

Therefore, the present invention provides a polishing apparatus and a polishing method capable of preventing a liquid containing polishing debris from bouncing back onto a substrate and preventing contamination of the substrate.

In one aspect, a holding stage that holds the substrate, a stage rotating device that rotates the holding stage, a polishing head that presses a polishing tool against the substrate on the holding stage, and a liquid supply arranged above the holding stage. Provided is a polishing apparatus including a nozzle, a porous member arranged on the downstream side of the polishing head in the rotation direction of the holding stage, and a liquid suction line connected to the porous member.

In one aspect, the porous member is a sponge.
In one aspect, at least a portion of the porous member is located higher than the holding stage.
In one aspect, the distance between the perforated member and the axis of the holding stage is shorter than the radius of the substrate.
In one aspect, the polishing device further comprises a porous member moving device that moves the porous member closer to the holding stage and away from the holding stage.

In one aspect, the perforated member is fixed to the polishing head.
In one aspect, the polishing apparatus further comprises a shroud cover arranged around the holding stage, which has a shape that surrounds the outer shape of the substrate.
In one aspect, the polishing device further comprises a liquid absorbing member fixed to the inner surface of the shroud cover.
In one aspect, the polishing apparatus further comprises a rinse liquid supply line connected to the porous member.

In one aspect, the substrate is held by a holding stage, a liquid is supplied to the upper surface of the substrate while rotating the substrate together with the holding stage, and a polishing tool is pressed against the substrate by a polishing head to polish the substrate. At the same time, there is provided a polishing method in which the liquid is brought into contact with a porous member arranged on the downstream side of the polishing head in the rotation direction of the holding stage, and the liquid is sucked from the porous member through a liquid suction line. To.

In one aspect, the porous member is a sponge.
In one aspect, at least a portion of the porous member is located higher than the holding stage.
In one aspect, the distance between the perforated member and the axis of the holding stage is shorter than the radius of the substrate.
In one aspect, the perforated member is non-contact with the substrate.
In one aspect, the perforated member is in contact with the substrate.
In one aspect, the polishing method further includes a step of supplying a rinsing liquid into the porous member to clean the porous member after polishing the substrate.

According to the present invention, the combination of the porous member and the liquid suction line can continuously remove the liquid containing the polishing debris from the substrate. As a result, it is possible to prevent the liquid from colliding with the structure in the polishing chamber and bouncing off the upper surface of the substrate.

1 (a) and 1 (b) are enlarged cross-sectional views showing a peripheral edge of a substrate. It is sectional drawing which shows one Embodiment of a polishing apparatus. It is a top view of the embodiment of the polishing apparatus shown in FIG. 2 is an enlarged view of the polishing head shown in FIGS. 2 and 3. It is a front view of the pressing member shown in FIG. It is a side view of the pressing member shown in FIG. FIG. 5 is a cross-sectional view taken along the line AA of FIG. It is a figure which shows the polishing head when the bevel part of a wafer is polished. It is a figure which shows the polishing head when the top edge portion of a wafer is polished. It is a figure which shows the polishing head when the bottom edge portion of a wafer is polished. It is an enlarged view which saw one Embodiment of a polishing head and a sponge from above. FIG. 11 is an enlarged view of the polishing head and sponge shown in FIG. 11 as viewed from the side. It is an enlarged view which looked at the other embodiment of a polishing head and a sponge from the top. FIG. 3 is an enlarged view of the polishing head and sponge shown in FIG. 13 as viewed from the side. It is an enlarged view which looked at the other embodiment of a polishing head and a sponge from the top. FIG. 15 is an enlarged view of the polishing head and sponge shown in FIG. 15 as viewed from the side. It is an enlarged view which looked at the other embodiment of a polishing head and a sponge from the top. It is sectional drawing of the shroud cover and the liquid absorption member shown in FIG. It is a top view which shows one Embodiment of the polishing apparatus provided with a plurality of polishing heads.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present specification, the peripheral edge portion of the substrate is defined as a region including a bevel portion located at the outermost periphery of the substrate and a top edge portion and a bottom edge portion located inside the bevel portion in the radial direction. An example of a substrate is a wafer.

1 (a) and 1 (b) are enlarged cross-sectional views showing a peripheral edge of a substrate. More specifically, FIG. 1A is a cross-sectional view of a so-called straight type substrate, and FIG. 1B is a cross-sectional view of a so-called round type substrate. In the substrate W of FIG. 1A, the bevel portion is a substrate W composed of an upper inclined portion (upper bevel portion) P, a lower inclined portion (lower bevel portion) Q, and a side portion (apex) R. It is the outermost peripheral surface (indicated by reference numeral B). In the substrate W of FIG. 1B, the bevel portion is a portion (indicated by reference numeral B) having a curved cross section, which constitutes the outermost peripheral surface of the substrate W. The top edge portion is a flat annular portion E1 located inside the bevel portion B in the radial direction. The bottom edge portion is a flat annular portion E2 located on the opposite side of the top edge portion E1 and located inside the bevel portion B in the radial direction. The top edge portion E1 may include a region in which the device is formed. The top edge portion E1 and the bottom edge portion E2 are connected to the bevel portion B.

FIG. 2 is a cross-sectional view showing an embodiment of the polishing apparatus, and FIG. 3 is a plan view of the embodiment of the polishing apparatus shown in FIG. The polishing apparatus includes a substrate holding portion 3 that holds and rotates a wafer W, which is an example of a substrate. 2 and 3 show a state in which the substrate holding portion 3 holds the wafer W. The substrate holding portion 3 includes a holding stage 4 having a holding surface 4a for holding the lower surface of the wafer W by vacuum suction, a hollow shaft 5 connected to the central portion of the holding stage 4, and a motor connected to the hollow shaft 5. It is equipped with M1. The motor M1 is connected to the holding stage 4 via a hollow shaft 5. In the present embodiment, the motor M1 constitutes a stage rotating device that rotates the holding stage 4. The arrow A shown in FIG. 3 indicates the rotation direction of the holding stage 4.

The wafer W is placed on the holding surface 4a of the holding stage 4 so that the center of the wafer W coincides with the axis of the hollow shaft 5. The holding stage 4 is arranged in the polishing chamber 22 formed by the partition wall 20. Above the holding stage 4, a liquid supply nozzle 30 that supplies liquid to the surface of the wafer W on the holding surface 4a is arranged. As the liquid, a liquid containing no abrasive grains (for example, pure water) is used.

The hollow shaft 5 is supported by a ball spline bearing (linear motion bearing) 6 so as to be vertically movable. A groove 4b is formed on the holding surface 4a of the holding stage 4, and the groove 4b communicates with a communication passage 7 extending through the hollow shaft 5. The communication passage 7 is connected to the vacuum line 9 via a rotary joint 8 attached to the lower end of the hollow shaft 5. The communication passage 7 is also connected to a nitrogen gas supply line 10 for separating the polished wafer W from the holding stage 4. By switching between these vacuum lines 9 and the nitrogen gas supply line 10, the wafer W is held on the holding surface 4a of the holding stage 4 and separated.

The hollow shaft 5 is rotated by the motor M1 via a pulley p1 connected to the hollow shaft 5, a pulley p2 attached to the rotating shaft of the motor M1, and a belt b1 hung on these pulleys p1 and p2. .. The ball spline bearing 6 is a bearing that allows the hollow shaft 5 to move freely in the longitudinal direction thereof. The ball spline bearing 6 is fixed to the cylindrical casing 12. Therefore, the hollow shaft 5 can move linearly up and down with respect to the casing 12, and the hollow shaft 5 and the casing 12 rotate integrally. The hollow shaft 5 is connected to an air cylinder (elevating device) 15, and the hollow shaft 5 and the holding stage 4 can be raised and lowered by the air cylinder 15.

A radial bearing 18 is interposed between the casing 12 and a cylindrical casing 14 arranged concentrically on the outer side of the casing 12, and the casing 12 is rotatably supported by the radial bearing 18. With such a configuration, the substrate holding portion 3 can rotate the holding stage 4 holding the wafer W about its axis O and raise and lower it along the axis O of the holding stage 4.

A polishing unit 40 for polishing the peripheral edge of the wafer W is arranged on the outer side of the holding stage 4 of the substrate holding portion 3 in the radial direction. The polishing unit 40 includes a polishing head assembly 44 that presses a polishing tape 41 against the peripheral edge of the wafer W to polish the peripheral edge, and a polishing tape supply mechanism 45 that supplies the polishing tape 41 to the polishing head assembly 44. Is equipped with. The polishing head assembly 44 is arranged inside the polishing chamber 22, and the polishing tape supply mechanism 45 is arranged outside the polishing chamber 22. The substrate holding unit 3 and the polishing unit 40 are electrically connected to the operation control unit 11, and the operations of the substrate holding unit 3 and the polishing unit 40 are controlled by the operation control unit 11. The operation control unit 11 is composed of at least one computer.

The polishing tape supply mechanism 45 includes a supply reel 48 that supplies the polishing tape 41 to the polishing head assembly 44, and a take-up reel 49 that winds up the polishing tape 41 used for polishing the wafer W. Motors 51 and 51 are connected to the supply reel 48 and the take-up reel 49, respectively (FIG. 3 shows only the motor 51 connected to the supply reel 48). Each of the motors 51 and 51 can apply a predetermined torque to the supply reel 48 and the take-up reel 49 to apply a predetermined tension to the polishing tape 41.

The polishing head assembly 44 includes a polishing head 60 for pressing the polishing surface of the polishing tape 41 against the peripheral edge of the wafer W. The polishing tape 41 is supplied to the polishing head 60 so that the polishing surface of the polishing tape 41 faces the peripheral edge of the wafer W. The polishing tape 41 is supplied from the supply reel 48 to the polishing head 60 through the opening 20b provided in the partition wall 20, and the used polishing tape 41 is wound on the take-up reel 49 through the opening 20b.

As shown in FIG. 3, the polishing head 60 is fixed to one end of the arm 63, and the arm 63 is configured to be rotatable around a rotation axis Ct parallel to the tangential direction of the wafer W. The other end of the arm 63 is connected to the motor 65 via pulleys p3 and p4 and a belt b2. When the motor 65 rotates clockwise and counterclockwise by a predetermined angle, the arm 63 and the polishing head 60 rotate about the axis Ct by a predetermined angle. In the present embodiment, the tilt mechanism that tilts the polishing head 60 with respect to the holding surface 4a (that is, the upper surface and the lower surface of the wafer W) of the holding stage 4 by the motor 65, the arm 63, the pulleys p3, p4, and the belt b2. It is configured.

As shown in FIG. 2, the tilt mechanism is mounted on the moving table 70. The moving table 70 is movably connected to the base plate 21 via a linear motion guide 71. The linear motion guide 71 extends linearly in the radial direction of the wafer W held by the substrate holding portion 3, and the moving table 70 is linearly movable in the radial direction of the wafer W. A connecting plate 73 penetrating the base plate 21 is attached to the moving table 70, and a linear actuator 75 is connected to the connecting plate 73 via a joint 76. The linear actuator 75 is directly or indirectly fixed to the base plate 21.

As the linear actuator 75, a combination of an air cylinder, a positioning motor, and a ball screw can be adopted. The linear actuator 75 and the linear motion guide 71 constitute a moving mechanism for linearly moving the polishing head 60 in the radial direction of the wafer W. That is, the moving mechanism operates so as to move the polishing head 60 closer to and further from the holding surface 4a (that is, the wafer W) of the holding stage 4 along the linear motion guide 71. The polishing tape supply mechanism 45 is fixed to the base plate 21.

The partition wall 20 is provided with a transport port 20a for loading and unloading the wafer W into and out of the polishing chamber 22. The transport port 20a is formed as a notch extending horizontally. The transport port 20a can be closed by the shutter 23.

FIG. 4 is an enlarged view of the polishing head 60 shown in FIGS. 2 and 3. As shown in FIG. 4, the polishing head 60 has a pressing member 80 for pressing the polished surface of the polishing tape 41 against the peripheral edge of the wafer W, and the pressing member 80 toward the holding surface 4a of the holding stage 4 (that is,). The air cylinder 90 is provided as a head actuator for moving the wafer W (toward the peripheral edge of the wafer W). The pressing member 80 and the air cylinder 90 are arranged on the back side of the polishing tape 41. By controlling the pressure of the gas supplied to the air cylinder 90, the polishing load on the wafer W is adjusted.

A tape feeding mechanism 100 for feeding the polishing tape 41 in the longitudinal direction is attached to the polishing head 60. In the present embodiment, the tape feeding mechanism 100 is fixed to the polishing head 60, but in one embodiment, the tape feeding mechanism 100 may be provided at a position away from the polishing head 60.

The tape feed mechanism 100 includes a tape feed roller 100a, a nip roller 100b, and a motor 100c for rotating the tape feed roller 100a. The motor 100c is provided on the side surface of the polishing head 60, and a tape feed roller 100a is attached to the rotating shaft of the motor 100c. The nip roller 100b is arranged adjacent to the tape feed roller 100a. The nip roller 100b is supported by a mechanism (not shown) so as to generate a force in the direction indicated by the arrow NF in FIG. 4 (direction toward the tape feed roller 100a), and is configured to press the tape feed roller 100a. ..

When the motor 100c rotates in the direction of the arrow shown in FIG. 4, the tape feed roller 100a rotates to feed the polishing tape 41 from the supply reel 48 to the take-up reel 49 via the polishing head 60. The nip roller 100b is configured to be able to rotate about its own axis. During polishing of the wafer W, the tape feeding mechanism 100 feeds the polishing tape 41 in the longitudinal direction thereof at a predetermined speed (for example, several mm to several tens of mm per minute).

The polishing head 60 has a plurality of guide rollers 103A, 103B, 103C, 103D, 103E, 103F, 103G. These guide rollers 103A to 103G guide the polishing tape 41 so that the polishing tape 41 advances in a direction orthogonal to the tangential direction of the wafer W.

5 is a front view of the pressing member 80 shown in FIG. 4, FIG. 6 is a side view of the pressing member 80 shown in FIG. 5, and FIG. 7 is a sectional view taken along line AA of FIG. As shown in FIGS. 5 to 7, the pressing member 80 is a first pressing member for pressing the polishing tape 41 against the top edge portion of the wafer W (see reference numeral E1 in FIGS. 1A and 1B). The 81, the second pressing member 82 for pressing the polishing tape 41 against the bevel portion of the wafer W (see reference numerals B in FIGS. 1A and 1B), and the polishing tape 41 against the bottom edge portion of the wafer W. It is composed of a third pressing member 83 for pressing against (see reference numeral E2 in FIGS. 1A and 1B).

The first pressing member 81, the second pressing member 82, and the third pressing member 83 are fixed to the base 105. The first pressing member 81 and the third pressing member 83 may be integrally formed with the base 105. The second pressing member 82 is arranged between the first pressing member 81 and the third pressing member 83.

The tips of the first pressing member 81 and the third pressing member 83 are composed of protruding blades 81A and 83A shaped like rails. These protrusion blades 81A and 83A are arranged in parallel with each other. The protrusion blades 81A and 83A are curved along the circumferential direction of the wafer W. More specifically, the protrusion blades 81A and 83A have an arc shape having substantially the same curvature as the curvature of the wafer W.

The two protruding blades 81A and 83A are arranged symmetrically with respect to the second pressing member 82. That is, as shown in FIG. 5, the protrusion blades 81A and 83A are curved inward toward the second pressing member 82 when viewed from the front. The polishing head 60 is installed so that the center of the second pressing member 82 coincides with the center of the wafer W in the thickness direction. The protrusion blades 81A and 83A are arranged closer to the wafer W than the guide rollers 103D and 103E (see FIG. 4) arranged on the front surface of the polishing head 60, and the back surface of the polishing tape 41 is arranged on the back surface of the polishing tape 41. Supported by. The protruding blades 81A and 83A are formed of a resin such as PEEK (polyetheretherketone).

The second pressing member 82 is arranged between the two protrusion blades 81A and 83A. The second pressing member 82 is made of an elastic material such as silicone rubber. The height of the second pressing member 82 is slightly lower than the height of the protrusion blades 81A and 83A. When the pressing members 81, 82, 83 are moved toward the wafer W by the air cylinder 90 while the polishing head 60 is maintained parallel to the holding surface 4a (see FIG. 2) of the holding stage 4, the second pressing member 82 Presses the polishing tape 41 against the bevel portion of the wafer W from the back side thereof.

The operation of the polishing apparatus configured as described above is as follows. With the shutter 23 shown in FIG. 2 open, the wafer W to be polished is carried into the polishing chamber 22 from the transport port 20a by a hand (not shown) of the transport mechanism. The air cylinder 15 operates to raise the holding stage 4, and the wafer W is held on the holding surface 4a of the holding stage 4. After that, the hand of the transport mechanism moves out of the polishing chamber 22, and the transport port 20a is closed by the shutter 23. The holding stage 4 descends to a predetermined polishing position together with the wafer W. FIG. 2 shows a state in which the wafer W is in the polishing position.

The holding stage 4 and the wafer W are rotated by a motor M1 as a stage rotating device. The liquid supply nozzle 30 supplies liquid (for example, pure water) to the center of the upper surface of the rotating wafer W, while the polishing head 60 presses the polished surface of the polishing tape 41 against the peripheral edge of the wafer W. The liquid spreads over the entire upper surface of the wafer W by centrifugal force, and forms a liquid film on the upper surface of the wafer W. The peripheral edge of the wafer W is polished by the polishing tape 41 in the presence of a liquid. During polishing of the wafer W, the polishing tape 41 is fed from the supply reel 48 to the take-up reel 49 via the polishing head 60 at a predetermined speed by the tape feeding mechanism 100.

When polishing the bevel portion of the wafer W, as shown in FIG. 8, the polishing surface of the polishing tape 41 is pressed by the second pressing member 82 while continuously changing the inclination angle of the polishing head 60 by the above-mentioned tilt mechanism. It is pressed against the bevel portion of the wafer W. When polishing the top edge portion of the wafer W, as shown in FIG. 9, the polishing head 60 is tilted upward, and the polished surface of the polishing tape 41 is pressed against the top edge portion of the wafer W by the protrusion blade 81A to press the top edge portion. Polish the part. When polishing the bottom edge portion of the wafer W, as shown in FIG. 10, the polishing head 60 is tilted downward, and the polished surface of the polishing tape 41 is pressed against the bottom edge portion of the wafer W by the protrusion blade 83A to press the bottom edge portion. Polish the part.

As described above, the polishing head 60 of the present embodiment can polish the entire peripheral edge portion of the wafer W including the top edge portion, the bevel portion, and the bottom edge portion. The order in which the top edge portion, the bevel portion, and the bottom edge portion are polished is not particularly limited. For example, the peripheral edge of the wafer W may be polished in the order of the top edge portion, the bevel portion, and the bottom edge portion, or the peripheral edge portion of the wafer W may be polished in the order of the bevel portion, the top edge portion, and the bottom edge portion. You may.

When the polishing of the wafer W is completed, the supply of the liquid is stopped, and the rotation of the holding stage 4 and the wafer W is stopped. The shutter 23 is opened, and the hand of the transport mechanism (not shown) enters the polishing chamber 22. Further, the holding stage 4 rises with the wafer W. The hand of the transfer mechanism grips the wafer W and carries out the wafer W from the polishing chamber 22 through the transfer port 20a.

As shown in FIG. 3, the polishing apparatus has a sponge 110 arranged on the downstream side of the polishing head 60 in the rotation direction of the holding stage 4 and the wafer W (indicated by an arrow A), and a liquid suction connected to the sponge 110. It has a line 120. The sponge 110 is an example of a porous member, and a porous member other than the sponge may be used as long as it has the same function as the sponge 110. For example, a block made of an elastic material such as rubber and having a large number of holes may be used as the porous member.

The sponge 110 is a liquid absorbing member made of an elastic porous material that can easily absorb the liquid inside. In this embodiment, the sponge 110 is made of synthetic resin. The liquid suction line 120 extends from the inside of the polishing chamber 22 to the outside of the polishing chamber 22. One end of the liquid suction line 120 is connected to the sponge 110, and the other end of the liquid suction line 120 is connected to the vacuum source 125 arranged outside the polishing chamber 22. The liquid suction line 120 extends to the vacuum source 125 via the gas-liquid separator 123. As the vacuum source 125, a vacuum line as a utility facility provided in a factory where a polishing device is installed can be used. Alternatively, a vacuum pump may be used as the vacuum source 125.

FIG. 11 is an enlarged view of one embodiment of the polishing head 60 and the sponge 110 as viewed from above, and FIG. 12 is an enlarged view of the polishing head 60 and the sponge 110 shown in FIG. 11 as viewed from the side. In FIGS. 11 and 12, the polishing head 60 is schematically depicted. The sponge 110 is arranged on the downstream side of the polishing head 60 and close to the side surface 60a of the polishing head 60. The entire sponge 110 is arranged at a position higher than the holding surface 4a of the holding stage 4. In the present embodiment, the entire sponge 110 is arranged at a position higher than the upper surface of the wafer W on the holding stage 4, and is separated from the upper surface of the wafer W.

The sponge 110 is located on the downstream side of the polishing head 60 in the rotation direction of the wafer W. The sponge 110 arranged at such a position can absorb the liquid containing the material of the wafer W (hereinafter referred to as polishing debris) removed by contact with the polishing tape 41 and capture the polishing debris. That is, the polishing debris is taken into the sponge 110 together with the liquid and sent out of the polishing chamber 22 through the liquid suction line 120.

According to the present embodiment, since the sponge 110 is close to the side surface 60a on the downstream side of the polishing head 60, the sponge 110 is a contaminated liquid before the liquid containing the polishing debris (hereinafter referred to as a contaminated liquid) is scattered from the wafer W. Can be absorbed. In particular, since the sponge 110 is entirely composed of a porous material capable of absorbing the liquid, the contaminated liquid can be captured in a wide area. Therefore, it is possible to reliably prevent the contaminated liquid from scattering from the wafer W. Further, the liquid suction line 120 can remove the contaminated liquid from the sponge 110 and restore the absorption capacity of the sponge 110. Therefore, the combination of the sponge 110 and the liquid suction line 120 can ensure continuous removal of contaminants over a large area.

The sponge 110 is close to, but not in contact with, the wafer W on the holding stage 4. This is to prevent the polishing debris once captured by the sponge 110 from adhering to the device formed on the upper surface of the wafer W. In one embodiment, a part of the sponge 110 may come into contact with the bevel portion of the wafer W on which the device is not formed (see reference numeral B in FIGS. 1A and 1B).

As shown in FIG. 11, the sponge 110 is held by the sponge moving device 130. The sponge moving device 130 is a perforated member moving device that moves the sponge 110 in the direction closer to the holding stage 4 and in the direction away from the holding stage 4. The sponge moving device 130 includes a holding arm 131 for holding the sponge (perforated member) 110 and a swivel motor 132 for swiveling the holding arm 131.

The sponge moving device 130 is configured to be able to move the sponge 110 between the liquid suction position shown by the solid line in FIG. 11 and the evacuation position shown by the dotted line in FIG. More specifically, when the wafer W to be polished is placed on the holding stage 4 and when the polished wafer W is removed from the holding stage 4, the sponge moving device 130 shows the sponge 110 as a dotted line in FIG. Move to the retracted position. When the polishing tape 41 polishes the wafer W on the holding stage 4, the sponge moving device 130 moves the sponge 110 to the liquid suction position shown by the solid line in FIG.

The distance L1 between the sponge 110 at the liquid suction position and the axial center O of the holding stage 4 is shorter than the radius L2 of the wafer W. In other words, at least a portion of the sponge 110 is located above the top surface of the wafer W. The distance between the lower surface of the sponge 110 and the upper surface of the wafer W is smaller than the thickness of the liquid film formed on the upper surface of the wafer W. In one example, the distance between the lower surface of the sponge 110 and the upper surface of the wafer W is in the range of 0.1 mm to 2.0 mm.

The contaminated liquid (liquid containing polishing debris) flows downstream from the contact point between the polishing tape 41 and the wafer W as the wafer W rotates. Since the sponge 110 is close to the side surface 60a on the downstream side of the polishing head 60 and close to the upper surface of the wafer W, the contaminated water comes into contact with the sponge 110 before being scattered from the wafer W. The sponge 110 absorbs the contaminated liquid, and the contaminated liquid in the sponge 110 is sucked by the liquid suction line 120.

According to this embodiment, the combination of the sponge 110 and the liquid suction line 120 can continuously remove the contaminated liquid from the wafer W. As a result, it is possible to prevent the contaminated liquid from colliding with the structure in the polishing chamber 22 and bouncing off to the upper surface of the wafer W.

As shown in FIGS. 11 and 12, the rinse liquid supply line 140 is connected to the sponge 110. The rinse liquid supply line 140 is connected to a rinse liquid supply source (not shown). The rinse liquid supply line 140 supplies the rinse liquid (for example, pure water) into the sponge 110 when the sponge 110 is in the retracted position shown by the dotted line in FIG. The rinsing liquid can wash away the polishing debris remaining in the sponge 110 and keep the sponge 110 clean. Cleaning of the sponge 110 with the rinsing liquid is performed after the polishing of the wafer W is completed.

FIG. 13 is an enlarged view of another embodiment of the polishing head 60 and the sponge 110 as viewed from above, and FIG. 14 is an enlarged view of the polishing head 60 and the sponge 110 shown in FIG. 13 as viewed from the side. Since the configuration and operation of the present embodiment not particularly described are the same as those of the embodiments shown in FIGS. 11 and 12, the duplicate description thereof will be omitted.

In the present embodiment, the sponge 110 is in contact with the bevel portion B of the wafer W during polishing of the wafer W. The sponge 110 has a curved side surface 110a that curves along the bevel portion B of the wafer W, and the curved side surface 110a comes into contact with the bevel portion B. Since the sponge 110 is made of an elastic material, when the curved side surface 110a of the sponge 110 is pressed against the bevel portion B of the wafer W by the sponge moving device 130, the curved side surface 110a is deformed and the bevel portion B of the wafer W is deformed. Is pushed into the sponge 110.

The thickness of the sponge 110 is larger than the thickness of the wafer W. When the bevel portion B of the wafer W is pushed into the sponge 110, the upper portion of the curved side surface 110a of the sponge 110 is located higher than the upper surface of the wafer W. The contaminated liquid containing the polishing debris flows on the upper surface of the wafer W and comes into contact with the sponge 110. The sponge 110 absorbs the contaminated liquid, and the contaminated liquid in the sponge 110 is sucked by the liquid suction line 120.

FIG. 15 is an enlarged view of another embodiment of the polishing head 60 and the sponge 110 as viewed from above, and FIG. 16 is an enlarged view of the polishing head 60 and the sponge 110 shown in FIG. 15 as viewed from the side. Since the configuration and operation of the present embodiment not particularly described are the same as those of the embodiments shown in FIGS. 11 and 12, the duplicate description thereof will be omitted.

In this embodiment, the sponge 110 is fixed to the polishing head 60. More specifically, the sponge 110 is fixed to the side surface 60a of the polishing head 60. In this embodiment, the sponge moving device (perforated member moving device) 130 is not provided. The sponge 110 moves integrally with the polishing head 60. That is, the sponge 110 tilts integrally with the polishing head 60, moves integrally with the polishing head 60 toward the holding stage 4 (that is, toward the wafer W), and moves away from the holding stage 4 (that is, the wafer). Move (in the direction away from W).

According to this embodiment, since the sponge moving device (perforated member moving device) 130 is not required, the manufacturing cost of the polishing device can be reduced, and the space for installing the sponge moving device (porous member moving device) 130 is available. Not needed.

FIG. 17 is an enlarged view of another embodiment of the polishing head 60 and the sponge 110 as viewed from above. Since the configuration and operation of the present embodiment not particularly described are the same as those of the embodiments shown in FIGS. 11 and 12, the duplicate description thereof will be omitted.

In this embodiment, the polishing apparatus includes a shroud cover 150 arranged around the holding stage 4. The shroud cover 150 has a shape that surrounds the outer shape of the wafer W on the holding stage 4. The shroud cover 150 surrounds the entire circumference of the wafer W, but a notch is provided in a part of the shroud cover 150 so that the polishing head 60 and the sponge 110 can access the wafer W. Further, the polishing apparatus includes a liquid absorbing member 155 fixed to the inner surface 150a of the shroud cover 150. In this embodiment, the liquid absorbing member 155 is composed of a sponge. The liquid absorbing member 155 is arranged so as to surround the wafer W on the holding stage 4.

FIG. 18 is a cross-sectional view of the shroud cover 150 and the liquid absorbing member 155 shown in FIG. The inner surface 150a of the shroud cover 150 is inclined inward toward the axial center O of the holding stage 4. The liquid absorbing member 155 is fixed to the inclined inner surface 150a of the shroud cover 150. Therefore, the inner surface of the liquid absorbing member 155 is also inclined inward toward the axis O of the holding stage 4.

During polishing of the wafer W, the liquid is supplied to the upper surface of the wafer W from the liquid supply nozzle 30. Since the wafer W is rotating, the liquid flows radially outward on the wafer W due to centrifugal force and is shaken off from the wafer W. The liquid is caught by the liquid absorbing member 155 and falls from the liquid absorbing member 155.

According to the present embodiment, the contaminated liquid (liquid containing polishing debris) generated by the contact with the polishing tape 41 is absorbed by the sponge 110, while the liquid absorbing member 155 and the shroud cover 150 polish the wafer W. It is possible to prevent the liquid supplied from the liquid supply nozzle 30 from scattering inside.

The liquid absorbing member 155 and the shroud cover 150 can also be applied to the embodiments shown in FIGS. 13 and 14, and the embodiments shown in FIGS. 15 and 16.

In each of the above-described embodiments, the polishing tape 41 is used as the polishing tool pressed against the wafer W, but the present invention is not limited to these embodiments. In one embodiment, a grindstone may be used as the polishing tool. Further, the polishing apparatus may include a plurality of polishing units 40 as shown in FIG. The embodiment shown in FIG. 19 is the same as the above-described embodiment in that the sponge 110 and the liquid suction line 120 are provided on the downstream side of the respective polishing heads 60.

The above-described embodiment is described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to carry out the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is construed in the broadest range according to the technical idea defined by the claims.

3 Board holding part 4 Holding stage 4a Holding surface 4b Groove 5 Hollow shaft 6 Ball spline bearing (linear motion bearing)
7 consecutive passages 8 rotary joints 9 vacuum line 10 nitrogen gas supply line 11 operation control unit 12 casing 14 casing 15 air cylinder (elevating mechanism)
18 Radial bearing 20 Partition 20a Transport port 21 Base plate 22 Polishing chamber 23 Shutter 30 Liquid supply nozzle 40 Polishing unit 41 Polishing tape 44 Polishing head assembly 45 Polishing tape supply mechanism 48 Supply reel 49 Winding reel 51 Motor 60 Polishing head 63 Arm 65 Motor 70 Moving table 71 Linear guide 73 Connecting plate 75 Linear actuator 76 Joint 80 Pressing member 81 First pressing member 81A Protruding blade 82 Second pressing member 83 Third pressing member 83A Protruding blade 90 Air cylinder 100 Tape feeding mechanism 103A-103G Guide roller 110 sponge (porous member)
120 Liquid suction line 123 Gas-liquid separator 125 Vacuum source 130 Sponge moving device (porous member moving device)
131 Holding arm 132 Swing motor 150 Shroud cover 155 Liquid absorbing member M1 motor (stage rotating device)

Claims (16)

A holding stage that holds the board,
A stage rotating device for rotating the holding stage and
A polishing head that presses the polishing tool against the substrate on the holding stage,
A liquid supply nozzle arranged above the holding stage and
With the porous member arranged on the downstream side of the polishing head in the rotation direction of the holding stage,
A polishing apparatus including a liquid suction line connected to the perforated member. The polishing apparatus according to claim 1, wherein the porous member is a sponge. The polishing apparatus according to claim 1 or 2, wherein at least a part of the porous member is located at a position higher than the holding stage. The polishing apparatus according to any one of claims 1 to 3, wherein the distance between the perforated member and the axis of the holding stage is shorter than the radius of the substrate. The polishing apparatus according to any one of claims 1 to 4, further comprising a porous member moving device for moving the porous member in a direction closer to the holding stage and in a direction away from the holding stage. The polishing apparatus according to any one of claims 1 to 4, wherein the porous member is fixed to the polishing head. The polishing apparatus according to any one of claims 1 to 6, further comprising a shroud cover arranged around the holding stage, wherein the shroud cover has a shape surrounding the outer shape of the substrate. The polishing apparatus according to claim 7, further comprising a liquid absorbing member fixed to the inner surface of the shroud cover. The polishing apparatus according to any one of claims 1 to 8, further comprising a rinse liquid supply line connected to the porous member. Hold the board on the holding stage,
While rotating the substrate together with the holding stage, a liquid is supplied to the upper surface of the substrate.
While pressing the polishing tool against the substrate with the polishing head to polish the substrate, the liquid is brought into contact with the porous member arranged on the downstream side of the polishing head in the rotation direction of the holding stage, and the porous is formed. A polishing method in which the liquid is sucked from a member through a liquid suction line. The polishing method according to claim 10, wherein the porous member is a sponge. The polishing method according to claim 10 or 11, wherein at least a part of the porous member is located at a position higher than the holding stage. The polishing method according to any one of claims 10 to 12, wherein the distance between the perforated member and the axis of the holding stage is shorter than the radius of the substrate. The polishing method according to any one of claims 10 to 13, wherein the porous member is non-contact with the substrate. The polishing method according to any one of claims 10 to 13, wherein the porous member is in contact with the substrate. The polishing method according to any one of claims 10 to 15, further comprising a step of supplying a rinsing liquid into the porous member to clean the porous member after polishing the substrate.

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