Slurry dispensing device for chemical mechanical polishing

Abstract

To provide a polishing liquid, e.g., abrasive slurry, during chemical mechanical polishing of a substrate.SOLUTION: An apparatus for chemical mechanical polishing includes: a rotatable platen 24 having a surface to support a polishing pad; a carrier head 70 to hold a substrate in contact with the polishing pad; and a polishing liquid distribution system 100. The polishing liquid distribution system 100 includes: a dispenser 110 positioned to deliver a polishing liquid to a portion of a polishing surface of the polishing pad; and a first barrier 120 positioned in front of the portion of the polishing surface and configured to block used polishing liquid from reaching the portion of the polishing surface.SELECTED DRAWING: Figure 2B

Description

Technical Field

[0001] The present disclosure relates to the dispensing of a polishing liquid, such as a polishing slurry, during chemical mechanical polishing of a substrate.

Background Art

[0002] Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductor, or insulating layers on a silicon wafer. Various manufacturing processes require planarization of the layers on the substrate. For example, one manufacturing step includes depositing a conductive filler layer on a patterned insulating layer to fill trenches or holes in the insulating layer. The filler layer is then polished until the raised pattern of the insulating layer is exposed. After planarization, the portions of the conductive filler layer remaining between the raised patterns of the insulating layer form vias, plugs, and lines that provide conductive paths between thin film circuits on the substrate. Planarization can also be used to smooth and remove an insulating layer over a patterned conductive layer to a desired thickness.

[0003] Chemical mechanical polishing (CMP) is a recognized method of planarization. This planarization method typically requires attaching the substrate to a carrier head. The exposed surface of the substrate is pressed against a rotating polishing pad. The carrier head applies a controllable load to the substrate to press the substrate against the polishing pad. A polishing liquid, such as a slurry having polishing particles, is supplied to the surface of the polishing pad.

Summary of the Invention

[0004] In one aspect, an apparatus for chemical mechanical polishing includes a rotatable platen having a surface for supporting a polishing pad, a carrier head for contacting and holding a substrate against the polishing pad, and a polishing liquid dispensing system. The polishing liquid dispensing system includes a dispenser arranged to supply the polishing liquid to a portion of the polishing surface of the polishing pad, and a first barrier arranged in front of the portion of the polishing surface and configured to block used polishing liquid from reaching the portion of the polishing surface.

[0005] The embodiment may include one or more of the following features.

[0006] The first barrier may be configured to contact the polishing surface during operation. The first actuator may be configured to adjust the height and / or the pressure of the first barrier with respect to the polishing surface. The first barrier may include a first wiper blade. The leading edge portion of the first wiper blade may be oriented at an acute angle with respect to the polishing surface. The first wiper blade may include a first portion having an acute angle and a second portion oriented parallel to the polishing surface. The dispenser may be arranged to supply the polishing liquid to the trailing surface of the first wiper blade. The dispenser may be arranged to supply the polishing liquid to a portion of the trailing surface on the side of the first wiper blade closer to the center of the platen.

[0007] The second barrier may be arranged behind the dispenser and configured to spread the fresh polishing liquid supplied to a part of the polishing surface by the dispenser. The second barrier may be configured to contact the polishing surface during operation. The second actuator may be configured to adjust the height and / or the pressure of the second barrier with respect to the polishing surface. The second barrier may include a second wiper blade. The leading edge portion of the second wiper blade may be oriented at an acute angle with respect to the polishing surface. The first barrier may be arranged parallel to the second barrier. The first barrier may extend to the edge of the platen, and the second barrier may be away from the edge of the platen. The second barrier may be arranged at a higher position than the first barrier, or may press the polishing pad with a lower pressure than the first barrier.

[0008] The actuator may be configured to move the first barrier and / or the second barrier laterally across the polishing pad. The reservoir may hold the polishing liquid, the dispenser may be fluidly coupled to the reservoir, and the polishing liquid may be a polishing slurry.

[0009] In another aspect, an apparatus for chemical mechanical polishing includes a rotatable platen having a surface for supporting a polishing pad, a carrier head for holding a substrate in contact with the polishing pad, and a polishing fluid dispensing system. The polishing fluid dispensing system includes a dispenser arranged to supply polishing fluid to a portion of the polishing surface of the polishing pad, and a first barrier arranged in front of the portion of the polishing surface and configured to block used polishing fluid from reaching the portion of the polishing surface. The leading surface of the first barrier is curved between an inner end of the first barrier near the center of the platen and an outer end of the first barrier near the edge of the platen.

[0010] Embodiments may include one or more of the following features.

[0011] The platen may be configured to rotate to provide a direction of movement under the first barrier, and the leading surface of the first barrier may be curved such that the concave side of the leading surface of the first barrier faces the direction of movement.

[0012] A second barrier may be arranged behind the dispenser and configured to spread fresh polishing fluid supplied to a portion of the polishing surface by the dispenser. The leading surface of the second barrier may be curved between an inner end of the second barrier near the center of the platen and an outer end of the second barrier near the edge of the platen. The leading surface of the second barrier may be curved such that the concave side of the leading surface of the second barrier faces the direction of movement. The radius of curvature of the second barrier may be smaller than the radius of curvature of the first barrier.

[0013] In another aspect, an apparatus for chemical mechanical polishing includes a rotatable platen having a surface for supporting a polishing pad, a carrier head for holding a substrate in contact with the polishing pad, and a polishing fluid dispensing system. The polishing fluid dispensing system includes a dispenser arranged to supply the polishing fluid to a portion of the polishing surface of the polishing pad, and a first barrier arranged in front of the portion of the polishing surface and configured to block used polishing fluid from reaching the portion of the polishing surface. The first barrier includes a solid first body having a first flat bottom surface and a first leading surface configured to contact the used polishing fluid.

[0014] Embodiments may include one or more of the following features.

[0015] The body can have a width along the direction of movement of the polishing pad under the first barrier that is greater than the height of the first body perpendicular to the polishing surface.

[0016] A splash guard may project from the first leading surface. The first leading surface of the first body of the first barrier may be substantially vertical, and the splash guard may project substantially horizontally.

[0017] A second barrier may be arranged behind the dispenser and configured to spread fresh polishing fluid supplied to a portion of the polishing surface by the dispenser. The second barrier can include a solid second body having a second flat bottom surface and a second leading surface configured to contact the fresh polishing fluid. The second leading surface may be oriented at an acute angle with respect to the polishing surface. The leading surface of the first body of the first barrier may be substantially vertical. The first barrier may extend to the edge of the platen, and the second barrier may be spaced from the edge of the platen. The second barrier may be arranged at a higher position than the first barrier, or may press the polishing pad with a lower pressure than the first barrier.

[0018] In another aspect, an apparatus for chemical mechanical polishing includes a rotatable platen having a surface for supporting a polishing pad, a carrier head for holding a substrate in contact with the polishing pad, and a polishing fluid dispensing system. The polishing fluid dispensing system includes a dispenser arranged to supply polishing fluid to a portion of the polishing surface of the polishing pad, a first barrier arranged in front of the portion of the polishing surface and configured to block used polishing fluid from reaching the portion of the polishing surface, a second barrier arranged behind the dispenser and configured to spread fresh polishing fluid supplied to the portion of the polishing surface by the dispenser, and a common actuator coupled to the first barrier and the second barrier to adjust the lateral positions of the first barrier and the second barrier on the polishing surface.

[0019] Embodiments may include one or more of the following features.

[0020] The common lateral actuator may include an arm having a first end coupled to the first barrier and the second barrier and a second end coupled to a rotary actuator for laterally moving the arm on the platen. A first actuator may be coupled between the first barrier and the arm, and a second actuator may be coupled between the second barrier and the arm. The first actuator may be configured to adjust the height and / or pressure of the first barrier relative to the polishing surface, and the second actuator may be configured to independently adjust the height and / or pressure of the second barrier relative to the polishing surface.

[0021] Some embodiments may include one or more of the following advantages. The uniformity of polishing can be improved. Defects can be reduced. The sensitivity of polishing to pattern density can be lowered, and dishing and erosion can be reduced. The amount of slurry used can be reduced, and thus the cost of ownership can be cut. The polishing rate can be increased. Or, while maintaining the polishing rate, the polishing pressure can be decreased.

[0022] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

[0024] Like reference symbols in the various drawings indicate like elements.

Best Mode for Carrying Out the Invention

[0025] One problem in chemical mechanical polishing is the sensitivity to pattern density, as shown, for example, by erosion and dishing. By placing a barrier to block the used slurry from returning under the substrate, the sensitivity of the polishing process to pattern density can be reduced, and dishing and erosion can be decreased.

[0026] Another problem in chemical mechanical polishing is defects. A potential cause of defects is polishing by-products. A device that blocks the used polishing liquid from returning to the area under the carrier head can help reduce the polishing by-products from reaching the substrate during polishing.

[0027] Another problem in chemical mechanical polishing is within-wafer non-uniformity (WIWNU). A potential cause of the polishing non-uniformity is the non-uniform distribution of slurry at the interface between the substrate and the polishing pad. By placing a slurry spreader in contact with the polishing pad, the slurry can be spread across the entire polishing pad in a more uniform manner.

[0028] FIG. 1 shows an example of a polishing station 20 of a chemical mechanical polishing apparatus. The polishing station 20 includes a rotatable disk-shaped platen 24 on which a polishing pad 30 is disposed. The platen 24 is operable to rotate about an axis 25. For example, a motor 22 can rotate a drive shaft 28 to rotate the platen 24.

[0029] The polishing pad 30 can be a two-layer polishing pad having a polishing layer 32 and a softer backing layer 34. A plurality of grooves 38 can be formed in the polishing surface 36 of the polishing pad 30 (see FIG. 3).

[0030] The polishing station 22 can include a pad conditioner device 40 having a conditioning disk 42 for maintaining the condition of the polishing pad 30 (see FIG. 2). The conditioning disk 42 may be disposed at an end of an arm 44 that can move the disk 42 radially across the polishing pad 30.

[0031] The carrier head 70 is operable to press and hold the substrate 10 against the polishing pad 30. The carrier head 70 is suspended from a support structure 72, such as a carousel or track, and is connected to a carrier head rotation motor 76 by a drive shaft 74 such that the carrier head can rotate about an axis 71. Optionally, the carrier head 70 can vibrate laterally, for example, on a slider on a carousel or track 72, or can vibrate by rotational vibration of the carousel itself. During operation, the platen rotates about its central axis 25, the carrier head rotates about its central axis 71, and translates laterally across the upper surface of the polishing pad 30. If there are multiple carrier heads, each carrier head 70 can independently control its polishing parameters, for example, each carrier head can independently control the pressure applied to its respective substrate.

[0032] The carrier head 70 can include a flexible membrane 80 having a substrate attachment surface that contacts the back side of the substrate 10, and a plurality of pressure chambers 82 for applying different pressures to different zones on the substrate 10, such as different radial zones. The carrier head can also include a retaining ring 84 for holding the substrate.

[0033] The polishing fluid distribution system 100 supplies and spreads a polishing fluid, such as a polishing slurry, onto the surface of the polishing pad 30. The polishing fluid distribution system 100 can also prevent used polishing fluid from returning to the substrate 10.

[0034] Referring to FIGS. 1 and 2A, a polishing fluid dispensing system 100 includes a dispenser 110 for supplying a polishing fluid 105 from a reservoir 112 to a polishing pad 30. The dispenser 110 includes one or more passageways 114 having one or more ports 116 disposed on the polishing pad 30. For example, the dispenser 110 can include a rigid body through which the passageway 114 extends, or the dispenser 110 can include a flexible tube supported by an arm. In either case, one or more holes or nozzles coupled to the passageway 114 can provide the ports 116.

[0035] The polishing fluid dispensing system 100 further includes a first barrier 120 for blocking the polished fluid that has already passed under the carrier head 70 or the conditioner disk 42 from reaching a position on the polishing pad 30 where the dispenser 110 supplies fresh polishing fluid. The first barrier 120 is disposed "in front of" the position on the polishing pad where the dispenser 110 supplies the polishing fluid 105 with respect to the direction of movement of the pad. For example, as shown in FIG. 2, when the platen 24 rotates counterclockwise as indicated by arrow A, the first barrier 120 is disposed in the clockwise direction of the dispenser 110.

[0036] In some embodiments, the first barrier 120 is disposed between the dispenser 110 and the conditioner 40 (or between the dispenser 110 and the carrier head 70 if there is no conditioner). In some embodiments, the first barrier is disposed between the conditioner 40 and the carrier head 70.

[0037] In some embodiments, the first barrier 120 is a body that contacts the surface 36 of the polishing pad 30 and generally blocks the polishing liquid from passing thereunder, except for a thin film of used polishing liquid and / or used polishing liquid 105 that may be present in the groove 38. The body of the first barrier may simply rest on the polishing pad 30 or may be clearly pressed onto the polishing pad 30, for example, by an actuator. In some embodiments, the first barrier 120 is a body that is located slightly above the surface 36 of the polishing pad 30.

[0038] The first barrier 120 can generally be an elongated body, for example, a linear body (as shown in FIG. 2A), and can be oriented substantially perpendicular to the direction of movement of the platen 24, for example, generally along the radius of the platen 24. Alternatively, the first barrier may be inclined at a significant angle, for example, 10 to 30°, with respect to the radius of the platen.

[0039] In some embodiments, the first barrier 120 is a curved body, for example, as shown in FIG. 2B. The barrier 120 can be curved such that the end closer to the outer edge of the platen 24 is ahead along the direction of movement (indicated by arrow A) than the end closer to the center of the platen. The first barrier 130 can be curved such that the concave side faces the direction of movement.

[0040] The leading surface of the first barrier 120 can be oriented at an angle of 15 to 90° with respect to the polishing surface 36 (see angle B in FIG. 3). In some embodiments, the leading surface is inclined with respect to the polishing surface at an angle of less than 90°, for example. In some embodiments, the leading surface is oriented vertically, i.e., perpendicular to the polishing surface. The leading surface of the first barrier 120 can be inclined from top to bottom in the direction of movement of the polishing pad (see arrow A in FIG. 3).

[0041] In some embodiments, the first barrier 120 is a wiper blade. The front surface of the wiper blade provides the leading surface of the first barrier 120. The wiper blade of the first barrier 120 can be formed from natural rubber or a synthetic material having similar flexibility, such as a flexible plastic, or a rigid material, such as a rigid plastic like polyetheretherketone (PEEK) or polyphenylene sulfide (PPS).

[0042] Assuming the wiper blade is a sheet of uniform width, the wiper blade of the first barrier 120 can be arranged at an angle of 15 to 90 degrees with respect to the polishing surface 36 (see angle B in FIG. 3). In some embodiments, the wiper blade of the first barrier 120 is inclined with respect to the polishing surface at an angle less than 90 degrees, for example. In some embodiments, the wiper blade of the first barrier 120 is oriented vertically, that is, at a right angle to the polishing surface. The wiper blade of the first barrier 120 can be oriented such that the wiper blade is inclined from top to bottom in the direction of movement of the polishing pad (see arrow A in FIG. 3).

[0043] In some embodiments, the first barrier 120 is suspended from a first actuator 124 that can control the vertical position of the first barrier 120 with respect to the polishing surface 36 and / or the downward force of the first barrier 120 on the polishing surface 36. Alternatively or additionally, the first actuator 124 can move the first barrier 120 laterally, for example, radially, on the polishing pad 30.

[0044] The polishing liquid distribution system 100 further includes a second barrier 130 for spreading the newly supplied polishing liquid from the dispenser 110 into a uniform film over the entire polishing surface 36. The second barrier 130 is disposed "behind" the position on the polishing pad 30 where the dispenser 110 supplies the polishing liquid 105. For example, as shown in FIG. 2, when the platen 24 rotates counterclockwise as indicated by arrow A, the second barrier 130 is disposed in the counterclockwise direction of the dispenser 110. The second barrier 130 is disposed between the dispenser 110 and the carrier head 70.

[0045] In some embodiments, the second barrier 130 is a body that contacts the surface 36 of the polishing pad 30 and generally blocks the polishing liquid from passing underneath, except for a thin film of polishing liquid that may be present in the groove 38 and / or the polishing liquid 105. The body of the second barrier 130 may simply rest on the polishing pad 30 or may be explicitly pressed onto the polishing pad 30 by, for example, an actuator. In some embodiments, the second barrier 130 is a body that is positioned slightly above the surface 36 of the polishing pad 30 while still in contact with the polishing liquid. For example, when the platen rotates, the body of the second barrier 130 can slide over the polishing liquid. In any case, the second barrier 130 can help spread the fresh polishing liquid 105a more uniformly over the entire polishing pad 30.

[0046] In some embodiments, the first barrier 120 is pressed into the polishing pad 30 at a higher pressure than the second barrier 130. In some embodiments, the first barrier 120 contacts the polishing pad 30, while the second barrier 130 is positioned slightly above the surface 36 of the polishing pad 30 while still in contact with the polishing liquid.

[0047] The second barrier 130 can generally have an elongated body, for example a linear body, and can be oriented substantially perpendicular to the direction of movement of the platen 24, for example generally along the radius of the platen 24. Alternatively, the first barrier 120 may be inclined at an angle, for example 10 to 30°, with respect to the radius of the platen.

[0048] The second barrier 130 may be parallel to the first barrier 120. Alternatively, the second barrier 130 may be inclined at a greater angle with respect to the radius of the platen than the first barrier 120.

[0049] In some embodiments, the second barrier 130 is a curved body, for example as shown in FIG. 2B. The second barrier 130 can be curved such that the end closer to the outer edge of the platen 24 is ahead along the direction of movement (indicated by arrow A) than the end closer to the center of the platen. The second barrier 130 can be curved such that the concave side faces the direction of movement.

[0050] The second barrier 130 may be equidistant from the first barrier 120 along its length. Alternatively, the radius of curvature of the second barrier 130 may be smaller than the radius of curvature of the first barrier 120. As a result, the distance between the first barrier 120 and the second barrier 130 increases radially along towards the edge of the platen 24.

[0051] The leading surface of the second barrier 130 can be oriented at an angle of 15 to 90° with respect to the polishing surface 36. In some embodiments, the leading surface of the second barrier is inclined at an angle less than 90°, for example, with respect to the polishing surface. In some embodiments, the leading surface of the second barrier is oriented vertically, that is, at a right angle to the polishing surface. The leading surface of the second barrier 130 can be inclined from top to bottom in the direction of movement of the polishing pad (see arrow A in FIG. 3).

[0052] In some embodiments, the second barrier 130 is a wiper blade. The front surface of the wiper blade provides the leading surface of the second barrier 130. The wiper blade of the second barrier 130 can be formed from a flexible material such as natural rubber or a synthetic material having similar flexibility, for example, a flexible plastic, or from a rigid material such as a rigid plastic such as polyetheretherketone (PEEK) or polyphenylene sulfide (PPS). In some embodiments, the wiper blades of the first barrier 120 and the second barrier 130 are formed of the same material.

[0053] Assuming that the wiper blade is a sheet of uniform width, the wiper blade of the second barrier 130 can be arranged to form an angle of 15 to 90 degrees between the leading surface 132 of the wiper blade and the polishing surface 36 (see FIG. 3). Arranging the wiper blade of the second barrier 130 at an angle helps to push the fresh slurry into the grooves and thus reduce the presence of the used slurry reaching the substrate.

[0054] In some embodiments, the wiper blade of the second barrier 130 is inclined with respect to the polishing surface at an angle, for example, less than 90 degrees. In some embodiments, the wiper blade of the second barrier 130 is oriented vertically, that is, at a right angle to the polishing surface. The wiper blade of the second barrier 130 can be oriented such that the wiper blade is inclined from top to bottom in the direction of movement of the polishing pad.

[0055] In some embodiments, the wiper blades of the first barrier 120 and the second barrier 130 form the same angle with the polishing surface 36. In some embodiments, the wiper blade of the first barrier 120 is oriented vertically, and the wiper blade of the second barrier 130 is inclined from top to bottom in the direction of movement of the polishing pad.

[0056] In some embodiments, the second barrier 130 is suspended from a second actuator 134 that can control the vertical position of the second barrier 130 relative to the polishing surface 36 and / or the downward force of the second barrier 130 relative to the polishing surface 36. Alternatively or additionally, the second actuator 134 can move the second barrier 130 laterally, e.g., radially, on the polishing pad 30.

[0057] Each actuator 124, 134 can be a pneumatic actuator. For example, referring to FIG. 5, each actuator can include a lower body 150 to which a barrier, e.g., a wiper blade, is fixed, an upper body 152 held by a support, e.g., an arm, and a bladder 154 confined between the lower body 150 and the upper body 152. Thus, the inflation of the bladder 154 controls the vertical position of the lower body 150 and the barriers 120, 130 and / or the pressure of the barriers 120, 130 against the polishing pad. The bottom of the bladder can be fixed to the lower body 150, e.g., by adhesion, and the top of the bladder can be fixed to the upper body 152, e.g., by retaining the rim of the bladder. Any of the actuators can be other types of actuators, e.g., a linear motor or a piezoelectric actuator.

[0058] In some embodiments, the first barrier 120 and the second barrier 130 are suspended from the same actuator.

[0059] Referring to FIGS. 4 and 5, each barrier 120, 130 can be suspended from the arm 160. For example, the upper body 152 of each actuator 124, 134 can be attached to a plate 164 fixed to the arm 160. The arm 160 can be connected to an actuator 162 configured to move the arm 160 laterally across the platen 24. For example, the actuator 162 can be a rotary actuator for moving the arm 160 in an arc (see arrow C). FIGS. 4 and 5 show a common arm for both barriers, but there can be separate arms with separate actuators.

[0060] Referring to FIG. 6, one or both of the barriers 120, 130 may be provided by a body having a flat lower surface 170 that extends parallel to the polishing surface and is pressed against the polishing pad or is still slightly separated from the polishing pad while still in contact with the polishing liquid (e.g., hydroplaning). This body can be formed of a relatively hard material, such as ceramic, or a hard plastic such as polyetheretherketone (PEEK) or polyphenylene sulfide (PPS). For example, as shown in FIG. 6, one or both of the barriers 120, 130 may be provided by the lower body 150 of the corresponding actuator 124, 134.

[0061] For any of the barriers 120, 130, the body forming the barrier can have a leading surface 172 (on the side where the polishing pad first passes underneath). In some embodiments, the leading surface is a vertical surface. In some embodiments, the leading surface 172 pushes the polishing liquid.

[0062] For any of the barriers 120, 130, the barrier can further include a splash guard 174 for preventing the splashing of the polishing liquid that collides with the leading surface 172. The splash guard 174 can be spaced vertically from the lower surface 170 and extend horizontally from the leading surface of the body in a direction opposite to the direction of rotation of the polishing pad.

[0063] Alternatively, for any of the barriers 120, 130, the barrier can include a spreader 176. The spreader 176 protrudes from the leading surface 172 of the body and has a bottom surface that is inclined with respect to the polishing surface. The angle D between the bottom surface of the spreader 176 and the polishing surface can be from 15 to 75 degrees. Similar to the inclined wiper blade, the inclined bottom surface of the spreader 176 helps to push new slurry into the groove and thus can reduce the presence of used slurry reaching the substrate.

[0064] In some embodiments, the first barrier 120 includes a splash guard and the second barrier 130 includes a spreader 176.

[0065] Returning to FIGS. 2A and 2B, the second barrier 130 may be spaced apart from the first barrier 120. In some embodiments, the wiper blade of the second barrier 130 is oriented parallel to the wiper blade of the first barrier 120. The first barrier 120 and the second barrier 130 may be the same length (along their longitudinal axes) or the second barrier 130 may be shorter than the first barrier 120. The first barrier 120 may extend completely to the edge of the platen 24 and / or the polishing pad 30, while the second barrier 130 may be spaced apart from the edge of the platen 24 and / or the polishing pad 30.

[0066] Referring to FIG. 3, in some embodiments, the dispenser 110 is arranged such that the polishing liquid 105 is supplied onto the trailing surface 126 of the wiper blade of the first barrier 120. Due to the angle of the wiper blade with respect to the polishing surface 36, the polishing liquid runs down the trailing surface 126 and flows onto the polishing pad 30 in the region between the first barrier 120 and the second barrier 130. The advantage of supplying the polishing liquid 105 onto the wiper blade is that the polishing liquid tends to flow laterally along the wiper blade, and thus the polishing liquid is supplied to the polishing pad 30 along a wider area. As a result, the polishing liquid can be spread more uniformly over the entire polishing pad 30, and the polishing uniformity can be improved. However, as shown in FIG. 1, in some embodiments, the polishing liquid 105 is directly dispensed onto the polishing pad 30 (this would be applicable to either a vertical or inclined wiper blade).

[0067] Referring to FIG. 3, during operation, the leading edge portion 122 of the first barrier 120 blocks the used polishing liquid 105b. A portion of the used polishing liquid 105b in the groove 38 of the polishing surface 36 passes under the barrier 120, but most of the used polishing liquid 105b is redirected and flows out from the edge of the polishing pad 30.

[0068] On the other hand, fresh polishing liquid 105a is supplied by the dispenser 110 to the region between the first barrier 120 and the second barrier 130. The fresh polishing liquid is similarly blocked by the leading edge portion 132 of the second barrier 130. Depending on the flow rate and the spacing between components, the fresh polishing liquid 105a may accumulate in the region between the first barrier 120 and the second barrier 130. However, a portion of the fresh polishing liquid may flow into the groove 38 and may discharge the used polishing liquid 105b. As a result, the amount of used polishing liquid reaching the substrate 10 is significantly reduced, and defects can be reduced.

[0069] Although the first barrier 120 and the second barrier 130 are shown as separate components, they may be two walls of a single connected housing. An open chamber that can accommodate the polishing liquid may be at the center of the housing between the two walls.

[0070] As shown in FIG. 3, in some embodiments, one or both barriers 120, 130, such as the wiper blade, can include a first portion 140 that is at an acute angle to the polishing surface 36 and a second portion 142 that is parallel to the polishing surface 36. The rounded portion 144 can connect the first portion 140 to the second portion 142. The barrier can be pre-formed in this shape, or the barrier can be a flexible material that is initially flat but deforms into this shape when pressed downward against the polishing surface 36. This shape helps to push the new polishing liquid 105a into the groove 38 and can improve the replacement with the used polishing liquid 105b.

[0071] By blocking the used slurry, the amount of polishing by-products reaching the substrate can be reduced, and thus the defects can be reduced. Further, without being limited to any particular theory, by increasing the amount of new slurry in the groove, the concentrations of the reaction inhibitor and the activator (for metal polishing) that contact the substrate can be increased. Thereby, the sensitivity of the polishing process to the pattern density is reduced, and dishing and erosion can be decreased. Conversely, again without being limited to any particular theory, by blocking the used slurry, the concentration of copper ions can be decreased, which saves the inhibitor for the reaction with the metal surface.

[0072] Using the controlled arrangement (shape, device dimensions, pad cover range, mounting position on the pad, etc.) of the first barrier 120 and / or the second barrier 130, the fluid can be guided away from the platen 24 or towards the substrate 10 according to the desired flow path.

[0073] By using a controlled downward force on the first barrier 120 and the second barrier 130, the ratio of fresh polishing liquid flowing under the second barrier to the used polishing liquid can be adjusted. In some embodiments, the second barrier 130 is pressed against the polishing pad 30 at a lower pressure than the first barrier 120. In some embodiments, the second barrier 130 is disposed higher above the polishing pad 30 than the first barrier 120.

[0074] By using the slurry distribution system 100 to control the distribution position or distribution pattern of the polishing liquid, the polishing profile can be adjusted and the uniformity of polishing can be improved.

[0075] The above discussion has focused on physical barriers to the polishing liquid, but it would also be possible to use air jets to block the polishing liquid. For example, an arm extends over the polishing pad and pressurized gas, such as air or nitrogen, can be directed towards the polishing pad through slots or holes at the bottom of the arm. By appropriately selecting the gas flow rate, the gas can block the polishing liquid. Additionally, it would be possible to use a vacuum to suck the used polishing liquid from the polishing pad. Such a vacuum can be applied through slots or holes at the bottom of an arm that extends laterally over the polishing pad.

[0076] A controller 90, such as a general-purpose programmable digital computer, can control the flow rate of the polishing liquid 105 from the reservoir and control the actuators 124, 134 to control the downward force and / or position of the barriers 120, 130 against the polishing pad 30. Measurements from the in-situ monitoring system are supplied to the controller 90, and the controller 90 can adjust the flow rate of the polishing liquid and / or the downward force of the barriers and / or the position of the barriers to compensate for non-uniformities in polishing.

[0077] The controller 90 can also be connected to a pressure mechanism that controls the pressure applied by the carrier head 70, a carrier head rotation motor 76 for controlling the carrier head rotation speed, a platen rotation motor 21 for controlling the platen rotation speed, or a polishing liquid distribution system 100 for controlling the slurry composition supplied to the polishing pad.

[0078] The polishing liquid distribution system can be used in various polishing systems. The polishing pad can be a circular (or other shaped) pad fixed to the platen, a tape extending between a supply roller and a take-up roller, or a continuous belt. The polishing pad may be attached to the platen, may gradually advance above the platen between polishing steps, or may be continuously driven above the platen during polishing. The pad may be fixed to the platen during polishing, or there may be a fluid bearing between the platen and the polishing pad during polishing. The polishing pad can be a standard (e.g., polyurethane with or without filler) rough pad, a soft pad, or a fixed abrasive pad.

[0079] Some embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications can be made without departing from the spirit and scope of the present invention. For example, · The preceding barrier (the first barrier) can be used without the subsequent barrier (the second barrier). · The subsequent barrier (the second barrier) can be used in the polishing system without the preceding barrier (the first barrier). · The dispenser may be supported on or be a part of the first barrier and / or the second barrier. For example, the dispenser may be a flexible tube supported on the first barrier.

[0080] Therefore, other embodiments are within the scope of the following claims.

Claims

1. 1. An apparatus for chemical mechanical polishing, comprising: a rotatable platen having a surface for supporting a polishing pad; a carrier head for holding a substrate in contact with the polishing pad; Polishing fluid distribution system and The polishing fluid distribution system comprises: a dispenser positioned to supply a polishing liquid to a portion of the polishing surface of the polishing pad; a first barrier disposed in front of the portion of the polishing surface and configured to block used polishing fluid from reaching the portion of the polishing surface; a first actuator for adjusting a height of the first barrier relative to the polishing surface and a first pressure of the first barrier relative to the polishing surface; a second barrier disposed behind the dispenser and configured to spread new polishing liquid dispensed by the dispenser onto the portion of the polishing surface; and a second actuator for adjusting a height of the second barrier relative to the polishing surface and a second pressure of the second barrier relative to the polishing surface; Including, the second leading surface of the second barrier is curved about an axis perpendicular to the polishing surface; Device.

2. 2. The apparatus of claim 1, further comprising a controller in data communication with the first actuator and the second actuator and operable to select the first pressure of the first barrier against the polishing surface and to select the second pressure of the second barrier against the polishing surface.

3. The apparatus of claim 2 , wherein the controller is configured to operate the first actuator and the second actuator such that the second barrier is positioned higher than the first barrier.

4. 3. The apparatus of claim 2, wherein the controller is configured to operate the first actuator and the second actuator such that the second barrier presses against the polishing pad with a lower pressure than the first barrier.

5. 2. The apparatus of claim 1, wherein the first barrier comprises a flexible first wiper blade and the second barrier comprises a second wiper blade.

6. 2. The apparatus of claim 1, wherein the first barrier comprises a first rigid body and the second barrier comprises a second rigid body, the first rigid body and the second rigid body each having a flat bottom surface in contact with the polishing surface.

7. 1. An apparatus for chemical mechanical polishing, comprising: a rotatable platen having a surface for supporting a polishing pad; a carrier head for holding a substrate in contact with the polishing pad; Polishing fluid distribution system and The polishing fluid distribution system comprises: a dispenser positioned to supply a polishing liquid to a portion of the polishing surface of the polishing pad; a first rigid body disposed in front of the portion of the polishing surface and having a first flat bottom surface in contact with the polishing surface and a first sidewall configured to block used polishing fluid from reaching the portion of the polishing surface; and a splash guard extending laterally from the configured first sidewall and vertically spaced from the polishing surface and the top edge of the sidewall; 13. An apparatus comprising:

8. 8. The apparatus of claim 7, wherein the polishing fluid distribution system includes a second rigid body having a second flat bottom surface in contact with the polishing surface and a second sidewall that blocks polishing fluid on the polishing surface, and a spreader extending laterally from the second sidewall.

9. The apparatus of claim 8 , wherein the splash guard extends substantially horizontally from the first side wall.

10. The apparatus of claim 8, wherein the spreader extends laterally from the second sidewall at an angle of between 15 and 75 degrees relative to the polishing surface.

11. 1. An apparatus for chemical mechanical polishing, comprising: a rotatable platen having a surface for supporting a polishing pad; a carrier head for holding a substrate in contact with the polishing pad; Polishing fluid distribution system and The polishing fluid distribution system comprises: a dispenser positioned to supply a polishing liquid to a portion of the polishing surface of the polishing pad; a first wiper blade disposed in front of the portion of the polishing surface and configured to block used polishing fluid from reaching the portion of the polishing surface; and a second wiper blade disposed behind the dispenser and configured to spread new polishing fluid dispensed by the dispenser onto the portion of the polishing surface; a surface of the first wiper blade extends downwardly toward the abrasive surface and at a first angle relative to the abrasive surface, a surface of the second wiper blade extends downwardly toward the abrasive surface and at a different angle relative to the abrasive surface than the second wiper blade, and a second leading surface of the second wiper blade is curved about an axis perpendicular to the abrasive surface.

12. The apparatus of claim 11 , wherein the first wiper blade extends substantially perpendicular to the abrasive surface.

13. The apparatus of claim 12 , wherein the second wiper blade is angled relative to the abrasive surface.

14. 1. An apparatus for chemical mechanical polishing, comprising: a rotatable platen having a surface for supporting a polishing pad; a carrier head for holding a substrate in contact with the polishing pad; Polishing fluid distribution system and The polishing fluid distribution system comprises: a dispenser positioned to supply a polishing liquid to a portion of the polishing surface of the polishing pad; a first barrier having a first length along a longitudinal axis and disposed in front of the portion of the polishing surface and configured to block used polishing fluid from reaching the portion of the polishing surface; and a second barrier having a second, different length along the longitudinal axis and disposed behind the dispenser and configured to spread new polishing liquid dispensed by the dispenser onto the portion of the polishing surface. the first barrier extends to an edge of the platen along a longitudinal axis of the first barrier and the second barrier is spaced from the edge of the platen along a longitudinal axis of the second barrier; the second leading surface of the second barrier is curved about an axis perpendicular to the polishing surface; Device.

15. 15. The apparatus of claim 14, wherein the first barrier comprises a flexible first wiper blade and the second barrier comprises a second wiper blade.

16. 15. The apparatus of claim 14, wherein the first barrier comprises a first rigid body and the second barrier comprises a second rigid body, the first rigid body and the second rigid body each having a flat bottom surface in contact with the polishing surface.

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