US20190039203A1

US20190039203A1 - Substrate processing apparatus

Info

Publication number: US20190039203A1
Application number: US16/113,103
Authority: US
Inventors: Toyonaga Toriyabe
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2017-08-01
Filing date: 2018-08-27
Publication date: 2019-02-07
Also published as: SG10201807288PA; JP2019029562A

Abstract

A substrate processing apparatus has a polishing table configured to have a polishing surface, a polishing liquid supply nozzle that supplies slurry to a slurry supply position set on the polishing table, a top ring that presses a substrate against the polishing surface of the polishing table at a polishing position set on the polishing table on a downstream side from the slurry supply position in a rotation direction of the polishing table, and a slurry returning bar 28 that is disposed at a predetermined gap from the polishing surface and extends from an outer peripheral portion of the polishing table to a central portion at a specified position on the polishing table on a downstream side from the polishing position in the rotation direction of the polishing table.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese Patent Application No. 2017-149187, filed on Aug. 1, 2017, with the Japan Patent Office, the disclosure of which is incorporated herein in their entireties by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing apparatus.

BACKGROUND

A chemical mechanical polishing (CMP) apparatus is one of the substrate processing apparatuses that perform various types of processing on substrates such as semiconductor wafers. The CMP apparatus is a kind of polishing apparatus, and the CMP apparatus is an apparatus that polishes and flattens a surface of a substrate by bringing the substrate into sliding contact with a polish pad while supplying the polish pad with slurry (polishing liquid) including abrasive grains such as silica (SiO₂) or ceria (CeO₂).
The CMP apparatus includes a polishing table that has a polishing pad, a top ring that holds a substrate, and a polishing liquid supply nozzle that supplies slurry onto the polishing table. At the time of polishing the substrate by using the CMP apparatus, the slurry is supplied onto the polishing pad from the polishing liquid supply nozzle while the substrate is held by the top ring, and the substrate is pressed against a surface (polishing surface) of the polishing pad with predetermined pressure. In this case, the substrate is brought into sliding contact with the polishing surface as the polishing table and the top ring are rotated, so that a surface of the substrate is flattened and polished as a mirror surface.
Japanese Laid-Open Patent Publication Nos. 7-237120, 10-217114, and 10-309661, Japanese Patent Nos. 2983905 and 2903980, Japanese Laid-Open Patent Publication No. 2001-121407, and Japanese Patent No. 3594357 disclose examples of substrate processing apparatuses in the related art, which are capable of reducing slurry consumption. For example, Japanese Laid-Open Patent Publication No. 7-237120 discloses a technology that contrives to reduce slurry consumption by disposing a guide having a bent-plate-shaped body on a polishing pad and suppressing slurry from flowing out from an upper side of the polishing pad. In addition, Japanese Laid-Open Patent Publication No. 2001-121407 discloses a technology that contrives to reduce slurry consumption by installing a guard plate so that the guard plate surrounds a periphery of a polishing pad, thereby suppressing slurry from flowing out to the outside at the time of polishing, and reusing the slurry on the polishing pad.

SUMMARY

A substrate processing apparatus of the present disclosure includes: a polishing table configured to have a polishing surface; a supply device configured to supply slurry to a supply position set on the polishing table; a pressing device configured to press a substrate against the polishing surface of the polishing table at a polishing position set on the polishing table on a downstream side from the supply position in a rotation direction of the polishing table; and a slurry recovery member disposed at a predetermined gap from the polishing surface and extending from an outer peripheral portion of the polishing table to a central portion of the polishing table at a specified position on the polishing table on a downstream side from the polishing position in the rotation direction of the polishing table.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view illustrating an overall configuration of a substrate processing apparatus according to an embodiment of the present disclosure.

FIG. 2 is a perspective view illustrating a configuration of a polishing module provided in the substrate processing apparatus according to the embodiment of the present disclosure.

FIG. 3 is a top plan view illustrating an arrangement relationship among a top ring on a polishing table, a polishing liquid supply nozzle, a dresser, an atomizer, and a slurry returning bar according to the embodiment of the present disclosure.

FIGS. 4A to 4F are views for explaining a path of slurry in accordance with an angle, a length, or a position of the slurry returning bar according to the embodiment of the present disclosure.

FIGS. 5A and 5B are cross-sectional side views for explaining a gap formed between a polishing surface and the slurry returning bar according to the embodiment of the present disclosure.

FIGS. 6A to 6E are views illustrating examples of cross-sectional shapes of the slurry returning bar according to the embodiment of the present disclosure.

FIG. 7 is a flowchart illustrating an example of an operation of the polishing module provided in the substrate processing apparatus according to the embodiment of the present disclosure.

FIG. 8 is a top plan view of a polishing module having a curved slurry returning bar.

DESCRIPTION OF EMBODIMENT

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here.
In the substrate processing apparatuses disclosed in Japanese Laid-Open Patent Publication Nos. 07-237120, 10-217114, and 10-309661, Japanese Patent Nos. 2983905 and 2903980, Japanese Laid-Open Patent Publication No. 2001-121407, and Japanese Patent No. 3594357, it is considered that the slurry, which has flowed out from the upper side of the polishing pad to the outside, may be reused, so that it is possible to securely reduce slurry consumption. However, since the slurry, which has been used to polish the substrate, includes polishing debris produced from the substrate, there is a problem in that polishing flaws (scratches) may be formed on a polished surface of the substrate if the slurry, which has been used to polish the substrate, is merely reused.
For example, in the substrate processing apparatus disclosed in Japanese Laid-Open Patent Publication No. 2001-121407, it is considered that the guard plate is provided to surround the periphery of the polishing pad and the slurry does not flow out to the outside, so that as polishing of the substrate progresses, the polishing debris accumulates on the polishing pad. It is considered that under this situation where the polishing debris accumulates, polishing flaws are easily formed on the polished surface of the substrate, which is highly likely to cause deterioration in polishing quality.
The present disclosure has been made in consideration of the aforementioned situations, and an object of the present disclosure is to provide a substrate processing apparatus capable of reducing slurry consumption while suppressing deterioration in polishing quality.
To achieve the aforementioned object, a substrate processing apparatus of the present disclosure includes: a polishing table configured to have a polishing surface; a supply device configured to supply slurry to a supply position set on the polishing table; a pressing device configured to press a substrate against the polishing surface of the polishing table at a polishing position set on the polishing table on a downstream side from the supply position in a rotation direction of the polishing table; and a slurry recovery member disposed at a predetermined gap from the polishing surface and extending from an outer peripheral portion of the polishing table to a central portion of the polishing table at a specified position on the polishing table on a downstream side from the polishing position in the rotation direction of the polishing table.
Further, the substrate processing apparatus further includes: a dresser disposed above the polishing table on a downstream side from the slurry recovery member in the rotation direction of the polishing table and configured to dress the polishing surface.
Further, the substrate processing apparatus further includes: a movement mechanism configured to move the slurry recovery member between the specified position on the polishing table and a retracted position set outside the polishing table.
Further, in the substrate processing apparatus, the predetermined gap is set to be smaller than a thickness of the slurry at the specified position on the polishing table.
Further, in the substrate processing apparatus, an angle defined between the slurry recovery member and a tangential direction of the polishing table is an obtuse angle at the outer peripheral portion of the polishing table, and a length of the slurry recovery member is substantially equal to a radius of the polishing table.
Further, in the substrate processing apparatus, the slurry recovery member is a bar-shaped or plate-shaped member having a straight or curved shape in a plan view.
Further, in the substrate processing apparatus, a width of the slurry recovery member in the rotation direction of the polishing table is increased at least at a bottom portion from a lower side to an upper side.
Further, in the substrate processing apparatus, a bottom surface of the slurry recovery member is a flat surface or a curved surface.
According to the present disclosure, the slurry recovery member is disposed at a predetermined gap from the polishing surface and provided to extend from the outer peripheral portion of the polishing table to the central portion at the specified position on the polishing table on the downstream side from the polishing position in the rotation direction of the polishing table. As a result, there is an effect of reducing slurry consumption while suppressing deterioration in polishing quality.
Hereinafter, a substrate processing apparatus according to an embodiment of the present disclosure will be described in detail with reference to the drawings.
[Overall Configuration of Substrate Processing Apparatus]
FIG. 1 is a top plan view illustrating an overall configuration of a substrate processing apparatus according to an embodiment of the present disclosure. A substrate processing apparatus 1 according to the present embodiment is a chemical mechanical polishing (CMP) apparatus which polishes and flattens a surface of a substrate W such as a semiconductor wafer. As illustrated in FIG. 1, the substrate processing apparatus 1 has a rectangular box-shaped housing 2. The housing 2 is formed in an approximately rectangular shape in a plan view. An interior of the housing 2 is partitioned into a loading/unloading unit 10, a polishing unit 20, and a cleaning unit 30 by partition walls. In addition, the substrate processing apparatus 1 has a substrate transport unit 40 that transports the substrate W from the loading/unloading unit 10 to the polishing unit 20, and a control unit 3 (control panel) which controls operations of the loading/unloading unit 10, the polishing unit 20, the cleaning unit 30, and the substrate transport unit 40.
The loading/unloading unit 10 has front loading units 11 that accommodate the substrates W. The multiple front loading units 11 are provided at one side in a longitudinal direction of the housing 2. The multiple front loading units 11 are arranged in a width direction of the housing 2 (a direction orthogonal to the longitudinal direction in a plan view). The front loading unit 11 is equipped with, for example, an open cassette, a standard manufacturing interface (SMIF) pod, or a front opening unified pod (FOUP). The SMIF or the FOUP is a hermetic container that accommodates therein a cassette for the substrate W and is covered by a partition wall, and the SMIF or the FOUP may maintain an environment independent of an outside space.
In addition, the loading/unloading unit 10 has a transport robot 12 that unloads the substrate W from the front loading units 11, and a motion mechanism 13 that allows the transport robot 12 to travel along the arrangement of the front loading units 11. The transport robot 12 has two upper and lower hands, and the two hands are used separately before the substrate W is processed and after the substrate W is processed. For example, the upper hand is used to return the substrate W to the front loading unit 11, and the lower hand is used to extract the substrate W, before the substrate W is processed, from the front loading unit 11.
The substrate transport unit 40 has a substrate transport path 41 that extends in the longitudinal direction of the housing 2. The substrate transport path 41 passes through a region in which the cleaning unit 30 is disposed in a plan view, such that one end 41 a thereof is in communication with the loading/unloading unit 10, and the other end 41 b thereof is in communication with the polishing unit 20. The substrate transport path 41 is provided with a slide stage that supports the substrate W, and a stage movement mechanism that moves the slide stage between the one end 41 a and the other end 41 b. The one end 41 a is a loading port for the substrate W, and the one end 41 a is closed typically by a shutter and opened when the transport robot 12 of the loading/unloading unit 10 accesses the one end 41 a. In addition, the other end 41 b is an unloading port for the substrate W, and the other end 41 b is closed typically by a shutter and opened when a transport robot RB of the polishing unit 20 accesses the other end 41 b.
The polishing unit 20 has multiple polishing modules 21 (21A, 21B, 21C, and 21D) that polish the substrate W. The multiple polishing modules 21 are arranged in the longitudinal direction of the housing 2. The polishing module 21 has a polishing table 23, a top ring 24, a polishing liquid supply nozzle 25, a dresser 26, an atomizer 27, and a slurry returning bar 28 (see FIG. 2), and flattens the surface of the substrate W by polishing the substrate W. In addition, details of the polishing module 21 will be described below.
In addition, the polishing unit 20 has a transport robot RB, a first exchanger EX1, and a second exchanger EX2. In the polishing unit 20, a first transport position TP1, a second transport position TP2, a third transport position TP3, and a fourth transport position TP4 are set in this order from the loading/unloading unit 10 along the arrangement of the multiple polishing modules 21. The first transport position TP1, the second transport position TP2, the third transport position TP3, and the fourth transport position TP4 are positions at which the substrate W is delivered to the polishing module 21A, the polishing module 21B, the polishing module 21C, and the polishing module 21D, respectively. Each of the polishing modules 21 accesses the first transport position TP1, the second transport position TP2, the third transport position TP3, or the fourth transport position TP4 by a rotation of a support arm (see FIG. 2) of the top ring 24.
The transport robot RB delivers the substrate W between the substrate transport unit 40, the first exchanger EX1, and the second exchanger EX2. The transport robot RB has a hand which holds the substrate W, a reversing mechanism which reverses the hand upside down, an extendable arm which supports the hand, an arm vertical movement mechanism which moves the arm vertically, and an arm rotation mechanism which rotates the arm about an axis extending in a vertical direction. The transport robot RB is movable between the second transport position TP2 and the third transport position TP3, and distributes the substrate W, which is received from the substrate transport unit 40, to the first exchanger EX1 or the second exchanger EX2. In addition, the transport robot RB receives the substrate W, which has been polished by the polishing modules 21, from the first exchanger EX1 or the second exchanger EX2 and delivers the substrate W to the cleaning unit 30.
The first exchanger EX1 is a mechanism that transports the substrate W between the first transport position TP1 and the second transport position TP2. The first exchanger EX1 has multiple slide stages that support the substrate W, a stage movement mechanism that moves the respective slide stages in a horizontal direction to different heights, a first pusher which is disposed at the first transport position TP1, and a second pusher disposed at the second transport position TP2. Each of the slide stages has a substantially U-shaped cutout portion such that the first pusher or the second pusher can pass through the cutout portion vertically, and each of the slide stages is moved between the first transport position TP1 and the second transport position TP2 by the stage movement mechanism. The first pusher is moved vertically at the first transport position TP1 and delivers the substrate W between the slide stage and the top ring 24 of the polishing module 21A. In addition, the second pusher is moved vertically at the second transport position TP2 and delivers the substrate W between the slide stage and the top ring 24 of the polishing module 21B.
The second exchanger EX2 is a mechanism that transports the substrate W between the third transport position TP3 and the fourth transport position TP4. The second exchanger EX2 has multiple slide stages that support the substrate W, a stage movement mechanism that moves the respective slide stages in the horizontal direction to different heights, a third pusher disposed at the third transport position TP3, and a fourth pusher disposed at the fourth transport position TP4. Each of the slide stages has a substantially U-shaped cutout portion such that the third pusher or the fourth pusher can pass through the cutout portion vertically, and each of the slide stages is moved between the third transport position TP3 and the fourth transport position TP4 by the stage movement mechanism. The third pusher is moved vertically at the third transport position TP3 and delivers the substrate W between the slide stage and the top ring 24 of the polishing module 21C. In addition, the fourth pusher is moved vertically at the fourth transport position TP4 and delivers the substrate W between the slide stage and the top ring 24 of the polishing module 21D.
The cleaning unit 30 has multiple cleaning modules 31 (31A, 31B, 31C, and 31Add) that clean the substrate W, and a drying module 32 that dries the cleaned substrate W. The multiple cleaning modules 31 and the drying module 32 are arranged in the longitudinal direction of the housing 2. A transport chamber 33 (wafer station) is provided between the cleaning module 31A and the cleaning module 31Add. The transport chamber 33 has a stage on which the substrate W delivered from the transport robot RB is placed. In addition, the cleaning unit 30 has a cleaning unit substrate transport mechanism 34 that picks up the substrate W placed on the stage in the transport chamber 33 and transports the substrate W between the multiple cleaning module 31, the drying module 32, and the transport chamber 33.
The cleaning module 31A is disposed adjacent to the transport chamber 33 and primarily cleans the substrate W. In addition, the cleaning module 31B is disposed adjacent to the cleaning module 31A and secondarily cleans the substrate W. In addition, the cleaning module 31C is disposed adjacent to the cleaning module 31B and tertiarily cleans the substrate W. The drying module 32 is disposed adjacent to the cleaning module 31C, and for example, the drying module 32 performs Rotagoni drying (isopropyl alcohol (IPA) drying). In addition, the cleaning module 31Add, which is disposed opposite to the cleaning module 31A with the transport chamber 33 interposed therebetween, is added in accordance with the cleaning specifications, and for example, the cleaning module 31Add preliminarily cleans the substrate W before the substrate W is cleaned by the cleaning modules 31A, 31B, and 31C.
For example, the cleaning module 31 is configured as a roll cleaning module which uses a roll cleaning member, a pencil cleaning module which uses a pencil cleaning member, or a two-fluid cleaning module which uses a two-fluid nozzle. The respective cleaning modules 31 may be the cleaning modules of the same type or of different types. Each of the cleaning modules 31 and the drying module 32 have a shutter-type opening through which the substrate W and the cleaning unit substrate transport mechanism 34 for transporting the substrate W may pass. After the substrate W is dried, a shutter, which is provided in a partition wall between the drying module 32 and the loading/unloading unit 10, is opened, and the substrate W is extracted from the drying module 32 by the transport robot 12.
[Configuration of Polishing Module]
FIG. 2 is a perspective view illustrating a configuration of the polishing module provided in the substrate processing apparatus according to the embodiment of the present disclosure. As illustrated in FIG. 2, the polishing module 21 has the polishing table 23 which has an upper surface (polishing surface 23a) formed by a polishing pad 22, the top ring 24 (pressing device), the polishing liquid supply nozzle 25 (supply device), the dresser 26, the atomizer 27 (processing device), and the slurry returning bar 28 (slurry recovery member).
The polishing table 23 is connected, via a table shaft, to a polishing table rotating motor (not illustrated) disposed below the polishing table 23, and the polishing table 23 is rotatable about the table shaft. The polishing pad 22 is attached onto the upper surface of the polishing table 23, and a surface of the polishing pad 22 is formed as the polishing surface 23 a that polishes the substrate W. For example, SUBA800, IC-1000, or IC-1000/SUBA400 (two-layered cross), which is manufactured by Rodel Inc., is used as the polishing pad 22. The SUBA800 is non-woven fabric made by fixing fibers with urethane resin. The IC-1000 is a pad which is made of hard foamed polyurethane and has multiple fine holes formed in a surface thereof, and the IC-1000 is also called a perforated pad.
The polishing liquid supply nozzle 25 is installed above the polishing table 23, and slurry (polishing liquid) is supplied by the polishing liquid supply nozzle 25 onto the polishing pad 22 on the polishing table 23. A functional liquid including silica (SiO₂) or ceria (CeO₂) as abrasive grains is used as the slurry. A rear end of the polishing liquid supply nozzle 25 is supported by a shaft 251, and the polishing liquid supply nozzle 25 may swing about the shaft 251.
The top ring 24 has a lower surface configured to hold the substrate W which is a polishing target, and the top ring 24 holds the substrate W and presses the substrate W against the polishing pad 22 on the polishing table 23. The top ring 24 is connected to a shaft 241, and the shaft 241 is configured to be moved vertically relative to a support arm 242. The top ring 24 is positioned by being moved vertically relative to the support arm 242 by the vertical movement of the shaft 241. The shaft 241 is configured to be rotated by being driven by a polishing head rotating motor (not illustrated). The top ring 24 is configured to be rotated about the shaft 241 by the rotation of the shaft 241.
The support arm 242 is configured to be pivotable about a shaft 243, and as the support arm 242 pivots, the top ring 24 is movable to an upper side of the polishing table 23 from a receiving position for the substrate W (the first to fourth transport positions TP1 to TP4 illustrated in FIG. 1). The top ring 24, which is moved to the upper side of the polishing table 23, presses the substrate W, which is heled on the lower surface of the top ring 24, against the polishing surface 23 a. In this case, the polishing table 23 and the top ring 24 are rotated, and the slurry is supplied onto the polishing pad 22 from the polishing liquid supply nozzle 25 provided above the polishing table 23. In this way, the slurry is supplied onto the polishing pad 22, the substrate W is pressed against the polishing pad 22, and the substrate W and the polishing pad 22 are moved relative to each other, such that an insulating film, a metal film, or the like on the substrate W is polished.
The dresser 26 has a shaft 261 and a support arm 262. The dresser 26 is connected to the shaft 261, and the shaft 261 is rotatably mounted at a tip of the support arm 262. The dresser 26 has a circular dressing surface, and hard particles are fixed onto the dressing surface by, for example, electro-deposition. Examples of the hard particles may include diamond particles and ceramic particles. The support arm 262 is pivotably supported by a shaft 263.
At the time of dressing the polishing surface 23 a, the polishing table 23 is rotated, the dresser 26 is rotated by a motor (not illustrated), and then the dresser 26 is moved downward by a lift mechanism (not illustrated), such that a lower surface of the dresser 26 is brought into sliding contact with the rotating polishing surface 23 a. In this state, as the support arm 262 swings, the dresser 26 may transversely move from an outer peripheral end to a central portion of the polishing surface 23 a. With this swinging operation, the dresser 26 may dress the entire polishing surface 23 a including the central portion of the polishing surface 23 a.
The atomizer 27 injects a fluid mixture of a liquid (e.g., pure water) and gas (e.g., nitrogen gas) or a liquid (e.g., pure water) onto the polishing surface 23 a in a mist form. The atomizer 27 is disposed above the polishing pad 22, and the atomizer 27 is disposed to extend in parallel with the polishing surface 23 a in an approximately radial direction of the polishing table 23. The atomizer 27 is configured to be fixed to the housing 2 (see FIG. 1) by a fixing arm 271 that extends to the outside of the polishing table 23. The atomizer 27 has multiple injection ports (not illustrated) which are provided in a lower surface of the atomizer 27 which faces the polishing surface 23 a, and the multiple spray ports are provided at predetermined intervals in a longitudinal direction of the atomizer 27.
The atomizer 27 is connected to a pure water supply line (not illustrated). A control valve is provided in the pure water supply line, and a control signal is input to the control valve from the control unit 3, which is a CMP controller, such that a flow rate of the pure water to be injected from the injection ports is controlled. Therefore, the pure water is injected at a flow rate optimized for the polishing surface 23 a such that foreign objects (debris of the polishing pad or solidified matters of the abrasive liquid) on the polishing surface 23 a are removed. In addition, in the case where the fluid mixture is injected from the injection ports, the atomizer 27 is also connected to a gas source.
The slurry returning bar 28 is a bar-shaped member that returns a part of the slurry, which is supplied onto the polishing pad 22 of the polishing table 23 and flows out from the upper side of the polishing pad 22 to the outside by the rotation of the polishing table 23, to the central portion of the polishing table 23. The slurry returning bar 28 is disposed between the top ring 24 and the dresser 26 so as to extend from an outer peripheral portion of the polishing table 23 toward the central portion. One end of the slurry returning bar 28 is supported by a shaft 281, and the slurry returning bar 28 is configured to be swingable about the shaft 281.
In addition, the slurry returning bar 28 is disposed above the polishing table 23 with a predetermined gap in parallel with the polishing surface 23 a. The reason that the slurry returning bar 28 is disposed with a predetermined gap from the polishing surface 23 a as described below is to suppress polishing debris (polishing debris that causes polishing flaws) adhering to the polishing pad 22 from being scraped out from the polishing pad 22 as the slurry returning bar 28 is brought into contact with the polishing pad 22. In addition, the reason is to suppress the polishing pad 22 from being abraded and decreasing in lifespan as the slurry returning bar 28 is pressed against the polishing pad 22.
In addition, since the substrate W is polished by pressing the substrate W against the polishing pad 22, it is conceivable that a large amount of polishing debris, which is produced by the polishing but does not adhere to the polishing pad 22, is present in the vicinity of the surface of the polishing pad 22. Since the slurry returning bar 28 is disposed with a predetermined gap from the polishing surface 23 a, only an upper layer portion (supernatant portion) of the slurry, which contains a small amount of polishing debris, is returned to the central portion of the polishing table 23, and a lower layer portion (stagnant portion), which contains a large amount of polishing debris, may flow out from the upper side of the polishing pad 22 to the outside.
FIG. 3 is a top plan view illustrating an arrangement relationship among the top ring on the polishing table, the polishing liquid supply nozzle, the dresser, the atomizer, and the slurry returning bar according to the embodiment of the present disclosure. As illustrated in FIG. 3, on the polishing table 23, the polishing liquid supply nozzle 25, the top ring 24, the slurry returning bar 28, the dresser 26, and the atomizer 27 are arranged in this order in a rotation direction D of the polishing table 23.
Assuming that the polishing liquid supply nozzle 25 is the uppermost stream in the rotation direction D of the polishing table 23, it may be said that the top ring 24 is disposed on a downstream side from the polishing liquid supply nozzle 25, and the slurry returning bar 28 is disposed on a downstream side from the top ring 24. In addition, it may be said that the dresser 26 is disposed on a downstream side from the slurry returning bar 28, and the atomizer 27 is disposed on a downstream side from the dresser 26.
The top ring 24, the dresser 26, and the atomizer 27 are disposed to divide a space above the polishing pad 22 into three parts in a peripheral direction based on a rotation center 0 of the polishing table 23. The polishing liquid supply nozzle 25 is disposed adjacent to the top ring 24 and the atomizer 27, and a slurry supply position P1 (supply position) is set in the vicinity of the rotation center O of the polishing table 23.
Here, when the slurry supply position P1 is too close to the rotation center O of the polishing table 23, the slurry, which is supplied to the slurry supply position P1, remains in the vicinity of the slurry supply position P1 and hardly spreads toward the outer peripheral portion of the polishing table 23. For this reason, in consideration of the spread of the slurry supplied to the slurry supply position P1, the slurry supply position P1 is disposed at a position spaced apart from the rotation center O of the polishing table 23 at a predetermined distance. In addition, the spreading degree of the slurry generally depends on a viscosity of the slurry, a rotational speed of the polishing table 23, and a distance from the rotation center O of the slurry supply position P1.
In consideration of the spread of the slurry returned to the central portion, the central portion of the polishing table 23 (a portion where the slurry is returned by the slurry returning bar 28) may be a portion closest to a circle CR having a radius which is the shortest distance between the rotation center O and the top ring 24 in a plan view based on the rotation center O of the polishing table 23, for example, as illustrated in FIG. 3.
As described above, it may be said that the top ring 24 is disposed on the downstream side from the polishing liquid supply nozzle 25. For this reason, it may be said that a polishing position P2, at which the substrate W held by the top ring 24 is polished on the polishing table 23, is set on the downstream side from the slurry supply position P1. In addition, as described above, it may be said that the slurry returning bar 28 is disposed on the downstream side from the top ring 24. For this reason, it may be said that a specified position P3, at which the slurry returning bar 28 is disposed above the polishing table 23, is set on the downstream side from the polishing position P2.
The slurry returning bar 28 is configured to be swingable about the shaft 281. The shaft 281 constitutes a movement mechanism DR that moves the slurry returning bar 28 between the specified position P3 and a retracted position P4 set outside the polishing table 23. When the shaft 281 rotates, the slurry returning bar 28 swings about the shaft 281 as illustrated in FIG. 3.
At the outer peripheral portion of the polishing table 23 (a position P5 at which the slurry returning bar 28 intersects an outer edge portion of the polishing table 23 in a plan view), an angle θ, which is defined between a longitudinal direction of the slurry returning bar 28 and a tangential direction of the polishing table 23, is set as an obtuse angle (an angle larger than 90° and smaller than 180°). The reason is to allow the slurry, which flows out in the tangential direction from the upper side of the polishing pad 22, to be effectively directed toward the central portion of the polishing table 23 because the flow-out direction of the slurry flowing out from the upper side of the polishing pad 22 to the outside is a direction substantially along the tangential direction of the polishing table 23. In the example illustrated in FIG. 3, the angle θ is set as an angle at which a part of a tip portion of the slurry returning bar 28 is included in the circle CR in a plan view, in order to effectively direct the slurry toward the central portion of the polishing table 23.
A length of the slurry returning bar 28 (a length of a portion positioned above the polishing table 23 in a plan view) is equal to a radius of the polishing table 23. The reason is that the slurry returning bar 28 delivers, in the longitudinal direction, a part of the slurry flowing out from the upper side of the polishing pad 22 to the outside and returns the part of the slurry to the central portion of the polishing table 23. In addition, the length of the slurry returning bar 28 is not uniquely determined only based on the radius of the polishing table 23 but is determined in consideration of the aforementioned angle (an angle defined by the tangential direction of the polishing table 23) as well.
FIGS. 4A to 4F are views for explaining a path of slurry in accordance with an angle, a length, or a position of the slurry returning bar according to the embodiment of the present disclosure. In addition, for ease of understanding, in FIGS. 4A to 4F, a path of the slurry, which flows out to the outside through a gap between the slurry returning bar 28 and the polishing surface 23 a, is omitted. First, when the angle, the length, and the position of the slurry returning bar 28 are suitable, the slurry flows along the path indicated by the broken line arrow in the drawing and returned to the vicinity (central portion) of the rotation center O of the polishing table 23, as illustrated in FIG. 4A. The slurry, which is returned to the central portion of the polishing table 23, is reused to polish the substrate W (not illustrated in FIGS. 4A to 4F) held by the top ring 24.
In contrast, when the angle of the slurry returning bar 28 is not suitable, the slurry flows along the path indicated by the broken line arrows in the drawings and flows out from the upper side of the polishing pad 22 to the outside as illustrated in FIGS. 4B and 4C. Specifically, when the angle of the slurry returning bar 28 is too small, the slurry flows along the slurry returning bar 28 and directed in the longitudinal direction of the slurry returning bar 28, but flows out from the upper side of the polishing pad 22 to the outside without being returned to the central portion of the polishing table 23. When the angle of the slurry returning bar 28 is too large, the slurry is directed toward the outside of the polishing pad 22 by the slurry returning bar 28 and flows out from the upper side of the polishing pad 22 to the outside.
In addition, when the length of the slurry returning bar 28 is not suitable, the slurry flows along the path indicated by the broken line arrows in the drawings and flows out from the upper side of the polishing pad 22 to the outside as illustrated in FIGS. 4D and 4E. Specifically, when the length of the slurry returning bar 28 is too long, the slurry flows along the slurry returning bar 28 and directed toward the central portion of the polishing pad 22, but the slurry flows along the slurry returning bar 28 even though the slurry reaches the central portion of the polishing pad 22, and as a result, the slurry flows out from the upper side of the polishing pad 22 to the outside. When the length of the slurry returning bar 28 is too short, the slurry flows slightly along the slurry returning bar 28, but flows out from the upper side of the polishing pad 22 to the outside without being returned to the central portion of the polishing table 23.
In addition, when the position of the slurry returning bar 28 is not suitable, the slurry flows along the path indicated by the broken line arrow in the drawing and flows out from the upper side of the polishing pad 22 to the outside as illustrated in FIG. 4F. Specifically, the slurry, which passes through a path R1 in the vicinity of the outer peripheral portion of the polishing pad 22, does not flow along the slurry returning bar 28, but flows out as it is from the upper side of the polishing pad 22 to the outside. The slurry, which passes through a path R2 in the vicinity of the central portion of the polishing pad 22, also hardly flows along the slurry returning bar 28, but flows out from the upper side of the polishing pad 22 to the outside.
As described above, when all of the angle, the length, and the position of the slurry returning bar 28 are suitable, the slurry is returned to the vicinity (central portion) of the rotation center O of the polishing table 23 and reused to polish the substrate W, as illustrated in FIG. 4A. In contrast, when any one of the angle, the length, and the position of the slurry returning bar 28 is not suitable, the slurry flows out from the upper side of the polishing pad 22 to the outside without being returned to the vicinity (central portion) of the rotation center O of the polishing table 23 as illustrated in FIGS. 4B to 4F.
FIGS. 5A and 5B are cross-sectional side views for explaining a gap formed between the polishing surface and the slurry returning bar according to the embodiment of the present disclosure. As described above, the slurry returning bar 28 is disposed to be spaced apart from the polishing pad 22 in order to suppress polishing debris, which mainly adheres to the polishing pad 22, from being scraped out from the polishing pad 22. Meanwhile, the slurry returning bar 28 serves to return a part of slurry SL to the central portion of the polishing table 23. For this reason, a gap formed between the polishing pad 22 and the slurry returning bar 28 is set to be smaller than a thickness T of the slurry SL at the specified position P3 on the polishing table 23.
FIG. 5A is a cross-sectional side view illustrating a state where the gap between the polishing pad 22 and the slurry returning bar 28 is set to be small. When the gap between the polishing pad 22 and the slurry returning bar 28 is set to be small, the amount of slurry SL, which passes through the gap, is decreased. For this reason, the slurry SL is raised on the upstream side of the slurry returning bar 28 in the rotation direction D of the polishing table 23, as illustrated.
FIG. 5B is a cross-sectional side view illustrating a state where the gap between the polishing pad 22 and the slurry returning bar 28 is set to be large. When the gap between the polishing pad 22 and the slurry returning bar 28 is set to be large, the amount of slurry SL, which passes through the gap, is increased. For this reason, the slurry SL is substantially flat even on the upstream side of the slurry returning bar 28 in the rotation direction D of the polishing table 23.
The slurry returning bar 28 comes into contact with the slurry SL without coming into contact with the polishing pad 22 even in the case where the gap between the polishing pad 22 and the slurry returning bar 28 is set to be small as illustrated in FIG. 5A and even in the case where the gap between the polishing pad 22 and the slurry returning bar 28 is set to be large as illustrated in FIG. 5B. That is, the slurry returning bar 28 is disposed such that a lowermost portion of the slurry returning bar 28 is positioned within the thickness T of the slurry SL.
FIGS. 6A to 6E are views illustrating examples of cross-sectional shapes of the slurry returning bar according to the embodiment of the present disclosure. For example, a cross-sectional shape of the slurry returning bar 28 may be a circular shape (FIG. 6A), a rounded quadrangular shape (FIG. 6B), a home base shape (FIG. 6C), a longitudinally oblong oval shape (FIG. 6D), an inverted trapezoidal shape (FIG. 6E), or the like. That is, the cross-sectional shape of the slurry returning bar 28 may be a shape in which a width in the rotation direction D of the polishing table 23 is increased, at least at a bottom portion, from the lower side to the upper side.
The reason that the cross-sectional shape of the slurry returning bar 28 is set to the aforementioned shape (the shape that increases, at least the bottom portion, from the lower side to the upper side) is to mainly cause the adhering slurry to easily drop, thereby suppressing the occurrence of polishing flaws. When the slurry attached to the slurry returning bar 28 is peeled after being dried, this causes the occurrence of polishing flaws, and therefore, the occurrence of polishing flaws is suppressed by dropping the slurry before the slurry attached to the slurry returning bar 28 is dried. The surface of the slurry returning bar 28 may be subjected to fluorine processing in order to make it easy to drop the attached slurry.
Since it is necessary to provide the aforementioned gap between the slurry returning bar 28 and the polishing pad 22, it is desirable that the slurry returning bar 28 does not warp in the vertical direction. In addition, a height of the slurry returning bar 28 may be set to a height at which the slurry does not climb over the slurry returning bar 28. A bottom surface of the slurry returning bar 28 may be a flat surface (see FIGS. 6B, 6C, and 6E) or a curved surface (see FIGS. 6A and 6D). In addition, there may be provided a unit that automatically washes out the slurry attached to the slurry returning bar 28 by applying pure water to the slurry returning bar 28.
[Operation of Polishing Module]
FIG. 7 is a flowchart illustrating an example of an operation of the polishing module provided in the substrate processing apparatus according to the embodiment of the present disclosure. The series of processing of the flowchart illustrated in FIG. 7 are performed each time the substrate W is delivered to the top ring 24 at the receiving position for the substrate W (the first to fourth transport positions TP1 to TP4 illustrated in FIG. 1). In addition, the series of processing illustrated in FIG. 7 are performed under control of the control unit 3 (see FIG. 1).
When the substrate W is delivered to the top ring 24 at the receiving position for the substrate W, the top ring 24 is moved to the side above the polishing table 23 by the pivot of the support arm 242. Therefore, the top ring 24, which holds the substrate W, is disposed above the polishing position P2 illustrated in FIG. 3 (step S11). When the top ring 24 is completely disposed, the polishing table 23, the top ring 24, and the dresser 26 begin to rotate, and the slurry begins to be supplied from the polishing liquid supply nozzle 25 to the slurry supply position P1 set on the polishing table 23 (step S12).
Subsequently, as the shaft 281, which constitutes the movement mechanism DR, swings, the slurry returning bar 28 disposed at the retracted position P4 is disposed at the specified position P3 set on the polishing table 23 (step S13). When the slurry returning bar 28 is completely disposed, the substrate W held by the top ring 24 is polished (step S14). Specifically, as the shaft 241 moves downward relative to the support arm 242, the substrate W held on the lower surface of the top ring 24 is pressed against the polishing surface 23 a of the polishing pad 22.
The substrate W is polished as the slurry is supplied onto the polishing pad 22 and the polishing table 23 and the top ring 24, which holds the substrate W in the state where the substrate W is pressed against the polishing surface 23 a of the polishing pad 22, are rotated. In the middle of polishing the substrate W, a part of the slurry, which is supplied onto the polishing table 23 and passes a periphery or a bottom portion of the substrate W, is returned to the central portion of the polishing table 23 by the slurry returning bar 28 and reused to polish the substrate W.
The dresser 26 brings a rotating unit, to which hard particles such as diamond particles or ceramic particles are fixed, into contact with the polishing surface 23 a, and swings while rotating the rotating unit, thereby uniformly dressing the entire polishing surface 23 a and forming the flat polishing surface 23 a. The atomizer 27 washes out polishing debris or abrasive grains remaining on the polishing surface 23 a with a high-pressure fluid, thereby purifying the polishing surface 23 a, and dressing the polishing surface by the dresser 26 with mechanical contact, that is, regenerating the polishing surface 23 a.
When the substrate W is completely polished, the slurry returning bar 28, which is disposed at the specified position P3 set on the polishing table 23, is retracted to the retracted position P4 as the shaft 281, which constitutes the movement mechanism DR, swings (step S15). Subsequently, the polishing table 23, the top ring 24, and the dresser 26 stop rotating, and the supply of the slurry from the polishing liquid supply nozzle 25 to the slurry supply position P1 set on the polishing table 23 is also stopped (step S16).
When the aforementioned processing is finished, the substrate W is extracted. Specifically, as the shaft 241 moves upward relative to the support arm 242, the top ring 24 is moved to the side above the polishing table 23. Further, as the support arm 242 pivots, the top ring 24, which is moved to the side above the polishing table 23, is moved to the receiving position for the substrate W, and the substrate W held by the top ring 24 is delivered to the receiving position. In this way, the substrate W is polished.
As described above, according to the present embodiment, the slurry returning bar 28 is disposed at a predetermined gap from the polishing surface 23 a and extends to the central portion from the outer peripheral portion of the polishing table 23, at the specified position P3 on the downstream side from the polishing position P2 in the rotation direction D of the polishing table 23. Therefore, a part of the slurry flowing out from the upper side of the polishing pad 22 to the outside is returned to the central portion of the polishing table 23 and reused to polish the substrate W. For this reason, it is possible to reduce slurry consumption while suppressing deterioration in polishing quality.
While the substrate processing apparatus according to the embodiment of the present disclosure has been described above, the present disclosure may be freely changed within the scope of the present disclosure without being limited to the aforementioned embodiment. For example, in the embodiment, descriptions have been made on an example in which the slurry returning bar 28 is a straight bar-shaped member in a plan view. However, the slurry returning bar 28 may have a straight shape or a curved shape in a plan view, and the slurry returning bar 28 may be a bar-shaped member or a plate-shaped member.
In addition, the angle θ, which is defined between the longitudinal direction of the slurry returning bar 28 and the tangential direction of the polishing table 23 at the outer peripheral portion of the polishing table 23 (the position P5 at which the slurry returning bar 28 intersects the outer edge portion of the polishing table 23 in a plan view), and the length of the slurry returning bar 28 may be set to an appropriate angle and an appropriate length in accordance with a shape of the slurry returning bar 28 in a plan view. In the case where the shape of the slurry returning bar 28 is a curved shape in a plan view, the angle may be set to an obtuse angle (an angle larger than 90° and smaller than 180°) similar to the case where the shape of the slurry returning bar 28 is a straight shape in a plan view. For example, the angle may be set to about 160°.
FIG. 8 is a top plan view of a polishing module having a curved slurry returning bar. In addition, FIG. 8 is a view corresponding to FIG. 3. As illustrated in FIG. 8, the slurry returning bar 28 is disposed on the downstream side of the top ring 24 and curved along the top ring 24 in a plan view. An angle θ in the drawing (an angle defined between a tangential direction of the slurry returning bar 28 and a tangential direction of the polishing table 23 at the position P5) is set to an obtuse angle, and a part of a tip portion of the slurry returning bar 28 is included within the circle CR in a plan view.
From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

What is claimed is:

1. A substrate processing apparatus comprising:

a polishing table configured to have a polishing surface;

a supply device configured to supply slurry to a supply position set on the polishing table;

a pressing device configured to press a substrate against the polishing surface of the polishing table at a polishing position set on the polishing table on a downstream side from the supply position in a rotation direction of the polishing table; and

a slurry recovery member disposed at a predetermined gap from the polishing surface and extending from an outer peripheral portion of the polishing table to a central portion of the polishing table at a specified position on the polishing table on a downstream side from the polishing position in the rotation direction of the polishing table.

2. The substrate processing apparatus of claim 1, further comprising:

a dresser disposed above the polishing table on a downstream side from the slurry recovery member in the rotation direction of the polishing table and configured to dress the polishing surface.

3. The substrate processing apparatus of claim 1, further comprising:

a movement mechanism configured to move the slurry recovery member between the specified position on the polishing table and a retracted position set outside the polishing table.

4. The substrate processing apparatus of claim 1, wherein the predetermined gap is set to be smaller than a thickness of the slurry at the specified position on the polishing table.

5. The substrate processing apparatus of claim 1, wherein an angle defined between the slurry recovery member and a tangential direction of the polishing table is an obtuse angle at the outer peripheral portion of the polishing table, and

a length of the slurry recovery member is substantially equal to a radius of the polishing table.

6. The substrate processing apparatus of claim 1, wherein the slurry recovery member is a bar-shaped or plate-shaped member having a straight or curved shape in a plan view.

7. The substrate processing apparatus of claim 1, wherein a width of the slurry recovery member in the rotation direction of the polishing table is increased at least at a bottom portion from a lower side to an upper side.

8. The substrate processing apparatus of claim 1, wherein a bottom surface of the slurry recovery member is a flat surface or a curved surface.