Patent Grant
11890716
This application relates to a polishing unit, a substrate processing apparatus, and a polishing method. This application claims priority from Japanese Patent Application No. 2019-233037 filed on Dec. 24, 2019. The entire disclosure including the descriptions, the claims, the drawings, and the abstracts in Japanese Patent Application No. 2019-233037 is herein incorporated by reference.
In manufacturing a semiconductor device, a chemical mechanical polishing (CMP) apparatus is used for planarization of a surface of a substrate. The substrate used in the manufacture of the semiconductor device often has a circular plate shape. Not limited to the semiconductor device, a demand for flatness in planarization of a surface of a rectangular substrate, such as a CCL substrate (Copper Clad Laminate substrate), a PCB (Printed Circuit Board) substrate, a photomask substrate, and a display panel, has increased. A demand for planarizing a surface of a package substrate on which electronic devices, such as a PCB substrate, are disposed also has increased.
A chemical mechanical polishing device includes a top ring that holds a substrate and a polishing table to which a polishing pad is attached, and is configured to polish the substrate by pressing the substrate against the polishing pad while rotating the top ring and the polishing table. Here, in the polishing of the substrate, the substrate comes off from the top ring to slip outside the top ring in some cases. In contrast, for example, PTL 1 discloses that a photoelectric sensor is used to detect the slip out of the substrate.
In the technique disclosed in PTL 1, a light is emitted toward a detection area set on a polishing pad to detect the slip out of the substrate based on a change of an amount of the light reflected from the detection area. That is, since the polishing pad and the substrate are different in light reflectance, the amount of the reflected light from the detection area changes when the substrate comes off from the top ring to appear in the detection area, thereby determining that the substrate has come off from the top ring when the change is detected. PTL 1 also discloses the detection of the slip out of the substrate using a color difference sensor.
However, the technique disclosed in PTL 1 still has a room to improve the accuracy of detecting the slip out of the substrate. That is, since the substrate as a process target of the polishing device has a variety in thickness and base material (material) and is large in variation of the reflection-light amount, the photoelectric sensor possibly makes a false detection in the detection method using the light-amount difference. While the polishing device uses a slurry (polishing liquid) to polish the substrate, shavings are generated from the substrate to be mixed in the slurry during the polishing, or the slurry is discolored by a chemical reaction or the like in some cases. This possibly causes the sensor to make a false detection due to flowing of the slurry in which the shavings are mixed or the discolored slurry into the detection area even when the color difference sensor is used.
Therefore, this application has one object to improve an accuracy of detecting a slip out of a substrate from a top ring.
One embodiment discloses a polishing unit that includes a polishing table, a top ring, a light emitting member, a slip-out detector, and an elimination mechanism. A polishing pad for polishing a substrate is attached to the polishing table. The top ring holds the substrate to press the substrate against the polishing pad. The light emitting member emits a light to a detection area on the polishing pad. The slip-out detector detects a slip out of the substrate from the top ring based on the light reflected from the detection area. The elimination mechanism eliminates a polishing liquid flowing into the detection area.
The following describes embodiments of a substrate processing apparatus according to the present invention with reference to the attached drawings. In the attached drawings, the same or similar reference numerals are attached to the same or similar components, and overlapping description regarding the same or similar components may be omitted in the description of the respective embodiments. Features illustrated in the respective embodiments are applicable to other embodiments in so far as they are consistent with one another.
<Loading Unit>
The loading unit 100 is a unit for introducing a substrate WF before processes, such as polishing and cleaning, are performed into the substrate processing apparatus 1000. In the one embodiment, the loading unit 100 is configured to be compliant to a mechanical equipment interface standard (IPC-SMEMA-9851) of Surface Mount Equipment Manufacturers Association (SMEMA).
In the illustrated embodiment, a conveyance mechanism of the loading unit 100 includes a plurality of conveyance rollers 202 and a plurality of roller shafts 204 to which the conveyance rollers 202 are mounted. In the embodiment illustrated in
<Conveyance Unit>
The substrate processing apparatus 1000 illustrated in
The illustrated conveyance unit 200 includes a plurality of conveyance rollers 202 to convey the substrate WF. By rotating the conveyance rollers 202, the substrate WF on the conveyance rollers 202 can be conveyed in a predetermined direction. The conveyance rollers 202 of the conveyance unit 200 may be formed of a conductive polymer, or formed of a non-conductive polymer. The conveyance rollers 202 are driven by a motor (not illustrated). The substrate WF is conveyed to a substrate transfer position by the conveyance rollers 202.
In the one embodiment, the conveyance unit 200 includes a cleaning nozzle 284. The cleaning nozzle 284 is connected to a supply source (not illustrated) of a cleaning liquid. The cleaning nozzle 284 is configured to supply the cleaning liquid to the substrate WF conveyed by the conveyance rollers 202.
<Drying Unit>
The drying unit 500 is a device to dry the substrate WF. In the substrate processing apparatus 1000 illustrated in
The drying unit 500 includes a nozzle 530 to inject a gas toward the substrate WF conveyed on the conveyance rollers 202. The gas may be, for example, a compressed air or nitrogen. By blowing off water droplets on the conveyed substrate WF by the drying unit 500, the substrate WF can be dried.
<Unloading Unit>
The unloading unit 600 is a unit to carry out the substrate WF after the processes, such as the polishing and the cleaning, are performed outside the substrate processing apparatus 1000. In the substrate processing apparatus 1000 illustrated in
<Polishing Unit>
As illustrated in
A polishing liquid supply nozzle 354 is disposed above the polishing table 350, and the polishing liquid supply nozzle 354 is configured to supply the polishing liquid on the polishing pad 352 on the polishing table 350. As illustrated in
While not illustrated in
The top ring 302 is connected to a top ring shaft 18, and the top ring shaft 18 is configured to be moved up and down with respect to a swing arm 360 by an up-and-down motion mechanism 319. The top ring 302 is configured to be entirely moved up and down with respect to the swing arm 360 by the up-and-down motion of the top ring shaft 18 and positioned. The top ring shaft 18 is configured to be rotated by the driving of a top ring rotation motor (not illustrated). The top ring 302 is configured to be rotated about the top ring shaft 18 by the rotation of the top ring shaft 18. A rotary joint 323 is mounted to an upper end of the top ring shaft 18.
Various kinds of the polishing pad are available in the market, and for example, SUBA800 (“SUBA” is registered trademark), IC-1000, and IC-1000/SUBA400 (two-layer cloth) manufactured by Nitta Haas Incorporated, and Surfin xxx-5, Surfin 000, and the like (“Surfin” is registered trademark) manufactured by FUJIMI INCORPORATED are included. SUBA800, Surfin xxx-5, and Surfin 000 are nonwoven fabrics made of fibers hardened with urethane resin, and IC-1000 is a rigid polyurethane foam (single layer). The polyurethane foam is porous, and many fine hollows or holes are provided in its surface.
The top ring 302 is configured to hold the rectangular substrate in its lower surface. The swing arm 360 is configured to be turnable about a spindle 362. The top ring 302 is movable between the substrate transfer position of the conveyance unit 200 described above and a position above the polishing table 350 by the turn of the swing arm 360. By moving down the top ring shaft 18, the top ring 302 can be moved down to press the substrate to the surface (polishing surface) 352a of the polishing pad 352. At this time, the top ring 302 and the polishing table 350 are each rotated, and the polishing liquid is supplied on the polishing pad 352 from the polishing liquid supply nozzle 354 disposed above the polishing table 350 and/or from the opening portion 355 provided to the polishing table 350. Thus, the substrate WF is pressed to the polishing surface 352a of the polishing pad 352, thereby allowing the polishing of the surface of the substrate. The swing arm 360 may be fixed or swung such that the top ring 302 passes through the center of the polishing pad 352 (covers the through-hole 357 of the polishing pad 352) during the polishing of the substrate WF.
The up-and-down motion mechanism 319 that moves the top ring shaft 18 and the top ring 302 up and down includes a bridge 28, a ball screw 32, a support table 29, and a servo motor 38. The bridge 28 rotatably supports the top ring shaft 18 via a bearing 321. The ball screw 32 is mounted to the bridge 28. The support table 29 is supported by a support pillar 130. The servo motor 38 is disposed on the support table 29. The support table 29 that supports the servo motor 38 is secured to the swing arm 360 via the support pillar 130.
The ball screw 32 includes a screw shaft 32a connected to the servo motor 38, and a nut 32b with which the screw shaft 32a screws. The top ring shaft 18 is configured to move up and down integrally with the bridge 28. Accordingly, when the servo motor 38 is driven, the bridge 28 moves up and down via the ball screw 32, thereby moving the top ring shaft 18 and the top ring 302 up and down. The polishing unit 300 includes a distance measuring sensor 70 as a position detection unit that detects a distance to a lower surface of the bridge 28, that is, a position of the bridge 28. By detecting the position of the bridge 28 by the distance measuring sensor 70, the position of the top ring 302 can be detected. The distance measuring sensor 70 constitutes the up-and-down motion mechanism 319 together with the ball screw 32 and the servo motor 38. The distance measuring sensor 70 may be a laser sensor, an ultrasonic wave sensor, an overcurrent sensor, or a linear scale sensor. The devices in the polishing unit including the distance measuring sensor 70 and the servo motor 38 are each configured to be controlled by the control device 900.
The polishing unit 300 according to the one embodiment includes a dressing unit 356 that dresses the polishing surface 352a of the polishing pad 352. As illustrated in
The swing arm 55 is configured to be driven by a motor (not illustrated) to turn about a spindle 58. The dresser shaft 51 is disposed to be opposed to the polishing pad 352 and rotated by the driving of a motor not illustrated in
The dressing of the polishing surface 352a of the polishing pad 352 is performed as follows. The dresser 50 is pressed to the polishing surface 352a by the air cylinder 53, and the pure water is simultaneously supplied to the polishing surface 352a from a pure water supply nozzle (not illustrated). In this state, the dresser 50 rotates about the dresser shaft 51 to bring the lower surface (diamond particles) of the dressing member 50a into sliding contact with the polishing surface 352a. Thus, the polishing pad 352 is scraped off from the dresser 50, and the polishing surface 352a is dressed.
<Slip-Out Detector>
More specifically, the slip-out detector 370 can detect the slip out of the substrate WF from the top ring 302 based on a change of a color of the light reflected from the detection area 372. That is, the slip-out detector 370 emits the light to the detection area 372 of the polishing pad 352 as a reference before the polishing process of the substrate WF is performed, and registers a reference color of the polishing pad based on the light reflected from the detection area 372. The slip-out detector 370 compares the color based on the light reflected from the detection area 372 of the polishing pad 352 with the reference color during the polishing process of the substrate WF.
Thus, when the sensitivity of color difference based on the reflected light from the detection area 372 is significantly different between the case where the polishing pad 352 is present (the substrate WF is absent) in the detection area 372 and the case where the substrate WF is present in the detection area 372, the slip-out detector 370 can accurately detect the slip out of the substrate WF from the top ring 302. As illustrated in the experimental result in
Meanwhile, when the colors of the polishing pad 352 and the substrate WF are close or when a disturbance has an influence, the difference of the sensitivity of color difference based on the reflected light from the detection area 372 possibly decreases between the case where the polishing pad 352 is present (the substrate WF is absent) in the detection area 372 and the case where the substrate WF is present in the detection area 372. In this case, the slip out of the substrate WF from the top ring 302 possibly cannot be detected regardless of the presence of the substrate WF in the detection area 372 depending on the setting of the threshold value for the slip-out detection.
In contrast to, the slip-out detector 370 can be configured to detect the slip out of the substrate WF from the top ring 302 based on the change of the amount of the light reflected from the detection area 372 in addition to the change of the color of the light reflected from the detection area 372. That is, the slip-out detector 370 emits the light to the detection area 372 of the polishing pad 352 as a reference before the polishing process of the substrate WF is performed, and registers a reference amount of the light reflected from the detection area 372. The slip-out detector 370 compares the amount of the light reflected from the detection area 372 of the polishing pad 352 with the preliminarily registered reference amount of the light during the polishing process of the substrate WF. When the substrate WF comes off from the top ring 302 and enters the detection area 372, the light amount different from the amount of the reflected light from the polishing pad 352 is detected. Therefore, the slip-out detector 370 can detect the slip out of the substrate WF from the top ring 302.
<Elimination Mechanism>
As illustrated in
While the example in which the elimination mechanism 380 includes the purge mechanism 384 is indicate in this embodiment, the configuration is not limited to this.
Next, a description will be given of a procedure of a polishing method including the slip-out detection of the substrate WF according to the embodiment.
Subsequently, the polishing method starts the polishing of the substrate WF (polishing step S104). That is, the polishing method rotates the polishing table 350 while rotating the top ring 302, and presses the substrate WF held onto the top ring 302 to the polishing pad 352. Subsequently, the polishing method determines whether the slip-out of the substrate WF is detected or not (Step S105). When the slip-out of the substrate WF is detected by the slip-out detector 370 (Step S105, Yes), the polishing method safely stops the operation of the substrate processing apparatus 1000 (Step S106).
Meanwhile, when the slip-out of the substrate WF is not detected by the slip-out detector 370 (Step S105, No), and a predetermined polishing time has passed, the polishing method terminates the polishing of the substrate WF (Step S107). Subsequently, the polishing method stops the purge in the slip-out detection area (Step S108). Subsequently, the polishing method stops the emitting and receiving of the light by the slip-out detector 370 to stop the slip-out detection (Step S109). Subsequently, in the polishing method, the top ring 302 delivers the substrate WF to the conveyance unit 200 (Step S110).
Subsequently, the polishing method counts a cumulative number of polishing processes in the polishing unit 300 (Step S111). Subsequently, the polishing method determines whether the counted cumulative number of polishing processes has reached a preliminarily set number of polishing processes (threshold value) or not (Step S112). When the counted cumulative number of polishing processes does not exceed the preliminarily set number of polishing processes (threshold value) (Step S112, No), the polishing method returns to Step S101 and repeats the process to the substrate WF as a next process target. Meanwhile, when the counted cumulative number of polishing processes exceeds the preliminarily set number of polishing processes (threshold value) (Step S112, Yes), the polishing method resets the reference color of the slip-out detector 370 and automatically reregisters the reference color (Step S113). That is, the slip-out detector 370 assumes the current polishing pad 352 as the reference polishing pad, emits the light to the detection area 372 of this polishing pad 352, and registers the reference color of the polishing pad based on the light reflected from the detection area 372. The polishing method returns to Step S101 after Step S113, and repeats the process to the substrate WF as the next process target. Note that the order of the above-described processing steps may be changed, or they may be simultaneously executed.
The embodiments of the present invention have been described above in order to facilitate understanding of the present invention without limiting the present invention. The present invention can be changed or improved without departing from the gist thereof, and of course, the equivalents of the present invention are included in the present invention. It is possible to arbitrarily combine or omit respective components according to claims and description in a range in which at least a part of the above-described problems can be solved, or a range in which at least a part of the effects can be exhibited.
This application discloses, as one embodiment, a polishing unit that includes a polishing table, a top ring, a light emitting member, a slip-out detector, and an elimination mechanism. A polishing pad for polishing a substrate is attached to the polishing table. The top ring holds the substrate to press the substrate against the polishing pad. The light emitting member emits a light to a detection area on the polishing pad. The slip-out detector detects a slip out of the substrate from the top ring based on the light reflected from the detection area. The elimination mechanism eliminates a polishing liquid flowing into the detection area.
This application further discloses, as one embodiment, the polishing unit in which the slip-out detector detects the slip out of the substrate from the top ring based on a change of a color of the light reflected from the detection area.
This application further discloses, as one embodiment, the polishing unit in which the slip-out detector detects the slip out of the substrate from the top ring based on a change of an amount of the light reflected from the detection area in addition to the change of the color of the light reflected from the detection area.
This application further discloses, as one embodiment, the polishing unit in which the elimination mechanism includes a purge mechanism for spraying a fluid to the detection area to eliminate the polishing liquid flowing into the detection area.
This application further discloses, as one embodiment, the polishing unit in which the elimination mechanism includes a suction mechanism for suctioning the polishing liquid flowing into the detection area to eliminate the polishing liquid flowing into the detection area.
This application further discloses, as one embodiment, the polishing unit in which the light emitting member, the slip-out detector, and the elimination mechanism are disposed to each of a plurality of detection areas on the polishing pad.
This application further discloses, as one embodiment, the polishing unit in which the light emitting member, the slip-out detector, and the elimination mechanism are mounted to the top ring.
This application further discloses, as one embodiment, a substrate processing apparatus that includes any one of the above-described polishing units that polishes a substrate, a conveyance unit that conveys the substrate, and a drying unit that dries the substrate.
This application further discloses, as one embodiment, a polishing method that includes a polishing step of polishing a substrate by flowing a polishing liquid on a polishing pad that polishes the substrate, a detecting step of emitting a light to a detection area on the polishing pad and detecting a slip out of the substrate from the top ring based on the light reflected from the detection area, and an eliminating step of eliminating the polishing liquid flowing into the detection area.
This application further discloses, as one embodiment, the polishing method in which the detecting step includes detecting the slip out of the substrate from the top ring based on a difference between a reference color of a light reflected from the detection area of the polishing pad as a reference and a color of the light reflected from the detection area of the polishing pad during a polishing process.
This application further discloses, as one embodiment, the polishing method that further includes a step of counting a cumulative number of polishing processes of the substrate and a step of registering the reference color when the cumulative number of polishing processes exceeds a threshold value.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-233037 | Dec 2019 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5823853 | Bartels | Oct 1998 | A |
| 6293846 | Oguri | Sep 2001 | B1 |
| 6425801 | Takeishi et al. | Jul 2002 | B1 |
| 6461222 | Sato | Oct 2002 | B1 |
| 20050130562 | Nabeya | Jun 2005 | A1 |
| 20050221724 | Terada et al. | Oct 2005 | A1 |
| 20090036024 | Matsuzaki | Feb 2009 | A1 |
| 20090209175 | Saito | Aug 2009 | A1 |
| 20150117755 | Doughty | Apr 2015 | A1 |
| 20150231760 | Maruyama | Aug 2015 | A1 |
| 20170304986 | Ueno et al. | Oct 2017 | A1 |
| 20180297170 | Chen | Oct 2018 | A1 |
| 20210031331 | Trojan | Feb 2021 | A1 |
| Number | Date | Country |
|---|---|---|
| H11-10525 | Jan 1999 | JP |
| H11-345791 | Dec 1999 | JP |
| 3761673 | Mar 2006 | JP |
| 2006-128582 | May 2006 | JP |
| 2016-087713 | May 2016 | JP |
| 2006-009304 | Jan 2006 | WO |
| 2006-049269 | May 2006 | WO |
| Entry |
|---|
| Extended European Search Report dated May 27, 2021 issued in European Patent Application No. EP 2021 2570.4. |
| Number | Date | Country | |
|---|---|---|---|
| 20210187692 A1 | Jun 2021 | US |
