JP2020138264A - Polishing device, polishing method, and memory medium storing program - Google Patents

Abstract

To provide a device, a method, and a memory medium for improving precision of film thickness detection of a substrate.SOLUTION: The polishing device is assembled with a polishing table 30A for supporting a polishing pad having a polishing face, a top ring 31A for holding a substrate W and pushing the substrate to a polishing face 10a, a film thickness sensor 39 arranged in the polishing table, a position detector 101 for detecting a rotation position of the film thickness sensor while rotating the polishing table, and a control device for landing the top ring on the polishing face based on the detection result of the rotation position of the film thickness sensor with the position detector.SELECTED DRAWING: Figure 3

Description

The present invention relates to a polishing apparatus, a polishing method, and a storage medium containing a program for executing the polishing method.

In a polishing apparatus for polishing a substrate such as a semiconductor wafer, an in situ film thickness sensor may be used for the purpose of monitoring the progress of polishing during the polishing process. As the film thickness sensor, an eddy current sensor (Patent Documents 1 and 3), an optical sensor (Patent Document 2) and the like are used. As shown in Patent Documents 1 and 2, such a film thickness sensor is provided so as to rotate together with the turntable, and detects the film thickness of the substrate when the substrate to be polished passes through the film thickness sensor.

JP-A-2010-253627 Japanese Unexamined Patent Publication No. 2015-20242 Japanese Unexamined Patent Publication No. 2011-23579

In the polishing apparatus, the top ring holding the substrate is landed (touchdown) and brought into contact with the polishing surface of the rotating turntable, and the substrate is polished by the relative rotation between the substrate and the polishing surface. The timing of landing the top ring on the turntable is independent of the position of the film thickness sensor on the turntable. Therefore, for each substrate, the measurement by the film thickness sensor is started after a different time after the top ring lands, that is, a different time after the start of polishing the substrate, and the measurement start time is different between the substrates.

For example, there is a possibility that the polishing amount data of the substrate at the start of measurement by the film thickness sensor is significantly different between the case where the substrate lands immediately before the film thickness sensor and the case where the substrate lands immediately after the film thickness sensor. That is, when the substrate lands immediately before the film thickness sensor, the measurement is started from the polishing amount data of the substrate in a state where it is hardly polished, but when the substrate lands immediately after the film thickness sensor, the turntable The measurement is started from the polishing amount data of the substrate in the state of being polished for about one round of the rotation of. Due to the recent progress in thinning the substrate, this difference in the amount of polishing for about one round may not be overlooked.
An object of the present invention is to solve at least a part of the above-mentioned problems.

One aspect of the present invention includes a polishing table that supports a polishing pad having a polishing surface, a top ring that holds a substrate and presses the substrate against the polishing surface, and a film thickness sensor arranged in the polishing table. The top ring lands on the polished surface based on the position detection device that detects the rotation position of the film thickness sensor during the rotation of the polishing table and the detection result of the rotation position of the film thickness sensor by the position detection device. The present invention relates to a polishing device, comprising a control device for making the device.

One aspect of the present invention is a polishing method in which a substrate held by a top ring is pressed against a polishing surface of a polishing table for polishing, and a film thickness sensor fixed to the polishing table during rotation of the polishing table. The present invention relates to a method including detecting the rotation position of the top ring and landing the top ring on the polished surface based on the detection result of the rotation position of the film thickness sensor.

It is a figure which shows the polishing apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows typically the polishing unit. It is a top view which shows the polishing unit schematically. It is a flowchart of the touchdown process of the top ring. It is a figure which shows the structural example of the sensor for detecting the rotation position of a substrate. It is a flowchart of the touchdown process of the top ring.

(First Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, this polishing apparatus includes a load / unload unit 2, a polishing unit 3, and a cleaning unit 4. As shown in FIG. 1, the load / unload portion 2, the polishing portion 3, and the cleaning portion 4 are partitioned by partition walls 1a and 1b inside a substantially rectangular housing 1. Further, a control device 5 for controlling the operation of each part of the polishing device is provided inside or outside the housing 1. The member to be polished can be any substrate such as a semiconductor wafer, a printed circuit board, a liquid crystal substrate, and a MEMS. In the following description, the member to be polished is simply referred to as a substrate or a wafer.

The load / unload unit 2 includes a front load unit 20 on which a wafer cassette for stocking one or a plurality of wafers is placed. A traveling mechanism 21 is laid along the front load portion 20 in the load / unload portion 2, and two transfer robots (2 transfer robots) that can move along the arrangement direction of the wafer cassettes on the traveling mechanism 21. Loader) 22 is installed. The transfer robot 22 can access the wafer cassette mounted on the front load unit 20 by moving on the traveling mechanism 21. Further, in this example, an in-line film thickness measuring device 80 is provided adjacent to the transfer robot 22 (described later). The wafer (substrate) as a member to be polished is conveyed to the in-line film thickness measuring device 80 by the transfer robot 22 before and / or after polishing, and the film thickness of the wafer is measured here.

The polishing unit 3 is a region where the wafer is polished, and includes a first polishing unit 3A, a second polishing unit 3B, a third polishing unit 3C, and a fourth polishing unit 3D. As shown in FIG. 1, the first polishing unit 3A holds the first polishing table 30A to which the polishing pad 10 having a polishing surface is attached, and presses the wafer against the polishing pad 10 on the polishing table 30A. The first top ring 31A for polishing while polishing, the first polishing liquid supply mechanism 32A for supplying a polishing liquid (for example, slurry) or dressing liquid (for example, pure water) to the polishing pad 10, and polishing of the polishing pad 10. The first dresser 33A for dressing the surface and the first atomizer 34A that atomizes a mixed fluid of liquid (for example, pure water) and gas (for example, nitrogen gas) or liquid (for example, pure water) and injects it onto the polished surface. And have.

Similarly, the second polishing unit 3B includes a second polishing table 30B to which the polishing pad 10 is attached, a second top ring 31B, a second polishing liquid supply mechanism 32B, a second dresser 33B, and a second atomizer 34B. And have. Similarly, the third polishing unit 3C includes a third polishing table 30C to which the polishing pad 10 is attached, a third top ring 31C, a third polishing liquid supply mechanism 32C, a third dresser 33C, and a third atomizer 34C. And have. Similarly, the fourth polishing unit 3D includes a fourth polishing table 30D to which the polishing pad 10 is attached, a fourth top ring 31D, a fourth polishing liquid supply mechanism 32D, a fourth dresser 33D, and a fourth atomizer 34D. And have.

Polishing of the wafer W is performed as follows. The top ring 31A and the polishing table 30A are rotated (see FIG. 2), and the polishing liquid (slurry) is supplied onto the polishing pad 10 from the polishing liquid supply mechanism 32A. In this state, the top ring 31A holding the wafer W on the lower surface makes the wafer W land (contact) with the polishing surface 10a of the polishing pad 10 and presses it. The surface of the wafer W is polished by the mechanical action of the abrasive grains contained in the polishing liquid and the chemical action of the polishing liquid. After the polishing is completed, the dresser 33A is used to dress (condition) the polished surface 10a, and a high-pressure fluid is supplied from the atomizer 34A to the polished surface 10a to remove polishing debris and abrasive grains remaining on the polishing surface 10a. Will be done.

In FIG. 1, the first linear transporter 6 is arranged adjacent to the first polishing unit 3A and the second polishing unit 3B. The first linear transporter 6 is a mechanism for transporting wafers between four transport positions (first transport position TP1, second transport position TP2, third transport position TP3, and fourth transport position TP4). Further, a second linear transporter 7 is arranged adjacent to the third polishing unit 3C and the fourth polishing unit 3D. The second linear transporter 7 is a mechanism for transporting wafers between three transport positions (fifth transport position TP5, sixth transport position TP6, and seventh transport position TP7).

The wafer is conveyed to the polishing units 3A and 3B by the first linear transporter 6. The top ring 31A of the first polishing unit 3A moves between the upper position of the polishing table 30A and the second transport position TP2 by its swing operation. Therefore, the transfer of the wafer to the top ring 31A is performed at the second transfer position TP2. Similarly, the top ring 31B of the second polishing unit 3B moves between the upper position of the polishing table 30B and the third transfer position TP3, and the wafer is transferred to the top ring 31B at the third transfer position TP3. The top ring 31C of the third polishing unit 3C moves between the upper position of the polishing table 30C and the sixth transfer position TP6, and the wafer is transferred to the top ring 31C at the sixth transfer position TP6. The top ring 31D of the 4th polishing unit 3D moves between the upper position of the polishing table 30D and the 7th transfer position TP7, and the wafer is transferred to the top ring 31D at the 7th transfer position TP7.

A lifter 11 for receiving the wafer from the transfer robot 22 is arranged adjacent to the first transfer position TP1. The wafer is passed from the transfer robot 22 to the first linear transporter 6 via the lifter 11. A shutter (not shown) is provided on the partition wall 1a so as to be located between the lifter 11 and the transfer robot 22 so that the shutter is opened when the wafer is transferred and the wafer is transferred from the transfer robot 22 to the lifter 11. It has become.

A swing transporter 12 is arranged between the first linear transporter 6, the second linear transporter 7, and the cleaning unit 4. Wafer transfer from the first linear transporter 6 to the second linear transporter 7 is performed by the swing transporter 12. The wafer is transported to the third polishing unit 3C and / or the fourth polishing unit 3D by the second linear transporter 7.

On the side of the swing transporter 12, a temporary wafer 72 placed on a frame (not shown) is arranged. The temporary storage table 72 is arranged adjacent to the first linear transporter 6, and is located between the first linear transporter 6 and the cleaning unit 4. The swing transporter 12 moves between the fourth transport position TP4, the fifth transport position TP5, and the temporary storage table 72. The wafer placed on the temporary stand 72 is conveyed to the cleaning unit 4 by the first transfer robot 77 of the cleaning unit 4. In the above-described embodiment, when the wafer is transferred between the polishing units 3A-3D, the wafer is separated from the top ring and transported to another polishing unit via the linear transporters 6 and 7. The wafer transfer mechanism between the polishing units is not limited to the above example, and the wafer may be transferred by, for example, the top ring moving directly to another polishing unit while holding the wafer.

The cleaning unit 4 includes a primary cleaning machine 73 and a secondary cleaning machine 74 for cleaning the polished wafer with a cleaning liquid, and a dryer 75 for drying the cleaned wafer. A first transfer robot 77 is arranged between the primary washing machine 73 and the secondary washing machine 74. The first transfer robot 77 operates so as to transfer the wafer from the temporary stand 72 to the primary cleaning machine 73, and further transfer the wafer from the primary cleaning machine 73 to the secondary cleaning machine 74. A second transfer robot 78 is arranged between the secondary washer 74 and the dryer 75. The second transfer robot 78 operates so as to transfer the wafer from the secondary washer 74 to the dryer 75.

The dried wafer is taken out from the dryer 75 by the transfer robot 22 and returned to the wafer cassette. In this way, a series of processes including polishing, cleaning, drying, and film thickness measurement are performed on the wafer.

The control device 5 controls the wafer processing operation by controlling the operation of each part of the polishing device described above. The control device 5 has a memory 5A that stores various setting data and various programs, and a CPU 5B that executes a memory program. The storage medium constituting the memory can include a volatile storage medium and / or a non-volatile storage medium. The storage medium may include, for example, one or more of any storage media such as ROM, RAM, hard disk, CD-ROM, DVD-ROM, flexible disk and the like. The programs stored in the memory are, for example, a program for controlling the transfer of each transfer robot, a program for controlling the polishing process of each polishing unit, a program for controlling each process of the cleaning machine and the dryer of the cleaning unit, and a film thickness measuring device. Includes a program that controls the processing of. Further, the control device 5 is configured to be able to communicate with a higher-level controller (not shown) that controls the polishing device and other related devices in an integrated manner, and can exchange data with the database of the higher-level controller.

FIG. 2 is a perspective view schematically showing the first polishing unit 31A. In the figure, the dresser 33A and the atomizer 34A are omitted. The first polishing unit 3A, the second polishing unit 3B, the third polishing unit 3C, and the fourth polishing unit 3D have the same configurations as each other. Therefore, refer to FIG. 2 for the first polishing unit 31A below. I will explain.

The polishing table 30A is connected to a table motor 19 arranged below the table shaft 30a via a table shaft 30a, and the table motor 19 rotates the polishing table 30A in the direction indicated by the arrow. A polishing surface 10a for polishing the wafer W is provided on the upper surface of the polishing table 30A. In this example, the polishing pad 10 is attached to the upper surface of the polishing table 30A, and the upper surface of the polishing pad 10 constitutes the polishing surface 10a. In addition, instead of the polishing pad, a polishing surface 10a made of a grindstone or the like may be provided on the upper surface of the polishing table 30A.

The top ring 31A is connected to the lower end of the top ring shaft 16 supported by the arm 35A. The top ring 31A is configured so that the wafer W can be held on the lower surface thereof by vacuum suction. The top ring shaft 16 is moved up and down by a vertical movement mechanism 23 provided inside or outside the arm 35A. As the vertical movement mechanism 23, any mechanism such as a ball screw, a rotation linear motion conversion mechanism such as a rack and pinion, and a cylinder driven by a fluid may be adopted. Further, the top ring shaft 16 is connected to the top ring motor 18 via a connecting means 17 such as a belt and is rotated. The rotation of the top ring shaft 16 causes the top ring 31A to rotate in the direction indicated by the arrow. Further, the arm 35A is connected to the arm shaft 36A and is rotated around the arm shaft 36A by the arm motor 37A. By the rotation of the arm 35A
The top ring 31A moves between the upper position of the polishing table 30A and the outer position of the polishing table 30A.

The first polishing unit 31A includes a film thickness measuring device 39 as an in situ film thickness measuring device for monitoring the film thickness of the wafer W. The film thickness measuring device 39 is arranged inside the polishing table 30A and is fixed at a position of a predetermined rotation angle of the polishing table 30A. The film thickness measuring device 39 has a sensor head that rotates integrally with the polishing table 30A and moves on the locus A with the rotation of the polishing table 30A. The film thickness measuring device 39 acquires a film thickness signal regarding the wafer W when passing below the wafer W held by the top ring 31A.

The film thickness measuring device 39 includes an arbitrary film thickness measuring device such as an optical film thickness sensor and a magnetic film thickness sensor. In the optical film thickness sensor, the surface of the wafer W is irradiated with light, the reflected light from the wafer W is received, and the film thickness of the wafer W is measured based on the intensity of the received reflected light. For example, it is possible to create a database in which the relationship between the intensity of the reflected light and the film thickness is measured in advance, and to obtain the film thickness corresponding to the intensity of the received reflected light from the database. When the optical film thickness sensor is a spectral film thickness sensor, the spectrum obtained by decomposing the reflected light received from the wafer for each wavelength is measured, and the film thickness of the wafer W is determined based on the measured spectrum. Measure (see, for example, Patent Document 2). In this case, for example, a database in which the relationship between the spectrum of the reflected light and the film thickness is measured in advance can be created, and the film thickness corresponding to the measured spectrum of the reflected light can be obtained from the database. As the magnetic film thickness sensor, there is an eddy current type film thickness sensor (see, for example, Patent Document 3). In the eddy current type film thickness sensor, the magnetic field lines generated from the exciting coil connected to the AC signal source are passed through the conductive layer on the wafer surface, and the eddy current is generated in the conductive layer. The thickness of the conductive layer is detected by measuring the magnetic flux generated by this eddy current in the direction opposite to the initial magnetic flux with the detection coil. The eddy current type film thickness sensor is a frequency type that detects the film thickness by detecting the change in the oscillation frequency of the AC signal source due to the eddy current, and the impedance change seen from the AC signal source due to the eddy current. Any impedance type that detects the film thickness may be used.

Further, the first polishing unit 31A includes a rotation position detecting device 101 (see FIG. 3) for detecting a position (rotation position, rotation angle) in the rotation direction of the polishing table 30A.

FIG. 3 is a plan view schematically showing the polishing unit. The rotation position detection device 101 has a proximity sensor 102 and a sensor target 103 as proximity sensor units. In the example of the figure, the proximity sensor 102 and the sensor target 103 are installed outside the polishing table 300A (rotating system) and the polishing table 30A (stationary system), respectively. However, the reverse arrangement may be used. That is, the proximity sensor 102 may be installed outside the polishing table 30A (stationary system), and the sensor target 103 may be installed on the polishing table 300A (rotating system). In the example of the figure, the proximity sensor 102 is fixed to, for example, the outer side surface of the polishing table 300A, and is fixed at a position (height) that passes through a position facing the sensor target 103 as the polishing table 300A rotates. ing. Further, in the example of the figure, the proximity sensor 102 is fixed in the same phase (position in the rotation direction) as the film thickness measuring device 39 on the polishing table 30A. In other words, the proximity sensor 102 is arranged on a radius passing through the center OT of the polishing table 30A and the film thickness measuring device 39. However, if the positional relationship between the proximity sensor 102 and the film thickness measuring device 39 is known, the rotational position of the film thickness measuring device 39 can be calculated from the detection result of the proximity sensor 102, so that the position of the proximity sensor 102 is the film thickness. It may be arranged in a phase different from that of the measuring device 39.

As shown in FIG. 3, the line connecting the center of the wafer W at the position where the top ring 31A lands on the polishing surface and the center OT of the polishing table 30A is defined as the x-axis, and the rotation angle clockwise from the x-axis around the center OT. Let θ be. At this time, the top ring 31A lands (contacts) with the polished surface 10a at the position of θ = 0. Further, the rotation position (rotation angle) of the film thickness measuring device 39 and the proximity sensor 102 that rotate together with the polishing table 30A is set to θ1. Further, it is assumed that the sensor target 103 is fixed outside the polishing table 30A at a rotation position of θ = α (constant). In this configuration, when the proximity sensor 102 detects the sensor target 103 as the polishing table 30A rotates, it can be detected that the rotation position of the film thickness measuring device 39 has reached θ1 = α. In other words, when the proximity sensor 102 detects the sensor target 103, the film thickness measuring device 39 reaches the rotation position before the position where the wafer W is landed (θ = 0) by θ = 360 degrees −α. It is possible to detect what has been done. Therefore, by landing the wafer W on the polishing surface 10a by the top ring 31A in synchronization with the timing when the proximity sensor 102 detects the sensor target 103, a certain time after the landing of the wafer W (a certain polishing process). Later), the measurement of the thickness of the wafer W by the film thickness measuring device 39 can be started.

The rotation position of the proximity sensor 102 for detecting the sensor target 103 is aligned with or brought closer to the rotation position of the intersection W1 between the outer peripheral edge of the wafer W and the locus A of the film thickness measuring device 39. The film thickness measurement of the wafer W by the film thickness measuring device 39 can be started substantially at the same time as the landing or the start of polishing. Further, even when the rotation position where the proximity sensor 102 detects the sensor target 103 is far from the rotation position of the intersection W1, the film thickness measuring device 39 is always after a certain time from the landing of the wafer W or the start of polishing. The film thickness measurement of the wafer W can be started.

FIG. 4 is a flowchart of the touchdown process of the top ring. After rotating the top ring 31A for holding the wafer W and the polishing table 30A to supply the polishing liquid (slurry) onto the polishing pad 10 from the polishing liquid supply mechanism 32A (see FIGS. 2 and 3), FIG. Processing is started.

In step S11, it is determined whether or not the film thickness measuring device 39 has reached the predetermined rotation position θ1 = α based on whether or not the proximity sensor 102 has detected the sensor target 103. This process is repeated until the film thickness measuring device 39 reaches a predetermined rotation position θ1 = α. When the film thickness measuring device 39 reaches the predetermined rotation position θ1 = α, the process proceeds to step S12. In one example, the control device 5 determines whether or not the film thickness measuring device 39 has reached a predetermined rotation position θ1 = α based on the output signal from the rotation position detection device 101.

In step S12, an instruction to start measurement is output to the film thickness measuring device 39. In one example, when the control device 5 determines that the film thickness measuring device 39 has reached the predetermined rotation position θ1 = α based on the output signal from the rotation position detecting device 101, the film thickness measuring device 39 starts measuring. Output instructions.

In step S13, the top ring 31A is landed on the polished surface 10a. In one example, the control device 5 drives the vertical movement mechanism 23 of the top ring shaft 16 to lower and land the top ring 31A toward the polished surface 10a. The top ring 31A may be landed at the same time when the film thickness measuring device 39 reaches the rotation position of θ1 = α, or may be landed after a predetermined time from the arrival.

According to this embodiment, the wafer held by the top ring 31A is landed on the polishing surface based on the detection result of the rotation position of the film thickness measuring device 39, so that after a certain time at the start of polishing the wafer (polishing). The film thickness measurement can be started at almost the same time as the start), and the film thickness measurement start time can be made uniform among a plurality of wafers with respect to the polishing start time. Since the film thickness of each wafer can be measured under uniform conditions, it becomes easy to compare the film thickness data between the wafers.

In the configuration not adopting the above embodiment, for example, the wafer measured by the film thickness sensor at the start of measurement is the case where the wafer lands immediately before the film thickness sensor and the case where the wafer lands immediately after the film thickness sensor. Polishing amount data may differ significantly. That is, when the wafer lands immediately before the film thickness sensor, the measurement is started from the polishing amount data of the wafer in a state where it is hardly polished, but when the wafer lands immediately after the film thickness sensor, the turntable The measurement is started from the polishing amount data of the substrate in the state of being polished for about one round of the rotation of. In this case, at the start of film thickness measurement, there is a difference in the amount of polishing for about one round. On the other hand, according to the above embodiment, the film thickness measurement can be started substantially at the same time as the start of polishing the wafer or after a certain period of time, so that the film thickness measurement of each wafer can be performed under uniform conditions. It becomes easy to compare the film thickness data between them.

Further, the positions on the polishing table 30A at which polishing and film thickness measurement are started can be made the same among the plurality of wafers. Even if the state of the polished surface 10a is not uniform depending on the location, the polishing process and the film thickness measurement of each wafer can be started under more uniform conditions. The film thickness of each wafer can be measured under more uniform conditions, and the comparison of film thickness data between wafers becomes easier.

In the above, the proximity sensor unit is adopted as the rotation position detection device 101, but an encoder (not shown) that detects the rotation position of the polishing table 30A may be used as the rotation position detection device 101. By comparing the rotation position detected by the encoder with the predetermined rotation position in the control device 5, it is possible to detect that the film thickness measuring device 39 has reached the predetermined position. The encoder can be provided on the rotating shaft of the table motor 19, the power transmission mechanism, the polishing table 30, and the like.

(Second Embodiment)
In the above embodiment, the proximity sensor or encoder is provided to detect the rotation position (rotation angle) of the polishing table 30A, but the rotation of the polishing table 30A is performed by acquiring the phase of the table motor 19 that rotates the polishing table 30A. The rotation position (rotation angle) of the film thickness measuring device 39 fixed at the position or the predetermined position of the polishing table 30A may be detected. The phase of the table motor 19 can be obtained, for example, from the waveform of the current and / or voltage driving the table motor 19. In this case, in step S11 of FIG. 4, the control device 5 acquires the phase from the table motor 19 and determines the rotation position θ1 of the film thickness measuring device 39 based on the acquired phase, and the film thickness measuring device By comparing the rotation position θ1 of the 39 with the predetermined rotation position θ = α, it is possible to detect that the rotation position θ1 of the film thickness measuring device 39 has become α.

According to this embodiment, the rotation position θ1 of the film thickness measuring device 39 can be detected without providing a separate sensor such as a proximity sensor or an encoder.

(Third Embodiment)
FIG. 5 is a diagram showing a configuration example of a sensor for detecting the rotational position of the substrate. In the above embodiment, the rotation position (rotation angle) of the polishing table 30A or the film thickness measuring device 39 fixed to the polishing table 30A is detected, but in addition to this, it is held by the top ring 31A or the top ring 31A. The rotation position (rotation angle) of the wafer W may be detected. For example, as shown in FIG. 5, on the bottom surface of the top ring 31A, a plurality of sensors 38A are provided at positions facing the wafer W along the circumferential direction of the wafer W, and the wafer W with respect to the top ring 31A is provided by the plurality of sensors 38A. It is configured to detect the orientation of the orientation flat or notch (rotation position, rotation angle). The sensor 38A may be either an optical sensor or a magnetic sensor. In one example, each sensor 38A can use a reflective optical sensor including a light emitting unit and a light receiving unit. Light is output from the light emitting part of each sensor toward the wafer W, the reflected light from the wafer W is received by the light receiving part, and the portion having a different intensity of the reflected light is detected to rotate the orientation flat or notch of the wafer. The position can be detected. Further, by detecting the phase of the top ring motor 18 that rotates the top ring 31A and / or the arm motor 37A that rotates the arm 35A, the rotation angle of the top ring 31A with respect to the x-axis (FIG. 3) which is a stationary system. That is, the rotation position of each sensor 38A is specified. The phase of each motor can be obtained, for example, from the waveform of the current and / or voltage driving each motor. Further, an encoder may be provided on the rotation shaft of each motor, a power transmission mechanism, or the like to detect the phase (rotation angle) of each motor.

After the top ring 31A receives the wafer W before polishing, the sensor 38A detects the position of the orientation flat or notch of the wafer W, and the rotation position of the wafer W with respect to the top ring 31A before the top ring 31A is rotated. Identify. Then, after rotating the arm 35A and the top ring 31A, the phase of the top ring motor 18 and / or the arm motor 37A is acquired to obtain the detection result of the sensor 38A and the phase of the top ring motor 18 and / or the arm motor 37A. From, the rotation position of the orientation flat / or notch of the wafer W with respect to the x-axis (FIG. 3) is detected. At the end of rotation of the top ring 31A, the rotation position of each sensor 38A is stored.

FIG. 6 is a flowchart of the touchdown process of the top ring.
In step S21, after the top ring 31A receives the wafer W before polishing, the rotation position of the wafer W with respect to the top ring 31A is detected by detecting the position of the orientation flat or notch of the wafer W by the sensor 38A on the bottom surface of the top ring 31A. To identify. After that, when the top ring 31A is swung by the rotation of the arm 35A and / or the rotation of the top ring 31A is started, the x-axis (FIG. 3) is based on the phase of the top ring motor 18 and / or the arm motor 37A. The rotation position of the top ring 31A with respect to is calculated. The rotation position θ2 of the wafer W with respect to the x-axis (FIG. 3) is detected based on the rotation position of the wafer W with respect to the top ring 31A and the rotation position of the top ring 31A with respect to the x-axis (FIG. 3). Further, the rotation of the polishing table 30A is started before, after, or in the middle of step S21. In one example, these processes are performed by the control device 5.

In step S22, while the polishing table 30A and the top ring 31A are rotating, the film thickness measuring device 39 is in a predetermined rotation position (θ1 = α), and the wafer W is in a predetermined rotation position (for example, θ2 = 0). Judge whether or not. The process of step S22 is repeated until the condition that the film thickness measuring device 39 reaches the predetermined rotation position (θ1 = α) and the wafer W has the predetermined rotation position θ2 = β (for example, β = 0) is satisfied. When the condition is satisfied, the process proceeds to step S23. In one example, these processes are performed by the control device 5.

In step S23, an instruction to start measurement is output to the film thickness measuring device 39. In one example, the control device 5 determines that the condition that the film thickness measuring device 39 is at a predetermined rotation position (θ1 = α) and the wafer W is at a predetermined rotation position (for example, θ2 = 0) is satisfied. At this time, an instruction to start measurement is output to the film thickness measuring device 39.

In step S24, the top ring 31A is landed on the polished surface 10a. In one example, the control device 5 drives the vertical movement mechanism 23 of the top ring shaft 16 to lower the top ring 31A toward the polished surface 10a.

The top ring 31A may be landed at the same time when the film thickness measuring device 39 reaches the rotation position of θ1 = α. Further, the top ring 31A may be landed after a predetermined time after the film thickness measuring device 39 reaches the rotation position of θ1 = α. In this case, the value of the predetermined rotation position β at the time of landing of the wafer W is determined in consideration of the elapsed time from the rotation position of the film thickness measuring device 39 when θ1 = α to the landing of the wafer W. May be good.

According to this embodiment, in addition to the action and effect described in the above embodiment, the rotation position (orientation) of the wafer W at the time of landing the wafer W on the polished surface 10a can always be constant. In other words, the position where the film thickness measuring device first passes through the substrate and the film thickness measurement is started can be made constant. This makes it possible to compare polishing data between a plurality of wafers under more uniform conditions.

At least the following technical ideas are grasped from the above embodiment.
According to the first embodiment, a polishing table that supports a polishing pad having a polishing surface, a top ring that holds the substrate and presses the substrate against the polishing surface, and a film thickness sensor arranged in the polishing table. The top ring lands on the polished surface based on the position detection device that detects the rotation position of the film thickness sensor during the rotation of the polishing table and the detection result of the rotation position of the film thickness sensor by the position detection device. A polishing device is provided, comprising a control device for the operation.

According to this form, the wafer held by the top ring is landed on the polished surface based on the detection result of the rotation position by the film thickness sensor, so that after a certain time at the start of polishing the wafer (almost at the same time as the start of polishing). The film thickness measurement can be started at (including the case of), and the film thickness measurement start time can be made uniform among a plurality of wafers with respect to the polishing start time. Since the film thickness measurement can be started substantially at the same time as the start of polishing the wafer or after a certain period of time, the film thickness measurement of each wafer can be performed under uniform conditions. Further, since the film thickness of each wafer can be measured under uniform conditions, it becomes easy to compare the film thickness data between the wafers. In addition, the positions on the polishing table at which polishing and film thickness measurement are started can be made the same among the plurality of wafers. As a result, even if the state of the polished surface is not uniform depending on the location, the polishing process and the film thickness measurement of each wafer can be started under more uniform conditions. The film thickness of each wafer can be measured under more uniform conditions, and the comparison of film thickness data between wafers becomes easier.

According to the second aspect, in the polishing apparatus of the first embodiment, the position detecting apparatus has a proximity sensor that detects that the film thickness sensor has reached a predetermined rotation position. According to this form, the position of the film thickness sensor can be detected easily and with sufficient accuracy by using the proximity sensor.

According to the third aspect, in the polishing apparatus of the first embodiment, the position detecting apparatus has an encoder. According to this form, the position of the film thickness sensor can be detected easily and with sufficient accuracy by using the encoder.

According to the fourth aspect, the polishing apparatus of the first embodiment further includes a motor for rotating the polishing table, and the position detecting apparatus detects the position of the film thickness sensor by acquiring the phase of the motor. To do. According to this form, the position of the film thickness sensor can be detected easily and with sufficient accuracy by acquiring the phase of the motor. When calculating the phase from the current and / or voltage that drives the motor, the position of the film thickness sensor can be detected without separately providing a sensor for detecting the position of the film thickness sensor.

According to the fifth aspect, the polishing apparatus of the first embodiment further includes a rotation swing mechanism for rotating the top ring, and the top ring has a rotation angle detecting device for detecting the rotation position of the substrate. The top ring is landed on the polished surface based on the detection results of the position detection device and the rotation angle detection device. According to this form, the start time of the film thickness measurement with respect to the landing of the top ring is controlled, and the orientation of the substrate at the start of the film thickness measurement, that is, the film thickness measuring device first passes through the substrate to start the film thickness measurement. It is possible to manage the position to be performed. This makes it possible to compare polishing data between a plurality of wafers under more uniform conditions.

According to the sixth aspect, in the polishing apparatus of the fifth aspect, the top ring is landed on the polishing surface with the substrate facing a predetermined direction based on the detection result of the rotation angle detecting apparatus. According to this form, the substrate can be landed on the polished surface of the polishing table in a constant direction, and the film thickness measurement of the substrate can be started at the same time as the landing or after a certain period of time. As a result, the position of the substrate on which the film thickness measurement is started in the substrate is also constant among the plurality of substrates. Therefore, the conditions for measuring the film thickness are more uniform among the plurality of substrates, and the accuracy of comparing the film thickness data is further improved.

According to the seventh aspect, in the polishing apparatus of the fifth or sixth embodiment, the rotation angle detecting apparatus detects the position of the orientation flat or the notch of the substrate. According to this form, the orientation of the substrate can be detected with sufficient accuracy by detecting the position of the orientation flat or the notch of the substrate.

According to the eighth aspect, in any of the fifth to seventh forms of the polishing apparatus, the rotational swing mechanism has one or a plurality of motors, and the rotational angle detecting apparatus detects the phase of the motors. Thereby, the rotation position of the substrate is detected. According to this form, the rotational position of the substrate can be detected easily and with sufficient accuracy based on the phase of the motor that rotates and / or swings the top ring.

According to the ninth aspect, in the polishing apparatus of the eighth aspect, the rotation angle detecting apparatus has a plurality of sensors provided on the top ring along the circumferential direction. According to this form, the rotation position (orientation) of the substrate with respect to the top ring can be determined easily and with sufficient accuracy.

According to the tenth aspect, in a polishing method in which a substrate held by a top ring is pressed against a polishing surface on a polishing table to polish, the film thickness fixed to the polishing table during rotation of the polishing table. A method is provided that includes detecting the rotational position of the sensor and landing the top ring on the polished surface based on the detection result of the rotational position of the film thickness sensor.

According to the eleventh embodiment, a non-volatile program that stores a program that operates a computer to execute a control method of a polishing device that presses a substrate held by a top ring against a polishing surface on a polishing table to polish. The top ring is a recording medium, and the top ring is detected based on the detection result of the rotation position of the film thickness sensor fixed to the polishing table during the rotation of the polishing table and the detection result of the rotation position of the film thickness sensor. Non-volatile recording media for storing programs are provided, including landing on the polished surface.

Although the embodiments of the present invention have been described above based on some examples, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and do not limit the present invention. .. The present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes an equivalent thereof. In addition, any combination or omission of the scope of claims and the components described in the specification is possible within the range in which at least a part of the above-mentioned problems can be solved or at least a part of the effect is exhibited. Is.

1 Housing 2 Load / unload part 3 Polishing part 3A, 3B, 3C, 3D Polishing unit 4 Cleaning part 5 Operation control part 6 1st linear transporter 7 2nd linear transporter 10 Polishing pad 11 Lifter 12 Swing transporter 16 Top Ring shaft 17 Connecting means 18 Top ring motor 19 Table motor 20 Front load section 21 Travel mechanism 22 Conveying robot 30A, 30B, 30C, 30D Polishing table 31A, 31B, 31C, 31D Top ring 32A, 32B, 32C, 32D Polishing liquid supply Mechanism 33A, 33B, 33C, 33D Dresser 34A, 34B, 34C, 34D Atomizer 35A Arm 36A Arm shaft 37A Arm motor 38A Sensor 39 Thickness measuring device 72 Temporary stand 73 Primary cleaning machine 74 Secondary cleaning machine 75 Dryer 77 1 transfer robot 78 2nd transfer robot 80 In-line film thickness measuring instrument

Claims (11)

A polishing table that supports a polishing pad with a polishing surface,
A top ring that holds the substrate and presses the substrate against the polished surface,
The film thickness sensor arranged in the polishing table and
A position detection device that detects the rotation position of the film thickness sensor while the polishing table is rotating, and
A control device for landing the top ring on the polished surface based on the detection result of the rotational position of the film thickness sensor by the position detecting device.
Polishing equipment. In the polishing apparatus according to claim 1,
The position detecting device is a polishing device having a proximity sensor that detects that the film thickness sensor has reached a predetermined rotation position. In the polishing apparatus according to claim 1,
The position detecting device is a polishing device having an encoder. In the polishing apparatus according to claim 1,
Further equipped with a motor for rotating the polishing table,
The position detecting device is a polishing device that detects the position of the film thickness sensor by acquiring the phase of the motor. In the polishing apparatus according to claim 1,
A rotary swing mechanism for rotating and / or swinging the top ring is further provided.
The top ring has a rotation angle detecting device for detecting the rotation position of the substrate.
Based on the detection results of the position detection device and the rotation angle detection device, the top ring is landed on the polished surface.
Polishing equipment. In the polishing apparatus according to claim 5,
A polishing device that lands the top ring on the polishing surface with the substrate facing a predetermined direction based on the detection result of the rotation angle detection device. In the polishing apparatus according to claim 5 or 6,
The rotation angle detecting device is a polishing device that detects the position of an orientation flat or a notch on the substrate. In the polishing apparatus according to any one of claims 5 to 7.
The rotary swing mechanism has one or more motors.
The rotation angle detection device is a polishing device that detects the rotation position of the substrate by detecting the phase of the motor. In the polishing apparatus according to claim 8,
The rotation angle detecting device is a polishing device having a plurality of sensors provided on the top ring along the circumferential direction. In a polishing method in which a substrate held by a top ring is pressed against a polishing surface on a polishing table for polishing.
To detect the rotation position of the film thickness sensor fixed to the polishing table during the rotation of the polishing table.
Landing the top ring on the polished surface based on the detection result of the rotation position of the film thickness sensor.
Including methods. A non-volatile recording medium that stores a program that operates a computer to execute a control method of a polishing device that presses a substrate held by a top ring against a polishing surface on a polishing table to polish.
To detect the rotation position of the film thickness sensor fixed to the polishing table during the rotation of the polishing table.
Landing the top ring on the polished surface based on the detection result of the rotation position of the film thickness sensor.
A non-volatile recording medium for storing programs, including.

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