KR20240102835A - Polishing apparatus and polishing method - Google Patents

Abstract

Even if the number of sensor heads increases, the increase in the size of the polishing device provides a polishing device that is improved over the conventional one.
The polishing device 110 for polishing the substrate W has a polishing table for holding a polishing pad and a polishing head for pressing the surface of the substrate W against the polishing pad. The plurality of first optical heads 131 to 134 move across the substrate W and detect signals related to the film thickness of the substrate W. One spectrometer 14 receives and processes signals output from at least two first sensor heads among the plurality of first sensor heads 131 to 134. The optical switch 40 selectively connects the sensor heads 131 to 134 to the spectroscope 14. The processing unit 15 uses an optical switch 40 to switch the connection with the spectroscope 14 from one sensor head to the other sensor head at the timing when the plurality of sensor heads 131 to 134 face the substrate at the same time. control.

Description

Polishing apparatus and polishing method {POLISHING APPARATUS AND POLISHING METHOD}

The present invention relates to a polishing device and a polishing method.

As a device for polishing the surface of a substrate such as a semiconductor wafer, a CMP (chemical mechanical polishing) device is widely known. This CMP device polishes the surface of the substrate by pressing the substrate against the polishing pad with a polishing head holding the wafer while supplying polishing liquid to a polishing pad on a rotating polishing table. A CMP device generally includes a film thickness measuring unit that measures the film thickness of the substrate or a signal equivalent to the film thickness, and determines the polishing load on the substrate based on the measured value of the film thickness obtained from the film thickness measuring unit. Control and further determine the polishing end point. As a film thickness measuring unit, an eddy current sensor or an optical sensor is generally used.

In a conventional CMP apparatus, the film thickness measuring unit is disposed inside the polishing table so as to face the substrate on the polishing pad. Therefore, each time the polishing table rotates, the film thickness measuring section moves across the substrate and measures the film thickness at a plurality of measurement points on the substrate. In a conventional CMP device, the film thickness measuring section is arranged to pass through the center of the substrate. This is to measure the film thickness at a plurality of measurement points distributed in the radial direction of the substrate.

In measuring the film thickness of a substrate being polished, it is known to provide a plurality of sensors for the purpose of acquiring highly accurate film thickness data on the entire surface including the center and peripheral portion of the substrate (Japanese Patent No. 6470365). With the miniaturization of devices, improvement in polishing precision is essential. To improve polishing precision, it is necessary to further improve measurement resolution. There is a need to increase the number of sensor heads to improve measurement resolution. If the number of signal processing units that receive and process signals output from the sensor heads increases according to the number of sensor heads, the polishing device becomes larger. This problem is more pronounced when using an optical sensor for film thickness measurement than when using an eddy current sensor. This is because the spectrometer, which is the signal processing unit of the optical sensor, is larger in size than the signal processing unit of the eddy current sensor. As the size increases, this becomes a problem if the installation area of the device is limited. Additionally, there is a problem that semiconductor productivity converted into production per unit area of the device decreases.

Japanese Patent No. 6470365

One form of the present invention was made to solve this problem, and its purpose is to provide a polishing device in which the amount of increase in the size of the polishing device is improved compared to the prior art even when the number of sensor heads increases.

In order to solve the above problem, in the first aspect, there is provided a polishing device for polishing a substrate, comprising: a polishing table for holding a polishing pad; a polishing head for pressing the surface of the substrate against the polishing pad; and a polishing head for pressing the surface of the substrate against the polishing pad, and A plurality of sensor heads that detect signals related to the film thickness of the substrate while moving, one spectrometer that receives and processes signals output by at least two of the plurality of sensor heads, and the at least two a switch for selectively connecting a sensor head to the spectrometer, and a control device, wherein the control device connects one sensor head to the spectrometer at a timing when the at least two sensor heads simultaneously face the substrate. The structure of the polishing device is adopted, wherein the switch is controlled to switch from one head to the other sensor head.

In this embodiment, at the timing when at least two sensor heads face the substrate at the same time, one spectrometer receives and processes signals output by at least two of the plurality of sensor heads, so the number of sensor heads is Even if it increases, the amount of increase in the size of the polishing device can provide a polishing device that is improved over the conventional one.

In a second aspect, the polishing table is rotatable around an axis of the polishing table, and the plurality of sensor heads are arranged in an area of the polishing table opposite to an area containing the center of the substrate. The structure of the polishing device described in the first form is adopted.

In the third aspect, a predetermined even number of the sensor heads among the plurality of sensor heads form a pair of two, and the two sensor heads constituting the pair are positioned on substantially opposite sides with respect to the axis. The polishing device according to the second aspect is characterized in that an even number of the sensor heads are arranged so that the line connecting the two sensor heads constituting the pair is at equal angular intervals around the axis. I'm doing it.

In the fourth aspect, for a predetermined four of the plurality of sensor heads, two of the sensor heads are positioned on substantially opposite sides with respect to the axis, and the other two sensor heads are positioned substantially opposite to each other with respect to the axis. are located on opposite sides of each other, and the angle formed by the line connecting the two sensor heads and the line connecting the other two sensor heads is greater than 0 degrees and less than 180 degrees. A structure called a polishing device is adopted.

In a fifth aspect, the polishing device includes a plurality of sensor heads, including a first sensor head that detects a signal regarding the film thickness of the substrate in an area including the center of the substrate, and a first sensor head that detects a signal related to the film thickness of the substrate along the peripheral edge of the substrate. A polishing device according to any one of the first to fourth aspects is employed, which includes a second sensor head that detects a signal about the film thickness of the substrate while moving.

In the sixth aspect, the plurality of first sensor heads is at least two, the plurality of second sensor heads is at least two, and the two first sensor heads are positioned on substantially opposite sides with respect to the axis. , the axis is located on a line segment connecting the two second sensor heads, and the angle formed by the line connecting the two first sensor heads and the line segment connecting the second sensor heads ranges from 0 degrees. The structure of the polishing device described in the fifth aspect, which is characterized by an angle of 180 degrees, is adopted.

In the seventh aspect, a predetermined number of the sensor heads among the plurality of sensor heads, and for the predetermined number of the sensor heads among the plurality of sensor heads, a predetermined number of other sensor heads and the polishing table. Adopting the structure of the polishing device according to any one of the first to fifth aspects, wherein one each of the predetermined number of different sensor heads is disposed on a line connecting the shaft centers, there is.

In the eighth aspect, for a predetermined two of the plurality of sensor heads and another predetermined four of the plurality of sensor heads, the predetermined two sensor heads are positioned on substantially opposite sides with respect to the axis. , the axis is located on a first line segment connecting two of the four sensor heads, and the axis is located on a second line segment connecting the other two sensor heads out of the four predetermined numbers. The polishing device according to any one of the first to fifth aspects is employed, and the angle formed by the first line segment and the second line segment is 0 degrees to 180 degrees.

In the ninth aspect, the four predetermined sensor heads are arranged symmetrically with respect to a third line connecting the two predetermined sensor heads, and the angle formed by the third line and the first line segment is The polishing device according to the eighth aspect is characterized in that the minimum angle is less than 90 degrees, and the minimum angle among the angles formed by the third line and the second line segment is less than 90 degrees.

In a tenth aspect, there is a polishing method for polishing a substrate, wherein a polishing table holds a polishing pad, a polishing head presses the surface of the substrate against the polishing pad, and a plurality of first sensor heads holds the polishing pad. While moving across, a signal regarding the film thickness of the substrate is detected in an area including the center of the substrate, one spectrometer receives and processes the signals output by the plurality of sensor heads, and a converter , the at least two sensor heads are selectively connected to the spectrometer, and the control device controls the connection with the spectroscope from one sensor head to the other when the at least two sensor heads simultaneously face the substrate. A structure called a polishing method is adopted, characterized in that the switch is controlled to switch to the first sensor head.

In an 11th aspect, there is a polishing device for polishing a substrate, comprising: a polishing table for holding a polishing pad; a polishing head for pressing a surface of a substrate against the polishing pad; and, while moving across the substrate, A plurality of sensors for detecting signals related to film thickness, one signal processing unit for receiving and processing signals output from at least two of the plurality of sensors, and selectively connecting the at least two sensors to the signal processing unit. a switcher and a control device, wherein the control device switches the connection with the signal processing unit from one sensor to the other sensor at a timing when the at least two sensors simultaneously face the substrate. A structure called a polishing device is adopted, which is characterized in that it controls the switching device.

In a twelfth aspect, there is a polishing device for polishing a substrate, comprising: a polishing table for holding a polishing pad; a polishing head for pressing a surface of a substrate against the polishing pad; and, while moving across the substrate, A plurality of sensor heads that detect signals related to film thickness, one spectrometer that receives and processes signals output by at least two sensor heads among the plurality of sensor heads, and a spectrometer that selectively uses the at least two sensor heads. a switch connected to and a control device, wherein the control device controls the spectrometer at a timing when one of the at least two sensor heads faces the substrate and the other does not face the substrate. A polishing device, wherein the switcher is controlled to initiate a switching process for switching a connection from the one sensor head to the other sensor head, or from the other sensor head to the one sensor head. The configuration is adopted.

In a 13th aspect, the other sensor head passes an end of the substrate when moving from a position not facing the substrate to a position facing the substrate, and the other sensor head passes through an end of the substrate when starting the switching process. The head adopts the structure of the polishing device according to the twelfth aspect, wherein the head is located near the end.

In the fourteenth aspect, before the one sensor head facing the substrate reaches the end of a trajectory passing under the substrate, the other sensor head that does not face the substrate is moved from the one sensor head. A polishing device according to the twelfth aspect is employed, which is characterized in that it starts the conversion process.

In the 15th aspect, after the one sensor head facing the substrate passes a starting point of a trajectory passing under the substrate, the other sensor head not facing the substrate is transferred from the one sensor head to the other sensor head. A polishing device according to the twelfth aspect is employed, which is characterized in that it starts the conversion process.

In a 16th aspect, the 12th aspect further includes a rocking device that swings the polishing head on the polishing pad during polishing, and controls the timing of starting the switching process according to the rocking position of the polishing head. The structure of the polishing device described in is adopted.

In a 17th aspect, there is a polishing device for polishing a substrate, comprising: a polishing table for holding a polishing pad; a polishing head for pressing a surface of a substrate against the polishing pad; and, while moving across the substrate, A plurality of sensor heads that detect signals related to film thickness, one spectrometer that receives and processes signals output by at least two sensor heads among the plurality of sensor heads, and a spectrometer that selectively uses the at least two sensor heads. and a switch connected to a control device, wherein the control device connects the spectrometer to the other sensor head at a timing when one sensor head of the at least two sensor heads does not face the substrate. A polishing device wherein the switcher is controlled to start a switching process for switching from the sensor head to the one sensor head, and the switching process is completed after the one sensor head passes a point in a trajectory passing under the substrate. configuration is being adopted.

In the 18th aspect, the polishing apparatus according to the 17th aspect is adopted, wherein the switching process is started at a timing when the other sensor head is not facing the substrate.

In a 19th aspect, a 17th aspect further comprises a rocking device that swings the polishing head on the polishing pad during polishing, and controls timing of starting the switching process according to a rocking position of the polishing head. The structure of the polishing device described in is adopted.

In a twentieth aspect, there is a polishing method for polishing a substrate, wherein a polishing table holds a polishing pad, a polishing head presses the surface of the substrate against the polishing pad, and a plurality of sensor heads horizontally align the substrate. While moving, a signal related to the film thickness of the substrate is detected, one spectrometer receives and processes signals output by at least two sensor heads among the plurality of sensor heads, and a converter receives and processes signals output from at least two sensor heads among the plurality of sensor heads. A head is selectively connected to the spectrometer, and the control device connects the at least two sensor heads to the spectroscope at a timing when one of the at least two sensor heads faces the substrate and the other does not face the substrate. , a polishing method characterized in that the switching device is controlled to initiate a switching process for switching from the one side to the other side, or from the other side to the one side.

In a 21st aspect, there is a polishing device for polishing a substrate, comprising: a polishing table for holding a polishing pad; a polishing head for pressing a surface of a substrate against the polishing pad; and, while moving across the substrate, A plurality of sensors for detecting signals related to film thickness, one signal processing unit for receiving and processing signals output from at least two of the plurality of sensors, and selectively connecting the at least two sensors to the signal processing unit. a switch and a control device, wherein the control device connects the signal processing unit at a timing when one of the at least two sensors faces the substrate and the other sensor does not face the substrate. The switching device is controlled to initiate a switching process for switching from the one side to the other side, or from the other side to the one side.

In the 22nd aspect, there is a polishing method for polishing a substrate, wherein a polishing table holds a polishing pad, a polishing head presses the surface of the substrate against the polishing pad, and a plurality of sensor heads horizontally horizontally align the substrate. While moving, a signal related to the film thickness of the substrate is detected, one spectrometer receives and processes signals output by at least two sensor heads among the plurality of sensor heads, and a converter receives and processes signals output from at least two sensor heads among the plurality of sensor heads. A head is selectively connected to the spectrometer, and the control device connects the head to the spectrometer at a timing when one of the at least two sensor heads does not face the substrate, from the other sensor head. Controlling the switch to start a switching process for switching to one sensor head, and controlling the switch to complete the switching process after the one sensor head passes a point in the trajectory of passing under the substrate. A structure called the characteristic polishing method is adopted.

In a 23rd aspect, there is a polishing device for polishing a substrate, comprising: a polishing table for holding a polishing pad; a polishing head for pressing a surface of a substrate against the polishing pad; and, while moving across the substrate, A plurality of sensors for detecting signals related to film thickness, one signal processing unit for receiving and processing signals output from at least two of the plurality of sensors, and selectively connecting the at least two sensors to the signal processing unit. and a control device, wherein the control device connects the signal processing unit at a timing when one of the at least two sensors does not face the substrate, and switches the sensor from the other sensor to the one sensor. Controlling the switching device to start a switching process for switching to a sensor, and controlling the switching device to complete the switching process after one of the sensors passes a point of a trajectory passing under the substrate. A structure called a polishing device is adopted.

Figure 1(a) is a schematic diagram for explaining the principle of determining the film thickness based on the spectrum of reflected light from the substrate, and Figure 1(b) is a plan view showing the positional relationship between the substrate and the polishing table.
FIG. 2 is a graph showing the spectrum of reflected light obtained by performing a simulation based on the interference theory of light with respect to the substrate having the structure shown in FIG. 1(a).
FIG. 3 is a cross-sectional view showing the configuration of a polishing device 110 according to an embodiment of the present invention.
FIG. 4 is a plan view showing the arrangement of a first optical head having a first light transmitting portion and a first light receiving portion, and a second optical head having a second light transmitting portion and a second light receiving portion.
Fig. 5 is a diagram showing a trajectory on the surface of a substrate drawn by the tip of the second optical head.
6 is a plan view showing another example of arrangement of the first optical head and the second optical head.
FIG. 7 is a diagram showing the trajectory drawn by the tip of the second optical head shown in FIG. 6.
Fig. 8 is a diagram showing an example in which the first optical head and the second optical head are provided with a common spectroscope and a common light source.
Fig. 9 is a plan view showing another example of arrangement of the first optical head and the second optical head.
FIG. 10 is a diagram showing a trajectory on the substrate W drawn by the first optical head.
FIG. 11 is a diagram showing a trajectory on the substrate W drawn by the first optical head.
Fig. 12 is a diagram showing the arrangement of the first optical heads when the polishing device has four first optical heads.
Fig. 13 is a diagram showing the configuration of the film thickness measuring unit.
Fig. 14 is a diagram showing the arrangement of optical heads when the polishing device has two first optical heads and two second optical heads.
Fig. 15 is a diagram showing the arrangement of optical heads when the polishing device has two first optical heads and two second optical heads.
Fig. 16 is a diagram showing the arrangement of optical heads when the polishing device has three first optical heads and three second optical heads.
Fig. 17 is a diagram showing the arrangement of optical heads when the polishing device has two first optical heads and four second optical heads.
Fig. 18 is a diagram showing the arrangement of the third optical head and the fourth optical head.
Fig. 19 is a diagram showing the arrangement of the third optical head and the fourth optical head.
Fig. 20 is a diagram showing the arrangement of the third optical head and the fourth optical head.
21 is a diagram showing the arrangement of the third optical head and the fourth optical head.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each of the following embodiments, identical or equivalent members are given the same reference numerals and redundant descriptions may be omitted. Additionally, the features shown in each embodiment can be applied to other embodiments as long as they do not contradict each other.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1(a) is a schematic diagram for explaining the principle of determining the film thickness based on the spectrum of reflected light from the substrate, and Figure 1(b) is a plan view showing the positional relationship between the substrate and the polishing table. As shown in Figure 1 (a), the substrate W to be polished includes a base layer (for example, a silicon layer) and a film formed thereon (for example, SiO ₂ having light transparency, etc. has an insulating film). The surface of the substrate W is pressed against the polishing pad 22 on the rotating polishing table 20, and the film of the substrate W is polished by sliding contact with the polishing pad 22.

The light transmitting portion 11 and the light receiving portion 12 are arranged opposite to the surface of the substrate W. The light transmitting portion 11 is connected to the light source 16 and irradiates the surface of the substrate W with light from the light source 16. The light transmitting portion 11 transmits light substantially perpendicular to the surface of the substrate W, and the light receiving portion 12 receives reflected light from the substrate W. The light emitted by the light source 16 is light of multiple wavelengths. As shown in FIG. 1(b), light is irradiated to the surface of the substrate W each time the polishing table 20 rotates once. A spectrometer 14 is connected to the light receiving unit 12. This spectrometer 14 decomposes the reflected light according to the wavelength and measures the intensity of the reflected light for each wavelength.

A processing unit 15 is connected to the spectrometer 14. This processing unit 15 reads measurement data acquired by the spectrometer 14 and generates an intensity distribution of reflected light from the measured intensity values. More specifically, the processing unit 15 generates a spectrum (spectral profile) indicating the intensity of light for each wavelength. This spectrum can be expressed as a line graph showing the relationship between the wavelength and intensity of reflected light. The processing unit 15 is further configured to determine the film thickness of the substrate W from the spectrum and further determine the polishing end point. As the processing unit 15, a general-purpose or dedicated computer can be used. The processing unit 15 executes predetermined processing steps using a program (or computer software). The processing unit 15 (control device) uses a switch 40 to switch the connection with the spectrometer 14 from one sensor head to the other sensor head at a timing when at least two sensor heads face the wafer at the same time. Control.

FIG. 2 is a graph showing the spectrum of reflected light obtained by performing a simulation based on the interference theory of light with respect to the substrate having the structure shown in FIG. 1(a). In Figure 2, the horizontal axis represents the wavelength of light, and the vertical axis represents the relative reflectance obtained from the intensity of light. This relative reflectance is an index indicating the intensity of light, and specifically, it is the ratio between the intensity of reflected light and a predetermined reference intensity. In this way, by dividing the intensity of reflected light (actual intensity) by a predetermined reference intensity, the intensity of light with the noise component removed can be obtained. The predetermined reference intensity can be, for example, the intensity of reflected light obtained when a silicon wafer without a film is polished in the presence of water. Additionally, the intensity of reflected light itself may be used rather than the relative reflectance.

A spectrum is an array of light intensities arranged in order of wavelength, and represents the intensity of light at each wavelength. This spectrum changes depending on the film thickness of the substrate. This is a phenomenon caused by interference of light waves. That is, the light irradiated to the substrate is reflected at the interface between the medium and the film, and at the interface between the film and the layer below the film, and the waves of light reflected at these interfaces interfere with each other. The interference method of this light wave changes depending on the thickness of the film (that is, the optical path length). For this reason, the spectrum of reflected light returning from the substrate changes depending on the thickness of the film, as shown in FIG. 2.

The processing unit 15 is configured to determine the film thickness from the obtained spectrum. As a method for determining the film thickness from the spectrum, known techniques can be used. For example, there is a method of estimating the film thickness by comparing a spectrum obtained during polishing (actual spectrum) with a previously prepared reference spectrum. This method compares the spectrum at each time point during polishing with a plurality of reference spectra, and determines the film thickness from the reference spectrum whose shape is closest to the spectrum. A plurality of reference spectra are prepared in advance by polishing a sample substrate of the same type as the substrate to be polished. Each reference spectrum is related to the film thickness from which the reference spectrum was acquired. Therefore, the current film thickness can be estimated from the reference spectrum whose shape is closest to the spectrum obtained during polishing.

The processing unit 15 is connected to a control unit 19 that determines polishing conditions such as polishing load for the substrate. The spectrum generated by the processing unit 15 is transmitted to the control unit 19. The control unit 19 determines the optimal polishing load for obtaining the target film thickness profile based on the spectrum obtained during polishing, and controls the polishing load on the substrate, as will be described later.

FIG. 3 is a cross-sectional view showing the configuration of a polishing device 110 according to an embodiment of the present invention. The polishing device 110 includes a polishing table 20 that supports the polishing pad 22, a polishing head 24 that holds the substrate W and presses it against the polishing pad 22, and a polishing pad 22. It is provided with a polishing liquid supply mechanism 25 that supplies polishing liquid (slurry). The polishing table 20 is connected to a motor (not shown) disposed below and can rotate around its axis. The polishing pad 22 is fixed to the upper surface of the polishing table 20 .

The upper surface 22a of the polishing pad 22 constitutes a polishing surface for polishing the substrate W. The polishing head 24 is connected to a motor and a lifting cylinder (not shown) through a polishing head shaft 28. As a result, the polishing head 24 can be raised and lowered and rotated around the polishing head shaft 28. The substrate W is held on the lower surface of the polishing head 24 by vacuum suction or the like.

The substrate W held on the lower surface of the polishing head 24 is rotated by the polishing head 24 and is pressed by the polishing head 24 against the polishing pad 22 on the rotating polishing table 20. . At this time, the polishing liquid is supplied from the polishing liquid supply mechanism 25 to the polishing surface 22a of the polishing pad 22, and the polishing liquid is present between the surface of the substrate W and the polishing pad 22. The surface of (W) is polished. The relative movement mechanism that brings the substrate W and the polishing pad 22 into sliding contact is comprised of the polishing table 20 and the polishing head 24 .

The polishing table 20 is formed with holes 30A and 30B opening at its upper surface. Additionally, through holes 31A and 31B are formed in the polishing pad 22 at positions corresponding to the holes 30A and 30B. The hole 30A and the through hole 31A are in communication, and the hole 30B and the through hole 31B are in communication. The through holes 31A and 31B are open in the polished surface 22a. Holes 30A, 30B are connected to a liquid supply source 35 through a liquid supply path 33 and a rotary joint 32. During polishing, water (preferably pure water) as a transparent liquid is supplied from the liquid supply source 35 to the holes 30A and 30B. Water fills the space formed by the lower surface of the substrate W and the passage holes 31A and 31B, and is discharged through the liquid discharge passage 34. The polishing liquid is discharged together with water, thereby securing the optical path. The liquid supply path 33 is provided with a valve (not shown) that operates in synchronization with the rotation of the polishing table 20. This valve operates to stop the flow of water or reduce the flow rate of water when the substrate W is not positioned over the passage holes 31A and 31B. Instead of securing an optical path by supplying water through a hole, a polishing pad with a transparent window may be attached to the polishing table.

The polishing device 110 has a light source 16 that emits light. The first optical head 13A, while moving across the substrate W, irradiates light from the light source 16 to an area including the center 50 of the substrate W, and emits light from the substrate W Receives reflected light. The second optical head 13B moves along the periphery of the substrate W, irradiates light from the light source 16 to the periphery of the substrate W, and receives reflected light from the substrate W.

The polishing device 110 is equipped with an optical film thickness measuring unit that measures the film thickness of the substrate according to the method described above. This optical film thickness measuring unit includes light sources 16a and 16b that emit light, a first light transmitting portion 11a that irradiates the light emitted from the light source 16a onto the surface of the substrate W, and A first light receiving part 12a that receives the returned reflected light, a second light transmitting part 11b that irradiates the light emitted from the light source 16b onto the surface of the substrate W, and a second light transmitting part 11b that radiates the light emitted from the light source 16b onto the surface of the substrate W A second light receiving unit 12b that receives light, spectrometers 14a and 14b that decompose the reflected light from the substrate W according to the wavelength and measure the intensity of the reflected light over a predetermined wavelength range, and spectrometers 14a and 14b It is provided with a processing unit 15 that generates a spectrum from the measurement data acquired by and determines the film thickness of the substrate W based on this spectrum. The spectrum represents the intensity of light distributed over a predetermined wavelength range and represents the relationship between the intensity of light and the wavelength.

The first light transmitting part 11a, the first light receiving part 12a, the second light transmitting part 11b, and the second light receiving part 12b are made of optical fibers. The first light transmitting portion 11a and the first light receiving portion 12a constitute the first optical head (first sensor head) 13A, and the second light transmitting portion 11b and the second light receiving portion 12b constitute the first optical head (first sensor head) 13A. It constitutes 2 optical heads (second optical heads) 13B. The first light transmitting portion 11a is connected to the light source 16a, and the second light transmitting portion 11b is connected to the light source 16b. The first light receiving unit 12a is connected to the spectroscope 14a, and the second light receiving unit 12b is connected to the spectroscope 14b.

In Fig. 3, only one first optical head 13A and one second optical head 13B are shown, but this is due to the position of the cross-sectional view on the table. Details of the number and arrangement of the first optical head 13A and the second optical head 13B will be described later. In Fig. 3, the spectroscope 14 is shown as a spectrometer 14a and a spectroscope 14b, but this is to avoid cluttering the drawing and facilitate understanding. This does not mean that there are two spectroscopes 14, but in this embodiment, there is only one spectroscope 14. As will be described later, the first optical head 13A and the second optical head 13B are connected to one spectrometer 14.

As the light sources 16a and 16b, a light source that emits light having multiple wavelengths, such as a light emitting diode (LED), a halogen lamp, or a xenon flash lamp, can be used. The first light transmitting portion 11a, the first light receiving portion 12a, the second light transmitting portion 11b, the second light receiving portion 12b, the light sources 16a and 16b, and the spectrometers 14a and 14b are polishing table 20. ) and rotates together with the polishing table 20. The first light transmitting portion 11a and the first light receiving portion 12a are disposed within the hole 30A formed in the polishing table 20, and the tip of each is located near the surface to be polished of the substrate W. Similarly, the second light transmitting portion 11b and the second light receiving portion 12b are disposed within the hole 30B formed in the polishing table 20, and the tip of each is located near the surface to be polished of the substrate W, there is.

The first light transmitting part 11a and the first light receiving part 12a are arranged perpendicularly to the surface of the substrate W, and the first light transmitting part 11a irradiates light perpendicular to the surface of the substrate W. It is supposed to be done. Likewise, the second light transmitting portion 11b and the second light receiving portion 12b are arranged perpendicular to the surface of the substrate W, and the second light transmitting portion 11b transmits light perpendicular to the surface of the substrate W. is supposed to be investigated.

The first light transmitting portion 11a and the first light receiving portion 12a are disposed opposite to the center of the substrate W held by the polishing head 24. Therefore, as shown in (b) of FIG. 1, each time the polishing table 20 rotates, the tips of the first light transmitting portion 11a and the first light receiving portion 12a move across the substrate W. And, light is irradiated to the area including the center of the substrate W. This is because the first light transmitting portion 11a and the first light receiving portion 12a pass through the center of the substrate W, including the film thickness of the center of the substrate W, and the film thickness of the entire surface of the substrate W. This is to measure. The processing unit 15 may generate a film thickness profile (film thickness distribution) based on the measured film thickness data.

On the other hand, the second light transmitting portion 11b and the second light receiving portion 12b are disposed opposite to the peripheral portion 68 of the substrate W held by the polishing head 24. The tips of the second light transmitting portion 11b and the second light receiving portion 12b move along the peripheral portion 68 of the substrate W each time the polishing table 20 rotates. Accordingly, light is irradiated to the peripheral portion 68 of the substrate W each time the polishing table 20 rotates.

During polishing of the substrate W, light is irradiated to the substrate W from the first light transmitting portion 11a and the second light transmitting portion 11b. The light from the first light transmitting portion 11a is reflected by the surface of the substrate W and is received by the first light receiving portion 12a. Light from the second light transmitting portion 11b is reflected by the surface of the substrate W and received by the second light receiving portion 12b. While light is irradiated to the substrate W, water is supplied to the hole 30A and the through hole 31A, thereby forming the ends of the first light transmitting portion 11a and the first light receiving portion 12a, The space between the surfaces of the substrate W is filled with water. Similarly, while light is irradiated to the substrate W, water is supplied to the hole 30B and the through hole 31B, thereby leading to each tip of the second light transmitting portion 11b and the second light receiving portion 12b. The space between and the surface of the substrate W is filled with water.

The spectrometer 14 decomposes the reflected light sent from the first light receiving unit 12a according to the wavelength and measures the intensity of the reflected light for each wavelength. Similarly, the spectrometer 14 decomposes the reflected light sent from the second light receiving unit 12b according to the wavelength and measures the intensity of the reflected light for each wavelength. The processing unit 15 generates a spectrum representing the relationship between the intensity of the reflected light and the wavelength from the intensity of the reflected light measured by the spectrometer 14. Additionally, the processing unit 15 determines the current film thickness of the substrate W from the obtained spectrum using a known technique as described above.

FIG. 4 shows a first optical head 13A having a first light transmitting portion 11a and a first light receiving portion 12a shown in FIG. 3, and a second light transmitting portion 11b and a second light receiving portion 12b. 2 This is a plan view showing the arrangement of the optical head 13B. Other optical heads are not shown. As shown in FIG. 4, the center of the substrate W is located on the trace drawn by the first optical head 13A, and the peripheral portion 68 of the substrate W is located on the trace drawn by the second optical head 13B. It is located. As can be seen from FIG. 4 , the second optical head 13B moves across only the peripheral portion 68 of the substrate W, and its moving direction is substantially the circumferential direction of the substrate W.

The first optical head 13A and the second optical head 13B are arranged along the radial direction of the polishing table 20. Therefore, the angle formed by the line connecting the center O of the first optical head 13A and the polishing table 20 and the line connecting the center O of the second optical head 13B and the polishing table 20 is 0 degrees. The 2nd optical head 13B is arrange|positioned outside the 1st optical head 13A with respect to the radial direction of the polishing table 20. That is, the distance between the second optical head 13B and the center O of the polishing table 20 is longer than the distance between the first optical head 13A and the center O of the polishing table 20.

FIG. 5 is a diagram showing the trajectory on the surface of the substrate W drawn by the tip of the second optical head 13B. More specifically, FIG. 5 shows the trajectory drawn by the second optical head 13B when the polishing table 20 rotates twice. As can be seen from FIG. 5 , the second optical head 13B moves along the peripheral portion 68 of the substrate W along with the rotation of the polishing table 20 . As a result, the number of measurement points on the peripheral portion 68 of the substrate W becomes larger than the number of measurement points in a CMP device that does not perform measurement on the peripheral portion 68. Therefore, the film thickness of the peripheral portion 68 of the substrate W can be accurately determined from more measurement data.

Here, in this specification, the peripheral portion 68 of the substrate is the outermost annular portion of the substrate, as shown in FIG. 5, and its width is, for example, 10 mm to 20 mm. For example, in the case of a substrate with a diameter of 300 mm, the width of the peripheral portion 68 is approximately 10 mm. The peripheral portion 68 of the substrate is an area where devices are formed. However, it is not limited to 10 mm to 20 mm. The peripheral portion 68 of the substrate is an area most susceptible to the influence of the polishing load or polishing liquid during polishing, and is an area where the film thickness is likely to change significantly during polishing compared to other areas of the substrate. Therefore, high-precision film thickness monitoring is required during polishing.

In in-situ measurements that measure the film thickness of a substrate during polishing, the film thickness measurement may be affected by the polishing liquid. In particular, in an optical film thickness measuring device, light is blocked by the polishing liquid, and there are cases where highly accurate film thickness measurement cannot be performed. Therefore, in order to exclude the influence of the polishing liquid on the film thickness measurement, the substrate may be polished (water polished) while regularly supplying pure water to the polishing pad 22, and the film thickness of the substrate may be measured while the pure water is supplied. .

The processing unit 15 creates a film thickness profile by combining the film thickness value acquired using the first optical head 13A and the film thickness value acquired using the second optical head 13B.

FIG. 6 is a plan view showing another example of arrangement of the first optical head 13A and the second optical head 13B. This is a plan view showing a possible arrangement example of the second optical head 13B disposed on the peripheral portion 68. The arrangement of the first optical head 13A and the second optical head 13B shown in FIG. 6 is basically the same as the arrangement shown in FIG. 4, but the second optical head 13B is the first optical head 13A. ) in that it is arranged closer to the center O of the polishing table 20. That is, in the example shown in FIG. 6, the 2nd optical head 13B is located inside the 1st optical head 13A with respect to the radial direction of the polishing table 20. Therefore, the distance between the second optical head 13B and the center O of the polishing table 20 is shorter than the distance between the first optical head 13A and the center O of the polishing table 20. In FIG. 6 , similar to FIG. 4 , the other first optical heads 13A and the like are not shown.

FIG. 7 is a diagram showing the trajectory of the tip of the second optical head 13B shown in FIG. 6, and shows the trajectory when the polishing table 20 rotates twice. As can be seen from FIG. 7 , the second optical head 13B moves along the peripheral portion 68 of the substrate W as the polishing table 20 rotates. Therefore, the film thickness of the peripheral portion 68 of the substrate W can be measured from more measurement points. Moreover, from the contrast between the trace shown in FIG. 5 and the trace shown in FIG. 7, the trace of the 2nd optical head 13B shown in FIG. 7 is longer than the trace of the 2nd optical head 13B shown in FIG. 5. Able to know. Therefore, in the arrangement shown in FIG. 6, the film thickness of the peripheral portion 68 of the substrate W can be measured at more measurement points.

In the arrangement shown in the embodiment of the present application, one spectrometer can receive reflected light from the first optical head 13A and reflected light from the second optical head 13B at different times. That is, in one spectrometer, even if reflected light from the center of the substrate W and reflected light from the peripheral portion 68 of the substrate W are received, these reflected lights do not overlap within the spectrometer. The provision of such a common spectrometer will be explained with reference to FIG. 8.

As shown in FIG. 8, the first light receiving section 12a and the second light receiving section 12b are connected to the spectrometer 14 through an optical switch 40 (switcher). The optical switch 40 selectively connects at least two sensor heads to the spectroscope 14. Here, an optical switch is a device that switches the transmission path of light. A typical optical switch has a structure including a mirror to change the direction of light, and is configured to change the light transmission path by reflecting incident light with the mirror. In addition to optical switches using mirrors, waveguide-type optical switches using materials whose refractive index changes depending on inputs such as heat or electricity are sometimes used. As the optical switch 40, such known optical switches can be used. In FIG. 8, either of the two inputs is connected to the spectrometer 14, but any number of inputs can be connected to the spectroscope 14 via the optical switch 40. Additionally, a shutter may be used instead of an optical switch.

In the above-described configuration, when the first optical head 13A moves across the substrate W, the spectroscope 14 is connected to the first light receiving portion 12a by the optical switch 40. Meanwhile, when the second optical head 13B moves across the substrate W, the spectroscope 14 is connected to the second light receiving portion 12b by the optical switch 40. In this way, by using the optical switch 40, the spectrometer 14 can be alternately connected to the first optical head 13A or the second optical head 13B. How to connect the plurality of optical heads and the optical switch 40 when the plurality of optical heads move simultaneously across the substrate W will be described later.

In the example shown in FIG. 1, the second optical head 13B is disposed outside the first optical head 13A with respect to the radial direction of the polishing table 20, but as shown in FIG. 9, The second optical head 13B may be disposed inside the first optical head 13A in the radial direction of the polishing table 20. That is, the distance between the second optical head 13B and the center O of the polishing table 20 may be shorter than the distance between the first optical head 13A and the center O of the polishing table 20.

Here, the problem of the arrangement of the optical head disclosed in Japanese Patent No. 6470365, which is a prior art, will be described. In Figure 9, only one first optical head 13A and one second optical head 13B are shown. A polishing device that has only one first optical head 13A and one second optical head 13B and is arranged as shown in FIG. 9 is disclosed in Japanese Patent No. 6470365. In addition, in the embodiment of the present application, at least two first optical heads 13A are arranged. The trajectory of the first optical head 13A in FIG. 9 is shown in FIG. 10.

FIG. 10 is a diagram showing a trajectory on the substrate W drawn by the first optical head 13A when the polishing table 20 and the polishing head 24 are rotated under certain conditions. As shown in FIG. 10, under this condition, the trajectory of the first optical head 13A rotates 36 degrees each time the polishing table 20 rotates, so the sensor trace changes to the substrate W every 5 scans. ) The image rotates half a turn. When the first optical head 13A scans the substrate W five times, the first optical head 13A scans approximately 60% of the substrate W.

Regarding the trajectory of the second optical head 13B, as can be seen from FIGS. 5 and 7, only 5 times 36 degrees (180 degrees), that is, only about 60% of the peripheral portion 68 of the substrate W can be scanned. does not exist. In order to scan the entire substrate W including the peripheral portion 68, in the case of having only one first optical head 13A and one second optical head 13B, the polishing table 20 has 10 There is a need to rotate. FIG. 11 shows the trace on the substrate W drawn by the first optical head 13A when the polishing table 20 rotates 10 times.

With the miniaturization of devices, improvement in polishing precision is essential. To improve polishing precision, it is necessary to further improve measurement resolution. There is a need to increase the number of sensor heads to improve measurement resolution. If the number of signal processing units that receive and process signals output from the sensor heads increases according to the number of sensor heads, the polishing device becomes larger. This problem is more pronounced when using an optical sensor for film thickness measurement than when using an eddy current sensor. This is because the spectrometer, which is the signal processing unit of the optical sensor, is larger in size than the signal processing unit of the eddy current sensor. As the size increases, this becomes a problem if the installation area of the device is limited. Additionally, there is a problem that semiconductor productivity converted into production per unit area of the device decreases.

In one embodiment of the present application, in order to solve this problem, the following polishing device is provided, and the second half (or first half, or part) of the sensor trace on the surface of the substrate W is alternately measured using a plurality of sensors. , there is no case in which multiple spectrometers 14 are installed. Additionally, this embodiment improves the measurement resolution and can also determine the film thickness profile within the substrate W plane in a short time.

Fig. 12 is a diagram showing the arrangement of the first optical heads when the polishing device has four first optical heads. The polishing apparatus of the present embodiment shown in FIG. 12 moves across the substrate W and transmits a signal (reflected light) regarding the film thickness of the substrate W in the area including the center 50 of the substrate W. ) a plurality of first optical heads (131, 132, 133, 134) that detect, and at least two (four in this embodiment) of the plurality of first optical heads (131, 132, 133) , 134) is provided with one spectrometer 14 (signal processing unit) that receives and processes the signal output. The spectrometer 14 outputs, for example, a spectrum of reflected light. The polishing table 20 is rotatable around the axis of the polishing table 20, and the plurality of first optical heads 131, 132, 133, and 134 face the area including the center of the substrate W. It is arranged in the area of the polishing table 20.

The four first optical heads 131, 132, 133, and 134 rotate on a circular trajectory 52 around the axis O of the polishing table 20. While the plurality of first optical heads 131, 132, 133, and 134 are moving, there is a timing when at least two (two in this embodiment) first optical heads simultaneously face the substrate W. . In this figure, the first optical heads 131 and 132 face the substrate W at the same time. In this drawing, four first optical heads 131, 132, 133, and 134 are arranged at equal intervals of 90 degrees. Each time the polishing table 20 rotates 90 degrees, the first optical heads 131 and 132, the first optical heads 131 and 134, the first optical heads 134 and 133, and the first optical heads 133, 132), and simultaneously faces the substrate W. How many first optical heads simultaneously face the substrate W depends on the size of the radius of the substrate W and the position of the first optical head.

When facing simultaneously, (1) any one of the at least two first optical heads is connected to the spectrometer 14 (signal processing unit), or (2) the at least two first optical heads are connected at different times. It is connected to the spectrometer 14. In this embodiment, the connection method (1) is possible. Embodiments in which the connection method (2) is possible will be described later. In this embodiment, the time for which one first optical head is connected to the spectrometer 14 can vary. For example, (1) the first optical head 131 is connected to the spectrometer 14 in the first half 54 of the entire 58 of the trajectory 52 when facing the substrate W, ( 2) connected to the spectroscope 14 in the latter half 56 of the entire 58 of the trace 52, (3) connected to the spectrometer 14 in the entire 58 of the trace 52, (4) ) It is possible to connect with the spectrograph 14 in the middle of the entire 58 of the trace 52.

When the four first optical heads are connected to the spectrometer 14 in the first half 54 of the trajectory 52, the time for almost uniformly scanning the entire surface of the substrate W is 10 turns of the polishing table 20. It is reduced from the time required to turn. When connected to the spectrometer 14 in the second half 56 of the trajectory 52, the entire substrate W is scanned almost equally in the same time as when connected to the spectroscope 14 in the first half 54. can do. When the four first optical heads are connected to the spectrometer 14 in the entire 58 of the trace 52, the substrate W is exposed to light in half the time as when it is connected to the spectroscope 14 in the entire 54. The entire surface can be scanned almost evenly. The connection time can be half of the time required for the first optical head to pass through the entire 58 (in the case of the first half or the second half), three-quarters of the time, etc. The case of being connected to the spectrometer 14 in the middle of the trace 52 is, for example, the case of being connected in a section excluding the end of the entire 58 when film thickness data of the peripheral portion 68 is not acquired. In this way, when there are two or more first optical heads, the time to scan the entire surface of the substrate W almost equally becomes about half or less than before.

Comparing the case of being connected to the spectrometer 14 in the first half 54 of the trace 52 and the case of being connected to the spectroscope 14 in the second half 56 of the trace 52, the spectrometer 14 is connected to the spectrometer 14 in the second half 56 of the trace 52. ) is more preferable for the following reasons. In this embodiment, it is assumed that the polishing table 20 and the substrate W are rotating to the left. The first optical head 131 rotates, and water is sprayed for measurement just before entering the bottom of the substrate W. When comparing the second half (56) and the first half (54), the state of the sprayed water is stable in the second half (56). Therefore, more accurate measurement can be achieved by measuring in the latter half (56).

The four first optical heads 131, 132, 133, and 134 are connected to one spectroscope 14 via an optical switch 40, as shown in FIG. 13. Fig. 13 is a diagram showing the configuration of the film thickness measuring unit. Since signals from multiple optical heads can be processed with only one spectroscope 14, the installation area is small. Additionally, the four first optical heads 131, 132, 133, and 134 are connected to one light source 16 via an optical switch 66.

The four first optical heads 131, 132, 133, and 134 shown in Fig. 12 have the following arrangement. Among the plurality of first optical heads 131, 132, 133, and 134, a predetermined even number of first optical heads form pairs of two. That is, the two first optical heads 131 and 133 form a pair, and the first optical heads 132 and 134 form a pair.

The four first optical heads 131, 132, 133, and 134 shown in Fig. 12 have the following arrangement. In the case of this drawing, immediately after (or almost simultaneously with) the first sensor head 132 comes out of the substrate W, the first optical head 131 enters the substrate W. Immediately after (or almost simultaneously) the first sensor head 131 comes out of the substrate W, the first optical head 134 enters the substrate W. Immediately after (or approximately simultaneously with) the first sensor head 134 emerges from the substrate W, the first optical head 133 enters the substrate W. Immediately after (or almost simultaneously) the first sensor head 133 comes out of the substrate W, the first optical head 132 enters the substrate W. This is also possible in FIGS. 13 to 16 described later.

In this drawing, the lines 60 and 62 are orthogonal, but when the substrate W is smaller than the drawing, the lines 60 and 62 are not orthogonal. That is, the angle 64 becomes greater than 90 degrees. At that time, the two first optical heads 131 and 132 are at the ends of the substrate W as shown in the drawing at almost the same time, and the two first optical heads 133 and 134 are at the ends of the substrate W as shown in the drawing at almost the same time. It can be placed at the end of . In this case, immediately after (or almost simultaneously with) the first sensor head 132 comes out of the substrate W, the first optical head 131 enters the substrate W. Immediately after (or approximately simultaneously with) the first sensor head 134 emerges from the substrate W, the first optical head 133 enters the substrate W. In this case, an additional optical head may be disposed between the first optical head 132 and the first optical head 133 and/or between the first optical head 131 and the first optical head 134. This is also possible in FIGS. 13 to 16 described later.

The two first optical heads (for example, first optical heads 131 and 133) constituting the pair are positioned on substantially opposite sides with respect to the axis O. An even number of first optical heads are arranged so that the lines 60 and 62 connecting the two first optical heads constituting the pair are at equal angular intervals (90 degrees in this figure) around the axis O. there is.

The four first optical heads 131, 132, 133, and 134 shown in FIG. 12 can also be said to have the following arrangement. For a predetermined four of the plurality of first optical heads, two first optical heads 131 and 133 are located at substantially opposite sides with respect to the axis O, and the other two first optical heads (132, 134) are located at substantially opposite sides with respect to the axis. The angle 64 (90 degrees in this drawing) formed between the line 60 connecting two first optical heads and the line 62 connecting the other two first optical heads is greater than 0 degrees and less than 180 degrees. am. The connection method with the spectrometer 14 when the angle 64 is close to 0 degrees or 180 degrees will be described later.

Next, other embodiments will be described with reference to FIGS. 14 and 15. The polishing apparatus in this figure has a plurality of second optical heads 141 and 142 that detect signals related to the film thickness of the substrate W while moving along the peripheral portion 68 of the substrate, and the spectrometer 14 includes, Signals output from at least two of the plurality of second optical heads 141 and 142 (in the case of this drawing, all two) second optical heads 141 and 142 are received and processed.

There are at least two plurality of 1st optical heads 131 and 133 (two in this figure), and there are at least two plurality of 2nd optical heads 141 and 142 (two in this figure). The two first optical heads 131 and 133 are located in substantially opposite positions with respect to the axis O, and have an axis O on the line segment 70 connecting the two second optical heads 141 and 142. There is O). The angle 72 formed by the line 60 connecting the two first optical heads 131 and 133 and the line segment 70 connecting the second optical heads 141 and 142 is 0 degrees to 180 degrees.

While the plurality of first optical heads 131, 133 and the plurality of second optical heads 141, 142 rotate and move around the axis O, the plurality of first optical heads 131, 133 and the plurality of second optical heads 141, 142 There are times when at least two of the second optical heads 141 and 142 (two in this figure) face the substrate at the same time. When facing each other at the same time, any one optical head 131, 133, 141 among at least two (two in this figure) first optical heads 131, 133 or a plurality of second optical heads 141, 142, 142) is connected to the spectrometer 14. Alternatively, at least two (two in this figure) first optical heads 131 and 133 or second optical heads 141 and 142 are connected to the spectroscope 14 at different times.

(1) a case where one of the optical heads 131 and 133 is connected to the spectroscope 14, and (2) at least two (two in this figure) first optical heads 131 and 133 or second optical heads 131 and 133 are connected to the spectroscope 14. A case in which the optical heads 141 and 142 are connected to the spectroscope 14 at different times will be described below.

The case where one optical head is connected to the spectrometer 14 is, for example, a case where the two first optical heads 131 and 132 face the substrate simultaneously as shown in FIG. 12 for a short period of time. In this case, an optical head that faces the substrate for a long time is connected to the spectroscope 14. The case where at least two optical heads (two in this figure) are connected to the spectrometer 14 at different times means that, unlike FIG. 12, the two optical heads face the substrate simultaneously over a period of time rather than a short period of time. .

The case where two optical heads face the substrate simultaneously over a period of time other than a short period of time is, for example, when the angle 64 formed by the line 60 and the line 62 is less than 90 degrees in Figure 12. , for example, when the angle 64 is close to 0 degrees or 180 degrees. The length of time during which the two optical heads face the substrate simultaneously over a short period of time depends on the size of the substrate W, the distance between the axis O and the center 50, and the angle 64. .

In the case where two optical heads face the substrate simultaneously over a period of time other than a short period of time, for example, in FIGS. 14 and 15, the angle 72 formed by the line 60 and the line segment 70 is greater than 90 degrees. This is when it is small, for example when the angle 72 is close to 0 degrees or 180 degrees. The length of time during which the two optical heads face the substrate simultaneously over a short period of time depends on the size of the substrate W, the distance between the axis O and the center 50, and the angle 72. . 14 and 15, that is, when the angle 72 is 90 degrees, the two optical heads do not face the substrate at the same time. However, when angle 72 deviates from 90 degrees, for example close to 0 degrees or 180 degrees, the two optical heads face the substrate simultaneously over a period of time rather than a short period of time. This case will be explained below.

When the two optical heads face the substrate at the same time, various possibilities are possible for the times at least two (two in this figure) optical heads are connected to the spectrometer 14 at different times. Although different from Figure 15, consider the case where the first optical heads 131 and 133 and the second optical heads 141 and 142 are fixed to the polishing table 20 so that the angle 72 is 0 degrees or 180 degrees. do. That is, the second optical heads 141 and 142 are fixed to the points 80 and 82 on the circle, respectively.

When the two optical heads face the substrate at the same time, the following is possible as a method of connecting the two optical heads to the spectrometer 14 at different times. For example, (1) the first optical heads 131 and 133 are connected to the spectrometer 14 in the first half 54 of the entire 58 of the trajectory 52 when facing the substrate W, The second optical heads 141 and 142 connect to the spectroscope 14 in the latter half 86 of the entire trajectory 74 when facing the substrate W. As another method, (2) the first optical heads 131 and 133 are connected to the spectrometer 14 in the latter half 56 of the entire 58 of the trajectory 52, and the second optical heads 141 and 142 are connected to the substrate. It is connected to the spectrometer 14 in the first half 84 of the entire 76 of the trajectory 74 when facing (W).

In the case of Figs. 14 and 15, the first optical head 131 passes 10 trajectories shown in Fig. 11 in the order of numbers shown in the drawings as the polishing table 20 rotates. The first optical head 133 on the opposite side of the first optical head 131 moves the ten trajectories shown in FIG. 11, 6, 7, 8, 9, and 10, as the polishing table 20 rotates. , passes in the order of numbers 1, 2, 3, 4, and 5. When the first optical heads 131 and 133 are connected to the spectroscope 14 in the first half 54 of the entire 58 of the trajectory 52 when facing the substrate W, the first optical head 131 , 133) is connected to the spectrometer 14 throughout the ten trajectories shown in FIG. 11 (part from the starting point of the trajectory to the center 50). As a result, when the polishing table 20 rotates 5 times, the entire substrate W can be scanned almost evenly. That is, compared to the conventional case of FIG. 9 using only one first optical head 131 (the polishing table 20 needs to rotate 10 times), when the polishing table 20 rotates 5 times, the substrate The entire area of (W) can be scanned almost evenly. Compared to the prior art shown in FIG. 9, the measurement time is shortened, and more data of the peripheral portion 68 can be acquired. Additionally, the difference between FIGS. 14 and 15 is that, in FIG. 15 , the second optical heads 141 and 142 are disposed closer to the center 50 compared to FIG. 14 . As a result, compared to FIG. 14 in FIG. 15 , more measurement data of the peripheral portion 68 can be acquired.

Next, another embodiment will be described with reference to FIG. 16. In the polishing device of this figure, the first optical heads 131, 132 of a predetermined number of the plurality of first optical heads 131, 132, and 133 (in this figure, all three of the three first optical heads) 133), and the second optical heads 141, 142, 143 of the predetermined number of the plurality of second optical heads 141, 142, and 143 (in this figure, all three of the three second optical heads) Regarding, three second optical heads (141, 141, 142, 143), one each is placed.

In other words, the arrangement in this figure connects the axis O and the second optical heads 141, 142, and 143 when the second optical heads 141, 142, and 143 enter the substrate W. One each of the three first optical heads 131, 132, and 133 is disposed on the lines 88, 90, and 92. Additionally, the three lines 88, 90, and 92 are arranged at equal intervals around the axis O, or at intervals of 120 degrees in this drawing. The three lines 88, 90, and 92 do not need to be arranged at equal intervals around the axis O.

In this embodiment, there are times when the two optical heads face the substrate simultaneously. At this time, the following is possible as a method of connecting two optical heads, for example, the first optical head 131 and the second optical head 141, with the spectrometer 14 at different times. For example, (1) the first optical head 131 is connected to the spectroscope 14 in the first half 54 of the entire 58 of the trajectory 52 when facing the substrate W, and the second The optical head 141 is connected to the spectrometer 14 in the latter half 86 of the entire trajectory 74 when facing the substrate W. As another method, (2) the first optical head 131 is connected to the spectroscope 14 in the latter half 56 of the entire 58 of the trajectory 52, and the second optical head 141 is connected to the substrate W. When facing each other, the first half 84 of the entire trajectory 74 76 is connected to the spectrometer 14.

Next, another embodiment will be described with reference to FIG. 17. In the polishing apparatus of this figure, two of the plurality of first sensor heads 131 and 132 (in this figure, two first optical heads 131 and 132) and the plurality of second sensor heads ( For any four of 141, 142, 143, 144 (in this drawing, all four of the four second optical heads), the two first sensor heads 131, 132 are positioned with respect to the axis O. They are practically on opposite sides of each other. There is an axis O on the first line segment 94 connecting the two second sensor heads 141 and 142. There is an axis O on the second line segment 96 connecting the other two second sensor heads 143 and 144. The angle 104 formed by the first line segment 94 and the second line segment 96 ranges from 0 degrees to 180 degrees. In this drawing, the angle of angle 104 is less than 90 degrees.

The four second sensor heads 141, 142, 143, and 144 are arranged symmetrically with respect to the third line 98 connecting the two first sensor heads 131 and 133. Among the angles formed by the third line 98 and the first line segment 94, the smallest angle (in the case of this drawing, the angle 100) is less than 90 degrees. Among the angles formed by the first line segment 94 and the second line segment 96, the minimum angle (in the case of this drawing, the angle 102) is less than 90 degrees.

In the case of this drawing, immediately after (or almost simultaneously with) the second sensor head 143 comes out of the substrate W, the first optical head 131 enters the substrate W. The first optical head 131 passes through the front panel 54, and immediately (or almost simultaneously) after passing through the front panel 54, the second sensor head 141 enters the substrate W. Immediately after (or approximately simultaneously with) the second sensor head 141 emerges from the substrate W, the second optical head 144 enters the substrate W. Immediately after (or approximately simultaneously with) the second optical head 144 emerges from the substrate W, the first optical head 133 enters the substrate W. The first optical head 133 passes through the front panel 54, and immediately (or almost simultaneously) after passing through the front panel 54, the second sensor head 142 enters the substrate W. This is repeated below. This allows a lot of data to be acquired efficiently.

12 to 17, an example in which two first optical heads or second optical heads face the substrate has been described, but it is also possible for three or more first optical heads or second optical heads to face the substrate. . This is possible by reducing the time per unit connected to the spectroscope 14 compared to the two cases. Moreover, as shown in FIG. 4, the 2nd optical head may exist outside the 1st optical head when viewed from the axis center. A plurality of optical heads are connected to one spectroscope 14, but when the number of optical heads is large, all optical heads may not be connected to one spectroscope 14, and a second spectrometer 14 may be provided. Additionally, in the above embodiment, the first sensor head detected a signal related to the film thickness of the substrate in the region including the center of the substrate, but the signal related to the film thickness of the substrate was detected in the region not including the center of the substrate. You may detect a signal. Although the second sensor head detects a signal related to the film thickness of the substrate while moving along the peripheral edge of the substrate, it may detect a signal related to the film thickness of the substrate while moving other than the peripheral edge of the substrate.

In the polishing method for polishing the substrate W, which is one embodiment of the present invention, the polishing table 20 holds the polishing pad 22. The polishing head 24 presses the surface of the substrate W against the polishing pad 22 . The plurality of first sensor heads 131, 132, 133, and 134 move across the substrate W and detect signals related to the film thickness of the substrate W. One signal processing unit 14 receives and processes signals output from the plurality of first sensor heads 131, 132, 133, and 134. Diverter 40 selectively connects at least two sensor heads to spectrometer 14. The control device 15 controls the switch 40 to switch the connection with the spectrometer 14 from one sensor head to the other sensor head when at least two sensor heads face the substrate W at the same time. .

In each of the above-described examples, an optical head is provided, but the present invention is not limited to an optical film thickness measuring device and can also be applied to other film thickness measuring devices such as eddy current sensors. For example, according to the example shown in FIG. 14 described above, the first eddy current sensor, which is a film thickness sensor, may be disposed to face the center of the substrate, and the second eddy current sensor may be disposed to face the peripheral portion of the substrate. At this time, the switch (electrical switch) selectively connects at least two sensors to the signal processing unit (electronic circuit). One signal processing unit receives and processes signals output from at least two eddy current sensors among the plurality of eddy current sensors. The control device (electronic circuit) controls the switcher to switch the connection with the signal processing unit from one eddy current sensor to the other eddy current sensor at a timing when at least two eddy current sensors face the substrate at the same time.

In each of the above-described examples, the control device 15 uses a switch 40 to switch the connection with the spectroscope from one optical head to the other optical head at a timing when at least two optical heads simultaneously face the substrate. is controlling.

However, considering response delay (communication delay, operation delay of each part, etc.) and fluctuation in operation due to temperature change, the connection with the spectrometer must be connected to one side after moving from a position not facing the board to a position facing the board. In the method of switching from one optical head to the other optical head, the switching may be slow. In other words, data acquisition at the end becomes insufficient.

So, at least one of the two optical heads is not facing the substrate, that is, the third optical head (one sensor head) of the at least two optical heads is facing the substrate, and the fourth of the at least two optical heads is not facing the substrate. At a timing when the optical head (the other sensor head) does not face the substrate, the processing unit 15 establishes a connection with the spectrometer 14 from the third optical head 231 facing the substrate W. There are cases where it is desirable to control the switch 40 to initiate a switch process to switch to the fourth optical head 232 that does not oppose W). Additionally, “opposite the substrate” means that “a film structure to be measured exists in at least a part of the spot area of the light output by the optical head, and the optical head is located at a position where film thickness information within the spot area can be obtained.” . This embodiment will be explained with reference to FIG. 18.

The geometric arrangement of the optical head (sensor head) in this figure is the same as that in FIG. 16. That is, with respect to geometric arrangement, the third optical head 231 (third sensor head) corresponds to the first optical head 131, and the fourth optical head 232 (fourth sensor head) corresponds to the first optical head ( 132), and the fifth optical head 233 corresponds to the first optical head 133. The sixth optical heads 241, 242, and 243 are located at positions corresponding to the second optical heads 141, 142, and 143, respectively.

However, the control method of the optical head is different. In this figure, the third optical head 231, the fourth optical head 232, and the fifth optical head 233 are connected to the spectrometer 14 through the switch 40. The sixth optical heads 241, 242, and 243 are connected to a spectrometer (not shown) different from the spectroscope 14 through a switch 40. That is, the third optical head 231, fourth optical head 232, and fifth optical head 233 passing through the center of the substrate W are the sixth optical head 241 passing through the end of the substrate W. , 242, 243), no conversion is made.

18 shows the third optical head when switching the connection with the spectroscope 14 from the third optical head 231 facing the substrate W to the fourth optical head 232 not facing the substrate W. The positions of 231 and the fourth optical head 232 are shown. The timing of the transition will be explained. Optical heads 231, 232, 233 move on a trajectory 156. The direction of movement (i.e., the direction of rotation of the polishing table 20) is indicated by an arrow 154. When the processing unit 15 starts the switching process to switch from the third optical head 231 to the fourth optical head 232, the fourth optical head 232 is at a position 158 on the trajectory 156. At this time, the third optical head 231 is located at the first end 150 of the substrate W. The transition to the fourth optical head 232 is complete when the fourth optical head 232 has reached the second end 152 of the substrate W.

Here, “switching is complete” means that the fourth optical head 232 can acquire a signal according to the film thickness of the substrate W. Additionally, it is not necessary that the transition is complete when the fourth optical head 232 reaches the end 152. For example, switching is completed before end 152 and data acquisition is started. At that time, since the light from the fourth optical head 232 does not reach the substrate W, the data is not used for end point detection or the like. Additionally, switching may be completed when the third optical head 231 is located inside the substrate W rather than the end portion 150.

In other words, the problems of the prior art such as “switching is slow” or, due to this, “data acquisition at the end of the substrate W is insufficient” can be solved by the embodiment in FIG. 18, but it is unclear when the switching will be completed. , is decided according to need. In a case where the rotation speed of the polishing table 20 is fast and the number of sensors on the trace 156 is particularly large, in order to perform measurement in the desired area from which data is to be acquired, the optical head preceding on the trace 156 must be moved to the substrate ( When below W), switching is necessary taking into account the response delay of switching processing to the subsequent optical head.

In this figure, during the transition the fourth optical head 232 moves from position 158 to the second end 152. When to start the switch, that is, how far before the second end 152 the switch should start, depends on the following factors. In other words, the faster the rotation speed of the polishing table 20 and the larger the response delay, the faster the start of switching. In other words, the faster start of switching means that the distance between the position 158 where switching starts and the second end 152 becomes longer.

Also, in this figure, the third optical head 231 is located at the first end 150 at the start of the changeover, and the third optical head 231 is positioned between the first end 150 and the second end 152. In some cases, the transition begins when there is. This case is shown in Figure 19. In FIG. 19 , the transition begins when the third optical head 231 is positioned at position 161 and the fourth optical head 232 is positioned at position 162. That is, the faster the rotation speed of the polishing table 20, the larger the response delay, and the greater the number of optical heads arranged on the trajectory 156, the position of the third optical head 231 at the start of the changeover. becomes closer to the second end 152. For example, when the third optical head 231 has not advanced halfway across the substrate, that is, the third optical head 231 is positioned between the center 50 and the second end 152 of the substrate W. There may be cases where it is necessary to initiate a conversion process.

In Fig. 19, taking this into consideration, the position before the third optical head 231 (one sensor head) facing the substrate W reaches the end 150 of the trajectory passing under the substrate W. In (161), switching processing from the third optical head 231 to the fourth optical head 232 (the other sensor head) that does not face the substrate W is started. The third optical head 231 starts switching, leaving a measurable area between the position 161 and the end 150. When the conversion process is complete, fourth optical head 232 is located at position 170. A switch is made from the sensor facing the substrate to the sensor head not facing the substrate.

In FIGS. 18 and 19 and FIGS. 20 and 21 described later, the fourth optical head 232 is located near the second end 152 when switching processing is started. The fourth optical head 232 passes through the second end 152 of the substrate W when moving from a nearby position that does not face the substrate W to a position that faces the substrate W. The third optical head 231 passes through the first end 150 of the substrate W when moving from a position facing the substrate W to a position not facing the substrate W. When starting the switching process from the third optical head 231 to the fourth optical head 232, the fourth optical head 232 is located near the second end 152.

Here, the vicinity of the second end 152 is as follows, for example. It is a peripheral area of the second end 152 where the fourth optical head 232 can be present, during the period from when the processing unit 15 initiates switching until the switching is completed in the diverter 40. 232 is the range of the fourth optical head 232 that can reach the second end 152, the inside of the substrate W, or the outside of the substrate W. In the case of Fig. 18, the vicinity includes at least a trajectory 156 from the position 158 to the second end 152. In the case of Fig. 18, switching starts at the position of the fourth optical head 232 shown in the figure. Switching is completed in the switch 40 when the fourth optical head 232 reaches the position of the second end 152 shown in the figure. “Switching is complete” means that film thickness measurement by the fourth optical head 232 is possible. There is no problem if the transition is completed in front of the second end 152 with some margin. The vicinity range is, for example, an area on both sides of the second end 152 on the trace 156, a range of 1/8 of the total length of the trace 156, and a range of 1/4 in total. If the vicinity is expressed as an angle, one-eighth of 360 degrees is 45 degrees, and the angle (160) shown in this figure is 45 degrees. An example of the vicinity is a range of 45 degrees on both sides from the second end 152. Since the fourth optical head 232 is at position 158, it is within 45 degrees of the trajectory 156. Additionally, the position 158 for starting the changeover does not need to be in the vicinity of the second end 152. This is because, in cases where the response delay is large, etc., the position 158 may not be in the vicinity of the second end 152.

A specific example of the conversion method is as follows. For example, the processing unit 15 determines the position or angle of the fourth optical head 232 and places the fourth optical head on the second end 152 up to a predetermined distance or angle (position 158 in FIG. 18). When (232) confirms that it has approached, switching begins. The predetermined position or angle can be determined, for example, by measuring the response delay during test polishing before actual polishing. The predetermined position or angle is preferably as close to the second end 152 as possible. This is because the polishing state can be measured up to the end of the substrate W as much as possible by the third optical head 231. The position or angle of the fourth optical head 232 can be confirmed by, for example, detecting the rotation angle of the polishing table 20.

To detect the rotation angle, for example, an angle sensor (not shown) can be used. That is, a dog (not shown) is installed on the polishing table 20 to enable position detection when the polishing table 20 rotates. An angle sensor detects this dog. For each rotation, the processing unit 15 detects the dog and then starts the switching process after a predetermined time has elapsed. Alternatively, the constant rotation phase may be determined using an encoder that detects the angle of the rotation motor of the polishing table 20.

In the embodiment shown in FIGS. 18, 19, and 20, the processing unit 15 switches to the optical head that will go under the substrate W next while one optical head is still under the substrate W. . This is because, when switching to the next optical head after one optical head exits from under the substrate W, there may be a delay due to response delay or the like.

In the polishing method for polishing the substrate W according to the embodiment of FIGS. 18, 19, and 20, the polishing table 20 holds the polishing pad 22. The polishing head 24 presses the surface of the substrate W against the polishing pad 22 . The third optical head 231, fourth optical head 232, and fifth optical head 233 move across the substrate W and detect a signal regarding the film thickness of the substrate W. One signal processing unit 14 receives and processes signals output from the third optical head 231, the fourth optical head 232, and the fifth optical head 233. The switch 40 selectively connects the third optical head 231, the fourth optical head 232, and the fifth optical head 233 to the spectroscope 14. The control device 15 connects the spectrometer 14 to the third sensor facing the substrate W at a timing when the third sensor head faces the substrate and the fourth sensor head does not face the substrate. The switch 40 is controlled to start a switching process to switch from the head to the fourth sensor head that does not face the substrate.

18, 19, and 20, an optical head is provided, but the present invention is not limited to an optical film thickness measuring device, and can also be applied to other film thickness measuring devices such as eddy current sensors. For example, according to the examples shown in FIGS. 18, 19, and 20, an eddy current sensor that is a film thickness sensor may be disposed. At this time, the switch (electrical switch) selectively connects at least two sensors to the signal processing unit (electronic circuit). One signal processing unit receives and processes signals output from at least two eddy current sensors among the plurality of eddy current sensors. The control device (electronic circuit) connects the signal processing unit to the substrate at a timing when the third sensor among the at least two sensors faces the substrate and the fourth sensor among the at least two sensors does not face the substrate. The switcher is controlled to start a switching process to switch from the third sensor facing the substrate to the fourth sensor not facing the substrate.

Normally, at the end of the substrate W, only a bevel portion (a portion on the outer periphery of the substrate W that has been chamfered and ground. The chamfered portion is a curved surface or a flat surface) exists. In the bevel portion, there is a non-device area where devices are not formed. The end portion in this specification can be interpreted as the outermost edge of the substrate W, and can also be interpreted as the boundary between the non-device area and the device area.

As an embodiment of the present invention, at a timing when one of at least two sensor heads faces the substrate and the other does not face the substrate, a switching process is performed to switch the connection with the spectrometer from the other side to one side. There are cases where the switch is controlled to start. For example, when the fourth optical head 232 has not advanced halfway across the substrate, that is, the fourth optical head 232 is positioned between the center 50 and the second end 152 of the substrate W. When doing so, there may be a case where it is necessary to start switching processing from the third optical head 231 to the fourth optical head 232. That is, after the fourth optical head 232 (one sensor head) facing the substrate W passes the starting point 152 of the trajectory passing under the substrate W, it does not face the substrate W. The switching process from the third optical head 231 (the other sensor head) to the fourth optical head 232 is started. A switch is made from a sensor head that is not facing the substrate to a sensor head that is facing the substrate.

An example of the positions of the third optical head 231 and the fourth optical head 232 at this time is shown in FIG. 20. In Figure 20, the fourth optical head 232 is located at position 164, and the third optical head 231 is located at position 166. At this time, the switching process from the third optical head 231 to the fourth optical head 232 is started. Then, when the fourth optical head 232 reaches the position 168, the switching process is completed and measurement of the film thickness is started. The fourth optical head 232 passes through the measurable area on the substrate W while moving from the starting point 152 of the trajectory to the position 168.

18 and 19 and the form of FIG. 20 can be appropriately selected depending on the quality of data acquired from the sensor head. This is because there are cases where the quality of film thickness data obtained from the first half and the second half of the substrate W is different. 18 and 19 show a form that gives priority to measurement from the end of the first half of the measurement points on the trajectory 156 of the substrate W over measurement from the second half. On the other hand, Figure 20 shows a form that gives priority to measurement from the latter part to the end rather than measurement from the first half.

As shown in FIG. 19, the polishing device 110 further includes a rocking device 172 that swings the polishing head 24 on the polishing pad 22 during polishing. When the polishing head 24 is rocked, The timing of starting the switching process is controlled according to the swing position of the polishing head 24. The rocking device 172 has a shaft 174 connected to the polishing head shaft 28 and a motor 178 that swings the shaft 174 around the rocking center 176.

The timing of starting the switching process is, for example, switched between the form in FIG. 19 and the form in FIG. 21, which will be described later, according to the rocking position. This is because even if the response delay in the switching process is the same, the positional relationship between the sensor head and the substrate changes depending on the swing position of the polishing head. When rocking, if the switching process is started from the same position on the polishing table 20, the fourth optical head 232 may or may not be able to reach the end of the substrate W until measurement is started. do. In other words, the optimal switching timing may change depending on the shaking position.

Next, the embodiment shown in FIG. 21 will be described. In this embodiment, after the third optical head 231 passes under the substrate W and comes out of the substrate W, the switching process to the fourth optical head 232 outside the substrate W is started. do. A switch is made from a sensor that is not facing the substrate to a sensor that is not facing the substrate. The completion of the switch to the fourth optical head 232, that is, the start of measurement, is performed after the fourth optical head 232 enters the inside of the substrate W. Measurement from the end 152 to the measurement start point 180 is not performed. During the measurement from position 152 (the starting point of the trace) to position 150 (the end point of the trace), the data quality of the first half of the measurement may be poor due to reasons such as the measured value not being stable. am. By not measuring in areas where data is scattered, measurement accuracy is improved.

In FIG. 21, at a timing when the fourth optical head 232 (one sensor head) of the at least two sensor heads is not facing the substrate (at the position 158), the connection with the spectrometer is made at least two times. The switcher is controlled to start a switching process for switching from the third optical head 231 (the other sensor head) to the fourth optical head 232 among the sensor heads. The switching process is completed after the fourth optical head 232 passes the starting point of the trajectory passing under the substrate. And at a timing when the third optical head 231 does not face the substrate W, the switching process is started.

In this figure, a change is made from a sensor head that is not facing the substrate to a sensor head that is not facing the substrate. Position 180 is the position of the fourth optical head 232 when the transition is complete. Measurement begins after passing the start of the measurable area.

The embodiment in FIG. 21 may also further include a rocking device that swings the polishing head on the polishing pad during polishing, and controls the timing of starting the switching process in accordance with the rocking position of the polishing head.

In the polishing method for polishing the substrate W according to the embodiment shown in FIG. 21 , the polishing table 20 holds the polishing pad 22 . The polishing head 24 presses the surface of the substrate W against the polishing pad 22 . The third optical head 231 and the fourth optical head 232 move across the substrate W and detect a signal regarding the film thickness of the substrate W. One signal processing unit 14 receives and processes signals output from the third optical head 231 and the fourth optical head 232. The switch 40 selectively connects the third optical head 231 and the fourth optical head 232 to the spectroscope 14. The control device 15 switches the connection with the signal processing unit 14 from the third optical head 231 to the fourth optical head 232 at a timing when the fourth optical head 232 does not face the substrate. The switch 40 is controlled to start the switch process. The switch 40 is controlled so that the switch process is completed after the fourth optical head 232 passes the starting point 152 of the trajectory passing under the substrate.

In Fig. 21, an optical head is provided, but the present invention is not limited to an optical film thickness measuring device and can also be applied to other film thickness measuring devices such as eddy current sensors. For example, according to the example shown in FIG. 21, an eddy current sensor that is a film thickness sensor may be disposed. At this time, the switch (electrical switch) selectively connects at least two sensors to the signal processing unit (electronic circuit). One signal processing unit receives and processes signals output from at least two eddy current sensors among the plurality of eddy current sensors. The control device (electronic circuit) is configured to initiate a switching process for switching the connection with the signal processing unit from the other sensor to one sensor at a timing when one of the at least two sensors is not facing the substrate. control. One sensor controls the switch so that the switching process is completed after passing the starting point of the trajectory passing under the substrate.

Above, examples of embodiments of the present invention have been described. However, the above-described embodiments of the invention are intended to facilitate understanding of the present invention and do not limit the present invention. The present invention can be changed and improved without departing from its spirit, and it goes without saying that equivalents thereof are included in the present invention. In addition, in the range that can solve at least part of the above-mentioned problem or achieve at least part of the effect, any combination or omission of each component described in the patent claims and specification is possible.

O: axis
11: Light transmitting part
12: light receiving unit
14: Spectrograph
15: processing unit
16: light source
20: polishing table
22: polishing pad
24: polishing head
40: optical switch
50: center
52: Trajectory
66: optical switch
68: main cast
110: polishing device
131 to 134: first sensor head
141 to 144: second sensor head
231: Third sensor head
232: Fourth sensor head

Claims (23)

It is a polishing device that polishes a substrate,
a polishing table for holding and supporting a polishing pad;
a polishing head that presses the surface of the substrate against the polishing pad;
a plurality of sensor heads that move across the substrate and detect signals related to the film thickness of the substrate;
One spectrometer that receives and processes signals output from at least two sensor heads among the plurality of sensor heads;
a diverter for selectively connecting the at least two sensor heads to the spectrometer;
having a control device,
The control device is,
At a timing when the at least two sensor heads face the substrate at the same time, controlling the switcher to switch the connection with the spectrometer from one sensor head to the other sensor head,
A polishing device characterized in that. According to paragraph 1,
The polishing table is rotatable around an axis of the polishing table, and the plurality of sensor heads are arranged in an area of the polishing table opposite to an area containing the center of the substrate. According to paragraph 2,
Among the plurality of sensor heads, a predetermined even number of sensor heads form pairs of two,
The two sensor heads constituting the pair are positioned on substantially opposite sides with respect to the axis,
A polishing device, wherein an even number of the sensor heads are arranged so that a line connecting the two sensor heads constituting the pair has equal angular spacing around the axis. According to paragraph 2,
For a given four of the plurality of sensor heads,
Two of the sensor heads are positioned on substantially opposite sides with respect to the axis, and the other two sensor heads are positioned on substantially opposite sides with respect to the axis,
A polishing device, characterized in that the angle formed by the line connecting the two sensor heads and the line connecting the other two sensor heads is greater than 0 degrees and less than 180 degrees. According to any one of claims 1 to 4,
The polishing device includes a plurality of sensor heads, including a first sensor head that detects a signal about the film thickness of the substrate in an area including the center of the substrate, and moves along the peripheral edge of the substrate to A polishing device characterized by having a second sensor head that detects a signal regarding film thickness. According to clause 5,
There are at least two plurality of first sensor heads, and there are at least two plurality of second sensor heads,
The two first sensor heads are positioned on substantially opposite sides with respect to the axis,
The axis is located on a line connecting the two second sensor heads,
A polishing device, characterized in that the angle formed by the line connecting the two first sensor heads and the line segment connecting the second sensor heads is 0 degrees to 180 degrees. According to any one of claims 1 to 4,
Regarding the predetermined number of sensor heads among the plurality of sensor heads and the predetermined number of other sensor heads among the plurality of sensor heads,
A polishing device, wherein one of each of the predetermined number of different sensor heads is disposed on a line connecting the predetermined number of sensor heads with the shaft center of the polishing table. According to any one of claims 1 to 4,
For a predetermined two of the plurality of sensor heads and another predetermined four of the plurality of sensor heads,
The two predetermined sensor heads are positioned on substantially opposite sides with respect to the axis,
The axis is located on a first line connecting two of the four sensor heads,
The axis is located on a second line segment connecting the other two sensor heads among the four predetermined sensor heads,
A polishing device, characterized in that the angle formed by the first line segment and the second line segment is 0 degrees to 180 degrees. According to clause 8,
With respect to a third line connecting the two predetermined sensor heads, the predetermined four sensor heads are arranged symmetrically,
A polishing device, wherein the minimum angle between the third line and the first line segment is less than 90 degrees, and the minimum angle between the third line and the second line segment is less than 90 degrees. It is a polishing method for polishing a substrate,
The polishing table holds and supports the polishing pad,
The polishing head presses the surface of the substrate against the polishing pad,
A plurality of sensor heads move across the substrate and detect a signal regarding the film thickness of the substrate in an area including the center of the substrate,
One spectrometer receives and processes signals output from the plurality of sensor heads,
a diverter selectively connects the at least two sensor heads to the spectrometer,
A polishing method characterized in that the control device controls a switcher to switch the connection with the spectrometer from one sensor head to the other sensor head when the at least two sensor heads face the substrate at the same time. It is a polishing device that polishes a substrate,
a polishing table for holding and supporting a polishing pad;
a polishing head that presses the surface of the substrate against the polishing pad;
a plurality of sensors that move across the substrate and detect signals related to the film thickness of the substrate;
One signal processing unit that receives and processes signals output from at least two of the plurality of sensors,
a switch for selectively connecting the at least two sensors to the signal processing unit;
having a control device,
The control device is,
At a timing when the at least two sensors simultaneously face the substrate, controlling the switch to switch the connection with the signal processing unit from one sensor to the other sensor,
A polishing device characterized in that. It is a polishing device that polishes a substrate,
a polishing table for holding and supporting a polishing pad;
a polishing head that presses the surface of the substrate against the polishing pad;
a plurality of sensor heads that move across the substrate and detect signals related to the film thickness of the substrate;
One spectrometer that receives and processes signals output from at least two sensor heads among the plurality of sensor heads;
a diverter for selectively connecting the at least two sensor heads to the spectrometer;
having a control device,
The control device is,
At a timing when one of the at least two sensor heads faces the substrate and the other sensor head does not face the substrate, connection to the spectrometer is established from the one sensor head. Controlling the switcher to initiate a switching process to switch to the other sensor head or from the other sensor head to the one sensor head,
A polishing device characterized in that. According to clause 12,
The other sensor head passes an end of the substrate when moving from a position not facing the substrate to a position facing the substrate,
When starting the switching process, the other sensor head is located near the end,
A polishing device characterized in that. According to clause 12,
Before the one sensor head facing the substrate reaches the end of the trajectory passing under the substrate, switching processing from the one sensor head to the other sensor head not facing the substrate is performed. A polishing device characterized in that the disclosure. According to clause 12,
After the one sensor head facing the substrate passes a point in a trajectory passing under the substrate, switching processing from the other sensor head not facing the substrate to the one sensor head is performed. A polishing device characterized in that the disclosure. According to clause 12,
A polishing apparatus further comprising a rocking device that swings the polishing head on the polishing pad during polishing, and controlling a timing of starting the switching process according to a rocking position of the polishing head. It is a polishing device that polishes a substrate,
a polishing table for holding and supporting a polishing pad;
a polishing head that presses the surface of the substrate against the polishing pad;
a plurality of sensor heads that move across the substrate and detect signals related to the film thickness of the substrate;
One spectrometer that receives and processes signals output from at least two sensor heads among the plurality of sensor heads;
a diverter for selectively connecting the at least two sensor heads to the spectrometer;
having a control device,
The control device is,
At a timing when one of the at least two sensor heads does not face the substrate, the switch device starts a switching process for switching the connection with the spectrometer from the other sensor head to the one sensor head. is controlled, and the switching process is completed after the one sensor head passes a starting point of a trajectory passing under the substrate. According to clause 17,
A polishing apparatus, characterized in that the switching process is started at a timing when the other sensor head is not facing the substrate. According to clause 17,
A polishing apparatus further comprising a rocking device that swings the polishing head on the polishing pad during polishing, and controlling a timing of starting the switching process according to a rocking position of the polishing head. It is a polishing method for polishing a substrate,
The polishing table holds and supports the polishing pad,
The polishing head presses the surface of the substrate against the polishing pad,
A plurality of sensor heads move across the substrate and detect signals related to the film thickness of the substrate,
One spectrometer receives and processes signals output from at least two sensor heads among the plurality of sensor heads,
a diverter selectively connects the at least two sensor heads to the spectrometer,
The control device connects one of the at least two sensor heads to the spectrometer at a timing when one sensor head faces the substrate and the other sensor head does not face the substrate. A polishing method, characterized in that the switcher is controlled to initiate a switching process for switching from a sensor head to the other sensor head, or from the other sensor head to the one sensor head. It is a polishing device that polishes a substrate,
a polishing table for holding and supporting a polishing pad;
a polishing head that presses the surface of the substrate against the polishing pad;
a plurality of sensors that move across the substrate and detect signals related to the film thickness of the substrate;
One signal processing unit that receives and processes signals output from at least two of the plurality of sensors,
a switch for selectively connecting the at least two sensors to the signal processing unit;
having a control device,
The control device is,
At a timing when one of the at least two sensors faces the substrate and the other sensor does not face the substrate, connection with the signal processing unit is established from the one sensor to the other sensor. Controlling the switcher to initiate a switching process to switch to the sensor or from the other sensor to the one sensor,
A polishing device characterized in that. It is a polishing method for polishing a substrate,
The polishing table holds and supports the polishing pad,
The polishing head presses the surface of the substrate against the polishing pad,
A plurality of sensor heads move across the substrate and detect signals related to the film thickness of the substrate,
One spectrometer receives and processes signals output from at least two sensor heads among the plurality of sensor heads,
a diverter selectively connects the at least two sensor heads to the spectrometer,
The control device performs a switching process to switch the connection with the spectroscope from the other sensor head to the one sensor head at a timing when one of the at least two sensor heads does not face the substrate. A polishing method characterized by controlling the switch to start, and controlling the switch to complete the switch process after the one sensor head passes a point of a trajectory passing under the substrate. It is a polishing device that polishes a substrate,
a polishing table for holding and supporting a polishing pad;
a polishing head that presses the surface of the substrate against the polishing pad;
a plurality of sensors that move across the substrate and detect signals related to the film thickness of the substrate;
One signal processing unit that receives and processes signals output from at least two of the plurality of sensors,
a switch for selectively connecting the at least two sensors to the signal processing unit;
having a control device,
The control device initiates a switching process to switch the connection with the signal processing unit from the other sensor to the one sensor at a timing when one of the at least two sensors does not face the substrate. Controlling the switch, and controlling the switch so that the switch process is completed after the one sensor passes a point of a trajectory passing under the substrate,
A polishing device characterized in that.