JP2010284749A - Method and device for polishing substrate while using optical polishing-endpoint detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing method and a polishing device that are suitably used for specifying the cause of photo-corrosion. <P>SOLUTION: The polishing method is carried out as follows. Polishing liquid is supplied onto a polishing pad 22. A substrate W and the polishing pad 22 are brought into sliding contact with each other under the presence of the polishing liquid so as to polish the substrate W. During the polishing of the substrate W, light is irradiated onto the surface of the substrate W while light reflected from the substrate W is received so as to decompose the reflected light in accordance with the wavelength and to measure the intensity of the reflected light over a prescribed wavelength range. The progress of polishing of the substrate W is monitored on the basis of the intensity of the reflected light at least in one prescribed wavelength. The polishing conditions include the time of light irradiation to the substrate W, the intensity of the reflected light in each wavelength within the prescribed wavelength range, and the prescribed wavelength range. The polishing conditions are associated with the time and date when the substrate W is polished so as to store them in a storage device 50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a substrate polishing method and a polishing apparatus using an optical polishing end point detection device, and more particularly to a polishing method and a polishing apparatus that can be suitably used for specifying the cause of photocorrosion of a metal film.

  In a semiconductor device manufacturing process, various materials are repeatedly formed in a film shape on a silicon wafer to form a laminated structure. In order to form this laminated structure, a technique for flattening the surface of the uppermost layer is important. As a means for such planarization, a polishing apparatus that performs chemical mechanical polishing (CMP) is used.

  This type of polishing apparatus generally includes a polishing table that supports a polishing pad, a top ring that holds a substrate (a wafer on which a film is formed), and a polishing liquid supply mechanism that supplies the polishing liquid onto the polishing pad. ing. When polishing the substrate, the substrate is polished by pressing the substrate against the polishing pad with the top ring and moving the top ring and the polishing table relative to each other while supplying the polishing solution onto the polishing pad from the polishing liquid supply mechanism. Then, the film on the substrate is flattened.

FIG. 1 is a cross-sectional view showing a multilayer wiring structure formed on a silicon wafer. An oxide film 100 having a gate structure is formed on the silicon wafer, and a plurality of SiCN films 101 and an oxide film (for example, SiO ₂ ) 102 are formed thereon. The oxide film 102 functions as an interlayer insulating film, and the SiCN film 101 functions as an etch stopper and a diffusion prevention layer for the interlayer insulating film. A trench 103 and a via plug 104 are formed in the oxide film 102. A barrier film (for example, TaN or Ta) 105 is formed on the surface of the trench 103 and the via plug 104 and the upper surface of the oxide film 102. Further, a copper film M2 is formed on the barrier film 105, and the trench 103 and the via plug 104 are filled with a part of the copper film M2. The trench 103 is formed according to a wiring pattern, and copper filled in the trench 103 constitutes a metal wiring. The copper in the trench 103 is electrically connected to the lower copper wiring M <b> 1 through the copper in the via plug 104.

  The copper film M2 formed other than the trench 103 and the via plug 104 is an unnecessary copper film that causes a short circuit between the wirings. This unnecessary copper film is polished by the polishing apparatus described above. The polishing of the copper film M2 is roughly divided into two steps as shown in FIG. The first step is a step of removing the copper film M2 exposed on the surface. In this first step, since only the copper film M2 that is a metal is polished, the progress of the polishing is monitored using an eddy current sensor. The second step is a step of polishing the copper in the trench 103 together with the oxide film 102 after the exposed copper film M2 is removed. Since the height of copper in the trench 103 determines the resistance of the wiring, it is important to accurately detect the polishing end point of the second step.

  As can be seen from FIG. 1, in the second step, the oxide film 102 is mainly polished. Therefore, in the second step, the progress of polishing is monitored using the optical polishing end point detection device. The optical polishing end point detection device irradiates light on the surface of the substrate and determines the polishing end point based on information included in the reflected light from the substrate. An optical polishing end point detection device generally includes a light projecting unit, a light receiving unit, and a spectroscope. The spectroscope decomposes the reflected light from the substrate according to the wavelength and measures the reflection intensity for each wavelength. For example, in the method disclosed in Patent Document 1, a characteristic value is generated by performing a predetermined process for removing a noise component on the intensity (reflection intensity) of reflected light returning from the substrate. The polishing end point is detected from the characteristic point (maximum point or minimum point) of the change.

  As shown in FIG. 2, the characteristic value generated from the reflection intensity periodically changes with the polishing time, and the maximum point and the minimum point appear alternately. This is a phenomenon caused by interference between lights. That is, the light irradiated to the substrate is reflected at the interface between the medium and the film and the interface between the film and the underlying layer of the film, and the lights reflected at these interfaces interfere with each other. The manner of interference of light varies depending on the thickness of the film (that is, the optical path length). For this reason, the intensity of the reflected light returning from the substrate (that is, the reflection intensity) periodically changes according to the thickness of the film. As shown in FIG. 2, the optical polishing end point detection apparatus described above counts the number of characteristic points (maximum points or minimum points) of the change in the characteristic value that appears after the start of polishing, and the number of feature points reaches a predetermined number. The polishing end point is determined based on the time point reached.

The characteristic value is an index (spectral index) obtained based on the reflection intensity for each wavelength. Specifically, it is obtained using the following equation (1).
Characteristic value (Spectral Index) = ref (λ1) / (ref (λ1) + ref (λ2) +.
+ Ref (λk)) (1)
Here, λ represents the wavelength of light, and ref (λk) represents the reflection intensity at the wavelength λk. Note that the number of wavelengths λ of light used for calculating the characteristic value is preferably two or three (that is, k = 2 or 3).

  As can be seen from Equation (1), by dividing the reflection intensity by the reflection intensity, a characteristic value from which the noise component included in the reflection intensity is removed can be obtained. The reflection intensity itself may be monitored instead of the characteristic value. Also in this case, as in the graph of FIG. 2, the reflection intensity periodically changes according to the polishing time, so that the polishing end point can be detected from the change in the reflection intensity.

  As described above, the optical polishing end point detection device is preferably used for polishing a light-transmitting film such as an oxide film, but the optical polishing end point detection device is used for polishing a metal film such as copper. In some cases, photocorrosion may occur. This photocorrosion is a phenomenon in which a photoelectromotive force is generated when light is applied to a material, and an electric current flows through the material by the photoelectromotive force to corrode the material. This photocorrosion changes the resistance of the metal wiring, leading to defects in the semiconductor device as a product. For this reason, preventing photocorrosion is one of the important issues in the manufacturing process of semiconductor devices.

  Photocorrosion is believed to occur easily in the presence of liquid. Since the polishing liquid is used for polishing the substrate, it is important to prevent the occurrence of photocorrosion during the polishing of the substrate. In general, photocorrosion is considered to occur depending on the illuminance (unit: lux) of light. However, there are still many unclear points regarding the detailed conditions when photocorrosion occurs, and as a result, it is difficult to prevent photocorrosion.

Japanese Patent Laid-Open No. 2004-154928

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a polishing method and a polishing apparatus that can be suitably used to identify the cause of photocorrosion.

  In order to achieve the above-described object, according to one embodiment of the present invention, a polishing liquid is supplied onto a polishing pad, and the substrate is polished by bringing the substrate and the polishing pad into sliding contact with each other in the presence of the polishing liquid. During the polishing of the substrate, the surface of the substrate is irradiated with light, the reflected light from the substrate is received, the reflected light is decomposed according to the wavelength, and the intensity of the reflected light over a predetermined wavelength range And monitoring the progress of the polishing of the substrate based on the intensity of the reflected light at at least one predetermined wavelength, the irradiation time of the light on the substrate, and each wavelength within the predetermined wavelength range A polishing method comprising: storing a polishing condition including the intensity of the reflected light and the predetermined wavelength range in a storage device in association with a date and time when the substrate is polished.

In a preferred aspect of the present invention, the polishing conditions further include a type of the polishing liquid.
In a preferred aspect of the present invention, the polishing conditions further include a concentration of the polishing liquid.
In a preferred aspect of the present invention, the polishing condition further includes a type of the light source.
In a preferred aspect of the present invention, the polishing condition further includes a temperature of the substrate.

In a preferred aspect of the present invention, the polishing end point of the substrate is determined based on a change in the intensity of the reflected light at the at least one predetermined wavelength.
In a preferred aspect of the present invention, the integrated irradiation amount is obtained by multiplying the intensity of the reflected light at a predetermined wavelength by the irradiation time of the light, and in a preferable aspect of the present invention, the integrated irradiation amount reaches a predetermined threshold value. It is characterized by issuing a warning when
In a preferred aspect of the present invention, a warning is issued when the light irradiation time reaches a predetermined threshold value.

In a preferred aspect of the present invention, the substrate is swung while the substrate and the polishing pad are in sliding contact with each other.
According to a preferred aspect of the present invention, a notice polishing end point is detected based on the intensity of the reflected light at at least one predetermined wavelength, and the irradiation of the light to the substrate is stopped when the notice polishing end point is detected. The polishing of the substrate is terminated when a predetermined time has elapsed since the detection of the previous polishing end point.
In a preferred aspect of the present invention, the predetermined wavelength range includes visible light, ultraviolet, and infrared wavelength ranges.

  Another aspect of the present invention includes a polishing liquid supply nozzle that supplies a polishing liquid onto a polishing pad, and a relative movement mechanism that polishes the substrate by sliding the substrate and the polishing pad in the presence of the polishing liquid. And a light projecting unit for irradiating light on the surface of the substrate during polishing of the substrate, a light receiving unit for receiving reflected light from the substrate, and decomposing the reflected light according to a wavelength to obtain a predetermined wavelength range. A spectroscope that measures the intensity of the reflected light over a period of time, a monitoring device that monitors the progress of polishing of the substrate based on the intensity of the reflected light at at least one predetermined wavelength, and the light to the substrate A storage device for storing the irradiation time, the intensity of the reflected light at each wavelength within the predetermined wavelength range, and the predetermined wavelength range in association with the date and time when the substrate was polished. A polishing apparatus characterized by the following.

  According to the present invention, polishing conditions such as light irradiation time, light intensity, and light wavelength stored in relation to a polished substrate can be used to investigate the cause of photocorrosion. Furthermore, once the cause of photocorrosion is identified, it is possible to prevent photocorrosion by avoiding the polishing conditions that cause it.

It is sectional drawing which shows the multilayer wiring structure formed on the silicon wafer. It is a graph which shows the characteristic value which changes during grinding | polishing. FIG. 3A is a schematic diagram for explaining the polishing end point detection method used in the present embodiment, and FIG. 3B is a plan view showing the positional relationship between the substrate and the polishing table. It is a graph which shows the spectral waveform acquired when the polishing table is the N-1th rotation, and the spectral waveform acquired when the polishing table is the Nth rotation. It is sectional drawing which shows typically the grinding | polishing apparatus incorporating the grinding | polishing end point detection apparatus. It is a side view which shows the rocking mechanism which rocks a top ring. It is sectional drawing which shows the other modification of the grinding | polishing apparatus shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3A is a schematic diagram for explaining the polishing end point detection method used in the present embodiment, and FIG. 3B is a plan view showing the positional relationship between the substrate and the polishing table. As shown in FIG. 3A, a substrate W to be polished includes a base layer (for example, a silicon layer or a SiN film) and a film formed thereon (for example, light-transmitting SiO ₂ or the like). Insulating film). The light projecting unit 11 and the light receiving unit 12 are arranged to face the surface of the substrate W. During polishing of the substrate W, as shown in FIG. 3B, the polishing table 20 and the substrate W rotate, and a relative movement between a polishing pad (not shown) on the polishing table 20 and the substrate W causes the substrate W to move. The surface is polished.

  The light projecting unit 11 emits light substantially perpendicularly to the surface of the substrate W, and the light receiving unit 12 receives light returning from the substrate W. The light projecting unit 11 and the light receiving unit 12 move across the substrate W every time the polishing table 20 rotates once. At this time, the light projecting unit 11 projects light to a plurality of measurement points including the central portion of the substrate W, and the light receiving unit 12 receives reflected light. A spectroscope 13 is connected to the light receiving unit 12, and the spectroscope 13 measures the intensity of reflected light (that is, the reflection intensity) for each wavelength. More specifically, the spectroscope 13 decomposes the reflected light according to the wavelength, and generates a spectral waveform (spectral profile) representing the reflection intensity for each wavelength over a predetermined wavelength range. A monitoring device 15 is connected to the spectrometer 13, and the spectral waveform is monitored by the monitoring device 15.

  This spectral waveform is acquired every time the polishing table 20 rotates once. Usually, during the polishing of the substrate W, the rotational speed of the polishing table 20 is constant, so that the spectral waveform is acquired at predetermined time intervals determined by the rotational speed of the polishing table 20. The spectral waveform may be acquired every time the polishing table 20 rotates a predetermined number of times (for example, twice or three times).

  In FIG. 3A, the refractive index of the film is n, the refractive index of the medium in contact with the film is n ′, and the refractive index of the underlayer is n ″. The refractive index n of the film is the refractive index n of the medium. If the refractive index n ″ of the underlayer is larger than the refractive index n of the film (n ′ <n <n ″), the light is reflected at the interface between the medium and the film and the interface between the film and the underlayer. The phase of the light is shifted by π with respect to the incident light, and the reflected light from the substrate is light that is reflected by the light reflected at the interface between the medium and the film and the light reflected at the interface between the film and the underlayer. As a result, the intensity of the reflected light changes depending on the phase difference between the two lights, so that the reflection intensity periodically changes according to the change in the thickness of the film (ie, the change in the optical path length).

  FIG. 4 is a graph showing a spectral waveform acquired when the polishing table is in the N-1th rotation and a spectral waveform acquired when the polishing table is in the Nth rotation. In the graph shown in FIG. 4, the horizontal axis represents the wavelength, and the vertical axis represents the reflection intensity. As can be seen from FIG. 4, the spectral waveform is a distribution of reflection intensity according to the wavelength of the reflected light. The spectral waveform acquired during polishing changes as the film thickness decreases. As shown in FIG. 4, the spectral waveform acquired when the polishing table 20 is in the N−1th rotation and the spectral waveform acquired when the polishing table 20 is in the Nth rotation have different shapes as a whole. Have. This indicates that the reflection intensity varies with the film thickness.

  Each time the reflection intensity is measured by the spectrometer 13, the monitoring device 15 calculates a characteristic value (spectral index) from the reflection intensity at one or more predetermined wavelengths using the above equation (1). Further, the monitoring device 15 counts the number of feature points (maximum points or minimum points) of the change in the characteristic value, and determines the polishing end point based on the time point when the number of feature points reaches a predetermined value.

  FIG. 5 is a cross-sectional view schematically showing a polishing apparatus incorporating a polishing end point detection device. As shown in FIG. 5, the polishing apparatus supplies a polishing table 20 that supports the polishing pad 22, a top ring 24 that holds the substrate W and presses against the polishing pad 22, and supplies a polishing liquid (slurry) to the polishing pad 22. The polishing liquid supply nozzle 25 is provided. The polishing table 20 is connected to a motor (not shown) disposed below the polishing table 20 and is rotatable about an 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 top ring 24 is connected to a motor and a lifting cylinder (not shown) via a top ring shaft 28. Thereby, the top ring 24 can be raised and lowered and can be rotated around the top ring shaft 28. The substrate W is held on the lower surface of the top ring 24 by vacuum suction or the like.

  The substrate W held on the lower surface of the top ring 24 is pressed by the top ring 24 against the polishing pad 22 on the rotating polishing table 20 while being rotated by the top ring 24. At this time, the polishing liquid is supplied from the polishing liquid supply nozzle 25 to the polishing surface 22 a of the polishing pad 22, and the surface of the substrate W is polished in a state where the polishing liquid exists between the surface of the substrate W and the polishing pad 22. . In the present embodiment, the relative movement mechanism that causes the substrate W and the polishing pad 22 to slidably contact each other is constituted by the polishing table 20 and the top ring 24.

  The polishing table 20 is formed with a hole 30 that opens on the upper surface thereof. Further, a through hole 31 is formed in the polishing pad 22 at a position corresponding to the hole 30, and the hole 30 and the through hole 31 communicate with each other. The through hole 31 is opened at the polishing surface 22a, and the diameter of the through hole 31 is about 3 to 6 mm. The hole 30 is connected to a liquid supply source 35 via a liquid supply path 33 and a rotary joint 32. During polishing, water (preferably pure water) is supplied from the liquid supply source 35 to the hole 30 as a transparent liquid, fills the space formed by the lower surface of the substrate W and the through hole 31, and the liquid discharge path 34. It is discharged through. The polishing liquid is discharged together with the water, thereby ensuring an optical path of light. The liquid supply path 33 is provided with a valve (not shown) that operates in conjunction 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 through hole 31.

  The polishing apparatus has a polishing end point detection device that detects the polishing end point according to the method described above. The polishing end point detection device includes a light projecting unit 11 that irradiates light on a surface to be polished of a substrate W, an optical fiber 12 that receives light returning from the substrate W, and light received by the optical fiber 12. The characteristic value (see the above formula (1)) is calculated using the spectroscope 13 that decomposes according to the wavelength and measures the reflection intensity for each wavelength over a predetermined wavelength range, and the reflection intensity obtained by the spectroscope 13. And a monitoring device 15 for monitoring the progress of polishing based on the characteristic value.

  The light projecting unit 11 includes a light source 40 and an optical fiber 41 connected to the light source 40. The optical fiber 41 is an optical transmission unit that guides light from the light source 40 to the surface of the substrate W. The optical fiber 41 extends from the light source 40 through the hole 30 to a position near the surface to be polished of the substrate W. The respective tips of the optical fiber 41 and the optical fiber 12 are arranged to face the center of the substrate W held by the top ring 24, and light is applied to a region including the center of the substrate W each time the polishing table 20 rotates. It has become.

  As the light source 40, a light emitting diode (LED), a halogen lamp, a xenon flash lamp, or the like can be used. The optical fiber 41 and the optical fiber 12 are arranged in parallel with each other. The tips of the optical fiber 41 and the optical fiber 12 are arranged substantially perpendicular to the surface of the substrate W, and the optical fiber 41 irradiates light almost perpendicularly to the surface of the substrate W.

  During polishing of the substrate W, light is emitted from the light projecting unit 11 to the substrate W, and reflected light from the substrate W is received by the optical fiber 12 serving as a light receiving unit. While the light is irradiated, water is supplied to the hole 30, whereby the space between the tips of the optical fiber 41 and the optical fiber 12 and the surface of the substrate W is filled with water. The spectroscope 13 measures the intensity of the reflected light for each wavelength, and the monitoring device 15 detects the polishing end point based on the characteristic value as described above. In addition, you may monitor the intensity | strength itself of the reflected light in a predetermined wavelength instead of a characteristic value. Also in this case, as in the graph of FIG. 2, the intensity of the reflected light periodically changes according to the polishing time, so that the polishing end point can be detected from the change in the intensity of the reflected light.

  The monitoring device 15 includes a storage device 50 that stores the irradiation time of light on the substrate, the intensity of light irradiated on the substrate, and the wavelength of light. The intensity of the light applied to the substrate is obtained by measuring the intensity of the reflected light from the substrate with the spectrometer 13. In other words, the intensity of the reflected light obtained for each wavelength by the spectroscope 13 is stored in the storage device 50. The wavelength of light stored in the storage device 50 is a wavelength range that can be measured by the spectrometer 13. The wavelength range that can be measured by the spectroscope 13 is, for example, 400 to 800 nm. The intensity of light measured within this wavelength range is stored in association with the corresponding wavelength.

  Photocorrosion can be related not only to the intensity of light but also to the wavelength of light. Furthermore, not only visible light but also ultraviolet rays and / or infrared rays may affect the occurrence of photocorrosion. From such a viewpoint, the spectroscope 13 measures the intensity of light as energy over a wide wavelength range including visible light, ultraviolet light, and infrared light. By measuring and storing the light intensity over such a wide wavelength range, the relationship between photocorrosion and wavelength can be examined.

  The occurrence of photocorrosion cannot be determined during the polishing of the substrate. After the final manufacturing process, it is possible to determine the occurrence of corrosion only after inspecting whether the device as a product is operating normally. The storage device 50 stores polishing conditions such as light irradiation time, light intensity, and light wavelength in association with the date and time when each substrate is polished. Therefore, when photocorrosion occurs in a certain substrate, it is possible to specify polishing conditions such as the irradiation time of light, the intensity of light, and the wavelength of light stored at the date and time when the substrate is polished.

  In order to prevent photo-corrosion, the monitoring device 15 calculates the integrated irradiation amount by multiplying the intensity of reflected light at a predetermined wavelength by the irradiation time, and when this integrated irradiation amount reaches a predetermined threshold value. It is preferable to issue a warning. Alternatively, a warning may be issued from the monitoring device 15 when the irradiation time reaches a predetermined threshold value.

  The polishing conditions to be stored in the storage device 50 are factors that can cause photocorrosion. For example, the type and concentration of slurry used as the polishing liquid, the temperature of the substrate, ambient light in the polishing chamber, and the like can also cause photocorrosion. Therefore, in addition to the above-described light irradiation time, intensity, and light wavelength, the storage device 50 stores information on the type and concentration of slurry, the temperature of the substrate, and ambient light in the polishing chamber (irradiation time, intensity, wavelength). It is preferable to memorize. The temperature of the substrate can be measured indirectly by measuring the temperature of the polishing surface using a temperature sensor such as a thermography, or by measuring the temperature of water discharged through the liquid discharge path 34.

  The intensity of ambient light in the polishing chamber can be measured by the spectroscope 13 through the light receiving unit 12 when the light receiving unit 12 is not facing the substrate. In this case, the integrated irradiation amount of ambient light may be calculated by multiplying the intensity of ambient light at a predetermined wavelength by the irradiation time. Furthermore, the integrated irradiation amount of the ambient light and the integrated irradiation amount of the light from the light source 40 described above are added, and a warning may be issued when the added integrated irradiation amount reaches a predetermined threshold value.

  As shown in FIG. 3B, the light from the light source 40 is applied to the center of the substrate W every time the polishing table 20 rotates. Therefore, the central portion of the substrate W is the place where photocorrosion is most likely to occur. Therefore, in order to avoid excessive irradiation of light to the center portion of the substrate W, it is preferable to swing the top ring 24 during polishing of the substrate W. FIG. 6 is a side view showing a swing mechanism that swings the top ring 24. As shown in FIG. 6, the swing mechanism includes a swing arm 51 coupled to the top ring shaft 28, a swing shaft 52 that supports the swing arm 51, and a swing shaft 52 around the axis thereof. And a drive mechanism 53 that rotates the angle by the angle. The top ring shaft 28 is connected to one end of the swing arm 51, and the swing shaft 52 is connected to the other end of the swing arm 51. The drive mechanism 53 is composed of, for example, a motor and a reduction gear. By driving the drive mechanism 53, the swing arm 51 swings, whereby the top ring 24 swings. The swinging direction of the top ring 24 is not particularly limited, but it is preferable to swing the polishing ring 20 in the radial direction.

  Instead of swinging the top ring 24 or in addition to swinging the top ring 24, the center of the substrate may be irradiated with light once every time the polishing table 20 rotates a plurality of times. Furthermore, as the light source 40, a halogen lamp that emits steady light and a xenon flash lamp that emits pulsed light may be provided, and a halogen lamp or a xenon flash lamp may be selectively used.

  Photocorrosion generally occurs on the surface of a metal film. Therefore, even if photocorrosion occurs during polishing, the corroded portion is removed by sliding contact with the polishing pad. Therefore, a predetermined notice polishing end point that is slightly earlier than the actual polishing end point is detected, and when the notice polishing end point is detected, irradiation of light from the light source 40 is stopped, and a predetermined time from the notice polishing end point is reached. It is preferable to finish the polishing of the substrate when elapses. The preliminary polishing end point is set to a point slightly earlier than the actual polishing end point in the graph shown in FIG. As described above, by overpolishing the substrate without irradiating the substrate with light, a portion where photocorrosion has occurred can be removed.

  FIG. 7 is a cross-sectional view showing another modification of the polishing apparatus shown in FIG. In the example shown in FIG. 7, a liquid supply path, a liquid discharge path, and a liquid supply source are not provided. Instead, a transparent window 45 is formed in the polishing pad 22. The optical fiber 41 of the light projecting unit 11 irradiates light on the surface of the substrate W on the polishing pad 22 through the transparent window 45, and the optical fiber 12 as the light receiving unit receives reflected light from the substrate W through the transparent window 45. . Other configurations are the same as those of the polishing apparatus shown in FIG.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention should not be limited to the described embodiments, but should be the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 11 Light projection part 12 Light reception part 13 Spectrometer 15 Monitoring apparatus 20 Polishing table 22 Polishing pad 24 Top ring 25 Polishing liquid supply nozzle 28 Top ring shaft 30 Hole 31 Through hole 32 Rotary joint 33 Liquid supply path 34 Liquid discharge path 35 Liquid supply Source 40 Light source 41 Optical fiber 45 Transparent window 50 Storage device 51 Oscillating arm 52 Oscillating shaft 53 Drive mechanism

Claims (22)

Supply the polishing liquid onto the polishing pad,
In the presence of the polishing liquid, the substrate and the polishing pad are brought into sliding contact with each other to polish the substrate,
During polishing of the substrate, the surface of the substrate is irradiated with light,
Receiving reflected light from the substrate;
Decomposing the reflected light according to wavelength, measuring the intensity of the reflected light over a predetermined wavelength range,
Monitoring the progress of polishing of the substrate based on the intensity of the reflected light at at least one predetermined wavelength;
The polishing condition including the irradiation time of the light to the substrate, the intensity of the reflected light at each wavelength within the predetermined wavelength range, and the predetermined wavelength range is associated with the date and time when the substrate is polished. A polishing method characterized by storing the data in a storage device.   The polishing method according to claim 1, wherein the polishing condition further includes a type of the polishing liquid.   The polishing method according to claim 1, wherein the polishing condition further includes a concentration of the polishing liquid.   The polishing method according to claim 1, wherein the polishing condition further includes a type of a light source of the light.   The polishing method according to claim 1, wherein the polishing condition further includes a temperature of the substrate.   The polishing method according to claim 1, wherein a polishing end point of the substrate is determined based on a change in intensity of the reflected light at the at least one predetermined wavelength. Multiplying the intensity of the reflected light at a predetermined wavelength by the irradiation time of the light to obtain an integrated dose,
The polishing method according to claim 1, wherein a warning is issued when the integrated irradiation amount reaches a predetermined threshold value.   The polishing method according to claim 1, wherein a warning is issued when the light irradiation time reaches a predetermined threshold value.   The polishing method according to claim 1, wherein the substrate is swung while the substrate and the polishing pad are in sliding contact with each other. Detecting a noticeable polishing end point based on the intensity of the reflected light at at least one predetermined wavelength;
Stopping the irradiation of the light to the substrate when the preliminary polishing end point is detected,
The polishing method according to claim 1, wherein the polishing of the substrate is terminated when a predetermined time has elapsed since the detection of the preceding polishing end point.   The polishing method according to claim 1, wherein the predetermined wavelength range includes visible light, ultraviolet, and infrared wavelength ranges. A polishing liquid supply nozzle for supplying a polishing liquid onto the polishing pad;
A relative movement mechanism for polishing the substrate by sliding the substrate and the polishing pad in the presence of the polishing liquid;
A light projecting unit for irradiating light on the surface of the substrate during polishing of the substrate;
A light receiving portion for receiving reflected light from the substrate;
A spectroscope that decomposes the reflected light according to a wavelength and measures the intensity of the reflected light over a predetermined wavelength range;
A monitoring device for monitoring the progress of polishing of the substrate based on the intensity of the reflected light at at least one predetermined wavelength;
A storage for storing the irradiation time of the light on the substrate, the intensity of the reflected light at each wavelength within the predetermined wavelength range, and the predetermined wavelength range in association with the date and time when the substrate is polished. And a polishing apparatus.   The polishing apparatus according to claim 12, wherein the polishing condition further includes a type of the polishing liquid.   The polishing apparatus according to claim 12, wherein the polishing condition further includes a concentration of the polishing liquid.   The polishing apparatus according to claim 12, wherein the polishing condition further includes a type of the light source of the light.   The polishing apparatus according to claim 12, wherein the polishing condition further includes a temperature of the substrate.   The polishing apparatus according to claim 12, wherein the monitoring apparatus determines a polishing end point of the substrate based on a change in intensity of the reflected light at the at least one predetermined wavelength. The monitoring device
Multiplying the intensity of the reflected light at a predetermined wavelength by the irradiation time of the light to obtain an integrated dose,
The polishing apparatus according to claim 12, wherein a warning is issued when the integrated irradiation amount reaches a predetermined threshold value.   The polishing apparatus according to claim 12, wherein the monitoring device issues a warning when the irradiation time of the light reaches a predetermined threshold value.   The polishing apparatus according to claim 12, further comprising a swing mechanism that swings the substrate. The monitoring device detects an advance polishing end point based on the intensity of the reflected light at at least one predetermined wavelength;
The light projecting unit stops the irradiation of the light to the substrate when the notice polishing end point is detected,
The polishing apparatus according to claim 12, wherein the relative movement mechanism ends the polishing of the substrate when a predetermined time elapses after detection of the notice polishing end point.   The polishing apparatus according to claim 12, wherein the predetermined wavelength range includes visible light, ultraviolet, and infrared wavelength ranges.

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