JP2011125938A - Polishing method and polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform polishing while monitoring the advancing state of the polishing by measuring the damage amount on a substrate surface simultaneously polishing the substrate surface even in the case of a bare substrate having no film on its surface and consisting of, for example, a reactive semi-conductor single body. <P>SOLUTION: During the polishing, the damage amount on the substrate surface is measured by using at least one of damage amount measuring methods such as the photo-electric type damage amount measuring system, the photo-luminescence light type damage amount measuring system, and the Raman light type damage amount measuring system, and the progress state of the polishing is monitored from the damage reduction on the substrate surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing method and a polishing apparatus, and in particular, while flatly polishing the surface (processed surface) of a substrate such as a single substrate made of SiC or GaN, or a bonded substrate (epitaxial substrate) on which SiC or GaN is mounted. The present invention relates to a polishing method and a polishing apparatus that monitor the progress of polishing and determine the timing of polishing end point (polishing stop or change of polishing conditions).

  Due to the demand for miniaturization of wiring and the increase in the number of layers due to high integration of semiconductor devices in recent years, high flatness of a film surface such as a metal film formed on the surface of a substrate such as a semiconductor wafer is required. For this reason, the surface of the film formed on the substrate surface is generally planarized by removing unevenness by chemical mechanical polishing (CMP). In chemical mechanical polishing, in order to finish polishing at a desired position after performing predetermined polishing, it is necessary to monitor the polishing state of the film during polishing of the film. For this reason, an induced magnetic field is applied to the conductive metal film formed on the substrate surface, the eddy current attenuation generated on the film surface is detected by an eddy current sensor, and the thickness of the metal film is measured. Monitoring is generally performed.

  In addition, the applicants irradiate light on the surface of the film (surface to be polished) formed on the substrate surface, spectrally decompose the reflected light from the surface with a spectroscope, and obtain the film thickness from the obtained spectrum data. It has been proposed to monitor the polishing state by measuring the thickness (see Patent Document 1).

Japanese Patent Laid-Open No. 2004-154928

  For example, in a manufacturing process of a substrate made of a single semiconductor called a bare substrate, a lump of a semiconductor material called an ingot is cut into a substrate and then polished for the purpose of removing damage on the substrate surface. However, in the conventional example, it is possible to monitor the progress of polishing for the purpose of removing the film formed on the substrate surface or flattening the film surface from the measurement principle, but the film such as the bare substrate It is not possible to monitor the progress of the polishing while polishing for the purpose of removing damage on the substrate surface that does not have the substrate.

  The present invention has been made in view of the above circumstances, and measures the amount of damage on the substrate surface at the same time as polishing the substrate surface, even if it is a bare substrate made of a single semiconductor, for example, where no film is formed on the surface. Thus, an object of the present invention is to provide a polishing method and a polishing apparatus that can perform polishing while monitoring the progress of polishing.

  According to the first aspect of the present invention, in the polishing method in which the substrate surface is polished by moving the light-transmitting polishing tool and the substrate surface in contact with each other in the presence of a treatment liquid, the substrate surface is irradiated with excitation light. A photocurrent-type damage measurement method for measuring the amount of damage on the surface of the substrate by measuring the value of the current flowing through the conductor connecting the substrate and the metal wiring provided on the polishing tool, and the surface when the substrate surface is irradiated with excitation light Photoluminescence light damage amount measuring method for measuring the amount of damage on the substrate surface by measuring photoluminescence light emitted from the substrate, and Raman contained in the reflected light from the surface by irradiating the substrate surface with visible monochromatic light Measure the amount of damage on the substrate surface using at least one damage amount measurement method of Raman light type damage amount measurement method that measures the amount of damage on the substrate surface by measuring light, A polishing method characterized by monitoring the progress of polishing from damage reduction amount of the surface.

  In this way, no film is formed on the surface by using at least one damage amount measurement method of the photocurrent damage amount measurement method, the photoluminescence light damage amount measurement method, and the Raman light damage amount measurement method. For example, even a bare substrate made of a single semiconductor can measure the amount of damage on the substrate surface simultaneously with polishing the substrate surface, and monitor the progress of polishing from the amount of damage reduction on the substrate surface.

  The invention according to claim 2 irradiates the substrate surface with excitation light in the presence of the treatment liquid, and simultaneously applies a bias potential to the substrate to form an oxide on the substrate surface. The amount of damage on the surface of the substrate is measured by measuring the photoluminescence light emitted from the surface when the substrate surface is irradiated with excitation light while moving the object and the polishing tool relative to each other and moving them relative to each other to polish and remove the oxide. Photoluminescence light damage measurement method to be measured, and Raman light damage to measure the amount of damage on the substrate surface by irradiating visible monochromatic light on the substrate surface and measuring the Raman light contained in the reflected light from the surface The amount of damage measurement on the substrate surface is measured using at least one of the amount measurement methods, and the progress of polishing is monitored from the amount of damage reduction on the substrate surface. It is a method.

  When polishing the substrate surface while forming an oxide on the substrate surface by applying a bias potential to the substrate, measure at least one of the photoluminescence damage measurement method and the Raman light damage measurement method. By using this method, the amount of damage on the substrate surface can be measured simultaneously with polishing the substrate surface, and the progress of polishing can be monitored from the amount of damage reduction on the substrate surface.

  According to the third aspect of the present invention, in the presence of the treatment liquid, the substrate surface is irradiated with excitation light to form an oxide on the substrate surface, and the oxide formed on the substrate surface and the polishing tool are brought into contact with each other. A photocurrent-type damage measurement method that measures the amount of damage on the substrate surface by measuring the current value flowing in the metal wiring that connects the substrate and the metal wiring provided on the polishing tool while removing the oxide by polishing relative to each other. , Photoluminescence damage measurement method that measures the amount of damage on the substrate surface by measuring the photoluminescence light emitted from the surface when the substrate surface is irradiated with excitation light, and the substrate surface is irradiated with visible monochromatic light And measuring the amount of damage on the substrate surface by measuring the Raman light contained in the reflected light from the surface, using at least one damage amount measurement method of the Raman light type damage amount measurement method. Image quantity measured is the polishing method characterized by monitoring the progress of polishing from damage reduction amount of the substrate surface.

  According to a fourth aspect of the present invention, the substrate is a semiconductor containing a Ga element, and the treatment liquid is a pH buffer solution having a neutral liquidity containing Ga ions. 3. The polishing method according to 3.

  The invention according to claim 5 irradiates the substrate surface with visible monochromatic light while polishing the substrate surface by moving the substrate surface and the polishing tool relative to each other in the presence of the treatment liquid. Measure the amount of damage on the substrate surface by measuring the amount of damage on the surface of the substrate by measuring the Raman light contained in the reflected light from the surface, and measure the amount of damage on the surface of the substrate by polishing the amount of damage reduced on the surface of the substrate. It is a polishing method characterized by monitoring the progress state.

  For example, there may be a case where the substrate surface cannot be polished while irradiating the substrate surface with excitation light or applying a bias voltage to the substrate in consideration of the surface finish such as the polishing rate and flatness. In such a case, the substrate surface is polished by using a Raman light type damage amount measurement method that does not require irradiation of excitation light to the substrate surface or application of a bias voltage to the substrate. At the same time, the amount of damage on the substrate surface can be measured, and the progress of polishing can be monitored from the amount of damage reduction on the substrate surface.

  According to a sixth aspect of the present invention, the treatment liquid is weakly acidic water, water in which air is dissolved, or electrolytic ion water, and a conductive member is provided at a portion that contacts the substrate surface of the polishing tool. 6. The polishing method according to claim 5, wherein:

  The invention according to claim 7 is a container that holds a processing liquid, a light-transmitting polishing tool that is placed in the container soaked in the processing liquid, and a processing liquid in the container that holds a substrate. A substrate holder that is immersed in contact with the polishing tool, a moving mechanism that relatively moves the polishing tool and the substrate held by the substrate holder in contact with each other, and polishing the substrate when the substrate surface is irradiated with excitation light. A photocurrent-type damage amount measuring device that measures the amount of damage on the substrate surface by measuring the current value flowing through the conductive wire connecting the metal wiring provided on the fixture, and the photo emitted from the surface when the substrate surface is irradiated with excitation light Photoluminescence light type damage amount measuring device that measures the amount of damage on the substrate surface by measuring the luminescence light, and measuring the Raman light contained in the reflected light from the surface by irradiating the substrate surface with visible monochromatic light. A polishing apparatus characterized by having at least one damage amount measuring apparatus of the Raman-type damage amount measuring apparatus for measuring the amount of damage substrate surface.

  According to an eighth aspect of the present invention, the optically transparent polishing tool, the substrate holder that holds the substrate in contact with the polishing tool, and the polishing tool and the substrate held by the substrate holder are moved relative to each other while being in contact with each other. A moving mechanism, a processing liquid supply unit for supplying a processing liquid to a contact portion between the polishing tool and the substrate held by the substrate holder, and metal wiring provided on the substrate and the polishing tool when the substrate surface is irradiated with excitation light A photocurrent-type damage amount measuring device that measures the amount of damage on the substrate surface by measuring the value of the current flowing through the lead wire connecting the substrate, and measuring the photoluminescence light emitted from the surface when the substrate surface is irradiated with excitation light Photoluminescence light type damage amount measuring device for measuring the amount of damage on the surface of the substrate, and measuring the Raman light contained in the reflected light from the surface by irradiating the substrate surface with visible monochromatic light. A polishing apparatus characterized by having at least one damage amount measuring apparatus of the Raman-type damage amount measuring device for measuring the over-di amount.

  According to a ninth aspect of the present invention, at least one of a light source for irradiating excitation light onto a substrate surface held by the substrate holder and immersed in the processing liquid in the container and a power source for applying a bias potential to the substrate are provided. The polishing apparatus according to claim 7, wherein the polishing apparatus has a polishing apparatus.

  The invention described in claim 10 is characterized in that the substrate is a semiconductor containing a Ga element, and the processing solution is made of a pH buffer solution containing Ga ions in a neutral range. This is a polishing apparatus.

  According to an eleventh aspect of the present invention, the treatment liquid is water, water in which air is dissolved, or electrolytic ion water, and a conductive member is provided at a portion that contacts the substrate surface of the polishing tool. The polishing apparatus according to claim 7 or 8, wherein the polishing apparatus is characterized in that:

  According to the present invention, a photocurrent-type damage measurement method, a photoluminescence light-type damage measurement method, or a Raman light-type damage measurement is performed even on a bare substrate made of a single semiconductor, for example, with no film formed on the surface. The amount of damage on the substrate surface can be measured simultaneously with the polishing of the substrate surface by the method, and the progress of polishing can be monitored from the amount of damage reduction on the substrate surface.

It is a schematic diagram which shows the concept of a photocurrent type damage amount measuring system. It is a band figure which shows the concept of a photocurrent type damage amount measuring system. It is a graph which shows the relationship between the grinding | polishing time and photocurrent value in a photocurrent type damage amount measuring system. It is a schematic diagram which shows the concept of a photo-luminescence light type damage amount measuring system. It is a band figure which shows the concept of a photo-luminescence light type damage amount measuring system. It is a graph which shows the relationship between the grinding | polishing time and light emission intensity in a photo-luminescence light type damage amount measuring system. It is a schematic diagram which shows the concept of a Raman light type damage amount measuring system. It is a graph which shows the Rayleigh light and the Raman light before and behind grinding | polishing in a Raman light type damage amount measuring system. It is a top view which shows the whole structure of the planarization system provided with the grinding | polishing apparatus of embodiment of this invention. It is sectional drawing which shows the outline | summary of the grinding | polishing apparatus of embodiment of this invention with which the planarization system shown in FIG. 9 is equipped. It is an expanded sectional view which shows the substrate holder of the grinding | polishing apparatus shown in FIG. It is an expanded sectional view which shows the polishing tool of the polishing apparatus shown in FIG. It is an expanded sectional view showing other examples of an abrasive. It is sectional drawing which shows the outline | summary of the grinding | polishing apparatus of other embodiment of this invention with which the planarization system shown in FIG. 9 is equipped. It is an expanded sectional view which shows the polishing tool of the polishing apparatus shown in FIG. It is a graph which shows the excitation light and the photoluminescence light before and behind grinding | polishing in the photoluminescence light type damage amount measuring apparatus with which the grinding | polishing apparatus shown in FIG. 10 is equipped. It is a graph which shows the relationship between the grinding | polishing time and photocurrent when a photocurrent is measured during grinding | polishing with the photocurrent type damage amount measuring apparatus with which the grinding | polishing apparatus shown in FIG. 10 is equipped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First of all, the concept of a photocurrent type damage amount measurement method for measuring the amount of damage on the surface of the substrate by measuring the current value flowing in the conductive wire connecting the substrate and the metal wiring provided on the polishing tool when the substrate surface is irradiated with excitation light. This will be described with reference to the schematic diagram shown in FIG. 1 and the band diagram shown in FIG.

  As shown in FIG. 1, in the presence of a processing liquid (not shown), the light-transmitting polishing tool 10 and the surface (surface to be polished) of a substrate W made of, for example, GaN held by the substrate holder 11 are brought into contact with each other. The surface of the substrate W (for example, the GaN surface) is polished by causing relative movement. During this polishing, the surface of the substrate W is transmitted from the light source 12 through the polishing tool 10 and irradiated with light (excitation light) having energy higher than the band gap of the substrate (for example, GaN) W. The provided metal wiring (not shown) and the substrate W are connected by the conducting wire 13, and the current value flowing along the conducting wire 13 is measured by the ammeter 14.

  In this way, light (excitation light) having energy greater than or equal to the band gap of the substrate W from the light source 12 on the surface of the substrate W, for example, GaN has a band gap of 3.42 eV and a band gap equivalent wavelength of 365 nm. If polishing is performed, for example, when light having a wavelength of 312 nm is irradiated, valence band electrons are excited to the conduction band as shown in FIG. 2, and electron-hole pairs are formed. When the surface damage amount of the substrate W is small, some of the generated electrons are separated from the surface of the substrate W due to the bending of the band on the surface of the substrate W (arrow 1 in FIG. 2), and the conductive wire is used as a photocurrent. It flows along 13. On the other hand, when the surface damage amount of the substrate W is large, the generated electrons move along the damage level formed by the surface damage of the substrate W (arrow 2 in FIG. 2), and further, It disappears by recombining. Thereby, when the surface damage amount of the substrate W is large, the photocurrent value flowing along the conductive wire 13 is small, and as the surface damage amount of the substrate W decreases, the photocurrent value flowing along the conductive wire 13 increases. . Therefore, by measuring this photocurrent value in the polishing step, the surface damage amount of the substrate W can be measured and the progress of polishing can be monitored.

  For example, as polishing progresses and the surface damage amount of the substrate W decreases, the current value flowing through the ammeter 14 increases as shown in FIG. The increase in the flowing current value stops and becomes a constant value. For this reason, the photocurrent value can be measured during polishing, and the time when the increase in the photocurrent value stops and becomes a constant value can be set as the polishing end point.

  Next, the concept of a photoluminescence light damage measurement method for measuring the amount of damage on the substrate surface by measuring the photoluminescence light emitted from the surface when the substrate surface is irradiated with excitation light is shown in FIG. This will be described with reference to the band diagrams shown in FIGS.

  As shown in FIG. 4, in the presence of a processing liquid (not shown), the light-transmitting polishing tool 10 and the surface (surface to be polished) of a substrate W made of, for example, GaN held by the substrate holder 11 are brought into contact with each other. The surface of the substrate W (for example, the GaN surface) is polished by causing relative movement. During this polishing, the surface of the substrate W is irradiated with light (excitation light) having energy equal to or higher than the band gap of the substrate (for example, GaN) W through the polishing tool 10 from the light source 12 to the surface of the substrate W. The photoluminescence light emitted from the substrate is spectrally analyzed by the spectroscope 16 and the intensity corresponding to the wavelength corresponding to the band gap of the substrate W, for example, the wavelength of 365 nm for GaN, is monitored.

  In this way, when the surface of the substrate W is irradiated with light (excitation light) having energy higher than the band gap of the substrate W, band electrons are excited to the conduction band as shown in FIG. Is formed. When the surface damage amount of the substrate W is small, the excited electrons move directly to the valence band, recombine with the holes, and return to the equilibrium state (arrow 1 in FIG. 5). In this process, photoluminescence light having energy corresponding to the band gap is observed. On the other hand, when the surface damage amount of the substrate W is large, the excited electrons move to the valence band via the energy level formed by the disruption of the periodicity of the crystal and recombine with the holes (see FIG. Arrow 2 in 5).

  In this process, the wavelength of the observed photoluminescence light shifts to a longer wavelength side than the wavelength corresponding to the band gap, or becomes non-radiative recombination and the photoluminescence light itself is not observed. That is, when the surface damage amount of the substrate W is large, the wavelength component corresponding to the band gap of the photoluminescence light is small, and the wavelength component corresponding to the band gap of the photoluminescence light is increased as the surface damage amount of the substrate W is reduced. have. For this reason, in the step of polishing, by measuring the intensity of the wavelength corresponding to the band gap of the substrate W of photoluminescence light, the surface damage of the substrate W can be measured and the progress of polishing can be monitored.

  For example, when photoluminescence light emitted from the substrate W is spectrally analyzed by the spectroscope 16 and the intensity of a wavelength (for example, 365 nm) corresponding to the band gap of the substrate W is monitored, polishing proceeds as shown in FIG. The light intensity increases as the surface damage amount of the substrate W decreases, and when the surface damage of the substrate W is removed, the light intensity stops increasing and becomes a constant value. The point in time when the increase in light intensity stops and becomes a constant value can be set as the polishing end point.

  FIG. 7 is a schematic diagram showing the concept of a Raman light type damage amount measurement method for measuring the amount of damage on a substrate surface by irradiating the substrate surface with visible monochromatic light and measuring the Raman light contained in the reflected light from the surface. It explains using.

  As shown in FIG. 7, in the presence of a processing solution (not shown), the light-transmitting polishing tool 10 and the surface (surface to be polished) of a substrate W made of GaN, for example, held by the substrate holder 11 are in contact with each other. The surface of the substrate W (for example, the GaN surface) is polished by causing relative movement. During this polishing, the laser light source 17 transmits the polishing tool 10 to irradiate the surface of the substrate W with visible monochromatic light, and the spectroscope 18 spectrally analyzes the Raman light contained in the reflected light from the surface. To measure.

  When light of an appropriate wavelength is applied to the semiconductor substrate, the reflected light from the surface of the semiconductor substrate is scattered with light having the same wavelength as the applied light (Rayleigh light), as well as light with a slightly shifted wavelength (Raman light). ) Is known to be included. Since the width of this shift depends on the periodicity of the crystal structure, if the amount of damage on the substrate surface is small and the crystal structure is not disturbed, the wavelength shift width must be a value specific to the surface material of the semiconductor substrate. It has been known. When the amount of damage on the substrate surface is large, the wavelength shift width changes due to disorder of the crystal structure. For this reason, by measuring the spectrum of Raman light, the damage on the substrate surface can be measured, and the progress of polishing can be monitored.

  For example, when the surface of the substrate W is irradiated with visible monochromatic light from the laser light source 17 and the reflected light from the surface is subjected to spectrum analysis by the spectroscope 18 during polishing, as shown in FIG. The wavelength and the Rayleigh light having the same half width and the Raman light shifted to the longer wavelength side from the incident light are measured. If the damage on the surface of the substrate W is large, the Raman light spectrum intensity decreases and the half-value width increases, and if the surface damage on the substrate W is small, the Raman light spectrum intensity increases and the half-value width decreases. By monitoring this Raman light spectrum during polishing, the progress of polishing can be monitored, and the point in time when the intensity or half width of the Raman light spectrum does not change can be set as the polishing end point.

  FIG. 9 is a plan view showing the overall configuration of a planarization system including the polishing apparatus according to the embodiment of the present invention. In this flattening system, the surface of a GaN substrate made of GaN alone is polished, and the surface is flattened by removing damage.

  As shown in FIG. 9, this flattening system includes a substantially rectangular housing 1, and the inside of the housing 1 is cleaned with a load / unload unit 2, a polishing unit 3, and a partition by partition walls 1a, 1b, and 1c. It is divided into part 4. The load / unload unit 2, the polishing unit 3 and the cleaning unit 4 are assembled independently and exhausted independently.

  The load / unload unit 2 includes one or more (three in this example) front load units 200 on which substrate cassettes for stocking a large number of substrates (workpieces) are placed. These front load portions 200 are arranged adjacent to each other in the width direction (direction perpendicular to the longitudinal direction) of the planarization system. The front load unit 200 can be equipped with an open cassette, a SMIF (Standard Manufacturing Interface) pod, or a FOUP (Front Opening Unified Pod). Here, SMIF and FOUP are sealed containers that can maintain an environment independent of the external space by accommodating a substrate cassette inside and covering with a partition wall.

  A traveling mechanism 21 is laid along the front load unit 200 in the load / unload unit 2, and a first transport mechanism as a first transport mechanism that can move along the arrangement direction of the substrate cassettes on the traveling mechanism 21. One transfer robot 22 is installed. The first transfer robot 22 can access the substrate cassette mounted on the front load unit 200 by moving on the traveling mechanism 21. The first transfer robot 22 has two hands on the upper and lower sides. For example, the upper hand is used when returning the substrate to the substrate cassette, and the lower hand is used when transferring the unprocessed substrate. By doing so, you can use the upper and lower hands properly.

  A traveling mechanism 21 is laid along the front load unit 200 in the load / unload unit 2, and a first transport mechanism as a first transport mechanism that can move along the arrangement direction of the substrate cassettes on the traveling mechanism 21. One transfer robot 22 is installed. The first transfer robot 22 can access the substrate cassette mounted on the front load unit 200 by moving on the traveling mechanism 21. The first transfer robot 22 has two hands on the upper and lower sides. For example, the upper hand is used when returning the substrate to the substrate cassette, and the lower hand is used when transferring the unprocessed substrate. By doing so, you can use the upper and lower hands properly.

  Since the load / unload unit 2 is an area where it is necessary to maintain the cleanest state, the inside of the load / unload unit 2 has a higher pressure than any of the outside of the apparatus, the polishing unit 3 and the cleaning unit 4. Always maintained. In addition, a filter fan unit (not shown) having a clean air filter such as a HEPA filter or a ULPA filter is provided above the traveling mechanism 21 of the first transfer robot 22. The clean air from which the gas has been removed is constantly blowing downward.

  The polishing unit 3 is a region where the substrate surface (surface to be processed) is removed, and two units according to the first embodiment of the present invention that perform the first stage polishing and the second stage polishing continuously. And two polishing apparatuses 30C and 30D according to the second embodiment of the present invention for performing the third stage polishing. These polishing apparatuses 30A to 30D are arranged along the longitudinal direction of the planarization system.

  As shown in FIG. 10, polishing apparatuses 30 </ b> A and 30 </ b> B according to the first embodiment of the present invention hold a processing liquid 130 containing a Ga ion-containing neutral pH buffer solution. 132. A processing liquid supply nozzle (processing liquid supply unit) 133 that supplies the processing liquid 130 into the container 132 is disposed above the container 132. As the treatment liquid 130, for example, a solution obtained by adding Ga ions having a concentration of 10 ppm or more to a phosphate buffer solution having a pH of 6.86, for example, to bring the Ga ions of the treatment liquid 130 close to saturation. The pH of the pH buffer solution having a neutral liquidity (measured in terms of measurement at room temperature of 25 ° C.) is, for example, 6.0 to 8.0.

  A light transmissive polishing tool 134 is attached to the bottom of the container 132, and when the processing liquid 130 is injected into the container 132, the upper part of the polishing tool 134 is filled with the processing liquid 130. Yes. The polishing tool 134 is made of, for example, quartz glass that is a solid acidic catalyst having excellent light transmittance. As the polishing tool 134, a solid basic catalyst (basic solid catalyst) may be used, or one having an acidic or basic solid catalyst layer only on the surface of the polishing tool 134 may be used.

  The container 132 is connected to the upper end of a rotatable rotating shaft 136, and an opening 132 a that extends in a ring shape around the rotating shaft 136 and is closed by a polishing tool 134 is formed on the bottom plate of the container 132. Has been. A light source 140 that emits excitation light, preferably ultraviolet rays, is disposed immediately below the opening 134a. As a result, the excitation light, preferably ultraviolet rays, radiated from the light source 140 passes through the opening 132a of the container 132, then passes through the inside of the polishing tool 134, and reaches above the polishing tool 134. ing.

  A substrate holder 144 is disposed above the container 132 so that the substrate 142 such as a GaN substrate is detachably held with the surface facing downward. The substrate holder 144 is connected to the lower end of the main shaft 146 that can move up and down and rotate. In this example, a moving mechanism that relatively moves the polishing tool 134 and the substrate (GaN substrate) 142 held by the substrate holder 44 is configured by the rotating shaft 136 that rotates the container 132 and the main shaft 146 that rotates the substrate holder 144. However, either one may be provided.

  Further, in this example, a power source 148 for applying a voltage between the substrate 142 held by the substrate holder 144 and the polishing tool 134 is provided. A switch 150 is interposed in the conducting wire 152a extending from the anode of the power source 148.

  Further, in this example, a so-called immersion type is disclosed in which the processing liquid 130 is filled in the container 132 and the polishing tool 134 and the substrate 142 held by the substrate holder 144 are immersed and processed, but the polishing tool 134 is disclosed. Alternatively, a dropping type processing apparatus may be used in which the processing liquid 130 is supplied to the surfaces of the substrate 142 and the polishing tool 134 by dropping the processing liquid 130 from the processing liquid supply nozzle 133 onto the surface.

  As shown in FIG. 11, the substrate holder 144 has a cover 160 that prevents the processing liquid 130 from entering the inside, and a drive flange 162 connected to the lower end of the main shaft 146 is formed inside the cover 160. The holder body 170 made of metal is connected via a rotation transmission part 168 having a universal joint 164 and a spring 166.

  A retainer ring 172 is disposed around the lower portion of the holder body 170 so as to be movable up and down, and a pressure space 176 can be formed on the lower surface (substrate holding surface) of the holder body 170 between the lower surface and the conductive rubber 174. In addition, a conductive rubber 174 is attached. An air introduction pipe 178 is connected to the pressure space 176 through an air introduction path extending through the holder body 170. Furthermore, a lead electrode 180 is provided on the flange portion of the metal holder main body 170, and a lead wire 152 a extending from the anode of the power source 148 is connected to the lead electrode 180.

  In order to suppress the surface material of the retainer ring 172 from adhering to the surface of the polishing tool 134 due to wear of the surface of the retainer ring 172 at the portion where the retainer ring 172 and the polishing tool 134 are in contact, at least of the surface of the retainer ring 172 The portion that comes into contact with the polishing tool 134 is preferably made of glass such as quartz, sapphire, or zirconia, or ceramics such as alumina, zirconia, or silicon carbide. Examples of the conductive rubber 174 include conductive chloroprene rubber, conductive silicone rubber, and conductive fluororubber.

  As a result, when the back surface of the substrate 142 is held on the lower surface (substrate holding surface) of the holder body 170 of the substrate holder 144 by suction or the like, the back surface of the substrate 142 and the conductive rubber 174 come into contact with each other and the back surface of the substrate 142 is energized. In addition, air is introduced into the pressure space 176 while energization of the back surface of the substrate 142 is maintained, and the substrate 142 can be pressed toward the polishing tool 134.

  With such a configuration, the substrate 142 can be held by the substrate holder 144 while energizing the substrate 142 with simple and low resistance. When the substrate 142 is held by the substrate holder 144 in contact with the conductive rubber 174, it is preferable that polar conductive grease can be filled between the conductive rubber 174 and the substrate 142.

  As shown in FIG. 12, a large number of grooves 134a are provided on the upper surface of the polishing tool 134 at positions corresponding to the openings 132a of the container 132, and a metal film 154 as a metal wiring is formed at the bottom of the large number of grooves 134a. The conductive wire 152b extending from the cathode of the power source 148 is connected to the metal film (metal wiring) 154. The material of the metal film 154 is preferably platinum or gold having corrosion resistance. The grooves 134a provided on the upper surface of the polishing tool 134 are preferably concentric, but may be spiral, radial, or lattice. As shown in FIG. 13, a metal wire 156 made of gold, platinum, or the like may be embedded in the bottoms of many grooves 134 a provided on the upper surface of the polishing tool 134.

  A heater 158 (see FIG. 10) as a temperature control mechanism for controlling the temperature of the substrate 142 held by the holder 144 is embedded in the rotation axis 146 in the substrate holder 144. A heat exchanger as a temperature control mechanism for controlling the processing liquid 130 supplied to the inside of the container 132 to a predetermined temperature is installed in the processing liquid supply nozzle 133 disposed above the container 132 as necessary. Further, a fluid flow path (not shown) as a temperature control mechanism for controlling the temperature of the polishing tool 134 is provided inside the polishing tool 134.

  As is known from the Arrhenius equation, the higher the reaction temperature, the higher the chemical reaction. For this reason, by controlling at least one of the temperatures of the substrate 142, the treatment liquid 130, and the polishing tool 134 to control the reaction temperature, it is possible to improve the stability of the processing speed while changing the processing speed. .

  In the polishing apparatuses 30A and 30B, as shown in FIG. 9, the surface (upper surface) of the polishing tool 134 is conditioned so as to have good flatness and appropriate roughness, for example, a conditioning mechanism (conditioner) 190 including a polishing pad. Is provided. That is, the surface (upper surface) of the polishing tool 134 is conditioned by the conditioning mechanism (conditioner) 190 to have a planar roughness of about 0.1 to 1 μm of PV (Peak-Valley). At this time, a slurry containing abrasive grains is supplied to the surface of the polishing tool 134 as necessary.

  Furthermore, as shown in FIG. 10, the polishing apparatuses 30 </ b> A and 30 </ b> B include a photocurrent type damage amount measuring apparatus 201 with the light source 140 as a part and a photoluminescence light type damage amount with the light source 140 as a part. A measuring device 202 is provided. That is, a conductive wire 152 a that extends from the power source 148 and is connected to the substrate 142 held by the substrate holder 144 and a conductive wire 152 c that extends from the power source 148 and connects to the conductive wire 152 b connected to the metal film (metal wiring) 154 of the polishing tool 134. The photometer type damage amount measuring device 201 is constituted by the ammeter 204 installed in the conducting wire 152c and the light source 140. A switch 206 is interposed in the conducting wire 152c. Further, the photoluminescence light reflected by the surface of the substrate 134 is subjected to spectrum analysis, and the photoluminescence light type damage amount is measured by the spectroscope 208 that measures the intensity of a wavelength (for example, 365 nm) corresponding to the band gap of the substrate W and the light source 140. A measuring device 202 is configured.

  In this example, the light source 140 that irradiates the substrate 142 with excitation light and oxidizes the surface of the substrate 142 is also used as the light source of the photocurrent damage amount measuring apparatus 201 and the photoluminescence damage amount measuring apparatus 202. However, the light sources of the photocurrent damage amount measuring device 201 and the photoluminescence light damage amount measuring device 202 may be provided separately from the light source 140.

  An outline of polishing apparatuses 30C and 30D according to the second embodiment of the present invention is shown in FIG. Differences of the polishing apparatuses 30C and 30D from the polishing apparatuses 30A and 30B are as follows. That is, the polishing apparatuses 30C and 30D are used in the polishing apparatuses 30A and 30B, for example, instead of the treatment liquid 130 in which Ga ions having a concentration of 10 ppm or more are added to a phosphate buffer solution having a pH of 6.86, for example, Weakly acidic water or water 210 dissolved in air is used. Further, a light transmissive polishing tool 212 is used instead of the polishing tool 134 used in the polishing apparatuses 30A and 30B. Further, a laser light source 214 that irradiates visible monochromatic light toward the surface of the substrate 142 held by the substrate holder 144, which is positioned below the container 132, and spectrum analysis of the reflected light from the surface is performed to perform Raman light. And a Raman light type damage amount measuring device 218 having a spectroscope 216 for measuring the intensity of the light.

  The polishing devices 30C and 30D are not provided with the light source 140, the photocurrent damage amount measuring device 201, the photoluminescence light damage amount measuring device 202, and the like, and other configurations are the polishing devices 30A and 30B. Is almost the same.

The pH of the weakly acidic water or water 210 in which air is dissolved is, for example, 3.5 to 6.0, preferably 3.5 to 5.5, and an acid, a pH buffering agent or an oxidizing agent (H ₂ O ₂ , For example, it is manufactured by dissolving CO ₂ gas, air, or the like in pure water or tap water without adding ozone water, persulfate, or the like. In this example, a water supply line (treatment liquid supply unit) 224 is located above the container 132, extends from a pure water supply source (not shown), and has a gas dissolver 220 and a heat exchanger 222 installed therein. Has been placed. As a result, a gas such as CO ₂ gas or air is dissolved in the pure water sent from the pure water supply source by the gas dissolver 220, and the pH is 3.5 to 6, preferably 3.5 to 5. 5 is injected into the container 132, and the temperature of the water 210 injected into the container 132 is adjusted to a predetermined temperature by the heat exchanger 222 as necessary. Note that pure water or tap water having a pH of 3.5 to 6, preferably 3.5 to 5.5 by being left in the atmosphere may be used.

In this way, weakly acidic water having a pH of 3.5 to 6.0 is used without adding an acid, a pH buffering agent, or an oxidizing agent (H ₂ O ₂ , ozone water, persulfate, etc.). As a result, it is possible to perform polishing while preventing the generation of etch pits on the surface (surface to be polished) of the substrate 142 while suppressing a decrease in polishing rate. Instead of the water 210, electrolytic ionic water having a pH of 3.5 to 6.0, preferably a pH of 3.5 to 5.5, or a pH of 8.0 or more may be used.

  As shown in FIG. 15, the polishing tool 212 is arranged on the surface of a base material 250 made of, for example, transparent glass or the like, for example, with a shear A hardness of 50 to 90, at a lattice position on a portion of the surface that contacts the substrate. An elastic body 252 provided with a light-transmitting through hole 252a is laminated, an intermediate layer 254 is formed on the surface of the elastic body 252 by vacuum deposition or the like, and a conductive member is formed on the surface of the intermediate layer 254 by vacuum deposition or the like. 256 is formed. As described above, by providing the conductive member 256 on the surface of the elastic body 252 with the intermediate layer 254 interposed, the conductive member 256 is formed on the surface / surface of the substrate 142 (surface to be polished) with long / single-period irregularities. It can be made to follow easily.

  The elastic body 252 is made of, for example, rubber, resin, foamable resin, or nonwoven fabric, and has a thickness of, for example, 0.5 to 5 mm. In addition, you may make it comprise an elastic body by superimposing the elastic material of two or more layers from which an elasticity modulus differs.

  The intermediate layer 254 has a thickness of 1 to 10 nm, for example, and is interposed between the elastic body 252 and the conductive member 256 to improve the adhesion between the elastic body 252 and the conductive member 256. It is made of, for example, chromium or graphite (SP2 bond) carbon having good adhesion to both of the conductive members 256. In the case where the intermediate layer 254 is formed on the surface of the elastic body 252 by vacuum vapor deposition, it is preferable to use an ion sputtering vapor deposition method in order to suppress expansion and deterioration of the elastic body 252 due to high temperature. The same applies to the case where the conductive member 256 is formed on the surface of the intermediate layer 254 by vacuum deposition.

  The conductive member 256 has a thickness of 100 to 1000 nm, for example. If the thickness is 100 nm or less, the conductive member 256 is worn out by polishing for about 1 hour and is not practical. If the thickness is 1000 nm or more, cracks are generated on the surface of the conductive member 256 during polishing. This is because there is a fear. As the conductive member 256, platinum is preferably used, but other noble metals such as gold, transition metals (Ag, Fe, Ni, Co) that are insoluble or slightly soluble (dissolution rate of 10 nm / h or less) in the water 210. Etc.), graphite, conductive resin, conductive rubber or the like may be used.

  In the polishing apparatuses 30C and 30D, as shown in FIG. 9, the surface (upper surface) of the polishing tool 212 is conditioned so as to have good flatness and appropriate roughness, for example, a conditioning mechanism (conditioner) 190 including a polishing pad. Is provided.

  According to the polishing apparatuses 30C and 30D, while the substrate 142 and the polishing tool 212 held by the substrate holder 144 are immersed in the water 210 or the water 210 is dropped on the upper surface of the polishing tool 212, the surface of the substrate 142 The surface of the substrate 142 can be polished by relatively moving the conductive member 256 such as platinum of the polishing tool 212 in contact with each other.

The polishing mechanism is considered as follows. That is, when the surface of the substrate 142 and the conductive member 256 such as platinum of the polishing tool 212 are moved relative to each other while being in contact with each other, distortion occurs at the contact portion, and the valence band electrons are excited to the conduction band to be -Hole pairs are generated. Next, the electrons excited in the conduction band move to a conductive member 256 such as platinum (having a large work function), and holes remain on the substrate surface. Remaining in the hole in the water 210 of the OH ^- ions or H _{2 O} molecules act, as a result, only the contact portion is oxidized. Then, for example, an oxide of Ga, Al, In is soluble in a weak acid such as a carbon dioxide solution, a weak alkali, or electrolytic ion water, so that the oxide formed in the contact portion is dissolved in the water 210. It is removed from the surface of the substrate 142.

The contact pressure between the surface of the substrate 142 and the conductive member 256 such as platinum of the polishing tool 212 eliminates the warp of the substrate 142, the substrate 142 slips out, or the conductive member 256 of the polishing tool 212 is elastic. to prevent or peeling from 252, for example, it is preferably 0.1~1.0kg / cm ^2, and particularly preferably about 0.4 kg / cm ^2.

  Returning to FIG. 9, between the polishing apparatuses 30A and 30B and the cleaning unit 4, there are four transfer positions along the longitudinal direction (first transfer position TP1, second transfer in order from the load / unload unit 2 side). A first linear transporter 5 is disposed as a second (linear motion) transport mechanism for transporting the substrate between the position TP2, the third transport position TP3, and the fourth transport position TP4). A reversing machine 31 for reversing the substrate received from the first transport robot 22 of the load / unload unit 2 is disposed above the first transport position TP1 of the first linear transporter 5, and below that is disposed. A lifter 32 that can be moved up and down is arranged. Also, a pusher 33 that can be moved up and down below the second transfer position TP2, a pusher 34 that can be moved up and down below the third transfer position TP3, and a pusher 34 that can move up and down below the fourth transfer position TP4. Possible lifters 35 are respectively arranged.

  On the side of the polishing apparatuses 30C and 30D, adjacent to the first linear transporter 5, there are three transfer positions along the longitudinal direction (the fifth transfer position TP5, the sixth transfer position in order from the load / unload unit 2 side). A second linear transporter 6 serving as a second (linear motion) transport mechanism for transporting the substrate between the transport position TP6 and the seventh transport position TP7 is disposed. A lifter 36 that can be moved up and down below the fifth transport position TP5 of the second linear transporter 6, a pusher 37 below the sixth transport position TP6, and a pusher 38 below the seventh transport position TP7. Are arranged respectively. Further, a pure water replacement unit 192 having a ridge and a pure water nozzle is provided between the polishing apparatus 30C and the pusher 37, and a pure water replacement portion 192 having a ridge and a pure water nozzle is also provided between the polishing apparatus 30D and the pusher 38. A water replacement part 194 is arranged.

  As can be understood from the fact that slurry is used during polishing, the polishing portion 3 is the most dirty (dirty) region. Therefore, in this example, exhaust is performed from the periphery of the polishing unit such as a surface plate so that the particles in the polishing unit 3 are not scattered outside, and the pressure inside the polishing unit 3 is adjusted to the outside of the apparatus, Particles are prevented from being scattered by using a negative pressure more than that of the cleaning unit 4 and the load / unload unit 2. Further, usually, an exhaust duct (not shown) is provided below the polishing portion such as a surface plate, and a filter (not shown) is provided above, and the air is cleaned via these exhaust duct and filter. Air is ejected and a downflow is formed.

  The cleaning unit 4 is an area for cleaning a substrate, and includes a second transfer robot 40, a reversing machine 41 for inverting the substrate received from the second transfer robot 40, and three cleaning units 42, 43, 44 for cleaning the substrate. And a dry unit 45 for rinsing the cleaned substrate with pure water and spin-drying, and a third transport unit for transporting the substrate between the reversing machine 41, the cleaning units 42, 43, 44 and the drying unit 45. A robot 46 is provided. The second transfer robot 40, the reversing machine 41, the cleaning units 42 to 44, and the drying unit 45 are arranged in series along the longitudinal direction, and the second transfer robot 40, the reversing machine 41, and the cleaning units 42 to 44 are arranged. And the 3rd conveyance robot 46 is arrange | positioned so that driving | running | working is possible between the drying unit 45 and the 1st linear transporter 5. FIG. A filter fan unit (not shown) having a clean air filter is provided above the cleaning units 42 to 44 and the drying unit 45, and clean air from which particles are removed by this filter fan unit is always below. It is blowing out towards. Further, the inside of the cleaning unit 4 is constantly maintained at a pressure higher than that of the polishing unit 3 in order to prevent inflow of particles from the polishing unit 3.

  The partition 1a surrounding the polishing unit 3 is provided with a shutter 50 positioned between the reversing machine 31 and the first transport robot 22, and when the substrate is transported, the shutter 50 is opened to open the first transport robot. The substrate is transferred between the machine 22 and the reversing machine 31. Further, the partition wall 1b surrounding the polishing unit 3 is provided with a shutter 53 positioned at a position facing the CMP apparatus 30B and a shutter 54 positioned at a position facing the polishing apparatus 30C.

  Next, a process for planarizing the surface of the substrate using the planarization system having such a configuration will be described.

  One substrate is taken out from the substrate cassette mounted on the front load unit 200 by the first transfer robot 22 and transferred to the reversing machine 31. The reversing device 31 reverses the substrate by 180 ° and then places the substrate on the lifter 32 at the first transport position TP1. The second transporter 5 moves laterally and transports the substrate on the lifter 32 to one of the first transport position TP1 and the third transport position TP3. Then, the polishing apparatus 30A receives the substrate from the pusher 32 by the substrate holder 144, and the polishing apparatus 30B receives the substrate from the pusher 34 by the substrate holder 144, and performs the first-stage polishing and the second-stage polishing of the substrate surface. Do.

That is, in the polishing apparatus 30A, the substrate holder 144 holding the substrate 142 such as a GaN substrate is moved upward with the surface (surface to be processed) downward, the substrate holder 144 is lowered, and the substrate 142 is moved to the container. It is immersed in the treatment liquid 130 held inside 132. In this manner, in the state where the processing liquid 130 exists between the substrate 142 and the polishing tool 134, excitation light, preferably ultraviolet rays are emitted from the light source 140, and excitation light, preferably ultraviolet rays, is emitted to the surface (lower surface) of the substrate 142. Irradiate. The wavelength of the excitation light irradiated at this time is equal to or less than the wavelength corresponding to the band gap of the workpiece, and the band gap of GaN is 3.42 eV. Therefore, when processing the GaN substrate, the wavelength is 365 nm or less, for example, 312 nm. Preferably there is. Thereby, when processing a GaN substrate, GaN is oxidized and Ga oxide (Ga ₂ O ₃ ) is generated on the surface of the GaN substrate.

  Note that the polishing may be performed while supplying the processing liquid 130 between the substrate 142 and the polishing tool 134 through the processing liquid supply nozzle (processing liquid supply unit) 133.

At this time, the switch 150 of the power source 148 is turned ON, and a voltage at which the polishing tool 134 becomes a cathode is applied between the polishing tool 134 and the substrate 142 held by the substrate holder 144. Thus, when processing the GaN substrate, the generation of Ga oxide on the surface of the GaN substrate _(Ga 2 _{O 3)} is promoted.

Next, with the excitation light, preferably ultraviolet rays, emitted from the light source 140, and further, with the voltage applied between the polishing tool 134 and the substrate 142, the rotating shaft 136 is rotated to rotate the polishing tool 134. At the same time, the substrate holder 144 is rotated to lower the substrate 142 while rotating, and the surface of the polishing tool 134 is brought into contact with the surface of the substrate 142 at a surface pressure of preferably about 0.01 to 1.0 kgf / cm ² . If the surface pressure is less than 0.01 kgf / cm ² , the warpage of the substrate 142 may be corrected and the entire substrate 142 may not be uniformly polished, and the surface pressure should be 1.0 kgf / cm ² or more. This is because a mechanical defect may occur on the surface of the substrate 142. As a result, the portion that contacts the Ga oxide polishing tool 134 formed on the surface of the substrate 142 such as a GaN substrate, that is, the Ga oxide formed on the tip of the convex portion of the surface of the substrate 142 having the unevenness is selectively selected. The first stage polishing is performed mainly for the purpose of removing the surface damage of the substrate 142. The polishing rate in the first stage polishing is, for example, about 1000 nm / h, and the processing time is, for example, about 5 minutes.

  At the time of this first stage polishing, for example, the spectroscope 208 of the photoluminescence light type damage amount measuring apparatus 202 performs spectrum analysis on the photoluminescence light emitted from the surface of the substrate 134, and a wavelength corresponding to the band gap of the substrate W. For example, in the case of GaN, the intensity of a wavelength of 365 nm is monitored. Then, as shown in FIG. 16, with the progress of polishing, the intensity of photoluminescence light having a wavelength of 365 nm increases. Therefore, the end point of the first stage polishing is detected by detecting that the intensity of the photoluminescence light having a wavelength of 365 nm reaches a predetermined value or becomes constant.

  When the polishing of the first stage is finished, the switch 150 is turned off while the excitation light from the light source 140, preferably ultraviolet rays, continues to be applied, and the voltage application between the polishing tool 134 and the substrate 142 is stopped. Thus, the second stage polishing is performed mainly for the purpose of improving the surface roughness of the substrate 142. The polishing rate in the second stage polishing is, for example, about 200 nm / h, and the processing time is, for example, about 30 minutes. At the time of this second stage polishing, for example, the switch 206 is turned ON, and the current flowing along the conductive wire 152c connecting the substrate 142 and the metal film (metal wiring) 154 of the polishing tool 134 is changed to the photocurrent type damage amount measuring apparatus 201. Measure with the ammeter 204. Then, as shown in FIG. 17, as the polishing progresses, the value of the current flowing through the ammeter 204 gradually increases and eventually becomes substantially constant. Therefore, the end point of the second stage polishing is detected by measuring the value of the current flowing through the ammeter 204 and detecting that the current value reaches a predetermined value or becomes constant.

  After the second stage polishing is completed, the emission of excitation light, preferably ultraviolet rays, from the light source 140 is stopped, the substrate holder 144 is raised, and then the rotation of the substrate 142 is stopped. The substrate surface is rinsed with pure water as necessary, and then transferred to the pusher 33 at the second transport position TP2. The first transporter 5 transports the substrate on the pusher 33 to the lifter 35. Similarly, in the polishing apparatus 30B, the substrate holder 144 receives the substrate 142 from the pusher 34, performs the first stage polishing and the second stage polishing, and then transfers the polished substrate 142 to the fourth transport. Delivered to the lifter 35 at position TP4.

  The second transfer robot 40 receives the substrate from the lifter 35 and places it on the lifter 36 at the fifth transfer position TP5. The second transporter 6 moves laterally and transports the substrate on the lifter 36 to one of the sixth transport position TP6 or the seventh transport position TP7.

The polishing apparatus 30C receives the substrate from the pusher 37 by the substrate holder 144 and performs the third stage polishing. That is, the substrate holder 144 holding the substrate 142 such as a GaN substrate with the surface (surface to be processed) facing downward is moved above the container 132, and the substrate holder 144 is lowered while rotating, so that the substrate 142 is moved to the container 132. For example, 100-1000 hPa (0.1-1.0 kgf / cm ² ) is applied to the conductive member 256 such as platinum of the rotating polishing tool 212 by being immersed in the water 210 held inside and further lowered. The surface of the substrate 142 is preferably brought into contact with the contact pressure (pressing force) of about 400 hPa (0.4 kgf / cm ² ). In this way, in the state where the water 210 exists between the substrate 142 and the polishing tool 212, the surface of the substrate 142 and the conductive member 256 such as platinum of the polishing tool 212 are moved relative to each other while being in contact with each other. A third stage of polishing for the purpose of finishing the surface of the substrate is performed, for example, for 180 minutes. The third stage of polishing may be performed while supplying water 210 between the conductive member 256 such as platinum of the polishing tool 212 and the surface of the substrate 142 through the water supply line 224.

  During this third stage of polishing, visible monochromatic light is emitted from the laser light source 214 of the Raman light type damage measuring device 218 toward the surface of the substrate 142 held by the substrate holder 144 and the elastic body. The light is transmitted through a through-hole 252a for light transmission provided in 252 and irradiated, and the reflected light from the surface is spectrally analyzed by a spectroscope 216 to measure the intensity of Raman light. That is, as described above, as the polishing progresses, the intensity of Raman light increases as shown in FIG. Therefore, the end point of the third stage polishing is detected by detecting that the intensity of the Raman light reaches a predetermined value or becomes constant.

  After finishing the third stage of polishing, the water 210 remaining on the substrate surface is replaced with pure water by the pure water replacement unit 192 and returned to the sixth transport position TP6. Similarly, even in the polishing apparatus 30D, the substrate holder 144 receives the substrate 142 from the pusher 38, performs the third stage polishing (surface finish polishing), and purifies the water 210 remaining on the substrate surface after the polishing process. The water replacement unit 194 replaces with pure water and returns to the seventh transport position TP7. Thereafter, the substrate after the replacement with pure water is moved to the fifth transport position TP5 by moving the second transporter 6 laterally.

  The second transfer robot 40 takes out the substrate from the fifth transfer position TP5 and transfers it to the reversing machine 41. The reversing machine 41 reverses the substrate by 180 ° and then transports the substrate to the first cleaning unit. The third transport unit 46 transports the substrate from the first cleaning unit 42 to the second cleaning unit 43, where the substrate is cleaned.

  Then, the third transport robot 46 transports the cleaned substrate to the third cleaning unit 44, where the substrate is cleaned with pure water, and then transported to the drying unit 45, where the substrate is rinsed with pure water. After that, spin dry by rotating at high speed. The first transfer robot 22 receives the substrate after spin drying from the drying unit 45 and returns it to the substrate cassette mounted on the front load unit 200.

  In the above example, the end point of the first stage polishing is detected by the photoluminescence light damage measuring device 202, but it is detected by the Raman light damage measuring device 218 shown in FIG. For example, the average value may be detected by combining both.

  Further, although the end point of the second stage polishing is detected by the photocurrent damage measuring device 200, the photoluminescence damage measuring device 202 or the Raman light damage measuring device 218 shown in FIG. On the other hand, it may be detected, or two or more damage measuring devices may be combined to detect, for example, an average value. In the first stage and second stage polishing, processing using a pH buffer solution in a neutral region containing Ga ions is performed. However, the end point detection of the present invention is not limited to this processing method.

  Furthermore, since SiC and GaN transmit visible light, the substrate thickness can be measured from the interference of the reflected light on the front and back of the substrate by irradiating the substrate with visible light. A film thickness measuring device using this optical interference method and the above-described method for monitoring the progress of polishing may be combined and used in a complementary manner.

DESCRIPTION OF SYMBOLS 3 Polishing part 10 Polishing tool 11 Substrate holder 12 Light source 13 Conductor 14 Ammeter 16 Spectrometer 17 Laser light source 18 Spectrometer 30A, 30B, 30C, 30D Polishing apparatus 130 Processing liquid 132 Container 133 Processing liquid supply nozzle (processing liquid supply part)
134 Polishing tool 136 Rotating shaft 140 Light source 142 GaN substrate 144 Substrate holder 146 Main shaft 154 Metal film (metal wiring)
201 Photocurrent damage amount measuring device 202 Photoluminescence light damage amount measuring device 204 Ammeter 208 Spectrometer 210 Treatment liquid (water)
212 Polishing tool 214 Laser light source 216 Spectrometer 218 Raman light type damage amount measuring device 224 Water supply line (treatment liquid supply unit)
256 Conductive member

Claims (11)

In a polishing method for polishing a substrate surface by causing relative movement while bringing a light-transmitting polishing tool and a substrate surface into contact with each other in the presence of a treatment liquid,
Photocurrent damage measurement method that measures the amount of damage on the substrate surface by measuring the current value that flows through the conductor that connects the substrate and the metal wiring provided on the polishing tool when the substrate surface is irradiated with excitation light, excited on the substrate surface The photoluminescence light type damage amount measuring method for measuring the amount of damage on the substrate surface by measuring the photoluminescence light emitted from the surface when irradiated with light, and the surface of the substrate irradiated with visible monochromatic light from the surface The amount of damage on the substrate surface is measured using at least one damage amount measurement method of the Raman light type damage amount measurement method for measuring the amount of damage on the substrate surface by measuring the Raman light contained in the reflected light of the substrate surface, A polishing method characterized by monitoring the progress of polishing from the amount of damage reduction. In the presence of the treatment liquid, the substrate surface is irradiated with excitation light, and simultaneously a bias potential is applied to the substrate to form an oxide on the substrate surface. The oxide formed on the substrate surface and the polishing tool are brought into contact with each other. While removing the oxide by relative movement,
Photoluminescence light damage measurement method that measures the amount of damage on the substrate surface by measuring the photoluminescence light emitted from the surface when the substrate surface is irradiated with excitation light, and the substrate surface is irradiated with visible monochromatic light The amount of damage on the substrate surface is measured using at least one damage amount measurement method of the Raman light type damage amount measurement method that measures the amount of damage on the substrate surface by measuring the Raman light contained in the reflected light from the surface. A polishing method characterized by monitoring the progress of polishing from the amount of damage reduction on the substrate surface. In the presence of the treatment liquid, the substrate surface is irradiated with excitation light to form an oxide on the substrate surface, and the oxide formed on the substrate surface and the polishing tool are brought into contact with each other and moved relative to each other to polish the oxide. While removing
A photocurrent type damage amount measuring method for measuring the amount of damage on the substrate surface by measuring the current value flowing in the metal wiring connecting the substrate and the metal wiring provided on the polishing tool, from the surface when the substrate surface is irradiated with excitation light Photoluminescence light type damage amount measurement method for measuring the amount of damage on the substrate surface by measuring the emitted photoluminescence light, and Raman light contained in the reflected light from the surface by irradiating the substrate surface with visible monochromatic light The amount of damage on the substrate surface is measured to measure the amount of damage on the substrate surface using at least one damage amount measurement method of the Raman light type damage amount measurement method, and the progress of polishing from the amount of damage reduction on the substrate surface A polishing method characterized by monitoring a state.   4. The polishing method according to claim 2, wherein the substrate is a semiconductor containing a Ga element, and the treatment liquid is a pH buffer solution containing Ga ions in a neutral range. In the presence of the processing liquid, while polishing the substrate surface by moving the substrate surface and the polishing tool relative to each other while contacting each other,
The amount of damage on the surface of the substrate is measured using a Raman light type damage amount measuring method in which the amount of damage on the surface of the substrate is measured by irradiating the substrate surface with visible monochromatic light and measuring the Raman light contained in the reflected light from the surface. A polishing method characterized by measuring and monitoring the progress of polishing from the amount of damage reduction on the substrate surface.   The treatment liquid is weakly acidic water, water in which air is dissolved, or electrolytic ion water, and a conductive member is provided on a portion of the polishing tool that contacts the substrate surface. 5. The polishing method according to 5. A container for holding the treatment liquid;
A light transmissive polishing tool disposed in the container soaked in the treatment liquid;
A substrate holder that holds the substrate and is immersed in the processing solution in the container to contact the polishing tool;
A moving mechanism for relatively moving the polishing tool and the substrate held by the substrate holder while contacting each other;
Photocurrent-type damage measuring device that measures the amount of damage on the substrate surface by measuring the current value that flows through the conductor that connects the substrate and the metal wiring provided on the polishing tool when the substrate surface is irradiated with excitation light, excited on the substrate surface Photoluminescence light type damage amount measuring device for measuring the amount of damage on the substrate surface by measuring photoluminescence light emitted from the surface when irradiated with light, and visible monochromatic light on the substrate surface from the surface A polishing apparatus comprising at least one damage amount measuring device of a Raman light type damage amount measuring device that measures the amount of damage on a substrate surface by measuring Raman light contained in the reflected light. A light transmissive polishing tool;
A substrate holder for holding the substrate and contacting the polishing tool;
A moving mechanism for relatively moving the polishing tool and the substrate held by the substrate holder while contacting each other;
A treatment liquid supply unit for supplying a treatment liquid to a contact portion between the polishing tool and the substrate held by the substrate holder;
Photocurrent-type damage measuring device that measures the amount of damage on the substrate surface by measuring the current value that flows through the conductor that connects the substrate and the metal wiring provided on the polishing tool when the substrate surface is irradiated with excitation light, excited on the substrate surface Photoluminescence light type damage amount measuring device for measuring the amount of damage on the substrate surface by measuring photoluminescence light emitted from the surface when irradiated with light, and visible monochromatic light on the substrate surface from the surface A polishing apparatus comprising at least one damage amount measuring device of a Raman light type damage amount measuring device that measures the amount of damage on a substrate surface by measuring Raman light contained in the reflected light.   8. The apparatus according to claim 7, further comprising at least one of a light source for irradiating excitation light onto a substrate surface held by the substrate holder and immersed in the processing liquid in the container and a power source for applying a bias potential to the substrate. Or the polishing apparatus of 8.   10. The polishing apparatus according to claim 9, wherein the substrate is a semiconductor containing a Ga element, and the treatment liquid is a pH buffer solution containing Ga ions in a neutral range.   9. The treatment liquid is water, water in which air is dissolved, or electrolytic ion water, and a conductive member is provided at a portion of the polishing tool that contacts the substrate surface. Polishing equipment.

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