WO2022158284A1 - 研磨パッドの表面性状測定装置、研磨パッドの表面性状測定方法、および研磨パッドの表面性状判定方法 - Google Patents
研磨パッドの表面性状測定装置、研磨パッドの表面性状測定方法、および研磨パッドの表面性状判定方法 Download PDFInfo
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- WO2022158284A1 WO2022158284A1 PCT/JP2022/000075 JP2022000075W WO2022158284A1 WO 2022158284 A1 WO2022158284 A1 WO 2022158284A1 JP 2022000075 W JP2022000075 W JP 2022000075W WO 2022158284 A1 WO2022158284 A1 WO 2022158284A1
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- polishing pad
- light
- polishing
- surface texture
- wavelength composition
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/005—Control means for lapping machines or devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/12—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving optical means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/11—Lapping tools
- B24B37/20—Lapping pads for working plane surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
- B24B49/18—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation taking regard of the presence of dressing tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67092—Apparatus for mechanical treatment
Definitions
- the present invention relates to a polishing pad surface texture measuring apparatus, a polishing pad surface texture measuring method, and a polishing pad surface texture determining method used for polishing a substrate such as a semiconductor wafer.
- step coverage worsens. Therefore, in order to achieve multi-layer wiring, the step coverage must be improved and planarization processing must be performed in a proper process. Further, since the depth of focus becomes shallower as the optical lithography becomes finer, it is necessary to planarize the surface of the semiconductor device so that the unevenness of the surface of the semiconductor device is kept below the depth of focus.
- CMP chemical mechanical polishing
- a polishing apparatus is used to polish a substrate such as a semiconductor wafer by slidingly contacting the polishing pad while supplying a polishing liquid to the polishing pad.
- the polishing liquid is, for example, slurry containing abrasive grains such as silica (SiO 2 ) and ceria (CeO 2 ).
- a polishing apparatus for performing CMP (Chemical Mechanical Polishing) described above includes a polishing table having a polishing pad and a substrate holding device called a polishing head or the like for holding a semiconductor wafer (substrate). Such a polishing apparatus is used to polish an insulating film, a metal film, or the like on a substrate by pressing the substrate against a polishing pad with a predetermined pressure while holding the substrate by a substrate holding device. ing.
- CMP Chemical Mechanical Polishing
- polishing pad When the substrate is polished, abrasive grains and polishing dust adhere to the surface of the polishing pad, and the surface shape and condition of the polishing pad change, degrading the polishing performance. Therefore, as the polishing of the substrate is repeated, the polishing speed decreases and polishing unevenness occurs. Therefore, in order to reproduce the surface shape and condition of the deteriorated polishing pad, dressing (conditioning) of the polishing pad is performed using a dresser.
- the surface shape and condition of the polishing pad that is, the surface texture of the polishing pad, is one of the factors that determine CMP performance. Therefore, it is desirable to directly measure the surface properties of the polishing pad and reflect the measured values in the dressing conditions. Therefore, in a conventional polishing apparatus, a device for directly measuring the surface properties of the polishing pad is used to determine the dressing conditions.
- a surface texture measuring apparatus an apparatus for measuring the surface texture of a polishing pad.
- an object of the present invention is to provide a polishing pad surface texture measuring apparatus and a polishing pad surface texture measuring method that can improve the accuracy of measuring the surface texture of a polishing pad.
- a further object of the present invention is to provide a method capable of accurately determining the surface properties of a polishing pad.
- a surface texture measuring apparatus for a polishing pad used for polishing a substrate, wherein the polishing pad is irradiated with light from a plurality of directions when the polishing pad is viewed from the polishing surface side of the polishing pad. and a light receiving unit capable of receiving reflected light from a plurality of directions reflected by the surface of the polishing pad.
- the surface texture measuring apparatus further includes an irradiation direction changing mechanism that changes the irradiation direction of the light.
- the irradiation direction changing mechanism includes a rotary motor that rotates the light projecting section and the light receiving section, and a shaft coupled to the rotary motor.
- the light projecting section includes a plurality of light sources arranged facing different directions
- the light receiving section includes a plurality of light receiving elements arranged facing different directions.
- the surface texture measuring apparatus further includes a data processing section electrically connected to the light receiving section, and the data processing section receives a plurality of lights irradiated onto the polishing pad from a plurality of directions different from each other. The intensity distribution of a plurality of reflected lights from the polishing pad is used to acquire an index value that indirectly indicates the surface properties of the polishing pad.
- a polishing pad is irradiated with light from a plurality of irradiation directions different from each other, a plurality of reflected lights from the polishing pad corresponding to each of the plurality of lights irradiated to the polishing pad are received, and a plurality of reflected lights are received.
- a method for measuring the surface texture of a polishing pad is provided, which is the direction when viewed from the polishing surface side of the polishing pad.
- the polishing pad is irradiated with light from a plurality of irradiation directions different from each other, and the plurality of reflected lights from the polishing pad corresponding to each of the plurality of lights irradiated to the polishing pad are received.
- the step includes irradiating the polishing pad with the light while changing the irradiation direction of the light, and receiving each reflected light from the polishing pad of the light in each irradiation direction.
- the polishing pad is irradiated with light from a plurality of irradiation directions different from each other, and the plurality of reflected lights from the polishing pad corresponding to each of the plurality of lights irradiated to the polishing pad are received.
- the step includes irradiating the polishing pad with light from a plurality of irradiation directions using a plurality of light sources, and transmitting a plurality of reflected lights from the polishing pad corresponding to the plurality of lights irradiated to the polishing pad to a plurality of light receiving elements. receiving light at.
- a method for determining the surface properties of a polishing pad is provided, wherein the obtaining step includes the step of irradiating the surface of the polishing pad with a laser beam and receiving reflected light from the polishing pad.
- the step of calculating a wavelength composition ratio that indirectly indicates the surface properties of the polishing pad from the plurality of intensity distributions obtained at the plurality of locations includes calculating the wavelength composition ratio from each of the plurality of intensity distributions. and calculating a plurality of wavelength composition ratios. In one aspect, the step of calculating a wavelength composition ratio that indirectly indicates the surface properties of the polishing pad from the plurality of intensity distributions obtained at the plurality of locations includes averaging the plurality of intensity distributions, and averaging the plurality of intensity distributions. and calculating the wavelength composition ratio from the intensity distribution of the reflected light.
- the step of determining whether the surface texture of the polishing pad is good or bad based on the calculated wavelength composition ratios includes determining whether the plurality of calculated wavelength composition ratios are within a predetermined reference range. and determining that the surface properties of the polishing pad are good when all of the calculated plurality of wavelength composition ratios are within a predetermined reference range.
- the step of determining whether the surface texture of the polishing pad is good or bad based on the calculated wavelength composition ratios includes calculating an average value of the plurality of calculated wavelength composition ratios, comparing a predetermined threshold value and confirming whether or not the calculated plurality of wavelength composition ratios are within a predetermined reference range, the average value being smaller than the threshold value, and determining that the surface properties of the polishing pad are good when all of the calculated plurality of wavelength composition ratios are within the reference range.
- the step of determining whether the surface texture of the polishing pad is good or bad based on the calculated wavelength composition ratios includes calculating an average value of the plurality of calculated wavelength composition ratios, comparing a predetermined threshold value and confirming whether or not the calculated plurality of wavelength composition ratios are within a predetermined reference range, the average value being greater than the threshold value, and determining that the surface properties of the polishing pad are good when all of the calculated plurality of wavelength composition ratios are within the reference range.
- the method further includes the step of terminating the break-in of the polishing pad when it is determined that the surface properties of the polishing pad are good.
- the present invention it is possible to acquire intensity distributions of a plurality of reflected lights from the polishing pad of a plurality of lights irradiated to the polishing pad from a plurality of directions different from each other. As a result, it is possible to improve the measurement accuracy of the surface texture of the polishing pad. Furthermore, according to the present invention, by acquiring the intensity distribution of the reflected light from the polishing pad at a plurality of points on the surface of the polishing pad, it is possible to evaluate the surface properties of the polishing pad including in-plane variations. Thereby, the surface properties of the polishing pad can be determined with high accuracy.
- FIG. 1 is a schematic diagram showing an embodiment of a polishing apparatus equipped with a polishing pad surface texture measuring device; 1 is a schematic diagram showing an embodiment of an internal structure (measurement structure) of a measurement head; FIG. FIG. 4 is a schematic diagram showing another embodiment of the internal structure of the measuring head; It is a figure explaining the reflected light from a polishing pad.
- FIG. 4 is a schematic diagram showing the spatial wavelength spectrum of the surface of the polishing pad;
- FIG. 4 is a perspective view schematically showing one embodiment in which the measuring head is arranged at the measuring position;
- FIG. 7A is a front view of the measuring head.
- FIG. 7B is a bottom view of the measuring head.
- FIG. 7 is a schematic diagram showing an enlarged periphery of the measuring head shown in FIG. 6.
- FIG. 4 is a flow chart showing an embodiment of a surface texture determination method;
- FIG. 4 is a diagram showing an example of multiple measurement points on the surface of a polishing pad;
- 4 is a graph showing an example of a wavelength composition ratio for each processing condition of a polishing pad during break-in.
- FIG. 12A is a diagram comparing the wavelength composition ratio under condition 1 in FIG. 11 with a predetermined reference range and a predetermined threshold.
- FIG. 12B is a diagram comparing the wavelength composition ratio under condition 6 in FIG. 11 with a predetermined reference range and a predetermined threshold.
- FIG. 12C is a diagram comparing the wavelength composition ratio under condition 10 in FIG.
- FIG. 11 is a flow chart showing another embodiment of a surface texture determination method
- FIG. 10 is a diagram showing the result of measuring the surface properties of the polishing pad 2 after dressing under predetermined dressing conditions while polishing the substrate W, and calculating the wavelength composition ratio.
- FIG. 4 is a schematic diagram showing another embodiment of the surface texture measuring device;
- FIG. 10 is a diagram showing a state when the light projecting section and the light receiving section are rotated about their axes; 4 is a flow chart showing an embodiment of a polishing pad surface texture measuring method.
- 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 0°; 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 45°; 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 90°.
- FIG. 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 135°; 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 180°; 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 225°; 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 270°; 4 is a graph showing the intensity distribution of reflected light from the polishing pad when the irradiation angle is 315°; FIG. 3 is a schematic diagram showing still another embodiment of the surface texture measuring device; 27 is a top view of the measuring head shown in FIG. 26; FIG.
- FIG. 1 is a schematic diagram showing an embodiment of a polishing apparatus equipped with a polishing pad surface texture measuring apparatus.
- a polishing apparatus CMP apparatus holds a polishing table 1 supporting a polishing pad 2, and a substrate W such as a semiconductor wafer, which is an object to be polished, and presses it against the polishing pad on the polishing table.
- a polishing head 10 a dressing device 20 for dressing the polishing pad 2, a polishing pad surface property measuring device 30 for measuring surface properties such as the surface shape and surface state of the polishing pad 2, and operations of each component of the polishing device. and an operation control unit 9 for controlling the
- the polishing table 1 is connected through a table shaft 4 to a table rotation motor 3 arranged below it, and is rotatable around the axis AX1 of the table shaft 4.
- a polishing pad 2 is attached to the upper surface of the polishing table 1, and the surface of the polishing pad 2 constitutes a polishing surface 2a on which the substrate W is polished.
- the polishing pad 2 is attached on the polishing table 1 so that its center O is on the axis AX1.
- a polishing liquid supply nozzle (not shown) is installed above the polishing table 1, and the polishing liquid (slurry) is supplied to the polishing pad 2 on the polishing table 1 by the polishing liquid supply nozzle. .
- the polishing head 10 is connected to a polishing head shaft 11, and the polishing head shaft 11 is vertically moved with respect to the polishing head swing arm 12 by an elevating mechanism (not shown).
- the lifting mechanism is connected to the polishing head swing arm 12 .
- the polishing head shaft 11 is rotated by driving a polishing head rotating motor (not shown), and the polishing head 10 rotates around the axis of the polishing head shaft 11 .
- the polishing head rotation motor is located within the polishing head swing arm 12 .
- the polishing head 10 can hold a substrate W such as a semiconductor wafer on its lower surface.
- the polishing head swing arm 12 is configured to be rotatable, and the polishing head 10 holding the substrate W on its lower surface can be moved from the substrate receiving position to above the polishing table 1 by turning the polishing head swing arm 12 . It's becoming The polishing head 10 holds the substrate W on its lower surface and presses the substrate W against the surface of the polishing pad 2 (polishing surface 2a). At this time, the polishing table 1 and the polishing head 10 are rotated, and polishing liquid (slurry) is supplied onto the polishing pad 2 from a polishing liquid supply nozzle (not shown) provided above the polishing table 1 .
- a polishing liquid containing silica (SiO 2 ) or ceria (CeO 2 ) as abrasive grains is used as the polishing liquid.
- SiO 2 can be used as the insulating film.
- a Cu film, a W film, a Ta film, and a Ti film can be used as the metal film.
- the dressing device 20 includes a dresser 22 that slides on the polishing surface 2 a of the polishing pad 2 , a dresser shaft 24 that is connected to the dresser 22 , an air cylinder 23 provided at the upper end of the dresser shaft 24 , and the dresser shaft 24 . and a dresser arm 21 that is rotatably supported.
- the lower part of the dresser 22 is composed of a dressing member 22a.
- the dressing member 22a has a circular dressing surface, and hard particles are fixed to the dressing surface by electrodeposition or the like. Examples of hard particles include diamond particles and ceramic particles.
- a dresser rotation motor (not shown) is arranged in the dresser arm 21 .
- the dresser shaft 24 is driven by the dresser rotation motor, and the dresser shaft 24 rotates around the axis of the dresser shaft 24 .
- the air cylinder 23 vertically moves the dresser shaft 24 and the dresser 22 integrally to press the dressing member 22a against the polishing surface 2a of the polishing pad 2 with a predetermined pressing force.
- the air cylinder 23 is connected to a gas supply source (not shown) and is a device that applies a dressing load to the polishing pad 2 to the dresser 22 .
- the dressing load can be adjusted by air pressure supplied to the air cylinder 23 .
- the air cylinder 23 can separate the dresser 22 from the polishing surface 2 a of the polishing pad 2 .
- the air cylinder 23 functions as an elevation actuator that vertically moves the dresser shaft 24 and the dresser 22 with respect to the dresser arm 21 .
- a combination of a servomotor and a ball screw mechanism may be used as a lift actuator that moves the dresser shaft 24 and dresser 22 up and down relative to the dresser arm 21 .
- the dressing device 20 further includes a spindle 26 connected to the dresser arm 21 and a spindle rotation motor (rotation actuator) 27 that rotates the spindle 26 .
- a spindle rotation motor rotation actuator
- the dressing of the polishing surface 2a of the polishing pad 2 is performed as follows.
- a polishing table 1 and a polishing pad 2 are rotated by a table rotating motor 3, and a dressing liquid (for example, pure water) is supplied to the polishing surface 2a of the polishing pad 2 from a dressing liquid supply nozzle (not shown).
- a dressing liquid for example, pure water
- the dresser 22 is rotated around the axis of the dresser shaft 24 .
- the dresser 22 is pressed against the polishing surface 2a by the air cylinder 23, and with the dressing liquid present on the polishing surface 2a, the lower surface of the dressing member 22a is brought into sliding contact with the polishing surface 2a.
- the dresser arm 21 While the dresser 22 is rotating, the dresser arm 21 is turned (swinged) around the support shaft 26 to move the dresser 22 in the radial direction of the polishing surface 2a. In this manner, the polishing pad 2 is scraped off by the dresser 22, and the polishing surface 2a is dressed (regenerated).
- the polishing pad 2 has a fine uneven structure on the polishing surface 2a, and as the polishing of the substrate W progresses, the convex portions of the uneven structure collapse. Dressing regenerates the convex portion in an upright state.
- the operation control unit 9 includes a storage device 9a in which programs are stored, and a processing device 9b that executes operations according to instructions included in the programs.
- the processing device 9b includes a CPU (Central Processing Unit) or GPU (Graphic Processing Unit) that performs operations according to instructions included in programs stored in the storage device 9a.
- the storage device 9a comprises a main storage device (eg, random access memory) accessible by the processing unit 9b and a secondary storage device (eg, hard disk drive or solid state drive) for storing data and programs.
- the operation control section 9 is composed of at least one computer.
- the table rotation motor 3, the lifting mechanism (not shown), the polishing head rotation motor (not shown), the polishing liquid supply nozzle (not shown), the dressing device 20, and the surface texture measuring device 30 are controlled by the operation control unit 9. electrically connected. The operation of each component is controlled by the operation control section 9 .
- the polishing pad surface texture measuring apparatus 30 includes a measuring head 31 and a data processing section 50 electrically connected to the measuring head 31 .
- the polishing pad surface texture measuring device 30 is configured to measure the pad surface texture by irradiating the polishing pad 2 with light and receiving reflected light reflected from the surface (polishing surface 2a) of the polishing pad 2.
- the data processing unit 50 includes a storage device 50a in which programs are stored, and a processing device 50b that executes operations according to instructions included in the programs.
- the processing device 50b includes a CPU (Central Processing Unit) or GPU (Graphic Processing Unit) that performs operations according to instructions included in programs stored in the storage device 50a.
- Storage device 50a includes primary storage (eg, random access memory) accessible by processing unit 50b and secondary storage (eg, hard disk drive or solid state drive) for storing data and programs.
- the data processing unit 50 is composed of at least one computer. In one embodiment, the operation control section 9 and the data processing section 50 may be integrated.
- FIG. 2 is a schematic diagram showing an embodiment of the internal structure (measurement structure) of the measurement head 31.
- the measuring head 31 includes a light projecting section 32 that irradiates the polishing pad 2 with light, and a light receiving section 35 that receives light reflected by the surface of the polishing pad 2 (polishing surface 2a).
- the light projecting section 32 includes a light source 33 that emits light.
- An example of the light emitted from the light source 33 is laser light.
- the light source 33 is a laser light source that emits laser light. The laser light is applied to the irradiation position P on the polishing surface 2a.
- the light receiving section 35 has a light receiving element 36 .
- the light-receiving element 36 is a linear (one-dimensional) charge-coupled element having a dimension capable of receiving 0th-order diffracted light to n-order diffracted light (for example, 4th-order diffracted light or 7th-order diffracted light) of the light reflected from the polishing pad 2 . It consists of either a device (CCD) or a complementary metal oxide semiconductor (CMOS) device.
- CMOS complementary metal oxide semiconductor
- the light-receiving element 36 has a large number of light-receiving pixels, and is configured to be able to detect the received light intensity of reflected light for each pixel.
- the light projecting section 32 and the light receiving section 35 are electrically connected to the data processing section 50 .
- FIG. 3 is a schematic diagram showing another embodiment of the internal structure of the measuring head 31.
- the measurement head 31 of this embodiment includes a polarizer 38, an ND filter (neutral density filter) 39, and a mirror, which are sequentially arranged along the optical path of the laser beam emitted from the light projecting section 32. 40 are further provided.
- the mirror 40 is configured to be able to change the optical path by reflecting the laser light emitted from the light projecting section 32 .
- a light-reducing filter 41 is arranged in front of the light-receiving section 35 in the optical path of the reflected light reflected by the surface of the polishing pad 2 .
- the laser light emitted from the light projecting section 32 is S-polarized by the polarizer 38, the light quantity is adjusted by the ND filter 39, and the laser light enters the mirror 40 whose angle is adjusted in advance. Then, the laser beam is reflected by the mirror 40 to change its optical path, and is incident on the surface of the polishing pad 2 . Reflected light reflected by the surface of the polishing pad 2 passes through the neutral density filter 41 and is received by the light receiving section 33 . In one embodiment, instead of the neutral density filter 41, a bandpass filter that allows transmission of only a specific wavelength band may be arranged.
- the reflectance on the surface of the polishing pad 2 can be increased by causing the laser light emitted from the light source 33 to be S-polarized by the polarizer 38 and then incident on the polishing pad 2 .
- a band-pass filter may be used to pass only reflected light within ⁇ 5 nm with respect to the wavelength of the laser light from the light source 33 .
- laser light with a wavelength of 650 nm is used as the laser light from the light source 33 .
- FIG. 4 is a diagram for explaining reflected light from the polishing pad 2.
- the polishing pad 2 has a fine uneven structure on the polishing surface 2a, and the surface shape of the polishing pad 2 can be regarded as a superposition of simple (single-wavelength) spatial waveforms.
- the surface (polishing surface 2a) of the polishing pad 2 has a spatial waveform of wavelength ⁇ 1 and a spatial waveform of wavelength ⁇ 2.
- the reflected light from the polishing pad 2 includes scattered light from 0th-order diffracted light to n-th order diffracted light according to the wavelength (spatial wavelength) of each spatial waveform on the polishing surface 2a.
- the light receiving element 36 acquires the intensity distribution of the reflected light by receiving the reflected light including the scattered light.
- the intensity distribution of the reflected light is the distribution of the received light intensity for each light receiving position in the light receiving element 36 .
- the light-receiving element 36 is configured to receive light of spatial wavelengths that differ from pixel to pixel.
- the spatial wavelength of light received by each pixel can be calculated from the position of each pixel. Therefore, the intensity distribution of the reflected light acquired by the light receiving element 36 can also be said to be the intensity distribution of the spatial wavelength (or spatial frequency).
- the surface of the polishing pad 2 is irradiated with laser light from the light source 33 .
- the light receiving element 36 measures information on the surface of the polishing pad 2 by receiving the laser beam reflected by the surface of the polishing pad 2 .
- the light receiving element 36 acquires the intensity distribution of reflected light from the polishing pad 2 .
- the intensity distribution of the reflected light is transmitted to the data processing section 50 .
- the data processing unit 50 converts the intensity distribution of the reflected light into a spatial wavelength spectrum of the surface of the polishing pad 2 by Fourier transforming it.
- the data processing unit 50 calculates an index value that indirectly indicates the surface properties of the polishing pad 2 by calculating the spatial wavelength spectrum, and transfers the calculated index value to the operation control unit 9 .
- the operation control unit 9 determines dressing conditions and determines the surface properties of the polishing pad 2 based on the received index value. In one embodiment, the operation control unit 9 detects insufficient dressing, determines the end of dressing, and the like by determining the surface properties of the polishing pad 2 .
- FIG. 5 is a schematic diagram showing the spatial wavelength spectrum of the surface of the polishing pad 2. As shown in FIG. The vertical axis in FIG. 5 represents the intensity I( ⁇ ) of the reflected light obtained by the light receiving element 36, and the horizontal axis represents the spatial frequency. Spatial frequencies 1/ ⁇ 1 to 1/ ⁇ 4 are reciprocals of spatial wavelengths ⁇ 1 to ⁇ 4 .
- the data processing unit 50 calculates an index value that indirectly indicates the surface properties of the polishing pad 2 from the intensity distribution of the reflected light from the polishing pad 2 .
- An example of the index value is a wavelength composition ratio.
- the wavelength composition ratio is defined as the integrated value of the intensity of reflected light in a predetermined spatial wavelength region (hereinafter sometimes referred to as reflection intensity), of a wider spatial wavelength region including the predetermined spatial wavelength region. It is defined as the ratio to the integrated value of the reflection intensity.
- the larger the wavelength composition ratio the greater the intensity of the reflected light in the predetermined spatial wavelength region, which means that the measured surface of the polishing pad 2 contains more predetermined spatial wavelength components. It is shown that.
- the magnitude of the predetermined spatial wavelength component has a strong relationship with the CMP performance
- the spatial frequency 1 / ⁇ 3 that is, spatial wavelength ⁇ 3
- spatial frequency 1/ ⁇ 4 that is, spatial wavelength ⁇ 4
- the obtained spatial wavelength spectrum generally contains random noise over the entire wavelength range.
- the operation control unit 9 calculates suitable dressing conditions by closed loop control based on the wavelength composition ratio obtained by the data processing unit 50 .
- the dressing conditions are calculated so that the wavelength composition ratio changes within a preset range.
- the operation control unit 9 obtains in advance a relational expression showing the relationship between the dressing conditions and the wavelength composition ratio, and obtains a suitable dressing condition from the same expression.
- the dressing conditions mainly include the number of revolutions of the polishing pad, the number of revolutions of the dresser, the dressing load, the dresser rocking (turning) speed, and the like.
- the relationship between the dressing load and the pad surface texture is obtained in advance, that is, how much the wavelength composition ratio increases as the dressing load increases, or
- the ideal wavelength composition ratio is compared with the calculated wavelength composition ratio. set in a direction approaching a reasonable wavelength composition ratio.
- the difference between the calculated wavelength composition ratio and a predetermined desired wavelength composition ratio may be obtained as the desired pad surface property change amount.
- a previously created regression equation showing the relationship between the amount of change in at least one item of dressing load, number of revolutions of the dresser, number of revolutions of the polishing pad, and rocking (rotating) speed of the dresser and the amount of change in the surface properties of the pad, At least one of the dressing load, the number of revolutions of the dresser, the number of revolutions of the polishing pad, and the rocking speed of the dresser may be obtained by substituting the amount of change in surface properties.
- a regression equation representing the relationship between the dressing conditions (dressing load, dresser rotation speed, polishing pad rotation speed, dresser oscillation speed, etc.) and the wavelength composition ratio is obtained in advance.
- dR is the amount of change in wavelength composition ratio
- dL is the amount of change in dressing load
- a and B are constants.
- the wavelength composition ratio obtained by the data processing unit 50 may be used for abnormality detection.
- the operation control unit 9 determines that the pad surface property is abnormal, and issues an error notification or a notification that the dresser needs to be replaced. do.
- Types of abnormalities in the surface properties of the polishing pad include the presence of abnormal points (defects) on the surface of the polishing pad, insufficient dressing of the polishing pad, service life of the dresser, service life of the polishing pad, and the like.
- FIG. 6 is a perspective view schematically showing an embodiment in which the measuring head 31 is arranged at the measuring position.
- 7A is a front view of the measuring head 31, and
- FIG. 7B is a bottom view of the measuring head 31.
- the casing 43 accommodates therein a measuring structure for measuring the surface properties of the polishing pad 2 .
- the measurement structure accommodated inside the casing 43 includes, for example, the light projecting section 32, the light receiving section 35, the polarizer 38, the ND filter 39, the mirror 40, the neutral density filter 41, etc. described with reference to FIGS. is.
- a cutout 44 is formed in the lower portion of the casing 43 .
- the notch 44 has a trapezoidal shape defined by two opposing inclined surfaces 44a and 44b and a connecting surface 44c connecting the inclined surfaces 44a and 44b.
- a light-transmitting filter 47a is arranged on one inclined surface 44a, and the polishing pad 2 is irradiated with laser light emitted from the light source 33 through the filter 47a.
- a light-transmitting filter 47b is also arranged on the other inclined surface 44b, and the light receiving section 35 receives reflected light from the polishing pad 2 through the filter 47b.
- these filters 47a and 47b include, for example, a transparent film or transparent glass.
- the measuring head 31 has positioning plates 77 and 78 fixed to the side surfaces of the casing 43 .
- the positioning plates 77 and 78 come into contact with the polishing surface 2a of the polishing pad 2.
- FIG. The positioning plates 77, 78 make it possible to keep the vertical distance from the polishing surface 2a of the polishing pad 2 to the measuring structure of the measuring head 31 and the angle of the measuring head 31 with respect to the polishing surface 2a always constant.
- surface texture measuring device 30 may include nozzle 45 having a tip protruding from connecting surface 44c.
- the nozzle 45 is connected to a pressurized gas supply line (not shown), and blows pressurized gas (for example, pressurized nitrogen or pressurized air) from the pressurized gas supply line onto the polishing surface 2 a of the polishing pad 2 .
- pressurized gas for example, pressurized nitrogen or pressurized air
- the surface texture measuring device 30 can accurately measure the surface texture of the polishing pad 2 .
- FIG. 8 is an enlarged schematic diagram showing the periphery of the measuring head 31 shown in FIG.
- the measuring head 31 is supported by a support arm 51, and the support arm 51 is connected to a moving unit 53 fixed to a portion of the polishing apparatus.
- the moving unit 53 is a unit for moving the measuring head 31 from the retracted position to the measuring position or from the measuring position to the retracted position.
- the measurement position of the measurement head 31 is the position where the measurement head 31 is in contact with the polishing pad 2 in order to measure the surface properties of the polishing pad 2. is a position away from
- the moving unit 53 includes a fixed block 55 fixed to a part of the polishing apparatus, a rotating block 56 connected to the support arm 51, and the rotating block 56 attached to the fixed block 55.
- a rotating shaft 58 that is rotatably connected and a rotating mechanism 60 that rotates the rotating block 56 around the axis of the rotating shaft 58 are provided.
- a fixed block 55 is fixed to the frame 48 of the polishing apparatus.
- the support arm 51 is connected to the rotation block 56 via the support plate 52 .
- the rotating block 56 is connected to the stationary block 55 via a rotating shaft 58 .
- the rotation mechanism 60 is a piston-cylinder mechanism composed of a piston (not shown) connected to the rotation block 56 and a cylinder 63 that accommodates the piston so that it can move back and forth.
- the tip of the piston is connected to the rotation block 56 .
- a fluid supply line (not shown) is connected to the cylinder 63, and a fluid (for example, pressurized nitrogen or pressurized air) is supplied to the cylinder 63 through the fluid supply line.
- the motion control unit 9 moves the piston up and down by controlling the supply of fluid to the cylinder 63 .
- an on-off valve (not shown) is arranged in the fluid supply line, and the operation control unit 9 controls the operation of this on-off valve to move the piston up and down. More specifically, when the piston is lifted, the operation control section 9 opens the on-off valve and supplies fluid to the cylinder 63 . When lowering the piston, the operation control unit 9 closes the on-off valve to stop the supply of fluid to the cylinder 63 .
- the operation control section 9 moves the piston of the rotation mechanism 60 downward.
- the positioning plates 77 and 78 of the measuring head 31 come into contact with the polishing pad 2, and the measuring head 31 is positioned at the measuring position.
- the operation control section 9 raises the piston of the rotating mechanism 60 .
- the measuring head 31 is separated from the polishing pad 2, and the measuring head 31 moves to the retracted position.
- the rotation block 56 has a first plate 64 connected to the support plate 52 and a second plate 65 connected to the fixed block 55 via the rotation shaft 58 .
- the first plate 64 is rotatably connected to the second plate 65 by a hinge mechanism 87 .
- the hinge mechanism 87 includes a first joint 88 fixed to the upper surface of the first plate 64 , a second joint 89 fixed to the upper surface of the second plate 65 , and the first joint 88 rotated with respect to the second joint 89 . and a rotating pin 66 which is movably connected.
- the polishing apparatus further includes an attitude adjustment mechanism 70 that automatically adjusts the attitude of the measuring head 31.
- the attitude adjustment mechanism 70 includes a support base 72 connected to the support arm 51 and a plurality of adjustment pins 73 fixed to the upper surface of the measurement head 31 and extending through through holes formed in the support base 72 .
- four adjustment pins 73 are fixed to the top surface of the measuring head 31 .
- the support base 72 has a column 72a connected to the support arm 51 and a flange portion 72b fixed to the lower portion of the column 72a.
- Four through holes are formed in the four corners of the flange portion 72a.
- Each adjustment pin 73 extends through a respective through hole formed in flange 72b.
- the upper portion of the adjustment pin 73 has a diameter larger than the diameter of the through hole, and the diameter of the portion of the adjustment pin 73 penetrating the flange portion 72b is smaller than the diameter of the through hole. Therefore, the measuring head 31 is movable in a direction approaching the support base 72 and a direction away from the support base 72 .
- the positioning plates 77 and 78 of the measuring head 31 are brought into contact with the polishing surface 2a of the polishing pad 2, the measuring head 31 is supported on the polishing surface 2a of the polishing pad 2 by its own weight. Therefore, the posture of the measuring head 31 is adjusted so that the lower surface of the measuring head 31 is parallel to the surface of the polishing pad 2 (polishing surface 2a).
- the polishing apparatus further includes a measuring head moving mechanism 83 as an actuator that moves the measuring head 31 in the longitudinal direction of the support arm 51.
- the support arm 51 is arranged to extend in the radial direction of the polishing pad 2 when the measuring head 31 is in the measuring position. Therefore, the measuring head moving mechanism 83 moves the measuring head 31 in the radial direction of the polishing pad 2 .
- the measuring head moving mechanism 83 includes a ball screw mechanism 85 connected to the support base 72 and a servomotor 84 connected to the ball screw mechanism 85 .
- a servomotor 84 is fixed to the lower surface of the support arm 51 .
- the support arm 51 has an elongated hole 80 extending along its longitudinal direction.
- a stepped portion (not shown) is formed inside the elongated hole 80 .
- a support shaft 81 is fixed to the upper end of the support 72a. The support shaft 81 contacts the stepped portion of the elongated hole 80 and is supported by the stepped portion of the elongated hole 80 so as to be movable in the longitudinal direction of the elongated hole 80 .
- the measuring head 31 and the posture adjusting mechanism 70 are movable in the longitudinal direction of the support arm 51 . That is, the elongated hole 80 functions as a guide hole for moving the posture adjusting mechanism 70 and the measuring head 31 along the support arm 50 .
- the measuring head moving mechanism 83 is electrically connected to the operation control section 9 .
- the operation of the measuring head moving mechanism 83 is controlled by the operation control section 9 .
- the motion control unit 9 drives the servomotor 84, the ball screw mechanism 85 is driven, and the attitude adjustment mechanism 70 and the measuring head 31 are moved in the longitudinal direction of the support arm 51 (that is, in the radial direction of the polishing pad 2).
- the measuring head moving mechanism 83 may be a combination air cylinder and pressure regulator.
- FIG. 9 is a flow chart showing an example of incorporating the surface texture determination method of the polishing pad 2 into the break-in of the polishing pad 2 .
- Break-in is a process for making the surface (polishing surface) of an unused polishing pad suitable for polishing.
- the break-in includes at least a step (seasoning) of performing only dressing of the polishing pad 2 .
- break-in may further include multiple processing steps.
- the composite processing step is a step of dressing the polishing pad 2 after polishing one dummy wafer on which an oxide film (SiO 2 ) or metal film is formed.
- the multiple processing steps may be repeated multiple times with different dummy wafers to be polished. In one embodiment, a predetermined number of multiple processing steps are performed after seasoning.
- the surface properties of the polishing pad 2 are measured during break-in (step 1-2).
- the surface texture of polishing pad 2 is measured after performing dressing (seasoning) of polishing pad 2 for a predetermined period of time or after performing a predetermined number of combined treatment steps.
- step 1-2 the surface properties of the polishing pad 2 are measured. Specifically, the intensity distribution of the reflected light from the polishing pad 2 is obtained (measured) at a plurality of mutually different points (measurement points) on the surface of the polishing pad 2, and the plurality of intensity distributions obtained at the plurality of mutually different points are measured. A wavelength composition ratio indirectly indicating the surface properties of the polishing pad 2 is calculated from the intensity distribution.
- the process of acquiring the intensity distribution of reflected light from the polishing pad 2 is as follows. That is, the light emitting section 32 irradiates the surface of the polishing pad 2 with laser light, and the light receiving section 35 receives the reflected light from the polishing pad 2 . The light receiving section 35 acquires the intensity distribution of the reflected light from the polishing pad 2 by receiving the reflected light from the polishing pad 2 .
- the process of calculating the wavelength composition ratio that indirectly indicates the surface properties of the polishing pad 2 from a plurality of intensity distributions obtained at a plurality of locations different from each other is as follows.
- a plurality of wavelength composition ratios are calculated by calculating a wavelength composition ratio from each of the plurality of intensity distributions.
- the intensity distribution of reflected light acquired at each location is transmitted to the data processing unit 50 .
- the data processing unit 50 calculates a wavelength composition ratio that indirectly indicates the surface properties of the polishing pad 2 from the intensity distribution of the reflected light. More specifically, the data processing unit 50 converts the intensity distribution of the reflected light into a spatial wavelength spectrum of the surface of the polishing pad 2 by Fourier transform, and calculates the wavelength composition ratio from the spatial wavelength spectrum.
- the surface texture measurement process of the polishing pad 2 from the irradiation of the laser beam to the calculation of the wavelength composition ratio described above is performed a plurality of times while changing the irradiation position of the laser beam.
- the data processing unit 50 averages the plurality of intensity distributions, and calculates a wavelength composition ratio that indirectly indicates the surface properties of the polishing pad 2 from the averaged intensity distribution of the reflected light. good. Specifically, intensity distributions of a plurality of reflected lights are averaged by averaging intensities for each pixel of a plurality of intensity distributions. By calculating the wavelength composition ratio after averaging the intensity distribution, it is possible to efficiently calculate the wavelength composition ratio.
- the intensity distribution of reflected light from the polishing pad 2 is obtained (measured) at a plurality of points on at least one circumference centered on the center O of the polishing pad 2 .
- the intensity distribution is measured at a plurality of points on a plurality of concentric circles around the center O of the polishing pad 2 .
- FIG. 10 is a diagram showing an example of a plurality of measurement points on the surface of polishing pad 2. As shown in FIG. In the example shown in FIG. 10, the intensity distribution is measured at a plurality of measurement points P11 to P15, P21 to P25, P31 to P35 on a plurality of concentric circles C1, C2, C3 centered on the center O of the polishing pad 2. be.
- the number of measurement points for the intensity distribution is not limited to this example.
- the measurement of the intensity distribution of reflected light from the polishing pad 2 at multiple points on the surface of the polishing pad 2 is performed as follows. First, the measurement head 31 is moved to a predetermined position, and the intensity distribution is measured. Next, the polishing table 1 is rotated together with the polishing pad 2 by a predetermined angle, and the intensity distribution of the reflected light from the polishing pad 2 is measured again. By repeating the rotation of the polishing table 1 and the measurement of the intensity distribution described above while the position of the measuring head 31 is fixed, a plurality of measurements are performed on the same circumference with the center O as the center.
- the measuring head moving mechanism 83 moves the measuring head 31 in the radial direction of the polishing pad 2, and similarly, the other circumferences around the center O are measured.
- the intensity distribution of the reflected light from the polishing pad 2 is measured at a plurality of points on the same circumference.
- step 1-3 the quality of the surface properties of the polishing pad 2 is determined based on the wavelength composition ratio calculated in step 1-2.
- the data processing unit 50 transmits the wavelength composition ratio calculated in step 1-2 to the operation control unit 9, and the operation control unit 9 determines the quality of the surface texture of the polishing pad 2 based on the calculated wavelength composition ratio. judge.
- the operation control unit 9 determines that the surface properties of the polishing pad 2 are good, it issues a command to each component of the polishing apparatus to end the break-in.
- the operation control unit 9 calculates an average value of the calculated plurality of wavelength composition ratios, and determines the average value in advance. When the average value is smaller than the threshold, it is determined that the surface properties of the polishing pad 2 are good (the surface of the polishing pad 2 has become suitable for polishing). and terminate the break-in (step 1-4). When the average value is larger than the threshold value, the operation control unit 9 determines that the surface properties of the polishing pad 2 are not good (the surface of the polishing pad 2 is not suitable for polishing), Continue break-in (step 1-5). After performing the seasoning for a predetermined time or performing the combined processing steps a predetermined number of times, step 1-2 is executed again.
- the wavelength composition ratio calculated from the averaged intensity distribution of reflected light may be compared with a predetermined threshold value. In this embodiment, when the wavelength composition ratio is smaller than the threshold value, it is determined that the surface properties of the polishing pad 2 are good, and the break-in ends. When the wavelength composition ratio is larger than the threshold value, the operation control unit 9 determines that the surface properties of the polishing pad 2 are not good, and continues break-in. After performing the seasoning for a predetermined time or performing the combined processing steps a predetermined number of times, step 1-2 is executed again.
- the average value when the average value (or the wavelength composition ratio calculated from the average intensity distribution of the reflected light) is larger than the threshold value, it is determined that the surface properties of the polishing pad 2 are good. , may end the break-in.
- the average value or the wavelength composition ratio calculated from the averaged intensity distribution of the reflected light
- the polishing pad 2 The surface properties of may be improved.
- the operation control unit 9 checks whether or not the calculated multiple wavelength configuration ratios are within a predetermined reference range, and all of the calculated multiple wavelength configuration ratios are within the predetermined range. When it is within the reference range, it may be determined that the surface properties of the polishing pad 2 are good, and the break-in may be terminated. If all of the plurality of wavelength composition ratios are not within the predetermined reference range, the operation control section 9 determines that the surface properties of the polishing pad 2 are not good, and continues break-in. After performing the seasoning for a predetermined time or performing the combined processing steps a predetermined number of times, step 1-2 is executed again.
- the operation control unit 9 calculates an average value of the calculated multiple wavelength configuration ratios, compares the average value with a predetermined threshold value, and calculates the calculated multiple wavelength configuration ratios. It is checked whether the ratio is within a predetermined reference range, and the average value is smaller (or larger) than the threshold value, and all of the calculated multiple wavelength composition ratios are within the predetermined reference range. When it is within the range, it may be determined that the surface properties of the polishing pad 2 are good, and the break-in may be terminated.
- the threshold value and the reference range described above can be set from measurement data of the surface texture of the polishing pad 2 after dressing or after break-in that has been obtained in advance.
- the convex portions of the uneven structure of the polishing surface 2a are raised, and the in-plane uniformity of the uneven structure is improved.
- the magnitude of the wavelength composition ratio and the in-plane variation at a plurality of measurement points on the surface of the polishing pad 2 are reduced. That is, the wavelength composition ratio indirectly indicates the surface properties of the polishing pad 2 . Therefore, it is possible to determine the surface properties of the polishing pad 2 (for example, detection of insufficient dressing and determination of completion of dressing) based on the wavelength composition ratio.
- the intensity distribution of the reflected light from the polishing pad 2 at a plurality of points on the surface of the polishing pad 2, it is possible to evaluate the surface properties of the polishing pad including in-plane variations.
- the surface texture of the polishing pad 2 (the surface texture of the entire polishing pad 2) can be accurately determined. be able to.
- excessive dressing and break-in can be prevented, which contributes to prolonging the life of the dresser.
- the break-in time can be shortened for a polishing pad whose protrusions rise quickly, and sufficient break-in can be performed for a pad whose protrusions rise slowly. That is, the break-in time can be adjusted according to the individual difference of polishing pads.
- steps 1-2 to 1-5 may be executed each time a new polishing pad (unused polishing pad) is replaced, and the end of break-in may be individually determined. Furthermore, in one embodiment, steps 1-2 to 1-5 are performed once for a new polishing pad to determine appropriate break-in conditions, and after that, when the polishing pad is replaced with a new one, the break-in conditions are determined. A break-in may be executed with a break-in condition. Further, in one embodiment, a plurality of break-in termination conditions are determined by executing steps 1-2 to 1-5 in the break-in of a plurality of brand-new polishing pads, and the plurality of break-in termination conditions are met. Based on this, the upper limit of the break-in end condition may be set.
- FIG. 11 is a graph showing an example of the wavelength composition ratio for each processing condition of the polishing pad 2 during break-in.
- the intensity distribution of reflected light from the polishing pad 2 was measured at a plurality of locations on the polishing pad 2, and the wavelength composition ratio was calculated from each intensity distribution. shows the results.
- the measured values in FIG. 11 show the measured values (wavelength composition ratio) obtained at each measurement position on the polishing pad.
- Examples of processing conditions shown in FIG. 11 include seasoning time and the number of combined processing steps. In FIG. 11, in conditions 2 to 6, the larger the condition number, the longer the seasoning time. In conditions 7 to 10, the larger the condition number, the greater the number of combined processing steps.
- conditions 2 to 6 only seasoning is performed, and in conditions 7 to 10, after performing seasoning for a predetermined period of time, a combined treatment process is performed a predetermined number of times.
- the dressing time in each compound processing step of Conditions 7-10 is the same, and the seasoning time of Conditions 7-10 is the same.
- the measurement results of condition 1 show the measurement results of an unused polishing pad before break-in.
- FIG. 12A is a diagram comparing the wavelength composition ratio under condition 1 in FIG. 11 with a predetermined reference range and a predetermined threshold value
- FIG. 12B is a diagram comparing the wavelength composition ratio under condition 6 in FIG.
- FIG. 12C is a diagram comparing ranges and predetermined thresholds
- FIG. 12C is a diagram comparing wavelength composition ratios under condition 10 in FIG. 11 with predetermined reference ranges and predetermined thresholds.
- the threshold is not shown in FIG. 12A because it is well below the measured (calculated) wavelength composition ratio.
- the wavelength composition ratio indirectly indicating the surface properties of the polishing pad 2 is calculated from a plurality of intensity distributions obtained at a plurality of locations different from each other, the entire polishing pad is in a state suitable for polishing. It can be determined whether or not
- FIG. 13 is a flow chart showing an example of incorporating the surface texture determination method of the polishing pad 2 into the polishing process of the substrate W. As shown in FIG. Since the surface texture determination method of this embodiment, which is not specifically described, is the same as steps 1-2 and 1-3, redundant description thereof will be omitted.
- the substrate W is polished in step 2-1.
- the polishing pad 2 is dressed.
- the dressing of the polishing pad 2 may be performed at the same time as the substrate W is polished. Further, in one embodiment, the polishing pad 2 may be dressed after polishing a predetermined number of substrates.
- the surface properties of the polishing pad 2 are measured by the same method as in step 1-2 (step 2-3). In one embodiment, step 2-3 may be performed at any timing (eg, after each dressing, for each lot of substrates to be polished, or after polishing a predetermined number of substrates and after dressing). .
- the quality of the surface properties of the polishing pad 2 is determined by the same method as in step 1-3. In one embodiment, the surface texture determination process (steps 2-3 to 2-5) may be performed simultaneously with the polishing pad 2 dressing.
- FIG. 14 shows the result of measuring the surface properties of the polishing pad 2 after dressing the polishing pad 2 under predetermined dressing conditions while polishing the substrate W, and calculating the wavelength composition ratio.
- One example of the dressing condition shown in FIG. 14 is the number of scans of the dresser arm 21 .
- Condition 11 in FIG. 14 is a dressing condition when the polishing pad 2 is appropriately dressed (that is, when the surface properties of the polishing pad 2 are good).
- Conditions 12 to 15 in FIG. 14 are measurement results of the surface properties of the polishing pad 2 after dressing when the polishing pad 2 was dressed only during polishing of the substrate W.
- Condition 11 is during polishing of the substrate W. 2 shows the measurement results of the surface properties of the polishing pad 2 after dressing the polishing pad 2 under predetermined conditions in 1 and then dressing the polishing pad 2 again after polishing.
- the operation control unit 9 determines that the surface properties of the polishing pad 2 are good (that is, the dressing has been performed appropriately), it starts polishing a new substrate.
- the operation control unit 9 determines that the surface quality of the polishing pad 2 is not good (insufficient dressing)
- the operation control unit 9 reduces the number of repetitions of additional dressing in step 2-6 described later to a predetermined number of times. Compare with a reference value (step 2-5). If the number of repetitions is greater than a predetermined repetition reference value, the operation control unit 9 generates an alarm signal to prompt the operator to consider replacing consumable parts of the polishing apparatus (step 2-7). Consumable parts of the polishing apparatus include the polishing pad 2, dressing member 22a, and slurry.
- step 2-6 additional dressing of the polishing pad 2 is performed under predetermined dressing conditions (step 2-6), and after the additional dressing is performed, step 2-3 is performed again.
- the dressing conditions (eg, dressing time) in step 2-6 may differ from the dressing conditions in step 2-2.
- the surface texture of the polishing pad 2 (the surface texture of the entire polishing pad 2) can be accurately determined.
- the lack of dressing is determined, and if necessary, additional dressing is performed to continue polishing, and consumable parts (for example, dressing members) are exchanged with high precision based on the surface properties of the polishing pad. can be determined.
- steps 2-2 to 2-6 are a series of dressing steps performed after (or during) polishing of the substrate W, and step 2-4 determines the end of the dressing step.
- step 2-4 determines the end of the dressing step.
- FIG. 15 is a schematic diagram showing another embodiment of the surface texture measuring device 30.
- the configuration and operation of this embodiment, which are not specifically described, are the same as those of the above-described embodiment, and thus overlapping descriptions thereof will be omitted.
- the light emitting section 32 of the present embodiment is configured to be able to irradiate the polishing pad 2 with light from a plurality of directions when the polishing pad 2 is viewed from the polishing surface 2a side of the polishing pad 2.
- the irradiation direction of the laser light means the irradiation direction of the laser light when the polishing pad 2 is viewed from the surface (polishing surface 2a) side.
- the surface texture measuring device 30 of this embodiment further includes an irradiation direction changing mechanism 90 that changes the irradiation direction of the laser beam emitted from the light projecting section 32 .
- the irradiation direction changing mechanism 90 is connected to the measurement head 31 .
- the irradiation direction changing mechanism 90 rotatably supports the measuring head 31 and is configured to change the irradiation direction of the laser beam emitted from the light projecting section 32 by rotating the measuring head 31 .
- the irradiation direction changing mechanism 90 includes a rotating motor 91 that rotates the measuring head 31 and a shaft 92 connected to the rotating motor 91 .
- the measuring head 31 is connected to a rotary motor 91 via a shaft 92 .
- the rotating motor 91 rotates the measuring head 31 about the axis AX2 of the shaft 92 in the direction indicated by the arrow.
- the rotary motor 91 incorporates an angle measuring device 93 for measuring the rotation angle of the measuring head 31 .
- the rotary motor 91 is configured to be able to control its rotation angle.
- An example of the rotary motor 91 is a servomotor.
- An example of the angle measuring device 93 is a rotary encoder.
- the irradiation direction changing mechanism 90 is electrically connected to the data processing unit 50 , and the operation of the irradiation direction changing mechanism 90 is controlled by the data processing unit 50 .
- the irradiation direction changing mechanism 90 is fixed to the lower surface of the base plate 74 and connected to the posture adjusting mechanism 70 via the base plate 74 .
- the lower end of the adjustment pin 73 is fixed to the upper surface of the base plate 74 .
- the shaft 92 may be rotatably supported by bearings (not shown) instead of the rotary motor 91 . In this case, the measurement head 31 may be manually rotated, and the irradiation direction changing mechanism 90 may not be electrically connected to the data processing section 50 .
- the light projecting part 32 and the light receiving part 35 rotate around the axis AX2 of the shaft 93 .
- the axial center AX2 and the axial center CP (see FIG. 2), which is a straight line passing through the irradiation position P of the laser beam and perpendicular to the polishing surface 2a, are aligned. Therefore, as shown in FIG. 16, the light projecting section 32 and the light receiving section 35 are configured to be rotatable about the axis CP.
- the measuring head 31 that is, the light projecting section 32 and the light receiving section 35 rotate around the axis CP. Thereby, the irradiation direction of the laser light emitted from the light projecting section 32 is changed.
- the irradiation direction of the laser light can also be said to be an angle around the axis CP.
- the irradiation angle ⁇ of the laser beam is defined by the laser beam emitted from the light source 33 of the light projecting section 32 and the reference straight line RL when viewed from the direction perpendicular to the surface of the polishing pad 2 (polishing surface 2a). is the angle.
- the reference straight line RL is a straight line passing through the irradiation position P and the center O of the polishing pad 2 .
- the irradiation direction of the laser light can be changed without moving the irradiation position of the laser light.
- step 3-1 multidirectional measurement of the surface properties of the polishing pad 2 (intensity distribution of reflected light from the polishing pad 2) is performed.
- the multidirectional measurement of the surface texture of the polishing pad 2 is performed by irradiating the polishing pad 2 with laser light from a plurality of irradiation directions different from each other, and measuring the light from the polishing pad 2 corresponding to each of the plurality of laser light irradiated on the polishing pad 2.
- the light projecting section 32 irradiates the polishing pad 2 with laser light from a predetermined irradiation direction, and the light receiving section 35 receives the reflected light from the polishing pad 2 .
- the light receiving section 35 acquires the intensity distribution of the reflected light from the polishing pad 2 by receiving the reflected light from the polishing pad 2 .
- the irradiation direction of the laser beam is changed by a predetermined angle by the irradiation direction changing mechanism 90
- the polishing pad 2 is irradiated with the laser beam from the changed irradiation direction, and the reflected light of the laser beam from the polishing pad 2 is received by the light receiving unit.
- 35 receives the light and obtains the intensity distribution of the reflected light.
- the irradiation direction of the laser light is further changed by a predetermined angle, and the surface properties of the polishing pad 2 are measured from the changed direction.
- the change of the irradiation direction of the laser beam and the measurement of the surface texture of the polishing pad 2 are repeated a predetermined number of times (for example, until the light source 33 makes one turn around the axis CP).
- the measurement position for multi-directional measurement of the surface properties of the polishing pad 2 in this embodiment is the position on the polishing pad 2 with which the central portion of the substrate W contacts during polishing. Insufficient dressing is likely to occur at a location on the polishing pad 2 with which the central portion of the substrate W contacts, so the intensity of the reflected light is relatively high.
- the surface texture of the polishing pad 2 is measured multiple times in each irradiation direction, the intensity distributions of the multiple reflected lights are averaged, and the averaged intensity distribution is used in step 3-2 described later. You may By averaging the intensity distributions of a plurality of reflected lights, the measurement variation can be reduced and the accuracy of the measurement result can be improved.
- index values that indirectly indicate the surface properties of the polishing pad 2 are obtained using the plurality of intensity distributions obtained in the multidirectional measurement in step 3-1.
- the data processing unit 50 of the present embodiment utilizes the intensity distribution of a plurality of reflected lights from the polishing pad 2 of a plurality of lights irradiated to the polishing pad 2 from a plurality of directions different from each other to determine the surface properties of the polishing pad 2. is configured to acquire an index value that indirectly indicates the
- step 3-2 the data processing unit 50 compares a plurality of intensity distributions of a plurality of reflected lights from the polishing pad 2 of a plurality of laser beams irradiated onto the polishing pad 2 from a plurality of angles different from each other, and identifies , the irradiation direction of the laser beam that maximizes the intensity of the reflected light from the polishing pad 2 in the spatial wavelength region of . More specifically, the data processing unit 50 averages the intensity in a specific spatial wavelength region of each intensity distribution (that is, pixels within a predetermined range that receive reflected light in a specific spatial wavelength region of the light receiving element 36). A value is calculated, each calculated average value is compared, and the irradiation direction that maximizes the average value is determined.
- the data processing unit 50 compares the intensity of the reflected light of a predetermined pixel (pixel position) in each irradiation direction, and determines the irradiation direction that maximizes the intensity of the reflected light in the predetermined pixel. good too. Furthermore, in one embodiment, the data processing unit 50 selects pixels that are most susceptible to changes in irradiation direction (that is, pixels that exhibit the largest change in intensity depending on the irradiation direction) as pixels for comparing the intensity of reflected light. Alternatively, a pixel having the highest intensity of reflected light among a plurality of distributions of reflected light may be used as a pixel for comparing the intensity of reflected light.
- 18 to 25 are graphs showing the intensity distribution of reflected light from the polishing pad 2 in each irradiation direction.
- the horizontal axis of the graphs of FIGS. 18 to 25 indicates pixels (pixel positions), and the vertical axis indicates the intensity of reflected light from the polishing pad 2 at each pixel.
- 18 to 25 show intensity distributions of reflected light from the polishing pad 2 when the irradiation angles ⁇ are 0°, 45°, 90°, 135°, 180°, 225°, 270° and 315°, respectively. graph.
- the intensity around pixel 1/ ⁇ 5 is high. It can be understood that this is because the convex portions of the concave-convex structure of the polished surface 2a are tilted in the direction of 90°, and the reflectance in the direction of 90° is increased.
- the protrusions are tilted in the direction of 90°, it can be understood that the uneven structure corresponding to the long spatial wavelength exists in the direction of 90° on the surface of the polishing pad 2 . 18 to 25 correspond to the long spatial wavelength, and the pixels in the region with small intensity change for each irradiation angle on the right side of the graphs of FIGS. , corresponds to the short-wave spatial wavelength.
- the measured value of the surface texture of the polishing pad 2 changes depending on the irradiation direction. That is, in order to examine the relationship between the state of the polishing pad 2 and the polishing performance and optimize the dressing conditions, it is more useful to obtain multi-directional unevenness information rather than unidirectional unevenness information.
- the surface state of the polishing pad 2 can be evaluated in more detail, and the dressing can be performed. Conditions can be optimized.
- the irradiation direction of the laser light is changed every 45°, but the change pitch of the irradiation direction is not limited to this embodiment.
- the irradiation direction of the laser beam emitted from the light source 33 of the light projecting unit 32 is the irradiation direction determined in step 3-2, that is, the intensity of the reflected light from the polishing pad 2 in the specific spatial wavelength region is
- the irradiation direction of the laser beam is set so as to maximize the irradiation direction.
- the irradiation direction of the laser beam is set by adjusting the angles of the light projecting section 32 and the light receiving section 35 using the irradiation direction changing mechanism 90 .
- the irradiation direction of the laser light becomes the optimum direction for measuring the surface properties of the polishing pad 2 .
- the measurement accuracy of the surface texture of the polishing pad 2 can be improved, resulting in a more precise measurement. It is possible to determine the surface properties of the polishing pad 2 and optimize the dressing conditions.
- Steps 3-1 to 3-3 may be performed each time before the surface texture measurement of the polishing pad 2, and are performed only once to determine the process of surface texture measurement of the polishing pad.
- the direction setting step may be performed before the surface texture measurement of the polishing pad 2 in step 1-2 described with reference to FIG. It may be performed before the property measurement.
- step 3-4 the surface properties of the polishing pad 2 are measured at multiple points. Specifically, the intensity distribution of the reflected light from the polishing pad 2 is measured at a plurality of different points on the surface of the polishing pad 2 .
- the method of measuring the intensity distribution at multiple points on the surface of the polishing pad 2 is the same as in step 1-2.
- step 3-5 the data processing unit 50 averages the intensity distributions of the multiple reflected lights acquired in step 3-4. Specifically, intensity distributions of a plurality of reflected lights are averaged by averaging intensities for each pixel of a plurality of intensity distributions. By executing step 3-6 described later after averaging the intensity distribution, an index value that indirectly indicates the surface properties of the polishing pad 2 can be efficiently calculated.
- the data processing unit 50 calculates an index value that indirectly indicates the surface properties of the polishing pad 2 from the averaged intensity distribution of the reflected light of the polishing pad 2.
- the index value that indirectly indicates the surface properties of the polishing pad 2 is the wavelength composition ratio described above.
- the data processing unit 50 converts the intensity distribution of the reflected light into a spatial wavelength spectrum of the surface of the polishing pad 2 by Fourier transform, and calculates a wavelength composition ratio from the spatial wavelength spectrum. In this manner, the data processing section 50 acquires index values that indirectly indicate the surface properties of the polishing pad 2 .
- index values that indirectly indicate the surface texture of the polishing pad 2 may be calculated from each of the plurality of intensity distributions obtained in step 3-4. In this case, steps 3-5 are not performed.
- FIG. 26 is a schematic diagram showing still another embodiment of the surface texture measuring device 30, and FIG. 27 is a top view of the measuring head 31 shown in FIG.
- the configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to FIGS.
- the surface texture measuring device 30 of this embodiment differs from the embodiment described with reference to FIG. 15 in that it does not include an irradiation direction changing mechanism 90 .
- the attitude adjustment mechanism 70 is connected to the measurement head 31 and the adjustment pin 73 is fixed to the upper surface of the measurement head 31, as in the embodiment described with reference to FIG.
- the light projecting section 32 includes a plurality of light sources 33a, 33b, and 33c arranged facing different directions, and the light receiving section 35 faces in different directions. It has a plurality of light receiving elements 36a, 36b, 36c arranged in the same manner. Specifically, the light sources 33a, 33b, and 33c are arranged facing different directions when the polishing pad 2 is viewed from the polishing surface 2a side of the polishing pad 2, and the light receiving elements 36a, 36b, and 36c , are arranged facing different directions when the polishing pad 2 is viewed from the polishing surface 2a side of the polishing pad 2. As shown in FIG.
- the light sources 33a, 33b, and 33c are arranged so as to be able to irradiate the same position (irradiation position P) with laser light.
- the configurations of the light sources 33a, 33b, 33c and the light receiving elements 36a, 36b, 36c are the same as those of the light source 33 and the light receiving elements 36, respectively.
- the light receiving elements 36a, 36b, and 36c face the light sources 33a, 33b, and 33c, respectively, and are configured to be able to receive the reflected light from the polishing pad 2 of the laser beams emitted from the light sources 33a, 33b, and 33c, respectively.
- the light projecting section 32 of the present embodiment can irradiate the polishing pad 2 with light from a plurality of irradiation directions different from each other when the polishing pad 2 is viewed from the polishing surface 2a side of the polishing pad 2.
- the light receiving section 35 is configured to receive light reflected from the surface of the polishing pad 2 from a plurality of directions.
- the irradiation angle of the laser light from the light source 33a is 0°
- the irradiation angle ⁇ 1 of the laser light from the light source 33b is 45°
- the irradiation angle ⁇ 2 of the laser light from the light source 33c is 90°.
- the number and arrangement angles of the light sources are not limited to those of this embodiment.
- the surface properties of the polishing pad 2 intensity distribution of reflected light from the polishing pad 2 can be measured in a plurality of irradiation directions at once.
- the surface texture measuring method of this embodiment which is not specifically described, is the same as the method described with reference to FIG.
- laser light is emitted from a plurality of light sources 33a, 33b, and 33c from a plurality of irradiation directions.
- a plurality of light beams reflected from the polishing pad 2 corresponding to the plurality of laser beams irradiated to the polishing pad 2 are received by the plurality of light receiving elements 36a, 36b, and 36c.
- step 3-3 instead of adjusting the angles (directions) of the light projecting unit 32 and the light receiving unit 35 by the irradiation direction changing mechanism 90, the light reflected from the polishing pad 2 is in a specific spatial wavelength region.
- the irradiation direction of the laser light is set by selecting a light source that irradiates the laser light in the irradiation direction in which the intensity is maximized.
- the surface properties of the polishing pad 2 are measured using the selected light source and the light receiving element facing the selected light source.
- the embodiment described with reference to FIGS. 15-25 may be combined with the embodiment described with reference to FIGS.
- the surface properties of the polishing pad 2 (the intensity distribution of the reflected light from the polishing pad 2) can be measured in a plurality of irradiation directions at once, and the step of changing the irradiation direction of the laser light in step 3-1 can be eliminated. can be shortened.
- a two-dimensional CCD may be used as the light receiving element 36 .
- the reflected light can be received by the light-receiving element 36 without the need for adjustment even when the laser light is shifted in the horizontal direction.
- the above-described embodiment can also be used to determine dressing conditions for each substrate processing.
- the above-described embodiments are described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention.
- Various modifications of the above-described embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in its broadest scope in accordance with the technical spirit defined by the claims.
- the present invention can be used for a surface texture measuring apparatus, a polishing pad surface texture measuring method, and a polishing pad surface texture determining method used for polishing substrates such as semiconductor wafers.
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Abstract
Description
一態様では、前記照射方向変更機構は、前記投光部および前記受光部を回転させる回転モータと、前記回転モータに連結されたシャフトを備えている。
一態様では、前記投光部は、互いに異なる方向を向いて配置された複数の光源を備え、前記受光部は、互いに異なる方向を向いて配置された複数の受光素子を備えている。
一態様では、前記表面性状測定装置は、前記受光部に電気的に接続されたデータ処理部をさらに備え、前記データ処理部は、互いに異なる複数の方向から前記研磨パッドに照射された複数の光の前記研磨パッドからの複数の反射光の強度分布を利用して、前記研磨パッドの表面性状を間接的に示す指標値を取得するように構成されている。
一態様では、前記互いに異なる複数の照射方向から前記研磨パッドに光を照射し、前記研磨パッドに照射された前記複数の光のそれぞれに対応する前記研磨パッドからの前記複数の反射光を受光する工程は、複数の光源によって、複数の照射方向から光を前記研磨パッドに照射し、前記研磨パッドに照射された複数の光のそれぞれに対応する研磨パッドからの複数の反射光を複数の受光素子で受光する工程を含む。
一態様では、前記複数の箇所で取得された複数の前記強度分布から前記研磨パッドの表面性状を間接的に示す波長構成比を算出する工程は、前記複数の強度分布を平均化し、平均化された反射光の強度分布から、前記波長構成比を算出する工程を含む。
一態様では、前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程は、前記算出された複数の波長構成比が予め定められた基準範囲内にあるか否かを確認し、前記算出された複数の波長構成比の全てが予め定められた基準範囲内にあるときに、前記研磨パッドの表面性状が良好であると判定する工程を含む。
一態様では、前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程は、前記算出された複数の波長構成比の平均値を算出し、前記平均値と予め定められたしきい値を比較し、かつ前記算出された複数の波長構成比が予め定められた基準範囲内にあるか否かを確認し、前記平均値が前記しきい値よりも小さく、かつ前記算出された複数の波長構成比の全てが前記基準範囲内にあるときに前記研磨パッドの表面性状が良好であると判定する工程を含む。
一態様では、前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程は、前記算出された複数の波長構成比の平均値を算出し、前記平均値と予め定められたしきい値を比較し、かつ前記算出された複数の波長構成比が予め定められた基準範囲内にあるか否かを確認し、前記平均値が前記しきい値よりも大きく、かつ前記算出された複数の波長構成比の全てが前記基準範囲内にあるときに前記研磨パッドの表面性状が良好であると判定する工程を含む。
一態様では、前記方法は、前記研磨パッドの表面性状が良好であると判定した場合、前記研磨パッドのブレークインを終了する工程をさらに含む。
図1は、研磨パッドの表面性状測定装置を備えた研磨装置の一実施形態を示す模式図である。図1に示すように、研磨装置(CMP装置)は、研磨パッド2を支持する研磨テーブル1と、研磨対象物である半導体ウエハ等の基板Wを保持して研磨テーブル上の研磨パッドに押圧する研磨ヘッド10と、研磨パッド2をドレッシングするドレッシング装置20と、研磨パッド2の表面形状や表面状態などの表面性状を測定する研磨パッドの表面性状測定装置30と、研磨装置の各構成要素の動作を制御する動作制御部9とを備えている。
研磨パッドの表面性状の異常の種類として、研磨パッド表面の異常な点(欠陥)の存在、研磨パッドのドレッシング不足、ドレッサーの寿命、研磨パッドの寿命などが挙げられる。
図12Aでは、しきい値は、波長構成比の測定値(算出値)よりもかなり下にあるため、図12Aには、しきい値は図示されていない。
2 研磨パッド
3 テーブル回転モータ
4 テーブル軸
9 動作制御部
10 研磨ヘッド
11 研磨ヘッドシャフト
12 研磨ヘッド揺動アーム
20 ドレッシング装置
21 ドレッサーアーム
22 ドレッサー
23 エアシリンダ
24 ドレッサーシャフト
26 支軸
27 支軸回転モータ
30 表面性状測定装置
31 測定ヘッド
32 投光部
33 光源
33a,33b,33c 光源
35 受光部
36 受光素子
36a,36b,36c 受光素子
38 偏光子
39 NDフィルター
40 ミラー
41 減光フィルター
43 ケーシング
44 切り欠き
45 ノズル
47a,47b フィルター
50 データ処理部
51 支持アーム
52 支持プレート
53 移動ユニット
55 固定ブロック
56 回動ブロック
58 回転軸
60 回動機構
63 シリンダ
66 回転ピン
70 姿勢調整機構
72 支持台
73 調整ピン
74 ベースプレート
77,78 位置決めプレート
80 長穴
81 支持軸
83 測定ヘッド移動機構
84 サーボモータ
85 ボールねじ機構
87 ヒンジ機構
90 照射方向変更機構
91 回転モータ
92 シャフト
93 角度測定装置
Claims (15)
- 基板の研磨に使用される研磨パッドの表面性状測定装置であって、
前記研磨パッドを前記研磨パッドの研磨面側から見たときに、光を複数の方向から前記研磨パッドに照射可能な投光部と、
前記研磨パッドの表面で反射した複数の方向からの反射光を受光可能な受光部を備えている、表面性状測定装置。 - 前記光の照射方向を変更する照射方向変更機構をさらに備えている、請求項1に記載の表面性状測定装置。
- 前記照射方向変更機構は、前記投光部および前記受光部を回転させる回転モータと、前記回転モータに連結されたシャフトを備えている、請求項2に記載の表面性状測定装置。
- 前記投光部は、互いに異なる方向を向いて配置された複数の光源を備え、
前記受光部は、互いに異なる方向を向いて配置された複数の受光素子を備えている、請求項1乃至3のいずれか一項に記載の表面性状測定装置。 - 前記受光部に電気的に接続されたデータ処理部をさらに備え、
前記データ処理部は、互いに異なる複数の方向から前記研磨パッドに照射された複数の光の前記研磨パッドからの複数の反射光の強度分布を利用して、前記研磨パッドの表面性状を間接的に示す指標値を取得するように構成されている、請求項1乃至4のいずれか一項に記載の表面性状測定装置。 - 互いに異なる複数の照射方向から研磨パッドに光を照射し、
前記研磨パッドに照射された複数の光のそれぞれに対応する前記研磨パッドからの複数の反射光を受光し、複数の反射光の強度分布を取得し、
前記複数の強度分布を利用して、前記研磨パッドの表面性状を間接的に示す指標値を取得する工程を含み、
前記照射方向は、前記研磨パッドを前記研磨パッドの研磨面側から見たときの方向である、研磨パッドの表面性状測定方法。 - 前記互いに異なる複数の照射方向から前記研磨パッドに光を照射し、
前記研磨パッドに照射された前記複数の光のそれぞれに対応する前記研磨パッドからの前記複数の反射光を受光する工程は、
前記光の照射方向を変更しながら、前記光を前記研磨パッドに照射し、各照射方向における光の前記研磨パッドからの各反射光を受光する工程を含む、請求項6に記載の研磨パッドの表面性状測定方法。 - 前記互いに異なる複数の照射方向から前記研磨パッドに光を照射し、
前記研磨パッドに照射された前記複数の光のそれぞれに対応する前記研磨パッドからの前記複数の反射光を受光する工程は、
複数の光源によって、複数の照射方向から光を前記研磨パッドに照射し、前記研磨パッドに照射された複数の光のそれぞれに対応する研磨パッドからの複数の反射光を複数の受光素子で受光する工程を含む、請求項6または7に記載の研磨パッドの表面性状測定方法。 - 研磨パッドの表面の複数の箇所で、前記研磨パッドからの反射光の強度分布を取得する工程と、
前記複数の箇所で取得された複数の前記強度分布から前記研磨パッドの表面性状を間接的に示す波長構成比を算出する工程と、
前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程を備え、
前記研磨パッドからの反射光の強度分布を取得する工程は、
前記研磨パッドの表面にレーザ光を照射し、
前記研磨パッドからの反射光を受光する工程を含む、研磨パッドの表面性状判定方法。 - 前記複数の箇所で取得された複数の前記強度分布から前記研磨パッドの表面性状を間接的に示す波長構成比を算出する工程は、複数の前記強度分布のそれぞれから、波長構成比をそれぞれ算出することによって、複数の波長構成比を算出する工程を含む、請求項9に記載の研磨パッドの表面性状判定方法。
- 前記複数の箇所で取得された複数の前記強度分布から前記研磨パッドの表面性状を間接的に示す波長構成比を算出する工程は、前記複数の強度分布を平均化し、平均化された反射光の強度分布から、前記波長構成比を算出する工程を含む、請求項9に記載の研磨パッドの表面性状判定方法。
- 前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程は、前記算出された複数の波長構成比が予め定められた基準範囲内にあるか否かを確認し、前記算出された複数の波長構成比の全てが予め定められた基準範囲内にあるときに、前記研磨パッドの表面性状が良好であると判定する工程を含む、請求項10に記載の研磨パッドの表面性状判定方法。
- 前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程は、前記算出された複数の波長構成比の平均値を算出し、前記平均値と予め定められたしきい値を比較し、かつ前記算出された複数の波長構成比が予め定められた基準範囲内にあるか否かを確認し、前記平均値が前記しきい値よりも小さく、かつ前記算出された複数の波長構成比の全てが前記基準範囲内にあるときに前記研磨パッドの表面性状が良好であると判定する工程を含む、請求項10に記載の研磨パッドの表面性状判定方法。
- 前記算出された波長構成比に基づいて、前記研磨パッドの表面性状の良否を判定する工程は、前記算出された複数の波長構成比の平均値を算出し、前記平均値と予め定められたしきい値を比較し、かつ前記算出された複数の波長構成比が予め定められた基準範囲内にあるか否かを確認し、前記平均値が前記しきい値よりも大きく、かつ前記算出された複数の波長構成比の全てが前記基準範囲内にあるときに前記研磨パッドの表面性状が良好であると判定する工程を含む、請求項10に記載の研磨パッドの表面性状判定方法。
- 前記研磨パッドの表面性状が良好であると判定した場合、前記研磨パッドのブレークインを終了する工程をさらに含む、請求項9乃至14のいずれか一項に記載の研磨パッドの表面性状判定方法。
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CN202280010809.5A CN116745067A (zh) | 2021-01-21 | 2022-01-05 | 研磨垫的表面性状测量装置、研磨垫的表面性状测量方法及研磨垫的表面性状判定方法 |
US18/272,941 US20240075579A1 (en) | 2021-01-21 | 2022-01-05 | Surface property measuring apparatus for polishing pad, surface property measuring method for polishing pad, and surface property judging method for polishing pad |
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