Optical film thickness measuring device and polishing device

Abstract

The present application provides an optical film thickness measuring device and a polishing device capable of eliminating the influence of fluid flow on an optical fiber cable when a fluid such as pure water flows through a through-hole of a polishing pad, thereby achieving high film thickness measurement accuracy. The optical film thickness measuring device includes a light projecting optical fiber cable (51) connected to a light source (44), a light receiving optical fiber cable (52) that receives reflected light from a workpiece (W), a cable housing (55) that surrounds the light projecting optical fiber cable (31) and the light receiving optical fiber cable (32), and a flow path structure (58) that forms a fluid flow path (57) adjacent to the light projecting optical fiber cable (31) and the light receiving optical fiber cable (32). The light projecting optical fiber cable (31) and the light receiving optical fiber cable (32) are supported by at least one of the cable housing (55) and the flow path structure (58).

Description

Technical Field

[0001] This invention relates to an optical film thickness measuring device for measuring the film thickness of workpieces used in the manufacture of semiconductor components such as wafers, substrates, and panels, and more particularly to an optical film thickness measuring device that measures the film thickness of a workpiece while grinding it on a grinding pad. Background Technology

[0002] Typically, wafer polishing utilizes a chemical mechanical polishing (CMP) apparatus. This CMP apparatus is configured to polish the wafer surface by supplying polishing slurry to a polishing pad attached to a polishing table and bringing the wafer into sliding contact with the polishing pad. Wafer polishing ends when the thickness of the film (insulating film, metal film, silicon layer, etc.) constituting its surface reaches a predetermined target value. Therefore, the film thickness is measured during wafer polishing.

[0003] As an example of a film thickness measurement device, there exists an optical film thickness measurement device that measures film thickness by guiding light to the surface of a wafer and analyzing the optical information contained in the reflected light from the wafer. This optical film thickness measurement device includes a light-emitting fiber optic cable and a light-receiving fiber optic cable disposed within a polishing stage. Light emitted from the light-emitting fiber optic cable passes through a through-hole in the polishing pad and is guided to the wafer; reflected light from the wafer again passes through the through-hole and reaches the light-receiving fiber optic cable. The optical film thickness measurement device determines the film thickness of the wafer based on the spectrum of the reflected light received by the light-receiving fiber optic cable.

[0004] In wafer polishing, polishing slurry is supplied to the polishing pad. The slurry flows into the vias of the polishing pad, obstructing light travel. Therefore, to ensure light flow, pure water is supplied from inside the polishing stage into the vias. The vias are filled with pure water, and the polishing slurry and debris that have entered the vias are drained along with the pure water through a drainage line. The flow of pure water formed in the vias ensures light flow, enabling high-precision film thickness measurement.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2001-165627

[0008] However, as pure water flows toward the through-holes of the polishing pad, it comes into contact with the optical fiber cables for projection and reception, which are located within the polishing stage. This flow of pure water may cause displacement or vibration of the optical fiber cables for projection and reception. Such displacement or vibration can lead to changes in the spectrum of the reflected light. Recently, there has been a growing demand for high precision in wafer thickness measurement, and conventional optical thickness measurement devices may not be able to meet these requirements. Summary of the Invention

[0009] Therefore, this invention provides an optical film thickness measurement device that eliminates the influence of fluid flow on optical fiber cables when fluids such as pure water flow through the through-holes of a polishing pad, thereby achieving high film thickness measurement accuracy. Furthermore, this invention provides a polishing apparatus equipped with such an optical film thickness measurement device.

[0010] Technical means for solving technical problems

[0011] In one embodiment, an optical film thickness measuring device is provided for a grinding apparatus disposed on a workpiece, comprising: a light source; a light-emitting fiber optic cable connected to the light source; a light-receiving fiber optic cable receiving reflected light from the workpiece; a beam splitter measuring the intensity of the reflected light at each wavelength; a data processing unit calculating the film thickness of the workpiece based on the measured intensity data of the reflected light; a cable housing surrounding the light-emitting fiber optic cable and the light-receiving fiber optic cable; and a flow path structure forming a fluid flow path adjacent to the light-emitting fiber optic cable and the light-receiving fiber optic cable, wherein the light-emitting fiber optic cable and the light-receiving fiber optic cable are supported by at least one of the cable housing and the flow path structure.

[0012] In one embodiment, the tip portion of each of the optical fiber cable for transmitting light and the optical fiber cable for receiving light contacts at least one of the cable housing and the flow path structure.

[0013] In one embodiment, the optical fiber cable for transmitting light and the optical fiber cable for receiving light are joined together by an adhesive.

[0014] In one embodiment, the optical fiber cable for transmitting light and the optical fiber cable for receiving light are fixed to at least one of the cable housing and the flow path structure by an adhesive.

[0015] In one embodiment, the optical fiber cable for transmitting light and the optical fiber cable for receiving light are sandwiched between the cable housing and the flow path structure.

[0016] In one embodiment, the optical fiber cable for transmitting light and the optical fiber cable for receiving light are held together by a filler material that fills the space between the cable housing and the flow path structure.

[0017] In one embodiment, the optical film thickness measuring device further comprises a buffer tank connected to the flow path structure, the fluid flow path being in communication with the interior of the buffer tank.

[0018] In one embodiment, a grinding apparatus is provided, comprising: a grinding table for supporting a grinding pad; a grinding head configured to press a workpiece onto the grinding pad; and the aforementioned optical film thickness measuring device.

[0019] The effects of the invention

[0020] According to the present invention, the optical fiber cable for transmitting light and the optical fiber cable for receiving light are supported by at least one of the cable housing and the flow path structure. Therefore, even if a fluid such as pure water flows in the flow path, the flow of the fluid will not cause the optical fiber cable to shift or vibrate. As a result, the optical film thickness measuring device can measure the film thickness of the workpiece with high accuracy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating one embodiment of the grinding apparatus.

[0022] Figure 2 This is a diagram showing an example of the spectrum of reflected light from a workpiece.

[0023] Figure 3 yes Figure 1 An enlarged cross-sectional view of the cable housing and flow path structure shown.

[0024] Figure 4 yes Figure 3 A sectional view along line AA.

[0025] Figure 5 This is a cross-sectional view showing other embodiments of the configuration of fiber optic cables, cable housings, and flow path structures.

[0026] Figure 6 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0027] Figure 7 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0028] Figure 8 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0029] Figure 9 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0030] Figure 10 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0031] Figure 11 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0032] Figure 12This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0033] Figure 13 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0034] Figure 14 This is a cross-sectional view showing another embodiment of the configuration of the fiber optic cable, cable housing, and flow path structure.

[0035] Symbol Explanation

[0036] 1 Grinding head

[0037] 2 Grinding Pads

[0038] 2a Grinding surface

[0039] 3 grinding tables

[0040] 5 Grinding fluid supply nozzle

[0041] 6 motors

[0042] 10-head shaft

[0043] 17-connected structural components

[0044] 18 Grinding Head Motor

[0045] 19 Rotary Joint

[0046] 35 Motion Control Unit

[0047] 40 Optical Film Thickness Measurement Device

[0048] 41 Optical Sensor Head

[0049] 44 light sources

[0050] 47 beam splitter

[0051] 49 Data Processing Department

[0052] 51 Fiber Optic Cable for Flooding

[0053] 52 Optical fiber cable for receiving light

[0054] 55 cable housing

[0055] 57 Fluid flow path

[0056] 58 Flow Path Construction

[0057] 60 drainage channel

[0058] 61 through hole

[0059] 63 Fluid supply line

[0060] 64 drainage lines

[0061] 66 Fluid Supply Source

[0062] 70 buffer tank

[0063] 73 Filler Material

[0064] 75 second fluid flow path

[0065] 78 Drainage Structure Detailed Implementation

[0066] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0067] Figure 1 This is a schematic diagram illustrating one embodiment of the grinding apparatus. (As shown) Figure 1 As shown, the polishing apparatus includes: a polishing table 3 that supports the polishing pad 2, a polishing head 1 that presses workpieces such as wafers, substrates, and panels onto the polishing pad 2, a polishing fluid supply nozzle 5 that supplies polishing fluid (e.g., slurry) to the polishing surface 2a of the polishing pad 2, and a table motor 6 that rotates the polishing table 3.

[0068] The grinding head 1 is connected to the head shaft 10, and the grinding head 1 can rotate together with the head shaft 10. The head shaft 10 is connected to the grinding head motor 18 via a drive belt or other connecting structure 17, and the head shaft 10 rotates through the grinding head motor 18. By rotating the head shaft 10, the grinding head 1 rotates in the direction indicated by the arrow. The table shaft 3a of the grinding table 3 is connected to the table motor 6, and the table motor 6 is configured to rotate the grinding table 3 and the grinding pad 2 in the direction indicated by the arrow.

[0069] The grinding apparatus includes an action control unit 35 that controls the movement of the grinding apparatus. The action control unit 35 is comprised of at least one computer. The action control unit 35 includes a storage device 35a for storing programs and an arithmetic unit 35b for performing calculations based on the commands contained in the program. The storage device 35a includes a main storage device such as random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) or a solid-state drive (SSD). Examples of the arithmetic unit 35b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific structure of the action control unit 35 is not limited to these examples.

[0070] The grinding apparatus includes an optical film thickness measuring device 40 for measuring the film thickness of a workpiece W. The optical film thickness measuring device 40 includes an optical sensor head 41, a light source 44, a beam splitter 47, and a data processing unit 49. The optical sensor head 41, the light source 44, and the beam splitter 47 are mounted on a grinding table 3, which rotates integrally with the grinding pad 2. The optical sensor head 41 is positioned across the surface of the workpiece W on the grinding pad 2 each time the grinding table 3 and the grinding pad 2 complete one rotation. The optical sensor head 41 is connected to the light source 44 and the beam splitter 47, and the beam splitter 47 is connected to the data processing unit 49.

[0071] Light source 44 sends light to optical sensor head 41, which then emits light towards workpiece W. Optical sensor head 41 receives reflected light from workpiece W and sends it to beam splitter 47. Beam splitter 47 decomposes the reflected light according to its wavelength and measures the intensity of the reflected light at each wavelength. Beam splitter 47 sends the intensity measurement data of the reflected light to data processing unit 49. Data processing unit 49 generates a spectrum of the reflected light based on the intensity measurement data. This spectrum represents the relationship between the intensity and wavelength of the reflected light, and the shape of the spectrum varies according to the film thickness of workpiece W. Data processing unit 49 determines the film thickness of workpiece W based on the spectrum.

[0072] The workpiece W is ground as follows. While the grinding table 3 and grinding head 1 are moving towards... Figure 1 The grinding head rotates in the direction indicated by the arrow, supplying grinding fluid from the grinding fluid supply nozzle 5 to the grinding surface 2a of the grinding pad 2 on the grinding table 3. While the grinding head 1 rotates, it is pressed against the grinding surface 2a of the grinding pad 2 by the grinding head 1, with the grinding fluid present on the grinding pad 2. The surface of the workpiece W is ground by the chemical action of the grinding fluid, the abrasive particles contained in the grinding fluid, and the mechanical action of the grinding pad 2.

[0073] During the grinding of workpiece W, each time the grinding table 3 rotates once, the optical sensor head 41 traverses the surface of workpiece W on the grinding pad 2 while irradiating light onto multiple measurement points on workpiece W and receiving reflected light from workpiece W. The data processing unit 49 determines the film thickness of workpiece W based on the measurement data of the intensity of the reflected light.

[0074] The optical film thickness measuring device 40 will now be described in detail. The optical film thickness measuring device 40 includes: a light-projecting fiber optic cable 51 that guides light emitted from a light source 44 to the surface of a workpiece W; and a light-receiving fiber optic cable 52 that receives reflected light from the workpiece W and sends it to a beam splitter 47. The tips of the light-projecting fiber optic cable 51 and the light-receiving fiber optic cable 52 are located within the polishing table 3. The tips of the light-projecting fiber optic cable 51 and the light-receiving fiber optic cable 52 constitute an optical sensor head 41 that guides light to the surface of the workpiece W and receives reflected light from the workpiece W. The other end of the light-projecting fiber optic cable 51 is connected to the light source 44, and the other end of the light-receiving fiber optic cable 52 is connected to the beam splitter 47. The beam splitter 47 is configured to decompose the reflected light from the workpiece W according to wavelength and measure the intensity of the reflected light across a predetermined wavelength range.

[0075] The polishing table 3 has a drainage path 60 with an opening on its upper surface. The polishing pad 2 has a through hole 61 located at a position corresponding to the optical sensor head 41 and the drainage path 60. The optical sensor head 41 and the drainage path 60 communicate with the through hole 61, which is open on the polishing surface 2a. The optical sensor head 41, which is composed of the tip of the light-emitting fiber optic cable 51 and the tip of the light-receiving fiber optic cable 52, is located below the through hole 61.

[0076] The light source 44 uses a pulsed light source such as a xenon flash lamp. The fiber optic cable 51 is a light transmission unit that guides the light emitted by the light source 44 to the surface of the workpiece W. The tips of the fiber optic cable 51 and the fiber optic cable 52 are located inside the polishing table 3, near the polished surface of the workpiece W. The optical sensor head 41, formed by the tips of the fiber optic cables 51 and 52, is configured to face the workpiece W held in the polishing head 1. As the polishing table 3 rotates, light illuminates multiple measurement points on the workpiece W. In this embodiment, only one optical sensor head 41 is provided, but multiple optical sensor heads 41 may also be provided.

[0077] During the grinding of workpiece W, light passes through the through-hole 61 from the optical sensor head 41 and is guided to workpiece W. Reflected light from workpiece W passes through the through-hole 61 and is received by the optical sensor head 41. The spectrometer 47 measures the intensity of reflected light at each wavelength across a predetermined wavelength range and sends the obtained measurement data to the data processing unit 49. This measurement data is a film thickness signal that varies according to the film thickness of workpiece W. The data processing unit 49 generates a spectrum representing the intensity of light at each wavelength based on the measurement data, and then determines the film thickness of workpiece W based on the spectrum.

[0078] Figure 2 This is a diagram showing an example of the spectrum of reflected light. Figure 2The vertical axis represents the intensity of the reflected light, and the horizontal axis represents the frequency of the reflected light. The spectrum of this reflected light varies according to the thickness of the film on the workpiece W. Therefore, the data processing unit 49 can determine the film thickness of the workpiece W based on the spectrum of the reflected light. The method for determining the film thickness of the workpiece W based on the spectrum of the reflected light uses a known method. For example, the data processing unit 49 performs a Fourier transform on the spectrum of the reflected light and determines the film thickness based on the resulting frequency spectrum. In other examples, the data processing unit 49 determines a reference spectrum whose shape most closely approximates the spectrum of the reflected light and determines the film thickness associated with that determined reference spectrum.

[0079] The optical film thickness measuring device 40 includes: a cable housing 55 surrounding a light-emitting fiber optic cable 51 and a light-receiving fiber optic cable 52; and a flow path structure 58 forming a fluid flow path 57 adjacent to the light-emitting and light-receiving fiber optic cables 51 and 52. The cable housing 55 and the flow path structure 58 are disposed within a grinding table 3. The fluid flow path 57 is connected to a fluid supply line 63, and the drainage flow path 60 is connected to a drainage line 64. During the grinding of the workpiece W, a fluid such as pure water is supplied to the fluid flow path 57 and the through-hole 61 via the fluid supply line 63, filling the fluid flow path 57 and the through-hole 61. The fluid further flows from the through-hole 61 into the drainage flow path 60 and is discharged through the drainage line 64. The grinding fluid and the polishing slurry are discharged together, thereby ensuring the optical path.

[0080] Fluid supply line 63 and drainage line 64 are connected to rotary joint 19 and extend within grinding table 3. Rotary joint 19 is connected to the table shaft 3a of grinding table 3. One end of fluid supply line 63 is connected to fluid flow path 57 of flow path structure 58. The other end of fluid supply line 63 is connected to fluid supply source 66. In this embodiment, pure water, an example of a light-transmitting liquid, is used as the fluid, but the fluid can be other light-transmitting liquids, or it can be air, inactive gas, or other gases. Fluid supply source 66 can be a pure water supply source, which serves as an equipment supply source in a factory equipped with grinding devices.

[0081] Figure 3 yes Figure 1 The enlarged cross-sectional view of the cable housing 55 and the flow path structure 58 shown is shown. Figure 4 yes Figure 3 A sectional view along line AA. (e.g.) Figure 3 and Figure 4 As shown, the top ends of the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are located inside the cable housing 55. Furthermore, a flow path structure 58, which has a fluid flow path 57 inside, is also located inside the cable housing 55. The optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are disposed outside the flow path structure 58, which is disposed inside the cable housing 55.

[0082] The flow path structure 58 is connected to the buffer tank 70. More specifically, the buffer tank 70 is connected to the lower end of the flow path structure 58, and the fluid flow path 57 communicates with the interior of the buffer tank 70. The fluid supply line 63 is connected to the buffer tank 70. Therefore, the fluid flow path 57 is connected to the fluid supply line 63 via the buffer tank 70. Fluid (e.g., pure water) is temporarily stored in the buffer tank 70 and then flows into the fluid flow path 57. The buffer tank 70 has the function of stabilizing the flow rate of the fluid flowing into the fluid flow path 57.

[0083] like Figure 4 As shown, the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are supported (in contact) on both the cable housing 55 and the flow path structure 58. Specifically, the tips of the optical fiber cables 51 and 52 are in contact with both the cable housing 55 and the flow path structure 58. Therefore, the optical fiber cables 51 and 52 will not be displaced or vibrate due to the flow of fluid discharged from the fluid flow path 57. In particular, in this embodiment, the tips of the optical fiber cables 51 and 52 are sandwiched between the inner surface of the cable housing 55 and the outer surface of the flow path structure 58. With this configuration, the positions of the optical fiber cables 51 and 52 (especially the positions of their tips) can be firmly fixed.

[0084] In this embodiment, the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are disposed outside the flow path structure 58 that forms a fluid flow path 57 for the flow of fluid (e.g., pure water). Therefore, the fluid flowing in the fluid flow path 57 does not come into contact with these optical fiber cables 51 and 52. As a result, displacement or vibration of the optical fiber cables 51 and 52 (especially their tips) can be reliably prevented.

[0085] In this embodiment, the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are joined together by an adhesive (not shown). In particular, the tip portions of the optical fiber cable 51 for transmitting light and the tip portions of the optical fiber cable 52 for receiving light are joined together by an adhesive. By configuring it in this way, one of the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light constrains the other, thereby making it difficult for the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light to shift or vibrate.

[0086] Multiple fiber optic cables 51 for transmitting light and multiple fiber optic cables 52 for receiving light can be installed. For example, Figure 5 As shown, to increase the amount of light guiding the workpiece W, multiple optical fiber cables 51 for projecting light can be installed. Multiple optical fiber cables 52 for receiving light can also be installed.

[0087] The fiber optic cable 51 for transmitting light and the fiber optic cable 52 for receiving light (particularly their tips) can also be secured to one or both of the cable housing 55 and the flow path structure 58 using adhesive (not shown). For example, the fiber optic cable 51 for transmitting light and the fiber optic cable 52 for receiving light can also be secured to the inner surface of the cable housing 55 using adhesive. In this case, the fiber optic cable 51 for transmitting light and the fiber optic cable 52 for receiving light may not be in contact with the flow path structure 58. In other examples, the fiber optic cable 51 for transmitting light and the fiber optic cable 52 for receiving light can also be secured to the outer surface of the flow path structure 58 using adhesive. In this case, the fiber optic cable 51 for transmitting light and the fiber optic cable 52 for receiving light may also not be in contact with the cable housing 55.

[0088] In one implementation, such as Figure 6 As shown, the fiber optic cable 51 for transmitting light and the fiber optic cable 52 for receiving light (especially their tips) can also be held by a filler material 73 that fills the space between the cable housing 55 and the flow path structure 58. Figure 6 In the illustrated embodiment, the filler material 73 fills the space between the inner surface of the cable housing 55 and the outer surface of the flow path structure 58. Examples of filler material 73 include materials with airtightness and water resistance, such as putty and sealing materials. The filler material 73 can hold the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light and fix their positions.

[0089] In one implementation, such as Figure 7 As shown, to increase the fluid flow rate, in addition to the fluid flow path (or first fluid flow path) 57 within the flow path structure 58, a second fluid flow path 75 for the fluid (e.g., pure water) can also be formed between the cable housing 55 and the flow path structure 58. Figure 7 In the embodiment shown, the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are preferably sandwiched between the cable housing 55 and the flow path structure 58, or fixed to one or both of the cable housing 55 and the flow path structure 58 by an adhesive.

[0090] Figure 8 This is a cross-sectional view showing another embodiment of the arrangement of the optical fiber cable 51 for transmitting light, the optical fiber cable 52 for receiving light, the cable housing 55, and the flow path structure 58. The structure of this embodiment, unless otherwise specified, is based on... Figure 3 and Figure 4 The implementation methods have already been described, so repeated descriptions are omitted.

[0091] exist Figure 8 In the embodiment shown, the drainage line 64 of the fluid (see reference) Figure 1A drainage structure 78 is disposed within the cable housing 55. The drainage structure 78 has a drainage path 60 internally, and a drainage line 64 communicates with the drainage path 60. The drainage structure 78 contacts the inner surface of the cable housing 55, and the drainage path structure 58 contacts the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light. These optical fiber cables 51 and 52 are sandwiched between the cable housing 55, the drainage path structure 58, and the drainage structure 78. Therefore, the optical fiber cables 51 and 52 (particularly their tips) are in contact (supported) with the inner surface of the cable housing 55, the outer surface of the drainage path structure 58, and the outer surface of the drainage structure 78. Figure 9 As shown, the cable housing 55 can also have an elliptical cross-section.

[0092] Figure 10 This is a cross-sectional view showing another embodiment of the arrangement of the optical fiber cable 51 for transmitting light, the optical fiber cable 52 for receiving light, the cable housing 55, and the flow path structure 58. The structure of this embodiment, unless otherwise specified, is based on... Figure 8 The implementation methods have already been described, therefore repeated descriptions are omitted. Figure 10 In the illustrated embodiment, the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are each surrounded by two first cable housings 55A having a polygonal cross-section. The optical fiber cable 51 for transmitting light, the optical fiber cable 52 for receiving light, and the first cable housings 55A are further surrounded by a second cable housing 55B having a circular cross-sectional shape. The two first cable housings 55A are in surface contact with each other, and the inner surface of the second cable housing 55B is in contact with the outer surfaces of the flow path structure 58 and the drainage structure 78. The flow path structure 58 and the drainage structure 78 are disposed between the outer surface of the first cable housing 55A and the inner surface of the second cable housing 55B.

[0093] Figure 11 This is a cross-sectional view showing another embodiment of the arrangement of the optical fiber cable 51 for transmitting light, the optical fiber cable 52 for receiving light, the cable housing 55, and the flow path structure 58. The structure of this embodiment, unless otherwise specified, is based on... Figure 10 The implementation methods have already been described, therefore repeated descriptions are omitted. Figure 11 In the embodiment shown, the flow path structure 58 and the drainage structure 78 have polygonal cross-sections, and the second cable housing 55B has an elliptical cross-sectional shape.

[0094] like Figure 12 and Figure 13 As shown, the cable housing 55 can also have a rectangular cross-section. Figure 12 In the illustrated embodiment, the cable housing 55 has a rectangular cross-sectional shape. Figure 13In the embodiment shown, the cable housing 55 has a rectangular cross-sectional shape, and the flow path structure 58 and the drainage structure 78 also have rectangular cross-sectional shapes.

[0095] like Figure 14 As shown, one or both of the optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light can also be bundled optical cables. Figure 14 In the illustrated embodiment, the optical fiber cable 51 for transmitting light is a bundled optical cable comprising a plurality of optical fiber cables 51a. The plurality of optical fiber cables 51a constituting the optical fiber cable 51 are arranged around the optical fiber cable 52 for receiving light. The optical fiber cable 51 for transmitting light and the optical fiber cable 52 for receiving light are surrounded by a first cable sheath 55A having a circular cross-section. The optical fiber cable 51 for transmitting light, the optical fiber cable 52 for receiving light, and the first cable sheath 55A are further surrounded by a second cable sheath 55B having a rectangular cross-section. The second cable sheath 55B may also have other cross-sectional shapes such as an ellipse. In one embodiment, the optical fiber cable 52 for receiving light may also be a bundled optical cable.

[0096] The above-described embodiments can be appropriately combined. For example, additionally, refer to... Figure 6 and Figure 7 The filler material 73 described can also be applied to Figures 8-13 The implementation method shown.

[0097] The embodiments described above are intended to enable those skilled in the art to implement the present invention. Various modifications of the above embodiments can obviously be implemented by those skilled in the art, and the technical concept of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is interpreted as encompassing the maximum scope of the technical concept as defined by the claimed scope.

Claims

1. An optical film thickness measuring device, disposed in a grinding device for a workpiece, characterized in that, have: light source; A fiber optic cable for projecting light, which is connected to the light source; A light-receiving fiber optic cable that receives reflected light from a workpiece; A beam splitter that measures the intensity of the reflected light at each wavelength; The data processing unit calculates the film thickness of the workpiece based on the measured data of the intensity of the reflected light. A cable housing that surrounds the optical fiber cable for transmitting light and the optical fiber cable for receiving light; as well as A flow path structure that forms a fluid flow path adjacent to the optical fiber cable for transmitting light and the optical fiber cable for receiving light. The optical fiber cable for transmitting light and the optical fiber cable for receiving light are in contact with the inner surface of the cable housing and the outer surface of the flow path structure, and are supported by both the cable housing and the flow path structure.

2. The optical film thickness measuring device according to claim 1, characterized in that, The top ends of the optical fiber cable for transmitting light and the optical fiber cable for receiving light are in contact with the cable housing and the flow path structure.

3. The optical film thickness measuring device according to claim 1 or 2, characterized in that, The optical fiber cable for transmitting light and the optical fiber cable for receiving light are joined together with an adhesive.

4. The optical film thickness measuring device according to claim 1 or 2, characterized in that, The optical fiber cable for transmitting light and the optical fiber cable for receiving light are fixed to the cable shell and the flow path structure by adhesive.

5. The optical film thickness measuring device according to claim 1 or 2, characterized in that, The optical fiber cable for transmitting light and the optical fiber cable for receiving light are sandwiched between the cable shell and the flow path structure.

6. The optical film thickness measuring device according to claim 5, characterized in that, The optical fiber cable for transmitting light and the optical fiber cable for receiving light are held together by a filling material that fills the space between the cable housing and the flow path structure.

7. The optical film thickness measuring device according to claim 1 or 2, characterized in that, The optical film thickness measuring device also includes a buffer tank connected to the flow path structure, and the fluid flow path is in communication with the interior of the buffer tank.

8. The optical film thickness measuring device according to claim 1, characterized in that, It also features a drainage structure with internal drainage channels. The optical fiber cable for projecting light and the optical fiber cable for receiving light are in contact with the outer surface of the drainage structure.

9. A grinding apparatus, characterized in that, have: A grinding table used to support the grinding pad; A grinding head configured to press a workpiece onto the grinding pad; and The optical film thickness measuring device as described in any one of claims 1 to 8.

10. An optical film thickness measuring device, disposed in a grinding device for a workpiece, characterized in that, have: light source; A fiber optic cable for projecting light, which is connected to the light source; A light-receiving fiber optic cable that receives reflected light from a workpiece; A beam splitter that measures the intensity of the reflected light at each wavelength; The data processing unit calculates the film thickness of the workpiece based on the measured data of the intensity of the reflected light. A first cable housing surrounds the optical fiber cable for transmitting light and the optical fiber cable for receiving light, and has a circular cross-sectional shape. A flow path structure that forms a fluid flow path adjacent to the first cable housing; Drainage structure; as well as A second cable housing surrounds the flow path structure, the first cable housing, and the drainage structure. The flow path structure and the drainage structure are located on both sides of the first cable housing. The first cable housing is supported by the flow path structure, the drainage structure, and the second cable housing. The optical fiber cable for transmitting light is a bundled optical cable comprising multiple optical fibers surrounding the optical fiber cable for receiving light.

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