Processing method and processing device

Abstract

To provide a processing method and a processing device which, in chemical mechanical polishing for processing synthetic quartz glass or the like, can improve the surface roughness of a processed surface in a short period of time despite a simple structure, and can achieve highly efficient processing.SOLUTION: A processing device 1 has a polishing surface plate 2, and a sample holder 4 for holding synthetic quartz glass 3, and has a slurry supply unit 6 for dropping polishing slurry 60 onto a polishing pad 5 on the upper surface of the polishing surface plate 2, and a slurry supply bottle 7 is filled with the polishing slurry 60 containing cerium oxide abrasive grains (CeO2) therein. An ozone gas supply unit 8 for supplying ozone gas G to the polishing slurry 60 is provided inside the slurry supply bottle 7. An ultraviolet light irradiation unit 9 for irradiating the polishing slurry 60 with ultraviolet light L is provided inside the slurry supply bottle 7. The polishing slurry 60 supplied with the ozone gas G and irradiated with the ultraviolet light L is dropped from the slurry supply unit 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a processing method and processing apparatus, and more particularly to a processing method and processing apparatus that can improve the surface roughness of a processed surface in a short time while having a simple configuration and can achieve highly efficient processing in chemical mechanical polishing for processing synthetic quartz glass and the like. [Background technology]

[0002] Glass materials are used as raw materials for a variety of applications, such as optical fibers, camera lenses, and liquid crystal displays, due to their excellent properties, including optical properties, chemical stability, heat resistance, and electrical insulation.

[0003] Furthermore, in order to use glass materials for such various applications, they are polished with high precision, typically by chemical mechanical polishing.

[0004] Chemical mechanical polishing is a technique that uses the surface chemical action of the abrasive (abrasive grains) itself, or the action of the chemical components contained in the slurry, to increase the mechanical polishing (surface removal) effect caused by the relative movement between the slurry and the object to be polished, resulting in an extremely smooth polished surface.

[0005] Chemical mechanical polishing is also used to polish and planarize the surfaces of semiconductor substrates such as SiC substrates and gallium nitride (GaN) substrates (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-107993 Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional chemical mechanical polishing is insufficient in efficiency when polishing glass materials that will become precision glass components, and there has been a demand for improving the processing efficiency of the polishing process in order to improve productivity.

[0008] The present invention has been devised in view of the above points, and aims to provide a processing method and processing apparatus that can improve the surface roughness of the processed surface in a short time while having a simple configuration and that can achieve highly efficient processing in chemical mechanical polishing for processing synthetic quartz glass and the like. [Means for solving the problem]

[0009] [Processing method] In order to achieve the above object, the processing method of the present invention includes the steps of irradiating an abrasive slurry containing abrasive grains with ultraviolet light and supplying ozone gas, dropping the abrasive slurry onto a predetermined abrasive pad provided on a polishing table, and displacing the predetermined abrasive pad while it is in contact with the workpiece.

[0010] Here, a polishing slurry containing abrasive grains is dropped onto a specified polishing pad placed on the polishing table, and the specified polishing pad is displaced while in contact with the workpiece, whereby the surface chemical action of the abrasive grains or the chemical components contained in the slurry act, causing mechanical polishing (surface removal) due to the relative movement between the slurry and the workpiece, thereby processing the workpiece.

[0011] In addition, by irradiating ultraviolet light onto a polishing slurry containing abrasive grains and dropping the polishing slurry onto a specified polishing pad placed on a polishing table, the organic matter adhering to the surface of the abrasive grains can be removed by the ultraviolet light, thereby improving the surface chemical action of the abrasive grains.

[0012] In addition, by supplying ozone gas to a polishing slurry containing abrasive grains and dropping the polishing slurry onto a specified polishing pad provided on a polishing table, the organic matter adhering to the surface of the abrasive grains can be removed by the ozone gas, thereby improving the surface chemical action of the abrasive grains.

[0013] In addition, by irradiating an abrasive slurry containing abrasive grains with ultraviolet light and supplying ozone gas, and then dropping the abrasive slurry onto a specified abrasive pad provided on a polishing table, organic matter adhering to the abrasive grain surface can be removed by the ultraviolet light and ozone gas, thereby further improving the surface chemical action of the abrasive grains.

[0014] In the present invention, a polishing slurry containing abrasive grains is dropped onto a specified polishing pad, and the polishing pad is displaced while in contact with the workpiece. The surface chemical action of the abrasive grains or the chemical components contained in the slurry act to cause mechanical polishing (surface removal) due to the relative movement between the slurry and the workpiece, thereby processing the workpiece.

[0015] In addition, by irradiating a polishing slurry containing abrasive grains with ultraviolet light and supplying ozone gas and dropping it onto a specified polishing pad, organic matter (dirt and impurities) adhering to the surface of the abrasive grains can be removed with the ultraviolet light and ozone gas, improving the surface chemical action of the abrasive grains and improving processing efficiency.

[0016] Furthermore, when the abrasive grains are cerium oxide abrasive grains, organic matter adhering to the surface of the cerium oxide abrasive grains can be removed with ultraviolet light and ozone gas, increasing the amount of hydroxyl groups exposed on the abrasive grain surface that act to polish the workpiece, thereby improving processing efficiency.

[0017] Furthermore, if the workpiece is made of any one of synthetic quartz glass, soda-lime glass, borosilicate glass, alkali-free glass, high-silica glass, fused quartz glass, other oxide-based glasses whose main component is silicon oxide, or silicon-based ceramics such as SiC and Si3N4, sufficiently stable processing of the workpiece is possible.

[0018] Furthermore, when vacuum ultraviolet light is irradiated onto a specified polishing pad, the surface of the specified polishing pad is made hydrophilic, thereby increasing the retention of abrasive grains in the specified polishing pad and improving processing efficiency.

[0019] [About the processing equipment] In addition, in order to achieve the above-mentioned object, the processing apparatus of the present invention comprises a polishing table, a predetermined polishing pad provided on the polishing table, a holding mechanism for holding the workpiece in contact with the predetermined polishing pad, a slurry supply unit for dripping a polishing slurry containing abrasive grains onto the predetermined polishing pad, an ultraviolet light irradiation unit for irradiating the polishing slurry with ultraviolet light, an ozone gas supply unit for supplying ozone gas to the polishing slurry, and a drive unit for displacing the predetermined polishing pad while the predetermined polishing pad is in contact with the workpiece.

[0020] Here, the polishing table, a specified polishing pad provided on the polishing table, a holding mechanism that holds the workpiece in contact with the specified polishing pad, a slurry supply unit that drips polishing slurry containing abrasive grains onto the specified polishing pad, and a drive unit that displaces the specified polishing pad while it is in contact with the workpiece, cause the surface chemical action of the abrasive grains or the chemical components contained in the slurry to act, resulting in mechanical polishing (surface removal) due to the relative movement between the slurry and the workpiece, thereby processing the workpiece.

[0021] In addition, the ultraviolet light irradiation unit irradiates the polishing slurry with ultraviolet light, and the organic matter adhering to the surface of the abrasive grains is removed by the ultraviolet light, thereby improving the surface chemical action of the abrasive grains.

[0022] In addition, an ozone gas supply unit supplies ozone gas to the polishing slurry, and the organic matter adhering to the surface of the abrasive grains is removed by the ozone gas, thereby improving the surface chemical action of the abrasive grains.

[0023] In addition, by using an ultraviolet light irradiation section that irradiates the polishing slurry with ultraviolet light and an ozone gas supply section that supplies ozone gas to the polishing slurry, organic matter adhering to the surface of the abrasive grains can be removed with ultraviolet light and ozone gas, thereby further improving the surface chemical action of the abrasive grains.

[0024] In the present invention, a polishing slurry containing abrasive grains is dropped onto a specified polishing pad, and the polishing pad is displaced while in contact with the workpiece. The surface chemical action of the abrasive grains or the chemical components contained in the slurry act to cause mechanical polishing (surface removal) due to the relative movement between the slurry and the workpiece, thereby processing the workpiece.

[0025] In addition, by irradiating a polishing slurry containing abrasive grains with ultraviolet light and supplying ozone gas and dropping it onto a specified polishing pad, organic matter (dirt and impurities) adhering to the surface of the abrasive grains can be removed with the ultraviolet light and ozone gas, improving the surface chemical action of the abrasive grains and improving processing efficiency.

[0026] Furthermore, when the abrasive grains are cerium oxide abrasive grains, organic matter adhering to the surface of the cerium oxide abrasive grains can be removed with ultraviolet light and ozone gas, increasing the amount of hydroxyl groups exposed on the abrasive grain surface that act to polish the workpiece, thereby improving processing efficiency.

[0027] Furthermore, if the workpiece is made of any one of synthetic quartz glass, soda-lime glass, borosilicate glass, alkali-free glass, high-silica glass, fused quartz glass, other oxide-based glasses whose main component is silicon oxide, or silicon-based ceramics such as SiC and Si3N4, sufficiently stable processing of the workpiece is possible.

[0028] Furthermore, when a vacuum ultraviolet light irradiation unit that irradiates a specified polishing pad with vacuum ultraviolet light is provided, the surface of the specified polishing pad can be made hydrophilic, increasing the retention of abrasive grains in the specified polishing pad and improving processing efficiency. [Effects of the Invention]

[0029] The processing method and processing apparatus to which the present invention is applied can improve the surface roughness of the processed surface in a short time using chemical mechanical polishing to process synthetic quartz glass, etc., while having a simple configuration, and can achieve highly efficient processing. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a schematic diagram for explaining a processing device according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a schematic diagram illustrating a processing device according to a second embodiment of the present invention. [Figure 3] This is the spectrum of the analysis results of the polishing slurry by FT-IR (Fourier transform infrared spectrophotometer). [Figure 4] 1 is a graph showing the relationship between processing time and the surface roughness of the synthetic quartz glass after processing for each processing time in Example 1 and Comparative Example 1. [Figure 5] (a) is data obtained by measuring the surface roughness of a portion of the processing area of ​​the synthetic quartz glass in Example 1 using a non-contact shape measuring device before processing began, and (b) is data obtained by measuring the surface roughness of a portion of the processing area of ​​the synthetic quartz glass in Example 1 using a non-contact shape measuring device 30 minutes after processing began. [Figure 6] 1 is a graph showing the processing efficiency of Example 1 and Comparative Example 1. [Figure 7] (a) is data obtained by measuring the surface roughness of a portion of the processing area of ​​the synthetic quartz glass before processing in Example 2 using a non-contact shape measuring device, and (b) is data obtained by measuring the surface roughness of a portion of the processing area of ​​the synthetic quartz glass after processing in Example 2 using a non-contact shape measuring device. [Figure 8] 1 is a graph showing the processing efficiency of Example 1, Example 2, Comparative Example 1, and Comparative Example 3. [Figure 9] 1 shows data on the hydrophilicity of the polishing pad surface, showing the contact angles of Comparative Example 1(a), Comparative Example 2(b), and Comparative Example 3(c). [Figure 10] 1 is a graph showing the relationship between processing time and the surface roughness of the synthetic quartz glass after processing for each processing time in Comparative Examples 1 to 3. [Figure 11](a) is data obtained by measuring the surface roughness of a portion of the processing area of ​​the synthetic quartz glass before processing began in Comparative Example 3 using a non-contact shape measuring device, and (b) is data obtained by measuring the surface roughness of a portion of the processing area of ​​the synthetic quartz glass after processing in Comparative Example 3 using a non-contact shape measuring device. [Figure 12] 1 is a graph showing the processing efficiency of Comparative Examples 1 to 3. DETAILED DESCRIPTION OF THE INVENTION

[0031] [First embodiment of the invention] An embodiment of the present invention (hereinafter referred to as "first embodiment of the present invention") will be described below. 1(a) and 1(b) are schematic diagrams for explaining a processing apparatus to which the present invention is applied. The processing apparatus 1 shown here has a polishing table 2 and a sample holder 4 that holds synthetic quartz glass 3. A replaceable polishing pad 5 is attached to the upper surface of the polishing table 2 (see FIG. 1(a)). The polishing pad 5 is made of nonwoven fabric. The synthetic quartz glass 3 is an example of a workpiece.

[0032] The processing apparatus 1 also has a slurry supply unit 6 that drops a polishing slurry 60 onto the polishing pad 5. The slurry supply unit 6 is connected to a slurry supply bottle 7 shown in FIG.

[0033] The slurry supply bottle 7 is filled with a polishing slurry 60 containing cerium oxide abrasive grains (CeO2). The slurry supply bottle 7 also has a stirrer 70 disposed therein.

[0034] An ozone gas supply unit 8 is provided inside the slurry supply bottle 7, which supplies ozone gas G to the polishing slurry 60. An ultraviolet light irradiation unit 9 is provided inside the slurry supply bottle 7, which irradiates ultraviolet light L onto the polishing slurry 60. That is, the polishing slurry 60 is supplied with ozone gas G and irradiated with ultraviolet light L, and then dripped from the slurry supply unit 6.

[0035] In addition, the polishing platen 2 is fixed to a rotation mechanism (not shown) whose rotation speed can be controlled, and the polishing platen 2 and the polishing pad 5 are configured to rotate together in the direction indicated by the symbol A in Figure 1(a) by rotation of this rotation mechanism.

[0036] The sample holder 4 is rotatable in the direction indicated by the symbol B in Figure 1(a) around a rotation axis (not shown) that is eccentric to the rotation axis of the polishing platen 2. The sample holder 4, holding the synthetic quartz glass 3, descends from above to a position where the synthetic quartz glass 3 comes into contact with the polishing pad 5. The symbol Y in the figure indicates the direction in which the load is applied.

[0037] In this processing device 1, polishing slurry 60 supplied from a slurry supply bottle 7 is dripped onto a polishing pad 5 attached to the upper surface of a circular polishing table 2 via a slurry supply section 6, and with the synthetic quartz glass 3, which is the workpiece, in contact with the upper surface of the polishing pad 5, the polishing table 2, polishing pad 5, and sample holder 4 each rotate, thereby polishing the workpiece.

[0038] In other words, the hydroxyl groups (-OH) on the surface of the cerium oxide abrasive grains contained in the polishing slurry 60 act on the silanol groups (Si-OH) on the surface of the synthetic quartz glass 3, a type of glass material, resulting in a chemical reaction on the surface of the synthetic quartz glass 3 that causes a dehydration condensation reaction, and mechanical polishing (surface removal) occurs due to the relative movement of the polishing slurry 60 and the synthetic quartz glass 3, thereby processing the synthetic quartz glass 3.

[0039] In addition, by supplying ozone gas G to the polishing slurry 60 inside the slurry supply bottle 7 and irradiating it with ultraviolet light L, organic matter (dust and impurities) adhering to the surface of the cerium oxide abrasive grains can be removed by the ultraviolet light and ozone gas, thereby increasing the amount of hydroxyl groups (-OH) exposed on the surface of the cerium oxide abrasive grains.

[0040] This increases the frequency of the dehydration condensation reaction on the surface of the synthetic quartz glass 3 caused by the cerium oxide abrasive grains, thereby improving the processing efficiency of the synthetic quartz glass 3.

[0041] In this embodiment, the workpiece held by the sample holder 4 is described using synthetic quartz glass 3 as an example, but the workpiece is not limited to synthetic quartz glass 3 and any glass material can be used. For example, it may be soda-lime glass, borosilicate glass, alkali-free glass, high-silica glass, fused silica glass, other oxide-based glasses containing silicon oxide as the main component, silicon-based ceramics such as SiC and Si3N4, etc.

[0042] A processing method using the processing device 1 configured as above will be described below. That is, an example of a processing method to which the present invention is applied will be described.

[0043] In one example of a processing method to which the present invention is applied, polishing slurry 60 is dropped onto polishing pad 5 from slurry supply unit 6 while polishing platen 2, polishing pad 5, and sample holder 4 are all rotated.

[0044] That is, while supplying polishing slurry 60 to the contact area between the polishing pad 5 and the synthetic quartz glass 3, the polishing pad 5 and the sample holder 4 are rotated, displacing the polishing pad 5 and the synthetic quartz glass 3 while they are in contact. This causes a dehydration condensation reaction on the surface of the synthetic quartz glass 3 due to the hydroxyl groups (-OH) on the surface of the cerium oxide abrasive grains, and mechanical polishing (surface removal) occurs due to the relative movement of the polishing slurry 60 and the synthetic quartz glass 3, thereby processing the synthetic quartz glass 3.

[0045] In addition, by supplying ozone gas G to the polishing slurry 60 inside the slurry supply bottle 7 and irradiating it with ultraviolet light L, organic matter (dust and impurities) adhering to the surface of the cerium oxide abrasive grains can be removed by the ultraviolet light and ozone gas, thereby increasing the amount of hydroxyl groups (-OH) exposed on the surface of the cerium oxide abrasive grains.

[0046] This increases the frequency of the dehydration condensation reaction on the surface of the synthetic quartz glass 3 caused by the cerium oxide abrasive grains, thereby improving the processing efficiency of the synthetic quartz glass 3.

[0047] [effect] The processing device and processing method to which the present invention is applied supply ozone gas to the polishing slurry and irradiate it with ultraviolet light, thereby removing organic matter adhering to the surface of the cerium oxide abrasive grains, increasing the frequency of dehydration condensation reactions on the surface of the workpiece caused by the cerium oxide abrasive grains, and improving the processing efficiency of the workpiece.

[0048] In this way, even with a simple configuration, it is possible to improve the processing efficiency of workpieces, particularly glass materials, in chemical mechanical polishing. Furthermore, the processing apparatus and processing method to which the present invention is applied can improve the surface roughness of the processed surface of the workpiece in a short period of time.

[0049] Furthermore, the processing apparatus to which the present invention is applied can be easily constructed by simply arranging the ozone gas supply unit and the ultraviolet light irradiation unit in an existing slurry supply bottle.

[0050] [Second embodiment of the invention] Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as "second embodiment of the present invention") will be described. The second embodiment of the present invention differs from the first embodiment of the present invention described above only in that a vacuum ultraviolet light irradiation unit 10, which will be described later, is provided, and other configurations are common to the processing apparatus 1. Therefore, the following description will focus on the differences from the first embodiment of the present invention, and the same reference numerals will be used for overlapping configurations, and detailed description thereof will be omitted.

[0051] 2(a) and 2(b) are schematic diagrams illustrating a processing apparatus to which the present invention is applied. The processing apparatus 1A shown here has a polishing platen 2 and a sample holder 4 that holds synthetic quartz glass 3. A replaceable polishing pad 5 is attached to the upper surface of the polishing platen 2 (see FIG. 2(a)).

[0052] The processing apparatus 1A also has a slurry supply unit 6 that drops a polishing slurry 60 onto the polishing pad 5. The slurry supply unit 6 is connected to a slurry supply bottle 7 shown in FIG.

[0053] The slurry supply bottle 7 is filled with a polishing slurry 60 containing cerium oxide abrasive grains (CeO2). The slurry supply bottle 7 also has a stirrer 70 disposed therein.

[0054] Further, an ozone gas supply unit 8 that supplies ozone gas G to the polishing slurry 60 is provided inside the slurry supply bottle 7. Further, an ultraviolet light irradiation unit 9 that irradiates the polishing slurry 60 with ultraviolet light L is provided inside the slurry supply bottle 7.

[0055] The processing apparatus 1A is also provided with a vacuum ultraviolet light irradiation unit 10 (see FIG. 2(a)) that irradiates the upper surface of the polishing pad 5 with vacuum ultraviolet light V. The vacuum ultraviolet light irradiation unit 10 is configured to be able to irradiate the upper surface of the polishing pad 5 with vacuum ultraviolet light having a wavelength of 172 nm.

[0056] In this processing apparatus 1A, polishing slurry 60 supplied from a slurry supply bottle 7 is dripped onto a polishing pad 5 attached to the upper surface of a circular polishing table 2 via a slurry supply section 6, and the workpiece, which is synthetic quartz glass 3, is in contact with the upper surface of the polishing pad 5, and the polishing table 2, polishing pad 5, and sample holder 4 are each rotated, thereby polishing the workpiece.

[0057] Furthermore, in the processing apparatus 1A, the surface of the polishing pad 5 can be made hydrophilic by irradiating the upper surface of the polishing pad 5 with vacuum ultraviolet light. This makes it easier for the polishing slurry 60 (cerium oxide abrasive grains) dropped onto the polishing pad 5 to be retained by the polishing pad 5, thereby improving the retention of the polishing slurry 60 on the polishing pad 5.

[0058] As a result, the polishing slurry 60 comes into contact with the synthetic quartz glass 3, which is the workpiece, more frequently, and the processing efficiency of the synthetic quartz glass 3 can be improved.

[0059] In addition, in the processing device 1A, ozone gas G is supplied to the polishing slurry 60 inside the slurry supply bottle 7, and ultraviolet light L is irradiated, so that organic matter (dust and impurities) adhering to the surface of the cerium oxide abrasive grains can be removed by the ultraviolet light and ozone gas, thereby increasing the amount of hydroxyl groups (-OH) exposed on the surface of the cerium oxide abrasive grains.

[0060] This increases the frequency of the dehydration condensation reaction on the surface of the synthetic quartz glass 3 caused by the cerium oxide abrasive grains, thereby improving the processing efficiency of the synthetic quartz glass 3.

[0061] In this embodiment, the workpiece held by the sample holder 4 is described using synthetic quartz glass 3 as an example, but the workpiece is not limited to synthetic quartz glass 3 and any glass material can be used. For example, it may be soda-lime glass, borosilicate glass, alkali-free glass, high-silica glass, fused silica glass, other oxide-based glasses containing silicon oxide as the main component, silicon-based ceramics such as SiC and Si3N4, etc.

[0062] A processing method using the processing apparatus 1A configured as above will be described below, that is, an example of a processing method to which the present invention is applied.

[0063] In one example of a processing method to which the present invention is applied, polishing slurry 60 is dropped onto polishing pad 5 from slurry supply unit 6 while polishing platen 2, polishing pad 5, and sample holder 4 are all rotated.

[0064] Furthermore, the upper surface of the polishing pad 5 is irradiated with vacuum ultraviolet light from a vacuum ultraviolet light irradiation unit 10 .

[0065] That is, by supplying polishing slurry 60 to the contact area between the polishing pad 5 and the synthetic quartz glass 3, and rotating the polishing pad 5 and the sample holder 4 while irradiating the upper surface of the polishing pad 5 with vacuum ultraviolet light, the polishing pad 5 and the synthetic quartz glass 3 are displaced while in contact with each other. This causes a dehydration condensation reaction on the surface of the synthetic quartz glass 3 due to the hydroxyl groups (-OH) on the surface of the cerium oxide abrasive grains, and mechanical polishing (surface removal) occurs due to the relative movement of the polishing slurry 60 and the synthetic quartz glass 3, thereby processing the synthetic quartz glass 3.

[0066] In addition, by irradiating the upper surface of the polishing pad 5 with vacuum ultraviolet light, the surface of the polishing pad 5 is made hydrophilic, improving the retention of the polishing slurry 60 on the polishing pad 5 and improving the processing efficiency of the synthetic quartz glass 3.

[0067] In addition, by supplying ozone gas G to the polishing slurry 60 inside the slurry supply bottle 7 and irradiating it with ultraviolet light L, organic matter (dust and impurities) adhering to the surface of the cerium oxide abrasive grains can be removed by the ultraviolet light and ozone gas, thereby increasing the amount of hydroxyl groups (-OH) exposed on the surface of the cerium oxide abrasive grains.

[0068] This increases the frequency of the dehydration condensation reaction on the surface of the synthetic quartz glass 3 caused by the cerium oxide abrasive grains, thereby improving the processing efficiency of the synthetic quartz glass 3.

[0069] [effect] The processing apparatus and processing method to which the present invention is applied irradiates the upper surface of a polishing pad with vacuum ultraviolet light, thereby making the surface of the polishing pad hydrophilic, improving the retention of polishing slurry on the polishing pad, and further improving the processing efficiency of the workpiece.

[0070] Furthermore, the processing device and processing method to which the present invention is applied can improve the surface roughness of the processed surface of the workpiece in a short period of time.

[0071] Furthermore, a processing apparatus to which the present invention is applied can be easily constructed by simply providing a vacuum ultraviolet light irradiation unit on the polishing pad and placing an ozone gas supply unit and an ultraviolet light irradiation unit on an existing slurry supply bottle.

[0072] Hereinafter, examples of the present invention will be described. Note that the examples shown here are merely examples and do not limit the present invention.

[0073] [Example 1] As the processing method of the examples of the present invention, processing was carried out under the following conditions. First, as the processing method of Example 1 of the present invention, synthetic quartz glass (Quartz (Φ50)) as a workpiece was pressed with a load of 2 kg onto a polishing pad made of nonwoven fabric (Suede type pad (540N-200)) attached on a polishing table, and the polishing table and polishing pad were rotated at a rotation speed of 60 rpm, and the sample holder was also rotated at a rotation speed of 60 rpm. In addition, inside the slurry supply bottle, 0.1 wt% polishing slurry (CeO2 / H2O) containing cerium oxide abrasive grains was supplied with 50 g / m2 of ozone gas from an ozone gas supply unit. 3 Ozone gas was supplied at 1 L / min, and ultraviolet light (wavelength 200-450 nm) was irradiated from the ultraviolet light irradiation unit. The polishing slurry after ozone gas supply and ultraviolet light irradiation was dripped onto the polishing pad from the slurry supply unit at a flow rate of 5 ml / min. Comparative Example 1 was prepared by the same method as in Example 1, except that no ozone gas was supplied by the ozone gas supply unit and no ultraviolet light was irradiated by the ultraviolet light irradiator.

[0074] In the apparatus configuration of the processing method of Example 1 and Comparative Example 1 described above, structural analysis was performed using FT-IR (Fourier transform infrared spectrophotometer) on the polishing slurry after processing in which ozone gas was supplied and ultraviolet light was irradiated, and on the unprocessed polishing slurry in which no ozone gas was supplied and no ultraviolet light was irradiated. Furthermore, for Example 1 and Comparative Example 1, the relationship between the processing time and the surface roughness of the synthetic quartz glass after processing for each processing time was confirmed. Furthermore, for Example 1 above, the surface roughness of the synthetic quartz glass before and after processing was measured and evaluated using a non-contact shape measuring device. Furthermore, the processing efficiency was confirmed for the above-mentioned examples and comparative examples.

[0075] Figure 3 shows the spectrum of the FT-IR analysis results, and Figure 4 shows a graph showing the relationship between processing time and the surface roughness of synthetic quartz glass after processing for each processing time.In Figure 3, the vertical axis indicates transmittance, and the horizontal axis indicates wavenumber.In addition, of the two spectra, in the regions indicated by symbols A and B, the spectrum located on the upper side is the spectrum of untreated polishing slurry without supplying ozone gas and without irradiating ultraviolet light, and the spectrum located on the lower side is the spectrum of polishing slurry after processing with supplying ozone gas and irradiating ultraviolet light.In addition, in Figure 4, the vertical axis indicates surface roughness, and the horizontal axis indicates processing time.

[0076] As shown in Figure 3, in the region of spectrum indicated by symbol A and symbol B, there is a change in the peak between the spectrum of the polishing slurry that is treated by supplying ozone gas and irradiating ultraviolet light, and the spectrum of the polishing slurry that is not treated by supplying ozone gas and irradiating ultraviolet light.The region indicated by symbol A and symbol B is the region that is caused by hydroxyl group (-OH), and from the change in this peak, it is confirmed that by supplying ozone gas to the polishing slurry and irradiating ultraviolet light, organic matter is removed from the surface of the cerium oxide abrasive grain that is contained in the polishing slurry, and hydroxyl group (-OH) is increased on the surface.

[0077] 4, in Example 1, a significant improvement in surface roughness was observed from the start of processing, and 30 minutes after the start of processing, the surface roughness reached a finishing value of Ra: 0.5 nm or less. On the other hand, in Comparative Example 1, it took 180 minutes from the start of processing for the surface roughness to reach a finishing value of Ra: 0.5 nm or less.

[0078] Figure 5(a) shows the surface roughness of a portion of the processing area of ​​the synthetic quartz glass before processing began in Example 1, and Figure 5(b) shows the surface roughness of a portion of the processing area of ​​the synthetic quartz glass 30 minutes after processing began in Example 1.

[0079] As shown in Figures 5(a) and 5(b), the surface roughness of part of the processed region of the synthetic quartz glass was sufficiently improved by the processing of Example 1. In addition, in the result of Figure 5(a), the arithmetic mean roughness (Ra) value in the measurement range of the processed surface of the synthetic quartz glass before the start of processing was 3.028 nm. In the result of Figure 5(b), the arithmetic mean roughness (Ra) value in the measurement range of the processed surface of the synthetic quartz glass 30 minutes after the start of processing of Example 1 was 0.362 nm.

[0080] Figure 6 shows the results of the processing efficiency for Example 1 and Comparative Example 1. In Figure 6, the graph on the right shows the results for Example 1, and the graph on the left shows the results for Comparative Example 1. In Figure 6, the vertical axis represents the processing efficiency.

[0081] The processing efficiency in Example 1 was 2212 nm / h, which showed sufficient processing efficiency. On the other hand, the processing efficiency was 347 nm / h in Comparative Example 1. That is, it was confirmed that the processing efficiency in Example 1 was about six times higher than that in Comparative Example 1.

[0082] [Example 2] As the processing method of the examples of the present invention, processing was carried out under the following conditions: First, as the processing method of Example 2 of the present invention, in addition to the processing conditions of Example 1, a vacuum ultraviolet light irradiation unit was provided on the polishing pad, and vacuum ultraviolet light (wavelength 172 nm) was irradiated onto the polishing pad during processing. Further, Comparative Example 1 was prepared in the same manner as in Example 1, except that no ozone gas was supplied by the ozone gas supply unit and no ultraviolet light was irradiated by the ultraviolet light irradiator. In addition, Comparative Example 2 was prepared in the same manner as in Example 1, except that no ozone gas was supplied by the ozone gas supply unit, no ultraviolet light was irradiated by the ultraviolet light irradiation unit, and furthermore, ultraviolet light (wavelength 200-450 nm) was irradiated onto the polishing pad during processing. In addition, Comparative Example 3 was prepared in the same manner as in Example 1, except that no ozone gas was supplied by the ozone gas supply unit, no ultraviolet light was irradiated by the ultraviolet light irradiation unit, and vacuum ultraviolet light (wavelength 172 nm) was irradiated onto the polishing pad during processing.

[0083] For the above-mentioned Example 2, the surface roughness of the synthetic quartz glass before and after processing was measured and evaluated using a non-contact shape measuring device. Furthermore, the processing efficiency was confirmed for Example 1, Example 2, Comparative Example 1, and Comparative Example 3.

[0084] FIG. 7(a) shows the surface roughness of a portion of the processed area in the synthetic quartz glass before processing in Example 2, and FIG. 7(b) shows the surface roughness of a portion of the processed area in the synthetic quartz glass after processing in Example 2.

[0085] As shown in Figures 7(a) and 7(b), the surface roughness of part of the processed region of the synthetic quartz glass was sufficiently improved by the processing of Example 2. In addition, in the results of Figure 7(a), the arithmetic mean roughness (Ra) value in the measurement range of the processed surface of the synthetic quartz glass before processing began was 3.168 nm. In the results of Figure 7(b), the arithmetic mean roughness (Ra) value in the measurement range of the processed surface of the synthetic quartz glass after processing of Example 2 was 0.383 nm.

[0086] Fig. 8 shows the results of the processing efficiency of Example 1, Example 2, Comparative Example 1, and Comparative Example 3. In Fig. 8, four graphs show, from left to right, the results of Comparative Example 1, Comparative Example 3, Example 1, and Example 2. In Fig. 8, the vertical axis represents the processing efficiency.

[0087] The processing efficiency in Example 1 was 2212 nm / h, and the processing efficiency in Example 2 was 2938 nm / h, which showed sufficient processing efficiency. On the other hand, the processing efficiency was 347 nm / h in Comparative Example 1 and 1181 nm / h in Comparative Example 3. That is, it was confirmed that the processing efficiency in Example 2 was about 8.5 times higher than that in Comparative Example 1.

[0088] In addition, in Example 2, the polishing slurry had a concentration of 0.1 wt%, but the processing efficiency of Example 2 was similar to that of Comparative Example 1, where the polishing slurry had a concentration of 3.0 wt%, and it became clear that the concentration of the polishing slurry can be made sufficiently small in Example 2.

[0089] The degree of hydrophilicity of the polishing pad surface was confirmed by measuring the contact angle (θ) using an automatic contact angle meter for the above Comparative Examples 1 to 3. For the shape of the droplet on the processed member surface, the contact angle (θ) was defined as the angle between a line corresponding to the processed member surface and a tangent to the outline curve of the droplet at the intersection with the processed member surface. Furthermore, for the above Comparative Examples 1 to 3, the relationship between the processing time and the surface roughness of the synthetic quartz glass after processing for each processing time was confirmed. Furthermore, for the above Comparative Example 3, the surface roughness of the synthetic quartz glass before and after processing was measured using a non-contact shape measuring device and evaluated. Furthermore, the processing efficiency of the above Comparative Examples 1 to 3 was confirmed.

[0090] In Figure 9, (a) shows the contact angle results for Comparative Example 1, (b) for Comparative Example 2, and (c) for Comparative Example 3. The numerical values ​​shown in each figure in Figure 9 are values ​​of the contact angle (θ). As is clear from Figures 9(a) to (c), the contact angle value was smaller for the polishing pad irradiated with vacuum ultraviolet light than for the untreated polishing pad and the polishing pad irradiated with ultraviolet light, confirming that the surface of the polishing pad was sufficiently hydrophilized.

[0091] Figure 10 shows a graph illustrating the relationship between processing time and the surface roughness of the synthetic quartz glass after processing for each processing time. In Figure 10, the vertical axis represents surface roughness and the horizontal axis represents processing time. Of the three graphs in Figure 10, the top graph shows the results for Comparative Example 1, the middle graph shows the results for Comparative Example 2, and the bottom graph shows the results for Comparative Example 3.

[0092] 10, Comparative Examples 1 and 2 showed similar changes, and it took 180 minutes from the start of processing for the surface roughness to reach a finishing value of Ra: 0.5 nm or less. On the other hand, in Comparative Example 3, the surface roughness reached a finishing value of Ra: 0.5 nm or less 60 minutes after the start of processing.

[0093] FIG. 11(a) shows the surface roughness of a portion of the processed area of ​​the synthetic quartz glass of Comparative Example 3 before processing began, and FIG. 11(b) shows the surface roughness of a portion of the processed area of ​​the synthetic quartz glass of Comparative Example 3 after processing.

[0094] As shown in Figures 11(a) and 11(b), the surface roughness of part of the processed region of the synthetic quartz glass was improved by the processing of Comparative Example 3. In addition, in the results of Figure 11(a), the arithmetic mean roughness (Ra) value in the measurement range of the processed surface of the synthetic quartz glass before processing began was 3.056 nm. In addition, in the results of Figure 11(b), the arithmetic mean roughness (Ra) value in the measurement range of the processed surface of the synthetic quartz glass after processing of Comparative Example 3 was 0.400 nm.

[0095] Fig. 12 shows the results of the processing efficiency of Comparative Examples 1 to 3. In Fig. 12, three graphs show, from left to right, the results of Comparative Example 1, Comparative Example 2, and Comparative Example 3. In Fig. 12, the vertical axis represents the processing efficiency.

[0096] The processing efficiency in Comparative Example 1 was 347 nm / h, the processing efficiency in Comparative Example 2 was 400 nm / h, and the processing efficiency in Comparative Example 3 was 1181 nm / h. [Explanation of symbols]

[0097] 1 Processing equipment 2 Polishing plate 3. Synthetic quartz glass 4. Sample holder 5 polishing pads 6. Slurry supply section 60 Polishing Slurry 7 Slurry supply bottle 70 Stirring bar 8 Ozone gas supply unit 9 Ultraviolet light irradiation section 10 Vacuum ultraviolet light irradiation section

Claims

1. The method comprises the steps of irradiating an abrasive slurry containing abrasive grains with ultraviolet light and supplying ozone gas to increase the amount of hydroxyl groups exposed on the surfaces of the abrasive grains, dropping the abrasive slurry onto a predetermined abrasive pad provided on a polishing table, and displacing the predetermined abrasive pad while in contact with a workpiece made of any one of synthetic quartz glass, soda-lime glass, borosilicate glass, alkali-free glass, high silica glass, fused quartz glass, other oxide-based glass containing silicon oxide as a main component, SiC, and silicon-based ceramics represented by Si 3 N 4 , and having silanol groups on the surface; By irradiating the predetermined polishing pad with vacuum ultraviolet light, the surface of the predetermined polishing pad is made hydrophilic, thereby improving the retention of the polishing slurry on the predetermined polishing pad. Processing method.

2. The abrasive grains are cerium oxide abrasive grains The processing method according to claim 1.

3. A polishing platen; a predetermined polishing pad provided on the polishing platen; a holding mechanism for holding a workpiece made of any one of synthetic quartz glass, soda-lime glass, borosilicate glass, alkali-free glass, high-silica glass, fused quartz glass, other oxide-based glass mainly composed of silicon oxide, and silicon-based ceramics typified by SiC and Si 3 N 4 and having silanol groups on the surface, in contact with the predetermined polishing pad; a slurry supply unit that drops a polishing slurry containing abrasive grains onto the predetermined polishing pad; an ultraviolet light irradiation unit that irradiates the polishing slurry with ultraviolet light; an ozone gas supply unit that supplies ozone gas to the polishing slurry; a driving unit that displaces the predetermined polishing pad while the predetermined polishing pad is in contact with the workpiece; a vacuum ultraviolet light irradiation unit that irradiates the predetermined polishing pad with vacuum ultraviolet light; The ultraviolet light irradiation unit irradiates the polishing slurry with the ultraviolet light, and the ozone gas supply unit supplies the ozone gas to the polishing slurry, thereby increasing the amount of hydroxyl groups exposed on the surfaces of the abrasive grains; By irradiating the predetermined polishing pad with the vacuum ultraviolet light, the surface of the predetermined polishing pad is made hydrophilic, thereby improving the retention of the polishing slurry on the predetermined polishing pad. Processing equipment.

4. The abrasive grains are cerium oxide abrasive grains. The processing device according to claim 3 .

Images