Polishing apparatus for substrates, method and method of manufacturing photomask blanks

Abstract

The application provides a polishing device for a substrate, a method for polishing the substrate and a manufacturing method for a photomask base plate, the polishing device for the substrate comprising: an ion generator for emitting a plasma or an ion beam to a surface of a substrate; at least one coil arranged at a periphery of the substrate, the coil being used to generate a magnetic field parallel to the surface of the substrate, so that the plasma or the ion beam is deflected in a direction parallel to the substrate under the action of the magnetic field. The technical scheme of the application avoids damaging the surface of the substrate during polishing, thereby significantly improving the flatness of the surface of the substrate and improving the roughness of the surface of the substrate.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to a substrate polishing apparatus, a method, and a method for manufacturing a photomask substrate. Background Technology

[0002] Substrates used in advanced optical manufacturing, IT, and optoelectronic industries require ultra-smooth and ultra-precise polishing techniques. Currently employed polishing techniques include magneto-rheological finishing (MRF), ion beam polishing (IBF), and atmospheric pressure plasma chemical finishing (APPCF).

[0003] Among these methods, magnetorheological polishing utilizes a flexible "small grinding head" with viscoplastic behavior, formed by the rheological changes of a magnetorheological polishing slurry in a gradient magnetic field. This slurry moves rapidly relative to the substrate, subjecting the substrate surface to significant shear forces and removing material. However, magnetorheological polishing is a contact machining method, which can damage the substrate surface. Ion beam polishing uses a neutral ion beam to bombard the substrate surface, removing atoms or molecules from specific areas to achieve ultra-smooth polishing. While this is a non-contact machining method, the ion beam bombards the substrate surface perpendicularly, still causing surface damage. Atmospheric pressure plasma chemical processing is based on the principle of plasma etching. It uses plasma to excite active particles, which react chemically with substrate surface atoms to generate gaseous products, thus processing the material. However, this method also uses plasma and active particles emitted perpendicularly towards the substrate surface, which can also cause some damage.

[0004] Therefore, the substrate polishing technology needs to be improved to avoid damaging the substrate surface. Summary of the Invention

[0005] The purpose of this invention is to provide a substrate polishing apparatus, a method, and a method for manufacturing a photomask substrate, so as to avoid damaging the substrate surface during the polishing process, thereby significantly improving the flatness and roughness of the substrate surface.

[0006] To achieve the above objectives, the present invention provides a substrate polishing apparatus, comprising:

[0007] An ion generator is used to emit plasma or ion beams onto a substrate surface.

[0008] At least one coil is disposed on the periphery of the substrate, the coil being used to generate a magnetic field parallel to the surface of the substrate, such that the plasma or the ion beam is deflected in a direction parallel to the substrate under the influence of the magnetic field.

[0009] Optionally, the polishing apparatus for the substrate includes at least four coils, each coil being uniformly disposed around the periphery of the substrate to generate a rotating magnetic field parallel to the surface of the substrate.

[0010] Optionally, each of the coils sequentially switches the current applied along the direction surrounding the substrate.

[0011] Optionally, two coils arranged symmetrically with respect to the central axis of the substrate are simultaneously connected to current.

[0012] Optionally, when two coils arranged symmetrically with respect to the central axis of the substrate are simultaneously connected to current, the directions of the currents connected to the two coils are opposite.

[0013] Optionally, the ion generator includes an anode, a cathode, and a radio frequency power supply, wherein the radio frequency power supply is connected to the anode and the cathode, respectively.

[0014] Optionally, the ion generator further includes an inert gas source for supplying inert gas between the anode and the cathode to generate chemically inactive inert gas ions or a chemically inactive ion beam.

[0015] Optionally, when the ion generator is used to emit plasma onto the substrate surface, the ion generator further includes a reactive gas source for supplying reactive gas between the anode and the cathode to generate chemically active reactive gas ions.

[0016] Optionally, the substrate polishing apparatus further includes:

[0017] The reaction chamber has a coil disposed around its periphery and an ion generator connected to it.

[0018] Optionally, the gas pressure in the reaction chamber is greater than 100 mTorr.

[0019] The present invention also provides a method for polishing a substrate, comprising:

[0020] Provide a substrate;

[0021] The substrate surface is polished using a deflected plasma or ion beam generated by the substrate polishing device.

[0022] The present invention also provides a method for manufacturing a photomask substrate, comprising:

[0023] A substrate is provided, and the surface of the substrate is polished using the substrate polishing method described above;

[0024] A phase-shifted layer is formed on the polished substrate;

[0025] A light-shielding layer is formed on the phase-shift layer;

[0026] A photoresist layer is formed on the light-shielding layer.

[0027] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0028] 1. The substrate polishing apparatus of the present invention provides at least one coil disposed around the periphery of the substrate. The coil is used to generate a magnetic field parallel to the surface of the substrate, causing plasma or ion beam emitted by an ion generator toward the surface of the substrate to be deflected in a direction parallel to the substrate under the action of the magnetic field. This avoids damage to the substrate surface during the polishing process, thereby significantly improving the flatness and roughness of the substrate surface.

[0029] 2. The substrate polishing method of the present invention uses a deflected plasma or ion beam generated by the substrate polishing device to polish the substrate surface, thereby avoiding damage to the substrate surface during the polishing process, thus significantly improving the flatness and roughness of the substrate surface.

[0030] 3. The method for manufacturing the photomask substrate of the present invention, by using the substrate polishing method to polish the substrate surface, significantly improves the flatness of the substrate surface and improves the roughness of the substrate surface, thereby improving the quality of the photomask substrate. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a substrate polishing apparatus according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of a substrate polishing apparatus according to another embodiment of the present invention;

[0033] Figure 3a This is a schematic diagram of plasma deflection according to an embodiment of the present invention;

[0034] Figure 3b This is a schematic diagram of the deflection direction of plasma and the direction of magnetic field according to an embodiment of the present invention;

[0035] Figure 4a This is a schematic diagram of the substrate before polishing;

[0036] Figure 4b This is a schematic diagram of a substrate polished using undeflected plasma or ion beam.

[0037] Figure 4c This is a schematic diagram of a substrate polished using deflected plasma or ion beam.

[0038] Figure 4d This is a schematic diagram of a substrate etched using plasma etching technology;

[0039] Figure 5 This is a flowchart of a substrate polishing method according to an embodiment of the present invention.

[0040] Among them, the appendix Figures 1-5 The annotations in the attached figures are explained as follows:

[0041] 11-Substrate; 111-Atoms; 12-Ion generator; 121-Anode; 122-Cathode; 123-RF power supply; 13-Coil; 14-Plasma; 15-Magnetic field; 16-Patterned photoresist layer. Detailed Implementation

[0042] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with the invention. It should be understood that the invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0043] It should be understood that when an element or layer is referred to as "on" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, parts, and / or processes, these elements, components, areas, layers, parts, and / or processes should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, part, and / or process from another element, component, area, layer, part, and / or process. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, part, and / or process discussed below may be referred to as a second element, component, area, layer, part, and / or process.

[0044] Spatial relation terms such as “below,” “under,” “below,” “below,” “above,” “on the top,” “on the bottom,” “front,” “back,” etc., are used herein for convenience of description to describe the relationship of one element or feature shown in the figure to other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below other elements,” “under them,” “on the bottom,” or “on its back” will be oriented “above,” “top,” or “right” of the other elements or features. Therefore, the exemplary terms “below,” “under,” and “on its back” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0045] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0046] An embodiment of the present invention provides a substrate polishing apparatus, the substrate polishing apparatus comprising: an ion generator for emitting plasma or an ion beam toward the substrate surface; and at least one coil disposed around the substrate, the coil being used to generate a magnetic field parallel to the substrate surface, such that the plasma or the ion beam is deflected in a direction parallel to the substrate under the action of the magnetic field.

[0047] See below. Figures 1 to 3b , Figures 4a to 4d The substrate polishing apparatus provided in this embodiment will be described in more detail.

[0048] The ion generator 12 is used to emit plasma or ion beams onto the surface of the substrate 11, and the plasma or ion beams emitted by the ion generator 12 are perpendicular to the surface of the substrate 11.

[0049] The substrate 11 is fixed to a chuck (not shown), and the ion generator 12 is disposed on the side of the substrate 11 away from the chuck. The surface of the substrate 11 can be either the front or back side, with the side of the substrate 11 to be polished facing the ion generator 12.

[0050] The cross-sectional shape of the substrate 11 can be circular or square, etc.

[0051] In one embodiment, such as Figure 1 and Figure 2 As shown, the ion generator 12 may include an anode 121, a cathode 122, and a radio frequency power supply 123, wherein the radio frequency power supply 123 is connected to both the anode 121 and the cathode 122. Figure 1 The diagram shown is a schematic of the ion generator 12 emitting plasma onto the surface of the substrate 11. Figure 1 The image shows plasma chemical polishing of the surface of the substrate 11; Figure 2 The diagram shown is a schematic of the ion generator 12 emitting an ion beam onto the surface of the substrate 11. Figure 2 The image shows ion beam polishing of the surface of the substrate 11.

[0052] It should be noted that, Figure 2 The anode 121, cathode 122, and radio frequency power supply 123 in the ion generator 12 are not shown; furthermore, the ion generator 12 is not limited to... Figure 1 and Figure 2 The components shown, such as the chuck, can serve as the cathode in the ion generator 12. Therefore, various ion generators commonly used in the art can be employed, as long as they are capable of emitting plasma or ion beams.

[0053] When the ion generator 12 emits plasma onto the surface of the substrate 11, the ion generator 12 also includes an inert gas source (not shown) and a reactive gas source (not shown). The inert gas source is used to supply inert gas between the anode 121 and the cathode 122, and the reactive gas source is used to supply reactive gas between the anode 121 and the cathode 122.

[0054] When the ion generator 12 emits an ion beam toward the surface of the substrate 11, the ion generator 12 also includes an inert gas source (not shown), which is used to supply inert gas between the anode 121 and the cathode 122. The ion generator 12 does not need to be equipped with a reaction gas source.

[0055] The inert gas may include at least one of helium, argon and nitrogen, and the reactant gas may include fluorine-containing gas (e.g. SF6, CF4) and / or chlorine-containing gas (e.g. Cl2, BCl3).

[0056] At least one coil 13 is disposed on the periphery of the substrate 11. The coil 13 is used to generate a magnetic field parallel to the surface of the substrate 11, and the area covered by the magnetic field is close to the surface of the substrate 11, so that the plasma or the ion beam perpendicular to the surface of the substrate 11 generates a deflection component in a direction parallel to the surface of the substrate 11 under the action of the magnetic field, and the direction of the deflection component is perpendicular to the direction of the magnetic field.

[0057] It should be noted that the winding method of the coil 13 is not limited, as long as the generated magnetic field is parallel to the surface of the substrate 11. Under the influence of the magnetic field, the charged ions in the plasma and the ion beam will experience force components perpendicular to the direction of the magnetic field and the direction of ion movement.

[0058] Furthermore, it should be noted that the substrate polishing apparatus also includes a power supply connected to the coil 13 to generate a magnetic field after current is supplied to the coil 13.

[0059] The substrate polishing apparatus further includes a reaction chamber (not shown), the coil 13 is disposed around the reaction chamber, the anode 121 and cathode 122 of the ion generator 12 are disposed in the reaction chamber, the radio frequency power supply 123, the inert gas source and the reaction gas source of the ion generator 12 are disposed around the reaction chamber, and the inert gas source and the reaction gas source are both connected to the reaction chamber.

[0060] The reaction chamber can be controlled to a vacuum or atmospheric pressure environment. Preferably, the gas pressure in the reaction chamber is greater than 100 mTorr.

[0061] Taking the emission of plasma from the ion generator 12 to the surface of the substrate 11 as an example, such as Figure 3a and Figure 3b As shown, Figure 3a Main view, Figure 3b This is a top view; the process by which the plasma is deflected in a direction parallel to the surface of the substrate 11 under the influence of the magnetic field includes: before the plasma 14 emitted by the ion generator 12 enters the region where the magnetic field 15 is located, i.e., before... Figure 3a In region N1, as shown, the plasma 14 is perpendicular to the surface of the substrate 11; after the plasma 14 enters the region where the magnetic field 15 is located, that is, in Figure 3aIn region N2, as shown, the plasma 14, under the influence of the magnetic field 15, generates a deflection force in a direction parallel to the surface of the substrate 11. The direction of this deflection force is perpendicular to the direction of the magnetic field, causing the deflected plasma to be perpendicular to the direction of the magnetic field. Consequently, when the direction of the magnetic field changes, the direction of plasma deflection also changes accordingly. Figure 3a and Figure 3b As shown, under the action of the magnetic field 15 in the X-axis direction, a deflection component force in the Y-axis direction is generated, causing the movement direction of the plasma 14 to be deflected from the Z-axis direction to the Y-axis direction. The X-axis and Y-axis directions are perpendicular to each other and parallel to the surface of the substrate 11, while the Z-axis direction is perpendicular to the surface of the substrate 11. It should be noted that the process by which the ion beam is deflected in a direction parallel to the surface of the substrate 11 under the action of the magnetic field is the same as the process described above.

[0062] when Figure 1 When the polishing apparatus for the substrate shown does not include the coil 13, the principle of plasma-chemical polishing of the substrate 11 surface can be as follows: The inert gas and the reactive gas are supplied between the anode 121 and the cathode 122. The inert gas is excited by the radio frequency power supply 123 into a uniform and stable, chemically inactive plasma. The reactive gas, under the excitation of the plasma, generates chemically active reactive gas ions. Both the chemically inactive inert gas ions and the chemically active reactive gas ions are incident on the substrate 11 surface in a direction perpendicular to the substrate 11 surface. The chemically inactive inert gas ions provide a physical method to polish the substrate 11 surface, while the chemically active reactive gas ions react chemically with the atoms of matter on the substrate 11 surface to generate gaseous products that remove foreign matter from the substrate 11 surface and polish the substrate 11 surface. The inert gas ions and reactive gas ions can be mixed in an optimized ratio to simultaneously remove foreign matter from the substrate 11 and polish it.

[0063] when Figure 2 When the polishing apparatus for the substrate shown does not include the coil 13, the principle of ion beam polishing of the substrate 11 surface can be as follows: the inert gas is supplied between the anode and the cathode in the ion generator 12, the radio frequency power supply in the ion generator 12 is turned on to supply current to the anode and the cathode, and the cathode current is heated by high-frequency electromagnetic oscillation or discharge, so that the inert gas is ionized into a chemically inactive ion beam. Under the action of the electric field, the ion beam is accelerated towards the surface of the substrate 11, so that the chemically inactive ion beam is incident on the surface of the substrate 11 in a direction perpendicular to the surface of the substrate 11, so as to sputter away the atoms on the surface of the substrate 11 one by one, thereby achieving polishing of the surface of the substrate 11.

[0064] It should be noted that plasma chemical polishing of the substrate 11 involves emitting plasma over a large area of ​​the substrate 11 surface; while ion beam polishing of the substrate 11 involves emitting an ion beam over a small area of ​​the substrate 11 surface.

[0065] When the polishing apparatus for the substrate includes the coil 13, Figure 1 The plasma (containing chemically inert gas ions and chemically active reactive gas ions) in the illustrated embodiments and Figure 2 In the illustrated embodiment, the chemically inactive ion beams are all deflected parallel to the surface of the substrate 11 under the influence of the magnetic field. This causes most of the plasma and ion beam movement to be deflected parallel to the surface of the substrate 11, effectively deflecting the force perpendicular to the substrate 11 surface. This deflection polishes the substrate 11 surface, reducing the perpendicular impacts of the plasma and ion beam on the atoms of the substrate 11 surface, thus minimizing impact damage. Furthermore, the force parallel to the substrate 11 surface is primarily used to remove protrusions (where more atoms are stacked) from the substrate 11 surface, reducing material removal from flat areas and further minimizing damage. Therefore, under the influence of a magnetic field parallel to the substrate 11 surface, the substrate 11 surface can be polished to the atomic scale, significantly improving its flatness and roughness.

[0066] Furthermore, the movement direction of the plasma and the ion beam is deflected to be parallel to the surface of the substrate 11, which enables the plasma and the ion beam to diffuse on the surface of the substrate 11, thereby improving the uniformity of polishing the surface of the substrate 11 and increasing the polishing speed.

[0067] Furthermore, it should be noted that, apart from most of the plasma and ion beams being deflected parallel to the surface of the substrate 11, a small portion of the plasma and ion beams still move perpendicular to the surface of the substrate 11 and at acute or obtuse angles to the surface of the substrate 11.

[0068] Among them, see Figures 4a to 4d , Figure 4a This is a schematic diagram of the surface of the substrate 11 before polishing. Figure 4b This is a schematic diagram of the surface of substrate 11 after polishing with undeflected (i.e., perpendicular to the surface of substrate 11) plasma or ion beam. Figure 4c This is a schematic diagram of the surface of substrate 11 after polishing with deflected plasma or ion beam. Figure 4dThis is a schematic diagram of the surface of substrate 11 after being etched using a plasma etching process. Figures 4a to 4d The diagram illustrates the atoms 111 on the surface of substrate 11 to illustrate the flatness of the substrate 11 surface; from Figure 4a As can be seen, before polishing, position A1 on the surface of the substrate 11 has more similar substrate atoms 111 compared to other positions, that is, position A1 on the surface of the substrate 11 has a protrusion compared to other positions; from Figure 4b As can be seen, after polishing, although the protruding atoms 111 at position A1 on the surface of the substrate 11 are removed, the atoms 111 at positions A2 and A3 are also removed. This indicates that the undeflected plasma or ion beam not only polished the protruding positions but also the flat positions outside the protruding positions, that is, it also impacted and removed the atoms 111 on the flat positions of the substrate 11 surface, thus causing damage to the surface of the substrate 11. Figure 4c As can be seen, after polishing, only the protruding atoms 111 at position A1 on the surface of the substrate 11 were removed, while atoms 111 at other flat positions were not removed. This indicates that the plasma or ion beam deflected parallel to the surface of the substrate 11 only polished the protruding positions, not the other flat positions, thus reducing damage to the surface of the substrate 11 and resulting in a smooth and rough surface after polishing. Figure 4d As can be seen, the plasma etching process uses chemically active ions to etch and remove the entire surface of the substrate 11 exposed by the patterned photoresist layer 16, using the patterned photoresist layer 16 as a mask. That is, the ion etching removes part of the thickness of the substrate 11, and the atoms 111 at position A4 on the surface of the substrate 11 after etching are removed, indicating that it will also cause damage to the surface of the substrate 11.

[0069] Furthermore, the plasma etching process is used to remove a portion of the substrate 11's thickness. It directly bombards the surface of the substrate 11 with plasma generated by ionizing fluorine-containing and / or chlorine-containing gases, resulting in higher energy and activity of the ions. Additionally, the plasma etching process uses a high DC bias in the reaction chamber, causing the plasma to accelerate towards the substrate 11 surface in a direction perpendicular to the substrate 11, thus generating a greater impact force. Moreover, the low gas pressure (e.g., less than 10 mTorr) in the reaction chamber also contributes to the high energy of the plasma. Therefore, the plasma etching process achieves a high material removal rate and fast removal speed from the substrate 11 surface, but also causes more damage to the substrate 11 surface (e.g., vacancies, dislocations, etc.).

[0070] and Figure 4cThe plasma and ion beam polishing used in this process is atomic-scale polishing, used to improve the surface roughness of the substrate 11. Furthermore, the plasma and ion beam polishing process employs low-energy, inactive or low-activity ions. The reaction chamber in the substrate polishing apparatus does not use a DC bias voltage, thus avoiding acceleration of the plasma and ion beam and reducing impact on the substrate 11 surface. The gas pressure in the reaction chamber of the substrate polishing apparatus is relatively high (e.g., greater than 100 mTorr), which allows the ions to have lower energy, thereby controlling damage to the substrate 11 surface. Therefore, compared to plasma etching, plasma and ion beam polishing has a lower material removal rate and slower removal speed on the substrate 11 surface, while causing very little damage.

[0071] Furthermore, the larger the current and the greater the number of coils 13, the stronger the magnetic field generated, which makes it easier for the plasma or the ion beam to deflect in a direction parallel to the surface of the substrate 11.

[0072] Preferably, the substrate polishing apparatus includes at least four coils 13, and each coil 13 is uniformly disposed around the periphery of the substrate 11, that is, each coil 13 is symmetrically arranged with respect to the central axis of the substrate 11, for generating a rotating magnetic field parallel to the surface of the substrate 11. Under the action of the rotating magnetic field, the magnetic field can be more uniformly distributed in various regions near the surface of the substrate 11, so that the plasma or the ion beam generates deflection components in various directions parallel to the surface of the substrate 11, thereby making the plasma or the ion beam, after being deflected under the action of the rotating magnetic field, more uniformly distributed in various regions parallel to the surface of the substrate 11, thereby improving the polishing uniformity of various regions of the substrate 11 surface, and further improving the flatness of the polished substrate 11 surface.

[0073] More preferably, the number of coils 13 is a positive integer multiple of 4, and each coil 13 is evenly disposed on the periphery of the substrate 11, so that the magnetic field is more evenly distributed in various regions near the surface of the substrate 11.

[0074] When the rotating magnetic field is generated, each of the coils 13 sequentially and cyclically switches the current along the direction surrounding the substrate 11, that is, each of the coils 13 sequentially and continuously switches the current along the same direction surrounding the substrate 11, and only one coil 13 switches the current at any given time; or, each of the coils 13 sequentially and cyclically switches the current along the direction surrounding the substrate 11, and two coils 13 symmetrically arranged with respect to the central axis of the substrate 11 switch the current simultaneously, that is, each of the coils 13 sequentially and continuously switches the current along the same direction surrounding the substrate 11, and two coils 13 switch the current at any given time.

[0075] Furthermore, when two coils 13 symmetrically arranged with respect to the central axis of the substrate 11 are simultaneously connected to current, the current directions of the two symmetrically arranged coils 13 are opposite, so that the magnetic field directions generated by the two symmetrically arranged coils 13 are the same, thereby increasing the magnetic field strength and making the surface of the substrate 11 more uniformly polished.

[0076] Taking four coils 13 (e.g., a first coil, a second coil, a third coil, and a fourth coil) as an example, the generation of the rotating magnetic field is explained as follows: The first coil, the second coil, the third coil, and the fourth coil are arranged sequentially and evenly around the periphery of the substrate 11 in a clockwise direction. The first coil and the third coil are symmetrical with respect to the central axis of the substrate 11, and the second coil and the fourth coil are also symmetrical with respect to the central axis of the substrate 11. Current can be sequentially applied to the first coil, the second coil, the third coil, and the fourth coil, with only one coil applied at a time. That is, the first coil, the second coil, the third coil, and the fourth coil are sequentially and continuously switched with current, so that the rotating magnetic field is generated in the region near the surface of the substrate 11. Alternatively, the first coil and the third coil can be applied with current in opposite directions (at which time the second coil and the fourth coil are not applied with current), and then the second coil and the fourth coil can be applied with current in opposite directions (at which time the first coil and the third coil are not applied with current), and so on, so that the rotating magnetic field is generated in the region near the surface of the substrate 11.

[0077] In other embodiments, when the number of coils 13 is less than or equal to three, or when the number of coils 13 is at least four and each coil 13 fails to sequentially switch the current, the magnetic field generated by each coil 13 is not a rotating magnetic field. In this case, the size, current intensity, and number of coils 13 can be increased so that the magnetic field generated by the coils 13 can cover the entire surface of the substrate 11, thereby improving the uniformity of the surface polishing of the substrate 11. Furthermore, if two coils 13 symmetrically arranged with respect to the central axis of the substrate 11 are simultaneously connected to current, by having the current directions of the two symmetrically arranged coils 13 connected in opposite directions, the magnetic field directions generated by the two symmetrically arranged coils 13 are also the same, thereby increasing the magnetic field intensity and making the surface polishing of the substrate 11 faster and more uniform.

[0078] It should be noted that the substrate polishing apparatus is not limited to the components described above, but may also include other necessary components, such as a vacuum pumping device for extracting gas from the reaction chamber to adjust the gas pressure in the reaction chamber, and for extracting gaseous products generated by the reaction.

[0079] As can be seen from the above, the substrate polishing apparatus provided by the present invention, by setting at least one coil around the substrate, the coil is used to generate a magnetic field parallel to the substrate surface, so that the plasma or ion beam emitted by the ion generator toward the substrate surface is deflected in a direction parallel to the substrate under the action of the magnetic field, thereby avoiding damage to the substrate surface during the polishing process, thus significantly improving the flatness of the substrate surface and improving the roughness of the substrate surface.

[0080] One embodiment of the present invention provides a method for polishing a substrate, see reference. Figure 5 ,from Figure 5 As can be seen from the image, the polishing method for the substrate includes:

[0081] Step S1, provide a substrate;

[0082] Step S2: Polish the surface of the substrate using a deflected plasma or ion beam generated by the substrate polishing device.

[0083] The substrate polishing method provided in this embodiment will be described in detail below.

[0084] According to step S1, a substrate is provided.

[0085] The substrate material may include at least one of quartz, borosilicate, aluminum silicate, silicon, and silicon carbide.

[0086] According to step S2, the substrate surface is polished using a deflected plasma or ion beam generated by the substrate polishing device.

[0087] The polishing apparatus for the substrate is described above and will not be repeated here.

[0088] By adjusting parameters such as the strength of the magnetic field in the polishing device of the substrate, the rotation frequency of the rotating magnetic field, and the gas pressure in the reaction chamber, minimal damage to the surface of the substrate 11 can be achieved during polishing.

[0089] Because the substrate surface is polished by the deflected plasma or ion beam generated by the polishing device of the substrate, damage to the substrate surface is avoided during the polishing process, thereby significantly improving the flatness and roughness of the substrate surface.

[0090] An embodiment of the present invention provides a method for manufacturing a photomask substrate, the method comprising:

[0091] First, a substrate is provided, and the surface of the substrate is polished using the aforementioned substrate polishing method. The substrate polishing method is described above and will not be repeated here.

[0092] Then, a phase-shifted layer is formed on the polished substrate.

[0093] The phase shift layer can be formed on the polished substrate using a sputtering deposition process.

[0094] The material of the phase shift layer may include MoSi. x O y N z .

[0095] Then, a light-shielding layer is formed on the phase-shifted layer.

[0096] The light-shielding layer can be formed on the phase-shifted layer using a sputtering deposition process.

[0097] The material of the light-shielding layer may include at least one of Cr, CrO2, CrN, etc.

[0098] Then, a photoresist layer is formed on the light-shielding layer.

[0099] The photoresist layer can be formed on the light-shielding layer by spin coating.

[0100] By using the aforementioned polishing method to polish the substrate surface, the flatness of the substrate surface is significantly improved, the roughness of the substrate surface is reduced, and thus the quality of the photomask substrate is enhanced.

[0101] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A substrate polishing apparatus, characterized in that, include: An ion generator is used to emit plasma or ion beams onto a substrate surface. At least one coil is disposed on the periphery of the substrate. The coil is used to generate a magnetic field parallel to the surface of the substrate, so that the plasma or the ion beam is deflected in a direction parallel to the substrate under the action of the magnetic field. The direction of the deflected plasma or the ion beam is perpendicular to the direction of the magnetic field.

2. The substrate polishing apparatus as described in claim 1, characterized in that, The polishing apparatus for the substrate includes at least four coils, each coil being uniformly disposed around the periphery of the substrate to generate a rotating magnetic field parallel to the surface of the substrate.

3. The substrate polishing apparatus as described in claim 2, characterized in that, Each of the coils sequentially switches the current along the direction surrounding the substrate.

4. The substrate polishing apparatus as described in claim 3, characterized in that, Two coils, symmetrically arranged with respect to the central axis of the substrate, are simultaneously connected to current.

5. The substrate polishing apparatus as described in claim 4, characterized in that, When two coils, which are symmetrically arranged with respect to the central axis of the substrate, are simultaneously connected to current, the directions of the currents connected to the two coils are opposite.

6. The substrate polishing apparatus as claimed in claim 1, characterized in that, The ion generator includes an anode, a cathode, and a radio frequency power supply, wherein the radio frequency power supply is connected to the anode and the cathode, respectively.

7. The substrate polishing apparatus as claimed in claim 6, characterized in that, The ion generator also includes an inert gas source, which is used to supply inert gas between the anode and the cathode to generate chemically inactive inert gas ions or chemically inactive ion beams.

8. The substrate polishing apparatus as claimed in claim 7, characterized in that, When the ion generator is used to emit plasma onto the substrate surface, the ion generator further includes a reactive gas source for supplying reactive gas between the anode and the cathode to generate chemically active reactive gas ions.

9. The substrate polishing apparatus as claimed in claim 1, characterized in that, The substrate polishing apparatus further includes: The reaction chamber has a coil disposed around its periphery and an ion generator connected to it.

10. The substrate polishing apparatus as claimed in claim 9, characterized in that, The gas pressure in the reaction chamber is greater than 100 mTorr.

11. A method for polishing a substrate, characterized in that, include: Provide a substrate; The substrate surface is polished using a deflected plasma or ion beam generated by a substrate polishing apparatus as described in any one of claims 1 to 10.

12. A method for manufacturing a photomask substrate, characterized in that, include: A substrate is provided, and the surface of the substrate is polished using the substrate polishing method as described in claim 11; A phase-shifted layer is formed on the polished substrate; A light-shielding layer is formed on the phase-shift layer; A photoresist layer is formed on the light-shielding layer.

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