OMOG photomask manufacturing method

Abstract

The invention discloses an OMOG photomask manufacturing method. The method comprises the following steps: providing a transparent substrate; depositing a silicon layer or a molybdenum layer with a preset thickness on the transparent substrate; carrying out patterned molybdenum focused ion beam scanning on the silicon layer to enable Mo ions to move into the silicon layer in a scanned area so as to form a patterned molybdenum silicide layer; or carrying out patterned silicon focused ion beam scanning on the molybdenum layer to enable the Si ions to move into the molybdenum layer in the scanned area so as to form a patterned molybdenum silicide layer; and removing the unreacted silicon layer or molybdenum layer to form the OMOG photomask. The thickness of the molybdenum silicide layer can be reduced to the maximum extent, the light absorption rate can be improved to the maximum extent, the development requirement of the OMOG photomask can be met, and the manufacturing cost can be saved.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to an OMOG photomask manufacturing method. Background Technology

[0002] With advancements in photolithography technology, OMOG (opaque MoSi on glass) masks are widely used in the production of masks for critical photolithography layers to reduce the impact of mask 3D effects. OMOG uses MoSi as the absorption layer, and the molybdenum silicide layer provides sufficient optical density and has a high extinction coefficient (k). A very thin molybdenum silicide layer can effectively block light at a wavelength of 193 nm, reducing the mask 3D effects that plague ultra-large numerical aperture immersion lithography, thereby improving pattern fidelity and resolution.

[0003] Generally, thinner molybdenum silicide layers can reduce edge morphology effects, effectively avoiding distortion, uneven peak intensity, and uneven sidelobe width caused by edge morphology effects, thus achieving better resolution and contrast. In recent years, in order to enable molybdenum silicide layers to fully absorb ultraviolet light under thinner conditions, OMOG photomasks based on multilayer MoSi have been designed. The multilayer MoSi layers have different molybdenum and silicon contents to give each layer different optical parameters (n, k). The increased reflection light between the interfaces of the multilayer molybdenum silicide layers can improve the absorption rate, thereby enabling full absorption of ultraviolet light under thinner conditions.

[0004] However, existing technologies use sputtering deposition to form the molybdenum silicide layer of OMOG photomasks. The sputtered MoSi film has a fixed molybdenum and silicon content with uniform distribution. While a single-layer molybdenum silicide layer has a fixed content, multi-layer layers can only increase reflected light at the interlayer interfaces. The ability of multi-layer molybdenum silicide layers to increase reflected light is limited. Therefore, although multi-layer molybdenum silicide layers can increase reflected light and improve absorption to some extent, they cannot achieve the development goal of minimizing molybdenum silicide layer thickness and maximizing light absorption required for OMOG photomasks. Furthermore, the Mo and Si content of the MoSi target used in sputtering deposition is fixed, making it difficult to adjust the Mo and Si content in the sputtered MoSi film by changing process parameters. The only way to form MoSi films with different Mo and Si contents is to use different MoSi targets. Manufacturing OMOG photomasks requires multiple MoSi targets with different Mo and Si contents, resulting in high raw material costs and significantly impacting the manufacturing cost of OMOG photomasks.

[0005] Therefore, traditional OMOG photomask manufacturing processes have technical problems that cannot meet the development needs of OMOG photomasks and have high process costs, which affect the manufacturing cost of OMOG photomasks. Summary of the Invention

[0006] The purpose of this invention is to provide an OMOG photomask manufacturing method to solve the technical problems of traditional OMOG photomask manufacturing methods, which cannot meet the development needs of OMOG photomasks and have high process costs, thus affecting the manufacturing cost of OMOG photomasks.

[0007] To achieve the above objectives, the present invention provides an OMOG photomask manufacturing method, comprising the following steps: Provide transparent substrates; A silicon or molybdenum layer of predetermined thickness is deposited on a transparent substrate; A patterned molybdenum focused ion beam scan is performed on the silicon layer to move Mo ions into the silicon layer within the scanned region, forming a patterned molybdenum silicide layer. or, A patterned silicon focused ion beam scan is performed on the molybdenum layer to move Si ions into the molybdenum layer within the scanned region, forming a patterned molybdenum silicide layer. Unreacted silicon or molybdenum layers are removed to form an OMOG photomask.

[0008] The aforementioned OMOG photomask manufacturing method first deposits a silicon or molybdenum layer of a predetermined thickness on a transparent substrate, then performs patterned molybdenum focused ion beam scanning on the silicon layer, causing Mo ions to move into the scanned area of ​​the silicon layer to form a patterned molybdenum silicide layer; or, it performs patterned silicon focused ion beam scanning on the molybdenum layer, causing Si ions to move into the scanned area of ​​the molybdenum layer to form a patterned molybdenum silicide layer. This method can adjust the content of Mo and Si and the distribution gradient of Mo or Si atoms in the final patterned molybdenum silicide layer by controlling the energy, flux, and scanning speed of the molybdenum or silicon focused ion beam. The patterned molybdenum silicide layer can form a continuous molybdenum-silicon composition variation, and the gradient distribution of Mo or Si atoms in the patterned molybdenum silicide layer can form intralayer reflection and repeated absorption of ultraviolet light, thereby allowing the reflected light between the interfaces of multiple molybdenum silicide layers to be repeatedly absorbed by each layer, maximizing the light absorption rate. Furthermore, the aforementioned OMOG photomask manufacturing method moves Mo ions into the silicon layer or Si ions into the molybdenum layer. Calculations show that the thickness of the patterned molybdenum silicide layer added to the surface of the original silicon or molybdenum layer is only 1% of the original silicon or molybdenum layer thickness. The final thickness of the patterned molybdenum silicide layer is almost equal to the thickness of the original silicon or molybdenum layer. By controlling the thickness of the original silicon or molybdenum layer, the thickness of the patterned molybdenum silicide layer can be well controlled. Therefore, the aforementioned OMOG photomask manufacturing method can reduce the thickness of the patterned molybdenum silicide layer as much as possible while improving the light absorption rate, and can well achieve the development goal of minimizing the thickness of the molybdenum silicide layer and maximizing the light absorption rate required for OMOG photomasks.

[0009] Furthermore, the aforementioned OMOG photomask manufacturing method can form molybdenum silicide layers with arbitrary Mo and Si contents as needed. It only requires one elemental molybdenum target and one elemental silicon target to form multiple molybdenum silicide layers with different Mo and Si contents, eliminating the need for multiple MoSi targets with varying Mo and Si contents. This effectively reduces raw material costs and significantly saves on OMOG photomask manufacturing costs. Moreover, the method uses a molybdenum focused ion beam to pattern the silicon layer, or a silicon focused ion beam to pattern the molybdenum layer. After scanning, a patterned molybdenum silicide layer is directly formed. Once the patterned molybdenum silicide layer is formed, only the unreacted silicon or molybdenum layer needs to be removed to form the OMOG photomask, completing the OMOG photomask fabrication. This eliminates the need for patterning processes such as coating and exposure in traditional OMOG photomask manufacturing, simplifying the OMOG photomask fabrication process, effectively improving OMOG photomask production efficiency, and further saving manufacturing costs.

[0010] In summary, the above-mentioned OMOG photomask manufacturing method can minimize the thickness of the patterned molybdenum silicide layer and maximize the light absorption rate, achieving the development goal of minimizing the thickness of the patterned molybdenum silicide layer and maximizing the light absorption rate required for OMOG photomasks. Furthermore, the above-mentioned OMOG photomask manufacturing method can effectively reduce process costs and save on OMOG photomask manufacturing costs.

[0011] In one embodiment, the beam spot size of the molybdenum focused ion beam or the silicon focused ion beam is no greater than 100 nm.

[0012] In one embodiment, the focal point temperature of the molybdenum focused ion beam or the silicon focused ion beam is 400°C to 800°C.

[0013] In one embodiment, The energy of the molybdenum focused ion beam is 1eV-100eV, the flux is 0.1mA-100mA, and the scanning speed is 0.1mm / s-100mm / s; or, The silicon focused ion beam has an energy of 10eV-100eV, a flux of 0.1mA-100mA, and a scanning speed of 0.1mm / s-100mm / s.

[0014] In one embodiment, after the step of forming a patterned molybdenum silicide layer, the step further includes: performing a rapid thermal annealing treatment on the molybdenum silicide layer.

[0015] In one embodiment, the rapid thermal annealing process is performed at a temperature of 400°C to 800°C.

[0016] In one embodiment, the preset thickness is no greater than 40 nm.

[0017] In one embodiment, the step of depositing a silicon layer or a molybdenum layer having a predetermined thickness on a transparent substrate includes: A silicon or molybdenum layer of predetermined thickness is deposited on a transparent substrate using sputtering deposition or atomic layer deposition.

[0018] In one embodiment, after the step of forming a patterned molybdenum silicide layer, the step further includes: implanting optimized atoms into the patterned molybdenum silicide layer.

[0019] In one embodiment, the optimized atom is at least one of nitrogen, oxygen, or carbon. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating an embodiment of an OMOG photomask manufacturing method. Figures 2 to 6 A schematic diagram of the structure of an OMOG photomask manufactured using the OMOG photomask manufacturing method of the present invention, according to an embodiment; Figures 7 to 11 A schematic diagram of the structure of an OMOG photomask manufactured using the OMOG photomask manufacturing method of the present invention, according to another embodiment; Figure 12 This is a flowchart illustrating an embodiment of an OMOG photomask manufacturing method.

[0021] Explanation of reference numerals in the attached figures: 10-Transparent substrate, 20-Silicon layer, 30-Molybdenum layer, 40-Patterned molybdenum silicide layer, 50-Transparent area, 60-OMOG photomask, 70-Molybdenum focused ion beam, 80-Silicon focused ion beam. Detailed Implementation

[0022] 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 may be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the invention. It should be understood that the invention can be implemented in various 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. The same reference numerals denote the same elements throughout. It should be understood that when a layer is referred to as being formed on other layers, it may be formed directly on the other layers, or there may be intervening film layers. The terms “upper,” “lower,” “front,” “back,” etc., indicating orientation or positional relationship based on the orientation or positional relationship shown in the drawings, are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention, wherein “longitudinal” can be understood as a direction perpendicular to the substrate surface, and “lateral” can be understood as a direction parallel to the substrate surface. 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 term "comprising" is used to identify the presence of features, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups. When used herein, the term "and / or" includes any and all combinations of the associated listed items. The terms "identical," "equal," and "consistent" include the meaning of being completely equal and identical, and may also include the meaning of being approximately identical or approximately equal within permissible process tolerances. The terms "first," "second," etc., in the specification are used to distinguish between similar elements and are not necessarily used to describe a particular order or chronological sequence. It should be understood that these terms, as used herein, may be replaced where appropriate, for example, to enable the embodiments of the invention described herein to operate in a different order than that described or shown herein. Similarly, if the methods described herein comprise a series of steps, and the order of these steps presented herein is not necessarily the only possible order in which these steps can be performed, and some of the described steps may be omitted and / or some other steps not described herein may be added to the method. If a component in one figure is the same as a component in another figure, although these components are easily identifiable in all figures, this specification will not label all identical components in every figure for the sake of clarity of description.

[0023] The present invention will be described more clearly and completely by way of embodiments and in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the following embodiments.

[0024] Please also refer to the following: Figures 1 to 6 One embodiment of the method for manufacturing an OMOG photomask 60 includes the following steps: Step S11: Provide a transparent substrate 10.

[0025] Specifically, such as Figure 2 As shown, a transparent substrate 10 is first provided. The transparent substrate 10 includes one of a quartz substrate, a soda lime substrate, a borosilicate substrate, an aluminum silicate substrate, a silicon substrate, and a silicon carbide substrate. The radial dimension of the transparent substrate 10 is between 1 inch and 100 inches, and the thickness is between 0.1 mm and 200 mm. For example, in this embodiment, the transparent substrate 10 can be a quartz substrate, and its radial dimension can be 4 inches, 6 inches, 8 inches, 12 inches, etc.

[0026] Step S12: Deposit a silicon layer 20 with a preset thickness on the transparent substrate 10.

[0027] In one embodiment, the silicon layer 20 is deposited using a thin-film deposition process such as sputtering deposition or atomic layer deposition. Both sputtering deposition and atomic layer deposition offer highly controllable film thickness, allowing precise control over the thickness of the deposited silicon layer 20. In practical applications, a specific thin-film deposition process can be selected as needed. This embodiment does not impose a specific limitation; for ease of explanation, this embodiment uses sputtering deposition to deposit the silicon layer 20 as an example. Specifically, the sputtering deposition process preferably employs a low-temperature DC magnetron sputtering process. The sputtering deposition process uses an inert gas (helium and / or argon) to bombard a silicon target to deposit the material onto the transparent substrate 10 to form the silicon layer 20. The silicon target uses a single-element silicon target comprising amorphous silicon with a purity of at least 99.99%. Further, before the sputtering deposition process, the thickness of the silicon layer 20 is calculated based on the thickness of the patterned molybdenum silicide layer 40 to be formed. During the sputtering deposition process, the deposition time is controlled according to the calculated thickness of the silicon layer 20 to deposit a silicon layer 20 with a preset thickness (e.g., ...). Figure 3 (As shown).

[0028] Step S13: Patterned molybdenum focused ion beam 70 scans the silicon layer 20, causing Mo ions to move into the silicon layer in the scanned area, forming a patterned molybdenum silicide layer 40.

[0029] Specifically, such as Figure 4 , Figure 5As shown, during the patterning of the silicon layer 20 by the molybdenum focused ion beam 70, the energy of the molybdenum focused ion beam 70 enables Mo ions to rapidly move into the silicon layer 20 and react with silicon to form molybdenum silicide. In this embodiment, the content of Mo and Si in the final patterned molybdenum silicide layer 40 can be adjusted by controlling the energy, flow rate, and scanning speed of the molybdenum focused ion beam 70. During the process, the energy, flow rate, and scanning speed of the molybdenum focused ion beam 70 are set in advance according to the preset thickness of the silicon layer 20 and the target Mo and Si content in the patterned molybdenum silicide layer 40. After the scan is completed, a molybdenum silicide layer with the target Mo and Si content can be accurately formed. Furthermore, under the action of the energy of the molybdenum focused ion beam 70, Mo ions move from near to far into the silicon layer 20, so that Mo atoms are distributed in a gradient in the formed patterned molybdenum silicide layer 40, wherein the content of Mo atoms decreases from the upper surface to the lower surface of the silicon layer 20. Furthermore, calculations show that after Mo ions move into the silicon layer 20 to form a patterned molybdenum silicide layer 40, the thickness of the patterned molybdenum silicide layer 40 on the surface of the original silicon layer 20 is only 1% of the thickness of the original silicon layer 20. The final thickness of the patterned molybdenum silicide layer 40 is almost equal to the thickness of the original silicon layer 20. By controlling the thickness of the original silicon layer 20, the thickness of the patterned molybdenum silicide layer 40 can be well controlled.

[0030] In this embodiment, the patterned molybdenum silicide layer 40 formed by the OMOG photomask manufacturing method exhibits a gradient distribution of Mo atoms, which can generate intralayer reflection and repeated absorption of ultraviolet light, thereby improving the light absorption rate. By using this method to fabricate multiple patterned molybdenum silicide layers 40 with different Mo and Si contents, reflected light can be increased at the interlayer interfaces of the multiple patterned molybdenum silicide layers 40. Furthermore, the intralayer reflection and repeated absorption of ultraviolet light by each patterned molybdenum silicide layer 40 can be superimposed, allowing the reflected light between the interfaces of the multiple patterned molybdenum silicide layers 40 to be repeatedly absorbed by each layer, thereby maximizing the light absorption rate.

[0031] The OMOG photomask manufacturing method of this embodiment can control the thickness of the patterned molybdenum silicide layer 40 by controlling the thickness of the original silicon layer 20. By controlling the energy, flux, and scanning speed of the molybdenum focused ion beam 70, the content of Mo and Si and the Mo atom distribution gradient in the finally formed patterned molybdenum silicide layer 40 can be adjusted. The adjustment of the film thickness, Mo and Si content, and Mo atom distribution gradient of the patterned molybdenum silicide layer 40 is simple and convenient.

[0032] Step S14: Remove the unreacted silicon layer 20 to form an OMOG photomask 60.

[0033] Specifically, after scanning the silicon layer 20 to form a patterned molybdenum silicide layer 40, an etching process is performed to remove unreacted silicon layer 20, forming a light-transmitting region 50, thus completing the fabrication of the OMOG photomask (e.g., Figure 6 (As shown). In this embodiment, a wet etching process is preferably used to remove the unreacted silicon layer 20. More preferably, an acidic etching solution, such as SPM (H2SO4 / H2O2), is used. The principle and implementation of the specific wet etching process are the same as those of the existing conventional wet etching process, and will not be described in detail in this embodiment.

[0034] In one embodiment, in order to reduce edge morphology effects and effectively control the thickness of the finally formed patterned molybdenum silicide layer 40, the preset thickness of the silicon layer 20 is no greater than 40 nm.

[0035] In this embodiment, the OMOG photomask fabrication method uses a molybdenum focused ion beam 70 to perform a patterned direct-write scan on the silicon layer 20, directly forming a patterned molybdenum silicide layer 40 after scanning. To achieve optimal pattern control, the scanning area of ​​the molybdenum focused ion beam 70 needs to be adjusted according to the pattern size. To ensure that the scanning area of ​​the molybdenum focused ion beam 70 matches the image size and meets the patterning requirements, in one embodiment, the beam spot size of the molybdenum focused ion beam 70 is no greater than 100 nm.

[0036] In one embodiment, to facilitate the reaction between molybdenum ions and silicon layer 20 and to prevent material evaporation, the focusing temperature of the molybdenum focused ion beam 70 is set at 400°C to 800°C. At this temperature, Mo ions tend to migrate into silicon layer 20 and form molybdenum silicide. More preferably, to ensure complete reaction between molybdenum and silicon, the focusing temperature of the molybdenum focused ion beam is controlled at 500°C to 800°C.

[0037] In one embodiment, to ensure that the small-spot molybdenum focused ion beam 70 has sufficient energy to rapidly form the patterned molybdenum silicide layer 40, the focusing temperature of the molybdenum focused ion beam 70 is ensured to instantly reach 400°C. o C-800 o C. The energy of the molybdenum focused ion beam 70 is 1eV-100eV, the flux is 0.1mA-100mA, and the scanning speed is 0.1mm / s-100mm / s.

[0038] In one embodiment, after forming the patterned molybdenum silicide layer, the step further includes: performing a rapid thermal annealing treatment on the patterned molybdenum silicide layer 40. This embodiment ensures complete reaction between molybdenum and silicon by performing a rapid thermal annealing treatment on the patterned molybdenum silicide layer 40. Preferably, in one embodiment, the rapid thermal annealing temperature is 400°C to 800°C.

[0039] In one embodiment, after step S14, the following step may be included: implanting optimized atoms into the patterned molybdenum silicide layer 40. Preferably, the optimized atoms are at least one of nitrogen atoms, oxygen atoms, or carbon atoms. This embodiment, by implanting a small amount of at least one of nitrogen atoms, oxygen atoms, or carbon atoms into the patterned molybdenum silicide layer 40, can further enhance the light absorption of the patterned molybdenum silicide layer 40 and improve the adhesion between the patterned molybdenum silicide layer 40 and the transparent substrate 10.

[0040] The OMOG photomask manufacturing method of the above embodiment first deposits a silicon layer 20 on a transparent substrate 10, and then scans the silicon layer 20 with a patterned molybdenum focused ion beam 70 to form a patterned molybdenum silicide layer 40. This method is suitable for forming silicon-rich patterned molybdenum silicide layers 40, which helps to improve production efficiency. In another embodiment, a molybdenum layer can also be deposited on a transparent substrate first, and then the molybdenum layer can be scanned with a patterned silicon focused ion beam 80 to form a patterned molybdenum silicide layer. This method is suitable for forming silicon-rich patterned molybdenum silicide layers 40, which also helps to improve production efficiency. Please also refer to [reference needed]. Figures 7 to 12 Another embodiment of the method for manufacturing an OMOG photomask 60 includes the following steps: Step S21: Provide a transparent substrate 10.

[0041] Specifically, such as Figure 7 As shown, a transparent substrate 10 is first provided. The transparent substrate 10 includes one of a quartz substrate, a soda lime substrate, a borosilicate substrate, an aluminum silicate substrate, a silicon substrate, and a silicon carbide substrate. The radial dimension of the transparent substrate 10 is between 1 inch and 100 inches, and the thickness is between 0.1 mm and 200 mm. For example, in this embodiment, the transparent substrate 10 can be a quartz substrate, and its radial dimension can be 4 inches, 6 inches, 8 inches, 12 inches, etc.

[0042] Step S22: Deposit a molybdenum layer 30 with a preset thickness on the transparent substrate 10.

[0043] In one embodiment, the molybdenum layer 30 is deposited using a thin film deposition process such as sputtering deposition or atomic layer deposition. Both sputtering deposition and atomic layer deposition offer highly controllable film thickness, allowing precise control over the thickness of the deposited molybdenum layer 30. In practical applications, a specific thin film deposition process can be selected as needed. This embodiment does not impose a specific limitation; for ease of explanation, this embodiment uses sputtering deposition to deposit the molybdenum layer 30 as an example. Specifically, the sputtering deposition process preferably employs a low-temperature DC magnetron sputtering process. The sputtering deposition process uses an inert gas (helium and / or argon) to bombard a molybdenum target to deposit the material onto the transparent substrate 10, forming the molybdenum layer 30. The molybdenum target uses a single molybdenum target containing amorphous molybdenum with a purity of at least 99.99%. Further, before the sputtering deposition process, the thickness of the molybdenum layer 30 is calculated based on the thickness of the patterned molybdenum silicide layer 40 to be formed. During the sputtering deposition process, the deposition time is controlled according to the calculated thickness of the molybdenum layer 30, depositing a molybdenum layer 30 with a preset thickness (e.g., ...). Figure 8 (As shown).

[0044] Step S23: Patterned silicon focused ion beam 80 scans the molybdenum layer 30 to move Si ions into the molybdenum layer 30 in the scanned area, forming a patterned molybdenum silicide layer 40.

[0045] Specifically, such as Figure 9 , Figure 10 As shown, during the patterning scanning of the molybdenum layer 30 using a silicon focused ion beam 80, the energy of the silicon focused ion beam 80 enables Si ions to rapidly move into the molybdenum layer 30 and react with molybdenum to form molybdenum silicide. In this embodiment, the content of Mo and Si in the final patterned molybdenum silicide layer 40 can be adjusted by controlling the energy, flow rate, and scanning speed of the silicon focused ion beam 80. During implementation, the energy, flow rate, and scanning speed of the silicon focused ion beam 80 are set in advance according to the preset thickness of the molybdenum layer 30 and the target Mo and Si content in the patterned molybdenum silicide layer 40. After scanning, a molybdenum silicide layer with the target Mo and Si content can be accurately formed. Furthermore, under the action of the energy of the silicon focused ion beam 80, Si ions move from near to far into the molybdenum layer 30, resulting in a gradient distribution of Si atoms in the formed patterned molybdenum silicide layer 40. Specifically, the content of Si atoms decreases from the upper surface to the lower surface of the molybdenum layer 30. Furthermore, calculations show that after Si ions move into the molybdenum layer 30 to form a patterned molybdenum silicide layer 40, the thickness of the patterned molybdenum silicide layer 40 on the surface of the original molybdenum layer 30 is only 1% of the thickness of the original molybdenum layer 30. The final thickness of the patterned molybdenum silicide layer 40 is almost equal to the thickness of the original molybdenum layer 30. By controlling the thickness of the original molybdenum layer 30, the thickness of the patterned molybdenum silicide layer 40 can be well controlled.

[0046] In this embodiment, the patterned molybdenum silicide layer 40 formed by the OMOG photomask manufacturing method exhibits a gradient distribution of Si atoms, which can generate intralayer reflection and repeated absorption of ultraviolet light, thereby improving the light absorption rate. By using this method to fabricate multiple patterned molybdenum silicide layers 40 with different Mo and Si contents, reflected light can be increased at the interlayer interfaces of the multiple patterned molybdenum silicide layers 40. Furthermore, the intralayer reflection and repeated absorption of ultraviolet light by each patterned molybdenum silicide layer 40 can be superimposed, allowing the reflected light between the interfaces of the multiple patterned molybdenum silicide layers 40 to be repeatedly absorbed by each layer, thereby maximizing the light absorption rate.

[0047] The OMOG photomask manufacturing method of this embodiment can control the thickness of the patterned molybdenum silicide layer 40 by controlling the thickness of the original molybdenum layer 30. By controlling the energy, flux, and scanning speed of the silicon focused ion beam 80, the content of Mo and Si and the Si atom distribution gradient in the finally formed patterned molybdenum silicide layer 40 can be adjusted. The adjustment of the film thickness, Mo and Si content, and Si atom distribution gradient of the patterned molybdenum silicide layer 40 is simple and convenient.

[0048] Step S24: Remove the unreacted molybdenum layer 30 to form an OMOG photomask 60.

[0049] Specifically, after scanning the molybdenum layer 30 to form a patterned molybdenum silicide layer 40, an etching process is performed to remove the unreacted molybdenum layer 30, forming a light-transmitting region 50, thus completing the fabrication of the OMOG photomask (e.g., Figure 11 (As shown). In this embodiment, a wet etching process is preferably used to remove the unreacted molybdenum layer 30. More preferably, an acidic etching solution, such as SPM (H2SO4 / H2O2), is used. The principle and implementation of the specific wet etching process are the same as those of the existing conventional wet etching process, and will not be described in detail in this embodiment.

[0050] In one embodiment, in order to reduce edge morphology effects and effectively control the thickness of the finally formed patterned molybdenum silicide layer 40, the preset thickness of the molybdenum layer 30 is no greater than 40 nm.

[0051] In this embodiment, the OMOG photomask fabrication method uses a silicon focused ion beam 80 to perform a patterned direct-write scan of the molybdenum layer 30, directly forming a patterned molybdenum silicide layer 40 after scanning. To achieve optimal pattern control, the scanning area of ​​the silicon focused ion beam 80 needs to be adjusted according to the pattern size. To ensure that the scanning area of ​​the silicon focused ion beam 80 matches the image size and meets the patterning requirements, in one embodiment, the beam spot size of the silicon focused ion beam 80 is no greater than 100 nm.

[0052] In one embodiment, to facilitate the reaction between silicon ions and the molybdenum layer 30 and to prevent material evaporation, the focusing temperature of the silicon focused ion beam 80 is set to 400°C to 800°C. At this temperature, Si ions tend to migrate into the molybdenum layer 30 and form molybdenum silicide. More preferably, to ensure complete reaction between molybdenum and silicon, the focusing temperature of the silicon focused ion beam 80 is controlled at 500°C to 800°C.

[0053] In one embodiment, to ensure that the small-spot silicon focused ion beam 80 has sufficient energy to rapidly form the patterned molybdenum silicide layer 40, the focusing temperature of the silicon focused ion beam 80 is ensured to instantaneously reach 400°C. o C-800 o C. The energy of the silicon focused ion beam 80 is 10eV-100eV, the flux is 0.1mA-100mA, and the scanning speed is 0.1mm / s-100mm / s.

[0054] Furthermore, similar to the above embodiments, the OMOG photomask manufacturing method of this embodiment may further include a step of rapid thermal annealing of the patterned molybdenum silicide layer after step S24, and / or a step of implanting optimized atoms into the patterned molybdenum silicide layer 40. The specific rapid thermal annealing step and optimized ion implantation step are the same as those in the above embodiments, and will not be described in detail here.

[0055] The above-mentioned OMOG photomask manufacturing method first deposits a silicon layer 20 or a molybdenum layer 30 with a preset thickness on a transparent substrate, and then scans the silicon layer 20 with a patterned molybdenum focused ion beam 70 to move Mo ions into the silicon layer 20 in the scanned area to form a patterned molybdenum silicide layer 40; or, scans the molybdenum layer 30 with a patterned silicon focused ion beam 80 to move Si ions into the molybdenum layer 30 in the scanned area to form a patterned molybdenum silicide layer 40. This method can adjust the content of Mo and Si and the distribution gradient of Mo or Si atoms in the finally formed patterned molybdenum silicide layer 40 by controlling the energy, flow rate and scanning speed of the molybdenum focused ion beam 70 or the silicon focused ion beam 80. The patterned molybdenum silicide layer 40 can form a continuous molybdenum-silicon composition variation. The distribution of Mo or Si atoms in the patterned molybdenum silicide layer 40 is gradient, which can form repeated absorption of ultraviolet light by intralayer reflection. Thus, the reflected light between the interfaces of the multilayer molybdenum silicide layers can be repeatedly absorbed by each layer, which can maximize the light absorption rate. Furthermore, the aforementioned OMOG photomask manufacturing method moves Mo ions into the silicon layer 20 or Si ions into the molybdenum layer 30. Calculations show that the thickness of the patterned molybdenum silicide layer 40 added to the surface of the original silicon layer 20 or molybdenum layer 30 is only 1% of the original thickness of the original silicon layer 20 or molybdenum layer 30. The final thickness of the patterned molybdenum silicide layer 40 is almost equal to the thickness of the original silicon layer 20 or molybdenum layer 30. By controlling the thickness of the original silicon layer 20 or molybdenum layer 30, the thickness of the patterned molybdenum silicide layer 40 can be well controlled. Therefore, the aforementioned OMOG photomask manufacturing method can reduce the thickness of the patterned molybdenum silicide layer 40 as much as possible while improving the light absorption rate, and can well achieve the development goal of minimizing the thickness of the molybdenum silicide layer and maximizing the light absorption rate required for OMOG photomasks.

[0056] Furthermore, the aforementioned OMOG photomask manufacturing method can form molybdenum silicide layers with arbitrary Mo and Si contents as needed. It only requires one elemental molybdenum target and one elemental silicon target to form multiple molybdenum silicide layers with different Mo and Si contents, eliminating the need for multiple MoSi targets with varying Mo and Si contents. This effectively reduces raw material costs and significantly saves on OMOG photomask manufacturing costs. Moreover, the method uses a molybdenum focused ion beam 70 to pattern the silicon layer 20, or a silicon focused ion beam 80 to pattern the molybdenum layer 30. After scanning, a patterned molybdenum silicide layer 40 is directly formed. Once the patterned layer 40 is formed, only the unreacted silicon layer 20 or molybdenum layer 30 needs to be removed to form the OMOG photomask, completing the OMOG photomask fabrication. This eliminates the need for patterning processes such as coating and exposure in traditional OMOG photomask manufacturing, simplifying the process and effectively improving production efficiency, further reducing manufacturing costs.

[0057] The above-mentioned OMOG photomask manufacturing method can minimize the thickness of the patterned molybdenum silicide layer 40 and maximize the light absorption rate, achieving the development goal of minimizing the thickness of the patterned molybdenum silicide layer 40 and maximizing the light absorption rate required for OMOG photomasks. Furthermore, the above-mentioned OMOG photomask manufacturing method can effectively reduce process costs and save on OMOG photomask manufacturing costs.

[0058] 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 scope of the present invention.

Claims

1. A method for manufacturing an OMOG photomask, characterized in that, Includes the following steps: Provide transparent substrates; A silicon layer or a molybdenum layer of predetermined thickness is deposited on the transparent substrate; The silicon layer is patterned by a molybdenum focused ion beam scan, which causes Mo ions to move into the silicon layer within the scanned area, forming a patterned molybdenum silicide layer. or, The molybdenum layer is patterned by silicon focused ion beam scanning, which causes Si ions to move into the molybdenum layer within the scanned region, forming a patterned molybdenum silicide layer. Unreacted silicon or molybdenum layers are removed to form an OMOG photomask.

2. The OMOG photomask manufacturing method according to claim 1, characterized in that, The beam spot size of the molybdenum focused ion beam or the silicon focused ion beam is no greater than 100 nm.

3. The OMOG photomask manufacturing method according to claim 1, characterized in that, The focusing temperature of the molybdenum focused ion beam or the silicon focused ion beam is 400℃~800℃.

4. The OMOG photomask manufacturing method according to claim 1, characterized in that, The energy of the molybdenum focused ion beam is 1eV-100eV, the flux is 0.1mA-100mA, and the scanning speed is 0.1mm / s-100mm / s; or, The silicon focused ion beam has an energy of 10eV-100eV, a flow rate of 0.1mA-100mA, and a scanning speed of 0.1mm / s-100mm / s.

5. The OMOG photomask manufacturing method according to claim 4, characterized in that, Following the step of forming a patterned molybdenum silicide layer, the method further includes the following step: subjecting the molybdenum silicide layer to rapid thermal annealing.

6. The OMOG photomask manufacturing method according to claim 5, characterized in that, The rapid thermal annealing process is performed at a temperature of 400℃ to 800℃.

7. The OMOG photomask manufacturing method according to claim 1, characterized in that, The preset thickness is no greater than 40nm.

8. The OMOG photomask manufacturing method according to claim 1, characterized in that, The step of depositing a silicon layer or a molybdenum layer of a predetermined thickness on the transparent substrate includes: A silicon or molybdenum layer of predetermined thickness is deposited on the transparent substrate using sputtering deposition or atomic layer deposition.

9. The OMOG photomask manufacturing method according to claim 1, characterized in that, Following the step of forming a patterned molybdenum silicide layer, the method further includes the step of implanting optimized atoms into the patterned molybdenum silicide layer.

10. The OMOG photomask manufacturing method according to claim 9, characterized in that, The optimized atom is at least one of nitrogen, oxygen, or carbon.

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