EUV mask plate and manufacturing method thereof
By directly forming a patterned absorption layer in EUV mask manufacturing using molybdenum/silicon focused ion beam scanning technology, the problem of low production efficiency has been solved, enabling efficient and low-cost EUV mask manufacturing and ensuring product performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-04-10
AI Technical Summary
The low production efficiency of EUV mask templates affects manufacturing costs.
The molybdenum/silicon focused ion beam scanning technology is used to directly form patterned absorption layers on transparent substrates, simplifying the manufacturing process. This includes patterning of multilayer reflective films and protective layers, avoiding the traditional absorption layer deposition and coating steps.
This improves the production efficiency of EUV masks, reduces manufacturing costs, and ensures the light absorption rate and pattern fidelity of the absorption layer, thus ensuring stable and reliable product performance.
Smart Images
Figure CN121843498A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of integrated circuit manufacturing technology, and in particular to an EUV mask and its manufacturing method. Background Technology
[0002] With the continuous development of semiconductor technology and the shrinking size of semiconductor devices, traditional visible light or ultraviolet light can no longer meet the requirements for pattern resolution, and advanced semiconductor manufacturing processes have entered the EUV era. Reflective EUV masks are key components in extreme ultraviolet (EUV) lithography technology. Designed to address the characteristic that short wavelengths such as 13.5nm are easily absorbed, they replace traditional transmissive masks to achieve high-resolution chip manufacturing and are widely used in the field of advanced semiconductor manufacturing processes.
[0003] EUV photomasks consist of an ultra-low expansion quartz glass substrate, a periodic molybdenum-silicon multilayer reflective film, and an absorption layer. The multilayer reflective film reflects EUV light through 40-50 pairs of alternating silicon-molybdenum layers. A protective layer covers the surface to reduce the defect rate. The absorption layer selectively blocks reflected light to form micro / nano circuit patterns. EUV photomasks are among the most precise devices in semiconductor manufacturing. Their manufacturing process is extremely complex, requiring multiple steps such as multilayer molybdenum-silicon film deposition, protective film deposition, absorption layer deposition, and absorption layer patterning. This results in low production efficiency for EUV photomasks, impacting their manufacturing cost.
[0004] Therefore, there is a need to provide an EUV mask manufacturing method that is highly efficient and helps to save on EUV mask manufacturing costs. Summary of the Invention
[0005] The purpose of this invention is to provide an EUV mask and its manufacturing method, so as to solve the technical problems of low production efficiency of EUV masks and the impact on the manufacturing cost of EUV masks in the traditional prior art.
[0006] To achieve the above objectives, the present invention provides a method for manufacturing an EUV mask, comprising the following steps: Provide transparent substrates; A molybdenum-silicon alternating layer is deposited on one side surface of a transparent substrate to form a reflective film; A protective layer is deposited on the reflective film, and the protective layer is formed of ruthenium. Patterned molybdenum / silicon focused ion beam scanning is performed on the protective layer and the reflective film to move ruthenium atoms in the protective layer, molybdenum atoms in part of the molybdenum layer in the reflective film, and molybdenum ions or silicon ions in the focused ion beam to the corresponding silicon layer in the scanned area, forming a patterned absorption layer. The patterned absorption layer is formed by molybdenum silicide containing ruthenium. A back conductive layer is deposited on the other side surface of the transparent substrate to form an EUV mask.
[0007] The aforementioned EUV mask manufacturing method involves patterning the protective layer and reflective film using a molybdenum / silicon focused ion beam scan. This causes ruthenium atoms in the protective layer, molybdenum atoms in some molybdenum layers of the molybdenum-silicon alternating layer, and molybdenum or silicon ions from the focused ion beam to move into the corresponding silicon layers, forming molybdenum silicides. This forms a patterned absorption layer composed of ruthenium-containing molybdenum silicides. The patterned absorption layer is directly formed after scanning, completing the EUV mask fabrication process. This eliminates the need for the absorption layer deposition process and complex absorption layer patterning steps such as coating and exposure required in traditional EUV mask manufacturing, significantly simplifying the EUV mask fabrication process and effectively improving EUV mask production efficiency and reducing manufacturing costs. Furthermore, the patterned absorption layer, formed by molybdenum silicides containing ruthenium, strongly absorbs 13.5nm EUV light, effectively ensuring absorption efficiency and pattern fidelity. The presence of ruthenium in the molybdenum silicides further reduces reflection in the absorption layer, contributing to further improved absorption efficiency. Furthermore, the EUV mask manufacturing method described above can adjust the molybdenum and silicon content in the final patterned absorption layer by selecting a suitable molybdenum / silicon focused ion beam and controlling the energy, flow rate, and scanning speed of the focused ion beam. During implementation, a suitable molybdenum focused ion beam or silicon focused ion beam is selected in advance based on the thickness of the silicon and molybdenum layers in the molybdenum-silicon alternating layer and the target molybdenum and silicon content in the desired patterned absorption layer. The energy, flow rate, and scanning speed of the focused ion beam are also set. After scanning, an absorption layer with the target molybdenum and silicon content can be accurately formed, which can further ensure the absorption efficiency of the absorption layer.
[0008] In summary, the above-mentioned EUV mask manufacturing method can effectively improve the production efficiency of EUV masks, save on the manufacturing cost of EUV masks, and effectively ensure the light absorption rate of the absorption layer, thus ensuring the stable and reliable performance of the EUV mask products.
[0009] In one embodiment, the step of patterning the protective layer and the reflective film using a molybdenum / silicon focused ion beam scan includes: Patterned molybdenum / silicon focused ion beam scanning is performed on the protective layer and reflective film to move molybdenum atoms from 5 to 10 molybdenum layers in the molybdenum-silicon alternating layer to the adjacent silicon layer.
[0010] In one embodiment, The thickness of the patterned absorption layer is no greater than 40 nm; or, From the upper surface of the patterned absorption layer to the surface where the patterned absorption layer contacts the molybdenum-silicon alternating layer, the width of the patterned absorption layer gradually narrows.
[0011] In one embodiment, The step of depositing an alternating molybdenum-silicon layer on one side surface of a transparent substrate includes: introducing a reaction gas into the deposition process, the reaction gas containing at least one element selected from carbon, oxygen, or nitrogen. or, The step of depositing a molybdenum-silicon alternating layer on one side surface of a transparent substrate includes: implanting at least one atom selected from carbon, nitrogen, or oxygen atoms into the silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer; or, The step of depositing a molybdenum-silicon alternating layer on one side surface of a transparent substrate includes: depositing an interface layer on the surface of the silicon layer and / or the molybdenum layer in the molybdenum-silicon alternating layer, the interface layer being formed of carbon.
[0012] In one embodiment, The silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer contain 1% to 2% of at least one element selected from carbon, oxygen, or nitrogen. or, The thickness of the interface layer is no more than 4nm.
[0013] In one embodiment, the step of patterning the protective layer and the reflective film with a molybdenum / silicon focused ion beam scan further includes: The protective layer and reflective film are graphically scanned to form alignment marks.
[0014] In one embodiment, The beam spot size of the molybdenum / silicon focused ion beam is no greater than 5 nm; or, The focusing temperature of the molybdenum / silicon focused ion beam is 400℃~800℃.
[0015] 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.
[0016] In one embodiment, after the step of forming the patterned absorption layer, the step further includes: performing a rapid thermal annealing treatment on the patterned absorption layer at a temperature of 400°C to 800°C.
[0017] On the other hand, the present invention also provides an EUV mask, which is manufactured using any of the EUV mask manufacturing methods described above. The EUV mask includes: a transparent substrate, a reflective film, a back conductive layer, a protective layer, and a patterned absorption layer. A reflective film is disposed on one side surface of the transparent substrate, and a back conductive layer is disposed on the other side surface. The reflective film includes a stacked reflective layer and a patterned reflective layer. The stacked reflective layer is disposed on the transparent substrate, and the patterned reflective layer is disposed on the stacked reflective layer. Both the stacked reflective layer and the patterned reflective layer include multiple layers of alternating molybdenum and silicon. A patterned absorption layer is disposed on the stacked reflective layer, and the patterned absorption layer and the patterned reflective layer are staggered. The patterned absorption layer is formed of a molybdenum silicide containing ruthenium. The protective layer is disposed on the patterned reflective layer.
[0018] The aforementioned EUV mask is manufactured using any of the EUV mask manufacturing methods described above. This EUV mask has the advantages of simple structure, high production efficiency, low production cost, and stable and reliable product performance.
[0019] In one embodiment, The patterned absorption layer contains at least one element selected from carbon, oxygen, or nitrogen. or, In a multilayer molybdenum-silicon alternating layer, the molybdenum layer and / or silicon layer contain at least one element selected from carbon, oxygen, or nitrogen. or, An interface layer is provided between the molybdenum layer and the silicon layer in a multilayer molybdenum-silicon alternating layer. Attached Figure Description
[0020] Figure 1 This is a flowchart illustrating an embodiment of an EUV mask manufacturing method. Figures 2 to 7 This is a schematic diagram of the structure of an EUV mask manufactured using the EUV mask manufacturing method of the present invention, according to one embodiment.
[0021] Explanation of reference numerals in the attached figures: 10-Transparent substrate, 20-Reflective film, 21-Stacked reflective layer, 22-Patterned reflective layer, 30-Protective layer, 40-Back conductive layer, 50-Patterned absorption layer, 60-Molybdenum focused ion beam, 70-Alignment mark, 80-EUV mask. 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 An embodiment of an EUV mask manufacturing method 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 molybdenum-silicon alternating layer on one side surface of the transparent substrate to form a reflective film 20.
[0027] Specifically, molybdenum and silicon layers (or silicon and molybdenum layers) are sequentially and alternately deposited on a transparent substrate to form a multilayer reflective Bragg stack as a reflective film 20. Each molybdenum or silicon layer has a single-layer thickness of 3nm~4nm, and each pair is approximately 6.75nm thick. This can be achieved by deposition processes such as CVD, PECVD, PVD, or ALD, forming 40-50 cycles to create the reflective film 20 (e.g., ...). Figure 3 (As shown).
[0028] Step S13: Deposit a protective layer 30 on the reflective film 20. The protective layer 30 is formed of ruthenium.
[0029] Specifically, the protective layer 30 is preferably formed of ruthenium (Ru), and its thickness is preferably 2nm-4nm. Further, the protective layer 30 is preferably formed on the surface of the reflective film 20 by deposition processes such as CVD, PECVD, PVD, and ALD (e.g., Figure 4 (As shown).
[0030] Step S14: Patterned molybdenum focused ion beam 60 scans the protective layer 30 and the reflective film 20, causing ruthenium atoms in the protective layer 30, molybdenum atoms in a portion of the molybdenum layer in the reflective film 20, and molybdenum ions in the molybdenum focused ion beam 60 to move to the corresponding silicon layer in the scanned area, forming a patterned absorption layer 50. The patterned absorption layer 50 is formed by molybdenum silicide containing ruthenium.
[0031] Specifically, such as Figure 5 , Figure 6As shown, during the patterned molybdenum focused ion beam 60 scanning of the protective layer 30 and the reflective film 20, the energy of the molybdenum focused ion beam 60 enables molybdenum atoms in a portion of the molybdenum layer in the reflective film 20 located within the scanning area to rapidly migrate to the adjacent silicon layer and react with silicon to form molybdenum silicides. Simultaneously, the energy of the molybdenum focused ion beam 60 also enables molybdenum ions and ruthenium atoms in the protective layer to migrate to the corresponding silicon layer, forming a patterned absorption layer 50 composed of molybdenum silicides containing ruthenium. Correspondingly, a portion of the molybdenum-silicon alternating layer in the region not scanned by the molybdenum focused ion beam 60 does not react, forming a patterned reflective layer 22. Furthermore, the energy of the molybdenum focused ion beam only causes a portion of the molybdenum layer near the protective film 30 to react with the silicon layer, while the portion of the molybdenum layer far from the protective film 30 does not react with the silicon layer, forming a stacked reflective layer 21. In this embodiment, the molybdenum and silicon content in the final patterned absorption layer 50 can be adjusted by controlling the energy, flow rate, and scanning speed of the molybdenum focused ion beam 60. During the implementation process, the energy, flow rate, and scanning speed of the molybdenum focused ion beam 60 are set in advance according to the thickness of the silicon layer and the molybdenum layer in the molybdenum-silicon alternating layer and the target molybdenum and silicon content in the patterned absorption layer 50 required. After the scan is completed, a molybdenum silicide layer with the target molybdenum and silicon content can be accurately formed.
[0032] The EUV mask manufacturing method of this embodiment can adjust the content of Mo and Si in the final patterned absorption layer 50 by controlling the energy, flow rate and scanning speed of the molybdenum focused ion beam 60. The adjustment of the Mo and Si content in the patterned absorption layer 50 is simple and convenient.
[0033] Furthermore, in one embodiment, step S14 further includes the following step: performing a patterned scan of the protective layer and the reflective film to form the alignment mark 70. In this embodiment, the patterned scan of the alignment mark 70 is completed simultaneously during the patterned molybdenum focused ion beam 60 scan of the protective layer and the reflective film, eliminating the need for separate exposure to form the alignment mark 70, which helps to improve the production efficiency of the EUV mask 80.
[0034] Step S15: Deposit a back conductive layer 40 on the other side surface of the transparent substrate to form an EUV mask 80.
[0035] Specifically, after forming the patterned absorption layer 50, a back conductive layer 40 is deposited on the other side surface of the transparent substrate to form an EUV mask 80 (e.g., ...). Figure 7 As shown in the figure, the EUV mask 80 is prepared. Preferably, the back conductive layer 40 is formed of materials such as Cr, Cr oxide, or Cr nitride.
[0036] In one embodiment, step S12 includes: introducing a reactive gas into the deposition process, the reactive gas containing at least one element selected from carbon, oxygen, or nitrogen. Specifically, a reactive gas is introduced during the deposition of the silicon layer in the molybdenum-silicon alternating layer, the reactive gas containing at least one element selected from carbon, oxygen, or nitrogen, to form a silicon layer containing at least one element selected from carbon, oxygen, or nitrogen; and / or, a reactive gas is introduced during the deposition of the molybdenum layer in the molybdenum-silicon alternating layer, the reactive gas containing at least one element selected from carbon, oxygen, or nitrogen, to form a molybdenum layer containing at least one element selected from carbon, oxygen, or nitrogen. Preferably, in one embodiment, the silicon layer and / or the molybdenum layer in the molybdenum-silicon alternating layer contain 1% to 2% of at least one element selected from carbon, oxygen, or nitrogen. In this embodiment, 1% to 2% of at least one element selected from carbon, oxygen, or nitrogen is added to the silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer. Carbon, oxygen, or nitrogen can suppress the interdiffusion of molybdenum ions and Si, thereby suppressing the lateral diffusion of molybdenum ions. The vertical diffusion of molybdenum ions is mainly controlled by the energy, flux, and scanning speed of the molybdenum focused ion beam 60, and is not affected by the suppression of carbon, oxygen, or nitrogen. This further suppresses the lateral silicide formation of molybdenum silicides, ensuring that the molybdenum silicide layer is formed only in the scanning area of the molybdenum focused ion beam 60. This effectively reduces the edge roughness of the patterned absorption layer 50 and effectively ensures the exposure accuracy of the EUV mask 80. Simultaneously, adding at least one element selected from carbon, oxygen, or nitrogen to the molybdenum layer and / or silicon layer in the molybdenum-silicon alternating layer can also suppress the interdiffusion between the molybdenum and silicon layers, preventing interlayer diffusion between the molybdenum and silicon layers from affecting the reflectivity of the reflective film and effectively ensuring that the reflective film maintains a stable high reflectivity. Furthermore, the patterned absorption layer 50 formed in this embodiment contains carbon, oxygen or nitrogen elements, which can further enhance the light absorption rate of the patterned absorption layer 50 and help enhance the adhesion between the patterned absorption layer 50 and the molybdenum-silicon alternating layer interface.
[0037] This embodiment achieves the addition of at least one element selected from carbon, oxygen, or nitrogen to the silicon and / or molybdenum layers in a molybdenum-silicon alternating layer by introducing a reactive gas during the deposition process. It should be noted that this embodiment is not intended to specifically limit the method of adding carbon, oxygen, or nitrogen to the silicon and / or molybdenum layers. For example, in another embodiment, carbon, oxygen, or nitrogen can also be added to the silicon and / or molybdenum layers via atom implantation. Specifically, in another embodiment, step S12 includes implanting at least one atom selected from carbon, nitrogen, or oxygen into the silicon and / or molybdenum layers in the molybdenum-silicon alternating layer. Specifically, after the silicon or molybdenum layer deposition is completed, implanting at least one atom selected from carbon, nitrogen, or oxygen into the silicon or molybdenum layer suppresses lateral silicide formation of the molybdenum silicide and interlayer diffusion between the molybdenum and silicon layers.
[0038] Furthermore, in another embodiment, step S12 includes: depositing an interface layer on the surface of the silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer, the interface layer being formed of carbon. Specifically, an interface layer formed of carbon is deposited on the surface of the silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer. During the patterned molybdenum focused ion beam 60 scanning of the protective layer and reflective film, the energy of the molybdenum focused ion beam 60 can disperse the interface layer, causing carbon atoms to rapidly move into the silicon layer, thereby adding carbon elements to the silicon layer to suppress the lateral silicide of molybdenum silicide and the interlayer diffusion between the molybdenum layer and the silicon layer. In this embodiment, to ensure that the molybdenum focused ion beam 60 can completely disperse the interface layer, the thickness of the interface layer is preferably no greater than 4 nm.
[0039] In one embodiment, the step of patterning the protective layer 30 and the reflective film 20 by scanning with a molybdenum focused ion beam 60 includes: scanning the protective layer 30 and the reflective film 20 with a patterned molybdenum focused ion beam 60, causing molybdenum atoms in 5 to 10 molybdenum layers in the molybdenum-silicon alternating layer to move into adjacent silicon layers. Specifically, the patterned molybdenum focused ion beam 60 scan only causes 5 to 10 pairs of molybdenum-silicon layers close to the protective layer 30 to react. The molybdenum and silicon layers in the 5 to 10 pairs of molybdenum-silicon layers located within the scanning area react to form a patterned absorption layer 50. The molybdenum and silicon layers in the 5 to 10 pairs of molybdenum-silicon layers in the area not scanned by the molybdenum focused ion beam 60 do not react, forming a patterned reflective layer 22. Further, below the 5 to 10 pairs of molybdenum-silicon layers, the molybdenum and silicon layers in other molybdenum-silicon layers far from the protective layer 30 are not affected by the energy of the molybdenum focused ion beam 60, and the molybdenum and silicon layers do not react. This portion of the molybdenum-silicon alternating layer does not change, forming a stacked reflective layer 21.
[0040] Furthermore, calculations show that the patterned molybdenum silicide layer adds 1% of the original silicon layer thickness to the surface of the original silicon layer. The final thickness of the patterned molybdenum silicide layer is almost equal to the original silicon layer thickness. Therefore, by controlling the number of molybdenum layers in the molybdenum-silicon alternating layer where molybdenum atom transfer occurs, the thickness of the patterned absorption layer 50 can be well controlled. In this embodiment, a patterned molybdenum focused ion beam 60 scans 5-10 pairs of molybdenum-silicon layers in the molybdenum-silicon alternating layer, causing molybdenum atoms from only 5-10 molybdenum layers to move to adjacent silicon layers to form the patterned absorption layer 50. This effectively reduces the thickness of the patterned absorption layer 50 to suppress the 3D effect. Preferably, the thickness of the patterned absorption layer 50 is no greater than 40 nm. Compared to the traditional absorption layer thickness of 50 nm to 70 nm, the patterned absorption layer 50 in this embodiment significantly reduces the 3D effect, ensuring higher fidelity photolithography patterns. Furthermore, to suppress the 3D effect as much as possible, in one embodiment, the thickness of the patterned absorption layer 50 is preferably no greater than 30 nm. The EUV mask manufacturing method of this embodiment can effectively control the thickness of the patterned absorption layer 50. While ensuring sufficient optical contrast, it can minimize the thickness of the patterned absorption layer 50, thereby suppressing the 3D effect to the greatest extent and obtaining a higher fidelity lithographic pattern. This method can well meet the development requirements of thinner absorption layers for EUV masks.
[0041] In one embodiment, the width of the patterned absorption layer 50 gradually narrows from its upper surface to the surface where it contacts the molybdenum-silicon alternating layer. Specifically, during the patterning scanning process, the temperature gradually decreases downwards. Due to the decrease in local temperature, the edge contour of the molybdenum-siliconized region gradually shrinks inwards, thereby forming inclined sidewalls in the patterned absorption layer 50. Thus, the width of the patterned absorption layer 50 gradually narrows from its upper surface to the surface (i.e., the lower surface) where it contacts the molybdenum-silicon alternating layer. The patterned absorption layer 50 of this embodiment has inclined sidewalls, and the sidewalls of the patterned absorption layer 50 gradually contract inward from the upper surface to the lower surface. For incident light incident obliquely into the reflection area, the inclination direction of the sidewall of the absorption layer on one side of the reflection area is opposite to the incident direction of the incident light, which does not affect the transmission of the incident and reflected light. The inclination direction of the sidewall of the absorption layer on the other side of the reflection area is the same as the incident direction of the incident light. The sidewalls of the absorption layer are approximately parallel or parallel to the incident light, which can minimize the impact on the transmission of the incident and reflected light, so that the reflection area receives and reflects more light, which can significantly improve the output of reflected light, help enhance the reflection intensity of the reflection area, and improve the resolution. Therefore, the patterned absorption layer 50 formed by the EUV mask manufacturing method of this embodiment can effectively achieve 3D scattering effect, while also enhancing the reflection intensity of the EUV mask 80 and improving the imaging resolution, which is beneficial to further improving the product performance of the EUV mask 80.
[0042] The EUV mask manufacturing method of this embodiment directly forms a patterned absorption layer 50 by directly writing a patterned scan of the protective layer and the reflective film using a molybdenum focused ion beam 60. To achieve optimal pattern control, the scanning area of the molybdenum focused ion beam 60 needs to be adjusted according to the pattern size. To ensure that the scanning area of the molybdenum focused ion beam 60 matches the image size and meets the patterning requirements, in one embodiment, the beam spot size of the molybdenum focused ion beam 60 is no greater than 5 nm.
[0043] In one embodiment, to facilitate the reaction of molybdenum ions and molybdenum atoms in the molybdenum layer with the silicon layer and to prevent material evaporation, the focusing temperature of the molybdenum focused ion beam 60 is set at 400°C to 800°C. At temperatures of 400°C to 800°C, molybdenum ions and molybdenum atoms in the molybdenum layer tend to migrate into the silicon layer and form molybdenum silicides. More preferably, to ensure complete reaction between molybdenum and silicon, the focusing temperature of the molybdenum focused ion beam 60 is controlled at 500°C to 800°C.
[0044] In one embodiment, to ensure that the small-spot molybdenum focused ion beam 60 has sufficient energy to rapidly form the patterned absorption layer 50, the focusing temperature of the molybdenum focused ion beam 60 is ensured to instantly reach 400°C. o C-800 oC. The energy of the molybdenum focused ion beam 60 is 1eV-100eV, the flux is 0.1mA-100mA, and the scanning speed is 0.1mm / s-100mm / s.
[0045] In one embodiment, after forming the patterned absorber layer 50, the step further includes performing a rapid thermal annealing process on the patterned absorber layer 50. This embodiment ensures complete reaction between molybdenum and silicon by performing a rapid thermal annealing process on the patterned absorber layer 50. Preferably, in one embodiment, the rapid thermal annealing temperature is 400°C to 800°C.
[0046] The EUV mask manufacturing method of the above embodiment uses a molybdenum focused ion beam 60 to pattern the protective layer 30 and the reflective film 20 to form a patterned absorption layer 50. In another embodiment, a silicon focused ion beam can also be used to pattern the protective layer 30 and the reflective film 20 to form a patterned absorption layer 50. During the patterned silicon focused ion beam scanning of the protective layer 30 and the reflective film 20, the energy of the silicon focused ion beam can cause molybdenum atoms in a portion of the molybdenum layer in the reflective film located in the scanning area to rapidly move to the silicon layer adjacent to the corresponding molybdenum layer and react with silicon to form molybdenum silicide. At the same time, the energy of the silicon focused ion beam can also cause silicon ions and ruthenium atoms in the protective layer to move to the corresponding silicon layer to form molybdenum silicide containing ruthenium. Specifically, when it is necessary to form a molybdenum-rich patterned absorption layer 50, it is preferable to use a molybdenum focused ion beam 60 for patterning scanning; when it is necessary to form a silicon-rich patterned absorption layer 50, it is preferable to use a silicon focused ion beam for patterning scanning. Furthermore, after selecting a specific molybdenum focused ion beam 60 or silicon focused ion beam, the energy, flux, and scanning speed of the molybdenum focused ion beam 60 or silicon focused ion beam are set according to the thickness of the silicon and molybdenum layers in the molybdenum-silicon alternating layer and the target molybdenum and silicon content in the required patterned absorption layer 50. This allows for the accurate formation of a molybdenum silicide layer with the target molybdenum and silicon content. In summary, in practical applications, a suitable molybdenum focused ion beam 60 or silicon focused ion beam can be selected for patterned scanning according to specific needs; this embodiment does not impose specific limitations.
[0047] Further, in one embodiment, to achieve optimal pattern control and ensure that the scanning area of the silicon focused ion beam matches the image size to meet the patterning requirements, the beam spot size of the silicon focused ion beam is preferably no greater than 5 nm. More further, in one embodiment, to enable the reaction of Si ions and molybdenum atoms in the molybdenum layer with the silicon layer and to prevent material evaporation, the focusing temperature of the silicon focused ion beam is 400℃~800℃. At a temperature of 400℃~800℃, Si ions and molybdenum atoms in the molybdenum layer tend to migrate into the silicon layer and form molybdenum silicides. More preferably, to ensure complete reaction between silicon and molybdenum, the focusing temperature of the silicon focused ion beam is controlled at 500℃~800℃. Even further, in one embodiment, to ensure that the small-spot silicon focused ion beam has sufficient energy to rapidly form the patterned absorption layer 50, the focusing temperature of the silicon focused ion beam is ensured to instantaneously reach 400℃. o C-800 o C. The energy of the silicon focused ion beam is 10eV-100eV, the flux is 0.1mA-100mA, and the scanning speed is 0.1mm / s-100mm / s.
[0048] It should be noted that the EUV mask manufacturing method in this embodiment differs from the EUV mask manufacturing method in the above embodiment only in that a silicon focused ion beam is used instead of the molybdenum focused ion beam 60 in the above embodiment to perform patterning scanning on the protective layer 30 and the reflective film 20. Apart from the difference between the silicon focused ion beam and the molybdenum focused ion beam 60, the other steps in this embodiment and the structure of the EUV mask produced by the EUV mask manufacturing method in this embodiment are the same as those in the above embodiment, and will not be described in detail here.
[0049] The aforementioned EUV mask manufacturing method involves patterning the protective layer 30 and the reflective film 20 using a molybdenum / silicon focused ion beam scan. This causes ruthenium atoms in the protective layer, molybdenum atoms in some molybdenum layers of the molybdenum-silicon alternating layer, and molybdenum or silicon ions from the focused ion beam to move into the corresponding silicon layers, forming molybdenum silicides. This forms a patterned absorption layer 50 composed of molybdenum silicides containing ruthenium. The patterned absorption layer 50 is directly formed after scanning, completing the EUV mask 80 fabrication. This eliminates the need for the absorption layer deposition process and complex absorption layer patterning steps such as coating and exposure required in traditional EUV mask 80 manufacturing processes, significantly simplifying the EUV mask 80 fabrication process and effectively improving EUV mask 80 production efficiency, thus saving manufacturing costs. Furthermore, the patterned absorption layer 50, formed from molybdenum silicides containing ruthenium, strongly absorbs 13.5nm EUV light, effectively ensuring absorption efficiency and pattern fidelity. Furthermore, the presence of ruthenium in molybdenum silicides can further reduce reflection in the absorption layer, thus contributing to improved absorption efficiency. Moreover, the aforementioned EUV mask manufacturing method, by selecting a suitable molybdenum / silicon focused ion beam and controlling its energy, flow rate, and scanning speed, can adjust the molybdenum and silicon content in the final patterned absorption layer 50. During implementation, a suitable molybdenum focused ion beam 60 or silicon focused ion beam is selected in advance based on the thickness of the silicon and molybdenum layers in the molybdenum-silicon alternating layer and the desired molybdenum and silicon content in the patterned absorption layer 50. The energy, flow rate, and scanning speed of the focused ion beam are then set. After scanning, an absorption layer with the target molybdenum and silicon content can be accurately formed, further ensuring the absorption efficiency of the absorption layer.
[0050] In summary, the above-mentioned EUV mask manufacturing method can effectively improve the production efficiency of EUV mask 80, save the manufacturing cost of EUV mask 80, and effectively ensure the light absorption rate of the absorption layer, ensuring the stable and reliable performance of EUV mask 80.
[0051] Please refer to the following: Figure 7The present invention also provides an EUV mask 80, which is manufactured using the EUV mask manufacturing method of any of the above embodiments. The EUV mask 80 includes: a transparent substrate 10, a reflective film 20, a back conductive layer 40, a protective layer 30, and a patterned absorption layer 50. The reflective film 20 is disposed on one side surface of the transparent substrate 10, and the back conductive layer 40 is disposed on the other side surface. The reflective film 20 includes a stacked reflective layer 21 and a patterned reflective layer 22. The stacked reflective layer 21 is disposed on the transparent substrate 10, and the patterned reflective layer 22 is disposed on the stacked reflective layer 21. Both the stacked reflective layer 21 and the patterned reflective layer 22 include multiple alternating molybdenum-silicon layers. The patterned absorption layer 50 is disposed on the stacked reflective layer 21, and the patterned absorption layer 50 and the patterned reflective layer 22 are staggered. The patterned absorption layer 50 is formed of a molybdenum silicide containing ruthenium. The protective layer 30 is disposed on the patterned reflective layer 22.
[0052] The EUV mask 80 of this embodiment is manufactured using the EUV mask manufacturing method of any of the above embodiments. This EUV mask 80 has the advantages of simple structure, high production efficiency, low production cost, and stable and reliable product performance. Furthermore, this EUV mask 80 can greatly suppress 3D effects while ensuring sufficient optical contrast, and can obtain higher fidelity lithographic patterns, thus well meeting the development requirements of EUV lithography technology.
[0053] In one embodiment, in the multilayer molybdenum-silicon alternating layers of the stacked reflective layer 21 and the patterned reflective layer 22, an interface layer is provided between adjacent molybdenum and silicon layers; or, the molybdenum and / or silicon layers contain at least one element selected from carbon, oxygen, or nitrogen. Preferably, the molybdenum and / or silicon layers contain 1% to 2% of at least one element selected from carbon, oxygen, or nitrogen. This embodiment, by providing an interface layer between the molybdenum and silicon layers, or by adding at least one element selected from carbon, oxygen, or nitrogen to the molybdenum and / or silicon layers, can effectively suppress the interdiffusion between the molybdenum and silicon layers, avoiding interlayer diffusion that could affect the reflectivity of the reflective film 20, and effectively ensuring that the reflective film 20 maintains a stable high reflectivity. Further, in one embodiment, the patterned absorption layer 50 contains at least one element selected from carbon, oxygen, or nitrogen, and the patterned metal silicide layer contains carbon, oxygen, or nitrogen, which can further enhance the light absorption of the patterned absorption layer 50 and improve the interfacial adhesion between the patterned absorption layer 50 and the stacked reflective layer 21.
[0054] 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 EUV mask, characterized in that, Includes the following steps: Provide transparent substrates; A molybdenum-silicon alternating layer is deposited on one side surface of the transparent substrate to form a reflective film; A protective layer is deposited on the reflective film, the protective layer being formed of ruthenium; Patterned molybdenum / silicon focused ion beam scanning is performed on the protective layer and the reflective film to move ruthenium atoms in the protective layer, molybdenum atoms in a portion of the molybdenum layer in the reflective film, and molybdenum ions or silicon ions in the focused ion beam to the corresponding silicon layer in the scanned area, forming a patterned absorption layer. The patterned absorption layer is formed by molybdenum silicide containing ruthenium. A back conductive layer is deposited on the other side surface of the transparent substrate to form an EUV mask.
2. The EUV mask manufacturing method according to claim 1, characterized in that, The steps of patterning the protective layer and the reflective film using molybdenum / silicon focused ion beam scanning include: Patterned molybdenum / silicon focused ion beam scanning is performed on the protective layer and the reflective film to move molybdenum atoms in 5 to 10 layers of molybdenum in the molybdenum-silicon alternating layer into the adjacent silicon layer.
3. The EUV mask manufacturing method according to claim 1, characterized in that, The thickness of the patterned absorption layer is no greater than 40 nm; or, From the upper surface of the patterned absorption layer to the surface where the patterned absorption layer contacts the molybdenum-silicon alternating layer, the width of the patterned absorption layer gradually narrows.
4. The EUV mask manufacturing method according to claim 1, characterized in that, The step of depositing an alternating molybdenum-silicon layer on one side surface of the transparent substrate includes: introducing a reactive gas into the deposition process, the reactive gas containing at least one element selected from carbon, oxygen, or nitrogen. or, The step of depositing a molybdenum-silicon alternating layer on one side surface of the transparent substrate includes: implanting at least one atom selected from carbon, nitrogen, or oxygen atoms into the silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer; or, The step of depositing a molybdenum-silicon alternating layer on one side surface of the transparent substrate includes depositing an interface layer on the surface of the silicon layer and / or the molybdenum layer in the molybdenum-silicon alternating layer, the interface layer being formed of carbon.
5. The EUV mask manufacturing method according to claim 4, characterized in that, The silicon layer and / or molybdenum layer in the molybdenum-silicon alternating layer contain 1% to 2% of at least one element selected from carbon, oxygen, or nitrogen. or, The thickness of the interface layer is no greater than 4 nm.
6. The EUV mask manufacturing method according to claim 1, characterized in that, The step of patterning the protective layer and the reflective film with molybdenum / silicon focused ion beam scanning further includes: The protective layer and the reflective film are subjected to a graphical scan of alignment marks to form alignment marks.
7. The EUV mask manufacturing method according to claim 1, characterized in that, The beam spot size of the molybdenum / silicon focused ion beam is no greater than 5 nm; or, The focusing temperature of the molybdenum / silicon focused ion beam is 400℃~800℃.
8. The EUV mask 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.
9. The EUV mask manufacturing method according to claim 1, characterized in that, After the step of forming the patterned absorption layer, the method further includes the following step: performing a rapid thermal annealing treatment on the patterned absorption layer, wherein the rapid thermal annealing treatment temperature is 400℃~800℃.
10. An EUV mask, characterized in that, The EUV mask is manufactured using the EUV mask manufacturing method according to any one of claims 1 to 9. The EUV mask includes: a transparent substrate, a reflective film, a back conductive layer, a protective layer, and a patterned absorption layer. The reflective film is disposed on one side surface of the transparent substrate, and the back conductive layer is disposed on the other side surface. The reflective film includes a stacked reflective layer and a patterned reflective layer. The stacked reflective layer is disposed on the transparent substrate, and the patterned reflective layer is disposed on the stacked reflective layer. Both the stacked reflective layer and the patterned reflective layer include multiple alternating molybdenum-silicon layers. The patterned absorption layer is disposed on the stacked reflective layer, and the patterned absorption layer and the patterned reflective layer are staggered. The patterned absorption layer is formed of a molybdenum silicide containing ruthenium. The protective layer is disposed on the patterned reflective layer.
11. The EUV mask according to claim 10, characterized in that, The patterned absorption layer contains at least one element selected from carbon, oxygen, or nitrogen. or, The molybdenum layer and / or silicon layer in the multilayer molybdenum-silicon alternating layer contain at least one element selected from carbon, oxygen or nitrogen. or, An interface layer is provided between the molybdenum layer and the silicon layer in the multilayer molybdenum-silicon alternating layer.