Micro-nano scale pattern processing method
A protective polymer coating in FIB processing addresses the challenges of nanoscale structure complexity and precision by reducing damage and re-deposition, resulting in improved micro-nano structure uniformity and surface quality.
Patent Information
- Application Number
- CN202510528709.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-07-15
AI Technical Summary
In the process of nanostructure array density, feature size miniaturization and shape complexity, existing focusing ion beam processing technology is difficult to effectively protect the metal film layer, resulting in damage to non-processed areas and redeposition effects affecting the pattern quality.
A polymer coating is formed on the surface of the metal film layer, and the metal film layer is protected by a polymer coating, a focusing ion beam processing is used to form a micro-nanoscale pattern, and the polymer coating is removed after completion.
Effectively protect the metal film layer, reduce damage in non-processed areas, slow down the redeposition effect, and improve the uniformity of micro-nanoscale patterns and surface morphology quality.
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Figure CN120308911A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of micro-nano processing technologies, and particularly to a method for processing micro-nano scale patterns. Background Art
[0002] Nanomanufacturing technology plays an important role in nanoscience research and national major needs. It is an important technology for manufacturing at the nanoscale and has unique advantages in fields such as transmission electron microscope sample preparation, integrated circuit device failure analysis, internal structure characterization of materials, and three-dimensional micro-nano structure processing. For example, in the research and production of semiconductor integrated circuits, focused ion beam processing has become an indispensable core link. Focused ion beam (FIB) processing can achieve the diagnosis and repair of integrated circuit chips and the repair of optical mask defects. The liquid ion source is accelerated and focused by an electrostatic lens into an ion beam with a diameter at the nanoscale to achieve high-precision processing of nanostructures. Compared with traditional technologies, focused ion beam has obvious advantages in the field of micro-nano processing: first, it can perform direct writing processing on structures with nanoscale feature sizes; second, it can achieve micro-nano processing of different materials and complex shapes; third, compared with traditional mechanical processing methods, the damage to the processing substrate during focused ion beam processing and manufacturing is very small.
[0003] Currently, the densification of nanostructure arrays, the miniaturization of nanostructure feature sizes, and the complication of nanostructure shapes have become three development trends in focused ion beam processing. The density of nanostructures is increasing, and the requirements for structure feature sizes and shapes are getting higher. With the continuous improvement of application requirements and processing parameter indicators, it poses severe challenges to the manufacturing methods and processes of focused ion beams. How to solve these problems not only involves manufacturing process issues but also scientific issues such as the basis of focused ion beam nanomanufacturing. Summary of the Invention
[0004] In view of the above problems, the present disclosure provides a method for processing micro-nano scale patterns to at least partially solve the above technical problems.
[0005] According to an embodiment of the present disclosure, a method for processing micro-nano scale patterns includes: forming a metal film layer on the surface of a substrate; forming a polymer coating on the surface of the metal film layer, and the polymer coating is used to protect the metal film layer during the processing; using a focused ion beam processing method to perform micro-nano scale pattern processing on the metal film layer with the polymer coating formed on its surface, and after the processing is completed, removing the polymer coating to form a micro-nano scale pattern on the metal film layer.
[0006] According to an embodiment of the present disclosure, the material of the polymer coating is a material that does not react with the metal and can be removed after the processing is completed.
[0007] According to an embodiment of the present disclosure, the material of the polymer coating includes one of photoresist, silica gel, spin-on glass, epoxy resin, polyurethane, and graphene.
[0008] According to an embodiment of the present disclosure, the thickness of the polymer coating is 20 nm to 200 nm.
[0009] According to an embodiment of the present disclosure, the material of the metal film layer includes one of chromium, gold, platinum, silver, tantalum, indium, molybdenum, and aluminum.
[0010] According to an embodiment of the present disclosure, the thickness of the metal film layer is 40 nm to 10 μm.
[0011] According to an embodiment of the present disclosure, the ion source used in the focused ion beam processing method is a gallium metal ion source or a helium ion source.
[0012] According to an embodiment of the present disclosure, the material of the substrate includes silicon or quartz glass.
[0013] According to an embodiment of the present disclosure, the line width of the micro-nano scale pattern is 20 nm to 40 nm.
[0014] The micro-nano scale pattern processing method provided by the present disclosure has at least the following technical effects:
[0015] Before performing focused ion beam processing, a polymer coating is pre-formed on the metal film layer. In this way, the metal film layer is protected during focused ion beam processing, avoiding damage to the metal film layer in the non-processing area caused by unstable ion beam power, which leads to an increase in roughness. At the same time, the redeposited metal atoms are deposited on the polymer coating rather than on the metal film layer, slowing down the uneven deposition of atoms on the micro-nano scale pattern caused by the redeposition effect, and improving the uniformity of the micro-nano scale pattern. At the same time, the surrounding area of the micro-nano scale pattern is protected, reducing the surface roughness of the film layer in the surrounding area, and improving the pattern quality of the micro-nano scale pattern. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above content and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:
[0017] Figure 1 Schematically shows a flowchart of a micro-nano scale pattern processing method according to an embodiment of the present disclosure;
[0018] Figure 2 Schematically shows a schematic diagram of a micro-nano scale pattern processing method according to an embodiment of the present disclosure;
[0019] Figure 3Schematically shows a comparison diagram of the effects with and without a polymer coating protection on a metal film layer according to an embodiment of the present disclosure;
[0020] Figure 4 Schematically shows a comparison diagram of the effect of a polymer coating on reducing the redeposition effect according to an embodiment of the present disclosure;
[0021] Figure 5 Schematically shows the morphology of the film layer around the pattern with and without polymer coating protection according to an embodiment of the present disclosure. Detailed implementation manners
[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.
[0023] In the process of implementing the present disclosure, it is found that: when using the focused ion beam processing technology for processing, the focused ion beam bombards the solid material, and during the process that the atoms of the solid material are sputtered out of the surface, some atoms will fall back to the sample surface, and this process is called redeposition. The usual focused ion beam processing etching strategy is to use a very short dwell time and scan multiple times to reduce the influence of redeposition on the processed structure. Increasing the dwell time of the ion beam at each point will enhance the influence of redeposition. Due to surface thermodynamics and kinetics reasons, the probability that the redeposited atoms fall into the depressions is higher, so it can play a role in partially flattening the surface, thereby improving the flatness of the etched bottom surface. However, for micro-nano scale patterns, the redeposited atoms will fall on the micro-nano scale patterns, affecting the surface morphology and roughness of the micro-nano scale patterns.
[0024] In view of this, an embodiment of the present disclosure provides a micro-nano scale pattern processing method, which obtains high-quality micro-nano scale patterns by protecting the metal film layer and reducing the redeposition effect.
[0025] Figure 1 Schematically shows a flowchart of the micro-nano scale pattern processing method according to an embodiment of the present disclosure.
[0026] As Figure 1 shown, the micro-nano scale pattern processing method of this embodiment may include operation S110 to operation S130.
[0027] In operation S110, a metal film layer is formed on the substrate surface.
[0028] In operation S120, a polymer coating is formed on the surface of the metal film layer, and the polymer coating is used to protect the metal film layer during the processing.
[0029] In operation S130, a focused ion beam processing method is used to perform micro-nano scale patterning on the metal film layer with a polymer coating formed on its surface. After the processing is completed, the polymer coating is removed, and a micro-nano scale pattern is formed on the metal film layer.
[0030] Figure 2 The schematic diagram of the micro-nano scale patterning method according to an embodiment of the present disclosure is schematically shown.
[0031] As Figure 2 shown in a, when no polymer coating is formed on the metal film layer, the metal layer is etched using FIB. Due to the instability of the ion beam power, the film layer in the non-processing area is damaged, that is, the size D1 of the etched interface structure (triangle in the figure) is larger. And the redeposited metal atoms will be deposited on the metal film layer.
[0032] As Figure 2 shown in b, when a polymer coating is formed on the metal film layer, the metal layer is etched using FIB. Even if the ion beam power is unstable, due to the protective effect of the polymer coating, damage to the film layer in the non-processing area can be avoided, that is, the size D2 of the etched interface structure (triangle in the figure) is smaller. And the redeposited metal atoms will not be deposited on the metal film layer, but on the polymer coating.
[0033] According to an embodiment of the present disclosure, the line width D2 of the micro-nano scale pattern is 20 nm to 40 nm, while the line width D1 without covering the polymer coating under the same process parameters is 40 nm to 60 nm.
[0034] Thus, through the micro-nano scale patterning method of the embodiment of the present disclosure, in the micro-nano scale pattern area, since the size of the micro-nano scale pattern is close to the resolution limit of the ion beam, the stability of the ion beam will affect the quality of the pattern. By adding a polymer coating, when the ion beam drifts, it acts on the polymer coating rather than the metal film layer. At the same time, during the processing, the metal film layer sputtered by the high-energy ion beam is redeposited on the polymer coating rather than the metal film layer where it is located. The polymer coating can then be simply washed off, avoiding the increase in roughness caused by damage to the film layer in the non-processing area due to the instability of the ion beam power, slowing down the redeposition effect, and the uneven situation caused by the deposition of atoms on the metal pattern, improving the pattern uniformity, thereby improving the surface morphology of the pattern and the line edge roughness.
[0035] In some embodiments, the material of the substrate may include but is not limited to one of silicon and quartz glass. The specific type can be selected according to actual needs, and the present disclosure does not make any limitations.
[0036] In some embodiments, the material of the metal film layer may include, but is not limited to, one of chromium, gold, platinum, silver, tantalum, indium, molybdenum, and aluminum. The specific type can be selected according to actual needs, and the present disclosure does not limit it.
[0037] In some embodiments, the thickness of the metal film layer is 40 nm to 10 μm. For example, the thickness of the metal film layer is 40 nm, 80 nm, 120 nm, and so on.
[0038] In some embodiments, the material of the polymer coating is a material that does not react with the metal and can be removed after processing.
[0039] According to the embodiments of the present disclosure, for metal materials, during focused ion beam processing, the metal ion source is prone to alloying reaction with the metal film layer. Therefore, in order to better protect the metal film layer, the formed polymer coating does not react with the metal, thus playing a protective role. The material of the polymer coating is selected as a material that is easily removed after processing to reduce the complexity of the process.
[0040] It should be noted that for metal materials, during focused ion beam processing, the metal ion source is prone to alloying reaction with the metal film layer, so the processing rate is fast and the efficiency is high; while for non-metal materials, the processing rate during focused ion beam processing is slower and the pattern is more uniform. This method utilizes the difference in the processing rates of focused ion beams for different types of material films, and by adding an easily removable polymer coating on the metal film layer as a protective layer, it protects the metal film layer from being damaged by the focused ion beam and slows down the re-deposition effect of metal atoms.
[0041] In some embodiments, the material of the polymer coating may include, but is not limited to, one of photoresist, silica gel, spin-on glass, epoxy resin, polyurethane, and graphene. The specific type can be selected according to actual needs, and the present disclosure does not limit it.
[0042] In some embodiments, the thickness of the polymer coating is 20 nm to 200 nm. For example, the thickness of the polymer coating is 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm, 200 nm, etc.
[0043] In some embodiments, the ion source used in the focused ion beam processing method may be a gallium metal ion source or a helium ion source.
[0044] To more clearly illustrate the micro-nano scale pattern processing method provided by the embodiments of the present disclosure, the following further describes it by combining the drawings with examples and comparative examples.
[0045] In the comparative example, for the case where there is no polymer coating protection on the metal film layer, the metal Cr film layer on the quartz substrate has a thickness of 40 nm. In the example, for the case where there is polymer coating protection on the metal film layer, the metal Cr film layer on the quartz substrate has a thickness of 40 nm, and the material of the spin-coated polymer coating is PMMA with a thickness of 20 nm.
[0046] Figure 3 Schematically shows a comparison diagram of the effects when there is or is not polymer coating protection on the metal film layer according to an embodiment of the present disclosure.
[0047] As Figure 3 shown, Figure 3 in a and c are the original patterns without and with polymer coating protection respectively, and the surface roughness Ra is less than 3 nm. For the metal film layer in a large area, comparing the metal film layers with and without polymer coating protection, within a region of 1.2 μm, using an ion beam current of 0.7 pA for focusing, focus for 110 s (as Figure 3 in b) and 120 s (as Figure 3 in d) respectively. Using image processing software to characterize the roughness of the film layer after focusing, it can be seen that the film layer with polymer coating protection (as Figure 3 in d) has less loss in some regions, and the surface roughness Ra is 68 nm. While the region diagram without polymer coating protection (as Figure 3 in b) is rougher, and the surface roughness is Ra = 104 nm.
[0048] Figure 4 Schematically shows a comparison diagram of the effect of the polymer coating on reducing the redeposition effect according to an embodiment of the present disclosure.
[0049] For micro-nano scale grating patterns, during focused ion beam processing, the redeposited metal atoms are likely to land on the grating patterns (as Figure 4 in a), which affects the processing quality of the patterns, and the measured value of the line edge roughness of the grating pattern is 5.9 nm. Among them, Figure 4 in b is the pattern after polymer coating protection and removing the polymer coating, and the measured value of the line edge roughness of the grating pattern is 2.9 nm. The results show that the polymer coating has a certain protection effect on the area beside the grating lines.
[0050] Figure 5 Schematically shows the morphology diagram of the film layer around the pattern with or without polymer coating protection according to an embodiment of the present disclosure.
[0051] For the film layer situation around the overall grating, during or after focused ion beam processing, it is inevitable to cause focused damage to the surrounding area, as Figure 5As shown in a, the film layer around the grating pattern is damaged and uneven, and the surface roughness Ra is 84 nm. The pattern after being protected by the polymer coating is as shown in Figure 5 b, the film layer near the micro-nano scale pattern is relatively flat and uniform, and the surface roughness Ra is 5 nm.
[0052] Thus, combining Figure 3 and Figure 5 it can be seen that: the polymer coating can protect the bottom metal film layer and avoid unnecessary damage to the film layer in the peripheral area of the processed pattern. This method is effective for both large-area film layers and the film layer around the pattern.
[0053] Combined with Figure 4 it can be seen that the redeposited metal atoms are deposited on the polymer coating, and there are fewer redeposited metal atoms on the pattern after removing the polymer coating.
[0054] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present disclosure. Although the embodiments are described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present disclosure.
Claims
1. A method for processing micro-nano scale patterns, characterized in that, Including: Forming a metal film layer on the substrate surface; Forming a polymer coating on the surface of the metal film layer, the polymer coating being used to protect the metal film layer during processing; Performing micro-nano scale patterning on the metal film layer with a polymer coating formed on its surface by a focused ion beam processing method, removing the polymer coating after processing is completed, and forming a micro-nano scale pattern on the metal film layer.
2. The method according to claim 1, wherein The material of the polymer coating is a material that does not react with the metal and can be removed after processing is completed.
3. The method according to claim 2, characterized in that The material of the polymer coating includes one of photoresist, silica gel, spin-on glass, epoxy resin, polyurethane, graphene.
4. The method according to any one of claims 1 to 3, characterized in that, The thickness of the polymer coating is 20 nm to 200 nm.
5. The method according to claim 1, characterized in that, The material of the metal film layer includes one of chromium, gold, platinum, silver, tantalum, indium, molybdenum, aluminum.
6. The method according to claim 1 or 5, characterized in that, The thickness of the metal film layer is 40 nm to 10 μm.
7. The method according to claim 1, characterized in that, The ion source used in the focused ion beam processing method is a gallium metal ion source or a helium ion source.
8. The method according to claim 1, characterized in that The material of the substrate includes silicon or quartz glass.
9. The method according to claim 1, wherein The line width of the micro-nano scale pattern is 20 nm to 40 nm.