A surface plasmon lithography method
Patent Information
- Application Number
- CN202510190177.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2026-08-21
AI Technical Summary
在集成电路工艺中，采用表面等离子体光刻技术形成特定的图形，需要预先进行复杂的计算模拟和实验验证，设计相应的多层膜超透镜，多层膜超透镜的设计成本较高
[0024]本申请实施例中，首先，基于目标成像图形，确定目标图案的内半径尺寸和排列方式；所述目标图案为多层膜超透镜中掩膜吸收层在基底表面投影所形成的周期性排列的环形；而后，提供波长为365nm的TM偏振光作为入射光；最后，入射光从具有目标图案的目标多层膜超透镜的基底侧正入射，在待光刻结构的掩膜层上形成目标成像图形；所述多层膜超透镜包括依次堆叠的基底、掩膜吸收层和填充层、第一金属-介质复合薄膜以及第二金属-介质复合薄膜；所述待光刻结构包括依次堆叠的晶圆、金属反射层以及掩膜层；所述掩膜层位于靠近所述目标多层膜超透镜中的第二金属-介质复合薄膜的一侧。由此，仅需改变目标图案的内半径尺寸和排列方式，即改变多层膜超透镜中掩膜吸收层在基底表面投影所形成的环形的内半径尺寸和排列方式，即可对所形成的成像图形进行调控，多层膜超透镜中掩膜吸收层的设计成本较低，从而能够低成本地利用多层膜超透镜在集成电路工艺中实现特定图形成像。
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Figure CN122613655A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a surface plasma lithography method. Background Technology
[0002] As integrated circuit process nodes shrink, the ability to image fine structures in large-scale integrated circuit processes is attracting increasing attention.
[0003] Surface plasmon lithography (SPL) is a photolithography method that uses surface plasmon polaritons (SPPs) for high-resolution patterning. It utilizes specially designed metal thin films to couple and transmit evanescent waves, enabling the imaging of fine structures in objects with feature sizes much smaller than the wavelength order of 160 nm. In integrated circuit manufacturing, forming specific patterns using SPL requires complex pre-calculation simulations and experimental verification, as well as the design of corresponding multilayer superlenses. The design cost of multilayer superlenses is relatively high.
[0004] Therefore, how to achieve specific pattern imaging in integrated circuit processes using multilayer superlenses at low cost has become a problem that needs to be solved. Summary of the Invention
[0005] To address the aforementioned issues, this application provides a surface plasmonic lithography method that can achieve specific pattern imaging in integrated circuit processes using multilayer superlenses at low cost.
[0006] The embodiments of this application disclose the following technical solutions:
[0007] This application provides a surface plasma lithography method, the method comprising:
[0008] Based on the target imaging pattern, the inner radius and arrangement of the target pattern are determined; the target pattern is a periodically arranged ring formed by the projection of the mask absorption layer in the multilayer superlens onto the substrate surface;
[0009] Provides TM polarized light with a wavelength of 365nm as incident light;
[0010] The incident light is incident orthogonally from the substrate side of the target multilayer superlens having the target pattern, forming the target imaging pattern on the mask layer of the structure to be lithographically etched; the multilayer superlens includes a substrate, a mask absorption layer and a filling layer, a first metal-dielectric composite film and a second metal-dielectric composite film stacked sequentially; the structure to be lithographically etched includes a wafer, a metal reflective layer and a mask layer stacked sequentially; the mask layer is located on the side close to the second metal-dielectric composite film in the target multilayer superlens.
[0011] Optionally, determining the inner radius and arrangement of the target pattern based on the target imaging pattern includes:
[0012] When the shape of the target image is a line, the inner radius of the target pattern is determined as the first dimension, and the arrangement is close arrangement; the first dimension is greater than 1 / 2 of the outer radius of the target pattern.
[0013] Optionally, determining the inner radius and arrangement of the target pattern based on the target imaging pattern includes:
[0014] When the target image is circular, the inner radius of the target pattern is determined as the first dimension, and the pattern is arranged in an alternating pattern with the outer diameter of the target pattern as the period; the first dimension is greater than 1 / 2 of the outer radius of the target pattern.
[0015] Optionally, the mask layer of the structure to be photolithographically etched is a negative photoresist layer.
[0016] Optionally, the outer radius of the target pattern is 65 nm, and the first dimension of the inner radius of the target pattern is 50 nm.
[0017] Optionally, determining the inner radius and arrangement of the target pattern based on the target imaging pattern includes:
[0018] When the target image is square, the inner radius of the target pattern is determined as the second dimension, and the pattern is arranged in an alternating pattern with the outer diameter of the target pattern as the period; the second dimension is less than 1 / 2 of the outer radius of the target pattern.
[0019] Optionally, the mask layer of the structure to be lithographically modeled is a positive photoresist layer.
[0020] Optionally, the outer radius of the target pattern is 65 nm, and the second dimension of the inner radius of the target pattern is 30 nm.
[0021] Optionally, the mask absorption layer in the target multilayer superlens is a chromium layer.
[0022] Optionally, the mask absorption layer and the filling layer in the target multilayer superlens have the same thickness.
[0023] Compared with the prior art, this application has the following beneficial effects:
[0024] In this embodiment, firstly, based on the target imaging pattern, the inner radius and arrangement of the target pattern are determined; the target pattern is a periodically arranged ring formed by the projection of the mask absorption layer in the multilayer superlens onto the substrate surface; then, TM polarized light with a wavelength of 365nm is provided as the incident light; finally, the incident light is incident orthogonally from the substrate side of the target multilayer superlens with the target pattern, forming the target imaging pattern on the mask layer of the structure to be lithographically etched; the multilayer superlens includes a substrate, a mask absorption layer and a filling layer, a first metal-dielectric composite film and a second metal-dielectric composite film stacked sequentially; the structure to be lithographically etched includes a wafer, a metal reflective layer and a mask layer stacked sequentially; the mask layer is located on the side close to the second metal-dielectric composite film in the target multilayer superlens. Therefore, by simply changing the inner radius and arrangement of the target pattern, that is, by changing the inner radius and arrangement of the ring formed by the projection of the mask absorption layer on the substrate surface in the multilayer superlens, the resulting imaging pattern can be controlled. The design cost of the mask absorption layer in the multilayer superlens is low, thus enabling the use of multilayer superlenses to achieve specific pattern imaging in integrated circuit processes at low cost. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram of a multilayer superlens structure provided in an embodiment of this application;
[0027] Figure 2 This is a schematic diagram of a structure to be photolithographically etched, provided in an embodiment of this application.
[0028] Figure 3 A flowchart of a surface plasma lithography method provided in this application embodiment;
[0029] Figure 4 A schematic diagram of a target pattern provided in an embodiment of this application;
[0030] Figure 5 This application provides a two-dimensional thermal image of the light intensity distribution on the xy plane of a film layer.
[0031] Figure 6 This is another schematic diagram of a target pattern provided in an embodiment of this application;
[0032] Figure 7This application provides another two-dimensional thermal image of the light intensity distribution on the xy plane of the film layer.
[0033] Figure 8 This is another schematic diagram of a target pattern provided in the embodiments of this application;
[0034] Figure 9 This application provides another two-dimensional thermal image of the light intensity distribution on the xy plane of the film layer. Detailed Implementation
[0035] The surface plasmon lithography method and multilayer superlens provided in this application can be used in the semiconductor manufacturing field. The above is only an example and does not limit the application field of the surface plasmon lithography method and multilayer superlens provided in this application.
[0036] The terms "first," "second," "third," and "fourth," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.
[0037] In the embodiments of this application, the terms "as an example" or "for example" are used to indicate that they are examples, illustrations, or explanations. Any embodiment or design that is described as "as an example" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of terms such as "as an example" or "for example" is intended to present the relevant concepts in a specific manner.
[0038] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.
[0039] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.
[0040] A multilayer metasurface superlens is an optical element designed based on the concept of metamaterials. It utilizes nanoscale structures to manipulate light waves, enabling precise control over properties such as the phase, amplitude, and polarization of light. Multilayer metasurface superlenses can surpass the traditional diffraction limit, providing higher resolution than conventional optical lenses.
[0041] See Figure 1The figure is a schematic diagram of a multilayer superlens structure provided in an embodiment of this application. The multilayer superlens includes: a substrate 101, a mask absorption layer 102, a filling layer 103, a first metal-dielectric composite film 104, and a second metal-dielectric composite film 105.
[0042] A substrate 101, a mask absorption layer 102, a filler layer 103, a first metal-dielectric composite film 104, and a second metal-dielectric composite film 105 are stacked sequentially; the mask absorption layer 102 and the filler layer 103 are in contact with the dielectric side of the first metal-dielectric composite film 104. The substrate 101 can be made of silicon dioxide (SiO2).
[0043] The mask absorption layer 102 and the filling layer 103 have the same thickness. The filling layer 103 is used to fill the gaps in the pattern formed by the mask absorption layer 102 and reduce optical interference caused by uneven surfaces.
[0044] The metal layers in the first metal-dielectric composite film 104 and the second metal-dielectric composite film 105 are made of the same metal, such as silver (Ag); the dielectric layers are also made of the same material, such as titanium dioxide (TiO2). That is, both the first metal-dielectric composite film 104 and the second metal-dielectric composite film 105 are Ag / TiO2 composite films, wherein the thickness of each metal layer can be 10 nm, and the thickness of each dielectric layer can be 20 nm.
[0045] The projection of the mask absorption layer 102 onto the surface of the substrate 101 is a periodically arranged ring.
[0046] Optionally, the mask absorption layer 102 can be made of chromium (Cr); the thickness of the mask absorption layer 102 can be 40 nm, with 0° sidewall corners to ensure clear definition of the pattern edges and facilitate high-precision photolithography. The filling layer 103 is made of TiO2, which matches the real part of the dielectric constant of Ag; the thickness of the filling layer 103 is also 40 nm.
[0047] Hyperbolic metamaterials (HMMs) are artificially designed composite structures with a positive dielectric constant in one direction and a negative dielectric constant in another, resulting in a hyperbolic isofrequency profile. The unique dielectric properties of hyperbolic metamaterials enable them to support anomalous electromagnetic modes at subwavelength scales, such as extremely high effective refractive indices or negative refractive phenomena.
[0048] In this embodiment, a first metal-dielectric composite film 104 and a second metal-dielectric composite film 105 are stacked. By alternately stacking metal layers and dielectric layers, a multilayer structure with an anisotropic dielectric constant is constructed, forming a hyperbolic metamaterial.
[0049] When incident light irradiates HMMs composed of a first metal-dielectric composite film 104 and a second metal-dielectric composite film 105, surface plasmons can be excited. These surface plasmons can propagate inside the material and undergo negative refraction at specific locations, simulating the effect of negative refractive index materials, compensating for the loss of evanescent waves and reconstructing high-resolution images, thereby focusing the light to a very small point to achieve nanometer-level resolution.
[0050] See Figure 2 The figure is a schematic diagram of a structure to be lithographically etched according to an embodiment of this application.
[0051] The structure to be lithographically etched includes at least a wafer 201, a metal reflective layer 202, and a mask layer 203 stacked sequentially. The mask layer 203 is located on one side close to the second metal-dielectric composite thin film 105 in the multilayer superlens provided in any of the above embodiments.
[0052] Optionally, the material of the metal reflective layer 202 is the same as the material of the metal layer in the first metal-dielectric composite film 104 and the second metal-dielectric composite film 105, for example, it can be silver; the thickness can be 40 nm.
[0053] Optionally, the mask layer 203 is a photoresist layer with a thickness of 20 nm. Positive or negative photoresist can be selected based on the target imaging pattern and the corresponding target multilayer superlens.
[0054] As an example, a metal reflective layer 202 can be deposited on the surface of wafer 201 first, and then photoresist can be coated on the surface of the metal reflective layer 202 to obtain a mask layer 203, forming the structure to be lithographically patterned. A multilayer superlens is placed above the mask layer 203, and the illumination angle and intensity of the incident light are adjusted so that the incident light can illuminate the multilayer superlens and excite surface plasmons. The surface plasmons propagate inside the multilayer superlens and undergo negative refraction at a specific location, focusing the light onto a specific location on the mask layer, thereby forming a high-resolution target image pattern on the mask layer of the structure to be lithographically patterned.
[0055] See Figure 3 The figure is a flowchart of a surface plasma lithography method provided in an embodiment of this application. The method includes:
[0056] S301: Based on the target imaging pattern, determine the inner radius size and arrangement of the target pattern.
[0057] The target pattern is a periodically arranged ring formed by the projection of the mask absorption layer 102 in the multilayer superlens onto the surface of the substrate 101.
[0058] Using the software tool FDTD solutions, we can construct models and simulate the optical behavior of light within the multilayer superlens provided in any embodiment of this application. Through this simulation, the electric field intensity of the spatial image at the center of the mask layer in the structure to be lithographicated can be calculated after surface plasmon lithography, thereby evaluating the image quality. In the embodiments of this application, to simplify the calculation model and ignore the finite size effect in the y-direction, it can be assumed that all components in the y-direction are infinitely large.
[0059] By changing the inner radius and arrangement of the ring (i.e., the target pattern) formed by the projection of the mask absorption layer 102 onto the surface of the substrate 101 in a multilayer superlens, target imaging patterns of various basic shapes commonly used in integrated circuit processes can be obtained. Software tools can be used to adjust the inner radius and arrangement of the target pattern, resulting in imaging effects corresponding to different inner radius and arrangement patterns. Therefore, software tools can establish a correspondence between the imaging effect and the inner radius and arrangement of the target pattern. Based on this established correspondence, a multilayer superlens with a target pattern having a corresponding inner radius and arrangement can be selected to facilitate the formation of the target imaging pattern on the mask layer of the structure to be lithographically modeled.
[0060] As an example, when the shape of the target image is a linear one-dimensional line, the inner radius r of the target pattern can be determined as the first dimension, and the arrangement is close-packed, such as... Figure 4 As shown; where the first dimension is greater than 1 / 2 of the outer radius of the target pattern. In this case, the mask layer in the corresponding structure to be lithographically modeled can be a negative photoresist.
[0061] As another example, when the shape of the target image is a circle (including an ellipse) in a linear two-dimensional hole structure, the inner radius r of the target pattern can be determined as the first dimension, and the arrangement can be staggered with the outer diameter of the target pattern as the period, such as... Figure 6 As shown; where the first dimension is greater than 1 / 2 of the outer radius of the target pattern. In this case, the mask layer in the corresponding structure to be lithographically modeled can be a negative photoresist.
[0062] Optionally, the outer radius R of the target pattern is 65 nm, and the first dimension r of the inner radius of the target pattern is 50 nm.
[0063] As another example, when the target image is a square in a linear two-dimensional hole structure, the inner radius *r* of the target pattern is determined as the second dimension, and the arrangement is an alternating arrangement with the outer diameter of the target pattern as the period, such as... Figure 8As shown; where the second dimension is less than 1 / 2 of the outer radius of the target pattern. In this case, the mask layer in the corresponding structure to be lithographically modeled can be a positive photoresist.
[0064] Optionally, the outer radius R of the target pattern is 65 nm, and the second dimension r of the inner radius of the target pattern is 30 nm.
[0065] S302: Provides TM polarized light with a wavelength of 365nm as incident light.
[0066] On the one hand, the electric field of the TM (Transverse Magnetic) mode has a component parallel to the metal surface, which is precisely the condition required to excite surface plasmon polaritons (SPPs). Therefore, at the metal-dielectric interface, TM-polarized light more easily excites SPPs, improving the excitation efficiency, enhancing associated nonlinear optical effects, and achieving higher resolution.
[0067] On the other hand, according to the Rayleigh criterion, the minimum feature size in photolithography is proportional to the wavelength of the light source. Therefore, providing incident light with a wavelength of 365nm can further improve the resolution of photolithography and achieve finer patterning. In addition, 365nm ultraviolet light is a commonly used wavelength in photolithography processes, and the related optical components and technologies are mature and applicable to a variety of photoresists. Using incident light with a wavelength of 365nm also has certain technical and cost advantages.
[0068] S303: Incident light is incident from the substrate side of the target multilayer superlens with the target pattern, forming the target imaging pattern on the mask layer of the structure to be lithographically etched.
[0069] Incident light passes through the target multilayer superlens, exciting surface plasmon waves on the surface of the metal-dielectric composite thin film within the target multilayer superlens. These surface plasmon waves propagate on the surface of the metal-dielectric composite thin film and are modulated by the target multilayer superlens to form a target imaging pattern. Specifically, the mask layer 203 in the structure to be lithographically etched is close to the second metal-dielectric composite thin film 105 in the target multilayer superlens.
[0070] See Figure 5 , Figure 7 as well as Figure 9 , Figure 5 , Figure 7 as well as Figure 9 To display a two-dimensional thermal image of the light intensity distribution on the xy plane of the mask layer, both the horizontal and vertical axes represent positions. The image uses color changes to show the light intensity distribution at different positions in the mask layer. See the color scale on the right. Blue represents low light intensity, and red represents high light intensity.
[0071] As an example, in a target multilayer superlens, where the inner radius of the target pattern is a first dimension and the pattern is closely packed, the target imaging pattern formed on the mask layer of the structure to be lithographically modeled is as follows: Figure 5 As shown, the target image obtained after development is a line.
[0072] As another example, in a target multilayer superlens, where the inner radius of the target pattern is the first dimension and the pattern is arranged in an alternating pattern with the outer diameter of the target pattern as the period, the target imaging pattern formed on the mask layer of the structure to be lithographically modeled is as follows: Figure 7 As shown, a negative photoresist layer is selected for the mask layer corresponding to the structure to be lithographically modeled, and the target image obtained after development is circular.
[0073] As another example, in a target multilayer superlens, where the inner radius of the target pattern is the second dimension and the pattern is arranged in an alternating pattern with the outer diameter of the target pattern as the period, the target imaging pattern formed on the mask layer of the structure to be lithographically modeled is as follows: Figure 9 As shown, a positive photoresist layer is selected as the mask layer corresponding to the structure to be lithographically modeled, and the target image obtained after development is square.
[0074] In this embodiment, firstly, based on the target imaging pattern, the inner radius size and arrangement of the target pattern are determined; then, TM polarized light with a wavelength of 365nm is provided as the incident light; finally, the incident light is incident orthogonally from the substrate side of the target multilayer superlens with the target pattern, forming the target imaging pattern on the mask layer of the structure to be lithographically modeled. Therefore, by simply changing the inner radius size and arrangement of the target pattern, i.e., changing the inner radius size and arrangement of the ring formed by the projection of the mask absorption layer onto the substrate surface in the multilayer superlens, the formed imaging pattern can be controlled. The design cost of the mask absorption layer in the multilayer superlens is low, thus enabling the low-cost implementation of specific pattern imaging in integrated circuit processes using multilayer superlenses.
[0075] In addition, embodiments of this application also provide a photolithography apparatus, which includes a memory and a processor.
[0076] Memory is used to store program code and transfer program code to the processor.
[0077] The processor is used to execute the steps of the above-described surface plasmon lithography method according to the program code.
[0078] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate. The components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.
[0079] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A surface plasma lithography method, characterized in that, The method includes: Based on the target imaging pattern, the inner radius and arrangement of the target pattern are determined; the target pattern is a periodically arranged ring formed by the projection of the mask absorption layer in the multilayer superlens onto the substrate surface; Provides TM polarized light with a wavelength of 365nm as incident light; The incident light is incident orthogonally from the substrate side of the target multilayer superlens having the target pattern, forming the target imaging pattern on the mask layer of the structure to be lithographically etched; the multilayer superlens includes a substrate, a mask absorption layer and a filling layer, a first metal-dielectric composite film and a second metal-dielectric composite film stacked sequentially; the structure to be lithographically etched includes a wafer, a metal reflective layer and a mask layer stacked sequentially; the mask layer is located on the side close to the second metal-dielectric composite film in the target multilayer superlens.
2. The method according to claim 1, characterized in that, The determination of the inner radius and arrangement of the target pattern based on the target imaging pattern includes: When the shape of the target image is a line, the inner radius of the target pattern is determined as the first dimension, and the arrangement is close arrangement; the first dimension is greater than 1 / 2 of the outer radius of the target pattern.
3. The method according to claim 1, characterized in that, The determination of the inner radius and arrangement of the target pattern based on the target imaging pattern includes: When the target image is circular, the inner radius of the target pattern is determined as the first dimension, and the pattern is arranged in an alternating pattern with the outer diameter of the target pattern as the period; the first dimension is greater than 1 / 2 of the outer radius of the target pattern.
4. The method according to claim 3, characterized in that, The mask layer of the structure to be lithographically modeled is a negative photoresist layer.
5. The method according to claim 2 or 3, characterized in that, The outer radius of the target pattern is 65 nm, and the first dimension of the inner radius of the target pattern is 50 nm.
6. The method according to claim 1, characterized in that, The determination of the inner radius and arrangement of the target pattern based on the target imaging pattern includes: When the target image is square, the inner radius of the target pattern is determined as the second dimension, and the pattern is arranged in an alternating pattern with the outer diameter of the target pattern as the period; the second dimension is less than 1 / 2 of the outer radius of the target pattern.
7. The method according to claim 6, characterized in that, The mask layer of the structure to be lithographically modeled is a positive photoresist layer.
8. The method according to claim 6, characterized in that, The outer radius of the target pattern is 65 nm, and the second dimension of the inner radius of the target pattern is 30 nm.
9. The method according to claim 1, characterized in that, The mask absorption layer in the target multilayer superlens is a chromium layer.
10. The method according to claim 1, characterized in that, The mask absorption layer and the filling layer in the target multilayer superlens are of the same thickness.