A multilayer film superlens and surface plasmon lithography method
By designing a multilayer superlens and using highly stable metallic materials, the reliability problem of integrated circuits caused by silver diffusion was solved, achieving high-resolution pattern imaging and process integration, and promoting the application of surface plasmon lithography technology in integrated circuits.
Patent Information
- Application Number
- CN202510190178.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2026-08-25
AI Technical Summary
The silver material used in existing surface plasmon lithography technology is unstable and prone to diffusion, leading to reliability issues in integrated circuits and making it difficult to integrate with large-scale integrated circuit processes.
A multilayer superlens is employed, comprising a substrate, a mask absorption layer, a filling layer, and first and second metal-dielectric composite thin films. Highly stable metal materials such as titanium, tantalum, titanium nitride, or copper are used, and pattern transfer is achieved through surface plasma lithography to avoid metal diffusion contamination of the integrated circuit.
It achieves high-resolution pattern imaging, avoids metal diffusion contamination of integrated circuits, and promotes the integration of surface plasmon lithography technology with large-scale integrated circuit processes.
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Figure CN122632369A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a multilayer superlens and 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 of objects with feature sizes much smaller than the wavelength order of 1000 nm. However, because silver, the main metal material used in SPL, is chemically unstable, it easily diffuses and causes contamination during the lithography process, negatively impacting the reliability of integrated circuits.
[0004] Therefore, how to combine surface plasmon lithography technology with large-scale integrated circuit processes has become a problem that needs to be solved. Summary of the Invention
[0005] To address the aforementioned issues, this application provides a multilayer superlens and a surface plasma lithography method, which can combine surface plasma lithography technology with large-scale integrated circuit processes.
[0006] The embodiments of this application disclose the following technical solutions:
[0007] In a first aspect, embodiments of this application provide a multilayer superlens, the multilayer superlens comprising: a substrate, a mask absorption layer, a filling layer, a first metal-dielectric composite film, and a second metal-dielectric composite film;
[0008] The substrate, mask absorption layer and filler layer, first metal-dielectric composite film and second metal-dielectric composite film are stacked in sequence; the mask absorption layer and the filler layer are in contact with the dielectric side of the first metal-dielectric composite film;
[0009] The metal layers in the first and second metal-dielectric composite films are made of the same metal; the metal layer is made of any one of titanium, tantalum, titanium nitride, and copper.
[0010] The projection of the mask absorption layer onto the substrate surface is a periodically arranged pattern.
[0011] Optionally, the projection of the mask absorption layer onto the substrate surface is a periodically arranged line.
[0012] Optionally, the periodically arranged pattern has an arrangement period of 260 nm.
[0013] Optionally, in both the first metal-dielectric composite film and the second metal-dielectric composite film, the dielectric layer material is titanium dioxide.
[0014] Optionally, the mask absorption layer and the filling layer have the same thickness.
[0015] Optionally, the thickness of the mask absorption layer is 40 nm.
[0016] Optionally, the mask absorption layer is a chromium layer.
[0017] Optionally, in the first metal-dielectric composite film and the second metal-dielectric composite film, the thickness of the metal layer is 10 nm and the thickness of the dielectric layer is 20 nm.
[0018] Optionally, the sidewall angle of the mask absorption layer is 0°.
[0019] Secondly, embodiments of this application provide a surface plasma lithography method, the method comprising:
[0020] Provides TM polarized light with a wavelength of 365nm as incident light;
[0021] Based on the incident light, the multilayer superlens described in any embodiment of the first aspect is incident from the substrate side, and the pattern in the multilayer superlens is transferred to the surface of the structure to be lithographically etched; 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 thin film in the multilayer superlens described in any embodiment of the first aspect; the material of the metal reflective layer is any one of titanium, tantalum, titanium nitride and copper.
[0022] Compared with the prior art, this application has the following beneficial effects:
[0023] This application provides a multilayer superlens, comprising: a substrate, a mask absorption layer, a filling layer, a first metal-dielectric composite film, and a second metal-dielectric composite film; the substrate, the mask absorption layer, the filling layer, the first metal-dielectric composite film, and the second metal-dielectric composite film are stacked sequentially; the mask absorption layer and the filling layer are in contact with the dielectric side of the first metal-dielectric composite film; the metal layers in the first and second metal-dielectric composite films are made of the same metal; the metal layer material is any one of titanium, tantalum, titanium nitride, and copper; the projection of the mask absorption layer onto the surface of the substrate is a periodically arranged pattern. Therefore, a multilayer superlens using a highly stable metallic material is provided. Surface plasmon lithography is performed based on the multilayer superlens provided in this application embodiment. The hyperbolic metamaterial composed of a metal-dielectric composite thin film excites surface plasmons, and near-field lithography imaging based on the surface plasmons of the optical frequency negative refractive material can avoid contamination of the integrated circuit structure to be etched due to metal diffusion in the multilayer superlens. This is friendly to integrated circuit processes. Furthermore, based on the multilayer lens provided in this application embodiment, surface plasmon lithography technology can be applied in integrated circuit manufacturing processes, realizing the combination of surface plasmon lithography technology and large-scale integrated circuit processes. Attached Figure Description
[0024] 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.
[0025] Figure 1 A schematic diagram of a multilayer film superlens structure provided in an embodiment of this application;
[0026] Figure 2 A schematic diagram of the imaging results of a silver-based multilayer superlens provided in an embodiment of this application;
[0027] Figure 3 A schematic diagram of the imaging results of a titanium-based multilayer superlens provided in an embodiment of this application;
[0028] Figure 4 A schematic diagram of the imaging results of a tantalum-based multilayer superlens provided in an embodiment of this application;
[0029] Figure 5 A schematic diagram of the imaging results of a multilayer superlens based on titanium nitride provided in an embodiment of this application;
[0030] Figure 6A schematic diagram of the imaging results of a copper-based multilayer superlens provided in an embodiment of this application;
[0031] Figure 7 A flowchart of a surface plasma lithography method provided in this application embodiment;
[0032] Figure 8 This is a schematic diagram of a structure to be lithographically etched, provided as an embodiment of this application. Detailed Implementation
[0033] The multilayer superlens and surface plasma lithography method 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 multilayer superlens and surface plasma lithography method provided in this application.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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 mask absorption layer 102 and the filler layer 103 have the same thickness. The filler layer 103 is used to fill the gaps in the pattern formed by the mask absorption layer 102, reducing optical interference caused by uneven surfaces.
[0041] 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; the metal layer material is any one of titanium, tantalum, titanium nitride, and copper.
[0042] The projection of the mask absorption layer 102 onto the surface of the substrate 101 is a periodically arranged pattern. The material of the mask absorption layer 102 can be chromium (Cr).
[0043] 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.
[0044] In this embodiment, a first metal-dielectric composite film 104 and a second metal-dielectric composite film 105 are stacked. The metal layer material is any one of titanium, tantalum, titanium nitride, and copper, which exhibit a negative effective dielectric constant (ε<0) in the ultraviolet region. The dielectric layer material can be titanium dioxide (TiO2), which, as a high refractive index medium, has a positive effective dielectric constant (ε>0) in the ultraviolet region. By alternately stacking the metal and dielectric layers, a multilayer structure with an anisotropic dielectric constant is constructed, forming a hyperbolic metamaterial.
[0045] When light shines on 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 light onto very small points to achieve nanometer-level resolution.
[0046] Optionally, the projection of the mask absorption layer 102 onto the surface of the substrate 101 is a periodically arranged line.
[0047] The line width can be 130 nm; the arrangement period is less than but close to the incident light wavelength to induce a diffraction effect. To obtain a pattern with high resolution and contrast through surface plasmon lithography, the arrangement period can be 260 nm when the incident light is TM polarized light with a wavelength of 365 nm.
[0048] Optionally, in both the first metal-dielectric composite film 104 and the second metal-dielectric composite film 105, the dielectric layer material is titanium dioxide.
[0049] Optionally, in the first metal-dielectric composite film 104 and the second metal-dielectric composite film 105, the thickness of the metal layer is 10 nm and the thickness of the dielectric layer is 20 nm.
[0050] Optionally, the mask absorption layer 102 has a thickness of 40 nm and a sidewall angle of 0° to ensure clear definition of the pattern edges and achieve high-precision photolithography.
[0051] Therefore, this application provides a multilayer superlens using a highly stable metallic material. Surface plasmon lithography is performed based on the multilayer superlens provided in this application. The hyperbolic metamaterial composed of a metal-dielectric composite thin film excites surface plasmons, and near-field lithography imaging based on the surface plasmons of the optical frequency negative refractive material can avoid contamination of the integrated circuit structure to be etched due to metal diffusion in the multilayer superlens. This is friendly to integrated circuit processes. Furthermore, based on the multilayer lens provided in this application, surface plasmon lithography technology can be applied in integrated circuit manufacturing processes, realizing the combination of surface plasmon lithography technology and large-scale integrated circuit processes.
[0052] Furthermore, in the multilayer superlens structure provided in this application embodiment, titanium, tantalum, copper, or titanium nitride are selected as the material of the metal layer in the metal-dielectric composite film. Compared with selecting silver as the material of the metal layer in the metal-dielectric composite film, the imaging contrast of surface plasmon lithography can also be improved.
[0053] The FDTD solutions software can be used to model and simulate the optical behavior of light in the multilayer superlens provided in this application, and calculate the electric field intensity of the spatial image at the middle position of the mask layer in the structure to be lithographicated after surface plasmon lithography, in order to evaluate the imaging effect. In the embodiments of this application, all components in the y-direction are considered to be infinite to simplify the calculation model and ignore the finite size effect in the y-direction.
[0054] See Figure 2The figure is a schematic diagram of the imaging result of a silver-based multilayer superlens provided in the embodiment of this application, which can be simulated by the FDTD (Finite-Difference Time-Domain) method.
[0055] Figure 2 In Figure (a), the spatial image in the mask layer is the imaging curve in the xz direction. The horizontal axis represents the position and the vertical axis represents the light intensity. The spatial image curve in the xz direction is used to describe the change of light intensity along the transverse direction (x direction) and perpendicular to the surface of the substrate 101 (z direction). This curve provides information about the location of the focal point, the intensity distribution, and the imaging resolution.
[0056] Figure 2 (b) is a two-dimensional thermal image showing the intensity distribution of the image on the xy plane. Both the horizontal and vertical axes represent positions. The observation position of the spatial image of the mask layer is at y = 25nm on the y-axis. The image shows the intensity distribution at different positions through color changes. See the color scale on the right. Blue represents low intensity and red represents high intensity.
[0057] Imaging contrast C = (I max -I min ) / I avg I max I represents the average light intensity in the region of maximum light intensity. min I represents the average light intensity in the region of minimum light intensity. avg This represents the average light intensity across the entire image area.
[0058] The calculation formula based on imaging contrast and Figure 2 The imaging results of the silver-based multilayer superlens provided in the paper can be used with the software FDTD solutions to calculate the imaging contrast C of the multilayer superlens when silver is selected as the material of the metal layer in the metal-dielectric composite thin film. Ag =0.85.
[0059] See Figure 3 The figure is a schematic diagram of the imaging result of a titanium-based multilayer superlens provided in the embodiment of this application, which can be simulated by the FDTD (Finite-Difference Time-Domain) method.
[0060] Figure 3 In the middle (a), the spatial image in the mask layer is the imaging curve in the xz direction. The horizontal axis represents the position and the vertical axis represents the light intensity. Figure 3(b) is a two-dimensional thermal image showing the intensity distribution of the image on the xy plane. Both the horizontal and vertical axes represent positions. The observation position of the spatial image of the mask layer is at y = 25nm on the y-axis. The image shows the intensity distribution at different positions through color changes. See the color scale on the right. Blue represents low intensity and red represents high intensity.
[0061] The calculation formula based on imaging contrast and Figure 3 The imaging results of the titanium-based multilayer superlens provided in the paper can be used with the software FDTD solutions to calculate the imaging contrast C of the multilayer superlens when titanium is selected as the material of the metal layer in the metal-dielectric composite thin film. Ti =0.96.
[0062] See Figure 4 The figure is a schematic diagram of the imaging result of a tantalum-based multilayer superlens provided in the embodiment of this application, which can be simulated by the FDTD (Finite-Difference Time-Domain) method.
[0063] Figure 4 In the middle (a), the spatial image in the mask layer is the imaging curve in the xz direction. The horizontal axis represents the position and the vertical axis represents the light intensity. Figure 4 (b) is a two-dimensional thermal image showing the intensity distribution of the image on the xy plane. Both the horizontal and vertical axes represent positions. The observation position of the spatial image of the mask layer is at y = 25nm on the y-axis. The image shows the intensity distribution at different positions through color changes. See the color scale on the right. Blue represents low intensity and red represents high intensity.
[0064] The calculation formula based on imaging contrast and Figure 4 The imaging results of the tantalum-based multilayer superlens provided in the paper can be used with the software FDTD solutions to calculate the imaging contrast C of the multilayer superlens when tantalum is selected as the material of the metal layer in the metal-dielectric composite thin film. Ta =0.99.
[0065] See Figure 5 The figure is a schematic diagram of the imaging result of a multilayer superlens based on titanium nitride provided in the embodiment of this application, which can be simulated by the FDTD (Finite-Difference Time-Domain) method.
[0066] Figure 5 In the middle (a), the spatial image in the mask layer is the imaging curve in the xz direction. The horizontal axis represents the position and the vertical axis represents the light intensity. Figure 5(b) is a two-dimensional thermal image showing the intensity distribution of the image on the xy plane. Both the horizontal and vertical axes represent positions. The observation position of the spatial image of the mask layer is at y = 25nm on the y-axis. The image shows the intensity distribution at different positions through color changes. See the color scale on the right. Blue represents low intensity and red represents high intensity.
[0067] The calculation formula based on imaging contrast and Figure 5 The imaging results of the multilayer superlens based on titanium nitride provided in the paper can be used to calculate the imaging contrast C of the multilayer superlens when titanium nitride is selected as the material of the metal layer in the metal-dielectric composite thin film using the software FDTD solutions. TiN =0.95.
[0068] See Figure 6 The figure is a schematic diagram of the imaging result of a copper-based multilayer superlens provided in the embodiment of this application, which can be simulated by the FDTD (Finite-Difference Time-Domain) method.
[0069] Figure 6 In the middle (a), the spatial image in the mask layer is the imaging curve in the xz direction. The horizontal axis represents the position and the vertical axis represents the light intensity. Figure 6 (b) is a two-dimensional thermal image showing the intensity distribution of the image on the xy plane. Both the horizontal and vertical axes represent positions. The observation position of the spatial image of the mask layer is at y = 25nm on the y-axis. The image shows the intensity distribution at different positions through color changes. See the color scale on the right. Blue represents low intensity and red represents high intensity.
[0070] The calculation formula based on imaging contrast and Figure 6 The imaging results of the copper-based multilayer superlens provided in the paper can be used with the software FDTD solutions to calculate the imaging contrast C of the multilayer superlens when copper is selected as the material of the metal layer in the metal-dielectric composite thin film. Cu =0.96.
[0071] Depend on Figure 2 , Figure 3 , Figure 4 , Figure 5 as well as Figure 6 The provided multilayer superlens imaging results and corresponding imaging contrast show that, compared to choosing silver as the material for the metal layer in a metal-dielectric composite film, using titanium, tantalum, copper, or titanium nitride as the material for the metal layer in a metal-dielectric composite film can significantly improve the imaging contrast of surface plasmon lithography, thereby enhancing the imaging resolution of surface plasmon lithography and helping to promote the integration and development of surface plasmon lithography technology with large-scale integrated circuit processes.
[0072] See Figure 7 The figure is a flowchart of a surface plasma lithography method provided in an embodiment of this application. The method includes:
[0073] S701: Provides TM polarized light with a wavelength of 365nm as incident light.
[0074] Incident light, after passing through a multilayer superlens, excites surface plasmon waves on the surface of a metal-dielectric composite thin film. These surface plasmon waves propagate across the surface of the metal-dielectric composite thin film and are modulated by the multilayer superlens to form specific interference patterns. By adjusting the structural parameters of the multilayer superlens, such as the thickness of the metal and dielectric layers in the metal-dielectric composite thin film, precise control of the interference pattern can be achieved, thereby enabling high-precision imaging using surface plasmon lithography.
[0075] S702: Incident light is incident from the substrate side of the multilayer superlens provided in any of the above embodiments, and a photolithography pattern is formed on the mask layer of the structure to be photolithographically ...
[0076] See Figure 8 The figure is a schematic diagram of a structure to be lithographically etched according to an embodiment of this application.
[0077] The structure to be lithographically etched includes a wafer 801, a metal reflective layer 802, and a mask layer 803 stacked sequentially. The mask layer 803 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.
[0078] The metal reflective layer 802 is made of any one of titanium, tantalum, titanium nitride, and copper, and its thickness can be 40 nm.
[0079] Optionally, the material of the metal reflective layer 802 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.
[0080] Optionally, the mask layer 803 is a photoresist layer with a thickness of 20nm.
[0081] Therefore, in this application embodiment, surface plasma lithography is performed based on the multilayer superlens provided in any of the above embodiments. The surface plasma is excited by the hyperbolic metamaterial composed of metal-dielectric composite thin film, and the surface plasma near-field lithography imaging is based on the optical frequency negative refractive material. This can avoid contamination of the integrated circuit structure to be etched due to metal diffusion in the multilayer superlens, and is friendly to integrated circuit process. It can combine surface plasma lithography technology with large-scale integrated circuit process.
[0082] In addition, embodiments of this application also provide a photolithography apparatus, which includes a memory and a processor.
[0083] Memory is used to store program code and transfer program code to the processor.
[0084] The processor is used to execute the steps of the above-described surface plasmon lithography method according to the program code.
[0085] 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.
[0086] 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 multilayer superlens, characterized in that, The multilayer superlens includes: a substrate, a mask absorption layer, a filling layer, a first metal-dielectric composite film, and a second metal-dielectric composite film; The substrate, mask absorption layer and filler layer, first metal-dielectric composite film and second metal-dielectric composite film are stacked in sequence; the mask absorption layer and the filler layer are in contact with the dielectric side of the first metal-dielectric composite film; The metal layers in the first and second metal-dielectric composite films are made of the same metal; the metal layer is made of any one of titanium, tantalum, titanium nitride, and copper. The projection of the mask absorption layer onto the substrate surface is a periodically arranged pattern.
2. The multilayer superlens according to claim 1, characterized in that, The projection of the mask absorption layer onto the substrate surface is a periodically arranged line.
3. The multilayer superlens according to claim 1, characterized in that, The periodically arranged pattern has a period of 260 nm.
4. The multilayer superlens according to claim 1, characterized in that, In both the first metal-dielectric composite film and the second metal-dielectric composite film, the dielectric layer material is titanium dioxide.
5. The multilayer superlens according to claim 1, characterized in that, The mask absorption layer and the filling layer have the same thickness.
6. The multilayer superlens according to claim 1, characterized in that, The thickness of the mask absorption layer is 40 nm.
7. The multilayer superlens according to claim 1, characterized in that, The mask absorption layer is a chromium layer.
8. The multilayer superlens according to claim 1, characterized in that, In the first metal-dielectric composite film and the second metal-dielectric composite film, the thickness of the metal layer is 10 nm and the thickness of the dielectric layer is 20 nm.
9. The multilayer superlens according to claim 1, characterized in that, The sidewall angle of the mask absorption layer is 0°.
10. A surface plasma lithography method, characterized in that, The method includes: Provides TM polarized light with a wavelength of 365nm as incident light; The incident light is incident orthogonally from the substrate side of the multilayer superlens according to any one of claims 1 to 9, and a photolithographic pattern is formed on the mask layer of the structure to be photolithographically ...