Optimization method for mask absorption material based on surface plasma multilayer film structure, and plasmonic superlens

Abstract

Provided in the present invention is an optimization method for a mask absorption material based on a surface plasma multilayer film structure. The method comprises the following steps: S1) constructing a plurality of groups of multilayer film superlens structures having different mask absorption layer parameters; S2) modeling and simulating optical behaviors of light in the multilayer film superlens structures by means of software, so as to obtain the image contrast of a spatial image formed at the middle position of a photoresist covering a substrate layer; and S3) on the basis of the image contrast, determining the mask absorption layer parameters of the multilayer film superlens structures. Compared with the prior art, the present invention optimizes three-dimensional parameters of mask absorption layers on the basis of multilayer film structures, and the results show that the resolution and imaging contrast of the multilayer film structures are significantly improved.

Description

Optimization method of mask absorption material based on surface plasmon multilayer film structure, plasmon super lens

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 25, 2023, with application number 202311797320.X and invention name “Optimization method of mask absorption material based on surface plasma multilayer film structure and plasma superlens”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the field of semiconductor technology, and in particular relates to an optimization method for a mask absorbing material based on a surface plasma multilayer film structure and a plasma super lens. Background Art

[0003] Surface plasmons can utilize specially designed metal films to couple and transmit evanescent waves, enabling imaging of fine structures of objects with characteristic dimensions far smaller than the wavelength. This provides a feasible method for breaking through the optical diffraction limit and manipulating light fields.

[0004] At the beginning of this century, British researcher J.B. Pendry proposed the concept of a "perfect lens" capable of achieving superdiffraction imaging. Due to its negative refractive index, this lens can couple and transmit high-frequency evanescent wave components, thus achieving superdiffraction optical imaging. In recent years, there has been extensive research and progress in superdiffraction imaging, pushing the boundaries of optical technology and improving imaging resolution.

[0005] Extensive research has focused on the lens component of superdiffraction imaging systems, specifically the multilayer films. Improving and optimizing the structural parameters of superdiffraction lenses has resulted in improved imaging resolution and contrast. However, there has been no research on optimizing the mask parameters, which are closely related to the imaging structure.

[0006] Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide an optimization method for mask absorption materials based on surface plasma multilayer film structure and a plasma superlens, through which the lithography resolution and graphic contrast of the plasma superlens can be enhanced.

[0008] The present invention provides a method for optimizing a mask absorbing material based on a surface plasma multilayer film structure, comprising the following steps:

[0009] S1) constructing multiple sets of multilayer film superlens structures with different mask absorption layer parameters; the multilayer film superlens structure includes a multilayer film structure of quartz glass, multiple mask absorption layers, a polymer spacer layer, and a metal-dielectric alternating stack; the multiple mask absorption layers are disposed on the surface of the quartz glass; the polymer spacer layer is disposed between the multiple mask absorption layers and on the surface of the multiple mask absorption layers; the metal-dielectric alternating stacked multilayer film structure is disposed on the surface of the polymer spacer layer;

[0010] S2) simulating the optical behavior of light in the multilayer film superlens structure through software modeling to obtain the image contrast of the aerial image formed at the center position of the photoresist coated on the substrate layer;

[0011] S3) Determine the mask absorption layer parameters of the multilayer film super lens structure according to the image contrast.

[0012] Preferably, the parameters of the mask absorption layer include one or more of the thickness of the mask absorption layer, the material type of the mask absorption layer, and the sidewall angle of the mask absorption layer.

[0013] Preferably, the thickness of the mask absorption layer is 10 to 160 nm; the mask absorption layer includes a MoSi layer and / or a Cr layer, and when the mask absorption layer includes a MoSi layer and a Cr layer, the MoSi layer is in contact with the quartz glass; the side wall angle of the mask absorption layer is 0° to 30°.

[0014] Preferably, the multiple groups of multilayer film superlens structures with different mask absorption layer parameters include multiple groups of multilayer film superlens structures in which the mask absorption layers are Cr layers of different thicknesses and multiple groups of multilayer film superlens structures in which the mask absorption layers are MoSi layers and Cr layers;

[0015] The multiple groups of mask absorption layers are MoSi layers and Cr layers in the multilayer film super lens structure, the thickness of the Cr layers is the same, the thickness of the MoSi layers is different, and the MoSi layers are in contact with the quartz glass.

[0016] Preferably, the multiple groups of multilayer film superlens structures with different mask absorption layer parameters include multiple groups of multilayer film superlens structures with different side wall angles of the mask absorption layer.

[0017] Preferably, the slit width of the mask absorption layer is 140-160 nm; and the period of the mask absorption layer is 280-320 nm.

[0018] Preferably, the thickness of the polymer spacer layer is 100 to 200 nm;

[0019] The thickness of the metal-medium alternately stacked multilayer film structure is 250-350 nm.

[0020] Preferably, the polymer spacer layer is a PMMA layer;

[0021] The metal-medium alternately stacked multilayer film structure is formed by alternately stacking silver layers and titanium dioxide layers, and the titanium dioxide layer is adjacent to the high molecular polymer spacer layer.

[0022] Preferably, in step S2), when the optical behavior of light in the multilayer film superlens structure is simulated by software modeling, the incident angle of the initial incident light source is 0° to 20°;

[0023] By changing the incident angle of the initial light source and simulating the optical behavior of light in the multilayer film superlens structure through software modeling, the electric field intensity and image contrast of the spatial image formed at the middle position of the photoresist coated on the substrate layer are obtained.

[0024] The present invention also provides a plasma superlens, which is optimized using the above-mentioned optimization method for mask absorption materials based on surface plasma multilayer film structures.

[0025] The present invention provides a method for optimizing a mask absorbing material based on a surface plasmon multilayer film structure, comprising the following steps: S1) constructing multiple sets of multilayer film superlens structures with different mask absorbing layer parameters; the multilayer film superlens structure comprises a multilayer film structure of quartz glass, multiple mask absorbing layers, a polymer spacer layer, and a metal-dielectric alternating stack; the multiple mask absorbing layers are disposed on the surface of the quartz glass; the polymer spacer layer is disposed between the multiple mask absorbing layers and on the surface of the multiple mask absorbing layers; the metal-dielectric alternating stacked multilayer film structure is disposed on the surface of the polymer spacer layer; S2) using software modeling to simulate the optical behavior of light in the multilayer film superlens structure, obtaining the image contrast of an aerial image formed at the center position of the photoresist coated on the substrate layer; S3) determining the mask absorbing layer parameters of the multilayer film superlens structure based on the image contrast. Compared with the prior art, the present invention optimizes the three-dimensional parameters of the mask absorbing layer based on the multilayer film structure, and the results show that it significantly improves the resolution and imaging contrast of the multilayer film structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of the imaging structure of a multilayer film superlens structure provided by the present invention;

[0027] FIG2 is a schematic structural diagram of the mask absorption layer parameters provided by the present invention;

[0028] FIG3 is a schematic diagram of a multilayer film superlens structure in which the mask absorption layer provided by the present invention is a MoSi layer and a Cr layer;

[0029] FIG4 is a graph showing the intensity contrast of the aerial image at different light source incident angles for two mask absorption layer materials, Cr and OMOG, both with a thickness of 60 nm and a side wall angle of 0°, according to an embodiment of the present invention;

[0030] FIG5 is a graph showing the intensity contrast of an aerial image of two mask absorption layer materials of Cr and OMOG with different thicknesses and a side wall angle θ=0° at vertical incidence in an embodiment of the present invention;

[0031] FIG6 shows the spatial image contrast results of two mask absorption layer materials, Cr and OMOG, with different side wall angles and a thickness of d=60 nm, at vertical incidence. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] The present invention provides an optimization method for a mask absorption material based on a surface plasma multilayer film structure, comprising the following steps: S1) constructing multiple groups of multilayer film superlens structures with different mask absorption layer parameters; the multilayer film superlens structure comprises quartz glass, multiple mask absorption layers, a multilayer film structure in which a polymer spacer layer and a metal-medium are alternately stacked; the multiple mask absorption layers are arranged on the surface of the quartz glass; the polymer spacer layer is arranged between the multiple mask absorption layers and on the surface of the multiple mask absorption layers; the multilayer film structure in which the metal-medium is alternately stacked is arranged on the surface of the polymer spacer layer; S2) simulating the optical behavior of light in the multilayer film superlens structure through software modeling to obtain the image contrast of an aerial image formed at the middle position of a photoresist coated on a substrate layer; S3) determining the mask absorption layer parameters of the multilayer film superlens structure according to the image contrast.

[0034] See Figure 1, which is a schematic diagram of the imaging structure of a multi-layer film super lens structure.

[0035] The present invention has no particular limitation on the sources of all raw materials, and any commercially available raw materials may be used.

[0036] Construct multiple groups of multilayer film superlens structures with different mask absorption layer parameters; the multilayer film superlens structure includes a multilayer film structure of quartz glass, multiple mask absorption layers, a polymer spacer and a metal-dielectric alternately stacked; the multiple mask absorption layers are arranged on the surface of the quartz glass; the slit width of the mask absorption layer is preferably 140-160nm, more preferably 150nm; the period of the mask absorption layer is preferably 280-320nm, more preferably 300nm; the thickness of the mask absorption layer is preferably 10-160nm; the mask absorption layer preferably includes a MoSi layer and / or a Cr layer, and when the mask absorption layer includes a MoSi layer and a Cr layer, the MoSi layer is in contact with the quartz; the side wall angle of the mask absorption layer, that is, the angle between the side wall and the vertical direction, is preferably 0°-30°; the polymer spacer is arranged between the multiple mask absorption layers and on the surface of the multiple mask absorption layers; The sub-polymer spacer layer can be a high molecular polymer spacer layer well known to those skilled in the art, and there is no special limitation. In the present invention, it is preferably a PMMA layer; the thickness of the high molecular polymer spacer layer is preferably 100-200 nm, more preferably 130-180 nm, and even more preferably 150-180 nm; the metal-dielectric alternating multilayer film structure is arranged on the surface of the high molecular polymer spacer layer; the metal-dielectric alternating multilayer film structure is a metal-dielectric alternating multilayer film structure well known to those skilled in the art, and in the present invention, it is preferably formed by alternating stacking of silver layers and titanium dioxide layers, and the titanium dioxide layer is close to the high molecular polymer spacer layer; the number of alternating stacking is preferably 3-8 times, more preferably 4-6 times, and even more preferably 5 times; the thickness of the metal-dielectric alternating multilayer film structure is preferably 250-350 nm, more preferably 280-320 nm, and even more preferably 300 nm. In the present invention, the construction of multiple groups of multilayer film superlens structures with different mask absorption layer parameters is preferably constructed using simulation software; the mask absorption layer parameters preferably include one or more of the thickness of the mask absorption layer, the material type of the mask absorption layer and the side wall angle of the mask absorption layer, and more preferably include one of the thickness of the mask absorption layer, the material type of the mask absorption layer and the side wall angle of the mask absorption layer; see Figure 2, Figure 2 is a structural schematic diagram of the mask absorption layer parameters; multiple groups of multilayer film superlens structures with different mask absorption layer parameters are preferably the same in structure except that the mask absorption layer parameters are set differently.

[0037] The optical behavior of light in a multilayer metalens structure is simulated by software modeling to obtain the image contrast of an aerial image formed at the center of the photoresist coated on the substrate layer. In the present invention, the optical behavior of light in a multilayer metalens structure is preferably simulated by software (FDTD solutions). The wavelength of the initial incident light source when simulating the optical behavior of light in a multilayer metalens structure by software modeling is preferably 300-400 nm, more preferably 320-380 nm, even more preferably 350-380 nm, and most preferably 365 nm. The initial incident light source is preferably TM polarized light; the angle of incidence of the initial incident light source is 0°-20°. The present invention uses the contrast of the aerial image at the center of the photoresist as the evaluation criterion. In the present invention, contrast represents the ratio between the lowest and highest points of the photoresist after exposure and development. In simulation calculations, the ratio of the difference between the maximum and minimum light intensity values ​​of the photoresist layer to the sum is generally used. This method of calculation is also called Michelson contrast. The higher the contrast, the higher the steepness of the pattern produced by the photolithography, that is, the better the resolution. For submicron graphics, it is generally required that positive photoresist graphics be greater than 0.4 and negative photoresist graphics be greater than 0.2. Where C is the contrast; I max is the maximum light intensity; I min is the minimum light intensity.

[0038] C=(I max -I min ) / (I max +I min )

[0039] According to the image contrast, the parameters of the mask absorption layer of the multilayer film super lens structure are determined.

[0040] In a specific embodiment provided by the present invention, the multiple groups of multilayer film superlens structures with different mask absorption layer parameters include multiple groups of multilayer film superlens structures with mask absorption layers being Cr layers of different thicknesses and multiple groups of multilayer film superlens structures with mask absorption layers being MoSi layers and Cr layers; see Figure 3, which is a schematic diagram of a multilayer film superlens structure with mask absorption layers being MoSi layers and Cr layers; in the multiple groups of multilayer film superlens structures with mask absorption layers being MoSi layers and Cr layers, the Cr layers have the same thickness, the MoSi layers have different thicknesses, and the MoSi layers are in contact with the quartz glass. The optical behavior of light in the multilayer film superlens structure is simulated by software modeling to obtain the electric field intensity and image contrast of the aerial image formed at the middle position of the photoresist coated on the substrate layer; and the mask absorption layer parameters of the multilayer film superlens structure are determined based on the electric field intensity and image contrast. The method of simulating the optical behavior of light in a multilayer film superlens structure through software modeling is the same as described above and will not be repeated here. In the present invention, the wavelength of the initial incident light source when simulating the optical behavior of light in a multilayer film superlens structure through software modeling is preferably 365 nm; the initial incident light source is preferably TM polarized light; the incident angle of the initial incident light source is 0°; through this optimization method, different mask absorption materials can be selected under different mask thicknesses to obtain better imaging contrast.

[0041] Further specifically, when there are multiple groups of multilayer film superlens structures with different mask absorption layer parameters, including multiple groups of multilayer film superlens structures in which the mask absorption layers are Cr layers of different thicknesses and multiple groups of multilayer film superlens structures in which the mask absorption layers are MoSi layers and Cr layers, the other mask absorption layer parameters of the multilayer film superlens structures are the same; preferably, the side wall angle of the mask absorption layer (the longitudinal cross-section of the mask absorption layer is a trapezoid that is narrow at the top and wide at the bottom, and the side wall angle is the angle between the side wall and the vertical direction) is 0°.

[0042] Further specifically, when a multilayer film superlens structure having different mask absorption layer parameters is formed, including a multilayer film superlens structure in which multiple groups of mask absorption layers are Cr layers of different thicknesses and a multilayer film superlens structure in which multiple groups of mask absorption layers are MoSi layers and Cr layers, the thickness of the mask absorption layer of the multilayer film superlens structure in which multiple groups of mask absorption layers are Cr layers of different thicknesses is 10 to 160 nm, and the thickness gradient increases; the gradient-increasing thickness is preferably 5 to 20 nm, more preferably 5 to 15 nm, and more preferably 10 nm; the thickness of the Cr layer in the multilayer film superlens structure in which multiple groups of mask absorption layers are MoSi layers and Cr layers is the same, preferably 5 to 20 nm, more preferably 5 to 15 nm, and more preferably 10 nm; the thickness of the MoSi layer in the multilayer film superlens structure in which multiple groups of mask absorption layers are MoSi layers and Cr layers is different, preferably 0 to 150 nm, and the thickness gradient increases; the gradient-increasing thickness is preferably 5 to 20 nm, more preferably 5 to 15 nm, and more preferably 10 nm.

[0043] In another specific embodiment provided by the present invention, the multiple groups of multilayer film super lens structures with different mask absorption layer parameters include multiple groups of multilayer film super lens structures with different side wall angles of the mask absorption layer. The optical behavior of light in the multilayer film super lens structure is simulated by software modeling to obtain the electric field intensity and image contrast of the spatial image formed at the middle position of the photoresist coated on the substrate layer; according to the electric field intensity and image contrast, the mask absorption layer parameters of the multilayer film super lens structure are determined. The method of simulating the optical behavior of light in the multilayer film super lens structure by software modeling is the same as described above and will not be repeated here. In the present invention, the wavelength of the initial incident light source when simulating the optical behavior of light in the multilayer film super lens structure by software modeling is preferably 365nm; the initial incident light source is preferably TM polarized light; the incident angle of the initial incident light source is 0°; through this optimization method, the sensitivity of different mask absorption materials to changes in side wall angles can be known, thereby obtaining better imaging contrast.

[0044] More specifically, in the multilayer film superlens structure with different side wall angles of multiple groups of mask absorption layers, the mask absorption layer parameters are the same except for the material type of the mask absorption layer; wherein the mask absorption layer preferably includes a MoSi layer and / or a Cr layer, and when the mask absorption layer includes a MoSi layer and a Cr layer, the MoSi layer is in contact with the quartz glass; when the mask absorption layer includes a MoSi layer and a Cr layer; the thickness ratio of the MoSi layer to the Cr layer is preferably (3 to 6):1, more preferably (4 to 6):1, and further preferably 5:1; the thickness of the mask absorption layer is preferably 10 to 160 nm; the thickness of the mask absorption layer can be any point value within the above range without special limitation; in the embodiment provided by the present invention, a thickness of 60 nm is specifically used as an example for illustration.

[0045] To be more specific, the side wall angle of the multilayer film superlens structure with different side wall angles of multiple groups of mask absorption layers is 0°~30°, and the gradient increases; the degree of the gradient increase is preferably 1°~10°, more preferably 2°~8°, further preferably 4°~6°, and most preferably 8°.

[0046] In another specific embodiment provided by the present invention, when software modeling is used to simulate the optical behavior of light in a multilayer film superlens structure, the incident angle of the initial incident light source is 0° to 20°. The optical behavior of light in the multilayer film superlens structure is simulated by changing the incident angle of the initial light source, thereby obtaining the electric field intensity and image contrast of the aerial image formed at the center position of the photoresist coated on the substrate layer. This optimization method can be used to select different mask absorbing materials according to different process conditions, thereby achieving better imaging contrast.

[0047] Further specifically, in this embodiment, in multiple groups of multilayer film superlens structures with different mask absorption layer parameters, the mask absorption layer parameters are the same except for the material type of the mask absorption layer; wherein, the mask absorption layer preferably includes a MoSi layer and / or a Cr layer, and when the mask absorption layer includes a MoSi layer and a Cr layer, the MoSi layer is in contact with the quartz glass; when the mask absorption layer includes a MoSi layer and a Cr layer; the thickness ratio of the MoSi layer to the Cr layer is preferably (3 to 6):1, more preferably 5:1; the thickness of the mask absorption layer is preferably 10 to 160 nm; the thickness of the mask absorption layer can be any point value within the above range without special limitation; in the embodiment provided in the present invention, a thickness of 60 nm is specifically used as an example for illustration; the side wall angle of the mask absorption layer is preferably 0°.

[0048] More specifically, the incident angle of the initial light source is preferably changed in a gradient increase; the degree of the gradient increase is preferably 1° to 5°, more preferably 2° to 4°, and even more preferably 2° to 3°.

[0049] In the present invention, further optimization can be performed in combination with the above three specific implementations, such as obtaining the thickness of the mask absorption layer according to the incident angle of the initial light source and the material of the mask absorption layer.

[0050] The present invention is based on a multilayer film structure and optimizes the three-dimensional parameters of the mask absorption layer. The results show that the multilayer film structure has a significant effect on improving the resolution and imaging contrast.

[0051] The present invention also provides a plasma superlens, which is optimized using the above-mentioned optimization method for mask absorption materials based on surface plasma multilayer film structures.

[0052] To further illustrate the present invention, the following describes in detail a method for optimizing a mask absorbing material based on a surface plasma multilayer film structure and a plasma superlens in combination with embodiments.

[0053] The reagents used in the following examples are all commercially available.

[0054] Example 1

[0055] The present invention mainly uses the illumination source for exciting deep subwavelength bulk surface plasmons, which is composed of a metal-dielectric alternating multilayer film structure as shown in Figure 1, as an optimized embodiment structure. This optimization method can also be applied to the optimization of other similar structures.

[0056] The multilayer film structure is as follows: 365nm TM-polarized incident light is incident obliquely on the mask surface at an angle of incidence α. The chromium metal mask absorber layer is fabricated on quartz glass with a 150nm slit width and a 300nm period. The entire lens structure comprises five layers of uniform Ag / TiO2 composite thin film (total 300nm). The process requires filling the mask with a 150nm thick layer of PMMA material whose dielectric constant matches the real part of the Ag film. A detailed schematic diagram of the mask structure used in the simulation is shown in Figure 2. The mask absorber layer material thickness is dnm, and the sidewall angle is θ°. The photoresist thickness is 50nm, and all components in the y-direction are considered infinite.

[0057] Based on this structure, the material of the mask absorption layer is optimized to see whether the contrast of the aerial image in the middle of the photoresist is improved (the contrast of the aerial image in the middle of the photoresist is used as an evaluation index).

[0058] The optical behavior of light in the structure was simulated using software (FDTD solutions), and the electric field intensity and image contrast of the aerial image at the center of the photoresist were calculated to compare and evaluate the optimization effect.

[0059] The material for the mask absorber layer was optimized. In this example, Cr (chromium) was selected with a thickness of d nm. OMOG (opaque MoSi on glass) was used. A schematic diagram of OMOG is shown in Figure 3. The OMOG mask absorber thickness is set to CR (10 nm) + MoSi (d - 10 nm), with a sidewall angle of θ.

[0060] Definition and explanation of physical quantities:

[0061] Contrast: It refers to the ratio between the lowest point and the highest point of the photoresist after exposure and development. In simulation calculations, the ratio of the difference between the maximum and minimum light intensity of the photoresist layer to the sum is generally used. This method of calculation is also called Michelson contrast. The higher the contrast, the higher the steepness of the pattern that can be produced by the lithography, that is, the better the resolution. For sub-micron graphics, it is generally required that the positive photoresist pattern is greater than 0.4 and the negative photoresist pattern is greater than 0.2. Among them, C is the contrast; I max is the maximum light intensity; I min is the minimum light intensity.

[0062] C=(I max -I min ) / (I max +I min )

[0063] Figure 4 shows the spatial image intensity contrast results for two mask absorber types: Cr and OMOG (Cr 10nm + MoSi 50nm), with a thickness d of 60nm and a sidewall angle θ of 0°, at different light source incident angles. The results show that when the light source incident angle α ranges from 0° to 6°, the CR mask has a higher contrast than the OMOG mask. When the light source incident angle α ranges from 6° to 18°, the OMOG mask has a higher contrast than the Cr mask. This conclusion demonstrates that optimizing image contrast can be achieved by selecting different mask absorber materials based on different process conditions.

[0064] Figure 5 shows the aerial image intensity contrast results at normal incidence for masks made of two different mask absorber materials, Cr and OMOG, with a sidewall angle θ = 0°. The different thicknesses here refer to increasing the Cr thickness from 10nm to 160nm for Cr; and increasing the MoSi thickness from 0nm to 150nm for OMOG, while maintaining the Gr layer at 10nm. As shown in Figure 5, the contrast of OMOG structures and Cr masks of varying thickness exhibits different adaptability and trends. The results show that at normal incidence, the Cr mask exhibits higher contrast than the OMOG mask for mask thicknesses ranging from 0nm to 80nm. For mask thicknesses ranging from 80nm to 160nm, the OMOG mask exhibits higher contrast than the Cr mask. Based on these experimental results, selecting different mask absorber materials for different mask thicknesses can achieve optimal image contrast.

[0065] Figure 6 shows the aerial image contrast results at normal incidence for two mask absorber layers: Cr (d = 60nm) and OMOG (Cr 10nm + MoSi 50nm), with a thickness of d = 60nm. The results show that, at this thickness setting, increasing the sidewall angle leads to different trends in mask contrast for the two structures. The Cr mask is more sensitive to changes in sidewall angle, with contrast gradually increasing with increasing sidewall angle. However, for the OMOG mask structure, increasing the sidewall angle has no significant effect on contrast.

[0066] The preferred embodiments of the present invention disclosed above are merely intended to help illustrate the present invention, but the present invention is not limited thereto. Those skilled in the art will appreciate that, within the scope of the technical concept of the present invention, the technical solutions of the present invention may be modified, or some of the technical features may be combined in any other manner. Such modifications or combinations do not deviate from the essence of the corresponding technical solutions from the spirit and scope of the various technical solutions of the present invention, and should be regarded as the contents disclosed by the present invention and fall within the scope of protection of the present invention.

Claims

1. An optimization method for a mask absorbing material based on a surface plasmon multi-layer film structure, characterized in that It includes the following steps: S1) Construct multilayer film superlens structures with multiple groups of mask absorption layer parameters; the multilayer film superlens structure includes fused quartz, multiple mask absorption layers, a polymer spacer layer, and a multilayer film structure with alternating metal and dielectric stacks; the multiple mask absorption layers are disposed on the surface of the fused quartz; the polymer spacer layer is disposed between the multiple mask absorption layers and on the surface of the multiple mask absorption layers; the multilayer film structure with alternating metal and dielectric stacks is disposed on the surface of the polymer spacer layer; S2) Through software modeling and simulation of the optical behavior of light in the multilayer film superlens structure, obtain the image contrast of the spatial image formed at the middle position of the photoresist coated on the substrate layer; S3) Determine the mask absorption layer parameters of the multilayer film superlens structure according to the image contrast.

2. The optimization method according to claim 1, wherein The parameters of the mask absorption layer include one or more of the thickness of the mask absorption layer, the material type of the mask absorption layer, and the sidewall angle of the mask absorption layer.

3. The optimization method according to claim 2, characterized in that The thickness of the mask absorption layer is 10 to 160 nm; the mask absorption layer includes a MoSi layer and / or a Cr layer, and when the mask absorption layer includes a MoSi layer and a Cr layer, the MoSi layer is in contact with the fused quartz; the sidewall angle of the mask absorption layer is 0° to 30°.

4. The optimization method according to claim 2, characterized in that, The multiple groups of multilayer film superlens structures with different mask absorption layer parameters include multilayer film superlens structures with multiple groups of Cr layers of different thicknesses as the mask absorption layer and multilayer film superlens structures with multiple groups of mask absorption layers being MoSi layers and Cr layers; In the multiple groups of multilayer film superlens structures with mask absorption layers being MoSi layers and Cr layers, the thickness of the Cr layer is the same, the thickness of the MoSi layer is different, and the MoSi layer is in contact with the fused quartz.

5. The optimization method according to claim 2, wherein The multiple groups of multilayer film superlens structures with different mask absorption layer parameters include multilayer film superlens structures with different sidewall angles of the mask absorption layer.

6. The optimization method according to claim 1, wherein The slit width of the mask absorption layer is 140 to 160 nm; the period of the mask absorption layer is 280 to 320 nm.

7. The optimization method according to claim 1, wherein The thickness of the polymer spacer layer is 100 to 200 nm; The thickness of the multilayer film structure with alternating metal and dielectric stacks is 250 to 350 nm.

8. The optimization method according to claim 1, characterized in that, The polymer spacer layer is a PMMA layer; The multilayer film structure with alternating metal and dielectric stacks is formed by alternating silver layers and titanium dioxide layers, and the layer close to the polymer spacer layer is a titanium dioxide layer.

9. The optimization method according to claim 1, characterized in that When performing software modeling and simulation of the optical behavior of light in the multilayer film superlens structure in step S2), the incident angle of the initial incident light source is 0° to 20°; Change the incident angle of the initial light source and perform software modeling and simulation of the optical behavior of light in the multilayer film superlens structure to obtain the electric field strength and image contrast of the spatial image formed at the middle position of the photoresist coated on the substrate layer.

10. A plasma superlens, characterized in that, It is optimized by using the optimization method of the mask absorption material based on the surface plasmon multilayer film structure described in any one of claims 1 to 9.

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