Method, device, electronic device, medium and program product for optimizing photolithography quality

Abstract

The present disclosure provides a method for optimizing photolithography quality, comprising: determining wave function stray terms introduced by the surface roughness of a metal film layer based on the characteristic matrix method and Bloch's theorem; inputting the wave function stray terms into a mathematical model for photolithography quality deviation for computational simulation, thereby obtaining an analysis curve for the impact of the metal film layer roughness on photolithography quality, the curve representing the impact of the metal film layer roughness on photolithography quality; and, based on the impact results, reducing the surface roughness of the metal film layer and / or disposing a metal-dielectric multilayer film structure between a mask located above a metal-dielectric unit and air, thereby optimizing the photolithography quality of the metal-dielectric unit. The present disclosure also provides a device for optimizing photolithography quality, an electronic device, a computer-readable storage medium, and a computer program product.

Description

Technical Field

[0001] The present disclosure relates to the field of nanolithography and optical metrology, and in particular to a method, device, electronic device, medium, and program product for optimizing lithography quality. Background Art

[0002] Surface plasmons propagate as evanescent waves bound to the metal-dielectric interface. Evanescent waves exhibit exponential decay, and the periodic distribution of metal-dielectric units allows for coupling, amplification, transmission, convergence, and imaging of these waves. Therefore, surface plasmon-based nanolithography uses the periodic distribution of metal-dielectric units to expose and image the pattern on the mask into the photoresist. The reliability and stability of the nanolithography process depends on the contrast and intensity of the photoresist's aerial image. Therefore, the surface roughness of the metal film layer has a significant impact on the quality of nanolithography. Summary of the Invention

[0003] To address the problems existing in the prior art, the embodiments of the present disclosure provide a method, device, electronic device, medium and program product for optimizing lithography quality, which optimizes the lithography quality of metal-dielectric units based on an analysis of the impact of metal film roughness on lithography quality.

[0004] A first aspect of the present disclosure provides a method for optimizing photolithography quality, comprising: determining wave function stray terms introduced by the surface roughness of a metal film layer based on a characteristic matrix method and Bloch's theorem; inputting the wave function stray terms into a mathematical model of photolithography quality deviation for computational simulation, thereby obtaining an analysis curve of the impact of the roughness of the metal film layer on the photolithography quality, wherein the analysis curve represents the impact of the roughness of the metal film layer on the photolithography quality; and, based on the impact results, reducing the surface roughness of the metal film layer and / or providing a metal-dielectric multilayer film structure between a mask plate located above a metal-dielectric unit and air, thereby optimizing the photolithography quality of the metal-dielectric unit.

[0005] Furthermore, based on the characteristic matrix method and Bloch's theorem, the wave function stray terms introduced by the surface roughness of the metal film layer are determined, including: obtaining the characteristic matrix of the single-layer film in the metal-dielectric unit according to the characteristic matrix method; obtaining the unit characteristic matrix of the metal-dielectric unit according to the characteristic matrix of the single-layer film; based on the Bloch's theorem and the unit characteristic matrix, determining the change term introduced by the film thickness caused by the roughness of the metal film layer, and then obtaining the wave function stray terms introduced by the surface roughness of the metal film layer.

[0006] Furthermore, the characteristic matrix M of the single-layer film n (k x , t n ) satisfies the following relationship:

[0007]

[0008] Among them, k x represents the wave vector of the evanescent wave along the x-axis, t n represents the thickness of the single layer film, k zn represents the wave vector of the electromagnetic wave along the z axis, k0 represents the wave vector in vacuum, ε0 represents the dielectric constant of vacuum, ε n Represents the dielectric constant of a single layer.

[0009] Furthermore, the unit characteristic matrix M of the metal-dielectric unit unit (k x , t n ) satisfies the following relationship:

[0010]

[0011] Among them, t n =t m =t d , t m Indicates the thickness of the metal layer, t d represents the thickness of the dielectric layer, k zm represents the wave vector of the electromagnetic wave along the z axis in the metal layer, k zd represents the wave vector of the electromagnetic wave along the z axis in the dielectric layer, ε m is the dielectric constant of the metal layer.

[0012] Furthermore, the wave function stray term Δψ(z′) introduced by the surface roughness of the metal film layer satisfies the following relationship:

[0013] Δψ(z′)=exp(-ik z (t m +Δt+t d ))ψ(z)

[0014] Among them, k z represents the wave vector of the evanescent wave along the z-axis, ψ(z) represents the normalized wave function of the transverse magnetic wave in the xz plane, and Δt represents the film thickness t caused by the roughness of the metal film layer. m Introducing the variable term, z′=z+t m +t d , z represents the coordinate of the electromagnetic wave, and z′ represents the coordinate of the electromagnetic wave passing through a metal-dielectric unit.

[0015] Furthermore, the wave function stray term is input into the mathematical model of lithography quality deviation for calculation and simulation, and an analysis curve of the influence of metal film roughness on lithography quality is obtained, including:

[0016] The wave function stray terms are input into the mathematical model of lithography quality deviation for calculation and simulation to obtain the energy density distribution results of the metal-dielectric unit; based on the energy density distribution results, an analysis curve of the influence of the roughness of the metal film layer on the lithography quality is obtained.

[0017] Furthermore, before the step of determining the wave function stray terms introduced by the surface roughness of the metal film layer, the method also includes: using an atomic force microscope to test the upper surface morphology of the metal film layer; using a template peeling and flipping technology to test the lower surface morphology of the metal film layer; and obtaining the surface roughness of the metal film layer based on the upper surface morphology and the lower surface morphology.

[0018] Furthermore, the metal-dielectric unit is composed of at least one metal film layer, and the dielectric layer in the metal-dielectric unit is located between the metal film layers.

[0019] Furthermore, the metal film layer is composed of one or more of Ag, Al, and Au.

[0020] Furthermore, the metal-dielectric multilayer film structure is an Ag-SiO2 multilayer film structure.

[0021] A second aspect of the present disclosure provides a device for optimizing photolithography quality, comprising: a wave function stray term determination module, configured to determine the wave function stray terms introduced by the surface roughness of a metal film layer based on a characteristic matrix method and Bloch's theorem; a simulation module, configured to input the wave function stray terms into a photolithography quality deviation mathematical model for computational simulation, thereby obtaining an analysis curve of the influence of the roughness of the metal film layer on the photolithography quality, wherein the analysis curve represents the influence of the roughness of the metal film layer on the photolithography quality; and a photolithography quality optimization module, configured to reduce the roughness of the surface of the metal film layer and / or set a metal-dielectric multilayer film structure between a mask plate located above the metal-dielectric unit and the air, based on the influence results, to optimize the photolithography quality of the metal-dielectric unit.

[0022] The third aspect of the present disclosure provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for optimizing lithography quality provided by the first aspect of the present disclosure is implemented.

[0023] A fourth aspect of the present disclosure provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for optimizing lithography quality provided by the first aspect of the present disclosure is implemented.

[0024] A fifth aspect of the present disclosure provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method for optimizing lithography quality provided by the first aspect of the present disclosure.

[0025] The present disclosure provides a method, device, electronic device, computer-readable storage medium, and computer program product for optimizing photolithography quality. The method uses a characteristic matrix method and Bloch's theorem to determine the wave function stray terms introduced by the surface roughness of a metal film layer. Numerical simulation is performed in conjunction with the wave function stray terms to analyze the impact of the metal film layer roughness on the photolithography quality. This improves the photolithography quality of the metal-dielectric unit and thereby reduces the line edge roughness of the photoresist pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For a more complete understanding of the present disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0027] Figure 1 The flowchart of the method for optimizing photolithography quality according to an embodiment of the present disclosure is schematically shown;

[0028] Figure 2 Schematically shows a structural diagram of a metal-dielectric unit according to an embodiment of the present disclosure;

[0029] Figure 3 Schematically shows Figure 2 Schematic diagram of the Poynting vector distribution of the metal-dielectric unit shown;

[0030] Figure 4 Schematically shows Figure 2 Schematic diagram of normalized light intensity distribution at the center of the photoresist of the metal-dielectric unit shown;

[0031] Figure 5 Schematically shows Figure 2 A schematic diagram of a curve showing the light intensity contrast in the photoresist and the surface roughness of the Ag layer;

[0032] Figure 6 Schematically shows a structural diagram of a metal-dielectric unit according to yet another embodiment of the present disclosure;

[0033] Figure 7 Schematically shows Figure 6 Schematic diagram of the Poynting vector distribution of the metal-dielectric unit shown;

[0034] Figure 8 Schematically shows Figure 6 Schematic diagram of normalized light intensity distribution at the center of the photoresist of the metal-dielectric unit shown;

[0035] Figure 9 Schematically shows Figure 6 A schematic diagram of a curve showing the light intensity contrast in the photoresist and the surface roughness of the Ag layer;

[0036] Figure 10Schematically shows a structural diagram of a metal-dielectric unit according to another embodiment of the present disclosure;

[0037] Figure 11 Schematically shows Figure 10 Schematic diagram of the Poynting vector distribution of the metal-dielectric unit shown;

[0038] Figure 12 Schematically shows Figure 10 Schematic diagram of normalized light intensity distribution at the center of the photoresist of the metal-dielectric unit shown;

[0039] Figure 13 Schematically shows Figure 10 A schematic diagram of a curve showing the light intensity contrast in the photoresist and the surface roughness of the Ag layer;

[0040] Figure 14 Schematically shows a block diagram of a device for optimizing lithography quality according to an embodiment of the present disclosure;

[0041] Figure 15 The block diagram schematically shows an electronic device suitable for implementing the method described above according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0043] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0044] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0045] When expressions such as “at least one of A, B, and C, etc.” are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (e.g., “a system having at least one of A, B, and C” should include but is not limited to systems having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, and C, etc.). When expressions such as “at least one of A, B, or C, etc.” are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (e.g., “a system having at least one of A, B, or C” should include but is not limited to systems having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, and C, etc.).

[0046] Some block diagrams and / or flow charts are shown in the accompanying drawings. It should be understood that some blocks in the block diagrams and / or flow charts or their combinations can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that these instructions, when executed by the processor, can create a device for implementing the functions / operations described in these block diagrams and / or flow charts. The technology of the present disclosure can be implemented in the form of hardware and / or software (including firmware, microcode, etc.). In addition, the technology of the present disclosure can take the form of a computer program product on a computer-readable storage medium having instructions stored thereon, which can be used by an instruction execution system or in combination with an instruction execution system.

[0047] The roughness of the film layer is divided into long-range and short-range roughness. The long-range roughness is caused by the average error in the film layer processing process, and the short-range roughness is caused by random defects at a certain point in the film layer processing process. The present disclosure mainly focuses on the long-range roughness RMS in the film layer processing process, and analyzes the average surface error in the processing process, which causes the deviation between the photoresist spatial image and the ideal image. Surface plasma is transmitted through periodically arranged metal dielectric units. The surface roughness RMS of the metal film layer is distributed in the range of 0 to 2 nm. The influence of the roughness of the metal film layer on the photolithography quality is not only reflected in the reduction of imaging resolution, but also the energy of the electromagnetic field will decay rapidly as the roughness of the film layer increases. In specific implementation, the influence of the surface roughness of the metal film layer on the imaging quality in the photoresist is mainly analyzed based on the light intensity contrast.

[0048] Figure 1 The flowchart of the method for optimizing the photolithography quality according to the embodiment of the present disclosure is schematically shown. Figure 1 As shown, the method includes: steps S101 to S103.

[0049] In operation S101 , based on the characteristic matrix method and Bloch's theorem, a wave function stray term introduced by the surface roughness of the metal film layer is determined.

[0050] In operation S102 , the wave function stray term is input into a mathematical model of lithography quality deviation for calculation and simulation to obtain an analysis curve of the influence of the metal film roughness on the lithography quality. The analysis curve represents the influence of the metal film roughness on the lithography quality.

[0051] In operation S103 , based on the impact result, the roughness of the metal film surface is reduced and / or a metal-dielectric multilayer film structure is provided between the mask and the air above the metal-dielectric unit to optimize the lithography quality of the metal-dielectric unit.

[0052] The following describes in detail an exemplary process of each step of the method for optimizing photolithography quality according to this embodiment.

[0053] In an embodiment of the present disclosure, before determining the wave function stray terms introduced by the surface roughness of the metal film layer based on the characteristic matrix method and Bloch's theorem, the method also includes: using an atomic force microscope to test the upper surface morphology of the metal film layer; using a template peeling and flipping technique to test the lower surface morphology of the metal film layer; and obtaining the surface roughness of the metal film layer based on the upper surface morphology and the lower surface morphology.

[0054] Furthermore, according to the obtained surface roughness of the metal film layer, based on the characteristic matrix method and Bloch's theorem, the wave function stray terms introduced by the surface roughness of the metal film layer are determined.

[0055] Specifically, determining the wave function stray terms introduced by the surface roughness of the metal film layer includes: obtaining the characteristic matrix of the single-layer film in the metal-dielectric unit according to the characteristic matrix method; obtaining the unit characteristic matrix of the metal-dielectric unit according to the characteristic matrix of the single-layer film; based on the Bloch theorem and the unit characteristic matrix, determining the change term introduced by the film thickness caused by the roughness of the metal film layer, and then obtaining the wave function stray terms introduced by the surface roughness of the metal film layer.

[0056] Based on the characteristic matrix method, the thickness is t n The characteristic matrix M of the single layer film n (k x , t n ) satisfies the following relationship:

[0057]

[0058] Among them, k x represents the wave vector of the evanescent wave along the x-axis, t n represents the thickness of the single layer film, k znrepresents the wave vector of the electromagnetic wave along the z axis, k0 represents the wave vector in vacuum, ε0 represents the dielectric constant of vacuum, ε n The dielectric constant of a single-layer film is represented by . The thickness of the single-layer film in the above formula refers to the thickness of the metal film or the dielectric layer.

[0059] The evanescent wave meets the boundary continuity condition in the metal-dielectric periodically arranged multilayer film, that is, at the interface between the metal and the dielectric, the wave vector k of the evanescent wave along the x-axis is x Has invariance, that is, k x =k xd =k xm , k xd represents the wave vector of the electromagnetic wave along the x-axis in the dielectric layer, k xm Represents the wave vector of the electromagnetic wave along the x-axis in the metal film layer.

[0060] According to the feature matrix M n (k x , t n ), we can get the unit characteristic matrix M of the metal-dielectric unit unit (k x , t), which satisfies the following relationship:

[0061]

[0062] Among them, M m and M d are the characteristic matrices of the metal layer and dielectric layer respectively, m 11 、m 12 、m 13 、m 14 They are the unit feature matrix M unit (k x , t n ) of each element. n =t m =t d , t m Indicates the thickness of the metal layer, t d represents the thickness of the dielectric layer, k zm represents the wave vector of the electromagnetic wave along the z axis in the metal layer, k zd represents the wave vector of the electromagnetic wave along the z axis in the dielectric layer, ε m is the dielectric constant of the metal layer, ε d is the dielectric constant of the dielectric layer.

[0063] Combining the characteristic matrix method and Bloch's theorem, the wave function ψ(z) in the periodic arrangement system is:

[0064] ψ(z′)=exp(-ik z (t m +td ))ψ(z)

[0065] The wave function ψ(z) represents the normalized wave function of the transverse magnetic wave in the xz plane, and its electric field along the x-axis and z-axis can be expressed as:

[0066]

[0067]

[0068] Among them, k xn 、k zn is the wave vector of the transverse magnetic wave along the x-axis and z-axis; ω is the angular frequency; the wave function after one metal-medium cycle is ψ(z′). Where z′=z+t m +t d , z represents the coordinate of the electromagnetic wave, and z′ represents the coordinate of the electromagnetic wave passing through a metal-dielectric unit.

[0069] Determine the thickness t of the metal film due to the roughness of the film m The introduced variation term Δt, thus obtaining the wave function stray term Δψ(z′) introduced by the surface roughness of the metal film layer, can be expressed as:

[0070] Δψ(z′)=exp(-ik z (t m +Δt+t d ))ψ(z)

[0071] Among them, k z represents the wave vector of the evanescent wave along the z-axis, ψ(z) represents the normalized wave function of the transverse magnetic wave in the xz plane, and Δt represents the film thickness t caused by the roughness of the metal film layer. m Introducing a variable.

[0072] Based on the characteristic matrix method and Bloch's theorem, the surface roughness RMS is introduced into the thickness t of the metal film layer. m In the analysis, the nanoscale fluctuations in film thickness lead to the evanescent wave vector (k x , k z ) changes in the two-dimensional spatial distribution. (k x , k z ) causes the change in the phase of the electromagnetic field, which in turn affects the resolution of the lithographic imaging; (k x , k z ) determines the attenuation of the electromagnetic field, which affects the size of the device and the effective depth of focus in the photoresist.

[0073] According to an embodiment of the present disclosure, the wave function stray term is input into the mathematical model of lithography quality deviation for calculation and simulation, and an analysis curve of the influence of the roughness of the metal film layer on the lithography quality is obtained, including: inputting the wave function stray term into the mathematical model of lithography quality deviation for calculation and simulation, and obtaining the energy density distribution result of the metal-dielectric unit; and obtaining the analysis curve of the influence of the roughness of the metal film layer on the lithography quality based on the energy density distribution result.

[0074] Specifically, the wave function stray term obtained in step S101 is input into the mathematical model of lithography quality deviation, which is a simulation model of the metal-dielectric unit. The finite element analysis method is used for simulation calculation to obtain an analysis curve of the influence of the roughness of the metal film layer on the lithography quality. The influence analysis curve represents the influence of the roughness of the metal film layer on the lithography quality, which can be used to measure the lithography quality through the lithography imaging contrast.

[0075] Based on the lithographic imaging contrast, the surface roughness of the metal film layer or the imaging structure of the metal-dielectric unit is further optimized. Specifically, the surface roughness of the metal film layer is reduced, and / or a metal-dielectric multilayer structure is provided between the mask and the air above the metal-dielectric unit to optimize the lithographic quality of the metal-dielectric unit and thereby reduce the line edge roughness of the photoresist pattern. The metal-dielectric multilayer structure can be, for example, an Ag-SiO2 multilayer structure.

[0076] In the embodiments of the present disclosure, a metal-dielectric unit is composed of at least one metal film layer, with the dielectric layer located between the metal film layers. For example, the metal-dielectric unit can be an imaging structure in the form of photoresist-silver composed of Ag-Pr, or a resonant cavity lens structure composed of Ag-Pr-Ag, wherein the Pr layer is located on the surface of the Ag layer or between multiple Ag layers. Specifically, the metal film layer can be composed of one or more of Ag, Al, and Au.

[0077] It should be noted that the metal film layer and the metal-dielectric multilayer film structure are not limited to the types shown in the above embodiments. They can be set according to actual application conditions, and the embodiments of the present disclosure do not limit this.

[0078] The optimization method provided by the present disclosure will be described in detail below with reference to specific embodiments. It should be understood that Figures 2 to 13 The structure of the metal-dielectric unit and the experimental results shown in the figure are merely exemplary to help those skilled in the art understand the technical solution of the present disclosure, and are not intended to limit the scope of protection of the present disclosure.

[0079] Example 1

[0080] like Figure 2As shown, the metal-dielectric unit structure is an imaging structure based on the photoresist-silver form, specifically: a silicon dioxide substrate 10, an Ag layer 20, a photoresist layer 30, a periodic chromium stripe layer 40 and a mask substrate 50, wherein the mask substrate 50 is quartz, the Ag layer 20 and the photoresist layer 30 are sequentially located on the silicon dioxide substrate 10, and there is air between the periodic chromium stripe layer 40 and the photoresist layer 30.

[0081] like Figure 2 As shown, under ideal conditions, the wavelength of the incident monochromatic light source is 365 nm. A transverse magnetic wave is incident, so the magnetic field vibrates downward, perpendicular to the incident direction of the transverse magnetic wave. The dielectric constant of the mask substrate, quartz, is 2.25. The mask consists of a mask substrate 50 and six chromium (Cr) strips 40, with air filling the spaces between the strips.

[0082] In this embodiment, the dielectric constant of the metal Cr is -8.55-8.96i, the thickness of the Cr strip is 40nm, and the width of the Cr, i.e., the line width of the mask, is 120nm. The thickness of the air layer between the mask and the photoresist is 15nm. Along the positive z-axis of the beam propagation, the electromagnetic wave passes through the air layer before reaching the photoresist layer. The thickness of the photoresist layer is 30nm, and the dielectric constant of the photoresist is 2.59. The thickness of the Ag layer under the photoresist is 50nm, and the dielectric constant is -2.4-0.24i. The substrate is silicon dioxide SiO2, and there are no special requirements for the thickness of the SiO2. In this embodiment, the thickness of the SiO2 substrate is 20nm, and the dielectric constant is 2.17. Of the above parameters, the thickness of the air layer has the greatest impact on the imaging quality of the photoresist aerial image. Due to the exponential decay characteristics of the evanescent wave, the spacing between the air layers is on the scale of tens of nanometers. Similarly, the silver layer 20 under the photoresist mainly plays a role in enhancing the reflection of the electromagnetic field in the photoresist. Therefore, the thickness of the silver layer has little effect on the electric field strength, but the surface roughness of the silver layer 20 has an important influence on the light intensity contrast.

[0083] Based on the finite element analysis method and the numerical simulation calculation of the wave function stray term introduced by the surface roughness of the metal film layer, the Poynting vector distribution in the two-dimensional plane is obtained, such as Figure 3 The Poynting vector is the power flow distribution of the electromagnetic field per unit time, also known as the time-averaged power flow, with the unit of W / m 2 Based on the Poynting vector, the electromagnetic field energy distribution in the photoresist is obtained, that is, the energy density distribution result of the metal-dielectric unit.

[0084] Based on the energy density distribution results of the metal-dielectric unit, the normalized light intensity distribution diagram of the photoresist center of the imaging structure based on the photoresist-silver form can be obtained in turn, such as Figure 4 As shown in the figure, as well as the analysis curve of the influence of the roughness of the metal film layer on the photolithography quality in the imaging structure based on the photoresist-silver form, as shown in the figure. Figure 5 shown.

[0085] like Figure 4 As shown in the figure, as the RMS roughness of the film increases from 0.1nm to 0.7nm, the light intensity gradually decreases. The smoother the film, the greater the light intensity at the center of the photoresist. As the roughness of the underlying silver film increases, the electromagnetic wave energy concentrates at the interface between the photoresist and the Ag layer, and the proportion of stray waves distributed at this interface due to the film roughness increases.

[0086] like Figure 5 As shown in the figure, the RMS film roughness increases from 0.1nm to 0.4nm, while the intensity contrast ratio decreases from 0.989 to 0.972, showing no significant decrease in contrast. The RMS film roughness increases from 0.4nm to 0.7nm, while the intensity contrast ratio increases from 0.972 to 0.986. For the Pr-Ag imaging structure, the intensity contrast ratio remains above 0.97 within the film roughness range of 0.1nm to 0.7nm. The roughness of the Ag layer under the photoresist has little impact on the imaging quality of the aerial image in the photoresist.

[0087] Example 2

[0088] The structure of the metal-dielectric unit in this embodiment is as follows Figure 6 As shown, the difference between this embodiment and embodiment 1 is:

[0089] In this embodiment, the structure of the metal-dielectric unit is a resonant cavity lens, that is, a silver-photoresist-silver (Ag-Pr-Ag) structure, such as Figure 6 An upper silver layer 20 is provided on the photoresist 30 , and the thickness of the upper silver layer 20 is 20 nm. Other parameters are the same as those in Example 1.

[0090] Similarly, based on the finite element analysis method and combined with the wave function stray terms introduced by the surface roughness of the metal film layer, the Poynting vector distribution in the two-dimensional plane is obtained, such as Figure 7 Compared with Example 1, the Ag-Pr-Ag resonant cavity imaging structure in this embodiment enhances the light intensity distribution in the photoresist.

[0091] Figure 8 Schematic diagram of the normalized light intensity distribution at the center of the photoresist in the resonant cavity imaging structure. Figure 8 As shown in the figure, for the resonant cavity imaging structure, the electric field norm at the center of the photoresist decreases to a certain extent, and a certain degree of resonance occurs between the electric field and the light intensity distribution. Increasing the RMS roughness of the Ag film above and below the photoresist from 0.1nm to 0.7nm has no significant effect on the light intensity distribution at the center of the photoresist.

[0092] Figure 9 Schematic diagram of the curve of the light intensity contrast in the photoresist of the resonant cavity imaging structure and the surface roughness of the Ag layer. Figure 9 As shown, the surface roughness of the Ag layers on the upper and lower photoresist layers ranges from 0.1 nm to 0.7 nm, while the intensity contrast of the aerial image at the center of the photoresist remains above 0.98. Therefore, for the Ag-Pr-Ag imaging structure, a film roughness within the 0.7 nm range does not significantly affect the lithography quality, but its overall intensity contrast is higher than that of the Pr-Ag imaging structure in Example 1.

[0093] Example 3

[0094] The structure of the metal-dielectric unit in this embodiment is as follows Figure 10 As shown, the difference between this embodiment and embodiment 1 is:

[0095] In this embodiment, the structure of the metal-dielectric unit is an imaging structure in the form of photoresist-silver based on Ag-SiO2 multilayer film, such as Figure 10 The Ag-SiO2 multilayer film is composed of alternately arranged Ag layers 20 and silicon dioxide layers 10, specifically: a titanium dioxide flat layer 60, an Ag layer 20, a silicon dioxide layer 10, an Ag layer 20, a silicon dioxide layer 10 and an Ag layer 20 are sequentially arranged on the chromium strip 40.

[0096] The dielectric constant of titanium dioxide is 7.8375-0.2800i, the dielectric constant of multilayer Ag is -2.0525-0.73533i, and the dielectric constant of SiO2 is 2.1898-0.008838i. Other parameters remain the same as in Example 1.

[0097] Similarly, based on the finite element analysis method and combined with the wave function stray terms introduced by the surface roughness of the metal film layer, the Poynting vector distribution in the two-dimensional plane is obtained, as shown in Figure 11 Compared with Example 1, the imaging structure of the photoresist-silver form based on the Ag-SiO2 multilayer film in this embodiment is enhanced in the electromagnetic field energy during the propagation process due to the layer-by-layer coupling and superposition effect of the multilayer film on the evanescent wave.

[0098] Figure 12 Schematic diagram of the normalized light intensity distribution at the center of the photoresist in the resonant cavity imaging structure. Figure 12As shown in the figure, for a Ag-SiO2 multilayer resist-silver imaging structure, the RMS roughness of the Ag film increases from 0.1nm to 0.7nm. The evanescent wave spurious term, introduced through layer-by-layer accumulation and coupling, reaches the resist without causing a change in the spatial image intensity distribution at the center of the resist. This accumulation and coupling effect improves the Pr-Ag imaging structure's tolerance to film roughness, reducing its impact on lithography quality.

[0099] Figure 13 Schematic diagram of the curve of the light intensity contrast in the photoresist of the resonant cavity imaging structure and the surface roughness of the Ag layer. Figure 13 As shown in the figure, the film roughness increases from 0.1nm to 0.7nm, while the intensity contrast of the aerial image at the center of the photoresist remains above 0.992 and slightly below 0.993, with no change in the intensity contrast. Therefore, for Pr-Ag imaging structures, the impact of metal film roughness on the photoresist aerial image, and therefore the lithography quality, is due to the coupling and superposition of evanescent waves during the periodic transmission of the metal-dielectric unit, which improves the tolerance to metal film roughness.

[0100] The embodiments disclosed herein clearly show, through Examples 1 and 2, that the surface roughness of the metal film layer has a certain influence on the photolithography quality, and the photolithography quality of the Ag-Pr-Ag structure is better than that of the Pr-Ag structure. A metal Ag layer is introduced on the upper surface of the photoresist layer, and the Ag-Pr-Ag forms a reflective resonant cavity, which improves the light intensity distribution in the photoresist and the photolithography contrast. Since heavy metal Ag is introduced into the upper and lower layers of the photoresist, a more adaptable metal ion cleaning process is required to effectively clean and inspect the wafer after photolithography, which has solved the problem of heavy metal contamination of this imaging structure in the photolithography process. In addition, in combination with Example 3, it can be seen that for the mask-air-Pr-Ag structure of Example 1, a metal-dielectric multilayer film is introduced between the mask and the air, which reduces the influence of the film roughness on the photolithography quality.

[0101] It should be noted that the structure, single-layer film thickness, and materials of the metal-dielectric unit described in the above embodiments are merely exemplary and do not imply that the embodiments of the present disclosure are not applicable to metal-dielectric unit structures of other structures. Furthermore, the optimization method provided by the present disclosure is not limited to metal-dielectric unit structures in which the metal film layer is Ag. In other practical applications, it can also be used to optimize the roughness of other metal layers and dielectric layers.

[0102] In the actual photolithography process, the metal-dielectric unit structure of the actual requirements can be analyzed based on the optimization method provided by the present disclosure, and the photolithography quality in the photolithography process can be optimized, thereby reducing the line edge roughness of the photoresist pattern.

[0103] Figure 14 A block diagram of a device for optimizing lithography quality according to an embodiment of the present disclosure is schematically shown.

[0104] like Figure 14 As shown, the device for optimizing photolithography quality 1400 includes: a wave function stray term determination module 1410, a simulation module 1420 and a photolithography quality optimization module 1430. The device for optimizing photolithography quality 1400 can be used to implement reference Figure 1 A method for optimizing lithography quality is described.

[0105] The wave function stray term determination module 1410 is used to determine the wave function stray term introduced by the surface roughness of the metal film layer based on the characteristic matrix method and Bloch's theorem. According to the embodiment of the present disclosure, the wave function stray term determination module 1410 can be used to perform the above reference Figure 1 The described step S101 will not be repeated here.

[0106] The simulation module 1420 is used to input the wave function stray term into the mathematical model of the lithography quality deviation to perform calculation simulation, and obtain the influence analysis curve of the roughness of the metal film layer on the lithography quality. The influence analysis curve represents the influence result of the roughness of the metal film layer on the lithography quality. According to the embodiment of the present disclosure, the simulation module 1420 can be used to perform the above reference Figure 1 The above-mentioned step S102 will not be described in detail here.

[0107] The lithography quality optimization module 1430 is used to reduce the roughness of the metal film surface and / or set a metal-dielectric multilayer film structure between the mask and the air above the metal-dielectric unit according to the impact result, so as to optimize the lithography quality of the metal-dielectric unit. According to the embodiment of the present disclosure, the lithography quality optimization module 1430 can be used to perform the above reference Figure 1 The described step S103 will not be repeated here.

[0108] According to the modules, submodules, units, and subunits of the embodiments of the present invention, any multiple or at least part of the functions of any multiple thereof can be implemented in one module. According to the modules, submodules, units, and subunits of the embodiments of the present invention, any one or more thereof can be split into multiple modules for implementation. According to the modules, submodules, units, and subunits of the embodiments of the present invention, any one or more thereof can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware of any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation modes of software, hardware, and firmware or in an appropriate combination of any of them. Alternatively, according to the modules, submodules, units, and subunits of the embodiments of the present invention, one or more thereof can be at least partially implemented as a computer program module, which can perform the corresponding function when the computer program module is run.

[0109] For example, any multiple of the wave function stray term determination module 1410, the simulation module 1420, and the lithography quality optimization module 1430 can be combined into one module for implementation, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the wave function stray term determination module 1410, the simulation module 1420, and the lithography quality optimization module 1430 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or can be implemented in any one of the three implementation methods of software, hardware, and firmware, or in an appropriate combination of any of them. Alternatively, at least one of the wave function spurious term determination module 1410 , the simulation module 1420 and the lithography quality optimization module 1430 may be at least partially implemented as a computer program module, which may perform corresponding functions when executed.

[0110] Figure 15 The following schematically shows a block diagram of an electronic device suitable for implementing the method described above according to an embodiment of the present disclosure. Figure 15 The electronic device shown is only an example and should not limit the functions and scope of use of the embodiments of the present disclosure.

[0111] like Figure 15As shown, the electronic device 1500 described in this embodiment includes: a processor 1501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1502 or a program loaded from a storage part 1508 into a random access memory (RAM) 1503. The processor 1501 may, for example, include a general-purpose microprocessor (such as a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (such as an application-specific integrated circuit (ASIC)), etc. The processor 1501 may also include an onboard memory for caching purposes. The processor 1501 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0112] Various programs and data required for the operation of the electronic device 1500 are stored in the RAM 1503. The processor 1501, the ROM 1502, and the RAM 1503 are connected to each other via a bus 1504. The processor 1501 performs various operations of the method flow according to the embodiment of the present disclosure by executing the programs in the ROM 1502 and / or the RAM 1503. It should be noted that the programs may also be stored in one or more memories other than the ROM 1502 and the RAM 1503. The processor 1501 may also perform various operations of the method flow according to the embodiment of the present disclosure by executing the programs stored in the one or more memories.

[0113] According to an embodiment of the present disclosure, electronic device 1500 may further include an input / output (I / O) interface 1505, which is also connected to bus 1504. Electronic device 1500 may further include one or more of the following components connected to I / O interface 1505: an input portion 1506 including a keyboard, mouse, etc.; an output portion 1507 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), and speakers; a storage portion 1508 including a hard disk; and a communication portion 1509 including a network interface card such as a LAN card or a modem. Communication portion 1509 performs communication processing via a network such as the Internet. A drive 1510 is also connected to I / O interface 1505 as needed. Removable media 1511, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed in drive 1510 as needed, so that computer programs read from the removable media can be installed into storage portion 1508 as needed.

[0114] According to an embodiment of the present disclosure, the method flow according to an embodiment of the present disclosure can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable storage medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1509, and / or installed from the removable medium 1511. When the computer program is executed by the processor 1501, the above-mentioned functions defined in the system of the embodiment of the present disclosure are executed. According to an embodiment of the present disclosure, the system, equipment, device, module, unit, etc. described above can be implemented by a computer program module.

[0115] Embodiments of the present invention further provide a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments, or may exist independently and not incorporated into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method for optimizing lithography quality according to the embodiments of the present disclosure.

[0116] According to an embodiment of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In an embodiment of the present disclosure, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, apparatus, or device. For example, according to an embodiment of the present disclosure, the computer-readable storage medium may include the ROM 1502 and / or RAM 1503 described above and / or one or more memories other than ROM 1502 and RAM 1503.

[0117] The embodiments of the present disclosure also include a computer program product, which includes a computer program containing program code for executing the method shown in the flowchart. When the computer program product is executed in a computer system, the program code is used to enable the computer system to implement the method for optimizing lithography quality provided by the embodiments of the present disclosure.

[0118] The computer program executes the above functions defined in the system / device of the embodiment of the present disclosure when the computer program is executed by the processor 1501. According to the embodiment of the present disclosure, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0119] In one embodiment, the computer program may be stored on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may be transmitted and distributed in the form of a signal over a network medium, downloaded and installed via communication portion 1509, and / or installed from removable media 1511. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0120] In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 1509 and / or installed from the removable medium 1511. When the computer program is executed by the processor 1501, the above-described functions defined in the system of the embodiment of the present disclosure are performed. According to the embodiment of the present disclosure, the systems, devices, means, modules, units, etc. described above can be implemented by computer program modules.

[0121] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computer programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages include, but are not limited to, languages such as Java, C++, python, "C" or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect via the Internet).

[0122] It should be noted that the functional modules in the various embodiments of the present disclosure can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product.

[0123] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the above-mentioned module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0124] Those skilled in the art will appreciate that various combinations and / or combinations of features described in the various embodiments and / or claims of this disclosure may be made, even if such combinations or combinations are not explicitly described in this disclosure. In particular, various combinations and / or combinations of features described in the various embodiments and / or claims of this disclosure may be made, without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0125] Although the present disclosure has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made to the present disclosure without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above-described embodiments, but should be determined not only by the appended claims but also by the equivalents of the appended claims.

Claims

1. A method for optimizing photolithography quality, characterized in that: include: Based on the characteristic matrix method and Bloch's theorem, the stray terms of the wave function introduced by the surface roughness of the metal film are determined; Inputting the wave function stray term into a mathematical model of lithography quality deviation for calculation and simulation, thereby obtaining an analysis curve of the influence of the surface roughness of the metal film layer on the lithography quality, wherein the analysis curve represents the influence of the surface roughness of the metal film layer on the lithography quality; According to the impact result, the roughness of the metal film surface is reduced and / or a metal-dielectric multilayer film structure is provided between the mask and the air above the metal-dielectric unit to optimize the lithography quality of the metal-dielectric unit.

2. The method for optimizing lithography quality according to claim 1, wherein: The wave function stray terms introduced by the surface roughness of the metal film layer are determined based on the characteristic matrix method and Bloch's theorem, including: According to the characteristic matrix method, a characteristic matrix of the single-layer film in the metal-dielectric unit is obtained; Obtaining a unit characteristic matrix of the metal-dielectric unit according to the characteristic matrix of the single-layer film; Based on the Bloch theorem and the unit characteristic matrix, the variation term introduced by the film thickness caused by the surface roughness of the metal film layer is determined, and then the wave function stray term introduced by the surface roughness of the metal film layer is obtained.

3. The method for optimizing lithography quality according to claim 2, wherein: The characteristic matrix of the monolayer film The following relationship is satisfied: Among them, k x represents the wave vector of the evanescent wave along the x-axis, t n represents the thickness of the single layer film, k zn represents the wave vector of the electromagnetic wave along the z axis, k0 represents the wave vector in vacuum, ε0 represents the dielectric constant of vacuum, ε n Represents the dielectric constant of a single layer.

4. The method for optimizing lithography quality according to claim 3, wherein: The unit characteristic matrix of the metal-dielectric unit The following relationship is satisfied: Among them, t n =t m =t d , t m Indicates the thickness of the metal layer, t d represents the thickness of the dielectric layer, k zm represents the wave vector of the electromagnetic wave along the z axis in the metal layer, k zd represents the wave vector of the electromagnetic wave along the z axis in the dielectric layer, ε m is the dielectric constant of the metal layer.

5. The method for optimizing photolithography quality according to claim 4, wherein the wave function stray term introduced by the surface roughness of the metal film layer is The following relationship is satisfied: in, k z represents the wave vector of the evanescent wave along the z-axis, represents the normalized wave function of the transverse magnetic wave in the xz plane, Indicates the film thickness t caused by the surface roughness of the metal film layer m Introducing the variable term, z'=z+t m +t d , z represents the coordinate of the electromagnetic wave, and z' represents the coordinate of the electromagnetic wave passing through a metal-dielectric unit.

6. The method for optimizing photolithography quality according to claim 1, wherein: The wave function stray term is input into the mathematical model of lithography quality deviation for calculation and simulation, and an analysis curve of the influence of the surface roughness of the metal film layer on the lithography quality is obtained, including: The wave function stray terms are input into the mathematical model of lithography quality deviation for calculation and simulation to obtain the energy density distribution results of the metal-dielectric unit; According to the energy density distribution result, an analysis curve of the influence of the surface roughness of the metal film layer on the photolithography quality is obtained.

7. The method for optimizing photolithography quality according to claim 1, wherein: Before the step of determining the wave function stray term introduced by the surface roughness of the metal film layer, the method further comprises: Using an atomic force microscope to test the upper surface morphology of the metal film layer; The bottom surface morphology of the metal film layer is tested by using a template peeling and flipping technique; The surface roughness of the metal film layer is obtained according to the upper surface morphology and the lower surface morphology.

8. The method for optimizing photolithography quality according to claim 1, wherein: The metal-dielectric unit is composed of at least one metal film layer, and the dielectric layer in the metal-dielectric unit is located between the metal film layers.

9. The method for optimizing photolithography quality according to claim 8, wherein: The at least one metal film layer is composed of one or more materials selected from Ag, Al, and Au.

10. The method for optimizing photolithography quality according to claim 1, wherein: The metal-dielectric multilayer film structure is an Ag-SiO2 multilayer film structure.

11. A device for optimizing photolithography quality, characterized in that: include: A wave function stray term determination module is used to determine the wave function stray terms introduced by the surface roughness of the metal film layer based on the characteristic matrix method and Bloch's theorem; a simulation module, configured to input the wave function stray term into a mathematical model of lithography quality deviation for calculation and simulation, and obtain an analysis curve of the influence of the surface roughness of the metal film layer on the lithography quality, wherein the analysis curve represents the influence of the surface roughness of the metal film layer on the lithography quality; A photolithography quality optimization module is used to reduce the roughness of the surface of the metal film layer and / or set a metal-dielectric multilayer film structure between the mask plate and the air above the metal-dielectric unit according to the impact result, so as to optimize the photolithography quality of the metal-dielectric unit.

12. An electronic device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for optimizing lithography quality according to any one of claims 1 to 10 is implemented.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for optimizing lithography quality according to any one of claims 1 to 10 is implemented.

14. A computer program product comprising a computer program, wherein when the computer program is executed by a processor, the method for optimizing lithography quality according to any one of claims 1 to 10 is implemented.

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