A Simulation Analysis Method for Edge Accumulation / Filling Defects of Micro-Nano Gratings Based on Rsoft

Abstract

The present invention discloses a simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft. A first micro-nano grating model is built using Rsoft software, and parameter values are assigned to the first micro-nano grating model; an edge accumulation model is added to the grating layer of the first micro-nano grating model close to the grating groove, and a filling defect model is added to the grating groove to obtain a second micro-nano grating model; the width error parameter and height error parameter of the edge accumulation model and the width error parameter and depth error parameter of the filling defect model are respectively changed, and simulation analysis is carried out to obtain the spectral response curve of the second micro-nano grating model. The present invention can guide the design and analysis of micro-nano gratings, improve the success rate of micro-nano grating preparation, and reduce the preparation cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical imaging, and particularly relates to a simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft. Background Technique

[0002] As a new type of spectroscopic element, micro-nano gratings have received extensive attention due to their extremely small structural dimensions, high spectral resolution, high diffraction efficiency, and pixel-level spectroscopy. During the preparation process of micro-nano gratings, due to the influence of many technical factors such as raw materials and etching processes, defects such as over-etching, under-etching, and edge accumulation of the grating layer will occur, reducing the optical performance of micro-nano gratings. Therefore, establishing a defect analysis method for micro-nano gratings is particularly important for grating design and analysis.

[0003] Due to the limitations of micro-nano grating production and processing technologies, defects inevitably exist in the preparation process of micro-nano gratings, seriously affecting the optical performance of micro-nano gratings. Before the preparation of micro-nano gratings, it is extremely necessary to conduct error simulation analysis on the parameters of micro-nano gratings to guide the design of grating structures that are insensitive to errors, reduce the cost of grating preparation, and improve the actual optical performance of micro-nano gratings.

[0004] Currently, the main methods for discussing the structural parameters of micro-nano gratings include the beam propagation method, the finite-difference time-domain method, the finite element analysis method, etc. Software for micro-nano grating analysis includes FDTD Solutions, Rsoft, COMSOL Multiphysics, etc. Based on the clear expected optical performance of micro-nano gratings, designers obtain the initial grating structure parameters through certain calculations, then select a certain analysis software to further optimize the grating structure parameters, and finally obtain a set of optimal grating structure parameters. However, the optical performance exhibited by the micro-nano gratings prepared through the optimal structure parameters often has a large gap with the design values because designers only focus on different grating structure forms and the coupling of structure parameters during the design process, without considering the processing deviations in the design optimization. Summary of the Invention

[0005] The purpose of the present invention is to provide a simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft, analyze the influence of edge accumulation and filling defects of the grating layer widely existing in the processing and preparation of micro-nano gratings on the performance of micro-nano gratings, and guide the design and analysis of micro-nano gratings.

[0006] The present invention adopts the following technical solutions: A simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft, comprising the following steps:

[0007] Use Rsoft software to build a first micro-nano grating model and assign parameter values to the first micro-nano grating model;

[0008] An edge stacking model is added to the grating layer of the first micro-nano grating model near the grating groove, and a filling defect model is added to the grating groove to obtain a second micro-nano grating model;

[0009] Among them, the side of the edge stacking model close to the grating groove is a plane, and the side far from the grating groove is a stepped surface; the surface of the edge stacking model close to the side of the grating groove is a plane, and the surface far from the side of the grating groove is a stepped surface, and the plane of the edge stacking model fits the side surface of the grating groove;

[0010] The width error parameter and height error parameter of the edge stacking model and the width error parameter and depth error parameter of the filling defect model are respectively changed, and simulation analysis is carried out to obtain the spectral response curve of the second micro-nano grating model.

[0011] Furthermore, the edge stacking model and the filling defect model have the same shape.

[0012] Furthermore, the edge stacking model is stepped, the height of each step is equal, and the width of the upper step is smaller than the width of the lower step.

[0013] Furthermore, the width of the lower step is twice the width of the upper step.

[0014] Furthermore, filling defect models are added to both side surfaces of the grating groove, and the bottom surface of the filling defect model fits the bottom surface of the grating groove.

[0015] Furthermore, the plane of the edge stacking model and the side surface of the grating groove are in the same plane.

[0016] The beneficial effects of the present invention are as follows: By building the first micro-nano grating model in the Rsoft software and adding an edge stacking model and a filling defect model to the first micro-nano grating model, the processing deviation can be added to the micro-nano grating model, and then through the simulation analysis of the second grating model with the added processing deviation, the spectral response curve can be obtained, which can guide the design and analysis of the micro-nano grating, improve the preparation success rate of the micro-nano grating, and reduce the preparation cost. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the first micro-nano grating model in the embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of assigning parameter values to the first micro-nano grating model in the embodiment of the present invention;

[0019] Figure 3 It is a relatively typical partial cross-sectional view of the actual measurement and processing of the micro-nano grating in the embodiment of the present invention;

[0020] Figure 4Schematic diagram of the edge accumulation model in the embodiment of the present invention;

[0021] Figure 5 Schematic diagram of the second micro-nano grating model in the embodiment of the present invention;

[0022] Figure 6 Variation diagram of the micro-nano grating spectral response curve when the width error parameter of the edge accumulation model in the embodiment of the present invention gradually increases from 0.001 to 0.01;

[0023] Figure 7 is Figure 6 partial enlarged view of

[0024] Figure 8 Variation diagram of the micro-nano grating spectral response curve when the height error parameter of the edge accumulation model in the embodiment of the present invention gradually increases from 0.05 to 0.185;

[0025] Figure 9 Variation diagram of the micro-nano grating spectral response curve when the width error parameter of the filling defect model in the embodiment of the present invention gradually increases from 0.1 to 0.5;

[0026] Figure 10 Variation diagram of the micro-nano grating spectral response curve when the depth error parameter of the filling defect model in the embodiment of the present invention gradually increases from 0.02 to 0.065.

[0027] 1. First grating layer; 2. Second grating layer; 3. Third grating layer; 4. Grating groove; 5. Fourth grating layer. Specific embodiments

[0028] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The present invention discloses a simulation analysis method for micro-nano grating edge accumulation / filling defect based on Rsoft, including the following steps: building a first micro-nano grating model by using Rsoft software and assigning parameter values to the first micro-nano grating model; adding an edge accumulation model to the grating layer of the first micro-nano grating model close to the grating groove, and adding a filling defect model in the grating groove to obtain a second micro-nano grating model; wherein, the side of the edge accumulation model close to the grating groove is a plane, and the side away from the grating groove is a stepped surface; the side of the edge accumulation model close to the grating groove is a plane, and the side away from the grating groove is a stepped surface, and the plane of the edge accumulation model fits with the side surface of the grating groove; respectively changing the width error parameter, height error parameter of the edge accumulation model and the width error parameter, depth error parameter of the filling defect model, and performing simulation analysis to obtain the spectral response curve of the second micro-nano grating model.

[0030] In the present invention, by building a first micro-nano grating model in the Rsoft software and adding an edge accumulation model and a filling defect model to the first micro-nano grating model, processing deviations can be incorporated into the micro-nano grating model. Through simulation analysis of the second grating model with the incorporated processing deviations, a spectral response curve can be obtained, which can guide the design and analysis of micro-nano gratings, improve the success rate of micro-nano grating fabrication, and reduce the fabrication cost.

[0031] In one embodiment, the first micro-nano grating model is as Figure 1 shown, and it includes a first grating layer 1. There is a second grating layer 2 on the first grating layer 1. There are a third grating layer 3 and a fourth grating layer 5 on the second grating layer 2. Between the third grating layer 3 and the fourth grating layer 5 is a grating groove 4. As Figure 2 shown, it is an eigenvalue edit table built by the present invention using the Rsoft software, and the characteristic parameters included therein are: the thickness dodd of layer 1; the thickness dev of layer 2; the thicknesses of layers 3, 4, and 5 are equal, all being h; the period T of the micro-nano grating; the duty cycle f of the micro-nano grating.

[0032] As Figure 2 shown, in the eigenvalue edit table, the eigenvalues can be edited. In this embodiment, it is set that dodd = 1.33; dev = 1.37; h = 0.605; T = 0.1; f = 0.5. Layers 1-5 are all created using the Segment(In Plane) tool in the Rsoft software. The widths of layers 1 and 2 are set to 2.5*T; the widths of layers 3 and 5 are set to f*T; the width of layer 4 is set to (1 - f)*T. Building the micro-nano grating model is the basis for the inventor to analyze various defects.

[0033] In one embodiment, the edge accumulation model and the filling defect model have the same shape. The edge accumulation model is in a stepped shape, and the height of each step is equal, and the width of the upper step is smaller than the width of the lower step. The width of the lower step is twice the width of the upper step.

[0034] Moreover, filling defect models are added to both side surfaces of the grating groove, and the bottom surface of the filling defect model fits the bottom surface of the grating groove. The plane of the edge accumulation model and the side surface of the grating groove are in the same plane.

[0035] As Figure 3As shown in the figure, a relatively typical partial cross-sectional view of the measured processing of a micro-nano grating is shown. It can be seen from the figure that there is a certain stacking phenomenon at the edge of the grating layer of the micro-nano grating, and there are incomplete filling defects in the grating grooves. Furthermore, through statistical analysis of a certain number of cross-sectional views, the results show that the edge stacking and filling defects of the grating layer present a stepped shape. Therefore, in this embodiment, the width error parameter det1, height error parameter h1 of the edge stacking model, width error parameter det2, and depth error parameter h2 of the filling defect model are introduced.

[0036] As Figure 4 shown, the model building method of the edge stacking phenomenon of the grating layer in the Rsoft software is shown. Furthermore, in this embodiment, a structure with a decreasing width of 3 layers of orders is used to simulate the edge stacking of the grating layer, and the characteristic parameters det1 and h1 are respectively used to control the edge stacking width and height. Similarly, the filling defect model uses the characteristic parameters det2 and h2 to control the severity of the filling defect. Figure 5 is a partial enlarged view of the grating layer area by introducing the measured processing error size into the micro-nano grating model. It can be seen from the figure that the stepped structure well reproduces the edge stacking and filling defect phenomena widely existing in the actual processing of micro-nano gratings.

[0037] In the Launch MOST Optimizer / Scanner module of the Rosft software, set Variable to det1, Type to Fixed inc, Low value to 0.001, High value to 0.01, and Incr. value to 0.001 for simulation analysis. Figure 6 It reflects the change of the spectral response curve of the micro-nano grating when the edge stacking width of the grating layer gradually increases from 0.001 to 0.01 (for clearer display, only the spectral response curves when det1 = 0.001, 0.003, 0.005, 0.007, 0.01 are shown in this figure). It can be seen from the figure that the overall line type of the spectral response of the micro-nano grating remains basically unchanged (that is, the central wavelength and peak half-width fluctuate within a small range, which indicates that the edge stacking defects existing in the processing of micro-nano gratings do not change the main characteristics (band-pass or band-stop) of the micro-nano grating. In addition, as Figure 7 shown, it can be concluded from the partial enlarged view that as the edge stacking width increases, the central wavelength position of the spectral response curve of the micro-nano grating undergoes a red shift, the bandwidth decreases, the peak increases, and the spectral response curve tends to become "higher and thinner".

[0038] In the Launch MOST Optimizer / Scanner module of Rosft software, set Variable to h1, Type to Fixed inc, Low value to 0.05, High value to 0.185, and Incr. value to 0.015, and perform simulation analysis. Figure 8 It reflects the change of the spectral response curve of the micro-nano grating when the edge stacking height of the grating layer gradually increases from 0.05 to 0.185 (for clearer display, only the spectral response curves at h1 = 0.05, 0.08, 0.11, 0.14, and 0.185 are shown in this figure). It can be seen from the figure that the overall line type of the spectral response of the micro-nano grating remains basically unchanged. However, as the edge stacking height increases, the central wavelength of the spectral response curve of the micro-nano grating shifts towards shorter wavelengths, the bandwidth increases, the peak value decreases, and the spectral response curve tends to become "shorter and fatter".

[0039] In the Launch MOST Optimizer / Scanner module of Rosft software, set Variable to det2, Type to Fixed inc, Low value to 0.1, High value to 0.5, and Incr. value to 0.05, and perform simulation analysis. Figure 9 It reflects the change of the spectral response curve of the micro-nano grating when the filling defect width gradually increases from 0.1 to 0.5 (for clearer display, only the spectral response curves at det2 = 0.1, 0.25, 0.35, and 0.5 are shown in this figure). It can be seen from the figure that as the filling defect width increases, the peak diffraction efficiency of the spectral response drops sharply, but the position of the central wavelength does not change. This shows that the filling effect of the grating layer directly affects the spectral splitting signal-to-noise ratio of the micro-nano grating and is an important factor affecting the preparation qualification rate of the micro-nano grating.

[0040] In the Launch MOST Optimizer / Scanner module of Rosft software, set Variable to h2, Type to Fixed inc, Low value to 0.02, High value to 0.065, and Incr. value to 0.005, and perform simulation analysis. Figure 10It reflects the change of the spectral response curve of the micro-nano grating when the filling defect depth gradually increases from 0.02 to 0.065 (for clearer display, only the spectral response curves at h2 = 0.02, 0.035, 0.045, 0.055, and 0.065 are shown in this figure). It can be seen from the figure that as the filling defect depth increases, the line type of the spectral response curve changes, the center wavelength position jumps, and the peak diffraction efficiency drops sharply. This shows that when there is a filling depth defect in the grating layer, the basic spectral splitting ability of the micro-nano grating will be damaged, and when the filling depth defect is large, it will directly lead to the failure of the micro-nano grating to split light.

[0041] The present invention provides a stepped model based on the Rsoft software for the edge accumulation / filling defect phenomenon that occurs during the processing of micro-nano gratings. This will inspire other designers in the field. For various deviations in micro-nano processing, models including but not limited to stepped, quadratic curve, polynomial models, etc. can be used to simulate and reproduce the processing errors, and then more accurately analyze the actual spectral response of micro-nano gratings.

[0042] In the embodiment of the present invention, the influence results of four defect parameters, namely the edge accumulation width det1, the edge accumulation height h1, the filling defect width det2, and the filling defect depth h2, on the spectral response of the micro-nano grating are analyzed. The results show that det1 and h1 will not have a huge impact on the overall line type of the spectral response of the micro-nano grating, but will shift the center wavelength position of the spectral response curve to a certain extent. This means that in the field where the center wavelength position of the grating is required to be accurate, the occurrence of edge accumulation defects should be strictly controlled; while the increase of det2 will directly reduce the peak diffraction efficiency of the spectral response, and then reduce the signal-to-noise ratio of the micro-nano grating splitting light. The increase of h2 will directly affect the line type of the spectral response (center wavelength position, sideband energy, etc.). This means that the occurrence of filling defects should be avoided as much as possible during the actual processing of micro-nano gratings.

Claims

1. A simulation and analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft, characterized in that Including the following steps: Build a first micro-nano grating model using Rsoft software and assign parameter values to the first micro-nano grating model; Add an edge accumulation model to the grating layer of the first micro-nano grating model close to the grating groove, and add a filling defect model in the grating groove to obtain a second micro-nano grating model; Wherein, the side surface of the edge accumulation model close to the grating groove is a plane, and the side surface away from the grating groove is a stepped surface; the surface of the edge accumulation model close to the side surface of the grating groove is a plane, and the surface away from the side surface of the grating groove is a stepped surface, and the plane of the edge accumulation model fits the side surface of the grating groove; Respectively transform the width error parameter and height error parameter of the edge accumulation model and the width error parameter and depth error parameter of the filling defect model, and perform simulation analysis to obtain the spectral response curve of the second micro-nano grating model.

2. The simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft according to claim 1, wherein The edge accumulation model has the same shape as the filling defect model.

3. The simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft according to claim 2, wherein The edge accumulation model is in a stepped shape, the height of each step is equal, and the width of the upper step is smaller than the width of the lower step.

4. The simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft according to claim 3, wherein The width of the lower step is twice the width of the upper step.

5. A simulation analysis method for micro-nano grating edge accumulation / filling defects based on Rsoft according to any one of claims 2-4, characterized in that, Add the filling defect model to both side surfaces of the grating groove, and the bottom surface of the filling defect model fits the bottom surface of the grating groove.

6. The simulation analysis method for edge accumulation / filling defects of micro-nano gratings based on Rsoft according to claim 5, characterized in that, The plane of the edge accumulation model and the side surface of the grating groove are in the same plane.

Images