A simulation method for evolution of blaze grating etching profile

Abstract

This invention provides a method for simulating the morphological evolution of blazed grating etching, including: pre-constructing an etching mask structure based on a pre-defined blazed grating structure; determining etching contour lines at different times and positions based on the morphological evolution of the mask structure during etching, and determining the motion properties of different contour lines; determining the linear equation of each contour line and the motion mode of each contour line; determining the motion direction of each contour line in combination with different etching processes; and determining and updating the position and linear equation of each contour line at different etching times based on the motion direction and motion rate of each contour line; and judging the simulated etching endpoint of the blazed grating etching morphology based on different etching processes. This invention can more accurately describe the influence of different processes and process parameters on the final etching result, perform in-depth processing of discrete technical data, and thus predict and control the ion beam etching process.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for simulating the evolution of blazed grating etching morphology. Background Technology

[0002] Blazed gratings, as key optical components, have wide applications in various fields due to their unique spectral dispersion and filtering capabilities. These fields include smart glasses (such as virtual reality (VR) and augmented reality (AR) glasses), monochromators, precision measurement, laser shaping, display technology, and optical communication. The zero-order spectral dispersion properties of blazed gratings make them indispensable in these technologies.

[0003] Traditional large-scale blazed gratings (micrometers and above) are primarily fabricated using mechanical scribing and holographic ion beam etching, while submicron-period blazed gratings require electron beam lithography. Submicron-period blazed gratings demand extremely high fabrication precision, with periods less than 500 nanometers, blaze angle curvature radii less than 10 nanometers, and require grayscale exposure. The blaze angle evolution is significant, and the photoresist-to-substrate etching selectivity ratio must be controlled at 1:1. This makes the electron beam exposure and etching processes extremely demanding and challenging, and currently, there is no stable and reliable fabrication method.

[0004] Existing methods for fabricating blazed gratings, especially submicron blazed gratings, face numerous challenges. For example, the photoresist mask is difficult to control in traditional holographic ion beam etching, making it difficult to precisely control the morphology of the blazed grating. Furthermore, submicron periodic blazed gratings place extremely high demands on electron beam exposure and etching processes, increasing the complexity and difficulty of fabrication. The fabrication of parameters such as tooth shape, depth, duty cycle, and period of diffraction gratings requires stable and mature process technology capabilities. Typically, fabricating diffraction gratings with the designed parameters often requires extensive debugging and repeated verification of equipment process parameters until a stable result is output. When multiple design parameters need to be achieved, the workload of such process parameter debugging and verification undoubtedly increases exponentially, resulting in high time and labor costs. However, this is not enough; the process data obtained in this way is often discrete, and the technological barrier is extremely low, failing to form a significant technological barrier within the industry.

[0005] To improve the fabrication precision and efficiency of blazed gratings, developing a simulation method for the evolution of blazed grating etching morphology is crucial. Through simulation, discrete technical data can be processed in depth to construct a systematic process database with predictive capabilities. This allows for the prediction and control of the ion beam etching process, optimization of process parameters, and ultimately, improvement of the performance and quality of the blazed grating. This is of particular importance to those skilled in the art. Summary of the Invention

[0006] This invention provides a simulation method for the morphological evolution of blazed gratings during etching, overcoming the limitations of existing technologies and improving the fabrication accuracy and efficiency of blazed gratings. The simulation method provided by this invention can more accurately describe the influence of different processes and parameters on the final etching result, perform in-depth processing of discrete technical data, and thus predict and control the ion beam etching process, providing a new technical approach for the fabrication of blazed gratings.

[0007] This invention provides a method for simulating the evolution of scintillation morphology in blazed gratings, comprising the following steps:

[0008] Step (1): Based on the pre-defined blazed structure of the blazed grating, an etching mask structure is pre-constructed;

[0009] Step (2): Based on the morphological evolution of the mask structure during the etching process, determine the etching contour lines at different times and positions, and determine the motion properties of different contour lines.

[0010] Step (3): Based on the motion attributes of different contour lines, determine the straight line equation of each contour line and the motion mode of each contour line;

[0011] Step (4): Based on the motion mode of each contour line determined in step (3), and in combination with different etching processes, determine the motion direction of each contour line; and based on the motion direction and motion rate of each contour line, determine and update the position and straight line equation of each contour line under different etching times.

[0012] Step (5): Determine the simulated etching endpoint of the blazed grating etching morphology based on different etching processes; when the etching endpoint is reached, the simulation of the blazed grating etching morphology is completed.

[0013] Furthermore, in step (2), in detail, the contour lines of the etching shape at different positions of the mask structure during the etching process are determined based on the evolution of the etching morphology of the mask structure at different times and positions during the etching process.

[0014] Furthermore, during the etching process and before reaching the etching endpoint, the mask structure includes a first contour line, a second contour line, a third contour line, a fourth contour line, and a fifth contour line connected in sequence within one mask cycle; and based on the evolution of the etching morphology of the mask structure during the etching process, the attributes of the two endpoints of each contour line are determined to determine the motion attributes of each contour line.

[0015] In some embodiments, specifically, the first contour line includes a fixed node and an active node arranged in sequence, the fixed nodes maintaining different positions, and the active node driving the contour line to evolve with the increasing etching depth; the second contour line includes two active nodes, which drive the contour line to evolve with the increasing etching depth; the third contour line includes one active node and one passive node arranged in sequence, the active node driving the passive node to achieve the contour line evolution with the increasing etching depth; the fourth contour line includes two... The passive node is a contour line formed by two passive nodes, which evolves as the etching depth increases. The fifth contour line includes passive nodes and fixed nodes arranged in sequence, forming the contour line and evolving as the etching depth increases. Each active node, passive node, and fixed node is arranged in sequence along the direction of light propagation in the blazed grating or the opposite direction of propagation, and each active node, passive node, and fixed node defines the motion properties of each contour line.

[0016] In some other embodiments, in step (3), based on the motion properties of the different contour lines, the equation of the straight line for each contour line is determined, specifically based on the formula: The equation of the line for each contour line is determined to determine the trajectory of each contour line. (x1, y1) and (x2, y2) represent the position coordinates of any two points on a certain contour line of the mask structure, and (x, y) represent the equation of the line for the contour line. Based on the different motion attributes of different contour lines and the motion rate of different contour lines, the motion mode of different contour lines is determined.

[0017] In detail, the motion mode of different contour lines is determined, including along the ion beam etching direction, the motion mode is obtained based on the etching rate at different positions and the etching direction determined by the mask structure.

[0018] In some embodiments, in step (4), the position and straight line equation of each contour line under different etching times are determined and updated. Specifically, under different etching times, the starting point and ending point of the new line segment of the contour line are reconstructed at the intersection of the contour lines at different positions. Based on the movement direction and movement speed of each contour line, the position and straight line equation of each contour line under different etching times are determined and updated, and the movement path of each contour line is replanned.

[0019] In detail, in some other embodiments, in step (5), the simulated etching endpoint of the blazed grating etching morphology is determined based on different etching processes, including determining that the etching endpoint has been reached when the line segment length of the fifth contour line is less than a certain threshold.

[0020] In some other embodiments, in step (5), the simulated etching endpoint of the blazed grating etching morphology is determined based on different etching processes, including stopping etching when the two endpoints of the fifth contour line coincide.

[0021] Optionally, in some other embodiments, in step (5), the simulated etching endpoint of the blazed grating etching morphology is determined based on different etching processes. This includes determining that the etching endpoint is reached when, within any two adjacent mask cycles of the mask structure, the active node of the first contour line coincides with the fixed node of the fifth contour line in its adjacent cycle.

[0022] In the simulation process of this invention, based on the relative relationship between the blaze angle of the blazed grating and the tilting etching of the ion beam, a quantitative relationship is established between the evolution of the contour lines at different positions of the mask structure and the etching movement rate. This allows for real-time updates and optimizations of the position of the contour lines of each mask structure and the corresponding linear equations at different etching times. This invention redefines the edges and points of all contours during the etching process and "independently" processes the edges and points of the contour lines. Based on discrete technical data, it performs in-depth processing to predict and control the ion beam etching process. Combined with the actual etching rate, this achieves a more accurate prediction and determination of the evolution trend of the etched structure contours, resulting in a more systematic and convenient simulation process.

[0023] Experimental verification shows that the proposed simulation equations can accurately describe the influence of different processes and parameters on the final etching result, with simulation errors controlled within 5% and etching cutoff point errors controlled within 1%. This indicates that the simulation method can effectively predict and control the ion beam etching process, which has significant practical application value for the fabrication of blazed gratings. Furthermore, it can theoretically retrospectively analyze and judge defects in the blazed structure after etching, providing theoretical guidance and experimental support for the analysis of etching intermediate states of blazed gratings; demonstrating unexpected technical effects and significant progress. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of a mask structure for a certain blazed grating structure provided by the present invention;

[0026] Figures 2-5 The present invention provides the etching morphology evolution of a mask structure at different times and positions under the etching action of an ion beam.

[0027] Figure 6 This is a schematic diagram of a blazed grating structure provided by the present invention;

[0028] Figure 7 This is a schematic diagram illustrating the intermediate etching evolution process of the mask structure during etching morphology simulation of the blazed grating provided by the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] This invention provides a simulation method for the evolution of blazed grating etching morphology, overcoming the limitations of existing technologies and improving the fabrication accuracy and efficiency of blazed gratings. The simulation method provided by this invention can more accurately describe the influence of different processes and parameters on the etching morphology. By performing in-depth processing of discrete technical data, the ion beam etching process can be predicted and controlled, providing a new technical approach for the fabrication of blazed gratings.

[0032] In detail, a simulation method for the morphological evolution of blazed grating etching, such as... Figure 1 The process, as shown in the diagram, includes the following steps:

[0033] Step (1): Based on the pre-defined blazed structure of the blazed grating, an etching mask structure is pre-constructed;

[0034] In step (1), specifically, based on the blaze structure characteristic parameters of the preset blaze grating, an etching mask structure is constructed, and the blaze structure is etched based on this mask structure; the blaze structure design parameters include characteristic parameters such as blaze angle, anti-blaze angle, period, aspect ratio, and blaze height. Figure 1 As shown, a mask structure is constructed based on the blazing structure, and the etching results of the mask structure match the parameters of the blazing structure. More specifically, the mask structure includes several periodic structures... Figure 1 In this context, within a period T of several periodic structures, the mask structure has a defined contour structure, such as... Figure 1 The dashed line shows the mask structure within one period T. For example, in one embodiment, based on the desired final blazed structure, a trapezoidal tooth with an upper tooth width of 160 nm, a lower tooth width of 200 nm, a period of 400 nm, and a tooth height of 200 nm is selected as one type of mask structure. Of course, different blazed grating structures require different etching mask structures, which is clearly understood.

[0035] Step (2) Based on the morphological evolution of the mask structure during the etching process, the etching contour lines at different times and positions are determined, and the motion properties of different contour lines are determined.

[0036] In detail, such as Figure 2 As shown in the figure, the arrows indicate the etching direction of the ion beam. The figure illustrates the evolution of the etching morphology of the mask structure at different times and locations during the etching process under the ion beam etching effect. A more detailed and continuous illustration of the etching process evolution is shown below. Figure 4 and Figure 5 As shown, under this trend, etching continues; in this process, the contour lines of the etching shape at different positions of the mask structure are determined. The contour line refers to the structural outline of the mask structure as the etching morphology evolves at different times and positions. Continuous etching is performed along this contour line to form the predetermined scintillation structure; such as... Figure 3 The diagram illustrates the outline of the mask structure at a specific moment and location within a single mask structure cycle. Within one cycle of the mask structure etching process, five outlines are included: the first outline, the second outline, the third outline, the fourth outline, and the fifth outline. It can be understood that within any cycle after etching begins but before it is completed, there are five outlines of the mask structure. Figure 1 As shown, before etching, one mask structure cycle includes four contour lines. Figure 4 As shown, after etching is completed, there are two outline lines.

[0037] Furthermore, determine the motion properties of each contour line within any given period. In detail, such as... Figure 3 As shown, within one mask structure cycle T after etching begins but before etching is completed, there are 5 contour lines. Based on the evolution of the morphology of the mask structure during the etching process, the properties of the two endpoints of each contour line are determined to determine the motion properties of each contour line. Furthermore, for the first contour line, including endpoints A1 and A2, based on the evolution of the mask structure contour line during etching, A1 is defined as a fixed node and A2 as an active node. That is, the first contour line includes fixed nodes and active nodes set in sequence. During etching, endpoint A1 of the first contour line remains in a fixed position, while A2 drives the evolution of the first contour line to simulate the evolution of the etching morphology. In other words, the fixed nodes remain in different positions, and the active nodes drive the contour line to evolve with the increasing etching depth. Furthermore, for the second contour line, including endpoints A2 and B1, B1 is defined as an active node. That is, the second contour line includes two active nodes set in sequence, meaning that the two active nodes drive the contour line to evolve with the increasing etching depth. For the third contour line… The third contour line includes endpoints B1 and B2, with B2 defined as a passive node. This means the third contour line consists of one active node and one passive node arranged sequentially. The active node drives the passive node, causing the contour line to evolve with increasing etching depth. The fourth contour line includes endpoints B2 and C1, with C1 defined as a passive node. This means the fourth contour line consists of two passive nodes arranged sequentially, forming a contour line that evolves with increasing etching depth. The fifth contour line includes endpoints C1 and C2, with C2 defined as a fixed node. This means the fifth contour line consists of two passive and fixed nodes arranged sequentially, forming a contour line that evolves with increasing etching depth.

[0038] Furthermore, the first, second, third, fourth, and fifth contour lines are sequentially connected and set. Each contour line is formed and defined based on the contour structure of the mask structure, and the sequential connection of each contour line forms the contour structure of the mask structure. The first contour line is sequentially set with fixed nodes and active nodes, the second contour line includes two active nodes, the third contour line is sequentially set with active nodes and passive nodes, the fourth contour line includes two passive nodes, and the fifth contour line includes passive nodes and fixed nodes. Each node is sequentially set along the direction of light propagation in the blazed grating or the opposite direction of propagation to form a continuous structural contour.

[0039] It also includes: defining a contour line segment as a fixed line segment when both its left and right endpoints contain at least one fixed node; defining a contour line segment as a passive line segment when both its left and right endpoints are passive nodes; and defining line segments other than fixed and passive line segments as active line segments.

[0040] To further explain, the fixed node defined in this invention refers to a node whose etching depth or height does not evolve with etching time during the etching simulation process; the fixed node remains in a fixed position. An active node refers to a node whose etching depth or height evolves with etching time and is preferentially etched during the etching process, meaning its position actively evolves due to preferential etching. A passive node refers to a node whose etching depth or height evolves with etching time and its etching position passively evolves under the influence of the active node during the etching process. In conjunction with the foregoing, the mask structure's contour includes five contour lines, and these five contour lines define five attribute points: a fixed node, an active node, a passive node, a passive node, and a fixed node. The motion attributes of each contour line are defined based on these five attribute points; that is, each node defines the motion attributes of each contour line, which can include fixed segments, passive segments, and active segments, each with different motion attributes. In this invention, the first contour line is a fixed line segment, the second and third contour lines are active line segments, the fourth contour line is a passive line segment, and the fifth contour line is a fixed line segment.

[0041] It is known that the endpoints of each of the first, second, third, fourth, and fifth contour lines are connected sequentially to form a continuous mask contour within one cycle.

[0042] In some embodiments, the method further includes step (3), which involves determining the linear equation of each contour line based on the motion properties of different contour lines, and determining the motion mode of each contour line.

[0043] In detail, the etching process leads to the evolution of the mask morphology, which is mainly constructed through multiple contour lines, characterized by straight lines. Figures 1-3 As shown. Therefore, the evolution of the etching morphology is reflected in the movement of straight lines. In order to describe the evolution of the etching morphology, we first need to define and determine the straight line equation of each contour line.

[0044] Based on the line segment equation: ax + by = c, where x and y represent the coordinates of a straight line in the contour line, respectively the horizontal and vertical coordinates; a, b, and c represent coefficients. To accurately describe the etching morphology at each moment, we need to obtain the equations of a series of moving straight lines to determine positional information. Therefore, we must first obtain the parameter information of the straight line equations: a, b, and c. More specifically, based on the positions of any two points on each contour line, such as A(x1, y1) and B(x2, y2), the coefficients of a, b, and c in ax + by = c are determined based on these two points, as shown in Formula 1 below:

[0045]

[0046] After transformation, we get: (y2-y1)x+(x1-x2)y+y1(x2-x1)-(y2-y1)x1=0(2)

[0047] We can obtain a = y2 - y1, b = x1 - x2, c = (y2 - y1)x1 - y1(x2 - x1)(3)

[0048] Based on the above relationships, the equation of the straight line for each contour line is determined, thereby determining the motion trajectory of each contour line. This motion trajectory represents the evolution of the etching morphology at different locations and at different etching times.

[0049] Simultaneously, after determining the line segment equations of each contour line, the motion mode of each contour line is further determined. Based on the motion attributes of different contour lines determined in step (2), and the straight line equations of different contour lines, a contour line with at least one fixed node at both its left and right endpoints is defined as a fixed line segment; a contour line with both its left and right endpoints being passive nodes is defined as a passive line segment; and other line segments besides fixed and passive line segments are defined as active line segments. The motion rates of fixed, passive, and active line segments are determined respectively, and the motion mode of each contour line is determined. The motion mode of different contour lines is determined by the motion rates of different contour line segments. This includes the etching direction along the ion beam etching direction, determined based on the etching rate at different positions and the mask structure.

[0050] The motion rates of fixed line segments, passive line segments, and active line segments are determined based on the intermediate processes and related etching parameters of multiple blazed grating etching processes according to this invention. In this regard, based on existing etching processes, it is possible to determine the rate of each line segment at different positions.

[0051] In detail, the movement rate of the fixed line segment and the active line segment can be determined based on the etching process; for the movement rate of the passive line segment, it is reconstructed and calculated based on the different etching times, the new movement point and the new passive line segment, and the linear equation of the passive line segment at each time point is recalculated based on the coordinates of the known point. This process is continuously reconstructed to achieve continuous updating and iteration of the passive line segment, thereby simulating the etching morphology of different regions and obtaining the movement mode of the passive line segment.

[0052] It also includes step (4), which determines the direction of motion of each contour line based on the motion mode of each contour line determined in step (3) and in combination with different etching processes; and determines and updates the position and straight line equation of each contour line under different etching times based on the direction and speed of motion of each contour line.

[0053] In this step, the motion direction of each contour line is determined according to the actual etching process requirements based on the line segment equation and motion mode of each contour line determined in step (3) for the next etching step. During the etching process, the different contour lines are adjusted and updated in real time based on the motion direction and motion speed of each contour line, and the position and straight line equation at different times are used to accurately simulate the etching situation in the real etching environment in real time.

[0054] During the etching morphology simulation, the position and straight line equation of each contour line are different with different movement and etching time. In order to accurately simulate the etching process of the blazed grating, the starting point and ending point of the new line segment are reconstructed at the intersection of the five contour lines at different positions under different etching time. Combined with the movement direction and speed of each contour line, the position and straight line equation of each contour line under different etching time are determined and updated, and the movement path is replanned to achieve real-time dynamic adjustment of each contour line.

[0055] like Figure 4 As shown, the etching evolution process of five contour lines in the mask structure at different positions and times is illustrated within one mask cycle of the mask structure at different etching times. The line equations and directions of motion of the five contour lines are different at different times and positions. Based on this, the line equations of different line segments are updated in real time to improve the accuracy of the simulation.

[0056] Further integration Figure 5 Based on the method of this invention, the etching evolution process of five contour lines in a mask structure at different positions and times during two adjacent cycles of the mask structure at different etching times is shown, thereby forming a blazed grating structure with multiple periods. Of course, Figure 4 and Figure 5This is merely a schematic diagram of the blazing structure formed during the simulation of blazing etching morphology, and does not constitute a limitation on the blazing structure. It is known that different blazing grating structures are formed based on different preset blazing structures, different mask structures, different directions of motion of contour lines and different equations of line segments.

[0057] Furthermore, it also includes step (5), which determines the simulated etching endpoint of the blazed grating etching morphology based on different etching processes; when the etching endpoint is reached, the simulation of the blazed grating etching morphology is completed.

[0058] It is known that in the fabrication of a blazed grating structure, there exists a unique and optimal etching stop point, which is determined by the mask structure. The etching is completed primarily when the mask has completely disappeared. For example... Figure 4 As shown, Figure 4 The shaded area shows the scintillation structure formed at the end of the etching process.

[0059] The simulated etching endpoint for determining the etching morphology of blazed gratings based on different etching processes is detailed, including different methods.

[0060] In some embodiments, such as method one, combined Figure 3 As shown, when the length of the fifth contour line segment is less than a certain threshold, it is determined that the etching endpoint has been reached, and the etching is stopped. For example, if the length of the fifth contour line segment is less than the range of (10, 20) nm, the etching is stopped. The specific value of the threshold is determined based on the etching process, etching material, and blazed grating structure.

[0061] In some embodiments, such as Method 2, the etching process is further improved by stopping the etching when the two endpoints of the fifth contour line coincide. The computer program determines whether the two endpoints coincide. When the two endpoints coincide, the etching process is complete, and the desired blazed grating structure is formed.

[0062] In some embodiments, such as Method 3, when the active node of the first contour line coincides with the fixed node of the fifth contour line in any two adjacent mask cycles, the etching endpoint is reached at this moment. During the etching morphology simulation, it is determined whether the active node of the first contour line coincides with the fixed node of the adjacent fifth contour line in two adjacent mask cycles, thereby calculating the etching endpoint under different mask structures.

[0063] This process also includes determining etching process parameters such as the etching tip angle and etching time.

[0064] Through the above steps (1) to (5), the simulation process of the blazed grating etching morphology is completed. During the simulation, based on the relative relationship between the blazed grating blaze angle and the ion beam tilt etching, a quantitative relationship between the evolution of the mask structure contour and the etching movement rate is established to update the position and linear equation of each contour at different etching times in real time. This invention redefines the edges and points of all contours during the etching process and "independentizes" the edges and points of the contours. Combined with the actual etching rate, it achieves a more accurate prediction and determination of the movement trend of the etched structure contour, realizing a more systematic and convenient simulation process.

[0065] Further integration Figure 6 As shown, a blazed grating structure is illustrated. Based on the simulation method for the evolution of blazed grating etching morphology provided by this invention, it is possible to achieve, as shown in the figure, a blazed grating structure. Figure 6 The etching morphology simulation of the grating structure shown includes the simulation of the etching intermediate state; the scintillation structure formed by the etching morphology simulation method can match the actual scintillation structure, and the two can be well verified against each other.

[0066] In some other embodiments, the invention also includes, as Figure 7 As shown, Figure 7 The left-middle figure illustrates the intermediate etching evolution process of the mask structure during blazed grating etching morphology simulation. Based on this process, the simulation results of the intermediate state and the actual etching SEM results were compared and analyzed. With a fixed ion beam direction, the line segments contained in the simulated intermediate state contour were numbered ① to ⑤. Simultaneously, the intermediate state of the actual blazed etched sample was characterized by SEM analysis of a cleaved section, and the line segments contained in its contour were also numbered. The results show that the evolution process obtained by the simulation method is consistent with the actual etching process, as shown by line segments ① to ⑤ in the figure; all five line segments correspond in both the simulation and actual etching processes. Figure 7 As shown in the middle right figure, the intermediate etching evolution process of the mask structure in the simulation corresponds to the etching evolution process of the mask structure in the actual etching process, including... Figure 7 The etching "plateau" problem that occurs in the mask structure shown in the figure can be well matched and "verified" in the actual etching process, indicating that the simulation method can truly reproduce the etching process and explain the etching problems existing in the prior art.

[0067] By comparing and analyzing the simulation results of the etching intermediate state with the actual etching SEM results, it can be found that the simulation results and the actual etching results are in good agreement.

[0068] Experimental verification shows that the proposed simulation method can accurately describe the influence of different processes and parameters on the final etching result, with simulation errors controlled within 5% and etching cutoff point errors controlled within 1%. This indicates that the simulation method can effectively predict and control the ion beam etching process, and has significant practical application value for the fabrication of blazed gratings.

[0069] In practice, the present invention provides a simulation method for the etching morphology evolution of a blazed grating, which can simulate the etching process based on the structure of the blazed grating. Based on the simulation method, a systematic process database with predictive capabilities is constructed, which can better predict and control the ion beam etching process, optimize process parameters, and thus improve the performance and quality of the blazed grating.

[0070] The simulation method of this invention can more accurately describe the influence of different processes and process parameters on the final etching result, perform in-depth processing on discrete technical data, and thus predict and control the ion beam etching process, providing a new technical approach for the fabrication of blazed gratings.

[0071] Based on the simulation method of this invention, the scintillation process and final morphology can be predicted by setting mask structures with different periods, aspect ratios, and heights. At the same time, based on the preset scintillation morphology, the period, aspect ratio, and height of the grating structure can be selected to achieve reverse inference. Furthermore, based on this simulation method, theoretical backtracking and analysis can be performed on the defects of the scintillation structure after etching.

[0072] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for simulating the evolution of scintillation grating morphology, characterized in that, Includes the following steps: Step (1): Based on the pre-defined blazed structure of the blazed grating, an etching mask structure is pre-constructed; Step (2): Based on the morphological evolution of the mask structure during the etching process, determine the etching contour lines at different times and positions, and determine the motion properties of different contour lines. Step (3): Based on the motion attributes of different contour lines, determine the straight line equation of each contour line and the motion mode of each contour line; Step (4): Based on the motion mode of each contour line determined in step (3), and in combination with different etching processes, determine the motion direction of each contour line; Based on the direction and speed of motion of each contour line, the position and straight line equation of each contour line at different etching times are determined and updated; Step (5): Determine the simulated etching endpoint of the blazed grating etching morphology based on different etching processes; when the etching endpoint is reached, the simulation of the blazed grating etching morphology is completed.

2. The simulation method for the morphological evolution of blazed grating etching according to claim 1, characterized in that, In step (2), in detail, the contour lines of the etching shape at different positions of the mask structure during the etching process are determined based on the evolution of the etching morphology of the mask structure at different times and positions during the etching process.

3. The simulation method for the morphological evolution of blazed grating etching according to claim 2, characterized in that, During the etching process and before reaching the etching endpoint, the mask structure includes a first contour line, a second contour line, a third contour line, a fourth contour line, and a fifth contour line connected in sequence within one mask cycle. Based on the evolution of the etching morphology of the mask structure during the etching process, the properties of the two endpoints of each contour line are determined to determine the motion properties of each contour line.

4. The simulation method for the morphological evolution of blazed grating etching according to claim 3, characterized in that, The first contour line includes a fixed node and an active node arranged in sequence. The fixed nodes maintain different positions, and the active node drives the contour line to evolve with increasing etching depth. The second contour line includes two active nodes, which drive the contour line to evolve with increasing etching depth. The third contour line includes one active node and one passive node arranged in sequence. The active node drives the passive node to achieve contour line evolution with increasing etching depth. The fourth contour line includes two passive nodes... The contour line formed by the two passive nodes evolves as the etching depth increases; the fifth contour line includes passive nodes and fixed nodes arranged in sequence, and the contour line formed by the passive nodes and the fixed nodes evolves as the etching depth increases; each active node, passive node and fixed node is arranged in sequence along the direction of light propagation in the blazed grating or the opposite direction of propagation, and each active node, passive node and fixed node defines the motion properties of each contour line.

5. The simulation method for the morphological evolution of blazed grating etching according to claim 3, characterized in that, In step (3), based on the motion properties of the different contour lines, the equation of the straight line for each contour line is determined, specifically based on the formula: The equation of the line for each contour line is determined to determine the trajectory of each contour line. (x1, y1) and (x2, y2) represent the position coordinates of any two points on a certain contour line of the mask structure, and (x, y) represent the equation of the line for the contour line. Based on the different motion attributes of different contour lines and the motion rate of different contour lines, the motion mode of different contour lines is determined.

6. The simulation method for the morphological evolution of blazed grating etching according to claim 5, characterized in that, Determining the motion mode of different contour lines includes obtaining the motion mode along the ion beam etching direction based on the etching rate at different positions and the etching direction determined by the mask structure.

7. The simulation method for the morphological evolution of blazed grating etching according to claim 1, characterized in that, In step (4), the position and straight line equation of each contour line under different etching times are determined and updated. Specifically, under different etching times, the starting point and ending point of the new line segment of the contour line are reconstructed at the intersection point between different positions of each contour line. Based on the movement direction and movement speed of each contour line, the position and straight line equation of each contour line under different etching times are determined and updated, and the movement path of each contour line is replanned.

8. The simulation method for the morphological evolution of blazed grating etching according to claim 3, characterized in that, In step (5), the simulated etching endpoint of the blazed grating etching morphology is determined based on different etching processes, including determining that the etching endpoint has been reached when the line segment length of the fifth contour line is less than a certain threshold.

9. The simulation method for the morphological evolution of blazed grating etching according to claim 3, characterized in that, In step (5), the simulated etching endpoint of the blazed grating etching morphology is determined based on different etching processes, including stopping etching when the two endpoints of the fifth contour line coincide.

10. The simulation method for the morphological evolution of blazed grating etching according to claim 3, characterized in that, In step (5), the simulated etching endpoint of the blazed grating etching morphology is determined based on different etching processes. This includes determining that the etching endpoint is reached when the active node of the first contour line coincides with the fixed node of the fifth contour line in any two adjacent mask cycles of the mask structure.

Images