Superlens lithography mask generation

Abstract

In an example, a target design of a superlens is obtained. The target design includes target design superatoms. A mask design is generated, by one or more processors, based on an area deviation of a to-be-fabricated superatom of the superlens from the target design superatom. The mask design may be generated in some examples using rule-based corrections, such as using lookup tables (LUTs), and in some examples may be generated using model-based corrections.

Description

[0001] Related applications

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application Serial No. 63 / 487,360, filed on February 28, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to generating photolithographic masks for fabricating metalens. Background Art

[0004] A metalens is typically a flat lens that manipulates the phase, amplitude, and / or polarization of light to focus it. Instead of refraction, a metalens can manipulate the phase, amplitude, and / or polarization of light to focus it. A metalens uses sub-resolution features to manipulate the phase, amplitude, and / or polarization of light and the lens focus. Various structures within a metalens can be implemented to manipulate the phase, amplitude, and / or polarization as desired. Metalens may have applications in virtual reality, augmented reality, and other applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present disclosure will be more fully understood through the detailed description given below and the accompanying drawings of the embodiments of the present disclosure. The accompanying drawings are used to provide knowledge and understanding of the embodiments of the present disclosure and do not limit the scope of the present disclosure to these specific embodiments. In addition, these drawings are not necessarily drawn to scale.

[0006] Figure 1 Here are some examples of methods for making metalenses.

[0007] Figure 2 This is the environment in which the superlens is made.

[0008] Figure 3A and Figure 3B Perspective and layout diagrams of the designed meta-atom according to some example goals, respectively.

[0009] Figure 4A and Figure 4B Perspective and layout diagrams of fabricated meta-atoms according to some examples, respectively.

[0010] Figure 5 Based on some examples used to generate Figure 1 The first method in mask design.

[0011] Figure 6 Based on some examples used to generate Figure 1 The second method of mask design.

[0012] Figure 7 It's a picture Figure 6The following are some examples of operations of the second method.

[0013] Figure 8 A diagram depicting an example computer system in which the example methods of the present disclosure may operate DETAILED DESCRIPTION

[0014] Various aspects of the present disclosure relate to generating photolithographic masks for making metalenses. According to some examples, when generating photolithographic masks to make metalenses, the area of ​​the subwavelength nanostructures to be made within the metalenses is taken into account. The subwavelength nanostructures made are generally structures that manipulate the phase, amplitude and / or polarization of light passing through the corresponding subwavelength nanostructures of the metalenses. Hereinafter, the subwavelength nanostructures may also be referred to as meta-atoms. Metalenses can be made using photolithography and etching techniques that may be common in integrated circuit fabrication. Some examples described herein relate to the generation of photolithographic masks used in the photolithography process for making metalenses.

[0015] A target design for a metalens can be created with respect to the desired optical function of the metalens. However, variations in fabrication may result in the fabricated metalens being different from the target design. For example, the lithographic process used to fabricate the metalens may be band-limited by the projection optics of the lithographic process. Band-limited aspects of the lithographic process may result in higher frequency light being filtered out of the exposed pattern, for example, when patterning the photoresist. Without the higher frequency light, corner rounding may occur in the photoresist pattern that is transferred to the metalens by etching. The corner rounding transferred to the metalens may deviate from the target design.

[0016] Deviations from the target design in the fabricated metalens can result in a loss in optical efficiency. Different types of deviations from the target design can affect optical efficiency. One type of deviation from the target design that can affect optical deviation is the deviation in area of ​​the fabricated metaatoms within the metalens from the target design metaatoms. A high correlation between efficiency loss and area deviation has been observed.

[0017] Therefore, the technical advantages of the present disclosure include, but are not limited to, reducing the optical efficiency loss of a fabricated metalens relative to a target design by accounting for area deviations. To address the technical issue of optical efficiency loss of a fabricated metalens relative to a target design, some examples described herein account for area deviations of the meta-atoms to be fabricated in the metalens when generating a photolithography mask to be used to fabricate the meta-atoms. Various examples reduce the area deviations of the fabricated meta-atoms relative to the target design, thereby achieving technical solutions or advantages for reducing the optical efficiency loss of the fabricated metalens relative to the target design. Other advantages or benefits may be achieved in various examples.

[0018] According to some examples, a metalens can be or include a layer of transmissive material having fabricated meta-atoms thereon. For example, during fabrication, the transmissive material can be a layer of silicon dioxide on a handle or support wafer (e.g., a silicon wafer), or can be a glass wafer (e.g., quartz, silicon dioxide, or another type of glass). Example fabricated meta-atoms can include silicon nitride (e.g., Si3N4), which can have any shape or pattern. For simplicity, the various examples described below illustrate meta-atoms as having a generally rectangular area, and so as not to obscure various aspects of the examples. However, any shape can be implemented for meta-atoms, whether regular, irregular, polygonal, free-form, etc.

[0019] Figure 1 1 is a method 100 of making a metalens according to some examples. Figure 2 The general environment to describe Figure 1 Method 100.

[0020] In block 102, a target design 202 for a metalens (including a pattern of target design meta-atoms 204) is obtained. Target design 202 may be a design of a metalens that achieves a desired optical function regardless of fabrication variations. Target design 202 may include a desired shape and pattern of target design meta-atoms 204. Figure 2 Illustration 202a of target design 202 in FIG shows a portion of target design 202 that includes a pattern of target design meta-atoms 204. The area pattern of target design meta-atoms 204 may vary throughout the design layout. For example, Figure 2 The target design of the pattern of meta-atoms 204 can be used for an achromatic metalens (as illustrated) or another type of metalens.

[0021] Return Reference Figure 1 In block 104, a mask design for a photolithography process is generated based on the area deviation of the to-be-fabricated meta-atoms of the metalens from the target design of the metalens. Various examples compensate for fabrication or process variations when generating the mask design. For example, as described above, the photolithography process may cause corners of exposed photoresist to be rounded, thereby causing corners of the etched material (e.g., meta-atoms) to also be rounded to transfer the pattern of the photoresist to the material. Figure 3A 、 Figure 3B 、 Figure 4A and Figure 4B The diagram illustrates the corner rounding that can occur. Figure 3A and Figure 3B 3 and 4. They are a perspective view and a layout view, respectively, of the target design meta-atom 302. In the layout view (eg, XY plane), the target design meta-atom 302 has a rectangular area, with sharp 90-degree corners in this example. Figure 4A and Figure 4B4 and 5. FIGURE 402 are perspective views and layout views of a fabricated meta-atom 402, respectively. The fabricated meta-atom 402 is generally rectangular, but has rounded corners. This rounded corners may be due to a photolithography process implemented to etch and pattern the material that produces the fabricated meta-atom 402. As described in detail later, the generation of a mask design can reduce the area deviation between a target design meta-atom and a meta-atom to be fabricated that is to be fabricated (e.g., etched) using a photolithography process that implements a photolithography mask fabricated based on the mask design. In some examples, the generation of the mask design attempts to make the area deviation between the target design meta-atom and the meta-atom to be fabricated zero (e.g., the area of ​​the target design meta-atom is equal to the area of ​​the meta-atom to be fabricated).

[0022] Return Reference Figure 1 In block 106, a photolithographic mask 210 is fabricated based on the mask design. The photolithographic mask 210 can be fabricated using any acceptable process. In block 108, a metalens 232 is fabricated, and fabrication of the metalens 232 includes using the photolithographic mask 210 in a photolithographic process. For example, the photolithographic mask 210 can be used in a photolithographic process to pattern a photoresist 212, and the patterned photoresist 212 is used as a mask for etching the metaatom material 214 into the metaatoms 234 of the metalens 232.

[0023] More specifically, the photolithography process may include generating light 220 from a light source 218 and transmitting the light 220 through a photolithography mask 210 to generate a light pattern. The light pattern is incident on a photoresist 212 to pattern the photoresist 212. The pattern of the photoresist 212 is then transferred to the meta-atom material 214 using the photoresist 212 as a mask during an etching process, thereby forming fabricated meta-atoms 234. The metalens 232 may also include a substrate 216 on which the meta-atom material 214, and thus the fabricated meta-atoms 234, are disposed. Inset 232a of the metalens 232 shows a portion of the metalens 232 including a pattern of fabricated meta-atoms 234 corresponding to the target design meta-atoms 204 inset 202a of the target design 202.

[0024] Figure 5 Based on some examples used in Figure 1A first method 500 for generating a mask design in block 104 of FIG. 1 can be a rule-based correction for generating a mask design. In block 502, a lookup table (LUT) is created based at least in part on area considerations of target design meta-atoms. The LUT is populated with various patterns of target design meta-atoms that can be implemented in the target design of the metalens. The LUT is indexed by the area of ​​the target design meta-atom and can also be indexed by the X size, Y size, and shape of the target design meta-atom. In addition, the LUT can be indexed by the size of adjacent meta-atoms. The mask size is a function of the target size and can also be a function of adjacent patterns. For each indexed target design meta-atom in the LUT, the LUT contains a corresponding mask pattern for a lithographic mask that produces a given to-be-fabricated meta-atom. For the indexed target design meta-atom, the corresponding to-be-fabricated meta-atom has a reduced area deviation relative to the indexed target design meta-atom, which can be an area deviation of zero. The mask pattern for a given target design meta-atom can be determined through physical experiments and / or lithography simulations, and the mask pattern used to fill the LUT for the given target design meta-atom is a mask pattern determined to appropriately reduce the area deviation between the given target design meta-atom and the meta-atom to be fabricated.

[0025] In block 504, a mask pattern corresponding to a target design metaatom is obtained from the LUT. For example, for a given target design metaatom, the area and size (if applicable) of the target design metaatom and the size of neighboring metaatoms (if applicable) are used to find (e.g., by indexing) a corresponding mask pattern. In block 506, a mask design is generated that includes the obtained mask pattern. The mask pattern can be placed in the mask design at a location corresponding to the corresponding target design metaatom in the target design.

[0026] Using mask design, a photolithography mask can be made and implemented in a photolithography process to form a fabricated superatom, such as Figure 1 As described in blocks 106 and 108 of FIG. Since a mask design including a mask pattern selected from a LUT is generated, and the LUT is populated with mask patterns to reduce area deviation, the area deviation of meta-atoms fabricated in the fabricated metalens relative to the target design meta-atoms of the target design can be reduced. The reduced area deviation may result in a reduced optical efficiency loss in the fabricated metalens.

[0027] Figure 6 Based on some examples used in Figure 1 The second method 600 for generating a mask design in block 104 of FIG. The second method 600 may be a model-based optical proximity correction (OPC) with redirection to generate a mask design. In block 602, an initial target design having target design meta-atoms is obtained, such as in FIG. Figure 1In block 102 of . In block 604, OPC with edge position error (EPE) is performed to obtain a mask design with a first perturbed meta-atom. OPC with EPE may perturb (e.g., move) the edges of various target design meta-atoms in an initial iteration to obtain a mask design with the first perturbed meta-atom. In subsequent iterations, OPC with EPE may also perturb the edges of a second perturbed meta-atom (described later) to obtain a mask design with the first perturbed meta-atom. For convenience herein, the area of ​​the first perturbed meta-atom at iteration N is designated as A PERTURB，N (σB N-1 ), where B0 = 0 when N = 1. In addition, for convenience in this paper, the target bias determined at iteration N is designated as B N , and the damping factor is designated as σ. The target bias and damping factor are described below. For clarity, the target bias entering the initial iteration N=1 is initialized to zero (eg, B0=0). Block 604 can implement any OPC using EPE techniques.

[0028] In block 606, the fabrication of the meta-atom to be fabricated is simulated based on the mask design having the first perturbed meta-atom to determine a simulated area of ​​the meta-atom to be fabricated. For example, the simulation may be implemented using any lithography process simulation software. The simulation may use a simulated lithography mask fabricated according to the mask design having the first perturbed meta-atom to simulate a lithography process, wherein the lithography process is used to form (e.g., pattern a photoresist for mask etching) the simulated meta-atom to be fabricated. Using the simulation results, the simulated area of ​​the meta-atom to be fabricated may be determined. For convenience herein, the simulated area of ​​the meta-atom to be fabricated at iteration N is designated as A 2BFAB，N (A PERTURB，N (σB N-1 )) or simply referred to as A 2BFAB，N .

[0029] In block 608, the area deviation of the simulated area of ​​the to-be-fabricated metaatom from the target area of ​​the target design metaatom is determined. The area deviation is the difference between the target area of ​​the simulated to-be-fabricated metaatom and the corresponding target design metaatom. As previously indicated, the simulated area is generated by simulating the fabrication of the to-be-fabricated metaatom based on the corresponding first perturbed metaatom in the mask design. The area of ​​the first perturbed metaatom is a function of any perturbations to the edges in block 604 and any application of target biases (described subsequently) in previous iterations, if any. For convenience herein, the target area of ​​the target design metaatom is designated as A TARGET Therefore, in N iterations, the area deviation ΔA between a given to-be-made superatom and the corresponding target design superatom is N It can be summarized as follows in equation (1).

[0030] ΔAN =A TARGET –A 2BFAB,N ((A PERTURB,N (σB N-1 )) Equation (1)

[0031] In block 608 , the area deviation of each to-be-fabricated metaatom of the mask design and the corresponding target design metaatom may be determined.

[0032] In block 610, it is determined whether the area deviation is within the design specification. For example, the design specification may be that no area deviation is greater than 10% of the area of ​​the corresponding target design meta-atom. The design specification may be further tightened to, for example, 2%, which may be a cause of process drift during fabrication. If it is determined in block 610 that the area deviation is within the design specification, then in block 612 the mask design is returned as the mask design to be fabricated (e.g., in Figure 1 106).

[0033] If the determination in block 610 is that the area deviation (e.g., any one or more area deviations) is not within the design specification, then in block 612, target bias(es) are determined based on the area(s) of the simulated to-be-fabricated meta-atom(s) and the area(s) of the target design meta-atom(s). The target bias is the amount by which the size of the first perturbed meta-atom will be further perturbed, which results in modifying the area of ​​the first perturbed meta-atom. Typically, a target bias is determined that can reduce the area deviation in subsequent iterations. In the current iteration N, the area deviation in the subsequent iteration (N+1) may be an approximation, which for convenience is designated as For example, the difference between the target area of ​​the target design meta-atom and the simulated area approximation of the to-be-made meta-atom in the next iteration can be reduced, such as reduced to approximately zero. In the next iteration, the simulated area approximation of the to-be-made meta-atom can be based on an incremental target bias, which for convenience herein is designated as δB at iteration N. N For the sake of convenience, in the next iteration (N+1), the simulation area of ​​the superatom to be made is approximately designated as Therefore, the incremental target bias can be determined by generally solving equation (2).

[0034]

[0035] Target bias B at iteration N N The target bias B from the previous iteration N-1 can be accumulated or otherwise accounted for N-1 and the incremental target bias δB at iteration N N (For example, B N =B N-1 +δB N). Determining the target bias (and subsequently applying the target bias) can generally maintain the overall shape of the area of ​​the target design meta-atom to the area of ​​the second perturbed meta-atom (e.g., maintain shape fidelity).

[0036] Target bias B N can be or include any number of target offsets along the corresponding axis. For example, for a square target design area, the target offset B N The x and y directions can be equal, so that B N =B x，N =B y，N In other examples, for non-square rectangular areas, the target offset B N can be a set including a target offset in the x direction and another target offset in the y direction, such that B N ={B x，N , B y，N}, where B x，N ≠B y，N Other shapes of target design area may have different sets of target offsets. For example, a free-form shape may have a large number of target offsets along any given axis. In some examples, equation (2) above may be solved analytically, and in other examples (such as for free-form shapes) may be solved numerically.

[0037] In block 616, target bias(es) are applied to the first perturbed metaatom(s) to obtain a second perturbed metaatom. For example, one or more dimensions of the perturbed metaatom may be modified based on the corresponding target bias, such as by adding or subtracting the target bias from the dimension(s). The target bias may be applied (e.g., added or subtracted) symmetrically around the center of the corresponding perturbed metaatom. A damping factor σ may be applied to the target bias to improve convergence of the correction iterations by reducing oscillatory overcorrections. For example, in the initial iteration(s), the damping factor may be between 0.7 and 0.9, and may be reduced to, for example, about 0.5 in subsequent iterations. For convenience herein, the area of ​​the second perturbed metaatom to which the target bias is applied at iteration N is designated as A PERTURB，N (σB N ).

[0038] Then, in a subsequent iteration, OPC with EPE is performed on the second perturbed meta-atom with the target bias(es) to obtain a mask design with the first perturbed meta-atom in block 604. The loop of blocks 604, 606, 608, 610, 614, 616 may be performed for any number of iterations, such as until the area deviation is within the design specification determined in block 610. A loop counter and a condition to exit the loop based on the loop counter or another condition may be implemented, for example, to avoid infinite loops.

[0039] Using mask design, a photolithography mask can be made and implemented in a photolithography process to form a fabricated superatom, such as Figure 1 As described in blocks 106 and 108 of FIG. , because the mask design is generated based on the biased target design meta-atoms, the area deviation of the meta-atoms fabricated in the fabricated metalens relative to the target design meta-atoms can be reduced. The reduced area deviation may result in a reduced optical efficiency loss in the fabricated metalens.

[0040] exist Figure 7 Described in the context of Figure 6 A simple example of some operations of the second method 600 is shown. In this example, the area shape of the target design meta-atom is a square. For simplicity, it is assumed that no perturbation occurs in block 604. That is, in an initial iteration N=1, for a given target design meta-atom, the area of ​​the first perturbed meta-atom is equal to the area of ​​the target design meta-atom (as shown in equation (3)), and for subsequent iterations N>1, the area of ​​the first perturbed meta-atom is equal to the area of ​​the second perturbed meta-atom to which the target bias was applied in the previous iteration (N-1) (as shown in equation (4)). In general, these assumptions lead to the following results:

[0041] For N=1, A PERTURB,1 (σB0=0)=A TARGET Equation (3)

[0042] For N>1,

[0043] In addition, since the area shape of the target design meta-atom is square, the incremental area change of the first perturbed meta-atom due to the incremental target bias at iteration N can be summarized as shown in Equation (5).

[0044]

[0045] Figure 7 A target design superatom (e.g., A) having a center 704 is shown. TARGET ) area 702. In this example, the shape of area 702 is a square. In the first iteration N=1, based on the assumption of equation (3) above, the area 706 of the first perturbed metaatom (after block 606) is equal to the area 702 of the target design metaatom. The simulation based on the area 706 of the first perturbed metaatom generates a simulated area 708 (e.g., A) of the metaatom to be fabricated. 2BFAB，1 (A PERTURB，1 (σB0=0))). Assume that the area deviation ΔA1 exceeds the design specification.

[0046] To solve for the target bias, we assume that the area of ​​the meta-atom to be produced is approximately the area of ​​the first perturbed meta-atom in the next iteration. Therefore, for iteration N=1, the area of ​​the meta-atom to be produced in the next iteration N=2 is approximately equal to the area of ​​the first perturbed meta-atom in the next iteration N=2 perturbed by the incremental target bias (e.g. By applying the incremental target bias, the area of ​​the first perturbed meta-atom at the next iteration N=2 is approximately the simulated area of ​​the to-be-made meta-atom at the current iteration N=1 plus the incremental area change of the first perturbed meta-atom (e.g., A PERTURB,2 (δB1)=A 2BFAB,1 +δA PERTURB,1 (δB1)). Substituting these approximations into the above equation (2), we obtain the following equation (6).

[0047] 0=A TARGET -(A 2BFAB，1 +δA PERTURB，1 (δB1)) Equation (6)

[0048] Substituting equation (5) into equation (6), where B0 = 0, yields equation (7).

[0049]

[0050] Rearranging the terms of equation (7) yields equations (8) and (9) below.

[0051]

[0052] Solving equation (9) for the incremental target bias yields equation (10) below.

[0053]

[0054] Since there is no previous iteration of the target bias, the target bias for iteration N=1 is equal to the incremental target bias (eg, B1=δB1).

[0055] Apply the target bias together with the damping factor to the first perturbed metaatom to obtain the second perturbed metaatom (e.g. A PERTURB，1 (σB1)). Application of the target bias and damping factor results in an area 710 of the second perturbed meta-atom. The damping target bias is applied symmetrically about the center 704 along a given axis. Thus, half 712a of the damping target bias (e.g. ) is added to the length in the +x direction, and the other half 712b is added to the length in the -x direction. Similarly, half 712c of the damping target offset is added to the length in the +y direction, and the other half 712d is added to the length in the -y direction.

[0056] In the second iteration N=2, based on the assumption of equation (4) above, the area 710 of the first perturbed meta-atom (after block 606) is equal to the area 710 of the second perturbed meta-atom (e.g., A) applied to the target bias in the previous iteration N=1. PERTURB，2 (σB1)=A PERTURB，1 (σB1)). Based on the simulation of the area 710 of the first perturbed meta-atom, a simulated area 714 of the meta-atom to be fabricated (e.g., A 2BFAB，2 (A PERTURB，2 (σB1))). Assume that the area deviation ΔA2 exceeds the design specification.

[0057] To solve for the target bias, we assume that the area of ​​the meta-atom to be produced is approximately the area of ​​the first perturbed meta-atom in the next iteration. Therefore, for iteration N=2, the area of ​​the meta-atom to be produced in the next iteration N=3 is approximately equal to the area of ​​the first perturbed meta-atom in the next iteration N=3 perturbed by the incremental target bias (e.g. By applying the incremental target bias, the area of ​​the first perturbed meta-atom at the next iteration N=3 is approximately the simulated area of ​​the to-be-made meta-atom at the current iteration N=2 plus the incremental area change of the first perturbed meta-atom (e.g., A PERTURB，3 (σB1+δB2)=A 2BFAB，2 +δA PERTURB，2 Substituting these approximations into equation (2) above yields equation (11) below.

[0058] 0=A TARGET -(A 2BFAB，2 +δA PERTURB,2 (δB2)) Equation (11)

[0059] Substituting equation (5) into equation (11), we obtain equation (12).

[0060]

[0061] Rearranging the terms from equation (12) yields equation (13), from which the quadratic formula is used to solve for the incremental target bias in equation (14) below.

[0062]

[0063] The iterative target bias from the previous iteration N=1 is added to the incremental target bias to obtain the target bias for iteration N=2 (eg, B2=B1+δB2).

[0064] Apply the target bias together with the damping factor to the first perturbed metaatom to obtain the second perturbed metaatom (e.g. A PERTURB，2(σB2)). Application of the target bias and damping factor results in the area of ​​the second perturbed meta-atom 716. As previously described, the damped target bias is applied symmetrically about the center 704 along a given axis.

[0065] In the third iteration N=3, based on the assumptions of equation (4) above, the area 716 of the first perturbed meta-atom (after block 606) is equal to the area 716 of the second perturbed meta-atom with the target bias applied in the previous iteration N=2 (e.g., A PERTURB，3 (σB2)=A PERTURB，2 (σB2)). Based on the simulation of the area 716 of the first perturbed meta-atom, a simulated area 718 of the meta-atom to be fabricated (e.g., A 2BFAB，3 (A PERTURB，3 (σB2))). Assume that the area deviation ΔA3 is within the design specification. Therefore, the area 716 of the first perturbed meta-atom is returned to generate the design mask.

[0066] Figure 8 An example machine of a computer system 800 is illustrated within which a set of instructions for causing the machine to perform any one or more of the methodologies discussed herein may be executed. More particularly, the computer system 800 may include stored instructions (e.g., stored on a non-transitory computer-readable medium) that, when executed by one or more processors of the computer system 800, implement in whole or in part the methods described herein. Figure 1 、 Figure 5 and Figure 6 In various examples, the machine may be connected (e.g., using a network) to other machines in a LAN, an intranet, an extranet, and / or the Internet. The machine may operate in the capacity of a server or a client user machine in a client-server network environment, as a peer machine in a peer-to-peer (or distributed) network environment, or as a server or a client user machine in a cloud computing infrastructure or environment.

[0067] The machine may be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), cellular phone, web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (serial or otherwise) that specify actions to be taken by the machine. Further, while a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions for performing any one or more of the methodologies discussed herein.

[0068] The example computer system 800 includes a processing device 802, a main memory 804 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM)), a static memory 806 (e.g., flash memory, static random access memory (SRAM), etc.)), and a data storage device 818, which communicate with each other via a bus 830.

[0069] The processing device 802 represents one or more processors such as a microprocessor, a central processing unit, or the like. More particularly, the processing device may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or a processor that implements other instruction sets or a processor that implements a combination of instruction sets. The processing device 802 may also be one or more special-purpose processing devices such as an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), a network processor, or the like. The processing device 802 may be configured to execute instructions 826 for performing the operations and steps described herein.

[0070] The computer system 800 may also include a network interface device 808 that communicates over a network 820. The computer system 800 may also include a video display unit 810 (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device 812 (e.g., a keyboard), a cursor control device 814 (e.g., a mouse), a graphics processing unit 822, a signal generating device 816 (e.g., a speaker), the graphics processing unit 822, a video processing unit 828, and an audio processing unit 832.

[0071] The data storage device 818 may include a machine-readable storage medium 824 (also referred to as a non-transitory computer-readable storage medium) having stored thereon one or more sets of instructions 826 or software that implement any one or more of the methods or functions described herein. The instructions 826 may also reside, completely or at least partially, within the main memory 804 and / or within the processing device 802 during execution thereof by the computer system 800, the main memory 804 and the processing device 802 also constituting machine-readable storage media.

[0072] In some implementations, the instructions 826 include instructions that implement functionality corresponding to the present disclosure. Although the machine-readable storage medium 824 is shown as a single medium in the example implementation, the term "machine-readable storage medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database and / or associated caches and servers) that store one or more instruction sets. The term "machine-readable storage medium" should also be taken to include any medium that can store or encode an instruction set for execution by a machine and cause the machine and processing device 802 to perform any one or more methods of the present disclosure. Therefore, the term "machine-readable storage medium" should be taken to include, but is not limited to, solid-state memory, optical media, and magnetic media.

[0073] Some portions of the previous detailed description have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are provided as a means for those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm may be a sequence of operations that produces a desired result. Operations are those requiring physical manipulation of physical quantities. Such quantities may take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated. Such signals may be referred to as bits, values, elements, symbols, characters, terms, numbers, and the like.

[0074] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as will be apparent from this disclosure, it will be understood that throughout this specification certain terms refer to the actions and processes of computer systems or similar electronic computing devices that manipulate data represented as physical (electronic) quantities within the computer system's registers and memories and transform it into other data similarly represented as physical quantities within the computer system's memories or registers or other such information storage devices.

[0075] The present disclosure also relates to an apparatus for performing the operations herein. The apparatus may be specially constructed for the intended purpose, or it may include a computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a non-transitory computer-readable storage medium, such as, but not limited to, any type of disk including a floppy disk, an optical disk, a CD-ROM, and a magneto-optical disk, a read-only memory (ROM), a random access memory (RAM), an EPROM, an EEPROM, a magnetic card or an optical card, or any type of medium suitable for storing electronic instructions (each coupled to a computer system bus).

[0076] The algorithms and displays proposed herein are not inherently related to any particular computer or other device. Various other systems may be used in conjunction with the program according to the teachings herein, or it may prove convenient to construct a more specialized device to perform the method. Additionally, the present disclosure is not described with reference to any particular programming language. It will be appreciated that various programming languages ​​may be used to implement the teachings of the present disclosure described herein.

[0077] The present disclosure can be provided as a computer program product or software that can include a machine-readable storage medium having instructions stored thereon, and the instructions can be used to program a computer system (or other electronic device) to perform a process according to the present disclosure. A machine-readable storage medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a machine-readable (e.g., computer-readable) storage medium includes a machine-readable (e.g., computer-readable) storage medium, such as a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium, an optical storage medium, a flash memory device, etc.

[0078] An example method includes obtaining a target design for a metalens. The target design includes target design meta-atoms. One or more processors generate a mask design based on an area deviation of a to-be-fabricated meta-atom of the metalens relative to the target design meta-atoms.

[0079] Another example is a non-transitory computer-readable storage medium comprising stored instructions. When executed by one or more processors, the instructions cause the one or more processors to obtain a target design for a metalens and generate a mask design based on an area deviation. The target design includes target design meta-atoms. The area deviation of a to-be-fabricated meta-atom of the metalens relative to the target design meta-atoms is determined.

[0080] Yet another example is a method. A target design for a metalens is obtained. The target design includes a target design metaatom. The target design metaatom has a corresponding first metaatom to be fabricated. A mask design is generated by one or more processors. The mask design includes a modified metaatom corresponding to the target design metaatom. The modified metaatom has a corresponding second metaatom to be fabricated. For each modified metaatom in the modified metaatoms, an area deviation between an area of ​​the corresponding target design metaatom and an area of ​​the corresponding second metaatom to be fabricated is less than an area deviation between an area of ​​the corresponding target design metaatom and an area of ​​the corresponding first metaatom to be fabricated.

[0081] In the foregoing disclosure, the implementation of the present disclosure has been described with reference to its specific example implementation. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the implementation of the present disclosure as set forth in the following claims. Where the present disclosure relates to some elements in the singular tense, more than one element may be depicted in the accompanying drawings, and similar elements are marked with similar numerals. Therefore, the present disclosure and the accompanying drawings are to be considered illustrative rather than restrictive.

Claims

1. A method comprising: obtaining a target design of a metalens, the target design comprising a target design metaatom; as well as A mask design is generated by one or more processors based on an area deviation of the to-be-fabricated meta-atom of the metalens relative to the target design meta-atom.

2. The method according to claim 1, further comprising: fabricating a photolithography mask based on the mask design; as well as Fabricating the metalens includes using the photolithography mask in a photolithography process.

3. The method of claim 1 , wherein generating the mask design comprises: obtaining a lookup table comprising mask patterns, each of the mask patterns being indexed in the lookup table at least in part by an area of ​​a corresponding target design metaatom; For each target design superatom in the target design superatoms, obtaining a mask pattern corresponding to the area of ​​the corresponding target design superatom from the lookup table; as well as The mask design including the obtained mask pattern is generated.

4. The method of claim 1 , wherein generating the mask design comprises: performing optical proximity correction based on the target design using an edge position error technique to obtain a temporary mask design including a first perturbed meta-atom; simulating a superatom to be fabricated based on the temporary mask design; Determining an area deviation between the simulated meta-atom to be fabricated and the target designed meta-atom; When the area deviation is within a design specification, assigning the temporary mask design as the mask design; as well as When the area deviation is not within the design specification: For each of the area deviations that is not within the design specification, determining a target bias based on an area of ​​a corresponding simulated meta-atom to be fabricated and an area of ​​a corresponding target design meta-atom; as well as For each determined target bias, the corresponding target bias is applied to the corresponding first perturbation meta-atom in the temporary mask design to obtain the corresponding second perturbation meta-atom in the temporary mask design.

5. The method of claim 4 , wherein the target bias is determined based on a difference between the area of ​​the corresponding target design metaatom and an approximation of the area of ​​a to-be-simulated metaatom to be fabricated, the area of ​​the to-be-simulated metaatom to be fabricated being based on an incremental area change of the corresponding simulated metaatom to be fabricated and the corresponding first perturbed metaatom based on an incremental target bias.

6. The method of claim 4, wherein applying the corresponding target bias further comprises applying a damping factor having the corresponding target bias to the corresponding first perturbation meta-atom in the temporary mask design to obtain the corresponding second perturbation meta-atom in the temporary mask design.

7. The method of claim 1 , wherein generating the mask design comprises: Iteratively perform the following until the area deviation is within the design specifications: performing optical proximity correction using an edge position error technique based on a design to obtain a temporary mask design including a first perturbed meta-atom, the design being the target design in an initial iteration and the temporary mask design from a previous iteration in a subsequent iteration; simulating a superatom to be fabricated based on the temporary mask design; Determining the area deviation between the simulated meta-atom to be fabricated and the target designed meta-atom; For each of the area deviations that is not within the design specification, determining a target bias based on an area of ​​a corresponding simulated meta-atom to be fabricated and an area of ​​a corresponding target design meta-atom; as well as For each determined target bias, applying the corresponding target bias to the corresponding first perturbation superatom in the temporary mask design to obtain the corresponding second perturbation superatom in the temporary mask design; as well as The temporary mask design is assigned as the mask design.

8. The method of claim 7 , wherein the target bias is determined based on a difference between the area of ​​the corresponding target design metaatom and an approximation of the area of ​​a to-be-simulated to-be-fabricated metaatom, the area of ​​the to-be-simulated to-be-fabricated metaatom being based on an incremental area change of the corresponding simulated to-be-fabricated metaatom and a corresponding first perturbation metaatom based on an incremental target bias.

9. The method of claim 7, wherein applying the corresponding target bias further comprises applying a damping factor having the corresponding target bias to the corresponding first perturbation meta-atom in the temporary mask design to obtain the corresponding second perturbation meta-atom in the temporary mask design.

10. A non-transitory computer-readable storage medium comprising stored instructions that, when executed by one or more processors, cause the one or more processors to: obtaining a target design of a metalens, the target design comprising a target design metaatom; and A mask design is generated based on an area deviation of the to-be-fabricated meta-atom of the metalens relative to the target design meta-atom.

11. The non-transitory computer-readable storage medium of claim 10, wherein the instructions, when executed by the one or more processors, cause the one or more processors to generate the mask design further comprise instructions, when executed by the one or more processors, cause the one or more processors to: obtaining a lookup table comprising mask patterns, each of the mask patterns being indexed in the lookup table at least in part by an area of ​​a corresponding target design metaatom; For each target design superatom in the target design superatoms, obtaining a mask pattern corresponding to the area of ​​the corresponding target design superatom from the lookup table; as well as The mask design including the obtained mask pattern is generated.

12. The non-transitory computer-readable storage medium of claim 10 , wherein the instructions, when executed by the one or more processors, cause the one or more processors to generate the mask design further comprise instructions, when executed by the one or more processors, cause the one or more processors to: performing optical proximity correction based on the target design using an edge position error technique to obtain a temporary mask design including a first perturbed meta-atom; simulating a superatom to be fabricated based on the temporary mask design; Determining an area deviation between the simulated meta-atom to be fabricated and the target designed meta-atom; When the area deviation is within a design specification, assigning the temporary mask design as the mask design; as well as When the area deviation is not within the design specification: For each of the area deviations that is not within the design specification, determining a target bias based on an area of ​​a corresponding simulated meta-atom to be fabricated and an area of ​​a corresponding target design meta-atom; as well as For each determined target bias, the corresponding target bias is applied to the corresponding first perturbation meta-atom in the temporary mask design to obtain the corresponding second perturbation meta-atom in the temporary mask design.

13. The non-transitory computer-readable storage medium of claim 12 , wherein the target bias is determined based on a difference between the area of ​​the corresponding target design metaatom and an approximation of the area of ​​a to-be-simulated to-be-fabricated metaatom, the area of ​​the to-be-simulated to-be-fabricated metaatom being based on an incremental area change of the corresponding simulated to-be-fabricated metaatom and the corresponding first perturbed metaatom based on an incremental target bias.

14. The non-transitory computer-readable storage medium of claim 10 , wherein the instructions, when executed by the one or more processors, cause the one or more processors to generate the mask design further comprise instructions, when executed by the one or more processors, cause the one or more processors to: Iteratively perform the following until the area deviation is within the design specifications: performing optical proximity correction using an edge position error technique based on a design to obtain a temporary mask design including a first perturbed meta-atom, the design being the target design in an initial iteration and the temporary mask design from a previous iteration in a subsequent iteration; simulating a superatom to be fabricated based on the temporary mask design; Determining the area deviation between the simulated meta-atom to be fabricated and the target designed meta-atom; For each of the area deviations that is not within the design specification, determining a target bias based on an area of ​​a corresponding simulated meta-atom to be fabricated and an area of ​​a corresponding target design meta-atom; as well as For each determined target bias, applying the corresponding target bias to the corresponding first perturbation superatom in the temporary mask design to obtain the corresponding second perturbation superatom in the temporary mask design; as well as The temporary mask design is assigned as the mask design.

15. The non-transitory computer-readable storage medium of claim 14, wherein the target bias is determined based on a difference between the area of ​​the corresponding target design metaatom and an approximation of the area of ​​a to-be-simulated to-be-fabricated metaatom, the area of ​​the to-be-simulated to-be-fabricated metaatom being based on an incremental area change of the corresponding simulated to-be-fabricated metaatom and a corresponding first perturbation metaatom based on an incremental target bias.

16. A method comprising: Obtaining a target design of a metalens, the target design including a target design metaatom, the target design metaatom having a corresponding first metaatom to be fabricated; as well as A mask design is generated, by one or more processors, including modified meta-atoms corresponding to the target design meta-atom, the modified meta-atom having a corresponding second meta-atom to be fabricated, wherein for each modified meta-atom in the modified meta-atoms, an area deviation between an area of ​​the corresponding target design meta-atom and an area of ​​the corresponding second meta-atom to be fabricated is less than an area deviation between the area of ​​the corresponding target design meta-atom and an area of ​​the corresponding first meta-atom to be fabricated.

17. The method of claim 16, wherein generating the mask design based on the area of ​​the target design meta-atom is rule-based.

18. The method of claim 16, wherein generating the mask design uses a lookup table (LUT) that includes available modified meta-atoms based on corresponding areas of target design meta-atoms.

19. The method of claim 16, wherein generating the mask is model-based based on an approximate area deviation of a corresponding area of ​​a target design meta-atom and a corresponding area of ​​a simulated to-be-fabricated meta-atom.

20. The method of claim 16, wherein generating the mask design comprises, for each of the modified superatoms: determining a target bias based on an area of ​​the corresponding target design meta-atom and an approximation of the area of ​​the to-be-fabricated meta-atom resulting from the corresponding modified meta-atom; and The target bias is applied to the area of ​​the corresponding target design meta-atom, wherein the target bias applied to the area of ​​the corresponding target design meta-atom at least partially obtains the corresponding modified meta-atom.

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