Micromirror assembly and direct writing photoetching system
By employing hexagonal arrays of micromirrors and microconvex mirrors in the direct-write lithography system, the problem of low light source utilization has been solved, improving the efficiency of the lithography system and reducing the cost of light source acquisition.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 张江国家实验室
- Filing Date
- 2024-10-21
- Publication Date
- 2026-04-21
AI Technical Summary
In existing direct-write lithography systems, the arrangement of micromirror arrays and micro-convex mirror arrays results in low light source utilization, making it difficult to meet the requirements of high-resolution lithography, and the cost of obtaining the wavelength of high-cost light sources is also high.
By employing a compact hexagonal arrangement of micromirror arrays and microconvex mirror arrays, a hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror, thereby improving the effective utilization rate of the light source.
By improving the effective utilization rate of the light source, the throughput and production efficiency of the lithography system are enhanced, while the cost of acquiring the light source is reduced.
Smart Images
Figure CN121900104A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of maskless lithography exposure system technology, and more particularly to a micromirror assembly and a direct-write lithography system. Background Technology
[0002] Laser-direct writing lithography eliminates the need for photomasks, allowing for the flexible writing of various micro and nano patterns and holding immense application potential. In current direct-writing lithography systems, the most typical arrangement of digital micromirror devices (DMDs) and micromirror arrays is such that the lines connecting the center points of adjacent units form a square (e.g., ...). Figure 1 and Figure 2 (As shown). The micromirror array units in DMD are square, and the microconvex mirror array units are circular, with a one-to-one correspondence between the center positions of the lenses in the micromirror array and the microconvex mirror array. This arrangement has a maximum duty cycle of π / 4 ≈ 0.785, and the maximum utilization rate of light reflected from the micromirror array to the microconvex mirror array is 0.785. High-resolution photolithography requires shorter wavelength light sources, which are very expensive to obtain; therefore, improving the utilization rate of light sources is extremely urgent. Summary of the Invention
[0003] This application discloses a micromirror assembly and a direct-write lithography system. In this system, the center points of the six micromirrors adjacent to any one of the micromirrors in the micromirror array and microconvex mirror array form a hexagon, which is compact, improves the duty cycle, and thus improves the effective utilization rate of the light source.
[0004] To achieve the above objectives, this application provides the following technical solution:
[0005] In a first aspect, this application provides a direct-write lithography system, comprising a light source, a micromirror array, a microconvex mirror array, and a stage arranged sequentially.
[0006] The light source is used to generate illumination light toward the micro-mirror array;
[0007] The micro-mirror array is used to modulate the illumination light into a target pattern beam and direct it toward the micro-convex mirror array;
[0008] The micro-convex mirror array is used to receive the target pattern beam, process it into a focused array, and project it onto the worktable;
[0009] The worktable is used to hold the wafer;
[0010] The number of micromirrors in the micromirror array is the same as the number of microconvex mirrors in the microconvex mirror array, and their center positions correspond one-to-one.
[0011] A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either six micromirrors adjacent to any one microreflector or six microconvex mirrors adjacent to any one microconvex mirror.
[0012] The aforementioned direct-write lithography system uses a combination of micromirror arrays and micro-convex mirror arrays to form a dynamic mask for dynamic exposure. In both the micromirror and micro-convex mirror arrays, the number of micromirrors and micro-convex mirrors is the same, and their centers correspond one-to-one. The arrangement of these arrays is such that the center points of any six adjacent micromirrors form a hexagon, creating a hexagonal close-packed structure with a compact design. Compared to a square arrangement where the center points of adjacent micromirrors are connected, the arrangement of the micromirror and micro-convex mirror arrays in this application increases the duty cycle (the ratio of the effective area for light transmission to the total area) by 15%. In other words, during the lithography process, the effective area for light transmission in the micromirror and micro-convex mirror arrays increases, significantly improving the utilization rate of the light source, which is beneficial for increasing throughput and improving the production efficiency of lithographic wafers.
[0013] In some embodiments, the hexagon formed by connecting the center points of the six micromirrors adjacent to any one of the micromirrors includes a first micromirror, a second micromirror, a third micromirror, a fourth micromirror, a fifth micromirror, and a sixth micromirror; the first micromirror is aligned with the second micromirror; the third micromirror is aligned with the fourth micromirror; and the fifth micromirror is aligned with the sixth micromirror.
[0014] The distance between the center point of the first micromirror and the center point of the second micromirror is a0; the distance between the center point of the first micromirror and the center point of the third micromirror is a0; the distance between the center point of the second micromirror and the center point of the fourth micromirror is b; where b ≥ a0;
[0015] The angle between the line connecting the center point of the first micromirror and the center point of the second micromirror and the scanning direction of the direct-write lithography system is θ, where 0 rad < θ ≤ 0.15 rad;
[0016] The angle between the line connecting the center point of the first micromirror and the center point of the second micromirror and the line connecting the center point of the first micromirror and the center point of the third micromirror is α, where 1.04 rad ≤ α ≤ 1.57 rad.
[0017] The distance between the exposure center points formed by the first micromirror and the second micromirror in the scanning direction is pd, and the distance perpendicular to the scanning direction is qd; the distance between the exposure center points formed by the first micromirror and the third micromirror in the scanning direction is md, and the distance perpendicular to the scanning direction is nd, where p, q, m, and n are all positive integers, and n < p-1. d represents the grid period of the pixelated target pattern.
[0018] In some embodiments, the shape of each micromirror in the micromirror array includes either a circle or a hexagon.
[0019] In some embodiments, each micro-convex mirror in the micro-convex mirror array is circular in shape.
[0020] In some embodiments, the direct-write lithography system further includes an absorption device disposed between the micromirror array and the microconvex mirror array;
[0021] The micromirror array includes a first working state and a second working state; when in the first working state, the reflected light from the micromirror array is directed toward the microconvex mirror array; when in the second working state, the reflected light from the micromirror array is absorbed by the absorption device.
[0022] In some embodiments, when the micromirror array is in a first working state, the reflected light from any one of the micromirrors in the micromirror array covers the corresponding microconvex mirror in the microconvex mirror array.
[0023] In some embodiments, the direct-write lithography system further includes a light shaping device disposed between the light source and the micromirror array, for processing the illumination light generated by the light source into parallel light.
[0024] In some embodiments, the direct-write lithography system further includes an imaging system disposed between the micro-mirror array and the stage, for processing the focused dot array formed by the micro-mirror array into an exposure dot array and imaging it onto the wafer of the stage.
[0025] In some embodiments, the wavelength of the light source is less than or equal to 100 nm.
[0026] In some embodiments, the total duty cycle of the micromirror array and the microconvex mirror array is 0.8-0.906.
[0027] Secondly, this application provides a micromirror assembly for direct-write lithography, including a micromirror array and a micro-convex mirror array, wherein the micromirror array and the micro-convex mirror array are arranged along an optical path;
[0028] The micro-mirror array is used to generate a target pattern beam based on the illumination light and direct it toward the micro-convex mirror array;
[0029] The micro-convex mirror array is used to generate a focal point array based on the target pattern beam;
[0030] The number of micromirrors in the micromirror array is the same as the number of microconvex mirrors in the microconvex mirror array, and their center positions correspond one-to-one.
[0031] A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either six micromirrors adjacent to any one microreflector or six microconvex mirrors adjacent to any one microconvex mirror.
[0032] Thirdly, this application provides a parameter design method for a micromirror assembly for direct-write lithography. The micromirror assembly includes a micromirror array and a micro-convex mirror array. A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either the six micromirrors adjacent to any one micromirror in the micromirror array or the six micro-convex mirrors adjacent to any one micro-convex mirror in the micro-convex mirror array.
[0033] The hexagon formed by connecting the center points of the six micromirrors adjacent to any one of the micromirrors includes a first micromirror, a second micromirror, a third micromirror, a fourth micromirror, a fifth micromirror, and a sixth micromirror; the first micromirror is in the same row as the second micromirror; the third micromirror is in the same row as the fourth micromirror; and the fifth micromirror is in the same row as the sixth micromirror.
[0034] The distance between the center point of the first micromirror and the center point of the second micromirror is a0; the distance between the center point of the first micromirror and the center point of the third micromirror is a0; the distance between the center point of the second micromirror and the center point of the fourth micromirror is b;
[0035] The angle between the line connecting the center point of the first micromirror and the center point of the second micromirror and the scanning direction is θ;
[0036] The angle between the line connecting the center point of the first micromirror and the center point of the second micromirror and the line connecting the center point of the first micromirror and the center point of the third micromirror is α;
[0037] The distance between the exposure center point formed by the first micromirror and the exposure center point formed by the second micromirror in the scanning direction is pd, and the distance perpendicular to the scanning direction is qd; the distance between the exposure center point formed by the first micromirror and the exposure center point formed by the third micromirror in the scanning direction is md, and the distance perpendicular to the scanning direction is nd.
[0038] The parameter design method includes:
[0039] Given positive integers p and q, calculate θ.
[0040] Let the positive integer n be p-1, and let the positive integer m be less than p-1. Given the largest integer, calculate α and n'; where n' is calculated from q, α, and θ.
[0041] When n = n', output n, m, p, q, α, θ.
[0042] In some embodiments, the parameter design method further includes: when n≠n', decreasing m sequentially until n=n' is satisfied, and outputting n, m, p, q, α, θ.
[0043] In some embodiments, the parameter design method further includes: when n≠n' and m decreases to 1 without a solution, n is decreased sequentially, and the above steps are repeated until n=n' is satisfied, and n, m, p, q, α, θ are output.
[0044] In some embodiments, the parameter design method further includes: when n≠n' and there is still no solution when n is decreased to 1, resetting positive integers p and q, and repeating the above steps until n=n' is satisfied, and outputting n, m, p, q, α, θ. Attached Figure Description
[0045] Figure 1 This is a schematic diagram of a traditional micromirror array.
[0046] Figure 2 This is a schematic diagram of a traditional micro-convex mirror array.
[0047] Figure 3 A schematic diagram of a direct-write lithography system provided in an embodiment of this application;
[0048] Figure 4 This is a schematic diagram of the structure of a micromirror array provided in an embodiment of this application;
[0049] Figure 5 This is a schematic diagram of a micro-convex mirror array provided in an embodiment of this application;
[0050] Figure 6This is a schematic diagram of the structure of an exposure dot array formed by light passing through a micro-convex mirror array, provided in an embodiment of this application.
[0051] Figure 7 A schematic diagram of a structure of six micromirrors adjacent to any one micromirror, provided for an embodiment of this application;
[0052] Figure 8 A schematic diagram of a structure of six exposure points adjacent to any one exposure point, provided for an embodiment of this application;
[0053] Figure 9 This is a schematic diagram of a scanning exposure state provided in an embodiment of this application;
[0054] Figure 10 A flowchart illustrating a parameter design method for a micromirror assembly used in direct-write lithography, provided in an embodiment of this application;
[0055] Figure 11 A flowchart illustrating a parameter design method for a micromirror assembly used in direct-write lithography, provided in an embodiment of this application;
[0056] Icons: 1. Light source; 2. Micromirror array; 21. Micromirror; 3. Microconvex mirror array; 31. Microconvex mirror; 4. Stage; 5. Wafer; 6. Optical shaping device; 7. Imaging system. Detailed Implementation
[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can represent: A alone, A and B at the same time, and B alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.
[0058] The terms "first" and "second" are used for descriptive purposes only and should not be construed as implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.
[0059] Firstly, such as Figures 3-9 As shown, this application provides a direct-write lithography system, including a light source 1, a micromirror array 2, a micro-convex mirror array 3, and a stage 4 arranged sequentially.
[0060] Light source 1 is used to generate illumination light towards micromirror array 2;
[0061] The micro-mirror array 2 is used to modulate the illumination light into a target pattern beam and direct it toward the micro-convex mirror array 3;
[0062] The micro-convex mirror array 3 is used to receive the target pattern beam, process it into a focused array, and project it onto the worktable 4;
[0063] Workbench 4 is used to support wafer 5;
[0064] The number of micro-mirrors 21 in micro-mirror array 2 is the same as the number of micro-convex mirrors 31 in micro-convex mirror array 3, and their center positions correspond one-to-one.
[0065] A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either six micromirrors 21 adjacent to any one microreflector or six microconvex mirrors 31 adjacent to any one microconvex mirror.
[0066] The aforementioned direct-write lithography system uses a micromirror array 2 and a microconvex mirror array 3 to form a dynamic mask for dynamic exposure. For example... Figure 4 and Figure 5 As shown, the number of micromirrors 21 and micromirrors 31 in the micromirror array 2 and micromirror array 3 are the same, and their center positions correspond one-to-one. Their arrangement is such that the center points of any six adjacent micromirrors form a hexagon, creating a hexagonal close-packed structure with a compact design. Compared to the arrangement where the center points of adjacent micromirrors form a square, the arrangement of the micromirror array 2 and micromirror array 3 in this application increases the duty cycle (the ratio of the effective area for light transmission to the total area) by 15.4% (the duty cycle in this application is approximately 0.906, while the duty cycle in conventional technology is 0.785). In other words, during the photolithography process, the effective area for light transmission in the micromirror array 2 and micromirror array 3 increases, significantly improving the utilization rate of the light source, which is beneficial for increasing throughput and improving the production efficiency of photolithography wafers.
[0067] It should be noted that the micromirror array 2 in this application can be a DMD or other optical modulator. The micromirror unit in the micro-convex mirror array 3 can be a micro-convex lens or a micro-convex mirror. The function of the micro-convex mirror array 3 is to process the target pattern beam from the micromirror array 2 into a focused array of points to serve as the "object" in the subsequent imaging process, and after appropriate processing, to direct the beam onto the stage 4 for photolithography on the wafer.
[0068] It should be noted that, as Figure 5 and Figure 6 As shown, the dot matrix formed by the center point of the micromirror is arranged in the same way as the final exposure dot matrix, that is, the six exposure points adjacent to any one exposure point form a hexagon, wherein no three of the six adjacent exposure points are collinear. Figure 7 and Figure 8 The diagram illustrates any six adjacent micromirrors and any six adjacent exposure points. Figure 7 As shown, the center points of six micromirrors adjacent to any one micromirror form a hexagon A0B0C0D0E0F0, with the center point of the central micromirror being O0. A0B0=B0C0=D0E0=E0F0=A0O0=O0D0=a0, B0O0=C0D0=A0F0=O0E0=b≥a0, ∠B0A0D0=∠E0D0A0=α. (The rest of the text appears to be a continuation of the previous sentence and can be left as is.) Figure 8 As shown, a hexagon ABCDEF is formed by the centers of six exposure points adjacent to any given exposure point. The center point of the central exposure point is O, AB = BC = DE = EF = AO = OD = a, BO = CD = AF = OE ≥ a, and ∠BAD = ∠EDA = α. At this time, the empty space ratio of the micromirror array is π / 4sinα. When α = π / 3, corresponding to a regular hexagonal arrangement, the empty space ratio is... When α = π / 2, it corresponds to a regular quadrilateral arrangement, and the empty space ratio is π / 4 = 0.785.
[0069] Currently, images are pixelated in a quadrilateral manner. To enable the hexagonal exposure dot array formed after light passes through the micromirror array to scan and expose the quadrilateral pixelated image, this application's embodiments have designed a corresponding method, such as... Figure 9 The scanning method is shown below. Since the dot matrix formed by the center point of the micromirror is consistent with the final exposure dot matrix arrangement, the parameters of the lens array will be explained below using the scanning exposure state of the exposure dot matrix at a certain moment as an example.
[0070] Reference Figure 9The hexagon formed by connecting the center points of six micromirrors adjacent to any one of them includes micromirror 01, micromirror 02, micromirror 03, micromirror 04, micromirror 05, and micromirror 06; micromirror 01 and micromirror 02 are in the same row; micromirror 03 and micromirror 04 are in the same row; micromirror 05 and micromirror 06 are in the same row.
[0071] The distance between the center point of the first micromirror 01 and the center point of the second micromirror 02 is a0; the distance between the center point of the first micromirror 01 and the center point of the third micromirror 03 is a0; the distance between the center point of the second micromirror 02 and the center point of the fourth micromirror 04 is b; where b ≥ a0;
[0072] The angle between the line connecting the center point of the first micromirror 01 and the center point of the second micromirror 02 and the scanning direction of the direct-write lithography system is θ, that is, the direction of the row of the exposure dot matrix forms a certain angle θ with the scanning direction, 0rad<θ≤0.15rad;
[0073] The angle between the line connecting the center point of the first micromirror 01 and the center point of the second micromirror 02 and the line connecting the center point of the first micromirror 01 and the center point of the third micromirror 03 is α, where 1.04 rad ≤ α ≤ 1.57 rad.
[0074] The distance between the exposure center point formed by the first micromirror 01 and the exposure center point formed by the second micromirror 02 in the scanning direction is pd, and the distance perpendicular to the scanning direction is qd, with the most typical setting being q = 1; the distance between the exposure center point formed by the first lens 01 and the exposure center point formed by the third lens 03 in the scanning direction is md, and the distance perpendicular to the scanning direction is nd, where p, q, m, and n are all positive integers, and n < p - 1. d represents the grid period of the target exposure pattern, which is pixelated in a square manner. According to Figure 9 The geometric relationships shown above, and the parameters satisfy the following relationship:
[0075] (1) pd = acosθ;
[0076] (2) qd = asinθ;
[0077] (3) md = acos(α-θ);
[0078] (4)nd=asin(α-θ); where p, q, m, and n are all positive integers.
[0079] It should be noted that in the grid of the pixelated target exposure pattern, each row of grid points corresponds to an exposure point in this embodiment of the application. All exposure points together form an exposure dot matrix, and the direction of the rows of the exposure dot matrix is at a certain angle θ with the scanning direction, so that the hexagonal array of this embodiment of the application can adapt to the current pixelated image.
[0080] In some embodiments, such as Figure 4 As shown, the shape of each micromirror 21 in the micromirror array 2 includes, but is not limited to, a circle and a hexagon.
[0081] In some embodiments, such as Figure 5 As shown, each micro-convex mirror 31 in the micro-convex mirror array 3 is circular in shape.
[0082] In some embodiments, the direct-write lithography system further includes an absorption device (not shown in the figure), which is disposed between the micromirror array 2 and the microconvex mirror array 3;
[0083] The micro-mirror array 2 includes a first working state and a second working state; when it is in the first working state, the reflected light from the micro-mirror array 2 is directed toward the micro-convex mirror array 3; when it is in the second working state, the reflected light from the micro-mirror array 2 is absorbed by the absorption device.
[0084] One possible way to achieve this is, such as Figure 3 As shown, each micromirror 21 in the micromirror array 2 of this application has two states: "on" and "off". When the micromirror 21 is in the "on" state, the reflected light passing through the micromirror 21 can be directed to the micro-convex mirror array 3 and participate in the subsequent exposure process. When the micromirror 21 is in the "off" state, the reflected light passing through the micromirror 21 will be absorbed by the absorption device and will not be directed to the micro-convex mirror array 3 to participate in the subsequent exposure process. By adjusting the on / off state of each micromirror 21 in the micromirror array 2 (including the material and angle of the micromirror 21, etc.), a target pattern beam can be formed, realizing a dynamic exposure process.
[0085] In some embodiments, when the micromirror array 2 is in the first working state, the reflected light from any one of the micromirror 21 in the micromirror array 2 covers the corresponding micromirror 31 in the microconvex mirror array 3.
[0086] One possible way to achieve this is, such as Figure 4 and Figure 5 As shown, the micro-mirrors 21 in the micro-mirror array 2 correspond to the micro-convex mirrors 31 in the micro-convex mirror array 3, and the area of the micro-mirror 21 is larger than that of the micro-convex mirror 31. This is beneficial to ensure that all the reflected light from the micro-mirror 21 is directed to and covers the corresponding micro-convex mirror 31, thereby improving the utilization rate of the light source and increasing the total duty cycle.
[0087] In some embodiments, such as Figure 3 As shown, the direct-write lithography system also includes a light shaping device 6, which is located between the light source 1 and the micromirror array 2. The light shaping device 6 is used to process the illumination light generated by the light source 1 into parallel light. The arrangement of the light shaping device 6 facilitates the micromirror array 2 in adjusting each micromirror 21 according to the parallel beam, which is beneficial for forming the target pattern beam.
[0088] In some embodiments, the direct-write lithography system further includes an imaging system 7, which is disposed between the micro-mirror array 3 and the stage 4, and is used to process the focused dot array formed by the micro-mirror array 3 into an exposure dot array and image it onto the wafer 5 of the stage.
[0089] One possible way to achieve this is, such as Figure 3 As shown, the micro-convex mirror array 3 processes the target pattern beam into a focused array of points, which serves as the "object" of the imaging system 7. The beam is then directed by the imaging system 7 onto the wafer 5 supported by the stage 4 to form exposure points on the wafer 5 for direct writing.
[0090] In some embodiments, the wavelength of light source 1 is less than or equal to 100 nm. For example, the light source in this application embodiment can be a laser with a wavelength of 0.1 nm to 100 nm, such as 0.1 nm, 0.5 nm, 1 nm, 5 nm, 10 nm, 24 nm, 35 nm, 41 nm, 55 nm, 67 nm, 70 nm, 88 nm, 91 nm, 100 nm, and any value between two adjacent wavelengths mentioned above, without specific limitation.
[0091] It is understandable that improving resolution and reducing pattern line size is a perpetual pursuit in the field of photolithography, and reducing the wavelength of the light source in a photolithography system is one of the most effective means to improve resolution. However, when the wavelength of the light source is less than or equal to 100 nm, the light source achieves this by converting electrical energy into light energy, resulting in very low electro-optical conversion efficiency, high light source acquisition costs, and high light absorption rates by materials, leading to low effective light transmission rates. Therefore, the need to improve the utilization rate of the light source is extremely urgent. In existing technologies, the center point connection lines of micromirror units are arranged in a square shape, resulting in a low duty cycle and low effective light source utilization. The hexagonal arrangement of the center point connection lines of the micromirror units proposed in this application can significantly improve the duty cycle, thereby improving the effective utilization rate of the light source, increasing production efficiency, and reducing the light source acquisition costs.
[0092] In some embodiments, the total duty cycle of the micromirror array 2 and the microconvex mirror array 3 is 0.8-0.906. For example, the total duty cycle of this application can be 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.901, 0.903, etc., as well as any value between two adjacent values mentioned above, without any specific limitation.
[0093] Considering that the reflectivity of each micromirror 21 in different arrangement forms of micromirror array 2 is consistent, and the transmittance or reflectivity of each microconvex mirror 31 in different microconvex mirror array 3 is consistent, the transmission efficiency of light from light source 1 to imaging system 7 can be directly characterized by the duty cycle of micromirror array 2 and microconvex mirror array 3 in different arrangement forms.
[0094] like Figure 4 and Figure 5 As shown, when each micromirror 21 in the micromirror array 2 is hexagonal, its duty cycle (the ratio of the area occupied by the micromirror in the hexagon to the total area of the hexagon) can be approximated as 1 (the gap size between units is much smaller than the unit size). When each microconvex mirror 31 in the microconvex mirror array 3 is circular, its duty cycle (the ratio of the area occupied by the microconvex mirror in the hexagon to the total area of the hexagon) is... Therefore, the highest total duty cycle is 0.906. When the micromirror elements in both micromirror array 2 and microconvex mirror array 3 are circular, the duty cycles of both arrays are... The highest total duty cycle is 0.906. Understandably, depending on the actual situation, when the area of the micro-convex mirror 31 in the micro-convex mirror array 3 is slightly smaller than the area of the corresponding micro-reflector 21 in the micro-reflector array 2, the total duty cycle will decrease slightly.
[0095] Secondly, embodiments of this application also provide a micromirror assembly for direct-write lithography, such as... Figures 3-5 As shown, the micromirror assembly includes a micromirror array 2 and a micro-convex mirror array 3, which are arranged along the optical path.
[0096] The micro-mirror array 2 is used to generate a target pattern beam based on the illumination light and direct it toward the micro-convex mirror array 3;
[0097] Micro-convex mirror array 3 is used to generate a focusing array based on the target pattern beam;
[0098] The number of micro-mirrors 21 in micro-mirror array 2 is the same as the number of micro-convex mirrors 31 in micro-convex mirror array 3, and their center positions correspond one-to-one.
[0099] A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either the six micromirrors adjacent to any one microreflector or the six microconvex mirrors adjacent to any one microconvex mirror.
[0100] Thirdly, embodiments of this application provide a parameter design method for a micromirror assembly used in direct-write lithography, such as... Figure 3 As shown, the micromirror assembly includes a micromirror array 2 and a microconvex mirror array 3; as Figure 4 and Figure 5 As shown, the center points of the six micromirrors adjacent to any one micromirror form a hexagon. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either the six micromirrors 21 adjacent to any one micromirror 21 in the micromirror array 2 or the six microconvex mirrors 31 adjacent to any one microconvex mirror 31 in the microconvex mirror array 3.
[0101] like Figure 9 As shown, the hexagon formed by connecting the center points of six micromirrors adjacent to any one of them includes micromirror 01, micromirror 02, micromirror 03, micromirror 04, micromirror 05, and micromirror 06; micromirror 01 and micromirror 02 are in the same row; micromirror 03 and micromirror 04 are in the same row; micromirror 05 and micromirror 06 are in the same row.
[0102] The distance between the center point of the first micromirror 01 and the center point of the second micromirror 02 is a0; the distance between the center point of the first micromirror 01 and the center point of the third micromirror 03 is a0; the distance between the center point of the second micromirror 02 and the center point of the fourth micromirror 04 is b;
[0103] The angle between the line connecting the center point of the first micromirror 01 and the center point of the second micromirror 02 and the scanning direction of the direct-write lithography system is θ.
[0104] The angle between the line connecting the center point of the first micromirror 01 and the center point of the second micromirror 02 and the line connecting the center point of the first micromirror 01 and the center point of the third micromirror 03 is α.
[0105] The distance between the exposure center point formed by the first micromirror 01 and the exposure center point formed by the second micromirror 02 in the scanning direction is pd, and the distance perpendicular to the scanning direction is qd; the distance between the exposure center point formed by the first micromirror 01 and the exposure center point formed by the third micromirror 03 in the scanning direction is md, and the distance perpendicular to the scanning direction is nd.
[0106] like Figure 10As shown, the parameter design method of this application embodiment includes the following steps:
[0107] S1001. Given positive integers p and q, calculate θ.
[0108] S1002. Set the positive integer n to p-1, and set the positive integer m to less than p-1. Given the largest integer, calculate α and n'; where n' is calculated from q, α, and θ.
[0109] S1003. When n = n', output n, m, p, q, α, θ.
[0110] It should be noted that the above α, θ, and n' are calculated from the following relationship:
[0111] (1) pd = acosθ;
[0112] (2) qd = asinθ;
[0113] (3) md = acos(α-θ);
[0114] (4)nd=asin(α-θ);
[0115] Specifically, according to equations (1) and (2), p / q = cotθ is obtained, and θ is calculated; according to equations (3) and (4), m / n = cot(α-θ) is obtained, and α is calculated; according to equations (2) and (4), n = qsin(α-θ) / sinθ is obtained, and n' is calculated.
[0116] In some embodiments, the parameter design method further includes: when n≠n', decreasing m sequentially until n=n' is satisfied, and outputting n, m, p, q, α, θ.
[0117] In some embodiments, the parameter design method further includes: when n≠n' and m decreases to 1 without a solution, n is decreased sequentially, and the above steps are repeated until n=n' is satisfied, and n, m, p, q, α, θ are output.
[0118] In some embodiments, the parameter design method further includes: when n≠n' and there is still no solution when n is decreased to 1, resetting positive integers p and q, and repeating the above steps until n=n' is satisfied, and outputting n, m, p, q, α, θ.
[0119] It should be noted that "no solution" refers to the situation where, when m decreases to 1 or n decreases to 1, the condition n = n' is still not satisfied, meaning that the results for the parameters n, m, p, q, α, and θ cannot be output.
[0120] To make the solutions provided in the embodiments of this application easier to understand, the parameter design method for a micromirror assembly used in direct-write lithography is described in detail below through a specific embodiment. For example... Figure 11 As shown, the process includes the following steps:
[0121] S1101. Given positive integers p and q, calculate θ.
[0122] S1102. Set the positive integer n to p-1;
[0123] S1103. Determine if n is greater than 0; if yes, execute S1104; otherwise, execute S1101.
[0124] S1104. Set the positive integer m to be less than... The largest integer;
[0125] S1105. Determine if m is greater than 0; if yes, execute S1106; otherwise, execute S1110.
[0126] S1106. Calculate α and n'.
[0127] S1107. Determine whether n = n' is true; if yes, proceed to S1108; otherwise, proceed to S1109.
[0128] S1108, output n, m, p, q, α, θ.
[0129] S1109, m is decreased by 1, and S1105 is executed;
[0130] S1110, n decreases by 1, and S1103 is executed.
[0131] Table 1 shows some examples of solutions obtained in this application, wherein, Figure 9 The array parameters shown are n=7, m=4, p=8, q=1, α=1.176005207, θ=0.124354995, and the empty ratio is 0.851.
[0132] Table 1
[0133]
[0134]
[0135] As can be seen from Table 1, compared with a square lens array, the arrangement of the lens array in this embodiment can significantly improve the total duty cycle, thereby improving the utilization rate of the light source.
[0136] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A direct-write lithography system, characterized in that, It includes a light source, a micro-mirror array, a micro-convex mirror array, and a worktable arranged in sequence; The light source is used to generate illumination light toward the micro-mirror array; The micro-mirror array is used to modulate the illumination light into a target pattern beam and direct it toward the micro-convex mirror array; The micro-convex mirror array is used to receive the target pattern beam, process it into a focused array, and project it onto the worktable; The worktable is used to hold the wafer; The number of micromirrors in the micromirror array is the same as the number of microconvex mirrors in the microconvex mirror array, and their center positions correspond one-to-one. A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either six micromirrors adjacent to any one microreflector or six microconvex mirrors adjacent to any one microconvex mirror.
2. The direct-write lithography system according to claim 1, characterized in that, The hexagon formed by connecting the center points of the six micromirrors adjacent to any one of the micromirrors includes a first micromirror, a second micromirror, a third micromirror, a fourth micromirror, a fifth micromirror, and a sixth micromirror; the first micromirror is in the same row as the second micromirror; the third micromirror is in the same row as the fourth micromirror; and the fifth micromirror is in the same row as the sixth micromirror. The distance between the center point of the first micromirror and the center point of the second micromirror is a0; the distance between the center point of the first micromirror and the center point of the third micromirror is a0; the distance between the center point of the second micromirror and the center point of the fourth micromirror is b; where b ≥ a0; The angle between the line connecting the center point of the first micromirror and the center point of the second micromirror and the scanning direction of the direct-write lithography system is θ, where 0 rad < θ ≤ 0.15 rad; The angle between the line connecting the center point of the first micromirror and the center point of the second micromirror and the line connecting the center point of the first micromirror and the center point of the third micromirror is α, where 1.04 rad ≤ α ≤ 1.57 rad. The distance between the exposure center point formed by the first micromirror and the exposure center point formed by the second micromirror in the scanning direction is pd, and the distance perpendicular to the scanning direction is qd; the distance between the exposure center point formed by the first micromirror and the exposure center point formed by the third micromirror in the scanning direction is md, and the distance perpendicular to the scanning direction is nd, where p, q, m, and n are all positive integers, n < p-1, m < n / √3, and d is the grid period of the pixelated target pattern.
3. The direct-write lithography system according to claim 2, characterized in that, The shape of each micromirror in the micromirror array includes either a circle or a hexagon.
4. The direct-write lithography system according to claim 3, characterized in that, Each micro-convex mirror in the micro-convex mirror array is circular in shape.
5. The direct-write lithography system according to claim 4, characterized in that, The direct-write lithography system also includes an absorption device, which is disposed between the micro-mirror array and the micro-convex mirror array; The micromirror array includes a first working state and a second working state; when in the first working state, the reflected light from the micromirror array is directed toward the microconvex mirror array; when in the second working state, the reflected light from the micromirror array is absorbed by the absorption device.
6. The direct-write lithography system according to claim 5, characterized in that, When the micromirror array is in the first working state, the reflected light from any one of the micromirrors in the micromirror array covers the corresponding microconvex mirror in the microconvex mirror array.
7. The direct-write lithography system according to claim 6, characterized in that, The direct-write lithography system also includes a light shaping device, which is located between the light source and the micro-mirror array and is used to process the illumination light generated by the light source into parallel light.
8. The direct-write lithography system according to claim 7, characterized in that, The direct-write lithography system also includes an imaging system, which is located between the micro-convex mirror array and the stage, and is used to process the focused dot array formed by the micro-convex mirror array into an exposure dot array and image it onto the wafer of the stage.
9. The direct-write lithography system according to claim 1, characterized in that, The wavelength of the light source is less than or equal to 100 nm.
10. The direct-write lithography system according to claim 9, characterized in that, The total duty cycle of the micromirror array and the microconvex mirror array is 0.8-0.
906.
11. A micromirror assembly for direct-write lithography, characterized in that, It includes a micromirror array and a micro-convex mirror array, wherein the micromirror array and the micro-convex mirror array are arranged along the optical path; The micro-mirror array is used to generate a target pattern beam based on the illumination light and direct it toward the micro-convex mirror array; The micro-convex mirror array is used to generate a focal point array based on the target pattern beam; The number of micromirrors in the micromirror array is the same as the number of microconvex mirrors in the microconvex mirror array, and their center positions correspond one-to-one. A hexagon is formed by connecting the center points of six micromirrors adjacent to any one micromirror. Among the six adjacent micromirrors, the center points of any three micromirrors are not collinear. The six micromirrors adjacent to any one micromirror are either six micromirrors adjacent to any one microreflector or six microconvex mirrors adjacent to any one microconvex mirror.