CN116027640A - Method for improving mask-free photoetching resolution of DMD (digital micromirror device) based on displacement compensation - Google Patents
Method for improving mask-free photoetching resolution of DMD (digital micromirror device) based on displacement compensation Download PDFInfo
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Abstract
The invention discloses a method for improving the mask-free photoetching resolution of a DMD (digital device) based on displacement compensation, which comprises the steps of splitting an original digital mask layout into sub-layouts and loading the sub-layouts into a DMD chip for carrying out sub-exposure under the background of using an LED ultraviolet light source and a low-magnification projection objective lens (such as 10×), and carrying out displacement compensation of the corresponding nano-scale resolution by using a piezoelectric nano-displacement table in the exposure interval of each adjacent sub-layout, thereby ensuring the compactness and the processing efficiency of the structure of the DMD mask-free photoetching system and obviously improving the resolution of the DMD mask-free photoetching system; in addition, a light intensity distribution model of the digital mask pattern generated by the DMD chip on the photoresist after projection is established, and the displacement compensation amount and the actual processing effect of the projection lithography system can be predicted and guided.
Description
Technical Field
The invention belongs to the field of maskless projection lithography, and particularly relates to a method for improving the maskless lithography resolution of a DMD (digital micromirror device) based on displacement compensation.
Background
By virtue of the advantage of no need of complex and expensive mask plate processing, the maskless digital lithography has wide application prospect in the fields of PCB circuit manufacture, micro-optical-electro-mechanical and biological chip processing, micro-nano semiconductor device preparation and the like. In particular, digital Micromirror Device (DMD) -based step-by-step area projection lithography has attracted widespread attention because of its high efficiency, low cost characteristics.
The DMD consists of high density square micromirrors, such as 1024 x 768 integrated density of 0.7 inch DMD micromirrors, each micromirror having a side length of 13.68 μm. In order to achieve higher resolution, methods such as ultraviolet coherent light source (such as femtosecond laser light source with a center wavelength of 400 nm), high-reduction-ratio high-numerical-aperture projection objective lens, and thinner photoresist are often adopted in recent years. However, femto-second lasers are expensive and generally large in size, so that the compactness of the whole exposure system will be reduced, and at the same time, the disadvantage of the high-magnification objective lens is that the size of a single process of the exposure system is reduced (for example, the size of a 0.7-inch DMD is reduced, and after exposure by a projection system with a reduction magnification of 50×the area of the single process is only 280 μm×210 μm), so that the processing efficiency is reduced sharply. If a small ultraviolet LED incoherent light source and a low-magnification objective lens (such as a 10X objective lens) are used, the processing efficiency is relatively high (the area of single processing is larger than 1 mm) 2 Etc.), but the resolution of the processing is difficult to break through by 1 μm.
It is noted that the displacement system is used as a core component of the maskless projection lithography system, and the resolution thereof can be from 1nm to tens of μm according to different resolutions of the selected hardware, so that the high resolution of the displacement system can be utilized to make up for the shortage of the resolution of the DMD maskless lithography system as long as a displacement table with high resolution is selected. Based on the above analysis, the present invention proposes a method for realizing sub-micron resolution of DMD maskless lithography using a high resolution displacement stage, such as a piezoelectric nano displacement stage.
Disclosure of Invention
The invention provides a method for improving the resolution of DMD maskless lithography based on displacement compensation, which aims to realize the submicron processing resolution of the DMD maskless lithography system under the background of applying a small ultraviolet LED incoherent light source and a low-magnification objective (such as a 10 multiplied by the objective).
The invention aims to solve the technical problems, and the technical scheme of the invention is as follows:
firstly, a maskless lithography system for improving the maskless lithography resolution of a DMD based on displacement compensation comprises a small ultraviolet LED light source, a uniform light shaping collimation module, an optical switch, a DMD chip, a sleeve lens, an objective lens, photoresist, a substrate, a computer and a piezoelectric nano displacement table; the computer is used for controlling the optical switch, the DMD chip and the piezoelectric nano displacement table; the small ultraviolet LED light source is used for generating incoherent ultraviolet light, and the incoherent ultraviolet light passes through the uniform light shaping collimation module to form uniformly collimated rectangular ultraviolet light spots, so that the imaging quality of the system is improved; the optical switch is used for accurately controlling the exposure time of the system; the DMD is used for generating a programmable pixelated digital mask pattern, the digital mask pattern is reduced according to corresponding proportion after passing through the sleeve lens and the objective lens and projected onto the surface of the photoresist for exposure, and the photoresist is coated on the substrate; the sleeve lens and the objective lens are also referred to as a projection miniature assembly; the piezoelectric nano displacement platform is used for realizing the movement of the nano resolution.
In the scheme, the DMD chip, the sleeve lens, the objective lens and the photoresist are corrected according to the infinity conjugated system, and on the premise of ensuring the reduction ratio, the optical element is increased or decreased between the sleeve lens and the objective lens without changing the imaging quality of the digital mask pattern.
Secondly, a method for improving the maskless photoetching resolution of the DMD based on displacement compensation comprises the following steps: s1: splitting a digital mask layout at the processing limit of the DMD maskless lithography system into a left digital mask sub-layout (hereinafter referred to as left sub-layout) and a right digital mask sub-layout (hereinafter referred to as right sub-layout) by using a computer; s2: loading the left sub-layout into a DMD chip through a computer, and controlling the switch of the corresponding micro mirror; s3: turning on an optical switch, irradiating rectangular incoherent ultraviolet light spots after uniform light shaping and collimation on the DMD, reflecting by corresponding micromirrors on the DMD to form corresponding digital mask patterns, and projecting the digital mask patterns on photoresist on a substrate for first exposure after the formed digital mask patterns are reduced by a projection miniature assembly; s4: the piezoelectric nano displacement table is controlled by a computer to move rightward by a compensation distance delta L; s5: loading the right sub-layout into the DMD chip through a computer, controlling the switch of the corresponding micro mirror, and repeating the step S3 to perform the second exposure; s6: and developing to finally obtain a processing pattern with improved resolution on the photoresist.
In the above scheme, the content, style, layout direction and splitting manner of the digital mask layout at the processing limit of the DMD maskless lithography system in step S1 are only for more clearly explaining the principle of the scheme, and are not limited to the content, style, layout direction and splitting manner of the digital mask layout.
In the above scheme, the number of channel pixels between the left sub-layout and the right sub-layout in the digital mask layout at the processing limit of the DMD maskless lithography system is P, and the channel size in the digital mask pattern generated on the DMD is: p x D (D is the side length of a single square micromirror of DMD); exposing the left sub-layout and the right sub-layout simultaneously, and obtaining a first processing size L on the photoresist after the channel size is scaled by a projection micro component 0 The method comprises the steps of carrying out a first treatment on the surface of the After the steps S1 to S6 are performed, the channel size of the processing pattern with improved resolution is the second processing size L.
Preferably, the first processing dimension is L for the number P of channel pixels, the compensation distance DeltaL 0 And a second processing dimension L, for performing modeling analysis on the light intensity distribution of the digital mask pattern generated by the DMD in the step S3 formed on the photoresist by the projection micro assembly, and for simplicity, considering that the digital mask pattern generated by the DMD has strict pixel periodicity, performing modeling analysis on the light intensity distribution of the single micromirror facing the DMD on the photoresist:
considering that the single-side size of a single DMD micro-mirror on a photoresist is only 1 to 3 mu m after the single-DMD micro-mirror is reduced by a low-magnification projection micro-system, and the single-DMD micro-mirror is imaged on the photoresist to be imaged at the infinity after the projection micro-system is subjected to the conjugate correction of the infinity, the light intensity distribution model of the single-DMD micro-mirror on the photoresist can be approximately regarded as a Fraunhofer Fei Juxing hole diffraction model:
wherein ,
wherein ,I0 The method comprises the steps that (1) a, b are the length and the width of an equivalent image of a single DMD micro-mirror at an entrance pupil of an objective lens, lambda is the central wavelength of an ultraviolet LED light source, f is the focal length of the objective lens, (x, y) is coordinate information of the photoresist, (m, n) is position information of the single DMD micro-mirror on the photoresist after being reduced by a projection micro-assembly, and d is the center distance of imaging on the photoresist after two adjacent micro-mirrors of the DMD chip are reduced by the micro-projection assembly;
briefly, since the ultraviolet LED light source used by the maskless lithography system is an incoherent light source, the light intensity distribution of the digital mask pattern generated by a plurality of micromirrors on the DMD on the photoresist can be considered approximately as a superposition of the light intensity distribution of each micromirror on the photoresist:
the experimental verification proves that the simulation result of the light intensity distribution model is very matched with experimental data, and the simulation result can be used for predicting and controlling the actual processing effect of the maskless photoetching system so as to guide the acquisition of the processing pattern with improved resolution on the photoresist.
Preferably, the zoom ratio of the projection micro system in the step S3 is 9/100, wherein the focal length of the sleeve lens is 200mm, and the focal length of the objective lens is f=18 mm.
Preferably, the photoresist in the step S3 is a high resolution photoresist, and the resolution thereof is a limit resolution that can be processed by the maskless lithography system.
Preferably, the resolution of the piezoelectric nano-displacement stage in the step S4 is 1nm, so as to control the accuracy of the compensation distance Δl in the step S4 to be in the nano-scale.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
the invention can enable the maskless lithography system to simultaneously have the following advantages: 1) The light source is a small ultraviolet LED incoherent light source, so that the compactness of the maskless lithography system structure is ensured; 2) The projection objective is low-magnification objective (such as 10×objective), and can realize single processing with area not less than 1mm 2 The processing efficiency of the maskless lithography system is ensured; 3) On the basis of 1) and 2), a light intensity distribution model of a digital mask pattern generated for the DMD is established, and under the guidance of the light intensity distribution model, the processing resolution of the maskless lithography system can be controlled at submicron level (the ultimate processing resolution which can be realized theoretically is the resolution of the photoresist used) by applying the compensation distance delta L with nanometer-level precision through the piezoelectric nanometer displacement table only in the interval of two exposures.
Description of the drawings:
FIG. 1 is a schematic diagram of the system;
FIG. 2 is a digital mask layout of the system process limits;
FIG. 3 is a schematic diagram of the method;
FIG. 4 is a light intensity distribution of a single pixel line on the photoresist in simulation experiment 1;
FIG. 5 is a graph showing the light intensity distribution of lines of different pixel widths on the photoresist in simulation experiment 2;
FIG. 6 is a graph showing the light intensity distribution of an exposure pattern on the photoresist at different displacement compensation amounts in simulation experiment 3;
FIG. 7 shows the channel profile of the exposure pattern processed by the system at different displacement offsets in exposure experiment 1;
wherein the reference numerals in fig. 3: 8-photoresist; 9-substrate; 10-piezoelectric nano displacement table; 15-the left sub-layout is exposed on the photoresist; the exposure position of the right sub-layout on the photoresist is 16-when the displacement compensation quantity is not 0; 17-the exposure position of the right sub-layout on the photoresist when the displacement compensation quantity is 0; 18-displacement compensation quantity;
wherein the exposure pattern and the displacement compensation direction shown in fig. 3 are only more visual for showing the method, and are not included in the protection of the present invention;
wherein the reference numerals in fig. 5: 21-31 sequentially represent the light intensity distribution of lines with the pixel widths of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11 on the photoresist;
wherein the reference numerals in fig. 6: 32-38 represent the light intensity distribution of the exposure pattern on the photoresist at 0 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm, respectively, under the displacement compensation amount in order;
wherein the reference numerals in fig. 7: 39-44 show the channel morphology (scanning electron microscope (SEM) shooting) of the exposure patterns processed by the system when the displacement compensation amounts are respectively 0 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm and 1.2 μm;
the specific embodiment is as follows:
in order that the above-recited objects, features and advantages of the present invention will be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in fig. 1, a maskless lithography system for improving the maskless lithography resolution of a DMD based on displacement compensation comprises a small ultraviolet LED light source (1), a dodging collimation module (2), an optical switch (3), a DMD chip (4), a stray light absorbing medium (5), a sleeve lens (6), an objective lens (7), a photoresist (8), a substrate (9), a piezoelectric nano displacement table (10) and a computer (11); the computer (11) is used for controlling the optical switch (3), the DMD chip (4) and the piezoelectric nano displacement platform (10); the small ultraviolet LED light source (1) is used for generating incoherent ultraviolet light with the center wavelength of 405nm, and the incoherent ultraviolet light passes through the uniform-light shaping collimation module (2) to form uniformly collimated rectangular ultraviolet light spots, so that the imaging quality of the system is improved; the dodging and shaping collimation module (2) utilizes a fly-eye lens in a rectangular form to realize dodging and shaping effects on incident incoherent ultraviolet light; the optical switch (3) is used for accurately controlling the exposure time of the system, and the control precision is 0.1S; the DMD chip (4) is a 0.7-inch DMD, the integration density of micro mirrors is 1024 multiplied by 768, the size of a single micro mirror is 13.68 multiplied by 13.68 mu m, the single micro mirror is used for generating a programmable pixelated digital mask pattern, the digital mask pattern is reduced according to corresponding proportion after passing through the sleeve lens (6) and the objective lens (7) and projected onto the surface of the photoresist (8) for exposure, and the photoresist (8) is coated on the substrate (9), and the resolution ratio of the digital mask pattern is 0.5 mu m; the sleeve lens (6) and the objective lens (7) are also called a projection micro-assembly, the sleeve lens (6) and the objective lens (7) are subjected to infinite conjugate correction with the DMD chip (4) and the photoresist (8), on the premise of ensuring the reduction ratio, the imaging quality of an optical element is increased or decreased between the sleeve lens (6) and the objective lens (7) without changing the digital mask pattern, the focal length of the sleeve lens (6) is 200mm, the focal length of the objective lens (7) is 18mm, namely the actual scaling ratio of the projection micro-assembly is 9/100, namely the center distance of imaging on the photoresist (8) is 13.68 mu m/100 multiplied by 9 approximately 1.23 mu m after the two adjacent micro-mirrors of the DMD chip (4) are reduced by the micro-projection assembly, and the fact that the actual center distance is approximately d=1.2 mu m is remarkable because unavoidable errors exist in the system assembly process; the piezoelectric nano displacement stage (10) is used for nano resolution movement.
Further, a method for improving the maskless photoetching resolution of the DMD based on displacement compensation comprises the following steps:
s1: splitting a digital mask layout at the processing limit of the DMD maskless lithography system into a left digital mask sub-layout (12) (hereinafter referred to as left sub-layout) and a right digital mask sub-layout (13) (hereinafter referred to as right sub-layout) by using a computer (11); s2: loading the left sub-layout (12) into the DMD chip (4) through a computer (11) to control the switch of the corresponding micro mirror; s3: the optical switch (3) is turned on, rectangular incoherent ultraviolet light spots after uniform light shaping and collimation are irradiated on the DMD (4), corresponding digital mask patterns are formed after being reflected by corresponding micromirrors on the DMD (4), and the formed digital mask patterns are projected on the photoresist (8) on the substrate (9) for first exposure (15) after being reduced by the projection miniature assemblies (6 and 7); s4: controlling the piezoelectric nano displacement table (10) to move rightward by a compensation distance delta L (18) through a computer (11); s5: loading the right sub-layout (13) into the DMD chip (4) through a computer, controlling the switch of the corresponding micro mirror, and repeating the step S3 to perform the second exposure (16); s6: developing, and finally obtaining a processed pattern with improved resolution on the photoresist (8).
It should be noted that the content, style, layout direction and splitting manner of the digital mask layout (as shown in fig. 2) at the processing limit of the DMD maskless lithography system in the step S1 are merely for more clearly explaining the principle of the scheme, and are not limited to the content, style, layout direction and splitting manner of the digital mask layout.
In the above scheme, the number of pixels of the channel (14) between the left sub-layout (12) and the right sub-layout (13) in the digital mask layout at the processing limit of the DMD maskless lithography system is P, and the size of the channel in the digital mask pattern generated on the DMD (4) is: p x D (D is the side length of a single square micromirror of DMD); exposing the left sub-layout (12) and the right sub-layout (13) simultaneously, and obtaining a first processing size L on the photoresist (8) after the groove size is scaled by the projection miniature assemblies (6, 7) 0 The method comprises the steps of carrying out a first treatment on the surface of the After the steps S1 to S6 are performed, the channel size of the processing pattern with improved resolution is the second processing size L.
Further, the number of pixels P, the compensation distance DeltaL (18) and the first processing size L are the same for the channel (14) 0 And a second process dimension L, for modeling analysis of the light intensity distribution of the digital mask pattern generated by the DMD (4) on the photoresist (7) through the projection micro-assembly (6, 7), in a simplified manner, considering that the digital mask pattern generated by the DMD has a strict pixel periodicity, the modeling analysis is performed on the light intensity distribution of the single micromirror facing the DMD (4) on the photoresist (8):
further, considering that the single-side size of the single DMD (4) micromirror on the photoresist (8) is only 1 to 3 μm after the single-DMD (4) micromirror is reduced by the low-magnification projection micro-system (6, 7), and the projection micro-system (6, 7) is subjected to infinity conjugate correction, the imaging of the single-DMD (4) micromirror on the photoresist (8) is the imaging of infinity thereof, the light intensity distribution model of the single-DMD (4) micromirror on the photoresist (8) can be approximately regarded as fraunhofer Fei Juxing hole diffraction model:
wherein ,
wherein ,I0 The method comprises the steps that (1) normalized light intensity values of light intensity distribution of a single DMD (4) micro mirror on a photoresist (8), a and b are the length and width of an equivalent image of the single DMD (4) micro mirror at an entrance pupil of an objective lens (7), lambda is the center wavelength 405nm of an ultraviolet LED light source (1), f=18 mm is the focal length of the objective lens (7), (x, y) is coordinate information on the photoresist (8), and (m, n) is position information of the DMD (4) micro mirror on the photoresist (8) after being reduced by a projection micro component (6, 7), and d is the center distance of imaging on the photoresist (8) after two adjacent micro mirrors of the DMD chip (4) are reduced by a micro projection component;
briefly, since the ultraviolet LED light source (1) used in the maskless lithography system is an incoherent light source, the light intensity distribution of a digital mask pattern generated by a plurality of micromirrors in succession on the DMD (4) on the photoresist (8) can be considered approximately as a superposition of the light intensity distribution of each micromirror on the photoresist (8):
wherein M and N are the total number of micromirrors of the DMD (4) in the x and y directions.
In order to more intuitively embody the actual effect of the technical solution and embody the guidance of the light intensity distribution model, an embodiment is described below.
In this embodiment, in consideration of symmetry of the dimensions of the square micromirrors of the DMD (4), the simulation results of pattern exposure imaging in the x-axis and y-axis directions are uniform, and the simulation results of the exposure pattern in the x-axis direction are taken as the analysis objects without losing generality.
In this embodiment, to determine the exposure threshold (19) of the photoresist (8), a simulation experiment 1 is designed:
as shown in fig. 4, the simulation result of the light intensity distribution on the resist (8) after the exposure of the single pixel line (the line direction is the y-axis direction) (the experimental data is based on the condition that the peak light intensity of the exposure of the single pixel line is normalized), wherein the portion of the relative light intensity above the resist exposure threshold (19), i.e., the simulated line width corresponding to the developed single pixel line, is 1.6 μm, which is very close to the actual line width 1.61 μm obtained in the actual single pixel exposure test (the actual processed single pixel line width map (20) is photographed by a Scanning Electron Microscope (SEM), and the white scale in the map represents 1 μm), thus determining that the resist exposure threshold (19) is 0.8 of the relative light intensity in the present embodiment.
Further, in this embodiment, in order to determine the influence of the number of exposure pixels in the x-axis direction on the processing line width in the x-axis direction, simulation experiment 2 was designed:
as shown in fig. 5, the simulation experiment 2 was analyzed by a simulation result of exposing lines of different pixel widths in the x-axis direction (the line direction is the y-axis direction). It can be found that when the number of pixels in the x-axis direction is greater than or equal to 3, the simulated line width corresponding to the exposure line at the photoresist exposure threshold (19) is linearly increased along with the increase of the number of pixels, and the increment is the center distance d of imaging on the photoresist (8) after the two adjacent micromirrors of the DMD chip (4) are reduced by the miniature projection component.
Further, in this embodiment, in order to embody the guidance of the model, simulation analysis is performed on the exposure experiments in the above steps S1 to S6, and a simulation experiment 3 is designed:
in order to avoid losing generality, as can be seen from analysis of fig. 5, in this embodiment, the number of pixels in the x-axis direction of the left sub-layout (12) and the right sub-layout (13) is more than or equal to 3, and when the number of pixels p=1 or p=2 of the channel (14) between the left sub-layout (12) and the right sub-layout (13) is shown by model prediction, the theoretical line width of the exposed channel (14) is lower than the resolution of the photoresist (8) by 0.5 μm, which accords with the actual experimental data (i.e. after actual processing, the channel area disappears), based on the above analysis, the embodiment selects the number of pixels in the x-axis direction of the left sub-layout (12) and the right sub-layout (13) to be 9, and when the compensation distance Δl (18) is 0, the simulation result of the exposed line width at the developed channel is shown to be 2.2 μm;
further, simulation experiment 3 devised a series of compensation distances Δl (18) of 0 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm in this order (the value of the compensation distance Δl (18) corresponds to the number of pixels p=2 of the channel (14), so that it is not necessary to continue to increase the compensation distance Δl (18)), to predict that the line width resolution at the channel can be lower than 1 μm during actual processing when the compensation distance Δl (18) is larger than a few, and to realize sub-micron processing. As shown in fig. 6, when the compensation distance Δl (18) is 0 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm in this order, the line width simulation values corresponding to the channels after development are 2.2 μm, 2.0 μm, 1.8 μm, 1.6 μm, 1.3 μm, 0.96 μm, 0.32 μm (lower than the resolution of the photoresist (8), so that the line width corresponding to the actual exposure experiment is 0 μm), and from the simulation results, when the compensation distance Δl (18) is greater than 1 μm, the line width resolution at the channels during actual processing can be lower than 1 μm, and submicron-order processing can be realized.
Further, in order to illustrate the practical effect of the technical scheme on the improvement of the processing resolution, the embodiment carries out the exposure experiment 1 according to the steps S1-S6 according to the instruction of the simulation experiment 3:
as shown in fig. 7, the experimental groups corresponding to the compensation distances Δl (18) were 0 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm in this order, and the experimental values of the line widths corresponding to the channels after development were 2.3 μm, 1.96 μm, 1.82 μm, 1.6 μm, 1.2 μm, 0.81 μm, 0 μm, respectively.
From the data results of the above exposure experiments: 1) The exposure experiment result is quite identical with the simulation result of the simulation experiment 3, and the light intensity distribution model has the guiding function on the maskless lithography system; 2) It can be found that, in this technical solution, when the compensation distance Δl (18) is small (for this embodiment, that is, Δl (18). Ltoreq.0.6 μm), the minimum line width that can be processed by the maskless lithography system decreases linearly with the increase of the compensation distance Δl (18), and when the compensation distance Δl (18) is large (for this embodiment, that is, Δl (18). Ltoreq.0.8 μm), the trend of decreasing is more remarkable with the increase of the compensation distance Δl (18). 3) It can be stated that, based on the present method, the processing resolution of the maskless lithography system can be increased to sub-micrometer level, and theoretically, the processing resolution of the maskless lithography system can reach the resolution (0.5 μm) of the photoresist (8).
The same or similar reference numerals correspond to the same or similar components.
It should be apparent that the foregoing examples of the present invention are merely illustrative of the present invention and are not intended to limit the embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. that comes within the spirit and principle of the present invention should be included in the protection scope of the present claims.
Claims (3)
1. A method for improving the maskless lithography resolution of a DMD based on displacement compensation, comprising the steps of:
s1: splitting a digital mask layout at the processing limit of the DMD maskless lithography system into a left digital mask sub-layout (hereinafter referred to as left sub-layout) and a right digital mask sub-layout (hereinafter referred to as right sub-layout) by using a computer;
s2: loading the left sub-layout into a DMD chip through a computer, and controlling the switch of the corresponding micro mirror;
s3: turning on an optical switch, irradiating rectangular incoherent ultraviolet light spots after uniform light shaping and collimation on the DMD, generating corresponding digital mask patterns after reflection by corresponding micromirrors on the DMD, and projecting the generated digital mask patterns on photoresist on a substrate after the generated digital mask patterns are reduced by a sleeve lens and an objective lens, and performing first exposure;
s4: the piezoelectric nano displacement table is controlled by a computer to move rightward by a compensation distance delta L;
s5: loading the right sub-layout into the DMD chip through a computer, controlling the switch of the corresponding micro mirror, and repeating the step S3 to perform the second exposure;
s6: and developing to finally obtain the processing pattern with improved resolution on the photoresist.
In the step S1, the content, style, layout direction and splitting manner of the digital mask layout at the processing limit of the DMD maskless lithography system are only for more clearly explaining the principle of the method, and are not limited to the content, style, layout direction and splitting manner.
2. The method for improving the resolution of DMD maskless lithography based on displacement compensation of claim 1, wherein the light intensity distribution of any pixel point in the digital mask pattern generated by the DMD chip in step S3 after the pixel point is reduced by the sleeve lens and the objective lens is:
wherein ,
wherein ,I0 The normalized intensity value of the light intensity distribution of the single DMD micromirror on the photoresist, a, b is the length and width of the equivalent image of the single DMD micromirror at the entrance pupil of the objective lens, λ is the center wavelength of the ultraviolet LED light source, f is the focal length of the objective lens, (x, y) is the coordinate information on the photoresist, (m,n) is the position information of a single DMD micro-mirror on the photoresist after being reduced by a projection micro-assembly, and d is the center distance of imaging on the photoresist after two adjacent micro-mirrors of the DMD chip are reduced by the micro-projection assembly;
the DMD maskless lithography system in step S1 uses an incoherent light source, so that the digital mask pattern generated by a plurality of micromirrors on the DMD chip can be considered, and the light intensity distribution on the photoresist can be approximately considered as the direct superposition of the light intensity distribution of each micromirror on the photoresist, namely:
wherein M and N are the total number of micromirrors of the DMD in the x and y directions.
3. The method for improving the resolution of the maskless DMD lithography based on displacement compensation of claim 1, wherein the photoresist in the step S3 is a high-resolution positive photoresist or a high-resolution negative photoresist, wherein the photoresist resolution is less than 1 μm, and the submicron processing resolution of the maskless DMD lithography system is ensured.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101317133A (en) * | 2005-05-02 | 2008-12-03 | 拉多韦有限公司 | Lithographic method for maskless pattern transfer onto a photosensitive substrate |
| CN111580346A (en) * | 2020-05-21 | 2020-08-25 | 吉林大学 | Method for measuring and correcting inclination angle and magnification in DMD photoetching system |
| CN112596348A (en) * | 2020-12-16 | 2021-04-02 | 暨南大学 | System and method for improving projection lithography resolution based on phase modulation |
| CN112596347A (en) * | 2020-12-16 | 2021-04-02 | 暨南大学 | Multiple exposure method for digital mask projection photoetching |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101317133A (en) * | 2005-05-02 | 2008-12-03 | 拉多韦有限公司 | Lithographic method for maskless pattern transfer onto a photosensitive substrate |
| CN111580346A (en) * | 2020-05-21 | 2020-08-25 | 吉林大学 | Method for measuring and correcting inclination angle and magnification in DMD photoetching system |
| CN112596348A (en) * | 2020-12-16 | 2021-04-02 | 暨南大学 | System and method for improving projection lithography resolution based on phase modulation |
| CN112596347A (en) * | 2020-12-16 | 2021-04-02 | 暨南大学 | Multiple exposure method for digital mask projection photoetching |
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|---|---|---|---|---|
| CN117539112A (en) * | 2024-01-09 | 2024-02-09 | 之江实验室 | Refined digital imitation body projection device and projection method |
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