Efficient method for Manhattan layout e-beam lithography energy deposition density distribution calculation

Abstract

A high-efficiency method for Manhattan layout electron beam lithography energy deposition density distribution calculation. The present application is a layered electron beam lithography proximity effect correction layout energy deposition calculation method based on layout cracking. The method cracks the original layout into disjoint rectangles, calculates the electron beam lithography proximity effect energy deposition layer by layer under the premise of ensuring accuracy, greatly reduces the demand for computing resources in the electron beam lithography proximity effect correction process, and finally improves the efficiency of electron beam lithography proximity effect correction. The present application is divided into five steps: step S1 Manhattan exposure layout reading; step S2 cracking Manhattan layout into rectangles; step S3 layered calculation of electron beam lithography energy deposition density distribution, the electron beam lithography energy deposition density distribution is divided into the sum of the electron beam lithography front scattering energy deposition density distribution and the electron beam lithography back scattering energy deposition density distribution; step S4 development and measurement of mean error; step S5 update of rectangular exposure dose.

Description

Technical Field

[0001] This invention presents an efficient method for calculating the energy deposition density distribution in Manhattan lithography electron beam lithography. This method breaks down the original layout into non-intersecting rectangles and calculates the energy deposition of the proximity effect in electron beam lithography layer by layer while maintaining accuracy. This significantly reduces the computational resource requirements during the proximity effect correction process in electron beam lithography, offering high scalability and characterized by high computational accuracy and efficiency, thus belonging to the field of computational lithography. Background Technology

[0002] Electron beam lithography (EBL) is a high-resolution lithography technique with sub-10 nm resolution. EBL is widely used in cutting-edge physics research (e.g., quantum physics, superconductivity), biology (e.g., gene sequencing, molecular detection, micro / nanofluidics), microelectronics (e.g., microelectronic devices, sensors), photonics (e.g., optical waveguides, micro / nano optics), microelectromechanical systems (MEMS), and new materials—research fields involving nanotechnology. According to the matter wave theory, higher energy corresponds to shorter wavelengths; therefore, for very high-energy electron beams, the wavelength is extremely short, sometimes as low as [insert wavelength here]. Therefore, unlike optical lithography, the diffraction effect has a very small impact on electron beam lithography, which can be ignored. As a result, electron beam lithography has extremely high resolution, enabling nanometer-level exposure. For this reason, EBL is often used to manufacture high-precision masks for deep ultraviolet (DUV) and extreme ultraviolet (EUV) lithography.

[0003] Although electrons exhibit weak wave-like properties, they possess considerable particle-like characteristics. During electron beam lithography, incident electrons collide with atoms and extranuclear electrons in the photoresist and substrate, altering their ideal trajectories and causing scattering within the photoresist and substrate. This scattering leads to discrepancies between the energy deposition intensity in the photoresist and the expected intensity, resulting in an inconsistency between the final exposed pattern and the target layout. This severely impacts the actual resolution of electron beam lithography, a phenomenon known as the proximity effect (PE) generated during electron beam lithography.

[0004] Electron beam lithography proximity effect correction (PEC) uses computer simulation of the electron beam lithography exposure process and performs PEC to improve the resolution of the EBL process and the success rate of lithography results.

[0005] Electron beam lithography simulation and optimization can significantly shorten integrated circuit manufacturing time, eliminate manufacturing errors, reduce manufacturing costs, and improve lithography quality. However, as layouts become larger and feature sizes become smaller, the computational and memory requirements for full-layout pixel-based electron beam simulation increase dramatically. Due to the limited computing power and memory of a single computer, it can only meet the requirements for proximity effect correction for large-exposure layouts, thus limiting its application to proximity effect correction for small-sized layouts. To address the memory bottleneck in full-layout pixel-based electron beam lithography simulation, this invention proposes an efficient method for calculating the energy deposition density distribution of electron beam lithography in Manhattan layouts. This method is based on decomposing the layout into a union of non-intersecting rectangles. While maintaining accuracy, it calculates the proximity effect energy deposition of electron beam lithography layer by layer, greatly reducing the computational resource requirements during proximity effect correction. It is highly scalable and features high computational accuracy and efficiency. Summary of the Invention

[0006] This invention presents an efficient method for calculating the energy deposition density distribution of electron beam lithography (EBL) patterns in Manhattan lithography. The aim is to overcome the memory bottleneck of a single computer by employing pattern fragmentation and layered calculations, while maintaining accuracy. This significantly reduces the storage space required for EBL proximity correction and expands the processable pattern size.

[0007] The technical solution of this invention is as follows: Based on layout fragmentation and layered calculation, the original layout is divided into non-intersecting rectangles, each rectangle is assigned an exposure dose, and under the premise of ensuring preset accuracy, the contributions of forward scattering and backscattering in the proximity effect of electron beam lithography to the final energy deposition value are calculated layer by layer. The exposure dose of the rectangles is adjusted according to the simulated energy deposition results, and finally the proximity effect correction of the layout is completed. The steps of the invention are as follows:

[0008] Step S1: Import Manhattan exposure map;

[0009] Read in the electron beam lithography Manhattan pattern and save it as multiple polygons.

[0010] Step S2: Split the Manhattan map into a rectangle;

[0011] Cover a single polygon with a square grid of side length w nm, such as Figure 2 As shown. The square grid intersecting the polygon edges is clipped into a rectangle. Figure 3 (a) is Figure 2 A magnified view of the dashed box in the image. Figure 3 (b) is Figure 3(a) The resulting rectangular mesh after clipping remains unchanged in subsequent processing. Merging the square meshes with a side length of w nm in the middle of the polygon creates a new square mesh with a side length of 2w nm. This merging process continues until the side length of all surrounding meshes is no greater than half that of the new mesh, at which point merging stops. The final result of polygon fragmentation is as follows: Figure 4 As shown.

[0012] Step S3: Calculate the energy deposition density distribution of electron beam lithography layer by layer;

[0013] The point spread function (PSF) of electron beam lithography can be fitted by a double Gaussian function, expressed as:

[0014]

[0015]

[0016] In the formula, the physical parameter α is the forward scattering range, β is the backscattering range, η is the ratio of forward scattering to backscattering energy, K is a constant, x in formula (1) is the distance from the exposure point, and x in formula (2) is the distance from the exposure point. 2 +y 2 It is the square of the distance from the exposure point in two dimensions.

[0017] The total exposure energy deposition E(x0,y0) at the exposure point (x0,y0) is expressed as:

[0018] E(x0,y0)=∫∫PSF(x-x0,y-y0)σ(x,y)dxdy (3)

[0019] In the formula, let the dose distribution of the pattern be σ(x,y), and the integration region be the entire exposure pattern.

[0020] Since the PSF is a sum of Gaussian functions, a physical fact is that the forward scattering parameter α in the PSF is typically on the order of 10 nm, while the backscattering parameter β is typically between 1 μm and 50 μm. The ranges of forward and backscattering differ significantly, and the corresponding calculation requirements also differ. Therefore, the contributions of forward and backscattering to the total exposure energy deposition E(x0,y0) can be calculated in layers.

[0021] S3.1 Backscattered energy deposition calculation, the backscattered energy deposition calculation process is as follows: Figure 5As shown in the diagram. First, the layout is divided into multiple square sub-layout regions based on the backscattering parameter β in the PSF. Then, the layout density D within each sub-layout is calculated. Next, the convolution of the layout density D of the sub-layout with the PSF is calculated to obtain the contribution of electron backscattering to the energy deposition at the center of each sub-layout. Finally, for any non-center location of the sub-layout, i.e., any location on the layout, the contribution of electron backscattering to its energy deposition can be obtained through interpolation. A schematic diagram of the backscattering energy deposition calculation is shown below. Figure 6 As shown.

[0022] S3.2 Forward scattering energy deposition calculation: When we only consider forward scattering, point (i,j) is the location where energy deposition needs to be calculated. Points (x1,y1) and (x2,y2) are the lower left and upper right vertices of the rectangle, respectively, and σ is the exposure dose of this rectangle. The contribution of the rectangular exposure to the forward scattering energy deposition at point (i,j) is calculated as shown in Equation (4).

[0023]

[0024] For (4) substitution, let:

[0025]

[0026] After substitution and simplification, and using the standard normal cumulative function, we get:

[0027]

[0028] Where Φ(·) is the cumulative distribution function of the standard normal distribution.

[0029] The Cumulative Distribution Function (CDF) is the contribution of an exposure rectangle with an exposure dose of (0,0) as its lower left vertex and (x,y) as its upper right vertex to the forward scattering energy deposition density distribution at the origin (0,0). Figure 7 As shown in (a), it is easy to obtain from equation (6) that...

[0030]

[0031] like Figure 7 As shown in (b), the contribution v of any exposure rectangle A with unit exposure doses at the lower left and upper right vertices of the rectangle (x1,y1) and (x2,y2) respectively, to the forward scattering energy deposition density distribution at the origin (0,0) is given by:

[0032] v=CDF(x2,y2)-CDF(x1,y2)-CDF(x2,y2)+CDF(x2,y2) (8)

[0033] Since equations (7) and (8) have linear translation invariance, for any rectangle and any location of the energy deposition density to be determined, equation (8) can be obtained through coordinate linear transformation. Thus, a CDF table can be obtained first for quick reference during calculation.

[0034] The flowchart of the forward scattering energy deposition calculation is as follows: Figure 8 As shown. First, the rectangle obtained after polygon fragmentation constructs an R-tree to facilitate searching for all pattern exposure shapes within the neighborhood when calculating the forward scattering energy deposition at any point. Then, the location where the energy deposition is to be calculated is selected; this location becomes the evaluation point. Third, the R-tree queries all pattern exposure shapes within the neighborhood of the evaluation point (a rectangular area with a side length of 6α centered on the evaluation point), such as... Figure 9 As shown, the shaded area is a square grid, and its adjacent areas are square areas as indicated by dashed lines. Finally, according to equation (8), as... Figure 10 As shown, the value of the forward scattering of the map exposure shape in the vicinity at the evaluation point is obtained by several additions and subtractions.

[0035] Step S4: Error between development and measurement mean;

[0036] After the layout energy deposition calculation is completed, the actual exposed layout shape can be obtained through development. The threshold development model used in this invention is expressed as follows:

[0037]

[0038] In the formula, E thr H(x,y) is the development threshold related to substrate solubility, and H(x,y) is the pattern shape after development.

[0039] The quality of the developed pattern can be measured by the mean-square error (MSE) of the target exposed shape of the pattern, expressed as:

[0040]

[0041] In the formula, N is the number of exposure points of the layout, and L(x,y) is the target exposure shape of the layout.

[0042] Step S5: Update the rectangular exposure dose.

[0043] When the MSE in step S4 is less than the preset error limit ∈, PEC is completed, and the algorithm proposed in this invention ends. Otherwise, the dose is updated, and steps S3 to S5 are iterated until the MSE meets the requirements. The dose update is expressed as:

[0044]

[0045] In the formula, σ kD is the exposure dose of the exposure rectangle in the k-th iteration, E is the energy deposition density at the center of the exposure rectangle, and D is the energy density at the center of the exposure rectangle. T It is the preset target energy deposition value for the map. Attached Figure Description

[0046] Figure 1 This is an operation flowchart of the present invention;

[0047] Figure 2 This is a schematic diagram of the original polygon of the square-covered map;

[0048] Figure 3 yes Figure 2 Enlarged view of the section and schematic diagram of the cropping result;

[0049] Figure 4 yes Figure 2 A schematic diagram of the results of square grid clipping and merging;

[0050] Figure 5 This is a flowchart for calculating the backscattered energy deposition density distribution;

[0051] Figure 6 This is a schematic diagram illustrating the calculation of backscattered energy deposition density distribution;

[0052] Figure 7 This is a diagram illustrating the construction and use of CDF;

[0053] Figure 8 This is a flowchart of the calculation process for the forward scattering energy deposition density distribution;

[0054] Figure 9 This is a schematic diagram of the adjacent area;

[0055] Figure 10 This is a schematic diagram illustrating the calculation of the deposition density distribution of scattered energy; Detailed Implementation

[0056] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] This invention provides an efficient method for calculating the energy deposition density distribution of electron beam lithography (EBL) patterns in Manhattan lithography. The aim is to overcome the memory bottleneck of a single computer by employing pattern fragmentation and layered calculations, while maintaining accuracy. This significantly reduces the storage space required for EBL proximity correction and expands the processable pattern size. The steps of this invention are as follows: Figure 1As shown, the process consists of five steps: reading the Manhattan exposure pattern; splitting the Manhattan pattern into rectangles; calculating the electron beam lithography energy deposition density distribution layer by layer; determining the average error of development and measurement; and updating the rectangular exposure dose. The technical solution of this invention is as follows: Based on pattern splitting and layered calculation, the original pattern is divided into non-intersecting rectangles, each assigned an exposure dose. While ensuring preset accuracy, the contributions of forward scattering and backscattering in the proximity effect of electron beam lithography to the final energy deposition value are calculated layer by layer. The rectangular exposure dose is then adjusted based on the simulated energy deposition results, ultimately completing the proximity effect correction of the pattern. The specific implementation steps are as follows:

[0058] Step S1: Import Manhattan exposure map;

[0059] Read in the electron beam lithography Manhattan pattern and save it as multiple polygons.

[0060] Step S2: Split the Manhattan map into a rectangle;

[0061] Cover a single polygon with a square grid of side length w nm, such as Figure 2 As shown. The square grid intersecting the polygon edges is clipped into a rectangle. Figure 3 (a) is Figure 2 A magnified view of the dashed box in the image. Figure 3 (b) is Figure 3 (a) The resulting rectangular mesh after clipping remains unchanged in subsequent processing. Merging the square meshes with a side length of w nm in the middle of the polygon creates a new square mesh with a side length of 2w nm. This merging process continues until the side length of all surrounding meshes is no greater than half that of the new mesh, at which point merging stops. The final result of polygon fragmentation is as follows: Figure 4 As shown.

[0062] Step S3: Calculate the energy deposition density distribution of electron beam lithography layer by layer;

[0063] The point spread function (PSF) of electron beam lithography can be fitted by a double Gaussian function, expressed as:

[0064]

[0065]

[0066] In the formula, the physical parameter α is the forward scattering range, β is the backscattering range, η is the ratio of forward scattering to backscattering energy, K is a constant, x in formula (1) is the distance from the exposure point, and x in formula (2) is the distance from the exposure point. 2 +y 2 It is the square of the distance from the exposure point in two dimensions.

[0067] The total exposure energy deposition E(x0,y0) at the exposure point (x0,y0) is expressed as:

[0068] E(x0,y0)=∫∫PSF(x-x0,y-y0)σ(x,y)dxdy (3)

[0069] In the formula, let the dose distribution of the pattern be σ(x,y), and the integration region be the entire exposure pattern.

[0070] Since the PSF is a sum of Gaussian functions, a physical fact is that the forward scattering parameter α in the PSF is typically on the order of 10 nm, while the backscattering parameter β is typically between 1 μm and 50 μm. The ranges of forward and backscattering differ significantly, and the corresponding calculation requirements also differ. Therefore, the contributions of forward and backscattering to the total exposure energy deposition E(x0,y0) can be calculated in layers.

[0071] S3.1 Backscattered energy deposition calculation, the backscattered energy deposition calculation process is as follows: Figure 5 As shown in the diagram. First, the layout is divided into multiple square sub-layout regions based on the backscattering parameter β in the PSF. Then, the layout density D within each sub-layout is calculated. Next, the convolution of the layout density D of the sub-layout with the PSF is calculated to obtain the contribution of electron backscattering to the energy deposition at the center of each sub-layout. Finally, for any non-center location of the sub-layout, i.e., any location on the layout, the contribution of electron backscattering to its energy deposition can be obtained through interpolation. A schematic diagram of the backscattering energy deposition calculation is shown below. Figure 6 As shown.

[0072] S3.2 Forward scattering energy deposition calculation: When we only consider forward scattering, point (i,j) is the location where energy deposition needs to be calculated. Points (x1,y1) and (x2,y2) are the lower left and upper right vertices of the rectangle, respectively, and σ is the exposure dose of this rectangle. The contribution of the rectangular exposure to the forward scattering energy deposition at point (i,j) is calculated as shown in Equation (4).

[0073]

[0074] For (4) substitution, let:

[0075]

[0076] After substitution and simplification, and using the standard normal cumulative function, we get:

[0077]

[0078] Where Φ(·) is the cumulative distribution function of the standard normal distribution.

[0079] The Cumulative Distribution Function (CDF) is the contribution of an exposure rectangle with an exposure dose of (0,0) as its lower left vertex and (x,y) as its upper right vertex to the forward scattering energy deposition density distribution at the origin (0,0). Figure 7 As shown in (a), it is easy to obtain from equation (6) that...

[0080]

[0081] like Figure 7 As shown in (b), the contribution v of any exposure rectangle A with unit exposure doses at the lower left and upper right vertices of the rectangle (x1,y1) and (x2,y2) respectively, to the forward scattering energy deposition density distribution at the origin (0,0) is given by:

[0082] v=CDF(x2,y2)-CDF(x1,y2)-CDF(x2,y2)+CDF(x2,y2) (8)

[0083] Since equations (7) and (8) have linear translation invariance, for any rectangle and any location of the energy deposition density to be determined, equation (8) can be obtained through coordinate linear transformation. Thus, a CDF table can be obtained first for quick reference during calculation.

[0084] The flowchart of the forward scattering energy deposition calculation is as follows: Figure 8 As shown. First, the rectangle obtained after polygon fragmentation constructs an R-tree to facilitate searching for all pattern exposure shapes within the neighborhood when calculating the forward scattering energy deposition at any point. Then, the location where the energy deposition is to be calculated is selected; this location becomes the evaluation point. Third, the R-tree queries all pattern exposure shapes within the neighborhood of the evaluation point (a rectangular area with a side length of 6α centered on the evaluation point), such as... Figure 9 As shown, the shaded area is a square grid, and its adjacent areas are square areas as indicated by dashed lines. Finally, according to equation (8), as... Figure 10 As shown, the value of the forward scattering of the map exposure shape in the vicinity at the evaluation point is obtained by several additions and subtractions.

[0085] Step S4: Error between development and measurement mean;

[0086] After the layout energy deposition calculation is completed, the actual exposed layout shape can be obtained through development. The threshold development model used in this invention is expressed as follows:

[0087]

[0088] In the formula, E thr H(x,y) is the development threshold related to substrate solubility, and H(x,y) is the pattern shape after development.

[0089] The quality of the developed pattern can be measured by the mean-square error (MSE) of the target exposed shape of the pattern, expressed as:

[0090]

[0091] In the formula, N is the number of exposure points of the layout, and L(x,y) is the target exposure shape of the layout.

[0092] Step S5: Update the rectangular exposure dose.

[0093] When the MSE in step S4 is less than the preset error limit ∈, PEC is completed, and the algorithm proposed in this invention ends. Otherwise, the dose is updated, and steps S3 to S5 are iterated until the MSE meets the requirements. The dose update is expressed as:

[0094]

[0095] In the formula, σ k D is the exposure dose of the exposure rectangle in the k-th iteration, E is the energy deposition density at the center of the exposure rectangle, and D is the energy density at the center of the exposure rectangle. T It is the preset target energy deposition value for the map.

[0096] As shown in Table 1, the efficient method for calculating the energy deposition density distribution of electron beam lithography (EPC) in Manhattan pattern according to the present invention, for two test cases, shows the number of shapes generated when using a full-pattern pixelation method with 1nm×1nm grid pixelation and when using rectangular fused polygons, which is also the amount of data in EPC. Table 1 demonstrates that the present invention can reduce the amount of data by approximately 100 times compared to the full-pattern pixelation PEC method.

[0097] As shown in Table 2, the efficient method for calculating the energy deposition density distribution of electron beam lithography for Manhattan layouts according to the present invention, when the PSF parameters represented by equation (1) are α = 9.8 nm, β = 1826.9 nm, η = 0.326, and K = 1.0, shows the maximum absolute and relative errors of the calculated energy deposition density distribution of the test layout using the method of the present invention at different sub-layout sizes compared with the theoretical values. Table 2 demonstrates that the present invention can be used for EBLPEC energy deposition calculations while ensuring the preset accuracy.

[0098] Table 1

[0099] Full-map pixelation (1nm×1nm) 60,000 4,000,000 Rectangular Fractal Polygon 753 40,783

[0100] Table 2

[0101] 1nm <![CDATA[1.67×10 -5 ]]> <![CDATA[2.18×10 -5 ]]> 304nm <![CDATA[1.58×10 -4 ]]> <![CDATA[2.07×10 -4 ]]> 228nm <![CDATA[1.10×10 -4 ]]> <![CDATA[1.44×10 -4 ]]> 182nm <![CDATA[8.36×10 -5 ]]> <![CDATA[1.10×10 -4 ]]> 152nm <![CDATA[5.37×10 -5 ]]> <![CDATA[7.02×10 -5 ]]>

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Referring to the description of these embodiments, those skilled in the art should be able to understand and make relevant modifications or substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention.

Claims

1. An efficient method for calculating the energy deposition density distribution of electron beam lithography in Manhattan layouts, characterized in that... Includes the following steps: Step S1: Import the Manhattan exposure map; Step S2: The Manhattan map is split into a rectangle; Step S3: Calculate the energy deposition density distribution of electron beam lithography layer by layer; the point spread function (PSF) of electron beam lithography can be fitted by a double Gaussian function, expressed as: In the formula, the physical parameter α is the forward scattering range, β is the backscattering range, η is the ratio of forward scattering to backscattering energy, K is a constant, x in formula (1) is the distance from the exposure point, and x²+y² in formula (2) is the square of the distance from the exposure point in two dimensions. The total exposure energy deposition E(x0,y0) at the exposure point (x0,y0) is expressed as: In the formula, let the dose distribution of the pattern be σ(x,y), and the integration region be the entire exposure pattern; Since PSF is in the form of a Gaussian function sum, the forward scattering parameter α is generally on the order of 10 nm, and the backscattering parameter β is generally on the order of 1 μm to 50 μm. The ranges of forward and backscattering are very different, and the corresponding calculation requirements are also different. The contribution of forward scattering and backscattering to the total exposure energy deposition E(x0,y0) is obtained by layered calculation. S3.1 Backscattered energy deposition calculation: First, the layout is divided into multiple square sub-layout regions according to the backscattering parameter β in the PSF; then, the layout density D in each sub-layout is calculated; next, the convolution of the layout density D of the sub-layout with the PSF is calculated to obtain the contribution of electron backscattering to the energy deposition at the center of each sub-layout; finally, for any non-center position of the sub-layout, i.e., any position of the layout, the contribution of electron backscattering to its energy deposition is obtained by interpolation. S3.2 Forward scattering energy deposition calculation: When we only consider forward scattering, point (i,j) is the location where energy deposition needs to be calculated. Points (x1,y1) and (x2,y2) are the lower left and upper right vertices of the rectangle, respectively. σ is the exposure dose of this rectangle. The contribution of the rectangle exposure to the forward scattering energy deposition of point (i,j) is calculated as shown in Equation (4). For (4) substitution, let: After substitution and simplification, and using the standard normal cumulative function, we get: Where Φ(·) is the cumulative distribution function of the standard normal distribution; The cumulative distribution function (CDF) is the contribution of an exposure rectangle with an exposure dose of (0,0) as the lower left vertex and (x,y) as the upper right vertex to the forward scattering energy deposition density distribution at the origin (0,0). It can be easily obtained from equation (6). Let v be the contribution of any exposure rectangle A, with unit exposure doses at the lower left and upper right vertices of the rectangle (x1,y1) and (x2,y2) respectively, to the forward scattering energy deposition density distribution at the origin (0,0). Since equations (7) and (8) have linear translation invariance, any rectangle and any location of the energy deposition density to be determined can be obtained by coordinate linear transformation using equation (8). Therefore, a CDF table is first obtained for quick reference during calculation. First, the rectangle obtained after polygon splitting is used to construct an R-tree so that when calculating the forward scattering energy deposition at any point, all the pattern exposure shapes in its neighboring area can be searched. Then, the location where the energy deposition is to be calculated is selected, and this location becomes the evaluation point. Third, query all the pattern exposure shapes in the vicinity of the evaluation point through R-tree; finally, according to Equation (8), obtain the value of the forward scattering of the pattern exposure shape in the vicinity at the evaluation point through several additions and subtractions; step S4, development and measurement mean error; step S5, update the rectangular exposure dose.

2. The efficient method for calculating the energy deposition density distribution of electron beam lithography for Manhattan layouts as described in claim 1, characterized in that: In step S1, the Manhattan exposure pattern is read in; the electron beam lithography Manhattan pattern is read in and saved as multiple polygons.

3. The efficient method for calculating the energy deposition density distribution of electron beam lithography for Manhattan layouts as described in claim 1, characterized in that: In step S2, a single polygon is covered with a square mesh with a side length of w nm; the square meshes intersecting the edges of the polygons are clipped into rectangles and not changed in subsequent processing; the square meshes with a side length of wnm in the middle of the polygons are merged into a new square mesh with a side length of 2w nm, and the newly generated square meshes are continuously merged until the side length of all the meshes around the newly merged mesh is no greater than half of the new mesh, at which point the merging stops.

4. The efficient method for calculating the energy deposition density distribution of electron beam lithography for Manhattan layouts as described in claim 1, characterized in that: In step S4, the error between the development and measurement mean values; After the layout energy deposition calculation is completed, the actual exposed layout shape is obtained through development. The threshold development model used in this invention is expressed as follows: In the formula, E thr It is the development threshold related to substrate solubility, and H(x,y) is the pattern shape after development; The quality of the developed pattern is measured by the mean-square error (MSE) relative to the target exposed shape of the pattern, expressed as: In the formula, N is the number of exposure points of the layout, and L(x,y) is the target exposure shape of the layout.

5. The efficient method for calculating the energy deposition density distribution of electron beam lithography for Manhattan layouts as described in claim 1, characterized in that: In step S5, the rectangular exposure dose is updated; when the MSE in step S4 is less than the preset error limit ε, PEC is completed, and the algorithm proposed in this invention ends; otherwise, the dose is updated, and steps S3 to S5 are iterated until the MSE meets the requirements; the dose update is expressed as: In the formula, σ k D is the exposure dose of the exposure rectangle in the k-th iteration, E is the energy deposition density at the center of the exposure rectangle, and D is the energy density at the center of the exposure rectangle. T It is the preset target energy deposition value for the map.

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