Method for obtaining high-resolution graph by using different illumination modes

Abstract

The invention provides a method for obtaining a high-resolution pattern by using different illumination modes, and relates to the technical field of photoetching, and the method comprises the following steps: forming a negative photosensitive film layer, a positive photosensitive film layer and a metal enhancement layer which are stacked in sequence on a substrate; the positive photosensitive film layer is exposed by adopting a first illumination mode based on the mask plate, the negative photosensitive film layer is exposed by adopting a second illumination mode based on the mask plate, the illumination wavelength of the first illumination mode is the same as that of the second illumination mode, and the first focal depth of the first illumination mode is different from the second focal depth of the second illumination mode; sequentially developing the exposed positive light-sensitive film layer and the exposed negative light-sensitive film layer to obtain a graphic structure generated by two times of exposure; and transferring a pattern structure generated by two times of exposure to a substrate to obtain a high-resolution pattern.

Description

Technical Field

[0001] The present disclosure relates to the field of photolithography technology, and in particular to a method for obtaining high-resolution graphics by utilizing different illumination modes. Background Art

[0002] As one of the key layers of microelectronic devices, the characteristic size of the gate pattern directly represents the processing node of nanolithography technology. Among them, the preparation of high-resolution gates has gradually become a research hotspot in the field of semiconductor devices. When the gate feature size is less than 50 nm, various resolution enhancement technologies come into being. Among them, double exposure technology has been widely used in the processing of key layers of semiconductor devices. Double exposure technology splits the same key layer pattern on two masks and uses precision alignment to perform two exposures, thereby realizing the processing of gate key layer patterns with smaller feature sizes. However, as the feature size is further reduced, double exposure has higher and higher requirements for alignment accuracy, which poses a greater challenge to precision alignment technology. Summary of the invention

[0003] In view of this, an embodiment of the present disclosure provides a method for obtaining high-resolution graphics using different illumination modes, including: forming at least a negative photosensitive film layer, a positive photosensitive film layer and a metal reinforcement layer stacked in sequence on a substrate, wherein the negative photosensitive film layer is close to the substrate; using a first illumination mode to expose the positive photosensitive film layer based on a mask, and using a second illumination mode to expose the negative photosensitive film layer based on a mask, the illumination wavelengths of the first illumination mode and the second illumination mode are the same, and the first focal depth of the first illumination mode is different from the second focal depth of the second illumination mode; developing the exposed positive photosensitive film layer and the exposed negative photosensitive film layer to obtain a graphic structure generated by the two exposures; transferring the graphic structure generated by the two exposures to the substrate to obtain a high-resolution graphic.

[0004] According to an embodiment of the present disclosure, the first illumination mode includes normal incident illumination, the second illumination mode includes off-axis illumination, the illumination wavelengths of the first illumination mode and the second illumination mode include one of 365 nm, 248 nm, 193 nm, and 13.5 nm; the first focal depth is less than the second focal depth.

[0005] According to the embodiments of the present disclosure, a negative photosensitive film layer and a positive photosensitive film layer are prepared by coating, spraying, or fumigation methods; the material of the positive photosensitive film layer includes at least one of AR series photoresists, XT series photoresists, and PHS photoresists; the thickness of the positive photosensitive film layer is 20 nm to 50 nm; the material of the negative photosensitive film layer includes at least one of PMMA photoresists, SU-8 photoresists, and polyester photoresists, and the thickness of the negative photosensitive film layer is 50 nm to 1000 nm.

[0006] According to an embodiment of the present disclosure, the metal reinforcement layer is prepared by thermal evaporation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition or coating, and the material of the metal reinforcement layer includes an excited surface plasma material.

[0007] According to an embodiment of the present disclosure, the material of the light blocking layer of the mask includes at least one of chromium, silicon, and molybdenum, the mask pattern height of the mask is 30 nm to 50 nm, the period of the mask pattern is 40 nm to 300 nm, the duty cycle of the mask pattern is 3:1 to 1:1, and the critical dimension of the mask pattern is 20 nm to 150 nm.

[0008] According to an embodiment of the present disclosure, the exposure dose of normal incident illumination is 20 mJ / cm 2 -200 mJ / cm 2 , the slit width of the graphic structure on the positive photosensitive film layer is greater than half of the period of the mask graphic.

[0009] According to the embodiment of the present disclosure, the off-axis illumination has an illumination angle of 5° to 90° and an exposure dose of 50 mJ / cm 2 -300 mJ / cm 2 The line width of the graphic structure on the negative photosensitive film layer is less than half of the period of the mask graphic, and the graphic structure on the negative photosensitive film layer is opposite to the structure of the mask graphic of the mask.

[0010] According to an embodiment of the present disclosure, the exposed positive photosensitive film layer and the exposed negative photosensitive film layer are developed, including: using a positive developer to develop the positive photosensitive film layer, the positive developer includes at least one of AR300-35 developer, TMAH developer, and NAOH developer; using a negative developer to develop the negative photosensitive film layer, the negative developer includes at least one of n-butyl acetate developer, 3-ethoxyethyl propionate developer, and 2-heptanone developer.

[0011] According to an embodiment of the present disclosure, transferring the graphic structure generated by the double exposure to the substrate includes: transferring the graphic structure generated by the double exposure to the substrate by ion beam etching, reactive ion etching or inductively coupled plasma etching.

[0012] According to an embodiment of the present disclosure, the substrate includes a transparent substrate or an opaque substrate; the transparent substrate includes a quartz substrate, a glass substrate or a sapphire substrate; and the opaque substrate includes a silicon substrate.

[0013] The method for obtaining high-resolution graphics by using different illumination modes provided by the embodiments of the present disclosure has at least the following technical effects:

[0014] This method uses the characteristics of different focal depths in different illumination modes. It can realize the processing of high-tech node gate graphic structures by using only the same mask and without relying on precision alignment technology. It can obtain nano-graphic structures with doubled resolution, effectively solving the current situation that double exposure technology is heavily dependent on precision alignment technology in high-resolution graphic processing. At the same time, it reduces the number of processing masks, reduces the difficulty and cost of processing, and has high processing efficiency. This method can be applied not only to various new nano devices, but also to the processing of key layers of semiconductor chips at high-tech nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0016] Figure 1 The flowchart of the method for obtaining high-resolution graphics by using different lighting modes according to an embodiment of the present disclosure is schematically shown.

[0017] Figure 2 The structure diagram corresponding to each step in the method for obtaining high-resolution graphics using different illumination modes according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present disclosure.

[0019] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0020] Similarly, in order to simplify the present disclosure and help understand one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. The description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of the present disclosure, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0022] In view of the problem that the existing double exposure technology for processing high-tech node graphic structures is limited by the precision alignment technology, the embodiments of the present disclosure are intended to provide a method for obtaining high-resolution graphics using different illumination modes.

[0023] like Figure 1 As shown, the method of obtaining high-resolution graphics by using different lighting modes in this embodiment may include operations S110 to S140.

[0024] In operation S110, at least a negative photosensitive film layer, a positive photosensitive film layer, and a metal reinforcement layer stacked in sequence are formed on a substrate.

[0025] In operation S120, the positive photosensitive film layer is exposed based on the mask using the first illumination mode, and the negative photosensitive film layer is exposed based on the mask using the second illumination mode.

[0026] In operation S130, the exposed positive photosensitive film layer and the exposed negative photosensitive film layer are developed to obtain a pattern structure generated by double exposure.

[0027] In operation S140, the pattern structure generated by the double exposure is transferred to the substrate.

[0028] In the embodiment of the present disclosure, the negative photosensitive film layer is close to the substrate. The illumination wavelength of the first illumination mode is the same as that of the second illumination mode, and the first focal depth of the first illumination mode is different from the second focal depth of the second illumination mode. The method utilizes the characteristics that the first illumination mode and the second illumination mode have different focal depths. Based on the same illumination wavelength, only the same mask is needed and no precision alignment technology is required to realize high-tech node gate pattern structure processing.

[0029] In the embodiments of the present disclosure, a metal enhancement layer is prepared on the second photosensitive layer, which can enhance the exposure effect and improve the exposure quality.

[0030] In some embodiments, the first illumination mode includes normal incident illumination, the second illumination mode includes off-axis illumination, and the illumination wavelengths of the first illumination mode and the second illumination mode include one of 365 nm, 248 nm, 193 nm, and 13.5 nm. The first focal depth is less than the second focal depth. The exposed area of ​​the positive photosensitive film layer is removed after development, and the non-exposed area is retained. The exposed area of ​​the negative photosensitive film layer is retained after development, and the non-exposed area is removed.

[0031] This method uses the characteristic of shallow focal depth of normal incident illumination, which can only make the surface photosensitive film layer sensitive, while the bottom photosensitive layer cannot reach the focal depth and be sensitive, and selects a suitable nano-mask pattern to expose the second photosensitive film layer in the above multi-layer film. Using the same mask, the normal incident illumination is replaced with off-axis illumination. The off-axis illumination has the characteristic of long focal depth, which can penetrate the surface photosensitive layer to expose the bottom photosensitive layer, thereby realizing the exposure of the first photosensitive film layer.

[0032] In some embodiments, the substrate used in operation S110 may include a transparent substrate such as a quartz substrate, a glass substrate, or a sapphire substrate, or may include an opaque substrate such as a silicon substrate.

[0033] In some embodiments, operation S110 may further include: preparing the negative photosensitive film layer and the positive photosensitive film layer by coating, spraying or fumigation.

[0034] The material of the positive photosensitive film layer may include at least one of AR series photoresist, XT series photoresist, and PHS photoresist; the thickness of the positive photosensitive film layer may be 20 nm to 50 nm.

[0035] The material of the negative photosensitive film layer may include at least one of PMMA photoresist, SU-8 photoresist, and polyester photoresist, and the thickness of the negative photosensitive film layer may be 50 nm to 1000 nm.

[0036] In some embodiments, operation S110 may further include: preparing the metal reinforcement layer by thermal evaporation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition or coating.

[0037] The material of the metal reinforcement layer includes a surface plasmon-exciting material, for example, Ag, Al, Au, or the like.

[0038] In some embodiments, the light blocking layer material of the mask in operation S120 may include at least one of chromium, silicon, and molybdenum, the mask pattern height of the mask may be 30 nm to 50 nm, the period of the mask pattern may be 40 nm to 300 nm, the duty cycle of the mask pattern may be 3:1 to 1:1, and the critical dimension (CD) of the mask pattern may be 20 nm to 150 nm. It should be noted that the duty cycle refers to the ratio of the line width to the slit width, the period is expressed as pitch, the half-period is expressed as half-pitch, the critical dimension is expressed as CD, i.e., the line width, and the period pitch minus the critical dimension CD is the slit width. When the duty cycle is 1:1, CD is equal to half-pitch, and when the duty cycle is 3:1, CD is three times the slit width. The period of the mask pattern refers to the distance between the graphic units that appear repeatedly on the mask. This distance has a certain regularity in space, so that the entire mask pattern presents a periodic structure. The critical dimension of the mask pattern refers to a special line pattern that reflects the width of the characteristic lines of the integrated circuit, which is specially designed to evaluate and control the pattern processing accuracy of the process in the integrated circuit photomask manufacturing and lithography process.

[0039] In some embodiments, the exposure dose of the normal incident illumination in operation S120 is 20 mJ / cm 2 ~200 mJ / cm 2 By controlling the exposure dose of the normal incident illumination, the slit width of the graphic structure on the positive photosensitive film layer is larger than half of the period of the mask graphic.

[0040] In some embodiments, the off-axis illumination in operation S120 has an illumination angle of 5° to 90°, and the exposure dose of the off-axis illumination may be 50 mJ / cm 2 ~300 mJ / cm 2 By controlling the exposure dose of off-axis illumination, the line width of the graphic structure on the negative photosensitive film layer is less than half of the period of the mask graphic. Since it is a negative photosensitive material, the graphic structure on the negative photosensitive film layer is opposite to the structure of the mask graphic of the mask.

[0041] In some embodiments, developing the exposed positive photosensitive film layer and the exposed negative photosensitive film layer in operation S130 may include:

[0042] The positive photosensitive film layer is developed with a positive developer to obtain a line width graphic structure with a slit width exceeding half of the mask period. The positive developer includes at least one of AR300-35 developer, TMAH developer, NAOH developer, etc.

[0043] The negative photosensitive film layer is developed with a negative developer to obtain a pattern structure opposite to the mask pattern. The negative developer includes at least one of n-butyl acetate developer, 3-ethoxyethyl propionate developer, 2-heptanone developer, etc.

[0044] In some embodiments, transferring the pattern structure generated by the double exposure to the substrate in operation S140 may include:

[0045] Ion beam etching (IBE), reactive ion etching (RIE), inductive coupled plasma etching (ICP) or other dry etching transfer methods are used to transfer the graphic structure produced by the double exposure to the substrate, thereby obtaining a graphic structure with doubled resolution on the substrate.

[0046] In order to more clearly illustrate the method for obtaining high-resolution graphics by using different lighting modes provided by the embodiment of the present disclosure, the following is combined with Figure 2 , three specific examples are given to illustrate.

[0047] Embodiment 1:

[0048] The method for obtaining high-resolution graphics by using different illumination modes provided in this embodiment may include the following steps:

[0049] Step (1): Select a silicon substrate as substrate 1, spin-coat PMMA negative photosensitive material on substrate 1 to form a negative photosensitive film layer 2 with a thickness of 50 nm and a baking temperature of 120 °C; spin-coat AR-P3170 positive photosensitive material to form a positive photosensitive film layer 3 with a thickness of 30 nm and a baking temperature of 100 °C; deposit Ag to form a metal enhancement layer 4 by thermal evaporation coating with a deposition thickness of 10 nm. The prepared structure is as follows: Figure 2 As shown in a.

[0050] Step (2) uses a mercury lamp light source with an illumination wavelength of 365 nm, the mask light-blocking layer 5 is metal Cr, the height of the mask pattern 6 is 40 nm, the period of the mask pattern 6 is 200 nm, the mask duty ratio is 3:1, the mask line size is 150 nm, and the mask is exposed in a state where it is tightly attached to the metal reinforcement layer 4, and the exposure dose is 100 mJ / cm 2, so that the positive photosensitive film layer 3 is photosensitive. The structure prepared is as follows Figure 2 As shown in b.

[0051] Step (3) Replace the off-axis illumination and perform a second off-axis illumination exposure at the same illumination wavelength. The off-axis illumination angle is about 30° and the exposure dose is 100 mJ / cm 2 , so that the negative photosensitive film layer 2 is photosensitive. The structure prepared is as follows Figure 2 As shown in c.

[0052] Step (4) Use tape to remove the surface metal reinforcement layer 4, and use 300-35 developer to develop the positive photosensitive film layer 3 of AR-P3170 to obtain a graphic structure with a slit width of 120 nm. By controlling the exposure dose, graphic structures with different slit widths can be obtained in the positive photosensitive film layer 3. The prepared structure is as follows: Figure 2 Then, the negative photosensitive film layer 2 is developed with n-butyl acetate to obtain a grating structure with a pattern size of 50 nm on the negative photosensitive film layer 2. The prepared structure is as shown in FIG. Figure 2 As shown in figure e.

[0053] Step (5) uses IBE etching to transfer the patterns in the negative photosensitive film layer 2 and the positive photosensitive film layer 3 to the substrate 1, removes the negative photosensitive film layer 2 and the positive photosensitive film layer 3, thereby realizing a wire grid pattern structure with a period of 100 nm and a line width of 50 nm on the silicon substrate 1. The prepared structure is as shown in FIG. Figure 2 As shown in figure f.

[0054] Embodiment 2:

[0055] The method for obtaining high-resolution graphics by using different illumination modes provided in this embodiment may include the following steps:

[0056] Step (1) select a quartz substrate as substrate 1, spin-coat SU-8 negative photosensitive material on substrate 1 to form a negative photosensitive film layer 2 with a thickness of 40 nm and a baking temperature of 120 °C; spin-coat AR3170 positive photosensitive material to form a positive photosensitive film layer 3 with a thickness of 25 nm and a baking temperature of 100 °C; deposit Al to form a metal enhancement layer 4 by magnetron sputtering coating with a deposition thickness of 15 nm. The prepared structure is as follows Figure 2 As shown in a.

[0057] Step (2) uses a mercury lamp light source with an illumination wavelength of 365 nm, the mask light-blocking layer 5 is metal Cr, the height of the mask pattern 6 is 30 nm, the period of the mask pattern 6 is 120 nm, the mask duty ratio is 2:1, the mask line size is 80 nm, and the mask is exposed in a state where it is tightly attached to the metal reinforcement layer 4, with an exposure dose of 120 mJ / cm 2 , so that the positive photosensitive film layer 3 is photosensitive. The structure prepared is as follows Figure 2 As shown in b.

[0058] Step (3) Replace the off-axis illumination and perform a second off-axis illumination exposure at the same illumination wavelength. The off-axis illumination angle is about 60° and the exposure dose is 200 mJ / cm 2 , so that the negative photosensitive film layer 2 is photosensitive. The structure prepared is as follows Figure 2 As shown in c.

[0059] Step (4) removes the surface metal reinforcement layer 4 using phosphoric acid, and develops the positive photosensitive film layer 3 using a 300-35 developer to obtain a graphic structure with a slit width of 80 nm. Graphic structures with different slit widths can be obtained in the positive photosensitive film layer 3 by controlling the exposure dose. The prepared structure is as follows: Figure 2 Then, the negative photosensitive film layer 2 is developed with 3-ethoxyethyl propionate to obtain a grating structure with a pattern size of 40 nm on the negative photosensitive film layer 2. The prepared structure is as shown in FIG. Figure 2 As shown in figure e.

[0060] In step (5), RIE etching is used to transfer the patterns in the negative photosensitive film layer 2 and the positive photosensitive film layer 3 to the silicon substrate 1, and the negative photosensitive film layer 2 and the positive photosensitive film layer 3 are removed, thereby realizing a wire grid pattern structure with a period of 60 nm and a line width of 30 nm on the substrate.

[0061] Embodiment 3:

[0062] The method for obtaining high-resolution graphics by using different illumination modes provided in this embodiment may include the following steps:

[0063] Step (1) Select a sapphire substrate as substrate 1, spin-coat a polyester negative photosensitive material on substrate 1 as negative photosensitive film layer 2, with a thickness of 30 nm and a baking temperature of 120 °C; spin-coat an AZ1500 positive photosensitive material as positive photosensitive film layer 3, with a thickness of 20 nm and a baking temperature of 90 °C; deposit Au to form a metal enhancement layer 4, the deposition method is electron beam coating, and the deposition thickness is 20 nm. The prepared structure is as follows Figure 2 As shown in a.

[0064] Step (2) uses a mercury lamp light source with an illumination wavelength of 193 nm, the mask light-blocking layer 5 is metal molybdenum, the height of the mask pattern 6 is 40 nm, the period of the mask pattern 6 is 88 nm, the mask duty ratio is 3:1, the mask line size is 66 nm, and the mask is exposed in a state where it is tightly attached to the metal reinforcement layer 4, and the exposure dose is 50 mJ / cm 2 The positive photosensitive film layer 3 is photosensitive. The structure prepared is as follows Figure 2 As shown in b.

[0065] Step (3) Replace the off-axis illumination and perform a second off-axis illumination exposure at the same illumination wavelength. The off-axis illumination angle is about 50° and the exposure dose is 50 mJ / cm 2 , so that the negative photosensitive film layer 2 is photosensitive. The structure prepared is as follows Figure 2 As shown in c.

[0066] Step (4) removes the surface metal reinforcement layer 4 with adhesive tape, and develops the positive photosensitive film layer 3 with TMAH developer to obtain a graphic structure with a slit width of 60 nm. The graphic structures with different slit widths can be obtained in the positive photosensitive film layer 3 by controlling the exposure dose. The prepared structure is as follows: Figure 2 Then, the negative photosensitive film layer 2 is developed using 2-heptanone to obtain a grating structure with a pattern size of 22 nm on the negative photosensitive film layer 2. The prepared structure is as shown in FIG. Figure 2 As shown in figure e.

[0067] In step (5), the patterns in the negative photosensitive film layer 2 and the positive photosensitive film layer 3 are transferred to the substrate 1 by ICP etching, and the negative photosensitive film layer 2 and the positive photosensitive film layer 3 are removed, thereby realizing a wire grid pattern structure with a period of 44 nm and a line width of 22 nm on the substrate 1.

[0068] It should be noted that the specific parameters, material types and processing methods involved in the above examples are all for the purpose of more clearly illustrating the method for obtaining high-resolution graphics using different lighting modes provided by the embodiments of the present disclosure, and are not intended to limit the present disclosure.

[0069] The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above are only preferred embodiments of the present disclosure and the technical principles used. Those skilled in the art will understand that the present disclosure is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present disclosure. Therefore, although the present disclosure is described in more detail through the above embodiments, the present disclosure is not limited to the above embodiments, and may also include more other equivalent embodiments without departing from the concept of the present disclosure, all of which belong to the protection scope of the present disclosure.

Claims

1. A method for obtaining high-resolution graphics using different illumination modes, characterized in that: include: At least a negative photosensitive film layer, a positive photosensitive film layer and a metal reinforcement layer are stacked in sequence on the substrate, wherein the negative photosensitive film layer is close to the substrate; The positive photosensitive film layer is exposed based on a mask using a first illumination mode, and the negative photosensitive film layer is exposed based on the mask using a second illumination mode, wherein the illumination wavelength of the first illumination mode is the same as that of the second illumination mode, and the first focal depth of the first illumination mode is different from the second focal depth of the second illumination mode; The exposed positive photosensitive film layer and the exposed negative photosensitive film layer are sequentially developed to obtain a graphic structure generated by double exposure; The graphic structure generated by the double exposure is transferred to the substrate to obtain a high-resolution graphic.

2. The method according to claim 1, characterized in that The first illumination mode includes normal incident illumination, the second illumination mode includes off-axis illumination, the illumination wavelengths of the first illumination mode and the second illumination mode include one of 365 nm, 248 nm, 193 nm, and 13.5 nm; the first focal depth is less than the second focal depth.

3. The method according to claim 2, characterized in that The negative photosensitive film layer and the positive photosensitive film layer are prepared by coating, spraying, or fumigation; The material of the positive photosensitive film layer includes at least one of AR series photoresist, AZ series photoresist, and PHS photoresist; the thickness of the positive photosensitive film layer is 20 nm to 50 nm; The material of the negative photosensitive film layer includes at least one of PMMA photoresist, SU-8 photoresist and polyester photoresist, and the thickness of the negative photosensitive film layer is 50 nm to 1000 nm.

4. The method according to claim 1 or 2, characterized in that: The metal reinforcement layer is prepared by thermal evaporation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition or coating, and the material of the metal reinforcement layer includes an excited surface plasma material.

5. The method according to claim 2, characterized in that: The light-blocking layer material of the mask plate includes at least one of chromium, silicon, and molybdenum. The mask pattern height of the mask plate is 30 nm to 50 nm, the period of the mask pattern is 40 nm to 300 nm, the duty ratio of the mask pattern is 3:1 to 1:1, and the critical dimension of the mask pattern is 20 nm to 150 nm.

6. The method according to claim 5, characterized in that The exposure dose of the normal incident illumination is 20 mJ / cm 2 -200 mJ / cm 2 The slit width of the graphic structure on the positive photosensitive film layer is greater than half of the period of the mask graphic.

7. The method according to claim 5, characterized in that The off-axis illumination has an illumination angle of 5° to 90° and an exposure dose of 50 mJ / cm 2 -300 mJ / cm 2 The line width of the graphic structure on the negative photosensitive film layer is less than half of the period of the mask graphic, and the graphic structure on the negative photosensitive film layer is opposite to the structure of the mask graphic of the mask.

8. The method according to claim 2, characterized in that: The step of sequentially developing the exposed positive photosensitive film layer and the exposed negative photosensitive film layer comprises: The positive photosensitive film layer is developed using a positive developer, wherein the positive developer comprises at least one of an AR300-35 developer, a TMAH developer, and a NAOH developer; The negative photosensitive film layer is developed by using a negative developer, wherein the negative developer comprises at least one of a n-butyl acetate developer, a 3-ethoxyethyl propionate developer, and a 2-heptanone developer.

9. The method according to claim 1 or 2, characterized in that: The step of transferring the graphic structure generated by the double exposure to the substrate comprises: The graphic structure generated by the double exposure is transferred to the substrate by ion beam etching, reactive ion etching or inductively coupled plasma etching.

10. The method according to claim 1 or 2, characterized in that: The substrate includes a transparent substrate or an opaque substrate; The transparent substrate includes a quartz substrate, a glass substrate or a sapphire substrate; The opaque substrate includes a silicon substrate.

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