High numerical aperture illumination photoetching mask for super-resolution photoetching and preparation method and photoetching method thereof

Abstract

The invention provides a high-numerical-aperture illumination photoetching mask for super-resolution photoetching, a preparation method thereof and a photoetching method. The high-numerical-aperture illumination photoetching mask comprises a photoetching mask substrate; the photoetching mask pattern structure is arranged on the first surface of the photoetching mask substrate; the high numerical aperture illumination structure is formed on the second surface of the photoetching mask substrate, and the second surface is opposite to the first surface; the high numerical aperture illumination structure comprises a zigzag grating structure formed by alternately connecting a plurality of first side wall parts and a plurality of second side wall parts, a reflecting film layer is formed on the surface of each first side wall part, and the included angle between each first side wall part and the second surface is smaller than that between each second side wall part and the second surface.

Description

Technical Field

[0001] The present disclosure relates to the field of photolithography technology, and in particular to a high numerical aperture illumination photolithography mask for super-resolution photolithography, a preparation method thereof, and a photolithography method. Background Art

[0002] High numerical aperture illumination is one of the most effective ways to improve lithography resolution and imaging contrast. Currently, many methods for achieving high numerical aperture illumination have been proposed, among which prism reflection method and grating spectrometry are two common high numerical aperture illumination methods. The prism reflection principle is relatively simple and low cost, and can obtain high numerical aperture illumination with a refractive index slightly lower than that of the prism material. However, the prism reflection method has certain requirements on the transmittance of the prism material, mask substrate material, etc. Too low transmittance will greatly reduce the lighting effect. The grating spectrometry method can stimulate higher numerical aperture illumination light, but the intensity of the 0th order light is often higher than the intensity of the diffracted light, which seriously affects the effect of improving the imaging contrast. Summary of the invention

[0003] In view of this, the embodiments of the present disclosure provide a high numerical aperture illumination lithography mask for super-resolution lithography and a preparation method thereof, and a lithography method.

[0004] A first aspect of an embodiment of the present disclosure provides a high numerical aperture illumination lithography mask for super-resolution lithography, comprising: a lithography mask substrate; a lithography mask graphic structure, arranged on a first surface of the lithography mask substrate; a high numerical aperture illumination structure, formed on a second surface of the lithography mask substrate, the second surface being opposite to the first surface; the high numerical aperture illumination structure comprising a sawtooth grating structure consisting of a plurality of first side wall portions and a plurality of second side wall portions alternately connected, a reflective film layer being formed on a surface of the first side wall portion, and an angle between the first side wall portion and the second surface being smaller than an angle between the second side wall portion and the second surface.

[0005] According to an embodiment of the present disclosure, the angles between different first side wall portions and the second surface are the same or different, and the angles between different second side wall portions and the second surface are the same or different.

[0006] According to an embodiment of the present disclosure, the angle between the first side wall portion and the second surface is 45° to 75°, and the angle between the second side wall portion and the second surface is 80° to 90°.

[0007] According to an embodiment of the present disclosure, a period of the sawtooth grating structure along a direction parallel to the second surface is 500 nm to 1 mm.

[0008] According to an embodiment of the present disclosure, the material of the photolithography mask substrate includes a quartz substrate, a glass substrate or a sapphire substrate, and the thickness of the photolithography mask substrate is 0.01 mm to 100 mm. The material of the photolithography mask pattern structure includes at least one of chromium, molybdenum, nickel, germanium, and silicon, and the thickness of the photolithography mask pattern structure is 10 nm to 150 nm.

[0009] According to an embodiment of the present disclosure, the reflective film layer is a single-layer reflective film or a multi-layer reflective film, and the material of the reflective film layer includes at least one of chromium, aluminum, molybdenum, and tungsten.

[0010] A second aspect of an embodiment of the present disclosure provides a method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography, comprising: preparing a lithography mask graphic structure on a first surface of a lithography mask substrate; preparing a sawtooth grating structure on a second surface of the lithography mask substrate, the second surface being opposite to the first surface; the sawtooth grating structure being composed of a plurality of first side wall portions and a plurality of second side wall portions alternately connected, the angle between the first side wall portion and the second surface being smaller than the angle between the second side wall portion and the second surface; preparing a reflective film layer on the surface of the first side wall portion, the reflective film layer and the sawtooth grating structure together constituting a high numerical aperture illumination structure.

[0011] According to an embodiment of the present disclosure, a photolithography mask pattern structure is prepared on a first surface of a photolithography mask substrate, including: preparing the photolithography mask pattern structure by electron beam direct writing lithography, laser direct writing lithography, focused ion beam direct writing, surface plasma lithography, projection lithography, ion beam etching, reactive ion etching, inductively coupled plasma etching or wet etching;

[0012] The sawtooth grating structure is formed on the second surface of the photolithography mask substrate, comprising: preparing the sawtooth grating structure by photolithography, laser direct writing, electron beam direct writing, reactive ion etching, inductively coupled plasma etching, wet etching or diamond lathe turning;

[0013] The reflective film layer is prepared on the surface of the first side wall portion, including: preparing the reflective film layer by evaporation, sputtering or pulsed laser deposition.

[0014] A third aspect of the embodiments of the present disclosure provides a photolithography method, comprising: placing a high numerical aperture illumination photolithography mask above an exposure position of a substrate coated with at least photoresist, and controlling a gap between the high numerical aperture illumination photolithography mask and a surface of the substrate coated with at least photoresist; the high numerical aperture illumination photolithography mask adopts the high numerical aperture illumination photolithography mask described above or the high numerical aperture illumination photolithography mask prepared by the preparation method described above;

[0015] Using an illumination light source to vertically illuminate the upper surface of a high numerical aperture illumination photolithography mask, converting the vertical illumination light into high numerical aperture illumination light through a high numerical aperture illumination structure, and using the high numerical aperture illumination light to illuminate the photolithography mask pattern structure to expose the photoresist;

[0016] The exposed photoresist is developed to obtain a super-resolution graphic structure.

[0017] According to an embodiment of the present disclosure, the wavelength range of the illumination light source is 157 nm~450 nm; the gap between the high numerical aperture illumination lithography mask and the substrate surface coated with at least photoresist is 0 nm~120 nm, and the gap is filled with air, water or high refractive index liquid.

[0018] The high numerical aperture illumination lithography mask for super-resolution lithography and the preparation method thereof, and the lithography method provided in the embodiments of the present disclosure have at least the following technical effects:

[0019] The high numerical aperture illumination lithography mask utilizes a sawtooth structure and a reflective film layer to form a high numerical aperture illumination structure, which is integrated on the back of the lithography mask pattern structure, forming a simple, low-cost high numerical aperture lithography mask that can avoid the shortcomings of traditional prism reflection or grating splitting off-axis high numerical aperture illumination, thereby improving imaging contrast and lithography pattern quality.

[0020] This method can be integrated with the existing mask system to achieve a lightweight and miniaturized high numerical aperture illumination mask structure, thereby further improving the current lithography resolution and contrast. This method can prepare a high numerical aperture illumination lithography mask through conventional coating, lithography, and etching transfer. The preparation is simple and low-cost, and it is expected to be applied to the processing of key layers of microelectronic devices at higher technology nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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:

[0022] Figure 1 The structure of a high numerical aperture illumination lithography mask for super-resolution lithography according to an embodiment of the present disclosure is schematically shown.

[0023] Figure 2 A flow chart of a method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography according to an embodiment of the present disclosure is schematically shown.

[0024] Figure 3A-3C The structural diagram corresponding to each operation in the preparation method according to the embodiment of the present disclosure is schematically shown.

[0025] Figure 4A flow chart of a lithography method based on a high numerical aperture illumination lithography mask according to an embodiment of the present disclosure is schematically shown.

[0026] Figure 5A-Figure 5B The structure diagram corresponding to the photolithography method according to the embodiment of the present disclosure is schematically shown.

[0027] Figure 6 The size diagram of the super-resolution graphic structure obtained according to Example 1 of the present disclosure is schematically shown.

[0028] Figure 7 The size diagram of the super-resolution graphic structure obtained according to Example 2 of the present disclosure is schematically shown.

[0029] Figure 8 The size diagram of the super-resolution graphic structure obtained according to Example 3 of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present disclosure more clear, the present disclosure is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "include", "comprising" and the like used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0031] In the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0032] Similarly, in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof.

[0033] 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.

[0034] In order to solve the problem that high numerical aperture illumination is difficult to improve graphic resolution and contrast, the embodiments of the present disclosure aim to provide a high numerical aperture illumination lithography mask for super-resolution lithography, a preparation method thereof, and a lithography method.

[0035] Figure 1 The structure of a high numerical aperture illumination lithography mask for super-resolution lithography according to an embodiment of the present disclosure is schematically shown.

[0036] like Figure 1 As shown, the high numerical aperture illumination lithography mask for super-resolution lithography provided in this embodiment may include: a lithography mask pattern structure 1, a lithography mask substrate 2 and a high numerical aperture illumination structure.

[0037] The photolithography mask pattern structure 1 can be arranged on the first surface of the photolithography mask substrate 2. The high numerical aperture illumination structure can be formed on the second surface of the photolithography mask substrate 2, and the second surface is opposite to the first surface. The high numerical aperture illumination structure includes a sawtooth grating structure 3 composed of a plurality of first sidewall portions and a plurality of second sidewall portions alternately connected, a reflective film layer 4 is formed on the surface of the first sidewall portion, and the angle between the first sidewall portion and the second surface is smaller than the angle between the second sidewall portion and the second surface.

[0038] The first side wall portion may correspond to Figure 1 The slope of the middle protrusion (triangular tip), the second side wall portion may correspond to Figure 1 The steep slope of the middle protrusion (triangular tip), that is, the slope of the sawtooth structure, is provided with an illumination light reflecting film layer, and there is no reflecting film layer on the steep slope. The sawtooth structure and the reflecting film layer on the slope together constitute a high numerical aperture illumination structure.

[0039] The upper surface of the photolithography mask substrate 2 is vertically illuminated, and the illumination light irradiated on the reflective film layer 4 on the slope of the high numerical aperture illumination structure generates high numerical aperture (greater than 1) reflected light with a transmission direction inclined to the photolithography mask pattern structure 1 after reflection. The reflected light enters the photolithography mask pattern structure 1 through the steep slope of the high numerical aperture illumination structure, thus realizing high numerical aperture illumination. However, due to the angle problem, the steep slope of the high numerical aperture illumination structure cannot be penetrated or only a small part of the vertical illumination is penetrated.

[0040] Based on the above embodiments, the material of the photolithography mask pattern structure 1 may include at least one of chromium, molybdenum, nickel, germanium, and silicon, and the thickness of the photolithography mask pattern structure 1 may be 10 nm to 150 nm. The photolithography mask pattern structure 1 may be a grating, a dot matrix, a mark, or other pattern structures.

[0041] Based on the above embodiments, the material of the photolithography mask substrate 2 may include a transparent substrate such as a quartz substrate, a glass substrate or a sapphire substrate, and the thickness of the photolithography mask substrate 2 may be 0.01 mm to 100 mm.

[0042] Based on the above embodiments, the angles between different first side wall portions and the second surface in the sawtooth grating structure 3 are the same or different, and the angles between different second side wall portions and the second surface are the same or different, so as to provide the most suitable high numerical aperture illumination light for the lithography mask graphic structures with different periods.

[0043] For example, Figure 1 The inclination angle of the slope of the first triangle tip on the left side and the inclination angle of the slope of the second triangle tip on the left side can be different, and the inclination angles of the slopes of other triangle tips are the same. It can be set according to actual lithography requirements and is not limited in the present disclosure.

[0044] Furthermore, the included angle between the first side wall portion and the second surface may be 45° to 75°, and the included angle between the second side wall portion and the second surface may be 80° to 90°.

[0045] The sawtooth grating structure 3 can be a one-dimensional grating structure or a two-dimensional grating structure, that is, the sawtooth structure can be a one-dimensional array or a two-dimensional array.

[0046] Based on the above embodiment, the period of the sawtooth grating structure 3 along the direction parallel to the second surface is 500nm-1mm. Figure 1 Horizontal direction shown from left to right.

[0047] On the basis of the above embodiments, the reflective film layer is a single-layer reflective film or a multi-layer reflective film, and the material of the reflective film layer includes at least one of chromium, aluminum, molybdenum and tungsten.

[0048] The embodiments of the present disclosure also provide a method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography. Figure 2 A flow chart of a method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography according to an embodiment of the present disclosure is schematically shown. Figure 3A-3C The structural diagram corresponding to each operation in the preparation method according to the embodiment of the present disclosure is schematically shown.

[0049] like Figure 2 As shown, the preparation method of this embodiment may include operations S210 to S230.

[0050] In operation S210, a photolithography mask pattern structure is prepared on a first surface of a photolithography mask substrate.

[0051] In operation S220, a sawtooth grating structure is formed on the second surface of the photolithography mask substrate.

[0052] In operation S230, a reflective film layer is prepared on the surface of the first side wall portion, and the reflective film layer and the sawtooth grating structure together form a high numerical aperture illumination structure.

[0053] The second surface is opposite to the first surface. The sawtooth grating structure is composed of a plurality of first sidewall portions and a plurality of second sidewall portions alternately connected. The angle between the first sidewall portion and the second surface is smaller than the angle between the second sidewall portion and the second surface.

[0054] Based on the above embodiment, the step of preparing a photolithography mask pattern structure on the first surface of the photolithography mask substrate in operation S210 may include:

[0055] The photolithography mask pattern structure is prepared by electron beam direct writing lithography, laser direct writing lithography, focused ion beam direct writing, surface plasma lithography, projection lithography, ion beam etching, reactive ion etching, inductively coupled plasma etching or wet etching. The prepared structure is as follows Figure 3A shown.

[0056] Based on the above embodiment, the sawtooth grating structure on the second surface of the photolithography mask substrate in operation S220 may include:

[0057] The sawtooth grating structure is prepared by photolithography, laser direct writing, electron beam direct writing, reactive ion etching, inductively coupled plasma etching, wet etching or diamond lathe turning. The prepared structure is as follows Figure 3B shown.

[0058] Based on the above embodiment, the process of preparing a reflective film layer on the surface of the first sidewall portion in operation S230 includes:

[0059] The reflective film layer is prepared by evaporation, sputtering or pulsed laser deposition. The sawtooth grating structure is prepared by a diamond lathe. The prepared structure is as follows Figure 3C shown.

[0060] For details not included in this embodiment, please refer to the above-mentioned embodiment of the high numerical aperture illumination lithography mask for super-resolution lithography, which will not be repeated here.

[0061] The embodiment of the present disclosure also provides a photolithography method, Figure 4 A flow chart of a lithography method based on a high numerical aperture illumination lithography mask according to an embodiment of the present disclosure is schematically shown. Figure 5A-Figure 5B The structure diagram corresponding to the photolithography method according to the embodiment of the present disclosure is schematically shown.

[0062] like Figure 4As shown, the photolithography method of this embodiment may include operations S410 to S430.

[0063] In operation S410, a high numerical aperture illumination lithography mask is placed above an exposure position of a substrate coated with at least photoresist, and a gap between the high numerical aperture illumination lithography mask and the surface of the substrate coated with at least photoresist is controlled. The gap between the lithography mask and the surface of the substrate coated with at least photoresist can be controlled so that the mask pattern structure of the high numerical aperture illumination lithography mask is close to or in contact with the photoresist;

[0064] In operation S420, the illumination light source is used to perform vertical illumination on the upper surface of the high numerical aperture illumination lithography mask, the high numerical aperture illumination structure is used to convert the vertical illumination light into high numerical aperture illumination light, and the high numerical aperture illumination light is used to illuminate the lithography mask pattern structure to expose the photoresist.

[0065] Vertical illumination means that the illumination light is perpendicular to the lower surface of the photolithography mask (the second surface is not flat, so it should be perpendicular to the first surface). The main principle of the high numerical aperture illumination structure to convert vertical illumination into high numerical aperture illumination is that the vertical illumination light irradiated on the reflective film layer of the illumination structure is reflected and becomes obliquely incident illumination light, and enters the photolithography mask through the steep slope of the sawtooth structure, becoming high numerical aperture illumination. The schematic diagram of the photolithography is shown in the figure. Figure 5A shown.

[0066] In operation S430, the exposed photoresist is developed to obtain a super-resolution pattern structure.

[0067] Super-resolution graphics structure Figure 5B shown.

[0068] The high numerical aperture illumination photolithography mask in this embodiment adopts the high numerical aperture illumination photolithography mask mentioned above or the high numerical aperture illumination photolithography mask prepared by the above preparation method;

[0069] Based on the above embodiment, the wavelength range of the illumination light source may be 157 nm to 450 nm; and the gap between the high numerical aperture illumination photolithography mask and the substrate surface coated with at least the photoresist may be 0 nm to 120 nm.

[0070] The gap between the high numerical aperture illumination mask and the photoresist may also be filled with air, water or other high refractive index liquids, wherein the refractive index of the other high refractive index liquids is greater than or equal to 1.45.

[0071] In order to more clearly illustrate the high numerical aperture illumination lithography mask for super-resolution lithography and its preparation method and lithography method of the embodiments of the present disclosure, some specific embodiments are listed below for illustration.

[0072] Embodiment 1:

[0073] The steps of the method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography and the lithography method of this embodiment can be as follows:

[0074] Step (1) A chromium mask pattern structure is prepared on a 6.35 mm quartz mask substrate, the mask pattern period is 120 nm, the duty cycle is 1:1, the mask pattern height is 50 nm, and the mask processing method is focused ion beam direct writing.

[0075] Step (2) uses laser direct writing to prepare a sawtooth structure grating pattern on the upper surface of the photolithography mask, and then uses etching to realize the processing of the sawtooth pattern. The period of the processed sawtooth pattern is 2 μm, and the angle between the slope and the substrate plane is 60°.

[0076] Step (3) depositing a metal Ag reflective film layer on the slope of the sawtooth structure, with a deposition thickness of 50 nm by magnetron sputtering. The sawtooth structure and the reflective film layer form a high numerical aperture illumination structure.

[0077] Step (4) places the photolithography mask above the exposure position of the substrate coated with photoresist, and controls the gap between the photolithography mask and the surface of the substrate coated with photoresist to be 100 nm, and uses ultraviolet 365 nm illumination light to vertically illuminate the upper surface of the photolithography mask. The illumination structure converts the vertical illumination into high numerical aperture illumination, and the numerical aperture is about 1.3 (1.475×sin(60°)). The photoresist is 3170 photoresist with a thickness of 30 nm.

[0078] After exposure in step (5), the image is developed using a 300-35 developer to obtain a super-resolution graphic structure.

[0079] Figure 6 The size diagram of the super-resolution graphic structure obtained according to Example 1 of the present disclosure is schematically shown.

[0080] like Figure 6 As shown, the half-period of the obtained graphic structure is 60 nm.

[0081] Embodiment 2:

[0082] The steps of the method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography and the lithography method of this embodiment can be as follows:

[0083] Step (1) A molybdenum mask pattern structure is prepared on a sapphire mask substrate with a thickness of 1 mm, the mask pattern period is 64 nm, the duty cycle is 1:1, the mask pattern height is 40 nm, and the mask processing method is electron beam lithography combined with inductively coupled plasma etching process.

[0084] In step (2), a sawtooth structure grating pattern is prepared on the upper surface of the photolithography mask by electron beam direct writing, and then the sawtooth pattern is processed by etching. The processed sawtooth pattern has a period of 500 nm, a sawtooth depth of 100 nm, and an angle between the slope and the substrate plane of about 60°.

[0085] Step (3) deposits a metal Al reflective film layer on the slope of the sawtooth structure. The thickness of the deposited film layer is 30 nm. The deposition method is electron beam evaporation. The sawtooth structure and the reflective film layer form a high numerical aperture illumination structure.

[0086] Step (4) places the photolithography mask above the exposure position of the photolithography substrate, and controls the gap between the photolithography mask and the surface of the substrate coated with the photoresist to be 50 nm. The upper surface of the photolithography mask is vertically illuminated by ultraviolet 248 nm illumination light. The illumination structure converts the vertical illumination into high numerical aperture illumination. The numerical aperture is about 1.5 (1.79×sin(57°)). The photoresist is phenolic resin photoresist with a thickness of 40 nm.

[0087] After exposure in step (5), the super-resolution graphic structure is obtained by developing with TMAH developer.

[0088] Figure 7 The size diagram of the super-resolution graphic structure obtained according to Example 2 of the present disclosure is schematically shown.

[0089] like Figure 7 As shown, the half-period of the obtained graphic structure is 45 nm.

[0090] Embodiment 3:

[0091] The steps of the method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography and the lithography method of this embodiment can be as follows:

[0092] Step (1) A chromium mask pattern structure is prepared on a sapphire mask substrate with a thickness of 5 mm. The mask pattern period is 44 nm, the duty ratio is 1:1, the mask pattern height is 30 nm, and the mask processing method is electron beam lithography combined with inductively coupled plasma etching process.

[0093] Step (2) uses projection lithography to prepare a sawtooth structure grating pattern on the upper surface of the lithography mask, and then uses etching to realize the processing of the sawtooth pattern. The period of the processed sawtooth pattern is 1000 nm, and the angle between the slope and the substrate plane is about 57°.

[0094] Step (3) deposits a metal Al reflective film layer on the slope of the sawtooth structure. The deposited thickness is 100 nm and the deposition method is thermal evaporation coating. The sawtooth structure and the reflective film layer form a high numerical aperture illumination structure.

[0095] Step (4) placing a photolithography mask above the exposure position of the photolithography substrate, and controlling the gap between the photolithography mask and the surface of the substrate coated with the photoresist to be 20 nm, using ultraviolet 193 nm illumination light to vertically illuminate the upper surface of the photolithography mask, and the illumination structure converts the vertical illumination into high numerical aperture illumination, the numerical aperture is about 1.62 (1.79×sin(65°), and the photoresist is phenolic resin photoresist with a thickness of 20 nm;

[0096] After exposure in step (5), the super-resolution graphic structure is obtained by developing with TMAH developer.

[0097] Figure 8 The size diagram of the super-resolution graphic structure obtained according to Example 3 of the present disclosure is schematically shown.

[0098] like Figure 8 As shown, the half-period of the obtained graphic structure is 32 nm.

[0099] It should be noted that the specific parameters, material types and processes involved in the above examples are for the purpose of more clearly illustrating the high numerical aperture illumination lithography mask for super-resolution lithography and its preparation method and lithography method provided in the embodiments of the present disclosure, and are not intended to limit the present disclosure.

[0100] 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 high numerical aperture illumination lithography mask for super-resolution lithography, characterized in that: include: Photolithography mask substrate; A photolithography mask pattern structure is disposed on the first surface of the photolithography mask substrate; A high numerical aperture illumination structure is formed on the second surface of the photolithography mask substrate, the second surface is opposite to the first surface; the high numerical aperture illumination structure comprises a sawtooth grating structure composed of a plurality of first side wall portions and a plurality of second side wall portions alternately connected, a reflective film layer is formed on the surface of the first side wall portion, and an angle between the first side wall portion and the second surface is smaller than an angle between the second side wall portion and the second surface.

2. The high numerical aperture illumination lithography mask according to claim 1, characterized in that: The included angles between different first side wall portions and the second surface are the same or different, and the included angles between different second side wall portions and the second surface are the same or different.

3. The high numerical aperture illumination lithography mask according to claim 1 or 2, characterized in that: An included angle between the first side wall portion and the second surface is 45° to 75°, and an included angle between the second side wall portion and the second surface is 80° to 90°.

4. The high numerical aperture illumination lithography mask according to claim 1, characterized in that: The period of the sawtooth grating structure along a direction parallel to the second surface is 500 nm to 1 mm.

5. The high numerical aperture illumination lithography mask according to claim 1, characterized in that: The material of the photolithography mask substrate includes a quartz substrate, a glass substrate or a sapphire substrate, and the thickness of the photolithography mask substrate is 0.01 mm to 100 mm; The material of the photolithography mask pattern structure includes at least one of chromium, molybdenum, nickel, germanium, and silicon, and the thickness of the photolithography mask pattern structure is 10 nm to 150 nm.

6. The high numerical aperture illumination lithography mask according to claim 1, characterized in that: The reflective film layer is a single-layer reflective film or a multi-layer reflective film, and the material of the reflective film layer includes at least one of chromium, aluminum, molybdenum, and tungsten.

7. A method for preparing a high numerical aperture illumination lithography mask for super-resolution lithography, characterized in that: include: Preparing a photolithography mask pattern structure on a first surface of a photolithography mask substrate; A sawtooth grating structure is prepared on the second surface of the photolithography mask substrate, the second surface is opposite to the first surface; the sawtooth grating structure is composed of a plurality of first sidewall portions and a plurality of second sidewall portions connected alternately, and an angle between the first sidewall portion and the second surface is smaller than an angle between the second sidewall portion and the second surface; A reflective film layer is prepared on the surface of the first side wall portion, and the reflective film layer and the sawtooth grating structure together constitute a high numerical aperture illumination structure.

8. The preparation method according to claim 7, characterized in that: The step of preparing a photolithography mask pattern structure on the first surface of the photolithography mask substrate comprises: The photolithography mask pattern structure is prepared by electron beam direct writing lithography, laser direct writing lithography, focused ion beam direct writing, surface plasma lithography, projection lithography, ion beam etching, reactive ion etching, inductively coupled plasma etching or wet etching; The sawtooth grating structure on the second surface of the photolithography mask substrate comprises: The sawtooth grating structure is prepared by photolithography, laser direct writing, electron beam direct writing, reactive ion etching, inductively coupled plasma etching, wet etching or diamond lathe turning; The step of preparing a reflective film layer on the surface of the first sidewall portion comprises: The reflective film layer is prepared by evaporation, sputtering or pulsed laser deposition.

9. A photolithography method, characterized in that: include: Placing a high numerical aperture illumination photolithography mask above an exposure position of a substrate coated with at least photoresist, and controlling a gap between the high numerical aperture illumination photolithography mask and the surface of the substrate coated with at least photoresist; the high numerical aperture illumination photolithography mask is the high numerical aperture illumination photolithography mask as described in any one of claims 1 to 6 or the high numerical aperture illumination photolithography mask prepared by the preparation method as described in claim 7 or 8; Using an illumination light source to perform vertical illumination on the upper surface of a high numerical aperture illumination photolithography mask, converting the vertical illumination light into high numerical aperture illumination light through the high numerical aperture illumination structure, and using the high numerical aperture illumination light to illuminate the photolithography mask pattern structure to expose the photoresist; The exposed photoresist is developed to obtain a super-resolution graphic structure.

10. The photolithography method according to claim 9, characterized in that: The wavelength range of the illumination light source is 157 nm to 450 nm; the gap between the high numerical aperture illumination photolithography mask and the substrate surface coated with at least photoresist is 0 nm to 120 nm; and the gap is filled with air, water or high refractive index liquid.

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