Adjustable imprinting master mask and preparation method thereof

Abstract

The invention provides an adjustable imprinting master mask and a preparation method thereof. The adjustable imprinting master mask comprises a first material layer, an insulating layer, a first metal layer, a second material layer and a second metal layer which are arranged in sequence, patterning the second metal layer to form a micro-nano structure in the second material layer; the micro-nano structure generates displacement along a first direction under the modulation of a first voltage applied to the first material layer; and / or; the micro-nano structure generates displacement along a second direction under the modulation of a second voltage applied to the first metal layer and the second metal layer; the first direction is a direction in which incident light is propagated in the first material layer along the micro-nano structure and is parallel to the first material layer; the second direction is a direction along the height direction of the micro-nano structure and far away from the first material layer; the width of the micro-nano structure in the first direction is increased or decreased; and / or; and the height of the micro-nano structure in the second direction is increased or decreased, so that the cycle, duty ratio and height adjustment of the micro-nano structure within a certain range is realized, and the applicability and the utilization rate of the mother set are improved.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to an adjustable imprint master and a preparation method thereof. Background Art

[0002] In an existing method for manufacturing a micro-nano structure, the first step is to prepare an imprinting master, which is then etched based on the designed micro-nano structure to form the required imprinting master, and then the imprinting glue layer is imprinted through the imprinting master to form a micro-nano micro-nano structure. Often, the structure of the imprinting master is etched according to a pre-designed design, and the micro-nano micro-nano structure of each area of ​​the master is uniquely determined. When the micro-nano micro-nano structure of different areas of the master needs to be adjusted according to different ID requirements of the design, the imprinting master needs to be remade. Therefore, the existing master design can only be designed for a micro-nano micro-nano structure of a determined ID, and has poor flexibility and cannot adapt to application scenarios when multiple micro-nano micro-nano structures change, especially when local micro-nano micro-nano structures change, which easily leads to low efficiency of the existing master and high production costs.

[0003] Therefore, the present invention is intended to solve the problems existing in the prior art and improve the prior art. Summary of the invention

[0004] The present invention provides an adjustable imprint master and a preparation method thereof, which aims to solve the problem that the structure of the imprint master in the prior art is not adjustable, adjust the micro-nano structures in different areas, and improve the adjustability of the micro-nano structures in some areas of the imprint master.

[0005] An adjustable grating master, comprising a first material layer, an insulating layer, a first metal layer, a second material layer and a second metal layer arranged in sequence; the second metal layer is patterned to form a micro-nano structure in the second material layer, and the micro-nano structure is used for embossing to form an optical structure of an optical product; the micro-nano structure is displaced along a first direction under a first voltage modulation applied to the first material layer; and / or the micro-nano structure is displaced along a second direction under a second voltage modulation applied to the first metal layer and the second metal layer; the first direction is the direction in which incident light propagates along the micro-nano structure and in the first material layer; the second direction is the direction along the height of the micro-nano structure and away from the first material layer.

[0006] Furthermore, it also includes that the width of the micro-nano structure in the first direction increases or decreases; and / or; the height of the micro-nano structure in the second direction increases or decreases.

[0007] Further, optionally, the first voltage and the second voltage are different; the displacement generated along the first direction △L1=d1*V1, wherein d1 represents the piezoelectric strain coefficient of the first material layer, and V1 is the magnitude of the applied first voltage; the displacement generated along the second direction △L2=d2*V2, wherein d2 represents the piezoelectric strain coefficient of the second material layer, and V2 is the magnitude of the applied first voltage.

[0008] Furthermore, in some other embodiments, a third direction is also included, and the length of the micro-nano structure in the third direction increases or decreases, and the third direction is parallel to the direction of the first material layer and perpendicular to the first direction.

[0009] In some embodiments, the first material layer is piezoelectric ceramic; the insulating layer is SiO2, Si3N4, etc.

[0010] In some other embodiments, the thickness of the second metal layer ≥ the thickness of the second material layer * etching selectivity ratio 1, etching selectivity ratio 1 = etching rate of the second metal layer / etching rate of the second material layer; the thickness of the photoresist layer ≥ the thickness of the second metal layer * etching selectivity ratio 2, etching selectivity ratio 2 = etching rate of the photoresist layer / etching rate of the second metal layer.

[0011] Furthermore, the optical structure is a diffractive optical structure, including a one-dimensional grating structure, and / or a two-dimensional grating structure, and / or a DOE, and / or a diffuser.

[0012] At the same time, the present invention provides a method for preparing an adjustable imprint master, which is used to prepare the adjustable imprint master as described in any of the above embodiments, and comprises the following steps:

[0013] (1) providing a first material layer, and sequentially arranging an insulating layer, a first metal layer, a second material layer, and a second metal layer on the first material layer; and depositing a photoresist layer on a surface of the second metal layer, and performing patterning on the photoresist layer;

[0014] (2) using the patterned photoresist layer as a mask layer, etching the second metal layer to form a patterned second metal layer structure; and removing the photoresist;

[0015] (3) Using the patterned second metal layer structure as a mask, etching the second material layer to obtain a micro-nano structure layer; and retaining the second metal layer structure to obtain an adjustable imprint master.

[0016] Furthermore, the method further comprises step (4), wherein electrode sheets are provided at both ends of the first material layer and electrically connected to each other, and the deformation displacement of the first material layer in the first direction and the third direction is achieved by controlling the voltage.

[0017] Furthermore, the method further comprises step (5), applying and controlling voltage at both ends of the first metal layer and the second metal layer so that the height of the micro-nano structure layer increases or decreases.

[0018] The present invention provides an adjustable imprint master and a method for making the same, so as to change the micro-nano structure of a local area of ​​the master to meet different design ID requirements, realize the adjustment of the period, duty cycle and height of the micro-nano structure within a certain range, improve the applicability and utilization rate of the master, shorten the iteration cycle of the design, and save production costs.

[0019] Furthermore, based on the adjustable imprinting master prepared in the steps of the present invention, the parameters of the micro-nano structures at different positions can be controlled respectively based on the first material layer, the first metal layer and the second metal layer and the first voltage and the second voltage at different positions, so as to realize the modulation of the period, duty cycle, width and other parameters of the micro-nano structures. According to different design IDs, different first voltages and second voltages are determined based on the required parameters, and the voltage values ​​at different positions are controlled respectively to realize the control of the positions and parameters of multiple micro-nano structures, so that the imprinting master can adapt to the application scenarios when multiple micro-nano structures change, improve the reuse rate of the imprinting master, and use the micro-nano structure to imprint and form the optical structure of the optical product in this field, so that the period, duty cycle, width, height and other parameters of the optical structure are adjustable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of the steps of a method for preparing an adjustable imprint master provided by the present invention Figure 1 ;

[0022] Figure 2 A schematic diagram of the steps of a method for preparing an adjustable imprint master provided by the present invention Figure 2 ;

[0023] Figure 3 A schematic diagram of the steps of a method for preparing an adjustable imprint master provided by the present invention Figure 3 ;

[0024] Figure 4 A schematic diagram of the steps of a method for preparing an adjustable imprint master provided by the present invention Figure 4 ;

[0025] Figure 5 A schematic diagram of the steps of a method for preparing an adjustable imprint master provided by the present invention Figure 5 ;

[0026] Figure 6 A schematic diagram of the steps of a method for preparing an adjustable imprint master provided by the present invention Figure 6 ;

[0027] Figure 7 A schematic diagram of the structure of an adjustable imprint master provided by the present invention under modulation of a first voltage Figure 1 ;

[0028] Figure 8 Schematic diagram of the optical structure of an adjustable imprint master provided by the present invention under modulation of a first voltage Figure 2 ;

[0029] Fig. 9 A schematic diagram of a grating structure of an adjustable imprint master provided by the present invention under modulation of a first voltage;

[0030] Fig.10 A schematic diagram of a grating structure of an adjustable imprint master provided by the present invention under modulation of a second voltage;

[0031] Fig.11 A schematic flow chart of a method for preparing an adjustable imprint master provided by the present invention. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] Based on the technical problems pointed out in the background technology part, the present invention provides an adjustable imprint master and a method for making the same, so as to change the micro-nano structure of a local area of ​​the master to meet different design ID requirements, and to achieve adjustment of the period, duty cycle, height, and width of the micro-nano structure within a certain range, thereby improving the applicability and utilization rate of the master, shortening the design iteration cycle, saving production costs, and achieving cost reduction and efficiency improvement.

[0034] An adjustable imprint master, such as Figure 6As shown, a first material layer 10, an insulating layer 20, a first metal layer 30, a second material layer 40 and a second metal layer 50 are arranged in sequence; the second metal layer 50 is patterned to form a micro-nano structure in the second material layer 40, and the micro-nano structure is used for embossing to form an optical structure of an optical product; the micro-nano structure is displaced along a first direction under a first voltage modulation applied to the first material layer 10; and / or; the micro-nano structure is displaced along a second direction under a second voltage modulation applied to the first metal layer 30 and the second metal layer 50.

[0035] On the one hand, under the first voltage modulation applied to the first material layer 10, the micro-nano structure is displaced along the first direction.

[0036] In detail, Figure 6-7 As shown, Figure 7 As shown, the dotted line in the figure is Figure 6 When the first material layer 10 is applied with a first voltage, the micro-nano structure can be modulated to generate a displacement of a certain step length along the first direction, so that different micro-nano structures leave the relative position of the micro-nano structure when the first voltage is not applied. The first direction is defined as the direction in which the incident light propagates along the micro-nano structure in the first material layer. For example, it can include a direction parallel to the first material, such as including two directions along the micro-nano structure, such as Figure 6-7 The x and y directions shown in FIG. 1 are further explained as follows: Figure 7 As shown, when a first voltage is applied to the first material layer 10, the first material layer 10 can be deformed by a certain distance in the first direction, thereby driving the micro-nano structure located above the first material layer 10 to produce a corresponding displacement, so that the position of the changed micro-nano structure deviates from its original position; the first direction is parallel to the first material layer 10 and perpendicular to the optical height, that is, the X direction as shown in the figure, that is, the incident light propagates in a direction parallel to the first material layer 10 and perpendicular to the height of the micro-nano structure. In this embodiment, the micro-nano structure only undergoes a certain step-length displacement change, and the step-length can be controlled by controlling the magnitude of the first voltage.

[0037] Furthermore, for the size of the step size of the displacement of the micro-nano structure in the first direction, different step sizes are determined by controlling the size of the first voltage applied in the first direction according to the requirements of different imprinting masters; based on different first material layers, the voltage level that can be applied is mV~kV. For example, ±150mV~±1000V; according to the different sizes of the first voltage, the step size of the micro-nano structure leaving its original position can be controlled, such as 10nm~200nm, etc. In more detail, the displacement △L1=d1*V1 generated along the first direction is defined, where d1 represents the piezoelectric strain coefficient of the first material layer, and V1 is the size of the applied first voltage; the displacement △L2=d2*V2 generated along the second direction, where d2 represents the piezoelectric strain coefficient of the second material layer, and V2 is the size of the applied first voltage.

[0038] In another embodiment, further, Figure 8 As shown, the micro-nano structure also includes a change in the width direction of the micro-nano structure along the first direction under the modulation of the first voltage applied to the first material layer 10, so that the width of the micro-nano structure after the change is greater than the width of the micro-nano structure before the change, such as the width of the micro-nano structure is increased by 10%, 20%, 30%, 40%, 50% and so on compared with the original width. Based on different design IDs, the size of the width of the micro-nano structure can be adjusted, and the adjustment of the width of different micro-nano structures can be achieved by controlling the size of the first voltage; Figure 8 The middle dotted line shows the optical width when the first voltage is not applied. When the first voltage is applied, the optical width becomes larger.

[0039] Of course, in some other embodiments, it also includes controlling the reduction of the width of the micro-nano structure, such as reducing the width of the micro-nano structure by 10%, 20%, 30%, 40%, 50%, etc., compared to the original width of the micro-nano structure, which is controlled based on the properties of the first material layer and is available to those skilled in the art.

[0040] The optical product described in the present application is a diffraction optical element, such as a diffraction grating SRG, which includes a one-dimensional grating structure and / or a two-dimensional grating structure; and the micro-nano structure can be a DOE, and / or a diffuser, etc., which are diffraction micro-nano structures commonly used in the art and determined by a micro-nano imprinting process.

[0041] Figure 7 and Figure 8 Different embodiments of the present invention are derived from the precise control of the magnitude of the first voltage, which can control the magnitude of the first voltage, change the position of the micro-nano structure relative to its original position, and / or change the size of the micro-nano structure, such as parameters such as width and length, which is feasible.

[0042] Further, for each of the above embodiments, it also includes the following Fig. 9As shown in a and b in the figure, the change of the micro-nano structure is further described in detail. As an example, a diffraction grating is taken as an example, that is, a one-dimensional grating and a two-dimensional grating in the art. The figure shows a one-dimensional grating and a two-dimensional grating structure respectively. Of course, according to Fig. 9 The structure shown in the figure can also be understood as a common optical micro-nano device in the field such as a micro-nano wire grid, a microlens array, a DOE, a diffuser, etc. For ease of understanding, the embodiment of the present application takes a diffraction grating as an example for further explanation. The dotted line in the figure shows the size of the grating structure or the position of the grating structure when the first voltage is not applied; for a one-dimensional grating and a two-dimensional grating structure, it also includes controlling the size of the first voltage applied to the first material layer 10, so that the first material layer 10 is stretched in the third direction, thereby driving the grating structure to be stretched in the third direction to produce a certain step displacement, such as Fig. 9 The grating structure shown in a and b is stretched to produce a certain step displacement to adjust the length of the grating structure in the third direction; wherein the third direction is defined as a direction parallel to the first material layer and perpendicular to the first direction.

[0043] Furthermore, in combination with the above-mentioned various embodiments, Fig. 9 As shown in c and d, the grating structure can be stretched in a certain step length in the first direction and the third direction at the same time under the action of the first voltage of the first material layer 10. The figure shows a schematic diagram of the situation in which the width in the first direction and the length in the third direction are changed for different one-dimensional grating and two-dimensional grating structures at the same time; of course, the figure only shows the schematic situation in which the width in the first direction and the length in the third direction are stretched to increase the width and length of the grating; further, it can be known that it also includes the situation in which the width in the first direction and the length in the third direction are compressed to reduce the width and length of the grating.

[0044] Fig. 9 The grating structure shown in the figure is only a schematic diagram of one-dimensional grating and two-dimensional grating structure, and does not limit the specific structure of one-dimensional grating and two-dimensional grating. For example, grating structures of other shapes, such as blazed gratings, slant gratings, straight gratings, etc., or gratings with diamond and arc structures, the present invention does not limit the specific structure of this.

[0045] In the present invention, the first material layer is selected from piezoelectric ceramics (PZT) to achieve different deformations under different voltages, thereby driving the change of the grating structure; the insulating layer is used to isolate adjacent conductive layers to achieve conductivity control of different material layers, and can be selected from SiO2, Si3N4 or other insulating materials with the same function, and the present invention is not limited to this.

[0046] On the other hand, the micro-nano structure is displaced along the second direction under the second voltage modulation applied to the first metal layer 30 and the second metal layer 50. The second direction is a direction along the height of the micro-nano structure and away from the first material layer 10, that is, the second direction is a direction perpendicular to the first material layer 10, such as Figure 6 As shown, it is the Z-axis direction. Figure 6 ,like Fig.10 As shown, the dotted line in the figure is the size of the micro-nano structure when the second voltage is not applied, that is, Figure 6 The size of the micro-nano structure shown in , when a second voltage is applied in the second direction, under the modulation of the second voltage, the grating structure generates a displacement of a certain step length in the second direction, such as Fig.10 As shown, the height of the micro-nano structure increases, such as the height of the micro-nano structure increases by 10%, 20%, 30%, 40%, 50%, etc. compared to the original height.

[0047] Based on the adjustable ground, the magnitude of the second voltage is limited to mV to V, such as ±150mV to ±10V, so as to achieve precise control of the height of the micro-nano structure.

[0048] Fig.10 Only a schematic diagram of the increase in optical height under the action of the second voltage is shown. It can be known that based on the different properties of the optical material or the different control methods of the selected voltage, the height of the micro-nano structure can be reduced. It is known that the limitation of the width or length in the present invention includes two situations of increase or decrease.

[0049] Of course, in some other embodiments, the first voltage and the second voltage can work together to modulate the width, length, height and other parameters of the micro-nano structure in the first direction, the second direction and the third direction, and adjust the width, length and height of the micro-nano structure in different imprint masters to achieve changes in the period, duty cycle and height of the micro-nano structure; based on different design ID requirements, the magnitude of the voltage in different directions can be controlled to achieve modulation of different parameters. Based on this, the period, duty cycle and height of the micro-nano structure are adjusted within a certain range to improve the utilization rate of the imprint master, shorten the design iteration cycle, save production costs, and achieve cost reduction and efficiency improvement.

[0050] In any of the above embodiments, the first material layer 10 is selected from piezoelectric ceramics (PZT), such as lead zirconate titanate, to achieve different deformations under different voltages to drive the change of the micro-nano structure; the relevant parameters of the piezoelectric ceramics (PZT) are as follows:

[0051] Relative dielectric constant εref: 5400; loss factor: 200×10 -4 ; Coupling factor: K p =0.62, K 31 =0.34,K33 =0.68;

[0052] Pressure point coefficient: d 31 =-290pm / v,d 33 = +635pm / V;

[0053] Elastic compliance constant: S 33 E =18.1×10 -12 m 2 / N,S11 E =14.8×10 -12 m 2 / N

[0054] Frequency constant: radial = 2040 m / sec, thickness = 1800 m / sec, transverse = 1410 m / sec, longitudinal = 1370 m / sec;

[0055] Quality factor (resonance): 70;

[0056] Density:8g / cm 3 ; Bureau temperature: 150℃;

[0057] Specific heat: 380Ws / °Kkg;

[0058] Thermal conductivity: ca.1.5Ws / m·K (axial direction)

[0059] Thermal expansion coefficient: about -5ppm / ℃ (axial); about +5ppm / ℃ (lateral)

[0060] Of course, the above parameters will change significantly with changes in the operating electric field.

[0061] The insulating layer 20 is used to isolate the adjacent conductive layers to achieve the conductivity control of different material layers, and can be selected from, for example, SiO2; the first metal layer 30 can be selected from, for example, silver (Ag), gold (Au), copper (Cu), aluminum (Al), titanium (Ti); the second material layer 40 can be selected from, for example, gallium nitride (GaN), zinc oxide (ZnO); the second metal layer 50 can be selected from, for example, SiO2; the second metal layer 50 can be selected from, for example, silver (Ag), gold (Au), copper (Cu), aluminum (Al), titanium (Ti), and the material of the first metal layer can be the same or different. No specific and detailed limitation is made to this invention.

[0062] Furthermore, the thickness of the insulating layer is 50 to 200 nm; the thickness of the first metal layer is greater than 50 nm; the thickness of the second material layer is 20 to 200 nm, or even 200 nm to 300 nm, that is, the thickness of the second material layer is limited to 20 nm to 300 nm to adapt to different micro-nano structure height requirements; the thickness of the second metal layer ≥ the thickness of the second material layer * the etching selectivity ratio of one, and the etching selectivity ratio of one = the etching rate of the second metal layer / the etching rate of the second material layer.

[0063] At the same time, the present invention provides a method for preparing an adjustable imprint master, wherein the structure of the adjustable imprint master is as described in any of the above embodiments. Figures 1 to 5 As shown, in detail, the preparation method comprises:

[0064] (1) providing a first material layer 10, and sequentially disposing an insulating layer 20, a first metal layer 30, a second material layer 40, and a second metal layer 50 on the first material layer 10; and depositing a photoresist layer 60 on the surface of the second metal layer 50, and performing a patterning process on the photoresist layer 60; Figures 1-2 As shown;

[0065] (2) using the patterned photoresist layer as a mask layer, etching the second metal layer 50 to form a patterned second metal layer structure; removing the photoresist; Figure 3 As shown;

[0066] (3) Using the patterned second metal layer structure as a mask, the second material layer 40 is etched to obtain a micro-nano structure layer, such as Figure 4 As shown; and retaining the second metal layer structure, an adjustable imprinting master is obtained.

[0067] Through the above steps (1) to (3), a multi-layer material layer is first deposited on the first material layer 10, and then etched to form an adjustable imprint master with a multi-layer structure through UV exposure, electron beam direct writing or laser direct writing, ICP, RIBE and other process methods. The flow diagram of the preparation method is shown in FIG. Fig.11 shown.

[0068] In step (1), the thickness of the insulating layer is 50-200 nm; the thickness of the first metal layer is greater than 50 nm; the thickness of the second material layer is 20-200 nm, or even 200 nm-300 nm, to adapt to different grating height requirements;

[0069] The thickness of the second metal layer 50 ≥ the thickness of the second material layer*the etching selectivity ratio of 1, where the etching selectivity ratio of 1=the etching rate of the second metal layer / the etching rate of the second material layer;

[0070] The thickness of the photoresist layer 60 ≥ the thickness of the second metal layer * etching selectivity ratio 2, where etching selectivity ratio 2 = etching rate of the photoresist layer / etching rate of the second metal layer;

[0071] like Figure 5 As shown, after step (3), step (4) is also included, in which electrode sheets are arranged at both ends of the first material layer 10 and electrically connected, and the deformation displacement of the first material layer 10 in the first direction and the third direction is achieved by controlling the voltage.

[0072] Further, the method further includes step (5), setting and controlling the voltage at both ends of the first metal layer 30 and the second metal layer 50, that is, at both ends of the grating structure, so that the height of the micro-nano structure layer increases or decreases, such as Figure 6 shown.

[0073] Based on the adjustable imprint master prepared in the steps of the present invention, the parameters of the micro-nano structures at different positions can be controlled based on the first material layer, the first metal layer and the second metal layer to achieve modulation of the period, duty cycle, width and other parameters of the micro-nano structures. According to different design IDs, different first voltages and second voltages are determined to control their different positions respectively, so as to adapt to application scenarios when multiple micro-nano structures change.

[0074] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An adjustable imprint master, characterized in that: The method comprises a first material layer, an insulating layer, a first metal layer, a second material layer and a second metal layer which are arranged in sequence; the second metal layer is patterned to form a micro-nano structure in the second material layer, and the micro-nano structure is used for embossing to form an optical structure of an optical product; The micro-nano structure is displaced along a first direction under a first voltage modulation applied to the first material layer; and / or the micro-nano structure is displaced along a second direction under a second voltage modulation applied to the first metal layer and the second metal layer; the first direction is the direction in which the incident light propagates along the micro-nano structure and in the first material layer; the second direction is the direction along the height of the micro-nano structure and away from the first material layer.

2. The adjustable imprint master according to claim 1, characterized in that: The width of the micro-nano structure in the first direction increases or decreases; and / or; the height of the micro-nano structure in the second direction increases or decreases.

3. The adjustable imprint master according to any one of claims 1 to 2, characterized in that: The first voltage and the second voltage are the same or different; the displacement Δ generated along the first direction L1=d1*V1, where d1 represents the piezoelectric strain coefficient of the first material layer, and V1 is the magnitude of the applied first voltage; the displacement △L2 generated along the second direction=d2*V2, where d2 represents the piezoelectric strain coefficient of the second material layer, and V2 is the magnitude of the applied second voltage.

4. The adjustable imprint master according to any one of claims 1 to 2, characterized in that: A third direction is also included, and the length of the micro-nano structure increases or decreases in the third direction. The third direction is parallel to the first material layer and perpendicular to the first direction.

5. The adjustable imprint master according to claim 1 or 4, characterized in that: The first material layer is piezoelectric ceramic; the insulating layer is SiO2 or Si3N4.

6. The adjustable imprint master according to claim 1 or 4, characterized in that: The thickness of the second metal layer ≥ the thickness of the second material layer * etching selectivity ratio 1, etching selectivity ratio 1 = etching rate of the second metal layer / etching rate of the second material layer; the thickness of the photoresist layer ≥ the thickness of the second metal layer * etching selectivity ratio 2, etching selectivity ratio 2 = etching rate of the photoresist layer / etching rate of the second metal layer.

7. The adjustable imprint master according to claim 6, characterized in that: The optical structure is a diffractive optical structure, and the diffractive optical structure may be a one-dimensional grating structure and / or a two-dimensional grating structure; or the diffractive optical structure is a DOE or a Diffuser.

8. A method for preparing an adjustable imprint master, characterized in that: The steps include: (1) providing a first material layer, and sequentially arranging an insulating layer, a first metal layer, a second material layer, and a second metal layer on the first material layer; and depositing a photoresist layer on a surface of the second metal layer, and performing patterning on the photoresist layer; (2) using the patterned photoresist layer as a mask layer, etching the second metal layer to form a patterned second metal layer structure; and removing the photoresist; (3) using the patterned second metal layer structure as a mask, etching the second material layer to obtain a micro-nano structure layer; The second metal layer structure is retained to obtain an adjustable imprint master.

9. The preparation method according to claim 8, characterized in that: Furthermore, the method further comprises step (4), wherein electrode sheets are provided at both ends of the first material layer and electrically connected to each other, and the deformation displacement of the first material layer in the first direction and the third direction is achieved by controlling the voltage.

10. The preparation method according to any one of claims 8 to 9, characterized in that: Furthermore, the method further comprises step (5), applying and controlling voltage at both ends of the first metal layer and the second metal layer so that the height of the micro-nano structure layer increases or decreases.

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