Manufacturing method for blazed grating

Abstract

The present application provides a manufacturing method for a blazed grating. The method comprises: providing a substrate, wherein the substrate is covered with periodically arranged masks; and by using an incident angle and a rotation angle, and by using the masks for masking, etching the substrate by means of an ion beam to form a blazed grating. The incident angle is an angle between a first projection of the ion beam on a plane where a normal of the substrate is located and the normal of the substrate, the rotation angle is an angle between a second projection of the ion beam on a plane where the surface of the substrate is located and a tangent of the surface of the substrate, and an anti-blaze angle of the blazed grating is determined on the basis of the incident angle and the rotation angle. In this way, by using the incident angle and the rotation angle, the masking effect of the masks can be reduced, achieving the objective of controlling the anti-blaze angle, and realizing controllability of the anti-blaze angle; thus, by controlling the incident angle and the rotation angle, the anti-blaze angle is increased, and the diffraction efficiency of the blazed grating is finally improved.

Description

Method for manufacturing a blazed grating

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 6, 2023, with application number 202311149415.0 and invention name “A method for manufacturing a blazed grating”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of semiconductors, and in particular to a method for manufacturing a blazed grating. Background Art

[0003] With the rapid development of semiconductor technology, blazed gratings are becoming increasingly widely used. For example, blazed gratings can be applied in augmented reality or virtual reality scenarios, such as optical transmissive near-eye display technologies included in augmented reality or virtual reality scenarios.

[0004] Theoretically, the diffraction efficiency of the +1 order of the blazed grating is 100%, but in reality, the diffraction efficiency of the +1 order of the blazed grating is only 65%-80%. This is because the anti-blaze angle of the blazed grating is not vertical, resulting in part of the light being absorbed or reflected.

[0005] Therefore, there is an urgent need for a method to improve the diffraction efficiency of a blazed grating.

[0006] Summary of the Invention

[0007] In view of this, the purpose of the present application is to provide a method for manufacturing a blazed grating, which can increase the anti-blaze angle and improve the diffraction efficiency of the blazed grating.

[0008] The present application provides a method for manufacturing a blazed grating, the method comprising:

[0009] Providing a substrate, wherein the substrate is covered with periodically arranged masks;

[0010] By utilizing the incident angle and the rotation angle, the mask is used as a mask and the substrate is etched with an ion beam to form a blazed grating; the incident angle is the angle between the first projection of the ion beam on the plane where the normal of the substrate is located and the normal of the substrate, and the rotation angle is the angle between the second projection of the ion beam on the plane where the surface of the substrate is located and the tangent of the surface of the substrate. The anti-blaze angle of the blazed grating is determined according to the incident angle and the rotation angle.

[0011] Optionally, the periodically arranged mask includes a mask period, a mask line width, and a mask height; the blazed grating includes a blaze angle, a reverse blaze angle, and a grating height;

[0012] The reverse blaze angle of the blazed grating is determined according to the incident angle and the rotation angle, comprising:

[0013] Wherein, α is the rotation angle, β is the blaze angle, γ is the anti-blaze angle, θ is the incident angle, a is the mask period, b is the mask line width, and h is the mask height.

[0014] Optionally,

[0015] Optionally, the ratio of the mask etching rate to the substrate etching rate is k;

[0016] Optionally,

[0017] Wherein, h1 is the grating height.

[0018] Optionally, the direction of the acute angle formed by the ion beam and the plane where the surface of the substrate is located is the same as the direction of the blaze angle.

[0019] Optionally, the mask period is in the range of [200 nanometers, 10 micrometers], the mask line width is in the range of [5%, 80%] of the mask period, and the mask height is greater than or equal to the product of the grating height and k.

[0020] Optionally, the rotation angle is not 0.

[0021] Optionally, the rotation angle has an angle range of [-90°, 90°].

[0022] Optionally, the material of the mask is the same as that of the substrate.

[0023] Optionally, the material of the substrate may be one or more of Al2O3, Ga2O3, Ta2O3, Si, SiO2, Si3N4, quartz and TiO2.

[0024] Optionally, when the rotation angle is determined, the positive or negative value of the incident angle affects the direction of the blaze angle, but does not affect the size of the blaze angle, the size of the anti-blaze angle, and the size of the grating height.

[0025] Optionally, when the incident angle is determined, the positive or negative sign of the rotation angle does not affect the direction of the blaze angle, the size of the blaze angle, the size of the anti-blaze angle, and the size of the grating height.

[0026] Optionally, when the rotation angle is 0, the lateral etching rate of the substrate is greater than when the rotation angle is not 0.

[0027] Optionally, the method further includes:

[0028] A first etching gas is introduced into the discharge chamber, and a second etching gas is introduced into the etching chamber. The substrate is located in the etching chamber, and the first etching gas is used to form plasma.

[0029] Optionally, the first etching gas includes one or more of an inert gas, a fluorine-based gas, a chlorine-based gas, a bromine-based gas, nitrogen or oxygen, and the second etching gas includes one or more of a fluorine-based gas, a chlorine-based gas, a bromine-based gas or oxygen.

[0030] Optionally, the gas flow rate range of the first etching gas is [10 sccm, 200 sccm], and the gas flow rate range of the second etching gas is [50 sccm, 5000 sccm].

[0031] Optionally, the beam energy range is [50V, 600V].

[0032] Optionally, the accelerating voltage is 20% of the beam energy.

[0033] Optionally, the beam current range is [50mA, 1200mA].

[0034] The present application provides a method for manufacturing a blazed grating, the method comprising: providing a substrate, the substrate being covered with a periodically arranged mask, utilizing an incident angle and a rotation angle, using the mask as a mask, and etching the substrate with an ion beam to form a blazed grating. The incident angle is the angle between the first projection of the ion beam on the plane where the normal of the substrate is located and the normal of the substrate, and the rotation angle is the angle between the second projection of the ion beam on the plane where the surface of the substrate is located and the tangent of the surface of the substrate. The anti-blaze angle of the blazed grating is determined according to the incident angle and the rotation angle. In this way, by utilizing the incident angle and the rotation angle, the shielding effect of the mask can be reduced, thereby achieving the purpose of controlling the angle of the anti-blaze angle, realizing the controllability of the anti-blaze angle, thereby increasing the angle of the anti-blaze angle by controlling the incident angle and the rotation angle, and ultimately improving the diffraction efficiency of the blazed grating. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] FIG1 is a schematic flow chart showing a method for manufacturing a blazed grating according to an embodiment of the present application;

[0037] FIG2 is a schematic structural diagram showing a manufacturing process of a blazed grating provided in an embodiment of the present application;

[0038] FIG3 is a schematic diagram showing an incident angle provided by an embodiment of the present application;

[0039] FIG4 is a schematic diagram showing a rotation angle provided by an embodiment of the present application;

[0040] FIG5 shows a schematic cross-sectional structure diagram of a substrate and a mask provided in an embodiment of the present application;

[0041] FIG6 shows a schematic cross-sectional structure diagram of a blazed grating provided in an embodiment of the present application;

[0042] FIG7 shows a schematic cross-sectional structure diagram of another blazed grating provided in an embodiment of the present application;

[0043] FIG8 shows a schematic cross-sectional structure diagram of another blazed grating provided in an embodiment of the present application;

[0044] FIG9 shows a schematic cross-sectional structure diagram of another blazed grating provided in an embodiment of the present application;

[0045] FIG10 shows a schematic cross-sectional structure diagram of another blazed grating provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0048] This application is described in detail with reference to schematic diagrams. When describing the embodiments of this application, for ease of explanation, cross-sectional views of device structures may be partially enlarged and not to scale. Furthermore, these schematic diagrams are merely illustrative and should not limit the scope of protection of this application. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0049] With the rapid development of semiconductor technology, optical transmissive near-eye display technology included in augmented reality or virtual reality scenarios has also been vigorously developed. Optical transmissive near-eye display technology includes grating waveguide technology. Grating waveguide uses the multi-slit diffraction of the grating to disperse light and the total internal reflection characteristics of the waveguide medium to realize the transmission of the imaging light beam. When the light is incident on the grating surface at a certain angle, the grating will perform spatial periodic modulation on the amplitude or phase of the incident light wave, and the light will diffract out of the grating surface in several different directions. Because grating waveguides have the advantages of large field of view, good display effect, small size, light weight, and low mass production cost, they are considered to be the preferred optical solution for consumer-grade augmented reality glasses or virtual reality glasses. However, the development of grating waveguides is also subject to some limitations, such as relatively low optical efficiency and serious light efficiency loss.

[0050] Blazed gratings can be used in augmented reality or virtual reality scenarios. Blazed gratings are phase gratings that separate the central maximum diffraction from a single groove facet from the zero-order interference maximum between the groove faces, thereby concentrating light energy on the desired first-order diffraction spectrum. Due to their zero-order splitting and readily satisfying missing orders, they achieve high diffraction efficiency. Theoretically, the +1st-order diffraction efficiency of a blazed grating is 100%, but in practice, the +1st-order diffraction efficiency is only 65%-80%. This is because the blazed grating's non-perpendicular anti-blaze angle causes some light to be absorbed or reflected.

[0051] There are currently two methods for producing blazed gratings. One involves transferring a prefabricated blazed grating template onto a photoresist through "pattern transfer," and then completely transferring the pattern to the etched material through vertical chemical etching. However, this method typically results in arc-shaped corner connections, making it impossible to obtain a blazed grating with a perpendicular anti-blazed surface. The other method involves carving grooves into the etched material through "mechanical scribing." However, this is an ultra-precision machining technique that requires extremely high mechanical and working environment requirements. Any slight disturbance will result in a loss of precision, making mass production extremely difficult.

[0052] Therefore, there is an urgent need for a method to improve the diffraction efficiency of a blazed grating.

[0053] Based on this, the present application provides a method for manufacturing a blazed grating, the method comprising: providing a substrate, the substrate being covered with a periodically arranged mask, utilizing an incident angle and a rotation angle, using the mask as a mask, and etching the substrate with an ion beam to form a blazed grating. The incident angle is the angle between the first projection of the ion beam on the plane where the normal of the substrate is located and the normal of the substrate, and the rotation angle is the angle between the second projection of the ion beam on the plane where the surface of the substrate is located and the tangent of the surface of the substrate. The anti-blaze angle of the blazed grating is determined according to the incident angle and the rotation angle. In this way, by utilizing the incident angle and the rotation angle, the shielding effect of the mask can be reduced, thereby achieving the purpose of controlling the angle of the anti-blaze angle, realizing the controllability of the anti-blaze angle, thereby increasing the angle of the anti-blaze angle by controlling the incident angle and the rotation angle, and ultimately improving the diffraction efficiency of the blazed grating.

[0054] In order to better understand the technical solutions and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0055] See FIG1 , which is a schematic flow chart of a method for manufacturing a blazed grating provided in an embodiment of the present application.

[0056] The method for manufacturing a blazed grating provided in this embodiment can be applied to semiconductor devices, such as ion beam etching (IBE) equipment. The IBE equipment includes a discharge chamber and an etching chamber. The discharge chamber is used to introduce a first etching gas, which is ionized into a plasma and then drawn through a grid into the etching chamber. The plasma is then neutralized by electrons generated by a neutralizer, thereby achieving etching. Simultaneously, a second etching gas is introduced into the etching chamber to assist in the etching process.

[0057] The method for manufacturing the blazed grating provided in this embodiment includes the following steps:

[0058] S101, providing a substrate.

[0059] In the embodiments of the present application, the substrate may be a dielectric material or a high refractive index material, for example, the substrate material may be one or more of Al2O3, Ga2O3, Ta2O3, Si, SiO2, Si3N4, quartz, and TiO2.

[0060] The substrate may be covered with a patterned mask, which is arranged periodically, so that a periodic blazed grating can be formed using the periodically arranged mask.

[0061] Referring to FIG2 , FIG2 is a schematic diagram of the structure of a blazed grating during the manufacturing process at a certain angle (Angled View), wherein the material is a substrate and the masks are arranged periodically. The substrate is placed in an etching chamber.

[0062] In the embodiments of the present application, the mask material can be the same as the substrate material, in which case the mask is a homogeneous mask. For example, the substrate material is Si and the mask material is Si. The mask material can be different from the substrate material, in which case the mask is a heterogeneous mask. For example, the substrate material is Si and the mask material is photoresist.

[0063] S102, utilizing the incident angle and the rotation angle, using the mask as a mask, and utilizing the ion beam to etch the substrate to form a blazed grating.

[0064] In embodiments of the present application, an ion beam extracted from a discharge chamber can be used to etch a substrate. The incident ion beam can be referred to as an ion beam. Specifically, the substrate can be etched using a mask using an incident angle and a rotation angle, thereby forming a blazed grating.

[0065] When an ion beam etches a masked substrate at an oblique angle of incidence, different locations of the substrate are etched to varying degrees due to the obstruction of the mask. The portion of the substrate not obstructed by the mask is preferentially etched downward, while the remaining substrate is gradually etched as the mask disappears. As the mask is completely consumed, a blazed grating with a certain groove pattern is formed. The angle of incidence is the angle between the first projection of the ion beam onto the plane of the substrate normal and the substrate normal. Figure 3 shows a schematic cross-sectional view of a blazed grating during fabrication. The dotted line perpendicular to the substrate represents the substrate normal, and the angle of incidence is θ.

[0066] However, when the substrate is actually etched at an inclined incident angle, the shielding effect of the mask is strong, resulting in a smaller anti-blaze angle of the blazed grating. Therefore, the substrate can be etched in combination with a rotation angle. The rotation angle is the angle between the second projection of the ion beam on the plane where the surface of the substrate is located and the tangent of the surface of the substrate. Refer to Figure 4, which is a top-down schematic diagram of the blazed grating during the manufacturing process. The dotted line at right angles to the mask is the tangent of the surface of the substrate, and the rotation angle is α.

[0067] That is to say, by combining the direction of the ion beam with the rotation angle based on the incident angle, the shielding effect of the mask can be reduced, and the lateral etching rate can be changed without changing the longitudinal etching rate of the etched material, ultimately achieving the controllable angle of the anti-blaze angle, that is, realizing the controllable angle of the anti-blaze angle.

[0068] In the embodiments of the present application, the anti-blaze angle of the blazed grating can be determined according to the incident angle and the rotation angle. That is, the anti-blaze angle can be increased by controlling the incident angle and the rotation angle, thereby ultimately improving the diffraction efficiency of the blazed grating.

[0069] In practical applications, the substrate is etched simultaneously by combining the incident angle and the rotation angle, that is, the substrate is etched once by utilizing the incident angle and the rotation angle.

[0070] Specifically, the structural parameters of the periodic mask include mask period, mask line width, and mask height. As shown in Figure 5 , the substrate material is Si, the mask material is Si, the mask height is 600 nm, the mask line width is 80 nm, and the mask period is 400 nm.

[0071] The structural parameters of the blazed grating include the blaze angle, anti-blaze angle and grating height.

[0072] The anti-blaze angle can be calculated using the following formula:

[0073] Among them, α is the rotation angle, β is the blaze angle, γ is the anti-blaze angle, θ is the incident angle, a is the mask period, b is the mask line width, and h is the mask height.

[0074] In the above formula, 0≤c≤ab, when c=0, γ=90°, and when 0<c<ab, γ<90°. In other words, when c=0, the anti-blaze angle is 90°. In this way, the optimal incident angle and optimal rotation angle can be reversed by the expected anti-blaze angle, and the substrate can be subsequently etched using the optimal incident angle and optimal rotation angle to ultimately achieve an anti-blaze angle of 90°.

[0075] In an embodiment of the present application, the rotation angle is not 0, that is, α≠0. When the rotation angle is 0, the second projection of the ion beam on the substrate surface coincides with the tangent of the substrate surface, and the substrate is still etched at the incident angle. At this time, a small anti-blaze angle still occurs.

[0076] In the embodiments of the present application, the lateral etching rate of the substrate when the rotation angle is 0 is greater than the lateral etching rate of the substrate when the rotation angle is not 0. In other words, compared with etching the substrate without setting the rotation angle, the lateral etching rate of the substrate is reduced after the rotation angle is set, which helps to form an anti-blaze angle close to 90°.

[0077] In practical applications, the lower electrode in the etching chamber can rotate to control the rotation angle. The rotation angle range is [-90°, 90°] and the rotation angle is not 0.

[0078] The lower electrode in the etching chamber can be revolved to control the angle of incidence, which ranges from -90° to 90°. Due to limitations of the etching chamber, the revolving electrode can only operate in the third and fourth quadrants. That is, when the angle of incidence is 0, the first projection of the ion beam onto the plane of the substrate normal coincides with the substrate normal.

[0079] In practice, when the substrate lines form an angle of 1° with the perpendicular direction of the ion beam, the lower electrode needs to be rotated -1°. This ensures that the substrate lines remain parallel to the perpendicular direction of the ion beam, facilitating subsequent calculations of the incident and rotation angles.

[0080] In practical applications, when When the mask has no shielding effect, setting the rotation angle is meaningless. Therefore, the incident angle can be kept to satisfy the above relationship, thus achieving an anti-blaze angle close to 90°.

[0081] In the embodiment of the present application, when α is the rotation angle, β is the blaze angle, γ is the anti-blaze angle, θ is the incident angle, a is the mask period, b is the mask line width, and h is the mask height, the grating height of the blazed grating can be obtained according to the blaze angle, the anti-blaze angle, and the mask period. The specific formula is as follows:

[0082] Where h1 is the grating height.

[0083] In the embodiments of the present application, the materials of the substrate and mask affect the ratio of the mask etching rate to the substrate etching rate. If the ratio of the mask etching rate to the substrate etching rate is k, then the mask height is greater than or equal to the product of the grating height and k, that is, h ≥ kh1, where k is in the range [0.1, 15].

[0084] In the embodiment of the present application, the blaze angle can be determined according to the incident angle and the ratio of the mask etching rate to the substrate etching rate, specifically referring to the following formula:

[0085] In practical applications, the mask period ranges from [200 nm, 10 μm], i.e., the mask period ranges from 200 nm to 10 μm. The mask line width ranges from [5%, 80%] of the mask period, i.e., the mask line width ranges from 5% to 80% of the mask period.

[0086] In the embodiments of the present application, the direction of the acute angle formed by the ion beam and the plane of the substrate surface is the same as the direction of the blaze angle. In other words, the incident direction of the ion beam affects the direction of the blaze angle, and thus the direction of the blaze angle can be adjusted by adjusting the direction of the ion beam.

[0087] In the embodiments of the present application, when the incident angle is determined, the positive or negative sign of the rotation angle does not affect the direction, magnitude, or anti-blaze angle of the blaze angle, or the grating height. In other words, the positive or negative sign of the rotation angle does not substantially affect the blazed grating. Specifically, as long as the second projection of the ion beam on the substrate's surface plane forms a fixed angle with the tangent line to the substrate's surface, the direction, magnitude, or anti-blaze angle of the blaze angle, or the grating height, does not affect the blaze angle, magnitude, or anti-blaze angle of the blaze angle, or the grating height, regardless of whether the second projection of the ion beam on the substrate's surface plane is on either side of the tangent line.

[0088] In the embodiments of the present application, when the rotation angle is determined, the positive or negative sign of the incident angle affects the direction of the blaze angle, but does not affect the magnitude of the blaze angle, the magnitude of the reverse blaze angle, or the size of the grating height. In other words, the positive or negative sign of the incident angle only affects the direction of the blaze angle, and has no effect on the magnitude of the blaze angle, the magnitude of the reverse blaze angle, or the size of the grating height. In other words, as long as the first projection of the ion beam on the plane containing the substrate normal forms a fixed angle with the substrate normal, the first projection of the ion beam on the plane containing the substrate normal does not affect the magnitude of the blaze angle, the magnitude of the reverse blaze angle, or the size of the grating height.

[0089] In an embodiment of the present application, to etch the substrate, a first etching gas may be introduced into the discharge chamber and a second etching gas may be introduced into the etching chamber, thereby etching the substrate using the first etching gas and the second etching gas.

[0090] Specifically, the first etching gas includes one or more of an inert gas, a fluorine-based gas, a chlorine-based gas, a bromine-based gas, nitrogen, or oxygen. The second etching gas includes one or more of a fluorine-based gas, a chlorine-based gas, a bromine-based gas, or oxygen. The inert gas may include He, Ne, Ar, Kr, and Xe. The fluorine-based gas may include CF4, CF8, CHF3, BF3, and SF6. The chlorine-based gas may include HCl, CCl4, BCl3, and Cl2. The bromine-based gas may include HBr, etc.

[0091] In practical applications, the gas flow rate range of the first etching gas is [10 sccm, 200 sccm], which can achieve a pressure of 0.1-5 mtor in the discharge chamber, thereby increasing the mean free path of ions and facilitating etching.

[0092] The gas flow range of the second etching gas is [50 sccm, 5000 sccm], which can achieve a pressure of 0.1-10 mtor in the etching chamber, thereby increasing the mean free path of ions and facilitating etching.

[0093] In the embodiment of the present application, the beam energy range is [50 V, 600 V]. The greater the beam energy, the greater the productivity. However, too high a beam energy will increase the sidewall damage. Therefore, the beam energy can be selected according to the actual situation.

[0094] In the embodiment of the present application, the acceleration voltage is 20% of the beam energy, which can keep the beam divergence angle at 5°-15°, improve the ion utilization rate in the plasma, and facilitate etching.

[0095] In the embodiment of the present application, the beam current range is [50mA, 1200mA]. The larger the beam current, the greater the productivity. However, too high a beam current will increase the sidewall damage. Therefore, the beam current can be selected according to the actual situation.

[0096] In practical applications, the beam current generated by the neutralizer is equal to the beam current of the first etching gas, which can achieve complete neutralization, reduce charge accumulation, keep the beam divergence angle at 5°-15°, improve the ion utilization rate in the plasma, and facilitate etching.

[0097] The following are five methods for adjusting the structural parameters of the blazed grating at different incident angles and rotation angles when etching the substrate:

[0098] The first condition uses Si as a homogeneous mask with a mask height of 600nm, a mask line width of 80nm, and a mask period of 400nm. The incident angle is 40°, and the rotation angle is 0. The first etching gas is Ar, with an Ar gas flow rate of 24sccm, a beam energy of 400V, an acceleration voltage of 80V, and a beam current of 510mA. After ionizing Ar to form a plasma, it is neutralized through a grid and the substrate is etched for 420s. The resulting blazed grating has a grating height of 270nm, a blaze angle of 57°, and a reverse blaze angle of 50°, as shown in Figure 6.

[0099] The second condition is to use Si as a homogeneous mask with a mask height of 600nm, a mask line width of 80nm, and a mask period of 400nm. The incident angle is 35° and the rotation angle is 49°. The first etching gas is Ar, and the Ar gas flow rate is set to 24sccm, the beam energy is 400V, the acceleration voltage is 80V, and the beam current is 510mA. After the Ar is ionized to form a plasma, it is neutralized by the grid and the substrate is etched for 315s. The grating height of the formed blazed grating is 213nm, the blaze angle is 31°, and the anti-blaze angle is 78°, as shown in Figure 7. Based on the anti-blaze angle of 78° and the formula, the theoretical rotation angle is 49.16°, which is very close to the rotation angle of the second condition. Compared with the first condition, under the same mask morphology and the same incident angle, the anti-blaze angle can be increased by adding a rotation angle, that is, the verticality of the anti-blaze angle can be increased.

[0100] The third condition is to use Si as a homogeneous mask with a mask height of 600nm, a mask line width of 80nm, and a mask period of 400nm. The incident angle is 35° and the rotation angle is 41°. The first etching gas is Ar, and the Ar gas flow rate is set to 24sccm, the beam energy is 400V, the acceleration voltage is 80V, and the beam current is 510mA. After the Ar is ionized to form a plasma, it is neutralized by the grid and the substrate is etched for 342s. The grating height of the formed blazed grating is 240nm, the blaze angle is 31°, and the anti-blaze angle is 89°, as shown in Figure 8. Based on the anti-blaze angle of 89° and the inverse formula, the theoretical rotation angle is 40.4°, which is very close to the rotation angle of the third condition. Compared with the second condition, under the same mask morphology and the same incident angle, the anti-blaze angle can be increased by adjusting the rotation angle, so that the anti-blaze surface of the blazed grating is completely close to vertical.

[0101] The fourth condition is to use Si as a homogeneous mask with a mask height of 600nm, a mask line width of 80nm, and a mask period of 400nm. The incident angle is 40° and the rotation angle is 51°. The first etching gas is Ar, and the Ar gas flow rate is set to 24sccm, the beam energy is 400V, the acceleration voltage is 80V, and the beam current is 510mA. After the Ar is ionized to form a plasma, it is neutralized by the grid and the substrate is etched for 354s. The grating height of the formed blazed grating is 269nm, the blaze angle is 34°, and the anti-blaze angle is 89°, as shown in Figure 9. Based on the anti-blaze angle of 89° and the inverse formula, the theoretical rotation angle is 50.53°, which is very close to the rotation angle of the fourth condition. Compared with the third condition, under the same mask morphology, by adjusting the incident angle and rotation angle, blazed gratings with different blaze angles and an anti-blaze angle close to 90° can be obtained.

[0102] The fifth condition is to use Si as a homogeneous mask with a mask height of 450nm, a mask line width of 60nm, and a mask period of 320nm. The incident angle is 34° and the rotation angle is 31°. The first etching gas is Ar, and the Ar gas flow rate is set to 24sccm, the beam energy is 400V, the acceleration voltage is 80V, and the beam current is 510mA. After the Ar is ionized to form a plasma, it is neutralized by the grid and the substrate is etched for 270s. The grating height of the formed blazed grating is 168nm, the blaze angle is 28°, and the anti-blaze angle is 89°, as shown in Figure 10. According to the anti-blaze angle of 89° and the inverse formula, the theoretical rotation angle is 31.1°, which is very close to the rotation angle of the fifth condition. Comparing the third and fourth conditions, under different mask morphologies, blazed gratings with different blaze angles and anti-blaze angles close to 90° can be obtained by adjusting the incident angle and the rotation angle, that is, the blaze angle and anti-blaze angle of the blazed grating can be controlled by using the incident angle and the rotation angle.

[0103] It can be seen that the present application provides a method for manufacturing a blazed grating, the method comprising: providing a substrate, the substrate being covered with a periodically arranged mask, utilizing an incident angle and a rotation angle, using the mask as a mask, and etching the substrate with an ion beam to form a blazed grating. The incident angle is the angle between the first projection of the ion beam on the plane where the normal of the substrate is located and the normal of the substrate, and the rotation angle is the angle between the second projection of the ion beam on the plane where the surface of the substrate is located and the tangent of the surface of the substrate. The anti-blaze angle of the blazed grating is determined according to the incident angle and the rotation angle. In this way, by utilizing the incident angle and the rotation angle, the shielding effect of the mask can be reduced, thereby achieving the purpose of controlling the angle of the anti-blaze angle, realizing the controllability of the anti-blaze angle, thereby increasing the angle of the anti-blaze angle by controlling the incident angle and the rotation angle, and ultimately improving the diffraction efficiency of the blazed grating.

[0104] The above is only a preferred embodiment of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of protection of the technical solution of the present application.

Claims

1. A method for manufacturing a blazed grating, characterized in that: The method comprises: Providing a substrate, wherein the substrate is covered with periodically arranged masks; By utilizing the incident angle and the rotation angle, the mask is used as a mask and the substrate is etched using an ion beam to form a blazed grating; the incident angle is the angle between a first projection of the ion beam on a plane where the normal of the substrate is located and the normal of the substrate, and the rotation angle is the angle between a second projection of the ion beam on a plane where the surface of the substrate is located and a tangent to the surface of the substrate, and the anti-blazed angle of the blazed grating is determined based on the incident angle and the rotation angle.

2. The manufacturing method according to claim 1, characterized in that: The periodically arranged mask includes a mask period, a mask line width and a mask height; the blazed grating includes a blaze angle, a reverse blaze angle and a grating height; The reverse blaze angle of the blazed grating is determined according to the incident angle and the rotation angle, comprising: Among them, α is the rotation angle, β is the blaze angle, γ is the anti-blaze angle, θ is the incident angle, a is the mask period, b is the mask line width, and h is the mask height.

3. The manufacturing method according to claim 2, characterized in that:

4. The manufacturing method according to claim 2, characterized in that: The ratio of the mask etching rate to the substrate etching rate is k; 5. The manufacturing method according to claim 2, characterized in that: Wherein, h1 is the grating height.

6. The manufacturing method according to claim 2, characterized in that: The direction of the acute angle formed by the ion beam and the plane where the surface of the substrate is located is the same as the direction of the blaze angle.

7. The manufacturing method according to claim 4, characterized in that: The range of the mask period is [200 nanometers, 10 micrometers], the range of the mask line width is [5%, 80%] of the mask period, and the mask height is greater than or equal to the product of the grating height and k.

8. The manufacturing method according to claim 1, characterized in that: The rotation angle is not 0.

9. The manufacturing method according to claim 8, characterized in that: The rotation angle has an angle range of [-90°, 90°].

10. The manufacturing method according to claim 1, characterized in that: The material of the mask is the same as that of the substrate.

11. The manufacturing method according to claim 10, characterized in that: The material of the substrate may be one or more of Al2O3, Ga2O3, Ta2O3, Si, SiO2, Si3N4, quartz and TiO2.

12. The manufacturing method according to claim 2, characterized in that: When the rotation angle is determined, the positive or negative value of the incident angle affects the direction of the blaze angle, but does not affect the size of the blaze angle, the size of the anti-blaze angle, and the size of the grating height.

13. The manufacturing method according to claim 2, characterized in that: When the incident angle is determined, the positive or negative value of the rotation angle does not affect the direction of the blaze angle, the size of the blaze angle, the size of the anti-blaze angle, and the size of the grating height.

14. The manufacturing method according to claim 1, characterized in that: When the rotation angle is 0, the lateral etching rate of the substrate is greater than the lateral etching rate of the substrate when the rotation angle is not 0.

15. The manufacturing method according to claim 1, characterized in that: The method further comprises: A first etching gas is introduced into the discharge chamber, and a second etching gas is introduced into the etching chamber. The substrate is located in the etching chamber, and the first etching gas is used to form plasma.

16. The manufacturing method according to claim 1, characterized in that: The first etching gas includes one or more of an inert gas, a fluorine-based gas, a chlorine-based gas, a bromine-based gas, nitrogen or oxygen, and the second etching gas includes one or more of a fluorine-based gas, a chlorine-based gas, a bromine-based gas or oxygen.

17. The manufacturing method according to claim 16, characterized in that: The gas flow rate range of the first etching gas is [10 sccm, 200 sccm], and the gas flow rate range of the second etching gas is [50 sccm, 5000 sccm].

18. The manufacturing method according to claim 16, characterized in that: The beam energy range is [50V, 600V].

19. The manufacturing method according to claim 18, characterized in that: The accelerating voltage was 20% of the beam energy.

20. The manufacturing method according to claim 1, characterized in that: The beam current range is [50mA, 1200mA].

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