Grating manufacturing method and grating ruler

Abstract

The present invention belongs to the technical field of optical elements, and discloses a grating manufacturing method and a grating ruler, wherein the grating manufacturing method comprises: placing a substrate to be photoetched into a vacuum chamber of a magnetron sputtering device, and sequentially plating three layers of dielectric films with different target materials and specific sputtering powers and incident angles, that is, the first target material forms a first dielectric film on the substrate at an incident angle of less than or equal to 15°, the second target material is incident perpendicular to the first dielectric film to form a second dielectric film, and the third target material forms a third dielectric film on the second dielectric film at an incident angle of less than or equal to 15°, and then the three layers of dielectric films are photoetched and etched to obtain a grating. The present invention forms a multi-layer structure grating film by plating different atoms at different incident angles during sputtering, effectively reducing film layer voids and unevenness, improving overall density and flatness, increasing the chances of mechanical bite and chemical bonding, enhancing the bonding strength between the layers, and improving the stability and durability of the grating in different environments.

Description

Technical Field

[0001] The present invention relates to the technical field of optical elements, and in particular to a grating manufacturing method and a grating ruler. Background Art

[0002] In the existing grating production, whether a single-layer grating film or a multi-layer grating film is plated on the substrate to be photolithography, the incident angle of the target sputtered atoms is usually always perpendicular to the substrate to be photolithography or one of the grating films. However, this method has many shortcomings.

[0003] In terms of film quality, vertical incidence can easily lead to poor uniformity of the film, and vertical atomic impact can easily cause local accumulation and concentration, affecting the overall uniformity of the film and affecting the optical performance of high-precision optical gratings. At the same time, vertical incidence makes it difficult to effectively fill surface microscopic defects, resulting in increased surface roughness of the film, affecting the scattering of light, and reducing optical quality and signal clarity.

[0004] In terms of film layer bonding strength, vertical incidence results in a single bonding method and insufficient mechanical bonding strength. When faced with temperature changes or mechanical vibrations, the film layer is prone to stratification and peeling, affecting the service life and stability of the grating. In addition, chemical bonding is also limited and a stable interface structure cannot be fully formed, resulting in performance degradation during long-term use. Summary of the invention

[0005] The main purpose of the present invention is to provide a grating production method and a grating ruler, aiming to solve the technical problem that in the existing grating production, the incident angle of the sputtered atoms of the target material is usually always perpendicular to the substrate to be photolithography or one of the grating films, resulting in poor film quality and low film bonding strength.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides a grating manufacturing method, comprising:

[0007] The substrate to be photolithography is placed in a vacuum chamber of a magnetron sputtering device through a fixture, and a preset first target material is sputtered and deposited on the substrate to be photolithography by a first predetermined sputtering power to form a first dielectric film, wherein the incident angle of the sputtered atoms of the first target material on the substrate to be photolithography is less than or equal to 15°;

[0008] sputtering and depositing a preset second target material on the first dielectric film by a second predetermined sputtering power to form a second dielectric film, wherein the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film;

[0009] sputtering and depositing a preset third target material on the second dielectric film by a third predetermined sputtering power to form a third dielectric film, wherein an incident angle of sputtered atoms of the third target material on the second dielectric film is less than or equal to 15°;

[0010] According to a preset grating pattern, the first dielectric film, the second dielectric film and the third dielectric film are photolithographically processed, and then etched to obtain a grating.

[0011] Furthermore, the step before placing the substrate to be photolithographically processed into the vacuum chamber of the magnetron sputtering device through a fixture includes:

[0012] The substrate to be photolithographic is polished with sandpaper whose particle size values ​​increase from a starting particle size value to a final particle size value in sequence, and whose particle size increases in a gradient of one level per 100 meshes, to obtain a polished sample, wherein the sandpaper is inclined at an angle of 10° to 30° with the surface of the substrate to be photolithographic, and the sandpaper rotates clockwise from the center of the surface of the substrate to be photolithographic to the surrounding areas;

[0013] The polished sample is placed in an acetone solution for ultrasonic cleaning for 10-15 minutes to obtain an ultrasonically cleaned sample;

[0014] The ultrasonically cleaned sample is cleaned by using deionized water to rotate counterclockwise from the center of the surface of the substrate to be photoetched to the surrounding areas for 1-2 minutes to obtain a rotationally cleaned sample;

[0015] The spin-cleaned sample is immersed in a dilute hydrochloric acid solution for 5-10 minutes, rinsed again with deionized water and dried to obtain the substrate to be photoetched.

[0016] Furthermore, the step of depositing a preset first target material on the substrate to be photolithographically processed by sputtering at a first predetermined sputtering power to form a first dielectric film, wherein the incident angle of the sputtered atoms of the first target material on the substrate to be photolithographically processed is less than or equal to 15°, comprises:

[0017] The background vacuum degree in the vacuum chamber of the magnetron sputtering device is reduced to less than 5×10 -4 Pa, and introduce argon gas of a predetermined concentration as a sputtering gas to obtain a first vacuum chamber, wherein the gas flow rate of the argon gas is 30-40 sccm;

[0018] In the first vacuum chamber, the sputtering gas causes the sputtering atoms of the first target material to perform parabolic motion and / or inclined zigzag motion according to the first predetermined sputtering power, so that the first target material is sputtered and deposited on the substrate to be photolithography to form a first dielectric film, wherein the incident angle of the sputtering atoms of the first target material is adjusted at a step speed of 1°-2° each time, and the distance between the first target material and the substrate to be photolithography is 2-5 cm;

[0019] Determining whether the film thickness of the first dielectric film is within a range of ±5% of a first preset film thickness;

[0020] If so, stop sputtering the first target material to obtain a first photoresist film sample.

[0021] Furthermore, the step of depositing a preset second target material on the first dielectric film by sputtering at a second predetermined sputtering power to form the second dielectric film by plating, wherein the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film, comprises:

[0022] Cleaning the first photoresist film sample by argon plasma bombardment in a first vacuum chamber, and determining whether the concentration of the sputtering gas in the first vacuum chamber is within a range of ±10 of the predetermined concentration;

[0023] If not, then introduce argon gas again to make the sputtering gas reach a predetermined concentration, and introduce nitrogen gas of a predetermined concentration as a reaction gas to obtain a second vacuum chamber, wherein the gas flow rate of the argon gas is 40-50 sccm, and the gas flow rate of the nitrogen gas is 10-15 sccm;

[0024] In the second vacuum chamber, the sputtering atoms of the second target material are subjected to spiral motion and / or bending motion according to the second predetermined sputtering power by the sputtering gas and the reaction gas, so that the second target material is sputtered and deposited on the first photoresist film sample to form a second dielectric film, wherein the incident angle of the sputtering atoms of the second target material is adjusted at a step speed of 1°-2° each time, and the distance between the second target material and the first photoresist film sample is 5-8 cm;

[0025] Determining whether the film thickness of the second dielectric film is within a range of ±5% of a second preset film thickness;

[0026] If so, stop sputtering the second target material to obtain a second photoresist film sample.

[0027] Further, the step of depositing a preset third target material on the second dielectric film by sputtering at a third predetermined sputtering power to form a third dielectric film by plating, wherein the incident angle of the sputtered atoms of the third target material on the second dielectric film is less than or equal to 15°, comprises:

[0028] Cleaning the second photoresist film sample by oxygen plasma in the second vacuum chamber, and determining whether the concentration of the sputtering gas in the second vacuum chamber is within a range of ±10 of the predetermined concentration;

[0029] If not, then introduce argon gas again to make the sputtering gas reach a predetermined concentration, and introduce oxygen gas with a predetermined concentration as a reaction gas to obtain a third vacuum chamber, wherein the gas flow rate of the argon gas is 30-40 sccm, and the gas flow rate of the oxygen gas is 5-10 sccm;

[0030] In the third vacuum chamber, the sputtering atoms of the third target material are subjected to parabolic motion and / or inclined zigzag motion according to the third predetermined sputtering power by the sputtering gas and the reaction gas, so that the third target material is sputtered and deposited on the second photoresist film sample to form a third dielectric film, wherein the incident angle of the sputtering atoms of the third target material is adjusted at a step speed of 1°-2° each time, and the distance between the third target material and the second photoresist film sample is 6-9 cm;

[0031] Determining whether the film thickness of the third dielectric film is within a range of ±5% of a third preset film thickness;

[0032] If so, stop sputtering the third target material to obtain a third photoresist film sample.

[0033] Furthermore, after the step of depositing the preset third target material on the second dielectric film by sputtering at a third predetermined sputtering power to form the third dielectric film by plating, the method further comprises:

[0034] In a vacuum environment, guiding the evaporated organic material vapor to the surface of the third dielectric film of the third photoresist film sample to form a protective film, wherein a guiding angle between the organic material vapor and the third dielectric film is less than or equal to 15°, and the organic material vapor covers the surface of the third dielectric film from left to right according to a motion trajectory of a first preset sinusoidal curve parameter;

[0035] Determining whether the film thickness of the protective film is within a range of ±5% of a fourth preset film thickness;

[0036] If so, evaporation of the organic material is stopped.

[0037] Furthermore, the step of photolithography the first dielectric film, the second dielectric film and the third dielectric film according to a preset grating pattern, and then etching to obtain a grating comprises:

[0038] Spin coating a preset photoresist on the third dielectric film so that the thickness of the photoresist reaches a fifth preset film thickness to obtain a coated sample;

[0039] A mask with a preset grating pattern is tightly attached to the glue-coated sample, and then exposed to obtain an exposed sample;

[0040] The exposed sample is placed in a developer and stirred by a stirring device to develop the exposed sample to obtain a sample to be etched with a grating pattern after photolithography, wherein the stirring angle between the stirring device and the liquid surface of the developer is 10°-20°, and the stirring device stirs clockwise and counterclockwise for 30 seconds to 60 seconds respectively.

[0041] Furthermore, the step of spin coating a preset photoresist on the third dielectric film so that the thickness of the photoresist reaches a fifth preset film thickness to obtain a coated sample comprises:

[0042] Dropping the photoresist onto the center of the third dielectric film to form a first photoresist, and on an ellipse centered on the first photoresist and with an eccentricity less than or equal to 0.8, dropping the photoresist onto the circumference of the ellipse to form a plurality of second photoresists, to obtain a sample to be rotated, wherein the first photoresist and the second photoresist are symmetrical to each other;

[0043] Rotate the sample to be rotated clockwise at a preset speed;

[0044] Determine whether the film thickness of the first photoresist and the second photoresist on the sample to be rotated is within a range of ±5% of a fifth preset film thickness;

[0045] If so, the rotation of the sample to be rotated is stopped to obtain the glue-coated sample.

[0046] Furthermore, the step of photolithography the first dielectric film, the second dielectric film and the third dielectric film according to a preset grating pattern, and then etching to obtain a grating comprises:

[0047] Putting the sample to be etched into a first dielectric solution, and determining whether the etching depth of the third dielectric film on the sample to be etched reaches a first set depth;

[0048] If yes, the surface of the sample to be etched is rinsed with deionized water in a clockwise direction from the center to the periphery, and then dried to obtain a first etched sample;

[0049] placing the first etching sample into a second dielectric solution, and determining whether the etching depth of the second dielectric film on the first etching sample reaches a second set depth;

[0050] If yes, the surface of the first etched sample is rinsed counterclockwise from the center to the periphery with the deionized water, and then dried to obtain a second etched sample;

[0051] placing the second etching sample into a third medium solution, and determining whether the etching depth of the first medium film on the second etching sample reaches a third set depth;

[0052] If so, the surface of the second etched sample is rinsed from left to right according to a motion trajectory of a second preset sinusoidal curve parameter using the deionized water, and then dried to obtain the grating.

[0053] The present invention further proposes a grating ruler, comprising the grating manufacturing method described in any one of the above embodiments of the claims, wherein the first dielectric film, the second dielectric film and the third dielectric film are sequentially plated on the substrate to be photolithographic from bottom to top.

[0054] Beneficial effects:

[0055] A grating manufacturing method of the present invention comprises: placing a substrate to be photoetched into a vacuum chamber of a magnetron sputtering device through a clamp, allowing a preset first target material to be sputtered and deposited on the substrate to be photoetched by a first predetermined sputtering power, and forming a first dielectric film by plating, wherein the incident angle of the sputtered atoms of the first target material on the substrate to be photoetched is less than or equal to 15°; sputtering a preset second target material on the first dielectric film by a second predetermined sputtering power, and forming a second dielectric film by plating, wherein the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film; sputtering a preset third target material on the second dielectric film by a third predetermined sputtering power, and forming a third dielectric film by plating, wherein the incident angle of the sputtered atoms of the third target material on the second dielectric film is less than or equal to 15°; and photoetching the first dielectric film, the second dielectric film and the third dielectric film according to a preset grating pattern, and then etching to obtain a grating. When the sputtered atoms of the first target are deposited on the substrate to be photolithographic at an incident angle of less than or equal to 15°, the small angle of incidence enables the atoms to be deposited in a relatively "gentle" manner. The atoms have a certain lateral motion component and can spread more fully on the surface of the substrate, thereby effectively filling the tiny pores and unevenness on the surface, making the film layer more dense and uniform, which helps to improve the optical performance of the grating. In addition to the vertical impact force, there is also lateral friction, which is conducive to enhancing the physical adsorption and chemical bonding between the atoms and the substrate, making the film layer and the substrate more firmly combined, and improving the stability and durability of the grating; when the incident angle of the sputtered atoms of the second target is perpendicular to the first dielectric film, the vertical incidence can ensure that the sputtered atoms are evenly deposited on the first dielectric film, making the atoms more regularly stacked in the vertical direction, which is conducive to forming a flat second dielectric film with uniform thickness, ensuring better optical performance, and reducing the optical path caused by uneven film thickness. The problem of difference is solved, the diffraction efficiency and accuracy of the grating are improved, the atoms with vertical incidence can form a tight and orderly combination with the surface of the first dielectric film, and the bonding strength between the second dielectric film and the first dielectric film is enhanced; when the incident angle of the sputtered atoms of the third target on the second dielectric film is less than or equal to 15°, the smaller incident angle makes the sputtered atoms carry a lateral motion component, which helps the atoms to better fill the tiny pits and gaps that may exist on the surface of the second dielectric film during the deposition process, making the structure of the third dielectric film more compact and uniform, which can effectively reduce the scattering and reflection loss of light and improve the optical performance of the grating. The inclined incident angle allows the atoms and the second dielectric film to form a multi-angle interaction. In addition to the vertical bonding force, the lateral force also helps to enhance the mechanical bite force, promote the formation of chemical bonds between atoms and the film layer, make the bonding between the third dielectric film and the second dielectric film more firm, and improve the stability and reliability of the grating.

[0056] Therefore, by coating a multilayer grating film with different incident angles of different atoms, the film growth is more diverse and controllable. For the quality of the film, atoms incident at different angles can fill film defects from different directions, reduce voids and unevenness, improve overall density and flatness, and thus improve optical performance and signal transmission quality. In terms of film bonding, multiple incident angles allow atoms to form a more complex bonding structure with the film or substrate, increasing the chances of mechanical engagement and chemical bonding, enhancing the bonding strength between layers, reducing the risk of delamination and peeling, and improving the stability and durability of the grating in different environments, effectively overcoming the problems of poor film quality and low bonding caused by traditional vertical incident angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A flow chart of a grating manufacturing method according to an embodiment of the present invention;

[0058] Figure 2 A cross-sectional view of a grating ruler according to an embodiment of the present invention.

[0059] in:

[0060] 1. Substrate to be photolithographically processed; 2. First dielectric film; 3. Second dielectric film; 4. Third dielectric film; 5. Protective film.

[0061] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0062] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0063] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0064] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, a direct connection, or an indirect connection 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 invention can be understood according to specific circumstances.

[0065] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0066] Reference Figure 1-Figure 2 This embodiment provides a grating manufacturing method, comprising:

[0067] S1: placing a substrate 1 to be photolithographically processed into a vacuum chamber of a magnetron sputtering device through a fixture, and depositing a preset first target material on the substrate 1 to be photolithographically processed by sputtering at a first predetermined sputtering power to form a first dielectric film 2, wherein the incident angle of the sputtered atoms of the first target material on the substrate 1 to be photolithographically processed is less than or equal to 15°;

[0068] S2: sputtering and depositing a preset second target material on the first dielectric film 2 by a second predetermined sputtering power to form a second dielectric film 3, wherein the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film 2;

[0069] S3: sputtering and depositing a preset third target material on the second dielectric film 3 by a third predetermined sputtering power to form a third dielectric film 4, wherein the incident angle of the sputtered atoms of the third target material on the second dielectric film 3 is less than or equal to 15°;

[0070] S4: according to a preset grating pattern, the first dielectric film 2, the second dielectric film 3 and the third dielectric film 4 are photolithographically processed, and then etched to obtain a grating.

[0071] In the above embodiment, for step S1, the magnetron sputtering device is first prepared, the sealing of the vacuum chamber and the performance of each component are checked, the substrate 1 to be photolithography is fixed with a suitable fixture to ensure that it is stable and does not affect sputtering, the fixture with the substrate is placed in the vacuum chamber, and then the background vacuum of the vacuum chamber is evacuated to less than 5×10⁻ 4 Pa, to reduce the interference of impurities, 30-40sccm of argon is introduced as sputtering gas, then, sputtering is started, the preset first target is at a first predetermined sputtering power, and the sputtered atoms move in a parabolic and / or inclined zigzag shape under the action of argon, and the incident angle of the sputtered atoms is controlled to be less than or equal to 15° by adjusting parameters such as the distance between the target and the substrate (2-5cm), wherein the incident angle of the sputtered atoms does not include 0°, and at the same time, the film thickness is monitored in real time by a film thickness monitoring device, wherein the film thickness monitoring device includes but is not limited to a quartz crystal microbalance, an optical interferometer film thickness measuring instrument, an ellipsometer, etc. When the film thickness is within the range of ±5% of the first preset film thickness, the sputtering is stopped to obtain a first dielectric film 2. When the sputtered atoms of the first target material are deposited on the substrate 1 to be photolithographically processed at an incident angle of less than or equal to 15°, the small angle of incidence enables the atoms to be deposited in a relatively "gentle" manner. The atoms have a certain lateral motion component and can spread more fully on the surface of the substrate 1 to be photolithographically processed, thereby effectively filling the tiny pores and unevenness on the surface, making the film layer more dense and uniform, which helps to improve the optical performance of the grating. In addition to the vertical impact force, there is also lateral friction, which is conducive to enhancing the physical adsorption and chemical bonding between the atoms and the substrate 1 to be photolithographically processed, so that the first dielectric film 2 and the substrate 1 to be photolithographically processed are more firmly combined, and the stability and durability of the grating are improved. This step can make the first dielectric film 2 deposited evenly on the substrate, improve the bonding force between the film layer and the substrate, and the smaller incident angle can fill the microscopic defects of the substrate. The uniform film layer provides a good foundation for subsequent photolithography and etching, which is conducive to the uniform coating of the photoresist and the precise control of the accuracy of the photolithographic pattern, and can also protect the substrate during etching.

[0072] For step S2, first, the sample on which the first dielectric film 2 has been formed is processed, and the first photoresist film sample is cleaned by bombardment with argon plasma, and then it is determined whether the sputtering gas concentration in the first vacuum chamber is within the range of ±10 of the predetermined concentration. If not, argon is introduced again to make it reach the predetermined concentration, and 10-15 sccm nitrogen is introduced as a reaction gas to form a second vacuum chamber. Then, in the second vacuum chamber, the preset second target material is at a second predetermined sputtering power, and the sputtered atoms move toward the first dielectric film 2 in a spiral motion and / or a bending motion under the action of the sputtering gas and the reaction gas. By adjusting relevant parameters, it is ensured that the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film 2, and the distance between the target material and the first photoresist film sample is maintained at 5-8 cm. At the same time, the film thickness of the second dielectric film 3 is monitored in real time. When it is within the range of ±5% of the second preset film thickness, the sputtering is stopped to obtain the second dielectric film 3. When the incident angle of the sputtered atoms of the second target is perpendicular to the first dielectric film 2, the vertical incidence can ensure that the sputtered atoms are uniformly deposited on the first dielectric film 2, so that the atoms are more regularly stacked in the vertical direction, which is conducive to forming a flat second dielectric film 3 with uniform thickness, ensuring better optical performance, reducing problems such as optical path difference caused by uneven film thickness, improving the diffraction efficiency and accuracy of the grating, and enabling the vertically incident atoms to form a tight and orderly bond with the surface of the first dielectric film 2, thereby enhancing the bonding strength between the second dielectric film 3 and the first dielectric film 2. This step can form a uniform second dielectric film 3 on the first dielectric film 2, and the vertical incident angle helps to improve the regularity and quality of the film layer. The multilayer film structure further enhances the support for the photolithography and etching processes, provides a flatter surface for the photoresist, better controls the accuracy of the photolithography pattern, and can better protect the internal structure during etching, thereby improving the quality and reliability of the grating.

[0073] For step S3, firstly, the second photoresist film sample is cleaned with oxygen plasma, and it is determined whether the sputtering gas concentration in the second vacuum chamber is within the range of ±10 of the predetermined concentration. If not, argon gas is introduced again to reach the predetermined concentration, and 5-10 sccm of oxygen is introduced as a reaction gas to form a third vacuum chamber. Then, in the third vacuum chamber, the preset third target material is under a third predetermined sputtering power, and the sputtered atoms move toward the second dielectric film 3 in a parabolic motion and / or an inclined zigzag motion under the action of the sputtering gas and the reaction gas. By adjusting relevant parameters, the incident angle of the sputtered atoms of the third target material on the second dielectric film 3 is less than or equal to 15°, wherein the incident angle of the sputtered atoms does not include 0°, and the distance between the target material and the second photoresist film sample is 6-9 cm. At the same time, the film thickness of the third dielectric film 4 is monitored in real time. When it is within the range of ±5% of the third preset film thickness, the sputtering is stopped to obtain the third dielectric film 4. When the incident angle of the sputtered atoms of the third target on the second dielectric film 3 is less than or equal to 15°, the smaller incident angle makes the sputtered atoms carry a lateral motion component, which helps the atoms to better fill the tiny pits and gaps that may exist on the surface of the second dielectric film 3 during the deposition process, making the structure of the third dielectric film 4 more compact and uniform, which can effectively reduce the scattering and reflection loss of light and improve the optical performance of the grating. The inclined incident angle allows the atoms and the second dielectric film 3 to form a multi-angle interaction. In addition to the vertical bonding force, the lateral force also helps to enhance the mechanical bite force, promote the formation of chemical bonds between atoms and the film layer, make the third dielectric film 4 and the second dielectric film 3 more firmly bonded, and improve the stability and reliability of the grating. This step can form a uniform third dielectric film 4 on the second dielectric film 3. The smaller incident angle is conducive to filling the microscopic defects on the surface of the film layer and enhancing the bonding force between the film layers. The multi-layer film structure provides better conditions for lithography and etching, improves the accuracy of lithography patterns, protects the internal structure, and improves the quality and reliability of the grating.

[0074] For step S4, first, a preset photoresist is spin-coated on the third dielectric film 4, and the photoresist is dripped to the center of the third dielectric film 4 to form a first photoresist. Photoresist is dripped on the circumference of an ellipse with the first photoresist as the center and the eccentricity less than or equal to 0.8 to form multiple second photoresists. The sample to be rotated is rotated clockwise. When the photoresist thickness reaches the fifth preset film thickness, a coated sample is obtained. Then, a mask with a preset grating pattern is tightly attached to the coated sample and exposed to obtain an exposed sample. Then, the exposed sample is placed in a developer, and the stirring angle between the stirring device and the developer liquid surface is 10°-20°. The stirring is performed clockwise and counterclockwise for 30 seconds to 60 seconds respectively, so that the exposed sample is developed to obtain a sample to be etched with a grating pattern after photolithography. Finally, the sample to be etched is placed in the first, second, and third dielectric solutions in turn, and it is judged whether the etching depth of each dielectric film reaches the set depth. When all are satisfied, it is rinsed and dried in a corresponding rotating manner with deionized water to finally obtain a grating. The steps can accurately transfer the preset grating pattern to the dielectric film, the uniform coating and precise control of the photoresist in the photolithography process are helpful to improve the accuracy of the grating pattern, and the etching process can accurately remove the unnecessary parts to obtain the grating that meets the requirements, improve the quality and optical performance of the grating, and meet the needs of practical applications. In addition, the first dielectric film 2, the second dielectric film 3 and the third dielectric film 4 are sequentially plated on the substrate 1 to be photolithography from bottom to top, the first dielectric film 2 is any one of a single chromium film, a single molybdenum film, a single nickel film and a single titanium film, the second dielectric film 3 is any one of a chromium nitride film, a molybdenum nitride film, a nickel nitride film and a titanium nitride film, and the third dielectric film 4 is any one of a chromium oxide film, a molybdenum oxide film, a nickel oxide film and a titanium oxide film.

[0075] In summary, by coating multi-layer grating films with different incident angles of different atoms, the film growth is more diverse and controllable. For the quality of the film, atoms incident at different angles can fill film defects from different directions, reduce voids and unevenness, improve overall density and flatness, and thus improve optical performance and signal transmission quality. In terms of film bonding, multiple incident angles allow atoms to form a more complex bonding structure with the film or substrate, increasing the chances of mechanical engagement and chemical bonding, enhancing the bonding strength between layers, reducing the risk of delamination and peeling, and improving the stability and durability of the grating in different environments, effectively overcoming the problems of poor film quality and low bonding caused by traditional vertical incident angles.

[0076] Reference Figure 1-Figure 2 In one embodiment, the step before placing the substrate 1 to be photolithographically processed into the vacuum chamber of the magnetron sputtering device through a fixture includes:

[0077] The substrate 1 to be photolithographically processed is polished with sandpaper whose particle size values ​​are sequentially increased from a starting particle size value to a final particle size value, and whose particle size increment gradient is one level per 100 meshes, to obtain a polished sample, wherein the sandpaper has an inclination angle of 10°-30° with respect to the surface of the substrate 1 to be photolithographically processed, and the sandpaper rotates clockwise from the center of the surface of the substrate 1 to be photolithographically processed toward the surroundings;

[0078] The polished sample is placed in an acetone solution for ultrasonic cleaning for 10-15 minutes to obtain an ultrasonically cleaned sample;

[0079] The ultrasonically cleaned sample is cleaned by using deionized water in a counterclockwise rotation from the center of the surface of the substrate 1 to be photoetched to the surrounding areas for 1-2 minutes to obtain a rotationally cleaned sample;

[0080] The spin-cleaned sample is immersed in a dilute hydrochloric acid solution for 5-10 minutes, rinsed again with deionized water and dried to obtain the substrate 1 to be photoetched.

[0081] In the above embodiment, sandpaper with a suitable particle size range is first selected, and the starting particle size and the ending particle size are determined according to the material and surface condition of the substrate 1 to be photolithographic. For example, for a substrate with a relatively rough surface, the starting particle size can be selected as 200 mesh and the ending particle size can be selected as 800 mesh. The sandpaper is kept at an inclination angle of 10°-30° with the surface of the substrate 1 to be photolithographic, and is polished clockwise from the center of the surface of the substrate 1 to be photolithographic to the surroundings. During the polishing process, the sandpaper is replaced in an order of increasing particle size by one level every 100 mesh. Such gradual polishing can effectively remove microscopic unevenness and impurities on the surface of the substrate to obtain a polished sample. The polished sample is placed in an acetone solution, which can dissolve some grease and organic impurities. The ultrasonic cleaning equipment is turned on and the cleaning time is set to 10-15 minutes. Ultrasonic vibration can make the acetone solution better contact with the sample surface, enhance the cleaning effect, remove surface dirt, and obtain an ultrasonically cleaned sample.

[0082] Then, the ultrasonically cleaned sample is taken out and placed in deionized water. The deionized water is cleaned counterclockwise from the center of the surface of the substrate 1 to be photolithographic to the surroundings. The cleaning time is 1-2 minutes. This rotation cleaning method can further remove the residual acetone and other impurities on the surface of the sample to obtain a rotation cleaned sample. The rotation cleaned sample is placed in a dilute hydrochloric acid solution and soaked for 5-10 minutes. The dilute hydrochloric acid can remove some impurities such as metal oxides on the surface of the sample. After the soaking is completed, the sample is rinsed with deionized water again to remove the residual dilute hydrochloric acid. Finally, the sample is placed in a drying device for drying to obtain the treated substrate 1 to be photolithographic. This pretreatment step can effectively clean the surface of the substrate 1 to be photolithographic, remove impurities and microscopic unevenness, make the dielectric film formed by subsequent magnetron sputtering more uniform, improve the adhesion between the film layer and the substrate, and also facilitate the photolithography and etching processes, and improve the quality and accuracy of the grating.

[0083] Reference Figure 1-Figure 2 In one embodiment, the step of depositing a preset first target material on the substrate 1 to be photolithographically processed by sputtering at a first predetermined sputtering power to form a first dielectric film 2, wherein the incident angle of the sputtered atoms of the first target material on the substrate 1 to be photolithographically processed is less than or equal to 15°, comprises:

[0084] The background vacuum degree in the vacuum chamber of the magnetron sputtering device is evacuated to less than 5×10-4Pa, and argon gas of a predetermined concentration is introduced as a sputtering gas to obtain a first vacuum chamber, wherein the gas flow rate of the argon gas is 30-40sccm;

[0085] In the first vacuum chamber, the sputtering atoms of the first target material are subjected to parabolic motion and / or inclined zigzag motion according to the first predetermined sputtering power by the sputtering gas, so that the first target material is sputtered and deposited on the substrate 1 to be photolithography to form a first dielectric film 2, wherein the incident angle of the sputtering atoms of the first target material is adjusted at a step speed of 1°-2° each time, and the distance between the first target material and the substrate 1 to be photolithography is 2-5 cm;

[0086] Determining whether the film thickness of the first dielectric film 2 is within a range of ±5% of a first preset film thickness;

[0087] If so, stop sputtering the first target material to obtain a first photoresist film sample.

[0088] In the above embodiment, the substrate 1 to be photolithographically processed is first placed in the vacuum chamber of the magnetron sputtering device, and then the vacuum pump is started to evacuate the chamber. The background vacuum degree needs to be evacuated to less than 5×10⁻ 4Pa, this is to reduce the impurity gas in the chamber and create a pure sputtering environment. After reaching the required vacuum degree, argon gas is introduced as sputtering gas according to the predetermined concentration, and the argon gas flow rate is controlled at 30-40sccm. Here, it is assumed that the predetermined concentration of argon gas is 50% (volume fraction). At this time, the first vacuum chamber is formed. When the first target material is chromium (Cr), the first predetermined sputtering power is set to 200 watts. In the first vacuum chamber, the sputtering power supply is turned on to make the chromium target material start sputtering at a power of 200 watts. Under the action of argon gas, the sputtered atoms move toward the substrate 1 to be photolithographically processed in a parabolic motion and / or an inclined zigzag motion. In this process, it is necessary to accurately control the incident angle of the sputtered atoms of the chromium target material on the substrate 1 to be photolithographic processed. By adjusting the relevant parameters of the sputtering device, such as changing the distance between the target material and the substrate and adjusting the motion trajectory control device of the sputtered atoms, the incident angle is adjusted at a step speed of 1°-2° each time, and it is ensured that the target material and the substrate to be photolithographic are close to each other. The distance between the target and the substrate 1 is between 2-5 cm, so that the sputtered atoms can be deposited on the substrate at a smaller angle, which is beneficial to filling the micro defects on the surface of the substrate and improving the quality of the film layer. Assuming that the first preset film thickness is 100 nanometers, during the sputtering process, the film thickness monitoring device is used to monitor the film thickness of the first dielectric film 2 in real time. According to the preset first preset film thickness of 100 nanometers, it is judged whether the current film thickness is within the range of ±5%, that is, whether the film thickness is between 95 nanometers and 105 nanometers. If the film thickness has not yet reached the requirement, the sputtering process continues; if the film thickness meets the requirement, the sputtering of the first target material is stopped immediately to obtain a first photolithography film sample. This step can form a uniform first dielectric film 2 on the substrate 1 to be photolithographically processed. Selecting chromium as the target material ensures the chemical stability and good adhesion of the film layer. The precisely controlled sputtering conditions ensure the quality of the film layer. The smaller incident angle fills the micro defects and improves the adhesion. The appropriate film thickness ensures the accuracy of the subsequent process and provides a good foundation for photolithography and etching.

[0089] Reference Figure 1-Figure 2 In one embodiment, the step of depositing a preset second target material on the first dielectric film 2 by sputtering at a second predetermined sputtering power to form a second dielectric film 3 by plating, wherein the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film 2, comprises:

[0090] Cleaning the first photoresist film sample by argon plasma bombardment in a first vacuum chamber, and determining whether the concentration of the sputtering gas in the first vacuum chamber is within a range of ±10 of the predetermined concentration;

[0091] If not, then introduce argon gas again to make the sputtering gas reach a predetermined concentration, and introduce nitrogen gas of a predetermined concentration as a reaction gas to obtain a second vacuum chamber, wherein the gas flow rate of the argon gas is 40-50 sccm, and the gas flow rate of the nitrogen gas is 10-15 sccm;

[0092] In the second vacuum chamber, the sputtering atoms of the second target material are subjected to spiral motion and / or bending motion according to the second predetermined sputtering power by the sputtering gas and the reaction gas, so that the second target material is sputtered and deposited on the first photoresist film sample to form a second dielectric film 3, wherein the incident angle of the sputtering atoms of the second target material is adjusted at a step speed of 1°-2° each time, and the distance between the second target material and the first photoresist film sample is 5-8 cm;

[0093] Determine whether the film thickness of the second dielectric film 3 is within a range of ±5% of a second preset film thickness;

[0094] If so, stop sputtering the second target material to obtain a second photoresist film sample.

[0095] In the above embodiment, in the first vacuum chamber, the first photoresist film sample is first bombarded and cleaned by using argon plasma. The purpose of this step is to remove impurities that may exist on the surface of the first photoresist film sample and make the surface cleaner for the subsequent deposition of the second dielectric film 3. Then, it is necessary to determine whether the concentration of argon in the first vacuum chamber is within the range of ±10 of the predetermined concentration (50%), that is, to determine whether the concentration of argon is between 45% and 55%. If the concentration of argon is not within the above range, argon needs to be introduced again to reach the predetermined concentration (50%). At the same time, nitrogen of a predetermined concentration is introduced as a reaction gas. Assuming that the predetermined concentration of nitrogen is 20% (volume fraction), the nitrogen flow rate is controlled at 12 sccm (within the range of 10-15 sccm), and the argon flow rate is adjusted to 46 sccm (within the range of 40-50 sccm), thereby forming a second vacuum chamber.

[0096] When the second target material is chromium nitride (CrN), the second predetermined sputtering power is set to 300 watts. In the second vacuum chamber, under the action of argon and nitrogen, the sputtered atoms of the chromium nitride target material move toward the first photoresist film sample in a spiral motion and / or a bending motion. In this process, the incident angle of the sputtered atoms of the chromium nitride target material must be precisely controlled to be perpendicular to the first dielectric film 2 (chromium film). By adjusting relevant parameters, such as adjusting the distance between the target material and the first photoresist film sample and the motion trajectory control device of the sputtered atoms, the incident angle is adjusted by a step speed of 1°-2° each time. Adjust, and keep the distance between the target and the first photolithography film sample at 6cm (within the range of 5-8cm). Assuming that the second preset film thickness is 150 nanometers, during the sputtering process, use the film thickness monitoring device to monitor the film thickness of the second dielectric film 3 in real time. According to the pre-set second preset film thickness of 150 nanometers, judge whether the current film thickness is within the range of ±5%, that is, judge whether the film thickness is between 142.5 nanometers and 157.5 nanometers. If the film thickness is not within this range, the sputtering process continues; if the film thickness is within this range, stop sputtering the second target material, and obtain the second photolithography film sample. This step can form a uniform second dielectric film 3 on the first dielectric film 2. The vertical incident angle and the appropriate film thickness ensure the quality of the film layer, providing a good foundation for subsequent processes. The multi-layer film structure enhances the support for photolithography and etching, which is conducive to improving the quality and accuracy of the grating.

[0097] Reference Figure 1-Figure 2 In one embodiment, the step of depositing a preset third target material on the second dielectric film 3 by sputtering at a third predetermined sputtering power to form a third dielectric film 4, wherein the incident angle of the sputtered atoms of the third target material on the second dielectric film 3 is less than or equal to 15°, comprises:

[0098] Cleaning the second photoresist film sample by oxygen plasma in the second vacuum chamber, and determining whether the concentration of the sputtering gas in the second vacuum chamber is within a range of ±10 of the predetermined concentration;

[0099] If not, then introduce argon gas again to make the sputtering gas reach a predetermined concentration, and introduce oxygen gas with a predetermined concentration as a reaction gas to obtain a third vacuum chamber, wherein the gas flow rate of the argon gas is 30-40 sccm, and the gas flow rate of the oxygen gas is 5-10 sccm;

[0100] In the third vacuum chamber, the sputtering atoms of the third target material are subjected to parabolic motion and / or inclined zigzag motion according to the third predetermined sputtering power by the sputtering gas and the reaction gas, so that the third target material is sputtered and deposited on the second photoresist film sample to form a third dielectric film 4, wherein the incident angle of the sputtering atoms of the third target material is adjusted at a step speed of 1°-2° each time, and the distance between the third target material and the second photoresist film sample is 6-9 cm;

[0101] Determining whether the film thickness of the third dielectric film 4 is within a range of ±5% of a third preset film thickness;

[0102] If so, stop sputtering the third target material to obtain a third photoresist film sample.

[0103] In the above embodiment, in the second vacuum chamber, the second photoresist film sample is first cleaned using oxygen plasma to remove impurities that may exist on the surface of the second photoresist film sample and make the surface cleaner for the subsequent deposition of the third dielectric film 4. Then, it is determined whether the concentration of argon gas in the second vacuum chamber is within the range of ±10 of the predetermined concentration (50%), that is, whether the concentration of argon gas is between 45% and 55%. If the concentration of argon gas is not within the above range, argon gas is introduced again to reach the predetermined concentration (50%), and oxygen gas of a predetermined concentration is introduced as a reaction gas at the same time. Assuming that the predetermined concentration of oxygen is 30% (volume fraction), the oxygen flow rate is controlled at 8 sccm (within the range of 5-10 sccm), and the argon flow rate is adjusted to 35 sccm (within the range of 30-40 sccm), thereby forming the third vacuum chamber.

[0104] When the third target is chromium oxide (Cr 2 O 3), the third predetermined sputtering power is set to 250 W. In the third vacuum chamber, under the action of argon and oxygen, the sputtered atoms of the chromium oxide target move toward the second photoresist film sample in a parabolic motion and / or an inclined zigzag motion. In this process, the incident angle of the sputtered atoms of the chromium oxide target must be precisely controlled to be less than or equal to 15°. By adjusting relevant parameters, such as adjusting the distance between the target and the second photoresist film sample and the motion trajectory control device of the sputtered atoms, the incident angle is adjusted by a step speed of 1°-2° each time, and the distance between the target and the second photoresist film sample is kept at 7cm (within the range of 6-9cm). Assuming that the third preset film thickness is 200 nanometers, during the sputtering process, the film thickness monitoring device is used to monitor the film thickness of the third dielectric film 4 in real time. According to the pre-set third preset film thickness of 200 nanometers, it is judged whether the current film thickness is within the range of ±5%, that is, whether the film thickness is between 190 nanometers and 210 nanometers. If the film thickness is not within this range, the sputtering process continues; if the film thickness is within this range, the sputtering of the third target is stopped, thereby obtaining the third photoresist film sample. This step can form a uniform third dielectric film 4 on the second dielectric film 3. The appropriate incident angle and film thickness ensure the film layer quality. The multilayer film structure is conducive to improving the accuracy of the photolithography pattern, protecting the internal structure, and improving the grating quality and reliability.

[0105] Reference Figure 1-Figure 2 In one embodiment, after the step of depositing the preset third target material on the second dielectric film 3 by sputtering at a third predetermined sputtering power to form the third dielectric film 4 by plating, the method further comprises:

[0106] In a vacuum environment, the evaporated organic material vapor is guided to the surface of the third dielectric film 4 of the third photoresist film sample to form a protective film 5, wherein the guiding angle between the organic material vapor and the third dielectric film 4 is less than or equal to 15°, and the organic material vapor covers the surface of the third dielectric film 4 from left to right according to a motion trajectory of a first preset sinusoidal curve parameter;

[0107] Determining whether the film thickness of the protective film 5 is within a range of ±5% of a fourth preset film thickness;

[0108] If so, evaporation of the organic material is stopped.

[0109] In the above embodiment, in a vacuum environment, firstly, a suitable organic material is selected for evaporation. Here, it is assumed that polyurethane is selected as the organic material. The polyurethane material is heated and evaporated to generate steam. Then, the evaporated organic material steam is guided to the surface of the third dielectric film 4 of the third photoresist film sample by a specific device. During the guiding process, the guiding angle between the organic material steam and the third dielectric film 4 must be strictly controlled to be less than or equal to 15°. For example, this can be achieved by adjusting the direction and angle of the steam outlet. At the same time, it is necessary to ensure that the organic material steam moves from left to right on the surface of the third dielectric film 4 according to the motion trajectory of the first preset sinusoidal curve parameter. The traces are covered, which may require the design of a special steam guiding path and control device to achieve a precise covering method. Assuming that the fourth preset film thickness is 50 nanometers, in the process of the organic material vapor covering the surface of the third dielectric film 4, the film thickness monitoring device is used to monitor the film thickness of the protective film 5 in real time. According to the preset fourth preset film thickness of 50 nanometers, it is judged whether the current film thickness is within the range of ±5%, that is, whether the film thickness is between 47.5 nanometers and 52.5 nanometers. If the film thickness is not within this range, continue to evaporate the organic material; if the film thickness is within this range, stop evaporating the organic material, thereby obtaining the protective film 5 on the substrate 1 to be photoetched. The protective film 5 formed in this step can protect the internal film layer and structure. The selection of organic materials provides a variety of performance advantages. The appropriate covering method and film thickness ensure a good protection effect, which is conducive to improving the stability and service life of the grating and reducing the influence of external factors on the grating.

[0110] Reference Figure 1-Figure 2 In one embodiment, the step of photolithography the first dielectric film 2, the second dielectric film 3 and the third dielectric film 4 according to a preset grating pattern and then etching to obtain a grating comprises:

[0111] Spin coating a preset photoresist on the third dielectric film 4 so that the thickness of the photoresist reaches a fifth preset film thickness to obtain a coated sample;

[0112] A mask with a preset grating pattern is tightly attached to the glue-coated sample, and then exposed to obtain an exposed sample;

[0113] The exposed sample is placed in a developer and stirred by a stirring device to develop the exposed sample to obtain a sample to be etched with a grating pattern after photolithography, wherein the stirring angle between the stirring device and the liquid surface of the developer is 10°-20°, and the stirring device stirs clockwise and counterclockwise for 30 seconds to 60 seconds respectively.

[0114] In the above embodiment, firstly, a suitable photoresist, such as a positive photoresist, is selected, and the photoresist is dripped on the third dielectric film 4 (when a protective film 5 is formed on the third dielectric film 4, the photoresist is dripped on the protective film 5), first dripped to the center to form a first photoresist, and then, on an ellipse with an eccentricity of less than or equal to 0.8 and centered on the first photoresist, the photoresist is dripped on the circumference of the ellipse to form a plurality of second photoresists, to obtain a sample to be rotated, assuming that the amount of the first photoresist dripped is 0.3 ml, and the amount of each second photoresist dripped is about 0.05 ml (estimated based on the area of ​​the third dielectric film 4), the sample to be rotated is rotated clockwise at a speed of 600 rpm, and the film thickness is monitored at the same time. Assuming that the fifth preset film thickness is 1.2 microns, when the film thickness of the first photoresist and the second photoresist is within the range of 1.14-1.26 microns, the rotation is stopped to obtain a coated sample.

[0115] Then, the mask with the preset grating pattern is closely attached to the coated sample. The mask here is specially made according to the required grating pattern. For example, if the grating to be made is a linear grating for spectral analysis, the pattern on the mask is the corresponding linear stripe. The bonding process must ensure that there are no bubbles and gaps to ensure the accuracy of exposure. Then, the exposure operation is carried out. The exposure time and intensity are determined according to factors such as the characteristics of the photoresist and the complexity of the mask pattern. Through exposure, the photoresist undergoes chemical changes in the area corresponding to the mask pattern to obtain an exposed sample. The exposed sample is then exposed. The photo sample is placed in the developer, and the developer should be selected to match the photoresist. For example, if it is a positive photoresist, the corresponding positive developer should be selected, and a stirring device should be used for stirring. The stirring angle between the stirring device and the liquid surface of the developer is 15° (within the range of 10°-20°), and the stirring device stirs clockwise and counterclockwise for 45 seconds (within the range of 30 seconds-60 seconds). Through stirring, the exposed sample is developed, the photoresist in the unexposed area is dissolved, and the photoresist in the exposed area is retained, and the sample to be etched with a grating pattern after photolithography is obtained. This step can accurately transfer the preset grating pattern to the dielectric film. The uniform coating and precise control of the photoresist help to improve the accuracy of the grating pattern. The reasonable operation of the development process ensures the clarity of the pattern and lays the foundation for obtaining high-quality gratings in subsequent etching.

[0116] Reference Figure 1-Figure 2 In one embodiment, the step of spin coating a preset photoresist on the third dielectric film 4 so that the thickness of the photoresist reaches a fifth preset film thickness to obtain a coated sample includes:

[0117] Dropping the photoresist onto the center of the third dielectric film 4 to form a first photoresist, and on an ellipse centered on the first photoresist and with an eccentricity less than or equal to 0.8, dropping the photoresist onto the circumference of the ellipse to form a plurality of second photoresists, to obtain a sample to be rotated, wherein the first photoresist and the second photoresist are symmetrical to each other;

[0118] Rotate the sample to be rotated clockwise at a preset speed;

[0119] Determine whether the film thickness of the first photoresist and the second photoresist on the sample to be rotated is within a range of ±5% of a fifth preset film thickness;

[0120] If so, the rotation of the sample to be rotated is stopped to obtain the glue-coated sample.

[0121] In the above embodiment, a micro-syringe is first used to slowly and accurately drop the photoresist to the center of the third dielectric film 4 to form a first photoresist. The amount of the drop is preliminarily estimated based on the area of ​​the third dielectric film 4 and the thickness of the photoresist required in the end. Here, it is assumed that the area of ​​the third dielectric film 4 is 10 square centimeters, and the amount of the first photoresist is preliminarily estimated to be 0.2 milliliters. Then, with the first photoresist as the center, the photoresist is evenly dropped on the circumference of the ellipse according to the requirement that the eccentricity is less than or equal to 0.8 to form a plurality of second photoresists. In order to ensure uniformity, the dropping speed and position interval are controlled during the dropping process. Here, it is assumed that the amount of each second photoresist is about 0.03 milliliters. A total of 10 second photoresists are dropped on the circumference of the ellipse (determined according to the circumference of the ellipse and the uniformity of the photoresist distribution), and thus a sample to be rotated is obtained.

[0122] The sample to be rotated is placed on a special rotary coating device, which can accurately control the rotation speed. According to past experience and the characteristics of the photoresist, the preset speed is set to 500 rpm, and the rotating device is started to rotate the sample to be rotated in a clockwise direction. During the rotation process, due to the effect of centrifugal force, the photoresist will gradually diffuse to the surroundings, so that the photoresist is more evenly distributed on the third dielectric film 4. During the rotation process, a high-precision film thickness monitoring device is used to monitor the film thickness of the first photoresist and the second photoresist on the sample to be rotated in real time. Assuming that the fifth preset film thickness is 1 micron, it is determined whether the film thickness is within its ±5% range, that is, whether the film thickness is between 0.95 microns and 1.05 microns. If the film thickness does not meet the requirements, the rotation continues; if the film thickness meets the requirements, the rotation of the sample to be rotated is stopped immediately to obtain a coated sample. This step ensures that the photoresist is evenly distributed on the third dielectric film 4 and the thickness meets the requirements through a unique photoresist dripping and rotation method, which provides a good foundation for the exposure and development operations in the subsequent photolithography process, and is beneficial to improving the accuracy and quality of the grating pattern, thereby improving the performance of the entire grating.

[0123] Reference Figure 1-Figure 2 In one embodiment, the step of photolithography the first dielectric film 2, the second dielectric film 3 and the third dielectric film 4 according to a preset grating pattern and then etching to obtain a grating comprises:

[0124] Putting the sample to be etched into a first dielectric solution, and determining whether the etching depth of the third dielectric film 4 on the sample to be etched reaches a first set depth;

[0125] If yes, the surface of the sample to be etched is rinsed with deionized water in a clockwise direction from the center to the periphery, and then dried to obtain a first etched sample;

[0126] Putting the first etching sample into a second dielectric solution, and determining whether the etching depth of the second dielectric film 3 on the first etching sample reaches a second set depth;

[0127] If yes, the surface of the first etched sample is rinsed counterclockwise from the center to the periphery with the deionized water, and then dried to obtain a second etched sample;

[0128] placing the second etching sample into a third medium solution, and determining whether the etching depth of the first medium film 2 on the second etching sample reaches a third set depth;

[0129] If so, the surface of the second etched sample is rinsed from left to right according to a motion trajectory of a second preset sinusoidal curve parameter using the deionized water, and then dried to obtain the grating.

[0130] In the above embodiment, the sample to be etched is placed in the first medium solution. It is assumed here that the first medium solution is an acidic solution specially used for etching chromium oxide. During the etching process, the etching depth of the third medium film 4 should be closely followed. By using a depth monitoring instrument, it is determined whether the etching depth of the third medium film 4 on the sample to be etched reaches the first set depth, wherein the first set depth is less than or equal to the first preset film thickness, assuming that the first set depth is 80 nanometers. If the etching depth does not reach the requirement, continue to etch in the first medium solution; if the etching depth reaches the requirement, the surface of the sample to be etched is rinsed clockwise from the center to the surroundings with deionized water, because this rotating rinsing method can more effectively remove impurities and residual etching solution generated during the etching process. After rinsing, the sample is dried to obtain the first etched sample.

[0131] The first etching sample is placed in the second dielectric solution. It is assumed that the second dielectric solution is an alkaline solution suitable for etching chromium nitride. Similarly, a depth monitoring instrument is used to determine whether the etching depth of the second dielectric film 3 on the first etching sample reaches a second set depth, wherein the second set depth is less than or equal to the second preset film thickness. It is assumed that the first set depth is 110 nanometers and the second set depth is 8 microns. If the etching depth reaches the requirement, the surface of the first etching sample is rinsed counterclockwise from the center to the surroundings with deionized water, and then dried to obtain the second etching sample. This counterclockwise rotation rinsing method is designed for cleaning the second dielectric film 3 after etching, which helps to completely remove impurities generated by etching.

[0132] The second etching sample is placed in the third dielectric solution. Assuming that the third dielectric solution is a mixed solution that can etch elemental chromium, the depth monitoring instrument is used again to determine whether the etching depth of the first dielectric film 2 on the second etching sample reaches the third set depth, wherein the third set depth is less than or equal to the third preset film thickness, assuming that the third set depth is 160 nanometers. If the etching depth reaches the requirement, the surface of the second etching sample is rinsed from left to right according to the motion trajectory of the second preset sinusoidal curve parameter by deionized water, and then dried to obtain a grating. This special rinsing trajectory is to better remove impurities after etching the first dielectric film 2, while ensuring the final quality of the grating. This step can accurately form the required grating structure by precisely controlling the etching depth and a reasonable rinsing method. The effective control of the etching process improves the accuracy and quality of the grating. The rinsing method helps to remove impurities and ensure the grating performance.

[0133] Reference Figure 2 The present invention further proposes a grating ruler, including the grating manufacturing method described in any one of the above embodiments of the claims, wherein the first dielectric film 2, the second dielectric film 3 and the third dielectric film 4 are sequentially plated on the substrate 1 to be photolithographically formed from bottom to top.

[0134] In the above embodiment, the grating ruler is manufactured according to the specific steps of the grating production method described above, wherein the first dielectric film 2, the second dielectric film 3 and the third dielectric film 4 are sequentially plated on the substrate 1 to be photolithographically processed from bottom to top, so that in the interference and diffraction process of light, the uniform film layer can ensure that the light is propagated and interfered in a predetermined manner, thereby improving the measurement accuracy, and the high-precision lithography and etching process ensures the accuracy of key parameters such as the grating pitch of the grating ruler, thereby improving the measurement accuracy. At the same time, the grating ruler can meet the application scenarios that require high-precision measurement, such as measurement tasks in the fields of precision machining and semiconductor manufacturing. The multi-layer film structure can better resist the influence of external factors and reduce the deformation, oxidation or corrosion of the film layer, thereby ensuring the long-term stability of the performance of the grating ruler.

[0135] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A grating manufacturing method, characterized in that: include: The substrate to be photolithography is placed in a vacuum chamber of a magnetron sputtering device through a fixture, and a preset first target material is sputtered and deposited on the substrate to be photolithography by a first predetermined sputtering power to form a first dielectric film, wherein the incident angle of the sputtered atoms of the first target material on the substrate to be photolithography is less than or equal to 15°; sputtering and depositing a preset second target material on the first dielectric film by a second predetermined sputtering power to form a second dielectric film, wherein the incident angle of the sputtered atoms of the second target material is perpendicular to the first dielectric film; sputtering and depositing a preset third target material on the second dielectric film by a third predetermined sputtering power to form a third dielectric film, wherein an incident angle of sputtered atoms of the third target material on the second dielectric film is less than or equal to 15°; According to a preset grating pattern, the first dielectric film, the second dielectric film and the third dielectric film are photolithographically processed, and then etched to obtain a grating; The step of photolithography the first dielectric film, the second dielectric film and the third dielectric film according to the preset grating pattern comprises: Spin coating a preset photoresist on the third dielectric film so that the thickness of the photoresist reaches a fifth preset film thickness to obtain a coated sample; The step of spin coating a preset photoresist on the third dielectric film comprises: The photoresist is dripped onto the center of the third dielectric film to form a first photoresist, and on an ellipse centered on the first photoresist and with an eccentricity less than or equal to 0.8, the photoresist is dripped onto the circumference of the ellipse to form multiple second photoresists, to obtain a sample to be rotated, wherein the first photoresist and the second photoresist are symmetrical to each other.

2. The grating manufacturing method according to claim 1, characterized in that: Before the step of placing the substrate to be photolithographically processed into the vacuum chamber of the magnetron sputtering device through a fixture, the method includes: The substrate to be photolithographic is polished with sandpaper whose particle size values ​​increase from a starting particle size value to a final particle size value in sequence, and whose particle size increases in a gradient of one level per 100 meshes, to obtain a polished sample, wherein the sandpaper is inclined at an angle of 10° to 30° with the surface of the substrate to be photolithographic, and the sandpaper rotates clockwise from the center of the surface of the substrate to be photolithographic to the surrounding areas; The polished sample is placed in an acetone solution for ultrasonic cleaning for 10-15 minutes to obtain an ultrasonically cleaned sample; The ultrasonically cleaned sample is cleaned by using deionized water to rotate counterclockwise from the center of the surface of the substrate to be photoetched to the surrounding areas for 1-2 minutes to obtain a rotationally cleaned sample; The spin-cleaned sample is immersed in a dilute hydrochloric acid solution for 5-10 minutes, rinsed again with deionized water and dried to obtain the substrate to be photoetched.

3. The grating manufacturing method according to claim 1, characterized in that: The step of photolithography the first dielectric film, the second dielectric film and the third dielectric film according to the preset grating pattern and then etching to obtain the grating further includes: A mask with a preset grating pattern is tightly attached to the glue-coated sample, and then exposed to obtain an exposed sample; The exposed sample is placed in a developer and stirred by a stirring device to develop the exposed sample to obtain a sample to be etched with a grating pattern after photolithography, wherein the stirring angle between the stirring device and the liquid surface of the developer is 10°-20°, and the stirring device stirs clockwise and counterclockwise for 30 seconds to 60 seconds respectively.

4. The grating manufacturing method according to claim 3, characterized in that: The step of spin coating a preset photoresist on the third dielectric film so that the thickness of the photoresist reaches a fifth preset film thickness to obtain a coated sample also includes: Rotate the sample to be rotated clockwise at a preset speed; Determine whether the film thickness of the first photoresist and the second photoresist on the sample to be rotated is within a range of ±5% of a fifth preset film thickness; If so, the rotation of the sample to be rotated is stopped to obtain the glue-coated sample.

5. The grating manufacturing method according to claim 3, characterized in that: The step of photolithography the first dielectric film, the second dielectric film and the third dielectric film according to the preset grating pattern and then etching to obtain the grating further includes: Putting the sample to be etched into a first dielectric solution, and determining whether the etching depth of the third dielectric film on the sample to be etched reaches a first set depth; If yes, the surface of the sample to be etched is rinsed with deionized water in a clockwise direction from the center to the periphery, and then dried to obtain a first etched sample; placing the first etching sample into a second dielectric solution, and determining whether the etching depth of the second dielectric film on the first etching sample reaches a second set depth; If yes, the surface of the first etched sample is rinsed counterclockwise from the center to the periphery with the deionized water, and then dried to obtain a second etched sample; placing the second etching sample into a third medium solution, and determining whether the etching depth of the first medium film on the second etching sample reaches a third set depth; If so, the surface of the second etched sample is rinsed from left to right according to a motion trajectory of a second preset sinusoidal curve parameter using the deionized water, and then dried to obtain the grating.

6. A grating ruler, characterized in that: The grating comprises a grating prepared by the grating preparation method according to any one of claims 1 to 5.

Images