An internal tilting grating for optical glasses and its manufacturing method

Abstract

This application discloses a tilted grating inside optical glasses and its manufacturing method. The method includes forming multiple unidirectionally tilted imprinted patterns on a silicon carbide substrate; performing a first treatment on the surface of the imprinted patterns to reduce surface roughness; forming unidirectionally tilted metal patterns in the gaps between adjacent imprinted patterns; removing the imprinted patterns; using the metal patterns as a mask, etching the exposed surface of the silicon carbide substrate along its tilt direction to form a unidirectionally tilted first grating on the silicon carbide substrate; removing the remaining metal patterns; performing a second treatment on the surface of the first grating to reduce surface roughness; performing a third treatment on the surface of the first grating to remove the enriched layer; and removing the top of the first grating to form a second grating. This application enables an overall tilted grating structure, reduces sidewall roughness, thereby enhancing optical performance, improving diffraction efficiency, and increasing long-term stability.

Description

Technical Field

[0001] This application relates to the field of precision manufacturing technology for semiconductor optical devices, and in particular to a tilted grating inside optical glasses and a method for manufacturing the same. Background Technology

[0002] Currently, when using conventional processes to fabricate silicon carbide (SiC) tilted gratings for optical glasses, the resulting tilted gratings often exhibit a pitted and uneven surface with noticeable undulations. This is primarily due to the following factors:

[0003] (1) The mask itself has a high sidewall roughness. During the pattern transfer process during etching, the roughness of the mask sidewall will be transferred to the sidewall of the tilted grating, resulting in roughness of the sidewall surface of the tilted grating.

[0004] (2) When silicon carbide is etched in an inclined direction using a vertical mask and ion beam etching process, a lot of residue will be generated when the mask is consumed, which makes the sidewall of the formed trench (i.e. the sidewall of the inclined grating) curved and rough.

[0005] The high roughness of the sidewalls of the tilted grating will lead to large light scattering loss and reduced diffraction efficiency, thus affecting device performance.

[0006] Furthermore, the traditional method of treating the sidewall surface with high-temperature annealing (above 500℃) to reduce sidewall roughness easily causes thermal damage (surface Si loss) and new defects (Si / C ratio imbalance) on the silicon carbide surface, which can compromise the precision of optical components. Therefore, it is necessary to study a new method for manufacturing tilted gratings inside optical glasses to enhance optical performance, improve diffraction efficiency, and enhance long-term stability. Summary of the Invention

[0007] The purpose of this application is to overcome the above-mentioned problems existing in the prior art and provide an internal tilted grating for optical glasses and a method for manufacturing the same, so as to improve the overall etching morphology of the grating and improve the sidewall roughness, thereby enhancing optical performance, improving diffraction efficiency and long-term stability.

[0008] To achieve the above objectives, the technical solution of this application is as follows:

[0009] According to a first aspect of this application, an embodiment of this application provides a method for manufacturing an internal tilted grating of optical glasses, comprising the following steps:

[0010] Provide silicon carbide substrates;

[0011] Multiple imprinted adhesive patterns that are tilted in the same direction are formed on the surface of the silicon carbide substrate;

[0012] The surface of the embossed pattern is subjected to a first treatment to reduce surface roughness;

[0013] The gap between any two adjacent embossed patterns is filled with metal, and excess metal material on the surface of the embossed patterns is removed to form metal patterns that are inclined in the same direction in the gap, and then the embossed patterns are removed.

[0014] Using the metal pattern as a mask, the exposed surface of the silicon carbide substrate is etched along its tilt direction to form a first grating tilted in the same direction on the silicon carbide substrate, and then the remaining metal pattern is removed.

[0015] The surface of the first grating is subjected to a second treatment to reduce surface roughness;

[0016] The surface of the first grating is subjected to a third processing to remove the enriched layer on the surface;

[0017] A sacrificial layer is applied to the surface of the silicon carbide substrate, exposing the top of the first grating;

[0018] Remove the exposed top of the first grating to form a second grating;

[0019] Remove the sacrificial layer.

[0020] In some embodiments, forming a plurality of unidirectionally tilted imprinted patterns on the surface of the silicon carbide substrate specifically includes:

[0021] A spin-coating adhesive layer is applied to the surface of the silicon carbide substrate;

[0022] A template with a grating pattern having a preset tilt direction is aligned and pressed with the surface of the imprinting adhesive layer, and an imprinting process is used to copy the grating pattern with the preset tilt direction on the template onto the imprinting adhesive layer. After demolding, multiple imprinting adhesive patterns tilted in the same direction are formed on the surface of the silicon carbide substrate.

[0023] In some embodiments, the first treatment of the surface of the imprinted adhesive pattern specifically includes:

[0024] A dry etching process is used, and the first treatment is performed on the sidewall surface of the imprinted adhesive pattern along the tilt direction of the imprinted adhesive pattern to reduce the surface roughness of the sidewall of the imprinted adhesive pattern. The process gas includes O2, the temperature is 60℃~100℃, the pressure is 5mTorr~50mTorr, the source power is 500W~1000W, and the bias power is 50W~200W.

[0025] In some embodiments, the step of filling the gap between any two adjacent embossed patterns with metal, removing excess metal material from the surface of the embossed patterns, forming a metal pattern inclined in the same direction in the gap, and then removing the embossed patterns specifically includes:

[0026] An electroplating process is used to deposit metal into the gaps between any two adjacent imprinted patterns, at least filling the gaps. The metal includes chromium, the main electroplating salt includes chromic anhydride, the catalyst includes sulfuric acid, the solvent includes deionized water, the temperature is 40℃~80℃, and the current density is 15A / dm³. 2 ~60A / dm 2 ;

[0027] A dry etching process is used to etch back the metal to remove excess metal material from the surface of the imprinted pattern, forming a metal pattern tilted in the same direction in the gap. The process gas includes Cl2, BCl3 and O2, the temperature is 20℃~80℃, the pressure is 5mTorr~50mTorr, the source power is 500W~1000W, and the bias power is 50W~200W.

[0028] The imprinted pattern is removed using a dry etching process. The process gas includes O2, the temperature is 200℃~300℃, the pressure is 100mTorr~1000mTorr, the source power is 500W~3000W, and the bias power is turned off.

[0029] In some embodiments, an ion beam etching process is used to etch the exposed surface of the silicon carbide substrate, wherein argon gas is used to generate an argon ion beam with an ion energy of 100 eV to 600 eV.

[0030] In some embodiments, a wet etching process is used, employing cerium ammonium nitrate and nitric acid to remove the remaining metal pattern.

[0031] In some embodiments, a high-temperature annealing process is used to perform a second treatment on the surface of the first grating, so that the sidewall surface of the first grating melts to drive the melting of the surface atomic layer and make the sidewall surface smooth. When performing high-temperature annealing, an H2 and N2 atmosphere is used, the temperature is above 800°C, and the time is 30 minutes to 2 hours.

[0032] In some embodiments, a dry etching process is used to perform a third treatment on the surface of the first grating to remove the carbon-enriched layer formed on the surface of the first grating due to silicon sublimation caused by high-temperature annealing. The process gas includes H2 and N2, the temperature is 200°C to 300°C, the pressure is 500 mTorr to 5000 mTorr, the source power is 500 W to 3000 W, and the bias power is turned off.

[0033] In some embodiments, a spin-coating process is used to form a carbon-based organic material as a sacrificial layer on the surface of the silicon carbide substrate, covering the first grating. The top of the first grating with defects is exposed from the surface of the sacrificial layer by etching back the sacrificial layer. When etching back the sacrificial layer, the process gas includes O2, the temperature is 60°C to 100°C, the pressure is 5mTorr to 50mTorr, the source power is 500W to 1000W, and the bias power is 50W to 200W.

[0034] In some embodiments, a dry etching process is used to remove the exposed top of the first grating. The process gases include SF6, HBr, H2, N2, and O2. The temperature is 0°C to 60°C, the pressure is 100 mTorr to 5000 mTorr, and the source power is 50 W to 3000 W.

[0035] In some embodiments, a dry etching process is used to remove the sacrificial layer. The process gas includes O2, the temperature is 100°C to 300°C, the pressure is 100mTorr to 500mTorr, the source power is 500W to 4000W, and the bias power is turned off.

[0036] According to a second aspect of this application, embodiments of this application also provide an internal tilted grating for optical glasses, which is obtained using the manufacturing method for an internal tilted grating for optical glasses provided in any of the embodiments of the first aspect described above.

[0037] The embodiments of this application may have, or at least have, the following advantages:

[0038] (1) In the embodiment of this application, when forming the imprinted resist pattern, the mask morphology of the tilted grating is predefined to form the tilted imprinted resist pattern, which is beneficial for the subsequent tilted etching of the silicon carbide substrate. It can effectively reduce the amount of residue generated when the mask is consumed during the tilted etching of the silicon carbide substrate, thereby solving the problem that when the vertical mask is used to etch silicon carbide in the tilted direction, the mask will leave residue when it is consumed, resulting in the sidewall morphology of the formed trench (i.e. the sidewall of the tilted grating) being curved and the surface rough. Then, by performing subsequent processing (second processing, third processing) on ​​the sidewall of the first grating formed by etching, the overall etching structure morphology of the grating is improved and the sidewall roughness is improved, so as to achieve the final overall tilted grating structure and high smoothness of the sidewall.

[0039] (2) In this embodiment of the application, by performing a first treatment on the sidewall surface of the imprinted adhesive pattern along the tilt direction of the imprinted adhesive pattern, the surface roughness of the sidewall of the imprinted adhesive pattern can be reduced; by filling the gap between adjacent imprinted adhesive patterns with metal and removing excess metal material and imprinted adhesive pattern from the surface of the imprinted adhesive pattern, a tilted metal pattern with smooth sidewalls and a sharp corner at the top can be formed. As a mask for etching the silicon carbide substrate, in conjunction with tilting the silicon carbide substrate, the smooth sidewall morphology of the metal pattern can be transferred down, thereby reducing the sidewall roughness of the formed tilted grating (first grating).

[0040] (3) In this embodiment, the surface of the first grating is treated by a high-temperature annealing process. The high temperature can be used to melt the sidewall surface of the first grating to drive the melting of the surface atomic layer, making the sidewall surface smooth. Furthermore, the surface of the first grating is treated by a dry etching process to remove the carbon enrichment layer formed on the surface of the first grating due to silicon sublimation caused by high-temperature annealing. Thus, the effective combination of high-temperature annealing and surface treatment can simultaneously reduce the sidewall roughness and adjust the Si / C ratio of the sidewall surface. This avoids the problems of thermal damage (surface Si loss) and new defects (Si / C ratio imbalance) on the silicon carbide surface that would occur when using high-temperature annealing to reduce sidewall roughness in the past, thereby ensuring the accuracy of the optical element.

[0041] (4) In this embodiment, by using an effective combination of covering a sacrificial layer on the surface of a silicon carbide substrate and removing the exposed top of the first grating, the top region of the first grating with the defect of changing tilt angle is removed, so that the top of the final second grating can maintain the shape of a sharp corner, and the second grating formed has sidewalls with the same tilt angle, reducing the sidewall roughness, thereby reducing light scattering loss, improving diffraction efficiency, enhancing optical performance, and having long-term stability for use.

[0042] Other advantages of this application will be described in the following detailed description. Attached Figure Description

[0043] Figure 1 This is a flowchart illustrating a preferred embodiment of the present application of a method for manufacturing an internal tilted grating for optical glasses.

[0044] Figure 2 This is a schematic diagram of the structure after an imprinting adhesive layer is formed on a silicon carbide substrate, which is a preferred embodiment of this application.

[0045] Figure 3 This is a schematic diagram of the structure after forming an imprinted pattern, provided as a preferred embodiment of this application.

[0046] Figure 4This is a schematic diagram of a structure provided in a preferred embodiment of the present application after filling the gap between adjacent embossed patterns with metal.

[0047] Figure 5 This is a schematic diagram of the structure after metal is etched back to form a metal pattern, which is a preferred embodiment of this application.

[0048] Figure 6 This is a schematic diagram of the structure after removing the embossing adhesive pattern, provided as a preferred embodiment of this application.

[0049] Figure 7 This is a schematic diagram of the structure after etching a silicon carbide substrate to form a first grating, according to a preferred embodiment of this application.

[0050] Figure 8 This is a schematic diagram of the structure after removing the remaining metal pattern, provided as a preferred embodiment of this application.

[0051] Figure 9 This is a schematic diagram of the structure after surface treatment of the first grating, provided as a preferred embodiment of this application.

[0052] Figure 10 This is a schematic diagram of the structure after a sacrificial layer is formed on a silicon carbide substrate, which is a preferred embodiment of this application.

[0053] Figure 11 This is a schematic diagram of the structure after removing the top of the first grating and forming the second grating, according to a preferred embodiment of this application.

[0054] Figure 12 This is a schematic diagram of the structure after removing the sacrificial layer, provided as a preferred embodiment of this application.

[0055] In the figure: 10. Silicon carbide substrate; 101. First grating; 102. Second grating; 11. Imprinted resist layer; 111. Imprinted resist pattern; 112. Gap; 12. Metal; 121. Metal pattern; 13. Sacrificial layer. Detailed Implementation

[0056] To address the problem that conventional processes for fabricating silicon carbide (SiC) tilted gratings in optical glasses often result in high surface roughness on the overall sidewalls, exhibiting a pitted and uneven morphology that leads to significant light scattering loss and reduced diffraction efficiency, this application provides a method for manufacturing a tilted grating inside optical glasses, comprising the following steps:

[0057] Provide silicon carbide substrates;

[0058] Multiple imprinted adhesive patterns that are tilted in the same direction are formed on the surface of the silicon carbide substrate;

[0059] The surface of the embossed pattern is subjected to a first treatment to reduce surface roughness;

[0060] The gap between any two adjacent embossed patterns is filled with metal, and excess metal material on the surface of the embossed patterns is removed to form metal patterns that are inclined in the same direction in the gap, and then the embossed patterns are removed.

[0061] Using the metal pattern as a mask, the exposed surface of the silicon carbide substrate is etched along its tilt direction to form a first grating tilted in the same direction on the silicon carbide substrate, and then the remaining metal pattern is removed.

[0062] The surface of the first grating is subjected to a second treatment to reduce surface roughness;

[0063] The surface of the first grating is subjected to a third processing to remove the enriched layer on the surface;

[0064] A sacrificial layer is applied to the surface of the silicon carbide substrate, exposing the top of the first grating;

[0065] Remove the exposed top of the first grating to form a second grating;

[0066] Remove the sacrificial layer.

[0067] This application also provides an internal tilt grating for optical glasses obtained using the above-described method for manufacturing internal tilt gratings for optical glasses.

[0068] This application embodiment reduces surface roughness by pre-forming a tilted imprinted adhesive pattern and performing a first treatment on the surface of the imprinted adhesive pattern. This allows for the filling of metal into the gaps between adjacent imprinted adhesive patterns, improving the sidewall roughness of the formed metal pattern. Furthermore, after etching the silicon carbide substrate along the tilt direction of the metal pattern, pattern transfer ensures that the sidewalls of the formed first grating also have low roughness. A second and third treatment of the first grating surface further reduces surface roughness and adjusts the Si / C ratio of the sidewall surface. Moreover, by removing the top region of the first grating where the tilt angle changes, the top of the final second grating maintains a sharp corner shape, and the second grating has sidewalls with consistent tilt angles. This improves the overall etched structure morphology of the grating and reduces sidewall roughness, achieving a final tilted grating structure with high sidewall smoothness. This reduces light scattering loss, increases diffraction efficiency, enhances optical performance, and provides long-term stability.

[0069] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0070] refer to Figure 1 This application provides a method for manufacturing an internal tilted grating for optical glasses, comprising the following steps:

[0071] Step S11: Provide a silicon carbide substrate.

[0072] refer to Figure 2 In some embodiments, a silicon carbide (SiC) substrate 10 is used to fabricate a tilted grating (second grating) on ​​the silicon carbide substrate 10, thereby improving the overall etch structure morphology of the grating and improving the sidewall roughness.

[0073] Step S12: Form multiple imprinted adhesive patterns that are tilted in the same direction on the surface of the silicon carbide substrate.

[0074] refer to Figure 2 In some embodiments, firstly, a spin coating process is used to spin coat an imprinting adhesive layer 11 onto the surface of the silicon carbide substrate 10. The imprinting adhesive in the imprinting adhesive layer 11 can be a UV-curable imprinting adhesive or a thermosetting imprinting adhesive.

[0075] Then, a template (not shown) with a grating pattern having a preset tilt direction is aligned and pressed against the surface of the imprinting adhesive layer 11, and an imprinting process is used to imprint the pattern onto the imprinting adhesive layer 11, copying the grating pattern with the preset tilt direction from the template onto the imprinting adhesive layer 11. After demolding, multiple imprinting adhesive patterns 111 are formed on the surface of the silicon carbide substrate 10, and each imprinting adhesive pattern 111 is arranged in the same tilt direction to form an inclined imprinting adhesive pattern 111, such as... Figure 3 As shown. Figure 3 An example is shown where the various embossing patterns 111 are arranged at an angle to the right. This application does not limit the number of embossing patterns formed.

[0076] In some embodiments, the process of defining the imprinted adhesive pattern 111 includes aligning and pressing a transparent soft template with a preset tilted grating pattern onto a silicon carbide substrate 10 coated with an imprinted adhesive layer 11 (using UV-curable imprinted adhesive). Under a specific pressure (e.g., 1 mTorr to 500 mTorr), the imprinted adhesive layer 11 is cured by ultraviolet irradiation, thus replicating the tilted grating pattern on the transparent soft template onto the imprinted adhesive layer 11. After demolding, a gap 112 representing the tilted grating structure is formed on the imprinted adhesive layer 11, and imprinted adhesive patterns 111 tilted in the same direction are formed on both sides of the gap 112.

[0077] In some embodiments, the process of defining the imprinted adhesive pattern 111 includes aligning and pressing a hard template with a preset tilted grating pattern onto a silicon carbide substrate 10 coated with an imprinted adhesive layer 11 (using a thermosetting imprinted adhesive). Under a specific pressure (e.g., 1 mTorr to 500 mTorr), the imprinted adhesive layer 11 is cured by heating, thus replicating the tilted grating pattern on the hard template onto the imprinted adhesive layer 11. After demolding, a gap 112 representing the tilted grating structure is formed on the imprinted adhesive layer 11, and imprinted adhesive patterns 111 tilted in the same direction are formed on both sides of the gap 112.

[0078] The surface of the silicon carbide substrate 10 is exposed from the bottom of the gap 112.

[0079] Step S13: Perform a first treatment on the surface of the embossed pattern to reduce surface roughness.

[0080] The surface of the embossed pattern 111 often has burrs, resulting in a high surface roughness. To prevent the surface roughness of the embossed pattern 111 from being passed on during subsequent pattern transfer processes, the surface of the embossed pattern 111 can be pre-treated to remove the burrs and reduce its surface roughness.

[0081] refer to Figure 3 In some embodiments, a dry etching process is employed, and at a relatively low temperature below 100°C, a first treatment is performed on the sidewall surface of the imprinted resist pattern 111 along its tilt direction to remove burrs present on the surface of the imprinted resist pattern 111, reduce the surface roughness of the sidewall of the imprinted resist pattern 111, and smooth the sidewall surface of the imprinted resist pattern 111. Performing the first treatment on the sidewall surface of the imprinted resist pattern 111 at a relatively low temperature below 100°C will not damage the overall structure of the imprinted resist pattern 111.

[0082] In some embodiments, when performing the first process, the process gas includes O2, the dilution and dissociation gas includes N2, the temperature is 60°C to 100°C, the pressure is 5 mTorr to 50 mTorr, the source power is 500 W to 1000 W, and the bias power is 50 W to 200 W. However, it is not limited to these embodiments.

[0083] Step S14: Form metal patterns that are tilted in the same direction in the gap between adjacent imprinted patterns, and then remove the imprinted patterns.

[0084] refer to Figure 4 In some embodiments, firstly, the gap 112 between any two adjacent imprinted adhesive patterns 111 is filled with metal 12, and the gap 112 is at least completely filled.

[0085] In some embodiments, an electroplating process is used to deposit metal 12 in the gap 112 between any two adjacent embossed patterns 111, filling the gap 112 and covering the surface of the embossed pattern 111 with the deposited metal 12.

[0086] In some embodiments, when performing the electroplating process, the electroplated metal 12 includes chromium (Cr) to form a chromium metal pattern, the main salt includes chromium anhydride, the catalyst includes sulfuric acid, the solvent includes deionized water, the temperature is 40°C to 80°C, and the current density is 15 A / dm³. 2 ~60A / dm 2 However, it is not limited to this.

[0087] refer to Figure 5 Next, a dry etching process is used to etch back the metal 12, removing excess metal 12 material from the surface of the imprinted resist pattern 111. A metal pattern 121, inclined in the same direction as the imprinted resist pattern 111, is formed in the gap 112, serving as a mask for subsequent etching of the silicon carbide substrate 10 surface. The top of the metal pattern 121 formed after the etch back is flush (or substantially flush) with the top surface of the imprinted resist pattern 111 (the surface of the imprinted resist layer 11).

[0088] In some embodiments, when performing the etch-back operation on metal 12, the process gas includes Cl2, BCl3, and O2, the dilution and dissociation gas includes at least one of N2 and Ar, the temperature is 20°C to 80°C, the pressure is 5 mTorr to 50 mTorr, the source power is 500 W to 1000 W, and the bias power is 50 W to 200 W. However, it is not limited to these embodiments.

[0089] refer to Figure 6 Then, a dry etching process is used, employing a high-temperature (above 200°C) unbiased etching method to remove the imprinted resist pattern 111, so that the metal pattern 121 is completely exposed from the surface of the silicon carbide substrate 10. The gaps between adjacent metal patterns 121 are the spaces originally occupied by the imprinted resist pattern 111.

[0090] In some embodiments, when removing the imprinted pattern 111, the process gas includes O2, the dilution and dissociation gas includes at least one of N2 and Ar, the temperature is 200°C to 300°C, the pressure is 100 mTorr to 1000 mTorr, the source power is 500 W to 3000 W, and the bias power is turned off. However, this is not the only possible scenario.

[0091] After the imprinted adhesive pattern 111 undergoes the first treatment to reduce the surface roughness of the sidewalls, the gaps 112 between adjacent imprinted adhesive patterns 111 are filled with metal 12, and excess metal 12 material and imprinted adhesive patterns 111 on the surface of the imprinted adhesive pattern 111 are removed by etching, thus forming an inclined metal pattern 121 with smooth sidewalls and a sharp bend at the top (see reference). Figure 6 The metal pattern 121 is used as a mask for etching the silicon carbide substrate 10. In this way, when the silicon carbide substrate 10 is subsequently etched at an angle, the smooth sidewall morphology of the metal pattern 121 can be effectively transferred, thereby reducing the surface roughness of the sidewall of the formed angled grating (first grating).

[0092] Step S15: Using the metal pattern as a mask, etch the surface of the silicon carbide substrate along its tilt direction to form a first grating tilted in the same direction on the silicon carbide substrate, and then remove the remaining metal pattern.

[0093] refer to Figure 7 In some embodiments, the tilted metal pattern 121 formed in the previous step is used as a mask, and an ion beam etching (IBE) process is used to etch the surface of the silicon carbide substrate 10 exposed in the gap between adjacent metal patterns 121 along the tilt direction of the metal pattern 121, thereby forming a protruding and unidirectionally tilted first grating 101 on the silicon carbide substrate 10.

[0094] By pre-defining the mask morphology of the tilted grating, a tilted imprinted resist pattern 111 is formed, which facilitates the subsequent tilted etching of the silicon carbide substrate 10. This effectively reduces the amount of residue generated when the metal pattern 121 mask is consumed during the tilted etching process of the silicon carbide substrate 10. This solves the problem that when the vertical mask is used to etch silicon carbide in the tilted direction, residue is generated when the mask is consumed, resulting in a curved morphology and rough surface of the sidewall of the formed trench (i.e., the sidewall of the tilted grating).

[0095] In some embodiments, when performing the ion beam etching process, argon gas (Ar) is used to generate an argon ion beam with an ion energy of 100eV to 600eV. By precisely controlling the tilt angle of the sample stage, the direction of the ion beam entering the gap between adjacent metal patterns 121 on the silicon carbide substrate 10 placed on the sample stage is parallel to the sidewall direction of the metal patterns 121, thereby achieving tilt etching of the silicon carbide substrate 10.

[0096] After the ion beam etching process is completed, a first grating 101 (the middle structure of the tilted grating) tilted to the right is formed on the silicon carbide substrate 10. Furthermore, a portion of the metal pattern 121 remaining after etching is also present on the top of the first grating 101. Figure 7 As shown. These remaining metal patterns 121 need to be removed.

[0097] refer to Figure 8 In some embodiments, a wet etching process is used to remove the remaining metal pattern 121 and form a first grating 101 tilted to the right and exposed at the top on the silicon carbide substrate 10. The first grating 101 is formed by etching the silicon carbide substrate 10 and is integrally connected to the silicon carbide substrate 10. The material of the first grating 101 is silicon carbide, which is the same as the material of the silicon carbide substrate 10.

[0098] In some embodiments, when removing the remaining metal pattern 121, a mixture of cerium ammonium nitrate and nitric acid is used to thoroughly remove the remaining Cr metal pattern 121, while the consumption of SiC is extremely low (etch selectivity ratio: Cr:SiC > 100:1), thus well maintaining the etched structure morphology of the first grating 101.

[0099] Step S16: Perform a second treatment on the surface of the first grating to reduce surface roughness.

[0100] The surface of the first grating 101 formed by tilting the silicon carbide substrate 10 using an ion beam etching process may still have a certain degree of roughness. To further reduce the surface roughness of the first grating 101, it can be achieved by further processing the surface of the first grating 101.

[0101] refer to Figure 9 In some embodiments, a high-temperature annealing process is used to perform a second treatment on the surface of the first grating 101. Through high-temperature annealing, the SiC on the sidewall surface of the first grating 101 can be melted and placed in a molten state, which can drive the atomic layers on the sidewall surface of the first grating 101 to melt and move, thereby making the sidewall surface of the first grating 101 smooth and reducing the roughness of the sidewall surface of the first grating 101.

[0102] In some embodiments, when performing high-temperature annealing, a mixed atmosphere of H2 and N2 is used, the temperature is above 800°C, for example, the temperature can be 800°C to 900°C, or the temperature can be 800°C to 1000°C, or the temperature can be 800°C to 1200°C, etc., and the time is 30 minutes to 2 hours. However, it is not limited to this.

[0103] Step S17: Perform a third process on the surface of the first grating to remove the enriched layer on the surface.

[0104] Because high-temperature annealing causes the sublimation of Si in the SiC material on the surface of the first grating 101, resulting in the loss of Si in the SiC material on the surface of the first grating 101, a C-rich layer (not shown) will be formed on the surface of the first grating 101. Therefore, this C-rich layer needs to be removed to avoid the generation of new defects caused by the imbalance of Si / C ratio on the silicon carbide surface.

[0105] refer to Figure 9 In some embodiments, a dry etching process and a high-temperature, unbiased etching method are used to perform a third treatment on the surface of the first grating 101 to remove the carbon-rich layer formed on the surface of the first grating 101 due to silicon sublimation caused by high-temperature annealing.

[0106] In some embodiments, when performing the third process, the process gas includes a mixture of H2 and N2, and Ar is used as a dilution and dissociation gas. The temperature is 200°C to 300°C, the pressure is 500 mTorr to 5000 mTorr, the source power is 500 W to 3000 W, and the bias power is turned off, so that the C chains in the carbon enrichment layer break and volatilize and are removed.

[0107] After removing the carbon-enriched layer from the surface of the first grating 101, the Si / C ratio in the exposed SiC material of the new surface of the first grating 101 will be in a normal state. Thus, through the effective combination of high-temperature annealing and surface etching, the sidewall roughness and the Si / C ratio of the sidewall surface are simultaneously reduced. This avoids the problems of thermal damage (surface Si loss) and new defects (Si / C ratio imbalance) on the silicon carbide surface that would occur when using high-temperature annealing to reduce sidewall roughness in the past, thereby ensuring the accuracy of the optical element.

[0108] Step S18: Remove the top of the first grating to form the second grating.

[0109] After the silicon carbide substrate 10 is etched at an angle, a small amount of metal pattern 121 remains on the top of the first grating 101. This causes the top of the first grating 101 to change its angle after etching, resulting in a curved top morphology and rough surface of the sidewall of the formed trench (i.e., the sidewall of the tilted first grating 101). Therefore, it is necessary to remove the area with the defect of changed tilt angle on the top of the first grating 101.

[0110] refer to Figure 10 In some embodiments, firstly, a carbon-based organic material as a sacrificial layer 13 is formed on the surface of the silicon carbide substrate 10 using a spin-coating process, and the top of the first grating 101 is covered.

[0111] In some embodiments, the carbon-based organic material may be a spin-coated organic carbon layer (SOC), etc.

[0112] Then, a dry etching process is used, and the sacrificial layer 13 is etched back at a lower temperature below 100°C to reduce the height of the surface of the sacrificial layer 13 (reduce the thickness of the sacrificial layer 13), so that the defective top of the first grating 101 is exposed from the surface of the sacrificial layer 13, while protecting the defect-free sidewalls below the top of the first grating 101. The exposed portion of the first grating 101 on the surface of the sacrificial layer 13 is the top portion of the first grating 101 that needs to be removed.

[0113] In some embodiments, when the sacrificial layer 13 is etched back, the process gas includes O2, the dilution and dissociation gas includes N2, the temperature is 60°C to 100°C, the pressure is 5 mTorr to 50 mTorr, the source power is 500 W to 1000 W, and the bias power is 50 W to 200 W. However, it is not limited to these embodiments.

[0114] refer to Figure 11 Next, a dry etching process is used to remove the exposed top of the first grating 101.

[0115] In some embodiments, when removing the exposed top of the first grating 101, the process gas includes SF6, HBr, H2, and N2, as well as O2, the dilution and dissociation gas includes at least one of Ar and He, the temperature is 0°C to 60°C, the pressure is 100 mTorr to 5000 mTorr, and the source power is 50 W to 3000 W.

[0116] After removing the exposed top of the first grating 101, a second grating 102 is formed in the sacrificial layer 13. By employing an effective combination of covering the surface of the silicon carbide substrate 10 with the sacrificial layer 13 and removing the exposed top of the first grating 101, the top region of the first grating 101 with tilt angle change defects is removed, so that the top of the finally formed second grating 102 can maintain the shape of a sharp corner, and the formed second grating 102 has sidewalls with a consistent tilt angle and smooth sidewalls with reduced surface roughness.

[0117] refer to Figure 12 Finally, a dry etching process is used, employing a high-temperature (above 100°C) unbiased etching method to remove the sacrificial layer 13, forming an exposed second grating 102 as a tilted grating on the silicon carbide substrate 10. The second grating 102 has smooth tilted sidewalls, significantly reducing its surface roughness. The sidewalls are generally flat, while the top maintains a sharp corner, which helps reduce light scattering loss, improve diffraction efficiency, enhance optical performance, and ensure long-term stability.

[0118] In some embodiments, when removing the sacrificial layer 13, the process gas includes O2, the dilution and dissociation gas includes at least one of N2 and Ar, the temperature is 100°C to 300°C, the pressure is 100mTorr to 500mTorr, the source power is 500W to 4000W, and the bias power is turned off.

[0119] This application also provides an internal tilted grating for optical glasses, which is obtained using the manufacturing method for internal tilted gratings for optical glasses provided in the above embodiments.

[0120] refer to Figure 12 In some embodiments, the tilted grating inside the optical glasses includes a second grating 102 protruding from the surface of the silicon carbide substrate 10, the second grating 102 being tilted on the surface of the silicon carbide substrate 10. The tilted sidewalls of the second grating 102 have smooth surfaces with low surface roughness, and the sidewalls are generally flat, while the top of the sidewalls maintains a sharp corner shape, reducing light scattering loss, improving diffraction efficiency, enhancing optical performance, and providing long-term stability.

[0121] In some embodiments, the optical glasses may be AI glasses.

[0122] In summary, by pre-forming an inclined imprinting adhesive pattern 111 and performing a first treatment on the surface of the imprinting adhesive pattern 111, the surface roughness is reduced. Therefore, after filling the gap 112 between adjacent imprinting adhesive patterns 111 with metal 12, the sidewall roughness of the formed metal pattern 121 can be improved. Furthermore, after etching the silicon carbide substrate 10 along the inclined direction of the metal pattern 121, the sidewall of the formed first grating 101 can also have low roughness through pattern transfer. Moreover, by performing a second and third treatment on the surface of the first grating 101, it is possible to achieve… Further reducing surface roughness and adjusting the Si / C ratio on the sidewall surface; moreover, by removing the top region of the first grating 101 where the tilt angle change defect exists, the top of the final second grating 102 can maintain a sharp corner shape, and the second grating 102 has sidewalls with consistent tilt angles, improving the overall etching structure morphology of the grating and improving the sidewall roughness, achieving the final overall tilted grating structure and high smoothness of the sidewalls, thereby reducing light scattering loss, improving diffraction efficiency, enhancing optical performance, and possessing long-term stability for use.

[0123] The above are merely preferred embodiments of this application. These embodiments are not intended to limit the scope of protection of this application. Therefore, any equivalent changes made based on the description and drawings of this application should also be included within the scope of protection of this application.

Claims

1. A method for manufacturing an internal tilted grating of optical glasses, characterized in that, In order, they include: Provide silicon carbide substrates; Multiple imprinted adhesive patterns that are tilted in the same direction are formed on the surface of the silicon carbide substrate; The surface of the embossed pattern is subjected to a first treatment to reduce surface roughness; The gap between any two adjacent embossed patterns is filled with metal, and excess metal material on the surface of the embossed patterns is removed to form metal patterns that are inclined in the same direction in the gap, and then the embossed patterns are removed. Using the metal pattern as a mask, the exposed surface of the silicon carbide substrate is etched along its tilt direction to form a first grating tilted in the same direction on the silicon carbide substrate, and then the remaining metal pattern is removed. A high-temperature annealing process is used to perform a second treatment on the surface of the first grating, which melts the sidewall surface of the first grating to drive the melting of the surface atomic layer, making the sidewall surface smooth and reducing the surface roughness. The surface of the first grating is subjected to a third processing to remove the enriched layer on the surface; A sacrificial layer is applied to the surface of the silicon carbide substrate, exposing the top of the first grating; Remove the exposed top of the first grating to form a second grating; Remove the sacrificial layer.

2. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, The process of forming multiple unidirectionally tilted imprinted patterns on the surface of the silicon carbide substrate specifically includes: A spin-coating adhesive layer is applied to the surface of the silicon carbide substrate; A template with a grating pattern having a preset tilt direction is aligned and pressed with the surface of the imprinting adhesive layer, and an imprinting process is used to copy the grating pattern with the preset tilt direction on the template onto the imprinting adhesive layer. After demolding, multiple imprinting adhesive patterns tilted in the same direction are formed on the surface of the silicon carbide substrate.

3. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, The first treatment of the surface of the embossed adhesive pattern specifically includes: A dry etching process is used, and the first treatment is performed on the sidewall surface of the imprinted adhesive pattern along the tilt direction of the imprinted adhesive pattern to reduce the surface roughness of the sidewall of the imprinted adhesive pattern. The process gas includes O2, the temperature is 60℃~100℃, the pressure is 5mTorr~50mTorr, the source power is 500W~1000W, and the bias power is 50W~200W.

4. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, The process of filling the gap between any two adjacent embossed patterns with metal, removing excess metal material from the surface of the embossed patterns, forming unidirectionally inclined metal patterns in the gaps, and then removing the embossed patterns specifically includes: An electroplating process is used to deposit metal into the gaps between any two adjacent imprinted patterns, at least filling the gaps. The metal includes chromium, the main electroplating salt includes chromic anhydride, the catalyst includes sulfuric acid, the solvent includes deionized water, the temperature is 40℃~80℃, and the current density is 15A / dm³. 2 ~60A / dm 2 ; A dry etching process is used to etch back the metal to remove excess metal material from the surface of the imprinted pattern, forming a metal pattern tilted in the same direction in the gap. The process gas includes Cl2, BCl3 and O2, the temperature is 20℃~80℃, the pressure is 5mTorr~50mTorr, the source power is 500W~1000W, and the bias power is 50W~200W. The imprinted pattern is removed using a dry etching process. The process gas includes O2, the temperature is 200℃~300℃, the pressure is 100mTorr~1000mTorr, the source power is 500W~3000W, and the bias power is turned off.

5. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, The exposed surface of the silicon carbide substrate is etched using an ion beam etching process, wherein argon gas is used to generate an argon ion beam with an ion energy of 100eV to 600eV.

6. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, A wet etching process is used, employing cerium ammonium nitrate and nitric acid, to remove the remaining metal pattern.

7. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, When performing high-temperature annealing, use an atmosphere of H2 and N2, a temperature of 800℃ or higher, and a time of 30 minutes to 2 hours.

8. The method for manufacturing an internal tilted grating of optical glasses according to claim 7, characterized in that, A dry etching process is used to perform a third treatment on the surface of the first grating to remove the carbon-enriched layer formed on the surface of the first grating due to silicon sublimation caused by high-temperature annealing. The process gases include H2 and N2, the temperature is 200℃~300℃, the pressure is 500mTorr~5000mTorr, the source power is 500W~3000W, and the bias power is turned off.

9. The method for manufacturing an internal tilted grating of optical glasses according to claim 1, characterized in that, A carbon-based organic material is formed as a sacrificial layer on the surface of the silicon carbide substrate using a spin-coating process to cover the first grating. The top of the defective part of the first grating is exposed from the surface of the sacrificial layer by etching back the sacrificial layer. During the etching back of the sacrificial layer, the process gas includes O2, the temperature is 60℃~100℃, the pressure is 5mTorr~50mTorr, the source power is 500W~1000W, and the bias power is 50W~200W. A dry process is employed. The etching process removes the exposed top of the first grating. The process gases include SF6, HBr, H2, N2, and O2. The temperature is 0℃~60℃, the pressure is 100mTorr~5000mTorr, and the source power is 50W~3000W. The dry etching process removes the sacrificial layer. The process gases include O2. The temperature is 100℃~300℃, the pressure is 100mTorr~500mTorr, the source power is 500W~4000W, and the bias power is turned off.

10. A tilted grating inside optical glasses, characterized in that, It is obtained using the method for manufacturing an internal tilted grating of optical glasses as described in any one of claims 1-9.

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