Blazed grating and preparation method thereof

Abstract

The present invention provides a blazed grating and a method for fabricating the same. The method comprises: depositing a titanium dioxide optical film of uniform thickness on a target substrate; spin-coating an imprint adhesive onto the titanium dioxide optical film using a coating process; imprinting and patterning the imprint adhesive; selecting inductively coupled plasma etching parameters that match the target substrate for etching the titanium dioxide optical film; using the inductively coupled plasma etching parameters to etch the titanium dioxide optical film onto the target substrate to obtain a corresponding blazed grating; and transferring the nanoimprinted pattern using a corresponding inductively coupled plasma etching process based on the inductively coupled plasma etching parameters, thereby etching the titanium dioxide optical film onto the target substrate to obtain a corresponding blazed grating. Through process design and parameter optimization, the present invention fabricates a blazed grating with low roughness, high line density, good pattern fidelity, good blaze angle consistency, and high uniformity.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor optoelectronic technology, and in particular relates to a blazed grating and a preparation method thereof. Background Art

[0002] Blazed gratings have the characteristics of zero-order splitting and extremely high diffraction efficiency, which makes them widely used in monochromators, precision measurement, laser shaping, optical communications, and virtual reality / augmented reality.

[0003] Blazed gratings with a scale of more than one micron are mainly prepared by mechanical scribing (mostly diamond cutting) and holographic ion beam etching. Mechanical scribing is a relatively traditional method for making blazed gratings. Its core step is that on a dedicated grating scribing machine, the working platform drives the grating blank to perform indexing motion according to the grating constant, and the fixed knife bridge with the diamond cutter is installed to perform reciprocating motion. The mechanical scribing method has the characteristics of easy control of the grating groove shape, but when the scale of the grating is reduced to near the visible light wave, there are also problems such as low processing efficiency. Moreover, mechanical scribing forms a slide groove by evaporating or depositing a metal film layer on the grating substrate, and then pressing and moving the diamond cutter on its surface. This method is limited to the size of the tip of the cutter. The slide groove will show different roughness due to the speed of the cutter movement, resulting in a large surface error.

[0004] Blazed gratings with submicron periods must be fabricated via ion beam lithography. This requires high structural precision, with periods less than 300μm and blaze angle radius of curvature less than 10nm. Grayscale exposure is required, and the blaze angle varies significantly. This method also requires a 1:1 etching selectivity ratio between the photoresist and substrate, placing high demands on the ion beam exposure and etching processes. This method is difficult to fabricate, and requires multiple critical steps such as exposure. This leads to high processing costs and significant material limitations, and currently, no stable, reliable, and scalable process has been developed.

[0005] The main process steps of holographic ion beam etching are as follows: photoresist is spin-coated on the substrate, and after holographic exposure and development, a photoresist mask is obtained; then, an ion beam is used for etching, and the photoresist mask is etched by adjusting the angle of the ion beam. The ion bombardment energy generated by the tilted ion beam, combined with the shielding effect of the photoresist, forms a blazed surface; the other blazed surface is then etched by changing the incident angle of the ion beam. The disadvantage of holographic ion beam etching is that this grating is etched purely by ion bombardment, which can cause significant ion damage to the underlying film layer. It also requires precise control of the energy and direction of the ion beam, making the processing extremely difficult.

[0006] In the fabrication of blazed gratings, the level of control over the blaze angle significantly impacts the grating's performance. Existing fabrication processes struggle to achieve precise control of the blaze angle, significantly limiting the fabrication and application of blazed gratings. Furthermore, most current blazed grating fabrication methods remain at the theoretically feasible stage, with few successful large-scale fabrication cases. Therefore, developing a fabrication method that can precisely control the blaze angle and avoid ion damage, in order to achieve superior performance, remains an urgent challenge in this field. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a blazed grating and a method for preparing the same. The preparation method prepares a mask through nanoimprint technology and obtains a high-precision blaze angle through inductively coupled plasma etching technology. While achieving precise control of the blaze angle, it avoids the disadvantage of high ion damage caused by simple ion beam etching, thereby preparing a blazed grating with low roughness, high line density, high graphic fidelity and good blaze angle consistency.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a blazed grating, comprising:

[0010] A titanium dioxide optical film and an embossed adhesive layer are sequentially prepared on a substrate, and the embossed adhesive layer is patterned by nanoimprinting to form a mask layer to obtain a structure to be etched;

[0011] The blazed grating is obtained by performing pattern transfer on the structure to be etched through inductively coupled plasma etching.

[0012] The preparation method of the present invention is specifically as follows:

[0013] Depositing a titanium dioxide optical film with uniform thickness on a target substrate;

[0014] Spin-coating an embossing adhesive on the titanium dioxide optical film by a coating process;

[0015] Imprinting the imprinting adhesive to perform patterning;

[0016] Selecting inductively coupled plasma etching parameters that match the target substrate for etching the titanium dioxide optical thin film; wherein the inductively coupled plasma etching parameters are used to etch the titanium dioxide optical thin film on the target substrate through an etching process to obtain a corresponding blazed grating;

[0017] Based on the inductively coupled plasma etching parameters, the corresponding inductively coupled plasma etching process is used to transfer the nano-imprinted pattern, thereby etching the titanium dioxide optical film on the target substrate to obtain the corresponding blazed grating.

[0018] In the preparation method provided by the present invention, a titanium dioxide optical film is first formed on a target substrate, and then an imprinted adhesive layer is formed on the titanium dioxide optical film. Then, patterning is performed using nanoimprint technology to form a mask layer. The structure to be etched is then etched using inductively coupled plasma (ICP) technology to transfer the pattern of the mask layer to the titanium dioxide optical film, thereby forming a titanium dioxide blazed grating. In the ICP pattern transfer process, a combination of fluorine-based and bromine-based gases is preferably used as the processing gas, and the bromine-based gas preferably includes HBr. The fluorine-based gas primarily serves as the etching gas, and the bromine-based gas (e.g., HBr) can act as a protective gas. On the one hand, HBr easily dissociates to form hydrogen to form a polymer with the imprinted adhesive, and Br can react with elements doped in the imprinted adhesive (e.g., Si) to form a non-volatile substance (e.g., SiBr4) that adheres to the blazed and anti-blazed surfaces of the imprinted grating, protecting them and reducing the amount of etching on the imprinted adhesive. The present invention adopts ICP technology for pattern transfer, combining physical etching, chemical etching and polymer deposition to achieve an etching selectivity ratio of 1:1 between the mask material and the TiO2 layer, realizing precise control of the blaze angle, thereby obtaining a high-precision blaze angle. In addition, the ICP method eliminates the disadvantage of high ion damage caused by simple ion beam etching, and prepares a blazed grating with low roughness, high line density, high pattern fidelity and good blaze angle consistency.

[0019] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0020] The blazed grating of the present invention, as an optical device, requires the selection of appropriate optical materials and a satisfactory manufacturing process during its fabrication. The optical parameters (refractive index, transmittance, reflectivity), physical properties (hardness, deformation, bubble content, Poisson's ratio), and temperature characteristics (thermal expansion coefficient) of the optical material all affect the performance of the optical device and system.

[0021] For example, the substrate may be any one of a silicon substrate, a glass substrate, a transparent or semi-transparent optical crystal, a special optical material, a polymer substrate, and a silicon carbide substrate.

[0022] Preferably, the substrate includes any one of a silicon substrate, a glass substrate, a silicon dioxide substrate, a silicon carbide substrate or a polymer substrate, more preferably a glass substrate, and even more preferably a high-refractive glass substrate.

[0023] Preferably, the polymer substrate comprises a polyester substrate, illustratively including but not limited to: any one or a combination of at least two of polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polymethyl methacrylate (PMMA).

[0024] Preferably, the substrate is a cleaned substrate.

[0025] Preferably, the cleaning solution includes an acidic oxidizing cleaning solution and water. The acidic oxidizing cleaning solution can remove organic impurities and the like on the surface of the substrate; and the water is used to rinse away the acidic oxidizing cleaning solution remaining on the surface of the substrate.

[0026] Preferably, the acidic oxidizing cleaning solution comprises a combination of H2SO4, HF, H2O2 and water; the ratio of the oxidizing components (H2O2, H2SO4) and the acidic components (H2SO4, HF) can be adjusted according to actual cleaning requirements.

[0027] Preferably, the cleaning temperature of the acidic oxidizing cleaning solution is 80-100°C, for example, it can be 82°C, 85°C, 88°C, 90°C, 92°C, 95°C or 98°C.

[0028] Preferably, the cleaning time of the acidic oxidizing washing solution is 10-60s, for example, it can be 12s, 15s, 18s, 20s, 22s, 25s, 28s, 30s, 35s, 40s, 45s, 50s or 55s, and more preferably 15-20s.

[0029] Preferably, the water cleaning time is 10-60s, for example, it can be 12s, 15s, 18s, 20s, 22s, 25s, 28s, 30s, 35s, 40s, 45s, 50s or 55s.

[0030] In a preferred technical solution, before depositing a titanium dioxide optical film with uniform thickness on the target substrate, the method further includes:

[0031] said selecting a prefabricated substrate;

[0032] removing organic impurities from the prefabricated substrate by a strong oxidizing water washing solution;

[0033] The residual acid on the prefabricated substrate is rinsed clean with a deionized water solution to form a target substrate.

[0034] In a preferred technical solution, removing organic impurities from the prefabricated substrate by a strong oxidizing water washing solution comprises:

[0035] A strongly oxidizing aqueous solution of the following composition: H2SO4:HF:H2O2:H2O=X:15:Y:60 is heated to 80-100°C to clean the prefabricated substrate for 15-20s, wherein X is preferably 5-30 (for example, 6, 8, 10, 12, 15, 18, 20, 22, 25, 28, etc.), and Y is preferably 5-30 (for example, 6, 8, 10, 12, 15, 18, 20, 22, 25, 28, etc.).

[0036] Preferably, the thickness of the titanium dioxide optical film is 100-200 nm, for example, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm or 190 nm.

[0037] Preferably, the preparation method of the titanium dioxide optical film includes any one of atomic layer deposition (ALD), magnetron sputtering, ion beam deposition, electron beam evaporation, chemical vapor deposition or sol-gel method, and magnetron sputtering or ion beam deposition is more preferred.

[0038] Illustratively, the present invention forms the titanium dioxide optical thin film by a magnetron sputtering method.

[0039] Preferably, the target material for magnetron sputtering is a cylindrical rotating target material.

[0040] Preferably, the pressure of the magnetron sputtering is 5-100 mtorr, for example, 8 mtorr, 10 mtorr, 13 mtorr, 15 mtorr, 20 mtorr, 30 mtorr, 40 mtorr, 50 mtorr, 60 mtorr, 70 mtorr, 80 mtorr or 90 mtorr, and more preferably 5-13 mtorr.

[0041] Preferably, the power of the magnetron sputtering is 200-300 W, for example, 210 W, 220 W, 230 W, 240 W, 250 W, 260 W, 270 W, 280 W or 290 W.

[0042] Preferably, the radio frequency (RF) voltage of the magnetron sputtering is 400-500 V, for example, 410 V, 420 V, 430 V, 440 V, 450 V, 460 V, 470 V, 480 V or 490 V.

[0043] Preferably, the temperature of the magnetron sputtering is 20-30°C, for example, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C or 29°C.

[0044] Preferably, the processing gas for magnetron sputtering includes Ar and O2.

[0045] Preferably, the flow rate of Ar is 30-60 sccm, for example, 35 sccm, 40 sccm, 45 sccm, 50 sccm or 55 sccm.

[0046] Preferably, the flow rate of O2 is 1-5 sccm, for example, it can be 1.5 sccm, 2 sccm, 2.5 sccm, 3 sccm, 3.5 sccm, 4 sccm or 4.5 sccm.

[0047] Preferably, the magnetron sputtering time is 10-40 min, for example, it can be 12 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, 35 min, 35 min or 38 min.

[0048] Preferably, the distance (Z) between the target and the substrate in the magnetron sputtering is 2-5 mm, for example, it can be 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm or 4.8 mm.

[0049] Preferably, the tilting angle of the ion gun in the magnetron sputtering is 3-10°, for example, 4°, 5°, 6°, 7°, 8° or 9°.

[0050] Preferably, the target pole shoe rotation angle (rotation) in the magnetron sputtering is 5-30° / min, for example, it can be 6° / min, 8° / min, 10° / min, 12° / min, 15° / min, 18° / min, 20° / min, 22° / min, 25° / min or 28° / min.

[0051] In a preferred technical solution, depositing a titanium dioxide optical film with uniform thickness on a target substrate comprises:

[0052] Titanium dioxide optical film is sputtered by magnetron sputtering. The target material is a cylindrical rotating target material. The process parameters are as follows: pressure is 5-100mtorr, power is 200-300W, temperature is 20-30℃, RF voltage is 400-500V, Ar flow rate is 30-60sccm, O2 flow rate is 1-5sccm, the distance between the target and the substrate is 2-5mm, the ion gun tilt angle is 3-10°, the target pole shoe rotation angle is 5-30° / min, the time is 10-40min, and the thickness of the titanium dioxide optical film is 100-200nm.

[0053] Illustratively, the present invention forms the titanium dioxide optical thin film by an ion beam deposition method.

[0054] Preferably, the beam voltage of the deposition light beam of the ion beam deposition is 800-1500V, for example, 900V, 1000V, 1100V, 1200V, 1300V or 1400V.

[0055] Preferably, the beam current of the deposition beam of the ion beam deposition is 100-500 mA, for example, 150 mA, 200 mA, 250 mA, 300 mA, 350 mA, 400 mA or 450 mA.

[0056] Preferably, the ignition RF power of the deposition beam of the ion beam deposition is 200-500W, for example, 250W, 300W, 350W, 400W or 450W.

[0057] Preferably, the suppressor voltage of the deposition beam of the ion beam deposition is 50-200V, for example, 60V, 80V, 100V, 120V, 150V or 180V.

[0058] Preferably, the process gas of the deposition beam of the ion beam deposition comprises Xe.

[0059] Preferably, the flow rate of Xe is 1-10 sccm, for example, it can be 2 sccm, 3 sccm, 4 sccm, 5 sccm, 6 sccm, 7 sccm, 8 sccm or 9 sccm.

[0060] Preferably, the beam voltage of the auxiliary beam of the ion beam deposition is 20-100V, for example, 30V, 40V, 50V, 60V, 70V, 80V or 90V.

[0061] Preferably, the beam current of the auxiliary beam of the ion beam deposition is 300-500 mA, for example, 320 mA, 350 mA, 380 mA, 400 mA, 420 mA, 450 mA or 480 mA.

[0062] Preferably, the ignition RF power of the auxiliary beam of the ion beam deposition is 300-500W or the like.

[0063] Preferably, the suppressor voltage of the auxiliary beam of the ion beam deposition is 200-800V, for example, 300V, 400V, 500V, 600V or 700V.

[0064] Preferably, the Ti incident angle (Ti Target angle) of the auxiliary beam of the ion beam deposition is 30-60°, for example, it can be 32°, 35°, 38°, 40°, 42°, 45°, 48°, 50°, 52°, 55° or 58°.

[0065] Preferably, the process gas of the auxiliary beam of the ion beam deposition includes a combination of O2 and Ar.

[0066] Preferably, the flow rate of O2 is 5-50sccm, for example, it can be 8sccm, 10sccm, 15sccm, 20sccm, 25sccm, 30sccm, 35sccm, 40sccm or 45sccm.

[0067] Preferably, the flow rate of Ar is 1-10 sccm, for example, it can be 2 sccm, 3 sccm, 4 sccm, 5 sccm, 6 sccm, 7 sccm, 8 sccm or 9 sccm.

[0068] Preferably, the ion beam deposition time is 10-60 min, for example, it can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min or 55 min.

[0069] Preferably, in the ion beam deposition method, the deposition speed can be controlled by adjusting the power and O2 flow rate in the auxiliary beam.

[0070] In a preferred technical solution, a titanium dioxide optical film is deposited by ion beam deposition, and the process parameters of the deposition beam are as follows: beam voltage of 800-1500V, beam current of 100-500mA, ignition RF power of 200-500W, suppressor voltage of 50-200V, and Xe flow rate of 1-10sccm; the process parameters of the auxiliary beam are as follows: beam voltage of 20-100V, beam current of 300-500mA, ignition RF power of 300-500W, suppressor voltage of 200-800V, O2 flow rate of 5-50sccm, Ar flow rate of 1-10sccm, Ti incident angle of 30-60°, and ion beam deposition time of 10-60min; the deposition speed is controlled by adjusting the power and O2 flow rate in the auxiliary beam.

[0071] Illustratively, the method for preparing the embossed adhesive layer includes any one of a spin coating method, a spray coating method, a slit coating method, or a roll-to-roll coating method.

[0072] Preferably, the method for preparing the embossed adhesive layer includes a spin coating method.

[0073] Preferably, the spin coating dripping rate is 1-5 mL / s, for example, it can be 1.5 mL / s, 2 mL / s, 2.5 mL / s, 3 mL / s, 3.5 mL / s, 4 mL / s or 4.5 mL / s.

[0074] Preferably, the turntable speed of the spin coating is 1000-6000 rpm, for example, it can be 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, 5000 rpm or 5500 rpm.

[0075] Preferably, the acceleration of the spin coating is 200-1000rpm / s, for example, it can be 250rpm / s, 300rpm / s, 350rpm / s, 400rpm / s, 450rpm / s, 500rpm / s, 550rpm / s, 600rpm / s, 650rpm / s, 700rpm / s, 750rpm / s, 800rpm / s, 850rpm / s, 900rpm / s or 950rpm / s, etc.

[0076] Preferably, the spin coating time is 20-90 s, for example, it can be 25 s, 30 s, 35 s, 40 s, 45 s, 50 s, 55 s, 60 s, 65 s, 70 s, 75 s, 80 s or 85 s.

[0077] Preferably, the thickness of the embossed adhesive layer is 200-400 nm, for example, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 350 nm or 380 nm.

[0078] In a preferred technical solution, a spin-coated embossing adhesive is applied to the titanium dioxide optical film by a coating process, comprising:

[0079] The spin coating process is set with the following working parameters: the glue dripping rate is 1-5 mL / s, the turntable speed is set to 1000-6000 rpm, the acceleration is set to 200-1000 rpm / s, and the time is set to 20-90 s; based on the working parameters, the embossed glue is spin-coated on the titanium dioxide optical film through a coating process.

[0080] In the present invention, a predetermined nanoimprint master is used to perform nanoimprinting on an imprint adhesive to perform patterning.

[0081] Preferably, the patterning further includes a soft baking and / or UV curing step.

[0082] As a preferred technical solution of the present invention, the patterning step also includes a post-processing step, which includes soft baking and / or UV curing, to achieve a better masking effect for the imprint adhesive. Specifically, the soft baking can evaporate moisture, solvents, etc. in the imprint adhesive, enhancing the etching resistance of the top mask layer; the UV curing can promote cross-linking of the polymer in the imprint adhesive, enhancing its etching resistance.

[0083] Preferably, the soft baking pressure is 5-500 mtorr, for example, 10 mtorr, 50 mtorr, 100 mtorr, 150 mtorr, 200 mtorr, 250 mtorr, 300 mtorr, 350 mtorr, 400 mtorr or 450 mtorr.

[0084] Preferably, the soft baking includes a first stage baking and a second stage baking performed sequentially.

[0085] Preferably, the temperature of the first baking stage is 80-100°C, for example, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C or 98°C.

[0086] Preferably, the heating rate to the temperature of the first baking stage is 1-5°C / s, for example, it can be 1.5°C / s, 2°C / s, 2.5°C / s, 3°C / s, 3.5°C / s, 4°C / s or 4.5°C / s.

[0087] Preferably, the first baking time is 10-20 seconds, for example, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, 16 seconds, 17 seconds, 18 seconds or 19 seconds.

[0088] Preferably, the temperature of the second baking stage is 110-130°C, for example, 112°C, 115°C, 118°C, 120°C, 122°C, 125°C or 128°C.

[0089] Preferably, the second baking time is 30-120s, for example, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, etc.

[0090] Preferably, the heating rate to the temperature of the second baking stage is 0.5-2°C / s, for example, 0.6°C / s, 0.8°C / s, 1°C / s, 1.2°C / s, 1.5°C / s or 1.8°C / s.

[0091] Preferably, the soft baking steps are as follows: evacuate to 5-500 mtorr, first heat up to 80-100°C at a rate of 1-5°C / s, hold the temperature for 10-20s, so that the moisture in the embossing glue gradually evaporates; then heat up to 110-130°C at a rate of 0.5-2°C / s, hold the temperature for 30-120s, start to drop the ejector pin so that the substrate can directly contact the hot plate. During the early heating process, a large amount of solvent evaporates, thereby avoiding uneven evaporation of moisture in the embossing glue due to rapid heating, which affects the subsequent etching effect.

[0092] In a preferred technical solution, after spin-coating the embossing adhesive on the titanium dioxide optical film by a coating process, the method includes:

[0093] placing the target substrate with the embossing adhesive in a soft oven, wherein the soft oven has a heating plate, and the target substrate is not in contact with the heating plate;

[0094] Evacuate the soft oven to 5-500 mtorr;

[0095] According to the heating process, the soft oven is heated from 25°C to 80-100°C within 30 seconds, and then kept warm for 10-20 seconds to allow the moisture in the embossing glue to gradually evaporate;

[0096] The temperature of the soft oven was raised from 90°C to 110-130°C within 30s, and the target substrate was directly contacted with the heating plate.

[0097] Preferably, the temperature of the UV curing is 100-220°C, for example, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or 210°C.

[0098] Preferably, the UV curing time is 5-60 s, for example, it can be 10 s, 15 s, 20 s, 25 s, 30 s, 35 s, 40 s, 45 s, 50 s or 55 s.

[0099] As a preferred technical solution of the present invention, the UV curing includes a first stage curing, a second stage curing and a third stage curing performed sequentially.

[0100] The curing temperature of the first stage is 100-120°C, for example, 102°C, 105°C, 108°C, 110°C, 112°C, 115°C or 118°C.

[0101] Preferably, the first curing period is 1-10 seconds, for example, 2 seconds, 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, 8 seconds or 9 seconds.

[0102] Preferably, the UV lamp mode of the first stage of curing is a flash mode (flash lamp mode).

[0103] Preferably, the temperature of the second stage curing is 180-220°C, for example, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C or 215°C.

[0104] Preferably, the second curing time is 1-5 s, for example, 1.5 s, 2 s, 2.5 s, 3 s, 3.5 s, 4 s or 4.5 s.

[0105] Preferably, the UV lamp mode of the second stage of curing is low mode (low power mode).

[0106] Preferably, the temperature of the third stage curing is 180-220°C, for example, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C or 215°C.

[0107] Preferably, the third curing period is 5-20 seconds, for example, 6 seconds, 8 seconds, 10 seconds, 12 seconds, 15 seconds or 18 seconds.

[0108] Preferably, the UV lamp mode of the third stage of curing is high mode (high power mode), which promotes cross-linking reaction of the polymer in the imprint glue to enhance its etching resistance. Finally, the temperature heater is turned off and the device is left to stand for 10-20 seconds (for example, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, 16 seconds, 17 seconds, 18 seconds, 19 seconds, etc.) before being taken out.

[0109] In a preferred technical solution, after spin-coating the embossing adhesive on the titanium dioxide optical film by a coating process, the method includes:

[0110] The parameters of the UV lamp curing process are set as follows: first, set the curing temperature to 100-120°C, the time to 1-10s, and the UV lamp mode to flash mode, then set the temperature to 180-220°C, the time to 1-5s, the UV lamp mode to low power mode, and then adjust the UV lamp mode to high power mode. In high power mode, the polymer in the imprint glue is cross-linked to enhance its etching resistance; finally, turn off the temperature heater, let it stand for 10-20s, and then take it out.

[0111] Preferably, before the pattern transfer, the method further includes a step of modifying the base coat of the structure to be etched.

[0112] Preferably, the primer modification method is an inductively coupled plasma (ICP) etching method.

[0113] Since the residue of primer cannot be effectively avoided during the nanoimprinting process, the amount of residue will directly affect the etching effect of the subsequent pattern. Figure 2 As shown, d) is getting smaller and smaller, reaching the nanometer level. Reducing the residual amount of primer through the imprinting process during nanoimprinting has become an urgent problem to be solved in this field. In order to optimize the preparation effect of the blazed grating, the residual amount of primer is required to be less than 5% of the grating height, so as to minimize the impact on the subsequent etching morphology. When the residual amount of primer is greater than 5% of the grating height, it is necessary to modify the primer through the etching process to achieve the effect of complete removal. As the preferred technical solution of the present invention, the primer is modified by ICP technology, thereby effectively reducing the residual amount of primer.

[0114] Preferably, the processing gas for primer modification includes a combination of CHF3 and CF4; wherein, CHF3 has a smaller etching amount on the imprint glue, and the dissociated H can form a polymer with the imprint glue, thereby protecting the blaze angle.

[0115] Preferably, the flow ratio of CHF3 to CF4 in the primer-modified processing gas is (2.5-3.5):1, for example, it can be 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1 or 3.4:1, etc.

[0116] Preferably, the flow rate of CHF3 in the processing gas modified by the primer is 10-100sccm, for example, it can be 20sccm, 30sccm, 40sccm, 50sccm, 60sccm, 70sccm, 80sccm or 90sccm.

[0117] Preferably, the flow rate of CF4 in the processing gas for primer modification is 5-40 sccm, for example, it can be 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm or 35 sccm.

[0118] Alternatively, preferably, the processing gas for primer modification includes a combination of O2 and N2.

[0119] Preferably, the flow ratio of O2 to N2 in the primer-modified processing gas is 1:(1-4), for example, it can be 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.2, 1:3.5 or 1:3.8, etc.

[0120] Preferably, the flow rate of O2 in the processing gas for primer modification is 5-40sccm, for example, it can be 10sccm, 15sccm, 20sccm, 25sccm, 30sccm or 35sccm, and more preferably 20-40sccm.

[0121] Preferably, the flow rate of N2 in the processing gas for primer modification is 10-100sccm, for example, it can be 20sccm, 30sccm, 40sccm, 50sccm, 60sccm, 70sccm, 80sccm or 90sccm, and more preferably 40-60sccm.

[0122] Preferably, the pressure of the primer modification is 5-100 mtorr, for example, 10 mtorr, 20 mtorr, 30 mtorr, 40 mtorr, 50 mtorr, 60 mtorr, 70 mtorr, 80 mtorr or 90 mtorr, and more preferably 5-30 mtorr.

[0123] Preferably, the source power of the primer modification is 400-700W, for example, it can be 420W, 450W, 480W, 500W, 520W, 550W, 580W, 600W, 620W, 650W or 680W.

[0124] Preferably, the bias power of the primer modification is 5-15% of the source power, for example, it can be 6%, 7%, 8%, 9%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14% or 14.5%, etc.

[0125] Preferably, the bias power of the primer modification is 5-100W, for example, it can be 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W or 90W.

[0126] Preferably, the etching time of the primer modification is 5-100s, for example, it can be 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s or 90s, and more preferably 20-70s.

[0127] In a preferred technical solution, after the embossing adhesive is embossed and patterned, the method further includes:

[0128] The embossing adhesive on the target substrate after patterning is modified so that the residual amount of the primer on the target substrate is less than 5% of the grating height.

[0129] In a preferred technical solution, the imprint adhesive on the target substrate after patterning is modified, and the parameters are set as follows:

[0130] The pressure is 5-100 mtorr, the source power is 400-700 W, the bias power is 5%-15% of the source power, the flow ratio of CHF3 to CF4 in the process gas is (2.5-3.5):1, the flow rate of CHF3 is 10-100 sccm, the flow rate of CF4 is 5-40 sccm, and the etching time is 5-100 s.

[0131] Preferably, the pattern transfer process gas includes a combination of a fluorine-based gas and a bromine-based gas.

[0132] Preferably, the pattern-transferring fluorine-based gas comprises a combination of CHF3 and CF4.

[0133] Preferably, the flow ratio of CHF3 to CF4 in the fluorine-based gas for pattern transfer is (3-5):1, for example, it can be 3.2:1, 3.5:1, 3.8:1, 4:1, 4.2:1, 4.5:1 or 4.8:1.

[0134] As a preferred technical solution of the present invention, ICP technology is used for etching to transfer the pattern of the mask layer to the titanium dioxide optical film to form a titanium dioxide blazed grating, wherein the etching gas includes a fluorine-based gas, which is a combination of CHF3 and CF4. By controlling the flow ratio of CHF3 and CF4 to (3-5):1 and coordinating with the protective gas HBr, an effective combination of physical etching, chemical etching and polymer deposition is achieved, and an etching selectivity ratio of 1:1 between the mask material and the TiO2 layer is achieved, thereby obtaining a high-precision blaze angle and preparing a blazed grating with low roughness, high line density, good pattern fidelity and good blaze angle consistency. If the gas flow of CHF3 is insufficient and the flow of CF4 is too high, the etching speed will be too fast, the blaze surface and blaze angle will not be adequately protected, the etching morphology will be affected, and the fidelity of the pattern will be reduced; if the flow of CHF3 is too high and the flow of CF4 is insufficient, the etching rate and etching uniformity will be affected; and, if the flow ratio of CHF3 to CF4 exceeds the aforementioned preferred range, when the flow of the bromine-based gas HBr remains unchanged, the blaze angle or anti-blaze angle of the grating will be etched too quickly to form a concave ridge, causing etching defects and further affecting the reliability of the grating optical device.

[0135] Preferably, the flow rate of CHF3 in the fluorine-based gas for pattern transfer is 10-200 sccm, for example, 20 sccm, 50 sccm, 80 sccm, 100 sccm, 120 sccm, 150 sccm or 180 sccm, and more preferably 30-100 sccm.

[0136] Preferably, the flow rate of CF4 in the fluorine-based gas for pattern transfer is 1-200 sccm, for example, it can be 5 sccm, 10 sccm, 30 sccm, 50 sccm, 80 sccm, 100 sccm, 120 sccm, 150 sccm or 180 sccm, etc., more preferably 5-100 sccm.

[0137] Preferably, the flow ratio of the fluorine-based gas to HBr is 1:(0.5-1.35), for example, it can be 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2 or 1:1.3, etc.

[0138] Preferably, the flow rate of HBr is 10-300 sccm, for example, it can be 20 sccm, 50 sccm, 80 sccm, 100 sccm, 120 sccm, 150 sccm, 180 sccm, 200 sccm, 220 sccm, 250 sccm or 280 sccm, and more preferably 30-250 sccm.

[0139] Preferably, the pressure of the pattern transfer is 5-100 mtorr, for example, 10 mtorr, 20 mtorr, 30 mtorr, 40 mtorr, 50 mtorr, 60 mtorr, 70 mtorr, 80 mtorr or 90 mtorr, and more preferably 5-80 mtorr.

[0140] Preferably, the temperature of the pattern transfer is 20-100°C, for example, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, more preferably 50-70°C.

[0141] Preferably, the source power of the pattern transfer is 100-1000W, for example, 200W, 300W, 400W, 500W, 600W, 700W, 800W or 900W, and more preferably 200-700W.

[0142] Preferably, the bias power of the pattern transfer is ≤200W, for example, it can be 10W, 20W, 50W, 80W, 100W, 120W, 150W or 180W, and more preferably 50-200W.

[0143] Preferably, the bias power of the pattern transfer is 10-30% of the source power, for example, it can be 12%, 15%, 16%, 18%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28% or 29%, etc.

[0144] Preferably, the etching time for the pattern transfer is 60-180s, for example, it can be 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, 160s or 170s.

[0145] In a preferred technical solution, inductively coupled plasma etching parameters that match the target substrate for etching titanium dioxide optical thin films are selected, including: the chamber temperature of the inductively coupled plasma etching is 20-100°C, the chamber pressure is 5-100 mtorr, the etching gas includes a fluorine-based gas and HBr, the fluorine-based gas is CHF3 and CF4, the flow ratio of CHF3 to CF4 is (3-5):1, the flow rate of CF4 is 1-200 sccm, the flow rate of CHF3 is 10-200 sccm, and the fluorine-based gas is HBr. The flow ratio of gas to HBr is 1:(0.5-1.35), the flow rate of HBr is 10-300sccm, the source power is 100-1000W, the bias power is 10-30% of the source power, the bias power is 0-200W, and the etching time is 60-180s; the grating morphology at different positions is measured to determine the etching uniformity, grating height, blaze angle and anti-blaze angle; when the etching uniformity, grating height, blaze angle and anti-blaze angle meet the conditions, it is determined that the corresponding blazed grating is etched on the target substrate.

[0146] Preferably, the step of removing the glue is further included after the pattern transfer is completed.

[0147] Preferably, the stripping includes dry stripping and / or wet stripping, and more preferably a combination of dry stripping and wet stripping.

[0148] Preferably, the temperature of the dry degumming process is 20-300°C, for example, 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C or 280°C, and more preferably 20-250°C.

[0149] Preferably, the processing time of the dry desizing process is 1-10 min, for example, it can be 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min or 9 min.

[0150] Preferably, the power of the dry stripping method is 500-1500W, for example, it can be 600W, 700W, 800W, 900W, 1000W, 1100W, 1200W, 1300W or 1400W.

[0151] Preferably, the processing gas for dry stripping includes any one of O2, CF4, H2, and N2, or a combination of at least two of them.

[0152] Preferably, the dry stripping includes a first stripping and a second stripping performed sequentially, the processing gas of the first stripping includes O2 and optionally CF4, and the processing gas of the second stripping includes O2, N2 and optionally H2.

[0153] As a preferred technical solution of the present invention, the first degumming process adopts a combination of O2 and CF4, and CF4 can react with the Si component in the imprint glue to remove the mask and residual glue; the second degumming process adopts a combination of O2 and N2, or a combination of O2 and N2 / H2 mixed gas, wherein H2 has reducing properties and can further react fully with the residual glue to improve the removal effect of the mask and residual glue.

[0154] Preferably, the flow rate of O2 in the processing gas of the first stripping and the second stripping is independently 1000-5000sccm, for example, it can be 1500sccm, 2000sccm, 2500sccm, 3000sccm, 3500sccm, 4000sccm or 4500sccm, etc.

[0155] Preferably, the flow rate of CF4 in the first degumming processing gas is ≤50sccm, for example, it can be 5sccm, 10sccm, 15sccm, 20sccm, 25sccm, 30sccm, 35sccm, 40sccm or 45sccm, etc.

[0156] Preferably, the flow rates of N2 and N2 / H2 mixed gas in the second degumming process gas are independently 100-1000sccm, for example, 200sccm, 300sccm, 400sccm, 500sccm, 600sccm, 700sccm, 800sccm or 900sccm, etc.

[0157] Preferably, the time for the first stripping and the second stripping is independently 1-5 minutes, for example, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes or 4.5 minutes.

[0158] Preferably, the wet stripping agent includes an organic solvent.

[0159] Preferably, the wet stripping agent includes a combination of an organic solvent and water to rinse the TiO2 surface.

[0160] In a preferred technical solution, the preparation method further comprises:

[0161] removing the mask glue on the blazed grating by dry glue removal;

[0162] The residual glue on the blazed grating is removed by wet debonding.

[0163] In a preferred technical solution, the masking glue on the blazed grating is removed by dry stripping, comprising:

[0164] The blazed grating is transferred to a debonding process chamber by a robotic arm. The temperature of the debonding process chamber is set at 20-300°C. First, the mask adhesive is removed by introducing process gases with a flow rate of 1000-5000sccm of O2, a flow rate of 0-50sccm of CF4, and a flow rate of 100-1000sccm of N2 / H2 mixed gas or N2. The process debonding time is set.

[0165] Then set the flow rate of the process gas N2 / H2 mixed gas into the debonding process chamber to 100-1000sccm, the flow rate of O2 to 1000-5000sccm, the power to 500-1500W, and debond for 1-5 minutes to remove the residual glue;

[0166] The step of removing residual adhesive on the blazed grating by wet debonding comprises:

[0167] The TiO2 surface was rinsed with an organic solution.

[0168] Preferably, the preparation method specifically comprises the following steps:

[0169] (1) preparing a titanium dioxide optical film with a thickness of 100-200 nm on a substrate;

[0170] (2) coating an embossed adhesive layer with a thickness of 200-400 nm on the titanium dioxide optical film, patterning the embossed adhesive layer by nanoimprinting, and then post-processing to form a mask layer to obtain a structure to be etched;

[0171] The post-treatment method is soft baking and / or UV curing;

[0172] The soft baking pressure is 5-500 mtorr, firstly the temperature is raised to 80-100°C at a rate of 1-5°C / s, held at temperature for 10-20s, then the temperature is raised to 110-130°C at a rate of 0.5-2°C / s, held at temperature for 30-120s;

[0173] The UV curing temperature is 100-220°C and the time is 5-60s;

[0174] (3) performing primer modification and pattern transfer on the structure to be etched by inductively coupled plasma etching to obtain a titanium dioxide blazed grating;

[0175] The processing gas for the primer modification includes CHF3 and CF4 with a flow ratio of (2.5-3.5):1, the source power is 400-700W, the bias power is 10-15% of the source power, and the etching time is 5-100s;

[0176] The processing gas for the pattern transfer includes a fluorine-based gas and HBr at a flow ratio of 1:(0.5-1.35), and the fluorine-based gas includes CHF3 and CF4 at a flow ratio of (3-5):1; the pressure of the pattern transfer is 5-100 mtorr, the temperature is 20-100°C, the source power is 100-1000W, the bias power is 10-30% of the source power, and the etching time is 60-180s;

[0177] (4) Dry debonding and wet debonding are performed on the titanium dioxide blazed grating to obtain the blazed grating.

[0178] In a second aspect, the present invention provides a blazed grating, which is prepared by the preparation method described in the first aspect.

[0179] In a third aspect, the present invention provides a semiconductor working device, wherein the working device prepares a blazed grating by the preparation method described in the first aspect.

[0180] Preferably, the working device at least includes an inductively coupled plasma etcher, a coating device and an imprinting device.

[0181] Compared with the prior art, the present invention has the following beneficial effects:

[0182] The present invention provides a method for fabricating a blazed grating. A mask is prepared using nanoimprinting technology, and pattern transfer is performed using ICP technology. This method combines physical etching, chemical etching, and polymer deposition to achieve a 1:1 etching selectivity ratio between the mask material and the TiO2 layer, enabling precise control of the blaze angle and achieving high-precision blaze angles. Furthermore, the ICP pattern transfer method eliminates the high ion damage associated with simple ion beam etching. Through process design and parameter optimization, the present invention produces blazed gratings with low roughness, high line density, excellent pattern fidelity, consistent blaze angles, and high uniformity. This broadens the range of blazed grating fabrication methods while optimizing their performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0183] Figure 1 A schematic structural diagram of a preparation method provided in one embodiment of the present invention using ICP for pattern transfer;

[0184] Wherein, 10 is substrate, 20 is titanium dioxide optical film, 21 is titanium dioxide blazed grating, and 30 is mask layer;

[0185] Figure 2 A schematic structural diagram of a blazed grating provided in one embodiment of the present invention;

[0186] Figure 3 This is an AFM image of the titanium dioxide optical film obtained by the preparation method provided in Example 1;

[0187] Figure 4 A temperature curve diagram of the soft baking in step (4) of the preparation method provided in Example 1;

[0188] Figure 5 This is a SEM image of the base glue before modification in step (5) of the preparation method provided in Example 1;

[0189] Figure 6 This is a SEM image of the modified base glue in step (5) of the preparation method provided in Example 1;

[0190] Figure 7 An SEM image of a location of the blazed grating provided in Example 1;

[0191] Figure 8 This is an SEM image of another position of the blazed grating provided in Example 1;

[0192] Figure 9 This is an SEM image of another position of the blazed grating provided in Example 1;

[0193] Figure 10 This is an SEM image of the blazed grating provided in Example 3;

[0194] Figure 11 This is an SEM image of the blazed grating provided in Example 4;

[0195] Figure 12 This is an SEM image of the blazed grating provided in Example 5;

[0196] Figure 13 This is an SEM image of the blazed grating provided in Example 6;

[0197] Figure 14 This is an SEM image of the blazed grating provided in Example 7;

[0198] Figure 15 This is the SEM image of the blazed grating provided in Example 8. DETAILED DESCRIPTION

[0199] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0200] As used herein, the terms "comprises," "including," "having," "containing" or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a listed element is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0201] "Optionally," "optionally," or "either" means that the subsequently described matter or event can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0202] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e. the number of times they appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the quantity clearly refers to only the singular form.

[0203] In this article, the term "sccm" is the unit of gas flow, which stands for Standard Cubic Centimeter per Minute; the term "mtorr" is the unit of pressure, 1mtorr = 0.133Pa; since pressure and pressure are directly proportional when the force applied area is the same, pressure is used in this article.

[0204] In one embodiment, the method for preparing a blazed grating provided by the present invention comprises the following steps:

[0205] (1) preparing a titanium dioxide optical film on a substrate;

[0206] (2) coating an embossed adhesive layer on the titanium dioxide optical film, patterning the embossed adhesive layer by nanoimprinting, and then post-processing to form a mask layer to obtain a structure to be etched; the post-processing method is soft baking and / or UV curing;

[0207] (3) performing primer modification and pattern transfer on the structure to be etched by inductively coupled plasma etching (ICP) in sequence to obtain a titanium dioxide blazed grating; the processing gas for the pattern transfer includes a combination of a fluorine-based gas and HBr;

[0208] (4) Debonding the titanium dioxide blazed grating to obtain the blazed grating.

[0209] In one embodiment, the structural diagram of the preparation method using ICP for pattern transfer is as follows: Figure 1 As shown; wherein, 10 represents a substrate, 20 represents a titanium dioxide optical film, 21 represents a titanium dioxide blazed grating, and 30 represents a mask layer.

[0210] In a specific embodiment, the structural diagram of the blazed grating is as follows: Figure 2 As shown, Figure 2 Where d represents the grating period, γ represents the blaze angle, a represents the length of the blaze surface, m=0, m=1, and m=2 represent multiple levels of incident light and reflection, respectively, and i represents the incident angle.

[0211] The specific process steps of the method for preparing the blazed grating provided by the present invention will be described below in conjunction with multiple embodiments.

[0212] In the following examples, the substrate used is a high-refractive glass with a refractive index of 1.471, brand Borofloat 33, purchased from Green Crystal Glass; the embossing adhesive is brand Mr-NIL6000E, purchased from Yilan Microelectronics.

[0213] Example 1

[0214] A blazed grating and a method for preparing the same, the method comprising the following steps:

[0215] (1) Providing a substrate:

[0216] High-refractive glass was selected as the substrate, and an acidic oxidizing cleaning solution of H2SO4:HF:H2O2:H2O=10:15:10:60 was prepared. The substrate was cleaned in the acidic oxidizing cleaning solution at 90°C for 20 seconds to remove organic impurities on the surface; then the substrate was cleaned in deionized water for 30 seconds to rinse off the residual acidic oxidizing cleaning solution to obtain a cleaned substrate.

[0217] (2) Preparation of titanium dioxide optical film:

[0218] TiO2 optical thin film was prepared on the substrate by magnetron sputtering method. The target material was a cylindrical rotating target material. The process parameters were as follows: pressure of 13mtorr, power of 250W, RF voltage of 450V, temperature of 25℃, processing gas of Ar and O2, Ar flow rate of 45sccm, O2 flow rate of 3sccm, distance Z between target and substrate of 2.75mm, ion gun tilting angle (Guntilting) of 7°, rotation angle of 12°, time of 1560s, and a titanium dioxide optical thin film with a thickness of 160nm was obtained.

[0219] The surface morphology and roughness of the titanium dioxide optical film prepared in this embodiment were tested using an atomic force microscope (AFM, model Nanusurf C3000, Nansurf Flex-Mount, Switzerland). The AFM images obtained are as follows: Figure 3As shown in FIG, according to the AFM test results, the roughness of the titanium dioxide optical film is 0.231 nm.

[0220] (3) Preparation of embossed adhesive layer:

[0221] The embossed adhesive layer was prepared on the titanium dioxide optical film by spin coating. The process parameters were as follows: the glue dripping rate was 2.5 mL / s, the turntable speed was 3500 rpm, the acceleration was 800 rpm / s, and the time was 60 s, and the embossed adhesive layer with a thickness of 240 nm was obtained.

[0222] (4) Preparation of mask layer:

[0223] The imprinted adhesive layer is nano-imprinted using a predetermined nano-imprint master to achieve patterning. The patterned imprinted adhesive layer is soft-baked to enhance the anti-etching effect on the top. The temperature curve of the soft-baking is shown in FIG. Figure 4 As shown in FIG, the specific process is as follows: the patterned sample is placed in a soft oven, evacuated to 400 mtorr, and a heating program is set to increase the temperature from 25°C to 90°C within 30 seconds, and then kept warm for 15 seconds to allow the moisture in the imprint glue to gradually evaporate. The temperature is continued to be increased from 90°C to 120°C within 30 seconds, and the ejector pin is started to drop so that the substrate can directly contact the hot plate. During the early heating process, a large amount of solvent is evaporated to avoid uneven evaporation of moisture in the imprint glue due to rapid heating, which affects the subsequent etching effect. The temperature is kept at 120°C for 60 seconds to complete the soft baking, form a mask layer, and obtain the structure to be etched.

[0224] (5) Primer modification:

[0225] Inductively coupled plasma etching (ICP) technology is used to modify the primer of the etched structure. The specific process parameters are as follows: the process chamber pressure is set to 10mtorr, the source power is 600W, the bias power is 10% of the source power, the processing gases are CHF3 and CF4, the flow rate of CHF3 is 60sccm, the flow rate of CF4 is 20sccm, and the ICP etching time is 50s to complete the primer modification.

[0226] Scanning electron microscope (SEM, model SU4700, Hitachi Electronics) was used to test the morphology of the samples before and after primer modification. The SEM images before and after primer modification are shown in Figure 2. Figure 5 and Figure 6 As shown in the figure, it can be seen from the comparison that the primer modification can remove 50nm of residual primer, so that the residual primer is less than 5% of the grating height, which has the least impact on the subsequent etching morphology.

[0227] (6) Graphic transfer:

[0228] The ICP technology is used to transfer the pattern of the mask layer to the titanium dioxide optical film. The structural diagram of the pattern transfer is shown in the figure. Figure 1 As shown, the specific process parameters are as follows: set the process chamber pressure to 10mtorr, the chamber temperature to 60℃, the source power to 400W, the bias power to 75W, the processing gases to CHF3, CF4 and HBr, the flow rate of CHF3 to 50sccm, the flow rate of CF4 to 10sccm, and the flow rate of HBr to 50sccm; the ICP etching time to 140s, and a titanium dioxide blazed grating was obtained.

[0229] (7) Glue removal:

[0230] The titanium dioxide blazed grating obtained after pattern transfer was stripped. Dry stripping was first performed using the following method: the sample was transferred to a stripping chamber via a robotic arm. The temperature was set to 250°C. The first stripping process consisted of O2 and CF4 at a flow rate of 2500sccm for O2 and 20sccm for CF4 at a power of 900W. The first stripping process lasted for 3 minutes to remove the mask imprint adhesive. A second stripping process was then performed using O2 and a N2 / H2 mixture (with a 96:4 ratio of N2 to H2) at a flow rate of 1000sccm for O2 and 600sccm for a 96% N2 / 4% H2 mixture at a power of 900W. The second stripping process lasted for 2 minutes to fully react with the residual adhesive. After the dry stripping process, wet stripping was performed using an organic solvent (a mixture of acetone and ethylene glycol in a ratio of 3:7) for rinsing to complete the stripping process and obtain the blazed grating.

[0231] The morphology of the blazed grating prepared in this embodiment was characterized by scanning electron microscopy. The edge position, middle position and center position of the blazed grating were tested respectively. The SEM images obtained are as follows: Figure 7 、 Figure 8 and Figure 9 As shown, combined with the SEM test results, it can be seen that the height of the TiO2 blazed grating is close to 172nm, the blaze angle is close to 86°, the morphology of the blazed grating has excellent uniformity, good consistency of the blaze angle, and high graphic fidelity.

[0232] Example 2

[0233] A blazed grating and a method for preparing the same, the method comprising the following steps:

[0234] (1) Providing a substrate:

[0235] High-refractive glass was selected as the substrate, and an acidic oxidizing cleaning solution of H2SO4:HF:H2O2:H2O=10:15:10:60 was prepared. The substrate was cleaned in the acidic oxidizing cleaning solution at 90°C for 15 seconds to remove organic impurities on the surface; then the substrate was cleaned in deionized water for 30 seconds to rinse off the residual acidic oxidizing cleaning solution to obtain a cleaned substrate.

[0236] (2) Preparation of titanium dioxide optical film:

[0237] TiO2 optical thin film was prepared on the substrate by ion beam deposition (IBD) method, and the process parameters were as follows: the parameters of the deposition beam were: beam voltage of 1120V, beam current of 380mA, ignition RF power of 350W, suppressor voltage of 180V, the processing gas of the deposition beam was Xe, and the flow rate was 5sccm; the parameters of the auxiliary beam were: beam voltage of 50V, beam curent of 450mA, ignition RF power of 350W, suppressor voltage of 800V, the processing gases of the auxiliary beam were O2 and Ar, the flow rate of O2 was 20sccm, the flow rate of Ar was 5sccm, the Ti target angle was 55, the IBD deposition time was 1800s, and a titanium dioxide optical thin film with a thickness of 165nm was obtained.

[0238] (3) Preparation of embossed adhesive layer:

[0239] The embossed adhesive layer was prepared on the titanium dioxide optical film by spin coating. The process parameters were as follows: the glue dripping rate was 2.5 mL / s, the turntable speed was 3500 rpm, the acceleration was 800 rpm / s, and the time was 60 s, and the embossed adhesive layer with a thickness of 240 nm was obtained.

[0240] (4) Preparation of mask layer:

[0241] The imprint adhesive layer is nanoimprinted using a pre-defined nanoimprint master to achieve patterning. The patterned imprint adhesive layer is then ultraviolet (UV) cured to further solidify the adhesive. The specific UV curing process is as follows: the curing temperature is set to 110°C, the time is 5 seconds, and the UV lamp mode is set to flash mode; then the temperature is set to 200°C, the time is 3 seconds, and the UV lamp mode is selected to low; then the UV lamp mode is adjusted to high for 12 seconds. In high power mode, the polymer in the imprint adhesive undergoes a cross-linking reaction, enhancing its etching resistance; finally, the temperature heater is turned off, and the film is removed after standing for 15 seconds to complete UV curing, forming a mask layer and obtaining the structure to be etched.

[0242] (5) Primer modification:

[0243] ICP technology is used to modify the bottom glue of the etched structure. The specific process parameters are as follows: set the process chamber pressure to 12mtorr, the source power (Source power) to 650W, the bias power (bias power) to 10% of the source power, the processing gas is CHF3 and CF4, the flow rate of CHF3 is 70sccm, the flow rate of CF4 is 20sccm, and the ICP etching time is 45s. 53nm of residual glue can be removed to complete the bottom glue modification.

[0244] (6) Graphic transfer:

[0245] The ICP technology is used to transfer the pattern of the mask layer to the titanium dioxide optical film. The structural diagram of the pattern transfer is shown in the figure. Figure 1 As shown, the specific process parameters are as follows: set the process chamber pressure to 10mtorr, the source power (Source power) to 450W, the bias power (bias power) to 60W, the processing gases are CHF3, CF4 and HBr, the flow rate of CHF3 is 60sccm, the flow rate of CF4 is 15sccm, and the flow rate of HBr is 40sccm; the ICP etching time is 130s, and a titanium dioxide blazed grating is obtained.

[0246] (7) Glue removal:

[0247] The titanium dioxide blazed grating obtained after pattern transfer was stripped. Dry stripping was first performed using the following method: the sample was transferred to a stripping chamber via a robotic arm. The temperature was set to 250°C. The first stripping process involved O2 and CF4, with an O2 flow rate of 2500sccm and a CF4 flow rate of 20sccm. The power was 900W, and the first stripping process lasted for 3 minutes to remove the mask imprint adhesive. A second stripping process was then performed using O2 and a N2 / H2 mixture with an O2 flow rate of 1000sccm and a 96% N2 / 4% H2 mixture with a flow rate of 600sccm. The power was 900W, and the second stripping process lasted for 2 minutes to fully react with the residual adhesive. After the dry stripping process was completed, wet stripping was performed using an organic solvent (a mixture of acetone and ethylene glycol in a volume ratio of 3:7) for rinsing to complete the stripping process and obtain the blazed grating.

[0248] Example 3

[0249] A blazed grating and a preparation method thereof, wherein the preparation method differs from that of Example 1 only in that the ICP processing gases in step (6) are CHF3, CF4, and HBr, the flow rate of CHF3 is 50 sccm, the flow rate of CF4 is 10 sccm, the flow rate of HBr is 75 sccm, and the ratio of fluorine-based gas to auxiliary gas HBr is 1:1.25; the other process steps and parameters are the same as those of Example 1, and a blazed grating is obtained.

[0250] The SEM image of the blazed grating prepared in Example 3 is as follows: Figure 10 As shown, compared with Example 1, the flow ratio of the fluorine-based gases CHF3 and CF4 in the processing gas of the graphic transfer ICP of Example 3 is 4:1, and the flow rate of HBr is increased from 50 sccm to 75 sccm; in addition, the imprint glue is soft-baked and cured after nanoimprinting, and a small amount of HBr is added to protect the glue, which has little effect on the morphology of the blazed surface. The blazed grating provided by Example 3 has excellent morphological uniformity.

[0251] Example 4

[0252] A blazed grating and a preparation method thereof, wherein the preparation method differs from that of Example 1 only in that the ICP processing gases in step (6) are CHF3, CF4, and HBr, the flow rate of CHF3 is 60 sccm, the flow rate of CF4 is 20 sccm, the flow rate of HBr is 50 sccm, and the ratio of fluorine-based gas to auxiliary gas HBr is 1:0.625; the other process steps and parameters are the same as those of Example 1, and a blazed grating is obtained.

[0253] The SEM image of the blazed grating prepared in Example 4 is as follows: Figure 11As shown, compared with Example 1, the flow ratio of the fluorine-based gases CHF3 and CF4 in the ICP processing gas in the graphic transfer of Example 4 is 3:1. Since CF4 is easier to dissociate into more fluorine to react with TiO2, the fluorine-based gas reacts faster with the blazed surface of the blazed grating during the graphic transfer process, and the protection is a bit weak, resulting in a slightly concave slope of the etched morphology.

[0254] Example 5

[0255] A blazed grating and a preparation method thereof, wherein the preparation method differs from that of Example 1 only in that the ICP processing gases in step (6) are CHF3, CF4, and HBr, the flow rate of CHF3 is 50 sccm, the flow rate of CF4 is 50 sccm, and the flow rate of HBr is 50 sccm; the other process steps and parameters are the same as those of Example 1, and a blazed grating is obtained.

[0256] The SEM image of the blazed grating prepared in Example 5 is as follows: Figure 12 As shown, in the graphic transfer of Example 5, the flow ratio of fluorine-based gases CHF3 and CF4 in the ICP processing gas is 1:1, and the proportion of CF4 increases, resulting in excessively fast etching and insufficient protection of the blazing surface, affecting the fidelity of the graphic and the accuracy of the blazing angle.

[0257] Example 6

[0258] A blazed grating and a preparation method thereof, wherein the preparation method differs from Example 1 only in that no soft baking treatment is performed, i.e., patterning is achieved by nanoimprinting, and the formed mask layer directly enters the primer modification step of step (5); the other process steps and parameters are the same as those of Example 1, and a blazed grating is obtained.

[0259] The SEM image of the blazed grating prepared in Example 6 is as follows: Figure 13 As shown in FIG. 1 , due to the lack of a soft-baking step, the imprinted adhesive does not have a certain etching resistance, and the pattern is distorted after the primer modification and pattern transfer.

[0260] Example 7

[0261] A blazed grating and a method for preparing the same. The preparation method differs from Example 1 only in that no primer modification step is performed, i.e., the structure to be etched in the mask layer formed in step (4) is directly subjected to pattern transfer; the other process steps and parameters are the same as those in Example 1, to obtain a blazed grating.

[0262] The SEM image of the blazed grating prepared in Example 7 is as follows: Figure 14 As shown, since the base glue has not been modified, the blaze angle position participates in the chemical reaction faster, and other areas are protected by the glue, resulting in the blaze angle position of some graphics having the defect of being hollowed out.

[0263] Example 8

[0264] A blazed grating and a method for preparing the same. The preparation method differs from that of Example 1 only in that the ICP processing gas in step (6) does not contain HBr but only contains CHF3 and CF4, the flow rate of CHF3 is 50 sccm, and the flow rate of CF4 is 10 sccm; the other process steps and parameters are the same as those of Example 1, and a blazed grating is obtained.

[0265] The SEM image of the blazed grating prepared in Example 8 is as follows: Figure 15 As shown, in the pattern transfer of Example 8, the ICP processing gas does not contain HBr, which reduces the protection of the blazing surface and the anti-blazing surface, resulting in low fidelity of the pattern and failure to obtain a blazing angle that meets the precision requirements.

[0266] The applicant states that while the present invention uses the aforementioned embodiments to illustrate the blazed grating and its fabrication method, the present invention is not limited to the aforementioned process steps, nor does it necessarily rely on the aforementioned process steps for implementation. Persons skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a blazed grating, characterized in that: The preparation method comprises: Depositing a titanium dioxide optical film with uniform thickness on a target substrate; Spin-coating an embossing adhesive on the titanium dioxide optical film by a coating process; Imprinting the imprint adhesive to perform patterning to form a mask layer; Selecting inductively coupled plasma etching parameters that match the target substrate for etching the titanium dioxide optical thin film; wherein the inductively coupled plasma etching parameters are used to etch the titanium dioxide optical thin film on the target substrate through an etching process to obtain a corresponding blazed grating; Based on the inductively coupled plasma etching parameters, a corresponding inductively coupled plasma etching process is used to transfer the nanoimprinted pattern, thereby etching the titanium dioxide optical film on the target substrate to obtain the corresponding blazed grating; The etching selection ratio between the material of the mask layer and the TiO2 optical film is 1:1, thereby achieving precise control of the blaze angle.

2. The preparation method according to claim 1, characterized in that Before depositing a titanium dioxide optical film of uniform thickness on a target substrate, the following steps are also included: Select a prefabricated substrate; removing organic impurities from the prefabricated substrate by a strong oxidizing water washing solution; The residual acid on the prefabricated substrate is rinsed clean with a deionized water solution to form a target substrate.

3. The preparation method according to claim 2, characterized in that Removing organic impurities from the prefabricated substrate by a strong oxidizing water washing solution, comprising: A strong oxidizing aqueous solution of the following composition: H2SO4:HF:H2O2:H2O=X:15:Y:60 is heated to 80-100°C to clean the prefabricated substrate for 15-20 seconds, wherein X is 5-30 and Y is 5-30.

4. The preparation method according to claim 1, characterized in that Depositing a uniform thickness of titanium dioxide optical thin film on a target substrate, including: Titanium dioxide optical thin film is sputtered by magnetron sputtering. The target material is a cylindrical rotating target material. The process parameters are as follows: pressure is 5-100 mtorr, power is 200-300 W, temperature is 20-30℃, RF voltage is 400-500 V, Ar flow rate is 30-60 sccm, O2 flow rate is 1-5 sccm, the distance between the target and the substrate is 2-5 mm, the ion gun tilt angle is 3-10°, the target pole shoe rotation angle is 5-30 ° / min, the time is 10-40 min, and the thickness of the titanium dioxide optical film is 100-200 nm.

5. The preparation method according to claim 1, characterized in that Titanium dioxide optical thin films were deposited by ion beam deposition. The process parameters of the deposition beam were as follows: beam voltage of 800-1500 V, beam current of 100-500 mA, ignition RF power of 200-500 W, suppressor voltage of 50-200 V, and Xe flow rate of 1-10 sccm; the process parameters of the auxiliary beam were as follows: beam voltage of 20-100 V, beam current of 300-500 mA, ignition RF power of 300-500 W, suppressor voltage of 200-800 V, O2 flow rate of 5-50 sccm, Ar flow rate of 1-10 sccm, Ti incident angle of 30-60°, and ion beam deposition time of 10-60 min. The deposition speed was controlled by adjusting the power and O2 flow rate in the auxiliary beam.

6. The preparation method according to claim 1, characterized in that Spin-coating an embossing adhesive on the titanium dioxide optical film by a coating process, comprising: The spin coating process was set with the following operating parameters: the dispensing rate was 1–5 mL / s, the turntable speed was set to 1000–6000 rpm, the acceleration was set to 200–1000 rpm / s, and the time was set to 20–90 s; Based on the working parameters, a embossing adhesive is spin-coated on the titanium dioxide optical film through a coating process.

7. The preparation method according to claim 1, characterized in that After spin-coating the embossing adhesive on the titanium dioxide optical film through a coating process, the method comprises: placing the target substrate with the imprint glue in a soft oven, wherein the soft oven has a heating plate, and the target substrate is not in contact with the heating plate; Evacuate the soft oven to 5-500 mtorr; According to the heating process, the temperature of the soft oven is raised from 25°C to 80-100°C within 30 seconds, and then kept warm for 10-20 seconds to allow the moisture in the imprinting glue to gradually evaporate; The temperature of the soft oven was raised from 90°C to 110-130°C within 30 s, and the target substrate was directly contacted with the hot plate.

8. The preparation method according to claim 1, characterized in that After spin-coating the embossing adhesive on the titanium dioxide optical film through a coating process, the method comprises: The parameters of the UV lamp curing process are set as follows: first, set the curing temperature to 100-120°C, the time to 1-10 s, and the UV lamp mode to flash mode, then set the temperature to 180-220°C, the time to 1-5 s, the UV lamp mode to low power mode, and then adjust the UV lamp mode to high power mode. In high power mode, the polymer in the imprint glue is cross-linked to enhance its etching resistance; finally, turn off the temperature heater, let it stand for 10-20 s, and then take it out.

9. The preparation method according to claim 1, characterized in that After the imprinting glue is patterned, it also includes: The imprint glue on the target substrate after patterning is modified so that the residual amount of the primer on the target substrate is less than 5% of the grating height.

10. The preparation method according to claim 9, characterized in that Modify the imprint glue on the target substrate after patterning. The parameters are set as follows: The pressure is 5-100 mtorr, the source power is 400-700 W, the bias power is 5%-15% of the source power, the flow ratio of CHF3 to CF4 in the process gas is (2.5-3.5):1, the flow rate of CHF3 is 10-100 sccm, the flow rate of CF4 is 5-40 sccm, and the etching time is 5-100 s.

11. The preparation method according to claim 1, characterized in that Select inductively coupled plasma etching parameters that match the target substrate for etching titanium dioxide optical thin films, including: The chamber temperature of the inductively coupled plasma etching is 20-100° C., the chamber pressure is 5-100 mtorr, the etching gas includes a fluorine-based gas and HBr, the fluorine-based gas is CHF3 and CF4, the flow ratio of CHF3 to CF4 is (3-5):1, the flow rate of CF4 is 1-200 sccm, the flow rate of CHF3 is 10-200 sccm, the flow ratio of the fluorine-based gas to HBr is 1:(0.5-1.35), the flow rate of HBr is 10-300 sccm, the source power is 100-1000 W, the bias power is 10-30% of the source power, the bias power is 0-200 W, and the etching time is 60-180 s; Measure the grating topography at different positions to determine etching uniformity, grating height, blaze angle and anti-blaze angle; When the etching uniformity, grating height, blaze angle and anti-blaze angle meet the conditions, it is determined that the corresponding blazed grating is etched on the target substrate.

12. The preparation method according to claim 1, characterized in that The preparation method further comprises: removing the mask glue on the blazed grating by dry glue removal; The residual glue on the blazed grating is removed by wet debonding.

13. The preparation method according to claim 12, characterized in that The dry stripping method is used to remove the mask glue on the blazed grating, comprising: The blazed grating is transferred to a debonding process chamber by a robotic arm. The temperature of the debonding process chamber is set at 20-300°C. First, the mask adhesive is removed by introducing process gases with a flow rate of 1000-5000 sccm of O2, a flow rate of 0-50 sccm of CF4, and a flow rate of 100-1000 sccm of N2 / H2 mixed gas or N2. The process debonding time is set. Then set the flow rate of the process gas N2 / H2 mixed gas into the debonding process chamber to 100-1000 sccm, the flow rate of O2 to 1000-5000 sccm, the power to 500-1500 W, and the debonding process to remove the residual glue for 1-5 minutes; The step of removing residual adhesive on the blazed grating by wet debonding comprises: The TiO2 surface was rinsed with an organic solution.

14. A blazed grating, characterized in that: The blazed grating is prepared by the preparation method according to any one of claims 1 to 13.

15. A semiconductor working device, characterized in that: The working device prepares the blazed grating by the preparation method according to any one of claims 1 to 13.

16. The working device according to claim 15, characterized in that: The working device at least includes an inductively coupled plasma etcher, a coating device and an imprinting device.

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