A method for preparing a titanium dioxide grating and a titanium dioxide grating

Abstract

The application provides a preparation method of a titanium dioxide grating and the titanium dioxide grating, and the method comprises the following steps: (1) a pretreatment process: pre-cleaning a treatment chamber; (2) an initialization process: placing titanium dioxide to be etched on an electrostatic chuck in the treatment chamber, and the temperature of the electrostatic chuck is a preset value; (3) a preparation process: obtaining a target titanium dioxide grating through at least two preparation processes, and the preparation parameters in the preparation processes are determined according to a preparation target corresponding to the target titanium dioxide grating, and the preparation target comprises at least one of a target height, a target width and a target angle. According to the application, the target titanium dioxide grating can be prepared according to the preparation target through a simple process flow.

Description

Technical Field

[0001] This invention relates to the field of titanium dioxide grating manufacturing, and specifically to a method for preparing a titanium dioxide grating and the titanium dioxide grating itself. Background Technology

[0002] Titanium dioxide gratings are common micro-optical components. By designing titanium dioxide gratings, incident light can be modulated through diffusion, beam shaping, light distribution, and optical focusing, thereby achieving many special functions that are difficult to achieve with traditional optical components. Titanium dioxide grating elements have wide applications in imaging sensing, lighting, displays, photovoltaics, and other fields.

[0003] The optical properties of titanium dioxide gratings (such as focal length, aberrations, and light field distribution) are directly related to their geometry (curvature, height, surface roughness, etc.) and material properties (refractive index). Any deviation in size or shape will lead to significant changes in optical performance, thereby affecting the function of the entire optical system. How to fabricate high-precision titanium dioxide gratings is a problem that urgently needs to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing titanium dioxide gratings and a titanium dioxide grating. This invention can prepare high-precision titanium dioxide gratings through a simple process.

[0005] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, this application provides a method for preparing a titanium dioxide grating, the method comprising the following steps: (1) Pretreatment process: pre-cleaning the chamber; (2) Initialization process: Place the titanium dioxide to be etched onto the electrostatic chuck in the processing chamber. The temperature of the electrostatic chuck is a preset value. (3) Preparation process: The target titanium dioxide grating is obtained through at least two preparation processes. The preparation parameters in the preparation process are determined according to the preparation target corresponding to the target titanium dioxide grating. The preparation target includes at least one of the target height, target width and target angle.

[0006] Preferably, the target titanium dioxide grating includes at least one step, and the fabrication target corresponds to all or part of the steps.

[0007] Preferably, the preparation process includes a preliminary preparation process and a main preparation process, wherein the preliminary preparation process is used to produce a rough titanium dioxide grating, and the main preparation process is used to produce a refined titanium dioxide grating.

[0008] Preferably, each step of the preparation process includes a resist removal process and an etching process; wherein: The adhesive removal process is used to remove the imprint adhesive from the surface of the titanium dioxide to be etched; The etching process is used to etch the titanium dioxide to be etched according to the preparation target.

[0009] Preferably, the pressure value during the preparation process is 10~60mT.

[0010] Preferably, the radio frequency parameter value in the preparation process is 20~30W.

[0011] Preferably, in step (2), the temperature of the electrostatic chuck is 70~90℃.

[0012] Secondly, this application provides a titanium dioxide grating, which is prepared by the method for preparing the titanium dioxide grating described in the first aspect above.

[0013] Thirdly, this application provides a semiconductor processing apparatus for performing the method for fabricating a titanium dioxide grating as described in the first aspect.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: This invention requires only simple process steps in the fabrication of titanium dioxide gratings. High-precision titanium dioxide gratings can be fabricated through at least two steps. These at least two steps allow for precise control of one or more of the target titanium dioxide grating's height, width, and angle, based on the desired fabrication objective. The titanium dioxide grating fabrication method provided in this application balances the complexity and fidelity of the manufacturing process, thereby improving the fabrication efficiency of titanium dioxide gratings. Attached Figure Description

[0015] Figure 1 This is a flowchart of a method for fabricating a titanium dioxide grating provided in an embodiment of this application.

[0016] Figure 2 This is the morphology of the titanium dioxide grating before etching, as shown under a scanning electron microscope.

[0017] Figure 3 This is the morphology of the titanium dioxide grating after etching under a scanning electron microscope. Detailed Implementation

[0018] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0019] Figure 1A flowchart illustrating a method for fabricating a titanium dioxide grating according to an embodiment of this application is shown. The method includes the following steps: (1) Pretreatment process: pre-cleaning the chamber; (2) Initialization process: Place the titanium dioxide to be etched onto the electrostatic chuck in the processing chamber. The temperature of the electrostatic chuck is a preset value. (3) Etching process: The target titanium dioxide grating is obtained through at least two preparation steps. The preparation parameters in the preparation process are determined according to the preparation target corresponding to the target titanium dioxide grating. The preparation target includes at least one of the target height, target width and target angle.

[0020] Regarding the preprocessing process:

[0021] In some embodiments, the preprocessing process includes the following sub-steps: Sub-step 1: Pre-cleaning (Clean), using pre-cleaning gas to clean the processing chamber; Preferably, the pre-cleaning gas includes SF6 and / or O2.

[0022] In some embodiments, the pre-cleaning time is 1 to 5 minutes.

[0023] In some embodiments, the SF6 flow rate is 20~100 sccm.

[0024] In some embodiments, the O2 flow rate is 20~100 sccm.

[0025] Sub-step 2: Warm-up (Season); Preferably, the warm-up time is 10 to 30 minutes.

[0026] Sub-step 3: Cleaning, using cleaning gas to clean the processing chamber; Preferably, the clean gas includes SF6 and / or O2.

[0027] In some embodiments, the cleaning time is 5 to 10 minutes.

[0028] In some embodiments, the SF6 flow rate is 20~100 Sccm.

[0029] In some embodiments, the O2 flow rate is 20~100 sccm.

[0030] Repeated cleaning of the chamber helps ensure etching accuracy.

[0031] Optionally, in this embodiment, the processing equipment used to fabricate the target titanium dioxide grating is an inductively coupled plasma (ICP) etching machine. The processing chamber is an etching chamber.

[0032] Regarding the initialization process:

[0033] In some embodiments, the processing chamber includes an electrostatic chuck.

[0034] In some embodiments, the temperature of the electrostatic chuck is 70~90°C. Preferably, the temperature of the electrostatic chuck is set to 70°C. In this embodiment, optionally increasing the temperature of the electrostatic chuck can help accelerate the chemical reaction rate within the processing chamber. However, excessively high temperatures can cause the gel to stick. Therefore, controlling the temperature of the electrostatic chuck helps to balance reaction efficiency and success rate while avoiding gel sticking.

[0035] During initialization, the titanium dioxide to be etched is placed on an electrostatic chuck, with the chuck at a preset temperature. Alternatively, this can be understood as placing the titanium dioxide to be etched on the electrostatic chuck at a preset temperature.

[0036] Regarding the preparation process:

[0037] In some embodiments, the preparation process involves at least two steps. The preparation parameters are determined based on the preparation target corresponding to the target titanium dioxide grating. Optionally, the preparation parameters include reaction time, gas flow rate, radio frequency parameters, etc. In some embodiments, the fabrication process varies depending on the specific fabrication objective of the titanium dioxide grating. For example, each fabrication objective corresponds to a specific fabrication process, or it can be understood as a one-to-one relationship between the fabrication objective and the fabrication process. For instance, if the fabrication objective is objective 1, the fabrication process corresponds to process 1; if the fabrication objective is objective 2, the fabrication process corresponds to process 2.

[0038] In some embodiments, multiple different preparation targets correspond to the same preparation process, or it can be understood that the preparation target and the preparation process are many-to-one. For example, when the preparation target is target 1, the preparation process corresponds to process 1; when the preparation target is target 2, the preparation process also corresponds to process 1.

[0039] In some embodiments, one preparation target can correspond to multiple different preparation processes, or it can be understood that the preparation target and the preparation process are one-to-many. For example, when the preparation target is target 1, the preparation processes can optionally correspond to process 1 and process 2.

[0040] In some embodiments, the target preparation includes at least one of target height, target width, and target angle. In this application embodiment, the target titanium dioxide grating is in the form of a conical stepped structure. For example, as shown... Figure 3 As shown, the target titanium dioxide grating includes at least one step. Optionally, the target is fabricated to correspond to all or part of the steps.

[0041] The fabrication target corresponds to all steps, which can also be understood as: each step in the target titanium dioxide grating corresponds to a fabrication target. For example, assuming the target titanium dioxide grating includes 3 steps {step 1, step 2, step 3}, then the optional fabrication targets include {fabrication target 1 corresponding to step 1, fabrication target 2 corresponding to step 2, and fabrication target 3 corresponding to step 3}.

[0042] The fabrication target corresponding to a certain step can also be understood as: some steps in the target titanium dioxide grating correspond to a fabrication target, while some steps do not. For example, assuming the target titanium dioxide grating includes 3 steps {step 1, step 2, step 3}, then optionally: the fabrication target includes {fabrication target 1 corresponding to step 1}, while {step 2, step 3} do not include a fabrication target.

[0043] In some embodiments, the pressure during the preparation process is 10~60 mT. In this embodiment, a low-pressure environment is used for preparation because, from the perspective of plasma physics, the mean free path of gas molecules becomes longer under low pressure, thus allowing ions to maintain a straight trajectory under the influence of an electric field.

[0044] In some embodiments, the radio frequency parameters during the fabrication process are 20-30 W. From a process perspective, while a low-voltage environment can extend the mean free path of ions, excessively high bias voltage can lead to excessive ion energy and damage. Therefore, low voltage combined with low bias voltage can achieve three key effects: first, it maintains perpendicular ion incidence and avoids step tilting; second, it suppresses the channeling effect and prevents micro-grooves from forming in single-crystal TiO2; and third, it controls redeposition.

[0045] In some embodiments, the fabrication process includes a preliminary fabrication step and a main fabrication step. The preliminary fabrication step is used to produce a rough titanium dioxide grating, while the main fabrication step is used to produce a refined titanium dioxide grating. By fabricating the titanium dioxide grating step by step, from rough to fine, it is beneficial to achieve the fabrication of a target titanium dioxide grating with higher precision.

[0046] In some embodiments, the number of fabrication steps is related to the fabrication objective. For example, the number of fabrication steps is proportional to the fabrication objective. Each fabrication step includes a resist removal step and an etching step. The resist removal step is used to remove the imprinting adhesive from the surface of the titanium dioxide to be etched, and the etching step is used to etch the titanium dioxide to be etched according to the fabrication objective.

[0047] Initial preparation process: In some embodiments, the initial preparation process includes a resist removal process and an etching process.

[0048] In some embodiments, the stripping gas includes O2 and / or CF4. The initial stripping process is used to remove the primer from the titanium dioxide to be etched. The flow rate of the stripping gas is 10~120 sccm.

[0049] In some embodiments, the etching gas includes one or more of C4F8, Cl2, SF6, CF4, CHF3, and HBr. The flow rate of the etching gas is 10-120 sccm. The initial etching pass is used to etch a portion of the titanium dioxide on the titanium dioxide to be etched, thereby obtaining a rough titanium dioxide grating. In some embodiments, the initial etching pass is prepared at least once. Repeated preparation of the initial pass facilitates high-precision, low-damage pattern transfer.

[0050] Main preparation process: In some embodiments, the main preparation process is cycled at least once.

[0051] In some embodiments, the fabrication process includes a resist removal process and an etching process.

[0052] In some embodiments, the stripping gas includes O2 and / or CF4. The main stripping process is used to laterally remove the imprinting adhesive from the titanium dioxide to be etched, thereby controlling the step width. The flow rate of the stripping gas is 10~120 sccm.

[0053] In some embodiments, if a target width exists in the fabrication target, then at least one stripping master process needs to be executed. Alternatively, this can be understood as the stripping master process being used to control the step width based on the target width.

[0054] The target width is related to the flow rate of the de-adhesive gas and the de-adhesive time. For example, the target width is directly proportional to the flow rate of the de-adhesive gas. The larger the target width, the larger the flow rate of the de-adhesive gas required; the smaller the target width, the smaller the flow rate of the de-adhesive gas required. Similarly, the target width is directly proportional to the de-adhesive time. The larger the target width, the longer the de-adhesive time; the smaller the target width, the shorter the de-adhesive time.

[0055] In some embodiments, the etching gas includes one or more of C4F8, Cl2, SF6, CF4, CHF3, and HBr. The flow rate of the etching gas is 10~120 sccm. The main etching process is used to etch a portion of the titanium dioxide on the titanium dioxide to be etched, and the step height and angle are controlled during this process.

[0056] In some embodiments, if the target has a target height and / or target angle, then at least one etching main process needs to be performed.

[0057] The target height is related to the flow rate of the etching gas and the etching time. For example, the target height is directly proportional to the flow rate of the etching gas. The higher the target height, the greater the flow rate of the etching gas required; the smaller the target height, the smaller the flow rate of the etching gas required. Similarly, the target height is directly proportional to the etching time. The higher the target height, the longer the etching time; the smaller the target height, the shorter the etching time.

[0058] The target angle is related to the ratio of etching gases. For example, when the target angle is 85°~90°, 30 sccm of C4F8 and 60 sccm of Cl2 are introduced, meaning the ratio of etching gases is 2:1. In the embodiments of this application, since there are many types of etching gases, different combinations of etching gases may be used in different production and experimental processes. Therefore, the ratio of etching gases used may vary for different target angles, which will not be elaborated further here.

[0059] In some embodiments, the process of fabricating the target titanium dioxide grating employs... It should be noted that "sccm" is a unit of gas mass flow rate, and sccm (Standard Cubic Centimeter per Minute) means standard milliliters per minute; mT is a unit of pressure, and mT represents the pressure in micrometers of mercury, which is one-thousandth of the pressure in millimeters of mercury. 1 mT equals 0.133 Pa.

[0060] Example 1 (Target height: 100nm; Target width: 300nm; Target angle: 90°) This embodiment provides a method for preparing a titanium dioxide grating, the method comprising the following steps: (1) Pre-cleaning: Treat the chamber with 50 sccm SF6 + 20 sccm O2 for 3 minutes; (2) Warm-up (Season), warm up for 10 minutes; (3) Cleaning: Clean the chamber with 50 sccm SF6 + 20 sccm O2 for 3 minutes; (4) Initialization: Place the titanium dioxide to be etched onto the electrostatic chuck in the processing chamber and set the temperature of the electrostatic chuck to 70°C. (5) Initial process for removing adhesive: Use 80sccmO2 + 20sccmCF4 to remove the base adhesive; In this embodiment, the initial resist removal time is determined based on the initial thickness of the base resist and the resist removal capacity of the processing equipment. The resist removal time is designed to avoid excessive removal of the base resist. For example, assuming the base resist on the titanium dioxide surface to be etched is 50 nm, the resist removal time should be determined in conjunction with the resist removal capacity of the processing equipment. In principle, all the base resist on the titanium dioxide surface should be removed within the resist removal time, and the thickness of the removed base resist should be as close to 50 nm as possible, but less than or equal to 50 nm.

[0061] For example, such as Figure 2 As shown, the initial thickness of the base adhesive is 30nm, and the adhesive removal time for the initial process is set to 10s.

[0062] (6) Initial etching process: use 30 sccm C4F8 + 60 sccm Cl2 to etch the titanium dioxide to be etched; In this embodiment, the etching time corresponding to the initial etching process is determined based on the size of the titanium dioxide to be etched and the etching capacity of the processing equipment. The etching time is based on the principle of not causing over-etching of the titanium dioxide, and is limited by the preparation target. For example, assuming the width of the titanium dioxide to be etched is 300 nm, and the target width in the preparation target is 200 nm, then the etching time should be determined in conjunction with the etching energy of the processing equipment. In principle, the titanium dioxide should be etched to a width of 100 nm (300 nm - 200 nm) within the etching time, and the width of the etched titanium dioxide should be as close to 100 nm as possible, but less than or equal to 100 nm.

[0063] (7) Main process for degumming; In this embodiment, the adhesive removal time for the main adhesive removal process is determined based on the initial thickness of the printing adhesive and the adhesive removal capacity of the processing machine. The adhesive removal time is designed to avoid excessive removal of the printing adhesive. The operation of the main adhesive removal process is essentially the same as that of the initial adhesive removal process.

[0064] (8) Etching main process: use 30sccmC4F8+60sccmCl2 to etch the titanium dioxide to be etched.

[0065] In this embodiment, the etching time corresponding to the main etching process is determined based on the size of the titanium dioxide to be etched and the etching capacity of the processing equipment. The etching time is designed to avoid over-etching of the titanium dioxide and is limited by the preparation target. The operation of the main etching process is basically the same as that of the initial etching process.

[0066] For example, such as Figure 2 and Figure 3 As shown in the comparison, for the lowest step, based on Figure 2 In the initial state shown, with the target dimensions including a height of 100 nm, a width of 300 nm, and an angle of 85°, the following results were obtained: Figure 3 The target is a titanium dioxide grating.

[0067] Example 2

[0068] The only difference between this embodiment and Embodiment 1 is that the temperature of the electrostatic chuck is set to any other value between 80°C, 90°C, and 70°C and 90°C. All other conditions and parameters are exactly the same as in Embodiment 1.

[0069] In some embodiments, the method for fabricating a titanium dioxide grating provided in this application is performed by a semiconductor processing apparatus. Optionally, the semiconductor processing apparatus is an etching machine, such as an inductively coupled plasma (ICP) etching machine.

[0070] Comparative Example 1 The difference from Example 1 is that only one preparation process is used in the preparation process. Although it can also achieve the removal of the resist and etching of the titanium dioxide to be etched, it cannot accurately control the preparation result to be consistent with the target value.

[0071] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a titanium dioxide grating, characterized in that, The method includes the following steps: (1) Pretreatment process: pre-cleaning the chamber; (2) Initialization process: Place the titanium dioxide to be etched onto the electrostatic chuck in the processing chamber. The temperature of the electrostatic chuck is a preset value. (3) Preparation process: The target titanium dioxide grating is obtained through at least two preparation processes. The preparation parameters in the preparation process are determined according to the preparation target corresponding to the target titanium dioxide grating. The preparation target includes at least one of the target height, target width, and target angle. The preparation process includes a preliminary preparation process and a main preparation process. The preliminary preparation process is used to produce a rough titanium dioxide grating, and the main preparation process is used to produce a refined titanium dioxide grating. The initial preparation process includes a resist removal process and an etching process; wherein: The initial adhesive removal process is used to remove the base adhesive from the titanium dioxide to be etched. The initial etching process is used to etch a portion of the titanium dioxide on the titanium dioxide to be etched, thereby obtaining a rough titanium dioxide grating. The main fabrication process includes a resist removal process and an etching process; wherein: The main process for removing adhesive is used to remove the imprint adhesive on the titanium dioxide to be etched laterally, thereby controlling the step width. The etching process is used to etch a portion of the titanium dioxide on the titanium dioxide to be etched, and the step height and angle are controlled during the process.

2. The method as described in claim 1, characterized in that, The target titanium dioxide grating includes at least one step, and the fabrication target corresponds to all or part of the steps.

3. The method as described in claim 1, characterized in that, The pressure value during the preparation process is 10~60mT.

4. The method as described in claim 1, characterized in that, The radio frequency parameter value in the preparation process is 20~30W.

5. The method according to any one of claims 1 to 4, characterized in that, In step (2), the temperature of the electrostatic chuck is 70~90℃.

6. A titanium dioxide grating, characterized in that, The titanium dioxide grating is prepared by the method for preparing the titanium dioxide grating according to any one of claims 1-5.

7. A semiconductor processing apparatus, characterized in that, The semiconductor processing equipment is used to perform the method for preparing the titanium dioxide grating according to any one of claims 1-5.

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