Preparation method of micro-disk cavity and micro-disk cavity

Abstract

The invention discloses a preparation method of a micro-disk cavity and the micro-disk cavity, and the method comprises the steps: providing a silicon substrate; forming a silicon oxide layer on one side of the silicon substrate; performing chemical mechanical polishing treatment on one surface, far away from the silicon substrate, of the silicon oxide layer and the side wall of the silicon oxide layer; and etching the silicon substrate to enable the edge of the silicon oxide layer to be suspended. The technical scheme provided by the invention can be applied to the preparation of micro-disk cavities of any size, and the roughness of the side wall of the micro-disk cavity is reduced under the condition of not depending on parameter optimization in photoetching and etching processes.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a preparation method of a micro-disk cavity and the micro-disk cavity. Background Art

[0002] At present, on-chip silicon oxide optical microcavities are mainly divided into microsphere cavities, microring core cavities and microdisk cavities, among which microdisk cavities have the broadest application prospects.

[0003] The preparation process of micro-disk cavity mainly includes lithography and etching of on-chip silicon oxide layer, cleaning and etching of silicon substrate. During the preparation process of micro-disk cavity, the roughness of its side wall largely limits the quality factor of micro-disk cavity, which is crucial for the application of micro-disk cavity in low-threshold on-chip laser, optical frequency comb and micro-cavity sensor. At present, the roughness of micro-disk cavity side wall mainly depends on the parameter setting in the lithography and etching process of on-chip silicon oxide layer, such as the baking temperature and time of photoresist, the exposure amount of photolithography machine, the proportion of etching solution and etching time, etc. However, the optimization of the above process parameters requires a lot of time and money, which increases the time cost and economic cost of micro-disk cavity preparation. Summary of the invention

[0004] The invention provides a method for preparing a micro-disk cavity and the micro-disk cavity, so as to reduce the roughness of the side wall of the micro-disk cavity without relying on parameter optimization in photolithography and etching processes.

[0005] In a first aspect, the present invention provides a method for preparing a micro-disk cavity, wherein the method comprises:

[0006] Providing a silicon substrate; forming a silicon oxide layer on one side of the silicon substrate;

[0007] Performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer;

[0008] The silicon substrate is etched to leave the edge of the silicon oxide layer suspended.

[0009] Optionally, the chemical mechanical polishing is performed by a chemical mechanical polishing device, which includes: a sample table, a polishing disc and a polishing pad, the polishing pad is arranged on the polishing disc, and a polishing liquid is arranged on a side of the polishing pad away from the polishing disc; the chemical mechanical polishing treatment is performed on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer, including:

[0010] A silicon substrate provided with a silicon oxide layer is fixed on a sample stage, with a side of the silicon oxide layer away from the silicon substrate facing the polishing pad;

[0011] The side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are brought into contact with a polishing pad provided with a polishing liquid;

[0012] The sample stage and the polishing plate are driven to rotate at a first rotation speed.

[0013] Optionally, the first rotation speed ranges from 200 rpm to 400 rpm.

[0014] Optionally, the polishing liquid includes silicon oxide particles or aluminum oxide particles with a diameter ranging from 60 nm to 120 nm.

[0015] Optionally, forming a silicon oxide layer on one side of the silicon substrate includes:

[0016] forming a silicon oxide layer on one side of the silicon substrate;

[0017] forming a disk-shaped photoresist on a side of the silicon oxide layer away from the silicon substrate;

[0018] removing the silicon oxide layer outside the photoresist covered area;

[0019] Remove the photoresist.

[0020] Optional, photoresist removal, including:

[0021] The side of the silicon oxide layer away from the silicon substrate is cleaned with an acetone solution;

[0022] The side of the silicon oxide layer away from the silicon substrate is cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

[0023] Optionally, after chemical mechanical polishing is performed on a side of the silicon oxide layer away from the silicon substrate and a sidewall of the silicon oxide layer, the method further includes:

[0024] Ultrasonic cleaning is performed on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer;

[0025] The side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

[0026] Optionally, ultrasonic cleaning is performed on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer, including:

[0027] Using an acetone solution to ultrasonically clean a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer;

[0028] Using an isopropyl alcohol solution, ultrasonically clean the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer again;

[0029] Deionized water is used to ultrasonically clean the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer again.

[0030] Optionally, the silicon substrate is etched, including:

[0031] The silicon substrate is etched using xenon dioxide gas.

[0032] In a second aspect, the present invention provides a micro-disk cavity, wherein the micro-disk cavity is made by the preparation method of the micro-disk cavity provided in the first aspect.

[0033] The technical solution of the present invention adds a chemical mechanical polishing process during the preparation of the silicon oxide micro-disk cavity, and by chemical mechanical polishing the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer, the roughness of the side wall of the silicon oxide micro-disk cavity is greatly reduced, thereby improving the quality factor of the silicon oxide micro-disk cavity, and preparing the silicon oxide micro-disk cavity with the highest quality factor under the same size. The technical solution of the present invention can be applied to the preparation of micro-disk cavities of any size, and reduce the roughness of the side wall of the micro-disk cavity without relying on parameter optimization in the photolithography and etching process.

[0034] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0036] Figure 1 is a flow chart of a method for preparing a micro-disk cavity provided by an embodiment of the present invention;

[0037] Figure 2-Figure 4 It is a structural diagram corresponding to each step in a method for preparing a micro-disk cavity provided in an embodiment of the present invention;

[0038] Figure 5 is a scanning electron microscope photograph of a polished micro-disk cavity provided by an embodiment of the present invention;

[0039] Figure 6 This is an atomic force microscope measurement image before polishing provided by an embodiment of the present invention;

[0040] Figure 7 This is another atomic force microscope measurement image before polishing provided by an embodiment of the present invention;

[0041] Figure 8 This is an atomic force microscope measurement image after polishing provided by an embodiment of the present invention;

[0042] Fig. 9 This is another atomic force microscope measurement image after polishing provided by an embodiment of the present invention;

[0043] Fig.10 This is a measurement diagram of a quality factor of a micro-disk cavity characterized by a line width method before polishing provided by an embodiment of the present invention;

[0044] Fig.11 This is a measurement diagram of a quality factor of a micro-disk cavity characterized by a line width method after polishing provided by an embodiment of the present invention;

[0045] Fig.12 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention;

[0046] Fig.13 is a structural schematic diagram of a chemical mechanical polishing device provided by an embodiment of the present invention;

[0047] Fig.14 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention;

[0048] Figure 15-17 It is a structural diagram corresponding to some steps in a method for preparing a micro-disk cavity provided in an embodiment of the present invention;

[0049] Fig.18 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention;

[0050] Fig.19 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention;

[0051] Fig. 20 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention;

[0052] Fig.21 It is a flow chart of another method for preparing a micro-disk cavity provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0055] Figure 1 is a flow chart of a method for preparing a micro-disk cavity provided by an embodiment of the present invention, such as Figure 1 As shown, the method includes:

[0056] S100: providing a silicon substrate; and forming a silicon oxide layer on one side of the silicon substrate.

[0057] Specifically, Figure 2 As shown, a silicon substrate 1 is first provided, and a silicon oxide layer 2 is formed on one side of the silicon substrate 1. The silicon oxide layer 2 may be in the shape of a disk, or may be in the shape of a quadrilateral, a polygon, or a triangle, and the sidewall may have a certain inclination angle. For example, the silicon oxide layer 2 may be first grown on the entire surface of one side of the silicon substrate by a process such as thermal oxidation, and then the silicon oxide layer 2 may be formed in the shape of a disk and with a sidewall having a certain inclination angle by a process such as photolithography and etching, and the thickness of the silicon oxide layer 2 may be 8-12 um.

[0058] S110: performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0059] Specifically, Figure 3 As shown, a chemical mechanical polishing process is performed on the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2. Figure 3The polishing pad 31 and polishing particles 32 are shown as examples. A certain concentration of polishing liquid is evenly distributed on the surface of the polishing pad 31, and the polishing liquid contains polishing particles 32. When chemical mechanical polishing is performed, the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2 need to be in close contact with the polishing pad 31, and the polishing particles 32 can mechanically rub against the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2, and other chemical components of the polishing liquid can chemically react with the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2, thereby achieving the planarization of the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2, effectively reducing the roughness of the side wall of the silicon oxide 2, that is, effectively reducing the roughness of the side wall of the micro-disk cavity.

[0060] S120: Etching the silicon substrate to leave the edge of the silicon oxide layer suspended.

[0061] Specifically, Figure 4 As shown, the silicon substrate 1 is etched so that the edge of the silicon oxide layer 2 is suspended, thereby obtaining a silicon dioxide optical micro-disk cavity.

[0062] Figure 5 is a scanning electron microscope photo of a polished micro-disk cavity provided in an embodiment of the present invention, such as Figure 5 As shown, the sidewall of the micro-disk cavity has a certain curvature after polishing and is smooth and round. It can be seen that chemical mechanical polishing effectively reduces the roughness of the sidewall of the micro-disk cavity.

[0063] Figure 6 This is an atomic force microscope measurement diagram before polishing provided by an embodiment of the present invention. Figure 7 is another atomic force microscope measurement image before polishing provided by an embodiment of the present invention, Figure 8 This is an atomic force microscope measurement image after polishing provided by an embodiment of the present invention. Fig. 9 This is another atomic force microscope measurement diagram after polishing provided by an embodiment of the present invention. Root mean square roughness (RMS) can be used to characterize roughness. The larger the RMS value, the greater the roughness, that is, the rougher the surface. The smaller the RMS value, the smaller the roughness, that is, the smoother the surface. Figure 6 The AFM measurement of the sidewall of the silicon oxide layer before polishing, i.e., the sidewall of the micro-disk cavity, is shown. Figure 6 It can be seen that the RMS of the sidewall of the silicon oxide layer before polishing, that is, the sidewall of the micro-disk cavity, is 0.67 nm. Figure 8 The AFM measurement of the sidewall of the silicon oxide layer after polishing, i.e., the sidewall of the micro-disk cavity, is shown. Figure 8 It can be seen that the RMS of the sidewall of the silicon oxide layer after polishing, that is, the sidewall of the micro-disk cavity, is 0.36nm. Figure 6 and Figure 8After chemical mechanical polishing of the sidewall of the silicon oxide layer, the RMS of the sidewall of the silicon oxide layer, that is, the sidewall of the micro-disk cavity, is reduced from 0.67nm to 0.36nm, and the roughness of the sidewall of the micro-disk cavity is reduced.

[0064] Figure 7 The AFM measurement of the silicon oxide layer away from the silicon substrate before polishing is shown. Figure 7 It can be seen that the RMS of the side of the silicon oxide layer away from the silicon substrate before polishing is 0.36 nm. Fig. 9 The atomic force microscope measurement image of the polished silicon oxide layer away from the silicon substrate is shown. Fig. 9 It can be seen that the RMS of the side of the silicon oxide layer away from the silicon substrate after polishing is 0.29nm. Figure 7 and Fig. 9 After chemical mechanical polishing of the side of the silicon oxide layer away from the silicon substrate, the RMS of the side of the silicon oxide layer away from the silicon substrate is reduced from 0.36nm to 0.29nm, and the roughness of the side of the silicon oxide layer away from the silicon substrate is reduced, that is, the roughness of the upper surface of the micro-disk cavity is reduced.

[0065] Fig.10 This is a measurement diagram of a quality factor of a micro-disk cavity characterized by a line width method before polishing provided by an embodiment of the present invention. Fig.11 is a measurement diagram of a quality factor of a micro-disk cavity characterized by a line width method after polishing provided by an embodiment of the present invention, Fig.10 and Fig.11 The horizontal axis Frequency represents the frequency, and the vertical axis Transmission represents the transmittance of the laser power. The line width method uses a calibrated Mark-Zehnder interferometer to scan the mode of the microdisk cavity with a frequency-tunable pump laser to obtain a Lorentz linear transmission spectrum. Fig.10 and Fig.11 The curve corresponding to the experimental data in is the Lorentz linear transmission spectrum, and the fitting curve is obtained by fitting the Lorentz linear transmission spectrum. By fitting the Lorentz linear transmission spectrum, the line width of the corresponding mode can be obtained, and then the quality factor Q0 of the corresponding mode can be deduced.

[0066] The characterization of the quality factor Q0 requires the use of a fiber-cone coupling system. Ordinary commercial optical fibers are heated with a hydrogen flame and drawn into a cone. Laser light is introduced into the fiber cone, and the sample is moved using a translation stage so that its edge is close to the fiber cone. At this time, the laser energy in the fiber cone will enter the micro-disk cavity through evanescent field coupling. Through a photodetector and an oscilloscope, we can observe the coupling state of the fiber cone and the micro-disk cavity and obtain the corresponding Lorentz linear transmission spectrum curve. The quality factor Q0 can be obtained by fitting the Lorentz linear transmission spectrum curve.

[0067] The linewidth method is to add a low-frequency triangular wave scanning signal to the piezoelectric ceramic of the laser. The laser will output a laser with a frequency that varies within a certain range. The laser is coupled through the fiber cone, and the light with a frequency that meets the resonance conditions will enter the micro-disk cavity. The Lorentz curve is displayed on the transmission spectrum. The mode linewidth and quality factor Q0 can be obtained by fitting the curve.

[0068] The transmission spectrum of the Mach-Zehnder interferometer used to calibrate the laser scanning frequency is in the shape of a sinusoidal function, whose periodic intervals correspond to the changes in the laser frequency, and can therefore be used as a ruler to measure the line width of the sample's optical mode. Fig.10 and Fig.11 The sin function-shaped curve below can be used as a ruler to measure the line width of the sample's optical mode.

[0069] contrast Fig.10 and Fig.11 The quality factor Q0 of the micro-disk cavity before polishing is only 5.33×10 7 , and the quality factor Q0 of the microdisk cavity after polishing was increased to 6.77×10 8 , achieving an order of magnitude improvement, and this is also the silicon oxide microdisk cavity with the highest quality factor Q0 at this size.

[0070] The technical solution of the embodiment of the present invention adds a chemical mechanical polishing process during the preparation of the silicon oxide micro-disk cavity, and by chemical mechanical polishing the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer, the roughness of the side wall of the silicon oxide micro-disk cavity is greatly reduced, thereby improving the quality factor of the silicon oxide micro-disk cavity, and preparing the silicon oxide micro-disk cavity with the highest quality factor under the same size. The technical solution of the embodiment of the present invention can be applied to the preparation of micro-disk cavities of any size, and reduce the roughness of the side wall of the micro-disk cavity without relying on parameter optimization in the photolithography and etching process.

[0071] Optionally, based on the above embodiments, Fig.12 is a flow chart of another method for preparing a micro-disk cavity provided in an embodiment of the present invention, Fig.13 is a schematic diagram of the structure of a chemical mechanical polishing device provided by an embodiment of the present invention, wherein the chemical mechanical polishing is performed by the chemical mechanical polishing device, such as Fig.13 As shown, the chemical mechanical polishing device includes: a sample table 33, a polishing disc 34 and a polishing pad 31. The polishing pad 31 is arranged on the polishing disc 34, and a polishing liquid is arranged on the side of the polishing pad 31 away from the polishing disc 34. Fig.12 As shown, the method includes:

[0072] S200: providing a silicon substrate; and forming a silicon oxide layer on one side of the silicon substrate.

[0073] S210: Fixing a silicon substrate provided with a silicon oxide layer on a sample stage, with a surface of the silicon oxide layer away from the silicon substrate facing the polishing pad.

[0074] Specifically, refer to Figure 3 and Fig.13 The silicon substrate 1 provided with the oxide layer 2 is fixed on the sample stage 33, and the side of the silicon oxide layer 2 away from the silicon substrate 1 faces the polishing pad 31. A polishing liquid is provided on the side of the polishing pad 31 close to the silicon oxide layer 2, and the polishing liquid includes a polishing abrasive 32 and a chemical substance. The type and concentration of the polishing abrasive 32 and the chemical substance in the polishing liquid can be set according to actual needs.

[0075] S220: A side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer are brought into contact with a polishing pad provided with a polishing liquid.

[0076] Specifically, refer to Figure 3 and Fig.13 , control the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2 to be in close contact with the polishing pad 31, and at the same time, the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2 are also in close contact with the polishing liquid.

[0077] S230: driving the sample stage and the polishing plate to rotate at a first rotation speed.

[0078] Specifically, refer to Figure 3 and Fig.13 The chemical mechanical polishing device also includes a first motor 35 and a second motor 36. The first motor 35 drives the sample stage 33 to rotate at a first speed, and the second motor drives the polishing plate 34 to rotate at a first speed. Exemplarily, the first speed may be 300 rpm. The side of the silicon oxide layer 2 away from the silicon substrate 1 and the sidewall of the silicon oxide layer 2 generate friction with the polishing pad 31, the polishing particles 32 may mechanically rub against the side of the silicon oxide layer 2 away from the silicon substrate 1 and the sidewall of the silicon oxide layer 2, and other chemical components of the polishing liquid may chemically react with the side of the silicon oxide layer 2 away from the silicon substrate 1 and the sidewall of the silicon oxide layer 2, thereby achieving the planarization of the side of the silicon oxide layer 2 away from the silicon substrate 1 and the sidewall of the silicon oxide layer 2.

[0079] The rate of chemical mechanical polishing can be controlled by adjusting the rotation speed of the first motor 35 and the second motor 36. The polishing process will slightly reduce the thickness of the silicon oxide layer 2, and the sidewall shape of the silicon oxide layer 2 will have a certain curvature. Figure 5 As shown, the chemical mechanical polishing process can reduce the roughness of the sidewall of the silicon oxide layer 2 and improve the quality factor of the sample.

[0080] S240: Etching the silicon substrate to leave the edge of the silicon oxide layer suspended.

[0081] Optionally, based on the above embodiments, the first rotation speed ranges from 200 rpm to 400 rpm.

[0082] Specifically, refer to Figure 3 and Fig.13 In the process of chemical mechanical polishing of the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2, the rotation speed of the sample stage 33 and the polishing disk 34 can be controlled to be any rotation speed within the range of 200 rpm-400 rpm. The rotation speed of the sample stage 33 and the polishing disk 34 should not be set too large or too small. If the rotation speed of the sample stage 33 and the polishing disk 34 is set too small, the roughness of the side wall of the silicon oxide layer 2 may not meet the requirements. If the rotation speed of the sample stage 33 and the polishing disk 34 is set too large, physical damage may be caused to the micro-disk cavity sample.

[0083] Optionally, based on the above embodiments, the polishing liquid includes silicon oxide particles or aluminum oxide particles with a diameter ranging from 60 nm to 120 nm.

[0084] Specifically, refer to Figure 3 and Fig.13 The polishing liquid includes polishing particles 32, which may be silicon oxide particles or aluminum oxide particles with a diameter ranging from 60 nm to 120 nm. The diameter of the polishing particles should not be too large or too small. If the diameter of the polishing particles is too small, the roughness of the side wall of the silicon oxide layer 2 may not meet the requirements. If the diameter of the polishing particles is too large, the side of the silicon oxide layer 2 away from the silicon substrate 1 and the side wall of the silicon oxide layer 2 may be scratched.

[0085] Optionally, based on the above embodiments, Fig.14 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention, such as Fig.14 As shown, the method includes:

[0086] S300: providing a silicon substrate.

[0087] S310: forming a silicon oxide layer on one side of the silicon substrate.

[0088] Specifically, Fig.15 As shown, a silicon oxide layer 2 is formed on one side of the silicon substrate 1. In this case, the silicon oxide layer 2 is formed on the entire surface of one side of the silicon substrate 1. Exemplarily, a silicon oxide layer 2 with a thickness of 8-12 um is grown on one side of the silicon substrate 1 by a thermal oxidation process, and then the sample is cleaned to remove impurities and residues.

[0089] S320: forming a disk-shaped photoresist on a side of the silicon oxide layer away from the silicon substrate.

[0090] Specifically, Fig.16As shown, a disc-shaped photoresist 4 is formed on the side of the silicon oxide layer 2 away from the silicon substrate 1. For example, a layer of photoresist 4 can be firstly spin-coated on the entire surface of the side of the silicon oxide layer 2 away from the silicon substrate 1, and then a mask with a circular pattern of a certain diameter is used as a mask, and the photoresist 4 is exposed using a photolithography machine. After exposure, the sample is immersed in a developer and developed for a period of time to obtain a layer of disc-shaped photoresist 4. The photoresist 4 can be in the shape of a disc or any other shape, for example, it can be a quadrilateral, a polygon or a triangle. The shape of the photoresist 4 determines the final shape of the silicon oxide layer 2.

[0091] S330: removing the silicon oxide layer outside the photoresist covered area.

[0092] Specifically, Fig.17 As shown, the silicon oxide layer 2 outside the area covered by the photoresist 4 is removed. Exemplarily, the silicon oxide layer 2 is wet-etched using the photoresist 4 as a mask, and the solution used for etching can be a buffered hydrofluoric acid solution. After the silicon oxide layer 2 outside the area covered by the photoresist 4 is etched, it is necessary to continue etching for a period of time to ensure that the microcavity forms a continuous and smooth sidewall. After the etching is completed, the silicon oxide layer 2 is etched into a disk shape with a certain inclination angle.

[0093] S340: removing the photoresist.

[0094] Specifically, Figure 2 As shown, the photoresist 4 is removed, and wet stripping and dry stripping can be used to remove the photoresist 4. For example, a mixed solution of potassium hydroxide and sodium hydroxide can be used to remove the photoresist 4, or the photoresist 4 can be oxidized into gas using oxygen plasma and then pumped away by a vacuum pump.

[0095] S350: performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0096] Specifically, chemical mechanical polishing can also remove the photoresist 4 that cannot be completely removed by some chemical cleaning methods, and can also improve the quality factor of the micro-disk cavity.

[0097] S360: Etching the silicon substrate to leave the edge of the silicon oxide layer suspended.

[0098] Optionally, based on the above embodiments, Fig.18 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention, such as Fig.18 As shown, the method includes:

[0099] S400: providing a silicon substrate.

[0100] S410: forming a silicon oxide layer on one side of the silicon substrate.

[0101] S420: forming a disk-shaped photoresist on a side of the silicon oxide layer away from the silicon substrate.

[0102] S430: removing the silicon oxide layer outside the photoresist covered area.

[0103] S440: Cleaning the side of the silicon oxide layer away from the silicon substrate with an acetone solution.

[0104] Specifically, Fig.17 As shown, firstly, the side of the silicon oxide layer 2 away from the silicon substrate 1 is cleaned with an acetone solution to remove the photoresist 4 on the side of the silicon oxide layer 2 away from the silicon substrate 1. Acetone is a polar solvent, and the oxygen atoms in its molecules can form hydrogen bonds with the polar groups in the photoresist 4, so that the photoresist 4 can be dissolved in the acetone, thereby achieving the removal of the photoresist 4.

[0105] S450: The side of the silicon oxide layer away from the silicon substrate is cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

[0106] Specifically, Fig.17 As shown, acetone can be used to remove most of the photoresist 4, and the remaining small part of the photoresist 4 needs to be further cleaned using a mixed solution of concentrated sulfuric acid and hydrogen peroxide. The mixed solution of concentrated sulfuric acid and hydrogen peroxide mainly removes the photoresist 4 through oxidation, and finally achieves complete removal of the photoresist 4.

[0107] S460: performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0108] Specifically, chemical mechanical polishing can also remove photoresist impurities that cannot be completely removed by some chemical cleaning methods, and can also improve the quality factor of the micro-disk cavity.

[0109] S470: Etching the silicon substrate to leave the edge of the silicon oxide layer suspended.

[0110] Optionally, based on the above embodiments, Fig.19 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention, such as Fig.19 As shown, the method includes:

[0111] S500: providing a silicon substrate; and forming a silicon oxide layer on one side of the silicon substrate.

[0112] S510: performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0113] S520: ultrasonically cleaning a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0114] Specifically, after chemical mechanical polishing of the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer, the polished sample needs to be ultrasonically cleaned to remove the polishing particles, dirt and residues remaining in the sample. The polishing particles, dirt and residues remaining in the sample are removed by ultrasonic vibration.

[0115] S530: The side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

[0116] Specifically, after ultrasonic cleaning, the polished sample is cleaned again with a mixed solution of concentrated sulfuric acid and hydrogen peroxide. The mixed solution of concentrated sulfuric acid and hydrogen peroxide mainly removes organic pollutants remaining in the sample after polishing. The quality and yield of the micro-disk cavity can be further improved and the defects of the micro-disk cavity can be reduced by two cleanings after polishing.

[0117] S540: Etching the silicon substrate to leave the edge of the silicon oxide layer suspended.

[0118] Optionally, based on the above embodiments, Fig. 20 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention, such as Fig. 20 As shown, the method includes:

[0119] S600: providing a silicon substrate; and forming a silicon oxide layer on one side of the silicon substrate.

[0120] S610: performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0121] S620: using an acetone solution to ultrasonically clean a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0122] Specifically, after polishing, the side of the silicon oxide layer away from the silicon substrate and the sidewalls of the silicon oxide layer are first ultrasonically cleaned using an acetone solution. Acetone is an effective organic solvent that can dissolve many organic substances, including oil and grease. Through ultrasonic cleaning, acetone can penetrate into the tiny gaps on the sample surface and effectively remove these organic residues.

[0123] S630: Using an isopropyl alcohol solution, ultrasonically clean the side of the silicon oxide layer away from the silicon substrate and the sidewall of the silicon oxide layer again.

[0124] Specifically, the side of the silicon oxide layer away from the silicon substrate and the sidewalls of the silicon oxide layer are then ultrasonically cleaned again using an isopropyl alcohol solution, which is also an effective solvent for further removing residues that were not completely removed by acetone. The isopropyl alcohol cleaning step helps ensure the purity of the sample and is ready for subsequent processing or analysis.

[0125] S640: Use deionized water to ultrasonically clean the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer again.

[0126] Specifically, the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are ultrasonically cleaned again with deionized water. The purpose of this step is to remove the residual isopropanol on the sample and ensure the cleanliness of the sample surface, providing a clean foundation for the next experiment or application. Deionized water can effectively rinse away any residues left in the previous cleaning process to avoid contamination of the sample.

[0127] S650: The side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

[0128] S660: Etching the silicon substrate to leave the edge of the silicon oxide layer suspended.

[0129] Optionally, based on the above embodiments, Fig.21 is a flow chart of another method for preparing a micro-disk cavity provided by an embodiment of the present invention, such as Fig.21 As shown, the method includes:

[0130] S700: providing a silicon substrate; and forming a silicon oxide layer on one side of the silicon substrate.

[0131] S710: performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer.

[0132] S720: etching the silicon substrate using xenon dioxide gas.

[0133] Specifically, Figure 4 As shown, the silicon substrate is etched using xenon dioxide gas. The xenon dioxide gas can react with the silicon substrate 1 at room temperature to perform dry etching on the silicon substrate 1. Its etching characteristics are isotropic, which means that it can remove materials evenly in all directions of the silicon substrate 1, thereby ensuring the uniformity and consistency of the etching.

[0134] An embodiment of the present invention provides a micro-disk cavity, wherein the micro-disk cavity is manufactured by the method for preparing a micro-disk cavity provided by any of the above embodiments, and has the beneficial effects of the method for preparing a micro-disk cavity provided by any of the above embodiments of the present invention.

[0135] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0136] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a micro-disk cavity, characterized in that: include: providing a silicon substrate; forming a silicon oxide layer on one side of the silicon substrate; Performing chemical mechanical polishing on a side of the silicon oxide layer away from the silicon substrate and a sidewall of the silicon oxide layer; The silicon substrate is etched to leave the edge of the silicon oxide layer suspended.

2. The method for preparing a micro-disk cavity according to claim 1, characterized in that: The chemical mechanical polishing is performed by a chemical mechanical polishing device, which includes: a sample stage, a polishing disc and a polishing pad, wherein the polishing pad is arranged on the polishing disc, and a polishing liquid is arranged on a side of the polishing pad away from the polishing disc; the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are subjected to chemical mechanical polishing, including: Fixing the silicon substrate provided with the silicon oxide layer on the sample stage, with a side of the silicon oxide layer away from the silicon substrate facing the polishing pad; Making a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer contact with a polishing pad provided with the polishing liquid; The sample stage and the polishing plate are driven to rotate at a first rotation speed.

3. The method for preparing a micro-disk cavity according to claim 2, characterized in that: The first rotation speed ranges from 200 rpm to 400 rpm.

4. The method for preparing a micro-disk cavity according to claim 2, characterized in that: The polishing liquid includes silicon oxide particles or aluminum oxide particles with a diameter ranging from 60nm to 120nm.

5. The method for preparing a micro-disk cavity according to claim 1, characterized in that: Forming a silicon oxide layer on one side of the silicon substrate, comprising: forming the silicon oxide layer on one side of the silicon substrate; forming a disk-shaped photoresist on a side of the silicon oxide layer away from the silicon substrate; removing the silicon oxide layer outside the photoresist covered area; The photoresist is removed.

6. The method for preparing a micro-disk cavity according to claim 5, characterized in that: Removing the photoresist, comprising: Using an acetone solution to clean the side of the silicon oxide layer away from the silicon substrate; The side of the silicon oxide layer away from the silicon substrate is cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

7. The method for preparing a micro-disk cavity according to claim 1, characterized in that: After chemical mechanical polishing is performed on a side of the silicon oxide layer away from the silicon substrate and a sidewall of the silicon oxide layer, the method further comprises: Ultrasonic cleaning is performed on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer; The side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer are cleaned again using a mixed solution of concentrated sulfuric acid and hydrogen peroxide.

8. The method for preparing a micro-disk cavity according to claim 7, characterized in that: Ultrasonic cleaning is performed on a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer, comprising: Using an acetone solution to ultrasonically clean a side of the silicon oxide layer away from the silicon substrate and a side wall of the silicon oxide layer; Using an isopropanol solution, ultrasonically clean the side of the silicon oxide layer away from the silicon substrate and the sidewall of the silicon oxide layer again; Deionized water is used to ultrasonically clean the side of the silicon oxide layer away from the silicon substrate and the side wall of the silicon oxide layer again.

9. The method for preparing a micro-disk cavity according to claim 1, characterized in that: The silicon substrate is subjected to an etching process, comprising: The silicon substrate is etched using xenon dioxide gas.

10. A microdisk chamber, characterized in that: The micro-disk cavity is made by the micro-disk cavity preparation method according to any one of claims 1 to 9.

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