Wet etching device and nanostructure array etching processing method

Abstract

The invention discloses a wet etching device and a nanostructure array etching processing method, and relates to the technical field of semiconductor processing. The processing module of the wet etching device comprises a shell, an etching container, a movable loader, a direct-acting unit and a transverse-acting unit, the shell is provided with a direct-acting groove and a transverse-acting channel, the etching container is used for accommodating an etching solution, the movable loader is used for loading a device to be processed, and the transverse-acting unit is used for loading the device to be processed. The direct-acting unit is used for controlling the movable loader to ascend and descend along the direct-acting groove so that the to-be-processed device can be immersed in or leave the etching solution, and the transverse-acting unit is used for controlling the movable loader to transversely move along the transverse-acting channel; based on the wet etching device, the invention further provides a nanostructure array etching processing method which can be used for preparing a stepped silicon nanopore structure array. The wet etching device provided by the invention has relatively high etching precision, processing efficiency and automation degree, and reduces uncertainty and potential safety hazards caused by frequent manual operation.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor processing technology, and in particular to a wet etching device and a nanostructure array etching processing method. Background Art

[0002] Silicon nanostructures such as silicon nanopores, as a microscopic structure on the silicon surface, have extremely significant light capture capabilities. The stepped silicon nanostructure array can artificially control the structural parameters of each segment to achieve absorption and scattering of light of specific wavelengths. Therefore, it has great application prospects in microelectronic devices, optoelectronic devices, microfluidic devices, sensors, etc.

[0003] Stepped silicon nanostructure arrays can be prepared by metal-assisted chemical etching methods, which mainly involve preparing a precious metal mask through colloidal lithography, and then performing multiple etchings by manually processing samples, cleaning, replacing etching solutions, or controlling component concentrations. This method requires manual timing by experimenters and manual replacement of chemical reagents, which has low time accuracy and high safety risks, and is very likely to result in operational errors, which may harm experimenters. Moreover, the main parameters considered in the preparation of stepped silicon nanostructure arrays, such as the hole spacing and depth of each section of the stepped holes, all have extremely precise requirements for etching time. Any slight deviation will have a greater impact on the microscopic scale, making it impossible to accurately obtain the required etching structure parameters. Summary of the invention

[0004] The present invention provides a wet etching device and a nanostructure array etching processing method, aiming to improve the precision, efficiency and safety of step-type silicon nanostructure array etching processing.

[0005] The wet etching device provided by the present invention includes a processing module, and the processing module includes:

[0006] A housing is formed with a receiving cavity; a surface of the housing is provided with a direct-acting groove in a vertical direction; a through gap is left between the top of the direct-acting groove and the top of the housing, and the gap forms a transverse motion channel;

[0007] An etching container is provided on the same surface of the housing as the direct-acting groove and is located below the direct-acting groove; the etching container is used to contain an etching solution;

[0008] A movable loader for loading the device to be processed;

[0009] A direct-acting unit is disposed in the accommodating chamber; the direct-acting unit is connected to the movable loader and is used to control the lifting and lowering of the movable loader so that the device to be processed is immersed in or leaves the etching solution;

[0010] A traverse unit is arranged in the accommodating cavity; the traverse unit is connected to the movable loader and is used to control the movable loader to move laterally along the traverse channel.

[0011] Optionally, the direct-acting unit includes a direct-acting motor, a direct-acting gear and a direct-acting rack;

[0012] The direct-acting rack is arranged in a vertical direction and meshes with the direct-acting gear;

[0013] The direct-acting motor is used to drive the direct-acting gear to rotate so that the direct-acting rack moves in a vertical direction, and the direct-acting rack drives the movable loader to move up and down.

[0014] Optionally, the traverse unit comprises a traverse motor, a traverse gear, a traverse gear shaft and a traverse rack;

[0015] The traverse rack is arranged in the horizontal direction; the traverse rack is fixedly connected to the movable loader and can be meshed with the traverse gear;

[0016] The traverse motor drives the traverse gear to rotate via the traverse gear shaft, so that the traverse rack meshing with the traverse gear moves laterally, thereby driving the movable loader to move laterally.

[0017] Optionally, the processing module is further provided with a connecting groove;

[0018] Any one of the plurality of processing modules is detachably connected to another one at the connection groove via a fastener;

[0019] The traverse unit controls the lateral movement of the movable loader so that the movable loader is transferred from one processing module to another processing module.

[0020] Optionally, a control module is also included;

[0021] The control module includes a memory and a processor;

[0022] The memory is used to store a computer program; the processor executes the computer program to control the operation of the linear motor and the traverse motor.

[0023] The nanostructure array etching processing method provided by the present invention adopts the wet etching device described above, and the method comprises the following steps:

[0024] S1, preparing a photoresist nanopore mask and a noble metal layer on the surface of the device to be processed;

[0025] S2, adding an etching solution into an etching container of the wet etching device, and loading a device to be processed onto a movable loader of the wet etching device;

[0026] S3, immersing the movable loader into the etching solution and setting the etching time;

[0027] S4, etching is completed, and the movable loader is raised until the device to be processed is completely out of the etching solution.

[0028] Optionally, the wet etching device includes a first processing module, a second processing module and a third processing module, and step S2 of the method specifically includes:

[0029] Adding a first etching solution, a second etching solution, and a third etching solution into etching containers of the first processing module, the second processing module, and the third processing module, respectively;

[0030] The first etching solution is used to axially etch the device to be processed under the catalysis of the precious metal layer to obtain a first step hole segment; the second etching solution is used to radially etch the first step hole segment to expand the diameter of the first step hole segment; the third etching solution is used to axially etch the device to be processed from the bottom of the first step hole segment under the catalysis of the precious metal layer to obtain a second step hole segment.

[0031] Optionally, the method sequentially uses the first processing module, the second processing module and the third processing module to etch the device to be processed, and performs step S3 and step S4 when using any one of the first processing module, the second processing module and the third processing module.

[0032] Optionally, the material of the device to be processed is at least one of silicon, gallium arsenide, and silicon carbide.

[0033] The present invention further provides a semiconductor device having a stepped nanostructure array, wherein the stepped nanostructure array is prepared by the wet etching device described above, or by the nanostructure array etching method described above.

[0034] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0035] The wet etching device provided by the present invention loads the device to be processed on a movable loader, and the operator can control the lifting and lowering of the movable loader through a linear motion unit to immerse the device to be processed in or out of the etching solution, and after the movable loader rises to the top of the linear motion groove, the movable loader can be controlled to move horizontally through a transverse motion unit to make the device to be processed leave the processing module where it is located or enter a new processing module for the next step of operation; using the wet etching device, it is only necessary to configure different etching solutions and prepare masked devices to be processed in advance, and the entire etching process avoids close manual contact with the etching solution, reducing the safety hazards caused by frequent manual operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 paying creative labor.

[0037] Figure 1 It is a front structural schematic diagram of an embodiment of a processing module of a wet etching device of the present invention;

[0038] Figure 2 for Figure 1 A schematic diagram of the cross-sectional side view of the processing module shown;

[0039] Figure 3 A schematic diagram of the assembly structure and movement process of an embodiment of a wet etching device of the present invention;

[0040] Figure 4 It is a flowchart of an embodiment of a method for etching a nanostructure array according to the present invention;

[0041] Figure 5 Schematic diagram of the structure of the stepped silicon nanostructure array of the present invention.

[0042] Description of Figure Numbers:

[0043] 1. Shell; 2. Etching container; 3. Removable loader; 6. Fastener; 11. Direct-acting groove; 12. Connecting groove; 41. Direct-acting motor; 42. Direct-acting gear; 43. Direct-acting rack; 51. Transverse-acting motor; 52. Transverse-acting gear; 53. Transverse-acting gear shaft; 54. Transverse-acting rack; 100. First processing module; 200. Second processing module; 300. Third processing module; A1. First etching container; A2. Second etching container; A3. Third etching container; 1001. Silicon substrate; 1002. Nanochannel; 1002-1. First stepped hole segment; 1002-2. Second stepped hole segment; 1003. Photoresist mask; 1004. Gold nanoparticles. DETAILED DESCRIPTION

[0044] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions 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 embodiments described below 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 are within the scope of protection of the present invention.

[0045] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and drawings of the present application 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 application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations 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.

[0046] In current research, stepped silicon nanostructure arrays can be prepared by dry etching, but dry etching faces the challenge of difficult control of directional motion of etching gas, making it difficult to generate complex structures; in addition, the sidewalls of dry-etched through-holes often present a scallop shape, and the process chain is long, which not only has high equipment costs but also low efficiency. Stepped silicon nanostructure arrays can also be prepared by traditional wet etching, but traditional wet etching can usually only prepare micro-nanostructures with simple shapes and small aspect ratios due to its isotropic characteristics.

[0047] In contrast, the metal-assisted chemical etching method is a cost-effective, simple, large-scale wet etching method that does not require entry into a clean room. In the metal-assisted chemical etching method, the oxidant (usually hydrogen peroxide) is reduced under the catalysis of the deposited noble metal, and at the same time, holes are generated in the noble metal and injected into the silicon. Under the action of hydrofluoric acid, the silicon is oxidized into a soluble product, silicon hexafluoride, and hydrogen is generated as a by-product; the reaction rate of the surface of the silicon wafer covered by the noble metal is much greater than that of the uncovered surface, so the noble metal sinks into the silicon substrate, thereby forming a silicon nanostructure on the substrate, such as the noble metal mesh can etch out silicon nanowires, and the noble metal particles can etch out silicon nanopore structures. By controlling the initial morphology of the noble metal mask deposition, the substrate is removed in a directional manner under its catalytic action, so that a large-area, stepped silicon nanostructure array can be prepared. Therefore, the metal-assisted chemical etching processing technology has become the main method for preparing stepped silicon nanostructure arrays.

[0048] However, after extensive investigation and research, the applicant found that the current metal-assisted chemical etching method for preparing stepped silicon nanostructure arrays still remains at the stage of manually processing samples, cleaning, replacing etching solutions or controlling component concentrations for multiple etchings. Manual operation of chemical reagent replacement has low time accuracy, high safety risks, and is very likely to cause operational errors, which will harm the experimenters. In addition, the main parameters considered in the preparation of stepped silicon nanostructure arrays, such as the hole spacing and depth of each section of the stepped holes, have extremely precise requirements for etching time. Any slight deviation will have a greater impact on the microscopic scale, so that the required etching structure parameters cannot be accurately obtained. Therefore, there is an urgent need for a wet etching device with high automation, good safety performance, good controllability and high control accuracy to improve the production and research status of stepped silicon nanostructure arrays.

[0049] The present invention provides a wet etching device, aiming to solve the above problems.

[0050] See also Figure 1 and Figure 2 In one embodiment, the wet etching device provided by the present invention includes a processing module, and the processing module includes:

[0051] The housing 1 is formed with a receiving cavity; a linear motion groove 11 is formed on one surface of the housing 1 in a vertical direction; a through gap is left between the top of the linear motion groove 11 and the top of the housing 1, and the gap forms a traverse channel;

[0052] The etching container 2 is provided on the same surface of the housing 1 as the direct-acting groove 11 and is located below the direct-acting groove 11; the etching container 2 is used to contain the etching solution;

[0053] A movable loader 3, used for loading the device to be processed;

[0054] The direct-acting unit is arranged in the accommodating cavity of the housing; the direct-acting unit is connected to the movable loader 3 and is used to control the movable loader 3 to rise and fall along the direct-acting groove 11 so that the device to be processed is immersed in or leaves the etching solution;

[0055] The traverse unit is arranged in the accommodating cavity of the shell; the traverse unit is connected to the movable loader 3 and is used to control the movable loader 3 to move horizontally along the traverse channel.

[0056] In this embodiment, the device to be processed can be a semiconductor material device such as silicon, gallium arsenide, silicon carbide, etc.

[0057] In this embodiment, a photoresist mask or a noble metal layer is prepared on the surface of the device to be processed before etching, so as to form a desired structure or pattern after wet etching.

[0058] In this embodiment, the shell 1 of the processing module is provided with a linear motion groove 11, and the linear motion unit drives the movable loader 3 to rise and fall along the linear motion groove 11; when the movable loader 3 rises to the transverse motion channel located above the linear motion groove 11, the movable loader 3 can be driven by the transverse motion unit to move laterally along the transverse motion channel.

[0059] In this embodiment, the direct-motion unit is used to control the lifting and lowering of the device to be processed so as to enter or leave the etching solution. After the movable loader rises to the top of the direct-motion groove, the lateral movement unit can be used to control the movable loader to move laterally so that the device to be processed leaves the processing module in which it is located or enters a new processing module for the next step of operation. By using this wet etching device, it is only necessary to configure different etching solutions and prepare masked devices to be processed in advance. The entire etching process avoids close manual contact with the etching solution, thereby reducing the safety hazards caused by frequent manual operations.

[0060] Further, see Figure 2 In a specific embodiment, the direct-acting unit includes a direct-acting motor 41, a direct-acting gear 42 and a direct-acting rack 43;

[0061] The direct-acting rack 43 is arranged in the vertical direction and meshes with the direct-acting gear 42;

[0062] The direct-acting motor 41 is used to drive the direct-acting gear 42 to rotate, so that the direct-acting rack 43 moves in the vertical direction, and the direct-acting rack 43 drives the movable loader 3 to rise and fall; the direct-acting motor 41 can be a DC motor, an AC asynchronous motor, a stepping motor, a servo motor, etc.

[0063] In this embodiment, the direct-acting rack 43 can be fixedly connected to the movable loader 3, and the direct-acting rack 43 moves in the vertical direction to directly drive the movable loader 3 to rise and fall; the direct-acting rack 43 can also abut against the movable loader 3, and when the direct-acting rack 43 moves in the vertical direction, it pushes the movable loader 3 to rise and fall.

[0064] Further, see Figure 2 In a specific embodiment, the traverse unit includes a traverse motor 51, a traverse gear 52, a traverse gear shaft 53 and a traverse rack 54;

[0065] The traverse rack 54 is arranged in the horizontal direction; the traverse rack 54 is fixedly connected to the movable loader 3 and can be meshed with the traverse gear 52;

[0066] The traverse motor 51 drives the traverse gear 52 to rotate through the traverse gear shaft 53, so that the traverse rack 54 meshing with the traverse gear 52 moves laterally, thereby driving the movable loader 3 to move laterally; the traverse motor 51 can be a DC motor, an AC asynchronous motor, a stepping motor, a servo motor, etc.

[0067] In a specific embodiment, the traverse gear 52 is arranged at the top of the accommodating cavity of the shell 1. First, the movable loader 3 is lifted by the direct-acting unit until the traverse rack 54 is just engaged with the traverse gear 52, and then the traverse motor 51 drives the traverse gear 52 to rotate, and then the movable loader 3 is moved laterally along the traverse channel through the movement of the traverse rack 54.

[0068] Further, see Figure 1 and Figure 3 In one embodiment, the wet etching device includes a plurality of processing modules, each processing module is further provided with a connecting groove 12;

[0069] Any one of the plurality of processing modules is detachably connected to another at the connection groove 12 via a fastener 6;

[0070] The traverse unit controls the lateral movement of the movable loader 3 so that the movable loader 3 is transferred from one processing module to another processing module.

[0071] In this embodiment, the connection groove 12 is used for detachable connection between processing modules, and the fastener 6 includes one or more of a bolt, a nut, a screw, a stud, and a washer.

[0072] In this embodiment, by setting up multiple detachably connected processing modules, the required number of processing modules can be selected according to actual etching requirements and the processing modules can be arranged and combined, and the corresponding etching solution can be added to the etching container of each processing module. The lateral motion unit and the linear motion unit can be used to control the device to be processed to enter different processing modules in turn to complete the corresponding etching steps. This is suitable for a wet etching process including multiple etching steps.

[0073] Further, based on the above embodiments, in one embodiment, the wet etching device further includes a control module;

[0074] The control module includes a memory and a processor;

[0075] The memory is used to store a computer program; the processor executes the computer program to control the linear motor and the traverse motor to work.

[0076] In this embodiment, the computer program includes a timing module to set the etching time, thereby starting and stopping the motor, that is, the timing module controls the start of the direct-acting motor of the corresponding processing module, thereby causing the movable loader to descend or rise, and starting or ending the etching process in the processing module.

[0077] This embodiment can use a computer program to enable the wet etching device to automatically etch the device to be processed according to specified steps and specified time, reducing the uncertainty caused by frequent manual operations and improving the etching accuracy, processing efficiency and automation level of the wet etching process.

[0078] In an optional implementation, the control module is a single chip microcomputer.

[0079] Furthermore, in one embodiment, each processing module of the wet etching device is also provided with an ultrasonic vibration device; when the device to be processed is etched in the etching solution, the ultrasonic vibration device is started to ultrasonically perform ultrasound on the device to be processed to remove bubbles and holes generated by etching, so as to make the etching more complete.

[0080] From the above, it can be seen that the wet etching device proposed in the embodiment of the present invention can select the number of processing modules and the type of etching solution according to the etching requirements of the specific device to be processed, and etch the device to be processed in specified steps and time. It only needs to configure different etching solutions and prepare masked devices to be processed in advance to automatically complete the etching process. Compared with manual operation, the wet etching process of the device to be processed using the wet etching device provided in the embodiment of the present invention has higher etching accuracy, processing efficiency and degree of automation, and reduces the uncertainty and safety hazards caused by frequent manual operation.

[0081] Based on the above-mentioned embodiment of the wet etching device, the present invention provides a nanostructure array etching processing method.

[0082] In one embodiment, the nanostructure array etching process comprises the following steps:

[0083] S1, preparing a photoresist nanopore mask and a noble metal layer on the surface of the device to be processed;

[0084] S2, adding an etching solution into an etching container of the wet etching device, and loading a device to be processed onto a movable loader of the wet etching device;

[0085] S3, immersing the movable loader into the etching solution and setting the etching time;

[0086] S4, etching is completed, and the movable loader is raised until the device to be processed is completely out of the etching solution.

[0087] In this embodiment, the nanostructure refers to a nanoscale structure formed in the device to be processed by etching, such as a nanowire, a nanogroove, a nanohole, etc.

[0088] In this embodiment, the material of the device to be processed is at least one of silicon, gallium arsenide, and silicon carbide.

[0089] The present method embodiment prepares the nanostructure array through the wet etching device provided by the aforementioned embodiment. Therefore, the beneficial effects possessed by the aforementioned wet etching device embodiment can also be achieved by the present method embodiment and will not be elaborated herein.

[0090] See also Figure 4 In order to explain in detail the wet etching device and the nanostructure array etching processing method proposed in this application, this application also proposes a specific embodiment for etching to prepare a stepped silicon nanopore structure array.

[0091] In this embodiment, the wet etching device includes a first processing module 100, a second processing module 200 and a third processing module 300. The first processing module 100, the second processing module 200 and the third processing module 300 respectively include etching containers A1, A2 and A3. Figure 3 .

[0092] In this embodiment, the stepped silicon nanopore structure array at least includes a silicon substrate 1001 and a nanopore 1002 disposed in the silicon substrate 1001. The nanopore 1002 includes a first stepped pore section 1002-1 with a larger diameter and a second stepped pore section 1002-2 with a smaller diameter. Figure 5 .

[0093] The steps of preparing the stepped silicon nanopore structure array in this embodiment are specifically as follows:

[0094] Silicon wafer preparation: including cleaning dust and impurities, preparing a noble metal mask and placing it in the etching device. Specifically, select an N-type undoped silicon wafer, use step-by-step photolithography, develop and prepare a photoresist nanopore mask, cut the silicon wafer, and rinse and dry it with deionized water.

[0095] Preparation of etching solution: according to the etching steps, prepare MACE etching solution and KOH of various components and add them into the etching container; specifically, add the first etching solution, the second etching solution and the third etching solution into etching containers A1, A2 and A3 respectively.

[0096] Etching the first step hole segment: input the etching time through the control module, click the start button of the wet etching device, the movable loader sinks to immerse the silicon wafer into the etching container A1, and the etching begins; at the same time, the external ultrasonic vibration is turned on to remove the bubbles and holes generated by the etching, so that the etching is more complete; when the etching time is reached, the external ultrasonic vibration stops, the chip of the control module receives the instruction, the direct-acting motor is turned on, and the movable loader is driven to rise, and the etching stops, that is, the etching of the first step hole segment 1002-1 is completed.

[0097] Etching to expand the radius of the first step hole segment: according to the etching method, install the movable loader of the etching device into the etching container A2; input the etching time, click the start button of the wet etching device, the movable loader sinks, and the etching starts; at the same time, the external ultrasonic vibration is turned on to remove the bubbles and holes generated by the etching, so that the etching is more complete; when the etching time is reached, the external ultrasonic vibration stops, the chip of the control module receives the instruction, the direct-acting motor is turned on, and the movable loader is driven to rise, and the etching stops, that is, the etching is completed to expand the radius of the first step hole segment 1002-1.

[0098] Etching the second step hole segment: according to the etching method, install the movable loader of the etching device into the etching container A3; input the etching time, click the start button of the wet etching device, the movable loader sinks, and the etching starts; at the same time, the external ultrasonic vibration is turned on to remove the bubbles and holes generated by the etching, so that the etching is more complete; when the etching time is reached, the external ultrasonic vibration stops, the chip of the control module receives the instruction, the direct-acting motor is turned on, and the movable loader is driven to rise, and the etching stops, and the etching of the second step hole segment 1002-2 is completed.

[0099] Repeat similar steps to complete the step etching.

[0100] The etching is completed.

[0101] In this embodiment, the first etching solution is used to axially etch the silicon wafer under the catalysis of gold nanoparticles to obtain the first step hole segment 1002-1; the second etching solution is used to radially etch the first step hole segment 1002-1 to expand the diameter of the first step hole segment 1002-1; the third etching solution is used to axially etch the device to be processed from the bottom of the first step hole segment 1002-1 under the catalysis of gold nanoparticles to obtain the second step hole segment 1002-2.

[0102] Specifically, an etching solution is prepared according to the etching requirements of the required stepped silicon nanopore structure array, wherein the first etching solution is a MACE etching solution (metal chemical etching solution), and the second etching solution is a KOH etching solution, and the second etching solution is a MACE etching solution with different component concentrations; the MACE etching solution includes an oxidant and hydrofluoric acid, the oxidant (usually hydrogen peroxide) is reduced under the catalysis of the deposited gold nanoparticles, and at the same time, holes are generated in the gold nanoparticles and injected into the silicon, and under the action of hydrofluoric acid, the silicon is oxidized into a soluble product silicon hexafluoride, and hydrogen is generated as a by-product; KOH can react with silicon to corrode silicon, and on the basis of the metal-assisted chemical etching method, the sample that has been initially etched is cleaned by soaking in hydrofluoric acid to remove the silicon dioxide on the inner wall of the silicon nanopore structure, exposing the silicon substrate, and then reacting with the KOH etching solution to corrode the inner wall of the etched pore structure, thereby expanding the pore size.

[0103] After the etching solution is injected into the corresponding etching container, the first processing module 100, the second processing module 200 and the third processing module 300 are used in sequence to etch the silicon wafer. When executing the etching processing step corresponding to any processing module, the movable loader is immersed in the etching solution through the direct-motion unit, and the etching time is set. After completing the corresponding etching step, the direct-motion unit lifts the movable loader until the silicon wafer completely leaves the etching solution, and drives the movable loader to transfer to the next processing module through the transverse-motion unit for the next processing step.

[0104] In this embodiment, the depths of the first step hole segment 1002 - 1 and the second step hole segment 1002 - 2 , as well as the diameter of the first step hole segment 1002 - 1 , can be controlled by adjusting the etching time.

[0105] In this embodiment, by repeating the above-mentioned etching steps of the stepped silicon nanopore structure array, the preparation of more stepped pore segments can be achieved, that is, after etching the second stepped pore segment 1002-2, the pore size of the second stepped pore segment 1002-2 can be enlarged by using a KOH etching solution, and the third stepped pore segment can be further etched by using a MACE etching solution. By repeating these steps, more stepped pore segments can be prepared.

[0106] In this embodiment, the material of the etching container can be polytetrafluoroethylene to prevent hydrofluoric acid from corroding the etching container and ensure reliability in long-term use.

[0107] This embodiment adopts the wet etching device provided by the previous embodiment to automatically complete the etching requirements of the silicon nanopore array according to the specified steps and the specified time, and the starting speed can be changed by simply changing the motor duty cycle. It has high control accuracy, control efficiency, stability and degree of automation, and reduces the uncertainty and safety hazards caused by frequent manual operations. In addition, the wet etching device can arrange and combine multiple processing modules according to actual needs to realize the etching of multiple stepped hole segments.

[0108] It should be noted that the nanostructure array etching processing method provided in the embodiment of the present invention can not only prepare a stepped silicon nanopore structure array, but also prepare other silicon nanostructure arrays, such as silicon nanogroove arrays, stepped silicon nanogroove arrays, silicon nanowires, stepped silicon nanowires and other structures; in addition, other semiconductor materials such as gallium arsenide and silicon carbide can also be used to prepare gallium arsenide nanopores, nanogrooves, nanowires, or silicon carbide nanopores, nanogrooves, nanowires. When preparing the nanostructures of these materials, the same wet etching device is used, and only the appropriate etching solution needs to be replaced and a new computer timing program needs to be input. For example, when performing metal-assisted chemical etching on gallium arsenide, the etching solution can be replaced with a KMnO4 / H2SO4 etching solution.

[0109] The present invention also proposes a semiconductor device having a stepped nanostructure array. The stepped nanostructure array (such as a stepped nanohole array, a nanogroove array, a nanowire array) is prepared by the wet etching device provided in the aforementioned embodiment, or by the nanostructure array etching processing method provided in the aforementioned embodiment.

[0110] In a specific embodiment, the semiconductor device is a solar cell, and the stepped silicon nanostructure can be used as a light absorption layer to effectively improve the solar cell's ability to absorb light of different wavelengths, thereby improving the cell's photoelectric conversion efficiency.

[0111] In another specific embodiment, the semiconductor device is an integrated circuit element, and the stepped silicon nanostructure array can be used as a connection structure for multi-layer wiring to achieve signal transmission and interconnection between different layers, thereby improving the integration and performance of the circuit.

[0112] In another specific embodiment, the semiconductor device is a biosensor, and the stepped silicon nanostructure is further surface modified to immobilize biological molecules such as antibodies and enzymes on its surface, thereby constructing a highly sensitive biosensor.

[0113] In another specific embodiment, the semiconductor device is an electrode of a lithium-ion battery or a supercapacitor. The stepped silicon nanostructure can alleviate the volume expansion problem of the battery during the charging and discharging process and improve the cycle stability of the battery. At the same time, due to the high specific surface area of ​​the stepped silicon nanostructure, it can quickly store and release charges, thereby improving the performance of the lithium-ion battery or supercapacitor.

[0114] It should be noted that, in addition to etching nanostructure arrays / stepped nanostructure arrays of semiconductor materials, the wet etching device provided in the embodiment of the present invention can also be used for wet etching experiments and processes of other materials or structures, such as metal layer etching, photomask manufacturing, glass processing, etc.; the specific patterns and structures etched are not limited to nanopores and nanogrooves, but can also be various patterns or structures that require wet etching to prepare, such as microelectrodes, microchannels, pyramid structures, and suspended structures; in these experiments and processes, the required number of processing modules is selected and the processing modules are arranged and combined, the corresponding etching solution is added to the etching container of each processing module, and then the corresponding computer program is input to control the etching process through the control module, so as to realize automated wet etching.

[0115] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A wet etching device, characterized in that: The invention comprises a processing module, wherein the processing module comprises: A housing is formed with a receiving cavity; a surface of the housing is provided with a direct-acting groove in a vertical direction; a horizontally penetrating gap is left between the top of the direct-acting groove and the top of the housing, and the gap forms a lateral motion channel; An etching container is provided on the same surface of the housing as the direct-acting groove and is located below the direct-acting groove; the etching container is used to contain an etching solution; A movable loader for loading the device to be processed; A direct-acting unit is disposed in the accommodating cavity; the direct-acting unit is connected to the movable loader and is used to control the movable loader to rise and fall along the direct-acting groove so that the device to be processed is immersed in or leaves the etching solution; A traverse unit is arranged in the accommodating cavity; the traverse unit is connected to the movable loader and is used to control the movable loader to move laterally along the traverse channel.

2. The wet etching device according to claim 1, characterized in that: The direct-acting unit comprises a direct-acting motor, a direct-acting gear and a direct-acting rack; The direct-acting rack is arranged in a vertical direction and meshes with the direct-acting gear; The direct-acting motor is used to drive the direct-acting gear to rotate so that the direct-acting rack moves in a vertical direction, and the direct-acting rack drives the movable loader to move up and down.

3. The wet etching device according to claim 2, characterized in that: The traverse unit comprises a traverse motor, a traverse gear, a traverse gear shaft and a traverse rack; The traverse rack is arranged in the horizontal direction; the traverse rack is fixedly connected to the movable loader and can be meshed with the traverse gear; The traverse motor drives the traverse gear to rotate via the traverse gear shaft, so that the traverse rack meshing with the traverse gear moves laterally, thereby driving the movable loader to move laterally.

4. The wet etching device according to claim 1, characterized in that: The processing module is also provided with a connecting groove; Any one of the plurality of processing modules is detachably connected to another one at the connection groove via a fastener; The traverse unit controls the lateral movement of the movable loader so that the movable loader is transferred from one processing module to another processing module.

5. The wet etching device according to any one of claims 3, characterized in that: Also includes a control module; The control module includes a memory and a processor; The memory is used to store a computer program; the processor executes the computer program to control the operation of the linear motor and the traverse motor.

6. A nanostructure array etching method, characterized in that: Using the wet etching device according to any one of claims 1 to 5, the method comprises the following steps: S1, preparing a photoresist nanopore mask and a noble metal layer on the surface of the device to be processed; S2, adding an etching solution into an etching container of the wet etching device, and loading a device to be processed onto a movable loader of the wet etching device; S3, immersing the movable loader into the etching solution and setting the etching time; S4, etching is completed, and the movable loader is raised until the device to be processed is completely out of the etching solution.

7. The method according to claim 6, characterized in that The wet etching device includes a plurality of processing modules, namely a first processing module, a second processing module and a third processing module. Step S2 of the method specifically includes: Adding a first etching solution, a second etching solution, and a third etching solution into etching containers of the first processing module, the second processing module, and the third processing module, respectively; The first etching solution is used to axially etch the device to be processed under the catalysis of the precious metal layer to obtain a first step hole segment; the second etching solution is used to radially etch the first step hole segment to expand the diameter of the first step hole segment; the third etching solution is used to axially etch the device to be processed from the bottom of the first step hole segment under the catalysis of the precious metal layer to obtain a second step hole segment.

8. The method according to claim 7, characterized in that The first processing module, the second processing module and the third processing module are used in sequence to etch the device to be processed, and the step S3 and the step S4 are performed when any one of the first processing module, the second processing module and the third processing module is used.

9. The method according to any one of claims 6 to 8, characterized in that The material of the device to be processed is at least one of silicon, gallium arsenide, and silicon carbide.

10. A semiconductor device having a stepped nanostructure array, characterized in that: The stepped nanostructure array is prepared by the wet etching device described in any one of claims 1-5, or by the nanostructure array etching processing method described in any one of claims 6-9.

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