Low-energy electron emission device and micro-area chemical reaction processing method

Abstract

The invention discloses a low-energy electron emission device and a micro-area chemical reaction processing method, and relates to the technical field of micro-area chemistry. The gas supply pipeline is used for introducing reaction gas; the feed air passage is in threaded connection in the air supply pipeline and comprises a hollow pipe, micropores are formed in the top surface and the bottom surface of the hollow pipe, and a connecting line of the micropores in the top surface and the bottom surface faces the center of the bottom surface, so that micro-airflow supply is realized; the conductive needle point penetrates through the bottom surface of the hollow tube, is connected with the negative electrode of the power supply and is used for adjusting bias voltage and realizing low-energy electron emission; the sample table is positioned below the conductive needle point, is used for placing a sample and is connected with a power supply anode and a power supply cathode connected with the conductive needle point to form a closed loop; the precise operation and control table is used for placing the sample table and accurately adjusting the position of the sample by adjusting the position of the sample table; the gas supply pipeline, the feed gas circuit, the conductive needle tip, the sample table and the precise operation and control table are coaxially arranged. The method is high in machining precision and suitable for batch production requirements.

Description

Technical Field

[0001] This invention relates to the field of micro-area chemistry technology, specifically to a low-energy electron emission device and a low-energy electron-induced micro-area chemical reaction processing method. Background Technology

[0002] In existing technologies, micro-area chemical reaction processing methods mainly include laser processing, focused ion beam (FIB) processing, and focused electron-beam-induced processing (FEBIP) processing. However, laser processing, which utilizes the thermal or photochemical effects of a laser beam to etch or deposit materials, has inherent drawbacks: the focusing limit of the laser beam is limited by diffraction, resulting in processing precision mostly at the micrometer level, which is insufficient for nanometer-scale requirements; the heat-affected zone is relatively large, easily leading to sample lattice distortion and performance degradation; and the controllability of additive processing is poor, making it difficult to form complex micro / nano structures. Focused ion beam (FIB) processing, on the other hand, uses a focused high-energy ion beam (such as Ga...) + Ions (typically with energies of 10-100 keV) bombard the sample surface to achieve sputtering etching (subtractive) or ion-induced deposition (additive). While this method can achieve nanoscale precision, it has significant drawbacks: high-energy ion bombardment can cause lattice damage and ion implantation contamination on the sample surface; the processing rate is extremely low, and additive processing suffers from low deposition efficiency and poor material purity; it is only suitable for small-area fine processing and cannot meet the needs of mass production. Focused electron-beam-induced processing (FEBIP) uses a high-energy electron beam (typically with energies of 1-30 keV) to induce a reaction between gas and the sample surface to achieve processing. However, the core problem with existing FEB technology is that excessively high electron energy can easily lead to charge accumulation and localized overheating on the sample surface, and insufficient control over the gas in micro-areas—the reactant gas tends to diffuse inside the vacuum chamber, failing to form a localized reaction atmosphere, resulting in decreased processing resolution and poor reaction selectivity, making it difficult to simultaneously meet the high precision requirements of additive and subtractive processing.

[0003] Therefore, those skilled in the art are dedicated to providing a micro-area chemical reaction processing method with high processing precision that is suitable for mass production needs. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a micro-area chemical reaction processing method with high processing accuracy and suitable for mass production needs.

[0005] To achieve the above-mentioned technical objectives, the present invention mainly adopts the following technical solutions: This invention discloses a low-energy electron emission device, comprising: Gas supply line: used to introduce reaction gases; Feed air passage: threaded connection inside the air supply pipeline, including a hollow tube, the top and bottom surfaces of the hollow tube are provided with micropores, and the connecting line of the micropores on the top and bottom surfaces is set towards the center of the bottom surface to realize micro airflow supply; Conductive needle tip: inserted through the bottom surface of the hollow tube and connected to the negative terminal of the power supply, used to adjust the bias voltage and realize low-energy electron emission; Sample stage: Located below the conductive needle tip, it is used to place the sample, connects to the positive terminal of the power supply, and forms a closed circuit with the negative terminal of the power supply connected to the conductive needle tip; Precision motion control stage: Used to place the sample stage, and the position of the sample can be precisely adjusted by adjusting the position of the sample stage; The gas supply line, the gas feed line, the conductive needle tip, the sample stage, and the precision motion control table are arranged coaxially.

[0006] In a preferred embodiment of the present invention, a one-way valve is also connected to the side of the gas supply pipeline.

[0007] In a preferred embodiment of the present invention, the angle between the micro-hole connecting line of the top and bottom surfaces and the end of the conductive needle tip is 10-30°, the conductive needle tip has a length of 1 μm to 1 cm, a diameter of 100 nm to 500 μm, and a tip size of less than 2 nm.

[0008] In a preferred embodiment of the present invention, a flow controller and a pressure sensor are also provided in the gas supply pipeline.

[0009] In a preferred embodiment of the present invention, a vacuum chamber is also included, and the gas supply line, the gas feed line, the conductive needle tip, the sample stage, and the precision motion control stage are all disposed in the vacuum chamber.

[0010] Preferably, the vacuum level of the vacuum chamber is 10. - ³~10 -6 Pa.

[0011] In a preferred embodiment of the present invention, a controller is also included, which is electrically connected to the gas supply line, the power supply, the precision motion control console, and the one-way valve.

[0012] This invention also discloses a low-energy electron-induced micro-region chemical reaction processing method, which employs the low-energy electron emission device described above and includes the following steps: Step 1: Fix the sample to be processed on the sample stage, place it in the vacuum chamber, start the vacuum pumping unit, and pump the vacuum chamber pressure to 10. - ³~10 -6 Pa; Step 2: Select the reaction gas according to the processing type, and deliver the reaction gas through the gas supply pipeline to form a local micro-area gas atmosphere centered on the sample to be processed area; Step 3: Turn on the power supply and focus the electron beam onto the sample to be processed area through the micro-hole. Scan along the preset trajectory, and the low-energy electron beam induces a reaction with the reactive gas. Step 4: After processing, stop electron beam irradiation and gas delivery, continue evacuating for 30-60 minutes to remove residual gas, then fill the vacuum chamber with inert gas to atmospheric pressure and remove the sample.

[0013] In a preferred embodiment of the present invention, in step 2, when additive processing is performed using a deposition method, the reaction gas is selected from any one of methane, acetylene, silane, and chromium hexacarbonyl; when subtractive processing is performed using an etching method, the reaction gas is selected from any one of oxygen, sulfur hexafluoride, and chlorine.

[0014] In a preferred embodiment of the present invention, in step 3, the electron beam energy adjustment step is 0.1 eV and the beam current adjustment step is 0.1 nA.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Nanoscale high-precision machining: The conductive needle tip of the electron emission device of this invention has an atomic-level tip size and uses a low-energy electron beam below 100 eV. Combined with micro-area control of coaxial gas supply, it can achieve high-resolution fine structure machining with a machining resolution ≤10 nm, which far exceeds the actual effective precision of traditional laser machining and FIB / FEB machining.

[0016] 2. Near-zero sample damage: The emitted electron energy of this invention is ≤100 eV, which is far below the lattice damage threshold of most materials (silicon, metals, polymers) (usually ≥500 eV). This completely avoids problems such as lattice distortion, ion implantation, and charge accumulation caused by high-energy ions / electrons, and is especially suitable for processing samples that are sensitive to damage, such as semiconductor devices, flexible materials, and biochips.

[0017] 3. High controllability of micro-area reaction: This invention coaxially sets up the gas supply line, feed gas path, conductive needle tip, sample stage, and precision motion control stage, which can realize the micro-area confinement of the reaction gas, with a small gas diffusion range. This avoids contamination of non-processing areas or blurring of processing edges caused by the diffusion of reaction gas in the vacuum chamber. The gas delivery is directly aimed at the processing area, resulting in high utilization of reaction gas, reducing gas waste, and at the same time reducing the impact of residual gas inside the vacuum chamber on processing, thus improving reaction selectivity (the reaction occurs only in the processing area, with no significant impact on non-processing areas). 4. Compatible with additive and subtractive processing: By changing the type of reaction gas, additive deposition (carbon-based, silicon-based, metal, metal oxide and other materials) and subtractive etching (silicon, metal, polymer, oxide and other materials) can be flexibly realized, which is suitable for the integrated processing of complex micro and nano structures.

[0018] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0019] Figure 1 A schematic diagram of the low-energy electron emission device provided by the present invention; In the diagram, 1 is a one-way valve, 2 is a conductive needle tip, 3 is a sample stage, 4 is a precision motion control console, 5 is a gas supply line, and 6 is a feeder gas path. Detailed Implementation

[0020] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0021] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0022] The core technical solution of this invention is: by utilizing the low-damage characteristics of low-energy electrons below 100 eV, combined with the local micro-region gas atmosphere formed by coaxial gas supply, selective chemical reactions are induced between the reaction gas and the sample surface, thereby achieving precise addition / subtraction processing.

[0023] The following is a description through specific embodiments.

[0024] Example 1

[0025] like Figure 1 The low-energy electron emission device shown includes: Gas supply line 5: used to introduce reaction gas; as the fixed end at the top of the electron emission source, the reaction raw materials and protective gas are introduced through the gas supply line 5, and finally the gas reaches the electron beam action area through the micro-hole at the end of the emission device. At the same time, it is equipped with a high-precision flow controller and pressure sensor, which can be dynamically adjusted according to the processing area.

[0026] In this invention, a one-way valve 1 is also connected to the side of the gas supply line 5 to prevent excessive pressure.

[0027] The air supply path 6 is threadedly connected to the air supply line 5, specifically including a hollow tube with external threads, which can be directly and simply threadedly connected to the end of the air supply line 5. The top and bottom surfaces of the hollow tube are provided with micro-holes, and the connecting line of the micro-holes on the top and bottom surfaces is set towards the center of the bottom surface to form an angle. In this invention, the angle between the connecting line of the micro-holes on the top and bottom surfaces and the end of the conductive needle tip 2 is 15° to achieve micro-airflow supply. Conductive tip 2: Inserted into the bottom surface of the hollow tube, its tip length is 3 mm, its diameter is 300 μm, its tip size is less than 2 nm, and it is connected to the negative terminal of the power supply to adjust the bias voltage and realize low-energy electron emission. Sample stage 3: Located below conductive needle tip 2, it is used to place the sample, connects to the positive terminal of the power supply, and forms a closed circuit with the negative terminal of the power supply connected to conductive needle tip 2; Precision control stage 4: Used to place sample stage 3, and the position of the sample can be precisely adjusted by adjusting the position of sample stage 3; Among them, the above-mentioned gas supply line 5, feed gas line 6, conductive needle tip 2, sample stage 3, and precision motion control table 4 are coaxially arranged. Vacuum chamber: Equipped with molecular pumps and mechanical pumps, achieving a vacuum level of up to 10. - ³~10 -6 Pa; the gas supply line 5, the gas feed line 6, the conductive needle tip 2, the sample stage 3, and the precision motion control table 4 are all located inside the vacuum chamber. Controller: Electrically connected to the gas supply line, power supply, precision motion control table and one-way valve, supports preset processing trajectory, and can dynamically adjust electron beam energy, beam current, focusing position, and pressure and flow rate of reaction gas to achieve automated and high-precision control of the processing process.

[0028] Example 2

[0029] A low-energy electron-induced micro-area chemical reaction processing method, using the aforementioned low-energy electron emission device, includes the following steps: 1. Sample preparation and vacuum environment setup: The sample to be processed (such as silicon wafer, metal thin film, semiconductor device, flexible substrate) is fixed on the sample stage of the micro-area positioning system and placed in the vacuum chamber; the vacuum pumping unit is activated to pump the vacuum chamber pressure to 10. - ³~10 -6 Pa.

[0030] 2. Micro-area gas atmosphere construction: Select the reaction gas according to the processing type: Additive processing (deposition): Materials such as methane, acetylene, silane, and hexacarbonyl chromium are selected. Subtractive processing (etching): Select gases such as oxygen (oxidative etching), sulfur hexafluoride (fluoride etching), and chlorine (chlorination etching); transport the reaction gas through a coaxial gas supply structure to form a local micro-area gas atmosphere centered on the sample to be processed area.

[0031] 4. Low-energy electron beam induced reaction: The low-energy electron source is activated, and the electron beam is focused onto the sample to be processed area through the focusing unit and scanned along the preset trajectory; the low-energy electron beam induces a reaction with the reaction gas.

[0032] 5. Parameter adjustment: Electron beam parameters: energy (adjustment step 0.1 eV), beam current (adjustment step 0.1 nA), focusing position; Gas parameters: Reaction gas pressure 10 -4 Pa, flow rate 20 sccm; 6. Processing Completion and Sample Removal: After processing is completed, stop electron beam irradiation and gas delivery, continue evacuation for 30-60 minutes to remove residual gas, then fill the vacuum chamber with inert gas to atmospheric pressure and remove the sample.

[0033] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A low-energy electron emission device, characterized in that, include: Gas supply line: used to introduce reaction gases; Feed air passage: threaded connection inside the air supply pipeline, including a hollow tube, the top and bottom surfaces of the hollow tube are provided with micropores, and the connecting line of the micropores on the top and bottom surfaces is set towards the center of the bottom surface to realize micro airflow supply; Conductive needle tip: inserted through the bottom surface of the hollow tube and connected to the negative terminal of the power supply, used to adjust the bias voltage and realize low-energy electron emission; Sample stage: Located below the conductive needle tip, it is used to place the sample, connects to the positive terminal of the power supply, and forms a closed circuit with the negative terminal of the power supply connected to the conductive needle tip; Precision motion control stage: Used to place the sample stage, and the position of the sample can be precisely adjusted by adjusting the position of the sample stage; The gas supply line, the gas feed line, the conductive needle tip, the sample stage, and the precision motion control table are arranged coaxially.

2. The low-energy electron emission device according to claim 1, characterized in that, A one-way valve is also connected to the side of the gas supply pipeline.

3. The low-energy electron emission device according to claim 1, characterized in that, The angle between the connecting line of the micropores on the top and bottom surfaces and the end of the conductive needle tip is 10-30°. The conductive needle tip has a length of 1 μm to 1 cm, a diameter of 100 nm to 500 μm, and a tip size of less than 2 nm.

4. The low-energy electron emission device according to claim 1, characterized in that, The gas supply pipeline is also equipped with a flow controller and a pressure sensor.

5. The low-energy electron emission device according to claim 1, characterized in that, It also includes a vacuum chamber, in which the gas supply line, the gas feed line, the conductive needle tip, the sample stage, and the precision motion control stage are all located.

6. The low-energy electron emission device according to claim 5, characterized in that, The vacuum level of the vacuum chamber is 10. - ³~10 -6 Pa.

7. The low-energy electron emission device according to claim 1, characterized in that, It also includes a controller that is electrically connected to the gas supply line, power supply, precision motion control console and check valve.

8. A low-energy electron-induced micro-region chemical reaction processing method, characterized in that, The low-energy electron emission device as described in any one of claims 1-7 comprises the following steps: Step 1: Fix the sample to be processed on the sample stage, place it in the vacuum chamber, start the vacuum pumping unit, and pump the vacuum chamber pressure to 10. - ³~10 -6 Pa; Step 2: Select the reaction gas according to the processing type, and deliver the reaction gas through the gas supply pipeline to form a local micro-area gas atmosphere centered on the sample to be processed area; Step 3: Turn on the power supply and focus the electron beam onto the sample to be processed area through the micro-hole. Scan along the preset trajectory, and the low-energy electron beam induces a reaction with the reactive gas. Step 4: After processing, stop electron beam irradiation and gas delivery, continue evacuating for 30-60 minutes to remove residual gas, then fill the vacuum chamber with inert gas to atmospheric pressure and remove the sample.

9. The processing method according to claim 8, characterized in that, In step 2, when additive processing is performed using the deposition method, the reaction gas is selected from any one of methane, acetylene, silane, and chromium hexacarbonyl; when subtractive processing is performed using the etching method, the reaction gas is selected from any one of oxygen, sulfur hexafluoride, and chlorine.

10. The processing method according to claim 8, characterized in that, In step 3, the electron beam energy adjustment step is 0.1 eV, and the beam current adjustment step is 0.1 nA.

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