WO2023045101A1 - Sic semiconductor dry surface treatment device and method - Google Patents

Sic semiconductor dry surface treatment device and method Download PDF

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Publication number
WO2023045101A1
WO2023045101A1 PCT/CN2021/136781 CN2021136781W WO2023045101A1 WO 2023045101 A1 WO2023045101 A1 WO 2023045101A1 CN 2021136781 W CN2021136781 W CN 2021136781W WO 2023045101 A1 WO2023045101 A1 WO 2023045101A1
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reaction chamber
gas
vacuum reaction
vacuum
ecr plasma
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PCT/CN2021/136781
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French (fr)
Chinese (zh)
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王德君
秦福文
尉升升
尹志鹏
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大连理工大学
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Publication of WO2023045101A1 publication Critical patent/WO2023045101A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32192—Microwave generated discharge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32431—Constructional details of the reactor
    • H01J37/3244—Gas supply means
    • H01J37/32449—Gas control, e.g. control of the gas flow
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32431—Constructional details of the reactor
    • H01J37/32458—Vessel
    • H01J37/32477—Vessel characterised by the means for protecting vessels or internal parts, e.g. coatings
    • H01J37/32495—Means for protecting the vessel against plasma
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32917—Plasma diagnostics
    • H01J37/32935—Monitoring and controlling tubes by information coming from the object and/or discharge
    • H01J37/32981—Gas analysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/0445—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising crystalline silicon carbide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/0445—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising crystalline silicon carbide
    • H01L21/045—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising crystalline silicon carbide passivating silicon carbide surfaces
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/32—Processing objects by plasma generation
    • H01J2237/33—Processing objects by plasma generation characterised by the type of processing
    • H01J2237/335—Cleaning

Definitions

  • the invention relates to a SiC semiconductor dry surface treatment device and method, belonging to the technical field of semiconductor surface cleaning and passivation.
  • SiC silicon carbide
  • SiC is one of the wide-bandgap semiconductor hotspot materials. It has the advantages of high critical breakdown electric field and high thermal conductivity, and has important applications in the field of high-voltage and high-temperature power devices.
  • SiC is also a preferred substrate for epitaxial growth of materials such as graphene and gallium nitride.
  • SiC semiconductors still have outstanding new problems such as carbon residues, silicon dangling bonds, ion contamination, and surface contamination after conventional wet cleaning.
  • surface defects are likely to be Interface defects or fixed charges exist at the interface of the device to capture or emit electrons, thereby affecting the threshold voltage drift and reliability of the device; on the other hand, the defect state on the SiC surface will affect the contact characteristics of the metal and semiconductor, thereby affecting the SiC Device efficiency and switching speed and other performance.
  • the atomic structure and morphology of the SiC surface directly determine the crystal structure and film quality of the epitaxially grown material.
  • Liu Bingbing [Application No.: 201510735852.X] proposed to use the ECR microwave plasma system to generate hydrogen-nitrogen mixed plasma to clean the SiC surface, which can significantly reduce the surface state density, effectively inhibit the generation of interface defect states during the oxidation process, and improve the oxidation film. breakdown characteristics.
  • the existing equipment and methods described provide technical support for SiC surface treatment, the equipment and methods also have the following disadvantages: the plasma coverage area generated by a single plasma source is limited, and the density at the edge of the plasma source is low , the surface treatment effect cannot meet the surface treatment requirements of 6-inch or larger SiC wafers at this stage; the metal on the inner wall of the equipment is easily bombarded by plasma, and the metal ions generated will contaminate the SiC wafer surface.
  • the presence of moving ions seriously affects device performance; the gas used in the surface treatment process cannot be precisely regulated, and it is easy to damage the surface of the SiC wafer by plasma, which affects the atomic arrangement and structure of the SiC surface.
  • the purpose of the present invention is to provide a SiC semiconductor dry surface treatment equipment and method.
  • the invention can be single dry surface cleaning, or dry surface cleaning followed by dry surface passivation treatment, so as to adapt to the early surface treatment requirements of SiC device ohmic contact process and gate oxide layer preparation process.
  • the present invention uses dual ECR plasma sources as the plasma generating device, and adjusts the plasma coverage area by changing the angle between the central axes of the two ECR sources, which can meet the dry surface treatment requirements of 6-inch SiC wafers.
  • the dual ECR plasma sources The superimposition of edge plasmas improves the disadvantages of small plasma uniform area and low plasma density produced by a single plasma source;
  • the purpose of the shielding barrel of quartz or borosilicate glass is to shield the bombardment of the plasma on the metal wall, so as to reduce the pollution of metal particles to the SiC surface; the aluminum foil pendant with passivation coating and quartz or borosilicate glass
  • the trace nitrogen and boron elements produced by the shielding barrel after plasma bombardment also have a beneficial effect on the passivation of SiC surface defects, and the aluminum foil pendant with passivation coating and the shielding barrel of quartz or borosilicate glass are easy to replace , low price and other advantages.
  • the equipment proposed in the present invention is also equipped with a residual gas analyzer. Through real-time monitoring of the gas composition in the vacuum reaction chamber, the gas flow rate and component distribution ratio during the surface treatment process can be precisely regulated in situ to achieve optimal surface treatment. processing effect.
  • the technical solution adopted by the present invention is: a treatment method for SiC semiconductor dry surface treatment equipment, the treatment equipment includes a double ECR plasma supply device, Vacuum reaction chamber, sample loading chamber, residual gas analyzer, gas distribution device and gas distribution system, the first and second ECR plasma sources, microwave sources and waveguides of the same size are arranged above the vacuum reaction chamber, and the waveguide is set
  • the first and second microwave coupling antennas together constitute a dual ECR plasma supply device;
  • the top of the vacuum reaction chamber is provided with a Faraday cup, an air inlet, a first vacuum gauge, an electronic probe and a first tungsten halogen lamp, and all
  • a sample stage with an electric heating device is set inside the vacuum reaction chamber, wherein the electron probe is used to accurately measure and control the electron density and temperature of the ECR plasma of the sample stage, and the Faraday cylinder is used to accurately measure and control the ion density of the ECR plasma of the sample stage and temperature;
  • Vacuum equipment is connected, and the vacuum reaction chamber is also equipped with a CCD imaging system, a magnetic manipulator, an observation window and a reflection high-energy electron diffractometer.
  • the metal inner wall of the vacuum reaction chamber is covered with coated aluminum foil.
  • the diameter of the barrel is 180-240 mm, the height is 50-120 mm, the material of the shielding barrel is selected from one of quartz or borosilicate glass;
  • the thickness of coated aluminum foil is 10-100 ⁇ m, both sides of the aluminum foil are covered with 5-20 nm aluminum oxide film, and the aluminum oxide surface is covered with a coating, the coating thickness is 0.5-2 ⁇ m, and the coating is selected from one of silicon oxide film, silicon nitride film, silicon nitride oxide film, and boron nitride film Or a combination of silicon oxide film, silicon nitride film, silicon oxynitride film, and boron nitride film; a shielding barrel of quartz or borosilicate glass is
  • the sample loading chamber is provided with the second halogen tungsten lamp, the second vacuum gauge and the deflation Valve;
  • the gas distribution system includes the first and second quartz cups arranged inside the first and second ECR plasma sources, and the air inlets are respectively connected to the gas supply ring pipelines in the first and second quartz cups to participate in microwave plasma body discharge;
  • the gas distribution device includes a residual gas analyzer arranged on one side of the vacuum reaction chamber and connected to a computer information acquisition controller, and the computer information acquisition controller is also connected to 6 gas flow controllers respectively, and the 6 gas flow controllers are respectively connected to each other.
  • the sources are respectively connected to the input ends of the 6-way gas flow controllers through 6 pressure reducing valves, the output ends of the 6-way gas flow controllers are all connected to the input ends of the gas mixing chamber, and the output ends of the gas mixing chamber are connected to the air inlet through a vacuum stop valve ;
  • processing method comprises the following steps:
  • Step 1 Vacuum the sample loading room, put the sample into the sample loading room, turn on the vacuum equipment to evacuate the sample loading room to 10 -4 -10 -7 Pa, open the gap between the sample loading room and the vacuum reaction chamber Gate valve, the sample is sent to the sample stage of the vacuum reaction chamber, and the gate valve is closed;
  • Step 2 vacuumize the vacuum reaction chamber, turn on the vacuum equipment, and vacuumize the vacuum reaction chamber to make the vacuum degree reach 10 -5 -10 -7 Pa;
  • Step 3 Clean the surface of the SiC wafer.
  • start the gas distribution system and pass the gas required for cleaning into the vacuum reaction chamber.
  • the gas used is argon or hydrogen, and the gas flow is set to 0-100 sccm, adjust the angle between the central axes of the first and second ECR plasma sources to be 0-45 degrees, set the microwave power to 300-2000 W, adjust the air pressure in the vacuum reaction chamber 2 to 0.5-2 Pa, and the cleaning time is 1- After 20 minutes, the SiC wafer surface was cleaned.
  • the residual gas analyzer in the gas distribution system monitored the gas components in the vacuum reaction chamber in real time, and the monitoring results were fed back to the computer information acquisition controller. Control the gas flow controllers of each gas path to achieve precise regulation of the gas flow and ratio in the vacuum reaction chamber;
  • Step 4 Passivate the surface of the SiC wafer.
  • the gas is one of hydrogen, nitrogen, hydrogen chloride, chlorine, ammonia or hydrogen, nitrogen, hydrogen chloride, chlorine,
  • the gas combination of ammonia gas, the gas flow rate of each gas path is set to 0-100 sccm, the angle between the central axis of the first and second ECR plasma sources is adjusted to 0-45 degrees, the microwave power is set to 300-2000 W, and the vacuum
  • the air pressure in the reaction chamber is adjusted to 0.5-2 Pa, the passivation treatment time is 1-20 min, and the passivation treatment is carried out on the surface of the SiC wafer.
  • the residual gas analyzer in the gas distribution system monitors the various gas components in the vacuum reaction chamber in real time. The monitoring results are fed back to the computer information acquisition controller, and then the gas flow controllers of each gas circuit are controlled to realize the precise regulation of the gas flow and proportion in the vacuum reaction chamber;
  • Step 5 The surface treatment of the SiC wafer is completed. After the surface treatment of the SiC wafer is completed, the sample is taken out after the temperature drops to room temperature.
  • a SiC semiconductor dry surface treatment equipment and method wherein the treatment equipment includes a double ECR plasma supply device, a vacuum reaction chamber, a sample loading chamber, a residual gas analyzer, a gas distribution device and a gas distribution system.
  • the processing method includes the following steps: (1) vacuumize the sample loading chamber, (2) vacuumize the vacuum reaction chamber, (3) clean the surface of the SiC wafer, (4) passivate the surface of the SiC wafer Chemical treatment, (5) SiC wafer surface treatment is completed.
  • the present invention uses dual ECR plasma sources as the plasma generating device, and adjusts the plasma coverage area by changing the angle between the central axes of the two ECR sources, which can meet the dry cleaning requirements of 6-inch SiC wafers , the superimposition of the edge plasma of the double ECR plasma source improves the disadvantages of the small size of the plasma uniform area and the low plasma density generated by the single plasma source;
  • the metal inner wall of the vacuum reaction chamber is covered with an aluminum foil pendant with a passivation coating
  • the purpose of the shielding barrel of quartz or borosilicate glass set around the sample stage is to shield the plasma from bombarding the metal wall, so as to reduce the pollution of metal particles to the SiC surface;
  • the trace nitrogen and boron elements produced by the shielding barrel of quartz or borosilicate glass after plasma bombardment also have a beneficial effect on the passivation of SiC surface defects, and the aluminum foil pendant with passivation coating and quartz or borosilicate glass
  • Fig. 1 is a top view of a SiC semiconductor dry surface treatment equipment according to the present invention.
  • Microwave source 2. Vacuum reaction chamber, 2a, Faraday cup, 2b, air inlet, 2c, first vacuum gauge, 2d, electronic probe, 2e, first tungsten halogen lamp, 3, Waveguide, 3a, the first microwave coupling antenna, 3b, the second microwave coupling antenna, 4, the first ECR plasma source, 4a, the second ECR plasma source, 5, the first quartz cup, 5a, the second quartz cup, 6 , Sample chamber, 6a, the second tungsten halogen lamp, 6b, the second vacuum gauge, 6c, air release valve, 7, gate valve, 8, CCD imaging system, 9, vacuum equipment, 10, magnetic Manipulator, 11. Observation window, 12. Residual gas analyzer, 13. Reflection high energy electron diffractometer.
  • Fig. 2 is a cross-sectional view of Fig. 1 when the double ECR plasma source of the present invention is placed vertically.
  • bellows 15, permanent magnet ring, 16, coated aluminum foil, 17, shielding barrel, 18, sample stage, 19, heating device, 20, gas supply ring pipeline.
  • Fig. 3 is a cross-sectional view of Fig. 1 when the central axis of the dual ECR plasma source of the present invention is placed at an angle of 45 degrees.
  • Fig. 4 is a schematic diagram of the gas distribution device of the present invention.
  • gas mixing chamber 22, vacuum stop valve, 23, computer information acquisition controller, 24, pressure reducing valve, 25, gas flow controller (MFC).
  • MFC gas flow controller
  • Fig. 5 is a flowchart of the method steps of the present invention.
  • a SiC semiconductor dry surface treatment equipment includes a double ECR plasma supply device, a vacuum reaction chamber 2, a sample loading chamber 6, a residual gas analyzer 12, a gas distribution device and Gas distribution system, the first and second ECR plasma sources 4, 4a, microwave source 1 and waveguide 3 of the same size are arranged above the vacuum reaction chamber 2, and the waveguide 3 is provided with the first and second microwave coupling antennas 3a, 3b together constitute a double ECR plasma supply device; the top of the vacuum reaction chamber 2 is provided with a Faraday cup 2a, an air inlet 2b, a first vacuum gauge 2c, an electronic probe 2d and a first tungsten halogen lamp 2e, the A sample stage 18 with a heating device 19 is arranged inside the vacuum reaction chamber 2, wherein the electron probe 2d is used to accurately measure and control the electron density and temperature of the ECR plasma of the sample stage 18, and the Faraday cage 2a is used to precisely measure and control the ECR of the sample stage 18.
  • the interface flanges of the first and second ECR plasma sources 4 and 4a are all fixed on the bellows 14, and the angle between the central axes of the first and second ECR plasma sources can be 0-45 degrees, when the central axis angle is 45 degrees, the axes of the first and second ECR plasma sources 4 and 4a are all facing the center of the sample stage 18, and the high quality of wafers of different sizes can be satisfied by adjusting the central axis angle Cleaning, in addition, the bottom of the vacuum reaction chamber 2 is connected to the vacuum equipment 9 through pipelines, the vacuum reaction chamber 2 is also provided with a CCD imaging system 8, a magnetic manipulator 10, an observation window 11 and a reflection high-energy electron diffractometer 13, the vacuum reaction chamber The surface of the metal inner wall of 2 is covered with coated aluminum foil 16, and a shielding barrel 17 is arranged around the sample stage 18.
  • the diameter of the shielding barrel 17 is 180-240 mm, and the height is 50-120 mm. mm, the material of the shielding barrel 17 is selected from one of quartz or borosilicate glass; the thickness of the coated aluminum foil 16 is 10-100 ⁇ m, and the surface of both sides is covered with a 5-20 nm aluminum oxide film, and the oxide The aluminum surface is covered with a coating with a coating thickness of 0.5-2 ⁇ m, the coating is selected from one of silicon oxide film, silicon nitride film, silicon nitride oxide film, boron nitride film or a combination of silicon oxide film, silicon nitride film, silicon nitride oxide film, boron nitride film;
  • a shielding barrel 17 of quartz or borosilicate glass is arranged around the sample stage 18, which is used to shield the bombardment of the plasma on the metal wall, so as to reduce the pollution of metal ions to the SiC surface, and aluminum foil and quartz or The shielding barrel 17 of borosi
  • the first and second quartz cups 5 and 5a inside the 2ECR plasma source 4 and 4a, and the gas inlet 2b are respectively connected to the gas supply ring pipeline 20 in the first and second quartz cups 5 and 5a to participate in the microwave plasma Discharge;
  • the gas distribution device includes a residual gas analyzer 12 arranged on one side of the vacuum reaction chamber and connected to a computer information collection controller 23, and the computer information collection controller 23 is also connected to 6 gas flow controllers 25 respectively , the 6 gas sources are respectively connected to the input ends of the 6 gas flow controllers 25 through 6 pressure reducing valves 24, the output ends of the 6 gas flow controllers 25 are all connected to the input ends of the gas mixing chamber 21, and the output ends of the gas mixing chamber 21 It is connected to the air inlet 2b through a vacuum stop valve 22 .
  • the two ECR plasma sources are placed vertically, that is, the angle ⁇ between the central axes of the two ECR plasma sources is 0 degrees; the diameter of the quartz shielding barrel 17 arranged around the sample stage 18 is 220 mm, and the height 60 mm, the metal inner wall surface of the vacuum reaction chamber 2 is covered with aluminum foil with silicon oxide coating, the thickness of the aluminum foil is 50 ⁇ m, the aluminum oxide on both sides of the aluminum foil is 20 nm, and the silicon oxide coating on the aluminum oxide surface The thickness is 1.5 ⁇ m.
  • the cleaning steps are as follows:
  • Step 1 Put a 6-inch SiC wafer into the sample loading chamber 6, turn on the vacuum equipment 9 to evacuate the sample loading chamber 6 to 10 -5 Pa, and open the gate valve 7 between the sample loading chamber 6 and the vacuum reaction chamber 2 , and then send the 6-inch SiC wafer to the sample stage 18 of the vacuum reaction chamber 2, and close the gate valve 7;
  • Step 2 turn on the vacuuming device 9, and vacuumize the vacuum reaction chamber 2 to make the vacuum degree reach 10 -6 Pa;
  • Step 3 Set the temperature of the sample stage 18 to 400°C.
  • start the gas distribution system and feed hydrogen gas wherein the flow rate of hydrogen gas is 60 sccm, and adjust the first and second ECR plasma sources 4 and 4a
  • the included angle of the central axis is 0 degrees
  • the microwave power is set to 700 W
  • the air pressure in the vacuum reaction chamber 2 is adjusted to 1 Pa
  • the cleaning time is 5 min;
  • Step 4 After cleaning, wait for the temperature to drop to room temperature and take out the sample;
  • the device for dry surface treatment of a semiconductor provided by the present invention can be realized by controlling the shielded barrel 17 of the vacuum reaction chamber 2, the coated aluminum foil 16, and the gas components that are introduced. Dry cleaning of SiC surfaces.
  • the angle between the central axes of the first and second ECR plasma sources 4 and 4a is 0 degree, the dry cleaning of the surface of the 6-inch SiC wafer can be completed, and the cleaning effect is remarkable.
  • the above-mentioned equipment is used for dry cleaning method of 4-inch SiC wafer.
  • the angle ⁇ between the central axes of the two ECR plasma sources is 45 degrees
  • the diameter of the quartz shielding barrel set around the sample stage 18 is 200 mm
  • the height is 60 mm.
  • An aluminum foil with a silicon oxide coating the thickness of the aluminum foil is 50 ⁇ m
  • the aluminum oxide on both sides of the aluminum foil is 20 nm
  • the thickness of the silicon oxide coating on the aluminum oxide surface is 1.5 ⁇ m.
  • the cleaning steps are the same as those in Example 1, except that in step 3, the included angle between the central axes of the first and second ECR plasma sources 4 and 4a is 45 degrees, and the cleaning time is 3 min.
  • the cleanliness of the SiC wafer surface after cleaning is basically the same as that in Example 1, and the reduction of the cleaning time shows that when the angle between the central axes of the two ECR plasma sources 4 and 4a is 45 degrees, due to the sample stage 18
  • the plasma covered in the middle area overlaps with each other to generate a higher density plasma, which improves the cleaning speed to a certain extent, indicating that the dry cleaning speed of a SiC semiconductor dry surface treatment equipment provided by the present invention is faster for smaller-sized samples , and the effect is not affected.
  • the two ECR plasma sources are placed vertically, that is, the angle ⁇ between the central axes of the two ECR plasma sources is 0 degrees; the diameter of the borosilicate glass shielding barrel set around the sample stage 18 is 220 mm , with a height of 60 mm, the metal inner wall surface of the vacuum reaction chamber 2 is covered with silicon nitride-coated aluminum foil, the thickness of the aluminum foil is 50 ⁇ m, the aluminum oxide on both sides of the aluminum foil is 20 nm, and the nitrogen on the aluminum oxide surface The silicon dioxide coating thickness is 1.5 ⁇ m.
  • the cleaning steps are as follows:
  • Steps 1 to 3 are the same as in Example 1, the difference is that the quartz shielding barrel in the vacuum reaction chamber 2 is replaced by a borosilicate glass shielding barrel of the same size, and the coating on both sides of the aluminum foil is replaced by silicon nitride film from silicon oxide film membrane.
  • Step 4 set the temperature of the sample stage 18 to be 400°C, pass the gas required for passivation treatment into the vacuum reaction chamber 2, the gas that is passed into is a gas combination of hydrogen, nitrogen and hydrogen chloride, and the flow ratio of the three gases is 8:1:1, wherein the gas flow rate of nitrogen is set to 6 sccm, the angle between the central axes of the first and second ECR plasma sources 4 and 4a is 0 degrees, the microwave power is set to 700 W, and in the vacuum reaction chamber 2 The air pressure was adjusted to 1 Pa, the passivation treatment time was 5 min, and the passivation treatment on the surface of the SiC wafer was started;
  • Step 5 After the surface treatment is completed, wait for the temperature to drop to room temperature, and take out the sample;
  • the gas flow monitoring and regulation in step 4 is realized through the gas distribution device as shown in FIG. 4 .
  • the gas components in the vacuum reaction chamber 2 are monitored by the residual gas analyzer 12, and the monitoring results are fed back to the computer information acquisition controller 23, and finally the MFC of each gas path is controlled in real time, so as to realize the monitoring of the gas composition in the vacuum reaction chamber 2. Precise control of components in situ.
  • Table 1 shows the gas components and proportions corresponding to the monitoring results under different cleaning times. It can be found that the gas components in the vacuum reaction chamber 2 are basically consistent during the cleaning time of 5 minutes, which proves that the equipped gas distribution system reliability and stability.
  • the surface lattice arrangement and roughness of the SiC wafer treated by the above method have been significantly improved, and there is no surface damage caused by excessive plasma cleaning on the surface, which shows that the in-situ gas control system equipped with a residual gas analyzer can realize the Precise control of the gas ratio in the vacuum reaction chamber.
  • the secondary ion mass spectrometry test found that the number and types of metal ions on the surface of the SiC wafer surface treated by the equipment of the present invention were significantly reduced compared with the samples cleaned by the previous equipment, which proves that the metal inner wall of the vacuum reaction chamber is covered with passivation.
  • the coated aluminum foil and the borosilicate glass shielding barrel set around the sample stage can effectively shield the bombardment of the plasma on the metal wall and reduce the contamination of the SiC surface by metal ions. Through calculation, the surface state density of the SiC wafer after treatment is significantly reduced, and the defect passivation effect is improved.
  • the method in this example is the same as that in Example 3, except that the coating on both sides of the aluminum foil is replaced by a combination of silicon nitride and boron nitride coating, the thickness of which is 2 ⁇ m.
  • the surface defect passivation effect and roughness of the SiC wafer after cleaning in Example 4 are the same as those in Example 3, and the density of states on the surface of the SiC wafer in Examples 3 and 4 are both distributed at 5 ⁇ 10 10 cm -2 eV -1 to 6 ⁇ 10 10 cm -2 eV -1 .
  • the surface roughness distribution of the AFM test is between 0.2 and 0.26 nm. Examples 3 and 4 have verified that the replacement of the shielding barrel and the aluminum foil coating has little effect on the surface treatment results, which illustrate the stability and rationality of the SiC semiconductor dry surface treatment equipment and method provided by the present invention.
  • the invention provides a dry method surface treatment equipment and method for SiC semiconductor, which adopts dual ECR plasma sources as the plasma generating device, and adjusts the plasma coverage area by changing the angle between the central axes of the two ECR sources, which can meet the requirement of 6 inches
  • the requirement for dry surface treatment of SiC wafers, the superimposition of dual ECR plasma source edge plasma improves the disadvantages of small uniform plasma area and low plasma density generated by a single plasma source;
  • the metal inner wall of the vacuum reaction chamber is covered with
  • the purpose of the aluminum foil with passivation coating and the shielding barrel of quartz or borosilicate glass around the sample stage is to shield the plasma from bombarding the metal wall, so as to reduce the pollution of metal particles to the SiC surface;
  • the traces of nitrogen and boron elements produced by the shielding barrel of aluminum foil with a passivation coating and quartz or borosilicate glass after plasma bombardment also have a beneficial effect on the passivation of SiC surface defects, and the aluminum foil pendant with a passivation
  • the equipment proposed in the present invention is also equipped with a residual gas analyzer.
  • a residual gas analyzer By monitoring the gas composition in the vacuum reaction chamber in real time, the gas flow rate and component distribution ratio during the passivation process can be precisely adjusted in situ to achieve the optimal cleaning effect. .

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Abstract

The present invention belongs to the field of semiconductor surface cleaning and passivation technology and relates to a SiC semiconductor dry surface treatment device and method. The treatment device comprises a dual ECR plasma supply apparatus, a vacuum reaction chamber, a sample loading chamber, a residual gas analyzer, a gas distribution apparatus, and a gas distribution system. The treatment method comprises the following steps: (1) vacuumizing the sample loading chamber; (2) vacuumizing the vacuum reaction chamber; (3) cleaning the surface of a SiC wafer; (4) passivating the surface of the SiC wafer; and (5) completing the surface treatment of the SiC wafer. According to the present invention, the dual ECR plasma source is used as a plasma generating apparatus, and the plasma coverage area is adjusted by changing the included angle between the intersection angles of the central axis of the two ECR plasma sources. The dry cleaning requirement of a 6-inch SiC wafer is satisfied, and the defects that the size of a plasma uniform region generated by a single ECR plasma source is small and the plasma density is low are improved.

Description

一种SiC半导体干法表面处理设备及方法A kind of SiC semiconductor dry method surface treatment equipment and method 技术领域technical field
本发明涉及一种SiC半导体干法表面处理设备及方法，属于半导体表面清洗及钝化技术领域。The invention relates to a SiC semiconductor dry surface treatment device and method, belonging to the technical field of semiconductor surface cleaning and passivation.
背景技术Background technique
SiC（碳化硅）是宽禁带半导体热点材料之一，其具备高的临界击穿电场、高热导率等优势，在耐高压高温功率器件领域具有重要的应用。此外，SiC还是外延生长石墨烯、氮化镓等材料的优选衬底。SiC (silicon carbide) is one of the wide-bandgap semiconductor hotspot materials. It has the advantages of high critical breakdown electric field and high thermal conductivity, and has important applications in the field of high-voltage and high-temperature power devices. In addition, SiC is also a preferred substrate for epitaxial growth of materials such as graphene and gallium nitride.
从半导体表面微结构和缺陷领域来看，SiC半导体通过传统湿法清洗后其表面依然存在碳残留、硅悬挂键、离子污染和表面污染等突出的新问题，一方面表面的缺陷很有可能以界面缺陷或固定电荷的形式存在于器件的界面，来俘获或发射电子，从而影响器件的阈值电压漂移和可靠性；另一方面，SiC表面的缺陷态会影响金属与半导体接触特性，从而影响SiC器件的效率及开关速度等性能。而且，SiC表面原子结构和形貌直接决定了外延生长的材料的晶体结构和薄膜质量。From the perspective of semiconductor surface microstructure and defects, SiC semiconductors still have outstanding new problems such as carbon residues, silicon dangling bonds, ion contamination, and surface contamination after conventional wet cleaning. On the one hand, surface defects are likely to be Interface defects or fixed charges exist at the interface of the device to capture or emit electrons, thereby affecting the threshold voltage drift and reliability of the device; on the other hand, the defect state on the SiC surface will affect the contact characteristics of the metal and semiconductor, thereby affecting the SiC Device efficiency and switching speed and other performance. Moreover, the atomic structure and morphology of the SiC surface directly determine the crystal structure and film quality of the epitaxially grown material.
对于目前已公开的技术方案，刘冰冰等人[申请号: 201510735852.X]提出采用ECR微波等离子体系统产生氢氮混合的等离子体对SiC表面进行清洗处理，可以显著降低表面态密度，并且有效抑制了氧化过程中界面缺陷态的生成，提高了氧化膜的击穿特性。For the currently disclosed technical solutions, people such as Liu Bingbing [Application No.: 201510735852.X] proposed to use the ECR microwave plasma system to generate hydrogen-nitrogen mixed plasma to clean the SiC surface, which can significantly reduce the surface state density, effectively inhibit the generation of interface defect states during the oxidation process, and improve the oxidation film. breakdown characteristics.
技术问题technical problem
尽管所述的已有设备和方法为SiC表面处理提供了技术支持，但是所述设备和方法还存在以下不足：单一等离子体源产生的等离子体覆盖面积有限，并且等离子体源边缘的密度较低，表面处理效果无法满足现阶段6英寸甚至更大尺寸的SiC晶片表面处理的需求；设备内壁金属容易受到等离子体的轰击，产生的金属离子会污染SiC晶片表面，这些金属离子在器件中以可动离子的形式存在，严重影响器件性能；表面处理过程中使用的气体无法实现精准调控，容易出现等离子体损伤SiC晶片表面的现象，影响SiC表面原子排布和结构。Although the existing equipment and methods described provide technical support for SiC surface treatment, the equipment and methods also have the following disadvantages: the plasma coverage area generated by a single plasma source is limited, and the density at the edge of the plasma source is low , the surface treatment effect cannot meet the surface treatment requirements of 6-inch or larger SiC wafers at this stage; the metal on the inner wall of the equipment is easily bombarded by plasma, and the metal ions generated will contaminate the SiC wafer surface. The presence of moving ions seriously affects device performance; the gas used in the surface treatment process cannot be precisely regulated, and it is easy to damage the surface of the SiC wafer by plasma, which affects the atomic arrangement and structure of the SiC surface.
技术解决方案technical solution
为了克服现有技术中存在的不足，本发明目的是提供一种SiC半导体干法表面处理设备及方法。该发明可以是单一的干法表面清洗，也可以是干法表面清洗后紧随着干法表面钝化处理，以适应于SiC器件的欧姆接触工艺和栅氧化层制备工艺的前期表面处理要求。本发明采用双ECR等离子体源作为等离子体发生装置，通过改变两个ECR源的中轴线夹角来调整等离子体覆盖面积，可以满足6英寸SiC晶片的干法表面处理需求，双ECR等离子体源边缘等离子体的相互叠加改善了单一等离子体源产生的等离子体均匀区尺寸小、等离子体密度较低的缺点；真空反应室金属内壁覆盖有带钝化涂层的铝箔挂件，以及样品台周围设置的石英或硼硅酸玻璃的屏蔽桶的目的都是为了屏蔽等离子体对金属器壁的轰击，以减少金属粒子对SiC表面的污染；带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶在等离子体轰击后产生的微量氮、硼元素也对钝化SiC表面缺陷起到有益的效果，且带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶具有更换方便、价格低廉等优点。此外，本发明所提出的设备还搭载了残余气体分析仪，通过对真空反应室中的气体成分进行实时监测，原位精准调控表面处理过程中的气体流量和组分配比，达到最优的表面处理效果。In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a SiC semiconductor dry surface treatment equipment and method. The invention can be single dry surface cleaning, or dry surface cleaning followed by dry surface passivation treatment, so as to adapt to the early surface treatment requirements of SiC device ohmic contact process and gate oxide layer preparation process. The present invention uses dual ECR plasma sources as the plasma generating device, and adjusts the plasma coverage area by changing the angle between the central axes of the two ECR sources, which can meet the dry surface treatment requirements of 6-inch SiC wafers. The dual ECR plasma sources The superimposition of edge plasmas improves the disadvantages of small plasma uniform area and low plasma density produced by a single plasma source; The purpose of the shielding barrel of quartz or borosilicate glass is to shield the bombardment of the plasma on the metal wall, so as to reduce the pollution of metal particles to the SiC surface; the aluminum foil pendant with passivation coating and quartz or borosilicate glass The trace nitrogen and boron elements produced by the shielding barrel after plasma bombardment also have a beneficial effect on the passivation of SiC surface defects, and the aluminum foil pendant with passivation coating and the shielding barrel of quartz or borosilicate glass are easy to replace , low price and other advantages. In addition, the equipment proposed in the present invention is also equipped with a residual gas analyzer. Through real-time monitoring of the gas composition in the vacuum reaction chamber, the gas flow rate and component distribution ratio during the surface treatment process can be precisely regulated in situ to achieve optimal surface treatment. processing effect.
为了实现上述发明目的，解决已有技术中所存在的问题，本发明采取的技术方案是：一种SiC半导体干法表面处理设备的处理方法，所述处理设备，包括双ECR等离子体供应装置、真空反应室、装样室、残余气体分析仪、配气装置及配气系统，所述真空反应室的上方设置有相同尺寸的第1、2ECR等离子体源、微波源及波导管，波导管设置有第1、2微波耦合天线共同构成双ECR等离子体供应装置；所述真空反应室顶部设置有法拉第筒、进气口、第1真空度计量器、电子探针及第1卤钨灯、所述真空反应室内部设置带有电加热装置的样品台，其中电子探针用来精准测控样品台的ECR等离子体的电子密度和温度，法拉第筒用来精准测控样品台的ECR等离子体的离子密度和温度；所述第1、2ECR等离子体源的接口法兰均固定在波纹管上，且第1、2ECR等离子体源的中轴线夹角可在0-45度之间调节，中轴线夹角为45度时的第1、2ECR等离子体源的轴心均正对着样品台中心，通过调节中轴线夹角来满足不同尺寸晶片的高质量清洗，另外，真空反应室底部通过管路与抽真空设备相连，真空反应室还设置有CCD成像系统、磁动机械手、观察窗及反射高能电子衍射仪，真空反应室的金属内壁表面布满带涂层的铝箔，样品台周围设置屏蔽桶，屏蔽桶的直径为180-240 mm，高为50-120 mm，屏蔽桶的材质选自石英或硼硅酸玻璃中的一种；带涂层铝箔的厚度为10-100 μm，铝箔的双侧表面均覆盖有5-20 nm的氧化铝薄膜，且氧化铝表面覆盖有涂层，涂层厚度为0.5-2 μm，涂层选自氧化硅膜、氮化硅膜、氮氧化硅膜、氮化硼膜中的一种或氧化硅膜、氮化硅膜、氮氧化硅膜、氮化硼膜的组合；样品台周围设置有石英或硼硅酸玻璃的屏蔽桶，用于屏蔽等离子体对金属器壁的轰击，以减少金属离子对SiC表面的污染，且带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶在等离子体轰击后产生的微量氮、硼元素也对钝化SiC表面缺陷起到有益的效果；所述装样室，放置在真空反应室的右侧，中间通过闸板阀与真空反应室相连接，装样室设置有第2卤钨灯，第2真空度计量器及放气阀；所述配气系统，包括设置在第1、2ECR等离子体源内部的第1、2石英杯，进气口分别与第1、2石英杯内的供气环管路相连，参与微波等离子体放电； 所述配气装置，包括设置在真空反应室一侧并与计算机信息采集控制器相连的残余气体分析仪，计算机信息采集控制器还分别与6路气体流量控制器相连，6路气源分别通过6个减压阀与6路气体流量控制器输入端相连，6路气体流量控制器输出端均与混气室输入端相连，混气室输出端通过真空截止阀与进气口相连；In order to achieve the purpose of the above invention and solve the problems existing in the prior art, the technical solution adopted by the present invention is: a treatment method for SiC semiconductor dry surface treatment equipment, the treatment equipment includes a double ECR plasma supply device, Vacuum reaction chamber, sample loading chamber, residual gas analyzer, gas distribution device and gas distribution system, the first and second ECR plasma sources, microwave sources and waveguides of the same size are arranged above the vacuum reaction chamber, and the waveguide is set The first and second microwave coupling antennas together constitute a dual ECR plasma supply device; the top of the vacuum reaction chamber is provided with a Faraday cup, an air inlet, a first vacuum gauge, an electronic probe and a first tungsten halogen lamp, and all A sample stage with an electric heating device is set inside the vacuum reaction chamber, wherein the electron probe is used to accurately measure and control the electron density and temperature of the ECR plasma of the sample stage, and the Faraday cylinder is used to accurately measure and control the ion density of the ECR plasma of the sample stage and temperature; the interface flanges of the first and second ECR plasma sources are all fixed on the bellows, and the central axis angle of the first and second ECR plasma sources can be adjusted between 0-45 degrees, and the central axis angle The axes of the first and second ECR plasma sources at 45 degrees are facing the center of the sample stage, and the high-quality cleaning of wafers of different sizes can be satisfied by adjusting the included angle of the central axis. Vacuum equipment is connected, and the vacuum reaction chamber is also equipped with a CCD imaging system, a magnetic manipulator, an observation window and a reflection high-energy electron diffractometer. The metal inner wall of the vacuum reaction chamber is covered with coated aluminum foil. The diameter of the barrel is 180-240 mm, the height is 50-120 mm, the material of the shielding barrel is selected from one of quartz or borosilicate glass; the thickness of coated aluminum foil is 10-100 μm, both sides of the aluminum foil are covered with 5-20 nm aluminum oxide film, and the aluminum oxide surface is covered with a coating, the coating thickness is 0.5-2 μm, and the coating is selected from one of silicon oxide film, silicon nitride film, silicon nitride oxide film, and boron nitride film Or a combination of silicon oxide film, silicon nitride film, silicon oxynitride film, and boron nitride film; a shielding barrel of quartz or borosilicate glass is arranged around the sample stage to shield the bombardment of the plasma on the metal wall, so as to Reduce the pollution of metal ions on the SiC surface, and the trace nitrogen and boron elements produced by the aluminum foil pendant with passivation coating and the shielding barrel of quartz or borosilicate glass after plasma bombardment are also beneficial to the passivation of SiC surface defects effect; the sample loading chamber is placed on the right side of the vacuum reaction chamber, and the middle is connected with the vacuum reaction chamber through a gate valve. The sample loading chamber is provided with the second halogen tungsten lamp, the second vacuum gauge and the deflation Valve; the gas distribution system includes the first and second quartz cups arranged inside the first and second ECR plasma sources, and the air inlets are respectively connected to the gas supply ring pipelines in the first and second quartz cups to participate in microwave plasma body discharge; the gas distribution device includes a residual gas analyzer arranged on one side of the vacuum reaction chamber and connected to a computer information acquisition controller, and the computer information acquisition controller is also connected to 6 gas flow controllers respectively, and the 6 gas flow controllers are respectively connected to each other. The sources are respectively connected to the input ends of the 6-way gas flow controllers through 6 pressure reducing valves, the output ends of the 6-way gas flow controllers are all connected to the input ends of the gas mixing chamber, and the output ends of the gas mixing chamber are connected to the air inlet through a vacuum stop valve ;
其中，所述处理方法，包括以下步骤：Wherein, the processing method comprises the following steps:
步骤1、对装样室进行抽真空，将样品放入装样室，开启抽真空设备对装样室抽真空至10 -4-10 -7 Pa，打开装样室与真空反应室之间的闸板阀，将样品送至真空反应室的样品台上，关闭闸板阀； Step 1. Vacuum the sample loading room, put the sample into the sample loading room, turn on the vacuum equipment to evacuate the sample loading room to 10 -4 -10 -7 Pa, open the gap between the sample loading room and the vacuum reaction chamber Gate valve, the sample is sent to the sample stage of the vacuum reaction chamber, and the gate valve is closed;
步骤2、对真空反应室进行抽真空，开启抽真空设备，对真空反应室进行抽真空，使真空度达到10 -5-10 -7 Pa； Step 2, vacuumize the vacuum reaction chamber, turn on the vacuum equipment, and vacuumize the vacuum reaction chamber to make the vacuum degree reach 10 -5 -10 -7 Pa;
步骤3、对SiC晶片表面进行清洗，设定样品台的温度为75-600 ℃，当温度达到表面处理温度时，启动配气系统，向真空反应室中通入清洗所需要的气体，通入的气体为氩气或氢气，气体流量设定为0-100 sccm，调节第1、2ECR等离子体源的中轴线夹角为0-45度，微波功率设定为300-2000 W，真空反应室2中的气压调节为0.5-2 Pa，清洗时间为1-20 min，开始对SiC晶片表面进行清洗，在表面处理过程中，配气系统中的残余气体分析仪对真空反应室内的各气体组分进行实时监测，监测结果反馈给计算机信息采集控制器，随后控制各气路的气体流量控制器来实现对真空反应室中的气体流量和配比的精准调控；Step 3. Clean the surface of the SiC wafer. Set the temperature of the sample stage to 75-600 °C. When the temperature reaches the surface treatment temperature, start the gas distribution system, and pass the gas required for cleaning into the vacuum reaction chamber. The gas used is argon or hydrogen, and the gas flow is set to 0-100 sccm, adjust the angle between the central axes of the first and second ECR plasma sources to be 0-45 degrees, set the microwave power to 300-2000 W, adjust the air pressure in the vacuum reaction chamber 2 to 0.5-2 Pa, and the cleaning time is 1- After 20 minutes, the SiC wafer surface was cleaned. During the surface treatment process, the residual gas analyzer in the gas distribution system monitored the gas components in the vacuum reaction chamber in real time, and the monitoring results were fed back to the computer information acquisition controller. Control the gas flow controllers of each gas path to achieve precise regulation of the gas flow and ratio in the vacuum reaction chamber;
步骤4、对SiC晶片表面进行钝化处理，设定样品台的温度为75-600 ℃，当温度达到表面处理温度时，向真空反应室中通入钝化处理所需要的气体，通入的气体为氢气，氮气，氯化氢，氯气，氨气中的一种或氢气，氮气，氯化氢，氯气，Step 4. Passivate the surface of the SiC wafer. Set the temperature of the sample stage to 75-600°C. When the temperature reaches the surface treatment temperature, pass the gas required for the passivation treatment into the vacuum reaction chamber. The gas is one of hydrogen, nitrogen, hydrogen chloride, chlorine, ammonia or hydrogen, nitrogen, hydrogen chloride, chlorine,
氨气的气体组合，各气路的气体流量设定为0-100 sccm，调节第1、2ECR等离子体源的中轴线夹角为0-45度，微波功率设定为300-2000 W，真空反应室中的气压调节为0.5-2 Pa，钝化处理时间为1-20 min，开始对SiC晶片表面进行钝化处理，在表面处理过程中，配气系统中的残余气体分析仪对真空反应室内的各气体组分进行实时监测，监测结果反馈给计算机信息采集控制器，随后控制各气路的气体流量控制器来实现对真空反应室中的气体流量和配比的精准调控；The gas combination of ammonia gas, the gas flow rate of each gas path is set to 0-100 sccm, the angle between the central axis of the first and second ECR plasma sources is adjusted to 0-45 degrees, the microwave power is set to 300-2000 W, and the vacuum The air pressure in the reaction chamber is adjusted to 0.5-2 Pa, the passivation treatment time is 1-20 min, and the passivation treatment is carried out on the surface of the SiC wafer. During the surface treatment process, the residual gas analyzer in the gas distribution system monitors the various gas components in the vacuum reaction chamber in real time. The monitoring results are fed back to the computer information acquisition controller, and then the gas flow controllers of each gas circuit are controlled to realize the precise regulation of the gas flow and proportion in the vacuum reaction chamber;
步骤5、SiC晶片表面处理完成，SiC晶片表面处理结束后，待温度降至室温，取出样品。Step 5. The surface treatment of the SiC wafer is completed. After the surface treatment of the SiC wafer is completed, the sample is taken out after the temperature drops to room temperature.
有益效果Beneficial effect
一种SiC半导体干法表面处理设备及方法，其中所述处理设备，包括双ECR等离子体供应装置、真空反应室、装样室、残余气体分析仪、配气装置及配气系统。所述处理方法，包括以下步骤：（1）对装样室进行抽真空，（2）对真空反应室进行抽真空，（3）对SiC晶片表面进行清洗，（4）对SiC晶片表面进行钝化处理，（5）SiC晶片表面处理完成。与已有技术相比，本发明采用双ECR等离子体源作为等离子体发生装置，通过改变两个ECR源的中轴线夹角来调整等离子体覆盖面积，可以满足6英寸SiC晶片的干法清洗需求，双ECR等离子体源边缘等离子体的相互叠加改善了单一等离子体源产生的等离子体均匀区尺寸小、等离子体密度较低的缺点；真空反应室金属内壁覆盖有带钝化涂层的铝箔挂件，以及样品台周围设置的石英或硼硅酸玻璃的屏蔽桶的目的都是为了屏蔽等离子体对金属器壁的轰击，以减少金属粒子对SiC表面的污染；带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶在等离子体轰击后产生的微量氮、硼元素也对钝化SiC表面缺陷起到有益的效果，且带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶具有更换方便、价格低廉等优点。此外，本发明所提出的设备还搭载了残余气体分析仪，通过对真空反应室中的气体成分进行实时监测，原位精准调控表面处理过程中的气体流量和组分配比，达到最优表面处理效果。A SiC semiconductor dry surface treatment equipment and method, wherein the treatment equipment includes a double ECR plasma supply device, a vacuum reaction chamber, a sample loading chamber, a residual gas analyzer, a gas distribution device and a gas distribution system. The processing method includes the following steps: (1) vacuumize the sample loading chamber, (2) vacuumize the vacuum reaction chamber, (3) clean the surface of the SiC wafer, (4) passivate the surface of the SiC wafer Chemical treatment, (5) SiC wafer surface treatment is completed. Compared with the prior art, the present invention uses dual ECR plasma sources as the plasma generating device, and adjusts the plasma coverage area by changing the angle between the central axes of the two ECR sources, which can meet the dry cleaning requirements of 6-inch SiC wafers , the superimposition of the edge plasma of the double ECR plasma source improves the disadvantages of the small size of the plasma uniform area and the low plasma density generated by the single plasma source; the metal inner wall of the vacuum reaction chamber is covered with an aluminum foil pendant with a passivation coating , and the purpose of the shielding barrel of quartz or borosilicate glass set around the sample stage is to shield the plasma from bombarding the metal wall, so as to reduce the pollution of metal particles to the SiC surface; the aluminum foil pendant with passivation coating and The trace nitrogen and boron elements produced by the shielding barrel of quartz or borosilicate glass after plasma bombardment also have a beneficial effect on the passivation of SiC surface defects, and the aluminum foil pendant with passivation coating and quartz or borosilicate glass The shielding barrel has the advantages of convenient replacement and low price. In addition, the equipment proposed in the present invention is also equipped with a residual gas analyzer. By monitoring the gas composition in the vacuum reaction chamber in real time, the gas flow rate and component distribution ratio during the surface treatment process can be precisely adjusted in situ to achieve optimal surface treatment. Effect.
附图说明Description of drawings
图1是本发明一种SiC半导体干法表面处理设备的俯视图。Fig. 1 is a top view of a SiC semiconductor dry surface treatment equipment according to the present invention.
图中：1、微波源，2、真空反应室，2a、法拉第筒，2b、进气口，2c、第1真空度计量器，2d、电子探针，2e、第1卤钨灯，3、波导管，3a、第1微波耦合天线，3b、第2微波耦合天线，4、第1ECR等离子体源，4a、第2ECR等离子体源，5、第1石英杯，5a、第2石英杯，6、装样室，6a、第2卤钨灯，6b、第2真空度计量器，6c、放气阀，7、闸板阀，8、CCD成像系统，9、抽真空设备，10、磁动机械手，11、观察窗，12、残余气体分析仪，13、反射高能电子衍射仪。In the figure: 1. Microwave source, 2. Vacuum reaction chamber, 2a, Faraday cup, 2b, air inlet, 2c, first vacuum gauge, 2d, electronic probe, 2e, first tungsten halogen lamp, 3, Waveguide, 3a, the first microwave coupling antenna, 3b, the second microwave coupling antenna, 4, the first ECR plasma source, 4a, the second ECR plasma source, 5, the first quartz cup, 5a, the second quartz cup, 6 , Sample chamber, 6a, the second tungsten halogen lamp, 6b, the second vacuum gauge, 6c, air release valve, 7, gate valve, 8, CCD imaging system, 9, vacuum equipment, 10, magnetic Manipulator, 11. Observation window, 12. Residual gas analyzer, 13. Reflection high energy electron diffractometer.
图2是本发明双ECR等离子体源垂直放置时图1的剖视图。Fig. 2 is a cross-sectional view of Fig. 1 when the double ECR plasma source of the present invention is placed vertically.
图中：14、波纹管，15、永磁铁环，16、带涂层的铝箔，17、屏蔽桶，18、样品台，19、加热装置，20、供气环管路。In the figure: 14, bellows, 15, permanent magnet ring, 16, coated aluminum foil, 17, shielding barrel, 18, sample stage, 19, heating device, 20, gas supply ring pipeline.
图3 是本发明双ECR等离子体源的中轴线夹角为45度放置时图1的剖视图。Fig. 3 is a cross-sectional view of Fig. 1 when the central axis of the dual ECR plasma source of the present invention is placed at an angle of 45 degrees.
图4 是本发明配气装置示意图。Fig. 4 is a schematic diagram of the gas distribution device of the present invention.
图中：21、混气室，22、真空截止阀，23、计算机信息采集控制器，24、减压阀，25、气体流量控制器（MFC）。In the figure: 21, gas mixing chamber, 22, vacuum stop valve, 23, computer information acquisition controller, 24, pressure reducing valve, 25, gas flow controller (MFC).
图5是本发明方法步骤流程图。Fig. 5 is a flowchart of the method steps of the present invention.
本发明的最佳实施方式BEST MODE FOR CARRYING OUT THE INVENTION
下面结合说明书附图及实施例对本发明作进一步说明。The present invention will be further described below in conjunction with the accompanying drawings and embodiments of the specification.
如图1、2、3、4所示，一种SiC半导体干法表面处理设备，包括双ECR等离子体供应装置、真空反应室2、装样室6、残余气体分析仪12、配气装置及配气系统，所述真空反应室2的上方设置有相同尺寸的第1、2ECR等离子体源4、4a、微波源1及波导管3，波导管3设置有第1、2微波耦合天线3a、3b共同构成双ECR等离子体供应装置；所述真空反应室2顶部设置有法拉第筒2a、进气口2b、第1真空度计量器2c、电子探针2d及第1卤钨灯2e、所述真空反应室2内部设置带有加热装置19的样品台18，其中电子探针2d用来精准测控样品台18的ECR等离子体的电子密度和温度，法拉第筒2a用来精准测控样品台18的ECR等离子体的离子密度和温度；所述第1、2ECR等离子体源4、4a的接口法兰均固定在波纹管14上，且第1、2ECR等离子体源的中轴线夹角可在0-45度之间调节，中轴线夹角为45度时的第1、2ECR等离子体源4、4a的轴心均正对着样品台18中心，通过调节中轴线夹角来满足不同尺寸晶片的高质量清洗，另外，真空反应室2底部通过管路与抽真空设备9相连，真空反应室2还设置有CCD成像系统8、磁动机械手10、观察窗11及反射高能电子衍射仪13，真空反应室2的金属内壁表面布满带涂层的铝箔16，样品台18周围设置屏蔽桶17，屏蔽桶17的直径为180-240 mm，高为50-120 mm，屏蔽桶17的材质选自石英或硼硅酸玻璃中的一种；带涂层铝箔16的厚度为10-100 μm，双侧表面均覆盖有5-20 nm的氧化铝薄膜，且氧化铝表面覆盖有涂层，涂层厚度为0.5-2 μm，涂层选自氧化硅膜、氮化硅膜、氮氧化硅膜、氮化硼膜中的一种或氧化硅膜、氮化硅膜、氮氧化硅膜、氮化硼膜的组合；样品台18周围设置有石英或硼硅酸玻璃的屏蔽桶17，用于屏蔽等离子体对金属器壁的轰击，以减少金属离子对SiC表面的污染，且带钝化涂层的铝箔和石英或硼硅酸玻璃的屏蔽桶17在等离子体轰击后产生的微量氮、硼元素也对钝化SiC表面缺陷起到有益的效果；所述装样室6，放置在真空反应室2的右侧，中间通过闸板阀7与真空反应室2相连接，装样室6设置有第2卤钨灯6a，第2真空度计量器6b及放气阀6c；所述配气系统，包括设置在第1、2ECR等离子体源4、4a内部的第1、2石英杯5、5a，进气口2b分别与第1、2石英杯5、5a内的供气环管路20相连，参与微波等离子体放电； 所述配气装置，包括设置在真空反应室2一侧并与计算机信息采集控制器23相连的残余气体分析仪12，计算机信息采集控制器23还分别与6路气体流量控制器25相连，6路气源分别通过6个减压阀24与6路气体流量控制器25输入端相连，6路气体流量控制器25输出端均与混气室21输入端相连，混气室21输出端通过真空截止阀22与进气口2b相连。As shown in Figures 1, 2, 3, and 4, a SiC semiconductor dry surface treatment equipment includes a double ECR plasma supply device, a vacuum reaction chamber 2, a sample loading chamber 6, a residual gas analyzer 12, a gas distribution device and Gas distribution system, the first and second ECR plasma sources 4, 4a, microwave source 1 and waveguide 3 of the same size are arranged above the vacuum reaction chamber 2, and the waveguide 3 is provided with the first and second microwave coupling antennas 3a, 3b together constitute a double ECR plasma supply device; the top of the vacuum reaction chamber 2 is provided with a Faraday cup 2a, an air inlet 2b, a first vacuum gauge 2c, an electronic probe 2d and a first tungsten halogen lamp 2e, the A sample stage 18 with a heating device 19 is arranged inside the vacuum reaction chamber 2, wherein the electron probe 2d is used to accurately measure and control the electron density and temperature of the ECR plasma of the sample stage 18, and the Faraday cage 2a is used to precisely measure and control the ECR of the sample stage 18. The ion density and temperature of the plasma; the interface flanges of the first and second ECR plasma sources 4 and 4a are all fixed on the bellows 14, and the angle between the central axes of the first and second ECR plasma sources can be 0-45 degrees, when the central axis angle is 45 degrees, the axes of the first and second ECR plasma sources 4 and 4a are all facing the center of the sample stage 18, and the high quality of wafers of different sizes can be satisfied by adjusting the central axis angle Cleaning, in addition, the bottom of the vacuum reaction chamber 2 is connected to the vacuum equipment 9 through pipelines, the vacuum reaction chamber 2 is also provided with a CCD imaging system 8, a magnetic manipulator 10, an observation window 11 and a reflection high-energy electron diffractometer 13, the vacuum reaction chamber The surface of the metal inner wall of 2 is covered with coated aluminum foil 16, and a shielding barrel 17 is arranged around the sample stage 18. The diameter of the shielding barrel 17 is 180-240 mm, and the height is 50-120 mm. mm, the material of the shielding barrel 17 is selected from one of quartz or borosilicate glass; the thickness of the coated aluminum foil 16 is 10-100 μm, and the surface of both sides is covered with a 5-20 nm aluminum oxide film, and the oxide The aluminum surface is covered with a coating with a coating thickness of 0.5-2 μm, the coating is selected from one of silicon oxide film, silicon nitride film, silicon nitride oxide film, boron nitride film or a combination of silicon oxide film, silicon nitride film, silicon nitride oxide film, boron nitride film; A shielding barrel 17 of quartz or borosilicate glass is arranged around the sample stage 18, which is used to shield the bombardment of the plasma on the metal wall, so as to reduce the pollution of metal ions to the SiC surface, and aluminum foil and quartz or The shielding barrel 17 of borosilicate glass produces trace amounts of nitrogen and boron elements after plasma bombardment and also has a beneficial effect on passivating SiC surface defects; the sample loading chamber 6 is placed on the right side of the vacuum reaction chamber 2, The middle is connected with the vacuum reaction chamber 2 through the gate valve 7, and the sample loading chamber 6 is provided with the second halogen lamp 6a, the second vacuum meter 6b and the air release valve 6c; the gas distribution system includes the second 1. The first and second quartz cups 5 and 5a inside the 2ECR plasma source 4 and 4a, and the gas inlet 2b are respectively connected to the gas supply ring pipeline 20 in the first and second quartz cups 5 and 5a to participate in the microwave plasma Discharge; The gas distribution device includes a residual gas analyzer 12 arranged on one side of the vacuum reaction chamber and connected to a computer information collection controller 23, and the computer information collection controller 23 is also connected to 6 gas flow controllers 25 respectively , the 6 gas sources are respectively connected to the input ends of the 6 gas flow controllers 25 through 6 pressure reducing valves 24, the output ends of the 6 gas flow controllers 25 are all connected to the input ends of the gas mixing chamber 21, and the output ends of the gas mixing chamber 21 It is connected to the air inlet 2b through a vacuum stop valve 22 .
本发明的实施方式Embodiments of the present invention
实施例Example 11
采用上述设备针对6英寸SiC晶片的干法清洗方法。The dry cleaning method for 6-inch SiC wafers was adopted with the above-mentioned equipment.
在本实施例中，两个ECR等离子体源均为垂直放置，即两个ECR等离子体源中轴线夹角θ为0度；样品台18周围设置的石英屏蔽桶17的直径为220 mm，高度为60 mm，真空反应室2的金属内壁表面布满带有氧化硅涂层的铝箔，铝箔厚度为50 μm，铝箔双侧表面的氧化铝均为20 nm，且氧化铝表面的氧化硅涂层厚度为1.5 μm。In this embodiment, the two ECR plasma sources are placed vertically, that is, the angle θ between the central axes of the two ECR plasma sources is 0 degrees; the diameter of the quartz shielding barrel 17 arranged around the sample stage 18 is 220 mm, and the height 60 mm, the metal inner wall surface of the vacuum reaction chamber 2 is covered with aluminum foil with silicon oxide coating, the thickness of the aluminum foil is 50 μm, the aluminum oxide on both sides of the aluminum foil is 20 nm, and the silicon oxide coating on the aluminum oxide surface The thickness is 1.5 μm.
清洗步骤如下：The cleaning steps are as follows:
步骤1、将6英寸SiC晶片放入装样室6，开启抽真空设备9对装样室6抽真空至10 -5 Pa，打开装样室6与真空反应室2之间的闸板阀7，再将6英寸SiC晶片送至真空反应室2的样品台18上，关闭闸板阀7； Step 1. Put a 6-inch SiC wafer into the sample loading chamber 6, turn on the vacuum equipment 9 to evacuate the sample loading chamber 6 to 10 -5 Pa, and open the gate valve 7 between the sample loading chamber 6 and the vacuum reaction chamber 2 , and then send the 6-inch SiC wafer to the sample stage 18 of the vacuum reaction chamber 2, and close the gate valve 7;
步骤2、开启抽真空设备9，对真空反应室2进行抽真空，使真空度达到10 -6 Pa； Step 2, turn on the vacuuming device 9, and vacuumize the vacuum reaction chamber 2 to make the vacuum degree reach 10 -6 Pa;
步骤3、设定样品台18的温度为400 ℃，当温度达到400 ℃时，启动配气系统，通入氢气，其中氢气的气流量为60 sccm，调节第1、2ECR等离子体源4与4a的中轴线夹角为0度，微波功率设置为700 W，真空反应室2中的气压调节为1 Pa，清洗时间为5 min；Step 3. Set the temperature of the sample stage 18 to 400°C. When the temperature reaches 400°C, start the gas distribution system and feed hydrogen gas, wherein the flow rate of hydrogen gas is 60 sccm, and adjust the first and second ECR plasma sources 4 and 4a The included angle of the central axis is 0 degrees, the microwave power is set to 700 W, the air pressure in the vacuum reaction chamber 2 is adjusted to 1 Pa, and the cleaning time is 5 min;
步骤4、清洗结束后，待温度降至室温，取出样品；Step 4. After cleaning, wait for the temperature to drop to room temperature and take out the sample;
通过上述实施例可以发现，本发明提供的一种半导体干法表面处理的设备是可以通过对真空反应室2的屏蔽桶17、带涂层的铝箔16、通入气体组分的调控来实现对SiC表面的干法清洗。当第1、2ECR等离子体源4与4a的中轴线夹角为0度时可以完成对6英寸SiC晶片表面的干法清洗，且清洗效果显著。It can be found through the foregoing embodiments that the device for dry surface treatment of a semiconductor provided by the present invention can be realized by controlling the shielded barrel 17 of the vacuum reaction chamber 2, the coated aluminum foil 16, and the gas components that are introduced. Dry cleaning of SiC surfaces. When the angle between the central axes of the first and second ECR plasma sources 4 and 4a is 0 degree, the dry cleaning of the surface of the 6-inch SiC wafer can be completed, and the cleaning effect is remarkable.
实施例Example 22
采用上述设备针对4英寸SiC晶片干法清洗方法。The above-mentioned equipment is used for dry cleaning method of 4-inch SiC wafer.
在本实施例中，两个ECR等离子体源中轴线夹角θ为45度，样品台18周围设置的石英屏蔽桶的直径为200 mm，高度为60 mm，真空反应室2的金属内壁表面布满带有氧化硅涂层的铝箔，铝箔厚度为50 μm，铝箔双侧表面的氧化铝均为20 nm，且氧化铝表面的氧化硅涂层厚度为1.5 μm。In this embodiment, the angle θ between the central axes of the two ECR plasma sources is 45 degrees, the diameter of the quartz shielding barrel set around the sample stage 18 is 200 mm, and the height is 60 mm. An aluminum foil with a silicon oxide coating, the thickness of the aluminum foil is 50 μm, the aluminum oxide on both sides of the aluminum foil is 20 nm, and the thickness of the silicon oxide coating on the aluminum oxide surface is 1.5 μm.
清洗步骤与实施例1相同，区别在于步骤3中的第1、2ECR等离子体源4与4a的中轴线夹角为45度，清洗时间为3 min。The cleaning steps are the same as those in Example 1, except that in step 3, the included angle between the central axes of the first and second ECR plasma sources 4 and 4a is 45 degrees, and the cleaning time is 3 min.
使用上述方法，清洗后的SiC晶片表面的洁净度与实施例1中的基本相同，清洗时间的减少说明两个ECR等离子体源4与4a的中轴线夹角为45度时，由于样品台18中间区域覆盖的等离子体相互重叠产生更高密度的等离子体一定程度上提升了清洗的速度，说明本发明提供的一种SiC半导体干法表面处理设备针对较小尺寸样品的干法清洗速度更快，且效果不受影响。Using the above method, the cleanliness of the SiC wafer surface after cleaning is basically the same as that in Example 1, and the reduction of the cleaning time shows that when the angle between the central axes of the two ECR plasma sources 4 and 4a is 45 degrees, due to the sample stage 18 The plasma covered in the middle area overlaps with each other to generate a higher density plasma, which improves the cleaning speed to a certain extent, indicating that the dry cleaning speed of a SiC semiconductor dry surface treatment equipment provided by the present invention is faster for smaller-sized samples , and the effect is not affected.
实施例Example 33
采用上述设备针对6英寸SiC晶片干法清洗后钝化的方法。The method of passivation after dry cleaning of 6-inch SiC wafers using the above-mentioned equipment.
在本实施例中，两个ECR等离子体源均为垂直放置，即两个ECR等离子体源中轴线夹角θ为0度；样品台18周围设置的硼硅酸玻璃屏蔽桶的直径为220 mm，高度为60 mm，真空反应室2的金属内壁表面布满带有氮化硅涂层的铝箔，铝箔厚度为50 μm，铝箔双侧表面的氧化铝均为20 nm，且氧化铝表面的氮化硅涂层厚度为1.5 μm。In this embodiment, the two ECR plasma sources are placed vertically, that is, the angle θ between the central axes of the two ECR plasma sources is 0 degrees; the diameter of the borosilicate glass shielding barrel set around the sample stage 18 is 220 mm , with a height of 60 mm, the metal inner wall surface of the vacuum reaction chamber 2 is covered with silicon nitride-coated aluminum foil, the thickness of the aluminum foil is 50 μm, the aluminum oxide on both sides of the aluminum foil is 20 nm, and the nitrogen on the aluminum oxide surface The silicon dioxide coating thickness is 1.5 μm.
清洗步骤如下：The cleaning steps are as follows:
步骤1至3与实施例1相同，区别在于真空反应室2中的石英屏蔽桶更换为相同尺寸的硼硅酸玻璃屏蔽桶，铝箔的双侧表面的涂层由氧化硅膜更换为氮化硅膜。Steps 1 to 3 are the same as in Example 1, the difference is that the quartz shielding barrel in the vacuum reaction chamber 2 is replaced by a borosilicate glass shielding barrel of the same size, and the coating on both sides of the aluminum foil is replaced by silicon nitride film from silicon oxide film membrane.
步骤4、设定样品台18的温度为400 ℃，向真空反应室2中通入钝化处理所需要的气体，通入的气体为氢气、氮气和氯化氢的气体组合，三种气体的流量比为8:1:1，其中氮气的气体流量设定为6 sccm，第1、2ECR等离子体源4与4a的中轴线夹角为0度，微波功率设定为700 W，真空反应室2中的气压调节为1 Pa，钝化处理时间为5 min，开始对SiC晶片表面进行钝化处理；Step 4, set the temperature of the sample stage 18 to be 400°C, pass the gas required for passivation treatment into the vacuum reaction chamber 2, the gas that is passed into is a gas combination of hydrogen, nitrogen and hydrogen chloride, and the flow ratio of the three gases is 8:1:1, wherein the gas flow rate of nitrogen is set to 6 sccm, the angle between the central axes of the first and second ECR plasma sources 4 and 4a is 0 degrees, the microwave power is set to 700 W, and in the vacuum reaction chamber 2 The air pressure was adjusted to 1 Pa, the passivation treatment time was 5 min, and the passivation treatment on the surface of the SiC wafer was started;
步骤5、表面处理结束后，待温度降至室温，取出样品；Step 5. After the surface treatment is completed, wait for the temperature to drop to room temperature, and take out the sample;
其中，在步骤4中的气体流量监测和调控是通过如图4所示的配气装置实现的。真空反应室2内的气体组分通过残余气体分析仪12来监测，监测结果反馈至计算机信息采集控制器23，最后实时对各气路的MFC进行控制，从而实现对真空反应室2内的气体组分的原位精准调控。表1中展示了不同清洗时间下监测结果所对应的气体组分及占比，可以发现在5 min的清洗时间内真空反应室2中的气体组分基本保持一致，证明所搭载的配气系统的可靠性和稳定性。Wherein, the gas flow monitoring and regulation in step 4 is realized through the gas distribution device as shown in FIG. 4 . The gas components in the vacuum reaction chamber 2 are monitored by the residual gas analyzer 12, and the monitoring results are fed back to the computer information acquisition controller 23, and finally the MFC of each gas path is controlled in real time, so as to realize the monitoring of the gas composition in the vacuum reaction chamber 2. Precise control of components in situ. Table 1 shows the gas components and proportions corresponding to the monitoring results under different cleaning times. It can be found that the gas components in the vacuum reaction chamber 2 are basically consistent during the cleaning time of 5 minutes, which proves that the equipped gas distribution system reliability and stability.
表1Table 1
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 the
使用上述方法处理后的SiC晶片表面晶格排布和粗糙度有了明显提升，表面没有出现等离子体过度清洗引起的表面损伤现象，这说明搭载残余气体分析仪的原位气体调控系统可以实现对真空反应室中气体配比的精准调控。二次离子质谱测试发现采用本发明的设备所处理后的SiC晶片表面相比于采用之前的设备清洗的样品，表面金属离子数量及种类明显降低，这证明真空反应室金属内壁覆盖有带钝化涂层的铝箔和样品台周围设置的硼硅酸玻璃的屏蔽桶可以有效屏蔽等离子体对金属器壁的轰击，减少金属离子对SiC表面的污染。通过计算，处理后SiC晶片的表面态密度显著降低，缺陷钝化效果有所提升。The surface lattice arrangement and roughness of the SiC wafer treated by the above method have been significantly improved, and there is no surface damage caused by excessive plasma cleaning on the surface, which shows that the in-situ gas control system equipped with a residual gas analyzer can realize the Precise control of the gas ratio in the vacuum reaction chamber. The secondary ion mass spectrometry test found that the number and types of metal ions on the surface of the SiC wafer surface treated by the equipment of the present invention were significantly reduced compared with the samples cleaned by the previous equipment, which proves that the metal inner wall of the vacuum reaction chamber is covered with passivation. The coated aluminum foil and the borosilicate glass shielding barrel set around the sample stage can effectively shield the bombardment of the plasma on the metal wall and reduce the contamination of the SiC surface by metal ions. Through calculation, the surface state density of the SiC wafer after treatment is significantly reduced, and the defect passivation effect is improved.
实施例Example 44
本实施例中的方法与实施例3中的相同，区别在于铝箔双侧表面涂层更换为氮化硅和氮化硼涂层组合，其厚度为2 μm。The method in this example is the same as that in Example 3, except that the coating on both sides of the aluminum foil is replaced by a combination of silicon nitride and boron nitride coating, the thickness of which is 2 μm.
采用实施例4清洗后的SiC晶片表面缺陷钝化效果和粗糙度与实施例3中的结果相同，通过计算实施例3和4中的SiC晶片表面态密度均分布在5×10 10 cm -2eV -1到6×10 10 cm -2eV -1。AFM测试的表面粗糙度分布在0.2~0.26 nm之间。实施例3和4验证了更换屏蔽桶和铝箔涂层对表面处理结果影响不大，说明本发明所提供的一种SiC半导体干法表面处理设备及方法的稳定性与合理性。 The surface defect passivation effect and roughness of the SiC wafer after cleaning in Example 4 are the same as those in Example 3, and the density of states on the surface of the SiC wafer in Examples 3 and 4 are both distributed at 5×10 10 cm -2 eV -1 to 6×10 10 cm -2 eV -1 . The surface roughness distribution of the AFM test is between 0.2 and 0.26 nm. Examples 3 and 4 have verified that the replacement of the shielding barrel and the aluminum foil coating has little effect on the surface treatment results, which illustrate the stability and rationality of the SiC semiconductor dry surface treatment equipment and method provided by the present invention.
工业实用性Industrial Applicability
本发明提供了一种SiC半导体干法表面处理设备及方法，采用双ECR等离子体源作为等离子体发生装置，通过改变两个ECR源的中轴线夹角来调整等离子体覆盖面积，可以满足6英寸SiC晶片的干法表面处理需求，双ECR等离子体源边缘等离子体的相互叠加改善了单一等离子体源产生的等离子体均匀区尺寸小、等离子体密度较低的缺点；真空反应室金属内壁覆盖有带钝化涂层的铝箔，以及样品台周围设置的石英或硼硅酸玻璃的屏蔽桶的目的都是为了屏蔽等离子体对金属器壁的轰击，以减少金属粒子对SiC表面的污染；带钝化涂层的铝箔和石英或硼硅酸玻璃的屏蔽桶在等离子体轰击后产生的微量氮、硼元素也对钝化SiC表面缺陷起到有益的效果，且带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶具有更换方便、价格低廉等优点。此外，本发明所提出的设备还搭载了残余气体分析仪，通过对真空反应室中的气体成分进行实时监测，原位精准调控钝化过程中的气体流量和组分配比，达到最优清洗效果。The invention provides a dry method surface treatment equipment and method for SiC semiconductor, which adopts dual ECR plasma sources as the plasma generating device, and adjusts the plasma coverage area by changing the angle between the central axes of the two ECR sources, which can meet the requirement of 6 inches The requirement for dry surface treatment of SiC wafers, the superimposition of dual ECR plasma source edge plasma improves the disadvantages of small uniform plasma area and low plasma density generated by a single plasma source; the metal inner wall of the vacuum reaction chamber is covered with The purpose of the aluminum foil with passivation coating and the shielding barrel of quartz or borosilicate glass around the sample stage is to shield the plasma from bombarding the metal wall, so as to reduce the pollution of metal particles to the SiC surface; The traces of nitrogen and boron elements produced by the shielding barrel of aluminum foil with a passivation coating and quartz or borosilicate glass after plasma bombardment also have a beneficial effect on the passivation of SiC surface defects, and the aluminum foil pendant with a passivation coating and The shielding barrel of quartz or borosilicate glass has the advantages of easy replacement and low price. In addition, the equipment proposed in the present invention is also equipped with a residual gas analyzer. By monitoring the gas composition in the vacuum reaction chamber in real time, the gas flow rate and component distribution ratio during the passivation process can be precisely adjusted in situ to achieve the optimal cleaning effect. .
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Claims (1)

  1. 一种SiC半导体干法表面处理设备的处理方法，其特征在于：所述处理设备包括双ECR等离子体供应装置、真空反应室、装样室、残余气体分析仪、配气装置及配气系统；A treatment method for SiC semiconductor dry surface treatment equipment, characterized in that: the treatment equipment includes a double ECR plasma supply device, a vacuum reaction chamber, a sample loading chamber, a residual gas analyzer, a gas distribution device and a gas distribution system;
    所述真空反应室的上方设置有相同尺寸的第1、2ECR等离子体源、微波源及波导管，波导管设置有第1、2微波耦合天线共同构成双ECR等离子体供应装置；所述真空反应室顶部设置有法拉第筒、进气口、第1真空度计量器、电子探针及第1卤钨灯、所述真空反应室内部设置带有电加热装置的样品台，其中电子探针用来精准测控样品台的ECR等离子体的电子密度和温度，法拉第筒用来精准测控样品台的ECR等离子体的离子密度和温度；The first and second ECR plasma sources, microwave sources and wave guides of the same size are arranged above the vacuum reaction chamber, and the wave guides are provided with the first and second microwave coupling antennas to form a dual ECR plasma supply device; the vacuum reaction The top of the chamber is provided with a Faraday cup, an air inlet, a first vacuum degree gauge, an electronic probe and a first halogen tungsten lamp, and a sample stage with an electric heating device is arranged inside the vacuum reaction chamber, wherein the electronic probe is used for Precisely measure and control the electron density and temperature of the ECR plasma on the sample stage, and the Faraday cup is used to accurately measure and control the ion density and temperature of the ECR plasma on the sample stage;
    所述第1、2ECR等离子体源的接口法兰均固定在波纹管上，且第1、2ECR等离子体源的中轴线夹角可在0-45度之间调节，中轴线夹角为45度时的第1、2ECR等离子体源的轴心均正对着样品台中心，通过调节中轴线夹角来满足不同尺寸晶片的高质量清洗，另外，真空反应室底部通过管路与抽真空设备相连，真空反应室还设置有CCD成像系统、磁动机械手、观察窗及反射高能电子衍射仪，真空反应室的金属内壁表面布满带涂层的铝箔，样品台周围设置屏蔽桶，屏蔽桶的直径为180-240 mm，高为50-120 mm，屏蔽桶的材质选自石英或硼硅酸玻璃中的一种，带涂层铝箔的厚度为10-100μm，铝箔的双侧表面均覆盖有5-20 nm的氧化铝薄膜，且氧化铝表面覆盖有涂层，涂层厚度为0.5-2 μm，涂层选自氧化硅膜、氮化硅膜、氮氧化硅膜、氮化硼膜中的一种或氧化硅膜、氮化硅膜、氮氧化硅膜、氮化硼膜的组合；样品台周围设置有石英或硼硅酸玻璃的屏蔽桶，用于屏蔽等离子体对金属器壁的轰击，以减少金属离子对SiC表面的污染，且带钝化涂层的铝箔挂件和石英或硼硅酸玻璃的屏蔽桶在等离子体轰击后产生的微量氮、硼元素也对钝化SiC表面缺陷起到有益的效果；The interface flanges of the first and second ECR plasma sources are all fixed on the bellows, and the included angle of the central axis of the first and second ECR plasma sources can be adjusted between 0-45 degrees, and the included angle of the central axis is 45 degrees The axes of the 1st and 2nd ECR plasma sources are facing the center of the sample stage, and the angle between the central axes can be adjusted to meet the high-quality cleaning of wafers of different sizes. In addition, the bottom of the vacuum reaction chamber is connected to the vacuum equipment through pipelines , the vacuum reaction chamber is also equipped with a CCD imaging system, a magnetic manipulator, an observation window and a reflection high-energy electron diffractometer. The metal inner wall of the vacuum reaction chamber is covered with coated aluminum foil, and a shielding barrel is set around the sample stage. The diameter of the shielding barrel is 180-240 mm in height and 50-120 mm in height. The material of the shielding barrel is selected from one of quartz or borosilicate glass. The thickness of the coated aluminum foil is 10-100 μm. Both sides of the aluminum foil are covered with 5 -20 nm aluminum oxide film, and the aluminum oxide surface is covered with a coating, the coating thickness is 0.5-2 μm, and the coating is selected from silicon oxide film, silicon nitride film, silicon nitride oxide film, boron nitride film One or a combination of silicon oxide film, silicon nitride film, silicon oxynitride film, boron nitride film; a shielding barrel of quartz or borosilicate glass is set around the sample stage to shield the bombardment of the plasma on the metal wall , in order to reduce the pollution of metal ions to the SiC surface, and the aluminum foil pendant with passivation coating and the shielding bucket of quartz or borosilicate glass are also produced by the trace nitrogen and boron elements after plasma bombardment to passivate SiC surface defects. to beneficial effect;
    所述装样室放置在真空反应室的右侧，中间通过闸板阀与真空反应室相连接，装样室设置有第2卤钨灯，第2真空度计量器及放气阀；所述配气系统，包括设置在第1、2ECR等离子体源内部的第1、2石英杯，进气口分别与第1、2石英杯内的供气环管路相连，参与微波等离子体放电； The sample loading chamber is placed on the right side of the vacuum reaction chamber, and the middle is connected with the vacuum reaction chamber through a gate valve. The sample loading chamber is provided with a 2nd halogen tungsten lamp, a 2nd vacuum gauge and an air release valve; The gas distribution system includes the first and second quartz cups arranged inside the first and second ECR plasma sources, and the gas inlets are respectively connected to the gas supply ring pipelines in the first and second quartz cups to participate in microwave plasma discharge;
    所述配气装置包括设置在真空反应室一侧并与计算机信息采集控制器相连的残余气体分析仪，计算机信息采集控制器还分别与6路气体流量控制器相连，6路气源分别通过6个减压阀与6路气体流量控制器输入端相连，6路气体流量控制器输出端均与混气室输入端相连，混气室输出端通过真空截止阀与进气口相连；The gas distribution device includes a residual gas analyzer arranged on one side of the vacuum reaction chamber and connected to a computer information collection controller. The computer information collection controller is also connected to 6 gas flow controllers respectively, and the 6 gas sources are respectively passed through 6 A pressure reducing valve is connected to the input end of the 6-way gas flow controller, the output ends of the 6-way gas flow controller are connected to the input end of the gas mixing chamber, and the output end of the gas mixing chamber is connected to the air inlet through a vacuum stop valve;
    其中，所述处理方法，包括以下步骤：Wherein, the processing method comprises the following steps:
    步骤1、对装样室进行抽真空，将样品放入装样室，开启抽真空设备对装样室抽真空至10 -4-10 -7 Pa，打开装样室与真空反应室之间的闸板阀，将样品送至真空反应室的样品台上，关闭闸板阀； Step 1. Vacuum the sample loading room, put the sample into the sample loading room, turn on the vacuum equipment to evacuate the sample loading room to 10 -4 -10 -7 Pa, open the gap between the sample loading room and the vacuum reaction chamber Gate valve, the sample is sent to the sample stage of the vacuum reaction chamber, and the gate valve is closed;
    步骤2、对真空反应室进行抽真空，开启抽真空设备，对真空反应室进行抽真空，使真空度达到10 -5-10 -7 Pa； Step 2, vacuumize the vacuum reaction chamber, turn on the vacuum equipment, and vacuumize the vacuum reaction chamber to make the vacuum degree reach 10 -5 -10 -7 Pa;
    步骤3、对SiC晶片表面进行清洗，设定样品台的温度为75-600 ℃，当温度达到表面处理温度时，启动配气系统，向真空反应室中通入清洗所需要的气体，通入的气体为氩气或氢气，气体流量设定为0-100sccm，调节第1、2ECR等离子体源的中轴线夹角为0-45度，微波功率设定为300-2000 W，真空反应室2中的气压调节为0.5-2 Pa，清洗时间为1-20 min，开始对SiC晶片表面进行清洗，在表面处理过程中，配气系统中的残余气体分析仪对真空反应室内的各气体组分进行实时监测，监测结果反馈给计算机信息采集控制器，随后控制各气路的气体流量控制器来实现对真空反应室中的气体流量和配比的精准调控；Step 3. Clean the surface of the SiC wafer. Set the temperature of the sample stage to 75-600 °C. When the temperature reaches the surface treatment temperature, start the gas distribution system, and pass the gas required for cleaning into the vacuum reaction chamber. The gas used is argon or hydrogen, the gas flow rate is set to 0-100 sccm, the angle between the central axis of the first and second ECR plasma sources is adjusted to 0-45 degrees, the microwave power is set to 300-2000 W, and the vacuum reaction chamber 2 The air pressure in the vacuum chamber is adjusted to 0.5-2 Pa, and the cleaning time is 1-20 min. The surface of the SiC wafer is cleaned. Real-time monitoring is carried out, and the monitoring results are fed back to the computer information acquisition controller, and then the gas flow controllers of each gas path are controlled to realize the precise regulation of the gas flow and proportion in the vacuum reaction chamber;
    步骤4、对SiC晶片表面进行钝化处理，设定样品台的温度为75-600 ℃，当温度达到表面处理温度时，向真空反应室中通入钝化处理所需要的气体，通入的气体为氢气，氮气，氯化氢，氯气，氨气中的一种或氢气，氮气，氯化氢，氯气，氨气的气体组合，各气路的气体流量设定为0-100sccm，调节第1、2ECR等离子体源的中轴线夹角为0-45度，微波功率设定为300-2000 W，真空反应室中的气压调节为0.5-2 Pa，钝化处理时间为1-20 min，开始对SiC晶片表面进行钝化处理，在表面处理过程中，配气系统中的残余气体分析仪对真空反应室内的各气体组分进行实时监测，监测结果反馈给计算机信息采集控制器，随后控制各气路的气体流量控制器来实现对真空反应室中的气体流量和配比的精准调控；Step 4. Passivate the surface of the SiC wafer. Set the temperature of the sample stage to 75-600°C. When the temperature reaches the surface treatment temperature, pass the gas required for the passivation treatment into the vacuum reaction chamber. The gas is one of hydrogen, nitrogen, hydrogen chloride, chlorine, ammonia, or a combination of hydrogen, nitrogen, hydrogen chloride, chlorine, and ammonia. The gas flow of each gas path is set to 0-100 sccm, and the first and second ECR plasmas are adjusted. The included angle of the central axis of the body source is 0-45 degrees, the microwave power is set to 300-2000 W, the air pressure in the vacuum reaction chamber is adjusted to 0.5-2 Pa, the passivation treatment time is 1-20 min, and the SiC wafer is started The surface is passivated. During the surface treatment, the residual gas analyzer in the gas distribution system monitors the gas components in the vacuum reaction chamber in real time. The monitoring results are fed back to the computer information acquisition controller, and then control the flow of each gas path The gas flow controller is used to realize the precise control of the gas flow and proportion in the vacuum reaction chamber;
    步骤5、SiC晶片表面处理完成，SiC晶片表面处理结束后，待温度降至室温，取出样品。Step 5. The surface treatment of the SiC wafer is completed. After the surface treatment of the SiC wafer is completed, the sample is taken out after the temperature drops to room temperature.
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