Microwave-radio frequency mixing coupled plasma discharging and modulating system and method

Abstract

The invention discloses a microwave-radio frequency mixing coupled plasma discharge and modulation system and method, and relates to the technical field of ion beam processing, and a gas distributor conveys process gas to an ECR region and a radio frequency enhanced discharge chamber; adjusting the power of the microwave antenna to enable the process gas in the ECR region to form initial plasma; adjusting the voltage of the electron leading-out grid electrode, and leading out electrons in the initial plasma into the radio frequency enhanced discharge chamber; the radio-frequency power supply loads radio-frequency voltage to the radio-frequency coil, so that electrons collide with process gas in the radio-frequency enhanced discharge chamber to form high-density plasma; adjusting the ion extraction grid to enable the ions in the high-density plasma to form an ion beam current; if the density of the ion beam meets the stability requirement, determining the ion beam output by the ion extraction grid as a target ion beam for etching; otherwise, each power supply is adjusted until the target ion beam current is obtained. According to the invention, long-time efficient and stable etching of the ion source is realized.

Description

Technical Field

[0001] The present application relates to the technical field of ion beam processing, and in particular to a microwave-radio frequency mixing coupled plasma discharge and modulation system and method. Background Art

[0002] Since the 1960s, the manufacturing of ultra-smooth optical surfaces, large-scale integrated circuits, super-surfaces and micro-nano structures has made great progress, requiring high-efficiency, high-stability and flexible and controllable ion etching processes. In recent years, plasma etching and ion beam etching technologies have been widely used in ion etching processes, and based on this, reactive ion etching (RIE) technology and reactive ion beam etching (RIBE) technology with reactive gases as process gases have been developed; at the same time, chemically assisted ion etching (CAIBE) technology has also made great progress in the industry.

[0003] These technologies all require high-performance, high plasma density and a certain beam density ion generator as the basis to obtain high-performance plasma, so as to obtain high etching selectivity, high etching rate and uniformity.

[0004] In existing ion generators, the plasma generation and modulation methods mainly include DC cathode heating discharge (represented by Kaufman cathode ion source), radio frequency discharge (including inductively coupled discharge and capacitively coupled discharge, represented by the RIT series developed by the University of Giessen and the radio frequency ion source of Veeco in the United States) and electron cyclotron resonance discharge (ECR).

[0005] However, the filament life of the Kaufman cathode ion source (mainly made of LaB6 and barium tungsten) is limited. In corrosive gas conditions, the cathode life is greatly reduced, and metal ion pollution is also caused. The RF ion source avoids the disadvantages of service life and pollution, but its defect is that the electron density in the discharge chamber plays a decisive role in the RF discharge and gas ionization rate. When electronegative gases such as SF6 and O2 are introduced, the electron density in the discharge chamber is greatly reduced, causing the plasma to oscillate or even disappear.

[0006] As for the microwave ion source, its disadvantage is that the heat is high. Microwave radiation and ion collision cause the grid to heat up seriously. In the etching process, especially when the substrate mask is a heat-sensitive photoresist, corresponding water cooling measures must be taken. At the same time, the microwave discharge mechanism is still under exploration, and it is difficult to achieve plasma modulation.

[0007] Therefore, how to realize the generation and modulation of plasma in a plasma generator to meet the growing demand for surface etching has become a key technical issue that needs to be solved urgently. Summary of the invention

[0008] The purpose of the present application is to provide a microwave-RF mixing coupled plasma discharge and modulation system and method to overcome the problems of poor adaptability of RF ion sources to electronegative gases, low ionization rate and plasma density, and difficulty in stable control.

[0009] To achieve the above objectives, this application provides the following solutions:

[0010] In a first aspect, the present application provides a microwave-radio frequency mixing coupled plasma discharge and modulation system, comprising: a gas distribution system, multiple power supplies, an ion beam generating device, a Faraday cup and a computer; the multiple power supplies are: an accelerating grid DC regulated power supply, a screen grid DC regulated power supply, a radio frequency power supply, an electron extraction pole DC regulated power supply and a solid-state microwave power supply; the ion beam generating device comprises: a metal shielding shell with an open top and a first metal microwave shielding shell, a microwave antenna, a microwave static magnetic field, a microwave discharge chamber, an electron extraction grid, a gas distributor, a second metal microwave shielding shell, a radio frequency coil, a radio frequency enhanced discharge chamber and an ion extraction grid arranged inside the metal shielding shell; the second metal microwave shielding shell, the microwave antenna, the microwave static magnetic field, the microwave discharge chamber and the electron extraction grid together form an ECR area; a Faraday cup is arranged in the emission direction of the ion beam of the ion extraction grid; the radio frequency coil surrounds the periphery of the radio frequency enhanced discharge chamber;

[0011] The gas distribution system, the accelerating grid DC regulated power supply, the screen grid DC regulated power supply, the radio frequency power supply, the electron extraction pole DC regulated power supply, the solid-state microwave power supply and the Faraday cup are all connected to the computer; the gas distribution system is in communication with the gas distributor; the solid-state microwave power supply is connected to the microwave antenna, the electron extraction pole DC regulated power supply is connected to the electron extraction grid, the radio frequency power supply is connected to the radio frequency coil, and the accelerating grid DC regulated power supply and the screen grid DC regulated power supply are both connected to the ion extraction grid;

[0012] The computer is used to obtain etching requirements and determine the ratio of process gases based on the etching requirements;

[0013] The gas distribution system is used to store process gas and deliver process gas to the gas distributor according to the ratio;

[0014] The gas distributor is used to deliver a portion of the process gas to the ECR zone and another portion of the process gas to the RF enhanced discharge chamber;

[0015] The solid-state microwave power supply is used to adjust its own power under the control of the computer, thereby adjusting the power of the microwave antenna, so that the process gas in the ECR zone discharges to form an initial plasma;

[0016] The electron extraction electrode DC regulated power supply is used to adjust its own voltage under the control of the computer, thereby adjusting the voltage of the electron extraction grid, and extracting the electrons in the initial plasma into the radio frequency enhanced discharge chamber;

[0017] The RF power supply is used to adjust its own power to generate RF voltage under the control of the computer, and load the RF voltage to the RF coil, so that the electrons further collide with the process gas in the RF enhanced discharge chamber to form high-density plasma; the high-density plasma is a plasma with a density higher than that of the initial plasma;

[0018] The screen grid DC regulated power supply and the accelerating grid DC regulated power supply are used to adjust the voltage of the ion extraction grid to a voltage that meets the voltage requirement under the control of the computer, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam;

[0019] The Faraday cup is used to measure the density of the ion beam;

[0020] The computer is also used to:

[0021] Determine whether the density of the ion beam meets the stability requirement; the stability requirement is that the density of the ion beam output by the ion extraction grid meets the density requirement within a set time;

[0022] If yes, the ion beam current output by the ion extraction grid is determined as the target ion beam current for etching;

[0023] If not, each power supply is controlled to adjust the voltage or power until the density of the ion beam meets the stability requirement, thereby obtaining the target ion beam.

[0024] In one embodiment, the gas distribution system comprises: a plurality of compressed gas cylinders, a plurality of gas mass flow meters and a gas mixing tank; one of the compressed gas cylinders is connected to one of the gas mass flow meters, each of the compressed gas cylinders is connected to the gas mixing tank, and the gas mixing tank is connected to the gas distributor; each of the gas mass flow meters is connected to the computer;

[0025] The computer is also used to:

[0026] Obtaining the gas mass flow rate of the corresponding compressed gas cylinder collected by each of the gas mass flow meters;

[0027] Controlling each of the compressed gas cylinders to deliver gas to the gas mixing tank based on the gas mass flow rate of each compressed gas cylinder and the ratio;

[0028] The gas mixing tank is used to mix the gases delivered by the compressed gas cylinders to obtain process gas, and deliver the process gas to the gas distributor.

[0029] In one embodiment, circular holes are evenly distributed on the gas distributor, and the gas distributor simultaneously delivers process gas to the ECR area and the RF enhanced discharge chamber through the circular holes.

[0030] In one embodiment, the first metal microwave shielding shell and the second metal microwave shielding shell are made of stainless steel or aluminum alloy.

[0031] In one embodiment, the microwave static magnetic field is composed of an annular multi-pole high temperature resistant fir cobalt magnet, and the magnetic field intensity of the microwave static magnetic field is greater than 875GS.

[0032] In one embodiment, the microwave discharge chamber is made of quartz or ceramic material.

[0033] In one embodiment, the electron extraction grid is composed of graphite or molybdenum grid.

[0034] In one embodiment, the ion extraction grid includes: a screen grid, an acceleration grid and a deceleration grid arranged from bottom to top;

[0035] The acceleration grid DC regulated power supply is connected to the acceleration grid; the screen grid DC regulated power supply is connected to the screen grid.

[0036] In one embodiment, the ion extraction grid is made of a conductive material; the conductive material includes molybdenum, stainless steel and graphite.

[0037] In a second aspect, the present application provides a microwave-RF mixing coupled plasma discharge and modulation method, which is implemented based on the microwave-RF mixing coupled plasma discharge and modulation system described in any one of the above items, and the microwave-RF mixing coupled plasma discharge and modulation method includes:

[0038] The computer obtains the etching requirement and determines the ratio of the process gas based on the etching requirement;

[0039] The gas distribution system delivers process gas to the gas distributor according to the ratio;

[0040] The gas distributor delivers a portion of the process gas to the ECR zone and another portion of the process gas to the RF enhanced discharge chamber;

[0041] The solid-state microwave power supply adjusts its own power under the control of the computer, thereby adjusting the power of the microwave antenna, so that the process gas in the ECR zone discharges to form an initial plasma;

[0042] The electron extraction electrode DC regulated power supply adjusts its own voltage under the control of the computer, thereby adjusting the voltage of the electron extraction grid, and extracting the electrons in the initial plasma into the radio frequency enhanced discharge chamber;

[0043] The RF power supply adjusts its own power to generate RF voltage under the control of the computer, and applies the RF voltage to the RF coil, so that the electrons further collide with the process gas in the RF enhanced discharge chamber to form high-density plasma; the high-density plasma is a plasma with a density higher than that of the initial plasma;

[0044] The screen grid DC regulated power supply and the accelerating grid DC regulated power supply adjust the voltage of the ion extraction grid to a voltage that meets the voltage requirement under the control of the computer, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam;

[0045] The Faraday cup measures the density of the ion beam;

[0046] The computer determines whether the density of the ion beam meets the stability requirement; the stability requirement is that the density of the ion beam output by the ion extraction grid meets the density requirement within a set time;

[0047] If yes, the ion beam current outputted by the ion extraction grid is determined as the target ion beam current for etching;

[0048] If not, each power supply is controlled to adjust the voltage or power until the density of the ion beam meets the stability requirement, thereby obtaining the target ion beam.

[0049] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0050] The present application discloses a microwave-radio frequency mixing coupled plasma discharge and modulation system and method, wherein process gas is respectively transported to an ECR zone and a radio frequency enhanced discharge chamber, and by adjusting the power of a microwave antenna, the voltage of an electron extraction grid and the radio frequency voltage, electrons in an initial plasma formed by discharge of process gas in the ECR zone further collide with process gas in the radio frequency enhanced discharge chamber to form a high-density plasma, and the density of the ion beam is judged according to the stability requirement to obtain a target ion beam for etching, and the system and method can overcome the problems of poor adaptability to electronegative gases, low ionization rate and plasma density, unclear discharge and modulation mechanism of microwave ion sources, and difficulty in stable control of existing radio frequency ion sources, and provide a microwave-radio frequency mixing coupled plasma discharge and modulation method, which can improve the adaptability of process gases, increase the gas ionization rate, and realize long-term, efficient and stable etching application of ion sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 A schematic diagram of the structure of a microwave-radio frequency mixing coupled plasma discharge and modulation system provided in one embodiment of the present application.

[0053] Reference numerals:

[0054] Metal shielding shell-1, first metal microwave shielding shell-2, microwave antenna-3, microwave static magnetic field-4, microwave discharge chamber-5, electron extraction grid-6, gas distributor-7, second metal microwave shielding shell-8, radio frequency coil-9, radio frequency enhanced discharge chamber-10, ion extraction grid-11, acceleration grid DC regulated power supply-12, screen grid DC regulated power supply-13, radio frequency power supply-14, electron extraction pole DC regulated power supply-15, solid-state microwave power supply-16, computer-17, gas distribution system-18, gas mass flowmeter-19, compressed gas cylinder-20, gas mixing tank-21. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] The purpose of this application is to provide a microwave-radio frequency mixing coupled plasma discharge and modulation system and method, aiming to achieve long-term, efficient and stable etching of the ion source.

[0057] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0058] In an exemplary embodiment, Figure 1 As shown, the microwave-RF mixing coupled plasma discharge and modulation system in this embodiment includes: a gas distribution system 18, multiple power supplies, an ion beam generating device, a Faraday cup and a computer 17; the multiple power supplies are: an accelerating grid DC regulated power supply 12, a screen grid DC regulated power supply 13, a radio frequency power supply 14, an electron extraction electrode DC regulated power supply 15 and a solid-state microwave power supply 16; the ion beam generating device includes: a metal shielding shell 1 with an open top and a first metal microwave shielding shell 2, a microwave antenna 3, a microwave static magnetic field 4, a microwave discharge chamber 5, an electron extraction grid 6, a gas distributor 7, a second metal microwave shielding shell 8, a radio frequency coil 9, a radio frequency enhanced discharge chamber 10 and an ion extraction grid 11; the second metal microwave shielding shell 8, the microwave antenna 3, the microwave static magnetic field 4, the microwave discharge chamber 5 and the electron extraction grid 6 together form an electron cyclotron resonance (Electron Cyclotron A Faraday cup is arranged in the exit direction of the ion beam of the ion extraction grid 11; the RF coil 9 surrounds the periphery of the RF enhanced discharge chamber 10.

[0059] The gas distribution system 18, the accelerating grid DC regulated power supply 12, the screen grid DC regulated power supply 13, the radio frequency power supply 14, the electron extraction electrode DC regulated power supply 15, the solid-state microwave power supply 16 and the Faraday cup are all connected to the computer 17; the gas distribution system 18 is connected to the gas distributor 7; the solid-state microwave power supply 16 is connected to the microwave antenna 3, the electron extraction electrode DC regulated power supply 15 is connected to the electron extraction grid 6, the radio frequency power supply 14 is connected to the radio frequency coil 9, and the accelerating grid DC regulated power supply 12 and the screen grid DC regulated power supply 13 are both connected to the ion extraction grid 11.

[0060] The computer 17 is used to obtain etching requirements and determine the proportion of process gases based on the etching requirements.

[0061] The gas distribution system 18 is used to store process gas and deliver the process gas to the gas distributor 7 according to the proportion.

[0062] The gas distributor 7 is used to deliver a portion of the process gas to the ECR region, and to deliver another portion of the process gas to the RF enhanced discharge chamber 10 .

[0063] The solid-state microwave power supply 16 is used to adjust its own power under the control of the computer 17, thereby adjusting the power of the microwave antenna 3, so that the process gas in the ECR zone discharges to form an initial plasma.

[0064] The electron extraction electrode DC regulated power supply 15 is used to adjust its own voltage under the control of the computer 17, thereby adjusting the voltage of the electron extraction grid 6 to extract the electrons in the initial plasma into the RF enhanced discharge chamber 10.

[0065] The RF power supply 14 is used to adjust its own power to generate RF voltage under the control of the computer 17, and load the RF voltage to the RF coil 9, so that the electrons further collide with the process gas in the RF enhanced discharge chamber 10 to form a high-density plasma; the high-density plasma is a plasma with a density higher than the initial plasma.

[0066] The screen grid DC regulated power supply 13 and the accelerating grid DC regulated power supply 12 are used to adjust the voltage of the ion extraction grid 11 to a voltage that meets the voltage requirements under the control of the computer 17, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam.

[0067] A Faraday cup is used to measure the density of an ion beam.

[0068] The computer 17 is also used for:

[0069] Determine whether the density of the ion beam meets the stability requirement; the stability requirement is that the density of the ion beam output by the ion extraction grid 11 meets the density requirement within a set time.

[0070] If so, the ion beam current output by the ion extraction grid 11 is determined as the target ion beam current for etching.

[0071] If not, each power supply is controlled to adjust the voltage or power until the density of the ion beam meets the stability requirement and the target ion beam is obtained.

[0072] In an exemplary embodiment, the total measurement time is n seconds, and it is assumed that the beam current density measured at the i-th second is j i , then the beam stability U J It can be expressed as:

[0073]

[0074] When U J When it is greater than the set value, the density of the ion beam output by the ion extraction grid meets the density requirement within the set time, and the density of the ion beam meets the stability requirement.

[0075] Different etching processes and etching samples have their own processing requirements. For example, the etching requirement for 100mm fused quartz grating is 1h, and the beam stability is better than 3%; the meter-level aperture element requires 8h, and the beam stability is better than 3%; the 1mm-level sample requires 1h at a fixed point, and the beam stability is better than 2%.

[0076] In an exemplary embodiment, the gas distribution system 18 includes: multiple compressed gas cylinders 20, multiple gas mass flow meters 19 and a gas mixing tank 21; one compressed gas cylinder 20 is connected to one gas mass flow meter 19, each compressed gas cylinder 20 is connected to the gas mixing tank 21, and the gas mixing tank 21 is connected to the gas distributor 7; each gas mass flow meter 19 is connected to the computer 17.

[0077] The computer 17 is also used for:

[0078] The gas mass flow rate of the corresponding compressed gas cylinder 20 collected by each gas mass flow meter 19 is obtained.

[0079] Based on the gas mass flow rate and ratio of each compressed gas cylinder 20 , each compressed gas cylinder 20 is controlled to deliver gas to the gas mixing tank 21 .

[0080] The gas mixing tank 21 is used to mix the gases delivered by the compressed gas cylinders 20 to obtain process gas, and deliver the process gas to the gas distributor 7 .

[0081] In an exemplary embodiment, circular holes are evenly distributed on the gas distributor 7, and the gas distributor 7 delivers process gas to the ECR region and the RF enhanced discharge chamber 10 simultaneously through the circular holes.

[0082] In an exemplary embodiment, the first metal microwave shielding shell 2 and the second metal microwave shielding shell 8 are made of stainless steel or aluminum alloy.

[0083] In an exemplary embodiment, the microwave antenna 3 can be designed as a circular plate, a circular ring or other shapes that are conducive to microwave energy feeding. The material is metal molybdenum or metal copper, and the frequency of the microwave antenna 3 can be selected from 1GHz to 15GHz according to the needs.

[0084] In an exemplary embodiment, the microwave static magnetic field 4 is composed of an annular multi-pole high temperature resistant fir cobalt magnet, and the magnetic field intensity of the microwave static magnetic field 4 is greater than 875 GS.

[0085] In an exemplary embodiment, the microwave discharge chamber 5 is made of quartz or ceramic material.

[0086] In an exemplary embodiment, the electron extraction grid 6 is composed of graphite or molybdenum grid.

[0087] In an exemplary embodiment, the ion extraction grid 11 includes: a screen grid, an acceleration grid and a deceleration grid arranged from bottom to top.

[0088] The accelerating grid DC regulated power supply 12 is connected to the accelerating grid; the screen grid DC regulated power supply 13 is connected to the screen grid.

[0089] In an exemplary embodiment, the ion extraction grid 11 is made of a conductive material; the conductive material includes molybdenum, stainless steel and graphite.

[0090] In an exemplary embodiment, the RF coil 9 is a copper spiral cylindrical coil.

[0091] In an exemplary embodiment, the microwave-RF mixing coupled plasma discharge and modulation method in this embodiment is implemented based on a microwave-RF mixing coupled plasma discharge and modulation system, and the microwave-RF mixing coupled plasma discharge and modulation method includes:

[0092] The computer obtains the etching requirements and determines the proportion of process gases based on the etching requirements.

[0093] The gas distribution system delivers process gas to the gas distributor according to the ratio.

[0094] The gas distributor delivers a portion of the process gas to the ECR zone and another portion of the process gas to the RF enhanced discharge chamber.

[0095] The solid-state microwave power supply adjusts its own power under the control of the computer, thereby adjusting the power of the microwave antenna, so that the process gas in the ECR zone discharges to form an initial plasma.

[0096] The electron extraction electrode DC regulated power supply adjusts its own voltage under the control of the computer, thereby adjusting the voltage of the electron extraction grid to extract the electrons in the initial plasma into the RF enhanced discharge chamber.

[0097] The RF power supply adjusts its own power under the control of a computer to generate RF voltage, and loads the RF voltage to the RF coil, so that the electrons further collide with the process gas in the RF enhanced discharge chamber to form a high-density plasma; a high-density plasma is a plasma with a density higher than that of the initial plasma.

[0098] The screen grid DC regulated power supply and the accelerating grid DC regulated power supply adjust the voltage of the ion extraction grid to a voltage that meets the voltage requirements under the control of the computer, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam.

[0099] The Faraday cup measures the density of the ion beam.

[0100] The computer determines whether the density of the ion beam meets the stability requirement; the stability requirement is that the density of the ion beam output by the ion extraction grid meets the density requirement within a set time.

[0101] If so, the ion beam current output by the ion extraction grid is determined as the target ion beam current for etching.

[0102] If not, each power supply is controlled to adjust the voltage or power until the density of the ion beam meets the stability requirement and the target ion beam is obtained.

[0103] Taking the etching of a fused quartz grating substrate of 85mm×85mm×1mm, with a process gas ratio of CHF3:12sccm, O2:2sccm, Ar:1sccm as an example, the microwave-RF mixing coupled plasma discharge and modulation method is further described in detail. The implementation steps include:

[0104] Step 1: Determine the type and ratio of process gas according to relevant literature or etching requirements; use gas mass flow meter to control the gas flow rate, which are CHF3: 12sccm, O2: 2sccm, Ar: 1sccm.

[0105] Step 2: After the process gas is evenly mixed in the gas mixing tank, open the solenoid stop valve to direct the gas to the ECR area.

[0106] Step 3: Select the microwave frequency band as 2.45 GHz, adjust the power of the solid-state microwave power supply to 50 W, and thereby adjust the power of the microwave antenna to discharge the process gas to form an initial plasma.

[0107] Step 4: Adjust the voltage of the electron extraction electrode DC regulated power supply, thereby adjusting the voltage of the electron extraction grid, and extracting the electrons in the initial plasma into the RF enhanced discharge chamber.

[0108] Step 5: Select the RF frequency band as 13.56MHz, adjust the RF power supply power to 100W, generate RF voltage, and load the RF voltage to the RF coil, so that the electrons further collide with the process gas in the RF enhanced discharge chamber to form a high-density plasma. After the reflected power drops below 5W, observe the plasma state in the RF enhanced discharge chamber. After the plasma brightness stabilizes, proceed to step 6.

[0109] Step 6: The screen grid DC regulated power supply and the accelerating grid DC regulated power supply adjust the screen grid voltage in the ion extraction grid to 500V and the accelerating grid voltage to -100V, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam.

[0110] Step 7: Use a Faraday cup to measure the density of the ion beam.

[0111] Step 8: Determine whether the density of the ion beam current meets the stability requirement. If it does, proceed to step 9. If it does not, return to step 3.

[0112] Step 9: Determine the ion beam current output by the ion extraction grid as the target ion beam current for etching.

[0113] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the system, method and core ideas of this application; at the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A microwave-radio frequency mixing coupled plasma discharge and modulation system, characterized in that: The microwave-RF mixing coupled plasma discharge and modulation system comprises: a gas distribution system, multiple power supplies, an ion beam generating device, a Faraday cup and a computer; the multiple power supplies are respectively: an accelerating grid DC regulated power supply, a screen grid DC regulated power supply, a radio frequency power supply, an electron extraction pole DC regulated power supply and a solid-state microwave power supply; the ion beam generating device comprises: a metal shielding shell with an open top and a first metal microwave shielding shell arranged inside the metal shielding shell, a microwave antenna, a microwave static magnetic field, a microwave discharge chamber, an electron extraction grid, a gas distributor, a second metal microwave shielding shell, a radio frequency coil, a radio frequency enhanced discharge chamber and an ion extraction grid; the second metal microwave shielding shell, the microwave antenna, the microwave static magnetic field, the microwave discharge chamber and the electron extraction grid together form an ECR area; a Faraday cup is arranged in the emission direction of the ion beam of the ion extraction grid; the radio frequency coil surrounds the periphery of the radio frequency enhanced discharge chamber; The gas distribution system, the accelerating grid DC regulated power supply, the screen grid DC regulated power supply, the radio frequency power supply, the electron extraction pole DC regulated power supply, the solid-state microwave power supply and the Faraday cup are all connected to the computer; the gas distribution system is in communication with the gas distributor; the solid-state microwave power supply is connected to the microwave antenna, the electron extraction pole DC regulated power supply is connected to the electron extraction grid, the radio frequency power supply is connected to the radio frequency coil, and the accelerating grid DC regulated power supply and the screen grid DC regulated power supply are both connected to the ion extraction grid; The computer is used to obtain etching requirements and determine the ratio of process gases based on the etching requirements; The gas distribution system is used to store process gas and deliver process gas to the gas distributor according to the ratio; The gas distributor is used to deliver a portion of the process gas to the ECR area and another portion of the process gas to the RF enhanced discharge chamber; The solid-state microwave power supply is used to adjust its own power under the control of the computer, thereby adjusting the power of the microwave antenna, so that the process gas in the ECR zone discharges to form an initial plasma; The electron extraction electrode DC regulated power supply is used to adjust its own voltage under the control of the computer, thereby adjusting the voltage of the electron extraction grid, and extracting the electrons in the initial plasma into the radio frequency enhanced discharge chamber; The RF power supply is used to adjust its own power to generate RF voltage under the control of the computer, and load the RF voltage to the RF coil, so that the electrons further collide with the process gas in the RF enhanced discharge chamber to form high-density plasma; the high-density plasma is a plasma with a density higher than that of the initial plasma; The screen grid DC regulated power supply and the accelerating grid DC regulated power supply are used to adjust the voltage of the ion extraction grid to a voltage that meets the voltage requirement under the control of the computer, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam; The Faraday cup is used to measure the density of the ion beam; The computer is also used to: Determine whether the density of the ion beam meets the stability requirement; the stability requirement is that the density of the ion beam output by the ion extraction grid meets the density requirement within a set time; If yes, the ion beam current output by the ion extraction grid is determined as the target ion beam current for etching; If not, each power supply is controlled to adjust the voltage or power until the density of the ion beam meets the stability requirement, thereby obtaining the target ion beam.

2. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The gas distribution system comprises: a plurality of compressed gas cylinders, a plurality of gas mass flow meters and a gas mixing tank; one of the compressed gas cylinders is connected to one of the gas mass flow meters, each of the compressed gas cylinders is connected to the gas mixing tank, and the gas mixing tank is connected to the gas distributor; each of the gas mass flow meters is connected to the computer; The computer is also used to: Obtaining the gas mass flow rate of the corresponding compressed gas cylinder collected by each of the gas mass flow meters; Controlling each of the compressed gas cylinders to deliver gas to the gas mixing tank based on the gas mass flow rate of each compressed gas cylinder and the ratio; The gas mixing tank is used to mix the gases delivered by the compressed gas cylinders to obtain process gas, and deliver the process gas to the gas distributor.

3. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The gas distributor is evenly distributed with circular holes, and the gas distributor simultaneously delivers process gas to the ECR area and the radio frequency enhanced discharge chamber through the circular holes.

4. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The first metal microwave shielding shell and the second metal microwave shielding shell are made of stainless steel or aluminum alloy.

5. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The microwave static magnetic field is composed of annular multi-pole high temperature resistant fir cobalt magnets, and the magnetic field intensity of the microwave static magnetic field is greater than 875GS.

6. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The microwave discharge chamber is made of quartz or ceramic material.

7. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The electron extraction grid is composed of graphite or molybdenum grid.

8. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The ion extraction grid includes: a screen grid, an acceleration grid and a deceleration grid arranged from bottom to top; The acceleration grid DC regulated power supply is connected to the acceleration grid; the screen grid DC regulated power supply is connected to the screen grid.

9. The microwave-RF mixing coupled plasma discharge and modulation system according to claim 1, characterized in that: The ion extraction grid is made of a conductive material; the conductive material includes molybdenum, stainless steel and graphite.

10. A microwave-RF mixing coupled plasma discharge and modulation method, implemented based on the microwave-RF mixing coupled plasma discharge and modulation system according to any one of claims 1 to 9, characterized in that: The microwave-radio frequency mixing coupled plasma discharge and modulation method comprises: The computer obtains the etching requirement and determines the ratio of the process gas based on the etching requirement; The gas distribution system delivers process gas to the gas distributor according to the ratio; The gas distributor delivers a portion of the process gas to the ECR zone and another portion of the process gas to the RF enhanced discharge chamber; The solid-state microwave power supply adjusts its own power under the control of the computer, thereby adjusting the power of the microwave antenna, so that the process gas in the ECR zone discharges to form an initial plasma; The electron extraction electrode DC regulated power supply adjusts its own voltage under the control of the computer, thereby adjusting the voltage of the electron extraction grid, and extracting the electrons in the initial plasma into the radio frequency enhanced discharge chamber; The RF power supply adjusts its own power to generate RF voltage under the control of the computer, and applies the RF voltage to the RF coil, so that the electrons further collide with the process gas in the RF enhanced discharge chamber to form high-density plasma; the high-density plasma is a plasma with a density higher than that of the initial plasma; The screen grid DC regulated power supply and the accelerating grid DC regulated power supply adjust the voltage of the ion extraction grid to a voltage that meets the voltage requirement under the control of the computer, so that the ions in the high-density plasma are accelerated and extracted to form an ion beam; The Faraday cup measures the density of the ion beam; The computer determines whether the density of the ion beam meets the stability requirement; the stability requirement is that the density of the ion beam output by the ion extraction grid meets the density requirement within a set time; If yes, the ion beam current outputted by the ion extraction grid is determined as the target ion beam current for etching; If not, each power supply is controlled to adjust the voltage or power until the density of the ion beam meets the stability requirement, thereby obtaining the target ion beam.

Images