Multifunctional wide-density plasma discharge method

Abstract

The invention discloses a multifunctional wide-density plasma discharge method, and relates to the technical field of plasmas, and the method comprises the steps: S1, system design and construction; s2, switching a plasma discharge mode; s3, plasma-assisted chemical vapor deposition is carried out; s4, plasma-assisted atomic layer deposition; and S5, system performance optimization and verification. According to the multifunctional wide-density plasma discharge method and the flexible plasma system, the plasma density is relatively low, and the plasma electric field is controllable, so that the damage to the substrate in the plasma treatment or deposition process can be inhibited. Meanwhile, three main defects of long-distance plasmas are overcome: firstly, a relatively high processing rate can be ensured; and secondly, the plasma is controllable, so that the device not only can work in a capacitive discharge mode, but also can work in a transition region mode between capacitive discharge and inductive discharge, and even can work in an inductive discharge mode. And thirdly, the cost is low.

Description

Technical Field

[0001] The invention relates to the field of plasma technology, in particular to a multifunctional wide-density plasma discharge method. Background Art

[0002] Amidst today's rapid technological advancements, plasma technology, as a key material processing and surface treatment tool, has demonstrated broad application potential in diverse fields, including semiconductor manufacturing, solar cells, and display manufacturing. Plasma, by creating a highly reactive gas environment, effectively enables processes such as material etching, thin film deposition, and surface modification. With the rapid advancement of technology, demand for plasma technology is growing, particularly for high-precision and low-damage processing. The global plasma technology market is experiencing rapid growth.

[0003] Currently, the most common plasmas on the market include planar capacitively coupled plasma (CCP), inductively coupled plasma (ICP), and microwave plasma (MP). However, in practical applications, these plasma discharges have the following drawbacks:

[0004] Flat plate capacitively coupled plasma: The alternating electric field of CCP is perpendicular to the sample surface, which can easily cause damage to the processed material. Although the plasma density of CCP is low (1010cm -3 ), but problems with the direction of the electric field limit its use in certain high-precision applications.

[0005] Inductively coupled plasma: ICP has a very high plasma density (1013cm -3 ), positive ions can move in different directions under the action of electromagnetic fields, which can easily cause excessive damage to the sample, and ICP is more suitable for plasma etching, surface texturing and wafer cleaning, but performs poorly in applications that require low-damage processing.

[0006] Microwave plasma: There are limitations on the density and uniformity of microwave plasma. Although it has a high degree of ionization, the discharge area is concentrated, making it difficult to maintain uniformity in large-area processing. In addition, microwave plasma equipment is usually more complex, with high maintenance and operating costs. Summary of the Invention

[0007] The object of the present invention is to provide a multifunctional wide-density plasma discharge method to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a multifunctional wide-density plasma discharge method, comprising the following steps:

[0009] S1. System Design and Construction: Design and construct a flexible plasma (CCEP) system with a high-frequency RF power supply, a planar helical coil, a matching tuning network, and a vacuum and operating system;

[0010] S2. Plasma discharge mode switching: By adjusting the input power and matching network, free switching between capacitive discharge (E-mode), inductive discharge (H-mode) and the transition zone mode between the two is achieved;

[0011] S3, Plasma-assisted Chemical Vapor Deposition (PECVD): Chemical vapor deposition of high-quality thin films using a flexible plasma system;

[0012] S4. Plasma-assisted atomic layer deposition (PEALD): Atomic layer deposition of two-dimensional materials or high-quality thin films using a flexible plasma system;

[0013] S5. System performance optimization and verification: Measure plasma parameters using a Langmuir probe, optimize system performance, and conduct application verification.

[0014] Furthermore, the step S1 specifically includes the following operations:

[0015] RF power supply: Use a low-frequency RF power supply with a frequency of 0.5-2MHz to achieve stable capacitor discharge (E-mode);

[0016] Antenna Design: Use a planar helical coil with high capacitance, such as a planar circular incense coil or a planar rectangular helical coil, designed to achieve stable capacitive discharge (E-mode) at low-frequency (0.5-2 MHz) RF power.

[0017] Matching tuning network: Design a tuned impedance matching network to ensure that the matching network (tuning capacitance) is greater than 10pF to achieve capacitor discharge;

[0018] Vacuum and operating system: Build a vacuum chamber and corresponding gas control system to ensure that the vacuum degree and gas flow are controllable during the processing process.

[0019] Furthermore, the capacitance range of the matching network is: fixed capacitance 5-100 nanofarads (nF), and tuning capacitance 10-6010 picofarads (pF).

[0020] Furthermore, in step S2, the plasma discharge mode includes a capacitive discharge mode, an inductive discharge mode, and a transition zone mode. The input power and plasma density of each mode are as follows:

[0021] Capacitor discharge mode: input power 1-100W, plasma density 10 8 ~10 9 cm-3 , whose radial electric field is parallel to the sample surface;

[0022] Inductive discharge mode: input power>500W, plasma density 10 13 cm -3 ;

[0023] Transition zone mode: input power 100-500W, plasma density between 10 11 cm -3 .

[0024] Furthermore, the specific operation of step S3 is as follows: introducing precursor gas (such as silane, ammonia, etc.) through a gas control system, and adjusting the power of the RF power supply to an appropriate level to excite plasma, and performing thin film deposition on the substrate surface, and the deposition temperature is controlled in the range of 0 to 400°C, and the deposition time is adjusted according to the required film thickness and deposition rate.

[0025] Furthermore, the step S4 specifically includes the following operations:

[0026] Precursor pulses: Alternating between different precursor pulses, where the precursors are selected based on the deposition material, such as trimethylaluminum (TMA) and ammonia (NH3) for depositing aluminum nitride (AlN);

[0027] Plasma excitation: After each precursor pulse, a plasma (such as argon plasma) is excited to clean the unreacted precursor from the surface;

[0028] Cyclic deposition: The precursor pulse and plasma clean steps are repeated for a number of cycles determined by the desired film thickness until the desired film thickness is achieved.

[0029] Furthermore, in step S5, a Langmuir probe is used to measure the electron concentration distribution function, electron concentration and average electron temperature under different input powers (such as 20W, 30W, 50W, etc.), and performance optimization is performed based on the measurement results.

[0030] Furthermore, the performance optimization aims to achieve low-damage, high-density or transition zone plasma discharge to meet different application requirements. Specifically, the plasma density and electric field distribution are optimized by adjusting the RF power supply power, matching network parameters, etc.

[0031] Furthermore, in step S5, the application verification indicators include film quality (such as uniformity, thickness, defect density, etc.) and surface modification effect (such as doping concentration, phase change degree, etc.). The specific operation is: performing thin film deposition or surface modification experiments on the optimized system to verify the system performance.

[0032] The present invention provides a multifunctional wide-density plasma discharge method, which has the following beneficial effects:

[0033] The flexible plasma system of the present invention not only has a low plasma density but also a controllable plasma electric field, thereby suppressing damage to the substrate during plasma treatment or deposition. It also overcomes the three main drawbacks of remote plasma:

[0034] First, it can ensure a higher processing rate. The density of the flexible plasma of the present invention is lower, but still higher than that of the remote plasma, which can ensure a higher deposition or etching rate.

[0035] Second, the plasma is controllable. The flexible plasma of the present invention can operate not only in the capacitive discharge (E-mode) mode of 1-100W, where the plasma density varies with input power, but also in the transition zone between capacitive discharge (E-mode) and inductive discharge (H-mode) of approximately 100-500W, and even in inductive discharge (H-mode) above 500W.

[0036] Third, it offers lower costs. The flexible plasma system of our invention is similar to ICP, with equipment costs roughly on par with ICP. Therefore, our flexible plasma system can be applied to plasma-assisted atomic layer deposition (PAAD) for self-aligned multi-patterning (SMP) in the silicon-based semiconductor industry, plasma-assisted ALD and surface modification of two-dimensional semiconductors, and chemical vapor deposition (CVD) of amorphous silicon thin films for HIT solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic flow chart of the steps of a multifunctional wide-density plasma discharge method of the present invention;

[0038] Figure 2 A schematic diagram of the radial electric field in a capacitive discharge mode of a multifunctional wide-density plasma discharge method of the present invention;

[0039] Figure 3 A schematic diagram comparing the densities of different types of plasmas in a multifunctional wide-density plasma discharge method according to the present invention;

[0040] Figure 4 This is a graph showing the electron concentration distribution function of CCEP of a multifunctional wide-density plasma discharge method of the present invention at 20W, 30W and 50W radio frequency powers;

[0041] Figure 5 This is a diagram of electron concentration and average electron temperature of CCEP of a multifunctional wide-density plasma discharge method of the present invention at 20W, 30W and 50W radio frequency powers.

[0042] Figure 6Schematic diagram comparing the technical indicators, functions and uses of CCEP, a flexible plasma system with a multifunctional wide-density plasma discharge method of the present invention, with plasma systems on the domestic and foreign markets. DETAILED DESCRIPTION

[0043] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0044] like Figures 1-6 As shown, a multifunctional wide-density plasma discharge method comprises the following steps:

[0045] S1. System Design and Construction: Design and construct a flexible plasma (CCEP) system with a high-frequency radio frequency power supply, a planar spiral coil, a matching tuning network, and a vacuum and operating system. This step specifically includes the following operations:

[0046] RF power supply: Use a low-frequency RF power supply with a frequency of 0.5-2MHz to achieve stable capacitor discharge (E-mode);

[0047] Antenna Design: Use a planar helical coil with high capacitance, such as a planar circular incense coil or a planar rectangular helical coil. The coil is designed to achieve stable capacitive discharge (E-mode) under low-frequency (0.5-2MHz) RF power supply.

[0048] Matching tuning network: Design a tuned impedance matching network to ensure that the matching network (tuning capacitor) is greater than 10pF to achieve capacitor discharge. The matching network capacitance range is: fixed capacitance 5-100 nanofarads (nF), tuning capacitance 10-6010 picofarads (pF);

[0049] Vacuum and operating system: Build a vacuum chamber and corresponding gas control system to ensure that the vacuum degree and gas flow are controllable during the processing process.

[0050] S2. Plasma discharge mode switching: By adjusting the input power and matching network, free switching between capacitive discharge (E-mode), inductive discharge (H-mode) and the transition zone mode between the two can be achieved.

[0051] In this embodiment, the plasma discharge modes include capacitive discharge mode, inductive discharge mode, and transition zone mode. The input power and plasma density of each mode are as follows:

[0052] Capacitor discharge mode: input power 1-100W, plasma density 10 8 ~10 9 cm -3 , whose radial electric field is parallel to the sample surface, such as Figure 2 As shown;

[0053] Inductive discharge mode: input power>500W, plasma density 10 13 cm -3 ;

[0054] Transition zone mode: input power 100-500W, plasma density between 10 11 cm -3 .

[0055] S3. Plasma-assisted chemical vapor deposition (PECVD): Utilizes a flexible plasma system for chemical vapor deposition of high-quality thin films. Specifically, precursor gases (such as silane, ammonia, etc.) are introduced through a gas control system, and the RF power is adjusted to an appropriate level to excite plasma and deposit thin films on the substrate surface. The deposition temperature is controlled within the range of 0 to 400°C, and the deposition time is adjusted according to the required film thickness and deposition rate.

[0056] S4, Plasma Assisted Atomic Layer Deposition (PEALD): Atomic layer deposition of two-dimensional materials or high-quality thin films is performed using a flexible plasma system. This step specifically includes the following operations:

[0057] Precursor pulses: Alternately introduce different precursor pulses. The precursor is selected according to the deposition material, such as trimethylaluminum (TMA) and ammonia (NH3) for depositing aluminum nitride (AlN);

[0058] Plasma excitation: After each precursor pulse, a plasma (such as argon plasma) is excited to clean the unreacted precursor from the surface;

[0059] Cyclic deposition: The precursor pulse and plasma clean steps are repeated for a number of cycles determined by the desired film thickness until the desired film thickness is achieved.

[0060] S5. System performance optimization and verification: Measure plasma parameters using a Langmuir probe, optimize system performance, and conduct application verification.

[0061] In this embodiment, a Langmuir probe is used to measure the electron concentration distribution function, electron concentration, and average electron temperature at input powers of 20 W, 30 W, and 50 W, and performance optimization is performed based on the measurement results. The performance optimization aims to achieve low-damage, high-density, or transition zone plasma discharge to meet different application requirements. Specifically, the plasma density and electric field distribution are optimized by adjusting the RF power supply power, matching network parameters, etc.

[0062] In this embodiment, the application verification indicators include film quality (such as uniformity, thickness, defect density, etc.) and surface modification effect (such as doping concentration, phase change degree, etc.). The specific operation is: thin film deposition or surface modification experiments are performed on the optimized system to verify the system performance.

[0063] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A multifunctional wide-density plasma discharge method, characterized in that: The following steps are involved: S1. System Design and Construction: Design and construct a flexible plasma system with a high-frequency radio frequency power supply, a planar spiral coil, a matching tuning network, and a vacuum and operating system; S2. Plasma discharge mode switching: By adjusting the input power and matching network, free switching between capacitive discharge, inductive discharge and the transition zone mode between the two is achieved; S3, Plasma-Assisted Chemical Vapor Deposition: Utilizes flexible plasma systems for chemical vapor deposition of high-quality thin films; S4, Plasma-Assisted Atomic Layer Deposition: Atomic layer deposition of two-dimensional materials or high-quality thin films using a flexible plasma system; S5. System performance optimization and verification: Measure plasma parameters using a Langmuir probe, optimize system performance, and conduct application verification.

2. A multifunctional wide-density plasma discharge method according to claim 1, characterized in that: The step S1 specifically includes the following operations: RF power supply: Use a low-frequency RF power supply with a frequency of 0.5-2MHz to achieve stable capacitor discharge; Antenna Design: A planar helical coil with high capacitance is used to achieve stable capacitance discharge under low-frequency RF power. Matching tuning network: Design a tuned impedance matching network to ensure that the matching network is greater than 10pF to achieve capacitor discharge; Vacuum and operating system: Build a vacuum chamber and corresponding gas control system to ensure that the vacuum degree and gas flow are controllable during the processing process.

3. A multifunctional wide-density plasma discharge method according to claim 2, characterized in that: The capacitance range of the matching network is: fixed capacitance 5-100nF, tuning capacitance 10-6010pF.

4. The multifunctional wide-density plasma discharge method according to claim 1, characterized in that: In step S2, the plasma discharge mode includes a capacitive discharge mode, an inductive discharge mode, and a transition zone mode. The input power and plasma density of each mode are as follows: Capacitor discharge mode: input power 1-100W, plasma density 10 8 ~10 9 cm -3 , whose radial electric field is parallel to the sample surface; Inductive discharge mode: input power>500W, plasma density 10 13 cm -3 ; Transition zone mode: input power 100-500W, plasma density between 10 11 cm -3 .

5. The multifunctional wide-density plasma discharge method according to claim 1, characterized in that: The specific operation of step S3 is as follows: introducing precursor gas through a gas control system, adjusting the power of the radio frequency power supply to an appropriate level, exciting plasma, and performing thin film deposition on the substrate surface, and controlling the deposition temperature within the range of 0 to 400°C.

6. The multifunctional wide-density plasma discharge method according to claim 1, characterized in that: The step S4 specifically includes the following operations: Precursor pulses: alternately introducing pulses of different precursors, wherein the precursors are selected according to the deposition material; Plasma excitation: After each precursor pulse, plasma is ignited to clean the surface of unreacted precursors; Cyclic deposition: Precursor pulses and plasma purge steps are repeated until the desired film thickness is achieved.

7. The multifunctional wide-density plasma discharge method according to claim 1, characterized in that: In step S5, a Langmuir probe is used to measure the electron concentration distribution function, electron concentration and average electron temperature at different input powers, and performance optimization is performed based on the measurement results.

8. The multifunctional wide-density plasma discharge method according to claim 7, characterized in that: The performance optimization is aimed at achieving low-damage, high-density or transition zone plasma discharge to meet different application requirements. Specifically, the plasma density and electric field distribution are optimized by adjusting the RF power supply power and matching network parameters.

9. The multifunctional wide-density plasma discharge method according to claim 1, characterized in that: In step S5, the application verification indicators include film quality and surface modification effect. The specific operation is: performing a thin film deposition or surface modification experiment on the optimized system to verify the system performance.

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