Plasma processing apparatus and processing method

Abstract

The application provides a kind of plasma processing device, including a vacuum reaction cavity, the electrically conductive pedestal is arranged in the vacuum reaction cavity;A main radio frequency transmission rod is electrically connected with at least one radio frequency power supply, for applying the first radio frequency signal to the electrically conductive pedestal;Edge ring is arranged around the pedestal;A edge radio frequency transmission line is arranged below the edge ring, the edge radio frequency transmission line applies the second radio frequency signal to the edge ring by an impedance adjusting module, the impedance adjusting module is located in the atmospheric environment below the electrically conductive pedestal, and includes at least one high-voltage adjustable capacitor component;The part of the edge radio frequency transmission line located inside the vacuum reaction cavity is sleeved with a dielectric sleeve;The main radio frequency transmission rod includes a hollow structure, and the edge radio frequency transmission line is at least partially located inside the main radio frequency transmission rod.The edge radio frequency adjusting mechanism of the application can actively adjust the sheath height above the edge ring, and can adapt to a higher voltage radio frequency environment.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, and more specifically to a plasma processing technology with edge radio frequency modulation function. Background Technology

[0002] Semiconductor chips are increasingly widely used in various electronic devices. The semiconductor chip manufacturing process requires numerous plasma processors, which perform processes such as plasma etching and chemical vapor deposition on the substrate. A typical plasma processor usually includes at least one vacuum reaction chamber. A base is positioned below the vacuum reaction chamber to support the substrate. An external radio frequency (RF) power supply applies an RF signal to the base, creating an RF environment within the reaction chamber. The vacuum reaction chamber also includes a gas inlet device that delivers process gases according to specific process requirements. These process gases are dissociated into plasma in the RF environment, achieving the etching or deposition process on the substrate.

[0003] To achieve uniform substrate processing, an edge ring assembly is required around the substrate. By selecting the material and dimensions of the edge ring assembly, the coupling RF energy and temperature distribution in the substrate edge region can be altered. The edge ring assembly includes a focusing ring, the upper surface of which is exposed to the plasma above. During plasma processing, bias RF power is used to control the sheath thickness formed on the upper surfaces of the substrate and the focusing ring. The sheath thickness determines the energy and direction of ions incident on the substrate from the plasma. If the sheaths in the substrate edge region and the focusing ring are discontinuously distributed, it will cause differences in etching rate and edge tilting between the substrate edge region and the substrate center region, reducing substrate processing uniformity and affecting the final chip yield.

[0004] Since the focusing ring is permanently immersed in plasma filled with etching gas, its surface material will inevitably corrode after a certain period of plasma treatment. Consequently, the height of the focusing ring's upper surface will decrease, significantly affecting the distribution and morphology of the sheath layer in the substrate edge region. Therefore, the industry needs to develop a new adjustment device to achieve micro-precision adjustment of the RF power distribution in the substrate center and edge regions, thereby improving the uniformity of the substrate processing. Ideally, this adjustment device should be simple in structure, low in cost, and applicable to various plasma processing devices. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a plasma processing apparatus, comprising a vacuum reaction chamber, within which a lower electrode assembly is disposed, the lower electrode assembly including a conductive base; a main radio frequency (RF) transmission rod electrically connected to at least one RF power supply for applying a first RF signal to the conductive base, the main RF transmission rod including a hollow structure; an edge ring surrounding the lower electrode assembly; an impedance adjustment module located in the atmospheric environment below the conductive base, including at least one high-voltage adjustable capacitor assembly; and an edge RF transmission line applying a second RF signal to the edge ring via the impedance adjustment module, the edge RF transmission line in the vacuum environment being fitted with a dielectric sleeve, and the edge RF transmission line in the atmospheric environment being at least partially located inside the hollow structure of the main RF transmission rod. This invention, by providing an edge RF adjustment mechanism below the edge ring, can actively adjust the RF distribution in the edge region, compensating for the uneven processing of the wafer edge and center regions caused by edge ring wear during process advancement.

[0006] Optionally, a radio frequency distribution ring is provided below the edge ring, and the edge radio frequency transmission line is electrically connected to the radio frequency distribution ring.

[0007] Optionally, the radio frequency distribution ring is conductive, including a conductor material or a semiconductor material.

[0008] Optionally, the surface of the radio frequency distribution ring is provided with an insulating coating.

[0009] Optionally, a graphite coating is provided above the radio frequency distribution ring.

[0010] Optionally, the edge radio frequency transmission line includes a plurality of conductive rods, which are electrically connected to the radio frequency distribution loop uniformly or non-uniformly.

[0011] Optionally, the impedance adjustment module includes multiple fixed capacitors connected in parallel, and each fixed capacitor is provided with a high-voltage resistant vacuum relay.

[0012] Optionally, the impedance adjustment module includes a motor capacitor.

[0013] Optionally, the radio frequency power supply includes a radio frequency power supply having a first frequency and a radio frequency power supply having a second frequency.

[0014] Optionally, the second radio frequency signal has a second frequency.

[0015] Optionally, an RF filter is provided between the main RF transmission rod and the edge RF transmission line, and the RF filter is used to filter the RF signal of the first frequency.

[0016] Optionally, the output voltage of the second frequency radio frequency power supply is greater than or equal to 8KV.

[0017] Optionally, the output power of the second frequency radio frequency power supply is greater than or equal to 10KW.

[0018] Optionally, the second frequency is lower than the first frequency.

[0019] Optionally, the second frequency is less than or equal to 2MHz.

[0020] Optionally, the second frequency is less than or equal to 1 MHz.

[0021] Optionally, a mounting plate is disposed below the conductive base, and the main radio frequency transmission rod is electrically connected to the mounting plate.

[0022] Optionally, the dielectric sleeve is made of high-purity ceramic, and the purity of the ceramic is greater than 95%.

[0023] Optionally, the distance between the inner diameter of the dielectric sleeve and the edge radio frequency transmission line is less than or equal to 0.3 mm.

[0024] Optionally, the dielectric sleeve includes a plurality of ceramic insulating elements, and a groove assembly is provided on the mating surface between two adjacent ceramic insulating elements to prevent breakdown.

[0025] Optionally, the edge ring is a focusing ring.

[0026] Furthermore, the present invention also discloses a plasma processing method with edge impedance adjustment function, wherein the method is performed in the plasma processing apparatus described above, and the method includes the following steps:

[0027] Substrate etching effect monitoring steps: Detect the etching effect in the edge area of ​​the substrate. If the tilt angle of the etching hole at the edge of the substrate is within the preset angle range, continue to execute the substrate etching effect detection step. If the tilt angle of the etching hole at the edge of the substrate exceeds the preset threshold, proceed to the variable impedance adjustment step.

[0028] Variable impedance adjustment step: Adjust the capacitance value of the high voltage adjustable capacitor component to change the impedance of the impedance adjustment module, thereby changing the RF power delivered to the substrate edge ring, and then re-enter the substrate etching effect monitoring step.

[0029] This invention incorporates an edge adjustment mechanism below the edge ring, specifically including: a radio frequency (RF) distribution ring below the focusing ring, connected to an edge RF transmission line; the edge RF transmission line introduces an RF signal to the RF distribution ring via a high-voltage impedance adjustment module, and the RF distribution ring couples the RF signal to the focusing ring to adjust the edge electric field and plasma distribution in the edge region. The impedance adjustment module of this invention is located in the atmospheric environment outside the vacuum reaction chamber, allowing it to withstand high RF voltages. Simultaneously, to accommodate the high-voltage environment of the vacuum reaction chamber, the edge RF transmission line in the vacuum environment is fitted with a high-purity dielectric sleeve to isolate high-power signals from the lower electrode assembly.

[0030] In addition, at least a portion of the edge RF transmission lines of this invention are located inside the hollow structure of the main RF transmission rod. Placing the edge RF transmission lines inside the hollow main RF transmission rod helps ensure the symmetry of high-frequency RF power transmission in the circumferential direction, as the high-frequency RF current is distributed outside the main RF transmission rod due to the high-frequency skin effect. Placing the edge transmission lines inside the hollow main RF transmission rod helps minimize the impact on the high-frequency RF transmission loop. Furthermore, since the impedance adjustment module is located outside the vacuum reaction chamber and far from the focusing ring, placing the edge RF transmission lines leading from the impedance adjustment module inside the hollow main RF transmission rod allows for a shorter length of the edge RF transmission lines, while also simplifying the wiring below the mounting plate. Attached Figure Description

[0031] Figure 1 A schematic diagram of a capacitively coupled plasma processing device is shown.

[0032] Figure 2 The following diagram shows an enlarged view of the edge region of the electrode assembly;

[0033] Figure 3A and Figure 3B Schematic diagrams of two different embodiments of the contact interface between the RF distribution ring and the focusing ring are shown respectively;

[0034] Figure 4 A schematic diagram of an inductively coupled plasma processing device is shown. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The plasma processing device described in the technical solution of the present invention can be either a capacitively coupled plasma processing device (CCP) or an inductively coupled plasma processing device (ICP). Figure 1 A schematic diagram of a capacitively coupled plasma processing device is shown, as follows: Figure 1 As shown, the plasma processing apparatus has a vacuum reaction chamber 100, which is substantially cylindrical with substantially vertical sidewalls. The vacuum reaction chamber 100 contains an upper electrode assembly 110 and a lower electrode assembly 120 disposed opposite to each other. Typically, the upper electrode assembly 110 includes a spray head for supplying process gas into the reaction chamber 100, and the lower electrode assembly 120 includes a conductive base 122, an electrostatic adsorption layer 124 above the conductive base, and a mounting plate 126 below the conductive base. The electrostatic adsorption layer 124 is used to support and adsorb the wafer W to be processed during the process. The region between the upper electrode assembly 110 and the lower electrode assembly 120 is a processing region where high-frequency energy is generated to excite and sustain the plasma. Process gas is introduced into reaction chamber 100 through the spray head of upper electrode assembly 110. One or more radio frequency power supplies can be applied individually to lower electrode assembly 120 or applied separately to upper electrode assembly 110 and lower electrode assembly 120, thereby generating a large electric field inside reaction chamber 100. Figure 1 In the embodiment shown, the radio frequency signal output by the radio frequency power supply 150 is applied to the mounting plate 126 via the matching circuit 152 and a hollow main radio frequency conduction rod 154.

[0037] Most of the electric field is contained within the processing region between the upper electrode assembly 110 and the lower electrode assembly 120. This electric field accelerates a small number of electrons present inside the reaction chamber, causing them to collide with gas molecules of the input reactive gas. These collisions lead to ionization of the reactive gas and excitation of plasma, thereby generating plasma within the reaction chamber 100. Neutral gas molecules of the reactive gas lose electrons when subjected to these strong electric fields, leaving behind positively charged ions. These positively charged ions are accelerated towards the lower electrode assembly 120, combining with neutral materials in the wafer being processed, thus stimulating wafer processing, such as etching and deposition.

[0038] An exhaust zone is provided at a suitable location in the plasma processing device. The exhaust zone is connected to an external exhaust device (not shown in the figure) to extract the used reaction gas and by-product gas from the processing zone during the processing, and to establish an appropriate pressure in the processing zone through gas flow.

[0039] Figure 2The diagram shows an enlarged view of the edge region of the lower electrode assembly. At least one edge ring is typically positioned around the lower electrode assembly 120 to adjust parameters such as the electric field distribution or temperature in the edge region. One edge ring exposed to the plasma processing area is a focus ring 130, and a coupling ring 133 is positioned below the focus ring. The focus ring 130 is typically made of insulating materials such as quartz or alumina, or semiconductor materials such as silicon carbide or silicon, to prevent particle contamination of the substrate during plasma processing and to provide sufficient conductivity. However, with repeated plasma processing, the erosion of the focus ring caused by ion bombardment deepens, reducing the ring's thickness and causing a change in the height of the plasma sheath above the focus ring. This results in a change in the ion orientation in the wafer edge region. Consequently, the etched pattern in the wafer edge region cannot be formed perpendicularly, resulting in titling.

[0040] The present invention provides an edge adjustment mechanism below the focusing ring, specifically including: a radio frequency distribution ring 180 below the focusing ring, the radio frequency distribution ring 180 being connected to an edge radio frequency transmission line 140, the edge radio frequency transmission line 140 introducing a radio frequency signal through an impedance adjustment module 160 and applying it to the radio frequency distribution ring 180, the radio frequency signal being coupled to the focusing ring through the radio frequency distribution ring, for adjusting the edge electric field and plasma distribution in the edge region.

[0041] exist Figure 1 In the illustrated embodiment, the impedance adjustment module 160 includes several fixed capacitors 162 connected in parallel and a high-voltage resistant vacuum relay 164 matched with the fixed capacitors. The vacuum relay controls the switching of the fixed capacitors via a power supply to determine the capacitance value connected to the impedance adjustment module. This impedance adjustment module 160 can withstand high radio frequency voltages; for example, when the radio frequency power output by the power supply exceeds 20 kW, the impedance adjustment module can still ensure stable operation. Due to the large size of the high-voltage resistant vacuum relay, the impedance adjustment module 160 is placed in the atmospheric environment below the mounting plate 126. In this invention, the edge radio frequency transmission line 140 includes a transmission line 142 located in the atmospheric environment and a transmission line 141 located in the vacuum environment. Because the edge adjustment mechanism of this invention has the characteristic of being resistant to high radio frequency voltages, the transmission line 141 located in the vacuum environment also has the characteristic of being resistant to high voltages.

[0042] To ensure that the transmission line 141 in the vacuum environment can withstand high voltage, a dielectric sleeve 145 is fitted over the portion of the edge radio frequency transmission line located inside the vacuum reaction chamber to achieve electrical isolation between the edge radio frequency transmission line and the lower electrode assembly. The dielectric sleeve 145 can be a high-purity ceramic sleeve with a purity greater than 95%. In other embodiments, the dielectric sleeve 145 can also be made of other insulating materials. Due to mechanical errors and considerations such as thermal expansion and assembly, a gap may be left between the transmission line 141 in the vacuum environment and the dielectric sleeve 145. To avoid possible ignition between these gaps, the distance between the inner diameter of the dielectric sleeve and the edge radio frequency transmission line is less than or equal to 0.3 mm. In some embodiments, for ease of installation, the edge radio frequency transmission line can be configured as several segments, and the dielectric sleeve includes several ceramic isolators. A groove assembly is provided on the mating surface between two adjacent ceramic isolators to increase the creepage distance and prevent breakdown.

[0043] A portion of the low-frequency radio frequency (RF) signal output from the matching circuit 152 is applied to the lower electrode assembly via the main RF transmission rod 154, while another portion is supplied to the RF distribution loop 180 via the edge RF transmission line 140 and impedance adjustment module 160. At least a portion of the edge RF transmission line output from the impedance adjustment module is located inside the hollow structure of the main RF transmission rod. Placing the edge RF transmission line 140 inside the hollow main RF transmission rod helps ensure the symmetry of high-frequency RF power transmission in the circumferential direction. Due to the high-frequency skin effect, the high-frequency RF current is distributed outside the main RF transmission rod. Placing the edge transmission line inside the hollow main RF transmission rod helps minimize the impact on the high-frequency RF transmission loop. Furthermore, since the impedance adjustment module 160 is located outside the vacuum reaction chamber and far from the focusing ring, placing the edge RF transmission line leading out from the impedance adjustment module 160 inside the hollow main RF transmission rod 154 allows for a shorter edge RF transmission line length, simplifying the wiring below the mounting plate 126.

[0044] The edge radio frequency transmission line 142 located in the atmospheric environment can be a continuous conductor, while the transmission line 141 located in the vacuum environment can be configured as several conductive rods due to installation requirements. These conductive rods are electrically connected, and each conductive rod is externally fitted with a dielectric sleeve to achieve electrical isolation from the lower electrode assembly. In this embodiment, the radio frequency signal output from the transmission line 142 located in the atmospheric environment can be applied to different positions of the radio frequency distribution ring through several conductive rods. The distribution of the multiple conductive rods can be uniform or non-uniform to improve the uniformity of the radio frequency distribution or to be adjusted to non-uniform at different phase angles. In another embodiment, the radio frequency signal output from the transmission line 142 located in the atmospheric environment can also be applied to the radio frequency distribution ring through only one conductive rod; the specific choice can be made according to actual needs.

[0045] The transmission line 141 located in a vacuum environment can be as follows Figure 2 The through mounting plate 126 and conductive base 122 shown are applied upward to the radio frequency distribution ring 180, or they can be located inside the isolation ring 134 surrounding the lower electrode assembly, or between the outer periphery of the lower electrode assembly and the isolation ring 134.

[0046] exist Figure 2 In the illustrated embodiment, the radio frequency (RF) power supply 150 includes a high-frequency power supply 1510 and a low-frequency power supply 1520. The high-frequency power supply 1510 applies a high-frequency RF signal to the lower electrode assembly 120 via a high-frequency matching circuit 1512, primarily used to excite the process gas into plasma and control the plasma density. The low-frequency power supply 1520 applies a low-frequency RF signal to the lower electrode assembly 120 via a low-frequency matching circuit 1522, primarily used to control the thickness of the plasma sheath layer on the substrate surface. Figure 2 In the illustrated embodiment, the low-frequency radio frequency signal applied to the focusing ring and the low-frequency radio frequency signal applied to the lower electrode assembly 120 share the same radio frequency power supply 1520. In another embodiment, a separate edge radio frequency power supply can also be provided to apply the radio frequency signal to the focusing ring 130. Optionally, the second frequency, i.e., the output frequency of the low-frequency radio frequency power supply 1520, is less than or equal to 2MHz. Optionally, the second frequency, i.e., the output frequency of the low-frequency radio frequency power supply, is less than or equal to 1MHz.

[0047] The inventors discovered that when high-frequency radio frequency (RF) power is applied to the lower electrode assembly 120, the RF power can be easily coupled to the focusing ring because the very thin (tens of micrometers) insulating and corrosion-resistant layer on the surface of the lower electrode assembly 120 and the coupling ring 133 have very low impedance for high-frequency signals. However, for low-frequency RF signals, the lower frequency causes the same insulating layer and coupling ring 133 to form a large impedance. This impedance results in only a small amount of low-frequency RF energy being coupled to the focusing ring 130. Even with various methods to adjust the dielectric constant and position of the coupling ring and the focusing ring, the ultimately adjustable range remains limited. Because the insulating and corrosion-resistant layer on the sidewall of the conductive substrate 122 is essential, and the coupling ring is usually made of insulating materials such as alumina or silicon oxide, it is impossible to adjustably distribute low-frequency RF power to the focusing ring 130 at the edge of the substrate under the existing hardware structure. The coupling ring can also be made of a highly conductive material, but this type of coupling ring can only achieve a good etching effect for a short time, and over time it still cannot compensate for the processing effect drift caused by the loss of the focusing ring. Moreover, the highly conductive coupling ring not only affects the distribution of low-frequency radio frequency power but also the distribution of high-frequency radio frequency power, which in turn affects the distribution of plasma concentration. Therefore, adjusting the thickness of the sheath above the focusing ring can actually cause uneven plasma concentration distribution and fail to improve the overall plasma treatment effect.

[0048] This invention employs an edge adjustment mechanism to actively apply low-frequency radio frequency (RF) signals that are difficult to couple to the edge region to the area below the focusing ring. An impedance adjustment module 160 is connected to actively adjust the circuit impedance. The low-frequency RF power delivered to the focusing ring is adjusted by selecting the capacitance values ​​of fixed capacitors 162 at different levels. The impedance adjustment module, located in the atmospheric environment below the lower electrode assembly 120, includes several levels of fixed capacitors and a high-voltage-resistant vacuum relay. It can withstand the high voltage output of the RF power supply to meet the increasingly demanding requirements of high aspect ratio etching processes. The edge adjustment mechanism in this embodiment can withstand RF environments with output power greater than or equal to 10 kW and output voltage greater than or equal to 8 kW. To prevent high-frequency radio frequency signals from entering the edge radio frequency transmission line 140 and causing problems such as overheating of the edge radio frequency transmission line 140, a radio frequency filter, namely a filter inductor 170, can be set on the edge radio frequency transmission line 140. Optionally, the range of the filter inductor can be 0-10 microhenries. The filter inductor can prevent high-frequency radio frequency signals in the vacuum reaction chamber from being transmitted downwards to the edge radio frequency transmission line 140 and burning out the edge radio frequency transmission line 140.

[0049] Figure 3A and Figure 3B Schematic diagrams of two different embodiments of the contact interface between the RF distribution ring and the focusing ring are shown. Figure 3A In the illustrated embodiment, the focusing ring is positioned above the RF distribution ring 180. Since the focusing ring is typically made of insulating materials such as quartz or alumina, or semiconductor materials such as silicon carbide or silicon, and the RF distribution ring is typically made of conductive materials such as aluminum or aluminum alloy, or semiconductor materials, both have a certain degree of rigidity. Therefore, to avoid inconsistent distances between different contact areas leading to uneven RF distribution when the two are in contact, an insulating coating 183 is provided on the surface of the RF distribution ring 180. For example, when the RF distribution ring 180 is made of aluminum or aluminum alloy, the insulating coating 186 can be alumina, so as to form a capacitor between the RF distribution ring 180 and the focusing ring 130, ensuring that the capacitance between different contact areas of the focusing ring and the RF distribution ring is consistent, thereby forming a sheath layer of the same height on the surface of the focusing ring at different phase angles.

[0050] exist Figure 3BIn the illustrated embodiment, a cover ring 132 is provided on the outer edge of the focusing ring 130. The cover ring 132 is mechanically locked to the coupling ring below, thus ensuring good electrical contact between the bottom surface of the focusing ring and the RF distribution ring. A graphite layer 182 is then provided above the RF distribution ring. A layer of metal material 184, such as aluminum or an aluminum alloy, may be embedded inside the graphite layer 182 to maintain its mechanical strength. The graphite layer has good conductivity and a certain degree of flexibility, ensuring that the RF signal from the RF distribution ring 180 is uniformly applied to the focusing ring throughout the entire annular area. This ensures uniform RF signal distribution at all angles while improving the efficiency of RF signal transmission.

[0051] Figure 4 A schematic diagram of an inductively coupled plasma processing device is shown. Figure 4 The plasma processing device shown has a reaction chamber 200, and... Figure 1 Unlike the capacitively coupled plasma reaction chamber 100, the ICP etching equipment is a device that uses an inductor coil to couple energy from a radio frequency power supply into the reaction chamber via a magnetic field, thereby generating plasma for etching. The inductively coupled plasma reaction device includes a vacuum reaction chamber 200, which has a generally cylindrical sidewall made of metal. An insulating window 210 is positioned above the sidewall, and an inductively coupled coil 212 is positioned above the window 210. The inductively coupled coil 140 is connected to the radio frequency power supply 2510 via a matching circuit 2512.

[0052] A gas injection port 214 is provided at one end of the sidewall of the reaction chamber near the insulating window 210. In some devices, a gas injection port is also provided in the central region of the insulating window 210. The reaction gas enters the vacuum reaction chamber 200 through the gas injection port 214. The radio frequency power of the radio frequency power supply 2510 drives the inductively coupled coil 212 to generate a strong high-frequency alternating magnetic field, causing the low-pressure reaction gas to be ionized and generate plasma. A lower electrode assembly 220 is provided downstream of the vacuum reaction chamber 200. The lower electrode assembly 220 has a... Figure 1 The lower electrode assembly 120 in the capacitively coupled plasma processing apparatus shown has an approximate structure including a conductive base 222, an electrostatic adsorption layer 224 above the conductive base, and a mounting plate 226 below the conductive base. The electrostatic adsorption layer is used to support and adsorb the wafer W to be processed during the process. The plasma contains a large number of active particles such as electrons, ions, excited-state atoms, molecules, and free radicals. These active particles can undergo various physical and chemical reactions with the surface of the substrate to be processed, thereby changing the morphology of the substrate surface, i.e., completing the etching process.

[0053] In this embodiment, the RF power supply 2520 applied to the lower electrode assembly is a bias RF power supply, typically with a frequency lower than that of the RF power supply 2510. The low-frequency RF signal output from the RF power supply 2520 is applied to the mounting plate 226 via a matching circuit 2522 and a hollow RF conductive rod 254 to control the sheath distribution on the wafer surface. Simultaneously, as described above, the invention also includes an edge adjustment mechanism to actively apply low-frequency RF signals that are difficult to couple to the edge region below the focusing ring 230. An impedance adjustment module 260 is connected to achieve active adjustment of the circuit impedance. Optionally, the impedance adjustment module 260 in this embodiment includes a motor capacitor for impedance adjustment of the low-frequency RF signal applied to the focusing ring. The motor capacitor can withstand high voltages and can achieve continuous adjustment between 0-100%, providing high adjustment accuracy. It is easily understood that the impedance adjustment module 260 in this embodiment can also be applied to... Figure 1 Similarly, in the capacitively coupled plasma processing device shown, Figure 1 The impedance adjustment module 160 in this embodiment can also be used in the inductively coupled plasma processing device.

[0054] Similar to the embodiments described above, the edge radio frequency transmission line 240 includes a transmission line 241 located in a vacuum environment and a transmission line 242 located in an atmospheric environment. The requirements for setting up the edge radio frequency transmission line and the settings for radio frequency distribution rings are the same as described above, and will not be repeated here.

[0055] This invention also discloses a plasma treatment method with edge impedance adjustment function, the method in Figure 1 or Figure 4 The process is carried out within any of the plasma processing devices, and the method includes the following steps:

[0056] Substrate etching effect monitoring steps: Detect the etching effect in the edge area of ​​the substrate. If the tilt angle of the etching hole at the edge of the substrate is within the preset angle range, continue to execute the substrate etching effect detection step. If the tilt angle of the etching hole at the edge of the substrate exceeds the preset threshold, proceed to the variable impedance adjustment step.

[0057] Variable impedance adjustment step: Adjust the capacitance value of the high voltage adjustable capacitor component to change the impedance of the impedance adjustment module, thereby changing the RF power delivered to the substrate edge ring, and then re-enter the substrate etching effect monitoring step.

[0058] The adjustable capacitor in the impedance adjustment module described in this invention is an optional embodiment. However, any other variable impedance device that can switch to low-frequency RF power impedance, such as a hybrid circuit consisting of variable inductors and capacitors or a circuit composed of other components, can achieve the impedance adjustment function. The above substitutions are common knowledge, so they will not be listed one by one.

[0059] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A plasma processing device, characterized in that: include: A vacuum reaction chamber, wherein a lower electrode assembly is disposed within the vacuum reaction chamber, the lower electrode assembly including a conductive base; A main radio frequency transmission rod is electrically connected to at least one radio frequency power supply for applying a first radio frequency signal to the conductive base, and the main radio frequency transmission rod includes a hollow structure. An edge ring is disposed around the lower electrode assembly; a radio frequency distribution ring is disposed below the edge ring, the surface of the radio frequency distribution ring is provided with an insulating coating or a graphite coating; the radio frequency distribution ring is conductive, including a conductor material or a semiconductor material; An impedance adjustment module, located in the atmospheric environment below the conductive base, includes at least one high-voltage adjustable capacitor assembly. An edge radio frequency transmission line is electrically connected to the radio frequency distribution ring through the impedance adjustment module to apply a second radio frequency signal to the edge ring. The edge radio frequency transmission line in the vacuum environment is covered with a dielectric sleeve, and the edge radio frequency transmission line in the atmospheric environment is at least partially located inside the hollow structure of the main radio frequency transmission rod.

2. The plasma processing apparatus as described in claim 1, characterized in that: The edge radio frequency transmission line includes multiple conductive rods, which are electrically connected to the radio frequency distribution ring uniformly or non-uniformly.

3. The plasma processing apparatus according to any one of claims 1-2, characterized in that: The impedance adjustment module includes multiple fixed capacitors connected in parallel, and each fixed capacitor is equipped with a high-voltage resistant vacuum relay.

4. The plasma processing apparatus according to any one of claims 1-2, characterized in that: The impedance adjustment module includes a motor capacitor.

5. The plasma processing apparatus according to any one of claims 1-2, characterized in that: The radio frequency power supply includes a radio frequency power supply with a first frequency and a radio frequency power supply with a second frequency.

6. The plasma processing apparatus as described in claim 5, characterized in that: The second radio frequency signal has a second frequency.

7. The plasma processing apparatus as described in claim 6, characterized in that: An RF filter is provided between the main RF transmission rod and the edge RF transmission line, and the RF filter is used to filter the RF signal of the first frequency.

8. The plasma processing apparatus as described in claim 6, characterized in that: The output voltage of the second frequency radio frequency power supply is greater than or equal to 8KV.

9. The plasma processing apparatus as described in claim 6, characterized in that: The output power of the second frequency radio frequency power supply is greater than or equal to 10KW.

10. The plasma processing apparatus as described in claim 6, characterized in that: The second frequency is less than the first frequency.

11. The plasma processing apparatus as described in claim 6, characterized in that: The second frequency is less than or equal to 2MHz.

12. The plasma processing apparatus as described in claim 6, characterized in that: The second frequency is less than or equal to 1 MHz.

13. The plasma processing apparatus as claimed in claim 1, characterized in that: A mounting plate is disposed below the conductive base, and the main radio frequency transmission rod is electrically connected to the mounting plate.

14. The plasma processing apparatus as claimed in claim 1, characterized in that: The dielectric sleeve is made of high-purity ceramic, with a purity greater than 95%.

15. The plasma processing apparatus as claimed in claim 1, characterized in that: The distance between the inner diameter of the dielectric sleeve and the edge radio frequency transmission line is less than or equal to 0.3 mm.

16. The plasma processing apparatus as claimed in claim 1, characterized in that: The dielectric sleeve includes several ceramic insulating components, and a groove assembly is provided on the mating surface between two adjacent ceramic insulating components to prevent breakdown.

17. The plasma processing apparatus as claimed in claim 1, characterized in that: The edge ring is a focusing ring.

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