Plasma processing device and lower electrode assembly thereof

Abstract

The invention provides a plasma processing device and a lower electrode assembly thereof. The plasma processing device comprises a reaction cavity; the base is arranged in the reaction cavity and is used for bearing a substrate; the restraint ring is arranged around the periphery of the base, is positioned between the base and the cavity body of the reaction cavity and is used for restraining plasmas generated in the reaction cavity; and the capacitor is arranged between the restraint ring and the cavity body of the reaction cavity. According to the invention, the capacitance value between the restraint ring and the cavity can be accurately controlled, the arc discharge phenomenon is avoided, the restraint ring is effectively protected, and the working safety and stability of the lower electrode assembly and the plasma processing device are ensured.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and in particular to a plasma processing apparatus and its lower electrode assembly. Background Technology

[0002] Plasma treatment processes on semiconductor substrates, such as etching or deposition, are performed within the reaction chamber of a plasma treatment apparatus; for example... Figure 1 As shown, the substrate W is supported by a base 102' at the bottom of the reaction chamber. The process gas injected into the reaction chamber is excited by the radio frequency energy coupled into the chamber, forming plasma above the substrate W to process the substrate W. A confinement ring 30' is provided around the base 102' to confine the plasma. The confinement ring 30' is located on the exhaust path between the base 102' and the reaction chamber body 100'. When the plasma passes through the confinement ring 30' along with the reaction byproducts to be discharged, it becomes electrically neutral, preventing plasma from leaking below the confinement ring 30' and damaging the device. Figure 1 The device board 104', focusing ring 105', edge ring 106', grounding ring 108', first isolation ring 107', and second isolation ring 109' are also shown.

[0003] A DC-insulating insulating protective layer is formed on the surface of the constraint ring 30' that is opposite to or in contact with the cavity 100' of the reaction chamber. This allows for AC grounding of the constraint ring 30' by forming a large capacitance between it and the grounded cavity 100'. When forming the aforementioned insulating protective layer through surface oxidation, coating, or other methods, it is easily affected by factors such as process technology and component quality, resulting in unstable capacitance values. Problems such as poor surface flatness, tolerances in component gaps, uneven protective layer thickness, or peeling can all cause fluctuations in the capacitance value between the constraint ring and the cavity, affecting the safety and stability of the lower electrode assembly and the substrate processing effect.

[0004] If the capacitance between the confinement ring 30' and the cavity 100' is too large, the confinement ring 30' will have a good grounding effect, but a thicker plasma sheath layer will form above the confinement ring 30', generating strong plasma bombardment, damaging the plasma corrosion-resistant coating on the upper surface of the confinement ring (see P1), and reducing the lifespan of the device. If the capacitance between the confinement ring 30' and the cavity 100' is too small, there will be a large voltage difference between them, which can easily lead to arc discharge, breaking down the insulating protective layer of the confinement ring (see P2), causing RF energy leakage, failure of plasma confinement, and other problems.

[0005] With the increasing demand for high aspect ratio etching in semiconductor manufacturing, the use of high radio frequency (RF) power is becoming more and more common. Increased RF power results in higher plasma density and energy, leading to greater damage to the plasma-resistant coating when it bombards the confinement ring. Furthermore, increased RF power also raises the voltage on the confinement ring, increasing the risk of arcing between the confinement ring and the cavity, and the risk of insulation breakdown due to arcing. Summary of the Invention

[0006] This invention provides a plasma processing device and its lower electrode assembly. A capacitor is installed between the constraint ring of the lower electrode assembly and the cavity of the reaction chamber to accurately control the capacitance value between the constraint ring and the cavity, reduce the occurrence of arc discharge, effectively protect the constraint ring, and ensure the safe and stable operation of the lower electrode assembly.

[0007] One object of the present invention is to provide a lower electrode assembly for a plasma processing device, the plasma processing device including a reaction chamber; a base disposed within the reaction chamber for supporting a substrate; a constraint ring disposed around the periphery of the base and located between the base and the cavity of the reaction chamber for constraining the plasma generated within the reaction chamber; and a capacitor disposed between the constraint ring and the cavity of the reaction chamber.

[0008] Optionally, a receiving space is provided between the constraint ring and the cavity of the reaction chamber, and the receiving space is used to place the capacitor.

[0009] Optionally, the accommodating space is formed at the constraint ring, or at the cavity of the reaction chamber, or in combination at the cavity of both the constraint ring and the reaction chamber.

[0010] Optionally, the receiving space is a groove or a recess.

[0011] Optionally, the constraint ring includes an exhaust portion with an exhaust channel and a support portion surrounding the exhaust portion; a step is formed in the cavity of the reaction chamber to support the support portion of the constraint ring.

[0012] Optionally, when the receiving space is formed in the support portion of the constraint ring, the opening of the receiving space faces the inner wall of the reaction chamber, or faces the stepped surface of the chamber, or faces both the inner wall and the stepped surface of the chamber simultaneously.

[0013] When the receiving space is formed on the inner wall of the cavity, the opening of the receiving space faces the constraint ring;

[0014] When the receiving space is formed on the stepped surface of the cavity, the opening of the receiving space faces the support of the constraint ring.

[0015] Optionally, the support portion of the constraint ring is provided with an annular groove for placing one or more of the capacitors.

[0016] Optionally, the capacitor has a fixed capacitance value or an adjustable capacitance value.

[0017] Optionally, the capacitor may comprise a plurality of capacitor elements connected in series or a plurality of capacitor elements connected in parallel.

[0018] Optionally, a plurality of capacitors are provided between the constraint ring and the cavity of the reaction chamber, and the plurality of capacitors are evenly distributed along the circumferential direction of the constraint ring.

[0019] Optionally, the upper surface of the constraint ring is provided with a protective layer resistant to plasma corrosion.

[0020] Optionally, the surface of the constraint ring that contacts the cavity of the reaction chamber is insulated.

[0021] Another object of the present invention is to provide a plasma processing apparatus comprising:

[0022] A reaction chamber connected to a gas supply device; the reaction chamber is equipped with any of the aforementioned lower electrode assemblies.

[0023] The gas introduced into the reaction chamber is excited by radio frequency energy coupled into the reaction chamber to form plasma, which is used to process the substrate placed on the base at the bottom of the reaction chamber; an exhaust pump connected to the reaction chamber is used to discharge the reaction byproducts from the reaction chamber.

[0024] A constraint ring is arranged around the periphery of the base and located between the base and the cavity of the reaction chamber, for constraining the plasma generated within the reaction chamber;

[0025] A capacitor is disposed between the constraint ring and the cavity of the reaction chamber; the capacitance value between the constraint ring and the cavity is obtained by connecting the device capacitance between the constraint ring and the cavity and the capacitance of the capacitor in parallel.

[0026] Optionally, the capacitance between the constraint ring and the cavity can be changed by adjusting the capacitance value of the current capacitor or by replacing it with another capacitor that has a different capacitance value.

[0027] Optionally, the source radio frequency power used to provide radio frequency energy to generate plasma is 35kW to 50kW.

[0028] Optionally, the plasma processing apparatus further comprises:

[0029] An electrostatic chuck, mounted on top of the base, is used to secure the substrate.

[0030] The focusing ring and edge ring surrounding the electrostatic chuck are used to adjust the electric field or temperature distribution around the substrate;

[0031] A grounding ring surrounding the base is used to form a radio frequency grounding loop;

[0032] An isolation ring located between the grounding ring and the base provides electrical isolation between the base and the grounding ring.

[0033] The plasma processing device and its lower electrode assembly provided by the present invention have the following advantages:

[0034] This invention places a capacitor between the constraint ring and the cavity of the reaction chamber, connecting the device capacitance and the capacitor capacitance in parallel to obtain the capacitance value between the constraint ring and the cavity. By replacing capacitors with different capacitance values ​​or setting an adjustable capacitor, the capacitance can be easily controlled and adjusted, thereby configuring a suitable capacitance value between the constraint ring and the cavity to adapt to various process technologies or different component configurations. The actual values ​​of the device capacitance before capacitor installation and the capacitance value between the constraint ring and the cavity after capacitor installation can be measured, allowing for quick assessment of whether the capacitance value between the constraint ring and the cavity meets design requirements after capacitor installation.

[0035] Therefore, the present invention can accurately control and adjust the capacitance value between the constraint ring and the cavity, making the capacitance value more stable, the AC grounding of the constraint ring more reliable, effectively avoiding arc discharge and insulation breakdown between the constraint ring and the cavity, effectively protecting the constraint ring, and ensuring the safe and reliable operation of the lower electrode assembly and plasma processing device. Attached Figure Description

[0036] Figure 1 This is a partial structural diagram of a lower electrode assembly;

[0037] Figure 2 This is a schematic diagram of an inductively coupled plasma processing device according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the capacitively coupled plasma processing device shown in an embodiment of the present invention;

[0039] Figures 4-9 This is a bottom view of the constraint ring shown in an embodiment of the present invention;

[0040] Figure 4 The bottom surface of the support part of the constraint ring is provided with an annular groove and a capacitor is installed therein;

[0041] Figure 5 The constraint ring has an annular groove on the bottom surface of the support and multiple capacitors are installed.

[0042] Figure 6 The constraint ring has annular grooves on the bottom and sides of the support part, and multiple capacitors are installed therein;

[0043] Figure 7 The constraint ring has grooves on the bottom and sides of the support part, and capacitors are installed accordingly.

[0044] Figure 8 The constraint ring has a recessed hole on the bottom surface of the support part, and a capacitor is correspondingly installed thereon;

[0045] Figure 9 The constraint ring has recessed holes on the bottom and sides of the support part, and some of the recessed holes are equipped with capacitors;

[0046] Figures 10-11 This is a schematic diagram illustrating the different forms of accommodating space provided by the constraint ring and cavity in the embodiments;

[0047] Figure 10 The constraint ring is provided with an annular groove, and the cavity is provided with multiple concave holes;

[0048] Figure 11 The cavity is provided with an annular groove, and the constraint ring is provided with multiple groove segments.

[0049] Figures 12-19 This is a partial structural schematic diagram of the lower electrode assembly shown in an embodiment of the present invention;

[0050] Figure 12 The accommodating space is located in the constraint ring, with the opening facing the inner wall and step of the cavity;

[0051] Figure 13 The accommodating space is located in the constraint ring, with the opening facing the step of the cavity;

[0052] Figure 14 The accommodating space is located in the constraint ring, with the opening facing the inner wall of the cavity;

[0053] Figure 15 The accommodating space is located in the cavity, with the opening facing the side of the constraint ring;

[0054] Figure 16 The accommodating space is located in the cavity, with the opening facing the lower surface of the constraint ring;

[0055] Figure 17 The accommodating space is located on the inner wall of the cavity and the side of the constraint ring;

[0056] Figure 18 The accommodating space is located on the lower surface of the cavity steps and the constraint ring;

[0057] Figure 19 The accommodating space is provided on multiple opposing surfaces of the cavity and the constraint ring. Detailed Implementation

[0058] The embodiments of the present invention will be described below with reference to the accompanying drawings. The relevant content is for illustrative purposes only and is not intended to limit the constraint ring, lower electrode assembly or applicable plasma processing apparatus of the present invention.

[0059] like Figure 2 , Figure 3 As shown, the plasma processing apparatus of this embodiment includes a vacuum-ejectable reaction chamber, which has a generally cylindrical cavity 100 made of metal material; a gas supply device 500 connected to the reaction chamber, which can introduce process gas, auxiliary gas, etc. into the reaction chamber; radio frequency energy is coupled into the reaction chamber by inductors and / or capacitors to excite the process gas to form and maintain plasma for etching, deposition and other corresponding process treatments on the substrate W; a lower electrode assembly is provided inside the reaction chamber to support the substrate W and control factors affecting substrate processing such as substrate temperature and electric field; an exhaust pump 600 is connected to the bottom of the reaction chamber to discharge reaction byproducts and other gases from the reaction chamber to maintain a vacuum environment inside the chamber.

[0060] exist Figure 2 In one type of inductively coupled plasma processing device, an insulating window 201 is provided above the cavity 100 of the reaction chamber. Source radio frequency power 203 is applied to the inductor coil 202 above the insulating window 201 through a matching network 204, inducing an alternating electric field within the reaction chamber to achieve plasma dissociation of the process gas. In different examples, the process gas and auxiliary gas can be discharged through an opening on the side of the cavity 100 (see...). Figure 2 ), and / or conveyed into the reaction chamber from the opening (not shown) at the insulating window 201. Figure 3 In the capacitively coupled plasma processing device shown, an upper electrode assembly is further provided in the reaction chamber; the upper electrode assembly includes a gas spray head 701, which is connected to a gas supply device 500 and is used to transport process gas, auxiliary gas, etc. into the reaction chamber; the gas spray head 701 is arranged opposite to the base 102, and the two serve as the upper electrode and the lower electrode respectively; the source radio frequency power 702 is applied to the upper electrode and / or the lower electrode through a matching network 703 to form a radio frequency electric field, thereby realizing the plasma dissociation of the process gas.

[0061] One example of a plasma processing apparatus is a device capable of generating plasma with higher energy and density under high radio frequency (RF) power conditions, thereby achieving higher sheath voltage and high aspect ratio etching of a substrate; wherein the source RF power providing the RF energy to generate the plasma is 35kW to 50kW. The above is an example and is not intended to limit the RF power of the plasma processing apparatus.

[0062] See also Figure 2 , Figure 3 , Figure 4In the example of the lower electrode assembly, the substrate W is supported by a base 102 located at the bottom of the reaction chamber. An electrostatic chuck 101 is located at the top of the base 102, and a DC electrode 103 is located within the electrostatic chuck 101, which can generate electrostatic adsorption to fix the substrate W. An equipment plate 104 at the bottom of the base 102 can accommodate various power supply and heating equipment required for the lower electrode assembly. A focusing ring 105 and an edge ring 106 are provided around the electrostatic chuck 101 to adjust the electric field or temperature distribution around the substrate, improving the uniformity of substrate processing. A grounding ring 108 surrounding the base 102 forms an RF grounding loop; a first isolation ring 107 and a second isolation ring 109 are provided between the grounding ring 108 and the base 102 to achieve electrical isolation between them. Bias RF power 205 can be applied to the base 102 through a matching network 206 (see...). Figure 2 (), used to control the bombardment direction of charged particles in plasma.

[0063] A confinement ring 300 is arranged around the periphery of the base 102 to confine the plasma generated within the reaction chamber. The confinement ring 300 is located on the exhaust path between the base 102 and the cavity 100 of the reaction chamber. The plasma, along with reaction byproducts, passes through the exhaust channel 301 of the confinement ring 300 (see...). Figure 12 When the plasma is extinguished, the charged particles in the plasma are extinguished, becoming neutral gas that flows downwards, preventing plasma leakage below the confinement ring 300. The example confinement ring 300 is made of a metallic material and has a corrosion-resistant protective layer formed on its surface to prevent corrosion by the plasma. For example, an anodic oxide layer is formed on the entire surface of the confinement ring 300 (e.g., an anodic aluminum oxide layer is formed on the surface of an aluminum confinement ring 300), and at least the upper surface of the confinement ring 300 is coated with a yttrium oxide coating. An insulating protective layer is provided on the surface of the confinement ring 300 opposite to the reaction chamber 100, providing DC insulation between the confinement ring 300 and the chamber 100; such as the anodic oxide layer on the surface of the confinement ring 300, it can be used as the insulating protective layer, but the formation of the insulating protective layer is not limited to this. The constraint ring 300 can directly contact the cavity 100 through the insulating protective layer; alternatively, a gasket is provided between the insulating protective layer of the constraint ring 300 and the cavity 100 to control or adjust the gap between the constraint ring 300 and the cavity 100, making slight adjustments to the capacitance value between them. Using a conductive sheet (such as an aluminum sheet) as the gasket can ensure good contact between the constraint ring 300 and the cavity 100.

[0064] To address the arc discharge problem between the constraint ring 300 and the cavity 100 of the reaction chamber, the lower electrode assembly described in this embodiment further includes a capacitor 400. The capacitor 400 is physically connected between the constraint ring 300 and the cavity 100 of the reaction chamber. The capacitance between the constraint ring 300 and the cavity 100 is obtained by connecting the capacitance of the capacitor 400 and the inherent device capacitance between the constraint ring 300 and the cavity 100 in parallel (the device capacitance can be formed based on the insulating protective layer of the constraint ring 300, the gap between the constraint ring 300 and the cavity 100, etc.). After setting the capacitor 400, the capacitance between the constraint ring 300 and the cavity 100 needs to be sufficiently large to achieve AC grounding of the constraint ring 300.

[0065] The present invention does not limit the specific arrangement and connection method of the capacitor 400 between the constraint ring 300 and the cavity 100. For example, the capacitor 400 may be provided at one or more locations between the constraint ring 300 and the cavity 100.

[0066] For example, a capacitor 400 is installed in only one place. Figure 2 , Figure 3 , Figure 4 The capacitor 400 includes a single capacitor element, or the capacitor 400 includes multiple capacitor elements connected in series and / or in parallel. For example, the capacitor 400 is distributed in multiple locations. Figures 5-11 Each location can have one capacitor element, or multiple capacitor elements connected in series and / or in parallel. For example, if the finished capacitor 400 does not have a suitable capacitance value, or if fine control and adjustment of the capacitance value at a certain location is required, or if the size or voltage withstand performance of the capacitor 400 is taken into consideration, multiple capacitor elements can be connected in series and / or in parallel at that location to obtain the required capacitor capacitance.

[0067] When capacitors 400 are distributed in multiple locations, they are connected in parallel with each other, and are also connected in parallel with the device capacitances between the constraint ring 300 and the cavity 100. For example, the capacitors 400 can be evenly distributed along the circumference of the constraint ring 300, and the capacitance values ​​of the capacitors 400 at each location can be the same; alternatively, in other examples, the capacitance values ​​of the capacitors 400 at each location can be set to different values ​​as needed.

[0068] For example, the capacitor 400 can be installed in a location that is not directly exposed to the plasma environment to avoid plasma corrosion and reduce the requirements for corrosion protection of the capacitor 400 surface. This also avoids the capacitor 400 setting affecting the original gas or temperature distribution in the reaction chamber, ensuring that the substrate W processing effect is not affected by the setting of the capacitor 400.

[0069] In some examples, capacitor 400 can be directly connected to the constraint ring 300 and the cavity 100 of the reaction chamber. For example, capacitor 400 can be positioned below the constraint ring 300. Figure 2 , Figure 3 ).

[0070] In some examples, a receiving space 304 can be formed between the constraint ring 300 and the cavity 100 of the reaction chamber, and the capacitor 400 can be disposed within the receiving space 304. The receiving space 304 can be formed at the constraint ring 300. Figures 4-9 , Figures 12-14 ), or formed at 100 points in the cavity ( Figure 15 , Figure 16 ), or formed in conjunction with the constraint ring 300 and the cavity 100 ( Figure 10 , Figure 11 , Figures 17-19 ).

[0071] When capacitors 400 are distributed in multiple locations, each can have its own corresponding housing space 304, and these housing spaces 304 are separated from each other. Figures 7-9 Alternatively, a connected, shared space can be used as the receiving space 304, and capacitors 400 can be arranged at multiple locations within the receiving space 304. Figure 5 , Figure 6 ).

[0072] When the receiving space 304 is formed in the constraint ring 300, the opening of the receiving space 304 may be disposed downwards, or towards the cavity 100 of the reaction chamber, or both downwards and towards the cavity 100 of the reaction chamber. When the receiving space 304 is formed in the cavity 100, the opening of the receiving space 304 may be disposed towards the circumferential side of the constraint ring 300. Alternatively, when a portion of the receiving space 304 is formed in the constraint ring 300 and another portion is formed in the cavity 100, the openings of the two portions are opposite to each other.

[0073] In some examples, the cavity 100 of the reaction chamber is provided with a step for supporting the constraint ring 300. The constraint ring 300 includes an exhaust portion 302 and a support portion 303 surrounding the exhaust portion 302. Figure 12 The exhaust section 302 has an exhaust channel 301 through which gases such as reaction byproducts can pass. The support section 303 is supported by a step at the cavity 100. If the accommodating space 304 is formed in the support section 303 of the constraint ring 300, the opening of the accommodating space 304 can face downwards. Figure 13 The opening is opposite to the stepped surface of the cavity 100; or, the opening may face the inner wall of the cavity 100. Figure 14 Alternatively, the opening can simultaneously face both the stepped surface and the inner wall of the cavity 100. Figure 12If the receiving space 304 is formed on the stepped surface of the cavity 100, the opening of the receiving space 304 can face upwards. Figure 16 The support portion 303 of the constraint ring 300 is opposite to the opening (the stepped surface next to the opening supports the constraint ring 300). For example, when forming the receiving space 304, the circumferential side of the support portion 303 of the constraint ring 300 forms an opening opposite to the inner wall of the cavity 100. Figure 17 Alternatively, the bottom surface of the support portion 303 of the constraint ring 300 and the stepped surface of the cavity 100 form a relative opening. Figure 18 , Figure 19 ).

[0074] The example receiving space 304 includes a groove. For example, the constraint ring 300 has an annular groove 305 in which a capacitor 400 is disposed. Figure 4 Alternatively, multiple capacitors 400 may be distributed within the annular groove 305. Figure 5 , Figure 6 For example, the groove on the constraint ring 300 does not encircle the constraint ring 300 circumferentially, but only includes one or more slot segments 306. Figure 7 The shape of the slot segment 306 is not limited, and it is used to set the capacitor 400; when the groove of the constraint ring 300 includes a plurality of mutually spaced slot segments 306, at least one of the slot segments 306 is provided with a capacitor 400 (e.g., each slot segment 306 is provided with a corresponding capacitor 400 (see...) Figure 7 Alternatively, capacitors 400 may be provided only in one or some of the slot segments 306, while capacitors 400 may not be provided in the other slot segments 306. The surface on which the annular slot 305 or slot segment 306 is formed at the constraint ring 300 may be the bottom surface of the support portion 303. Figure 4 , Figure 5 ) or circumferential side ( Figure 6 , Figure 7 ).

[0075] Alternatively, a similar annular groove 305 or groove segment 306 can be provided at the cavity 100 of the reaction chamber; the surface at the cavity 100 forming the annular groove 305 or groove segment 306 is, for example, the inner wall or stepped surface of the cavity 100. Alternatively, a groove can be formed on the opposing surfaces of the constraint ring 300 and the cavity 100 to form a similar annular groove 305 or groove segment 306 (for example, formed on the bottom surface of the support 303 and the stepped surface of the cavity 100, or on the circumferential side surface of the support 303 and the inner wall of the cavity 100).

[0076] The example receiving space 304 includes a recess 307. For example, the constraint ring 300 has a recess 307 (shape not limited) in which a capacitor 400 is disposed. As another example, the constraint ring 300 has multiple recesses 307 distributed throughout. Figure 8 , Figure 9 (The shape of the recess 307 is not limited), wherein at least one recess 307 is provided with a capacitor 400 (e.g., each recess 307 is provided with a corresponding capacitor 400). Figure 8 ), or only one or more recesses 307 contain capacitors 400 ( Figure 9 (Other recesses 307 may not have capacitors 400 installed). The surface on which the recess 307 is formed at the constraint ring 300 may be the bottom surface or the circumferential side surface of the support portion 303.

[0077] Alternatively, a similar recess 307 can be provided in the cavity 100 of the reaction chamber; the surface of the cavity 100 forming the recess 307 is, for example, the inner wall or stepped surface of the cavity 100. Alternatively, a similar recess 307 can be formed by fitting an opening on the opposing surface of the constraint ring 300 and the cavity 100 (for example, fitting on the bottom surface of the support 303 and the stepped surface of the cavity 100, or on the circumferential side surface of the support 303 and the inner wall of the cavity 100).

[0078] In some examples where the constraint ring 300 cooperates with the cavity 100 to form a receiving space 304, the constraint ring 300 may form an annular groove 305, and multiple recesses 307 may be formed on the cavity 100 at positions opposite to the annular groove 305, with a capacitor 400 disposed in at least one of the recesses 307. Figure 10 Alternatively, the constraint ring 300 may form a plurality of slot segments 306, and recesses 307 may be formed at multiple positions on the cavity 100 opposite to each slot segment 306, with a capacitor 400 (not shown) disposed in at least one of the recesses 307. In other examples, an annular groove 305 may be formed in the cavity 100, and recesses 307 or slot segments 306 may be formed at multiple positions on the constraint ring 300 opposite to the annular groove 305. Figure 11 Alternatively, a plurality of slot segments 306 may be formed in the cavity 100, and a plurality of slots 307 may be formed on the constraint ring 300 at a plurality of positions opposite to each slot segment 306, and a capacitor 400 may be provided in at least one of the slots 307 (not shown).

[0079] In the examples above, even if only one capacitor 400 needs to be installed, an annular groove 305 can still be provided around the entire circle on the constraint ring 300 or the cavity 100. Figure 4 The annular groove 305, groove segment 306, or recessed hole 307 are arranged in a uniform manner to make the stress or temperature distribution on the constraint ring 300 or cavity 100 more balanced.

[0080] For example, capacitor 400 has a fixed capacitance value; or capacitor 400 uses a variable capacitor whose capacitance value is adjustable within a set range.

[0081] For example, considering the current process and component configuration in the plasma processing device, a reference value a1 of the capacitance between the confinement ring 300 and the cavity 100 of the reaction chamber can be determined through simulation or experimentation. This reference value a1 is then set within a suitable threshold range A (assuming the lower limit of A is A1 and the upper limit is A2). The reference value a1 needs to be sufficiently large (a1 > A1) to meet the requirement of AC grounding of the confinement ring 300. This also reduces the voltage difference between the confinement ring 300 and the cavity 100, preventing arc discharge and arc breakdown of the insulating protective layer. At the same time, the reference value a1 needs to be not too large (a1 < A2) to reduce the thickness of the plasma sheath above the confinement ring 300, reduce the energy of ion bombardment, reduce damage to the corrosion-resistant protective layer on the upper surface of the confinement ring 300, and extend the service life of the confinement ring 300.

[0082] The capacitance between the constraint ring 300 and the cavity 100 of the reaction chamber can be measured using a testing tool to obtain the corresponding measured value b1, or an estimated value b2 can be determined based on simulation or experimentation. Based on the reference value a1 of the capacitance between the constraint ring 300 and the cavity 100, the measured value b1 or the estimated value b2 of the device capacitance, the calculated capacitance value c1 of the capacitor 400 can be calculated. Then, a capacitor 400 (which can be a single capacitor element or multiple capacitor elements connected in series and / or parallel) whose actual capacitance c2 matches the calculated capacitance value c1 is selected and installed between the constraint ring 300 and the cavity 100. After the capacitor 400 is installed, the actual capacitance value a2 between the constraint ring 300 and the cavity 100 can be measured again using a testing tool to ensure that the actual capacitance value a2 is within the aforementioned threshold range A (A1 < a2 < A2).

[0083] For example, the actual capacitance value a2 between the constraint ring 300 and the cavity 100 is compared with the previously determined reference value a1. If the two values ​​match, or the difference is within an acceptable range, then the actual capacitance value a2 is within the threshold range A, and the plasma processing apparatus with the installed capacitor 400 (capacitor capacitance c2 matches the calculated capacitance value c1) is suitable for the requirements of the current process. If the actual capacitance value a2 between the constraint ring 300 and the cavity 100 does not match the reference value a1, or the difference is too large, it indicates that the actual capacitance value a2 is not within the threshold range A. In this case, the capacitance value of the current capacitor 400 can be adjusted, or another capacitor 400 with a different capacitance value can be replaced. This adjusts the capacitance of the capacitor currently connected between the constraint ring 300 and the cavity 100 to c2' (the new capacitor capacitance c2' is connected in parallel with the device capacitance). After the capacitor capacitance adjustment, it is remeasured using a testing tool. The actual value of the capacitance, a2', is determined to be within the threshold range A (A1 < a2' < A2). If so, the plasma processing device, after installing the capacitor 400 with capacitance c2', can meet the requirements of the current process. Otherwise, the capacitor capacitance is further adjusted (the capacitance value of the current capacitor 400 is readjusted or a capacitor 400 with a different capacitance value is replaced), and the actual value of the capacitance is measured again and compared with the reference value in a similar manner until the actual value of the capacitance between the constraint ring 300 and the cavity 100 is within the threshold range A.

[0084] When different process flows are implemented, or when different components are configured in the lower electrode assembly or cavity 100 of the plasma processing device, the capacitance parameters applicable to the new process or device can be determined in the same way as described above. These parameters include, but are not limited to, the threshold range and reference value of the capacitance between the constraint ring 300 and the cavity 100, the measured or estimated value of the device capacitance, the calculated value of the capacitor capacitance, and the actual value of the capacitance between the constraint ring 300 and the cavity 100 after the capacitor 400 is installed. This allows for the determination of the appropriate capacitor 400 required for the current process in various plasma processing devices.

[0085] In summary, the plasma processing device and its lower electrode assembly provided by the present invention include a capacitor 400 disposed between the constraint ring 300 and the cavity 100 of the reaction chamber. This facilitates accurate control and adjustment of the capacitance value between the constraint ring 300 and the cavity 100, making the capacitance value more stable and the AC grounding of the constraint ring 300 more reliable. This effectively avoids arc discharge between the constraint ring 300 and the cavity 100, effectively protects the constraint ring 300, and ensures the safe and reliable operation of the lower electrode assembly and the plasma processing device.

[0086] 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 lower electrode assembly for a plasma processing apparatus, the plasma processing apparatus including a reaction chamber, characterized in that, A base, located within the reaction chamber, is used to support the substrate; A constraint ring is arranged around the periphery of the base and located between the base and the cavity of the reaction chamber, for constraining the plasma generated within the reaction chamber; A capacitor is disposed between the constraint ring and the cavity of the reaction chamber.

2. The lower electrode assembly as described in claim 1, characterized in that, A receiving space is provided between the constraint ring and the cavity of the reaction chamber, and the receiving space is used to place the capacitor.

3. The lower electrode assembly as described in claim 2, characterized in that, The accommodating space is formed at the constraint ring, or at the cavity of the reaction chamber, or in combination at the cavity of both the constraint ring and the reaction chamber.

4. The lower electrode assembly as described in claim 2, characterized in that, The accommodating space is a groove or a recess.

5. The lower electrode assembly as described in claim 2, characterized in that, The constraint ring includes an exhaust section with an exhaust channel and a support section surrounding the exhaust section; a step is formed in the cavity of the reaction chamber to support the support section of the constraint ring.

6. The lower electrode assembly as described in claim 5, characterized in that, When the accommodating space is formed in the support portion of the constraint ring, the opening of the accommodating space faces the inner wall of the reaction chamber, or faces the stepped surface of the chamber, or faces both the inner wall and the stepped surface of the chamber simultaneously. When the receiving space is formed on the inner wall of the cavity, the opening of the receiving space faces the constraint ring; When the receiving space is formed on the stepped surface of the cavity, the opening of the receiving space faces the support of the constraint ring.

7. The lower electrode assembly as described in claim 5, characterized in that, The support portion of the constraint ring is provided with an annular groove for placing one or more of the capacitors.

8. The lower electrode assembly as described in any one of claims 1 to 7, characterized in that, The capacitor has a fixed capacitance value or an adjustable capacitance value.

9. The lower electrode assembly as described in any one of claims 1 to 7, characterized in that, The capacitor may contain multiple capacitor elements connected in series or multiple capacitor elements connected in parallel.

10. The lower electrode assembly as described in any one of claims 1 to 7, characterized in that, Multiple capacitors are provided between the constraint ring and the cavity of the reaction chamber, and the multiple capacitors are evenly distributed along the circumference of the constraint ring.

11. The lower electrode assembly as described in any one of claims 1 to 7, characterized in that, The upper surface of the constraint ring is provided with a protective layer resistant to plasma corrosion; The surface of the constraint ring that contacts the cavity of the reaction chamber is insulated.

12. A plasma processing apparatus, characterized in that, include: A reaction chamber connected to a gas supply device; the reaction chamber is provided with a lower electrode assembly as described in any one of claims 1 to 11; The gas introduced into the reaction chamber is excited by radio frequency energy coupled into the reaction chamber to form plasma, which is used to process the substrate placed on the base at the bottom of the reaction chamber; An exhaust pump connected to the reaction chamber is used to discharge reaction byproducts from the reaction chamber; A constraint ring is arranged around the periphery of the base and located between the base and the cavity of the reaction chamber, for constraining the plasma generated within the reaction chamber; A capacitor is disposed between the constraint ring and the cavity of the reaction chamber; the capacitance value between the constraint ring and the cavity is obtained by connecting the device capacitance between the constraint ring and the cavity and the capacitance of the capacitor in parallel.

13. The plasma processing apparatus as described in claim 12, characterized in that, The capacitance between the constraint ring and the cavity can be changed by adjusting the current capacitance value or by replacing it with another capacitor that has a different capacitance value.

14. The plasma processing apparatus as claimed in claim 12, characterized in that, The source radio frequency power used to provide radio frequency energy to generate plasma is 35kW to 50kW.

15. The plasma processing apparatus according to any one of claims 12 to 14, characterized in that, Also includes: An electrostatic chuck, mounted on top of the base, is used to secure the substrate. The focusing ring and edge ring surrounding the electrostatic chuck are used to adjust the electric field or temperature distribution around the substrate; A grounding ring surrounding the base is used to form a radio frequency grounding loop; An isolation ring located between the grounding ring and the base provides electrical isolation between the base and the grounding ring.

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