A plasma processing device and a retractable sealing part thereof

Abstract

A plasma processing device and a retractable sealing part thereof, wherein the retractable sealing part is arranged in or near a radio frequency circuit of the plasma processing device, the retractable sealing part comprises a bellows assembly having a first end and a second end, an isolation ring is added to the upper and lower parts of the bellows assembly to weaken longitudinal radio frequency coupling, and a metal sleeve is added to the inner and outer sides of the bellows assembly to shield transverse radio frequency coupling. The present invention effectively shields radio frequency coupling and obtains a stable radio frequency circuit and etching rate while maintaining the functions of vacuum isolation and retractability of the retractable sealing part.

Description

Technical Field

[0001] The invention relates to the field of semiconductor equipment manufacturing, and in particular to a plasma processing device and a retractable sealing part thereof. Background Art

[0002] In the field of semiconductor equipment, stainless steel bellows are used in many locations inside the cavity, such as around the support shaft of the support base, between the support shaft of the support base and the cavity, and between the movable grounding ring and the fixed grounding ring. The stainless steel bellows in these locations are located in or near the RF loop, which will cause many problems.

[0003] Specifically, taking the bellows disposed between the mobile grounding ring and the fixed grounding ring as an example, with the continuous advancement of technology nodes, the control requirements of the etching process on key dimensions have been further improved, and advanced processes such as All-In-One have been adopted for 14nm and below nodes. For the All-In-One process, the variable plate spacing (Gap) can effectively increase the process window and reduce the difficulty of adjustment. Therefore, the etching equipment for the All-In-One process needs to be equipped with an upper and lower plate design that can move relative to each other. In order to achieve this function, a bellows structure with retractable characteristics and that can isolate the vacuum is one of the necessary components, and the stainless steel bellows is adopted due to its large telescopic stroke and good mechanical strength.

[0004] However, the inventors have found that there are at least the following problems in the prior art. In a complex RF environment, stainless steel bellows have the following disadvantages: 1. Under different telescopic strokes, there are varying capacitance and inductance between the stainless steel foils, resulting in poor impedance stability; 2. Stainless steel materials have higher resistivity than copper and aluminum materials. When RF current passes through, there is a non-negligible heat energy loss. Due to the above factors, it was found during the testing of existing products that when the stainless steel bellows is located in or close to the RF loop, uncertain series or parallel resonance is easily generated inside the cavity, which leads to unstable etching rate.

[0005] The statements herein merely provide background art related to the present invention and do not necessarily constitute prior art. Summary of the invention

[0006] The object of the present invention is to provide a plasma processing device and a retractable sealing part thereof, which effectively shields the RF coupling and obtains a stable RF circuit and etching rate while maintaining the vacuum isolation and retractable functions of the retractable sealing part.

[0007] In order to achieve the above object, the present invention provides a retractable sealing portion, which is arranged in or near a radio frequency circuit of a plasma processing device, and the retractable sealing portion comprises:

[0008] a bellows assembly comprising a first end and a second end;

[0009] A sleeve assembly comprises a first sleeve and a second sleeve, wherein the first sleeve is arranged near the first end of the bellows assembly, and the second sleeve is arranged near the second end of the bellows assembly; the free ends of the first sleeve and the second sleeve overlap each other to form a radio frequency shielding space when the first sleeve and the second sleeve slide relative to each other; the bellows assembly is located in the radio frequency shielding space; wherein the sleeve assembly is a conductor. The sleeve assembly shields lateral radio frequency coupling to obtain a stable radio frequency loop and etching rate.

[0010] The retractable sealing portion also includes a flange assembly, which includes a first flange and a second flange, the first flange is connected to the first end of the bellows assembly, and the second flange is connected to the second end of the bellows assembly; the non-free end of the first sleeve is detachably disposed on the first end of the bellows assembly through the first flange, and the non-free end of the second sleeve is detachably disposed on the second end of the bellows assembly through the second flange.

[0011] At least one sealing ring is arranged on the first flange at a side away from the bellows assembly, and at least one sealing ring is arranged on the second flange at a side away from the bellows assembly to isolate vacuum.

[0012] The bellows assembly is a stainless steel foil.

[0013] An isolation ring is provided on the first flange at a side away from the bellows assembly, and an isolation ring is also provided on the second flange at a side away from the bellows assembly to weaken longitudinal RF coupling and obtain a stable RF loop and etching rate.

[0014] The retractable sealing portion further comprises a fastener, and the fastener is used to fix the first flange, the second flange and / or the isolation ring.

[0015] On the one hand, the isolation ring is made of metal material.

[0016] On the other hand, the isolation ring is made of insulating material.

[0017] At least one sealing ring is arranged between the isolation ring and the first flange, and at least one sealing ring is arranged between the isolation ring and the second flange to isolate the vacuum.

[0018] The sleeve assembly is arranged on both sides of the bellows assembly, or on one side of the bellows assembly close to the radio frequency loop.

[0019] The first sleeve is arranged at the outer side away from the bellows assembly or close to the inner side of the bellows assembly, and correspondingly, the second sleeve is arranged at the inner side close to the bellows assembly or away from the outer side of the bellows assembly; the first sleeve and the second sleeve always maintain partial overlap in the vertical direction.

[0020] The first sleeve and / or the second sleeve is an integrated structure or a split structure.

[0021] The first sleeve and the second sleeve are made of surface-treated metal material.

[0022] An insulating buffer layer is arranged between the first sleeve and the second sleeve, and the insulating buffer layer contacts the first sleeve and the second sleeve respectively and ensures that the first sleeve and the second sleeve do not contact each other, so as to avoid unstable local contact and also avoid the generation of friction particles.

[0023] The insulating buffer layer is made of insulating material.

[0024] The second sleeve is provided with a slot for accommodating the insulating buffer layer.

[0025] The insulating buffer layer is adhered to the first sleeve or the second sleeve.

[0026] The present invention also provides a plasma processing device, comprising:

[0027] Reaction chamber;

[0028] An upper electrode disposed in the cavity and a lower electrode disposed opposite to the upper electrode, wherein the relative positions of the upper electrode and the lower electrode are adjustable, so that the spacing between the upper electrode and the lower electrode is adjustable;

[0029] At least one radio frequency power source is connected to the upper electrode or the lower electrode;

[0030] The retractable sealing portion is arranged in or near the radio frequency loop between the upper electrode and the lower electrode, and the retractable sealing portion retracts and contracts as the relative positions of the upper electrode and the lower electrode change.

[0031] The lower electrode is fixed to the conductive support rod and is located above the bottom wall opening of the reaction chamber. The driving device fixed to the lower end of the conductive support rod drives the conductive support rod to move axially to achieve position adjustment of the lower electrode.

[0032] An electrostatic chuck is arranged on the lower electrode, and the electrostatic chuck supports and clamps the wafer.

[0033] The retractable sealing part provided by the present invention adds isolation rings at the upper and lower parts of the bellows assembly to weaken the longitudinal RF coupling, and adds metal sleeves at the inner and outer sides of the bellows assembly to shield the lateral RF coupling, so that a stable RF loop can be obtained, and the etching rate has better stability and repeatability. Compared with the traditional bellows structure, it is more suitable for use in the RF loop area. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic cross-sectional structure diagram of a plasma processing device provided in an embodiment of the present invention.

[0035] Figure 2 It is a schematic cross-sectional structure diagram of a retractable sealing portion provided in one embodiment of the present invention.

[0036] Figure 3 It is a schematic cross-sectional structure diagram of a retractable sealing portion provided in another embodiment of the present invention.

[0037] Figure 4 It is a schematic cross-sectional structure diagram of a retractable sealing portion provided in the third embodiment of the present invention.

[0038] Figure 5 It is a schematic cross-sectional structure diagram of a retractable sealing portion provided in the fourth embodiment of the present invention.

[0039] Figure 6 It is a schematic cross-sectional structure diagram of a retractable sealing portion provided in the fifth embodiment of the present invention.

[0040] Figure 7 and Figure 8 It is the experimental data graph of etching rate. DETAILED DESCRIPTION

[0041] The following is based on Figures 1 to 8 , specifically describe the preferred embodiments of the present invention.

[0042] like Figure 1As shown, in one embodiment of the present invention, a plasma processing device 1 is provided, and the plasma processing device 1 has a processing chamber, and the processing chamber is a closed space surrounded by a cavity 100 and other necessary components, so that the wafer can complete the etching process in the vacuum environment of the processing chamber. An upper electrode 102 and a lower electrode 105 arranged opposite to the upper electrode 102 are arranged in the cavity 100, and the lower electrode 105 is arranged in a base, and the base is used to support the wafer to be processed, and the base is arranged on a conductive support rod 110, and the lower end of the conductive support rod 110 is fixed to a driving device (not shown in the figure), and the driving device is used to drive the conductive support rod 110 and the base to move along their axial direction. Usually, the gas shower head is fixed above the processing chamber as the upper electrode 102, and an inlet (not shown in the figure) connected to the gas shower head is provided on the end surface outside the processing chamber, and a vent (not shown in the figure) is provided on the gas shower head in the processing chamber. The process gas enters the gas shower head through the inlet and is transported into the processing chamber through the vent. A reaction area is formed between the upper electrode 102 and the lower electrode 105. At least one RF power source is applied to one of the upper electrode 102 or the lower electrode 105 through a RF matcher, and a RF electric field is generated between the upper electrode 102 and the lower electrode 105 to dissociate the process gas into plasma, thereby processing the wafer. As an optional embodiment, the lower electrode 105 is connected to the output end of the RF matcher through a conductive support rod 110, and the RF matcher is connected to the RF power source (not shown in the figure), so as to provide RF power to the lower electrode 105. An electrostatic chuck 107 is provided on the base for adsorbing the wafer.

[0043] In some embodiments, the lower electrode 105 can be connected to one or more RF matches, for example, two RF matches. In the embodiment where multiple RF matches are connected, each RF match can provide a different RF frequency and power from other RF matches to meet the requirements of different processing techniques. In these embodiments, the upper electrode 102 can be grounded. In other embodiments, the lower electrode 105 can be connected to one RF match, and the upper electrode 102 can be connected to another RF match. The two RF matches can provide different RF frequencies and powers.

[0044] In this embodiment, the lower electrode 105 is connected to an RF power source through an RF matcher to provide RF power, the upper electrode 102 and the cavity 100 can be grounded, and the cavity 100 or some other accessories electrically connected to the cavity can serve as a return path for the RF power. Specifically, Figure 1As shown by the solid line in the figure, the RF power is output from the output end of the RF matcher, passes through the conductive support rod 110, and enters the lower electrode 105. Then the RF current flows into the upper electrode 102 through the plasma between the upper and lower electrodes, and returns to the loop end of the RF matcher through the RF loop in the cavity 100. The return path can have different settings according to different cavity structures and design requirements.

[0045] The RF matcher is connected to the RF power supply and is used to output the required RF power. The RF matcher has an output end and a loop end. The output end is used to output the RF power and the loop end is used to receive the returned RF power. The RF filter is connected to the RF matcher and is used to filter the interference frequency signal.

[0046] The processing chamber of the plasma processing device is a closed space surrounded by a cavity 100 and other necessary components, so that the wafer can complete the etching process in the vacuum environment of the processing chamber. In this embodiment, an upper electrode 102 is arranged on the top of the cavity 100. The upper electrode 102 can be arranged inside the cavity 100. The sealing of the top of the cavity 100 is achieved through other components, such as an upper cover plate and other structures. The upper electrode 102 can also be embedded in the top of the cavity 100. Here, the arrangement of the upper electrode 102 is only an example. The present application does not limit the arrangement method of the upper electrode 102 and the sealing of the top of the cavity 100.

[0047] In this embodiment, the cavity 100 includes a side wall 1001 and a bottom wall 1002 , and the lower electrode 105 is located above the opening of the bottom wall 1002 , so that the conductive support rod 110 can move up and down at the opening.

[0048] In this embodiment, an insulating ring 142 is arranged around the lower electrode 105, and the insulating ring 142 is fixed to the lower electrode 105. A movable grounding ring 136 is fixedly arranged on the outer side of the insulating ring 142. The insulating ring 142 is made of an insulating material, such as a ceramic material, and electrically isolates the lower electrode 105 from the movable grounding ring 136. The movable grounding ring 136 is a conductive material, and the movable grounding ring 136 serves as a part of the RF return path. A fixed grounding ring 101 is also arranged in the cavity 100. The fixed grounding ring 101 is a conductive material, and is also a part of the RF return path. It is located on the outer side of the movable grounding ring 136, and there is a gap between the fixed grounding ring 101 and the movable grounding ring 136. The movable grounding ring 136 is used to shield the RF interference between the lower electrode 105 and the fixed grounding ring 101. A cavity 103 is formed between the fixed grounding ring 101 and the cavity 100. The cavity 103 is used to form an exhaust cavity. A plasma confinement ring 134 is arranged on the cavity 103. The plasma confinement ring 134, the fixed grounding ring 101, and the cavity 100 form an exhaust cavity. At the same time, the plasma confinement ring 134 includes a conductive component. Among them, the fixed grounding ring 101 is a conductive isolation wall. On the one hand, it can be used as a radio frequency return path, and on the other hand, it can isolate the space of the exhaust cavity in the horizontal direction. The plasma confinement ring 134 is a breathable structure, so that the excess plasma in the cavity is extinguished and the exhaust gas enters the exhaust cavity. Usually, the exhaust cavity is also provided with an air pump, and the exhaust gas in the chamber is discharged by the air pump. After the radio frequency current passes through the plasma confinement ring 134 from the cavity side wall 1001, it enters the fixed grounding ring 101. In this way, the exhaust cavity 103 and the plasma confinement ring 134 in the chamber are used as necessary components to realize the return path of the radio frequency current, which can effectively shorten the return path of the radio frequency current.

[0049] In this embodiment, a retractable sealing portion 140 is provided between the movable grounding ring 136 and the fixed grounding ring 101, for sealing the upper surface of the lower electrode 105 in the accommodation space where the cavity 100 is located. Figure 1As shown, the enclosed space at the bottom of the cavity 100 is surrounded by the side wall of the fixed grounding ring 101, the inner wall of the retractable sealing part 140 and the side wall of the movable grounding ring 136, so that the upper surface 105 of the lower electrode 105 is placed in the cavity 100, and the lower surface of the lower electrode 105 and the conductive support rod 110 are placed outside the enclosed environment of the cavity 100, and the cavity 100 will provide a vacuum environment for the etching process. The retractable sealing part 140 is retracted up and down with the axial movement of the conductive support rod 110, that is, the retractable sealing part 140 and the conductive support rod 110 have the same moving direction, and the upper surface of the lower electrode 105 here is toward the surface of the upper electrode 102. In this way, when the conductive support rod 110 is driven to move up and down, the retractable sealing part 140 will be retracted together with the lower electrode 105, and at the same time, the lower electrode 105 is sealed to the cavity 100 by the retractable sealing part 140. It can be understood that the retractable sealing portion 140 can be directly or indirectly fixed to the lower electrode 105. When other components are provided in the cavity 100, the retractable sealing portion 140 can cooperate with the other components. The retractable sealing portion 140 is generally provided in the RF circuit or near the RF circuit of the plasma processing device, thereby achieving sealing of the bottom of the cavity, so that the surface of the lower electrode 105 facing the upper electrode 102 is located in the closed chamber.

[0050] A conductive strip 160 is also provided on the cavity 100, and the conductive strip 160 is connected between the movable grounding ring 136 and the fixed grounding ring 101. The length of the conductive strip 160 is adapted to the expansion and contraction amount of the retractable sealing part 140. The conductive strip 160 can be a flexible conductive material, for example, it can be metal copper. The length of the conductive strip 160 has a certain margin. When the retractable sealing part 140 is expanded and contracted up and down, it can still ensure that the movable grounding ring 136 and the fixed grounding ring 101 maintain a good electrical connection state, thereby forming a complete radio frequency circuit.

[0051] The complete RF circuit is attached Figure 1 The solid arrow in the middle shows that the RF current flows into the upper electrode 105 through the conductive support rod 110, and then flows into the upper electrode 102 through the plasma between the upper and lower electrodes, and then flows through the inner side of the cavity 100 to the upper surface of the middle grounding ring below the plasma confinement ring 134, and then flows through the inner side of the fixed grounding ring 101 to the outer side of the conductive strip 160, and then flows to the outer side of the movable grounding ring 136, and then turns back to flow to the inner side of the movable grounding ring 136, and finally, flows through the inner side of the conductive strip 160 to the fixed grounding ring 101, thereby returning to the loop end of the RF matcher to form a complete RF loop.

[0052] Since the main part of the retractable sealing part 140 is a stainless steel bellows, when the stainless steel bellows is located at or close to the radio frequency loop, uncertain series or parallel resonance is easily generated inside the cavity, such as Figure 1 As shown, the inner surface of the fixed grounding ring 101 and the inner and outer surfaces of the mobile grounding ring 136 are the necessary routes for the RF loop. The stainless steel bellows is used to connect the two and seal the vacuum. There is a millimeter-level gap between the two ends of the stainless steel bellows and the RF loop. Although the capacitance is very small, there is still a risk of RF coupling (especially high frequency), which will cause a certain amount of energy loss. Figure 1 As shown by the dotted arrows in the figure, longitudinal RF coupling will be generated from the upper and lower ends of the stainless steel bellows, and transverse RF coupling will also be generated from the sides of the stainless steel bellows. These RF couplings will lead to instability in the etching rate.

[0053] In order to solve the RF coupling shielding problem of the retractable sealing part exposed in the RF area, the present application provides a retractable sealing part, which is generally arranged in the RF circuit or near the RF circuit of the plasma processing device. Figure 1 As shown, in one embodiment, two ends of the retractable sealing portion 140 are respectively connected to the fixed grounding ring 101 and the movable grounding ring 136 .

[0054] like Figure 2 As shown, the retractable sealing part 140 includes a bellows assembly 11 having a first end and a second end. The bellows assembly 11 is annular in shape and surrounds the conductive support rod 110. The bellows assembly 11 is a stainless steel foil. The first end is directly connected to the movable grounding ring 136 through the first flange 131, and the second end is directly connected to the fixed grounding ring 101 through the second flange 132. The first flange 131 and the second flange 132 are made of surface-treated metal materials, including but not limited to copper, aluminum, nickel, etc. In this embodiment, a sealing ring 15 is provided between the first flange 131 and the movable grounding ring 136, and a sealing ring 15 is provided between the second flange 132 and the fixed grounding ring 101 to achieve sealing and vacuum isolation.

[0055] In order to shield the RF coupling flowing to the bellows assembly 11, a sleeve assembly is provided on the side of the bellows assembly 11 close to the conductive strip 160 (i.e., the inner side) and the side of the bellows assembly 11 close to the side wall 1001 (i.e., the outer side), and the sleeve assembly includes a first sleeve 121 and a second sleeve 122. The first sleeve 121 is provided close to the first end of the bellows assembly 11, and the second sleeve 122 is provided close to the second end of the bellows assembly 11. The first sleeve 121 is a first shielding body, and the second sleeve 122 is a second shielding body, and the two form a shielding space. The non-free end of the first sleeve 121 is detachably provided at the first end of the bellows assembly 11 through the first flange 131, and the first sleeve 121 can move up and down with the first flange 131. The non-free end of the second sleeve 122 is detachably provided at the second end of the bellows assembly 11 through the second flange 132, and the second sleeve 122 can move up and down with the second flange 132. The free ends of the first sleeve 121 and the second sleeve 122 always maintain partial overlap in the vertical direction during the extension and retraction process of the bellows assembly 11, so as to form a radio frequency shielding space when the first sleeve 121 and the second sleeve 122 slide relative to each other, so that the bellows assembly 11 is always completely located in the radio frequency shielding space. The overlapping positions of the first sleeve 121 and the second sleeve 122 are interchangeable, and the first sleeve 121 can be set on the inner side close to the bellows assembly 11, and the second sleeve 122 can be set on the outer side away from the bellows assembly 11, or vice versa, the first sleeve 121 can be set on the outer side and the second sleeve 122 can be set on the inner side. In this embodiment, the first sleeve 121 and the second sleeve 122 are made of surface-treated metal materials, including but not limited to copper, aluminum, nickel, etc. The radio frequency circuit of this embodiment is specifically: the radio frequency current flows from the fixed grounding ring 101 through the side of the sleeve assembly close to the side wall 1001 into the movable grounding ring 136 (see the radio frequency current). Figure 2 As shown in the figure (black arrow in the middle), since the sleeve assembly is a metal conductor and the bellows assembly 11 is located in the RF shielding space, the RF current can be blocked from coupling into the bellows assembly 11, thereby obtaining a stable RF circuit and etching rate.

[0056] For a specific embodiment of the sleeve assembly, Figure 3An embodiment is shown in which a sleeve assembly is provided only on one side close to the side wall 1001. In this embodiment, the first sleeve 121 includes a ring extending in the longitudinal direction, and the second sleeve 122 also includes a ring extending in the longitudinal direction; as an optional way of fixing the sleeve assembly, a lateral extension portion is provided at the non-free end of the first sleeve 121, and a lateral extension portion is also provided at the non-free end of the second sleeve 122, and an annular groove is provided on the side of the first flange and the second flange close to the side wall 1001, and the annular groove is used to clamp the lateral extension portions of the first sleeve 121 and the second sleeve 122, and the flange is fixed to the grounding ring by fasteners, and the groove between the grounding ring and the flange clamps the sleeve to form a fixed connection, and the fastener can be a screw. The RF circuit of this embodiment is specifically as follows: the RF current flows from the fixed grounding ring 101 through the side of the sleeve assembly close to the side wall 1001 into the movable grounding ring 136 (refer to the RF current). Figure 3 As shown in the figure (black arrow in the middle), since the sleeve assembly is a conductor and the bellows assembly 11 is located in the RF shielding space, the RF current can be blocked from coupling into the bellows assembly 11, thereby obtaining a stable RF circuit and etching rate.

[0057] For a specific embodiment of the sleeve assembly, Figure 4 An embodiment is shown in which sleeve assemblies are provided on both the side (i.e., the inner side) of the bellows assembly 11 close to the conductive strip 160 and the side (i.e., the outer side) close to the side wall 1001. In this embodiment, the first sleeve 121 includes an integrated "concave" body, and the second sleeve 122 includes two independent rings extending in the longitudinal direction. The two rings are concentrically arranged. Of course, the shapes of the first sleeve 121 and the second sleeve 122 can be interchanged. Optionally, both the first sleeve 121 and the second sleeve 122 are "concave" bodies or two independent rings. For the fixation when the sleeve is a "concave" body, the flange and the sleeve are optionally fixed to the grounding ring by fasteners 171. In this embodiment, the first flange 131 is fixed to the mobile grounding ring 136 by fasteners 171, and the second flange 132 is fixed to the fixed grounding ring 101 by fasteners 172. The fasteners are also made of surface-treated metal materials, including but not limited to copper, aluminum, nickel, etc. When the sleeve is two independent rings, the above-mentioned groove and lateral extension can also be used for fixing, which will not be described in detail here. The RF circuit of this embodiment is as follows: RF current flows from the fixed grounding ring 101 through the side of the sleeve assembly close to the side wall 1001 into the movable grounding ring 136 (see RF current Figure 4 As shown in the figure (black arrow in the middle), since the sleeve assembly is a conductor and the bellows assembly 11 is located in the RF shielding space, the RF current can be blocked from coupling into the bellows assembly 11, thereby obtaining a stable RF circuit and etching rate.

[0058] like Figure 5 As shown, another embodiment is shown, in which an isolation ring 14 with a certain thickness is provided between the first flange 131 and the movable grounding ring 136, and an isolation ring 14 is also provided between the second flange 132 and the fixed grounding ring 101. In this embodiment, the isolation ring 14 is also made of a surface-treated metal material, including but not limited to copper, aluminum, nickel, etc. The RF circuit of this embodiment is specifically as follows: the RF current flows from the fixed grounding ring 101 through the side of the sleeve assembly close to the side wall 1001 and then through the isolation ring 14 into the movable grounding ring 136 (refer to the RF current Figure 5 (black arrow in the middle), since the sleeve assembly and the isolation ring 14 are conductors, the bellows assembly 11 is located in the RF shielding space, so the RF current can be blocked from coupling into the bellows assembly 11, thereby obtaining a stable RF circuit and etching rate. In this embodiment, a sealing ring 15 is provided between the isolation ring 14 and the first flange 131 and the second flange 132 to isolate the vacuum. Isolation rings are added to the upper and lower parts of the bellows assembly to weaken the longitudinal RF coupling, so that a stable RF circuit and etching rate can be obtained.

[0059] Figure 6 Another optional embodiment is shown. In this embodiment, the isolation ring 14 is made of insulating material, which can be ceramic or a material with a lower dielectric constant, including but not limited to alumina, aluminum nitride, quartz, polyetherimide, Peek, etc. The RF circuit of this embodiment is specifically as follows: RF current flows from the fixed grounding ring 101 through the conductive strip 160 into the movable grounding ring 136 (see RF current Figure 6 As shown in the figure, since the isolation ring 14 is an insulator and the bellows assembly 11 is located in the RF shielding space, the RF current can be blocked from coupling into the bellows assembly 11, thereby obtaining a stable RF circuit and etching rate. Isolation rings are added to the upper and lower parts of the bellows assembly to weaken the longitudinal RF coupling, thereby obtaining a stable RF circuit and etching rate.

[0060] For the free ends of the first sleeve 121 and the second sleeve 122, optionally, the first sleeve 121 and the second sleeve 122 can be arranged in close contact, but this may lead to uneven distribution of RF circumferentially due to inconsistent contact tightness between each other, and the frequent mutual friction movement between the first sleeve 121 and the second sleeve 122 will also produce particulate matter, which has an adverse effect on the process. In an optional embodiment, an insulating buffer layer 16 is arranged between the first sleeve 121 and the second sleeve 122, and the insulating buffer layer 16 contacts the first sleeve 121 and the second sleeve 122 respectively. The thickness of the insulating buffer layer 16 cannot be too thin, and it should ensure that the first sleeve 121 and the second sleeve 122 are not in contact with each other, and the thickness cannot be too thick, and it should ensure that the gap between the first sleeve 121 and the second sleeve 122 can conduct RF current. The insulating buffer layer 16 can be directly adhered to the first sleeve 121 or the second sleeve 122, or a slot can be provided on the first sleeve 121 or the second sleeve 122 to accommodate the insulating buffer layer 16. The insulating buffer layer 16 is made of insulating material, including but not limited to aluminum oxide, aluminum nitride, quartz, polyetherimide, Peek (polyetheretherketone), etc. The first sleeve 121 and the second sleeve 122 are isolated by the insulating buffer layer 16 to avoid unstable local contact and also to avoid the generation of friction particles.

[0061] The retractable sealing part provided by the present invention also has the functions of isolating vacuum and being retractable through the sealing ring and the double-layer sleeve structure. Furthermore, an isolation ring is added to the upper and lower parts of the bellows assembly to weaken the longitudinal RF coupling, and a metal sleeve is added to the inner and outer sides of the bellows assembly to shield the lateral RF coupling, so that a stable RF circuit and etching rate can be obtained. Compared with the traditional bellows structure, it is more suitable for use in the RF circuit area. Using different isolation ring materials, using different metal sleeve materials, using a similar double-layer sleeve structure for local RF shielding, etc. are all variations of the embodiments of the present invention.

[0062] The SD-RIE 9900 experiment was conducted to verify the effectiveness of the retractable sealing portion provided by the present invention in shielding radio frequency coupling.

[0063] like Figure 7 As shown, the X-axis is the distance between the upper and lower electrodes, the Y-axis is the etching rate, the solid line is the test data obtained by using the retractable sealing portion provided by the present invention, and the dotted line is the test data obtained without using the retractable sealing portion provided by the present invention. Figure 7 It can be seen that the use of the retractable sealing portion provided by the present invention has a better stability of the etching rate (no longer jumping up and down). Figure 8As shown, the X-axis is the distance between the upper and lower electrodes, the Y-axis is the etching rate, the dotted line is the test data obtained by using the retractable sealing part provided by the present invention to perform the first process, and the solid line is the test data obtained by using the retractable sealing part provided by the present invention to perform the second process. Figure 8 It can be seen that the etching rate has good repeatability (double line overlap) using the retractable sealing portion provided by the present invention.

[0064] Experimental data show that the retractable sealing portion provided by the present invention can effectively prevent radio frequency coupling and reduce the heat energy loss caused by the stainless steel foil. The etching rate data of the cavity using this retractable sealing portion has better stability and repeatability.

[0065] It should be noted that, in the embodiments of the present invention, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0066] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A retractable sealing portion, characterized in that: The retractable sealing portion is arranged in or near a radio frequency circuit of a plasma processing device, and the retractable sealing portion comprises: a bellows assembly comprising a first end and a second end; A sleeve assembly, comprising a first sleeve and a second sleeve, wherein the first sleeve is disposed near a first end of the bellows assembly and the second sleeve is disposed near a second end of the bellows assembly; The free ends of the first sleeve and the second sleeve overlap each other to form a radio frequency shielding space when the first sleeve and the second sleeve slide relative to each other; the bellows assembly is located in the radio frequency shielding space; wherein the sleeve assembly is a conductor; An insulating buffer layer is provided between the first sleeve and the second sleeve, and the insulating buffer layer contacts the first sleeve and the second sleeve respectively, and ensures that the first sleeve and the second sleeve are The second sleeves do not contact each other.

2. The retractable sealing portion according to claim 1, characterized in that The retractable sealing portion also includes a flange assembly, which includes a first flange and a second flange, the first flange is connected to the first end of the bellows assembly, and the second flange is connected to the second end of the bellows assembly; the non-free end of the first sleeve is detachably disposed on the first end of the bellows assembly through the first flange, and the non-free end of the second sleeve is detachably disposed on the second end of the bellows assembly through the second flange.

3. The retractable sealing portion according to claim 2, characterized in that: At least one sealing ring is arranged on the first flange at a side away from the bellows assembly, and at least one sealing ring is arranged on the second flange at a side away from the bellows assembly.

4. The retractable seal according to claim 1, wherein: The bellows assembly is a stainless steel foil.

5. The retractable sealing portion according to claim 2, characterized in that: An isolating ring is arranged on the first flange at a side away from the bellows assembly, and an isolating ring is also arranged on the second flange at a side away from the bellows assembly.

6. The retractable seal according to claim 5, characterized in that Also included are fasteners, which are used to fix the first flange, the second flange and / or the isolation ring.

7. The retractable seal according to claim 5, wherein: The isolation ring is made of metal material.

8. The retractable seal according to claim 5, wherein: The isolation ring is made of insulating material.

9. The retractable seal according to claim 5, wherein: At least one sealing ring is arranged between the isolation ring and the first flange, and at least one sealing ring is arranged between the isolation ring and the second flange.

10. The retractable seal according to claim 1, wherein: The sleeve assembly is arranged on both sides of the bellows assembly, or on one side of the bellows assembly close to the radio frequency loop.

11. The retractable seal according to claim 1, wherein: The first sleeve is arranged at the outer side away from the bellows assembly or close to the inner side of the bellows assembly, and correspondingly, the second sleeve is arranged at the inner side close to the bellows assembly or away from the outer side of the bellows assembly; the first sleeve and the second sleeve always maintain partial overlap in the vertical direction.

12. The retractable seal according to claim 11, wherein: The first sleeve and / or the second sleeve is an integrated structure or a split structure.

13. The retractable seal according to claim 12, wherein: The first sleeve and the second sleeve are made of surface-treated metal material.

14. The retractable seal according to claim 12, wherein: The insulating buffer layer is made of insulating material.

15. The retractable seal according to claim 12, wherein: The second sleeve is provided with a slot for accommodating the insulating buffer layer.

16. The retractable seal according to claim 12, wherein: The insulating buffer layer is adhered to the first sleeve or the second sleeve.

17. A plasma processing device, characterized in that: Include: Reaction chamber; An upper electrode disposed in the cavity and a lower electrode disposed opposite to the upper electrode, wherein the relative positions of the upper electrode and the lower electrode are adjustable, so that the spacing between the upper electrode and the lower electrode is adjustable; At least one radio frequency power source is connected to the upper electrode or the lower electrode; The retractable sealing portion as described in any one of claims 1 to 16 is arranged in or near the radio frequency loop between the upper electrode and the lower electrode, and the retractable sealing portion retracts and contracts as the relative position of the upper electrode and the lower electrode changes.

18. The plasma processing apparatus according to claim 17, wherein: The lower electrode is fixed to the conductive support rod and is located above the bottom wall opening of the reaction chamber. The driving device fixed to the lower end of the conductive support rod drives the conductive support rod to move axially to achieve position adjustment of the lower electrode.

19. The plasma processing apparatus according to claim 17, wherein: An electrostatic chuck is arranged on the lower electrode, and the electrostatic chuck supports and clamps the wafer.

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