Plasma etching machine and assistive electric field diameter changing device thereof

Abstract

An assistive electric field diameter changing device of a plasma etching machine, comprising shielding plates. The shielding plates can shield an electric field, and a through hole is formed in the middle of each shielding plate; each shielding plate is an integral plate, a plurality of shielding plates are provided, and the sizes of the through holes of the shielding plates are different; or the shielding plates comprise a plurality of movable shielding plates, and the movable shielding plates are connected to each other and define a size-adjustable through hole. The assistive electric field diameter changing device of the plasma etching machine is provided with shielding plates capable of shielding an electric field, and the size of the through hole of the shielding plate is adjustable, so as to adjust the diameter of the electric field, so that etching uniformity can be improved by changing the electric field when there is a problem with the etching uniformity of the plasma etching machine.

Description

Plasma etching machine and auxiliary electric field diameter reducing device thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 25, 2023, with application number 202311089216.5 and invention name “Plasma etcher and its auxiliary electric field diameter reducing device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of semiconductor processing equipment, and more particularly to an auxiliary electric field diameter-changing device of a plasma etcher, and also includes a plasma etcher. Background Art

[0003] A plasma etcher, used in the semiconductor processing industry, is shown in Figure 1. It includes a plasma reaction chamber 013, a plasma coupling coil 001, a ceramic dielectric window 002, an excitation source RF power supply 011, an excitation source matching network 010, a shielding cover 009, a gas source 012, an air nozzle 003, a bias electrode 006, a bias RF power supply 015, a bias matching network 014, a pressure control valve 007, and a vacuum pump 008. Shielding cover 009 is connected to plasma reaction chamber 013, with ceramic dielectric window 002 positioned between them. Plasma coupling coil 001 is positioned within shielding cover 009, and bias electrode 006 is positioned within plasma reaction chamber 013.

[0004] During operation, the process gas provided by the gas source 012 is sprayed into the plasma reaction chamber 013 through the air nozzle 003 installed on the ceramic dielectric window 002, and plasma is generated in the area 004 under the action of the plasma coupling coil 001; the bias electrode 006 provides a bias voltage under the action of the bias RF power supply 015 and the bias matching network 014, accelerating the plasma and causing it to bombard the substrate sheet 005.

[0005] However, the structure of the plasma coupling coil 001 is fixed, and the electric field it generates basically does not change when the power and voltage conditions do not change. As a result, when problems with etching uniformity arise, the etching uniformity cannot be improved by changing the electric field.

[0006] Therefore, how to effectively improve the uniformity of etching by changing the electric field is an urgent problem to be solved by those skilled in the art.

[0007] Summary of the Invention

[0008] In light of this, the present invention provides an auxiliary electric field diameter-changing device for a plasma etcher. The device comprises a shielding plate capable of shielding the electric field. The shielding plate has adjustable apertures, thereby adjusting the diameter of the electric field. This device can improve etching uniformity by varying the electric field when etching uniformity is compromised. The present invention also provides a plasma etcher employing the auxiliary electric field diameter-changing device, which can improve etching uniformity by varying the electric field.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] An auxiliary electric field diameter-changing device for a plasma etching machine, comprising:

[0011] A shielding plate, the shielding plate can shield the electric field, and a through hole is provided in the middle of the shielding plate;

[0012] The shielding plate is a whole plate, and there are multiple shielding plates, and the through-hole sizes of the shielding plates are different; or

[0013] The shielding plate includes a plurality of movable shielding plates, and the movable shielding plates are connected to each other and surround the through hole with adjustable size.

[0014] Preferably, the auxiliary electric field diameter-changing device further comprises an insulating plate, and each movable shielding plate is movably mounted on the insulating plate along a preset trajectory, and during the movement along the preset trajectory, the size of the through hole surrounded by all the movable shielding plates can change.

[0015] Preferably, in the auxiliary electric field diameter-changing device, the edge of each movable shielding plate overlaps with the adjacent movable shielding plates.

[0016] Preferably, in the above-mentioned auxiliary electric field diameter-changing device, the movable shielding plate includes first movable shielding plates and second movable shielding plates arranged alternately; both side edges of any first movable shielding plate are respectively overlapped on the same side of two adjacent second movable shielding plates; and both side edges of any second movable shielding plate are respectively overlapped on the same side of two adjacent first movable shielding plates.

[0017] Preferably, in the auxiliary electric field diameter-changing device, the movable shielding plates are connected into one body via a connecting plate, and the movable shielding plates are linked via the connecting plate.

[0018] Preferably, in the auxiliary electric field diameter-changing device, the first end of each movable shielding plate surrounds the through hole, and the second end is hinged to the insulating plate respectively; the second end of each movable shielding plate is hinged in sequence through the connecting plate.

[0019] Preferably, in the auxiliary electric field diameter-changing device, a connecting screw is provided at the second end of the movable shielding plate, the connecting screw is passed through the through holes of the two connecting plates, and the two connecting plates can rotate around the connecting screw respectively.

[0020] Preferably, the auxiliary electric field diameter-changing device further comprises an operating rod, which is movably connected to the movable shielding plate and / or the connecting plate, and can drive all the movable shielding plates to move along the preset trajectory during movement of the operating rod.

[0021] Preferably, in the auxiliary electric field diameter-changing device, the operating rod is hinged to the connecting plate;

[0022] The operating rod is provided with an elongated hole for being inserted and fitted with a limit screw.

[0023] Preferably, in the auxiliary electric field diameter-changing device, all the movable shielding plates are located on the same side of the insulating plate, and the connecting plate is located on a side of the movable shielding plate facing the insulating plate.

[0024] Preferably, in the auxiliary electric field diameter-changing device, a recessed portion is provided on a side of the insulating plate facing away from the movable shielding plate, for accommodating a plasma coupling coil of the plasma etcher.

[0025] Preferably, in the auxiliary electric field diameter-changing device, all the movable shielding plates have the same shape, all the first movable shielding plates have the same size, and all the second movable shielding plates have the same size.

[0026] A plasma etcher comprises a shielding cover and a plasma reaction chamber fixedly connected, wherein the space enclosed by the shielding cover and the plasma reaction chamber is divided into a first space and a second space by a dielectric window; a plasma coupling coil is provided in the first space; the plasma etcher further comprises a shower head and an auxiliary electric field diameter reducing device as described in any one of the above technical solutions; the shower head passes through the plasma coupling coil and the dielectric window and extends into the second space; the auxiliary electric field diameter reducing device is arranged between the plasma coupling coil and the dielectric window.

[0027] Preferably, in the above plasma etcher, the operating rod of the auxiliary electric field diameter reducing device extends out of the first space, and the limiting screw of the auxiliary electric field diameter reducing device is fixed to the shielding cover and / or the plasma reaction chamber.

[0028] Preferably, in the above-mentioned plasma etcher, a convex edge is provided on the side of the dielectric window facing the auxiliary electric field diameter-changing device, the convex edge is circled around the outer periphery of the nozzle, and the convex edge is inserted into the through hole of the movable shielding plate; the insulating plate of the auxiliary electric field diameter-changing device is fixed to the convex edge by fasteners.

[0029] Preferably, in the above plasma etcher, a bias electrode is provided in the second space, and a wafer placement plate is arranged on the side of the bias electrode facing the shower head.

[0030] Preferably, in the above-mentioned plasma etcher, the wafer placement plate and the bias electrode are connected via a connecting sleeve sleeved on the periphery of both; a sink groove is provided on the end face of the connecting sleeve, and a wafer positioning ring is installed in the sink groove.

[0031] Preferably, in the above-mentioned plasma etcher, a lining is provided in the plasma reaction chamber, and the bias electrode extends into the lining.

[0032] Preferably, in the above-mentioned plasma etcher, a chamber cover is provided at the open end of the plasma reaction chamber, and the chamber cover extends into the space enclosed by the shielding cover and the plasma reaction chamber; and the dielectric window is installed on the chamber cover.

[0033] Preferably, in the above plasma etcher, the dielectric window and the chamber cover are sealed.

[0034] The present invention provides an auxiliary electric field diameter-changing device for a plasma etcher, comprising a shielding plate, which can shield the electric field and has a through hole in the middle thereof; the shielding plate is a whole plate, and there are multiple shielding plates, each of which has a through hole of different sizes; or the shielding plate comprises multiple movable shielding plates, each of which is interconnected and encloses the through hole of adjustable size.

[0035] When applying the above-mentioned auxiliary electric field diameter-changing device, the shielding plate is arranged between the plasma coupling coil and the dielectric window in the plasma etcher; if the shielding plate is a whole plate, the size of the through hole can be changed by replacing different shielding plates, thereby adjusting the diameter of the electric field; if the shielding plate includes multiple interconnected movable shielding plates, the size of the through hole can be adjusted by moving all the movable shielding plates, thereby adjusting the diameter of the electric field.

[0036] Obviously, the auxiliary electric field diameter-changing device provided by the present invention can adjust the diameter of the electric field by adjusting the size of the through hole, thereby adjusting the distribution of the plasma in the plasma reaction chamber of the plasma etcher acting on the wafer, and then playing a role in adjusting the etching uniformity.

[0037] The present invention also provides a plasma etcher using the auxiliary electric field diameter-changing device, which can improve the uniformity of etching by changing the electric field. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] FIG1 is a schematic structural diagram of a plasma etcher in the prior art;

[0040] FIG2 is a schematic structural diagram of a plasma etcher provided in an embodiment of the present invention;

[0041] FIG3 is a schematic diagram of the interior of a shielding cover provided by an embodiment of the present invention;

[0042] FIG4 is a schematic diagram of the assembly of the auxiliary electric field diameter-changing device and the plasma coupling coil provided in an embodiment of the present invention;

[0043] FIG5 is a schematic diagram of the assembly of the auxiliary electric field diameter-changing device, the plasma coupling coil, and the dielectric window provided in an embodiment of the present invention;

[0044] FIG6 is a schematic structural diagram of the auxiliary electric field diameter-changing device provided by an embodiment of the present invention when the through hole size is minimum;

[0045] FIG7 is a schematic structural diagram of the auxiliary electric field diameter-changing device provided by an embodiment of the present invention when the through hole size is large;

[0046] FIG8 is a schematic structural diagram of the auxiliary electric field diameter-changing device provided by an embodiment of the present invention when the through hole size is the largest;

[0047] In Figures 2 to 8 , the following components are shown: chamber cover 101; connecting plate 102; first connecting plate 1021; second connecting plate 1022; dielectric window 103; insulating plate 104; first movable shielding plate 105; second movable shielding plate 106; plasma coupling coil 107; showerhead 108; shielding cover 109; first hinge shaft 110; connecting screw 111; chamber cover lining 112; operating rod 113; limit screw 114; second hinge shaft 115; bias electrode 116; lining 117; gas source 118; gas guide hood 119; pressure control valve 120; bias matching network 121; bias RF power supply 122; vacuum pump 123; excitation source matching network 124; excitation source RF power supply 125; plasma reaction chamber 126;

[0048] Connecting sleeve 127 ; wafer positioning ring 128 ; wafer placement plate 129 ; wafer 130 . DETAILED DESCRIPTION

[0049] An embodiment of the present invention discloses an auxiliary electric field diameter-changing device for a plasma etcher. The device comprises a shielding plate capable of shielding the electric field. The shielding plate has adjustable apertures, thereby adjusting the diameter of the electric field. This device can improve etching uniformity by changing the electric field when etching uniformity is compromised. The present invention also discloses a plasma etcher employing the auxiliary electric field diameter-changing device, which can improve etching uniformity by changing the electric field.

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Please refer to Figures 2 to 8. An embodiment of the present invention provides an auxiliary electric field diameter-changing device for a plasma etcher, comprising a shielding plate, which can shield the electric field and has a through hole in the middle of the shielding plate; the shielding plate is a whole plate, and there are multiple shielding plates, each of which has a through hole of different sizes; or the shielding plate includes multiple movable shielding plates, each of which is interconnected and surrounds the through hole of adjustable size.

[0052] When applying the above-mentioned auxiliary electric field diameter-changing device, the shielding plate is arranged between the plasma coupling coil 107 and the dielectric window 103 in the plasma etcher; if the shielding plate is a whole plate, the size of the through hole can be changed by replacing different shielding plates, thereby adjusting the diameter of the electric field; if the shielding plate includes multiple interconnected movable shielding plates, the size of the through hole can be adjusted by moving all the movable shielding plates, thereby adjusting the diameter of the electric field.

[0053] Obviously, the auxiliary electric field diameter-changing device provided in this embodiment can adjust the diameter of the electric field by changing the size of the through hole, thereby adjusting the distribution of the plasma in the plasma reaction chamber 126 of the plasma etcher acting on the wafer 130, thereby playing a role in adjusting the etching uniformity.

[0054] The auxiliary electric field diameter-changing device further includes an insulating plate 104 , which is arranged between the shielding plate and the plasma coupling coil 107 .

[0055] Furthermore, in the auxiliary electric field diameter-changing device, each movable shielding plate can be mounted on the insulating plate 104 so as to move along a preset trajectory, and during the movement along the preset trajectory, the size of the through hole surrounded by all the movable shielding plates can change.

[0056] The edge of each movable shielding plate overlaps with the adjacent movable shielding plate to prevent gaps from forming between two adjacent movable shielding plates to cause electric field leakage, thereby ensuring the effect of improving etching uniformity by changing the electric field.

[0057] The movable shielding plate includes first movable shielding plates 105 and second movable shielding plates 106 arranged alternately; both side edges of any first movable shielding plate 105 are respectively overlapped on the same side of two adjacent second movable shielding plates 106; and both side edges of any second movable shielding plate 106 are respectively overlapped on the same side of two adjacent first movable shielding plates 105.

[0058] When the shielding plate provided in this embodiment is applied to a plasma etching machine, the first movable shielding plate 105 and the second movable shielding plate 106 are arranged in an upper and lower direction in an orderly manner.

[0059] Different movable shielding plates 105 can be configured to be movable separately. For example, the movable shielding plates 105 are arranged radially. When adjusting the size of the through hole, the movable shielding plates 105 need to be driven one by one to move along the radial direction of the through hole on the insulating plate.

[0060] However, the operation of driving the movable shielding plates 105 to move on the insulating plate 104 one by one is cumbersome and inconvenient. To solve this problem, the movable shielding plates are preferably connected as a whole via a connecting plate 102, and the movable shielding plates are linked by the connecting plate 102 to avoid driving the movable shielding plates 105 to move one by one.

[0061] In some embodiments, the first end of each movable shielding plate forms the through hole, and the second end is hinged to the insulating plate 104 via a first hinge shaft 110 ; the second end of each movable shielding plate is hinged in sequence via the connecting plate 102 .

[0062] The second end of the movable shielding plate is provided with a connecting screw 111, which is inserted through a through-hole in the two connecting plates 102. The two connecting plates 102 can rotate around the connecting screw 111. The two ends of any connecting plate 102 are rotatably inserted through the connecting screws 111 of the two adjacent movable shielding plates. The connecting plates 102 include alternating first connecting plates 1021 and second connecting plates 1022. The ends of the first connecting plates 1021 are respectively sandwiched between the corresponding movable shielding plates and the second connecting plates 1022.

[0063] For ease of operation, the auxiliary electric field diameter-changing device further includes an operating rod 113, which can be movably connected to the movable shielding plate and / or the connecting plate 102, and can drive all the movable shielding plates to move along the preset trajectory during the movement of the operating rod 113.

[0064] In some embodiments, the operating rod 113 is hinged to any of the connecting plates 102 via a second hinge shaft 115. The operating rod 113 is provided with an elongated hole for engaging with a stop screw 114. The stop screw 114 is fixed to the shield 109 and / or the plasma reaction chamber 126 of the plasma etcher.

[0065] In order to improve the integration of the auxiliary electric field diameter reducing device, all the movable shielding plates are arranged to be located on the same side of the insulating plate 104; the connecting plate 102 is located on the side of the movable shielding plate facing the insulating plate 104, and the connecting plate 102 is located on the outer periphery of the insulating plate 104, ensuring that the connecting plate 102 and the insulating plate 104 occupy the same thickness space (i.e., the circumferential space of the insulating plate 104), making the structure of the entire auxiliary electric field diameter reducing device more compact, and facilitating the assembly of the auxiliary electric field diameter reducing device between the plasma coupling coil 107 and the dielectric window 103 in the plasma etcher.

[0066] A recessed portion is provided on the side of the insulating plate 104 facing away from the movable shielding plate. The recessed portion is used to accommodate the plasma coupling coil 107 of the plasma etcher, so that the insulating plate 104 has the effect of semi-enclosing the plasma coupling coil 107, thereby improving the reliability of insulation and reducing the axial thickness dimension of the auxiliary electric field diameter reducing device (i.e., the dimension in the direction perpendicular to the plate surface of the insulating plate 104), eliminating the need to set the gap dimension between the plasma coupling coil 107 and the dielectric window 103 in the plasma etcher to be too large.

[0067] In the auxiliary electric field diameter-changing device, all the movable shielding plates have the same shape, all the first movable shielding plates 105 have the same size, and all the second movable shielding plates 106 have the same size.

[0068] The following describes the process of adjusting the through-hole size with reference to Figures 6-8:

[0069] As shown in FIG6 , when the shielding plate's through-hole size is at its minimum, the first movable shielding plate 105 and the second movable shielding plate 106 block most of the electric field, and the electric field generated by the plasma coupling coil 107 can only pass through the shielding plate's through-hole with a small inner diameter (i.e., an area with a diameter of approximately a1). Pushing the operating rod 113 in the direction c1 causes the movable shielding plate to rotate to the representative position shown in FIG7 . The inner diameter a2 of the through-hole formed by the first movable shielding plate group, which includes the first movable shielding plates 105, and the second movable shielding plate group, which includes the second movable shielding plates 106, increases, and the diameter of the electric field generated by the plasma coupling coil 107 that reaches the plasma reaction chamber 126 begins to increase. Pushing the operating rod 113 further in the direction c2 until the state shown in FIG8 . During this process, the electric field generated by the plasma coupling coil 107 gradually increases to its maximum along with the inner diameter a3 of the through-hole formed by the first movable shielding plate group and the second movable shielding plate group, and the diameter of the electric field that reaches the plasma reaction chamber 126 gradually increases to its maximum. Moving the operating rod 113 in the opposite direction can gradually reduce the inner diameter of the through hole. In this way, by adjusting the diameter of the electric field acting on the plasma reaction chamber 126, the distribution of the plasma in the plasma reaction chamber 126 acting on the wafer 103 can be adjusted, thereby adjusting the etching uniformity.

[0070] An embodiment of the present invention further provides a plasma etcher, comprising a fixedly connected shielding cover 109 and a plasma reaction chamber 126, the space enclosed by the two being divided into a first space and a second space by a dielectric window 103; a plasma coupling coil 107 is provided in the first space; the first space also comprises a gas jet 108 and an auxiliary electric field diameter reducing device as provided in the above embodiment; the gas jet 108 passes through the plasma coupling coil 107 and the dielectric window 103 and extends into the second space; the auxiliary electric field diameter reducing device is arranged between the plasma coupling coil 107 and the dielectric window 103, and the gas jet 108 passes through the through hole of the shielding plate.

[0071] The operating rod 113 of the auxiliary electric field diameter reducing device extends out of the first space to avoid operating the operating rod 113 after removing the shielding cover 109, which is convenient for users. The limiting screw 114 of the auxiliary electric field diameter reducing device is fixed to the shielding cover 109 and / or the plasma reaction chamber 126.

[0072] In some embodiments, the dielectric window 103 is provided with a protrusion on the side facing the auxiliary electric field diameter reducing device, the protrusion is circled around the outer periphery of the nozzle 108, and the protrusion is inserted into the through hole of the movable shielding plate; the insulating plate 104 of the auxiliary electric field diameter reducing device is fixed to the protrusion by fasteners, so as to facilitate the installation of the insulating plate 104.

[0073] A bias electrode 116 is disposed within the second space. A wafer placement plate 129 is positioned on the side of the bias electrode 116 facing the showerhead 108. The wafer placement plate 129 and the bias electrode 116 are connected by a connecting sleeve 127 extending around their peripheries. A recess is provided on the end surface of the connecting sleeve 127, within which a wafer positioning ring 128 is mounted for positioning a wafer 130 to be etched.

[0074] An inner liner 117 is provided in the plasma reaction chamber 126 , and the bias electrode 116 extends into the inner liner 117 .

[0075] A chamber cover 101 is provided at the open end of the plasma reaction chamber 126. The chamber cover 101 extends into the space enclosed by the shield 109 and the plasma reaction chamber 126. The dielectric window 103 is mounted on the chamber cover 101. A seal is formed between the dielectric window 103 and the chamber cover 101. A chamber cover liner 112 is secured to the chamber cover 101 to protect it.

[0076] The showerhead 108 is connected to the gas source 118 via a pipeline; the excitation source RF power supply 125 is connected to the plasma coupling coil 107 via the excitation source matching network 124; the bias RF power supply 122 is connected to the bias electrode 116 via the bias matching network 121; the plasma reaction chamber 126 is connected to the gas duct 119; and the vacuum pump 123 is connected to the gas duct 119 via the pressure control valve 120. During operation, the showerhead 108 injects gas from the gas source 118 into the plasma reaction chamber 126, generating plasma under the action of the plasma coupling coil 107. The bias electrode 116 provides a bias voltage under the action of the bias RF power supply 122 and the bias matching network 121, accelerating the plasma and causing it to bombard the wafer 130. The vacuum pump 123 extracts gas from the plasma reaction chamber 126 under the regulation of the pressure control valve 120.

[0077] The plasma etcher provided in this embodiment uses the auxiliary electric field diameter-changing device provided in the above embodiment to improve etching uniformity by changing the electric field. Of course, the plasma etcher provided in this embodiment also has other effects related to the auxiliary electric field diameter-changing device provided in the above embodiment, which will not be repeated here.

[0078] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0079] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An auxiliary electric field diameter-changing device for a plasma etcher, characterized in that: include: A shielding plate, the shielding plate can shield the electric field, and a through hole is provided in the middle of the shielding plate; The shielding plate is a whole plate, and there are multiple shielding plates, and the through holes of each shielding plate have different sizes; or The shielding plate comprises a plurality of movable shielding plates, and the movable shielding plates are connected to each other and surround the through hole with adjustable size.

2. The auxiliary electric field diameter-changing device according to claim 1, characterized in that: It also includes an insulating plate, and each of the movable shielding plates can be installed on the insulating plate so as to be movable along a preset track. During the movement along the preset track, the sizes of the through holes surrounded by all the movable shielding plates can change.

3. The auxiliary electric field diameter-changing device according to claim 2, characterized in that: The edge of each movable shielding plate overlaps with the adjacent movable shielding plates respectively.

4. The auxiliary electric field diameter-changing device according to claim 3, characterized in that: The movable shielding plate includes first movable shielding plates and second movable shielding plates arranged alternately; both side edges of any first movable shielding plate are respectively overlapped on the same side of two adjacent second movable shielding plates; and both side edges of any second movable shielding plate are respectively overlapped on the same side of two adjacent first movable shielding plates.

5. The auxiliary electric field diameter-changing device according to claim 3 or 4, characterized in that: The movable shielding plates are connected as a whole through a connecting plate, and the movable shielding plates are linked through the connecting plate.

6. The auxiliary electric field diameter-changing device according to claim 5, characterized in that: The first end of each movable shielding plate surrounds the through hole, and the second end is hinged to the insulating plate respectively; the second end of each movable shielding plate is hinged in sequence through the connecting plate.

7. The auxiliary electric field diameter-changing device according to claim 6, characterized in that: The second end of the movable shielding plate is provided with a connecting screw, the connecting screw is passed through the through holes of the two connecting plates, and the two connecting plates can rotate around the connecting screw respectively.

8. The auxiliary electric field diameter-changing device according to claim 6, characterized in that: It also includes an operating rod, which is movably connected to the movable shielding plate and / or the connecting plate, and can drive all the movable shielding plates to move along the preset track during the movement of the operating rod.

9. The auxiliary electric field diameter-changing device according to claim 8, characterized in that: The operating rod is hinged to the connecting plate; The operating rod is provided with a long hole for being inserted and matched with the limit screw.

10. The auxiliary electric field diameter-changing device according to claim 5, characterized in that: All the movable shielding plates are located on the same side of the insulating plate, and the connecting plate is located on a side of the movable shielding plates facing the insulating plate.

11. The auxiliary electric field diameter-changing device according to claim 10, characterized in that: A recessed portion is provided on one side of the insulating plate away from the movable shielding plate, for accommodating a plasma coupling coil of the plasma etcher.

12. The auxiliary electric field diameter-changing device according to claim 4, characterized in that: All the movable shielding plates have the same shape, all the first movable shielding plates have the same size, and all the second movable shielding plates have the same size.

13. A plasma etcher, characterized in that: It comprises a shielding cover and a plasma reaction chamber which are fixedly connected, and the space enclosed by the two is divided into a first space and a second space by a dielectric window; a plasma coupling coil is arranged in the first space; it also comprises a jet head and an auxiliary electric field diameter-changing device as claimed in any one of claims 1 to 12; the jet head passes through the plasma coupling coil and the dielectric window and extends into the second space; the auxiliary electric field diameter-changing device is arranged between the plasma coupling coil and the dielectric window.

14. The plasma etcher according to claim 13, characterized in that: The operating rod of the auxiliary electric field diameter-changing device extends out of the first space, and the limiting screw of the auxiliary electric field diameter-changing device is fixed to the shielding cover and / or the plasma reaction chamber.

15. The plasma etcher according to claim 13, characterized in that: A convex edge is provided on one side of the dielectric window facing the auxiliary electric field diameter-changing device, the convex edge is circled around the outer periphery of the nozzle, and the convex edge is inserted into the through hole of the movable shielding plate; the insulating plate of the auxiliary electric field diameter-changing device is fixed to the convex edge by fasteners.

16. The plasma etcher according to claim 13, characterized in that: A bias electrode is provided in the second space, and a wafer placement plate is arranged on the side of the bias electrode facing the shower head.

17. The plasma etcher according to claim 16, characterized in that: The wafer placement plate and the bias electrode are connected via a connecting sleeve sleeved on the outer periphery of the two; a sink groove is arranged on the end surface of the connecting sleeve, and a wafer positioning ring is installed in the sink groove.

18. The plasma etcher according to claim 16, characterized in that: A liner is provided in the plasma reaction chamber, and the bias electrode extends into the liner.

19. The plasma etcher according to claim 13, characterized in that: A chamber cover is provided at the open end of the plasma reaction chamber, and the chamber cover extends into the space enclosed by the shielding cover and the plasma reaction chamber; and the dielectric window is installed on the chamber cover.

20. The plasma etcher according to claim 19, characterized in that: The medium window and the cavity cover are sealed.

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