Impedance adjusting device and plasma processing equipment

Abstract

The utility model provides an impedance adjusting device and plasma processing equipment, the impedance adjusting device is arranged in a vacuum reaction chamber, the reaction chamber comprises a pedestal used for placing a wafer, the reaction chamber comprises an edge electrode ring which surrounds the pedestal and is electrically insulated from the pedestal, and the bottom of the edge electrode ring is provided with a first conductive part; the edge electrode ring feed assembly is electrically connected between the edge electrode ring and the bias radio frequency power supply, and the top of the edge electrode ring feed assembly comprises a second conductive part corresponding to the first conductive part in position; and the plurality of conductive elastic devices are elastically and electrically connected between the first conductive part and the second conductive part and are used for realizing stable electric contact between the edge electrode ring and the edge electrode ring feed assembly.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor equipment, in particular to an impedance adjusting device and a plasma processing device. Background Art

[0002] In the field of semiconductor manufacturing technology, it is often necessary to perform plasma processing on a wafer to be processed in a plasma processing device. The plasma processing device has a vacuum reaction chamber, and the reaction chamber includes a pedestal for placing the wafer.

[0003] A focus ring is arranged on the outer periphery of the pedestal. The radio frequency electric field distribution at the edge of the wafer is adjusted through the focus ring, and the plasma is concentrated in the wafer area. As the focus ring is gradually eroded by the plasma, the shape of the plasma sheath at the edge of the wafer changes, and the incident direction of the ions will be inclined, so that the etching pattern in the wafer edge area cannot be formed vertically, ultimately affecting the etching result in the wafer edge area.

[0004] To solve the above problems, an edge electrode ring (located below the focus ring) is arranged on the outer periphery of the pedestal, and a bias radio frequency signal is provided to the edge electrode ring by an edge electrode ring feeding component. The edge electrode ring feeding component is electrically connected to a bias radio frequency power supply through a variable capacitor, and the potential of the edge electrode ring is adjusted by adjusting the size of the variable capacitor, thereby adjusting the plasma sheath distribution above the focus ring, compensating for the distortion of the plasma sheath caused by the loss of the focus ring, and ensuring that the etching performance in the wafer edge area is not affected by the loss of the focus ring.

[0005] A conductive pin is arranged at the top of the edge electrode ring feeding component, and the conductive pin is in single-point contact with the bottom of the edge electrode ring. Due to manufacturing tolerances, the conductive pin and the edge electrode ring are prone to poor contact, resulting in ineffective adjustment of the potential of the edge electrode ring and affecting the yield of wafer processing. Summary of the Utility Model

[0006] The purpose of the utility model is to provide an impedance adjusting device, which can ensure stable electrical contact between the edge electrode ring and the edge electrode ring feeding component, effectively adjust the potential of the edge electrode ring, and further effectively adjust the plasma sheath distribution above the wafer edge area, ensuring that the etching pattern in the wafer edge area has a good morphology.

[0007] To achieve the above purpose, the utility model provides an impedance adjusting device, which is arranged in a vacuum reaction chamber, and the reaction chamber contains a pedestal for placing a wafer, and includes:

[0008] An edge electrode ring, surrounding the pedestal and electrically insulated from the pedestal; a first conductive part is arranged at the bottom of the edge electrode ring;

[0009] An edge electrode ring feeding component, electrically connected between the edge electrode ring and a bias radio frequency power supply; the top of the edge electrode ring feeding component includes a second conductive part corresponding to the position of the first conductive part;

[0010] A plurality of conductive elastic devices, the elastic devices are elastically and electrically connected between the first conductive part and the second conductive part, and are used to achieve stable electrical contact between the edge electrode ring and the edge electrode ring feeding component.

[0011] Optionally, the first conductive part includes a plurality of first conductive holes opened on the bottom surface of the edge electrode ring; the edge electrode ring feeding component further includes a plurality of vertically arranged radio frequency guide rods, and the radio frequency guide rods are electrically connected to the bias radio frequency power supply; the second conductive part includes a plurality of conductive needles, which are respectively fixedly arranged on the tops of the plurality of radio frequency guide rods; the conductive needles are embedded in the corresponding first conductive holes, and the plurality of elastic devices are arranged between the conductive needles and the inner walls of the corresponding first conductive holes.

[0012] Optionally, the first conductive part includes a plurality of conductive needles fixedly arranged at the bottom of the edge electrode ring; the edge electrode ring feeding component includes a plurality of vertically arranged radio frequency guide rods, and the radio frequency guide rods are electrically connected to the bias radio frequency power supply; the second conductive part includes a plurality of second conductive holes, which are respectively opened on the tops of the plurality of radio frequency guide rods; the conductive needles are embedded in the corresponding second conductive holes; the plurality of elastic devices are arranged between the conductive needles and the inner walls of the corresponding second conductive holes.

[0013] Optionally, the plurality of conductive needles are uniformly distributed along the circumferential direction of the edge electrode ring.

[0014] Optionally, the plurality of elastic devices corresponding to the same conductive needle are at the same height.

[0015] Optionally, the elastic device is a reed; both ends of the reed are fixedly connected to the conductive needle, and the middle part of the reed bulges away from the central axis of the conductive needle.

[0016] Optionally, the elastic device is a reed; both ends of the reed are fixedly connected to the inner wall of the first conductive hole, and the middle part of the reed bulges towards the central axis of the first conductive hole.

[0017] Optionally, the elastic device is a reed; both ends of the reed are fixedly connected to the inner wall of the second conductive hole, and the middle part of the reed bulges towards the central axis of the second conductive hole.

[0018] Optionally, the edge electrode ring feeding component further includes at least one variable capacitor; the radio frequency guide rod is electrically connected to the bias radio frequency power supply through the variable capacitor.

[0019] Optionally, the impedance adjusting device further includes a first insulating ring; the base includes a base body and a boss provided on the top surface of the base body; the first insulating ring is provided on the top surface of the base body and surrounds the outer periphery of the boss; the edge electrode ring is placed on the top surface of the first insulating ring.

[0020] Optionally, the impedance adjusting device further includes a second insulating ring made of an elastic insulating material; the second insulating ring is sleeved on the outer side wall of the boss.

[0021] Optionally, the impedance adjusting device further includes a focusing ring, which is placed on the top surface of the edge electrode ring and surrounds the outer periphery of the wafer; the radio frequency electric field distribution at the edge of the wafer is controlled by the focusing ring.

[0022] Optionally, the elastic device is made of aluminum.

[0023] Optionally, the material of the first insulating ring includes any one of Teflon, quartz, ceramic, or a plastic part with a dielectric constant < 8.

[0024] Optionally, the material of the second insulating ring is perfluororubber.

[0025] Optionally, the interior of the base has a channel for accommodating the radio frequency guide rod, and an insulating material is filled between the radio frequency guide rod and the inner wall of the channel.

[0026] The present utility model also provides a plasma processing device, which has a vacuum reaction chamber, and a base for placing a wafer is provided in the reaction chamber. The plasma processing device includes: the impedance adjusting device as described in the present utility model.

[0027] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0028] 1) The impedance adjusting device of the present utility model can ensure stable electrical contact between the edge electrode ring and the edge electrode ring feeding component, thereby effectively adjusting the potential of the edge electrode ring, and further adjusting the plasma sheath layer distribution above the edge region of the wafer, ensuring that ions vertically bombard the edge region of the wafer, so that the etched pattern in the edge region of the wafer has a good morphology (the side wall of the etched pattern is perpendicular to the wafer surface), and improving the yield of wafer processing.

[0029] 2) The present utility model reduces the manufacturing precision and assembly difficulty of the edge electrode ring and the edge electrode feeding component. It is convenient to insert between the edge electrode ring and the edge electrode feeding component, and they always have the same potential. Even when a relatively high bias radio frequency energy is fed into the edge electrode ring, arc discharge between the edge electrode ring and the edge electrode feeding component can be effectively avoided. Description of the Drawings

[0030] To more clearly illustrate the technical solution of the present utility model, the following will briefly introduce the drawings required for description. Obviously, the drawings in the following description are an embodiment of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings:

[0031] Figure 1 It is a schematic diagram of a plasma processing device;

[0032] Figure 2 It is a schematic diagram of the distortion of the plasma sheath caused by the erosion of the focusing ring;

[0033] Figure 3 It is a schematic diagram of adjusting the plasma sheath in a direction away from the focusing ring;

[0034] Figure 4 In the first embodiment of the present utility model, it is a schematic diagram of a plasma processing device;

[0035] Figure 5 It is Figure 4 A partial enlarged schematic diagram of the dashed box;

[0036] Figure 6 In another embodiment of the present utility model, it is a schematic diagram of an elastic device connecting a first conductive part and a second conductive part;

[0037] Figure 7 In the second embodiment of the present utility model, it is a schematic diagram of an elastic device connecting a first conductive part and a second conductive part;

[0038] Figure 8 In another embodiment of the present utility model, it is a schematic diagram of an elastic device connecting a first conductive part and a second conductive part;

[0039] Figure 9 In another embodiment of the present utility model, it is a schematic diagram of a plasma processing device. Detailed implementation manners

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present utility model.

[0041] Figure 1There is shown a plasma processing apparatus 1, which is a capacitively coupled plasma (CCP) processing apparatus. As Figure 1 The shown plasma processing apparatus 1 has a vacuum reaction chamber 10, and the reaction chamber 10 includes a generally cylindrical reaction chamber sidewall 101 made of a metallic material. An opening 102 is provided on the reaction chamber sidewall 101 for accommodating a wafer W to enter and exit.

[0042] A gas showerhead 110 and a susceptor 120 for carrying the wafer W are provided in the reaction chamber 10. The gas showerhead 110 is located above the susceptor 120 and is disposed opposite to the susceptor 120. The gas showerhead 110 is connected to a gas supply device 111 for delivering a reaction gas into the reaction chamber 10 and simultaneously serves as the upper electrode of the reaction chamber 10. The susceptor 120 serves as the lower electrode of the reaction chamber 10, and a reaction region is formed between the upper electrode and the lower electrode, and high-frequency energy will be formed in this reaction region to ignite and sustain the plasma.

[0043] A source radio frequency power supply 130 (usually high-frequency, for example, with a frequency of 2 MHz to 200 MHz) applies a radio frequency signal to at least one of the upper electrode and the lower electrode ( Figure 1 the source radio frequency power supply 130 in applies a radio frequency signal to the upper electrode), thereby generating an electric field between the upper electrode and the lower electrode. This electric field accelerates a small number of electrons present inside the reaction chamber 10, causing them to collide with the gas molecules of the input reaction gas. These collisions result in the ionization of the reaction gas and the excitation of the plasma, thereby generating plasma in the reaction chamber 10. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules, and electrically neutral free radicals. The above-mentioned active particles can undergo various physical and chemical reactions with the surface of the wafer W to be processed, causing a change in the surface topography of the wafer W, that is, the etching process is completed.

[0044] An exhaust port 140 is provided at a suitable position in the reaction chamber 10, and the exhaust port 140 is connected to an external vacuum pumping device 150 (such as a vacuum pump) for exhausting reaction by-products from the reaction chamber 10.

[0045] When the plasma processes the wafer W, due to the mass difference between electrons and positive ions in the plasma, they have different moving speeds. Electrons, with smaller mass, are more easily accelerated by the electric field, so electrons have a greater speed than positive ions. Since the environment that generally confines the plasma is grounded, such as the reaction chamber wall, among the plasma and the reaction chamber wall (with a lower potential), the electrons with a fast moving speed are conducted away by the grounded reaction chamber wall, while the slow moving positive ions gather at a position at a certain distance from the reaction chamber wall and stably exist. Therefore, an electric field is generated near the reaction chamber wall. This electric field accelerates positive ions and decelerates electrons, and beats back the electrons flying towards the reaction chamber wall due to thermal motion into the plasma interior through this electric field. After the electrons and positive ions finally stabilize, a plasma sheath layer is formed.

[0046] By the same principle, a plasma sheath layer will also be formed between the plasma above the wafer and the wafer W. Through the plasma sheath layer, positive ions are accelerated downward and bombard the area to be etched on the wafer W, thereby weakening the binding force between molecules in the area to be etched. The area to be etched with weakened molecular binding force is captured by free radicals, converted into volatile gas compounds and released, thereby forming an etching pattern in the area to be etched, that is, the etching process is completed.

[0047] As Figure 1 shown, the wafer W includes a disk-shaped wafer central region Wa and an annular wafer edge region Wb (surrounding the outer periphery of the wafer central region Wa). A focusing ring 160 is usually arranged around the wafer W. The radio frequency electric field distribution at the wafer edge is controlled by the focusing ring 160, so that the plasma gathers on the wafer W and makes the plasma characteristics and ion directivity at the wafer central region Wa and the wafer edge region Wb uniform. However, as the plasma processing process is repeated, as Figure 2 shown, the erosion of the focusing ring 160 caused by ion bombardment deepens, the thickness of the focusing ring 160 thins, and the plasma sheath layer on the focusing ring 160 moves downward as the focusing ring 160 is eroded. Due to the distortion of the plasma sheath layer in the wafer edge region Wb, the ion incident direction in the wafer edge region Wb tends to tilt towards the wafer center, resulting in the tilt of the etching topography and the occurrence of the tilting phenomenon.

[0048] As Figure 1As shown, to prevent skewing, an edge electrode ring 170 (insulated from the base 120) is usually added around the base 120, and the energy of the bias RF power supply 180 (usually low frequency) is fed into the edge electrode ring 170. A variable capacitor 181 is electrically connected between the bias RF power supply 180 and the edge electrode ring 170. By adjusting the variable capacitor 181, the potential of the edge electrode ring 170 is adjusted, causing the potential at the upper end of the focusing ring to change, thereby controlling the plasma sheath layer and ion directionality at the wafer edge region Wb, and ensuring the uniformity of plasma processing in the wafer edge region.

[0049] If the variable capacitor 181 is controlled in the direction of reducing impedance, the bias RF energy transmitted to the edge electrode ring 170 increases, and the potential at the upper end of the focusing ring becomes higher, as Figure 3 shown, so as to adjust the plasma sheath layer in the direction away from the focusing ring 160. On the contrary, if the variable capacitor 181 is controlled in the direction of increasing impedance, the bias RF energy transmitted to the edge electrode ring 170 decreases, and the potential at the upper end of the focusing ring decreases, so as to adjust the plasma sheath layer in the direction close to the focusing ring 160. Therefore, by adjusting the variable capacitor 181, the plasma sheath layer distribution in the wafer edge region Wb can be controlled to prevent skewing.

[0050] Figure 1 In [description], a plurality of channels for accommodating the RF guide rods 190 are provided inside the base 120. A conductive pin 191 is provided at the top of the RF guide rod 190, and the power of the bias RF power supply 180 is fed into the edge electrode ring 170 through the RF guide rod and the conductive pin 191. To ensure good electrical contact between the conductive pin 191 and the edge electrode ring 170, high requirements are imposed on the manufacturing and assembly accuracy of the edge electrode ring 170, the RF guide rod 190, and the conductive pin 191. The bottom surface of the edge electrode ring 170 needs to have high flatness, and the top ends of the conductive pins 191 need to be located on the same horizontal plane. Due to inevitable manufacturing tolerances, poor contact is likely to occur between the conductive pin 191 and the edge electrode ring 170. When there is poor contact between the conductive pin 191 and the edge electrode ring 170, not only can the plasma sheath layer distribution in the wafer edge region Wb not be adjusted in real time, but also when the bias RF power supply 180 outputs high energy, there is a large potential difference between the conductive pin 191 and the edge electrode ring 170, and arc discharge is likely to occur, greatly affecting the safety of wafer processing.

[0051] The present invention provides an impedance adjustment device, which can ensure stable electrical contact between the edge electrode ring and the conductive pin, thereby effectively adjusting the plasma sheath layer distribution in the wafer edge region and achieving a good morphology of the etched pattern in the wafer edge region.

[0052] Embodiment 1

[0053] This embodiment provides an impedance adjustment device, as Figure 4 shown, which is arranged in a reaction chamber 20 in vacuum of a plasma processing apparatus 2, and a susceptor 220 for placing a wafer W is included in the reaction chamber 20.

[0054] As Figure 4 , Figure 5 shown, the impedance adjustment device includes: an edge electrode ring 270, an edge electrode ring feeding component, a plurality of conductive elastic devices, and a focusing ring 260.

[0055] The edge electrode ring 270 surrounds the susceptor 220 and is electrically insulated from the susceptor 220. A first conductive portion is provided at the bottom of the edge electrode ring 270. In this embodiment, as Figure 4 , Figure 5 shown, the first conductive portion includes a plurality of first conductive holes 293 formed in the bottom surface of the edge electrode ring. In a preferred embodiment, the plurality of first conductive holes 293 are evenly distributed along the circumferential direction of the edge electrode ring 270.

[0056] The impedance adjustment device in this embodiment further includes a first insulating ring 221 and a second insulating ring 222 for realizing electrical insulation between the edge electrode ring 270 and the susceptor 220. As Figure 4 shown, the susceptor 220 includes a susceptor body 220a and a boss 220b provided on the top surface of the susceptor body 220a. The first insulating ring 221 is arranged on the top surface of the susceptor body 220a and surrounds the outer periphery of the boss 220b, and the edge electrode ring 270 is placed on the top surface of the first insulating ring 221. The second insulating ring 222 is made of an elastic insulating material and is sleeved on the outer side wall of the boss 220b.

[0057] In a preferred embodiment, the material of the first insulating ring 221 includes any one of Teflon, quartz, ceramic, and plastic parts with a dielectric constant < 8. The material of the second insulating ring 222 is perfluororubber. The material of the edge electrode ring 270 is pure titanium, aluminum alloy or pure nickel, which has good plasma corrosion resistance, can reduce the generation of particulate contaminants, and is beneficial to improving the yield of wafer W processing.

[0058] The edge electrode ring feeding component is electrically connected between the edge electrode ring 270 and a bias RF power supply 280, and the top of the edge electrode ring feeding component includes a second conductive portion corresponding to the position of the first conductive portion.

[0059] As Figure 4 , Figure 5As shown, the edge electrode ring feeding assembly includes a plurality of vertically arranged RF guide rods 290, which are electrically connected to the bias RF power supply 280 and used to feed bias RF energy into the edge electrode ring 270. The interior of the base 220 has a plurality of channels respectively for accommodating the plurality of RF guide rods 290. An insulating material is filled between the RF guide rods 290 and the inner walls of the corresponding channels to prevent arc discharge between the RF guide rods 290 and the base 220.

[0060] In this embodiment, as Figure 4 , Figure 5 shown, the second conductive part includes a plurality of conductive pins 291, which are respectively fixedly arranged at the tops of the plurality of RF guide rods 290. When the RF guide rods 290 are inserted into the edge electrode ring 270, the plurality of conductive pins 291 are respectively embedded in the plurality of first conductive holes 293.

[0061] A plurality of the elastic devices are elastically and electrically connected between the first conductive part and the second conductive part and used to achieve stable electrical contact between the edge electrode ring 270 and the edge electrode ring feeding assembly. The elastic device in this embodiment is a reed 292. The material of the reed 292 can be aluminum, which has good electrical conductivity and plasma corrosion resistance. As Figure 4 , Figure 5 shown, a plurality of reeds 292 are arranged between the conductive pins 291 and the inner walls of the corresponding first conductive holes 293. Both ends of the reed 292 are fixedly connected to the conductive pins 291, and the middle part of the reed 292 bulges away from the central axis of the conductive pin and abuts against the inner wall of the first conductive hole 293.

[0062] As Figure 6 shown, in another embodiment, both ends of the reed 292 are fixedly connected to the inner wall of the first conductive hole 293, and the middle part of the reed 292 bulges towards the central axis of the first conductive hole 293 and abuts against the conductive pin 291. Thus, compared with the embodiment where both ends of the reed 292 are fixedly connected to the conductive pin 291, when both ends of the reed 292 are fixedly connected to the inner wall of the first conductive hole 293, the fixing structure is relatively stable, avoiding the knocking damage of the reed 292 caused by the insertion of the conductive pin 291 into the hole, avoiding the generation of unnecessary abrasive particles, and avoiding the risk of arc discharge.

[0063] In a preferred embodiment, a plurality of reeds 292 corresponding to the same conductive pin 291 are at the same height. Stable electrical contact between the conductive pin 291 and the inner wall of the first conductive hole 293 is achieved through the reeds 292, so the bias RF energy of the bias RF power supply 280 is stably supplied to the edge electrode ring 270.

[0064] The focusing ring 260 (e.g., made of single-crystalline silicon or silicon carbide) is placed on the top surface of the edge electrode ring 270 and surrounds the outer periphery of the wafer. The edge electrode ring 270 couples the bias RF energy of the bias RF power supply 280 to the focusing ring 260.

[0065] As Figure 4 shown, the edge electrode ring feeding assembly further includes at least one variable capacitor 281, and the variable capacitor 281 is electrically connected between the RF guide rod 290 and the bias RF power supply 280. By adjusting the variable capacitor 281, the bias RF energy coupled to the focusing ring 260 can be effectively adjusted, and then the potential at the upper end of the focusing ring 260 can be adjusted to compensate in real time for the plasma sheath distortion caused by the loss of the focusing ring 260, so as to achieve vertical bombardment of the positive ions in the plasma on the edge region Wb of the wafer, making the etching pattern of the edge region Wb of the wafer have a good morphology and improving the yield of wafer processing.

[0066] In summary, the impedance adjustment device of the present utility model can ensure stable electrical contact between the edge electrode ring 270 and the edge electrode feeding assembly, effectively adjust the bias RF energy fed into the focusing ring 260, and improve the etching quality of the edge region Wb of the wafer. It is convenient to plug and unplug between the edge electrode ring 270 and the edge electrode feeding assembly, reducing the assembly difficulty. The conductive needle 291 also does not need to contact the edge electrode ring 270, so the manufacturing precision requirements for the impedance adjustment device are relatively low. Since the edge electrode ring 270 and the conductive needle 291 always have the same potential, even when a relatively high bias RF energy is fed into the edge electrode ring 270, arc discharge between the edge electrode ring 270 and the edge electrode feeding assembly can be effectively avoided.

[0067] Embodiment 2

[0068] Different from Embodiment 1, as Figure 7 shown, the first conductive part in Embodiment 2 includes a plurality of conductive needles 291 fixedly arranged at the bottom of the edge electrode ring 270. In a preferred embodiment, the plurality of conductive needles 291 are uniformly arranged along the circumferential direction of the edge electrode ring 270. The second conductive part in Embodiment 2 includes a plurality of second conductive holes 294, which are respectively opened at the tops of the plurality of RF guide rods 290. When the RF guide rod 290 is inserted into the edge electrode ring 270, the plurality of conductive needles 291 are respectively embedded in the plurality of second conductive holes 294. The conductive needles 291 are arranged at the bottom of the edge electrode ring 270. Compared with Embodiment 1, the protruding length of the conductive needles 291 can be greatly shortened, the torque stress thereon can be reduced, and the conductive needles 291 can be avoided from moving along with the long-distance transportation of the RF guide rod 290 during the installation and disassembly process, that is, the conductive needles 291 can be in a relatively fixed installation state, avoiding problems such as wear failure and residual metal debris particles caused by long-distance transportation movement, and improving stability and reliability.

[0069] In the second embodiment, as Figure 7 shown, a plurality of reed pieces 292 are arranged between the inner wall of the conductive pin 291 and the corresponding second conductive hole 294. Both ends of the reed piece 292 are fixedly connected to the conductive pin 291, and the middle part of the reed piece 292 bulges away from the central axis of the conductive pin 291 and abuts against the inner wall of the second conductive hole 294. Thus, the fixing structure of the reed piece 292 is relatively stable, avoiding the collision and damage of the reed piece 292 during installation and disassembly, and avoiding the generation of unnecessary abrasive particles, and avoiding the risk of arc discharge.

[0070] In another embodiment, as Figure 8 shown, both ends of the reed piece 292 are fixedly connected to the inner wall of the second conductive hole 294, and the middle part of the reed piece 292 bulges towards the central axis of the second conductive hole 294 and abuts against the conductive pin 291. Thus, the reed piece 292 is hidden in the second conductive hole 294. Even if the reed piece 292 moves with the installation and disassembly of the radio frequency guide rod 290, it is protected by the second conductive hole 294 and does not contact, rub or collide with the outer hole wall, improving stability and reliability.

[0071] The stable electrical contact between the conductive pin 291 and the inner wall of the second conductive hole 294 is realized through the reed piece 292. Therefore, the bias radio frequency energy of the bias radio frequency power supply 280 is stably supplied to the edge electrode ring 270 and coupled to the focusing ring 260 by the edge electrode ring 270. Further, by adjusting the variable capacitor 281 between the radio frequency guide rod 290 and the bias radio frequency power supply 280, the bias radio frequency energy fed into the focusing ring 260 is effectively adjusted, improving the etching quality of the wafer edge region Wb.

[0072] The present invention also provides a plasma processing apparatus 2, as Figure 4 shown, which has a vacuum reaction chamber 20, and a susceptor 220 for placing a wafer W is provided in the reaction chamber 20. The plasma processing apparatus 2 further includes an impedance adjustment device as described in the present invention.

[0073] Figure 4 The plasma processing apparatus 2 in Figure 9 is a capacitively coupled plasma processing apparatus. In another embodiment, the edge impedance adjustment device of the present invention can also be applied to a plasma processing apparatus 3 as

[0074] shown. The plasma processing apparatus 3 is an inductively coupled plasma (ICP) processing apparatus, including: a reaction chamber 30, a liner 303, an insulating window 305, a plurality of inductively coupled coils 310, and an edge electrode ring feeding assembly as described in the present invention.

[0075] The inner liner 303 is disposed inside the reaction chamber 30 and is used to protect the inner wall of the reaction chamber 30 from being corroded by the plasma. The insulating window 305 is disposed at the top of the reaction chamber 30, and a reaction gas injection port 304 is provided at one end of the side wall of the reaction chamber close to the insulating window 305. The inductive coupling coil 310 is disposed above the insulating window 305 and is connected to the source radio frequency power supply 311. The inductive coupling coil 310 generates an induced magnetic field under the excitation of the source radio frequency power supply 311, and the reaction gas in the reaction chamber 30 generates plasma under the action of the induced magnetic field.

[0076] The susceptor 320 is disposed at the bottom inside the reaction chamber 30 and is used to carry the wafer W. The plasma sheath layer distribution in the wafer edge region Wb is adjusted by the edge impedance adjusting device of the present invention.

[0077] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An impedance adjustment device is disposed in a vacuum reaction chamber, and a susceptor for placing a wafer is included in the reaction chamber, and is characterized in that, Comprising: An edge electrode ring, surrounding the base and electrically insulated from the base; a first conductive portion is provided at the bottom of the edge electrode ring; An edge electrode ring feeding component, electrically connected between the edge electrode ring and a bias radio frequency power supply; the top of the edge electrode ring feeding component includes a second conductive portion corresponding to the position of the first conductive portion; A plurality of conductive elastic devices, the elastic devices being elastically electrically connected between the first conductive portion and the second conductive portion for achieving stable electrical contact between the edge electrode ring and the edge electrode ring feeding component.

2. The impedance adjusting device according to claim 1, wherein The first conductive portion includes a plurality of first conductive holes opened on the bottom surface of the edge electrode ring; the edge electrode ring feeding component further includes a plurality of vertically arranged radio frequency guide rods, the radio frequency guide rods being electrically connected to the bias radio frequency power supply; the second conductive portion includes a plurality of conductive pins respectively fixed on the tops of the plurality of radio frequency guide rods; the conductive pins are embedded in the corresponding first conductive holes, and a plurality of the elastic devices are arranged between the conductive pins and the inner walls of the corresponding first conductive holes.

3. The impedance adjustment device according to claim 1, wherein The first conductive portion includes a plurality of conductive pins fixedly arranged at the bottom of the edge electrode ring; the edge electrode ring feeding component includes a plurality of vertically arranged radio frequency guide rods, the radio frequency guide rods being electrically connected to the bias radio frequency power supply; the second conductive portion includes a plurality of second conductive holes respectively opened on the tops of the plurality of radio frequency guide rods; the conductive pins are embedded in the corresponding second conductive holes; a plurality of the elastic devices are arranged between the conductive pins and the inner walls of the corresponding second conductive holes.

4. The impedance adjustment device according to any one of claims 2 or 3, characterized in that The plurality of conductive pins are uniformly distributed along the circumferential direction of the edge electrode ring.

5. The impedance adjustment device according to any one of claims 2 or 3, characterized in that A plurality of the elastic devices corresponding to the same conductive pin are at the same height.

6. The impedance adjustment device according to any one of claims 2 or 3, characterized in that The elastic device is a reed; both ends of the reed are fixedly connected to the conductive pin, and the middle of the reed bulges away from the central axis of the conductive pin.

7. The impedance adjustment device according to claim 2, characterized in that, The elastic device is a reed; both ends of the reed are fixedly connected to the inner wall of the first conductive hole, and the middle of the reed bulges towards the central axis of the first conductive hole.

8. The impedance adjustment device according to claim 3, wherein The elastic device is a reed; both ends of the reed are fixedly connected to the inner wall of the second conductive hole, and the middle of the reed bulges towards the central axis of the second conductive hole.

9. The impedance adjustment device according to any one of claims 2 or 3, characterized in that The edge electrode ring feeding component further includes at least one variable capacitor; the radio frequency guide rod is electrically connected to the bias radio frequency power supply through the variable capacitor.

10. The impedance adjustment device according to claim 1, characterized in that, Further including a first insulating ring; the base includes a base body and a boss provided on the top surface of the base body; the first insulating ring is provided on the top surface of the base body and surrounds the outer periphery of the boss; the edge electrode ring is placed on the top surface of the first insulating ring.

11. The impedance adjusting device according to claim 10, wherein, Further including a second insulating ring, which is made of an elastic insulating material; the second insulating ring is sleeved on the outer side wall of the boss.

12. The impedance adjustment device according to claim 1, wherein Further including a focusing ring, which is placed on the top surface of the edge electrode ring and surrounds the outer periphery of the wafer; the radio frequency electric field distribution at the edge of the wafer is controlled through the focusing ring.

13. The impedance adjustment device according to claim 1, characterized in that The material of the elastic device is aluminum.

14. The impedance adjustment device according to claim 10, characterized in that, The material of the first insulating ring is any one of Teflon, quartz, ceramic or a plastic part with a dielectric constant < 8.

15. The impedance adjustment device according to claim 11, wherein The material of the second insulating ring is perfluororubber.

16. The impedance adjustment device according to any one of claims 2 or 3, characterized in that The interior of the base has a channel for accommodating the radio frequency guide rod, and an insulating material is filled between the radio frequency guide rod and the inner wall of the channel.

17. A plasma processing apparatus having a vacuum reaction chamber provided with a susceptor for placing a wafer therein, characterized in that, It includes the impedance adjusting device according to any one of claims 1 to 16.

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