An edge ring component, a lower electrode component, a plasma processing apparatus, and a manufacturing method

Abstract

The present invention discloses an edge ring component, a lower electrode component, a plasma processing device and a preparation method. The edge ring component includes: a ring body; a first electrode disposed inside the ring body; a second electrode disposed inside the ring body, the second electrode being located below the first electrode and electrically connected thereto, the second electrode being further connected to an external first power source, and there being at least two electrical connection points between the first electrode and the second electrode. The advantages are as follows: The edge ring component improves the uniformity of the radio frequency power distribution on the first electrode through the circumferentially distributed second electrode, so as to form a more uniform electric field environment on the first electrode, which helps to improve the uniformity of the power voltage coupled by the focusing ring, and further improves the uniformity of the sheath thickness above the focusing ring, ensuring the uniformity of wafer processing.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor devices, and particularly to an edge ring assembly, a lower electrode assembly, a plasma processing apparatus, and a manufacturing method thereof. Background Art

[0002] In the manufacturing process of semiconductor devices, processes such as plasma etching, physical vapor deposition, and chemical vapor deposition are often used for microfabrication of semiconductor workpieces or wafer substrates. The steps of microfabrication manufacturing may include plasma-assisted processes, which are generally carried out in a vacuum reaction chamber. Among them, the plasma etching process in the plasma-assisted process is a key process for processing wafers into designed patterns.

[0003] With the vigorous development of semiconductor technology and the increasing integration of devices, the microscopic size of chips is getting smaller and smaller. To ensure the quality of chips, the process requirements for semiconductor processing are becoming more and more stringent. Although the plasma processing apparatus has been updated and replaced many times and its performance has been greatly improved, there are still many deficiencies in the uniformity of wafer surface treatment.

[0004] Exemplarily, in the plasma etching process, the etching rate and etching direction in the wafer edge region are different from those in its central region, resulting in lower processing uniformity in the wafer edge region and affecting the yield of wafer production. To solve this problem, a focusing ring is usually provided around the outer periphery of the wafer to adjust the electric field distribution in the vacuum reaction chamber, especially at the wafer edge. However, in practical applications, in the existing plasma processing apparatus, there are still some non-uniformities in the electric field intensity in the wafer edge region offset by the focusing ring, resulting in the processing effect in the wafer edge region not meeting the expectations. Therefore, it is necessary to improve the existing structure to meet the actual process requirements.

[0005] It can be understood that the above statements only provide background technology related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0006] Based on the foregoing technical problems, the purpose of the present invention is to provide an edge ring assembly, a lower electrode assembly, a plasma processing apparatus, and a manufacturing method thereof. The edge ring assembly is provided with a first electrode and a second electrode electrically connected through at least two electrical connection points in the ring body. The first electrode is located above the second electrode, and the second electrode is also connected to a first power source outside the ring body. The edge ring assembly improves the uniformity of the radio frequency power distribution on the first electrode through the circumferentially distributed second electrode, so as to form a more uniform electric field environment on the first electrode, which helps to improve the uniformity of the power voltage coupled by the focusing ring, and further improves the uniformity of the sheath thickness above the focusing ring, ensuring the uniformity of wafer processing.

[0007] To achieve the above object, the present invention is implemented through the following technical solutions:

[0008] An edge ring assembly, comprising:

[0009] A ring body;

[0010] A first electrode, which is arranged inside the ring body;

[0011] A second electrode, which is arranged inside the ring body, the second electrode is located below the first electrode and is electrically connected to it, the second electrode is also connected to an external first power source, and there are at least two electrical connection points between the first electrode and the second electrode.

[0012] Optionally, there are at least three electrical connection points between the first electrode and the second electrode.

[0013] Optionally, the first electrode and the second electrode are connected through at least one conductive ring structure.

[0014] Optionally, the second electrode includes at least one second sub-electrode. When there are two or more second sub-electrodes, each second sub-electrode is respectively connected to the first power source;

[0015] The second sub-electrode includes a ring electrode and / or at least two arc electrodes distributed circumferentially.

[0016] Optionally, it further includes:

[0017] A buffer electrode, which is used to connect the second electrode and the first power source.

[0018] Optionally, the second electrode is respectively connected to the first power source through at least two buffer electrodes;

[0019] And / or, there is at least one electrical connection point between the buffer electrode and each second electrode.

[0020] Optionally, it further includes:

[0021] A conductive connection head, which is used to connect the buffer electrode and the first power source.

[0022] Optionally, the conductive connection head has an electroplated conductive layer.

[0023] Optionally, it further includes:

[0024] An insulating sleeve, which is sleeved around the conductive connection head.

[0025] Optionally, it further includes:

[0026] At least one third electrode, which is disposed between the first electrode and the second electrode, and the third electrode is electrically connected to the first electrode and the second electrode respectively.

[0027] Optionally, the distance between the first electrode and the upper surface of the ring body is less than or equal to 1 mm.

[0028] Optionally, the distance between the first electrode and the second electrode in the vertical direction is less than or equal to 2 mm.

[0029] Optionally, the thickness range of the ring body is 2 mm to 10 mm.

[0030] Optionally, the ring body is made of an insulating material;

[0031] And / or, the preparation material of the first electrode includes at least one of tungsten, nickel, molybdenum, aluminum, gold and silver;

[0032] And / or, the preparation material of the second electrode includes at least one of tungsten, nickel, molybdenum, aluminum, gold and silver.

[0033] Optionally, a lower electrode assembly includes:

[0034] A base, which includes a wafer carrying surface for carrying a wafer;

[0035] A focusing ring, which is disposed around the outside of the wafer carrying surface;

[0036] The aforementioned edge ring assembly, which is disposed below the focusing ring.

[0037] Optionally, the width of the first electrode of the edge ring assembly is greater than 50% of the width of the focusing ring;

[0038] And / or, the width of the second electrode of the edge ring assembly is greater than 50% of the width of the focusing ring.

[0039] Optionally, it further includes:

[0040] A power regulating device, which is disposed between the edge ring assembly and the first power source.

[0041] Optionally, the power regulating device includes a tunable capacitor.

[0042] Optionally, a plasma processing device includes:

[0043] The aforementioned lower electrode assembly.

[0044] Optionally, it further includes:

[0045] A first power source, which is connected to the second electrode of the edge ring assembly of the lower electrode assembly.

[0046] Optionally, the first power source includes at least one of a radio frequency power source, an alternating current power source, a direct current power source, and a direct current pulsed power source.

[0047] Optionally, a method for manufacturing the foregoing edge ring assembly, the edge ring assembly further including a buffer electrode and a conductive connector, the manufacturing method including:

[0048] Processing the first electrode, the second electrode, and the buffer electrode within the ring body;

[0049] Fixing and electrically connecting the conductive connector to the buffer electrode through a conductive connection structure.

[0050] Optionally, fixing and electrically connecting the conductive connector to the buffer electrode through a conductive connection structure includes:

[0051] Covering a conductive solder layer on the lower surface of the buffer electrode;

[0052] Welding and fixing the conductive connector to the buffer electrode through the conductive solder layer.

[0053] Optionally, fixing and electrically connecting the conductive connector to the buffer electrode through a conductive connection structure includes:

[0054] Covering a conductive bonding layer on the lower surface of the buffer electrode;

[0055] Bonding and fixing the conductive connector to the buffer electrode through the conductive bonding layer.

[0056] Optionally, it further includes:

[0057] Electroplating a conductive layer on the exposed conductive connection structure and the conductive connector.

[0058] Optionally, the edge ring assembly further includes an insulating sleeve, and the manufacturing method further includes:

[0059] Sleeving the insulating sleeve on the conductive connector.

[0060] The present invention has the following advantages compared with the prior art:

[0061] In an edge ring component, a lower electrode component, a plasma processing apparatus, and a manufacturing method thereof according to the present invention, in the edge ring body, a first electrode and a second electrode electrically connected through at least two electrical connection points are provided. The first electrode is located above the second electrode, and the second electrode is further connected to a first power source outside the edge ring body. Based on the above method, the first electrode is indirectly connected to the external first power source through the circumferentially distributed second electrode. During operation, under the action of the circumferentially distributed electric field formed by the second electrode and the radio frequency power transmitted to the first electrode, a circumferentially uniform electric field environment can be formed on the first electrode. This method can reduce the problem of non-uniformity of the electric field formed in each region of the first electrode that may be caused by directly connecting the first power source to the first electrode, thereby improving the uniformity of the sheath thickness above the focusing ring and contributing to improving the uniformity and yield of wafer processing.

[0062] Furthermore, at least one third electrode may be connected in series between the first electrode and the second electrode in the edge ring component of the present invention. In this method, through the multi-layer electrodes distributed circumferentially, the uniformity of the current signal distribution on the first electrode can be further ensured to ensure the uniformity of the power coupled to the focusing ring, and thus the uniformity of the sheath thickness above it.

[0063] Furthermore, in the edge ring component of the present invention, the second electrode is electrically connected to the first power source through a buffer electrode. This method enables the second electrode to be indirectly connected to the first power source through the buffer electrode, which is convenient for processing, avoids damaging the second electrode during processing, and ensures the stability of the second electrode.

[0064] Furthermore, the edge ring component and the first power source of the present invention can form a power adjustment component to achieve independent adjustment of the focusing ring and improve the flexibility of power adjustment of the coupling to the focusing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for description will be briefly introduced below. Obviously, the drawings in the following description are an embodiment of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts:

[0066] Figure 1 is a schematic diagram of a plasma processing apparatus according to the present invention;

[0067] Figure 2 is a schematic diagram of power adjustment of an existing focusing ring;

[0068] Figure 3 is a schematic diagram of power adjustment of a focusing ring according to the present invention;

[0069] Figure 4Schematic cross-sectional view of an edge ring component of the present invention;

[0070] Figure 5 Schematic cross-sectional view of another edge ring component of the present invention;

[0071] Figure 6 Schematic cross-sectional view of yet another edge ring component of the present invention;

[0072] Figure 7 Bottom view of a ring body of the present invention;

[0073] Figure 8 Schematic cross-sectional view of the connection between a focusing ring and an edge ring component of the present invention;

[0074] Figure 9 Schematic cross-sectional view of another edge ring component of the present invention. Detailed implementation manners

[0075] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0076] It should be noted that in this article, the terms "include", "comprise", "have" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitations, the elements defined by the statement "include..." or "comprise..." do not exclude the existence of additional elements in the process, method, article or terminal device including the said elements.

[0077] It should be noted that the accompanying drawings are all in very simplified forms and use non-precise ratios, only for the purpose of facilitating and clearly assisting in explaining the objectives of the embodiments of the present invention.

[0078] Such as Figure 1As shown in the figure, it is a schematic diagram of a plasma processing device (capacitively coupled plasma processing device CCP) of the present invention. The plasma processing device includes: a vacuum reaction chamber 100, which is surrounded by a reaction chamber cavity and a cavity end cover 101. The reaction chamber cavity is usually made of a metal material and includes a cavity side wall 102 and a cavity bottom wall 103. A wafer transfer port 104 is provided on the cavity side wall 102, and the wafer transfer port 104 is used to transfer the wafer W between the inside and outside of the vacuum reaction chamber 100. Inside the vacuum reaction chamber 100, there is a lower electrode assembly 110, which is arranged at the bottom inside the vacuum reaction chamber 100. The lower electrode assembly 110 includes a base 111, and the base 111 has a wafer W bearing surface. The wafer W to be processed introduced into the vacuum reaction chamber 100 is placed on the wafer W bearing surface. The plasma processing device further includes an upper electrode assembly 120 arranged opposite to the lower electrode assembly 110. The upper electrode assembly 120 includes a gas distribution system 121, and the process gas in the gas supply device 130 is introduced into the interior of the vacuum reaction chamber 100 through the gas distribution system 121.

[0079] Furthermore, the plasma processing device further includes at least one source radio frequency power supply 140, which is connected to the upper electrode assembly 120 and / or the lower electrode assembly 110. The source radio frequency power supply 140 applies a higher-frequency source radio frequency voltage to the upper electrode assembly 120 and / or the lower electrode assembly 110 through a matching network 141 to dissociate the process gas transported into the cavity through the gas distribution system 121 into plasma, so that a plasma environment is formed between the upper electrode assembly 120 and the lower electrode assembly 110 for etching. A large number of active particles such as electrons, ions, excited atoms, molecules, and free radicals are contained in this plasma environment. The above active particles can undergo various physical and / or chemical reactions with the surface of the wafer W to be processed, causing the morphology of the wafer W to be processed to change, thereby completing the processing of the wafer W to be processed. In practical applications, the source radio frequency voltage applied by the source radio frequency power supply 140 to the cavity can be adjusted to adjust the plasma concentration in the vacuum reaction chamber 100.

[0080] To improve the processing quality of the surface of the wafer W, the lower electrode assembly 110 further includes a bias power supply, and the bias power supply is connected to the base 111 to generate a bias voltage on the wafer W, thereby accelerating the positive ions in the plasma to bombard the wafer W and improving the collimation of particle movement. As Figure 1As shown, in one embodiment, the upper edge of the base 111 has an annular step surrounding the wafer W carrying surface. Specifically, the base 111 includes a base body 1111 and an electrostatic chuck 1112. The upper edge of the base body 1111 has an annular step surrounding its central region, and the electrostatic chuck 1112 is located on the central region of the base body 1111. The upper surface of the electrostatic chuck 1112 is the wafer W carrying surface for carrying the wafer W. An adsorption electrode is provided inside the electrostatic chuck 1112 to generate an electrostatic adsorption force on the wafer W, thereby realizing the pick-up and placement of the wafer W. The base body 1111 is connected to a second power source 112, and the second power source 112 is a radio frequency power source. Of course, the second power source 112 may also be or include at least one of an alternating current power source, a direct current power source, and a direct current pulse power source. During the process, the second power source 112 applies a bias radio frequency voltage with a lower frequency to the base body 1111, thereby generating a bias voltage on the surface of the wafer W, so as to accelerate the ions in the plasma to bombard the wafer W and improve the collimation of the ion movement during the etching process.

[0081] To further improve the uniformity of the etching of the wafer W edge, the lower electrode assembly 110 further includes a focusing ring 113. The focusing ring 113 is disposed around the outside of the wafer W carrying surface of the base 111 and is located above the annular step of the base 111. The plasma processing apparatus includes a power adjustment assembly for adjusting the voltage / power coupled to the focusing ring 113 to adjust the sheath thickness above the focusing ring 113, thereby affecting the etching effect of the wafer W edge region and prolonging the life of the focusing ring. The voltage / power coupled to the focusing ring 113 is generally related to the radio frequency power coupled to the focusing ring 113 through the power adjustment assembly, and the self-bias voltage on the focusing ring 113 is related to the bias radio frequency power applied by the second power source 112.

[0082] In practical applications, the sheath thickness on the upper surface of the wafer W and the upper surface of the focusing ring 113 can be adjusted through the second power source 112 and the power adjustment assembly, so that the sheath thickness above the central region and the edge region of the wafer W is the same, that is, having the same ion incident energy and direction, thereby ensuring the uniformity of the processing of the central region and the edge region of the wafer W. However, the existing power adjustment assembly will still cause the sheath thickness above the focusing ring 113 to be uneven, resulting in an unsatisfactory processing effect in the wafer W edge region. For example, Figure 2As shown, it is a schematic diagram of an existing power regulation of a focusing ring 16. The existing power regulation component includes a ceramic ring 12 with a bias electrode 11 embedded therein and a bias power supply 13. The bias power supply 13 is a radio frequency power supply and is connected to a base 15 through a first radio frequency matcher 14. At the same time, the bias power supply 13 is directly connected to the bias electrode 11 through the first radio frequency matcher 14 and a conductive cable. When the bias power supply 13 feeds the radio frequency voltage into the bias electrode 11, the radio frequency current signal density at the connection between the bias electrode 11 and the conductive cable will be higher than the radio frequency current signal density in other areas on the bias electrode 11, and a hot spot will be formed at the connection, resulting in different powers coupled to the focusing ring 16 at the corresponding connection position, and thus resulting in different plasma sheath thicknesses at the corresponding connection position above the focusing ring 16 and its adjacent areas, that is, the sheath boundaries of the area are not at the same height, which will lead to uneven etching of the wafer edge, especially in production with high requirements for etching accuracy. On the other hand, since the connection between the bias electrode 11 and the conductive cable is fed with a high-density RF current signal for a long time, its durability is poor and its application durability is low. However, in the existing research, no research team is aware of the above technical problems, and no improvement is made on the problem. Instead, more attention is paid to how to make the overall thickness of the sheath above the focus ring 16 roughly balanced with the thickness of the sheath above the wafer.

[0083] The applicant team is aware of the above problems, and based on the above problems, the applicant team provides an edge ring assembly 114 (see Figures 3 to 9 ), the edge ring assembly 114 is provided with a first electrode 1142 and a second electrode 1143 connected by at least two electrical connection points in the ring body 1141, and the second electrode 1143 is also connected to the external first power source 115, that is, the first electrode 1142 is indirectly connected to the external first power source 115 through the second electrode 1143. During operation, under the action of the current signal transmitted by the second electrode 1143 and the circumferentially distributed electric field formed by it, the first electrode 1142 forms a uniform electric field environment. This method avoids excessive current signals at local positions on the first electrode 1142 by using the circumferentially distributed second electrodes 1143, thereby improving the uniformity of the sheath thickness above the focusing ring 113 and avoiding the phenomenon of skewness of the etching pattern in the edge area of ​​the wafer W.

[0084] Specifically, Figure 3As shown, the edge ring assembly 114 includes a ring body 1141, a first electrode 1142, and a second electrode 1143. Both the first electrode 1142 and the second electrode 1143 are disposed inside the ring body 1141. The second electrode 1143 is located below the first electrode 1142 and is electrically connected thereto. The second electrode 1143 is also connected to an external first power source 115. There are at least two electrical connection points between the first electrode 1142 and the second electrode 1143.

[0085] Based on the above, in practical applications, the current signal of the first power source 115 is first transmitted and quickly distributed on the second electrode 1143. Since the second electrode 1143 is circumferentially distributed within the ring body 1141, an annular electric field that is circumferentially distributed is quickly formed after the second electrode 1143 receives the current signal. Then, the second electrode 1143 transmits the current signal to the first electrode 1142 through each electrical connection point, so that a circumferentially uniform electric field environment is formed on the first electrode 1142. Based on this method, the intensity difference of the current signals at various positions on the first electrode 1142 can be reduced, so as to reduce the influence of the first power source 115 on the uniformity of the electric field formed at various positions of the first electrode 1142, thereby improving the spatial uniformity of the power coupled to the focusing ring 113, ensuring the uniformity of the sheath thickness above the focusing ring 113, and thus ensuring the uniformity of the etching of the edge region of the wafer W, which helps to improve the yield of the production of the wafer W. Compared with the method of directly feeding the current signal to the first electrode 1142 through a wire, the edge ring assembly 114 of the present invention ensures the uniformity of the electric field formed by the first electrode 1142 through the circumferentially distributed second electrode 1143, and has better practical applicability.

[0086] As Figure 3As shown, in one embodiment, the edge ring assembly 114 is disposed on the annular step of the base 111 and is located below the focusing ring 113. The first electrode 1142 and the second electrode 1143 of the edge ring assembly 114 are both continuous annular electrodes. There are a plurality of electrical connection points between the first electrode 1142 and the second electrode 1143, and the connection points of the electrical connection points and the second electrode 1143 connected to the first power source 115 do not coincide. The first power source 115 is a low-frequency radio frequency power source (of course, it can also be a pulsed DC power source), and it is connected to the second electrode 1143 through the second radio frequency matcher 1151. In practical applications, the first power source 115 feeds a radio frequency current signal into the second electrode 1143. After receiving the radio frequency current signal, the second electrode 1143 generates an annular radio frequency electric field environment, and then the second electrode 1143 conveys the radio frequency current signal evenly distributed in the circumferential direction to the first electrode 1142 through a plurality of electrical connection points, so that the first electrode 1142 generates a radio frequency electric field evenly distributed in the circumferential direction. Based on the above, the intensity difference of the radio frequency current signals at various positions on the first electrode 1142 can be reduced, and further the radio frequency power energy difference coupled to the focusing ring 113 can be reduced, which helps to improve the uniformity of the plasma state above the focusing ring 113.

[0087] It can be understood that the more electrical connection points between the first electrode 1142 and the second electrode 1143, the smaller the intensity difference of the current signals at various positions on the first electrode 1142, the smaller the power difference coupled from the first electrode 1142 to different regions on the focusing ring 113, and the higher the uniformity of the corresponding plasma state above it, that is, the more uniform the sheath thickness. In practical applications, at least three electrical connection points can be provided between the first electrode 1142 and the second electrode 1143 of the edge ring assembly 114, that is, they are directly electrically connected through at least three conductive wires / paths. Preferably, when there are a plurality of electrical connection points between the first electrode 1142 and the second electrode 1143, the electrical connection points are evenly distributed in the circumferential direction. On the other hand, the first electrode 1142 and the second electrode 1143 of the edge ring assembly 114 can be connected through at least one conductive ring structure. Within a certain number range, the more conductive ring structures, the smaller the intensity difference of the current signals at various positions on the first electrode 1142, the better the power uniformity coupled to the focusing ring 113, which helps to improve the uniformity of the sheath thickness above the focusing ring 113; at the same time, more conductive ring structures help to reduce the loss of the intensity of the current signal reaching the first electrode 1142. Exemplarily, in one embodiment, the first electrode 1142 and the second electrode 1143 of the edge ring assembly 114 are electrically connected through four conductive ring structures arranged in sequence in the radial direction to make the sheath above the focusing ring 113 more uniform. Preferably, the connection point of the second electrode 1143 connected to the first power source 115 does not coincide with at least some of the electrical connection points and / or conductive ring structures.

[0088] In the present invention, there is no limitation on the formation method of the electrical connection points and the conductive ring structure. In one example, two or more through holes are provided in the vertical direction between the first electrode 1142 and the second electrode 1143, and a conductive metal is filled in the through holes to form electrical connection points connecting the first electrode 1142 and the second electrode 1143. In another example, at least one annular structure is provided in the vertical direction between the first electrode 1142 and the second electrode 1143, and a metal is filled in the annular structure to form at least one electrical connection ring, i.e., the conductive ring structure.

[0089] It can be understood that the second electrode 1143 is not limited to the above structure, and in other embodiments, it may also be other structures and compositions. Optionally, the second electrode 1143 includes at least one second sub-electrode. When it has two or more second sub-electrodes, each second sub-electrode is respectively connected to the first power source 115; the second sub-electrode includes an annular electrode and / or at least two arc-shaped electrodes distributed circumferentially. Based on this method, the current signal can be distributed circumferentially in the second electrode 1143, and then a circumferential electric field environment is formed in the second electrode 1143 to improve the uniformity of the electric field formed by the first electrode 1142.

[0090] In practical applications, the ring body 1141 can be prepared from an insulating material. Exemplarily, the ring body 1141 is prepared from a ceramic material, and the ceramic material is alumina or aluminum nitride, etc. Based on the above, the first electrode 1142 and the focusing ring 113 adopt a non-direct contact method, which can not only achieve stable power coupling on the focusing ring 113, but also extend the service life of the focusing ring 113. In practical applications, the upper and lower surfaces of the ring body 1141 can be in contact with adjacent components (such as the focusing ring 113 and the base 111) through a thermally conductive and electrically conductive layer to improve the heat conduction efficiency on this path, and at the same time reduce the impedance on this path, which helps to couple the current signal to the focusing ring 113. As Figure 8 shown, in practical applications, the ring body 1141 can be connected to the focusing ring 113 by screws 11411. In order to prevent ignition between the focusing ring 113 and the base 111, a ceramic cover 11412 can be installed on the screws 11411. As Figure 9 shown, in practical applications, holes 11413 can be made on the ring body 1141 to fixedly connect it to the base 111.

[0091] Optionally, the thickness of the ring body 1141 ranges from 2 mm to 10 mm. Of course, it can also be other thickness ranges, and in practical applications, it can be set according to actual requirements. On the other hand, the preparation material of the first electrode 1142 may include at least one of tungsten, nickel, molybdenum, aluminum, gold, and silver; and / or, the preparation material of the second electrode 1143 may include at least one of tungsten, nickel, molybdenum, aluminum, gold, and silver. Of course, the first electrode 1142 and the second electrode 1143 can also be prepared using other materials or material combinations, and the present invention does not limit this.

[0092] Optionally, the distance between the first electrode 1142 and the upper surface of the ring body 1141 is less than or equal to 1 mm. Based on this method, the current signal on the first electrode 1142 can be efficiently coupled to the focusing ring 113, thereby increasing the power adjustment range of the focusing ring 113 and reducing the pressure difference between the focusing ring 113 and the wafer W. Of course, the distance between the first electrode 1142 and the upper surface of the ring body 1141 can also be other data ranges, and the present invention does not limit this. In practical applications, it can be set according to factors such as the actual expected regulation range.

[0093] On the other hand, the distance between the first electrode 1142 and the second electrode 1143 in the vertical direction is less than or equal to 2 mm. Based on this method, the first electrode 1142 and the second electrode 1143 can have a short current signal transmission distance, which helps to reduce the loss of the current signal, further ensure the uniformity of the current signal received by the first electrode 1142, and thus improve the uniformity of the power coupled to the focusing ring 113. Optionally, the width of the first electrode 1142 is greater than 50% of the ring width of the focusing ring 113; and / or, the width of the second electrode 1143 is greater than 50% of the ring width of the focusing ring 113. In practical applications, the widths of the first electrode 1142 and the second electrode 1143 are usually not more than the ring width of the focusing ring 113 for easy installation and application.

[0094] Based on the above, the edge ring assembly 114 can greatly reduce the influence of the first power source 115 on the first electrode 1142 by means of the second electrode 1143. Further, the edge ring assembly 114 further includes a buffer electrode 1144, and the buffer electrode 1144 is used to connect the second electrode 1143 to an external conductive cable, thereby realizing the electrical connection between the second electrode 1143 and the first power source 115. Based on this method, the second electrode 1143 can be indirectly connected to the first power source 115 through the buffer electrode 1144, which is convenient for processing, avoids damaging the second electrode 1143 during the processing process, and ensures the stability of the second electrode 1143.

[0095] In practical applications, the second electrode 1143 can be connected to the first power source 115 through at least two buffer electrodes 1144 respectively (in principle, one is also possible), that is, at least two metal electrode positions are arranged at the bottommost layer inside the ring body 1141. Exemplarily, in one embodiment, the second electrode 1143 is connected to an external conductive cable through three buffer electrodes 1144, and the three buffer electrodes 1144 are evenly distributed along the circumferential direction. On the other hand, there may be at least one electrical connection point between the buffer electrode 1144 and each second electrode 1143, that is, the two can be electrically connected through at least one vertical short-distance conductive path / conductive wire (see Figure 4 ), to ensure the stability of the electrical connection between the two and the efficiency of current signal transmission. The manufacturing method of the conductive path / conductive wire can be the same as that of the conductive path / conductive wire between the aforementioned first electrode 1142 and the second electrode 1143, or of course different, and the present invention does not limit this.

[0096] As Figure 4 shown, the edge ring assembly 114 further includes a conductive connector 1145, and the conductive connector 1145 is used to connect the buffer electrode 1144 to the first power source 115. In practical applications, the conductive connector 1145 is usually a metal connector. As Figure 4 shown, the conductive connector 1145 can be a female head, and a metal spring piece is arranged inside the female head to ensure the stability of its connection with the external conductive cable and the efficiency of current signal transmission, and further ensure the stability of the electrical connection with the first power source 115. As Figure 5 shown, the conductive connector 1145 can also be a male head. Further, the conductive connector 1145 has an electroplated conductive layer on its surface to stably solidify the surface of the conductive connector 1145, and further avoid the generation of particle contamination and other situations during the process. When the conductive connector 1145 is a male head, the electroplated conductive layer can further ensure the current signal transmission efficiency between it and the external conductive cable. As Figure 4 shown, an insulating sleeve 1146 is further arranged around the conductive connector 1145 to electrically isolate the conductive connector 1145 from the base 111.

[0097] On the other hand, the edge ring assembly 114 may further include at least one third electrode disposed between the first electrode 1142 and the second electrode 1143, and the third electrode is electrically connected to the first electrode 1142 and / or the second electrode 1143 (preferably, there are a plurality of electrical contact points between the first electrode 1142 and the adjacent third electrode). That is, the first electrode 1142 is the uppermost electrode inside the ring body 1141, the second electrode 1143 is the lowermost electrode, and at least one third electrode may be connected in series therebetween. Based on this method, by arranging multiple layers of electrodes distributed circumferentially below the first electrode 1142, the uniformity of the current signal distribution on the first electrode 1142 can be further ensured, so as to ensure the uniformity of the power coupled by the focusing ring 113, and further ensure the uniformity of the sheath thickness above it.

[0098] Based on the same inventive concept, the present invention also discloses a preparation method of the edge ring assembly 114, and the preparation method includes: processing the first electrode 1142, the second electrode 1143 and the buffer electrode 1144 in the ring body 1141; fixedly electrically connecting the conductive connection head 1145 and the buffer electrode 1144 through the conductive connection structure 1147 (please refer to Figure 6 ). Based on the above method, the electrical connection stability between the conductive connection head 1145 and the buffer electrode 1144 can be enhanced, and the transmission efficiency of the current signal can be ensured.

[0099] In practical applications, the conductive connection head 1145 and the buffer electrode 1144 can be electrically connected by welding or conductive adhesive bonding, that is, the conductive connection structure 1147 can be a conductive solder layer or a conductive adhesive layer. Exemplarily, in one embodiment, fixedly electrically connecting the conductive connection head 1145 and the buffer electrode 1144 through the conductive connection structure 1147 includes: covering a conductive solder layer on the lower surface of the buffer electrode 1144; welding and fixing the conductive connection head 1145 and the buffer electrode 1144 through the conductive solder layer. In actual processing, gold-tin solder can be used as the conductive solder layer, first covering it on the lower surface of the buffer electrode 1144, and then placing the metal joint in the correct position and heating to melt the solder to fix the buffer electrode 1144 and the metal joint together. In another embodiment, fixedly electrically connecting the conductive connection head 1145 and the buffer electrode 1144 through the conductive connection structure 1147 includes: covering a conductive adhesive layer on the lower surface of the buffer electrode 1144; fixedly electrically connecting the conductive connection head 1145 and the buffer electrode 1144 through the conductive adhesive layer.

[0100] Further, the preparation method further includes: electroplating a conductive layer (such as nickel) on the exposed conductive connection structure 1147, the conductive connection head 1145, and / or the buffer electrode 1144. The electroplated conductive layer can not only ensure the efficiency of current signal transmission between the conductive connection head 1145 and the external conductive cable, but also enhance the curing stability of this area. Especially in the case of connection by welding, since the solder itself is likely to contaminate the equipment, electroplating a conductive layer on the exposed metal area after welding can avoid particulate contamination of the chamber environment in this area.

[0101] Further, the preparation method further includes: sleeving an insulating sleeve 1146 on the conductive connection head 1145 to electrically isolate the conductive connection head 1145 from the base 111.

[0102] From practical experience, it is known that as the cumulative working duration increases, the focusing ring 113 will gradually be consumed, resulting in a decrease in its thickness, and further causing a decrease in the height of the plasma sheath layer above it, affecting the etching effect of the edge region of the wafer W. Based on this, in the present invention, the edge ring assembly 114 and the first power source 115 can be combined to form a power adjustment assembly with high stability, that is, a focusing ring 113 power adjustment structure. In practical applications, the first power source 115 that supplies power / voltage to the edge ring assembly 114 has two forms. As Figure 1 shown, in one way, the edge ring assembly 114 is connected to a separate first power source 115, that is, the first power source 115 adjusts the edge ring assembly 114 separately, and the first power source 115 and the second power source 112 that supplies power to the base 111 are two different power sources. During operation, by directly adjusting the power / voltage output by the first power source 115 to the edge ring assembly 114, the power voltage coupled to the focusing ring 113 is changed, thereby adjusting the plasma state and sheath thickness above it.

[0103] As Figure 3As shown, another form of the first power source 115 that supplies power / voltage to the edge ring assembly 114 is shown. In this form, the edge ring assembly 114 and the base 111 share the first power source 115. To further improve the adjustment autonomy / flexibility of the power coupled to the focusing ring 113, a power adjustment device 116 is provided between the edge ring assembly 114 and the first power source 115. The power adjustment device 116 is used to adjust the intensity of the current signal transmitted by the first power source 115 to the edge ring assembly 114. During operation, the intensity of the current signal transmitted by the first power source 115 to the edge ring assembly 114 is adjusted through the power adjustment device 116 to adjust the power / voltage coupled to the focusing ring 113, thereby adjusting the sheath uniformity above the focusing ring 113. In practical applications, the power adjustment device 116 may include a tunable capacitor. When the focusing ring 113 is consumed, the capacitance value of the tunable capacitor can be adjusted to change the power coupled to the focusing ring 113.

[0104] It should be noted that the present invention does not limit the type of the first power source 115, as long as it can make the focusing ring 113 coupled to the corresponding power through the edge ring assembly 114. Optionally, the first power source 115 includes at least one of a radio frequency power source, an alternating current power source, a direct current power source, and a direct current pulse power source.

[0105] On the other hand, the edge ring assembly 114 and / or the power adjustment assembly of the present invention can not only be used in the lower electrode assembly 110 and the plasma processing device in the above example, but in other embodiments, it can also be used in the lower electrode assembly 110 and the plasma processing device composed of other structures. For example, it can be applied to an inductively coupled plasma processing device, and the present invention does not limit this.

[0106] In one example, the base 111 of the lower electrode assembly 110 is a columnar structure, which has a wafer W bearing surface for carrying the wafer W. The base 111 is connected to a third power source, and the third power source can supply a current signal to the base 111 to form a bias voltage above the wafer W, thereby improving the collimation of plasma etching. To further improve the etching uniformity of the central region and the edge region of the wafer W, an edge adjustment device is provided outside the base 111. The edge ring assembly 114 is arranged above the edge adjustment device, and the focusing ring 113 is arranged above the edge ring assembly 114. The edge adjustment device is connected to a fourth power source, and the edge ring assembly 114 is connected to the first power source 115. During the process, the power voltage coupled to the focusing ring 113 is related to the current signals output by the fourth power source and the first power source 115. This method can improve the adjustment flexibility of the power voltage coupled to the focusing ring 113.

[0107] Based on the above manner, optionally, the third power source and the first power source 115 are the same power source or different power sources; and / or, the fourth power source and the first power source 115 are the same power source or different power sources. In practical applications, it can be set according to actual requirements.

[0108] In summary, in an edge ring component 114, a lower electrode component 110, a plasma processing apparatus, and a manufacturing method thereof according to the present invention, the edge ring component 114 is provided with a first electrode 1142 and a second electrode 1143 in a ring body 1141. The first electrode 1142 and the second electrode 1143 are electrically connected through at least two electrical connection points. The second electrode 1143 is further connected to a first power source 115 outside the ring body 1141. Based on the above manner, the first electrode 1142 is indirectly connected to the external first power source 115 through the circumferentially distributed second electrode 1143. During operation, under the action of the circumferentially distributed electric field formed in the second electrode 1143 and the radio frequency power transmitted to the first electrode 1142, a circumferentially uniform electric field environment can be formed on the first electrode 1142. This manner can reduce the problem of non-uniformity of the electric field formed in each region of the first electrode 1142 that may be caused by directly connecting the first power source 115 to the first electrode 1142, thereby improving the uniformity of the sheath thickness above the focusing ring 113 and ensuring the uniformity and yield of wafer W processing.

[0109] Further, at least one third electrode may be connected in series between the first electrode 1142 and the second electrode 1143 in the edge ring component 114 of the present invention. In this manner, through the circumferentially distributed multi-layer electrodes, the uniformity of the current signal distribution on the first electrode 1142 can be further ensured, so as to ensure the uniformity of the power coupled to the focusing ring 113, and further ensure the uniformity of the sheath thickness above it.

[0110] Further, the second electrode 1143 in the edge ring component 114 of the present invention is electrically connected to the first power source 115 through a buffer electrode 1144. This manner enables the second electrode 1143 to be indirectly connected to the first power source 115 through the buffer electrode 1144, which is convenient for processing, avoids damaging the second electrode 1143 during processing, and ensures the stability of the second electrode 1143.

[0111] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be construed as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. An edge ring assembly, characterized in that: Include: Ring body; A first electrode, which is disposed inside the ring body; The second electrode is completely arranged inside the ring body. The second electrode is located below the first electrode and is electrically connected to the first electrode. The second electrode is also connected to an external first power source to form an electric field distributed in a circumferential direction. There are at least two electrical connection points between the first electrode and the second electrode.

2. The edge ring assembly of claim 1, wherein: There are at least three electrical connection points between the first electrode and the second electrode.

3. The edge ring assembly of claim 1, wherein: The first electrode and the second electrode are connected via at least one conductive ring structure.

4. The edge ring assembly of claim 1, wherein: The second electrode comprises at least one second sub-electrode. When the second electrode comprises two or more second sub-electrodes, each second sub-electrode is respectively connected to the first power source; The second sub-electrode includes a ring electrode and / or at least two arc electrodes distributed along the circumferential direction.

5. The edge ring assembly of claim 1, wherein: Also includes: A buffer electrode is used to connect the second electrode with the first power source.

6. The edge ring assembly of claim 5, wherein: The second electrode is connected to the first power source through at least two buffer electrodes respectively; And / or, there is at least one electrical connection point between the buffer electrode and each of the second electrodes.

7. The edge ring assembly of claim 5, wherein: Also includes: A conductive connector is used to connect the buffer electrode with the first power source.

8. The edge ring assembly of claim 7, wherein: The conductive connector has an electroplated conductive layer.

9. The edge ring assembly of claim 7, wherein: Also includes: An insulating sleeve is sleeved on the outer periphery of the conductive connector.

10. The edge ring assembly of claim 1, wherein: Also includes: At least one third electrode is disposed between the first electrode and the second electrode, and the third electrode is electrically connected to the first electrode and the second electrode respectively.

11. The edge ring assembly of claim 1, wherein: A distance between the first electrode and an upper surface of the ring body is less than or equal to 1 mm.

12. The edge ring assembly of claim 1, wherein: A distance between the first electrode and the second electrode along the vertical direction is less than or equal to 2 mm.

13. The edge ring assembly of claim 1, wherein: The thickness of the ring body ranges from 2 mm to 10 mm.

14. The edge ring assembly of claim 1, wherein: The ring body is made of insulating material; And / or, the preparation material of the first electrode includes at least one of tungsten, nickel, molybdenum, aluminum, gold and silver; And / or, the material used to prepare the second electrode includes at least one of tungsten, nickel, molybdenum, aluminum, gold and silver.

15. A lower electrode assembly, characterized in that: Include: A base including a wafer carrying surface for carrying a wafer; A focusing ring, which is arranged around the outer side of the wafer carrying surface; The edge ring assembly as described in any one of claims 1 to 14 is arranged below the focus ring.

16. The lower electrode assembly according to claim 15, characterized in that The width of the first electrode of the edge ring assembly is greater than 50% of the width of the focus ring; And / or, a width of the second electrode of the edge ring assembly is greater than 50% of a width of the focus ring.

17. The lower electrode assembly according to claim 15, characterized in that Also includes: A power regulating device is disposed between the edge ring assembly and the first power source.

18. The lower electrode assembly according to claim 17, wherein: The power regulating device comprises an adjustable capacitor.

19. A plasma processing device, characterized in that: Include: A lower electrode assembly as described in any one of claims 15 to 18.

20. The plasma processing apparatus according to claim 19, wherein: Also includes: A first power source is connected to the second electrode of the edge ring assembly of the lower electrode assembly.

21. The plasma processing apparatus according to claim 20, wherein: The first power source includes at least one of a radio frequency power source, an alternating current power source, a direct current power source, and a direct current pulse power source.

22. A method for preparing an edge ring assembly according to any one of claims 1 to 14, characterized in that: The edge ring assembly further comprises a buffer electrode and a conductive connector, and the preparation method comprises: Processing the first electrode, the second electrode and the buffer electrode in the ring body; The conductive connection head is fixedly and electrically connected to the buffer electrode through a conductive connection structure.

23. The method for preparing an edge ring assembly according to claim 22, wherein: The fixed electrical connection between the conductive connector and the buffer electrode through the conductive connection structure comprises: covering the lower surface of the buffer electrode with a conductive solder layer; The conductive connector is fixed to the buffer electrode by welding through the conductive solder layer.

24. The method for preparing an edge ring assembly according to claim 22, wherein: The fixed electrical connection between the conductive connector and the buffer electrode through the conductive connection structure comprises: covering the lower surface of the buffer electrode with a conductive adhesive layer; The conductive connector is bonded and fixed to the buffer electrode through the conductive bonding layer.

25. The method for preparing an edge ring assembly according to claim 22, wherein: Also includes: A conductive layer is electroplated on the exposed conductive connection structure and the conductive connection head.

26. The method for preparing an edge ring assembly according to claim 25, wherein: The edge ring assembly further comprises an insulating sleeve, and the preparation method further comprises: The insulating sleeve is sleeved on the conductive connector.

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