Edge ring assembly, lower electrode assembly, plasma processing device and preparation method

Abstract

The invention discloses an edge ring assembly, a lower electrode assembly, a plasma processing device and a preparation method. The edge ring assembly comprises a ring body; the first electrode is arranged in the ring body; the first electrode is arranged in the ring body, the second electrode is arranged in the ring body, the second electrode is located below the first electrode and electrically connected with the first electrode, the second electrode is further connected with an external first power source, and at least two electric connection points are arranged between the first electrode and the second electrode. The edge ring assembly has the advantages that the uniformity of radio frequency power distribution on the first electrode is improved through the second electrodes distributed in the circumferential direction, so that the first electrode forms a more uniform electric field environment, the uniformity of power voltage coupled by the focusing ring is improved, the uniformity of the thickness of a sheath layer above the focusing ring is improved, and the service life of the focusing ring is prolonged. And the wafer processing uniformity is ensured.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor equipment, and in particular to an edge ring component, a lower electrode component, a plasma processing device and a preparation method. Background Art

[0002] In the manufacturing process of semiconductor devices, plasma etching, physical vapor deposition, chemical vapor deposition and other processes are often used to micro-process semiconductor process parts or wafer substrates. The micro-processing manufacturing steps 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 the key process for processing the wafer into the designed pattern.

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

[0004] For example, in a plasma etching process, the etching rate and etching direction of the edge area of ​​the wafer will be different from those of the central area, resulting in low processing uniformity in the edge area of ​​the wafer, affecting the yield rate of wafer production. In order to solve this problem, a focusing ring is usually arranged around the periphery of the wafer to adjust the electric field distribution in the vacuum reaction chamber, especially at the edge of the wafer. However, in actual applications, in existing plasma processing devices, the electric field strength of the edge area of ​​the wafer offset by the focusing ring still has some unevenness, resulting in the processing effect of the edge area of ​​the wafer failing to meet expectations. Therefore, it is necessary to improve the existing structure to meet actual process requirements.

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

[0006] Based on the above technical problems, the purpose of the present invention is to provide an edge ring assembly, a lower electrode assembly, a plasma processing device and a preparation method, wherein 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 RF power distribution on the first electrode through the second electrode distributed along the circumferential direction, so that the first electrode forms a more uniform electric field environment, which helps to improve the uniformity of the power voltage coupled by the focus ring, thereby improving the uniformity of the sheath thickness above the focus ring, and ensuring the uniformity of wafer processing.

[0007] In order to achieve the above object, the present invention is implemented by the following technical solutions: An edge ring assembly comprising: Ring body; A first electrode, which is disposed inside the ring body; The second electrode is 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. There are at least two electrical connection points between the first electrode and the second electrode.

[0008] Optionally, there are at least three electrical connection points between the first electrode and the second electrode.

[0009] Optionally, the first electrode and the second electrode are connected via at least one conductive ring structure.

[0010] Optionally, the second electrode includes at least one second sub-electrode, and when there are 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.

[0011] Optionally, also include: A buffer electrode is used to connect the second electrode with the first power source.

[0012] Optionally, 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.

[0013] Optionally, also include: A conductive connector is used to connect the buffer electrode with the first power source.

[0014] Optionally, the conductive connector has an electroplated conductive layer.

[0015] Optionally, also include: An insulating sleeve is sleeved on the outer periphery of the conductive connector.

[0016] Optionally, also include: 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.

[0017] Optionally, the distance between the first electrode and the upper surface of the ring body is less than or equal to 1 mm.

[0018] Optionally, a distance between the first electrode and the second electrode in the vertical direction is less than or equal to 2 mm.

[0019] Optionally, the thickness of the ring body ranges from 2 mm to 10 mm.

[0020] Optionally, 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.

[0021] Optionally, a lower electrode assembly comprises: 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 aforementioned edge ring assembly is arranged below the focusing ring.

[0022] Optionally, 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.

[0023] Optionally, also include: A power regulating device is disposed between the edge ring assembly and the first power source.

[0024] Optionally, the power regulating device includes an adjustable capacitor.

[0025] Optionally, a plasma processing device comprises: The aforementioned lower electrode assembly.

[0026] Optionally, also include: A first power source is connected to the second electrode of the edge ring assembly of the lower electrode assembly.

[0027] 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 pulse power source.

[0028] Optionally, a method for preparing the aforementioned edge ring assembly, wherein the edge ring assembly further comprises a buffer electrode and a conductive connector, the method comprising: 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.

[0029] Optionally, the step of fixing and electrically connecting the conductive connector to the buffer electrode through a 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.

[0030] Optionally, the step of fixing and electrically connecting the conductive connector to the buffer electrode through a 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.

[0031] Optionally, also include: A conductive layer is electroplated on the exposed conductive connection structure and the conductive connection head.

[0032] Optionally, the edge ring assembly further comprises an insulating sleeve, and the preparation method further comprises: The insulating sleeve is sleeved on the conductive connector.

[0033] Compared with the prior art, the present invention has the following advantages: In an edge ring assembly, a lower electrode assembly, a plasma processing device and a preparation method of the present invention, 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. Based on the above method, the first electrode is indirectly connected to the external first power source through the second electrode distributed along the circumferential direction, and 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, the first electrode can form an electric field environment uniformly distributed along the circumferential direction. This method can reduce the problem of uneven electric field formed in various regions of the first electrode that may be caused by the direct connection of the first power source to the first electrode, thereby improving the uniformity of the sheath thickness above the focusing ring, which helps to improve the uniformity and yield rate of wafer processing.

[0034] Furthermore, at least one third electrode can be connected in series between the first electrode and the second electrode in the edge ring assembly of the present invention. In this way, the uniformity of the current signal distribution on the first electrode can be further ensured by the multi-layer electrodes distributed along the circumferential direction, so as to ensure the uniformity of the power coupled by the focusing ring, and further ensure the uniformity of the thickness of the sheath above it.

[0035] Furthermore, the second electrode in the edge ring assembly of the present invention is electrically connected to the first power source through a buffer electrode. This method allows the second electrode to be indirectly connected to the first power source through the buffer electrode to facilitate processing, avoid damage to the second electrode during processing, and ensure the stability of the second electrode.

[0036] Furthermore, the edge ring assembly and the first power source of the present invention can form a power adjustment assembly to achieve separate adjustment of the focus ring, thereby improving the flexibility of power adjustment coupled to the focus ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the description. Obviously, the drawings described below are an embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work: Figure 1 is a schematic diagram of a plasma processing device of the present invention; Figure 2 A schematic diagram of an existing focusing ring power adjustment; Figure 3 A schematic diagram of focusing ring power adjustment according to the present invention; Figure 4 is a cross-sectional schematic diagram of an edge ring assembly of the present invention; Figure 5 is a cross-sectional schematic diagram of another edge ring assembly of the present invention; Figure 6 is a cross-sectional schematic diagram of another edge ring assembly of the present invention; Figure 7 A bottom view of a ring body of the present invention; Figure 8 A schematic cross-sectional view of a connection between a focus ring and an edge ring assembly of the present invention; Fig. 9 It is a cross-sectional schematic diagram of another edge ring assembly of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that, in this article, the terms "include", "comprises", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "includes..." or "comprising..." do not exclude the existence of other elements in the process, method, article or terminal device including the elements.

[0040] It should be noted that the drawings are all in very simplified form and use inaccurate ratios, and are only used to conveniently and clearly assist in explaining the embodiments of the present invention.

[0041] like Figure 1 , which is a schematic diagram of a plasma processing device (capacitive coupled plasma processing device CCP) of the present invention, the plasma processing device comprises: a vacuum reaction chamber 100, which is surrounded by a reaction chamber body and a chamber end cover 101, the reaction chamber body is usually made of metal material, and comprises a chamber side wall 102 and a chamber bottom wall 103. A wafer transfer port 104 is provided on the chamber side wall 102, and the wafer transfer port 104 is used to realize the transfer of wafer W between the inside and outside of the vacuum reaction chamber 100. The vacuum reaction chamber 100 comprises a lower electrode assembly 110, which is arranged at the bottom of the vacuum reaction chamber 100, and the lower electrode assembly 110 comprises a base 111, and the base 111 has a wafer W carrying surface, and the wafer W to be processed introduced into the vacuum reaction chamber 100 is placed on the wafer W carrying surface. The plasma processing apparatus further includes an upper electrode assembly 120 disposed opposite to the lower electrode assembly 110 . The upper electrode assembly 120 includes a gas distribution system 121 . The process gas in the gas supply device 130 is introduced into the vacuum reaction chamber 100 via the gas distribution system 121 .

[0042] Furthermore, the plasma processing device further comprises at least one source RF power supply 140, the source RF power supply 140 is connected to the upper electrode assembly 120 and / or the lower electrode assembly 110, and the source RF power supply 140 applies a higher frequency source RF voltage to the upper electrode assembly 120 and / or the lower electrode assembly 110 through a matching network 141, so as to dissociate the process gas transported into the chamber through the gas distribution system 121 into plasma, thereby making the upper electrode assembly 120 and the lower electrode assembly 110 a plasma environment for etching. The plasma environment contains a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals, and the above-mentioned active particles can undergo a variety of physical and / or chemical reactions with the surface of the wafer W to be processed, so that the morphology of the wafer W to be processed changes, thereby completing the processing of the wafer W to be processed. In practical applications, the source RF voltage applied by the source RF power supply 140 to the chamber can be adjusted to adjust the plasma concentration in the vacuum reaction chamber 100.

[0043] In order to improve the processing quality of the surface of the wafer W, the lower electrode assembly 110 further includes a bias power source, which 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 the particle movement. Figure 1 As shown, in one embodiment, the upper edge of the base 111 has an annular step around the wafer W bearing 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 around its central area, and the electrostatic chuck 1112 is located on the central area of ​​the base body 1111. The upper surface of the electrostatic chuck 1112 is a wafer W bearing surface for carrying wafer W. An adsorption electrode is provided in the electrostatic chuck 1112 to generate an electrostatic adsorption force on the wafer W, thereby realizing the placement and removal of the wafer W. The base body 1111 is connected to the second power source 112, and the second power source 112 is a radio frequency power source. Of course, the second power source 112 can also be or include at least one of an AC power source, a DC power source, and a DC pulse power source. During the process, the second power source 112 applies a relatively low frequency bias RF voltage to the base body 1111, thereby generating a bias voltage on the surface of the wafer W, thereby accelerating the ions in the plasma to bombard the wafer W and improving the collimation of the ions during the etching process.

[0044] In order to further improve the uniformity of the edge etching of the wafer W, the lower electrode assembly 110 further includes a focus ring 113, which is arranged around the outer side of the wafer W supporting surface of the base 111 and is located above the annular step of the base 111. The plasma processing device includes a power adjustment component, which is used to adjust the voltage / power coupled to the focus ring 113 to adjust the sheath thickness above the focus ring 113, thereby affecting the etching effect of the edge area of ​​the wafer W and extending the life of the focus ring. The voltage / power coupled to the focus ring 113 is generally related to the RF power coupled to the focus ring 113 through the power adjustment component, and the self-bias voltage on the focus ring 113 is related to the bias RF power applied by the second power source 112.

[0045] In practical applications, the sheath thickness on the upper surface of the wafer W and the upper surface of the focus ring 113 can be adjusted by the second power source 112 and the power adjustment component, so that the sheath thickness above the central area of ​​the wafer W and the edge area of ​​the wafer W are the same, that is, the ion incident energy and direction are the same, thereby ensuring the uniformity of the processing of the central area and the edge area of ​​the wafer W. However, the existing power adjustment component still causes the sheath thickness above the focus ring 113 to be uneven, resulting in unsatisfactory processing effect of the edge area of ​​the wafer W. For example, Figure 2 As 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.

[0046] 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.

[0047] Specifically, Figure 3 As shown, the edge ring assembly 114 includes a ring body 1141, a first electrode 1142, and a second electrode 1143. The first electrode 1142 and the second electrode 1143 are both disposed inside the ring body 1141, the second electrode 1143 is located below the first electrode 1142 and electrically connected thereto, the second electrode 1143 is also connected to an external first power source 115, and there are at least two electrical connection points between the first electrode 1142 and the second electrode 1143.

[0048] Based on the above, in actual application, 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 distributed circumferentially in the ring body 1141, the second electrode 1143 will quickly form a circular electric field distributed along the circumferential direction after receiving the current signal, and then the second electrode 1143 transmits the current signal to the first electrode 1142 through each electrical connection point, so that the first electrode 1142 forms an electric field environment uniformly distributed along the circumferential direction. Based on this method, the intensity difference of the current signal at each position on the first electrode 1142 can be reduced to reduce the influence of the first power source 115 on the uniformity of the electric field formed at each position of the first electrode 1142, thereby improving the spatial uniformity of the power coupled to the focus ring 113, ensuring the uniformity of the sheath thickness above the focus ring 113, thereby ensuring the uniformity of etching in the edge area of ​​the wafer W, and helping to improve the yield rate of wafer W production. 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 second electrode 1143 distributed along the circumferential direction, and has better practical applicability.

[0049] like 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 focus ring 113. The first electrode 1142 and the second electrode 1143 of the edge ring assembly 114 are both continuous annular electrodes. There are multiple electrical connection points between the first electrode 1142 and the second electrode 1143, and the electrical connection points do not overlap with the connection points where the second electrode 1143 is connected to the first power source 115. The first power source 115 is a low-frequency RF power source (of course, it can also be a pulsed DC power source), which is connected to the second electrode 1143 through a second RF matcher 1151. In practical applications, the first power source 115 feeds the RF current signal into the second electrode 1143, and the second electrode 1143 generates an annular RF electric field environment after receiving the RF current signal, and then the second electrode 1143 transmits the RF current signal uniformly distributed along the circumference to the first electrode 1142 through multiple electrical connection points, so that the first electrode 1142 generates a RF electric field uniformly distributed along the circumference. Based on the above, the intensity difference of the RF current signal at each position on the first electrode 1142 can be reduced, thereby reducing the RF power energy difference coupled to the focusing ring 113, which helps to improve the uniformity of the plasma state above the focusing ring 113.

[0050] It can be understood that the more electrical connection points there are between the first electrode 1142 and the second electrode 1143, the smaller the difference in the current signal strength at various positions on the first electrode 1142, the smaller the difference in power coupled from the first electrode 1142 to different areas 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, there can be at least three electrical connection points between the first electrode 1142 and the second electrode 1143 of the edge ring assembly 114, that is, the two are directly electrically connected through at least three conductive lines / pathways. Preferably, when there are multiple electrical connection points between the first electrode 1142 and the second electrode 1143, the electrical connection points are evenly distributed along 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 range of quantity, the more conductive ring structures there are, the smaller the difference in the current signal strength at various positions on the first electrode 1142, the better the uniformity of the power coupled to the focus ring 113, and the more uniform the sheath thickness above the focus ring 113; at the same time, more conductive ring structures help to reduce the loss of the current signal strength reaching the first electrode 1142. For example, 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 along the radial direction, so that the sheath above the focus ring 113 is more uniform. Preferably, the connection point where the second electrode 1143 is connected to the first power source 115 does not overlap with at least part of the electrical connection point and / or the conductive ring structure.

[0051] In the present invention, there is no restriction on the formation method of the electrical connection point and the conductive ring structure. In one example, two or more through holes are set in the vertical direction between the first electrode 1142 and the second electrode 1143, and conductive metal is filled in the through holes to form an electrical connection point to connect the first electrode 1142 and the second electrode 1143. In another example, at least one ring structure is set in the vertical direction between the first electrode 1142 and the second electrode 1143, and metal is filled in the ring structure to form at least one electrical connection ring, i.e., a conductive ring structure.

[0052] It is understandable that the second electrode 1143 is not limited to the above structure, and in other embodiments, it can 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 electrodes distributed along the circumferential direction. Based on this method, the current signal can be distributed circumferentially in the second electrode 1143, so that the second electrode 1143 forms a circumferential electric field environment to improve the uniformity of the electric field formed by the first electrode 1142.

[0053] In practical applications, the ring body 1141 can be made of insulating material. For example, the ring body 1141 is made of ceramic material, and the ceramic material is aluminum oxide or aluminum nitride. 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 life of the focusing ring 113. In practical applications, the upper and lower surfaces of the ring body 1141 can contact adjacent components (such as the focusing ring 113 and the base 111) through thermal and conductive layers to improve the heat conduction efficiency on the path, and at the same time reduce the impedance on the path, which helps to couple the current signal to the focusing ring 113. Figure 8 As shown, in actual application, the ring body 1141 can be connected to the focus ring 113 by screws 11411. In order to prevent ignition between the focus ring 113 and the base 111, a ceramic cover 11412 can be installed on the screws 11411. Fig. 9 As shown, in actual application, holes 11413 may be punched on the ring body 1141 to fix it to the base 111 .

[0054] Optionally, the thickness of the ring body 1141 ranges from 2 mm to 10 mm. Of course, it can also be other thickness ranges. In practical applications, it can be set according to actual needs. On the other hand, the preparation material of the first electrode 1142 can include at least one of tungsten, nickel, molybdenum, aluminum, gold and silver; and / or, the preparation material of the second electrode 1143 can 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 is not limited to this.

[0055] 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 approach, the current signal on the first electrode 1142 can be efficiently coupled to the focus ring 113, thereby increasing the power adjustment range of the focus ring 113 and reducing the pressure difference between the focus 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 is not limited to this. In actual applications, it can be set according to factors such as the actual expected control range.

[0056] 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 approach, a shorter current signal transmission distance can be provided between the first electrode 1142 and the second electrode 1143, 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 thereby 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 width of the focusing ring 113; and / or, the width of the second electrode 1143 is greater than 50% of the width of the focusing ring 113. In practical applications, the width of the first electrode 1142 and the second electrode 1143 is usually made not to exceed the width of the focusing ring 113 for ease of installation and application.

[0057] Based on the above, it can be known that 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 also includes a buffer electrode 1144, and the buffer electrode 1144 is used to connect the second electrode 1143 with 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, so as to facilitate processing, avoid damage to the second electrode 1143 during processing, and ensure the stability of the second electrode 1143.

[0058] In practical applications, the second electrode 1143 can be connected to the first power source 115 through at least two buffer electrodes 1144 (in principle, one is also acceptable), that is, at least two metal electrodes are set at the bottom layer inside the ring body 1141. For example, in one embodiment, the second electrode 1143 is connected to the external conductive cable through three buffer electrodes 1144, and the three buffer electrodes 1144 are evenly distributed along the circumference. On the other hand, there can be at least one electrical connection point between the buffer electrode 1144 and each of the second electrodes 1143, that is, the two can be electrically connected through at least one vertical short-distance conductive path / conductive line (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 line can be the same as the manufacturing method of the conductive path / conductive line between the first electrode 1142 and the second electrode 1143, of course, it can also be different, and the present invention is not limited to this.

[0059] like Figure 4 As 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 and the first power source 115. In practical applications, the conductive connector 1145 is usually a metal connector. Figure 4 As shown, the conductive connector 1145 may be a female connector, and a metal spring is disposed inside the female connector to ensure the stability of its connection with the external conductive cable and the efficiency of current signal transmission, thereby ensuring the stability of the electrical connection with the first power source 115. Figure 5 As shown, the conductive connector 1145 can also be a male connector. Furthermore, the conductive connector 1145 has an electroplated conductive layer to stabilize and solidify the surface of the conductive connector 1145, thereby avoiding particle contamination during the process. When the conductive connector 1145 is a male connector, the electroplated conductive layer can further ensure the current signal transmission efficiency between it and the external conductive cable. Figure 4 As shown, an insulating sleeve 1146 is further disposed on the periphery of the conductive connector 1145 to electrically isolate the conductive connector 1145 from the base 111 .

[0060] On the other hand, the edge ring assembly 114 may also include at least one third electrode, which is disposed between the first electrode 1142 and the second electrode 1143, and is electrically connected to the first electrode 1142 and / or the second electrode 1143 (preferably, there are multiple electrical contact points between the first electrode 1142 and the third electrode adjacent thereto). That is, the first electrode 1142 is the topmost electrode inside the ring body 1141, and the second electrode 1143 is the bottommost electrode, and at least one third electrode may be connected in series therebetween. Based on this approach, a plurality of circumferentially distributed electrodes are disposed below the first electrode 1142, which can further ensure the uniformity of the current signal distribution on the first electrode 1142, so as to ensure the uniformity of the power coupled to the focusing ring 113, and further ensure the uniformity of the thickness of the sheath layer above it.

[0061] Based on the same inventive concept, the present invention also discloses a method for preparing an edge ring assembly 114, the method comprising: processing a first electrode 1142, a second electrode 1143 and a buffer electrode 1144 in a ring body 1141; fixing and electrically connecting the conductive connector 1145 to the buffer electrode 1144 via a conductive connecting structure 1147 (see Figure 6 Based on the above method, the electrical connection stability between the conductive connector 1145 and the buffer electrode 1144 can be enhanced to ensure the transmission efficiency of the current signal.

[0062] In practical applications, the conductive connector 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. For example, in one embodiment, the conductive connector 1145 and the buffer electrode 1144 are fixedly electrically connected by the conductive connection structure 1147, including: covering the lower surface of the buffer electrode 1144 with a conductive solder layer; and fixing the conductive connector 1145 and the buffer electrode 1144 by welding with the conductive solder layer. In actual processing, gold-tin solder can be used as the conductive solder layer, which is first covered on the lower surface of the buffer electrode 1144, and then the metal joint is placed in the correct position, and the solder is heated to melt to fix the buffer electrode 1144 and the metal joint together. In another embodiment, fixing and electrically connecting the conductive connector 1145 to the buffer electrode 1144 via the conductive connection structure 1147 includes: covering the lower surface of the buffer electrode 1144 with a conductive adhesive layer; and fixing and electrically connecting the conductive connector 1145 to the buffer electrode 1144 via the conductive adhesive layer.

[0063] Furthermore, the preparation method further comprises: electroplating a conductive layer (e.g., nickel) on the exposed conductive connection structure 1147 and the conductive connector 1145 and / or the buffer electrode 1144. The electroplated conductive layer can not only ensure the efficiency of current signal transmission between the conductive connector 1145 and the external conductive cable, but also enhance the solidification stability of the area, especially in the case of welding connection, since the solder itself is easy to contaminate the equipment, electroplating a conductive layer on the exposed metal area after welding can prevent the generation of particles in the area from contaminating the cavity environment.

[0064] Furthermore, the preparation method further includes: sleeve the insulating sleeve 1146 on the conductive connector 1145 to electrically isolate the conductive connector 1145 from the base 111 .

[0065] It is known from practical experience that as the cumulative working time increases, the focus ring 113 will gradually be consumed, resulting in a decrease in its thickness, which in turn causes the height of the plasma sheath above it to become lower, affecting the etching effect of the edge area of ​​the wafer W. Based on this, in the present invention, the edge ring assembly 114 and the first power source 115 are combined to form a power regulating assembly with high stability, namely, the power regulating structure of the focus ring 113. In practical applications, the first power source 115 that provides power / voltage to the edge ring assembly 114 has two forms. Figure 1 As shown, in one embodiment, the edge ring assembly 114 is connected to a separate first power source 115, that is, the first power source 115 separately adjusts the edge ring assembly 114, and the first power source 115 and the second power source 112 that provides power to the base 111 are two different power sources. During operation, the power / voltage output by the first power source 115 to the edge ring assembly 114 is directly adjusted to change the power voltage coupled to the focus ring 113, thereby adjusting the plasma state and sheath thickness above the focus ring 113.

[0066] like Figure 3As shown, another form of the first power source 115 providing 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. In order to further improve the autonomy / flexibility of adjusting the power coupled to the focus 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 by the power adjustment device 116 to adjust the power / voltage coupled to the focus ring 113, thereby adjusting the uniformity of the sheath above the focus ring 113. In practical applications, the power adjustment device 116 may include an adjustable capacitor. When the focus ring 113 is consumed, the power coupled to the focus ring 113 may be changed by adjusting the capacitance value of the adjustable capacitor.

[0067] It should be noted that the present invention does not limit the type of the first power source 115, as long as it can couple the focus ring 113 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.

[0068] On the other hand, the edge ring assembly 114 and / or the power regulating assembly of the present invention can be used not only in the lower electrode assembly 110 and the plasma processing apparatus of the above-mentioned examples, but also in other embodiments, in the lower electrode assembly 110 and the plasma processing apparatus of other structural compositions, for example, in an inductively coupled plasma processing apparatus, and the present invention is not limited to this.

[0069] In one example, the base 111 of the lower electrode assembly 110 is a cylindrical structure having a wafer W carrying surface for carrying the wafer W. The base 111 is connected to a third power source, and the third power source can provide a current signal to the base 111 to form a bias voltage above the wafer W, thereby improving the collimation of plasma etching. In order to further improve the etching uniformity of the central area and the edge area of ​​the wafer W, an edge adjustment device is provided on the outside of the base 111, an edge ring assembly 114 is provided above the edge adjustment device, and a focusing ring 113 is provided 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 a 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 flexibility of adjusting the power voltage coupled to the focusing ring 113.

[0070] 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 needs.

[0071] In summary, in an edge ring assembly 114, a lower electrode assembly 110, a plasma processing device and a preparation method of the present invention, the edge ring assembly 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, and the second electrode 1143 is also 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 second electrode 1143 distributed in the circumferential direction, and during operation, under the action of the circumferentially distributed electric field formed by the second electrode 1143 and the radio frequency power transmitted to the first electrode 1142, the first electrode 1142 can form an electric field environment uniformly distributed in the circumferential direction. This method can reduce the non-uniformity of the electric field formed in various regions of the first electrode 1142 that may be caused by the direct connection of 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 the wafer W processing.

[0072] Furthermore, at least one third electrode can be connected in series between the first electrode 1142 and the second electrode 1143 in the edge ring assembly 114 of the present invention. In this way, the uniformity of the current signal distribution on the first electrode 1142 can be further ensured by the multi-layer electrodes distributed along the circumferential direction, so as to ensure the uniformity of the power coupled to the focusing ring 113, and further ensure the uniformity of the thickness of the sheath above it.

[0073] Furthermore, the second electrode 1143 in the edge ring assembly 114 of the present invention is electrically connected to the first power source 115 via the buffer electrode 1144. This method allows the second electrode 1143 to be indirectly connected to the first power source 115 via the buffer electrode 1144 to facilitate processing, avoid damaging the second electrode 1143 during processing, and ensure the stability of the second electrode 1143.

[0074] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. An edge ring assembly, characterized in that: Include: Ring body; A first electrode, which is disposed inside the ring body; The second electrode is 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. 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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