Upper electrode structure and semiconductor process equipment

Abstract

The invention provides an upper electrode structure and semiconductor process equipment, the upper electrode structure is used for a semiconductor process chamber, the upper electrode structure comprises a radio frequency coil and a conductive induction ring, the radio frequency coil is used for generating a first alternating magnetic field when being loaded with radio frequency, and the conductive induction ring is arranged opposite to the radio frequency coil in the axial direction of the radio frequency coil. The conductive induction ring is insulated from the radio frequency coil, and the orthographic projection of one of the radio frequency coil and the conductive induction ring on the radial plane of the other one meets the condition that at least part of one of the radio frequency coil and the conductive induction ring is located in the outer edge of the other one. According to the top electrode structure and the semiconductor process equipment provided by the invention, the improvement range of the wafer etching uniformity is relatively large, the improvement capability is relatively high, and the etching rate of the wafer edge can be obviously close to the etching rate of the wafer central region.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to an upper electrode structure and semiconductor process equipment. Background Technology

[0002] Currently, in semiconductor metal (e.g., aluminum, tungsten) etching processes (e.g., inductively coupled plasma (ICP) etching), the etching rate at the wafer edge is higher than that in the wafer center, resulting in poor etching uniformity.

[0003] Existing technology involves wrapping a conductive hot edge ring around the support component (used to support the wafer). The hot edge ring reduces the electric field at the wafer edge, thereby reducing the etching rate at the wafer edge. At the same time, the current ratio of the radio frequency coil in the upper electrode (used to feed radio frequency into the process chamber of the semiconductor device to excite the process gas in the process chamber to generate plasma) is adjusted to increase the etching rate in the central region of the wafer, thereby improving the uniformity of wafer etching.

[0004] However, existing technologies have a limited range of improvement in wafer etching uniformity and a weak ability to improve it; the etching rate at the wafer edge is still relatively high compared to the etching rate in the wafer center. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes an upper electrode structure and semiconductor process equipment, which has a large range of improvement on wafer etching uniformity and a strong improvement capability, and can make the etching rate at the edge of the wafer significantly close to the etching rate in the center region of the wafer.

[0006] To achieve the objectives of this invention, an upper electrode structure for a semiconductor process chamber is provided, comprising a radio frequency (RF) coil and a conductive sensing ring. The RF coil is used to generate a first alternating magnetic field when RF is applied. The conductive sensing ring is disposed opposite to the RF coil in the axial direction and is insulated from the RF coil. The orthogonal projection of one of the RF coil and the conductive sensing ring onto the radial plane of the other satisfies the condition that at least a portion of one of the RF coil and the conductive sensing ring is located within the outer edge of the other.

[0007] Optionally, the radio frequency coil includes one coil body or multiple coil bodies, wherein the multiple coil bodies have different diameters and are arranged in sequence around each other.

[0008] Optionally, the radio frequency coil includes a first coil body and a second coil body, the second coil body being wrapped around the first coil body, the outer diameter of the conductive sensing ring being larger than the diameter of the second coil body, and the inner diameter of the conductive sensing ring being smaller than the diameter of the second coil body but larger than the diameter of the first coil body.

[0009] Optionally, the difference between the outer diameter of the conductive sensing ring and the diameter of the second coil body is greater than or equal to 40 mm, and the difference between the inner diameter of the conductive sensing ring and the diameter of the first coil body is greater than or equal to 40 mm.

[0010] Optionally, the distance between the conductive sensing ring and the RF coil in the axial direction is in the range of 6mm-22mm.

[0011] Optionally, the upper electrode structure further includes a dielectric window, which is disposed below the radio frequency coil and is used to cover the top of the process chamber of the semiconductor process equipment. The conductive sensing ring is disposed inside the dielectric window.

[0012] Optionally, the medium window includes a top and a bottom, the bottom of the window is provided with a receiving ring groove for accommodating the conductive sensing ring, and the top of the window covers the bottom of the window.

[0013] Optionally, the conductive sensing ring has a disconnection port, and the upper electrode structure further includes an electrical switching component. The electrical switching component is electrically connected to the portions of the conductive sensing ring located on both sides of the disconnection port, and the electrical switching component is used to control the electrical conduction or disconnection of the portions of the conductive sensing ring located on both sides of the disconnection port.

[0014] Optionally, the power-on / off component includes a power-off element and two electrical connectors. The two electrical connectors are electrically connected to the portions of the conductive sensing ring located on both sides of the disconnection port, and are also electrically connected to both ends of the power-on / off element. The power-on / off element controls the portion of the conductive sensing ring located on both sides of the disconnection port to be electrically connected or disconnected by controlling the two electrical connectors to be electrically connected or disconnected.

[0015] Optionally, the two electrical connectors extend from inside the medium window to outside the medium window, and the electrical switching element is disposed outside the medium window.

[0016] Optionally, there are multiple disconnect ports and multiple power-on / off components. The multiple disconnect ports are evenly spaced in the circumferential direction of the conductive induction ring, and the multiple power-on / off components are arranged corresponding to the multiple disconnect ports.

[0017] The present invention also provides a semiconductor process apparatus, including a process chamber and an upper electrode structure as provided in the present invention, wherein the upper electrode structure is disposed on the top of the process chamber for feeding radio frequency into the process chamber to excite the process gas in the process chamber to generate plasma.

[0018] Optionally, it also includes: an impedance matching device and a control module. The RF coil is electrically connected to the RF source through the impedance matching device. The control module is used to determine whether the RF source provides RF, and when the RF source provides RF, to determine whether the impedance matching device is in a preset matching stable state. When the impedance matching device is not in the matching stable state, the conductive induction loop is electrically disconnected. When the impedance matching device is in the matching stable state, the conductive induction loop is electrically turned on.

[0019] Optionally, the conductive sensing ring has a disconnection port, and the upper electrode structure further includes an on / off component. The on / off component is electrically connected to the portions of the conductive sensing ring located on both sides of the disconnection port, and the on / off component is signal-connected to the control module. The control module is further configured to send a disconnection signal to the on / off component when the impedance matching device is not in the matched stable state, thereby controlling the portions of the conductive sensing ring located on both sides of the disconnection port to be electrically disconnected; and to send a conduction signal to the on / off component when the impedance matching device is in the matched stable state, thereby controlling the portions of the conductive sensing ring located on both sides of the disconnection port to be electrically connected.

[0020] Optionally, the impedance matching device is provided with a variable capacitor, and the matching stable state includes a ratio of the capacitance change value of the variable capacitor within a preset time to the maximum capacitance value of the variable capacitor being less than a preset rate of change.

[0021] The present invention has the following beneficial effects:

[0022] The upper electrode structure provided by this invention generates a first alternating magnetic field when the RF coil is loaded with RF. Under the influence of the first alternating magnetic field, the conductive induction ring can induce a second alternating magnetic field opposite to the direction of the first alternating magnetic field, thereby canceling the first alternating magnetic field with the help of the second alternating magnetic field. This significantly reduces the influence of the alternating magnetic field on the wafer surface and significantly reduces the eddy currents (i.e., eddy currents) induced on the wafer surface under the influence of the alternating magnetic field. Consequently, it has a large range of improvement on the uniformity of wafer etching and a strong improvement capability, making the etching rate at the edge of the wafer significantly closer to the etching rate in the center region of the wafer.

[0023] The semiconductor process equipment provided by this invention feeds radio frequency into the process chamber through the upper electrode structure provided by this invention, which excites the process gas in the process chamber to generate plasma. It has a wide range of improvement on wafer etching uniformity and a strong improvement capability, and can make the etching rate at the edge of the wafer significantly close to the etching rate in the center region of the wafer. Attached Figure Description

[0024] Figure 1 This is a three-dimensional exploded view of an upper electrode structure provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of an upper electrode structure and semiconductor process equipment provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of a conductive induction ring provided in an embodiment of the present invention;

[0027] Figure 4 This is a top view schematic diagram of an upper electrode structure provided in an embodiment of the present invention;

[0028] Figure 5 This is a three-dimensional structural diagram of another upper electrode structure provided in an embodiment of the present invention;

[0029] Figure 6 A schematic diagram of the main structure of the dielectric window and conductive induction ring of another upper electrode structure provided in an embodiment of the present invention;

[0030] Figure 7 A partial structural schematic diagram of the dielectric window and conductive induction ring of another upper electrode structure provided in an embodiment of the present invention;

[0031] Figure 8 A three-dimensional exploded view of the dielectric window and conductive induction ring of another upper electrode structure provided in an embodiment of the present invention;

[0032] Figure 9 A schematic diagram of the conductive induction ring and the current switching component of another upper electrode structure provided in an embodiment of the present invention;

[0033] Figure 10 This is a three-dimensional structural diagram of another upper electrode structure provided in an embodiment of the present invention;

[0034] Figure 11 This is a front view schematic diagram of another upper electrode structure provided in an embodiment of the present invention;

[0035] Figure 12 A simulation diagram of eddy currents on the wafer surface of the upper electrode structure provided by the relevant technology and embodiments of the present invention;

[0036] Figure 13 This is another simulation diagram of the eddy current on the wafer surface of the upper electrode structure provided by the relevant technology and the embodiments of the present invention;

[0037] Figure 14 Another simulation diagram of eddy currents on the wafer surface using related technologies;

[0038] Figure 15 Another simulation diagram of the eddy current on the wafer surface of the upper electrode structure provided in the embodiment of the present invention;

[0039] Figure 16 This is a schematic diagram of the wafer surface etching rate using the relevant technology;

[0040] Figure 17 A schematic diagram illustrating the wafer surface etching rate of the upper electrode structure provided in an embodiment of the present invention;

[0041] Figure 18 This is a schematic diagram illustrating a process for controlling the electrical disconnection or conduction of a conductive induction loop using an upper electrode structure provided in an embodiment of the present invention.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1-Upper electrode structure; 11-RF coil; 111-Second coil body; 112-First coil body; 121-Conductive induction ring; 122-Disconnection port; 123-Power switching component; 1231-Electrical connector; 1232-Power switching component; 13-Dielectric window; 131-Top of window; 132-Bottom of window; 133-Receiving ring groove; 14-Heating component; 200-Semiconductor process equipment; 201-Process chamber; 202-Carrying component; 300-Wafer. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solution of the present invention, the technical problems in the related art will first be explained.

[0045] The inventors of this invention, through research into related technologies, discovered that when an RF coil is loaded with RF power, it generates an alternating magnetic field, which is used to excite the process gas in the process chamber of a semiconductor process equipment to generate plasma. In semiconductor metal (e.g., aluminum, tungsten) etching processes (e.g., inductively coupled plasma (ICP) etching), because the wafer surface has a metal film layer (e.g., aluminum film layer, tungsten film layer), according to Faraday's law of electromagnetic induction: when the magnetic flux of a closed loop changes, a current is generated in the closed loop. Therefore, when the RF coil is loaded with RF power to generate an alternating magnetic field, eddy currents (i.e., eddy currents) will be induced on the wafer surface with the metal film layer. Under high-frequency radio frequency conditions, the metal film layer on the wafer surface is equivalent to an inductor, and the plasma sheath layer above the wafer surface is equivalent to a capacitor. The inductance on the wafer surface gradually increases from the edge to the center. The impedance at the edge of the plasma sheath layer is less than the impedance at the center of the plasma sheath layer, which results in a plasma density at the wafer edge that is greater than that at the wafer center. Consequently, the etching rate at the wafer edge is greater than that at the wafer center.

[0046] In the related technology researched by the inventors of this invention, when the radio frequency coil is loaded with a radio frequency power of 1000W, the eddy current density on the surface of the wafer with an aluminum film layer is as follows: Figures 12-14 As shown, the actual etching rate is as follows: Figure 16 As shown, Figure 12 and Figure 13 The black lines in the middle, and Figure 14 As shown by the colored lines, the eddy current density (Jsurf) at the edge of the wafer surface with an aluminum film layer is much greater than the eddy current density in the central region of the wafer surface, such as... Figure 16 As shown by the black lines, the etching rate at the edge of the wafer surface with an aluminum film layer is much greater than the etching rate in the center of the wafer. Figure 12 , Figure 13 and Figure 16 As shown, the actual etching rate of the wafer surface with an aluminum film layer has a similar trend to the eddy current density, indicating that the actual etching rate of the wafer surface with an aluminum film layer is affected by the eddy current density.

[0047] The upper electrode structure and semiconductor process equipment provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0048] like Figures 1-5 and Figures 7-11As shown, an embodiment of the present invention provides an upper electrode structure 1 for a semiconductor process chamber 201, including a radio frequency coil 11 and a conductive induction ring 121. The radio frequency coil 11 is used to generate a first alternating magnetic field when radio frequency is applied. The conductive induction ring 121 is disposed opposite to the radio frequency coil 11 in the axial direction and is insulated from the radio frequency coil 11. The orthogonal projection of one of the radio frequency coil 11 and the conductive induction ring 121 onto the radial plane of the other satisfies the following condition: at least a portion of one of the radio frequency coil 11 and the conductive induction ring 121 is located within the outer edge of the other.

[0049] For example, the orthographic projection of one of the RF coil 11 and the conductive induction ring 121 onto the radial plane of the other satisfies the following condition: at least a portion of one of the RF coil 11 and the conductive induction ring 121 is located within the outer edge of the other. This can include the following states: State 1, the orthographic projection of the RF coil 11 onto the radial plane of the conductive induction ring 121 satisfies the following condition: a portion of the RF coil 11 is located within the outer edge of the conductive induction ring 121; State 2, the orthographic projection of the RF coil 11 onto the radial plane of the conductive induction ring 121 satisfies the following condition: the entire RF coil 11 is located within the outer edge of the conductive induction ring 121; State 3, the orthographic projection of the conductive induction ring 121 onto the radial plane of the RF coil 11 satisfies the following condition: a portion of the conductive induction ring 121 is located within the outer edge of the RF coil 11; State 4, the orthographic projection of the conductive induction ring 121 onto the radial plane of the RF coil 11 satisfies the following condition: the entire conductive induction ring 121 is located within the outer edge of the RF coil 11.

[0050] The upper electrode structure 1 provided in this embodiment of the invention generates a first alternating magnetic field (such as...) when the radio frequency coil 11 is loaded with radio frequency. Figure 2 As shown by the downward arrow B), the conductive induction ring 121 can induce a second alternating magnetic field (as shown by the downward arrow B) under the influence of the first alternating magnetic field, which is opposite in direction to the first alternating magnetic field. Figure 2 As shown by the upward arrow A), the second alternating magnetic field cancels out the first alternating magnetic field, thereby significantly reducing the influence of the alternating magnetic field on the surface of wafer 300, and significantly reducing the eddy currents (i.e., eddy currents) induced on the surface of wafer 300 under the influence of the alternating magnetic field (as shown by the upward arrow A). Figure 2 As shown by the ring arrow C on the surface of wafer 300, this method can improve the etching uniformity of wafer 300 over a wide range and with strong improvement capabilities, making the etching rate at the edge of wafer 300 significantly closer to the etching rate in the central region of wafer 300.

[0051] In one embodiment of the present invention, the radio frequency coil 11 may include one coil body or multiple coil bodies, the multiple coil bodies having different diameters and being arranged in sequence around each other.

[0052] For a coil body, for example, if the outer diameter of the conductive induction ring 121 is larger than the diameter of the coil body, and the inner diameter of the conductive induction ring 121 is smaller than the diameter of the coil body, then the orthographic projection of the RF coil 11 onto the radial plane of the conductive induction ring 121 satisfies the following: the entire RF coil 11 lies within the outer edge of the conductive induction ring 121, and a portion of the conductive induction ring 121 lies within the outer edge of the RF coil 11. For another example, if the inner diameter of the conductive induction ring 121 is larger than the diameter of the coil body, then the orthographic projection of the RF coil 11 onto the radial plane of the conductive induction ring 121 satisfies the following: the entire RF coil 11 lies within the outer edge of the conductive induction ring 121. For yet another example, if the outer diameter of the conductive induction ring 121 is smaller than the diameter of the coil body, then the orthographic projection of the conductive induction ring 121 onto the radial plane of the RF coil 11 satisfies the following: the entire conductive induction ring 121 lies within the outer edge of the RF coil 11. However, for a coil body, the dimensional relationship between the conductive induction ring 121 and the radio frequency coil 11 is not limited by this. The outer diameter of the conductive induction ring 121 can be greater than, equal to or less than the diameter of the coil body, and the inner diameter of the conductive induction ring 121 can be greater than, equal to or less than the diameter of the coil body.

[0053] For multiple coil bodies, taking two coil bodies as an example, with the larger coil body surrounding the smaller coil body, and assuming the outer diameter of the conductive induction ring 121 is larger than the diameter of the larger coil body and the inner diameter of the conductive induction ring 121 is smaller than the diameter of the smaller coil body, then the orthographic projection of the RF coil 11 onto the radial plane of the conductive induction ring 121 satisfies the following: the entire RF coil 11 lies within the outer edge of the conductive induction ring 121, and the orthographic projection of the conductive induction ring 121 onto the radial plane of the RF coil 11 satisfies the following: a portion of the conductive induction ring 121 lies within the outer edge of the RF coil 11. As another example, if the inner diameter of the conductive induction ring 121 is larger than the diameter of the larger coil body, then the orthographic projection of the RF coil 11 onto the radial plane of the conductive induction ring 121 satisfies the following: the entire RF coil 11 lies within the outer edge of the conductive induction ring 121. For example, if the outer diameter of the conductive induction ring 121 is smaller than the diameter of the larger coil body, then the orthographic projection of the conductive induction ring 121 onto the radial plane of the RF coil 11 satisfies the condition that the entire conductive induction ring 121 lies within the outer edge of the RF coil 11. However, for multiple coil bodies, the dimensional relationship between the conductive induction ring 121 and the RF coil 11 is not limited by this. The outer diameter of the conductive induction ring 121 can be greater than, equal to, or less than the diameter of any one of the coil bodies, and the inner diameter of the conductive induction ring 121 can be greater than, equal to, or less than the diameter of any one of the coil bodies.

[0054] Optionally, the coil body can be a planar coil or a three-dimensional coil.

[0055] Optionally, multiple coil bodies can be arranged coaxially. That is, the axes of multiple coil bodies can be collinear.

[0056] Optionally, the conductive sensing ring 121 and the radio frequency coil 11 can be arranged coaxially. That is, the axis of the conductive sensing ring 121 and the axis of the radio frequency coil 11 can be collinear.

[0057] Optionally, the conductive sensing ring 121 can be made of metal.

[0058] Optionally, the conductive sensing ring 121 can be made of copper or aluminum.

[0059] like Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 10 and Figure 11 As shown, in one embodiment of the present invention, the radio frequency coil 11 may include a second coil body 111 and a first coil body 112. The second coil body 111 is surrounded by the first coil body 112. The outer diameter of the conductive sensing ring 121 is larger than the diameter of the second coil body 111, and the inner diameter of the conductive sensing ring 121 is smaller than the diameter of the second coil body 111 and larger than the diameter of the first coil body 112.

[0060] Radio frequency (RF) refers to alternating current (i.e., alternating current) within a certain frequency range, which changes within one cycle. In practical applications, when both the second coil body 111 and the first coil body 112 are loaded with RF, the magnetic flux of the second coil body 111 and the first coil body 112 will change due to the change in alternating current. Consequently, the second coil body 111 and the first coil body 112 will each generate an alternating magnetic field. The first alternating magnetic field includes the alternating magnetic fields generated by the second coil body 111 and the first coil body 112 respectively. By making the outer diameter of the conductive induction ring 121 larger than the diameter of the second coil body 111, and the inner diameter of the conductive induction ring 121 smaller than the diameter of the second coil body 111 but larger than the diameter of the first coil body 112, the magnetic field lines of the first alternating magnetic field can pass through the conductive induction ring 121. In other words, the conductive induction ring 121 can be affected by the first alternating magnetic field (including the alternating magnetic fields generated by the second coil body 111 and the first coil body 112 respectively). According to Faraday's law of electromagnetic induction, when the magnetic field lines of the first alternating magnetic field pass through the conductive induction ring 121, the conductive induction ring 121 will generate an induced current due to the change of the first alternating magnetic field. According to Lenz's law, the induced current will also generate a magnetic field, and the direction of its magnetic field lines is the direction that opposes the change of the first alternating magnetic field. That is to say, the direction of the magnetic field lines of the induced current generated by the conductive induction ring 121 under the influence of the first alternating magnetic field is opposite to the direction of the magnetic field lines of the first alternating magnetic field. Therefore, the magnetic field of the induced current generated by the conductive induction ring 121 under the influence of the first alternating magnetic field is mutually repulsive to the first alternating magnetic field. Thus, the conductive induction ring 121 can induce a second alternating magnetic field with the opposite direction to the first alternating magnetic field under the influence of the first alternating magnetic field. In other words, when the second coil body 111 and the first coil body 112 generate the first alternating magnetic field, the conductive induction ring 121 can induce a second alternating magnetic field with the opposite direction to the first alternating magnetic field to cancel out the first alternating magnetic field.

[0061] In practical applications, since the alternating magnetic field generated by the second coil body 111 has a greater impact on the etching rate of the wafer 300 edge than the alternating magnetic field generated by the first coil body 112, by making the outer diameter of the conductive sensing ring 121 larger than the diameter of the second coil body 111, and the inner diameter of the conductive sensing ring 121 smaller than the diameter of the second coil body 111 but larger than the diameter of the first coil body 112, the second alternating magnetic field induced by the conductive sensing ring 121 can largely offset the alternating magnetic field generated by the second coil body 111. This allows the etching rate of the wafer 300 edge to be significantly closer to the etching rate of the wafer 300 center region, and also makes the structure of the conductive sensing ring 121 simple and cost-effective, thus making the structure of the upper electrode structure 1 simple and cost-effective.

[0062] Optionally, the conductive induction ring 121, the first coil body 112, and the second coil body 111 can be arranged coaxially. That is, the axis of the conductive induction ring 121, the axis of the first coil body 112, and the axis of the second coil body 111 can be collinear.

[0063] In one embodiment of the present invention, the difference between the outer diameter of the conductive sensing ring 121 and the diameter of the second coil body 111 can be greater than or equal to 40 mm, and the difference between the inner diameter of the conductive sensing ring 121 and the diameter of the first coil body 112 can be greater than or equal to 40 mm.

[0064] In other words, the outer diameter of the conductive sensing ring 121 can be greater than or equal to 40 mm larger than the diameter of the second coil body 111, that is, the outer diameter of the conductive sensing ring 121 minus the diameter of the second coil body 111 can be ≥ 40 mm. The inner diameter of the conductive sensing ring 121 can be greater than or equal to 40 mm larger than the diameter of the first coil body 112, that is, the inner diameter of the conductive sensing ring 121 minus the diameter of the first coil body 112 can be ≥ 40 mm.

[0065] Optionally, the difference between the outer diameter of the conductive induction ring 121 and the diameter of the second coil body 111 can be 70 mm.

[0066] In other words, the outer diameter of the conductive induction ring 121 can be 70 mm larger than the diameter of the second coil body 111, that is, the outer diameter of the conductive induction ring 121 - the diameter of the second coil body 111 can be 70 mm.

[0067] Optionally, the difference between the inner diameter of the conductive induction ring 121 and the diameter of the first coil body 112 can be 150 mm.

[0068] In other words, the inner diameter of the conductive induction ring 121 can be 150mm larger than the diameter of the first coil body 112. That is, the inner diameter of the conductive induction ring 121 minus the diameter of the first coil body 112 can be 150mm.

[0069] In one embodiment of the present invention, the distance between the conductive sensing ring 121 and the radio frequency coil 11 in the axial direction can be 6mm-22mm.

[0070] Optionally, the distance between the conductive sensing ring 121 and the RF coil 11 in the axial direction can be 16 mm.

[0071] like Figures 5-8 as well as Figure 10 and Figure 11As shown, in one embodiment of the present invention, the upper electrode structure 1 may further include a dielectric window 13, which is disposed below the radio frequency coil 11 and is used to cover the top of the process chamber 201 of the semiconductor process equipment 200. The conductive sensing ring 121 is disposed inside the dielectric window 13.

[0072] Such a design is used in practical applications, such as Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 10 and Figure 11 As shown, the upper electrode structure 1 may also include a heating element 14, which is disposed between the dielectric window 13 and the radio frequency coil 11 and is insulated from the radio frequency coil 11. Since the conductive induction ring 121 needs to have a certain thickness to meet mechanical strength requirements, if the conductive induction ring 121 is disposed between the heating element 14 and the dielectric window 13, there will be a gap between the heating element 14 and the dielectric window 13 equal to at least the thickness of the conductive induction ring 121. This will affect the heating effect of the heating element 14 on the dielectric window 13, and the conductive induction ring 121 is easily deformed by the heater. If the conductive induction ring 121 is disposed between the heating element 14 and the radio frequency coil 11, the gap between the conductive induction ring 121 and the radio frequency coil 11 will be small, easily causing arcing between the conductive induction ring 121 and the radio frequency coil 11. To avoid these problems, the upper electrode structure 1 provided in this embodiment of the invention has a conductive sensing ring 121 disposed within the dielectric window 13, which can improve the stability of the upper electrode structure 1 in use. Furthermore, by disposing the conductive sensing ring 121 within the dielectric window 13, insulation between the conductive sensing ring 121 and the radio frequency coil 11 can also be achieved.

[0073] Optionally, the thickness of the conductive sensing ring 121 can be greater than or equal to 0.5 mm and less than the thickness of the dielectric window 13.

[0074] Optionally, the thickness of the conductive sensing ring 121 can be less than 40 mm.

[0075] Optionally, the medium window 13 can be made of ceramic.

[0076] In practical applications, the coefficient of thermal expansion of the ceramic medium window 13 is 6.8 × 10⁻⁶. -6 / ℃, where the temperature of the ceramic dielectric window 13 in the semiconductor process is, for example, 80℃, and the thickness of the ceramic dielectric window 13 is, for example, 25mm, then the expansion thickness of the ceramic dielectric window 13 in the semiconductor process is 13.6×10. -3The expansion thickness is small, so when processing the ceramic dielectric window 13, a thermal expansion thickness of 0.5 mm can be reserved in the internal space of the ceramic dielectric window 13 in both the horizontal and vertical directions for the conductive induction ring 121, so as to avoid the ceramic dielectric window 13 being squeezed by the conductive induction ring 121 due to thermal expansion, thereby improving the stability of the upper electrode structure 1.

[0077] like Figures 5-8 As shown, in one embodiment of the present invention, the medium window 13 may include a top window 131 and a bottom window 132. The bottom window 132 is provided with a receiving ring groove 133 for receiving a conductive sensing ring 121, and the top window 131 covers the bottom window 132.

[0078] This design allows the conductive sensing ring 121 to be positioned within the dielectric window 13.

[0079] like Figures 9-11 As shown, in one embodiment of the present invention, the conductive sensing ring 121 may have a disconnection port 122, and the upper electrode structure 1 may further include an electrical switching component 123. The electrical switching component 123 is electrically connected to the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122. The electrical switching component 123 is used to control the electrical conduction or disconnection of the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122.

[0080] This design is due to the fact that the second alternating magnetic field induced by the conductive sensing ring 121 cancels the first alternating magnetic field generated by the RF coil 11. This prevents successful ignition when the RF power loaded on the RF coil 11 is low during the ignition and start-up stage of the semiconductor process. The upper electrode structure 1 provided in this embodiment of the invention, by designing the conductive sensing ring 121 to have a disconnection port 122 and setting an on / off component 123 electrically connected to the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122, allows the on / off component 123 to control the electrical disconnection of the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122 during the ignition and start-up stage of the semiconductor process. This prevents the conductive sensing ring 121 from generating a second alternating magnetic field to cancel the first alternating magnetic field, thus avoiding any impact on ignition and start-up and ensuring smooth ignition and start-up. After ignition and stabilization, the conductive sensing ring 121 located on both sides of the disconnection port 122 can be controlled by the power switching component 123 to conduct electricity, so that the conductive sensing ring 121 can form a closed loop again. This allows the conductive sensing ring 121 to generate a second alternating magnetic field to cancel the first alternating magnetic field, thereby enabling the etching rate at the edge of the wafer 300 to be significantly closer to the etching rate in the center region of the wafer 300 in the semiconductor process.

[0081] like Figures 9-11As shown, in one embodiment of the present invention, the power-on / off component 123 may include a power-off component 1232 and two electrical connectors 1231. The two electrical connectors 1231 are electrically connected to the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122, and are also electrically connected to both ends of the power-off component 1232. The power-off component 1232 controls the electrical conduction or disconnection of the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122 by controlling the two electrical connectors 1231 to conduct or disconnect the electrical flow.

[0082] In other words, by controlling the two electrical connectors 1231 to conduct electricity, the power-on / off component 1232 can control the electrical conduction of the portion of the conductive induction ring 121 located on both sides of the disconnection port 122, which is electrically connected to the two electrical connectors 1231 in a one-to-one manner. By controlling the two electrical connectors 1231 to disconnect electricity, the power-on / off component 1232 can control the electrical disconnection of the portion of the conductive induction ring 121 located on both sides of the disconnection port 122, which is electrically connected to the two electrical connectors 1231 in a one-to-one manner.

[0083] Optionally, the power-off component 1232 may include a relay.

[0084] like Figure 10 and Figure 11 As shown, in one embodiment of the present invention, two electrical connectors 1231 can extend from inside the medium window 13 to outside the medium window 13, and the electrical switching component 1232 is disposed outside the medium window 13.

[0085] Optionally, the bottom 132 of the window may be provided with a through groove through which the power supply connector 1231 passes. The through groove is connected to the receiving ring groove 133 and the outside of the medium window 13, respectively. In this way, one end of the power connector 1231 can be electrically connected to the conductive induction ring 121 contained in the receiving ring groove 133, and can pass through the through groove to the outside of the medium window 13.

[0086] like Figures 9-11 As shown, in one embodiment of the present invention, there can be multiple disconnect ports 122 and multiple power-on / off components 123. Multiple disconnect ports 122 are evenly spaced in the circumferential direction of the conductive induction ring 121, and multiple power-on / off components 123 are correspondingly arranged with multiple disconnect ports 122.

[0087] By uniformly spacing multiple openings 122 in the circumferential direction of the conductive sensing ring 121, the structural uniformity of the conductive sensing ring 121 can be improved, thereby improving the uniformity of the etching result.

[0088] For example, such as Figures 9-11As shown, there can be four disconnect ports 122 and four power switching components 123. The four disconnect ports 122 are evenly spaced in the circumferential direction of the conductive induction ring 121. That is, there is a 90° difference between two adjacent disconnect ports 122. The four power switching components 123 are arranged corresponding to the four disconnect ports 122.

[0089] In the upper electrode structure 1 provided in this embodiment of the invention, when the radio frequency coil 11 is loaded with a radio frequency power of 1000W, the eddy current density on the surface of the wafer 300 with an aluminum film layer is as follows: Figure 12 , Figure 13 and Figure 15 As shown, the actual etching rate is as follows: Figure 17 As shown, Figure 12 , Figure 13 and Figure 15 As shown by the colored lines, the eddy current density (Jsurf) at the edge of wafer 300 with an aluminum film layer is significantly similar to the eddy current density in the central region of wafer 300. Figure 12 Different colored lines represent the differences between the outer diameter (D3) of the conductive induction ring 121 and the diameter (D1) of the second coil body 111, and the eddy current density on the surface of the wafer 300 with an aluminum film layer corresponding to the differences between the inner diameter (D4) of the conductive induction ring 121 and the diameter (D2) of the first coil body 112. Figure 13 Different colored lines represent different conductive induction rings 121 and the spacing (H) between them and the RF coil 11 along the axial direction, corresponding to the eddy current density on the surface of the wafer 300 with an aluminum film layer. Figure 15 As shown by the colored lines, the etching rate at the edge of wafer 300, which has an aluminum film layer, is significantly similar to the etching rate in the central region of wafer 300. Figure 12 , Figure 13 and Figure 17 As shown, the actual etching rate of the wafer 300 with an aluminum film layer on its surface has a similar trend to the eddy current density, indicating that the actual etching rate of the wafer 300 with an aluminum film layer on its surface is affected by the eddy current density.

[0090] In practical applications, by making the outer diameter of the conductive sensing ring 121 70 mm larger than the diameter of the second coil body 111, and the inner diameter of the conductive sensing ring 121 150 mm larger than the diameter of the first coil body 112, the eddy current on the surface of the wafer 300 can be reduced to the greatest extent. The eddy current density of the wafer 300 with an aluminum film layer on its surface can be reduced to 2.151 A / m.

[0091] This invention also provides a semiconductor process apparatus 200, including a process chamber 201 and an upper electrode structure 1 as provided in this invention embodiment. The upper electrode structure 1 is disposed on the top of the process chamber 201 and is used to feed radio frequency into the process chamber 201 to excite the process gas in the process chamber 201 to generate plasma.

[0092] The semiconductor process equipment 200 provided in this embodiment of the invention feeds radio frequency into the process chamber 201 through the upper electrode structure 1 provided in this embodiment of the invention, which excites the process gas in the process chamber 201 to generate plasma. This has a large range of improvement on the etching uniformity of the wafer 300 and a strong improvement capability, and can make the etching rate at the edge of the wafer 300 significantly close to the etching rate in the central region of the wafer 300.

[0093] In one embodiment of the present invention, the semiconductor process equipment 200 may further include an impedance matching device (not shown in the figure) and a control module (not shown in the figure). The radio frequency coil 11 is electrically connected to the radio frequency source (not shown in the figure) through the impedance matching device. The control module is used to determine whether the radio frequency source provides radio frequency, and when the radio frequency source provides radio frequency, it determines whether the impedance matching device is in a preset matching stable state. When the impedance matching device is not in a matching stable state, it electrically disconnects the conductive sensing ring 121, and when the impedance matching device is in a matching stable state, it electrically connects the conductive sensing ring 121.

[0094] In practical applications, the RF source provides RF power, which is applied to the RF coil 11 through an impedance matching device. When the RF source provides RF power and the impedance matching device is not in a stable matching state, it indicates that the semiconductor process is in the ignition stage. At this time, the control module can electrically disconnect the conductive sensing loop 121, so that the conductive sensing loop 121 is no longer a closed loop. This prevents the conductive sensing loop 121 from generating a second alternating magnetic field to cancel the first alternating magnetic field, thus not affecting the ignition and allowing the ignition to proceed smoothly. When the RF source provides RF power and the impedance matching device is in a stable matching state, it indicates that the ignition is in a stable state. At this time, the control module can electrically connect the conductive sensing loop 121, so that the conductive sensing loop 121 forms a closed loop again. This allows the conductive sensing loop 121 to generate a second alternating magnetic field to cancel the first alternating magnetic field, thereby enabling the etching rate at the edge of the wafer 300 to be significantly closer to the etching rate in the center region of the wafer 300 in the semiconductor process.

[0095] Optionally, the control module can determine whether the RF source is providing RF by detecting the RF power provided by the RF source. If the detected RF power provided by the RF source is equal to 0W, it is determined that the RF source is not providing RF. If the detected RF power provided by the RF source is greater than 0W, it is determined that the RF source is providing RF.

[0096] In one embodiment of the present invention, the conductive sensing ring 121 has a disconnection port 122, and the upper electrode structure 1 further includes an on / off component 123. The on / off component 123 is electrically connected to the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122, and the on / off component 123 is signal-connected to the control module. The control module is also used to send a disconnection signal to the on / off component 123 when the impedance matching device is not in a matched stable state, thereby controlling the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122 to be electrically disconnected through the on / off component 123. When the impedance matching device is in a matched stable state, the control module sends a conduction signal to the on / off component 123, thereby controlling the portions of the conductive sensing ring 121 located on both sides of the disconnection port 122 to be electrically connected through the on / off component 123.

[0097] In practical applications, when the RF source provides RF and the impedance matching device is not in a stable matching state, the control module can send a disconnect signal to the switching component 123. The switching component 123 then controls the partial electrical disconnection of the conductive sensing loop 121 located on both sides of the disconnection port 122, thus breaking the closed loop. When the RF source provides RF and the impedance matching device is in a stable matching state, the control module can send a conduction signal to the switching component 123. The switching component 123 then controls the partial electrical conduction of the conductive sensing loop 121 located on both sides of the disconnection port 122, allowing the conductive sensing loop 121 to form a closed loop again.

[0098] In practical applications, when the radio frequency source does not provide radio frequency, the control module can send a disconnection signal or a conduction signal to the power-on / off component 123 to control the electrical disconnection or conduction of the conductive induction ring 121 located on both sides of the disconnection port 122 through the power-on / off component 123.

[0099] In one embodiment of the present invention, the impedance matching device may be provided with a variable capacitor, and the matching stable state may include the ratio of the capacitance change value of the variable capacitor of the impedance matching device within a preset time to the maximum capacitance value of the variable capacitor being less than a preset rate of change.

[0100] Optionally, the preset time can be 1s-2s.

[0101] Optionally, the preset change rate can be 1%.

[0102] For example, the preset time is 2 seconds, the preset rate of change is less than 1%, and the maximum capacitance value of the variable capacitor of the impedance matching device is 1000pF. When the capacitance change of the variable capacitor of the impedance matching device within 2 seconds is less than 10pF (for example, the capacitance value of the variable capacitor of the impedance matching device changes between 500pF and 510pF within 2 seconds), then the ratio of the capacitance change of the variable capacitor of the impedance matching device within 2 seconds to the maximum capacitance value of the variable capacitor is less than 1% (i.e., less than 10pF / 1000pF), and it can be determined that the impedance matching device is in a stable matching state. The control module can send a conduction signal to the power-on / off component 123. In this case, when the rate of change of the ratio of the capacitance change of the variable capacitor of the impedance matching device within the preset time to the maximum capacitance value of the variable capacitor within 2 seconds is greater than 1%, it can be determined that the impedance matching device is not in a stable matching state, and the control module can send a disconnection signal to the power-on / off component 123.

[0103] like Figure 18As shown, specifically, taking the power-on / off element 1232, which includes a relay, as an example, the control module can determine whether the RF source is providing RF by detecting the RF power provided by the RF source. When the control module detects that the RF power provided by the RF source is equal to 0W, the control module can determine that the RF source is not providing RF. The control module can send a disconnection signal or a conduction signal to the power-on / off element 1232 to control the electrical disconnection or conduction of the portion of the conductive induction ring 121 located on both sides of the disconnection port 122 by controlling the power-on / off element 1232 to open or close. When the control module detects that the RF power provided by the RF source is greater than 0W, the control module can determine that the RF source is providing RF. The control module can determine whether the impedance matching device is in a stable matching state by detecting whether the ratio of the capacitance change value of the variable capacitor of the impedance matching device within a preset time to the maximum capacitance value of the variable capacitor is less than a preset change rate. Taking a preset change rate of 1% as an example, when the control module detects that the ratio of the capacitance change value of the variable capacitor of the impedance matching device within a preset time to the maximum capacitance value of the variable capacitor is less than 1%, the control module can determine that the impedance matching device is in a stable matching state. The control module can send a conduction signal to the power switch 1232 to control the conduction of the conductive induction ring 121 on both sides of the disconnection port 122 by controlling the power switch 1232 to close, so that the conductive induction ring 121 can form a closed loop, thereby enabling the conductive induction ring 121 to generate a second alternating magnetic field to cancel the first alternating magnetic field. When the control module detects that the ratio of the capacitance change of the variable capacitor of the impedance matching device within a preset time to the maximum capacitance value of the variable capacitor is greater than 1%, the control module can determine that the impedance matching device is not in a stable matching state. The control module can send a disconnect signal to the power switch 1232 to control the power disconnection of the conductive induction ring 121 on both sides of the disconnection port 122 by controlling the power switch 1232 to disconnect, so that the conductive induction ring 121 cannot form a closed loop, thereby preventing the conductive induction ring 121 from generating a second alternating magnetic field to cancel the first alternating magnetic field.

[0104] like Figure 2 As shown, optionally, the semiconductor process equipment 200 may also include a carrier component 202, which is disposed within the process chamber 201 and is used to carry the wafer 300.

[0105] In summary, the upper electrode structure 1 and semiconductor process equipment 200 provided in the embodiments of the present invention have a wide range of improvement on the etching uniformity of the wafer 300 and a strong improvement capability, which can make the etching rate at the edge of the wafer 300 significantly close to the etching rate in the central region of the wafer 300.

[0106] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An upper electrode structure for a semiconductor process chamber, characterized in that, The device includes a radio frequency (RF) coil and a conductive induction ring. The RF coil is used to generate a first alternating magnetic field when RF is applied. The conductive induction ring is disposed opposite to the RF coil in the axial direction and is insulated from the RF coil. The orthogonal projection of one of the RF coil and the conductive induction ring onto the radial plane of the other satisfies the condition that at least a portion of one of the RF coil and the conductive induction ring is located within the outer edge of the other.

2. The upper electrode structure according to claim 1, characterized in that, The radio frequency coil includes one or more coil bodies, the multiple coil bodies having different diameters and being arranged in sequence around each other.

3. The upper electrode structure according to claim 2, characterized in that, The radio frequency coil includes a first coil body and a second coil body, the second coil body being wrapped around the first coil body. The outer diameter of the conductive sensing ring is larger than the diameter of the second coil body, and the inner diameter of the conductive sensing ring is smaller than the diameter of the second coil body but larger than the diameter of the first coil body.

4. The upper electrode structure according to claim 3, characterized in that, The difference between the outer diameter of the conductive induction ring and the diameter of the second coil body is greater than or equal to 40 mm, and the difference between the inner diameter of the conductive induction ring and the diameter of the first coil body is greater than or equal to 40 mm.

5. The upper electrode structure according to claim 1, characterized in that, The distance between the conductive induction ring and the RF coil along the axial direction is in the range of 6mm-22mm.

6. The upper electrode structure according to claim 1, characterized in that, The upper electrode structure also includes a dielectric window, which is disposed below the radio frequency coil and is used to cover the top of the process chamber of the semiconductor process equipment. The conductive induction ring is disposed inside the dielectric window.

7. The upper electrode structure according to claim 6, characterized in that, The medium window includes a top and a bottom. The bottom of the window is provided with a receiving ring groove to accommodate the conductive induction ring, and the top of the window covers the bottom of the window.

8. The upper electrode structure according to claim 6, characterized in that, The conductive sensing ring has a disconnection port, and the upper electrode structure further includes an electrical switching component. The electrical switching component is electrically connected to the portions of the conductive sensing ring located on both sides of the disconnection port. The electrical switching component is used to control the electrical conduction or disconnection of the portions of the conductive sensing ring located on both sides of the disconnection port.

9. The upper electrode structure according to claim 8, characterized in that, The power-on / off component includes a power-off element and two electrical connectors. The two electrical connectors are electrically connected to the portions of the conductive sensing ring located on both sides of the disconnection port, and are also electrically connected to both ends of the power-on / off element. The power-on / off element controls the electrical conduction or disconnection of the portions of the conductive sensing ring located on both sides of the disconnection port by controlling the two electrical connectors to conduct or disconnect the electricity.

10. The upper electrode structure according to claim 9, characterized in that, Two electrical connectors extend from inside the medium window to outside the medium window, and the electrical switching element is located outside the medium window.

11. The upper electrode structure according to claim 8, characterized in that, The number of disconnect ports is multiple, the number of power switching components is multiple, the multiple disconnect ports are evenly spaced in the circumferential direction of the conductive induction ring, and the multiple power switching components are correspondingly arranged with the multiple disconnect ports.

12. A semiconductor process apparatus, characterized in that, It includes a process chamber and an upper electrode structure as described in any one of claims 1-11, wherein the upper electrode structure is disposed at the top of the process chamber for feeding radio frequency into the process chamber to excite the process gas in the process chamber to generate plasma.

13. The semiconductor process equipment according to claim 12, characterized in that, Also includes: An impedance matching device and a control module are provided. The radio frequency coil is electrically connected to the radio frequency source through the impedance matching device. The control module is used to determine whether the radio frequency source provides radio frequency, and when the radio frequency source provides radio frequency, it determines whether the impedance matching device is in a preset matching stable state. When the impedance matching device is not in the matching stable state, the conductive induction loop is electrically disconnected. When the impedance matching device is in the matching stable state, the conductive induction loop is electrically turned on.

14. The semiconductor process equipment according to claim 13, characterized in that, The conductive sensing ring has a disconnection port, and the upper electrode structure further includes an on / off component. The on / off component is electrically connected to the portions of the conductive sensing ring located on both sides of the disconnection port, and the on / off component is signal-connected to the control module. The control module is further configured to send a disconnection signal to the on / off component when the impedance matching device is not in the matched stable state, thereby controlling the portions of the conductive sensing ring located on both sides of the disconnection port to be electrically disconnected; and to send a conduction signal to the on / off component when the impedance matching device is in the matched stable state, thereby controlling the portions of the conductive sensing ring located on both sides of the disconnection port to be electrically connected.

15. The semiconductor process equipment according to claim 13, characterized in that, The impedance matching device is equipped with a variable capacitor, and the matching stable state includes a ratio of the capacitance change value of the variable capacitor within a preset time to the maximum capacitance value of the variable capacitor being less than a preset rate of change.

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