Process chamber, upper electrode device thereof, and semiconductor process equipment

Abstract

A process chamber and an upper electrode device thereof, and semiconductor process equipment. The upper electrode device (10) comprises a radio frequency coil (11) and an adjustable capacitor. The radio frequency coil (11) is wound outside a tubular shield (70) of the process chamber, and the tubular shield (70) is sleeved outside a plasma generation chamber of the process chamber. The adjustable capacitor is connected in series to the radio frequency coil (11), and the adjustable capacitor is configured to be adjusted to different capacitance values during an ignition phase and a reaction phase in the process chamber. The described solution can solve the problems of difficult ignition and plasma bombardment to dielectric windows, and can also mitigate the problem of abnormal discharge being liable to occur due to using lifting structures for radio frequency coils (11).

Description

Process chamber and upper electrode device thereof, semiconductor process equipment Technical Field

[0001] The present application belongs to the field of semiconductor equipment technology, and specifically relates to a process chamber and an upper electrode device thereof, and semiconductor process equipment. Background Art

[0002] In an inductively coupled plasma (ICP) device, an RF power supply applies RF energy to an RF coil, which then generates an alternating electromagnetic field that dissociates the process gas within the plasma chamber into plasma. During this process, the coupling of RF energy into the plasma chamber is primarily inductive, supplemented by capacitive coupling. Because of capacitive coupling, after the formation of the plasma, the electric field generated by the RF coil couples into the plasma chamber, resulting in a significant potential difference between the RF coil and the plasma. This significant potential difference accelerates the plasma within the sheath of the plasma chamber, causing it to bombard the dielectric window of the plasma chamber, thereby shortening the life of the plasma chamber. To minimize this potential difference, the electric field coupled from the RF coil to the plasma chamber must be as small as possible.

[0003] However, during the plasma generation process in the plasma generator chamber, the RF coil must couple a large electric field into the plasma generator chamber to achieve ignition. If ignition fails, plasma cannot form. However, if ignition is successful, the voltage of the RF coil must be high, which in turn creates a large potential difference between the RF coil and the plasma, resulting in a large electric field that drives the plasma to bombard the dielectric window. Therefore, solving the ignition problem and reducing the plasma bombardment of the plasma generator chamber in the related art have become a difficult contradiction to reconcile. Overcoming this contradiction is an important issue that needs to be addressed urgently by those skilled in the relevant art. Summary of the Invention

[0004] The present application discloses a process chamber and an upper electrode device thereof, as well as semiconductor process equipment, to solve the problem that related technologies cannot simultaneously solve the ignition difficulty and the plasma bombardment of the dielectric window.

[0005] In order to solve the above technical problems, this application provides the following technical solutions:

[0006] In a first aspect, embodiments of the present application disclose an upper electrode device for a process chamber. The upper electrode device includes a radio frequency coil and an impedance adjuster. The radio frequency coil is wound around a shielding tube of the process chamber, and the shielding tube is sleeved outside a plasma generating chamber of the process chamber.

[0007] The impedance adjusting component is connected in series with the radio frequency coil, and the impedance adjusting component is used to be adjusted to different impedance values ​​in an ignition stage and a reaction stage of the process chamber.

[0008] In a second aspect, an embodiment of the present application discloses a process chamber, which includes a plasma generating chamber, a process reaction chamber, a shielding tube and the upper electrode device described above, wherein the process reaction chamber is connected to the plasma generating chamber.

[0009] In a third aspect, embodiments of the present application disclose a semiconductor process device. The disclosed semiconductor process device includes a controller and the process chamber described above. The controller includes a memory and a processor. The memory stores a computer program. The processor performs the following steps according to the computer program:

[0010] adjusting the impedance adjusting member to a first preset impedance value;

[0011] applying radio frequency power to the radio frequency coil and determining whether ignition is successful;

[0012] When the ignition is successful, the impedance adjustment member is adjusted to a second preset impedance value, which is greater than the first preset impedance value.

[0013] The technical solution adopted in this application can achieve the following technical effects:

[0014] The process chamber disclosed in the embodiments of the present application improves the structure of the upper electrode device by adding an impedance adjuster with an adjustable impedance value, which is connected in series with the radio frequency coil. This allows the impedance adjuster to be adjusted to different impedance values ​​during the ignition and process stages, respectively. This allows the voltage of the radio frequency coil to be adjusted by adjusting the impedance value of the impedance adjuster. During the ignition stage, the voltage of the radio frequency coil can be increased, thereby increasing the electric field coupled into the plasma generation chamber and making ignition more successful. Furthermore, during the process stage, the voltage of the radio frequency coil can be adjusted by adjusting the impedance value of the impedance adjuster, thereby decreasing the voltage of the radio frequency coil and reducing the electric field coupled into the plasma generation chamber, ultimately mitigating plasma bombardment of the dielectric window of the plasma generation chamber.

[0015] It can be seen that the upper electrode device disclosed in the embodiment of the present application can solve the difficult-to-reconcile contradiction between ignition difficulty and reducing plasma bombardment of the dielectric window by adding an impedance adjustment part and changing the impedance value of the impedance adjustment part during the ignition stage and the process stage. At the same time, there is no need to design the RF coil into a lifting structure. The RF coil can be fixedly wound outside the shielding tube, thereby avoiding the problem of abnormal discharge in the RF coil lifting scheme, and further avoiding the problem of corresponding components being easily damaged due to abnormal discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following is a brief introduction to the drawings required for use in the embodiments or descriptions of the prior art in conjunction with the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] FIG1 is a schematic diagram of a partial structure of a process chamber disclosed in an embodiment of the present application;

[0018] FIG2 is a cross-sectional view of FIG1 , wherein both FIG1 and FIG2 do not show the process reaction chamber of the process chamber;

[0019] FIG3 is a schematic diagram of a portion of the structure in FIG1 ;

[0020] FIG4 is a schematic structural diagram of a shielding cylinder disclosed in an embodiment of the present application;

[0021] 5 and 6 are schematic structural diagrams of the radio frequency coil and plasma generating chamber according to the present invention;

[0022] FIG7 is a circuit diagram of the upper electrode device shown in FIG1;

[0023] FIG8 is a schematic diagram showing the effect of the impedance adjustment member on the potential of the radio frequency coil in the upper electrode device shown in FIG1 ;

[0024] FIG9 is a schematic diagram of an ignition process disclosed in an embodiment of the present application;

[0025] FIG10 is a schematic diagram of a partial structure of another process chamber disclosed in an embodiment of the present application, wherein FIG10 does not show the process reaction chamber of the process chamber;

[0026] FIG11 is a schematic diagram of a portion of the structure of FIG10;

[0027] FIG12 is a schematic diagram of a portion of the structure of FIG11;

[0028] FIG13 is a schematic diagram of a portion of the structure of FIG12;

[0029] FIG14 is a circuit diagram of the upper electrode device shown in FIG10;

[0030] 15 and 16 are potential distribution diagrams of the RF coil of the upper electrode device shown in FIG1 and FIG10 in the ignition stage, respectively;

[0031] 17 and 18 are potential distribution diagrams of the lower RF coil of the upper electrode device shown in FIG1 and FIG10 at the process stage, respectively;

[0032] FIG19 is a schematic diagram of another ignition process disclosed in an embodiment of the present application;

[0033] FIG20 is a flowchart of the execution steps of the processor of the semiconductor process equipment disclosed in the embodiment of the present application.

[0034] 8 , 9 , and 19 refer to the RF coil 11 , the source end in FIG. 7 , FIG. 8 , FIG. 14 , FIG. 15 , FIG. 16 , FIG. 17 , and FIG. 18 refers to the first end of the RF coil 11 , the end end refers to the second end of the RF coil 11 , and the power in FIG. 9 and 19 refers to the RF power.

[0035] Explanation of the accompanying drawings: 10-upper electrode device, 11-RF coil, 12-impedance adjustment member, 13-driving mechanism, 121-first sub-impedance adjustment member, 122-second sub-impedance adjustment member, 20-plasma generating chamber, 30-RF power supply, 40-matching device, 50-process gas inlet pipe, 60-gas nozzle, 70-shielding tube, 71-gap, 72-expansion window, 80-shielding box. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] The technical solutions disclosed in various embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0038] Referring to Figures 1 to 19 , embodiments of the present application disclose a process chamber. The disclosed process chamber is at least a portion of semiconductor processing equipment. The disclosed process chamber may include an upper electrode assembly 10, a plasma generating chamber 20, an RF power supply 30, a matching device 40, a process gas inlet pipe 50, a gas showerhead 60, a shielding tube 70, a process reaction chamber, and the like.

[0039] The upper electrode assembly 10 includes a radio frequency coil 11. The first end of the radio frequency coil 11 can be electrically connected to the radio frequency power supply 30 via a matching device 40, which automatically adjusts impedance matching. Furthermore, the matching device 40 can be electrically connected to the first end of the radio frequency coil 11 via an electrical connection bar to facilitate electrical connection to the radio frequency coil 11. Alternatively, the first end of the radio frequency coil 11 can be directly electrically connected to the matching device 40.

[0040] The second end of the RF coil 11 is used to be electrically connected to the ground. Specifically, the RF coil 11 can be used to be electrically connected to the ground directly or indirectly through other grounding components, which is not limited in the embodiment of the present application.

[0041] The first end of the process gas input pipe 50 can be connected to a process gas source, and the second end of the process gas input pipe 50 can be connected to a gas showerhead 60 mounted on the plasma generating chamber 20, and can be connected to the plasma generating chamber 20 through the gas showerhead 60. The process gas can flow from the process gas source and then enter the plasma generating chamber 20 along the process gas input pipe 50 and the gas showerhead 60, thereby preparing for the subsequent formation of plasma in the plasma generating chamber 20. The gas showerhead 60 can be configured to distribute the process gas so that the process gas is delivered to the plasma generating chamber 20 as evenly as possible. The plasma generating chamber 20 can be a dielectric tube made of materials such as quartz and ceramic. The dielectric tube can be cylindrical or have other shapes, which are not limited in the present embodiment.

[0042] The shielding tube 70 performs a shielding function. The shielding tube 70 can be a Faraday cage. The shielding tube 70 is mounted outside the plasma generating chamber 20 to provide a certain shielding effect. The RF coil 11 is wrapped around the shielding tube 70. When energized, the RF coil 11 generates magnetic and electric fields. The shielding tube 70 barely loses the magnetic field coupled to the plasma generating chamber 20, but it shields the electric field generated by the RF coil 11, thereby reducing the electric field coupled from the RF coil 11 into the plasma generating chamber 20. In other words, the RF coil 11 is not only wrapped around the shielding tube 70, but also around the plasma generating chamber 20.

[0043] During the specific working process, the RF power supply 30 transmits RF power (which can be understood as RF energy) to the RF coil 11 through the matcher 40, and finally introduces it to the ground. Of course, in the case where the process chamber includes the shielding box 80 described later, the RF power can be transmitted from the RF coil 11 to the shielding box 80, and finally introduced to the (RF) ground through the shielding box 80. During this process, the RF coil 11 couples the magnetic field and the electric field into the plasma generating chamber 20. The electric field is applied to the process gas that has been input into the plasma generating chamber 20, thereby causing the process gas to dissociate and form plasma, and then complete the ignition. The magnetic field determines the distribution density of the plasma, and the magnetic field is applied to the plasma so that the density of the plasma meets the requirements. The process reaction chamber is connected to the plasma generating chamber 20, and the plasma with a density that meets the process requirements will enter the process reaction chamber from the plasma generating chamber 20 to participate in the process reaction. The process reaction chamber can be located below the plasma generating chamber 20 and connected to the plasma generating chamber 20.

[0044] As can be seen from the above description, the process gas needs to form a plasma before participating in the process reaction. Accordingly, the process chamber disclosed in the embodiment of the present application needs to go through an ignition phase and a reaction phase during operation. The reaction phase occurs after the ignition phase is completed. Of course, the normal progress of the reaction phase requires the ignition phase to be successfully ignited.

[0045] The shielding tube 70 can shield a portion of the electric field of the RF coil 11. The shielding tube 70 is grounded, so the potential of the shielding tube 70 is low, which in turn reduces the potential difference between the formed plasma and the shielding tube 70. In turn, the potential difference between the plasma and the dielectric window of the plasma generating chamber 20 (the dielectric window is located between the shielding tube 70 and the plasma) is reduced. This can reduce the bombardment of the dielectric window by the plasma under the action of the electric field, thereby extending the service life of the plasma generating chamber 20. Optionally, the shielding tube 70 can be installed in a shielding box 80 described below and can be electrically connected to the shielding box 80, and ultimately grounded through the shielding box 80.

[0046] The process gas needs to be ignited before forming a plasma, that is, the process chamber described above will go through an ignition stage when it is in operation. In the process of realizing this application, the inventors of the present application found that although the shielding tube 70 can play a shielding function and prevent plasma from bombarding the plasma generating chamber 20, it will also reduce the electric field of the radio frequency coil 11 coupled to the plasma generating chamber 20. The ignition stage requires the radio frequency coil 11 to increase the capacitive coupling, thereby allowing more electric field to be coupled into the plasma generating chamber 20 to achieve the start (i.e., ignition) of the process gas. This requirement is difficult to achieve precisely because of the shielding function of the shielding tube 70. In other words, the provision of the shielding tube 70 can indeed alleviate the bombardment of the dielectric window by the plasma, but it will cause ignition difficulties during the ignition stage, ultimately making it difficult to successfully ignite. If you want to solve the problem of ignition difficulties, you need to try not to set the shielding tube 70. It can be seen that solving the ignition difficulties and solving the plasma bombardment of the plasma generating chamber 20 have become a contradiction that is difficult to reconcile.

[0047] Based on this, in some related technologies, the inventors have improved the process chamber, enabling the RF coil 11 to be raised and lowered relative to the plasma generation chamber 20. This design utilizes Paschen's law. Since the ignition voltage is related to the discharge distance, increasing the height of the RF coil 11 can change the ignition distance (i.e., the discharge distance) between the RF coil 11 and the ground, thereby facilitating the formation of a higher voltage across the RF coil 11 for ignition and, in turn, ensuring successful ignition. Once ignition is successful, the height of the RF coil 11 is lowered, bringing it closer to the process reaction chamber, thereby ensuring efficient process reactions.

[0048] However, the inventors further discovered that the current of the RF coil 11 is relatively high, and the electrical connection strips connecting the RF coil 11 to the matcher 40 or the RF power supply 30 are generally wide and rigid. The RF coil 11 carries an extremely high voltage. If there is a loose connection between the electrical connection strips and the RF coil 11, abnormal discharge at the contact point is likely to occur, thereby causing damage to the components (RF coil 11, electrical connection strips) and process failure. To avoid abnormal discharge, the electrical connection strips and the RF coil 11 must be connected in a manner of good rigid contact. This means that the RF coil 11 needs to be fixedly installed. Obviously, this makes it difficult to design the RF coil 11 into a movable structure that can be raised and lowered. Next, the voltage of the RF coil 11 is typically several thousand volts or even tens of thousands of volts, while the shielding tube 70 is grounded. To ensure coupling efficiency, the distance between the RF coil 11 and the shielding tube 70 is minimal, only a few to a dozen millimeters. Therefore, the voltage resistance design between the RF coil 11 and the shielding tube 70 requires special attention. During the lifting and lowering process, the RF coil 11 is prone to abnormal discharge with the shielding tube 70. Therefore, the lifting and lowering design of the RF coil 11 requires high voltage resistance design requirements. If care is not taken, the lifting and lowering RF coil 11 is prone to arc discharge with the shielding tube 70, further damaging the components (RF coil 11 and shielding tube 70). Furthermore, the lifting and lowering of the RF coil 11 requires considerable time and also causes the load impedance of the matching element 40 to change, requiring the matching element 40 to re-match the impedance. This ultimately results in a longer ignition phase and lowers the production capacity of the process chamber.

[0049] Based on the various problems listed above, the inventors of the present application have further improved the structure of the process chamber so that the upper electrode device 10 involved in the embodiment of the present application can also include an impedance adjustment component.

[0050] In an embodiment of the present application, an impedance adjuster is connected in series with the RF coil 11. The impedance adjuster is used to adjust the impedance to different values ​​during the ignition and reaction phases of the process chamber. In some optional embodiments, the impedance adjuster is an electrical device with adjustable impedance, such as an adjustable capacitor, whose impedance value is changed by adjusting the capacitance value; in other optional embodiments, the impedance adjuster may also be an adjustable inductor, whose impedance value is changed by adjusting the inductance value. This application does not limit this, as long as the impedance adjuster can adjust its own impedance.

[0051] The following describes the upper electrode device 10 of the embodiment of the present application in detail, taking the impedance adjustment member being the adjustable capacitor 12 as an example:

[0052] As shown in Figure 1, an adjustable capacitor 12 is connected in series with the RF coil 11. The adjustable capacitor 12 is configured to have different capacitance values ​​during the ignition and reaction phases of the process chamber. In this case, during the ignition phase, the capacitance of the adjustable capacitor 12 is adjusted, causing its impedance to change accordingly. This allows the voltage of the RF coil 11 to be adjusted to a higher voltage after the impedance matching device 40 performs impedance matching. This allows the electric field generated by the RF coil 11 to still couple a larger electric field into the plasma generating chamber 20 even after being partially shielded by the shielding tube 70, thereby facilitating successful ignition. After the ignition phase is completed and the process phase begins, in order to prevent the electric field generated by the RF coil 11 from being excessively coupled into the plasma generating chamber 20, the capacitance value of the adjustable capacitor 12 is further adjusted, thereby further changing its impedance value. This allows the voltage of the RF coil 11 to be adjusted to a lower voltage after the matcher 40 performs impedance matching adjustment. As a result, after the electric field generated by the RF coil 11 is partially shielded by the shielding tube 70, the electric field that can be coupled into the plasma generating chamber 20 is already smaller, and the plasma will not be driven by the larger electric field to bombard the plasma generating chamber 20.

[0053] Specifically, in the ignition stage, the capacitance value of the adjustable capacitor 12 can be adjusted to a first capacitance value (i.e., the impedance value of the impedance adjustment member is adjusted to the first impedance value accordingly), and the matcher 40 performs impedance matching adjustment based on the first capacitance value, so that the voltage of the RF coil 11 is adjusted to a first voltage, and the first voltage is greater than the ignition voltage. It should be noted that, in this article, the ignition voltage refers to the voltage corresponding to the successful ignition, and the embodiment of the present application does not limit the specific value of the ignition voltage. In the reaction stage, the capacitance value of the adjustable capacitor 12 is adjusted to a second capacitance value (i.e., the impedance value of the impedance adjustment member is adjusted to the second impedance value accordingly), and the matcher 40 performs impedance matching adjustment based on the second capacitance value, so that the voltage of the RF coil 11 is adjusted to a second voltage, and the second voltage is less than the ignition voltage, thereby avoiding coupling a large electric field into the plasma generating chamber 20. Among them, the first capacitance value is less than the second capacitance value (i.e., the first impedance value is greater than the second impedance value).

[0054] In the process chamber disclosed in the embodiments of the present application, the structure of the upper electrode assembly 10 is improved by adding an adjustable capacitor 12 with an adjustable capacitance value, which is connected in series with the RF coil 11. This allows the adjustable capacitor 12 to be adjusted to different capacitance values ​​during the ignition and process stages. Adjusting the capacitance of the adjustable capacitor 12 can adjust the voltage of the RF coil 11, resulting in a higher voltage at the RF coil 11 during the ignition stage, which in turn increases the electric field coupled into the plasma chamber 20 (i.e., increases capacitive coupling, resulting in a stronger electric field coupled into the plasma chamber 20), making ignition more successful. Furthermore, adjusting the capacitance of the adjustable capacitor 12 during the process stage can adjust the voltage of the RF coil 11, resulting in a lower voltage at the RF coil 11, which in turn reduces the electric field coupled into the plasma chamber 20 (i.e., reduces capacitive coupling, resulting in a weaker electric field coupled into the plasma chamber 20). This ultimately reduces plasma bombardment of the dielectric window of the plasma chamber 20.

[0055] It can be seen that the upper electrode device 10 disclosed in the embodiment of the present application can solve the difficult contradiction between ignition difficulty and reducing plasma bombardment on the dielectric window by adding an impedance adjustment component such as an adjustable capacitor 12 and changing the capacitance value of the adjustable capacitor 12 (i.e., changing the impedance value of the impedance adjustment component) during the ignition stage and the process stage. At the same time, there is no need to design the RF coil 11 into a lifting structure. The RF coil 11 can be fixedly wound outside the shielding tube 70, thereby avoiding the problem that the corresponding components are more easily damaged due to abnormal discharge in the lifting scheme of the RF coil 11.

[0056] As mentioned above, the impedance adjustment component is connected in series with the RF coil 11. Specifically, there are many ways to connect the impedance adjustment component and the RF coil 11 in series. In an optional solution, taking the impedance adjustment component as an adjustable capacitor 12 as an example, the first end of the RF coil 11 is used to electrically connect to the RF power supply 30, and the second end of the RF coil 11 is used to be grounded. The adjustable capacitor 12 can be connected between the second end of the RF coil 11 and the ground, thereby achieving series connection with the RF coil 11. This design method connects the adjustable capacitor 12 between the second end of the RF coil 11 and the ground, which can easily ensure the integrity of the RF coil 11 (that is, the RF coil 11 can be wound by a whole wire), and at the same time avoid major changes to the RF coil 11 as much as possible. That is to say, on the basis of the RF coil 11 in the process chamber of the related technology, an adjustable capacitor 12 can be added between its second end and the ground. The change is small and easy to implement.

[0057] Furthermore, there may be one impedance adjuster or at least two impedance adjusters, and the embodiment of the present application does not limit the number of impedance adjusters. Of course, when there are at least two impedance adjusters connected in series between the second end of the RF coil 11 and the ground, these impedance adjusters may be connected in series or in parallel between the second end of the RF coil 11 and the ground.

[0058] Specifically, taking the impedance adjustment member as an adjustable capacitor 12 as an example, the RF coil 11 can be wound with a whole wire, and the adjustable capacitor 12 is connected between the second end of the RF coil 11 and the ground. The impedance value of the adjustable capacitor 12 in the ignition stage can be greater than Z coil , for example 1.2Z coil , the impedance value of the adjustable capacitor 12 in the reaction stage can be greater than 0 and less than Z coil Optionally, the impedance value of the adjustable capacitor 12 in the reaction stage is greater than 0.4Z coil and less than 0.6Z coil In a further optional solution, the impedance value of the adjustable capacitor 12 in the reaction stage is equal to 0.5Z coil , where Z coil is the impedance value of the RF coil 11. This optional solution is more likely to address both the ignition difficulty and the plasma bombardment of the plasma generating chamber 20. Detailed description will be given below with reference to FIG7 and FIG8.

[0059] In Figures 7 and 13, the matcher (i.e., the Match in Figures 7, 9, 14, and 19) 40 can adopt a mature and commonly used L-shaped fully automatic matcher currently on the market. The sensor (Sensor) inside the matcher 40 reads the RF voltage and RF current and calculates the impedance value. Through the control program, the capacitance value of the adjustable capacitor 12 is adjusted, so that the rear-end impedance of the upper electrode device 10 matches the impedance of the front-end RF power supply 30, ensuring that as much RF power (which can also be considered as RF energy) as possible can be transmitted to the rear-end load of the upper electrode device 10 (the rear-end load includes the RF coil 11 and the adjustable capacitor 12). It should be noted that the matcher 40 in this article plays the purpose of matching impedance. Its structure and working principle are all well-known mature technologies and will not be repeated here. Those skilled in the art should understand that other types of matchers can also be used in the embodiments of the present application, and this application does not impose any limitation on this.

[0060] Please refer to FIG. 7 , the inductance of the RF coil 11 is L coil, the real impedance of the RF coil 11 and other loads is R, the adjustable capacitor 12 connected to the second end of the RF coil 11 is C3, the first tuning capacitor and the second tuning capacitor of the matcher 40 are C1 and C2 respectively, and the first tuning capacitor and the second tuning capacitor are used to adjust the back-end load impedance to the impedance output by the RF power supply 30 (for example, 50Ω) to ensure that the maximum power is transmitted to the back-end load. Assume that the current flowing into the RF coil 11 is I, and the voltage at the source end of the RF coil 11 (that is, the first end of the RF coil 11) is V. There is a voltage and current sensor (Sensor) at the output end of the matcher 40, which can be used to monitor the potential of the source end of the RF coil 11. The potential of the source end of the RF coil 11 is: V=I(R+Z coil +Z c3 ) (1)

[0061] The impedance of the RF coil 11 is Z coil =jωL coil , the impedance of the adjustable capacitor 12 (i.e. C3) is Angular frequency ω=2πf, where f is the frequency of the output signal of the RF power supply 30. After the matching device 40 meets the impedance matching condition, the output power of the RF power supply 30 satisfies Power=I 2 R, then the potential of the source end of the RF coil 11 is:

[0062] In an inductively coupled plasma source, if the structure of the RF coil 11 remains unchanged, the plasma density is positively correlated with the current flowing through the RF coil 11. The greater the current flowing through the RF coil 11, the higher the plasma density. Adjusting the capacitance of the adjustable capacitor 12 (i.e., C3) at the second end of the RF coil 11 and realigning capacitors C1 and C2 through the matcher 40 maintains virtually no change in the current flowing through the RF coil 11, without affecting the induced plasma density. However, the voltage distribution across the RF coil 11 can be altered. By reducing the average and maximum potentials across the RF coil 11, capacitive coupling can be reduced, lowering the electric field strength within the sheath. This reduces the plasma's impact on the dielectric window during electric field acceleration, thereby mitigating plasma bombardment of the dielectric window of the plasma generating chamber 20.

[0063] The structure of the RF coil 11 remains unchanged, and the impedance Z of the RF coil 11 is coilChanging the size of the adjustable capacitor (i.e., C3) 12 does not affect the current flowing through the RF coil 11. It should be noted that for the impedance Z = R + jX, R is the real impedance, and the power it consumes is active power; X is the imaginary impedance, and the power it consumes is reactive power. The power output by the RF power supply 30 is all active power. The process chamber (such as the etcher) generally uses a constant power RF power supply 30. The RF power (i.e., Power) of the RF power supply 30 is constant. According to Power = I 2 Changing the value of the adjustable capacitor (i.e., C3) 12 only changes the imaginary impedance X, without affecting the value of the real impedance R, and therefore does not affect the value of the current I. It can be seen that the potential difference ΔV across the RF coil 11 is essentially the same, and is here uniformly expressed as: ΔV = I·jωL coil =2V0 (3)

[0064] At the same RF power, the potential difference across the RF coil 11 is 2V0. The effect of different C3 capacitance values ​​on the potential distribution on the RF coil 11 is shown in FIG8 , and the corresponding values ​​are shown in FIG8 and Table 1. It can be seen that at Z C3 >Z coil When Z, the average potential and the maximum potential on the RF coil 11 are both large, and the electric field coupled to the plasma generating chamber 20 is the strongest, which is most conducive to ignition. C3 =0.5Z coil When , the average potential and the maximum potential on the RF coil 11 are both minimum, at which time the electric field coupled to the plasma generating chamber 20 is weakest, and the plasma in the sheath bombarding the plasma generating chamber 20 is weakest.

[0065] Table 1

[0066] Based on this characteristic, in case 6 of Table 1, the average potential of RF coil 11 is the highest, and the electric field is the strongest, which is conducive to ignition. The capacitance setting of adjustable capacitor 12 in case 6 can be used for gas ignition and dissociation of the process gas, thereby forming a plasma. In case 3 of Table 1, the average potential of RF coil 11 is the lowest, and the electric field is the weakest. The capacitance setting of adjustable capacitor 12 in case 3 is more suitable for the process reaction process (i.e., more suitable for the reaction stage).

[0067] To understand the ignition process, please refer to Figure 9. Before loading the RF power, adjust C3 to meet Z C3 =1.2Z coil >Z coil Of course, only Z C3 >Z coil For example: Z C3It can actually be preset to 1.1Z coil , 1.3Z coil However, the capacitance value of C3 cannot be adjusted beyond the lower limit of C3's capacitance range. Under this condition, the overall potential of the RF coil 11 is relatively high. After ventilating and controlling the pressure of the chamber (i.e., plasma generator 20), RF power is applied and impedance matching is performed by adjusting C1 and C2 of the Match (i.e., matcher 40). This ensures that the RF power is applied to the load, such as the RF coil 11. At this point, the electric field formed by the RF coil 11 is relatively strong, which is conducive to ignition.

[0068] How to determine whether the ignition is successful: The output end of the Match is equipped with a voltage and current sensor (i.e., the Sensor in the figure). In the early stage, the static impedance voltage V1 at the ignition moment and the voltage V2 after the ignition are collected through manual testing. Since V2 is significantly smaller than V1, the voltage threshold V0 = 0.5V1 + 0.5V2 can be specified. At the moment of ignition, the Sensor reads the voltage V. If V drops from greater than V0 to less than V0, it is considered that the ignition is successful. If the ignition fails, continue to reduce the value of C3 (for example, the current value of C3 multiplied by 0.9 is the capacitance value of C3 after adjustment) and re-match until the ignition is successful.

[0069] After the ignition is successful, readjust C3 so that the impedance value of C3 meets Z C3 =0.5Z coil In this case, the overall potential of the RF coil 11 is the lowest. Then Match adjusts C1 and C2 for impedance matching, so that the RF power is fully loaded on the RF coil 11 and other loads again, and then enters the process stage.

[0070] As described above, the first end of the RF coil 11 is used to electrically connect to the RF power supply 30 of the process chamber, and the second end of the RF coil 11 is used to ground. The impedance adjuster includes at least one first sub-impedance adjuster, and the RF coil includes at least two coil segments connected in series, with each first sub-impedance adjuster connected in series between two adjacent coil segments. In another embodiment, still taking the impedance adjuster as an adjustable capacitor 12 as an example, the adjustable capacitor 12 may include at least one first sub-adjustable capacitor 121, and the RF coil 11 may include at least two coil segments connected in series, with each first sub-adjustable capacitor 121 connected in series between two adjacent coil segments. In this case, the RF coil 11 is not a single piece of wire, but rather multiple separate segments of wire (at least two segments). In this case, during the capacitance adjustment process of the adjustable capacitor 12, the capacitance of the first sub-adjustable capacitor 121 may be adjusted to achieve the purpose of this application.

[0071] For example, the RF coil 11 may include two coil segments, and the first sub-adjustable capacitor 121 may be one and connected between the two coil segments.

[0072] In a more specific technical solution, there are multiple first sub-adjustable capacitors 121, and the impedance values ​​of each first sub-adjustable capacitor 121 are equal and greater than the impedance value of the second sub-adjustable capacitor 122. As shown in Figures 9 to 12, there can be two first sub-adjustable capacitors 121. The RF coil 11 can include three coil segments, and there can be two first sub-adjustable capacitors 121, each connected between two adjacent coil segments.

[0073] Furthermore, the impedance adjuster also includes a second sub-impedance adjuster, which is used to connect between the second end of the RF coil and ground. Referring again to Figures 9 to 12, in a further technical solution, the adjustable capacitor 12 may also include a second sub-adjustable capacitor 122, which is used to connect between the second end of the RF coil 11 and ground. During capacitance adjustment of the adjustable capacitor 12, the capacitance values ​​of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 can be adjusted simultaneously, thereby changing the impedance values ​​of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122, thereby achieving the purpose of this application.

[0074] Taking the impedance adjustment member as an adjustable capacitor 12 as an example, when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, in the ignition stage, the impedance values ​​of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 can be greater than Z coil , for example 1.2Z coil In the reaction stage, the impedance values ​​of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 can be greater than 0 and less than Z coil .

[0075] In other embodiments, during the reaction phase, the impedance value of the first sub-adjustable capacitor 121 may be Z coil / n, the impedance value of the second sub-adjustable capacitor 122 can be Z coil / 2n. This optional solution is more likely to take into account the problem of ignition difficulty and plasma bombardment of the plasma generating chamber 20. Wherein, n is the sum of the number of the first sub-adjustable capacitors 121 and the number of the second sub-adjustable capacitors 122. Specifically, there are 2 first sub-adjustable capacitors 121 and 1 second sub-adjustable capacitor 122. In this case, n is 3. Accordingly, in the reaction stage, the impedance value of the first sub-adjustable capacitor 121 is Z coil / 3, the impedance value of the second sub-adjustable capacitor 122 is Z coil / 6. The following is explained in conjunction with Figures 10 to 18.

[0076] As shown in FIG12 and FIG13 , the RF coil 11 is divided into three coil segments, and the total inductance of the RF coil 11 is L coil , can be divided into 3 parts, the inductance of each section is L coil / 3. The real impedance of the RF coil 11 and other loads is R, the second sub-adjustable capacitor 122 at the second end of the RF coil 11 is C3, and the two first sub-adjustable capacitors 121 connected in series of the RF coil 11 correspond to C4 and C5 in the schematic diagram respectively. The first tuning capacitor and the second tuning capacitor in the fully automatic matcher (Match) 40 are C1 and C2 respectively, which are used to adjust the back-end load impedance to the impedance output by the RF power supply 30 (for example, 50Ω) to ensure maximum power transmission to the back-end load. Assume that the current flowing into the RF coil 11 is I, and the source voltage of the RF coil 11 is V. There is a voltage and current sensor at the output end of Match (such as the Sensor in Figure 14), which can be used to monitor the potential of the source end of the RF coil 11. The potential of the source end of the RF coil 11 is: V=I(R+Z coil +Z3+Z4+Z5) (4)

[0077] The impedance Z of the RF coil 11 is coil =jωL coil , the impedance of the second sub-adjustable capacitor (ie C3) 122 The impedance of the capacitor C4 connected in series with the coil segment (ie, a first sub-adjustable capacitor 121) The impedance of the capacitor C5 connected in series with the coil segment (ie, another first sub-adjustable capacitor 121) Angular frequency ω=2πf, where f is the frequency of the output signal of the RF power supply 30. After Match satisfies the impedance matching condition, the output power of the RF power supply 30 satisfies Power=I 2 R, then the potential of the source end of the RF coil 11 is:

[0078] In an inductively coupled plasma source, if the structure of the RF coil 11 remains unchanged, the plasma density is positively correlated with the current flowing through the RF coil 11. The greater the current flowing through the RF coil 11, the higher the plasma density. By adjusting the capacitance of the second sub-adjustment capacitor (i.e., C3) 122 and the two first sub-adjustment capacitors (i.e., C4 and C5) 121 at the rear end of the RF coil 11, and re-matching C1 and C2 through Match, the current flowing through the RF coil 11 remains virtually unchanged, without affecting the excited plasma density. However, the voltage distribution across the RF coil 11 can be altered. By reducing the average and maximum potentials across the RF coil 11, capacitive coupling can be reduced, lowering the electric field within the sheath region, thereby weakening the plasma's acceleration and bombardment of the plasma generating chamber 20.

[0079] The structure of the RF coil 11 remains unchanged, and the impedance Z of the RF coil 11 is coil Changing the size of C3, C4 and C5 does not affect the current flowing through the RF coil 11, and the potential difference ΔV at both ends of the RF coil 11 is basically the same, which is uniformly recorded as: ΔV=I·jωL coil =2V0 (6)

[0080] At the same RF power, the potential difference between the two ends of the RF coil 11 is 2V0. In the structure shown in Figure 15, the RF coil 11 is divided into three coil segments, and the potential drop of each coil segment is 2V0 / 3≈0.67V0. When the structure in which the adjustable capacitor 12 is only distributed between the second end of the RF coil 11 and the ground is in the ignition stage, the potential distribution of the RF coil 11 is shown in Figure 15. The impedance value Z corresponding to the adjustable capacitor 12 of the RF coil 11 is C3 =1.2Z coil The maximum potential amplitude on the radio frequency coil 11 is 2.4V0.

[0081] When the adjustable capacitor 12 includes two first sub-adjustable capacitors 121 and a second sub-adjustable capacitor 122 and is in the ignition stage, the potential distribution of the RF coil 11 is shown in FIG16 , and the impedance value Z of the second sub-adjustable capacitor 122 connected to the RF coil 11 is C3 =1.2Z coil The impedance values ​​of the two first sub-adjustable capacitors 121 are Z C4 、Z C5 , where Z C4 =Z C5 =1.2Z coil , the maximum potential amplitude on the RF coil 11 is 5.86V0. Thus, compared to the structure of the upper electrode assembly 10 shown in FIG15 , the structure shown in FIG16 enables the RF coil 11 to obtain a higher potential at the moment of ignition, resulting in a stronger electric field coupled to the plasma generating chamber 20, which is more conducive to ignition and complete ignition (i.e., complete ignition).

[0082] When the adjustable capacitor 12 is only distributed between the second end of the RF coil 11 and the ground, in the process stage, the potential distribution of the RF coil 11 is shown in FIG17 , and the impedance value Z of the adjustable capacitor 12 of the RF coil 11 is C3 =0.5Z coil , then the maximum potential amplitude on the RF coil 11 is V0. When the structure of the adjustable capacitor 12 including two first sub-adjustable capacitors 121 and second sub-adjustable capacitors 122 is in the process stage, the potential distribution of the RF coil 11 is shown in Figure 18, and the impedance value Z of the second sub-adjustable capacitor 122 of the RF coil 11 isC3 =Z coil / 6, the impedance values ​​of the two first sub-adjustable capacitors 121 are Z C4 、Z C5 , where Z C4 =Z C5 =Z coil / 3, the maximum potential amplitude on the RF coil 11 is V0 / 3. Compared to the structure shown in FIG17 , the structure shown in FIG18 enables the RF coil 11 to obtain a lower potential during the process, thereby weakening the electric field coupled from the RF coil 11 to the plasma generating chamber 20, which is more conducive to minimizing damage to the plasma generating chamber 20 during the process.

[0083] Based on this feature, the ignition process can be designed as shown in Figure 19. Before loading power, adjust C3, C4, and C5 to meet Z C3 =Z C4 =Z C5 =1.2Z coil >Z coil Under these conditions, the overall potential of the RF coil 11 is relatively high. After venting and controlling the pressure within the chamber (i.e., the plasma chamber 20), RF power is applied and impedance matching is adjusted between C1 and C2 of Match. This ensures that RF power is applied to the load, including the RF coil 11. At this point, the electric field coupled from the RF coil 11 to the plasma chamber 20 is relatively strong, facilitating ignition.

[0084] Method to judge whether the ignition is successful: The output end of Match is equipped with a voltage and current sensor (i.e. Sensor in the figure). In the early stage, the voltage V1 of the static impedance at the moment of ignition and the voltage V2 after the start (i.e. after the ignition is successful) are collected through manual testing. Since V2 is obviously smaller than V1, the voltage threshold V0=0.5V1+0.5V2 can be specified. At the moment of ignition, the Sensor reads the voltage V. If V drops from greater than V0 to less than V0, it is considered that the ignition is successful. If the ignition fails, continue to reduce the values ​​of C3, C4, and C5 (for example, the current values ​​of C3, C4, and C5 multiplied by 0.9 are used as the capacitance values ​​of C3, C4, and C5 after adjustment, which is equivalent to the current Z C3 、Z C4 and Z C5 The impedance value after multiplying by a predetermined coefficient greater than 1 is the adjusted Z C3 、Z C4 and Z C5 impedance value), and rematch until ignition is successful.

[0085] After the ignition is successful, readjust C3, C4, and C5 so that the impedance value of C3 is Z C3 =Z coil / 6, and the impedance values ​​Z corresponding to the capacitance values ​​of C4 and C5 respectively C4 , Z C5 Satisfy Z C4 =Z C5 =Z coil / 3, in this case, the overall potential of the RF coil 11 is the lowest. Then Match adjusts C1 and C2 for impedance matching, so that the RF power is fully loaded on the RF coil 11 and other loads, thus completing ignition and entering the process stage.

[0086] In the embodiment of the present application, there are many ways to adjust the capacitance value of the adjustable capacitor 12. Of course, any capacitor that can adjust the capacitance value can be used as the adjustable capacitor 12. In one embodiment, the upper electrode device 10 disclosed in the embodiment of the present application may further include a driving mechanism 13. The adjustable capacitor 12 may include a first capacitor plate and a second capacitor plate. The driving mechanism 13 may be connected to at least one of the first capacitor plate and the second capacitor plate. The driving mechanism 13 is used to drive at least one of the first capacitor plate and the second capacitor plate to move, so as to adjust at least one of the distance and relative area between the first capacitor plate and the second capacitor plate to adjust the capacitance value of the adjustable capacitor 12. For example, the driving mechanism 13 is connected to the first capacitor plate or the second capacitor plate through a power connection shaft, thereby adjusting the rotation or movement of the first capacitor plate or the second capacitor plate, thereby achieving the purpose of adjusting the capacitance value. The method of using the driving mechanism 13 to adjust the capacitance value of the adjustable capacitor 12 can quickly achieve the purpose of adjusting the voltage of the RF coil 11. Compared with the raising and lowering adjustment of the RF coil 11, the method of using the driving mechanism 13 in conjunction with the adjustable capacitor 12 can achieve successful ignition more quickly, which is conducive to improving production capacity.

[0087] Of course, when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121, the process chamber can be configured with a corresponding driving mechanism for the first sub-adjustable capacitor 121, so that the driving mechanism adjusts the capacitance value of the first sub-adjustable capacitor 121 by driving at least one of the two capacitor plates of the first sub-adjustable capacitor 121. When the adjustable capacitor 12 includes a second sub-adjustable capacitor 122, the process chamber can also be configured with a corresponding driving mechanism for the second sub-adjustable capacitor 122, so that the driving mechanism adjusts the capacitance value of the second sub-adjustable capacitor 122 by driving at least one of the two capacitor plates of the second sub-adjustable capacitor 122.

[0088] As described above, the shielding tube 70 can have various structures, and the shielding tube 70 is a hollow cylindrical member. Specifically, the shielding tube 70 can be provided with a plurality of slits 71 extending axially along the shielding tube 70, and the plurality of slits 71 are spaced apart along the circumferential direction of the shielding tube 70. The plurality of slits 71 can be evenly distributed in the circumferential direction of the shielding tube 70, thereby facilitating the RF coil 11 to more evenly couple a more uniform magnetic field into the plasma generating chamber 20 through the shielding tube 70, thereby facilitating the plasma generated in the plasma generating chamber 20 to meet the process requirements. The number of slits 71 can be 6, or 4 or 8. The embodiment of the present application does not limit the specific number of slits 71.

[0089] The widths of the gap 71 can be equal at all locations. In other words, the widths of the gap 71 at both ends of the axial direction can be equal to the widths of any region between the ends of the gap 71. The width of the gap 71 is circumferentially circumferentially of the shielding tube 70. However, this is not limiting. In other embodiments, the widths of the gap 71 at both ends of the axial direction can be greater than the width at a predetermined location between the ends of the gap 71. The RF coil 11 is wound around the outer circumference of the shielding tube 70 and axially located at the predetermined location of the gap 71. As described above, because the impedance adjuster 12 can adjust the voltage distribution of the RF coil 11, the voltage across the RF coil 11 can be increased during the ignition phase. This, in turn, allows the RF coil 11 to couple to a larger electric field within the plasma generation chamber 20. Ultimately, even with a smaller width of the gap 71, ignition can be easily ensured. In this embodiment, the RF coil 11 is wound around a predetermined position between the two ends of the slit 71, where the width is smaller. Since the width of the slit 71 at the predetermined position is smaller than the widths at the two ends of the slit 71, the electric field of the RF coil 11 can be better shielded during the process stage, thereby minimizing the electric field coupling into the plasma generation chamber 20 during the process stage. At the same time, the magnetic field can be coupled from the shielding tube 70 into the plasma generation chamber 20 without being damaged.

[0090] Of course, since the RF coil 11 is wound at a predetermined position between the two ends of the gap 71 , and considering the magnetic field distribution of the RF coil 11 , the widths of the two ends of the gap 71 are larger, making it easier for the magnetic field generated by the RF coil 11 to couple into the plasma generating chamber 20 .

[0091] It should be noted that, in this embodiment, the RF coil 11 may be axially spaced at equal or unequal distances from both ends of the gap 71. In other embodiments not shown in the figures, the RF coil 11 may be axially spaced closer to one end of the gap 71 and farther from the other end. This is not a limitation herein.

[0092] In a further technical solution, the shielding tube 70 may further be provided with a plurality of flared windows 72, which are correspondingly connected to the ends of the plurality of slots 71 along the axial direction, for example, in a one-to-one correspondence. The width of the plurality of flared windows 72 in the slot 71 is greater than the width of the corresponding slot 71. In other words, the circumferential dimension of the plurality of flared windows 72 in the shielding tube 70 is greater than the circumferential dimension of the corresponding slot 71 in the shielding tube 70. In this case, since the bottom end of the shielding tube 70 is used for grounding, the opening at the bottom end of the shielding tube 70 is relatively easy to be blocked (for example, by the shielding box 80 described later). The flared windows 72 can ensure that the magnetic field generated by the RF coil 11 is sufficiently coupled to the plasma generating chamber 20 through the flared windows 72, thereby ensuring an inductive coupling effect.

[0093] As described above, the shielding tube 70 is used for grounding, thereby ensuring that the potential of the shielding tube 70 is low, reducing the potential difference between the shielding tube 70 and the plasma, and thus avoiding plasma bombardment of the plasma generating chamber 20. In an optional embodiment, the shielding tube 70 may include a plurality of grounding portions. The plurality of grounding portions are located at the ends of the shielding tube 70 and can be evenly distributed along the circumferential direction of the shielding tube 70. By designing a plurality of grounding portions evenly distributed in the circumferential direction, the shielding tube 70 can be grounded symmetrically at multiple points, thereby achieving grounding in a more balanced manner, and ultimately ensuring the symmetry of the return path to ensure the uniformity of the electromagnetic field coupled to the plasma generating chamber 20. The plurality of grounding portions can be located at the lower bottom end of the shielding tube 70, or at the higher top end of the shielding tube 70, and the embodiments of the present application are not limited thereto.

[0094] Of course, as described above, when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121, or when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, since the shielding tube 70 is provided with a plurality of gaps 71 spaced apart along the circumferential direction of the shielding tube 70, in this case, the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 may be opposite to the gap 71, thereby easily causing angular asymmetry of the electromagnetic field. Based on this, the shielding tube is provided with a plurality of gaps spaced apart along the circumferential direction of the shielding tube, and the first sub-impedance adjustment member and the second sub-impedance adjustment member are both staggered with the gaps. In one embodiment, taking the adjustable capacitor 12 including the first sub-adjustable capacitor 121 as an example, the first sub-adjustable capacitor 121 can be staggered with the gap 71, that is, the first sub-adjustable capacitor 121 (i.e., the first sub-impedance adjustment member) can avoid the position of the gap 71 and be located between two adjacent gaps 71. Of course, if the adjustable capacitor 12 includes a second sub-adjustable capacitor 122, the second sub-adjustable capacitor 122 can also be staggered relative to the gap 71. In other words, the second sub-adjustable capacitor 122 (i.e., the second sub-impedance adjustment element) can also avoid the gap 71 and be located between two adjacent gaps 71, as shown in Figures 10 and 11. This staggered distribution method will hardly cause eccentricity in the process results due to the discontinuity of the RF coil 11.

[0095] The process chamber disclosed in the embodiment of the present application may also include a shielding box 80, which is used for grounding. The second end of the RF coil 11 is electrically connected to the shielding box 80 to achieve grounding. The plasma generating chamber 20, the shielding tube 70, the RF coil 11 and the adjustable capacitor 12 can be arranged inside the shielding box 80, so as to be protected by the shielding box 80, while also being able to prevent the magnetic field that may exist in the external environment from interfering with the magnetic field generated by the RF coil 11. The shielding tube 70 is electrically connected to the shielding box 80 to achieve grounding. In the embodiment of the present application, the shielding tube 70 and the shielding box 80 can both be made of metal.

[0096] In the case where the process chamber includes a drive mechanism 13, as shown in Figures 1 and 2, in an optional embodiment, the drive mechanism 13 can be installed outside the shielding box 80 and connected to the adjustable capacitor 12 located inside the shielding box 80 via a connecting shaft. This arrangement can alleviate the adverse effects that the drive mechanism 13 may have on the magnetic field generated by the RF coil 11 when it is located inside the shielding box 80. In other words, because the drive mechanism 13 is located outside the shielding box 80, the effect of the drive mechanism 13 on the magnetic field generated by the RF coil 11 can be alleviated compared to when the drive mechanism 13 is located inside the shielding box 80.

[0097] In a further embodiment, the RF power supply 30 and the matching device 40 may be located outside the shielding box 80 and mounted on the shielding box 80. In this case, the shielding box 80 can also provide a mounting location for the RF power supply 30 and the matching device 40. Of course, the RF power supply 30 and the matching device 40 are located outside the shielding box 80 to avoid adverse effects on the components inside the shielding box 80.

[0098] Based on the process chamber disclosed in the embodiments of this application, the embodiments of this application further disclose a semiconductor process apparatus, comprising a controller and the process chamber described in any of the embodiments above. The controller comprises a memory and a processor. The memory stores a computer program. The processor, in accordance with the computer program, executes the following steps:

[0099] adjusting the impedance adjusting member to a first preset impedance value;

[0100] Applying radio frequency power to the radio frequency coil 11 and determining whether ignition is successful;

[0101] When the ignition is successful, the impedance adjustment member is adjusted to a second preset impedance value, which is smaller than the first preset impedance value.

[0102] As shown in FIG. 20 , taking the impedance adjustment component as the adjustable capacitor 12 as an example, S101 . Adjust the adjustable capacitor 12 to a first preset capacitance value, so that the impedance value of the adjustable capacitor 12 is correspondingly adjusted to the first preset impedance value.

[0103] In one embodiment, when the adjustable capacitor 12 is only connected between the second end of the RF coil 11 and the ground, in this step, the capacitance value of the adjustable capacitor 12 can be adjusted to a first preset capacitance value so that the impedance value of the adjustable capacitor 12 is greater than Z coil , for example 1.2Z coil , so that the potential of the RF coil 11 is higher after being loaded with RF power.

[0104] In another embodiment, when the adjustable capacitor 12 includes the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 described above, in this step, the capacitance values ​​of the two first sub-adjustable capacitors (i.e., C4 and C5) 121 and the second sub-adjustable capacitor (i.e., C3) 122 can be adjusted to the first preset capacitance value, so that the impedance value of the second sub-adjustable capacitor 122 and the impedance values ​​of the two first sub-adjustable capacitors 121 can be greater than Z coil , for example 1.2Z coil , so that the potential of the RF coil 11 is higher after being loaded with RF power.

[0105] S102 . Apply radio frequency power to the radio frequency coil 11 .

[0106] Of course, before applying RF power, it is necessary to introduce process gas into the plasma generating chamber 20 and control the gas pressure within the plasma generating chamber 20. After applying RF power, the matching device 40 automatically adjusts its own C1 (i.e., the first tuning capacitor of the matching device 40) and C2 (i.e., the second tuning capacitor of the matching device 40) to perform impedance matching, so that the RF power is applied to the load such as the RF coil 11.

[0107] S103. Determine whether the ignition is successful.

[0108] S104 . When the ignition is successful, the adjustable capacitor 12 is adjusted to a second preset capacitance value, so that the impedance value of the adjustable capacitor 12 is correspondingly adjusted to the second preset impedance value.

[0109] In one embodiment, when the adjustable capacitor 12 is only connected between the second end of the RF coil 11 and the ground, in this step, the capacitance value of the adjustable capacitor (i.e., C3) 12 can be adjusted to a second preset capacitance value so that the impedance value of the adjustable capacitor 12 is 0.5Z coil , thereby making the potential of the RF coil 11 lower. The second preset capacitance value is greater than the first preset capacitance value, that is, the second preset impedance value is less than the first preset impedance value.

[0110] In another embodiment, when the adjustable capacitor 12 includes the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 described above, in this step, the capacitance values ​​of the two first sub-adjustable capacitors (i.e., C4 and C5) 121 and the second sub-adjustable capacitor (i.e., C3) 122 can be adjusted respectively so that the impedance value of the second sub-adjustable capacitor 122 is Z coil / 6. The impedance values ​​of the two first sub-adjustable capacitors 121 can be Z coil / 3, so that the potential of the RF coil 11 is lower after the RF power is loaded.

[0111] Of course, after S104 , the matcher 40 may be controlled to automatically adjust its own C1 and C2 to perform impedance matching, so that the radio frequency power is loaded on the load such as the radio frequency coil 11 .

[0112] It should be noted that C3 involved in the embodiments of the present application can be considered as the portion of the adjustable capacitor 12 connected between the second end of the RF coil 11 and ground. When the adjustable capacitor 12 is a capacitor connected only between the second end of the RF coil 11 and ground, adjusting C3 can be considered as adjusting the entire adjustable capacitor 12. When the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, adjusting C3 can be considered as adjusting the second sub-adjustable capacitor 122 of the adjustable capacitor 12. Of course, when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, adjusting the adjustable capacitor 12 requires adjusting both the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122.

[0113] Furthermore, in the case that the ignition is unsuccessful, the impedance value of the impedance adjusting member 12 is adjusted and the step of determining whether the ignition is successful is restarted.

[0114] As shown in FIG20 , still taking the impedance adjustment member as the adjustable capacitor 12 as an example, S105 . If the ignition is unsuccessful, the capacitance value of the adjustable capacitor 12 is reduced, that is, the impedance value of the adjustable capacitor is increased, and the step of determining whether the ignition is successful is restarted.

[0115] In this step, for example, the current capacitance value of the adjustable capacitor 12 can be multiplied by a preset coefficient to reduce the capacitance value after adjustment. The preset coefficient is less than 1, for example, the preset coefficient can be 0.9. The result after adjustment is equivalent to multiplying the current impedance value of the impedance adjuster by a preset coefficient greater than 1 to increase the impedance value after adjustment, as shown in FIG9 . Of course, the embodiment of the present application does not limit the specific size of the preset coefficient, as long as it is less than 1. Similarly, when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, to reduce the capacitance value of the adjustable capacitor 12, it is necessary to multiply the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 by a preset coefficient less than 1 (for example, 0.9) as the adjusted capacitance value for adjustment, which is equivalent to multiplying the impedance values ​​of the first sub-impedance adjuster and the second sub-impedance adjuster by a preset coefficient greater than 1 as the adjusted impedance value, as shown in FIG19 .

[0116] Referring to FIG. 9 , in one embodiment, still taking the impedance adjustment member as an example of an adjustable capacitor 12 , there may be at least one adjustable capacitor 12 , wherein:

[0117] Adjusting the adjustable capacitor 12 to a first preset capacitance value includes: adjusting the adjustable capacitor 12 to the first preset capacitance value so that the impedance value of the adjustable capacitor 12 is greater than the impedance value of the RF coil 11, for example, 1.2Z coilThat is, by adjusting the adjustable capacitor 12 to the first preset capacitance value, the impedance value thereof is correspondingly adjusted to the first preset impedance value, so that the impedance value of the adjustable capacitor 12 is greater than the impedance value of the RF coil 11;

[0118] Between loading RF power to the RF coil 11 and determining whether ignition is successful, the processor further performs: adjusting a first tuning capacitor and a second tuning capacitor of a matching device of the semiconductor process equipment to perform impedance matching so that RF power is at least loaded on the RF coil 11;

[0119] When the ignition is successful, the adjustable capacitor 12 is adjusted to the second preset capacitance value, including: increasing the capacitance of the adjustable capacitor 12 to the second preset capacitance value so that the impedance value of the adjustable capacitor 12 is greater than 0 and less than the impedance value of the RF coil 11, for example, 0.5Z coil That is, by adjusting the adjustable capacitor 12 to the second preset capacitance value, the impedance value thereof is correspondingly adjusted to the second preset impedance value, so that the impedance value of the adjustable capacitor 12 is less than the impedance value of the RF coil 11;

[0120] After adjusting the adjustable capacitor 12 to the second preset capacitance value, the processor further executes: adjusting the first tuning capacitor and the second tuning capacitor of the matching device to perform impedance matching so that the radio frequency power is at least loaded on the radio frequency coil 11;

[0121] In the event that ignition is unsuccessful, reducing the capacitance value of the adjustable capacitor 12 includes: multiplying the current capacitance value of the adjustable capacitor 12 by a preset coefficient (e.g., 0.9) as the capacitance value of the adjustable capacitor 12 after the reduction, and the preset coefficient is less than 1. In other words, in the event that ignition is unsuccessful, the impedance value of the adjustable capacitor 12 is increased by reducing the capacitance value of the adjustable capacitor 12. In particular, multiplying the current capacitance value of the adjustable capacitor 12 by the preset coefficient (e.g., 0.9) as the capacitance value of the adjustable capacitor 12 after the reduction is equivalent to multiplying the current impedance value of the adjustable capacitor 12 by a preset coefficient greater than 1 as the impedance value of the adjustable capacitor 12 after the increase. Referring to FIG. 19 , in another embodiment, the adjustable capacitor 12 may include, for example, two first sub-adjustable capacitors 121 and one second sub-adjustable capacitor 122 . The RF coil 11 may include at least two coil segments connected in series. Each first sub-adjustable capacitor 121 may be connected in series between two adjacent coil segments. The second sub-adjustable capacitor 122 is configured to be connected between the second end of the RF coil 11 and ground. As described above, more first sub-adjustable capacitors 121 may be provided.

[0122] Adjusting the adjustable capacitor 12 to a first preset capacitance value includes: adjusting the capacitance values ​​of the two first sub-adjustable capacitors 121 and the one second sub-adjustable capacitor 122 so that the impedance values ​​of the two first sub-adjustable capacitors 121 and the one second sub-adjustable capacitor 122 are greater than the impedance value of the RF coil 11, for example, 1.2Z coil That is, the capacitance values ​​of the two first sub-adjustable capacitors 121 and the one second sub-adjustable capacitor 122 are adjusted so that their respective impedance values ​​change accordingly, thereby making the impedance values ​​of the two first sub-adjustable capacitors 121 and the one second sub-adjustable capacitor 122 greater than the impedance value of the RF coil 11;

[0123] Between loading RF power to the RF coil 11 and determining whether ignition is successful, the processor further performs: adjusting a first tuning capacitor and a second tuning capacitor of a matching device of the semiconductor process equipment to perform impedance matching so that RF power is at least loaded on the RF coil 11;

[0124] When the ignition is successful, the adjustable capacitor 12 is adjusted to the second preset capacitance value, including: increasing the capacitance values ​​of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 so that the impedance values ​​of the two first sub-adjustable capacitors 121 are Z coil / 3, and the impedance value of the second sub-adjustable capacitor 122 is Z coil / 6, among which Z coil is the impedance value of the RF coil 11; more generally, the impedance value of each first sub-adjustable capacitor 121 is Z coil / n, and the impedance value of the second sub-adjustable capacitor 122 is Z coil / 2n, where n is the sum of the number of the first sub-adjustable capacitors 121 and the number of the second sub-adjustable capacitors 122 .

[0125] After adjusting the adjustable capacitor 12 to the second preset capacitance value, the processor further performs: adjusting the first tuning capacitor and the second tuning capacitor of the matching device to perform impedance matching, so that the radio frequency power is at least loaded on the radio frequency coil 11.

[0126] In the case where ignition is unsuccessful, reducing the capacitance value of the adjustable capacitor 12 includes: multiplying the current capacitance values ​​of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 by a preset coefficient as the capacitance value after the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 are reduced, and the preset coefficient is less than 1. That is, in the case where ignition is unsuccessful, the impedance value of the adjustable capacitor 12 is increased by reducing the capacitance value of the adjustable capacitor 12. Among them, multiplying the current capacitance values ​​of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 by a preset coefficient less than 1 as the capacitance value after the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 are reduced is equivalent to multiplying the current impedance values ​​of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 by a preset coefficient greater than 1 as the impedance value after the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 are increased.

[0127] It should be noted that in the above exemplary example, the L-type matcher performs impedance matching by adjusting the first tuning capacitor and the second tuning capacitor, but this is not restrictive. The matcher can also adopt other models. As long as the matcher can achieve impedance matching, it is within the scope of protection of this application.

[0128] The above embodiments of this application focus on the differences between the various embodiments. As long as the different technical features of the various embodiments are not contradictory, they can be combined to form more specific embodiments. Considering the simplicity of the text, they will not be repeated here.

[0129] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. An upper electrode device for a process chamber, characterized in that: The invention comprises a radio frequency coil and an impedance adjusting component, wherein the radio frequency coil is used to be wound around the outside of a shielding tube of the process chamber, and the shielding tube is used to be sleeved outside a plasma generating chamber of the process chamber; the impedance adjusting component is connected in series with the radio frequency coil, and the impedance adjusting component is used to be adjusted to different impedance values ​​in the ignition stage and the reaction stage of the process chamber.

2. The upper electrode device according to claim 1, characterized in that: The first end of the RF coil is used to be electrically connected to the RF power supply of the process chamber, and the second end of the RF coil is used to be grounded through the impedance adjustment member.

3. The upper electrode device according to claim 2, characterized in that: There is at least one impedance adjusting member, and the impedance value of the impedance adjusting member in the ignition stage is greater than Z coil , the Z coil is the impedance value of the RF coil, and the impedance value of the impedance adjusting member in the reaction stage is greater than 0 and less than Z coil ; or, The impedance value of the impedance adjusting member in the reaction stage is greater than 0.4Z coil And less than 0.6Z coil ;or, The impedance value of the impedance adjusting member in the reaction stage is equal to 0.5Z coil .

4. The upper electrode device according to claim 1, characterized in that: The first end of the RF coil is used to be electrically connected to the RF power supply of the process chamber, and the second end of the RF coil is used to be grounded. The impedance adjusting member includes at least one first sub-impedance adjusting member, and the RF coil includes at least two coil segments connected in series, and each of the first sub-impedance adjusting members is connected in series between two adjacent coil segments.

5. The upper electrode device according to claim 4, characterized in that: The impedance adjusting member further includes a second sub-impedance adjusting member, and the second sub-impedance adjusting member is used to be connected between the second end of the radio frequency coil and the ground.

6. The upper electrode device according to claim 5, characterized in that: In the ignition stage, the impedance values ​​of the first sub-impedance adjustment member and the second sub-impedance adjustment member are both greater than Z coil , the Z coil is the impedance value of the radio frequency coil; In the reaction stage, the impedance values ​​of the first sub-impedance adjusting element and the second sub-impedance adjusting element are both greater than 0 and less than Z coil .

7. The upper electrode device according to claim 5, characterized in that: There are a plurality of the first sub-impedance adjusting components, and the impedance values ​​of the first sub-impedance adjusting components are equal and greater than the impedance value of the second sub-impedance adjusting component.

8. The upper electrode device according to claim 5, characterized in that: The impedance value of the first impedance adjusting element is Z coil / n, the impedance value of the second impedance adjusting element is Z coil / 2n, wherein n is the sum of the number of the first sub-impedance adjusting components and the number of the second sub-impedance adjusting components.

9. The upper electrode device according to claim 5, characterized in that: The shielding tube is provided with a plurality of slits extending along the axial direction of the shielding tube, the plurality of slits are distributed at intervals in the circumferential direction of the shielding tube, and the first sub-impedance adjusting member and the second sub-impedance adjusting member are both distributed in a staggered manner with respect to the slits.

10. The upper electrode device according to claim 1, characterized in that: The upper electrode device also includes a driving mechanism, and the impedance adjustment member includes a first capacitor plate and a second capacitor plate. The driving mechanism is connected to at least one of the first capacitor plate and the second capacitor plate, and the driving mechanism is used to drive at least one of the first capacitor plate and the second capacitor plate to move, so as to adjust at least one of the distance and relative area between the first capacitor plate and the second capacitor plate to adjust the capacitance value of the impedance adjustment member.

11. The upper electrode device according to claim 1, characterized in that: The shielding cylinder is provided with a plurality of slits extending axially along the shielding cylinder, the plurality of slits are evenly spaced in the circumferential direction of the shielding cylinder, the width of the slits at the two axial ends is greater than the width at a predetermined position between the two ends, and the RF coil is wound around the outer circumferential side of the shielding cylinder and is located at a predetermined position of the slits in the axial direction.

12. The upper electrode device according to claim 1, characterized in that: The shielding tube is provided with a plurality of slits extending along the axial direction of the shielding tube, and the plurality of slits are evenly spaced in the circumferential direction of the shielding tube. The shielding tube is provided with a plurality of flared windows, and the plurality of flared windows are correspondingly connected with the ends of the plurality of slits along the axial direction, and the size of the plurality of flared windows in the circumferential direction of the shielding tube is larger than the size of the slits in the circumferential direction of the shielding tube.

13. The upper electrode device according to claim 1, characterized in that: The shielding cylinder comprises a plurality of grounding portions, wherein the plurality of grounding portions are located at the bottom end of the shielding cylinder and are evenly distributed along the circumferential direction of the shielding cylinder.

14. A process chamber, characterized in that: The invention comprises a plasma generating chamber, a process reaction chamber, a shielding tube and an upper electrode device according to any one of claims 1 to 13, wherein the process reaction chamber is connected with the plasma generating chamber.

15. The process chamber according to claim 14, characterized in that: The process chamber further comprises a shielding box, the plasma generating chamber, the shielding cylinder, the radio frequency coil and the impedance adjusting member are all arranged inside the shielding box, and the shielding cylinder is electrically connected to the ground of the shielding box.

16. The process chamber according to claim 15, characterized in that: The process chamber further includes a radio frequency power supply and a matcher, wherein the radio frequency power supply is electrically connected to the first end of the radio frequency coil through the matcher, and the radio frequency power supply and the matcher are located outside the shielding box and are installed on the shielding box.

17. A semiconductor process equipment, characterized in that: A process chamber comprising a controller and any one of claims 14 to 16, wherein the controller comprises a memory and a processor, the memory stores a computer program, and the processor performs the following steps according to the computer program: Adjusting the impedance adjusting member to a first preset impedance value; loading radio frequency power to the radio frequency coil, and determining whether ignition is successful; When the ignition is successful, the impedance adjustment member is adjusted to a second preset impedance value, and the second preset impedance value is smaller than the first preset impedance value.

18. The semiconductor process equipment according to claim 17, characterized in that: The processor further performs the following steps according to the computer program: In case the ignition is unsuccessful, the impedance value of the impedance adjusting member is increased and the step of determining whether the ignition is successful is restarted.

19. The semiconductor process equipment according to claim 17, characterized in that: The impedance adjusting member is at least one, wherein: The step of adjusting the impedance adjusting member to a first preset impedance value comprises: adjusting the impedance adjusting member to the first preset impedance value so that the impedance value of the impedance adjusting member is greater than the impedance value of the radio frequency coil; Between the step of loading the RF power to the RF coil and the step of determining whether the ignition is successful, the processor further executes: adjusting the matcher of the semiconductor process equipment to perform impedance matching so that the RF power is at least loaded on the RF coil; In the case of successful ignition, adjusting the impedance adjustment member to a second preset impedance value comprises: reducing the impedance value of the impedance adjustment member to the second preset impedance value, so that the impedance value of the impedance adjustment member is greater than 0 and less than the impedance value of the radio frequency coil; After adjusting the impedance adjusting member to a second preset impedance value, the processor further executes: adjusting the matcher to perform impedance matching so that the radio frequency power is at least loaded on the radio frequency coil; or The processor is also used to execute: in the case of unsuccessful ignition, increasing the impedance value of the impedance adjusting component, including: multiplying the current impedance value of the impedance adjusting component by a preset coefficient as the increased impedance value of the impedance adjusting component, wherein the preset coefficient is greater than 1.

20. The semiconductor process equipment according to claim 17, characterized in that: The impedance adjusting member includes a plurality of first sub-impedance adjusting members and a second sub-impedance adjusting member, the radio frequency coil includes at least two coil segments connected in series, each of the first sub-impedance adjusting members is connected in series between two adjacent coil segments, and the second sub-impedance adjusting member is used to be connected between the second end of the radio frequency coil and the ground. The step of adjusting the impedance adjusting member to a first preset impedance value comprises: adjusting the impedance values ​​of the first sub-impedance adjusting members and the second sub-impedance adjusting member so that the impedance values ​​of the first sub-impedance adjusting members and the second sub-impedance adjusting member are greater than the impedance value of the radio frequency coil; Between the step of loading the RF power to the RF coil and the step of determining whether the ignition is successful, the processor further executes: adjusting the matcher of the semiconductor process equipment to perform impedance matching so that the RF power is at least loaded on the RF coil; In the case of successful ignition, adjusting the impedance adjustment element to a second preset impedance value includes: reducing the impedance values ​​of the first sub-impedance adjustment elements and the second sub-impedance adjustment elements so that the impedance value of each of the first sub-impedance adjustment elements is Z coil / n, and the impedance value of the second impedance adjusting member is Z coil / 2n, where Z coil is the impedance value of the radio frequency coil, and n is the sum of the number of the first sub-impedance adjusting components and the number of the second sub-impedance adjusting components; After adjusting the impedance adjusting member to a second preset impedance value, the processor further executes: adjusting the matcher to perform impedance matching so that the radio frequency power is at least loaded on the radio frequency coil; or The processor is also used to execute: in the case of unsuccessful ignition, increasing the impedance value of the impedance adjusting element, including: multiplying the current impedance value of each of the first sub-impedance adjusting element and the second sub-impedance adjusting element by a preset coefficient as the increased impedance value of each of the first sub-impedance adjusting element and the second sub-impedance adjusting element, and the preset coefficient is greater than 1.

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