Process chamber and electrode arrangement therefor, semiconductor processing apparatus

Abstract

The application discloses a process chamber, an upper electrode device thereof and a semiconductor process equipment. The upper electrode device comprises a radio frequency coil (11) and an adjustable capacitor (12). The radio frequency coil (11) is used for being wound outside a shielding cylinder (70) of the process chamber, and the shielding cylinder (70) is used for being sleeved outside a plasma generating cavity (20) of the process chamber. The adjustable capacitor (12) is connected in series with the radio frequency coil (11), and the adjustable capacitor (12) is used for being adjusted to different capacitance values in an ignition stage and a reaction stage of the process chamber. The above scheme can solve the problems of ignition difficulty and plasma bombardment on a dielectric window, and can also relieve the problem of abnormal discharge caused by the adoption of a lifting structure of the radio frequency coil.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor equipment technology, specifically relating to a process chamber and its upper electrode device, and semiconductor process equipment. Background Technology

[0002] In inductively coupled plasma (ICP) devices, a radio frequency (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 generation chamber into plasma. During this process, the coupling of RF energy into the plasma generation chamber is primarily inductive, with capacitive coupling playing a secondary role. Due to capacitive coupling, after plasma particles are formed, the electric field generated by the RF coil couples into the plasma generation chamber, resulting in a significant potential difference between the RF coil and the plasma. This large potential difference accelerates the bombardment of the plasma generation chamber's dielectric window by the plasma in the sheath within the chamber, thus shortening the chamber's lifetime. To minimize this potential difference, the electric field coupled from the RF coil into the plasma generation chamber needs to be as small as possible.

[0003] However, ignition requires a large electric field coupled from a radio frequency coil into the plasma generating cavity during plasma generation. Failure to ignite results in no plasma formation. Conversely, successful ignition necessitates a high voltage from the radio frequency coil, creating a significant potential difference between the coil and the plasma, which in turn drives the plasma to bombard the dielectric window through the large electric field. Therefore, resolving the ignition difficulty and reducing plasma bombardment of the plasma generating cavity presents a difficult contradiction, and overcoming this contradiction is a crucial problem urgently requiring solutions from those skilled in the art. Summary of the Invention

[0004] This invention discloses a process chamber and its upper electrode device, as well as semiconductor process equipment, to solve the problem that related technologies cannot simultaneously address the difficulties in ignition and the bombardment of the dielectric window by plasma.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, embodiments of the present invention disclose an upper electrode device for a process chamber. The disclosed upper electrode device includes a radio frequency coil and an adjustable capacitor. The radio frequency coil is used to wind around the shielding cylinder of the process chamber, and the shielding cylinder is used to be fitted around the plasma generating cavity of the process chamber.

[0007] The adjustable capacitor is connected in series with the radio frequency coil, and the adjustable capacitor is used to be adjusted to different capacitance values ​​during the ignition and reaction phases of the process chamber.

[0008] Secondly, embodiments of the present invention disclose a process chamber, which includes a plasma generating chamber, a process reaction chamber, a shielding cylinder, and the upper electrode device described above, wherein the process reaction chamber is connected to the plasma generating chamber.

[0009] Thirdly, embodiments of the present invention disclose a semiconductor process apparatus, the disclosed semiconductor process apparatus including a controller and the process chamber described above, the controller including a memory and a processor, the memory storing a computer program, and the processor executing the following steps according to the computer program:

[0010] Adjust the adjustable capacitor to a first preset capacitance value;

[0011] Apply radio frequency power to the radio frequency coil and determine whether ignition is successful;

[0012] If ignition is successful, the adjustable capacitor is adjusted to a second preset capacitance value, which is greater than the first preset capacitance value.

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

[0014] The process chamber disclosed in this invention improves the structure of the upper electrode device by adding an adjustable capacitor with an adjustable capacitance value connected in series with the radio frequency coil. This allows the adjustable capacitor to be adjusted to different capacitance values ​​during the ignition and process stages. By adjusting the capacitance value of the adjustable capacitor, the voltage of the radio frequency coil can be adjusted. During the ignition stage, a higher voltage in the radio frequency coil results in a larger electric field coupled into the plasma generation chamber, making ignition easier and more successful. Simultaneously, during the process stage, adjusting the capacitance value of the adjustable capacitor further adjusts the voltage of the radio frequency coil, resulting in a lower voltage and a smaller electric field coupled into the plasma generation chamber, ultimately mitigating plasma bombardment of the dielectric window of the plasma generation chamber.

[0015] Therefore, it can be seen that the upper electrode device disclosed in the embodiments of the present invention can solve the difficult contradiction between ignition difficulty and reducing plasma bombardment of the dielectric window by adding an adjustable capacitor and changing the capacitance value of the adjustable capacitor during the ignition stage and the process stage. At the same time, there is no need to design the radio frequency coil as a lifting structure. The radio frequency coil can be fixedly wound outside the shielding cylinder, thereby avoiding the problem of abnormal discharge that is more likely to occur in the radio frequency coil lifting scheme, and thus avoiding the problem of easy damage to the corresponding components caused by abnormal discharge. Attached Figure Description

[0016] Figure 1 This is a partial structural schematic diagram of the process chamber disclosed in an embodiment of the present invention;

[0017] Figure 2 yes Figure 1 sectional view, Figure 1 and Figure 2 The process reaction chamber is not shown in any of the process chambers;

[0018] Figure 3 yes Figure 1 A partial structural diagram;

[0019] Figure 4 This is a schematic diagram of the structure of the shielding cylinder disclosed in an embodiment of the present invention;

[0020] Figure 5 and Figure 6 These are schematic diagrams of the radio frequency coil and plasma generating cavity involved in this invention.

[0021] Figure 7 yes Figure 1 The circuit diagram of the upper electrode device is shown below;

[0022] Figure 8 yes Figure 1 A schematic diagram showing the effect of the adjustable capacitor in the upper electrode device on the potential of the radio frequency coil;

[0023] Figure 9 This is a schematic diagram of an ignition process disclosed in an embodiment of the present invention;

[0024] Figure 10 This is a partial structural schematic diagram of another process chamber disclosed in an embodiment of the present invention, wherein, Figure 10 The process reaction chamber is not shown.

[0025] Figure 11 yes Figure 10 A partial structural diagram;

[0026] Figure 12 yes Figure 11 A partial structural diagram;

[0027] Figure 13 yes Figure 12 A partial structural diagram;

[0028] Figure 14 yes Figure 10 The circuit diagram of the upper electrode device is shown below;

[0029] Figure 15 and Figure 16 They are Figure 1 and Figure 10 The potential distribution diagram of the radio frequency coil of the upper electrode device during the ignition stage is shown.

[0030] Figure 17 and Figure 18 They are Figure 1 and Figure 10 The diagram shows the potential distribution of the RF coil in the upper electrode device during the manufacturing process.

[0031] Figure 19 This is a schematic diagram of another ignition process disclosed in an embodiment of the present invention;

[0032] Figure 20 This is a flowchart of the execution steps of a processor in a semiconductor process device disclosed in an embodiment of the present invention.

[0033] in, Figure 8 , Figure 9 and Figure 19 The coil in the text refers to radio frequency coil 11. Figure 7 , Figure 8 , Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 In this context, the "source end" refers to the first end of the RF coil 11, and the "end end" refers to the second end of the RF coil 11. Figure 9 and Figure 19 The power mentioned refers to radio frequency power.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10 - Upper electrode device; 11 - Radio frequency coil; 12 - Adjustable capacitor; 13 - Drive mechanism; 121 - First sub-adjustable capacitor; 122 - Second sub-adjustable capacitor;

[0036] 20-Plasma generating chamber, 30-RF power supply, 40-Matching unit, 50-Process gas input pipe, 60-Gas nozzle, 70-Shielding cylinder, 71-Gap, 72-Flanged window, 80-Shielding box. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] The technical solutions disclosed in the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] Please refer to Figures 1 to 19This invention discloses a process chamber. The disclosed process chamber is at least a part of a semiconductor process apparatus. The disclosed process chamber may include an upper electrode device 10, a plasma generation chamber 20, a radio frequency power supply 30, a matching device 40, a process gas input pipe 50, a gas nozzle 60, a shielding cylinder 70, a process reaction chamber, etc.

[0040] The upper electrode device 10 includes an RF coil 11. The first end of the RF coil 11 can be electrically connected to the RF power supply 30 via a matching adapter 40, which automatically performs impedance matching adjustment. Alternatively, the matching adapter 40 can be electrically connected to the first end of the RF coil 11 via an electrical connector strip for convenient electrical connection. Of course, the first end of the RF coil 11 can be directly electrically connected to the matching adapter 40.

[0041] The second end of the radio frequency coil 11 is used to connect to ground. Specifically, the radio frequency coil 11 can be used to connect directly to ground, or it can be connected to ground through other grounding components. This embodiment of the invention does not impose any limitations.

[0042] 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 nozzle 60 installed on the plasma generating chamber 20, and connected to the plasma generating chamber 20 through the gas nozzle 60. Process gas can flow out from the process gas source, and then enter the plasma generating chamber 20 along the process gas input pipe 50 and the gas nozzle 60, thereby preparing for the subsequent formation of plasma in the plasma generating chamber 20. The gas nozzle 60 can be structured to distribute the process gas so that the process gas is delivered to the plasma generating chamber 20 as uniformly as possible. The plasma generating chamber 20 can be a dielectric tube made of materials such as quartz or ceramic. The dielectric tube can be cylindrical or other shapes; this embodiment of the invention is not limited to any particular shape.

[0043] The shielding cylinder 70 provides shielding. The shielding cylinder 70 can be a Faraday cage. The shielding cylinder 70 is fitted around the plasma generating cavity 20 to provide a certain degree of shielding. The radio frequency coil 11 is wound around the shielding cylinder 70. When the radio frequency coil 11 is energized, it generates a magnetic field and an electric field. The shielding cylinder 70 hardly loses the magnetic field coupled to the plasma generating cavity 20, but it shields the electric field generated by the radio frequency coil 11, thus reducing the electric field coupled from the radio frequency coil 11 into the plasma generating cavity 20. In other words, the radio frequency coil 11 is wound not only around the shielding cylinder 70 but also around the plasma generating cavity 20.

[0044] In the specific operation process, the RF power supply 30 transmits RF power (which can be understood as RF energy) through the matching unit 40 to the RF coil 11, and finally to ground. Of course, if 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 to ground through the shielding box 80. During this process, the RF coil 11 couples a magnetic field and an electric field into the plasma generation chamber 20. The electric field is applied to the process gas that has been input into the plasma generation chamber 20, thereby causing the process gas to dissociate and form plasma, thus completing the ignition. The magnetic field determines the plasma distribution density, and the magnetic field is applied to the plasma to ensure that the plasma density meets the requirements. The process reaction chamber is connected to the plasma generation chamber 20. Plasma with the required density will enter the process reaction chamber from the plasma generation chamber 20 to participate in the process reaction. The process reaction chamber can be located below the plasma generation chamber 20 and connected to the plasma generation chamber 20.

[0045] As described above, the process gas needs to form plasma before participating in the process reaction. Accordingly, the process chamber disclosed in this embodiment of the invention needs to undergo an ignition stage and a reaction stage during operation. The reaction stage occurs after the ignition stage is completed; of course, the normal progress of the reaction stage requires successful ignition in the ignition stage.

[0046] The shielding cylinder 70 can shield a portion of the electric field of the radio frequency coil 11. Since the shielding cylinder 70 is grounded, its potential is low, resulting in a smaller potential difference between the generated plasma and the shielding cylinder 70. This, in turn, reduces the potential difference between the plasma and the dielectric window of the plasma generating cavity 20 (located between the shielding cylinder 70 and the plasma). This mitigates the impact of the plasma bombarding the dielectric window under the influence of the electric field, thereby extending the service life of the plasma generating cavity 20. Optionally, the shielding cylinder 70 can be installed within the shielding box 80 described later and electrically connected to it, ultimately grounded through the shielding box 80.

[0047] Before forming plasma, the process gas needs to be ignited; that is, the process chamber described above undergoes an ignition stage during operation. In developing this invention, the inventors discovered that while the shielding cylinder 70 effectively shields the plasma generation chamber 20 from plasma bombardment, the ignition stage requires the radio frequency coil 11 to increase capacitive coupling, thereby allowing more electric field to couple into the plasma generation chamber 20 to ignite the process gas. This requirement is difficult to achieve precisely because of the shielding function of the shielding cylinder 70. In other words, while the shielding cylinder 70 does alleviate plasma bombardment of the dielectric window, it leads to ignition difficulties, ultimately making successful ignition challenging. Conversely, to solve the ignition difficulty problem, the shielding cylinder 70 should be avoided as much as possible. Therefore, resolving the ignition difficulty and preventing plasma bombardment of the plasma generation chamber 20 presents a difficult contradiction to reconcile.

[0048] Based on this, the inventors improved the process chamber, enabling the RF coil 11 to rise and fall 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 changes the ignition distance (i.e., discharge distance) between the RF coil 11 and ground, making it easier to generate a larger voltage on the RF coil 11 for ignition, thus increasing the success rate of ignition. After successful ignition, the height of the RF coil 11 is lowered, bringing it closer to the process reaction chamber, thereby ensuring the efficiency of the process reaction.

[0049] However, the inventors further discovered that the current of the RF coil 11 is relatively large, and the electrical connection strip connecting the RF coil 11 to the matching unit 40 or the RF power supply 30 is generally wide and rigid. The RF coil 11 carries an extremely high voltage. If there is a loose connection between the electrical connection strip and the RF coil 11, it is easy to cause abnormal discharge at the contact point, which in turn causes damage to the components (RF coil 11, electrical connection strip) and process failure. In order to avoid abnormal discharge, the electrical connection strip and the RF coil 11 need to be connected in a good rigid contact manner. This determines that the RF coil 11 needs to be fixedly installed. Obviously, this determines that it is difficult to design the RF coil 11 as a movable structure that can be raised and lowered. Next, the voltage of the RF coil 11 is typically several kilovolts or even tens of thousands of volts, while the shielding cylinder 70 is grounded. To ensure coupling efficiency, the distance between the RF coil 11 and the shielding cylinder 70 is not large, only a few millimeters to tens of millimeters. Therefore, the withstand voltage design between the RF coil 11 and the shielding cylinder 70 requires special attention. Furthermore, the RF coil 11 is prone to abnormal discharge with the shielding cylinder 70 during the lifting and lowering process. Thus, the lifting and lowering design of the RF coil 11 has high requirements for withstand voltage design. Slight negligence can easily lead to arcing discharge between the lifting and lowering RF coil 11 and the shielding cylinder 70, resulting in damage to the components (RF coil 11 and shielding cylinder 70). Additionally, the lifting and lowering of the RF coil 11 takes a considerable amount of time and causes a change in the load impedance of the matching circuit 40. The matching circuit 40 needs to re-match its impedance, ultimately resulting in a longer ignition stage and lower throughput in the process chamber.

[0050] Based on the various problems listed above, the inventors of this invention have further improved the structure of the process chamber, so that the upper electrode device 10 involved in the embodiments of this invention may also include an adjustable capacitor 12.

[0051] The adjustable capacitor 12 is a capacitor whose capacitance value can be adjusted. In this embodiment of the invention, the adjustable capacitor 12 is connected in series with the radio frequency coil 11. The adjustable capacitor 12 is used to be adjusted to different capacitance values ​​during the ignition and reaction stages of the process chamber. In this case, during the ignition stage, the capacitance value of the adjustable capacitor 12 is adjusted so that after the matching device 40 performs impedance matching adjustment, the voltage of the radio frequency coil 11 can be adjusted to a higher voltage. This allows the electric field generated by the radio frequency coil 11 to still couple a larger electric field into the plasma generation chamber 20 even after being partially shielded by the shielding cylinder 70, thus making it easier to achieve successful ignition. After the ignition stage is completed and the process stage begins, in order to prevent the electric field generated by the RF coil 11 from being excessively coupled into the plasma generating cavity 20, the capacitance value of the adjustable capacitor 12 is further adjusted. This allows the matching device 40 to perform impedance matching adjustment, enabling the voltage of the RF coil 11 to be adjusted to a smaller voltage. As a result, after the electric field generated by the RF coil 11 is partially shielded by the shielding cylinder 70, the electric field that can be coupled into the plasma generating cavity 20 is already small, and the plasma will not be driven by a large electric field to bombard the plasma generating cavity 20.

[0052] Specifically, during the ignition phase, the capacitance of the adjustable capacitor 12 can be adjusted to a first capacitance value. The matching unit 40 performs impedance matching adjustment based on the first capacitance value to adjust the voltage of the RF coil 11 to a first voltage, which is greater than the ignition voltage. It should be noted that, in this paper, the ignition voltage refers to the voltage corresponding to successful ignition; this embodiment of the invention does not limit the specific value of the ignition voltage. During the reaction phase, the capacitance of the adjustable capacitor 12 is adjusted to a second capacitance value. The matching unit 40 performs impedance matching adjustment based on the second capacitance value to adjust the voltage of the RF coil 11 to a second voltage, which is less than the ignition voltage, thereby avoiding coupling a large electric field into the plasma generation cavity 20. Here, the first capacitance value is less than the second capacitance value.

[0053] In the process chamber disclosed in this embodiment of the invention, by improving the structure of the upper electrode device 10, an adjustable capacitor 12 with an adjustable capacitance value is added and connected in series with the radio frequency coil 11. This allows the adjustable capacitor 12 to be adjusted to different capacitance values ​​during the ignition and process stages. By adjusting the capacitance value of the adjustable capacitor 12, the voltage of the radio frequency coil 11 can be adjusted. This results in a higher voltage in the radio frequency coil 11 during the ignition stage, leading to a larger electric field coupled into the plasma generation cavity 20 (i.e., increased capacitive coupling resulting in a stronger electric field coupled into the plasma generation cavity 20), thus facilitating successful ignition. Simultaneously, during the process stage, the voltage of the radio frequency coil 11 can be adjusted by changing the capacitance value of the adjustable capacitor 12, resulting in a lower voltage in the radio frequency coil 11. This leads to a smaller electric field coupled into the plasma generation cavity 20 (i.e., reduced capacitive coupling resulting in a weaker electric field coupled into the plasma generation cavity 20), ultimately mitigating the impact of plasma bombardment on the dielectric window of the plasma generation cavity 20.

[0054] Therefore, it can be seen that the upper electrode device 10 disclosed in the embodiments of the present invention can solve the difficult contradiction between ignition difficulty and reducing plasma bombardment of the dielectric window by adding an adjustable capacitor 12 and changing the capacitance value of the adjustable capacitor 12 during the ignition stage and the process stage. At the same time, there is no need to design the radio frequency coil 11 as a lifting structure. The radio frequency coil 11 can be fixedly wound outside the shielding cylinder 70, thereby avoiding the problem that the lifting scheme of the radio frequency coil 11 is prone to abnormal discharge and the corresponding components are easily damaged.

[0055] As mentioned above, the adjustable capacitor 12 is connected in series with the RF coil 11. Specifically, there are several ways to connect the adjustable capacitor 12 and the RF coil 11 in series. In one optional scheme, 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 ground. The adjustable capacitor 12 can be connected between the second end of the RF coil 11 and ground, thereby achieving series connection with the RF coil 11. This design method, by connecting the adjustable capacitor 12 between the second end of the RF coil 11 and ground, can easily ensure the integrity of the RF coil 11 (i.e., the RF coil 11 can be made of a single piece of wire), while also minimizing the need for major modifications to the RF coil 11. In other words, it is only necessary to add an adjustable capacitor 12 between the second end and ground of the RF coil 11 in the process chamber of related technologies, which is a minor modification and easy to implement.

[0056] Furthermore, the adjustable capacitor 12 can be one or at least two; the number of adjustable capacitors 12 is not limited in this embodiment of the invention. Of course, when there are at least two adjustable capacitors 12 connected in series between the second terminal of the RF coil 11 and ground, these adjustable capacitors 12 can be connected in series or in parallel between the second terminal of the RF coil 11 and ground.

[0057] Specifically, there is one adjustable capacitor 12, and the RF coil 11 can be made from a single piece of wire wound together. The adjustable capacitor 12 is connected between the second end of the RF coil 11 and ground. The impedance value of the adjustable capacitor 12 during the ignition phase can be greater than Z. coil For example, 1.2Z coil The impedance of the adjustable capacitor 12 during the reaction phase can be greater than 0 and less than Z. coil Optionally, the impedance of the adjustable capacitor 12 during the reaction phase is greater than 0.4 Z. coil And less than 0.6Z coil In a further alternative scheme, the impedance of the adjustable capacitor 12 during the reaction phase is equal to 0.5Z. coil Among them, Z coil This represents the impedance value of the RF coil 11. This alternative solution more easily addresses both the difficulties in ignition and the problem of plasma bombardment of the plasma generation cavity 20. The following section combines... Figure 7 and Figure 8 Let me explain in detail.

[0058] exist Figure 7 and Figure 13 In the middle, the matcher (i.e. Figure 7 , Figure 9 , Figure 14 and Figure 19 The Match 40 in this paper can be a commercially available, mature, and fully automatic L-type matching device. The sensor inside the matching device 40 reads the RF voltage and current and calculates the impedance value. Through a control program, the capacitance value of the adjustable capacitor 12 is adjusted, thereby matching the impedance of the back end of the upper electrode device 10 with the impedance of the front end RF power supply 30. This ensures that as much RF power (or RF energy) as possible can be transmitted to the back end load of the upper electrode device 10 (the back end load includes the RF coil 11 and the adjustable capacitor 12). It should be noted that the matching device 40 in this paper serves the purpose of impedance matching, and its structure and working principle are known and mature technologies, which will not be elaborated upon here.

[0059] Please refer to this first. Figure 7 The inductance of RF coil 11 is L coilThe real impedance of the load, such as RF coil 11, is R. The adjustable capacitor 12 connected to the second terminal of RF coil 11 is C3. The first and second tuning capacitors of the matching circuit 40 are C1 and C2, respectively. These capacitors are used to adjust the impedance of the downstream load to the output impedance of the RF power supply 30 (e.g., 50Ω) to ensure maximum power transfer to the downstream load. Assume the current flowing into RF coil 11 is I, and the voltage at the source terminal (i.e., the first terminal of RF coil 11) is V. A voltage and current sensor is located at the output of the matching circuit 40 to monitor the potential at the source terminal of RF coil 11. The potential at the source terminal of RF coil 11 is:

[0060] V = I(R + Z) coil +Z c3 (1)

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

[0062]

[0063] 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 of the RF coil 11; the higher the current of the RF coil 11, the higher the plasma density. Adjusting the capacitance of the adjustable capacitor 12 (C3) at the second end of the RF coil 11, and then re-matching C1 and C2 via the matching device 40, results in almost no change in the current flowing through the RF coil 11, which does not affect the excited plasma density, but can alter the voltage distribution on the RF coil 11. By reducing the average and maximum potentials on the RF coil 11, capacitive coupling can be reduced, lowering the electric field strength within the sheath. This weakens the plasma's impact on the dielectric window after being accelerated by the electric field, thus mitigating the impact of plasma on the dielectric window of the plasma generation cavity 20.

[0064] If the structure of RF coil 11 remains unchanged, then the impedance Z of RF coil 11 is... coilThe current remains unchanged; changing the size of the adjustable capacitor (C3) 12 does not affect the current flowing through the RF coil 11. It should be noted that for impedance Z = R + jX, R is the real impedance, consuming active power, and X is the imaginary impedance, consuming reactive power. The power output of the RF power supply 30 is all active power. Process chambers (e.g., etching machines) generally use 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 R, changing the size of the adjustable capacitor (C3) 12 only changes the imaginary impedance X, without affecting the real impedance R, and therefore does not affect the current I. Therefore, the potential difference ΔV across the RF coil 11 is basically the same, which is denoted here as:

[0065] ΔV=I·jωL coil =2V0 (3)

[0066] Under the same RF power, the potential difference across RF coil 11 is 2V0. The effect of different capacitor values ​​(C3) on the potential distribution across RF coil 11 is as follows: Figure 8 As shown, the corresponding values ​​are as follows Figure 8 As shown in Table 1. It can be seen that in Z... C3 >Z coil At this time, both the average and maximum potentials on the radio frequency coil 11 are relatively large, resulting in the strongest electric field coupled into the plasma generation cavity 20, which is most conducive to ignition. In Z... C3 =0.5Z coil At this time, the average potential and the maximum potential on the radio frequency coil 11 are both at their minimum. At this time, the electric field coupled to the plasma generating cavity 20 is the weakest, and the plasma bombardment of the plasma generating cavity 20 in the sheath is the weakest.

[0067] Table 1

[0068]

[0069] Based on this characteristic, in case ⑥ of Table 1, the RF coil 11 has the highest average potential and the strongest electric field, which is conducive to ignition. The capacitance value of the adjustable capacitor 12 in case ⑥ can be used for gas ignition and dissociation of process gas to form plasma. In case ③ of Table 1, the RF coil 11 has the lowest average potential and the weakest electric field. The capacitance value of the adjustable capacitor 12 in case ③ is more suitable for the process reaction (i.e., more suitable for the reaction stage).

[0070] To better understand the ignition process, please refer to [reference needed]. Figure 9 Before applying RF power, adjust C3 to meet Z. C3 =1.2Z coil >Z coil Of course, only Z needs to be satisfied.C3 >Z coil That's it. Note: This example shows a value greater than 1; it 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 its capacitance range. Under this condition, the overall potential of the RF coil 11 is relatively high. After venting and pressurizing the chamber (i.e., plasma generation chamber 20), RF power is applied, and C1 and C2 of the Match (i.e., matching device 40) are adjusted to achieve impedance matching, so that the RF power is applied to the load such as the RF coil 11. At this time, the electric field formed by the RF coil 11 is relatively strong, which is conducive to ignition.

[0071] The method for determining successful ignition: The output of the Match module is equipped with a voltage and current sensor (i.e., the Sensor in the diagram). Initially, the static impedance voltage V1 at the moment of ignition and the voltage V2 after ignition are collected manually. Since V2 is significantly smaller than V1, a 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, ignition is considered successful. If ignition fails, the value of C3 is continuously reduced (for example, the current value of C3 is multiplied by 0.9 to obtain the adjusted capacitance value of C3), and matching is repeated until ignition is successful.

[0072] After successful ignition, C3 is readjusted so that its impedance value meets Z. C3 =0.5Z coil In this case, the overall potential of RF coil 11 is the lowest. Then Match adjusts C1 and C2 to perform impedance matching, so that the RF power is fully loaded on the load such as RF coil 11, and then proceeds to the process stage.

[0073] As described above, the first end of the RF coil 11 is used for electrical connection to the RF power supply 30 of the process chamber, and the second end of the RF coil 11 is used for grounding. In another alternative embodiment, 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 wire, but rather multiple separate wire segments (at least two segments). In this case, during the adjustment of the capacitance value of the adjustable capacitor 12, the capacitance value of the first sub-adjustable capacitor 121 can be adjusted to achieve the purpose of this invention.

[0074] For example, the radio frequency coil 11 may include two coil segments, and the first sub-adjustable capacitor 121 may be one and connected between the two coil segments.

[0075] 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. For example... Figures 9 to 12 As shown, there can be two first sub-adjustable capacitors 121, and the RF coil 11 can include three coil segments. The first sub-adjustable capacitors 121 can be two, and they are respectively connected between two adjacent coil segments.

[0076] Please refer to this again. Figures 9 to 12 In a further technical solution, the adjustable capacitor 12 may further include a second sub-adjustable capacitor 122, which is connected between the second terminal of the RF coil 11 and ground. During the adjustment of the capacitance value 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 to achieve the objective of this invention.

[0077] When the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, during the ignition phase, the impedance values ​​of both the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 can be greater than Z. coil For example, 1.2Z coil During the reaction phase, the impedance values ​​of both the first sub-tunable capacitor 121 and the second sub-tunable capacitor 122 can be greater than 0 and less than Z. coil .

[0078] In other embodiments, during the reaction phase, the impedance value of the first sub-tunable capacitor 121 can be Z. coil / n, the impedance value of the second sub-adjustable capacitor 122 can be Z. coil / 2n. This alternative scheme more easily addresses both the difficulties in ignition and the problem of plasma bombardment of the plasma generating cavity 20. Here, n is the sum of the number of the first sub-tunable capacitors 121 and the number of the second sub-tunable capacitors 122. Specifically, there are two first sub-tunable capacitors 121 and one second sub-tunable capacitor 122; in this case, n is 3. Correspondingly, during the reaction phase, the impedance value of the first sub-tunable capacitor 121 is Z. coil / 3, the impedance value of the second sub-adjustable capacitor 122 is Z. coil / 6. The following are combined Figures 10 to 18 To explain.

[0079] like Figure 12 and Figure 13 As shown, the RF coil 11 is divided into three coil segments, and the total inductance of the RF coil 11 is L. coil It can be divided into 3 equal parts, and the inductance of each segment is L. coil / 3. The real impedance of the load, such as the RF coil 11, is R. The second sub-adjustable capacitor 122 at the second end of the RF coil 11 is C3. The two first sub-adjustable capacitors 121 connected in series with the RF coil 11 correspond to C4 and C5 in the schematic diagram, respectively. The first and second tuning capacitors in the fully automatic matching circuit (Match) 40 are C1 and C2, respectively, used to adjust the impedance of the downstream load to the output impedance of the RF power supply 30 (e.g., 50Ω) to ensure maximum power transfer to the downstream load. Assume 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 (e.g., ...) at the output of the Match. Figure 14 The sensor in the RF coil 11 can be used to monitor the potential at the source terminal of the RF coil 11. The potential at the source terminal of the RF coil 11 is:

[0080] V = I(R + Z) coil +Z3+Z4+Z5) (4)

[0081] Among them, the impedance Z of the radio frequency coil 11 coil =jωL coil The impedance of the second adjustable capacitor (C3) 122 The impedance of the capacitor (i.e., a first sub-adjustable capacitor 121) C4 connected in series with the coil segment The impedance of the capacitor C5 connected in series with the coil segment (i.e., another first sub-adjustable capacitor 121) The angular frequency ω = 2πf, where f is the frequency of the output signal of the RF power supply 30. After the Match satisfies the impedance matching condition, the output power of the RF power supply 30 satisfies Power = I. 2 R, then the potential at the source terminal of RF coil 11 is:

[0082]

[0083] 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 of the RF coil 11; the higher the current of the RF coil 11, the higher the plasma density. Adjusting the capacitance values ​​of the second sub-regulating capacitor (C3) 122 and the two first sub-regulating capacitors (C4 and C5) 121 at the rear end of the RF coil 11, and after Match adjustment of C1 and C2, re-matching, the current flowing through the RF coil 11 remains almost unchanged and does not affect the excited plasma density, but it can change the voltage distribution on the RF coil 11. By reducing the average potential and maximum potential on the RF coil 11, capacitive coupling can be reduced, and the electric field in the sheath region can be reduced, thus weakening the plasma's accelerated bombardment of the plasma generation cavity 20 by the electric field.

[0084] If the structure of RF coil 11 remains unchanged, then the impedance Z of RF coil 11 is... coilThe values ​​of C3, C4, and C5 remain unchanged; changing the values ​​of C3, C4, and C5 does not affect the current flowing through the RF coil 11, so the potential difference ΔV across the RF coil 11 remains essentially the same, which is denoted here as:

[0085] ΔV=I·jωL coil =2V0 (6)

[0086] At the same RF power, the potential difference across the two ends of RF coil 11 is 2V0. Figure 15 In the structure shown, the RF coil 11 is divided into three segments, with a potential drop of 2V0 / 3 ≈ 0.67V0 for each segment. When the adjustable capacitor 12 is only distributed between the second terminal of the RF coil 11 and ground during the ignition phase, the potential distribution of the RF coil 11 is as follows: Figure 15 As shown, 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.

[0087] When the adjustable capacitor 12, including two first sub-adjustable capacitors 121 and a second sub-adjustable capacitor 122, is in the ignition stage, the potential distribution of the RF coil 11 is as follows: Figure 16 As shown, 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 and Z, respectively. C4 Z C5 Among them, Z C4 =Z C5 =1.2Z coil Therefore, the maximum potential amplitude on the RF coil 11 is 5.86V0. This shows that compared to... Figure 15 The structure of the upper electrode device 10 shown is as follows: Figure 16 The structure shown enables the radio frequency coil 11 to obtain a higher potential at the moment of ignition, and the electric field coupled to the plasma generation cavity 20 is stronger, which is more conducive to ignition and completion of ignition (i.e., completion of ignition).

[0088] When the adjustable capacitor 12 is only distributed between the second terminal of the RF coil 11 and ground, the potential distribution of the RF coil 11 during the manufacturing process is as follows: Figure 17 As shown, the impedance value Z of the adjustable capacitor 12 of the RF coil 11 is... C3 =0.5Z coil Therefore, the maximum potential amplitude on the RF coil 11 is V0. While the adjustable capacitor 12, comprising two first sub-adjustable capacitors 121 and a second sub-adjustable capacitor 122, is still in the manufacturing stage, the potential distribution of the RF coil 11 is as follows: Figure 18As shown, the impedance value Z of the second sub-adjustable capacitor 122 of the RF coil 11 is... C3 =Z coil / 6, the impedance values ​​of the two first sub-adjustable capacitors 121 are respectively Z C4 Z C5 Among them, Z C4 =Z C5 =Z coil / 3, then the maximum potential amplitude on RF coil 11 is V0 / 3. Compared to Figure 17 The structure shown, Figure 18 The structure shown enables the RF coil 11 to obtain a lower potential during the process, thereby making the electric field coupled from the RF coil 11 to the plasma generating cavity 20 weaker, which is more conducive to keeping the plasma generating cavity 20 less damaged during the process.

[0089] Based on this characteristic, an ignition process can be designed as follows: Figure 19 As shown. Before applying power, adjust C3, C4, and C5 to satisfy 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 pressurizing the chamber (i.e., the plasma generation chamber 20), RF power is applied, and the impedance matching of C1 and C2 of the Match is adjusted so that the RF power is applied to the load such as the RF coil 11. At this time, the electric field coupled from the RF coil 11 to the plasma generation chamber 20 is relatively strong, which is conducive to ignition.

[0090] The method for determining successful ignition: The output of the Match module is equipped with a voltage and current sensor (i.e., the Sensor in the diagram). Initially, the voltage V1 at the moment of ignition and the voltage V2 after successful ignition are collected manually. Since V2 is significantly smaller than V1, a 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, ignition is considered successful. If ignition fails, the values ​​of C3, C4, and C5 are continuously reduced (for example, the current values ​​of C3, C4, and C5 are multiplied by 0.9 to obtain the adjusted capacitance values ​​of C3, C4, and C5), and the matching is re-performed until successful ignition.

[0091] After successful ignition, C3, C4, and C5 are readjusted to make the impedance value Z of C3 equal to that of C3. 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 =ZC5 =Z coil / 3, under this condition, the overall potential of RF coil 11 is at its lowest. Then Match adjusts C1 and C2 to perform impedance matching, so that the RF power is fully reloaded on the load such as RF coil 11, thereby completing ignition and entering the process stage.

[0092] In this embodiment of the invention, there are various ways to adjust the capacitance value of the adjustable capacitor 12. Of course, any capacitor capable of adjusting its capacitance value can be used as the adjustable capacitor 12. In an optional embodiment, the upper electrode device 10 disclosed in this invention 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 and second capacitor plates. The driving mechanism 13 is used to drive at least one of the first and second capacitor plates to move, thereby adjusting at least one of the distance and relative area between the first and second capacitor plates to adjust the capacitance value of the adjustable capacitor 12. For example, the driving mechanism 13 is connected to the first or second capacitor plate via a power connection shaft, thereby adjusting the rotation or movement of the first or second capacitor plate to achieve the purpose of adjusting the capacitance value. By using the drive mechanism 13 to adjust the capacitance value of the adjustable capacitor 13, the voltage of the RF coil 11 can be adjusted more quickly. Compared with the adjustment of the RF coil 11 by raising and lowering, the method of using the drive mechanism 13 in conjunction with the adjustable capacitor 12 can achieve successful ignition more quickly, thereby improving production capacity.

[0093] Of course, when the adjustable capacitor 12 includes a first sub-adjustable capacitor 121, the process chamber can be configured with a corresponding drive mechanism for the first sub-adjustable capacitor 121, so that the drive 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 to move. When the adjustable capacitor 12 includes a second sub-adjustable capacitor 122, the process chamber can also be configured with a corresponding drive mechanism for the second sub-adjustable capacitor 122, so that the drive 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 to move.

[0094] As described above, the shielding cylinder 70 can have various structures, and it is a hollow cylindrical component. Specifically, the shielding cylinder 70 can have multiple slits 71 spaced apart along its circumference. These slits 71 can be evenly distributed along the circumference of the shielding cylinder 70, which facilitates the more uniform coupling of a magnetic field through the shielding cylinder 70 into the plasma generating cavity 20, thereby improving the quality of the plasma generated within the plasma generating cavity 20 and ensuring it meets process requirements. The number of slits 71 can be six, four, or eight. This embodiment of the invention does not limit the specific number of slits 71.

[0095] The width of each part of the slit 71 can be equal. In other embodiments, the width at both ends of the slit 71 can be greater than the width of the middle part of the slit 71, and the RF coil 11 is wound around the outside of the middle part of the slit 71. As mentioned above, since the adjustable capacitor 12 can adjust the voltage distribution of the RF coil 11, the voltage on the RF coil 11 can be larger during the ignition stage, thereby enabling the RF coil 11 to couple to a larger electric field in the plasma generating cavity 20. Ultimately, even if the width of the slit 71 is small, ignition can still be easily ensured. In this optional embodiment, winding the RF coil 11 around the narrower middle part of the slit 71 allows the electric field of the RF coil 11 to be better shielded during the process stage, minimizing the coupling of the electric field into the plasma generating cavity 20 during the process stage, while also ensuring that the magnetic field is coupled from the shielding cylinder 70 into the plasma generating cavity 20 without damage.

[0096] Of course, since the radio frequency coil 11 is wound in the middle part of the slit 71, and considering the magnetic field distribution of the radio frequency coil 11, the width of both ends of the slit 71 is relatively large, making it easier for the magnetic field generated by the radio frequency coil 11 to couple into the plasma generating cavity 20.

[0097] In a further technical solution, the shielding cylinder 70 may also have multiple flared windows 72, which are connected one-to-one with the ends of the multiple gaps 71. The dimensions of the multiple flared windows 72 in the width direction of the gaps 71 are larger than the width of the corresponding gaps 71. In this case, since the bottom end of the shielding cylinder 70 is used for grounding, the opening at the bottom end of the shielding cylinder 70 is relatively easy to block (for example, it is easy to block by the shielding box 80 described later). The flared windows 72 can ensure that the magnetic field generated by the radio frequency coil 11 is sufficiently coupled into the plasma generating cavity 20 through the flared windows 72, thereby ensuring the inductive coupling effect.

[0098] As described above, the shielding cylinder 70 is used for grounding, thereby ensuring a low potential of the shielding cylinder 70, reducing the potential difference between the shielding cylinder 70 and the plasma, and thus preventing the plasma from bombarding the plasma generating cavity 20. In a preferred embodiment, the shielding cylinder 70 may include multiple grounding parts. The multiple grounding parts are located at the ends of the shielding cylinder 70 and can be evenly distributed along the circumference of the shielding cylinder 70. Designing multiple grounding parts evenly distributed in the circumferential direction enables the shielding cylinder 70 to adopt multi-point symmetrical grounding, thereby achieving more balanced grounding and ultimately ensuring the symmetry of the return path, thus ensuring the uniformity of the electromagnetic field coupled into the plasma generating cavity 20. The multiple grounding parts can be located at the lower bottom end of the shielding cylinder 70 or at the higher top end of the shielding cylinder 70; this embodiment of the invention is not limited to these locations.

[0099] Of course, as mentioned 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 cylinder 70 has multiple gaps 71 spaced apart along the circumference of the shielding cylinder 70, in this case, the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 may be opposite to the gaps 71, which can easily cause angular asymmetry of the electromagnetic field. Based on this, in an optional solution, the first sub-adjustable capacitor 121 can be staggered with the gaps 71. Of course, when the adjustable capacitor 12 includes a second sub-adjustable capacitor 122, the second sub-adjustable capacitor 122 can also be staggered with the gaps 71, such as... Figure 10 and Figure 11 As shown. This staggered distribution method almost eliminates the possibility of process result eccentricity caused by the discontinuity of RF coil 11.

[0100] The process chamber disclosed in this embodiment of the invention may further include a shielding box 80, which is used for grounding. The second end of the radio frequency coil 11 is electrically connected to the shielding box 80, thereby achieving grounding. The plasma generating chamber 20, the shielding cylinder 70, the radio frequency coil 11, and the adjustable capacitor 12 can be disposed within the shielding box 80, thereby being protected by the shielding box 80, and at the same time, preventing interference from magnetic fields that may exist in the external environment on the magnetic field generated by the radio frequency coil 11. The shielding cylinder 70 is electrically connected to the shielding box 80, thereby achieving grounding. In this embodiment of the invention, both the shielding cylinder 70 and the shielding box 80 can be made of metal.

[0101] In the case where the process chamber includes a drive mechanism 13, such as Figure 1 and Figure 2 As shown, in a preferred 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 mitigate the adverse effects of the drive mechanism 13 being located inside the shielding box 80 on the magnetic field generated by the RF coil 11.

[0102] In a further technical solution, the RF power supply 30 and the matching unit 40 can be located outside the shielding box 80 and mounted on the shielding box 80. In this case, the shielding box 80 can also provide mounting positions for the RF power supply 30 and the matching unit 40. Of course, the RF power supply 30 and the matching unit 40 are located outside the shielding box 80, thereby avoiding adverse effects on the components inside the shielding box 80.

[0103] Based on the process chamber disclosed in the embodiments of the present invention, the present invention further discloses a semiconductor process apparatus, which includes a controller and the process chamber described in any of the above embodiments. The controller includes a memory and a processor. The memory stores a computer program. Figure 20 As shown, the processor performs the following steps according to the computer program:

[0104] S101. Adjust the adjustable capacitor 12 to the first preset capacitance value.

[0105] In an alternative embodiment, where the adjustable capacitor 12 is connected only between the second terminal of the RF coil 11 and ground, in this step, the capacitance value of the adjustable capacitor 12 can be adjusted to a first preset capacitance value, such that the impedance value of the adjustable capacitor 12 is greater than Z. coil For example, 1.2Z coil This results in the RF coil 11 having a higher potential after RF power is applied.

[0106] In another alternative scheme, when the adjustable capacitor 12 includes the two first sub-adjustable capacitors 121 and one second sub-adjustable capacitor 122 mentioned above, this step can adjust 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 to a 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 both be greater than Z. coil For example, 1.2Z coil This results in a higher potential for the RF coil 11 after RF power is applied.

[0107] S102. Apply radio frequency power to radio frequency coil 11.

[0108] Of course, before applying the RF power, process gas needs to be introduced into the plasma generating chamber 20 and the gas pressure inside the plasma generating chamber 20 needs to be controlled. After applying the RF power, the matching unit 40 automatically adjusts its own C1 (i.e., the first tuning capacitor of the matching unit 40) and C2 (i.e., the second tuning capacitor of the matching unit 40) to perform impedance matching, so that the RF power is applied to the load such as the RF coil 11.

[0109] S103. Determine whether ignition was successful.

[0110] S104. If ignition is successful, adjust the adjustable capacitor 12 to the second preset capacitor value.

[0111] In an alternative embodiment, where the adjustable capacitor 12 is connected only between the second terminal of the RF coil 11 and ground, this step allows the capacitance value of the adjustable capacitor (C3) 12 to be adjusted to a second preset capacitance value, resulting in an impedance value of 0.5Z for the adjustable capacitor 12. coil This results in a lower potential for the radio frequency coil 11. The second preset capacitance value is greater than the first preset capacitance value.

[0112] In another alternative scheme, when the adjustable capacitor 12 includes the two first sub-adjustable capacitors 121 and one second sub-adjustable capacitor 122 described above, this step can adjust 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 respectively, so that the impedance value of the second sub-adjustable capacitor 122 is Z. coil / 6. The impedance values ​​of both first sub-adjustable capacitors 121 can be Z. coil / 3, which results in a lower potential for the RF coil 11 after RF power is applied.

[0113] Of course, after S104, the matching unit 40 can be controlled to automatically adjust its own C1 and C2 for impedance matching, so that the RF power is applied to the load such as the RF coil 11.

[0114] It should be noted that C3 in this embodiment of the invention can be considered as the portion of the adjustable capacitor 12 connected between the second terminal of the RF coil 11 and ground. When the adjustable capacitor 12 is only connected between the second terminal of the RF coil 11 and ground, adjusting C3 can be considered as adjusting the adjustable capacitor 12 as a whole. 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 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.

[0115] Further, it may include:

[0116] S105. If ignition fails, reduce the capacitance value of the adjustable capacitor 12 and restart the process of determining whether ignition was successful.

[0117] This step, for example, can multiply the current capacitance value of adjustable capacitor 12 by a preset coefficient to obtain the adjusted capacitance value for reduction. The preset coefficient is less than 1; for example, the preset coefficient could be 0.9. Figure 9 As shown, the specific value of the preset coefficient is not limited in this embodiment of the invention, 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, the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 need to be multiplied by a preset coefficient less than 1 (e.g., 0.9) respectively to obtain the adjusted capacitance value. Figure 19 As shown.

[0118] Please refer to Figure 9In one alternative embodiment, the adjustable capacitor 12 can be at least one, wherein:

[0119] 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. coil ;

[0120] Between applying RF power to RF coil 11 and determining whether ignition is successful, the processor also performs the following: adjusting the first and second tuning capacitors of the matching unit of the semiconductor process equipment for impedance matching so that RF power is applied to at least RF coil 11.

[0121] If ignition is successful, the adjustable capacitor 12 is adjusted to a second preset capacitance value, including: increasing the capacitance value 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 ;

[0122] After adjusting the adjustable capacitor 12 to the second preset capacitance value, the processor also performs the following: adjusting the first and second tuning capacitors of the matching unit for impedance matching so that the RF power is at least applied to the RF coil 11.

[0123] If ignition fails, reduce the capacitance value of the adjustable capacitor 12, including multiplying the current capacitance value of the adjustable capacitor 12 by a preset coefficient (e.g., 0.9) to obtain the reduced capacitance value of the adjustable capacitor 12. The preset coefficient is less than 1.

[0124] Please refer to Figure 19 In another alternative scheme, 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 used to connect between the second end of the RF coil 11 and ground. As mentioned above, more first sub-adjustable capacitors 121 may be provided.

[0125] 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 ;

[0126] Between applying RF power to RF coil 11 and determining whether ignition is successful, the processor also performs the following: adjusting the first and second tuning capacitors of the matching unit of the semiconductor process equipment for impedance matching so that RF power is applied to at least RF coil 11.

[0127] If 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 value of the two first sub-adjustable capacitors 121 is Z. coil / 3, and the impedance value of the second sub-adjustable capacitor 122 is Z. coil / 6, where Z coil Z 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.

[0128] After adjusting the adjustable capacitor 12 to the second preset capacitance value, the processor also performs the following: adjusting the first and second tuning capacitors of the matching unit for impedance matching so that the RF power is at least applied to the RF coil 11.

[0129] If ignition fails, the capacitance value of the adjustable capacitor 12 is reduced, including multiplying the current capacitance values ​​of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 by a preset coefficient to obtain the reduced capacitance values ​​of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122, where the preset coefficient is less than 1.

[0130] The above embodiments of the present invention focus on describing 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. For the sake of brevity, they will not be described in detail here.

[0131] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. An upper electrode device for a process chamber, characterized in that, The device includes a radio frequency coil (11) and an adjustable capacitor (12). The radio frequency coil (11) is used to wind around the shielding cylinder (70) of the process chamber. The shielding cylinder (70) is used to fit around the plasma generating chamber (20) of the process chamber and has multiple slits (71) spaced apart along the circumferential direction of the shielding cylinder (70). The adjustable capacitor (12) is connected in series with the radio frequency coil (11) and is used to be adjusted to different capacitance values ​​during the ignition stage and the reaction stage of the process chamber. The adjustable capacitor (12) includes at least one first sub-adjustable capacitor (121), and the radio frequency coil (11) includes at least two coil segments connected in series. Each of the first sub-adjustable capacitors (121) is connected in series between two adjacent coil segments and is staggered from the gap (71).

2. The upper electrode device according to claim 1, characterized in that, The adjustable capacitor (12) is at least one, and the impedance value of the adjustable capacitor (12) during the ignition phase is greater than Z. coil The Z coil The impedance value of the radio frequency coil (11) is given, and the impedance value of the adjustable capacitor (12) during the reaction phase is greater than 0 and less than Z. coil ;or, The impedance of the adjustable capacitor (12) during the reaction phase is greater than 0.4Z. coil And less than 0.6Z coil ;or, The impedance of the adjustable capacitor (12) during the reaction phase is equal to 0.5 Z. coil .

3. The upper electrode device according to claim 1, characterized in that, The first end of the radio frequency coil (11) is used to be electrically connected to the radio frequency power supply (30) of the process chamber, and the second end of the radio frequency coil (11) is used to be grounded.

4. The upper electrode device according to claim 3, characterized in that, The adjustable capacitor (12) also includes a second sub-adjustable capacitor (122), which is used to connect between the second end of the radio frequency coil (11) and ground.

5. The upper electrode device according to claim 4, characterized in that, During the ignition phase, the impedance values ​​of both the first sub-adjustable capacitor (121) and the second sub-adjustable capacitor (122) are greater than Z. coil The Z coil The impedance value of the radio frequency coil (11); During the reaction phase, the impedance values ​​of both the first sub-tunable capacitor (121) and the second sub-tunable capacitor (122) are greater than 0 and less than Z. coil .

6. The upper electrode device according to claim 5, characterized in that, 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).

7. The upper electrode device according to claim 4, characterized in that, The impedance value of the first sub-adjustable capacitor (121) is Z. coil / n, 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 capacitor (121) and the number of the second sub-adjustable capacitor (122).

8. The upper electrode device according to claim 4, characterized in that, The second sub-adjustable capacitor (122) is misaligned with the gap (71).

9. The upper electrode device according to claim 1, characterized in that, The upper electrode device (10) further includes a driving mechanism (13). The adjustable capacitor (12) includes a first capacitor plate and a second capacitor plate. The driving mechanism (13) is 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).

10. The upper electrode device according to claim 1, characterized in that, The shielding cylinder (70) is provided with a plurality of slits (71) spaced apart along the circumferential direction of the shielding cylinder (70). The plurality of slits (71) are evenly distributed in the circumferential direction. The width of the two ends of the slits (71) is greater than the width of the middle part of the slits (71). The radio frequency coil (11) is wound around the outside of the middle part.

11. The upper electrode device according to claim 10, characterized in that, The shielding cylinder (70) has multiple flared windows (72), which are connected to the ends of multiple gaps (71) in a one-to-one correspondence. The dimensions of the multiple flared windows (72) in the width direction of the gaps (71) are greater than the width of the gaps (71).

12. The upper electrode device according to claim 1, characterized in that, The shielding cylinder (70) includes multiple grounding parts, which are located at the bottom end of the shielding cylinder (70) and are evenly distributed along the circumference of the shielding cylinder (70).

13. A process chamber, characterized in that, It includes a plasma generating chamber (20), a process reaction chamber, a shielding cylinder (70), and an upper electrode device (10) according to any one of claims 1 to 12, wherein the process reaction chamber is connected to the plasma generating chamber (20).

14. The process chamber according to claim 13, characterized in that, The process chamber also includes a shielding box (80), the plasma generating chamber (20), the shielding cylinder (70), the radio frequency coil (11) and the adjustable capacitor (12) are all located inside the shielding box (80), and the shielding cylinder (70) is grounded and electrically connected to the shielding box (80).

15. The process chamber according to claim 14, characterized in that, The process chamber also includes an RF power supply (30) and a matching device (40). The RF power supply (30) is electrically connected to the first end of the RF coil (11) through the matching device (40). The RF power supply (30) and the matching device (40) are located outside the shielding box (80) and are installed on the shielding box (80).

16. A semiconductor process apparatus, characterized in that, The system includes a controller and a process chamber according to any one of claims 13 to 15, the controller including a memory and a processor, the memory storing a computer program, the processor performing the following steps according to the computer program: Adjust the adjustable capacitor (12) to the first preset capacitance value; Apply radio frequency power to the radio frequency coil (11) and determine whether ignition is successful; If ignition is successful, the adjustable capacitor (12) is adjusted to a second preset capacitor value, which is greater than the first preset capacitor value.

17. The semiconductor process equipment according to claim 16, characterized in that, The processor, according to the computer program, further performs the following steps: If ignition fails, reduce the capacitance value of the adjustable capacitor (12) and restart the step of determining whether ignition is successful.

18. The semiconductor process equipment according to claim 17, characterized in that, The adjustable capacitor (12) is at least one, wherein: The step of adjusting the adjustable capacitor (12) to a first preset capacitance value includes: adjusting the adjustable capacitor (12) to a first preset capacitance value so that the impedance value of the adjustable capacitor (12) is greater than the impedance value of the radio frequency coil (11). Between loading radio frequency power onto the radio frequency coil (11) and determining whether ignition is successful, the processor also performs the following: adjusting the first and second tuning capacitors of the matching unit of the semiconductor process equipment for impedance matching so that the radio frequency power is loaded onto the radio frequency coil (11) at least. When ignition is successful, adjusting the adjustable capacitor (12) to the second preset capacitance value includes: increasing the capacitance value 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 radio frequency coil (11). After adjusting the adjustable capacitor (12) to the second preset capacitance value, the processor further performs the following: adjusting the first tuning capacitor and the second tuning capacitor of the matching unit for impedance matching so that the radio frequency power is at least applied to the radio frequency coil (11); The step of reducing the capacitance value of the adjustable capacitor (12) when ignition fails includes: multiplying the current capacitance value of the adjustable capacitor (12) by a preset coefficient to obtain the reduced capacitance value of the adjustable capacitor (12), wherein the preset coefficient is less than 1.

19. The semiconductor process equipment according to claim 17, characterized in that, The adjustable capacitor (12) includes a plurality of first sub-adjustable capacitors (121) and a second sub-adjustable capacitor (122). The radio frequency coil (11) includes at least two coil segments connected in series. Each of the first sub-adjustable capacitors (121) is connected in series between two adjacent coil segments. The second sub-adjustable capacitor (122) is used to connect between the second terminal of the radio frequency coil (11) and ground. The step of adjusting the adjustable capacitor (12) to a first preset capacitance value includes: adjusting the capacitance values ​​of a plurality of first sub-adjustable capacitors (121) and a second sub-adjustable capacitor (122) so that the impedance values ​​of each of the first sub-adjustable capacitors (121) and the second sub-adjustable capacitor (122) are greater than the impedance value of the radio frequency coil (11). Between loading radio frequency power onto the radio frequency coil (11) and determining whether ignition is successful, the processor also performs the following: adjusting the first and second tuning capacitors of the matching unit of the semiconductor process equipment for impedance matching so that the radio frequency power is loaded onto the radio frequency coil (11) at least. When ignition is successful, adjusting the adjustable capacitor (12) to a second preset capacitance value includes: increasing the capacitance values ​​of multiple first sub-adjustable capacitors (121) and second sub-adjustable capacitors (122) so that 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 Z coil The impedance value of the radio frequency coil (11) is n, and n is the sum of the number of the first sub-adjustable capacitor (121) and the number of the second sub-adjustable capacitor (122). After adjusting the adjustable capacitor (12) to the second preset capacitance value, the processor further performs the following: adjusting the first tuning capacitor and the second tuning capacitor of the matching unit for impedance matching so that the radio frequency power is at least applied to the radio frequency coil (11); The method of reducing the capacitance value of the adjustable capacitor (12) when ignition fails includes: multiplying the current capacitance value of each of the first sub-adjustable capacitors (121) and the second sub-adjustable capacitors (122) by a preset coefficient to obtain the reduced capacitance value of each of the first sub-adjustable capacitors (121) and the second sub-adjustable capacitors (122), wherein the preset coefficient is less than 1.

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