Process chamber, upper electrode device thereof and semiconductor process equipment

Abstract

The invention discloses a process chamber, an upper electrode device thereof and semiconductor process equipment. Wherein 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 arranged outside a plasma generation cavity (20) of the process chamber in a sleeving mode; 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. According to the scheme, the problems of ignition difficulty and bombardment of plasma on the dielectric window can be solved, and meanwhile the problem that abnormal discharge is likely to be caused by the fact that the radio frequency coil adopts a lifting structure can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and particularly relates to a process chamber, an upper electrode device thereof, and a semiconductor process equipment. Background Art

[0002] In an inductively coupled plasma device, a radio frequency power supply loads radio frequency energy onto a radio frequency coil, and then dissociates process gas in a plasma generation chamber into plasma through an alternating electromagnetic field formed by the radio frequency coil. In this process, the coupling of radio frequency energy into the plasma generation chamber is mainly inductive coupling and supplemented by capacitive coupling. Due to the existence of capacitive coupling, after the plasma is formed, the electric field formed by the radio frequency coil will be coupled into the plasma generation chamber, and then the potential difference between the radio frequency coil and the plasma will be relatively large. The relatively large potential difference will accelerate the plasma in the sheath layer in the plasma generation chamber to bombard the dielectric window of the plasma generation chamber, and then shorten the service life of the plasma generation chamber. In order to reduce the potential difference, it is necessary that the electric field coupled by the radio frequency coil into the plasma generation chamber is as small as possible.

[0003] However, in the process of forming plasma in the plasma generation chamber, a relatively large electric field needs to be coupled by the radio frequency coil into the plasma generation chamber to achieve ignition. If the ignition is not successful, the plasma cannot be formed. However, if the ignition needs to be successful, the voltage of the radio frequency coil is relatively large, which will lead to a relatively large potential difference with the plasma, and the plasma is driven by the relatively large electric field to bombard the dielectric window. Thus, in the related art, solving the problem of difficult ignition and reducing the bombardment of the plasma on the plasma generation chamber has become a relatively difficult-to-reconcile contradiction, and how to overcome this contradiction is an important problem that those skilled in the relevant art urgently need to solve. Summary of the Invention

[0004] The present invention discloses a process chamber, an upper electrode device thereof, and a semiconductor process equipment to solve the problem that the related art cannot take into account both solving the problem of difficult ignition and the bombardment of the plasma on the dielectric window.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention discloses an upper electrode device for a process chamber. The disclosed upper electrode device includes a radio frequency coil and a tunable capacitor. The radio frequency coil is used to wind outside a shielding cylinder of the process chamber, and the shielding cylinder is used to sleeve outside a plasma generation chamber of the process chamber;

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

[0008] In a second aspect, an embodiment of the present invention discloses a process chamber. The disclosed process chamber includes a plasma generation chamber, a process reaction chamber, a shielding cylinder, and the upper electrode device described above. The process reaction chamber is in communication with the plasma generation chamber.

[0009] In a third aspect, an embodiment of the present invention discloses a semiconductor process equipment. The disclosed semiconductor process equipment 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, according to the computer program, performs the following steps:

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

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

[0012] In the case of successful ignition, adjust the adjustable capacitor to a second preset capacitance value, and the second preset capacitance value is greater than the first preset capacitance value.

[0013] The technical solution adopted by the present invention can achieve the following technical effects:

[0014] For the process chamber disclosed in the embodiment of the present invention, by improving the structure of the upper electrode device, an adjustable capacitor with an adjustable capacitance value is added and connected in series with the RF coil. Thus, the adjustable capacitor is adjusted to different capacitance values in the ignition stage and the process stage respectively, so that the voltage of the RF coil can be adjusted by adjusting the capacitance value of the adjustable capacitor. Therefore, in the ignition stage, the voltage of the RF coil can be made larger, and then the electric field coupled into the plasma generation chamber can be made larger, so that ignition is more likely to succeed. At the same time, in the process stage, the voltage of the RF coil can be adjusted by adjusting the capacitance value of the adjustable capacitor, so that the voltage of the RF coil is smaller, and thus the electric field coupled into the plasma generation chamber can be made smaller, and finally the bombardment of the plasma on the dielectric window of the plasma generation chamber can be alleviated.

[0015] It can be seen that by adding an adjustable capacitor to the upper electrode device disclosed in the embodiment of the present invention and changing the capacitance value of the adjustable capacitor in the ignition stage and the process stage, the difficult-to-reconcile contradiction of difficult ignition and reducing the bombardment of the plasma on the dielectric window can be solved. At the same time, there is no need to design the RF coil into a lifting structure. The RF coil can be completely fixedly wound outside the shielding cylinder, thus avoiding the problem of relatively easy abnormal discharge in the RF coil lifting scheme, and further avoiding the problem of relatively easy damage of the corresponding components caused by abnormal discharge. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 2 is Figure 1 a cross-sectional view of, Figure 1 and Figure 2 both do not show the process reaction chamber of the process chamber;

[0018] Figure 3 is Figure 1 a partial structural schematic diagram in;

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

[0020] Figure 5 and Figure 6 are respectively structural schematic diagrams of the radio frequency coil and the plasma generation chamber related to the present invention;

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

[0022] Figure 8 is Figure 1 a schematic diagram showing the influence of the adjustable capacitor on the potential of the radio frequency coil in the upper electrode device shown;

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

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

[0025] Figure 11 is Figure 10 a partial structural schematic diagram in;

[0026] Figure 12 is Figure 11 a partial structural schematic diagram in;

[0027] Figure 13 is Figure 12 a partial structural schematic diagram in;

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

[0029] Figure 15 and Figure 16 are respectively Figure 1 and Figure 10 the potential distribution diagrams of the radio frequency coil in the upper electrode device during the ignition stage shown;

[0030] Figure 17 andFigure 18 respectively are Figure 1 and Figure 10 the potential distribution diagrams of the radio frequency coil in the process stage of the upper electrode device shown;

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

[0032] Figure 20 is the execution step flowchart of the processor of the semiconductor process equipment disclosed in the embodiment of the present invention.

[0033] Among them, Figure 8 , Figure 9 and Figure 19 the coil in refers to the radio frequency coil 11, Figure 7 , Figure 8 , Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 the source end in refers to the first end of the radio frequency coil 11, and the end refers to the second end of the radio frequency coil 11, Figure 9 and Figure 19 the power in refers to the radio frequency power.

[0034] Explanation of reference numerals:

[0035] 10 - upper electrode device, 11 - radio frequency coil, 12 - adjustable capacitor, 13 - driving mechanism, 121 - first sub - adjustable capacitor, 122 - second sub - adjustable capacitor,

[0036] 20 - plasma generation chamber, 30 - radio frequency power supply, 40 - matcher, 50 - process gas input pipe, 60 - gas spray head, 70 - shielding cylinder, 71 - slit, 72 - flared window, 80 - shielding box. Specific embodiments

[0037] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0038] The following will detail the technical solutions disclosed in each embodiment of the present invention with reference to the drawings.

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

[0040] The upper electrode device 10 includes a radio frequency coil 11. The first end of the radio frequency coil 11 may be electrically connected to the radio frequency power supply 30 through the matcher 40, and the matcher 40 will automatically perform impedance matching adjustment. Further optionally, the matcher 40 may be electrically connected to the first end of the radio frequency coil 11 through an electrical connection bar to facilitate the electrical connection with the radio frequency coil 11. Of course, the first end of the radio frequency coil 11 may be directly electrically connected to the matcher 40.

[0041] The second end of the radio frequency coil 11 is used for electrical connection to the ground. Specifically, the radio frequency coil 11 may be used for direct electrical connection to the ground or may be indirectly electrically connected to the ground through other grounding components, which is not limited in the embodiments of the present invention.

[0042] The first end of the process gas input pipe 50 may be communicated with a process gas source, and the second end of the process gas input pipe 50 may be communicated with the gas showerhead 60 installed on the plasma generation chamber 20 and communicated with the plasma generation chamber 20 through the gas showerhead 60. The process gas may flow out from the process gas source, then enter the plasma generation 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 generation chamber 20. The gas showerhead 60 may adopt a structure capable of distributing the process gas so that the process gas is transported to the plasma generation chamber 20 as evenly as possible. The plasma generation chamber 20 may be a dielectric tube made of materials such as quartz and ceramics. The dielectric tube may be cylindrical or may have other shapes, which is not limited in the embodiments of the present invention.

[0043] The shielding cylinder 70 plays a shielding role. The shielding cylinder 70 may be a Faraday cage. The shielding cylinder 70 is sleeved outside the plasma generation chamber 20 to play a certain shielding role. The radio frequency coil 11 is wound outside the shielding cylinder 70. After the radio frequency coil 11 is powered on, it will generate a magnetic field and an electric field. The shielding cylinder 70 hardly loses the magnetic field coupled to the plasma generation chamber 20, but will shield the electric field generated by the radio frequency coil 11, thereby reducing the electric field coupled by the radio frequency coil 11 into the plasma generation chamber 20. That is to say, the radio frequency coil 11 is not only wound outside the shielding cylinder 70, but also wound outside the plasma generation chamber 20.

[0044] During the specific working process, the RF power supply 30 transmits the RF power (which can be understood as RF energy) to the RF coil 11 through the matcher 40 and finally leads 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 into the (RF) 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 dissociating the process gas to form a plasma and completing 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 communicated with the plasma generation chamber 20, and the plasma with a density meeting the process requirements 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 communicated with the plasma generation chamber 20.

[0045] As can be seen from the above description, the process gas needs to form a plasma first and then participate in the process reaction. Correspondingly, the process chamber disclosed in the embodiments of the present invention needs to go through 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 the ignition stage to be able to ignite successfully.

[0046] The shielding cylinder 70 can shield a part of the electric field of the RF coil 11. The shielding cylinder 70 is grounded, so the potential of the shielding cylinder 70 is relatively low. As a result, the potential difference between the formed plasma and the shielding cylinder 70 is relatively small, and further the potential difference between the plasma and the dielectric window of the plasma generation chamber 20 (the dielectric window is located between the shielding cylinder 70 and the plasma) is relatively small, thereby being able to relieve the bombardment of the dielectric window by the plasma under the action of the electric field and achieving the purpose of extending the service life of the plasma generation chamber 20. Optionally, the shielding cylinder 70 can be installed inside the shielding box 80 described later and can be electrically connected to the shielding box 80 and finally grounded through the shielding box 80.

[0047] The process gas needs to be ignited before forming plasma, that is, the process chamber described above will go through an ignition stage when working. The inventors of the present invention found in the process of realizing the present invention that although the shielding tube 70 can play a shielding function to prevent plasma from bombarding the plasma generating chamber 20, the RF coil 11 needs to increase the capacitive coupling during the ignition stage, so that more electric fields are coupled into the plasma generating chamber 20 to realize the ignition of the process gas (i.e. ignition), and this requirement is difficult to achieve precisely because of the shielding function of the shielding tube 70. In other words, the setting of the shielding tube 70 can indeed alleviate the bombardment of the medium window by the plasma, but it will cause ignition difficulties during the ignition stage, and ultimately make it difficult to succeed in ignition. If you want to solve the problem of ignition difficulty, you need to try not to set the shielding tube 70. It can be seen that solving the ignition difficulty and solving the bombardment of the plasma generating chamber 20 by the plasma have become contradictions that are difficult to reconcile.

[0048] Based on this, the inventors improved the process chamber so that the RF coil 11 can be raised and lowered relative to the plasma generating chamber 20. This design uses 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 making it easier to form a larger voltage on the RF coil 11 for ignition, thereby making it easier to succeed in ignition. When the ignition is successful, the height of the RF coil 11 is lowered again, so that the RF coil 11 is closer to the process reaction chamber, thereby ensuring the efficiency of the process reaction.

[0049] However, the inventor further found that for this solution, the current in the radio frequency coil 11 is relatively large, and the electrical connection strip connecting the radio frequency coil 11 to the matcher 40 or the radio frequency power supply 30 is generally wide and hard. The radio frequency coil 11 carries a very high voltage. If there is a loose connection between the electrical connection strip and the radio frequency coil 11, it is relatively easy to cause abnormal discharge at the contact point, which will further cause damage to the components (radio frequency coil 11, electrical connection strip) and process failure. In order to avoid abnormal discharge, the electrical connection strip and the radio frequency coil 11 need to be connected in a good hard contact manner, which determines that the radio frequency coil 11 needs to be fixedly installed. Obviously, this determines that it is difficult to design the radio frequency coil 11 into a movable structure that can be lifted and lowered. Then, the voltage of the radio frequency coil 11 is usually several thousand volts or even tens of thousands of volts, and the shielding cylinder 70 is grounded. In order to ensure the coupling efficiency, the distance between the radio frequency coil 11 and the shielding cylinder 70 is not too large, only a few millimeters to more than ten millimeters. Therefore, special attention needs to be paid to the withstand voltage design between the radio frequency coil 11 and the shielding cylinder 70. And the radio frequency coil 11 is prone to abnormal discharge with the shielding cylinder 70 during the lifting process. It can be seen that the lifting design of the radio frequency coil 11 has relatively high requirements for the withstand voltage design. If there is a slight carelessness, the lifting radio frequency coil 11 is extremely easy to have creeping arc discharge with the shielding cylinder 70, which will further cause damage to the components (radio frequency coil 11, shielding cylinder 70). Then, the lifting of the radio frequency coil 11 takes a relatively long time, and it will also cause a change in the load impedance of the matcher 40. The matcher 40 needs to re-match the impedance, which ultimately leads to a relatively long time consumption in the entire ignition stage and ultimately results in a low production capacity of the process chamber.

[0050] Based on the various problems presented above, the inventor of the present invention further improves the structure of the process chamber, so that the upper electrode device 10 involved in the embodiments of the present invention may further include a tunable capacitor 12.

[0051] The adjustable capacitor 12 is a capacitor device whose capacitance value can be adjusted. In the embodiments of the present 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 stage and the reaction stage 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 matcher 40 performs impedance matching adjustment, the voltage of the radio frequency coil 11 can be adjusted to a higher voltage, so that even if a part of the electric field generated by the radio frequency coil 11 is shielded by the shielding cylinder 70, a relatively large electric field can still be coupled into the plasma generation chamber 20, making it easier to achieve successful ignition. After the ignition stage is completed and the process stage is entered, in order to prevent too much electric field generated by the radio frequency coil 11 from being coupled into the plasma generation chamber 20, the capacitance value of the adjustable capacitor 12 is further adjusted so that after the matcher 40 performs impedance matching adjustment, the voltage of the radio frequency coil 11 can be adjusted to a lower voltage, so that after a part of the electric field generated by the radio frequency coil 11 is shielded by the shielding cylinder 70, the electric field that can be coupled into the plasma generation chamber 20 is already small, and it will not cause the plasma to bombard the plasma generation chamber 20 under the drive of a large electric field.

[0052] Specifically, during the ignition stage, the capacitance value of the adjustable capacitor 12 can be adjusted to a first capacitance value, and the matcher 40 performs impedance matching adjustment according to the first capacitance value to adjust the voltage of the radio frequency coil 11 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 successful ignition, and the embodiments of the present invention do not limit the specific value of the ignition voltage. During the reaction stage, the capacitance value of the adjustable capacitor 12 is adjusted to a second capacitance value, and the matcher 40 performs impedance matching adjustment according to the second capacitance value to adjust the voltage of the radio frequency coil 11 to a second voltage, and the second voltage is less than the ignition voltage, so as to avoid coupling a relatively large electric field into the plasma generation chamber 20. Among them, the first capacitance value is less than the second capacitance value.

[0053] In the process chamber disclosed in the embodiments of the present 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 RF coil 11. As a result, the adjustable capacitor 12 is adjusted to different capacitance values during the ignition stage and the process stage respectively, so that the voltage of the RF coil 11 can be adjusted by adjusting the capacitance value of the adjustable capacitor 12. During the ignition stage, the voltage of the RF coil 11 is relatively large, and thus the electric field coupled into the plasma generation chamber 20 is relatively large (i.e., the capacitive coupling is increased to make the electric field coupled into the plasma generation chamber 20 stronger), making it easier for ignition to succeed. At the same time, during the process stage, the voltage of the RF coil 11 can be adjusted by adjusting the capacitance value of the adjustable capacitor 12, making the voltage of the RF coil 11 relatively small, so that the electric field coupled into the plasma generation chamber 20 is relatively small (i.e., the capacitive coupling is reduced to make the electric field inside the plasma generation chamber 20 weaker), ultimately alleviating the bombardment of the dielectric window of the plasma generation chamber 20 by the plasma.

[0054] It can be seen that by adding the adjustable capacitor 12 to the upper electrode device 10 disclosed in the embodiments of the present invention and changing the capacitance value of the adjustable capacitor 12 during the ignition stage and the process stage, the difficult-to-reconcile contradiction of difficult ignition and reducing the bombardment of the dielectric window by the plasma can be solved. At the same time, there is no need to design the RF coil 11 into a lifting structure. The RF coil 11 can be completely fixed and wound outside the shielding cylinder 70, thus avoiding the problem that the corresponding components are easily damaged due to abnormal discharge that is likely to occur in the RF coil 11 lifting scheme.

[0055] As described above, the adjustable capacitor 12 is connected in series with the RF coil 11. Specifically, there are various ways to connect the adjustable capacitor 12 in series with the RF coil 11. In an optional solution, the first end of the RF coil 11 is used to be electrically connected 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, thus realizing the 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 conveniently ensure the integrity of the RF coil 11 (i.e., the RF coil 11 can be formed by winding a single wire), and at the same time, as much as possible, avoid making major changes to the RF coil 11. That is to say, on the basis of the RF coil 11 in the process chamber of the related art, the adjustable capacitor 12 can be added between its second end and the ground, with minor changes and easy to implement.

[0056] Furthermore, the adjustable capacitor 12 can be one or at least two. The embodiments of the present invention do not limit the number of adjustable capacitors 12. Of course, when there are at least two adjustable capacitors 12 connected in series between the second end of the RF coil 11 and the ground, these adjustable capacitors 12 can be connected in series or in parallel between the second end of the RF coil 11 and the ground.

[0057] Specifically, there is one adjustable capacitor 12. The RF coil 11 can be formed by winding a single wire. 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 during the ignition stage can be greater than Z coil , for example, 1.2Z coil , and the impedance value of the adjustable capacitor 12 during the reaction stage can be greater than 0 and less than Z coil , optionally, the impedance value of the adjustable capacitor 12 during 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 during 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 easier to balance and solve the problems of difficult ignition and plasma bombarding the plasma generation chamber 20. The following will be described in detail in combination with Figure 7 and Figure 8 .

[0058] In Figure 7 and Figure 13 , the matcher (i.e., Match in Figure 7 , Figure 9 , Figure 14 and Figure 19 ) 40 can adopt a mature and general L-type full-automatic matcher on the current market. The sensor inside the matcher 40 reads the RF voltage and RF current, calculates the impedance value, and through the control program, the capacitance value of the adjustable capacitor 12 is adjusted, so that the impedance at the rear end 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 (the rear-end load includes the RF coil 11 and the adjustable capacitor 12) of the upper electrode device 10. It should be noted that the matcher 40 in this article serves the purpose of impedance matching, and its structure and working principle are both known and mature technologies, which will not be elaborated here.

[0059] Please first refer to Figure 7 , the inductance of the RF coil 11 is L coil , the real part impedance of the load such as the RF coil 11 is R, and the adjustable capacitor 12 connected to the second end of the RF coil 11 is C 3 , the first tuning capacitor and the second tuning capacitor of the matcher 40 are C 1 and C 2, the first tuning capacitor and the second tuning capacitor are used to adjust the impedance of the backend load to the impedance (e.g., 50 Ω) output by the RF power supply 30 to ensure maximum power transfer to the backend load. Assume the current flowing into the RF coil 11 is I, and the voltage at the source end (i.e., the first end) of the RF coil 11 is V. There is a voltage-current sensor (Sensor) at the output end of the matcher 40, which can be used to monitor the potential at the source end of the RF coil 11. The potential at the source end of the RF coil 11 is:

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

[0061] where the impedance of the RF coil 11 is Z coil = jωL coil , the impedance of the adjustable capacitor 12 (i.e., C 3 ) is The angular frequency ω = 2πf, where f is the frequency of the output signal of the RF power supply 30. After the matcher 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 end of the RF coil 11 is:

[0062]

[0063] In an inductively coupled plasma source, if the structure of the RF coil 11 remains unchanged, the density of the plasma is positively correlated with the current of the RF coil 11. The greater the current of the RF coil 11, the higher the plasma density. Adjust the capacitance value of the adjustable capacitor 12 (i.e., C 3 ) at the second end of the RF coil 11. After the matcher 40 adjusts C 1 , C 2 and rematches, the current value flowing through the RF coil 11 remains almost unchanged, which does not affect the density of the excited plasma, but can change the voltage distribution on the RF coil 11. By reducing the average potential and the maximum potential on the RF coil 11, capacitive coupling can be reduced, the electric field strength in the sheath layer can be reduced, and the plasma accelerated by the electric field to bombard the dielectric window will be weakened, thereby being able to relieve the plasma bombardment of the dielectric window of the plasma generation chamber 20.

[0064] If the structure of the RF coil 11 remains unchanged, then the impedance Z coil of the RF coil 11 remains unchanged; change the adjustable capacitor (i.e., C 3)The magnitude of 12 does not affect the current flowing through the radio frequency coil 11. It should be noted that for the impedance Z = R + jX, R is the real part impedance, and the power it consumes is the active power. X is the imaginary part impedance, and the power it consumes is the reactive power. The power output by the radio frequency power supply 30 is all active power. The process chamber (such as an etching machine) generally uses a radio frequency power supply 30 with a constant power. The radio frequency power (i.e., Power) of the radio frequency power supply 30 is of a certain magnitude. According to Power = I 2 R, changing the adjustable capacitor (i.e., C 3 )12 only changes the imaginary part impedance X and does not affect the magnitude of the real part impedance R. Therefore, it does not affect the magnitude of the current I. From this, it can be seen that the potential difference ΔV across the two ends of the radio frequency coil 11 is basically the same. Here, it is uniformly denoted as:

[0065] ΔV = I·jωL coil = 2V 0 (3)

[0066] At the same radio frequency power, the potential difference across the two ends of the radio frequency coil 11 is 2V 0 . The influence of different C 3 capacitance values on the potential distribution on the radio frequency coil 11 is as shown in Figure 8 , and the corresponding values are as shown in Figure 8 and Table 1. It can be seen that when Z C3 > Z coil , both the average potential and the maximum potential on the radio frequency coil 11 are relatively large. At this time, the electric field coupled into the plasma generation chamber 20 is the strongest, which is most conducive to ignition. When Z C3 = 0.5Z coil , both the average potential and the maximum potential on the radio frequency coil 11 are the smallest. At this time, the electric field coupled into the plasma generation chamber 20 is the weakest, and the plasma in the sheath bombards the plasma generation chamber 20 the weakest.

[0067] Table 1

[0068]

[0069] According to this characteristic, in case ⑥ in Table 1, the average potential of the radio frequency coil 11 is the highest and the electric field is the strongest, which is conducive to ignition. The capacitance value setting of the adjustable capacitor 12 in case ⑥ can be used for gas ignition to dissociate the process gas so that the process gas forms a plasma. In case ③ in Table 1, the average potential of the radio frequency coil 11 is the lowest and the electric field is the weakest. The capacitance value setting of the adjustable capacitor 12 in case ③ is more suitable for the process reaction process (i.e., more suitable for the reaction stage).

[0070] For the convenience of understanding the ignition process, please refer to Figure 9 . Before applying the radio frequency power, adjust C 3 to satisfy Z C3= 1.2Z coil > Z coil Of course, it only needs to satisfy Z C3 > Z coil That's all. Note: Here, an example of > 1 is given. Actually, it can be preset as 1.1Z coil 、1.3Z coil etc., but the adjustment of the capacitance value of C 3 cannot exceed the lower limit of the capacitance range of C 3 . Under this condition, the overall potential of the radio frequency coil 11 is relatively high. After ventilating and controlling the pressure of the chamber (i.e., the plasma generation chamber 20), radio frequency power is loaded, and C 1 、C 2 of the Match (i.e., the matcher 40) is adjusted for impedance matching so that the radio frequency power is loaded on loads such as the radio frequency coil 11. At this time, the electric field formed by the radio frequency coil 11 is stronger, which is beneficial for ignition.

[0071] The method for judging whether ignition is successful: A voltage-current sensor (i.e., Sensor in the figure) is installed at the output end of the Match. In the early stage, the voltage V 1 of the static impedance at the moment of ignition and the voltage V 2 after breakdown are collected through manual tests. Since V 2 is significantly less than V 1 , a voltage threshold V 0 = 0.5V 1 + 0.5V 2 can be specified. At the moment of ignition, the Sensor reads the voltage V. If V drops from being greater than V 0 to being less than V 0 , it is considered that ignition is successful. If ignition fails, the value of C 3 is continued to be reduced (for example, the capacitance value obtained by multiplying the current value of C 3 by 0.9 is used as the adjusted capacitance value of C 3 ), and matching is carried out again until ignition is successful.

[0072] After ignition is successful, C 3 is readjusted so that the impedance value of C 3 satisfies Z C3 = 0.5Z coil . In this case, the overall potential of the radio frequency coil 11 is the lowest. Then, the Match adjusts C 1 、C 2 for impedance matching so that the radio frequency power is fully loaded on loads such as the radio frequency coil 11 again, and then the process stage is entered.

[0073] As described above, the first end of the radio frequency coil 11 is used for electrically connecting to the radio frequency power supply 30 of the process chamber, and the second end of the radio frequency coil 11 is used for grounding. In another alternative solution, the adjustable capacitor 12 may include at least one first sub-adjustable capacitor 121, the radio frequency coil 11 may include at least two coil segments connected in series, and each first sub-adjustable capacitor 121 may be connected in series between two adjacent coil segments. In this case, the radio frequency coil 11 is not a single piece of wire, but multiple separate pieces of wire (at least two). In this case, during the process of adjusting 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 the present 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. As Figures 9 to 12 shown, the first sub-adjustable capacitor 121 may be two, the radio frequency coil 11 may include three coil segments, and the first sub-adjustable capacitor 121 may be two and are respectively connected between two adjacent coil segments.

[0076] Please refer to Figures 9 to 12 again. In a further technical solution, the adjustable capacitor 12 may further include a second sub-adjustable capacitor 122, and the second sub-adjustable capacitor 122 is used for connecting between the second end of the radio frequency coil 11 and the ground. During the process of adjusting 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 purpose of the present invention.

[0077] In the case where the adjustable capacitor 12 includes the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122, during the ignition stage, the impedance values of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 can both be greater than Z coil , for example 1.2Z coil ; during the reaction stage, the impedance values of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122 can both be greater than 0 and less than Z coil .

[0078] In other embodiments, during the reaction stage, the impedance value of the first sub-adjustable capacitor 121 can be Z coil / n, and the impedance value of the second sub-adjustable capacitor 122 can be Z coil / 2n. This optional solution makes it easier to balance the problems of difficult ignition and plasma bombardment of the plasma generation chamber 20. Here, 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. Correspondingly, in the reaction stage, the impedance value of the first sub-adjustable capacitor 121 is Z coil / 3, and the impedance value of the second sub-adjustable capacitor 122 is Z coil / 6. The following will be described in conjunction with Figures 10 to 18 for illustration.

[0079] As Figure 12 and Figure 13 shown, the RF coil 11 is divided into three coil segments, and the total inductance of the RF coil 11 is L coil , which can be evenly divided into 3 parts, and the inductance of each segment is L coil / 3. The real part 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 C 3 , and the two first sub-adjustable capacitors 121 connected in series to the RF coil 11 respectively correspond to C 4 , C 5 in the schematic diagram. The first tuning capacitor and the second tuning capacitor in the fully automatic matcher (Match) 40 are C 1 and C 2 respectively, which are used to adjust the impedance of the rear-end load to the impedance output by the RF power supply 30 (such as 50 Ω) to ensure maximum power transmission to the rear-end load. Assume that the current flowing into the RF coil 11 is I and the source-end voltage of the RF coil 11 is V. There is a voltage-current sensor (such as the Sensor in Figure 14 ) at the output end of the Match, 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:

[0080] V = I(R + Z coil + Z 3 + Z 4 + Z 5 ) (4)

[0081] Among them, the impedance Z coil of the RF coil 11 = jωL coil , the impedance 3 of the second sub-adjustable capacitor (i.e., C ) 122, the impedance 4 of the capacitor (i.e., one first sub-adjustable capacitor 121) C connected in series with the coil segment, and the impedance 5 of the capacitor (i.e., the other first sub-adjustable capacitor 121) C 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 end of the RF coil 11 is:

[0082]

[0083] In an inductively coupled plasma source, if the structure of the RF coil 11 remains unchanged, the density of the plasma is positively correlated with the current of the RF coil 11. The greater the current of the RF coil 11, the higher the plasma density. By adjusting the capacitance values of the second sub-adjustable capacitor (i.e., C 3 ) 122 at the rear end of the RF coil 11 and the two first sub-adjustable capacitors (i.e., C 4 , C 5 ) 121, after the Match adjusts C 1 , C 2 , after rematching, the current value flowing through the RF coil 11 remains almost unchanged, without affecting the density of the excited plasma, but the voltage distribution on the RF coil 11 can be changed. By reducing the average potential and the maximum potential on the RF coil 11, capacitive coupling can be reduced, and the electric field in the sheath region can be reduced, so that the plasma accelerated by the electric field bombarding the plasma generation chamber 20 will be weakened.

[0084] If the structure of the RF coil 11 remains unchanged, the impedance Z coil of the RF coil 11 remains unchanged; by changing the magnitudes of C 3 and C 4 , C 5 , without affecting the current flowing through the RF coil 11, the potential difference ΔV between the two ends of the RF coil 11 is basically the same, which is uniformly denoted here as:

[0085] ΔV = I·jωL coil = 2V 0 (6)

[0086] At the same RF power, the potential difference between the two ends of the RF coil 11 is 2V 0 . In the structure shown in Figure 15 , the RF coil 11 is evenly divided into 3 coil segments, and the potential drop of each coil segment is 2V 0 / 3 ≈ 0.67V 0 . When the structure where 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 as shown in Figure 15 , and the impedance value Z C3 corresponding to the adjustable capacitor 12 of the RF coil 11 is 1.2Z coil . Then the maximum potential amplitude on the RF coil 11 is 2.4V 0 .

[0087] When the structure of 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 radio frequency coil 11 is as Figure 16 shown. The impedance value Z of the second sub-adjustable capacitor 122 connected to the radio frequency coil 11 C3 = 1.2Z coil , and the impedance values of the two first sub-adjustable capacitors 121 are Z C4 and Z C5 respectively. Among them, Z C4 = Z C5 = 1.2Z coil , then the maximum potential amplitude on the radio frequency coil 11 is 5.86V 0 . Thus, compared with Figure 15 the structure of the upper electrode device 10 shown, Figure 16 the structure shown can enable the radio frequency coil 11 to obtain a higher potential at the moment of ignition, the electric field coupled to the plasma generation chamber 20 is stronger, and it is more conducive to ignition to complete the glow start (i.e., complete ignition).

[0088] When the adjustable capacitor 12 is only distributed between the second end of the radio frequency coil 11 and the ground, during the process stage, the potential distribution of the radio frequency coil 11 is as Figure 17 shown. The impedance value Z of the adjustable capacitor 12 of the radio frequency coil 11 C3 = 0.5Z coil , then the maximum potential amplitude on the radio frequency coil 11 is V 0 . When the structure of the adjustable capacitor 12 includes two first sub-adjustable capacitors 121 and a second sub-adjustable capacitor 122 and is in the process stage, the potential distribution of the radio frequency coil 11 is as Figure 18 shown. The impedance value Z of the second sub-adjustable capacitor 122 of the radio frequency coil 11 C3 = Z coil / 6, and the impedance values of the two first sub-adjustable capacitors 121 are Z C4 and Z C5 respectively. Among them, Z C4 = Z C5 = Z coil / 3, then the maximum potential amplitude on the radio frequency coil 11 is V 0 / 3. Compared with the structure shown in Figure 17 , the structure shown in Figure 18 can enable the radio frequency coil 11 to obtain a lower potential during the process stage, and then make the electric field coupled by the radio frequency coil 11 to the plasma generation chamber 20 weaker, which is more conducive to keeping the plasma generation chamber 20 with lower damage during the process.

[0089] According to this feature, an ignition process can be designed as shown in Figure 19As shown. Before loading the power, adjust C 3 , C 4 , C 5 to satisfy Z C3 = Z C4 = Z C5 = 1.2Z coil > Z coil . Under this condition, the overall potential of the radio frequency coil 11 is relatively high. After ventilating and controlling the pressure in the chamber (i.e., the plasma generation chamber 20), load the radio frequency power and adjust the C 1 , C 2 of the Match for impedance matching so that the radio frequency power is loaded on loads such as the radio frequency coil 11. At this time, the electric field coupled by the radio frequency coil 11 into the plasma generation chamber 20 is relatively strong, which is beneficial for ignition.

[0090] The method for judging whether ignition is successful: A voltage-current sensor is installed at the output end of the Match (i.e., Sensor in the figure). Manually test in the early stage to collect the voltage V 1 at the static impedance at the moment of ignition and the voltage V 2 after breakdown (i.e., after successful ignition). Since V 2 is significantly less than V 1 , a voltage threshold V 0 = 0.5V 1 + 0.5V 2 can be specified. At the moment of ignition, the Sensor reads the voltage V. If V drops from being greater than V 0 to being less than V 0 , it is considered that ignition is successful. If ignition fails, continue to reduce the values of C 3 , C 4 , C 5 (for example, use the capacitance values obtained by multiplying the current values of C 3 , C 4 and C 5 by 0.9 as the adjusted capacitance values of C 3 , C 4 and C 5 ), and re-match until ignition is successful.

[0091] After successful ignition, readjust C 3 , C 4 , C 5 so that the impedance value Z 3 of C C3 = Z coil / 6, and the impedance values Z 4 corresponding to the capacitance values of C 5 and C C4 , Z C5 satisfy Z C4 = ZC5 = Z coil / 3. In this case, the overall potential of the RF coil 11 is the lowest. Then, the Match adjusts C 1 and C 2 for impedance matching, so that all the RF power is reloaded on loads such as the RF coil 11, and then ignition is completed and the process stage is entered.

[0092] In the embodiment of the present invention, there are various 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 an optional solution, the upper electrode device 10 disclosed in the embodiment of the present 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 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, so as to adjust the rotation or movement of the first capacitor plate or the second capacitor plate, so as to achieve the purpose of adjusting the capacitance value. The method of using the driving mechanism 13 to adjust the capacitance value of the adjustable capacitor 13 can quickly achieve the purpose of adjusting the voltage of the RF coil 11. Compared with the lifting adjustment of the RF coil 11, the method of using the driving mechanism 13 in cooperation with the adjustable capacitor 12 can achieve successful ignition faster, which is beneficial to improving production capacity.

[0093] Of course, in the case where the adjustable capacitor 12 includes a first sub-adjustable capacitor 121, the process chamber may configure 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 to move. In the case where the adjustable capacitor 12 includes a second sub-adjustable capacitor 122, the process chamber may also configure 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 to move.

[0094] As described above, the structure of the shielding cylinder 70 can be various, and the shielding cylinder 70 is a hollow cylindrical member. Specifically, the shielding cylinder 70 can be provided with a plurality of slits 71 that are spaced apart in the circumferential direction of the shielding cylinder 70, and the plurality of slits 71 can be evenly distributed in the circumferential direction of the shielding cylinder 70, which is beneficial to more evenly couple a relatively uniform magnetic field through the shielding cylinder 70 into the plasma generation chamber 20, so as to more favorably enable the plasma generated in the plasma generation chamber 20 to meet the process requirements. The number of slits 71 can be 6, or 4 or 8. The specific number of slits 71 is not limited in the embodiments of the present invention.

[0095] The widths of all parts of the slit 71 can be equal. In other embodiments, the widths 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 outside the middle part of the slit 71. As described 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 made larger during the ignition stage, and then the electric field coupled by the RF coil 11 into the plasma generation chamber 20 can be made larger. Finally, even if the width of the slit 71 is small, it can ensure that ignition is relatively easy. In this alternative embodiment, winding the RF coil 11 outside the middle part with a smaller width of the slit 71 can enable 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 generation chamber 20 during the process stage, while also ensuring that the magnetic field is coupled into the plasma generation chamber 20 from the shielding cylinder 70 without damage.

[0096] Of course, since the RF coil 11 is wound in the middle part of the slit 71, considering the magnetic field distribution of the RF coil 11, the widths at both ends of the slit 71 are larger, making it easier for the magnetic field generated by the RF coil 11 to be coupled into the plasma generation chamber 20.

[0097] In a further technical solution, the shielding cylinder 70 can also be provided with a plurality of flared windows 72, and the plurality of flared windows 72 are in one-to-one correspondence and communication with the ends of the plurality of slits 71. The size of the plurality of flared windows 72 in the width direction of the slit 71 is greater than the width of the corresponding slit 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 be blocked (for example, easily blocked 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 into the plasma generation chamber 20 through the flared windows 72, thereby ensuring the inductive coupling effect.

[0098] As described above, the shielding cylinder 70 is used for grounding, so as to ensure that the potential of the shielding cylinder 70 is relatively low, reduce the potential difference between the shielding cylinder 70 and the plasma, and thus avoid the plasma bombarding the plasma generation chamber 20. In a more preferred solution, the shielding cylinder 70 may include a plurality of grounding portions. The plurality of grounding portions are located at the end of the shielding cylinder 70 and may be evenly distributed along the circumferential direction of the shielding cylinder 70. Designing a plurality of grounding portions evenly distributed in the circumferential direction can achieve multi-point symmetric grounding of the shielding cylinder 70, and then can achieve grounding more evenly, and finally can ensure the symmetry of the return path to ensure the uniformity of the electromagnetic field coupled into the plasma generation chamber 20. The plurality of grounding portions may be located at the lower bottom end of the shielding cylinder 70 or at the higher top end of the shielding cylinder 70, and the embodiments of the present invention do not limit this.

[0099] Of course, as described above, when the adjustable capacitor 12 includes the first sub-adjustable capacitor 121, or when the adjustable capacitor 12 includes the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122, since the shielding cylinder 70 is provided with a plurality of gaps 71 spaced apart along the circumferential direction 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, and thus it is easy to cause angular asymmetry of the electromagnetic field. Based on this, in an alternative solution, the first sub-adjustable capacitor 121 may be misaligned with the gaps 71. Of course, when the adjustable capacitor 12 includes the second sub-adjustable capacitor 122, the second sub-adjustable capacitor 122 may also be misaligned with the gaps 71, as Figure 10 and Figure 11 shown. This misaligned distribution method hardly causes eccentricity of the process result due to the discontinuity of the radio frequency coil 11.

[0100] The process chamber disclosed in the embodiments of the present invention may further include a shielding box 80, and the shielding box 80 is used for grounding. The second end of the radio frequency coil 11 is electrically connected to the shielding box 80 to achieve grounding. The plasma generation chamber 20, the shielding cylinder 70, the radio frequency coil 11, and the adjustable capacitor 12 may be disposed within the shielding box 80, so as to be protected by the shielding box 80, and at the same time, it can also avoid the interference of the magnetic field 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 to achieve grounding. In the embodiments of the present invention, both the shielding cylinder 70 and the shielding box 80 may be made of metal.

[0101] When the process chamber includes the driving mechanism 13, as Figure 1 and Figure 2As shown, in a more preferred solution, the driving mechanism 13 can be installed outside the shielding box 80 and connected to the adjustable capacitor 12 provided inside the shielding box 80 through a connecting shaft. This arrangement can alleviate the adverse effect that the driving mechanism 13 located inside the shielding box 80 is likely to have on the magnetic field generated by the radio frequency coil 11.

[0102] In a further technical solution, the radio frequency power supply 30 and the matcher 40 can be located outside the shielding box 80 and installed on the shielding box 80. In this case, the shielding box 80 can also provide an installation position for the radio frequency power supply 30 and the matcher 40. Of course, the radio frequency power supply 30 and the matcher 40 are located outside the shielding box 80, so as to avoid 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 embodiments of the present invention further disclose a semiconductor process equipment. The disclosed semiconductor process equipment includes a controller and the process chamber described in any one of the above embodiments. The controller includes a memory and a processor. The memory stores a computer program. As Figure 20 shown, the processor executes the following steps according to the computer program:

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

[0105] In an alternative solution, when the adjustable capacitor 12 is only connected between the second end of the radio frequency coil 11 and the ground, in this step, the capacitance value of the adjustable capacitor 12 can be adjusted to the first preset capacitance value so that the impedance value of the adjustable capacitor 12 is greater than Z coil , such as 1.2Z coil , so that the potential of the radio frequency coil 11 is relatively high after the radio frequency power is loaded.

[0106] In another alternative solution, when the adjustable capacitor 12 includes the two first sub-adjustable capacitors 121 and one second sub-adjustable capacitor 122 described above, in this step, the capacitance values of the two first sub-adjustable capacitors (i.e., C 4 and C 5 ) 121 and the second sub-adjustable capacitor (i.e., C 3 ) 122 can be respectively adjusted to the first preset capacitance value so that the impedance values of the second sub-adjustable capacitor 122 and the two first sub-adjustable capacitors 121 are both greater than Z coil , such as 1.2Z coil , so that the potential of the radio frequency coil 11 is relatively high after the radio frequency power is loaded.

[0107] S102. Load radio frequency power to the radio frequency coil 11.

[0108] Of course, before loading the radio frequency power, it is also necessary to introduce process gas into the plasma generation chamber 20 and control the air pressure in the plasma generation chamber 20. After loading the radio frequency power, the matcher 40 automatically adjusts its own C 1 (i.e., the first tuning capacitor of the matcher 40) and C 2 (i.e., the second tuning capacitor of the matcher 40) for impedance matching, so that the radio frequency power is loaded on loads such as the radio frequency coil 11.

[0109] S103. Determine whether the ignition is successful.

[0110] S104. In the case of successful ignition, adjust the adjustable capacitor 12 to a second preset capacitance value.

[0111] In an alternative solution, when the adjustable capacitor 12 is only connected between the second end of the radio frequency coil 11 and the ground, in this step, the capacitance value of the adjustable capacitor (i.e., C 3 ) 12 can be adjusted to the second preset capacitance value, so that the impedance value of the adjustable capacitor 12 is 0.5Z coil , thereby making the potential of the radio frequency coil 11 relatively low. Among them, the second preset capacitance value is greater than the first preset capacitance value.

[0112] In another alternative solution, when the adjustable capacitor 12 includes the two first sub-adjustable capacitors 121 and one second sub-adjustable capacitor 122 described above, in this step, the capacitance values of the two first sub-adjustable capacitors (i.e., C 4 and C 5 ) 121 and the second sub-adjustable capacitor (i.e., C 3 ) 122 can be adjusted respectively, so that the impedance value of the second sub-adjustable capacitor 122 is Z coil / 6, and the impedance values of the two first sub-adjustable capacitors 121 can both be Z coil / 3, thereby making the potential of the radio frequency coil 11 relatively low after loading the radio frequency power.

[0113] Of course, after S104, it is also possible to control the matcher 40 to automatically adjust its own C 1 and C 2 for impedance matching, so that the radio frequency power is loaded on loads such as the radio frequency coil 11.

[0114] It should be noted that C 3 involved in the embodiments of the present invention can be considered as the part of the adjustable capacitor 12 connected between the second end of the radio frequency coil 11 and the ground. When the adjustable capacitor 12 is a capacitor only connected between the second end of the radio frequency coil 11 and the ground, for C 3The adjustment of can be regarded as the overall adjustment of the adjustable capacitor 12. When the adjustable capacitor 12 includes a first sub-adjustable capacitor 121 and a second sub-adjustable capacitor 122, the adjustment of C 3 The adjustment of can be regarded as the adjustment of 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, the adjustment of the adjustable capacitor 12 requires the adjustment of the first sub-adjustable capacitor 121 and the second sub-adjustable capacitor 122.

[0115] Furthermore, it may further include:

[0116] S105. When the ignition is unsuccessful, reduce the capacitance value of the adjustable capacitor 12, and restart the step of judging whether the ignition is successful.

[0117] In this step, for example, the current capacitance value of the adjustable capacitor 12 can be multiplied by a preset coefficient as the adjusted capacitance value for reduction. The preset coefficient is less than 1. For example, the preset coefficient can be 0.9. As Figure 9 shown. Of course, the specific size of the preset coefficient is not limited in the embodiments of the present 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 (such as 0.9) respectively as the adjusted capacitance value for adjustment. As Figure 19 shown.

[0118] Please refer to Figure 9 , in an alternative solution, the adjustable capacitor 12 can be at least one, where:

[0119] 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, for example, 1.2Z coil ;

[0120] Between loading radio frequency power to the radio frequency coil 11 and judging whether the ignition is successful, the processor further executes: adjusting the first tuning capacitor and the second tuning capacitor of the matcher of the semiconductor process equipment for impedance matching so that the radio frequency power is at least loaded on the radio frequency coil 11;

[0121] When the ignition is successful, adjusting the adjustable capacitor 12 to a second preset capacitance value includes: increasing the capacitance value of the adjustable capacitor 12 to a 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, for example, 0.5Z coil ;

[0122] 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 matcher for impedance matching so that the radio frequency power is at least loaded on the radio frequency coil 11;

[0123] In the case where ignition is not successful, reducing the capacitance value of the adjustable capacitor 12 includes: multiplying the current capacitance value of the adjustable capacitor 12 by a preset coefficient (such as 0.9) and using it as the capacitance value of the adjustable capacitor 12 after reduction, and the preset coefficient is less than 1.

[0124] Please refer to Figure 19 , in another alternative solution, the adjustable capacitor 12 may include, for example, two first sub-adjustable capacitors 121 and one second sub-adjustable capacitor 122, and the radio frequency 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, and the second sub-adjustable capacitor 122 is used to connect between the second end of the radio frequency coil 11 and the ground. As described above, more first sub-adjustable capacitors 121 may be provided;

[0125] Adjusting the adjustable capacitor 12 to the first preset capacitance value includes: adjusting 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 and the second sub-adjustable capacitor 122 are greater than the impedance value of the radio frequency coil 11, for example, 1.2Z coil ;

[0126] Between loading the radio frequency power on the radio frequency coil 11 and determining whether ignition is successful, the processor further performs: adjusting the first tuning capacitor and the second tuning capacitor of the matcher of the semiconductor process equipment for impedance matching so that the radio frequency power is at least loaded on the radio frequency coil 11;

[0127] In the case where ignition is successful, adjusting the adjustable capacitor 12 to the second preset capacitance value includes: 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 is the impedance value of the radio frequency 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, and 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 further performs: adjusting the first tuning capacitor and the second tuning capacitor of the matcher for impedance matching, so that the radio frequency power is at least loaded on the radio frequency coil 11.

[0129] In the case where the ignition is not successful, 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 values of the two first sub-adjustable capacitors 121 and the second sub-adjustable capacitor 122 after reduction, and the preset coefficient is less than 1.

[0130] In the above embodiments of the present invention, the differences between the various embodiments are mainly described. 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 of the text, they will not be elaborated 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 above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit of the present invention and the scope protected by the claims, and all of them fall within the protection scope of the present invention.

Claims

1. An upper electrode device for a process chamber, characterized in that, it includes a radio frequency coil (11) and a tunable capacitor (12). The radio frequency coil (11) is used to wind outside the shielding cylinder (70) of the process chamber, and the shielding cylinder (70) is used to sleeve outside the plasma generation chamber (20) of the process chamber; the tunable capacitor (12) is connected in series with the radio frequency coil (11), and the tunable capacitor (12) is used to be adjusted to different capacitance values during 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 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 through the tunable capacitor (12).

3. The upper electrode device according to claim 2, characterized in that, The adjustable capacitor (12) is at least one, and the impedance value of the adjustable capacitor (12) during the ignition stage is greater than Z coil , where the Z coil is the impedance value of the RF coil (11), and the impedance value of the adjustable capacitor (12) during the reaction stage is greater than 0 and less than Z coil ; or The impedance value of the adjustable capacitor (12) in the reaction stage is greater than 0.4Z coil and less than 0.6Z coil ; or, The impedance value of the adjustable capacitor (12) 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 radio frequency coil (11) is used to be electrically connected to the radio frequency power supply (30) of the process chamber, the second end of the radio frequency coil (11) is used to be grounded, the tunable capacitor (12) includes at least one first sub-tunable capacitor (121), the radio frequency coil (11) includes at least two coil segments connected in series, and each of the first sub-tunable capacitors (121) is connected in series between two adjacent coil segments.

5. The upper electrode device according to claim 4, characterized in that, the tunable capacitor (12) further includes a second sub-tunable capacitor (122), and the second sub-tunable capacitor (122) is used to be connected between the second end of the radio frequency coil (11) and the ground.

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

7. The upper electrode device according to claim 6, characterized in that, there are multiple first sub-tunable capacitors (121), and the impedance values of each of the first sub-tunable capacitors (121) are equal and greater than the impedance value of the second sub-tunable capacitor (122).

8. The upper electrode device according to claim 5, characterized in that, The impedance value of the 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).

9. The upper electrode device according to claim 5, characterized in that, the shielding cylinder (70) is provided with multiple gaps (71) spaced apart along the circumferential direction of the shielding cylinder (70), and the first sub-tunable capacitor (121) and the second sub-tunable capacitor (122) are both misaligned with the gaps (71).

10. The upper electrode device according to claim 1, characterized in that, the upper electrode device (10) further includes a driving mechanism (13), the tunable 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, and 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 the relative area between the first capacitor plate and the second capacitor plate to adjust the capacitance value of the tunable capacitor (12).

11. 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 widths of both ends of the slit (71) are greater than the width of the middle part of the slit (71), and the radio frequency coil (11) is wound outside the middle part.

12. The upper electrode device according to claim 11, characterized in that, the shielding cylinder (70) is provided with a plurality of flared windows (72), the plurality of flared windows (72) communicate with the ends of the plurality of slits (71) in a one-to-one correspondence, and the dimension of the plurality of flared windows (72) in the width direction of the slit (71) is greater than the width of the slit (71).

13. The upper electrode device according to claim 1, characterized in that, the shielding cylinder (70) includes a plurality of grounding parts, the plurality of grounding parts are located at the bottom end of the shielding cylinder (70) and are evenly distributed along the circumferential direction of the shielding cylinder (70).

14. A process chamber, characterized in that, it includes a plasma generation chamber (20), a process reaction chamber, a shielding cylinder (70) and the upper electrode device (10) according to any one of claims 1 to 13, and the process reaction chamber communicates with the plasma generation chamber (20).

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

16. The process chamber according to claim 15, characterized in that, the process chamber further includes a radio frequency power supply (30) and a matcher (40), the radio frequency power supply (30) is electrically connected to the first end of the radio frequency coil (11) through the matcher (40), and the radio frequency power supply (30) and the matcher (40) are located outside the shielding box (80) and are installed on the shielding box (80).

17. A semiconductor processing equipment, characterized in that, it includes a controller and the process chamber according to any one of claims 14 to 16, the controller includes a memory and a processor, the memory stores a computer program, and the processor, according to the computer program, executes the following steps: Adjust the adjustable capacitor (12) to a first preset capacitance value; Load radio frequency power to the radio frequency coil (11) and determine whether ignition is successful; In the case of successful ignition, adjust the adjustable capacitor (12) to a second preset capacitance value, and the second preset capacitance value is greater than the first preset capacitance value.

18. The semiconductor processing equipment according to claim 17, characterized in that, the processor, according to the computer program, further executes the following steps: In the case where ignition is not successful, reduce the capacitance value of the adjustable capacitor (12) and restart the step of determining whether ignition is successful.

19. The semiconductor process equipment according to claim 18, wherein: There is at least one adjustable capacitor (12), where: 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 applying radio frequency power to the radio frequency coil (11) and determining whether ignition is successful, the processor further performs: adjusting the first tuning capacitor and the second tuning capacitor of the matcher of the semiconductor process equipment for impedance matching so that the radio frequency power is at least applied to the radio frequency coil (11); In the case where ignition is successful, adjusting the adjustable capacitor (12) to a 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: adjusting the first tuning capacitor and the second tuning capacitor of the matcher for impedance matching so that the radio frequency power is at least applied to the radio frequency coil (11); In the case where ignition is not successful, reducing the capacitance value of the adjustable capacitor (12) includes: multiplying the current capacitance value of the adjustable capacitor (12) by a preset coefficient as the capacitance value of the adjustable capacitor (12) after reduction, and the preset coefficient is less than 1.

20. The semiconductor process equipment according to claim 18, wherein: The adjustable capacitor (12) includes a plurality of first sub-adjustable capacitors (121) and one 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, and the second sub-adjustable capacitor (122) is used to be connected between the second end of the radio frequency coil (11) and the ground, Adjusting the adjustable capacitor (12) to a first preset capacitance value includes: adjusting the capacitance values of the plurality of first sub-adjustable capacitors (121) and one second sub-adjustable capacitor (122) so that the impedance values of each of the first sub-adjustable capacitors (121) and one second sub-adjustable capacitor (122) are greater than the impedance value of the radio frequency coil (11); Between applying radio frequency power to the radio frequency coil (11) and determining whether ignition is successful, the processor further performs: adjusting the first tuning capacitor and the second tuning capacitor of the matcher of the semiconductor process equipment for impedance matching so that the radio frequency power is at least applied to the radio frequency coil (11); In the case of successful ignition, adjusting the adjustable capacitor (12) to a second preset capacitance value includes: increasing the capacitance values of the plurality of first sub-adjustable capacitors (121) and the second sub-adjustable capacitor (122) so that the impedance value of each of the first sub-adjustable capacitors (121) is Z coil / n, and the impedance value of the second sub-adjustable capacitor (122) is Z coil / 2n, where the Z coil is the impedance value of the radio frequency coil (11), and n is the sum of the number of the first sub-adjustable capacitors (121) and the number of the second sub-adjustable capacitors (122); After adjusting the adjustable capacitor (12) to a second preset capacitance value, the processor further performs: adjusting the first tuning capacitor and the second tuning capacitor of the matcher for impedance matching, so that the radio frequency power is at least loaded on the radio frequency coil (11); In the case where ignition is not successful, reducing the capacitance value of the adjustable capacitor (12) includes: multiplying the current capacitance values of the first sub-adjustable capacitors (121) and the second sub-adjustable capacitors (122) by a preset coefficient as the capacitance values after reduction of the first sub-adjustable capacitors (121) and the second sub-adjustable capacitors (122), and the preset coefficient is less than 1.

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