Radio frequency impedance matching system and semiconductor process equipment

Abstract

The invention provides a radio frequency impedance matching system and semiconductor process equipment. Comprising two orientators with three ports and an echo absorber, the first end of the first orientator and the first end of the second orientator are used for being electrically connected with the output end of a first radio frequency source and the output end of a second radio frequency source respectively, and the frequencies of radio frequency incident signals output by the first radio frequency source and the second radio frequency source are different; the second end of the first orientator and the second end of the second orientator are electrically connected with an electrode device in a process chamber respectively, and the third end of the first orientator and the third end of the second orientator are electrically connected with an echo absorber; the first orientator and the second orientator are configured to enable a radio frequency incident signal to be transmitted from the first end to the electrode device through the second end, and a radio frequency reflected signal to be transmitted from the electrode device to the echo absorber through the second end and the third end. The echo absorber is used for absorbing a radio frequency reflection signal so as to prevent the radio frequency signal from being superposed and aggravated in harmonic wave and IMD frequency due to multiple reflections.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a radio frequency impedance matching system and a semiconductor process equipment. Background Art

[0002] The dual-frequency CCP RF system is usually composed of high-frequency and low-frequency RF power supplies and a dual-frequency matcher, wherein the dual-frequency matcher is used to feed two different frequency signals, high frequency and low frequency, into the process chamber connected to the system, that is, the high-frequency and low-frequency RF power supplies, the dual-frequency matcher and the process chamber can form a loop. However, since the two different frequency signals, high frequency and low frequency, are continuously transmitted and intermodulated in the loop, many harmonics and intermodulation distortion frequency components (IMD) will be generated in the loop, and the harmonics and IMD frequencies will be reflected back and forth in the loop, resulting in multiple superpositions of RF signals, which will cause the power of some frequencies of the RF signal to be very high, even up to 60MHz, which will generate a standing wave effect inside the process chamber, interfere with the distribution of plasma, and affect the uniformity of etching inside the process chamber. Summary of the invention

[0003] The present invention at least partially solves the problem that the existing RF signal reflection superposition affects the etching uniformity of the process chamber, and provides a RF impedance matching system and semiconductor process equipment.

[0004] In a first aspect, an embodiment of the present invention provides a radio frequency impedance matching system, which is applied to semiconductor process equipment, and includes a first director, a second director and an echo absorber; wherein,

[0005] The first director and the second director each have a first end, a second end and a third end, the first ends of the first director and the second director are respectively used to be electrically connected to the output ends of the first RF source and the second RF source, the first RF source and the second RF source output RF incident signal frequencies different; the second ends of the first director and the second director are respectively used to be electrically connected to the electrode device in the process chamber, and the third ends of the first director and the second director are both used to be electrically connected to the echo absorber;

[0006] The first director and the second director are both configured to enable the radio frequency incident signal to be transmitted from the first end to the electrode device via the second end, and the radio frequency reflected signal to be transmitted from the electrode device via the second end and the third end to the echo absorber;

[0007] The echo absorber is used to absorb the radio frequency reflection signal.

[0008] Optionally, the first director and the second director are further configured to enable the radio frequency signal to flow from the third end to the first end;

[0009] The first director and the second director both have an auxiliary path and a switch; one end of the auxiliary path is connected in series with the first end;

[0010] The switching switch is connected in series with the third end; the switching switch is used to connect the other end of the auxiliary path with the third end when receiving a first signal; and the switching switch connects the echo absorber with the third end when receiving a second signal.

[0011] Optionally, it further includes a first power detection unit, a second power detection unit and a control unit;

[0012] The first power detection unit is connected in series between the second end of the first director and the electrode device, and is used to detect the first reflected power, and send the detection result to the control unit; the second power detection unit is connected in series between the second end of the second director and the electrode device, and is used to detect the second reflected power, and send the detection result to the control unit;

[0013] The control unit is used for sending the first signal to the switch in the first director and / or the switch in the second director when the sum of the first reflected power and the second reflected power is greater than a first preset threshold, so as to control at least one of the switches to connect the other end of the auxiliary path with the third end;

[0014] The first preset threshold is the maximum reflected power that the echo absorber can withstand.

[0015] Optionally, the control unit is also used to determine whether the first reflected power is greater than the second reflected power when the sum of the first reflected power and the second reflected power is greater than the first preset threshold; if so, sending the second signal to the switching switch in the second director; if not, sending the second signal to the switching switch in the first director.

[0016] Optionally, the control unit is further configured to control one of the first RF source and the second RF source to be turned on first, and then control the other of the first RF source and the second RF source to be turned on after a first preset time period;

[0017] Alternatively, the control unit is further used to control one of the first RF source and the second RF source to be turned on first, and when the first reflected power or the second reflected power is less than a second preset threshold, control the other of the first RF source and the second RF source to be turned on again.

[0018] Optionally, the control unit is further used to send the second signal to the switching switch in the first director and the switching switch in the second director before the first RF source and the second RF source are turned on, so as to control the switching switch to connect the echo absorber and the third end.

[0019] Optionally, the control unit is also used to send a second signal when the sum of the first reflected power and the second reflected power drops below a third preset threshold, controlling the corresponding switching switch to switch from connecting the other end of the auxiliary path with the third end to connecting the echo absorber with the third end.

[0020] Optionally, after the control unit controls the corresponding switching switch to switch from connecting the other end of the auxiliary path with the third end to connecting the echo absorber with the third end, the control unit is also used to determine whether the first reflected power is less than a fourth preset threshold and whether the second reflected frequency is less than a fifth preset threshold. If both are true, the match is determined to be successful; if not, the match is determined to have failed, and the first RF source and the second RF source are controlled to be turned off.

[0021] Optionally, the RF impedance matching system further includes a low-pass filter and a high-pass filter; one end of the low-pass filter is electrically connected to the one with lower frequency between the first RF source and the second RF source, and the other end is electrically connected to the corresponding first director or the second director; the low-pass filter is used to filter out high-frequency RF signals;

[0022] One end of the high-pass filter is electrically connected to the one with higher frequency between the first RF source and the second RF source, and the other end is electrically connected to the corresponding first director or the second director; the high-pass filter is used to filter out low-frequency RF signals.

[0023] Optionally, it further includes a first matching unit and a second matching unit;

[0024] One end of the first matching unit and the second matching unit are electrically connected to the output end of the low-pass filter and the high-pass filter respectively, and the other end is electrically connected to the first end of the first director and the second director respectively;

[0025] The first matching unit and the second matching unit are used to detect voltage values ​​and current values, and adjust impedance according to the detected voltage values ​​and current values.

[0026] Optionally, the first power detection unit is further used to detect a first incident power, and send the detected first reflected power and the first incident power to the first radio frequency source, and the first radio frequency source is further used to perform working mode control according to the first reflected power and the first incident power;

[0027] The second power detection unit is further used to detect a second incident power, and send the detected second reflected power and the second incident power to the second radio frequency source;

[0028] The second radio frequency source is further used to perform operating mode control according to the second reflected power and the second incident power.

[0029] In a second aspect, an embodiment of the present invention further provides a semiconductor process equipment, which includes a process chamber, an electrode device, a first RF source, a second RF source and the RF impedance matching system as described above; wherein the electrode device is arranged inside the process chamber; the receiving end of the RF impedance matching system is electrically connected to the first RF source and the second RF source respectively, and the output end of the RF impedance matching system is electrically connected to the electrode device.

[0030] The present invention has the following beneficial effects:

[0031] The RF impedance matching system provided by the embodiment of the present invention includes a first director and a second director, both of which have a first end electrically connected to the RF source, a second end electrically connected to the electrode device, and a third end electrically connected to the echo absorber, and the first director and the second director are configured to enable the RF incident signal to flow from the first end to the second end, and the RF reflection signal to flow from the second end to the third end, so as to isolate the input frequency incident signal from the RF reflection signal, and transmit the RF reflection signal to the echo absorber, so as to avoid the RF signal from being superimposed and aggravated by multiple reflections, and thus avoid affecting the uniformity of etching inside the process chamber. Moreover, the echo absorber can simultaneously receive the RF reflection signals output by the two third ends, that is, the first director and the second director can share the same echo absorber, so as to simplify the structure of the RF impedance matching system and reduce the manufacturing cost of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a radio frequency impedance matching system provided by an embodiment of the present invention;

[0033] Figure 2 Another structural schematic diagram of a radio frequency impedance matching system provided by an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the structure of a first director provided in an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the structure of a second director provided by an embodiment of the present invention;

[0036] Figure 5 A flowchart of a work flow of a radio frequency impedance matching system provided by an embodiment of the present invention;

[0037] Figure 6 A flowchart of another working process of the radio frequency impedance matching system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] It should be understood that the specific embodiments and drawings described herein are only used to explain the present invention rather than to limit the present invention.

[0040] It can be understood that, in the absence of conflict, the various embodiments of the present invention and the various features therein can be combined with each other.

[0041] It can be understood that, for the convenience of description, the drawings of the present invention only show the parts related to the embodiments of the present invention, while the parts unrelated to the embodiments of the present invention are not shown in the drawings.

[0042] It can be understood that, in the absence of conflict, the functions and steps marked in the flowcharts and block diagrams of the embodiments of the present invention may occur in an order different from that marked in the drawings.

[0043] Please refer to Figure 1 This embodiment provides a radio frequency impedance matching system applied to semiconductor process equipment, which includes a first director 3, a second director 4 and an echo absorber 5.

[0044] Wherein, the first director 3 and the second director 4 each have a first end a, a second end b and a third end c; the first end a of the first director 3 and the second director 4 is respectively used to be electrically connected to the output end of the first RF source 1 and the second RF source 2; the second end b of the first director 3 and the second director 4 is respectively used to be electrically connected to the electrode device in the process chamber, for example, to the upper electrode and / or the lower electrode; the third end c of the first director 3 and the second director 4 is both used to be electrically connected to the echo absorber. The first director 3 and the second director 4 are both configured to enable the RF incident signal to be transmitted unidirectionally from the first end a to the second end b and then to the electrode device of the semiconductor process equipment, and to enable the RF reflection signal to be transmitted unidirectionally from the electrode device to the echo absorber 5 via the second end b and the third end c, so as to isolate the RF incident signal from the RF reflection signal, thereby preventing the RF reflection signal from flowing back into the RF source and causing damage to the RF source.

[0045] The echo absorber 5 is used to absorb the RF reflection signal output by the two third ends c, thereby absorbing the RF reflection signal reflected by the electrode device to avoid interfering with the input RF signal expected by the process, and can prevent the RF reflection signal from continuing to reflect in the RF loop, thereby avoiding multiple superpositions of harmonics and IMD frequencies in the RF signal, and thus ensuring that no standing wave effect occurs inside the process chamber, avoiding affecting the uniformity of etching inside the process chamber. Moreover, the two directors share the same echo absorber 5, which can save equipment costs and avoid wasting space.

[0046] However, if Figure 2 As shown, the number of the echo absorbers 5 may also be two, and the two echo absorbers 5 are respectively used to electrically connect the third ends c of the first director 3 and the second director 4 .

[0047] The first RF source 1 and the second RF source 2 output RF incident signal frequencies that are different. Specifically, one of them may be a low-frequency RF source, and the other may be a high-frequency RF source. For example, the first RF source 1 is a low-frequency source in a dual-frequency RF system, and is used to output RF signals of 13 MHz, 2 MHz or 400 kHz. The second RF source 2 is a high-frequency source in a dual-frequency RF system, and is used to output RF signals of 40 MHz or 60 MHz.

[0048] In some embodiments, the first director 3 and the second director 4 are further configured to enable the radio frequency signal to flow from the third end c to the first end a. Figure 3 and Figure 4As shown, the first orienter 3 and the second orienter 4 both have auxiliary paths (31, 41) and switching switches (32, 42); one end of the two auxiliary paths (31, 41) is connected in series with the corresponding first end a. The two switching switches (32, 42) are connected in series with the corresponding third end c; the switching switches are used to connect the other end of the auxiliary paths (31, 41) with the third end c when receiving the first signal, so that the radio frequency reflection signal entering from the second end b can flow from the third end c to the first end a, and can also enter the first end a through the auxiliary path 31, thereby preventing the radio frequency reflection signal from entering the echo absorber 5, so that when the power of the radio frequency reflection signal exceeds the maximum power that the echo absorber 5 can withstand, the echo absorber 5 can be prevented from being damaged due to overload; when receiving the second signal, the switching switches (32, 42) connect the echo absorber 5 with the third end c, so that the radio frequency reflection signal entering from the second end b can flow from the third end c into the echo absorber 5, so that the radio frequency reflection signal can be absorbed.

[0049] Since the RF impedance matching system proposed in this embodiment is provided with the first director 3 and the second director 4, the reflected power of the RF reflected signal may directly enter the echo absorber 5, but cannot reach the reflected power detection unit of the first RF source 1 and the second RF source 2, resulting in the inability to know the RF reflected power. In order to solve this problem, in some embodiments, such as Figure 1 As shown, the RF impedance matching system also includes a first power detection unit 8, a second power detection unit 9 and a control unit (not shown in the figure). The first power detection unit 8 is connected in series between the second end b of the first director 3 and the electrode device, and is used to detect the first reflected power of the RF reflected signal, and send the detection result to the control unit; the second power detection unit 9 is connected in series between the second end b of the second director 4 and the electrode device, and is used to detect the second reflected power of the RF reflected signal, and send the detection result to the control unit.

[0050] The control unit is used to send a first signal to the switching switch 32 in the first director 3 and / or the switching switch 42 in the second director 4 when the sum of the first reflected power and the second reflected power is greater than a first preset threshold, wherein the first preset threshold is the maximum reflected power that the echo absorber can withstand, so as to control at least one switching switch to connect the other end of the corresponding auxiliary path with the corresponding third end c, thereby reducing or stopping the transmission to the echo absorber, thereby avoiding damage to the echo absorber 5 due to overload.

[0051] In some embodiments, the first power detection unit 8 is also used to detect the first incident power, and send the detected first reflected power and the first incident power to the first RF source, and the first RF source is also used to perform working mode control according to the first reflected power and the first incident power. The second power detection unit 9 is also used to detect the second incident power, and send the detected second reflected power and the second incident power to the second RF source; the second RF source is also used to perform working mode control according to the second reflected power and the second incident power. Specifically, "working mode control" refers to controlling the RF signal output method of the RF source. For example, in the same signal cycle, the RF source can output a higher-power RF signal in the High level stage, and output a lower-power RF signal in the Low level stage, and then perform frequency sweep matching in the High level stage or the Low level stage.

[0052] In some specific implementations, the control unit may be configured to calculate the sum of the first reflected power and the second reflected power, and execute the step of determining whether the sum of the first reflected power and the second reflected power is greater than a first preset threshold.

[0053] Furthermore, in some embodiments, the control unit is further configured to determine whether the first reflected power is greater than the second reflected power when the sum of the first reflected power and the second reflected power is greater than a first preset threshold; if so, a second signal is sent to the switch 42 in the second director 4 to connect the switch 42 to the third end c of the second director 4 and the echo absorber 5; if not, a second signal is sent to the switch 32 in the first director 3 to connect the switch 32 to the third end c of the second director 4 and the echo absorber 5. In this way, the RF reflected signal with a smaller reflected power can be returned to the corresponding RF source to avoid damage to the RF source while avoiding overloading of the echo absorber 5.

[0054] In some embodiments, the control unit is also used to control one of the first RF source 1 and the second RF source 2 to turn on first, and then control the other of the first RF source 1 and the second RF source 2 to turn on after a first preset time period, that is, the high-frequency RF signal matching and the low-frequency RF signal matching are started at different times and the start time intervals are fixed, so that the starting time of the same process is fixed, thereby ensuring the consistency of multiple processes and ensuring process efficiency.

[0055] Alternatively, in some other embodiments, the control unit is also used to control one of the first RF source 1 and the second RF source 2 to be turned on first, and when the first reflected power or the second reflected power is less than the second preset threshold, control the other of the first RF source 1 and the second RF source 2 to be turned on again; if not, a judgment is made every second preset time; that is, to ensure that the high-frequency RF signal matching or the low-frequency RF signal matching is stable, and then another matching process is performed, so that the subsequent matching process can be easier to start, and a higher frequency RF reflection signal will not be generated during the matching process. Specifically, the above-mentioned second preset threshold is much smaller than the above-mentioned first preset threshold.

[0056] In actual production, the above two matching modes of the RF impedance matching system can be selected according to actual process conditions such as process conditions, process requirements, the specific matching speed of the RF impedance matching system, and whether the automatic frequency fine-tuning function (AFC) of the semiconductor process equipment is turned on, so that the equipment can work in a stable and safe environment.

[0057] In some embodiments, the control unit is also used to send a second signal to the switching switch 32 in the first director 3 and the switching switch 42 in the second director 4 before the first RF source 1 and the second RF source 2 are turned on, so as to control the switching switches to connect the echo absorber 5 and the third end c, that is, to initialize the RF impedance matching system before the RF source is turned on, so as to keep the echo absorber 5 in a state where it can receive the RF reflection signals in the two circuits.

[0058] In some embodiments, the control unit is further configured to send a second signal to the two switches (32, 42) when the sum of the first reflected power and the second reflected power decreases below a third preset threshold, and control the corresponding switches to switch their working state from connecting the other end of the auxiliary path (31, 41) with the third end c to connecting the echo absorber 5 with the third end c. Specifically, the third preset threshold is, for example, 1 / 2 of the first preset threshold.

[0059] In some embodiments, after the control unit controls the corresponding switching switch (32, 42) to switch from connecting the other end of the auxiliary path with the third end c to connecting the echo absorber 5 with the third end c, the control unit is also used to determine whether the first reflected power is less than a fourth preset threshold and whether the second reflected frequency is less than a fifth preset threshold. If both are true, the matching is determined to be successful; if not, the matching is determined to have failed, and the first RF source and the second RF source are controlled to be turned off.

[0060] In some embodiments, the control device is also used to continuously calculate the number of judgments while performing the above judgment steps, and judge whether it reaches a preset number of times; if so, it is judged that the matching fails, and the first RF source and the second RF source are controlled to be turned off. This is to avoid damage to the equipment due to too long matching time, and it can also timely eliminate the problem of too long matching time caused by equipment failure. Specifically, the above preset number of times can be determined according to the actual test results of the RF impedance matching system and the semiconductor process equipment.

[0061] Based on the above-mentioned radio frequency impedance matching system, this embodiment further specifically provides two working processes of the radio frequency impedance matching system. Figure 5 As shown, the first workflow includes the following steps:

[0062] S11: sending a second signal to the two switching switches (32, 42) so that the two third ends c are connected to the echo absorber 5;

[0063] S12: First turn on the first RF source 1, and after a delay of t1, turn on the second RF source 2; (or, first turn on the second RF source 2, and after a delay of t1, turn on the first RF source 1;)

[0064] S13: after a delay of t2, determine whether the sum of the first reflected power and the second reflected power is greater than a first preset threshold value (the maximum reflected power Pmax that the echo absorber can withstand); if so, proceed to step S14; if not, proceed to step S17;

[0065] S14: Compare the first reflected power and the second reflected power; if the first reflected power is larger, send a second signal to the switch 42 of the second director 4 to connect the auxiliary path 41 with the third end c; if the second reflected power is larger, send a second signal to the switch 32 of the first director 3 to connect the auxiliary path 31 with the third end c;

[0066] S15: after a delay of t3, continue to determine whether the sum of the first reflected power and the second reflected power is less than a third preset threshold value; if so, send a first signal to the two switches (32, 42) so that the ends of the two auxiliary paths (31, 41) are connected to the corresponding third end c, and proceed to step S17; if not, continue to perform step S15 once, and perform a count once;

[0067] S16: Continue to determine whether the number of times the above step S15 is performed reaches a first preset number of times; when the first preset number of times is reached, it is determined that the matching fails, and the first RF source 1 and the second RF source 2 are both turned off, and the process ends;

[0068] S17: after a delay of t4, determine whether the first reflected power is less than the fourth preset threshold, and determine whether the second reflected power is less than the fifth preset threshold; if both are yes, determine that the match is successful, and start the process steps; if at least one of the judgment results is no, continue to step S17 once, and count once;

[0069] S18: Continue to determine whether the number of times the above step S17 is performed reaches a second preset number; when the first preset number is reached, it is determined that the matching fails, and the first RF source 1 and the second RF source 21 are controlled to be turned off, and the process ends.

[0070] like Figure 6 As shown, the second workflow includes the following steps:

[0071] S21: sending a second signal to the two switches (32, 42) so that the two third ends c are electrically connected to the echo absorber 5;

[0072] S22: first turn on the first RF source 1, and after a delay of t5, determine whether the first reflected power is less than the second preset threshold (or first turn on the second RF source 2, and after a delay of t5, determine whether the second reflected power is less than the sixth preset threshold; specifically, when the output power of the second RF source 2 is different from that of the first RF source 1, the corresponding sixth preset threshold is not equal to the second preset threshold); if so, proceed to step S24; if not, continue to delay t5, perform the above-mentioned judgment process again, and perform a count;

[0073] S23: Continue to determine whether the number of times the above step S22 is performed reaches a third preset number of times; when the third preset number of times is reached, it is determined that the matching fails, and the first RF source 1 and the second RF source 2 are both turned off, and the process ends;

[0074] S24: Turn on the second RF source 2 (if the first RF source 1 is turned on first in step S22, this step is to turn on the first RF source 1);

[0075] S25: after a delay of t2, determine whether the sum of the first reflected power and the second reflected power is greater than a first preset threshold; if so, proceed to step S26; if not, proceed to step S29;

[0076] S26: Compare the first reflected power and the second reflected power; if the first reflected power is larger, send a second signal to the switch 42 of the second director to connect the auxiliary path 41 with the third end c; if the second reflected power is larger, send a second signal to the switch 32 of the first director 3 to connect the auxiliary path 31 with the third end c;

[0077] S27: After a delay of t3, continue to determine whether the sum of the first reflected power and the second reflected power is less than a third preset threshold; if so, send a first signal to the two switches and proceed to step S29; if not, continue to perform step S27 once and perform a count;

[0078] S28: Continue to determine whether the number of times the above step S27 is performed reaches a first preset number of times; when the first preset number of times is reached, it is determined that the matching fails, and the first RF source 1 and the second RF source 2 are both turned off, and the process ends;

[0079] S29: after a delay of t4, determine whether the first reflected power is less than the fourth preset threshold, and determine whether the second reflected power is less than the fifth preset threshold; if both are yes, determine that the match is successful, and start the process steps; if at least one of the judgment results is no, continue to step S29 once, and count once;

[0080] S30: Continue to determine whether the number of times the above step S29 is performed reaches a second preset number; when the first preset number is reached, it is determined that the matching fails, and the first RF source 1 and the second RF source 2 are controlled to be turned off, and the process ends.

[0081] It should be noted that the above-mentioned parameters such as the first to sixth preset thresholds of signal power, delay time t1 to 4 and the first to third preset times can be designed according to actual process conditions, process requirements, RF impedance matching system component parameters and semiconductor process equipment component parameters.

[0082] In some embodiments, Figure 1 As shown, the RF impedance matching system also includes two filters, which are specifically divided into a low-pass filter and a high-pass filter; one end of the low-pass filter is electrically connected to the first RF source and the second RF source with a lower frequency, and the other end is electrically connected to the corresponding first director or the second director; the low-pass filter is used to filter out high-frequency RF signals; one end of the high-pass filter is electrically connected to the first RF source and the second RF source with a higher frequency, and the other end is electrically connected to the corresponding first director or the second director; the high-pass filter is used to filter out low-frequency RF signals.

[0083] In some embodiments, Figure 1 As shown, the RF impedance matching system also includes a first matching unit 6 and a second matching unit 7. One end of the first matching unit 6 and the second matching unit 7 are electrically connected to the output ends of the low-pass filter and the high-pass filter, respectively, and the other end is electrically connected to the corresponding first director 3 or second director 4. The first matching unit 6 and the second matching unit 7 are used to detect voltage values ​​and current values, and adjust the impedance on the circuit according to the detected voltage values ​​and current values.

[0084] Specifically, in some embodiments, Figure 1 As shown, the first matching unit 6 and the second matching unit 7 both include impedance detectors, and the output ends of the two detectors are respectively electrically connected to the first end a of the first director 3 and the first end a of the second director 4. The two impedance detectors are respectively used to detect the voltage value and the current value in the circuit, so as to calculate the impedance value in the circuit according to the voltage value and the current value.

[0085] As shown in the figure, the first matching unit 6 and the second matching unit 7 also include two adjustable capacitors; Figure 1 As shown, one end of an adjustable capacitor C1 is electrically connected to the corresponding low-pass filter or high-pass filter, and the other end is electrically connected to the input end of the corresponding first impedance detection unit or second impedance detection unit; one end of another adjustable capacitor C2 is electrically connected to the corresponding low-pass filter or high-pass filter, and the other end is grounded. In the RF matching stage, the capacitance values ​​of the above-mentioned multiple adjustable capacitors can be adjusted respectively until impedance matching is achieved.

[0086] As another technical solution, this embodiment also provides a semiconductor process equipment, which includes a process chamber, an electrode device, a first RF source, a second RF source, and the RF impedance matching system as described above. The electrode device is arranged inside the process chamber; the receiving end of the RF impedance matching system is electrically connected to the first RF source and the second RF source respectively, and the output end of the RF impedance matching system is electrically connected to the electrode device, and the RF impedance matching system is used to transmit the RF signal to the electrode device.

[0087] Specifically, the receiving end of the RF impedance matching system can be electrically connected to the corresponding RF source through a coaxial cable. The RF impedance matching system is placed after the coaxial cable, and the transmission path of the RF reflection signal is only transmitted from the process chamber to the first director and the second director, and then to the echo absorber. The transmission path is very short and the superposition probability is reduced, thereby effectively reducing the harmonic and IMD power.

[0088] The above-mentioned RF impedance matching system and semiconductor process equipment proposed in this embodiment, by connecting the first director and the second director in series in the low-frequency and high-frequency circuits, and providing an echo absorber connected to the first director and the second director, can transmit low-frequency and high-frequency RF signals to the electrode device and use the echo absorber to absorb the RF reflected signal, thereby avoiding the RF signal from being superimposed and aggravated by multiple reflections, thereby avoiding affecting the uniformity of etching inside the process chamber.

[0089] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A radio frequency impedance matching system, applied to semiconductor process equipment, characterized in that: It includes a first director, a second director and an echo absorber; wherein, The first director and the second director each have a first end, a second end and a third end, the first ends of the first director and the second director are respectively used to be electrically connected to the output ends of the first RF source and the second RF source, the first RF source and the second RF source output RF incident signal frequencies different; the second ends of the first director and the second director are respectively used to be electrically connected to the electrode device in the process chamber, and the third ends of the first director and the second director are both used to be electrically connected to the echo absorber; The first director and the second director are both configured to enable the radio frequency incident signal to be transmitted from the first end to the electrode device via the second end, and the radio frequency reflected signal to be transmitted from the electrode device via the second end and the third end to the echo absorber; The echo absorber is used to absorb the radio frequency reflection signal.

2. The radio frequency impedance matching system according to claim 1, characterized in that: The first director and the second director are further configured to enable the radio frequency signal to flow from the third end to the first end; The first director and the second director both have an auxiliary path and a switch; one end of the auxiliary path is connected in series with the first end; The switching switch is connected in series with the third end; the switching switch is used to connect the other end of the auxiliary path with the third end when receiving a first signal; and the switching switch connects the echo absorber with the third end when receiving a second signal.

3. The radio frequency impedance matching system according to claim 2, characterized in that: Also includes a first power detection unit, a second power detection unit and a control unit; The first power detection unit is connected in series between the second end of the first director and the electrode device, and is used to detect the first reflected power, and send the detection result to the control unit; the second power detection unit is connected in series between the second end of the second director and the electrode device, and is used to detect the second reflected power, and send the detection result to the control unit; The control unit is used for sending the first signal to the switch in the first director and / or the switch in the second director when the sum of the first reflected power and the second reflected power is greater than a first preset threshold, so as to control at least one of the switches to connect the other end of the auxiliary path with the third end; The first preset threshold is the maximum reflected power that the echo absorber can withstand.

4. The radio frequency impedance matching system according to claim 3, characterized in that: The control unit is also used to determine whether the first reflected power is greater than the second reflected power when the sum of the first reflected power and the second reflected power is greater than the first preset threshold; if so, send the second signal to the switching switch in the second director; if not, send the second signal to the switching switch in the first director.

5. The radio frequency impedance matching system according to claim 3, characterized in that: The control unit is further configured to control one of the first RF source and the second RF source to be turned on first, and then control the other of the first RF source and the second RF source to be turned on after a first preset time period; Alternatively, the control unit is further used to control one of the first RF source and the second RF source to be turned on first, and when the first reflected power or the second reflected power is less than a second preset threshold, control the other of the first RF source and the second RF source to be turned on again.

6. The radio frequency impedance matching system according to claim 5, characterized in that: The control unit is further configured to send the second signal to the switch in the first director and the switch in the second director before the first RF source and the second RF source are turned on, so as to control the switch to connect the echo absorber and the third end.

7. The radio frequency impedance matching system according to claim 3, characterized in that: The control unit is also used to send a second signal when the sum of the first reflected power and the second reflected power drops below a third preset threshold, controlling the corresponding switching switch to switch from connecting the other end of the auxiliary path with the third end to connecting the echo absorber with the third end.

8. The radio frequency impedance matching system according to claim 3, characterized in that: After the control unit controls the corresponding switching switch to switch from connecting the other end of the auxiliary path with the third end to connecting the echo absorber with the third end, the control unit is further used to determine whether the first reflected power is less than a fourth preset threshold and whether the second reflected frequency is less than a fifth preset threshold. If both are true, the matching is determined to be successful; if not, the matching is determined to have failed, and the first RF source and the second RF source are controlled to be turned off.

9. The radio frequency impedance matching system according to claim 1, characterized in that: The RF impedance matching system further includes a low-pass filter and a high-pass filter; one end of the low-pass filter is electrically connected to the one with lower frequency between the first RF source and the second RF source, and the other end is electrically connected to the corresponding first director or the second director; the low-pass filter is used to filter out high-frequency RF signals; One end of the high-pass filter is electrically connected to the one with higher frequency between the first RF source and the second RF source, and the other end is electrically connected to the corresponding first director or the second director; the high-pass filter is used to filter out low-frequency RF signals.

10. The radio frequency impedance matching system according to claim 9, characterized in that: Also includes a first matching unit and a second matching unit; One end of the first matching unit and the second matching unit are electrically connected to the output end of the low-pass filter and the high-pass filter respectively, and the other end is electrically connected to the first end of the first director and the second director respectively; The first matching unit and the second matching unit are used to detect voltage values ​​and current values, and adjust impedance according to the detected voltage values ​​and current values.

11. The radio frequency impedance matching system according to claim 3, characterized in that: The first power detection unit is further used to detect a first incident power, and send the detected first reflected power and the first incident power to the first radio frequency source, and the first radio frequency source is further used to control the working mode according to the first reflected power and the first incident power; The second power detection unit is further used to detect a second incident power, and send the detected second reflected power and the second incident power to the second radio frequency source; The second radio frequency source is further used to perform operating mode control according to the second reflected power and the second incident power.

12. A semiconductor process equipment, characterized in that: It includes a process chamber, an electrode device, a first RF source, a second RF source and a RF impedance matching system as described in any one of claims 1 to 11; wherein the electrode device is arranged inside the process chamber; the receiving end of the RF impedance matching system is electrically connected to the first RF source and the second RF source respectively, and the output end of the RF impedance matching system is electrically connected to the electrode device.

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