TW201939569A - Plasma radio frequency adjustment method and plasma processing device capable of quickly adjusting the frequency and finding the radio frequency power corresponding to the minimum reflected power - Google Patents

Abstract

The present invention discloses a plasma radio frequency (RF) adjustment method. The adjustment method is performed by an RF power generator. The RF power generator includes an automatic frequency modulation device. The RF power generator outputs a pulse RF signal. A controller is configured with plural continuous radio frequency adjustment intervals, each radio frequency adjustment interval having at least one pulse radio frequency period. The automatic frequency modulation device performs at least one automatic frequency modulation in each of the radio frequency adjustment intervals. Each radio frequency adjustment interval includes a start frequency and an end frequency. The start frequency of each radio frequency adjustment interval is the end frequency of the previous radio frequency adjustment interval. The start frequency of the first radio frequency adjustment interval is a preset frequency. With the method of the present invention, it is able to quickly adjust the frequency, and quickly find the radio frequency power corresponding to the minimum reflected power for the pulse radio frequency period.

Description

Method for adjusting plasma radio frequency and plasma processing device

The invention relates to a plasma radio frequency adjustment method and a plasma processing device, and more particularly, to a technical field of matching adjustment for supplying pulsed radio frequency power to a plasma processing device.

In conventional semiconductor processing, plasma processing equipment is widely used to process semiconductor wafers to obtain micro-sized semiconductor components and conductor connections. Plasma devices commonly include capacitively coupled (CCP) and inductively coupled (ICP) reaction chambers. These devices generally have two RF power sources, one of which is used to ionize the reaction gas flowing into the reaction chamber to generate a plasma. Another RF power source is used to control the energy of the ions incident on the wafer surface.

At present, many plasma processing processes require the use of pulsed plasma processing technology. That is, the radio frequency power supply in some process periods is not continuously powered but switched on-off alternately or high-power-low power radio frequency alternately. The waveform is pulsed, so it is called pulsed plasma processing. The pulse frequency of the pulsed RF signal is usually greater than 100HZ. The duty cycle of the pulsed signal can be set within the range of 10% -90% as required. Each time it is turned on, turned off, or switched between high-power and low-power, the impedance in the reaction chamber changes rapidly, and the time of each change is in the millisecond or even microsecond range. Under this kind of demand, the traditional use of matching circuits due to the response time Far from reaching the millisecond level, it is difficult to meet the requirements of pulsed plasma processing.

Therefore, based on the above reasons, the industry needs a technology capable of satisfying high-frequency pulse RF period matching.

In order to solve the above technical problems, the present invention provides a plasma radio frequency adjustment method, which is performed by a radio frequency power generator, the radio frequency power generator includes an automatic frequency adjustment device, and the adjustment method includes the following steps: The radio frequency power generator outputs a pulse radio frequency period; sets a plurality of continuous radio frequency adjustment intervals, each radio frequency adjustment interval includes at least one pulse radio frequency period; the automatic frequency modulation device performs at least one automatic frequency adjustment in each of the radio frequency adjustment intervals, Each radio frequency adjustment interval includes a start frequency and an end frequency. The start frequency of each radio frequency adjustment interval is the end frequency of the previous radio frequency adjustment interval, and the start frequency of the first radio frequency adjustment interval is a preset frequency.

Further, the starting frequency includes a starting high-level frequency and a starting low-level frequency, and the ending frequency includes an ending high-level frequency and an ending low-level frequency.

Further, the automatic frequency modulation method is as follows: the radio frequency power generator is given a preset frequency corresponding to obtaining the first reflected power, and the preset frequency is increased by one step to the radio frequency power generator correspondingly to obtain the second reflected power. , Comparing the first reflected power and the second reflected power, if the second reflected power is greater than the first reflected power, increase the step size in the opposite direction, and if the second reflected power is less than the first reflected power, continue to reduce the It is assumed that the frequency power is increased by two steps to give the radio frequency power generator to adjust to obtain smaller reflected power.

Further, the preset frequency is a frequency capable of ensuring plasma ignition.

Further, the method for obtaining the preset frequency is: setting a radio frequency power source to output a continuous radio frequency power signal, and calculating and obtaining a minimum reflected power in the continuous radio frequency output stage, and using the frequency corresponding to the minimum reflected power as a preset frequency.

Further, each radio frequency adjustment interval includes at least two pulsed radio frequency periods, and the automatic frequency modulation device performs a plurality of automatic frequency modulations in each pulsed radio frequency period. The automatic frequency modulation device has the same start frequency and end frequency in different pulse radio frequency periods of the same radio frequency adjustment interval.

Further, the automatic frequency modulation device has the same start frequency and different end frequency in different pulsed radio frequency periods of the same radio frequency adjustment interval.

Further, the time of the radio frequency adjustment interval is set by a controller.

Further, the controller reads an end frequency of the automatic frequency modulation device and assigns the end frequency as a start frequency of a next radio frequency adjustment interval to the automatic frequency modulation device.

Further, the controller sets a reflection power threshold, and when the reflection power found by the automatic frequency modulation device is lower than the reflection power threshold, the frequency modulation process stops.

Further, the duration of the radio frequency adjustment interval is greater than or equal to 1 millisecond.

Preferably, the duration of the radio frequency adjustment interval is 10 milliseconds.

Preferably, the duration of the radio frequency adjustment interval is 50 milliseconds.

Preferably, the duration of the radio frequency adjustment interval is 100 milliseconds.

Preferably, the duration of the radio frequency adjustment interval is 150 milliseconds.

Preferably, the duration of the radio frequency adjustment interval is 200 milliseconds.

Further, the frequency modulation time of the automatic frequency modulation device is greater than or equal to 0.1 microsecond.

Preferably, the frequency modulation time of the automatic frequency modulation device is 1 microsecond.

Preferably, the frequency modulation time of the automatic frequency modulation device is 5 microseconds.

Preferably, the frequency modulation time of the automatic frequency modulation device is 10 microseconds.

Preferably, the frequency modulation time of the automatic frequency modulation device is 20 microseconds.

Preferably, the frequency modulation time of the automatic frequency modulation device is 30 microseconds.

Further, the pulse signal is high-low level, and the low level is greater than or equal to zero.

The method according to the present invention can realize frequency modulation matching of a radio frequency power generator with a pulse frequency of a pulse radio frequency greater than 100 Hz.

The method of the invention can realize the frequency modulation matching of a radio frequency power generator with a pulse frequency of a pulse radio frequency period greater than 5000 Hz.

Further, the present invention discloses a plasma processing apparatus, the apparatus includes:

A plasma processing chamber for receiving and processing a wafer;

A radio frequency power generator applied to the plasma processing chamber for generating or adjusting plasma;

A controller acting on the radio frequency power generator for controlling the duration of a radio frequency adjustment interval;

The radio frequency power generator outputs a pulse radio frequency period; each radio frequency adjustment interval includes at least one pulse radio frequency period;

The radio frequency power generator includes an automatic frequency modulation device. The automatic frequency modulation device performs automatic frequency modulation at least once in each pulsed radio frequency cycle. Each radio frequency adjustment interval includes a start frequency and an end frequency. The start frequency of the interval is the end frequency of the previous radio frequency adjustment interval, and the start frequency of the first radio frequency adjustment interval is a preset frequency.

Further, the starting frequency includes a starting high-level frequency and a starting low-level frequency, and the ending frequency includes an ending high-level frequency and an ending low-level frequency.

Further, the preset frequency is a first preset frequency, and the preset frequency includes a high-level preset frequency and a low-level preset frequency, and the high-level preset frequency is a continuous RF power generator. The frequency corresponding to the minimum reflected power during high power output, and the low-level preset frequency is the frequency corresponding to the minimum reflected power during continuous low power output by the RF power generator.

Further, the preset frequency is given to the automatic frequency modulation device by the controller.

Further, the processing device includes a second radio frequency power generator, and the second radio frequency power generator outputs a second pulsed radio frequency signal.

Further, the second radio frequency power generator includes a second automatic frequency modulation device; the second automatic frequency modulation device performs automatic frequency modulation at least once in each of the radio frequency adjustment intervals, and each of the radio frequency adjustment intervals includes a start Frequency and an end frequency, the start frequency of each radio frequency adjustment interval is the end frequency of the previous radio frequency adjustment interval, and the start frequency of the first radio frequency adjustment interval is a second preset frequency.

Preferably, the frequency modulation time of the automatic frequency modulation device is greater than or equal to 0.1 microsecond.

Preferably, the controller controls the duration of the radio frequency adjustment interval to be greater than or equal to 1 millisecond.

Further, the controller controls the durations of the multiple consecutive radio frequency adjustment intervals to be the same or different.

Further, the pulsed radio frequency signal further includes a third-level power state, and the third-level power is between the high-level power and the low-level power. The frequency matching method of the third-level power is the same as the frequency matching method of the high-level power state and the low-level power state.

The invention discloses a plasma radio frequency adjustment method and a plasma processing device. By using an automatic frequency adjustment device provided in a radio frequency power generator, a controller defines a radio frequency adjustment interval to cooperate with the automatic frequency adjustment device, and can match without changing. In the case of a transmitter, the pulse output frequency of the RF power generator is quickly adjusted. Because the frequency of the automatic frequency modulation device does not need to be adjusted with regard to mechanical hardware, the frequency modulation time can be reduced to 0.1 microseconds, so that the minimum reflected power can be quickly found. Corresponding frequency. The frequency modulation method according to the present invention is particularly effective in regulating high-frequency pulse signals.

The radio frequency matching adjustment method disclosed by the present invention is applicable to any plasma processing device that needs fast radio frequency matching, such as a plasma etching processing device. The common plasma etching processing device includes a capacitively coupled plasma processing device and an inductive coupling. For the convenience of description of the plasma processing apparatus, the present invention will be described in detail below with reference to the drawings, taking a capacitively coupled plasma processing apparatus as an example.

FIG. 1 discloses a capacitive coupling plasma processing device, which includes a reaction chamber 100. The reaction chamber includes a base 22, and the base includes a lower electrode. Above the lower electrode, a wafer fixing device such as an electrostatic chuck 21 is mounted. The wafer 20 is fixed on the upper surface of the electrostatic chuck 21. An edge ring 10 is also included around the electrostatic chuck and wafer. The reaction chamber 100 also includes a gas shower head 11 above the base opposite to the base. The gas shower head is connected to the gas source 110 for uniformly supplying gas into the reaction chamber. The gas shower head simultaneously acts as an upper electrode to form a capacitive coupling with the lower electrode in the base. A first radio frequency power generator 30 is electrically connected to the lower electrode through the matcher 1. Optionally, the plasma processing apparatus further includes a second radio frequency power generator 40 electrically connected to the lower electrode through the matcher 2. The first radio frequency power generator 30 and the second radio frequency power generator 40 can output continuous radio frequency signals, and can also output pulse radio frequency periods. Each RF power generator has a predetermined frequency value. Since the impedance of the plasma will change with changes in parameters such as the pressure in the plasma, RF power, and plasma concentration, the RF power generator needs to be continuously adjusted. Output frequency to minimize reflected power.

When the RF power generator outputs a continuous and stable RF signal, if other parameters in the reaction chamber do not change, the matcher will perform RF matching on the continuous RF signal within a certain period of time to obtain the RF frequency corresponding to the minimum reflected power. In the stable manufacturing process, the radio frequency power generator is instructed to output a radio frequency corresponding to the minimum reflected power.

When the RF power generator outputs a pulsed RF signal, the RF power applied to the reaction chamber is switched between low-high level or on-off state. At this time, the plasma environment in the reaction chamber will change accordingly. The RF frequency that produces the minimum reflected power also changes constantly. In particular, when the pulse signal has a pulse frequency greater than 100 Hz, the matcher cannot be quickly switched due to hardware conditions (such as mechanically driven variable capacitors or variable inductors), and it is not possible to match the switching of the pulse signal.

In the present invention, the radio frequency power generator includes an automatic frequency modulation device. The automatic frequency modulation device can perform multiple frequency modulations on the pulsed radio frequency signal in each pulsed radio frequency period to find a radio frequency corresponding to the minimum reflected power. In addition, the present invention also includes a controller 50. The controller 50 outputs a radio frequency adjustment interval signal, and each radio frequency adjustment interval has a duration of T, including at least one pulse radio frequency period.

As shown in Figure 2-Figure 4, Figure 2 shows a pulsed RF signal from the RF power generator. Within a RF adjustment interval T, it can include multiple pulsed RF cycles. In the same process, RF adjustment The duration of the interval T may be the same or different. Generally, in order to reduce the calculation amount of the controller 50, the same RF adjustment interval is used in the same process. FIG. 3 shows a schematic diagram of frequency adjustment of an automatic frequency modulation device. In each pulsed RF period, the automatic frequency modulation device performs multiple automatic frequency modulation steps. The automatic frequency modulation method is specifically: the controller first assigns the RF power generator. A preset frequency corresponding to obtaining the first reflected power, and increasing the preset frequency by one step to the radio frequency power generator, corresponding to obtaining the second reflected power, comparing the first reflected power and the second reflected power, if the second If the reflected power is greater than the first reflected power, increase the step size in the opposite direction. If the second reflected power is less than the first reflected power, continue to increase the preset frequency by two steps to the radio frequency power generator, and continuously obtain Smaller reflected power. The frequency modulation time of the automatic frequency modulation device is the time required to obtain a reflected power for each additional step. The automatic frequency modulation time can be set to 0.1 microsecond or more, preferably 0.1 microsecond, 1 microsecond, 5 microseconds, 10 microseconds. 15 microseconds, 20 microseconds or 30 microseconds.

During the frequency modulation process of the automatic frequency modulation device, since the plasma environment in the reaction chamber constantly changes, the RF adjustment of each pulse RF period is not the same in the same RF adjustment interval. This means that even if the same start frequency is assigned to each pulse radio frequency period, the end frequency of each pulse radio frequency period is not necessarily the same. If the pulse radio frequency cycle time is long enough and the frequency modulation time of the automatic frequency modulation device is short enough, the minimum reflected power can be found in one pulse radio frequency cycle, different pulse radio frequency cycles in the same radio frequency adjustment interval may also have the same end frequency. In order to ensure the continuity of radio frequency adjustment, the end frequency of the last pulse radio frequency period of a radio frequency adjustment interval is usually selected as the end frequency of the entire radio frequency adjustment interval.

The automatic frequency modulation device includes a start frequency and an end frequency in a radio frequency adjustment interval. Due to the length of an RF adjustment interval, it is difficult for the automatic frequency modulation device to find the frequency corresponding to the minimum reflected power in a radio frequency adjustment interval. Therefore, Frequency modulation needs to be performed in multiple consecutive RF adjustment intervals. The frequency modulation method is to assign the radio frequency power generator a preset frequency f ₀ as a starting frequency in the first radio frequency adjustment interval, and assign the end frequency f _{1 of the} first radio frequency adjustment interval to the radio frequency power generator as a second frequency. The starting frequency of the RF adjustment interval, and so on, until the frequency corresponding to the minimum reflected power is obtained. During the frequency modulation process, the controller sets a reflected power threshold value. When the reflected power found by the automatic frequency modulation device is smaller than the reflected power threshold value, the assignment frequency modulation process ends. When the impedance or condition changes in the reaction chamber causes the reflected power to be higher than the threshold, the assignment frequency modulation process restarts.

Since a pulsed RF signal includes a high level and a low level, the start frequency includes a start high frequency and a start low frequency, and the end frequency includes an end high frequency and an end low power. Flat frequency. According to the frequency modulation method described above, the end high level frequency of the previous RF adjustment interval is used as the start high level frequency of the next RF adjustment interval, and the end low level frequency of the previous RF adjustment interval is used as the Start low frequency. Combining with FIG. 3, it is specifically to determine the start high-level frequency f ₀ (h) and the start low-level frequency f ₀ (l) of the first radio frequency adjustment interval, and in each pulse radio frequency period of the first radio frequency adjustment interval Repeatedly search for the frequency corresponding to the minimum reflected power from the starting high-level frequency f ₀ (h) and the starting low-level frequency f ₀ (l), and obtain the frequency f corresponding to the smaller reflected power at the end of the first RF adjustment interval. ₁ (h) and f ₁ (l), because the duration of the RF adjustment interval is limited, the smaller reflected power obtained at the end of the first RF adjustment interval may not be the minimum reflected power. Therefore, in the second RF adjustment interval, The automatic frequency modulation device continues to perform automatic frequency modulation. At this time, the frequencies f ₁ (h) and f ₁ (l) corresponding to the smaller reflected power obtained at the end of the previous RF adjustment interval are used as the starting high-frequency and starting low-frequency. And obtain the end high-level frequency f ₂ (h) and the end low-level frequency f ₂ (l) at the end of the second RF adjustment interval, and continue to serve as the start high-frequency and start low power of the subsequent RF adjustment interval. Flat frequency.

There are multiple methods for determining the start frequency of the first radio frequency adjustment interval, as long as the frequency at which the plasma can be ignited can be used as the start frequency. In a common embodiment, since the RF power generator usually outputs pulsed RF power after outputting continuous RF power for a certain period of time, when the frequency corresponding to the minimum reflected power of the pulsed RF power is adjusted, the first RF adjustment interval starts. The frequency may be a frequency corresponding to the minimum reflected power in the continuous RF output stage, and the frequency is given to the RF power generator by the controller 50.

Since the RF power source can include a high-level power state and a low-level power state, one method of determining the start frequency of the high-level power state is to set the RF power generator to output continuous high-level power states and obtain the minimum reflected power corresponding to Frequency, a method for determining the starting frequency of a low-level power state is to set the RF power generator to output a continuous low-level power state and obtain the frequency corresponding to the minimum reflected power.

By adopting the above frequency modulation method, the output frequency of the RF power generator can be quickly adjusted without changing the matcher. Since the frequency of the automatic frequency modulation device does not need to be adjusted with regard to mechanical hardware, the frequency modulation time can be reduced to 0.1 microseconds. For a 100-Hz pulse signal, assuming that the duty cycle of the pulse signal is 50%, within a pulse radio frequency period, the automatic frequency modulation device can adjust the frequency 50,000 times, and the frequency corresponding to the minimum reflected power can be quickly found.

The frequency modulation method according to the present invention is particularly effective in regulating high-frequency pulse signals. When the pulse frequency of the pulsed radio frequency signal reaches 5000 Hz, the rate of high and low level switching of the radio frequency signal is very fast, and the duration of each pulse radio frequency period is only 200 Microsecond, assuming that the frequency modulation time of the automatic frequency modulation device is 10 microseconds each time, and the duty cycle of the pulse signal is 50%, the automatic frequency modulation device can perform 10 times for high frequency and low frequency in each pulse RF cycle. For the secondary frequency search, the duration of the RF adjustment interval is set to 10 milliseconds. In 1 s, the automatic frequency adjustment device can perform 1000 RF adjustments, so it can quickly find the RF power corresponding to the minimum reflected power.

The controller 50 can control the duration of each radio frequency adjustment interval. The shorter the duration, the shorter the time for the radio frequency power generator to find the minimum reflected power, which is more conducive to the stability and accuracy of the plasma processing process. What needs to be considered is that the shorter the length of the RF adjustment interval means the larger the data that the controller needs to process, the faster the speed. Therefore, it needs to be comprehensively considered according to the accuracy requirements of the plasma processing process. Preferably, the duration of the RF adjustment interval is greater than or equal to 1 millisecond, and the duration of the commonly used RF adjustment interval is one of the following: 10 ms, 50 ms, 100 ms, 150 ms, 200 ms, 250 ms, 300 ms Wait.

Although the content of the present invention has been described in detail through the above-mentioned preferred embodiments, it should be recognized that the above description should not be considered as limiting the present invention. Various modifications and alternatives to the present invention will be apparent to those skilled in the art after reading the foregoing. Therefore, the protection scope of the present invention should be defined by the scope of the attached patent application.

1, 2‧‧‧ Matcher

10‧‧‧ edge ring

100‧‧‧ reaction chamber

11‧‧‧Gas shower head

110‧‧‧Air source

20‧‧‧Chip

21‧‧‧ electrostatic chuck

22‧‧‧ base

30‧‧‧First RF Power Generator

40‧‧‧Second RF Power Generator

50‧‧‧controller

Other features, objects, and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings: FIG. 1 shows a schematic structural diagram of a plasma processing apparatus; FIG. 2 Fig. 3 shows a schematic diagram of a pulse signal output by a radio frequency power generator; Fig. 3 shows a schematic diagram of frequency modulation performed by an automatic frequency modulation device; Fig. 4 shows a schematic diagram of a reflection power curve corresponding to the frequency adjustment of the automatic frequency modulation device.

Claims (36)

A plasma radio frequency adjustment method is performed by a radio frequency power generator. The radio frequency power generator includes an automatic frequency modulation device. The plasma radio frequency adjustment method includes the following steps. The radio frequency power generator outputs a pulse. Radio frequency signal; setting a plurality of continuous radio frequency adjustment intervals, each of which includes at least one pulse radio frequency cycle; the automatic frequency modulation device performs at least one automatic frequency adjustment in each of the radio frequency adjustment intervals, and each of the radio frequency adjustment intervals includes one A start frequency and an end frequency. The start frequency of each RF adjustment interval is the end frequency of the previous RF adjustment interval, and the start frequency of the first RF adjustment interval is a preset frequency. The plasma radio frequency adjustment method according to item 1 of the scope of patent application, wherein the start frequency includes a start high frequency and a start low frequency, and the end frequency includes an end high frequency and an end low power. Flat frequency. According to the plasma radio frequency adjustment method described in item 1 of the scope of patent application, wherein the method of automatic frequency modulation is: giving the radio frequency power generator the preset frequency corresponding to obtaining the first reflected power, and increasing the preset frequency by one step The radio frequency power generator is given correspondingly to obtain a second reflected power, and the first reflected power and the second reflected power are compared. If the second reflected power is greater than the first reflected power, the step size is increased in the opposite direction. If the second reflected power is smaller than the first reflected power, the preset frequency is further increased by two steps to the radio frequency power generator, and a smaller reflected power is obtained by adjusting. The plasma radio frequency adjustment method according to item 3 of the scope of the patent application, wherein the preset frequency is a frequency capable of ensuring plasma ignition. The plasma radio frequency adjustment method as described in item 3 of the scope of patent application, wherein the method for obtaining the preset frequency is: setting a radio frequency power source to output continuous radio frequency power signals, and calculating and obtaining the minimum reflected power in the continuous radio frequency output stage, The frequency corresponding to the reflected power is used as the preset frequency. The plasma radio frequency adjustment method according to item 1 of the patent application range, wherein each radio frequency adjustment interval includes at least two pulsed radio frequency periods, and the automatic frequency modulation device performs a plurality of automatic frequency modulations in each pulsed radio frequency period. The plasma radio frequency adjustment method according to item 6 of the patent application scope, wherein the automatic frequency modulation device has the same start frequency and end frequency in different pulse radio frequency periods of the same radio frequency adjustment interval. The plasma radio frequency adjustment method according to item 6 of the patent application scope, wherein the automatic frequency modulation device has the same start frequency and different the end frequency in different pulse radio frequency periods of the same radio frequency adjustment interval. The plasma radio frequency adjustment method according to item 1 of the patent application range, wherein the time of the radio frequency adjustment interval is set by a controller. The plasma radio frequency adjustment method according to item 9 of the scope of patent application, wherein the controller reads the end frequency of the automatic frequency modulation device and assigns the end frequency as the start frequency of the next radio frequency adjustment interval to the automatic frequency adjustment Device. According to the plasma RF adjustment method described in item 9 of the scope of the patent application, wherein the controller sets a reflection power threshold, and when the reflection power found by the automatic frequency modulation device is lower than the reflection power threshold, the frequency modulation process is stopped. The plasma radio frequency adjustment method according to item 1 of the scope of patent application, wherein the duration of the radio frequency adjustment interval is greater than or equal to 1 millisecond. The plasma radio frequency adjustment method according to item 12 of the scope of the patent application, wherein the duration of the radio frequency adjustment interval is 10 milliseconds. The plasma radio frequency adjustment method according to item 12 of the application, wherein the duration of the radio frequency adjustment interval is 50 milliseconds. The plasma radio frequency adjustment method according to item 12 of the scope of the patent application, wherein the duration of the radio frequency adjustment interval is 100 milliseconds. The plasma radio frequency adjustment method according to item 12 of the patent application scope, wherein the duration of the radio frequency adjustment interval is 150 milliseconds. The plasma radio frequency adjustment method according to item 12 of the patent application scope, wherein the duration of the radio frequency adjustment interval is 200 milliseconds. The plasma radio frequency adjustment method according to item 1 of the scope of the patent application, wherein the frequency modulation time of the automatic frequency modulation device is greater than or equal to 0.1 microsecond. The plasma radio frequency adjustment method according to item 18 of the scope of patent application, wherein the frequency modulation time of the automatic frequency modulation device is 1 microsecond. The plasma radio frequency adjustment method according to item 18 of the scope of the patent application, wherein the frequency modulation time of the automatic frequency modulation device is 5 microseconds. The plasma radio frequency adjustment method according to item 18 of the scope of patent application, wherein the frequency modulation time of the automatic frequency modulation device is 10 microseconds. The plasma radio frequency adjustment method according to item 18 of the scope of the patent application, wherein the frequency modulation time of the automatic frequency modulation device is 20 microseconds. The plasma radio frequency adjustment method according to item 18 of the scope of patent application, wherein the frequency modulation time of the automatic frequency modulation device is 30 microseconds. The plasma radio frequency adjustment method according to item 1 of the patent application range, wherein the pulsed radio frequency signal includes high-level power and low-level power, and the low-level power is greater than or equal to zero. The plasma RF adjusting method according to item 24 of the patent application scope, wherein the pulsed RF signal further includes a third-level power state, the third-level power is between the high-level power and the low-level power between. The plasma radio frequency adjustment method according to item 1 of the scope of the patent application, wherein the pulse frequency of the pulsed radio frequency period is greater than 100 Hz. The plasma radio frequency adjustment method according to item 1 of the scope of the patent application, wherein the pulse frequency of the pulse radio frequency period is greater than 5000 Hz. A plasma processing apparatus includes: a plasma processing chamber for receiving and processing a wafer; a radio frequency power generator applied to the plasma processing chamber for generating or regulating a plasma; a controller for functioning The radio frequency power generator is used to control the duration of a radio frequency adjustment interval; the radio frequency power generator outputs a pulse radio frequency signal, and each radio frequency adjustment interval includes at least one pulse radio frequency cycle; the radio frequency power generator includes an automatic frequency modulation Device, the automatic frequency modulation device performs automatic frequency modulation at least once in each pulsed radio frequency cycle, each radio frequency adjustment interval includes a start frequency and an end frequency, and the start frequency of each radio frequency adjustment interval is the previous radio frequency adjustment The end frequency of the interval, and the start frequency of the first RF adjustment interval is a preset frequency. The plasma processing apparatus according to item 28 of the scope of patent application, wherein the start frequency includes a start high frequency and a start low frequency, and the end frequency includes an end high frequency and an end low level. frequency. The plasma processing device according to item 28 of the patent application scope, wherein the preset frequency includes a high-level preset frequency and a low-level preset frequency, and the high-level preset frequency is a continuous range of the RF power generator. The frequency corresponding to the minimum reflected power at high power output. The low-level preset frequency is the frequency corresponding to the minimum reflected power of the RF power generator during continuous low power output. The plasma processing apparatus according to item 28 of the scope of patent application, wherein the preset frequency is given to the automatic frequency modulation apparatus by the controller. The plasma processing apparatus according to item 28 of the application, wherein the plasma processing apparatus includes a second RF power generator, and the second RF power generator outputs a second pulsed RF signal. The plasma processing device according to item 28 of the patent application scope, wherein the second radio frequency power generator includes a second automatic frequency modulation device, and the second automatic frequency modulation device performs automatic frequency modulation at least once in each of the radio frequency adjustment intervals. The radio frequency adjustment intervals include the start frequency and the end frequency. The start frequency of each radio frequency adjustment interval is the end frequency of the previous radio frequency adjustment interval, and the start frequency of the first radio frequency adjustment interval is the first. Two preset frequencies. The plasma processing device according to item 28 of the scope of the patent application, wherein the frequency modulation time of the automatic frequency modulation device is greater than or equal to 0.1 microsecond. The plasma processing apparatus according to item 28 of the scope of the patent application, wherein the controller controls the duration of the radio frequency adjustment interval to be greater than or equal to 1 millisecond. The plasma processing device according to item 28 of the scope of patent application, wherein the controller controls a plurality of consecutive RF adjustment intervals with the same or different durations.