Semiconductor process equipment and pulse signal control method

Abstract

The present invention provides semiconductor processing equipment and a pulse signal control method. The semiconductor processing equipment includes a process chamber, an upper electrode and a lower electrode, a square wave power supply, and two radio frequency power supplies. The upper electrode and the lower electrode are vertically arranged relative to each other in the process chamber, and the lower electrode is used to support a wafer. The two radio frequency power supplies have different frequencies and are used to output radio frequency continuous signals or radio frequency pulse signals. One of the two radio frequency power supplies is connected to the lower electrode, and the other is connected to the lower electrode or the upper electrode. The square wave power supply is connected to the upper electrode and is used to output a pulse voltage signal with a variable frequency. The semiconductor processing equipment and pulse signal control method provided by the present invention can adjust the etching profile during a plasma etching process to obtain an etching profile with a high aspect ratio and vertical sidewalls.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a semiconductor process equipment and a pulse signal control method. Background Art

[0002] The dual-frequency capacitively coupled plasma (CCP) etching process is widely used in microelectronics processing due to its high etch rate advantages, enabling high aspect ratio etching. The power source typically uses two RF power supplies with different RF frequencies: the higher-frequency RF power supply is used to generate a high density of ions and radicals, while the lower-frequency RF power supply is used to generate a bias voltage that accelerates ion etching. In addition to the RF power supply, a DC power supply is typically also configured to apply a bias voltage to the top electrode. This bias voltage not only helps reduce the formation of deposits but also has a variety of effects on the plasma density, distribution, and potential.

[0003] However, existing DC power supplies can only output a continuous voltage signal in the same process step, or obtain a voltage signal with a consistent output frequency through controller modulation. During the plasma etching process, they cannot be used to adjust the etching profile, especially to obtain an etching profile with a high aspect ratio and vertical sidewalls. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a semiconductor process equipment and a pulse signal control method, which can adjust the etching morphology during the plasma etching process to obtain an etching morphology with a high aspect ratio and vertical side walls.

[0005] To achieve the purpose of the present invention, a semiconductor process equipment is provided, comprising a process chamber, an upper electrode and a lower electrode, a square wave power supply and two radio frequency power supplies, wherein:

[0006] The upper electrode and the lower electrode are arranged opposite to each other in the process chamber in a vertical direction, and the lower electrode is used to support the wafer; the two RF power supplies have different frequencies and are used to output RF continuous signals or RF pulse signals, one of the two RF power supplies is connected to the lower electrode, and the other is connected to the lower electrode or the upper electrode, and the square wave power supply is connected to the upper electrode for outputting a pulse voltage signal with a variable frequency.

[0007] Optionally, the period of the pulse voltage signal is a first period, the pulse voltage signal has a first frequency, the first period includes a first time period and a second time period, and in the first time period, the pulse voltage signal has a second frequency.

[0008] Optionally, the ratio of the first time period to the second time period is greater than or equal to 10% and less than or equal to 90%, and / or, in the first time period, the duty cycle of the pulse voltage signal is greater than or equal to 10% and less than or equal to 90%.

[0009] Optionally, the second frequency is greater than or equal to 2 KHz and less than or equal to 400 KHz; and / or the first frequency is greater than or equal to 1 KHz and less than or equal to 50 KHz.

[0010] Optionally, both of the RF power supplies are connected to the lower electrode and are used to output RF pulse signals; the period of the RF pulse signal with a higher frequency is the second period, and the period of the RF pulse signal with a lower frequency is the third period, wherein the signal output time period of the second period is synchronized with the first time period.

[0011] Optionally, the signal output period in the second cycle is synchronized with the signal output period in the third cycle; or, the signal output period in the second cycle has a preset delay time relative to the signal output period in the third cycle, and the signal output period in the second cycle precedes the signal output period in the third cycle.

[0012] Optionally, the preset delay time is greater than or equal to half of the time of the signal output period in the second cycle, and less than or equal to the time of the signal output period in the second cycle.

[0013] Optionally, the process chamber further includes a grounded conductive component, and the conductive component is configured to be in contact with the plasma.

[0014] Optionally, the conductive component includes a component constituting a chamber wall of the process chamber, or a focusing ring arranged on the lower electrode, wherein the focusing ring surrounds the periphery of the wafer and is electrically insulated from the lower electrode.

[0015] Optionally, there are multiple square wave power supplies, one of which is connected to the upper electrode, and the remaining square wave power supplies are respectively connected to different conductive components.

[0016] As another technical solution, the present invention also provides a pulse signal control method, which is applied to semiconductor process equipment, wherein the semiconductor process equipment includes a square wave power supply and two radio frequency power supplies, one of the two radio frequency power supplies is connected to the lower electrode, and the other is connected to the lower electrode or the upper electrode, and the square wave power supply is connected to the upper electrode; the pulse signal

[0017] Control methods include:

[0018] Controlling one of the two radio frequency power supplies to output a radio frequency continuous signal or a radio frequency pulse signal;

[0019] At the same time, controlling the other of the two radio frequency power supplies to output a radio frequency continuous signal or a radio frequency pulse signal;

[0020] At the same time, the square wave power supply is controlled to output a pulse voltage signal with a variable frequency;

[0021] The two radio frequency power sources have different frequencies.

[0022] Optionally, the period of the pulse voltage signal is a first period, the pulse voltage signal has a first frequency, the first period includes a first time period and a second time period, and in the first time period, the pulse voltage signal has the second frequency;

[0023] Controlling the square wave power supply to output a pulse voltage signal with a variable frequency includes controlling the pulse voltage signal to change from the second frequency to the first frequency.

[0024] The present invention has the following beneficial effects:

[0025] In the technical solutions for the semiconductor process equipment and pulse signal control method provided by the present invention, two RF power supplies have different frequencies and are used to output either continuous or pulsed RF signals. One of the two RF power supplies is connected to the lower electrode, while the other is connected to either the lower or upper electrode. A square-wave power supply is connected to the upper electrode and is used to output a pulse voltage signal with a variable frequency. Thus, during a plasma etching process, by combining the square-wave power supply with at least one of the two RF power supplies and utilizing the variable-frequency pulse voltage signal outputted by the square-wave power supply, the etching profile can be adjusted, thereby achieving an etching profile with a high aspect ratio and vertical sidewalls. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The waveform diagram of the pulse voltage signal with the same output frequency as the existing square wave power supply;

[0027] Figure 2 A schematic structural diagram of a semiconductor process equipment provided by an embodiment of the present invention;

[0028] Figure 3 This is a waveform diagram of a pulse voltage signal with a variable frequency output by a square wave power supply used in an embodiment of the present invention;

[0029] Figure 4 This is a waveform diagram of the radio frequency continuous signal output by two radio frequency power supplies used in an embodiment of the present invention;

[0030] Figure 5 A waveform diagram of radio frequency pulse signals output by two radio frequency power supplies used in an embodiment of the present invention;

[0031] Figure 6 Another waveform diagram of the radio frequency pulse signals output by the two radio frequency power supplies used in the embodiment of the present invention;

[0032] Figure 7 A waveform diagram of two RF power supplies outputting RF pulse signals and a square wave power supply outputting variable frequency pulse voltage signals used in an embodiment of the present invention;

[0033] Figure 8A A schematic diagram of an etched morphology obtained by performing a plasma etching process on a semiconductor process equipment in which the upper electrode is not connected to a square wave power supply;

[0034] Figure 8B The semiconductor process equipment with the upper electrode connected to the square wave power supply used in the embodiment of the present invention adopts Figure 7 A schematic diagram of an etching morphology obtained by performing a plasma etching process using the pulse signal control method shown;

[0035] Figure 9 Another waveform diagram of two RF power supplies outputting RF pulse signals and a square wave power supply outputting variable frequency pulse voltage signals used in an embodiment of the present invention;

[0036] Figure 10 A schematic diagram of another structure of semiconductor process equipment provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solution of the present invention, the semiconductor process equipment and the pulse signal control method provided by the present invention are described in detail below with reference to the accompanying drawings.

[0038] See also Figure 2 An embodiment of the present invention provides a semiconductor process apparatus comprising a process chamber 1, an upper electrode 2, a lower electrode 3, a square wave power supply 6, and two radio frequency power supplies 4, wherein the upper electrode 2 and the lower electrode 3 are vertically disposed relative to each other in the process chamber 1. Optionally, a gas inlet is disposed at the top of the process chamber 1. In this case, the upper electrode 2, in addition to serving as an electrode, can also serve as a gas homogenizing device, capable of homogenizing the process gas entering the process chamber 1 through the gas inlet.

[0039] The two RF power supplies 4 have different frequencies (i.e., RF frequencies) and are used to output RF continuous signals or RF pulse signals. The higher-frequency RF power supply 4 is used to generate high-density ions and free radicals, and the RF frequency of the RF power supply 4 is, for example, 40 MHz; the lower-frequency RF power supply is used to form a bias voltage that can accelerate ion etching, and the RF frequency of the RF power supply 4 is, for example, 13.36 MHz. Both RF power supplies 4 can be connected to the lower electrode 3 through a matcher 5, but the embodiment of the present invention is not limited to this. In actual applications, one of the two RF power supplies 4 can be connected to the lower electrode 3, and the other can be connected to the lower electrode 3 or the upper electrode 2.

[0040] The square wave power supply 6 is connected to the upper electrode 2 and is used to output a pulse voltage signal of variable frequency to the upper electrode 2. The voltage signal is a DC voltage signal. In some optional embodiments, Figure 3 The waveform diagram of the pulse voltage signal with variable frequency output by the square wave power supply used in the embodiment of the present invention is shown in FIG. Figure 3 As shown, the period of the variable frequency pulse voltage signal output by the square wave power supply 6 is a first period T3, and the pulse voltage signal has a first frequency (1 / T3). The first period T3 includes a first time period t31 and a second time period t32. In the first time period t31, the pulse voltage signal has a second frequency (1 / Tm). Specifically, in the first time period t31, the period of the pulse voltage signal is Tm, and the period Tm includes a signal output time period (i.e., an on time period when the voltage is not 0V) tm1 and a signal off time period (i.e., an off time period when the voltage is 0V) tm2; and in the second time period t32, the pulse voltage signal is always in a signal off state (off state). In this way, the pulse voltage signal has two frequencies, i.e., the first frequency and the second frequency, which are called variable frequency pulse voltage signals. Of course, in actual applications, according to different process requirements, other variable frequency pulse voltage signals can also be used, and the embodiment of the present invention has no special restrictions on this.

[0041] In some optional embodiments, the square wave power supply 6 may be connected to the upper electrode 2 via a radio frequency filter 7 , and the radio frequency filter 7 is used to prevent the frequency of the radio frequency power supply 4 from interfering with the square wave power supply 6 .

[0042] During the plasma etching process, when used in combination with at least one of the two RF power supplies 4, a variable-frequency pulse voltage signal is outputted to the upper electrode 2 by the square wave power supply 6, thereby forming a bias voltage on the upper electrode 2. This bias voltage is generally a negative voltage (-V). Taking the example of a negative voltage (-V) applied by the square wave power supply 6 to the upper electrode 2, applying a negative bias voltage to the upper electrode 2 can generate more electrons, thereby increasing the plasma sheath (i.e., the negatively charged region) generated by the upper electrode 2, thereby compressing the plasma and reducing the distribution area of ​​the plasma in the process chamber 1, thereby helping to improve the plasma density and process uniformity.

[0043] Moreover, loading a negative bias voltage on the upper electrode 2 can also increase the absolute value of the self-bias voltage of the upper electrode 2, thereby improving the sputtering effect of the plasma on the surface of the upper electrode 2 and reducing the accumulation of attachments on the surface of the upper electrode 2. In some optional embodiments, the process chamber 1 also includes a grounded conductive component, which is used to contact the plasma, and is, for example, a component constituting the chamber wall of the process chamber 1, or a focusing ring 8 provided on the lower electrode 3, which surrounds the periphery of the wafer and is electrically insulated from the lower electrode 3. In this case, optionally, the above-mentioned square wave power supply 6 can also be multiple, one of which is connected to the upper electrode 2, and the remaining square wave power supplies 6 can be respectively connected to different conductive components, and the conductive component can also achieve the above-mentioned cleaning effect by loading a negative bias voltage with the help of the square wave power supply 6 connected thereto. For example, Figure 10 As shown, there are two square wave power supplies 6 , one of which is connected to the upper electrode 2 , and the other is connected to the focusing ring 8 .

[0044] During the plasma etching process, two RF power supplies 4 can be used in combination with the square wave power supply 6, or one of the RF power supplies 4 can be used in combination with the square wave power supply 6. When in use, the RF power supply 4 can output a continuous RF signal or a pulsed RF signal. If two RF power supplies 4 are used simultaneously, both RF power supplies 4 can output a continuous RF signal or a pulsed RF signal. Alternatively, one RF power supply 4 can output a continuous RF signal while the other outputs a pulsed RF signal. The square wave power supply 6 outputs a pulsed voltage signal of variable frequency, which can be used in combination with either the continuous RF signal or the pulsed RF signal output by at least one RF power supply 4 to meet different process requirements.

[0045] By combining a square wave power supply 6 with at least one of the two RF power supplies 4 and outputting a variable-frequency pulse voltage signal with the square wave power supply 6, the etching profile can be adjusted, thereby obtaining an etching profile with a high aspect ratio and vertical sidewalls. Specifically, the etching profile can be adjusted by adjusting one or a combination of parameters, including the ratio of the first time period t31 to the second time period t32, the duty cycle of the pulse voltage signal during the first time period t31, the first frequency (1 / T3), and the second frequency (1 / Tm), to obtain an etching profile with a high aspect ratio and vertical sidewalls.

[0046] In some optional embodiments, the ratio of the first time period t31 to the second time period t32 is greater than or equal to 10% and less than or equal to 90%; and / or, in the first time period t31, the duty cycle of the pulse voltage signal is greater than or equal to 10% and less than or equal to 90%.

[0047] In some optional embodiments, the first frequency (1 / T3) is greater than or equal to 1 KHz and less than or equal to 50 KHz; and / or the second frequency (1 / Tm) is greater than or equal to 2 KHz and less than or equal to 400 KHz.

[0048] In practical applications, when at least one of the two RF power supplies 4 outputs a continuous RF signal, Figure 4 As shown, the RF power supply 4 with a higher frequency continuously outputs the RF pulse signal with a waveform such as Figure 4 (a) As shown; the waveform of the RF continuous signal output by the RF power supply 4 with a lower frequency is as follows Figure 4 (b) shown.

[0049] At least one of the two RF power supplies 4 can also output a RF pulse signal. When both RF power supplies 4 output RF pulse signals, Figure 5 As shown, the waveform of the RF pulse signal output by the RF power supply 4 with a higher frequency is as follows. Figure 5 As shown in (a), the period is the second period T1, which includes a signal output period (i.e., an on period when the voltage is not 0V) t11 and a signal off period (i.e., an off period when the voltage is 0V) t12; the waveform of the RF pulse signal output by the RF power supply 4 with a lower frequency is as follows. Figure 5 As shown in (b), its period is the third period T2, and the third period T2 includes a signal output period (i.e., an on period when the voltage is not 0V) t21 and a signal off period (i.e., an off period when the voltage is 0V) t22. Optionally, the signal output period t11 of the second period T1 can be synchronized with the signal output period t21 of the third period T2, that is, the two RF power supplies 4 output signals synchronously.

[0050] Alternatively, the two RF power supplies 4 may also output signals asynchronously. There are many ways to output signals asynchronously, for example, Figure 6 As shown, the signal output period t11 in the second cycle T1 has a preset delay time Δt relative to the signal output period t21 in the third cycle T2. Specifically, the start time of the signal output period t11 in the second cycle T1 precedes the start time of the signal output period t21 in the third cycle T2, and the time interval between the two is Δt. Optionally, the preset delay time Δt is greater than or equal to half the time of the signal output period t11 in the second cycle T1, and less than or equal to the time of the signal output period t11 in the second cycle T1. In this way, the higher-frequency RF power supply 4 outputs the RF pulse signal first, and after more than half the time of the signal output period t11 in the second cycle T1, the lower-frequency RF power supply 4 begins to output the RF pulse signal. This ensures that after a sufficient density of plasma has been generated, the lower-frequency RF power supply 4 is used to attract the plasma toward the wafer surface, effectively restricting the incident angle of the plasma and facilitating the formation of an etched feature with a high aspect ratio and vertical sidewalls. At the same time, the above-mentioned preset delay time Δt should be less than or equal to the time of the signal output period t11 in the second cycle T1, so as to ensure that the two RF power supplies 4 jointly output RF pulse signals for at most half of the time of the signal output period t11 in the second cycle T1 to meet the process requirements.

[0051] In practical applications, for the case where the two RF power supplies 4 output signals asynchronously, the duty cycle of the signal output period t11 in the second cycle T1 (the percentage of t11 to T1) and the duty cycle of the signal output period t21 in the third cycle T2 (the percentage of t21 to T2) can be the same or different.

[0052] The following describes in detail a specific embodiment of the use of a square wave power supply 6 in combination with two radio frequency power supplies 4. Figure 9 As shown, two RF power supplies 4 are connected to the lower electrode 3 and are used to output RF pulse signals. In addition, the signal output period t11 of the second cycle T1 is synchronized with the first period t31. Optionally, the signal output period t11 of the second cycle T1 can also be synchronized with the signal output period t21 of the third cycle T2. In this case, the square wave power supply 6 outputs signals synchronously with the two RF power supplies 4 and stops outputting signals synchronously. This setting can achieve the following effects:

[0053] Figure 8A A schematic diagram of an etched morphology obtained by performing a plasma etching process on a semiconductor process equipment in which the upper electrode is not connected to a square wave power supply; Figure 8B The semiconductor process equipment with the upper electrode connected to the square wave power supply used in the embodiment of the present invention adopts Figure 7Schematic diagram of the etching morphology obtained by performing plasma etching process using the pulse signal control method shown. Figure 8A and Figure 8B It can be seen that Figure 8B The plasma formed in Figure 8A The plasma formed in the process is compressed, which helps to reduce the distribution area of ​​the plasma in the process chamber 1, thereby helping to improve the plasma density, process uniformity, etc. At the same time, a protective layer 102 can be deposited on the mask 101. The protective layer 102 can protect the etching morphology of the mask 101, thereby helping to improve the etching morphology of the etched layer 103 and obtain better process results. Figure 8A When a semiconductor process equipment in which the upper electrode is not connected to a square wave power supply performs a plasma etching process, the protective layer 102 cannot be formed.

[0054] Moreover, if Figure 8B As shown, if the pulse voltage signal output by the square wave power supply 6 is fed into the upper electrode 2 from a position close to the center, more electrons are generated in the central area of ​​the process chamber than in the edge area, and the density of the plasma distribution in the central area is higher than that in the edge area, thereby increasing the etching rate in the central area of ​​the process chamber to compensate for the difference in etching rate between the central area and the edge area of ​​the process chamber, thereby improving the etching uniformity.

[0055] In addition, during the second period t32 when the square wave power supply 6 has no signal output, which is also the signal-off period t12 and t22 when the two RF power supplies 4 have no signal output, the reaction gas in the process chamber 1 does not participate in dissociation, and no positive ions are etched at this time. During this stage, a large number of electrons or negatively charged ions will neutralize with the positive ions when they reach the bottom of the groove or hole. These positive ions were dissociated from the reaction gas in the process chamber 1 during the first period t31 when the square wave power supply 6 has a signal output, which is also the signal output period t11 and t21 when the two RF power supplies 4 have a signal output. The micro-discharge generated by these positive ions will damage the morphology of the groove or hole. Therefore, by removing the positive ions remaining at the bottom of the groove or hole during the signal-off period t32 when the square wave power supply 6 has no signal output, the process results can be effectively improved.

[0056] When performing a plasma etching process for trenches or holes, under the premise that the process conditions (pressure, gas type, power, temperature, etc.) meet the process requirements, the square wave power supply 6 specifically adopts the following parameters, namely: the ratio of the first time period t31 to the second time period t32 in the first cycle T3 is 40%; the first frequency (1 / T3) is 10kHz; in the first time period t31, the duty cycle of the pulse voltage signal is 50%; the second frequency (1 / Tm) is 400kHz. Figure 8B As shown, compared to Figure 8AThe etched morphology obtained by the plasma etching process of the semiconductor process equipment whose upper electrode is not connected to the square wave power supply. The semiconductor process equipment used in the embodiment of the present invention combines the square wave power supply 6 with the two RF power supplies 4 and adopts the above-mentioned parameters to perform the plasma etching process. The side walls of the obtained grooves or holes are smoother and more vertical. This effect is more obvious in the process of grooves or holes with an aspect ratio of 30:1 or more, thereby obtaining an etched morphology with a high aspect ratio and vertical side walls.

[0057] It should be noted that, in the above embodiment, the signal output period t11 in the second cycle T1, the signal output period t21 in the third cycle T2 and the first period t31 in the first cycle T3 are synchronized (start and stop at the same time). However, the embodiment of the present invention is not limited to this. In actual applications, for example, Figure 9 As shown, on the basis of the synchronization between the signal output period t11 of the second cycle T1 and the first period t31, the signal output period t11 in the second cycle T1 has a preset delay time Δt relative to the signal output period t21 in the third cycle T2. This asynchronous method has been described in detail above and will not be repeated here.

[0058] As another technical solution, an embodiment of the present invention further provides a pulse signal control method, which is applied to the above-mentioned semiconductor process equipment provided by an embodiment of the present invention. Figure 2 Taking the semiconductor process equipment shown as an example, the semiconductor process equipment includes a process chamber 1, an upper electrode 2 and a lower electrode 3, a square wave power supply 6 and two RF power supplies 4, wherein the two RF power supplies 4 have different frequencies and are used to output RF continuous signals or RF pulse signals. The higher-frequency RF power supply 4 is used to generate high-density ions and free radicals, and the RF frequency of the RF power supply 4 is, for example, 40 MHz; the lower-frequency RF power supply is used to form a bias voltage that can accelerate ion etching, and the RF frequency of the RF power supply 4 is, for example, 13.36 MHz. Both RF power supplies 4 can be connected to the lower electrode 3 through a matcher 5, but the embodiment of the present invention is not limited to this. In actual applications, one of the two RF power supplies 4 can be connected to the lower electrode 3, and the other can be connected to the lower electrode 3 or the upper electrode 2.

[0059] The pulse signal control method includes:

[0060] Control one of the two radio frequency power supplies 4 to output a radio frequency continuous signal or a radio frequency pulse signal;

[0061] At the same time, the other of the two RF power supplies 4 is controlled to output a RF continuous signal or a RF pulse signal;

[0062] At the same time, the square wave power supply 6 is controlled to output a pulse voltage signal with a variable frequency;

[0063] The frequencies of the two radio frequency power sources 4 are different.

[0064] By combining the square wave power supply 6 with the two RF power supplies 4 and using the square wave power supply to output a pulse voltage signal with a variable frequency, the etching profile can be adjusted, thereby obtaining an etching profile with a high aspect ratio and vertical sidewalls.

[0065] In some optional embodiments, such as Figure 3 As shown, the period of the variable frequency pulse voltage signal output by the square wave power supply 6 is a first period T3, and the pulse voltage signal has a first frequency (1 / T3). The first period T3 includes a first time period t31 and a second time period t32. In the first time period t31, the pulse voltage signal has a second frequency (1 / Tm). In this case, the above-mentioned control of the square wave power supply 6 to output the variable frequency pulse voltage signal includes:

[0066] The pulse voltage signal is controlled to change from the second frequency (1 / Tm) to the first frequency (1 / T3), so that the square wave power supply 6 can output a pulse voltage signal with a variable frequency.

[0067] In summary, in the technical solutions for semiconductor process equipment and pulse signal control methods provided by embodiments of the present invention, two RF power supplies have different frequencies and are used to output either continuous RF signals or pulsed RF signals. One of the two RF power supplies is connected to the lower electrode, while the other is connected to either the lower electrode or the upper electrode. A square-wave power supply is connected to the upper electrode and is used to output a pulsed voltage signal with a variable frequency. Thus, during a plasma etching process, by combining a square-wave power supply with at least one of the two RF power supplies and utilizing the variable-frequency pulsed voltage signal outputted by the square-wave power supply, the etch profile can be adjusted, thereby achieving an etch profile with a high aspect ratio and vertical sidewalls.

[0068] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A semiconductor process equipment, characterized in that: It includes a process chamber, an upper electrode, a lower electrode, a square wave power supply and two radio frequency power supplies, wherein: The upper electrode and the lower electrode are arranged opposite to each other in the process chamber along a vertical direction, and the lower electrode is used to support the wafer; the two RF power supplies have different frequencies and are used to output RF continuous signals or RF pulse signals, one of the two RF power supplies is connected to the lower electrode, and the other is connected to the lower electrode or the upper electrode, and the square wave power supply is connected to the upper electrode to output a pulse voltage signal with a variable frequency; The period of the pulse voltage signal is the first period, which includes a first time period and a second time period. The period of the higher frequency of the two RF power supplies is the second period, and the signal output period of the second period is synchronized with the first time period.

2. The semiconductor process equipment according to claim 1, wherein: The pulse voltage signal has a first frequency, and in the first time period, the pulse voltage signal has a second frequency.

3. The semiconductor process equipment according to claim 2, wherein: The ratio of the first period to the second period is greater than or equal to 10% and less than or equal to 90%, and / or, in the first period, the duty cycle of the pulse voltage signal is greater than or equal to 10% and less than or equal to 90%.

4. The semiconductor process equipment according to claim 2, wherein: The second frequency is greater than or equal to 2 kHz and less than or equal to 400 kHz; and / or the first frequency is greater than or equal to 1 kHz and less than or equal to 50 kHz.

5. The semiconductor process equipment according to any one of claims 2 to 4, characterized in that: The two radio frequency power supplies are both connected to the lower electrode and are used to output radio frequency pulse signals; the period of the radio frequency pulse signal with a lower frequency is the third period.

6. The semiconductor process equipment according to claim 5, wherein: The signal output period in the second cycle is synchronized with the signal output period in the third cycle; or, the signal output period in the second cycle has a preset delay time relative to the signal output period in the third cycle, and the signal output period in the second cycle precedes the signal output period in the third cycle.

7. The semiconductor process equipment according to claim 6, wherein: The preset delay time is greater than or equal to half of the signal output period in the second cycle, and less than or equal to the signal output period in the second cycle.

8. The semiconductor process equipment according to claim 1, wherein: The process chamber further includes a grounded conductive component configured to contact the plasma.

9. The semiconductor process equipment according to claim 8, wherein: The conductive component includes a component constituting a chamber wall of the process chamber, or a focus ring disposed on the lower electrode. The focus ring surrounds the outer circumference of the wafer and is electrically insulated from the lower electrode.

10. The semiconductor process equipment according to claim 8 or 9, characterized in that: There are multiple square wave power supplies, one of which is connected to the upper electrode, and the remaining square wave power supplies are respectively connected to different conductive components.

11. A pulse signal control method, characterized in that: Applicable to semiconductor process equipment, the semiconductor process equipment includes a square wave power supply and two radio frequency power supplies, one of the two radio frequency power supplies is connected to the lower electrode, and the other is connected to the lower electrode or the upper electrode, and the square wave power supply is connected to the upper electrode; The pulse signal control method comprises: Controlling one of the two radio frequency power supplies to output a radio frequency continuous signal or a radio frequency pulse signal; At the same time, controlling the other of the two radio frequency power supplies to output a radio frequency continuous signal or a radio frequency pulse signal; At the same time, the square wave power supply is controlled to output a pulse voltage signal with a variable frequency; Wherein, the frequencies of the two radio frequency power supplies are different; The period of the pulse voltage signal is the first period, which includes a first time period and a second time period. The period of the higher frequency of the two RF power supplies is the second period, and the signal output period of the second period is synchronized with the first time period.

12. The pulse signal control method according to claim 11, characterized in that: The pulse voltage signal has a first frequency, and in the first time period, the pulse voltage signal has a second frequency; Controlling the square wave power supply to output a pulse voltage signal with a variable frequency includes controlling the pulse voltage signal to change from the second frequency to the first frequency.

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