Plasma system and plasma system circuit

Abstract

The utility model provides a plasma system and a plasma system circuit. The plasma system comprises a plasma processing chamber; the first power supply comprises a first output end and a second output end, the first output end is electrically connected with an electrode of the plasma processing chamber, and the second output end is connected with the chamber wall of the plasma processing chamber; a second power source including a positive output electrically connected to a substrate of the plasma processing chamber and a negative output electrically connected to a chamber wall of the plasma processing chamber; and the chamber wall of the plasma processing chamber is provided with a grounding electrode which is electrically connected with the ground. According to the scheme provided by the invention, the effect of inhibiting and treating the electric arc in the plasma process can be effectively realized.

Description

Technical Field

[0001] The invention relates to the field of plasma, and in particular to an operating method of a plasma system. Background Art

[0002] Plasma system is a common and widely used system in industrial production, for example, a system for providing power to a load or a plasma processing device.

[0003] A plasma system usually requires matching plasma equipment and plasma processes for use. This plasma process arrangement may be, for example, a plasma process chamber for industrial plasma processes, such as surface treatment of workpieces, manufacturing semiconductors with plasma, or processing workpieces with gas lasers.

[0004] In such applications, a plasma processing arrangement is used to generate a plasma.

[0005] For example, in a plasma process, target atoms are released from a target material and can then be used to coat a substrate located in a plasma process chamber.

[0006] In common plasma generation processes, a DC power supply can provide power in the form of DC pulses. These DC pulses are characterized by a high negative voltage applied for a very short time, and the DC pulses are repeated at defined time intervals. Between the DC pulses, the so-called pulse off time, the target acting as the cathode is in a floating state.

[0007] This plasma generation technique is called HiPIMS (High Power Impulse Magnetron Sputtering) and requires a suitable HiPIMS power supply.

[0008] Such HiPIMS power supplies are disclosed and described in more detail in the following publications, for example: WO 2013 / 000918 A1.

[0009] HiPIMS features include short pulses of a few microseconds or milliseconds, a short duty cycle (on / off ratio) of <10% and a high degree of ionization of the released target atoms. The average power here is very similar to conventional DC sputtering processes without pulses. The power of the pulses can be equal to or greater than 10 kW, in particular equal to or greater than 100 kW.

[0010] In addition, in this process, a bias voltage may be applied to the substrate. The bias voltage may be a voltage relative to the plasma processing chamber wall, particularly a negative voltage, and another DC power supply may be used, but pulses are not necessarily provided.

[0011] The bias voltage can be used to influence the energy and direction of motion of ionized target atoms that strike the substrate.

[0012] In a plasma system with multiple targets as cathodes, the plasma can remain active throughout the process. Coupled with the operating period of target floating, this causes charged particles of the plasma to accumulate on the target. These charged particles can change the potential of the target, thereby generating arcs. These arcs can damage the plasma process chamber itself and all objects in the plasma process chamber. Therefore, there is currently a lack of a plasma system that can suppress arc generation. Through the use of this system, arc generation can be effectively suppressed and arc treatment can be performed. Summary of the invention

[0013] The present application provides a plasma system capable of suppressing the generation of electric arcs, and provides an adapted plasma system circuit based on the operating method.

[0014] In a first aspect, the present application provides a plasma system, comprising:

[0015] a plasma processing chamber comprising a chamber wall and an electrode, the chamber wall being connected to an electrical potential, the electrical potential comprising a ground electrode;

[0016] A first power supply, the power supply is designed to provide high voltage and high power pulses;

[0017] The electrodes are connected to a first power source.

[0018] In a second aspect, the present application provides a plasma system circuit, the plasma system circuit including the above-mentioned plasma system, including:

[0019] Plasma processing chamber;

[0020] A first power supply includes a first output terminal and a second output terminal, wherein the first output terminal is electrically connected to an electrode of the plasma processing chamber, and the second output terminal is connected to a chamber wall of the plasma processing chamber;

[0021] A second power supply includes a positive output terminal and a negative output terminal, the positive output terminal is electrically connected to the substrate of the plasma processing chamber, and the negative output terminal is electrically connected to the chamber wall of the plasma processing chamber;

[0022] A grounding electrode is provided on the wall of the plasma processing chamber and is electrically connected to the earth.

[0023] In a third aspect, the present application provides a plasma system circuit, the plasma system circuit including the above-mentioned plasma system, including:

[0024] A plasma processing chamber including a plurality of electrodes and chamber walls disposed around a substrate;

[0025] A plurality of first power supplies, each of which comprises a first output terminal and a second output terminal, the first output terminal being electrically connected to an electrode of the plasma processing chamber, and the second output terminal being connected to a chamber wall of the plasma processing chamber;

[0026] a third power supply, comprising a positive output terminal and a negative output terminal, the positive output terminal being electrically connected to an electrode of the plasma processing chamber, the negative output terminal being electrically connected to a chamber wall of the plasma processing chamber, and the first power supply and the third power supply being not simultaneously connected to the same electrode;

[0027] A grounding electrode is provided on the wall of the plasma processing chamber and is electrically connected to the earth.

[0028] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0029] By using the plasma system or plasma system circuit provided in the present application to perform plasma process operations, the generation of arcs can be suppressed, thereby effectively improving the stability of the entire system and the process of outputting plasma to a load. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the first embodiment of the plasma system of the present application.

[0031] Figure 2 is the second embodiment of the plasma system of the present application,

[0032] Figure 3-7 It is a schematic diagram of voltage characteristics of the implementation process of the plasma system of the present application. DETAILED DESCRIPTION

[0033] like Figure 1 As shown, in one embodiment of the present application, a plasma system 1 is disclosed, wherein the plasma system 1 includes a plasma processing chamber 2, wherein the plasma processing chamber 2 includes a chamber wall 3, wherein an electrode 5 and a substrate 6 are arranged in the chamber wall, a gas inlet 7 and a gas outlet 8 are opened on the chamber wall, and the chamber wall 3 is electrically connected to the earth through a grounding electrode 9.

[0034] Among them, sputtering and reaction gases required for plasma generation can enter through the gas inlet 7. For example, the sputtering gas can be argon and the reaction gas can be nitrogen. The gas outlet 8 is designed to generate a vacuum in the plasma processing chamber 2. The gas outlet 8 can also have other components for generating a vacuum, such as a pump and a valve. The vacuum here means a space that is widely lacking in matter.

[0035] The plasma system 1 also includes a first power supply 4, which includes a first output terminal and a second output terminal. The first output terminal is electrically connected to the electrode 5 for outputting a first potential to the electrode, and the second output terminal is electrically connected to the chamber wall 3 for outputting a second potential to the chamber wall.

[0036] Wherein, the first power supply 4 is a power supply that can provide high voltage and high power pulses, such as a HiPIMS power supply, the voltage of the first power supply 4 is equal to or greater than 300V, preferably greater than 800V, and the pulse power of the first power supply is greater than or equal to 10kw, preferably equal to or greater than 100kw or 1000kw. The pulse duration of the first power supply is equal to or shorter than 500μs, preferably not more than 300μs, more preferably not more than 100μs, especially not longer than 20μs, especially the repetition time is 200μs to 1s, wherein the repetition time is at least 5 times the pulse duration. The HiPIMS power supply can be designed to provide pulses with an energy of at least 10J.

[0037] The electrode 5 is connected to the first output terminal of the first power source 4 so that the electrode 5 is used as the negative electrode of the first power source 4 .

[0038] The plasma system 1 further comprises a second power supply 10 , and the second power supply 10 comprises a positive output terminal and a negative output terminal.

[0039] like Figure 1 In the illustrated embodiment, the negative output terminal of the second power supply 10 is connected to the substrate 6 of the plasma processing chamber 2 , and the positive output terminal of the second power supply 10 is connected to the chamber wall 3 of the plasma processing chamber 2 .

[0040] The second power supply 10 is used to provide a bias voltage to the plasma processing chamber. The second power supply 10 may be a HiPIMS power supply or a conventional DC power supply. The bias voltage output by the second power supply 10 is a constant voltage.

[0041] If the second power source to which the substrate 6 is connected is a HiPIMS power source, the voltage applied between the substrate 6 and the chamber wall 3 is the same as the voltage applied between the electrode 5 and the chamber wall 3. However, in this application, the voltage between the substrate 6 and the chamber wall 3 is not used for the generation of plasma, but is used as a bias voltage.

[0042] The substrate can be connected to the HiPIMS power supply and the second power supply 10 at the same time. If the HiPIMS power supply and the second power supply 10 are connected to the substrate, a switch can be used to adjust the on-off state, for example, the HiPIMS power supply or the second power supply 10 can be turned on and off by the switch. This allows the voltage provided by the HiPIMS power supply (first power supply 4) or the second power supply to be turned on and off. For example, the switch can be a semiconductor switching element, such as a metal oxide semiconductor field effect transistor (MOSFET).

[0043] If only the second power supply 10 is connected to the substrate 6 , the bias voltage can be provided to the plasma system through the second power supply 10 .

[0044] Through the above technical solution, the plasma system provided in the present application can effectively avoid the generation of arcs or suppress the generation of arcs on the basis of completing the basic function of plasma generation, thereby providing a more stable plasma process environment.

[0045] When operating the plasma system 1 described above, the following method is used:

[0046] In the first potential supply step, a first potential is provided to the electrode 5 of the plasma processing chamber 2 through the first power supply 4, wherein the first potential is a high voltage pulse of a negative potential, wherein the conduction duration of the first potential is set to t on ;

[0047] The first potential interruption step is to stop supplying the first potential through the first power supply 4, wherein the shutdown duration of the first potential is set to t off ;

[0048] A second potential supplying step, providing a second potential to the chamber wall 3 of the plasma processing chamber 2 by the first power supply 4 before providing the first potential, wherein the second potential is a positive potential;

[0049] The high voltage pulse of the first potential is a pulse with a negative potential, and its pulse conduction duration t on Preferably shorter than the closing duration t off In particular, the pulse on-time t on At most the pulse off duration t off One-third of f, f=5, particularly 10, preferably 20, wherein the larger f is, the better the arc suppression / extinguishing effect is achieved.

[0050] In operation, it is important that the electrode is connected to the second potential immediately before the high voltage pulse and the first potential is started. "Immediately" means that the duration between the end of the second potential and the start of the pulse with the first potential is predefined and needs to be as short as technically possible. It is obvious that the first potential has high energy and may damage the power supply module corresponding to the second potential, so before the start of the pulse with the first potential, the power supply providing the second potential must be disconnected or at least protected. On the other hand, the duration between the end of the second potential and the start of the pulse with the first potential should not be so long that the particles on the electrode 5 are charged again. Therefore, since this also depends on the geometry of the plasma processing chamber 2 and the configuration of the electrode 5, a duration of ≤1ms, especially 100μs≤ is more effective.

[0051] Furthermore, during operation of the plasma system, the electrodes of the plasma system may be closed for the entire shutdown duration t off Connect to a positive potential relative to the plasma process chamber.

[0052] The positive potential of the connection can be a constant potential (provided by the second power supply 10). off The positive potential does not allow positively charged particles to accumulate on the electrode, thereby preventing arcing when a HiPIMS pulse with a negative potential (provided by the first power supply 4) starts.

[0053] The positive potential can also be connected in short pulses (provided by the first power supply 4). These pulses with positive potential can have a ramp pattern, such as a linear slope or a step shape. In addition, these pulses can have different lengths. A pulse with positive potential immediately before a HiPIMS pulse with negative potential (provided by the first power supply 4) can remove positively charged particles from the electrode, thereby preventing arcing at the beginning of the HiPIMS pulse with negative potential.

[0054] In such Figure 1 In the embodiment shown, the electrode 5 is used as a target material for the cathode, and the target material has the characteristics of low conductivity, preferably a non-conductive material. When operating the plasma system 1, a low-conductive or particularly non-conductive target is used. Here, low conductivity means that the target is a target with high resistance per area, for example, a resistance ≥ 100Ω / cm 2 .

[0055] In addition, in the method of operating the plasma system, the electrode 5 of the plasma system is used as a target as a cathode of the HiPIMS power supply. The electrode 5 can be a solid object suitable for use as an electrode and also contains the material of the substrate to be coated. The structural integration of the target and the electrode 5 makes the structure of the plasma system 1 simple.

[0056] like Figure 2 As shown, a second embodiment of the present application discloses a plasma system 1, including a plasma processing chamber 2, a chamber wall 3 of the plasma processing chamber 2, and a gas inlet (not shown) and a gas outlet (not shown) are provided on the chamber wall 3.

[0057] The second embodiment of the present application is different from the first embodiment (such as Figure 1The difference between the plasma processing chamber 2 and the plasma processing chamber 2 is that a substrate 6 is arranged in the plasma processing chamber 2. The substrate 6 is constructed as a tool holder rotatable in multiple directions, wherein the tool will be covered by the plasma process. This plasma processing chamber is provided with four electrodes 5a, 5b, 5c, 5d around the substrate 6, and the plasma system is provided with a first power supply 4a and a first power supply 4b at positions close to the electrode 5a and the electrode 5c, respectively. The first output end of the first power supply 4a is electrically connected to the electrode 5a, and the second output end of the first power supply 4b is electrically connected to the chamber wall 3. The first output end of the first power supply 4b is electrically connected to the electrode 5c, and the second output end of the first power supply 4b is electrically connected to the chamber wall 3.

[0058] In this embodiment, the plasma system 1 has multiple electrodes 5a-5d. This makes the wear resistance of the coated substrate higher than that of a single electrode plasma system (such as Figure 1 A coated substrate in a plasma system (shown).

[0059] A third power supply 10b is arranged near the electrode 5b of the plasma processing chamber 2, the negative output end of the third power supply 10b is connected to the electrode 5b of the plasma processing chamber 2, and the positive output end of the third power supply 10b is connected to the chamber wall 3 of the plasma processing chamber 2.

[0060] The chamber wall 3 is electrically connected to the ground via a grounding electrode 9 .

[0061] This embodiment and Figure 1 The difference from the first embodiment shown is that there are multiple electrodes 5a-5d in the plasma system 1 of this embodiment, and a power supply is connected to each electrode. Matching this, the substrate 6 in this embodiment is set differently from that in the first embodiment. Through the above-mentioned difference technical features, the wear resistance of the coating substrate of the entire plasma processing chamber can be stronger than that of the same type of single-electrode products, thereby improving the stability and service life of the plasma system.

[0062] like Figure 2 As shown in the second embodiment of the present application, the first magnet 11 and the second magnet 12 are arranged at positions close to any of the electrodes 5a, 5b, 5c, and 5d of the plasma processing chamber 2, wherein the first magnet 11 is arranged at both ends of the length direction of the second magnet 12. The magnetic poles of the first magnet 11 and the second magnet 12 are arranged as follows: Figure 2 The magnetic field created by these magnets is used to enhance the ionization process.

[0063] like Figure 2 In the illustrated plasma processing chamber 2, the electrode 5d may also be connected to a power supply (not shown), which may be of a different type than the HIPIMS power supply.

[0064] In one aspect, the method includes the step of supplying power to a second electrode in the plasma chamber via a power source (third power source 10b) different from the HIPIMS power source.

[0065] By "different" here we mean that the power supply is not of the same type, so it does not provide HIPIMS pulses. It can be a pulsed DC power supply, providing low energy pulses to the second electrode. It can be a DC power supply, providing continuous DC power to the second electrode. It can be an IF power supply, providing bipolar rectangular or bipolar wave IF power to the second electrode, e.g. in the frequency range of 1 kHz to 500 kHz. It can be an HF power supply, providing high frequency power to the second electrode, e.g. in the frequency range of 1 MHz to 200 MHz.

[0066] like Figure 3-7 As shown, in one embodiment of the present application, a plasma system (including Figure 1 and Figure 2 The operating method of the plasma system shown in the figure) comprises:

[0067] In the first potential supply step, a first potential is provided to the plasma processing chamber 2 through the HiPIMS power supply, wherein the first potential is a high voltage pulse of a negative potential, wherein the conduction duration of the first potential is set to t on ;

[0068] The first potential interruption step is to stop supplying the first potential through the HiPIMS power supply, wherein the shutdown duration of the first potential is set to t off ;

[0069] a second potential supplying step, providing a second potential to the plasma processing chamber (2) by means of the HiPIMS power supply before providing the first potential, wherein the second potential is a positive potential;

[0070] The first potential is provided to the electrode 5 of the plasma processing chamber 2 , and the second potential is provided to the chamber wall 3 of the plasma processing chamber 2 .

[0071] The method can prevent or at least mitigate the accumulation of charged particles on a target of a plasma system. Thus, destructive arcing can be mitigated.

[0072] As long as any plasma system has a suitable HiPIMS power supply, the operating method of the plasma system disclosed in the embodiments of the present application can be used, which makes the operating method of the plasma system according to the present invention very widely applicable.

[0073] Figures 3 to 7 The figure shows possible voltage characteristics of negative voltages according to the plasma system operation method according to the present invention, wherein voltage U is shown over time t. Here, "negative voltage" refers to the HiPIMS power supply (e.g. Figure 1 and Figure 2 The pulses are provided by the first power supply 4, 4a, 4b) shown in FIG. The characteristic short pulses of the first potential, in particular the characteristics of a high negative voltage here, have the same pulse conduction duration t in all figures. on During the off time t off After that, the next pulse with a high negative voltage (first potential) starts. Therefore, these high voltage pulses with the first potential have a repetition time, that is, the pulse conduction duration t on and closing duration t off The sum of the second potential, in particular the positive voltage pulse of the present invention, is closed for a duration t off During the period from Figures 3 to 6 are different.

[0074] During the characteristic short negative pulse, the HiPIMS power supply provides a negative voltage U low This pulse starts from t1, t3, t5 and ends at t2, t4, t6, and lasts for t on After the pulses at t2, t4, and t6 are completed, the pulse off duration t off The HiPIMS power supply is usually implemented by one or more energy storage devices (e.g. one or more large capacitors) which are connected to the HiPIMS power supply during the pulse off duration t off During the period, the load is at a high energy level, such as a high voltage, and the pulse is on for a duration of t on Therefore, during the pulse off duration t off In the embodiment of the present invention, the electrode 5 is not connected to any potential and is therefore floating. It is found that such a floating electrode 5 tends to attract particles, ions and / or atoms present in the plasma chamber. These particles, ions and / or atoms may cause poor insulation or at least poor conductive surfaces on or near the electrode. It is further found that such a surface may be charged with the start of one of the following pulses, or even charged by other similar continuous plasma processes in the chamber. Such charging may result in higher arc rates, which can be avoided in the effect of the present application scheme.

[0075] During the pulse off duration t off The HiPIMS power supply of the present invention can provide pulses of a second potential opposite to the first potential, particularly in the form of positive and negative voltages. The pulses with the second potential may be different in shape and length and can prevent charged particles from accumulating on the target, thereby mitigating arcing.

[0076] It is important that the pulse with the first potential is immediately preceded by the pulse with the second potential, which is opposite to the first potential. "Immediately" means that the duration between the end of the second potential and the start of the pulse with the first potential is predefined in a way that is as short as technically possible. As before, it is obvious that the first potential has a high energy and can damage the power supply providing the second potential. Therefore, before the start of the pulse with the first potential, the power supply providing the second potential must be disconnected or at least protected. This takes at least some time. On the other hand, the duration between the end of the second potential and the start of the pulse with the first potential should not be so long that the particles on the electrode 5 are charged again. Therefore, since this also depends on the geometry of the plasma chamber 2 and the electrode 5, a duration of ≤1 ms, in particular ≤100 μs, is reasonable.

[0077] from Figures 3 to 6 It can be seen that the high voltage pulse with the first potential, especially the pulse with the negative potential, may preferably have a pulse on duration t relative to the plasma processing chamber. on , which is much shorter than the pulse off duration t off In particular, the pulse on-time is at most the off-time t off f=5, especially 10, preferably 20. The larger f is, the better the arc suppression / extinguishing effect is.

[0078] exist Figure 3 The positive pulse has t high The HiPIMS power supply provides a high negative voltage U throughout the pulse. high The positive pulse is applied immediately before the pulse with the high negative voltage.

[0079] exist Figure 4 The HiPIMS power supply is turned off for a duration of t off Provide voltage U high .

[0080] exist Figure 5 The positive pulse has a ramp mode and t high Length. The positive pulse is at the pulse off duration t off Before the negative pulse at the end. The positive pulse increases linearly to voltage U high When the voltage U high After that, it remains constant until the pulse is turned off for duration t off Finish.

[0081] Figure 6 and Figure 5 Very similar, except that here the positive pulse is from the negative voltage U high Initially, it remains constant for a predetermined time, and then decreases linearly until the closing duration toff The end of.

[0082] Figure 7 and Figure 5 Very similar, except that the positive pulse here does not rise linearly, but rises in steps.

[0083] In addition to the pulse shapes shown, other pulse shapes or combinations of pulse shapes may be used for the negative voltage.

Claims

1. A plasma system, characterized in that: The plasma system (1) comprises: A plasma processing chamber (2), the plasma processing chamber comprising a chamber wall (3) and an electrode (5), the chamber wall (3) being connected to an electrical potential, the electrical potential comprising a ground electrode (9); A first power source (4), the power source being configured to provide high voltage and high power pulses; The electrode (5) is connected to a first power source (4).

2. The plasma system according to claim 1, characterized in that: The first power source (4) comprises a first output end and a second output end, the first output end is electrically connected to the electrode (5), and the second output end is connected to the chamber wall (3).

3. The plasma system according to claim 1 or 2, characterized in that: The chamber wall (3) is provided with a gas inlet (7) and a gas outlet (8).

4. The plasma system according to claim 3, characterized in that: The plasma processing chamber further comprises a substrate (6), the substrate (6) being electrically connected to a negative output terminal of a second power source (10), and a positive output terminal of the second power source (10) being electrically connected to the chamber wall (3).

5. The plasma system according to claim 3, characterized in that: The plasma processing chamber (2) comprises a plurality of electrodes (5), each of which is a magnetic electrode. The plasma processing chamber (2) further comprises a substrate (6), and a plurality of electrodes (5) are arranged around the substrate (6).

6. The plasma system according to claim 5, characterized in that: At least one of the electrodes (5) is electrically connected to a first power source (4), and at least one of the electrodes (5) is connected to a third power source (10b).

7. The plasma system according to claim 5 or 6, characterized in that: The plasma processing chamber (2) is provided with a first magnet (11) and / or a second magnet (12) at a position close to the electrode (5).

8. The plasma system according to claim 7, characterized in that: The plasma processing chamber (2) has four electrodes (5), and first power supplies (4) are respectively arranged on two opposite sides of the plasma system, a first output end of the first power supply (4) is electrically connected to the electrode (5), and a second output end of the first power supply (4) is connected to the chamber wall (3); A second power supply (10) is provided on one side of the plasma processing chamber (2), the positive output end of the second power supply (10) is connected to the chamber wall (3), and the negative output end of the second power supply (10) is connected to the electrode (5) adjacent thereto.

9. A plasma system circuit, characterized in that: The plasma system circuit comprises a plasma system (1) according to any one of claims 1 to 8, wherein the plasma system circuit comprises: A plasma processing chamber (2); A first power supply (4) comprising a first output end and a second output end, wherein the first output end is electrically connected to an electrode (5) of the plasma processing chamber (2), and the second output end is electrically connected to a chamber wall (3) of the plasma processing chamber; A second power supply (10) comprises a positive output terminal and a negative output terminal, wherein the positive output terminal is electrically connected to a substrate (6) of the plasma processing chamber (2), and the negative output terminal is electrically connected to a chamber wall (3) of the plasma processing chamber (2); The chamber wall (3) of the plasma processing chamber (2) is provided with a grounding electrode (9) which is electrically connected to the earth.

10. A plasma system circuit, characterized in that: The plasma system circuit comprises a plasma system (1) according to any one of claims 1 to 8, wherein the plasma system circuit comprises: A plasma processing chamber (2), a plurality of electrodes (5) and a chamber wall (3); A plurality of first power supplies (4), each of the first power supplies comprising a first output end and a second output end, the first output end being electrically connected to an electrode (5) of the plasma processing chamber (2), and the second output end being electrically connected to a chamber wall (3) of the plasma processing chamber; a third power supply (10b), comprising a positive output terminal and a negative output terminal, the positive output terminal being electrically connected to an electrode (5) of the plasma processing chamber (2), the negative output terminal being electrically connected to a chamber wall (3) of the plasma processing chamber (2), the first power supply (4) and the third power supply (10b) being not electrically connected to the same electrode (5) at the same time; The chamber wall (3) of the plasma processing chamber (2) is provided with a grounding electrode (9) which is electrically connected to the earth.

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