Plasma Processing Apparatus and Plasma Processing Method

Abstract

The present invention provides a plasma processing apparatus and a plasma processing method capable of improving plasma ignition performance without using rare gases. The plasma processing apparatus includes: a processing container; a mounting table; a metal window that forms the top of the processing container while being electrically insulated from the processing container and is grounded; an inductively coupled antenna disposed opposite the mounting table with the metal window therebetween and configured while being electrically insulated from the metal window; and a control unit for controlling plasma processing. The control unit can execute: a first control of supplying a first high frequency to the mounting table at a first electric power and igniting plasma by capacitive coupling between the metal window and the mounting table; a second control of supplying a second high frequency to the inductively coupled antenna at a second electric power and maintaining the plasma by inductive coupling via the metal window; and a third control of changing the electric power of the first high frequency to a third electric power greater than the first electric power and performing plasma processing on a substrate placed on the mounting table.

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus and a plasma processing method. Background Art

[0002] There is known a plasma processing apparatus that uses inductively coupled plasma to process a substrate (for example, see Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-17646 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] The present invention provides a technique for improving plasma ignition performance without using a rare gas.

[0008] Means for Solving the Technical Problem

[0009] A plasma processing apparatus according to one aspect of the present invention includes: a processing container configured to perform plasma processing on a substrate using plasma inside the processing container; a mounting table disposed inside the processing container, which is capable of mounting the substrate and also serves as a lower electrode; a metal window that forms the top of the processing container while being electrically insulated from the processing container and is grounded; an inductively coupled antenna disposed opposite to the mounting table with the metal window therebetween and is electrically insulated from the metal window; and a control unit for controlling the plasma processing, the control unit being capable of executing: a first control of supplying a first high frequency to the mounting table at a first electric power to ignite the plasma by capacitive coupling between the metal window and the mounting table; a second control of supplying a second high frequency to the inductively coupled antenna at a second electric power to maintain the plasma by inductive coupling via the metal window; and a third control of changing the electric power of the first high frequency to a third electric power greater than the first electric power to perform the plasma processing on the substrate mounted on the mounting table.

[0010] Advantageous Effects of the Invention

[0011] By adopting the present invention, it is possible to improve plasma ignition performance without using a rare gas. Brief Description of the Drawings

[0012] Figure 1 It is a schematic diagram showing a plasma processing apparatus according to an embodiment.

[0013] Figure 2 It is a diagram showing a plasma processing method according to an embodiment.

[0014] Figure 3 These are diagrams showing modified examples of the embodiment method of the plasma processing method.

[0015] Figure 4 These are diagrams showing Figure 2 the plasma ignition property when the plasma processing method shown is performed.

[0016] Figure 5 These are diagrams showing Figure 3 the plasma ignition property when the plasma processing method shown is performed.

[0017] Figure 6 These are diagrams (1) showing the plasma ignition property when the offset time is changed.

[0018] Figure 7 These are diagrams (2) showing the plasma ignition property when the offset time is changed.

[0019] Figure 8 These are diagrams (3) showing the plasma ignition property when the offset time is changed.

[0020] Figure 9 These are diagrams (1) showing the plasma ignition property when the processing gas is changed.

[0021] Figure 10 These are diagrams (2) showing the plasma ignition property when the processing gas is changed.

[0022] Figure 11 These are diagrams (3) showing the plasma ignition property when the processing gas is changed.

[0023] Figure 12 These are diagrams showing the plasma ignition property when multi-step processing is performed.

[0024] Figure 13 These are diagrams showing the erosion amount of the target film when processing based on the first control is performed.

[0025] Explanation of Reference Numerals

[0026] 1 Processing container, 2 Metal window, 3 Mounting table, 9 Control unit, G Substrate. Detailed Embodiment

[0027] Hereinafter, a non-limiting exemplary embodiment of the present invention will be described with reference to the drawings. In all the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and repeated explanations are omitted.

[0028] (Plasma Processing Apparatus)

[0029] Reference Figure 1 , a plasma processing apparatus according to an embodiment will be described. The plasma processing apparatus includes a processing container 1 , a metal window 2 , a mounting table 3 , a plasma generating unit 7 , and a control unit 9 .

[0030] The processing container 1 is a vacuum container whose interior can be decompressed. A mounting table 3 is accommodated in the processing container 1. The processing container 1 is formed of a metal material such as aluminum or stainless steel. The processing container 1 is grounded.

[0031] A delivery port 11 is provided on the side of the processing container 1. The delivery port 11 is an opening for delivering a substrate G to be processed by plasma. A gate valve 12 is provided on the delivery port 11. The gate valve 12 can open and close the delivery port 11. The substrate G is, for example, a rectangular glass substrate.

[0032] An exhaust port 13 is provided on the bottom surface of the processing container 1. The exhaust port 13 may be Figure 1 The exhaust unit 15 is connected to the exhaust port 13 via the exhaust pipe 14. The exhaust unit 15 can adjust the pressure in the processing container 1. The exhaust unit 15 includes a vacuum pump and a pressure regulating valve (neither of which are shown).

[0033] The metal window 2 seals the upper part of the processing container 1 via an insulating component 16, and is suspended from the top of an antenna room (not shown) disposed adjacent to the upper part of the processing container 1. The metal window 2 forms the top of the processing container 1 while being electrically insulated from the processing container 1. The metal window 2 functions as a shower head for supplying a processing gas into the processing container 1. The metal window 2 is formed by a plurality of split windows 2a. The plurality of split windows 2a are electrically insulated from each other via an insulating component 2b. For example, the plurality of split windows 2a are arranged radially when viewed from above. Alternatively, the plurality of split windows 2a may be arranged in a lattice when viewed from above. The arrangement of the plurality of split windows 2a is not limited to these. The number of split windows 2a is not particularly limited, and may be, for example, 20. In addition, the metal window 2 may be formed by a single component.

[0034] Each partition window 2a has a gas dispersion chamber 20 and a gas supply hole 21. The gas dispersion chamber 20 is formed inside each partition window 2a. A plurality of gas supply holes 21 are formed on the lower surface of each partition window 2a in a manner opposite to the upper surface of the mounting table 3. The gas supply hole 21 is connected to the gas dispersion chamber 20. A gas supply source 23 is connected to each gas dispersion chamber 20 via a gas supply pipe 22. The gas supply source 23 is a supply source of a processing gas. The type of processing gas is not limited, and for example, it can be carbon tetrafluoride (CF 4 ), oxygen (O 2)、 Argon (Ar). On the gas supply pipe 22, a flow rate adjusting section 24 and a valve 25 are provided in sequence from the gas supply source 23 side. The processed gas with the adjusted flow rate can be supplied to each gas dispersion chamber 20 via the gas supply pipe 22.

[0035] Each divided window 2a is grounded via an impedance adjusting circuit 26. The impedance adjusting circuit 26 can adjust the impedance between each divided window 2a and the ground. In addition, each divided window 2a may be grounded without passing through the impedance adjusting circuit 26.

[0036] The mounting table 3 has a prismatic shape with a rectangular planar shape. A substrate G can be mounted on the mounting table 3. The mounting table 3 is configured such that a spacer 35 and a base 33 are stacked in sequence from below, and the side surfaces of the spacer 35 and the base 33 are covered by a ceramic cover 38, for example. The mounting table 3 is provided at the central portion of the bottom surface of the processing container 1 with an insulating layer 39 interposed therebetween.

[0037] A heat transfer gas supply path 34 is provided inside the mounting table 3. The downstream end portion of the heat transfer gas supply path 34 branches into a plurality of paths and opens dispersedly on the upper surface of the mounting table 3, thereby forming a plurality of heat transfer gas supply ports 34a. The upstream side of the heat transfer gas supply path 34 is connected to a heat transfer gas supply pipe 62 provided outside the processing container 1. The upstream side of the heat transfer gas supply pipe 62 is connected to a heat transfer gas supply source 64 via a flow rate adjusting section 63. The plurality of heat transfer gas supply ports 34a can supply heat transfer gas to the minute gap between the lower surface of the substrate G mounted on the upper surface of the mounting table 3 and the upper surface of the mounting table 3.

[0038] Inside the spacer 35, a ring-shaped refrigerant flow path 36 extending in the circumferential direction, for example, is provided. A refrigerant adjusted to a prescribed temperature by a cooling unit (not shown) can be circulated and supplied to the refrigerant flow path 36. By controlling the temperature of the refrigerant, the temperature of the substrate G can be adjusted by the heat transfer gas between the base 33 and the lower surface of the substrate G.

[0039] In the mounting table 3, a lifting pin (not shown) for exchanging the substrate G with an external transfer device (not shown) is provided. The lifting pin can penetrate vertically through the mounting table 3 and the bottom plate of the processing container 1 and project and retract relative to the surface of the mounting table 3.

[0040] A dielectric layer 31 is provided on the upper surface of the base 33. An adsorption electrode 32 made of metal and extending in the horizontal direction is buried in the dielectric layer 31. The dielectric layer 31 and the adsorption electrode 32 constitute an electrostatic chuck. The adsorption electrode 32 is connected to a DC power supply 40 via a wiring 41. The DC power supply 40 can apply a DC voltage (adsorption voltage) to the adsorption electrode 32 based on, for example, a set value input from the control unit 9. When the adsorption voltage is applied to the adsorption electrode 32, an electrostatic attraction can be generated between the adsorption electrode 32 and the substrate G across the dielectric layer 31. Thus, the substrate G can be adsorbed and held on the dielectric layer 31. A resistor 42 and a switch 43 for adjusting the adsorption voltage are provided on the wiring 41.

[0041] The plasma generation unit 7 has an inductively coupled antenna 70. The inductively coupled antenna 70 is disposed above the processing container 1 so as to face the stage 3 with the metal window 2 therebetween. The inductively coupled antenna 70 has a spiral or ring shape. The inductively coupled antenna 70 is housed in an antenna chamber (not shown) provided above the metal window 2. The source power supply 72 is connected to the inductively coupled antenna 70 via a matcher 71. The matcher 71 includes a variable capacitor. The source power supply 72 can supply a source RF signal (second high frequency) to the inductively coupled antenna 70. Thus, an electric field for maintaining the plasma generation state can be generated in the processing container 1. The source RF signal has a frequency of, for example, 13.56 MHz.

[0042] The plasma generation unit 7 further has a bias power supply 75. The bias power supply 75 is connected to the base 33 via a wiring 73. The bias power supply 75 can supply a bias RF signal (first high frequency) to the base 33. Thus, in the present embodiment, plasma generation (plasma ignition) can be started by capacitive coupling between the metal window 2 and the stage 3. In this way, the metal window 2 and the stage 3 respectively function as the upper electrode and the lower electrode in capacitive coupling at the moment of plasma ignition. In addition, ions and the like contained in the plasma of the processing gas whose generation state is maintained in the processing container 1 by the supply of the source RF signal can be directed to the substrate G placed on the stage 3. A matcher 74 for obtaining matching of the bias RF signal is provided on the wiring 73. The matcher 74 includes a variable capacitor. The bias RF signal has a frequency of, for example, 3.2 MHz. In addition, generally, a circuit including a bias power supply and the like is for directing ions from the generated plasma to the substrate, and thus is not included in the "plasma generation unit". However, in the present embodiment, the circuit including the bias power supply and the like has a function of igniting the plasma, and thus is specifically described as a component constituting a part of the "plasma generation unit".

[0043] The control unit 9 can control each part of the plasma processing apparatus. The control unit 9 includes, for example, a computer 90. The computer 90 includes a CPU 91, a storage unit 92, and a communication interface 93. The CPU 91 can perform various control operations based on programs stored in the storage unit 92. The storage unit 92 includes at least one memory type selected from auxiliary storage devices such as RAM, ROM, HDD (Hard Disk Drive), and SSD (Solid State Drive). The storage unit 92 can store various information used when implementing the plasma processing method described later. The various information includes, for example, set values such as adsorption voltage, electric power of the source RF signal, electric power of the bias RF signal, and flow rate of the processing gas. The various information includes, for example, preset positions of the variable capacitors of the matchers 71 and 74. The communication interface 93 can communicate with the plasma processing apparatus via a communication line such as a LAN (Local Area Network).

[0044] (Plasma Processing Method)

[0045] Refer to Figure 2 , to take the case where plasma processing is performed on the substrate G placed on the stage 3 in the plasma processing apparatus shown in Figure 1 as an example, the plasma processing method of the embodiment will be described.

[0046] First, at time t11, the control unit 9 applies an adsorption voltage from the DC power supply 40 to the adsorption electrode 32 by controlling the switch 43 to be turned on. In addition, at time t11, the control unit 9 supplies the processed gas with the adjusted flow rate from the gas supply source 23 to each gas dispersion chamber 20 by opening the valve 25 and controlling the flow rate adjustment unit 24. In addition, at time t11, the control unit 9 adjusts the pressure in the processing container 1 from the pre-processing pressure P1 to the ignition pressure P3 by controlling the exhaust unit 15. The pre-processing pressure P1 can be the pressure in the state after being evacuated by the exhaust unit 15. For example, it is a pressure of 1 mTorr (0.13 Pa) or less. The pre-processing pressure P1 can also be a specified pressure adjusted by the exhaust unit 15. The ignition pressure P3 is a pressure higher than the pre-processing pressure P1 and can be a specified pressure adjusted by the exhaust unit 15. From the viewpoint of easily achieving stable plasma ignition regardless of the type of processing gas, the ignition pressure P3 is preferably 15 mTorr to 25 mTorr (2.0 Pa to 3.3 Pa), and more preferably 20 mTorr (2.7 Pa).

[0047] Next, at time t12, the control unit 9 executes first control to supply a bias RF signal to the susceptor 33 at a first bias electric power Pb1 by controlling the bias power supply 75, and starts plasma generation (plasma ignition) by capacitive coupling between the metal window 2 and the susceptor 3. In the first control, it is preferable that the control unit 9 supplies a bias RF signal to the susceptor 33 in a state where the position of the variable capacitor of the matcher 74 is moved to a preset position for plasma ignition of the bias power supply 75 stored in the storage unit 92. Thereby, the plasma ignition time can be shortened. The preset position for plasma ignition of the bias power supply 75 can be determined by preliminary experiments or the like and stored in the storage unit 92 in advance.

[0048] Next, at time t13, the control unit 9 adjusts the pressure in the processing chamber 1 from the ignition pressure P3 to the processing pressure P2 by controlling the exhaust unit 15. The processing pressure P2 may be a pressure lower than the ignition pressure P3. For example, the processing pressure P2 may be 5 mTorr to 15 mTorr (0.67 Pa to 2.0 Pa).

[0049] Next, at time t14, the control unit 9 executes second control to supply a source RF signal to the inductively coupled antenna 70 at a first source electric power Ps1 by controlling the source power supply 72, and maintains the plasma generation state by inductive coupling via the metal window 2. At time t14, a source RF signal is supplied to the inductively coupled antenna 70 in a state where the pressure in the processing chamber 1 is maintained at the processing pressure P2.

[0050] Next, at time t15, the control unit 9 executes third control to change the electric power of the bias RF signal from the first bias electric power Pb1 to the second bias electric power Pb2 and perform plasma processing on the substrate G placed on the susceptor 3. The second bias electric power Pb2 is a value higher than the first bias electric power Pb1. However, depending on the type of plasma processing performed on the substrate G, the second bias electric power Pb2 may also be a value lower than the first bias electric power Pb1. Time t15 is preferably performed after a preset time (hereinafter referred to as "bias time") has elapsed from the time (time t14) when the source RF signal is supplied to the inductively coupled antenna 70. Thereby, the bias RF signal is likely to stabilize at the second bias electric power Pb2. The bias time is preferably 2 seconds or more.

[0051] After the plasma treatment performed on the substrate G ends after a predetermined time has elapsed since time t15, the control unit 9 stops supplying the source RF signal to the metal window 2 by controlling the source power supply 72, and stops supplying the bias RF signal to the susceptor 33 by controlling the bias power supply 75. Further, the control unit 9 stops supplying the processing gas to each gas dispersion chamber 20 by closing the valve 25, and decompresses the inside of the processing chamber 1 by controlling the exhaust unit 15. After that, the control unit 9 ends the processing.

[0052] Conventionally, in a case where plasma ignition is difficult, there is a method of introducing a noble gas in which plasma is easily ignited to ignite the plasma. However, depending on the device formed on the substrate G, there are adverse effects such as deterioration of electrical characteristics. With the plasma processing method of the embodiment described above, the control unit 9 supplies the bias RF signal to the susceptor 33 in a state where the processing gas is supplied into the processing chamber 1, and ignites the plasma by capacitive coupling between the metal window 2 and the stage 3. Then, the control unit 9 supplies the source RF signal to the inductive coupling antenna 70 and maintains the plasma by inductive coupling via the metal window 2. Thus, it is possible to improve the plasma ignition property without using a gas other than the processing gas (for example, a noble gas). Therefore, the substrate G is not exposed to plasma generated from a gas other than the processing gas. As a result, it is possible to reduce the influence on the electrical characteristics of the device formed on the substrate G.

[0053] Further, in the plasma processing method of the embodiment, the control unit 9 may store log information for determining whether the plasma has been ignited by capacitive coupling when the first control is executed in the storage unit 92. Thus, a manager or the like can determine whether the plasma has been ignited by capacitive coupling when the first control is executed by confirming the log information stored in the storage unit 92. The log information may include, for example, measured values indicating the state of the bias RF signal before the start of the first control, during the execution of the first control, and immediately after the end of the first control. Examples of the measured value indicating the state of the bias RF signal include the forward wave electric power of the bias RF signal, the reflected wave electric power, the difference Vpp (Voltage peak to peak) between the maximum voltage and the minimum voltage of the bias RF signal, and the intermediate voltage Vdc (Voltage direct current) of the bias RF signal. Further, the log information may include setting values related to the first control, such as the setting value of the electric power of the bias RF signal and the setting value of the execution time of the first control.

[0054] In addition, in a multi-step process including multiple discharge steps for performing plasma processing on the substrate G placed on the stage 3, it is sufficient to perform the plasma processing method of the embodiment at least for the first discharge step. That is, at least in the first discharge step, plasma is ignited by capacitive coupling between the metal window 2 and the stage 3, and then the plasma is maintained by inductive coupling via the metal window 2. This is because, in a multi-step process, when plasma ignition can be performed in the first discharge step, plasma ignition can also be stably performed in the second and subsequent discharge steps. In addition, in a multi-step process, there may be a case where it starts from the middle (e.g., the second) discharge step among multiple discharge steps. In this case, it is sufficient to perform the plasma processing method of the embodiment at least for the just-started (e.g., the second) discharge step.

[0055] Refer to Figure 3 , in order to Figure 1 Take the case of performing plasma processing on the substrate G placed on the stage 3 in the plasma processing apparatus shown as an example, and the plasma processing method of the modified example of the embodiment will be described. The difference between the plasma processing method of the modified example of the embodiment and the Figure 2 plasma processing method of the embodiment shown is that after supplying the source RF signal to the inductive coupling antenna 70, the pressure in the processing chamber 1 is adjusted from the ignition pressure P3 to the processing pressure P2. Hereinafter, the description will be centered on the differences from the Figure 2 plasma processing method of the embodiment shown.

[0056] First, at time t21, the control unit 9 controls the switch 43 to be turned on to apply an adsorption voltage from the DC power supply 40 to the adsorption electrode 32. In addition, at time t21, the control unit 9 opens the valve 25 and controls the flow rate adjustment unit 24 to supply the processed gas with the adjusted flow rate from the gas supply source 23 to each gas dispersion chamber 20. In addition, at time t21, the control unit 9 controls the exhaust unit 15 to adjust the pressure in the processing chamber 1 from the pre-processing pressure P1 to the ignition pressure P3.

[0057] Next, at time t22, the control unit 9 controls the bias power supply 75 to execute the first control of supplying a bias RF signal to the susceptor 33 with the first bias electric power Pb1 and igniting plasma by capacitive coupling between the metal window 2 and the stage 3.

[0058] Next, at time t23, the control unit 9 controls the source power supply 72 to execute second control for supplying a source RF signal to the inductively coupled antenna 70 at a first source electric power Ps1 and maintaining the plasma by inductive coupling through the metal window 2. At time t23, the source RF signal is supplied to the inductively coupled antenna 70 while the pressure in the processing chamber 1 is maintained at the ignition pressure P3.

[0059] Next, at time t24, the control unit 9 controls the bias power supply 75 to execute third control for changing the electric power of the bias RF signal from a first bias electric power Pb1 to a second bias electric power Pb2 and performing plasma processing on the substrate G placed on the stage 3.

[0060] Next, at time t25, the control unit 9 controls the exhaust unit 15 to adjust the pressure in the processing chamber 1 from the ignition pressure P3 to a processing pressure P2. The processing pressure P2 may be a pressure lower than the ignition pressure P3.

[0061] After a predetermined time has elapsed since time t25 and the plasma processing of the substrate G has ended, the control unit 9 controls the source power supply 72 to stop supplying the source RF signal to the metal window 2, controls the bias power supply 75 to stop supplying the bias RF signal to the susceptor 33, closes the valve 25 to stop supplying the processing gas to each gas dispersion chamber 20, and controls the exhaust unit 15 to decompress the inside of the processing chamber 1. After that, the control unit 9 ends the processing.

[0062] With the plasma processing method according to the modification of the above-described embodiment, it is possible to improve the plasma ignition property without using a gas other than the processing gas (e.g., noble gas), Figure 2 similarly to the plasma processing method of the embodiment shown.

[0063] In addition, in the plasma processing method according to the modification of the embodiment, the case where the pressure in the processing chamber 1 is adjusted from the ignition pressure P3 to the processing pressure P2 after changing the bias RF signal to the second bias electric power Pb2 has been described, but it is not limited thereto. For example, the pressure in the processing chamber 1 may be adjusted from the ignition pressure P3 to the processing pressure P2 after supplying the source RF signal to the inductively coupled antenna 70 and before changing the bias RF signal to the second bias electric power Pb2.

[0064] (Example)

[0065] Next, an example for confirming the effects of the embodiment will be described.

[0066] (Example 1)

[0067] In Example 1, for use Figure 1The plasma processing apparatus shown is implemented Figure 2 The plasma ignitability during the plasma processing method of the embodiment shown was confirmed. In Example 1, the first bias electric power Pb1 was set to 0.5 kW, the second bias electric power Pb2 was set to 2.0 kW, and the first source electric power Ps1 was set to 7.5 kW. In Example 1, the pressure before processing P1 was set to the pressure in the state where the exhaust unit 15 had finished pumping, the ignition pressure P3 was set to 20 mTorr (2.7 Pa), and the processing pressure P2 was set to 10 mTorr (1.3 Pa). In Example 1, as the processing gas, CF 4 and O 2 mixed gas (CF 4 / O 2 = 400 sccm / 100 sccm) was used.

[0068] Figure 4 is a graph showing the plasma ignitability during the plasma processing method of the embodiment shown. In Figure 2 , the horizontal axis represents time [seconds], the first vertical axis (the left axis) represents electric power [W], and the second vertical axis (the right axis) represents pressure [mTorr]. In Figure 4 , the thick solid line and the thick dashed line respectively represent the forward wave electric power and the reflected wave electric power of the source RF signal, the thin solid line and the thin dashed line respectively represent the forward wave electric power and the reflected wave electric power of the bias RF signal, and the single dotted line represents the pressure inside the processing container 1. Figure 4 As can be seen from

[0069] as shown, good ignitability was obtained in Example 1. Figure 4 shown, good ignitability was obtained in Example 1.

[0070] (Example 2)

[0071] In Example 2, the plasma ignitability during the plasma processing method of a modified example of the embodiment shown using Figure 1 the plasma processing apparatus shown was confirmed. The electric power, pressure, and processing gas in Example 2 were the same as those in Example 1 respectively. Figure 3 the plasma processing apparatus shown was confirmed. The electric power, pressure, and processing gas in Example 2 were the same as those in Example 1 respectively.

[0072] Figure 5 is a graph showing the plasma ignitability during the plasma processing method of the embodiment shown. In Figure 3 , the horizontal axis represents time [seconds], the first vertical axis (the left axis) represents electric power [W], and the second vertical axis (the right axis) represents pressure [mTorr]. In Figure 5 , the horizontal axis represents time [seconds], the first vertical axis (the left axis) represents electric power [W], and the second vertical axis (the right axis) represents pressure [mTorr]. In Figure 5Among them, the thick solid line and the thick dashed line respectively represent the forward-wave electric power and the reflected-wave electric power of the source RF signal, the thin solid line and the thin dashed line respectively represent the forward-wave electric power and the reflected-wave electric power of the bias RF signal, and the single-dot dash line represents the pressure inside the processing container 1.

[0073] As Figure 5 shown, in Example 2, good ignition performance was also obtained in the same manner as in Example 1.

[0074] (Example 3)

[0075] In Example 3, the plasma ignition performance was confirmed when changing the bias time until the bias electric power changes. In Example 3, the Figure 1 shown plasma processing apparatus was used to implement the Figure 2 shown plasma processing method of the embodiment. In Example 3, the bias time until the bias electric power changes was set to 1 second, 2 seconds, and 3 seconds. The electric power, pressure, and processing gas in Example 3 were the same as those in Example 1.

[0076] Figures 6 to 8 is a graph showing the plasma ignition performance when changing the bias time until the bias electric power changes in the Figure 2 shown plasma processing method. Figure 6 , Figure 7 and Figure 8 respectively show the results when the bias time is set to 1 second, 2 seconds, and 3 seconds. In Figures 6 to 8 , the horizontal axis represents time [seconds], the first vertical axis (the left axis) represents electric power [W], and the second vertical axis (the right axis) represents pressure [mTorr]. In Figures 6 to 8 , the thick solid line represents the forward-wave electric power of the source RF signal, the thin solid line represents the forward-wave electric power of the bias RF signal, and the single-dot dash line represents the pressure inside the processing container 1.

[0077] As Figure 6 shown, when the bias time until the bias electric power changes is set to 1 second, immediately after the bias RF signal is changed from the first bias electric power Pb1 to the second bias electric power Pb2, the forward-wave electric power of the source RF signal substantially becomes zero, and the plasma goes out. In addition, at this time, the bias RF signal is also cut off before reaching 2.0 kW set as the second bias electric power Pb2. As Figure 7 and Figure 8 shown, when the bias time until the bias electric power changes is set to 2 seconds and 3 seconds, good ignition performance is obtained. From these results, it is considered that it is preferable to set the bias time until the bias electric power changes to 2 seconds or more.

[0078] (Example 4)

[0079] In Example 4, the plasma ignition property when changing the process gas was confirmed. In Example 4, the plasma processing apparatus shown in Figure 1 was used to implement the plasma processing method of the embodiment shown in Figure 2 . In Example 4, as the process gas, a mixed gas of CF 4 and O 2 (CF 4 / O 2 ), O 2 , and a mixed gas of CF 4 and Ar (CF 4 / Ar) were used.

[0080] Under the condition of using CF 4 / O 2 as the process gas, the first bias electric power Pb1 was set to 0.5 kW, the second bias electric power Pb2 was set to 2.0 kW, and the first source electric power Ps1 was set to 7.5 kW. In addition, the pressure before processing P1 was set to the pressure in the state exhausted by the exhaust unit 15, the ignition pressure P3 was set to 20 mTorr (2.7 Pa), and the processing pressure P2 was set to 10 mTorr (1.3 Pa).

[0081] Under the condition of using O 2 as the process gas, the first bias electric power Pb1 was set to 0.5 kW, the second bias electric power Pb2 was set to 0.15 kW, and the first source electric power Ps1 was set to 5.0 kW. In addition, the pressure before processing P1 was set to the pressure in the state exhausted by the exhaust unit 15, the ignition pressure P3 was set to 20 mTorr (2.7 Pa), and the processing pressure P2 was set to 30 mTorr (4.0 Pa).

[0082] Under the condition of using CF 4 / Ar as the process gas, the first bias electric power Pb1 was set to 0.5 kW, the second bias electric power Pb2 was set to 5.0 kW, and the first source electric power Ps1 was set to 5.0 kW. In addition, the pressure before processing P1 was set to the pressure in the state exhausted by the exhaust unit 15, the ignition pressure P3 was set to 20 mTorr (2.7 Pa), and the processing pressure P2 was set to 10 mTorr (1.3 Pa).

[0083] Figures 9 to 11 is a graph showing the plasma ignition property when changing the process gas in the plasma processing method shown in Figure 2 . Figure 9 , Figure 10 andFigure 11 respectively represent the results when using CF 4 / O 2 , O 2 and CF 4 / Ar as the processing gas. In Figures 9 to 11 , the horizontal axis represents time [seconds], the first vertical axis (the left axis) represents the electric power [W], and the second vertical axis (the right axis) represents the pressure [mTorr]. In Figures 9 to 11 , the thick solid line represents the forward wave electric power of the source RF signal, the thin solid line represents the forward wave electric power of the bias RF signal, and the single dotted line represents the pressure inside the processing chamber 1.

[0084] As Figures 9 to 11 shown, good ignition performance was obtained in the case of using any of the processing gases.

[0085] (Example 5)

[0086] In Example 5, the plasma ignition performance during multi-step processing was confirmed. In Example 5, the multi-step processing included 4 discharge steps. In Example 5, in the first discharge step, using the Figure 1 shown plasma processing apparatus, the plasma processing method of the Figure 2 shown embodiment was implemented. In the second to fourth discharge steps, plasma ignition was not implemented by capacitive coupling between the metal window 2 and the stage 3, and while supplying the source RF signal to the inductive coupling antenna 70, a bias RF signal was supplied to the base 33.

[0087] Figure 12 is a diagram showing the plasma ignition performance during multi-step processing. In Figure 12 , the horizontal axis represents time [seconds], the first vertical axis (the left axis) represents the electric power [W], and the second vertical axis (the right axis) represents the pressure [mTorr]. In Figure 12 , the thick solid line represents the forward wave electric power of the source RF signal, the thin solid line represents the forward wave electric power of the bias RF signal, and the single dotted line represents the pressure inside the processing chamber 1.

[0088] As Figure 12 shown, good ignition performance was obtained in all the first to fourth discharge steps. From this result, it was shown that in multi-step processing, when plasma ignition was performed in the first discharge step, even if the plasma processing method of the embodiment was not implemented in the second and subsequent discharge steps, plasma ignition could be stably performed.

[0089] (Example 6)

[0090] In Example 6, the influence of the plasma ignited by capacitive coupling on the film formed on the surface of the substrate G was confirmed. In Example 6, using Figure 1 the plasma processing apparatus shown, only the first control in the plasma processing method of the embodiment shown in Figure 2 was implemented. In Example 6, the substrate G having a silicon oxide film and a silicon nitride film formed on the surface as the object films to be evaluated was subjected to the treatment based on the first control, and the film thicknesses of the object films before and after the treatment were measured to calculate the amount of film removal of the object films. In Example 6, the first bias electric power Pb1 was set to 0.5 kW, the ignition pressure P3 was set to 20 mTorr (2.7 Pa), and the treatment time was set to 5 seconds. In Example 6, as the processing gas, a mixed gas of CF 4 and O 2 was used (CF 4 / O 2 = 400 sccm / 100 sccm).

[0091] Figure 13 is a graph showing the amount of film removal of the object film subjected to the treatment based on the first control. In Figure 13 , represents the amount of film removal less than the measurement limit of the film thickness measuring instrument, including the case where the object film is not removed at all and the case where the object film is hardly removed.

[0092] As can be seen from Figure 13 shown, the amounts of film removal of the silicon oxide film and the silicon nitride film subjected to the treatment based on the first control are According to this result, it was shown that the silicon oxide film and the silicon nitride film are not removed at all or hardly removed even when exposed to the plasma generated by capacitive coupling ignition. That is, it was shown that the plasma ignited by capacitive coupling hardly affects the object film.

[0093] In addition, in the above embodiment, the first bias electric power Pb1 is an example of the first electric power, the first source electric power Ps1 is an example of the second electric power, and the second bias electric power Pb2 is an example of the third electric power. Further, the ignition pressure P3 is an example of the first pressure, and the processing pressure P2 is an example of the second pressure.

[0094] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The above embodiments can be omitted, replaced, and changed in various ways without departing from the appended claims and their gist.

Claims

1. A plasma processing device, It is characterized in that include: a processing container, capable of performing plasma processing on a substrate using plasma inside the processing container; A mounting table disposed inside the processing container, capable of mounting the substrate and also serving as a lower electrode; a metal window forming a top of the processing container while being electrically insulated from the processing container and being grounded; an inductive coupling antenna facing the mounting platform across the metal window, and arranged to be electrically insulated from the metal window; and A control unit for controlling the plasma processing, The control unit is capable of performing: A first control of supplying a first high frequency to the mounting table with a first electric power to ignite the plasma through capacitive coupling between the metal window and the mounting table; supplying a second high frequency to the inductively coupled antenna with a second electric power to maintain a second control of the plasma by inductive coupling through the metal window; and A third control is performed to change the electric power of the first high frequency into a third electric power larger than the first electric power, and to perform the plasma processing on the substrate mounted on the mounting table.

2. The plasma processing apparatus according to claim 1, Features: In the third control, after a predetermined time has elapsed from when the second high frequency is supplied to the inductive coupling antenna with the second electric power, the electric power of the first high frequency is changed to the third electric power.

3. The plasma processing device according to claim 1 or 2, Features: A first pressure inside the processing container in the first control is higher than a second pressure inside the processing container when the plasma processing is performed on the substrate.

4. The plasma processing apparatus according to claim 3, Features: In the second control, before the second high frequency is supplied to the inductive coupling antenna with the second electric power, the pressure inside the processing container is changed from the first pressure to the second pressure.

5. The plasma processing device according to any one of claims 1 to 4, Features: The metal window is composed of a plurality of divided windows, and each of the plurality of divided windows is grounded via an impedance adjustment circuit.

6. The plasma processing apparatus according to any one of claims 1 to 5, Features: A processing gas may be supplied into the processing container, the plasma may be ignited from the processing gas in the first control, and the plasma may be maintained in the third control.

7. A plasma processing method, which is a plasma processing method implemented in a plasma processing device, wherein the plasma processing device include: a processing container, capable of performing plasma processing on a substrate using plasma inside the processing container; A mounting table disposed inside the processing container, capable of mounting the substrate and also serving as a lower electrode; a metal window forming a top of the processing container while being electrically insulated from the processing container and being grounded; and an inductive coupling antenna facing the mounting platform across the metal window, and arranged to be electrically insulated from the metal window; The plasma treatment method is characterized by comprising: A step of supplying a first high frequency to the mounting table with a first electric power, and igniting the plasma through capacitive coupling between the metal window and the mounting table; supplying a second high frequency to the inductively coupled antenna with a second electric power to maintain the plasma by inductive coupling through the metal window; and The step of changing the first high-frequency electric power to a third electric power greater than the first electric power, and performing the plasma processing on the substrate mounted on the mounting table.

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