JP2019070182A - Film deposition method - Google Patents

Abstract

To provide a film deposition method in which stress of a film and film density can be set.SOLUTION: A film deposition method according to one embodiment is executed with a substrate mounted on a support table. The film deposition method includes the processes of: supplying a precursor gas including a precursor into an internal space of a chamber body from a gas supply part; supplying a reactive gas into the internal space from the gas supply part; and generating plasma of the reactive gas so as to enhance reaction between the precursor and reactive gas. In the process of generating the plasma of the reactive gas, a ratio of electric power of second high frequency supplied to a lower electrode to electric power of first high frequency supplied to an upper electrode is adjusted, and a phase adjusting circuit adjust a phase of a voltage of the lower electrode relatively to a phase of a voltage of the upper electrode.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present disclosure relate to a film forming method.

  In the manufacture of electronic devices, a deposition process is performed to form a film on a substrate. In the film forming process, a film is formed by the reaction of a precursor and a reactive gas. In one type of film formation process, plasma of reactive gas is used to enhance the reaction.

  The film formation process is required to control the stress of the film. The film formation process which can control the stress of a film is described in patent documents 1-3. In the film forming process described in Patent Document 1, a capacitive coupling type plasma processing apparatus is used. The capacitively coupled plasma processing apparatus has parallel plate electrodes, that is, upper and lower electrodes. In the film forming process described in Patent Document 1, in order to control the stress of the SiN film, the high frequency power supplied to the lower electrode is adjusted with respect to the high frequency power supplied to the upper electrode.

  In the film forming process described in Patent Document 2, an inductive coupling type plasma processing apparatus is used. In the film forming process described in Patent Document 2, high frequency power is adjusted in order to increase the compressive stress of the SiN film.

  In the film forming process described in Patent Document 3, a capacitive coupling type plasma processing apparatus is used. In the film forming process described in Patent Document 3, in order to control the stress of the passivation film, the high frequency power supplied to the lower electrode is adjusted to the high frequency power supplied to the upper electrode.

JP, 2011-23718, A JP 2008-47620 A JP-A-9-298193

  The film-forming process described in patent documents 1-3 controls the stress of the film | membrane formed by adjusting the power of a high frequency. The stress of the film is an important factor related to the film quality, but in addition to the stress of the film, setting the film density, ie, forming a film having a high film density or a film having a low film density It is required to form.

  In a first aspect, there is provided a deposition method performed using a plasma processing apparatus. The plasma processing apparatus includes a chamber body, a gas supply unit, a support, an upper electrode, a high frequency supply unit, and a phase adjustment circuit. An internal space is provided in the chamber body. The gas supply unit is configured to supply the gas to the internal space. The support includes a lower electrode. The support is provided in the interior space and is configured to support a substrate mounted thereon. The upper electrode is provided above the support. The high frequency supply unit generates a first high frequency supplied to the upper electrode and a second high frequency having the same frequency as the first high frequency and supplied to the lower electrode, and the first high frequency The ratio of the power of the second high frequency to the power is adjustable. The phase adjustment circuit is configured to adjust the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode. The film forming method according to the first aspect is performed in a state where the substrate is placed on the support table. This film forming method includes the steps of: supplying a precursor gas containing a precursor from the gas supply unit to the inner space; supplying a reactive gas from the gas supply unit to the inner space; and a precursor and a reactive gas Generating a plasma of reactive gas to enhance the reaction with the reaction. In the step of generating the reactive gas plasma, the ratio of the power of the second high frequency power to the power of the first high frequency power is adjusted, and the self bias potential of the lower electrode is zero or has a positive value. The phase adjustment circuit adjusts the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode.

  In the film forming method according to the first aspect, since the ratio of the power of the second high frequency to the power of the first high frequency is adjusted, it is possible to adjust the stress of the film formed on the substrate. Also, the phase adjustment circuit adjusts the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode such that the self-bias potential of the lower electrode is zero or has a positive value. When the self bias potential of the lower electrode is zero or has a positive value, the energy of ions colliding with the substrate is reduced. Therefore, the film density of the film formed on the substrate is increased.

  In a second aspect, a film forming method performed using a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber body, a gas supply unit, a support, an upper electrode, a high frequency supply unit, and a phase adjustment circuit. An internal space is provided in the chamber body. The gas supply unit is configured to supply the gas to the internal space. The support includes a lower electrode. The support is provided in the interior space and is configured to support a substrate mounted thereon. The upper electrode is provided above the support. The high frequency supply unit generates a first high frequency supplied to the upper electrode and a second high frequency having the same frequency as the first high frequency and supplied to the lower electrode, and the first high frequency The ratio of the power of the second high frequency to the power is adjustable. The phase adjustment circuit is configured to adjust the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode. The film forming method according to the second aspect is performed in a state where the substrate is placed on the support table. This film forming method includes the steps of: supplying a precursor gas containing a precursor from the gas supply unit to the inner space; supplying a reactive gas from the gas supply unit to the inner space; and a precursor and a reactive gas Generating a plasma of reactive gas to enhance the reaction with the reaction. In the step of generating plasma of reactive gas, the ratio of the power of the second high frequency to the power of the first high frequency is adjusted, and the lower part of the phase adjustment circuit is made so that the self bias potential of the lower electrode has a negative value. The phase of the voltage of the electrode is adjusted relative to the phase of the voltage of the upper electrode.

  In the film forming method according to the second aspect, since the ratio of the power of the second high frequency to the power of the first high frequency is adjusted, it is possible to adjust the stress of the film formed on the substrate. Further, the phase adjustment circuit adjusts the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode such that the self bias potential of the lower electrode has a negative value. When the self bias potential of the lower electrode has a negative value, the energy of ions colliding with the substrate is high. Therefore, the film density of the film formed on the substrate is lowered.

  In one embodiment, the high frequency supply comprises a high frequency power supply and a transformer. The transformer has a primary coil, a first secondary coil, and a second secondary coil. The primary coil is electrically connected to the high frequency power supply. The first secondary coil is electromagnetically coupled to the primary coil and electrically connected to the upper electrode. The second secondary coil is electromagnetically coupled to the primary coil and electrically connected to the lower electrode. The transformer is configured to be able to adjust the ratio of the power of the second high frequency power output from the second secondary coil to the power of the first high frequency power output from the first secondary coil . In the step of generating the reactive gas plasma, the transformer adjusts the ratio of the second high frequency power to the first high frequency power.

  In one embodiment, the steps of providing a precursor gas, providing a reactive gas, and generating a plasma of the reactive gas are performed simultaneously. In this embodiment, the film is formed by plasma-enhanced chemical vapor deposition (CVD).

  In one embodiment, during the step of supplying the reactive gas, the step of supplying the precursor gas and the step of generating a plasma of the reactive gas are alternately performed. In this embodiment, a film is formed by plasma-enhanced atomic layer deposition (ALD).

  In one embodiment, the precursor gas is a titanium containing gas and the reactive gas is an oxygen containing gas. In one embodiment, the titanium-containing gas is a titanium halide gas. In one embodiment, the titanium halide gas is titanium tetrachloride gas. In one embodiment, the oxygen containing gas is oxygen gas.

  In a third aspect, a film forming method performed using a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber body, a gas supply unit, a support, an upper electrode, a high frequency supply unit, and a phase adjustment circuit. An internal space is provided in the chamber body. The gas supply unit is configured to supply the gas to the internal space. The support includes a lower electrode. The support is provided in the interior space and is configured to support a substrate mounted thereon. The upper electrode is provided above the support. The high frequency supply unit generates a first high frequency supplied to the upper electrode and a second high frequency having the same frequency as the first high frequency and supplied to the lower electrode, and the first high frequency The ratio of the power of the second high frequency to the power is adjustable. The phase adjustment circuit is configured to adjust the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode. The film forming method according to the third aspect comprises the steps of: (i) performing a film forming process under initial conditions in order to form a first film on a first substrate placed on a support table The film forming process includes (a) supplying a precursor gas containing a precursor from the gas supply unit to the inner space, and (b) supplying a reactive gas from the gas supply unit to the inner space And (c) generating a plasma of the reactive gas to enhance the reaction between the precursor and the reactive gas, wherein the initial condition is a process of generating the plasma of the reactive gas, And (ii) an initial value of an initial value of the ratio of the power of the second high frequency power to the power of the first high frequency power and an initial value of the phase difference of the voltage of the lower electrode to the voltage of the upper electrode; Evaluating the at least one film, wherein an evaluation result including at least a stress of the first film is generated. (Iii) determining the processing conditions of the film forming process based on the evaluation result, and (iv) processing to form a second film on the second substrate placed on the support table. And d) performing a film forming process under conditions. The processing conditions include the ratio of the power of the second high frequency power to the power of the first high frequency power and the phase difference of the voltage of the lower electrode to the voltage of the upper electrode in the step of generating the plasma of the reactive gas. In the process of determining the processing conditions, the ratio in the processing conditions is set based on the evaluation result.

  In the film forming method according to the third aspect, the film density of the film to be formed can be set by setting the phase difference of the voltage of the lower electrode to the voltage of the upper electrode. Further, based on the stress of the first film formed by the film forming process under the initial conditions, the ratio of the power of the second high frequency to the power of the first high frequency at the time of forming the second film is adjusted. Therefore, it is possible to bring the stress of the second film close to the desired stress.

  In one embodiment, the polarity of the self-bias potential of the lower electrode when the film formation process is performed under the processing conditions is the polarity of the self-bias potential of the lower electrode when the film formation process is performed under the initial conditions. It is the same.

  In one embodiment, relative to the initial value of the ratio included in the initial conditions, to reduce the compressive stress of the second film relative to the stress of the first film or to increase the tensile stress of the second film. The ratio included in the processing conditions is increased. Included in the processing conditions for the initial value of the ratio included in the initial conditions to reduce the tensile stress of the second film relative to the stress of the first film or to increase the compressive stress of the second film Ratio is reduced.

  As described above, the film density can be set in addition to the stress of the film.

It is a flowchart which shows the film-forming method which concerns on one Embodiment. It is a figure which shows the plasma processing apparatus of one Embodiment which can be used in execution of the film-forming method which concerns on various embodiment. FIG. 3 is a partially broken perspective view showing a transformer that can be used as a transformer of the plasma processing apparatus shown in FIG. 2; Fig. 4 schematically illustrates the three coils of the transformer shown in Fig. 3; (A) of FIG. 5 is a diagram showing the time change of the voltage of the upper electrode and the voltage of the lower electrode when the phase difference Δφ is substantially zero, and (b) of FIG. 5 shows that the phase difference Δφ is substantially zero It is a figure which shows the time change of the electric potential of plasma in the case of being, and the electric potential of a board | substrate. (A) of FIG. 6 is a diagram showing temporal changes of the voltage of the upper electrode and the voltage of the lower electrode when the phase difference Δφ is not zero, and (b) of FIG. 6 is a case when the phase difference Δφ is not zero It is a figure which shows the time change of the electric potential of plasma, and the electric potential of a board | substrate. FIG. 3 schematically shows another transformer that can be used as a transformer of the plasma processing apparatus shown in FIG. 2; It is a timing chart relevant to the film-forming method shown in FIG. FIG. 9 is a flowchart showing a film forming method according to another embodiment. It is a flowchart which shows the film-forming method which concerns on another embodiment. It is a graph which shows the result of the 1st experiment. It is a graph which shows the result of the 2nd experiment. It is a graph which shows the result of the 3rd experiment.

  Hereinafter, various embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals.

  FIG. 1 is a flow chart showing a film forming method according to an embodiment. The film forming method shown in FIG. 1 (hereinafter referred to as “method MT1”) is a method of forming a film on a substrate. In the method MT1, a plasma processing apparatus is used.

  FIG. 2 is a view showing a plasma processing apparatus according to an embodiment that can be used to execute a film forming method according to various embodiments. The plasma processing apparatus 10 shown in FIG. 2 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 10 includes a chamber body 12. The chamber body 12 has a substantially cylindrical shape and extends in the vertical direction. The chamber body 12 has a substantially cylindrical side wall portion and a bottom portion continuous with the lower end of the side wall portion. The chamber body 12 provides an internal space 12s. The chamber body 12 is formed of a metal such as aluminum. A coating having plasma resistance is formed on the inner wall surface of the chamber body 12. The coating having plasma resistance may be a ceramic film such as an alumite film or a yttrium oxide film. The chamber body 12 is grounded.

  A passage 12 p is formed in the side wall of the chamber body 12. The substrate W passes through the passage 12 p when being transferred from the outside of the chamber body 12 to the internal space 12 s and when being transferred from the inside space 12 s to the outside of the chamber body 12. The passage 12p can be opened and closed by a gate valve 12g. The gate valve 12 g is provided along the side wall of the chamber body 12.

  A support 14 is provided in the internal space 12s of the chamber body. The support 14 is configured to support a substrate W placed thereon. The support 14 is supported by a support 15. The support 15 is insulative and extends upward from the bottom of the chamber body 12.

  The support 14 includes a lower electrode 16. The lower electrode 16 has a substantially disk shape. The lower electrode 16 is formed of a conductive material such as aluminum. In one embodiment, the support 14 further includes an electrostatic chuck 18. The electrostatic chuck 18 is provided on the lower electrode 16. The substrate W is placed on the electrostatic chuck 18. The electrostatic chuck 18 includes a dielectric film and an electrode embedded in the dielectric film. The electrode of the electrostatic chuck 18 may be a film having conductivity. A power supply is connected to the electrode of the electrostatic chuck 18 via a switch. By applying a voltage from the power source to the electrode of the electrostatic chuck 18, electrostatic attraction is generated between the electrostatic chuck 18 and the substrate W. The substrate W is attracted to the electrostatic chuck 18 and held by the electrostatic chuck 18 by the generated electrostatic attractive force.

  An upper electrode 20 is provided above the support 14. A portion of the internal space 12s is interposed between the upper electrode 20 and the support 14. In one embodiment, the upper end of the chamber body 12 is open. The upper electrode 20 is supported at the upper end of the chamber body 12 via a member 21. The member 21 has an insulating property. The upper electrode 20, together with the member 21, closes the opening at the upper end of the chamber body 12.

  The upper electrode 20 is formed of one or more parts having conductivity. One or more components that constitute the upper electrode 20 may be formed of a material such as aluminum or silicon. Alternatively, the upper electrode 20 may be formed of one or more parts having conductivity and one or more parts having insulation. A plasma resistant film may be formed on the surface of the upper electrode 20.

  In the upper electrode 20, a plurality of gas discharge holes 20a and gas diffusion chambers 20b are formed. The plurality of gas discharge holes 20a extend downward from the gas diffusion space 20b to the lower surface of the upper electrode 20 on the inner space 12s side. A gas supply unit 22 is connected to the gas diffusion space 20b. The gas supply unit 22 is configured to supply a gas to the internal space 12s. The gas supply unit 22 includes, for example, a plurality of gas sources, a plurality of flow rate controllers such as mass flow controllers, and a plurality of valves. Each of the plurality of gas sources is connected to the gas diffusion space 20b via the corresponding flow rate controller among the plurality of flow rate controllers and the corresponding valve among the plurality of valves. The gas supply unit 22 adjusts the flow rate of the gas from the selected gas source among the plurality of gas sources, and supplies the gas to the gas diffusion space 20b. The gas supplied to the gas diffusion space 20b is supplied to the internal space 12s from the plurality of gas discharge holes 20a.

  An exhaust device 24 is connected to the bottom of the chamber body 12. The exhaust device 24 is provided in communication with the internal space 12s. The exhaust device 24 has a pressure control device such as a pressure control valve, and a vacuum pump such as a turbo molecular pump or a dry pump. By operating the exhaust device 24, the gas present in the internal space 12 s is exhausted through the space 12 v between the support 14 and the side wall of the chamber body 12. Further, the pressure in the internal space 12s is adjusted to a designated pressure by the exhaust system 24.

  The plasma processing apparatus 10 further includes a high frequency supply unit 26, a phase adjustment circuit 281, a phase adjustment circuit 282, and a control unit 30. The high frequency supply unit 26 generates a first high frequency and a second high frequency. The first high frequency is a high frequency supplied to the upper electrode 20. The second high frequency is a high frequency supplied to the lower electrode 16 and has the same frequency as the first high frequency. The high frequency supply unit 26 is configured to be able to adjust the ratio R (i.e., P2 / P1) of the power of the second high frequency to the power of the first high frequency. Here, P1 is the power of the first high frequency, and P2 is the power of the second high frequency.

  The control unit 30 may be a computer device, and may include a processor, a storage device such as a memory, an input device such as a keyboard, a mouse, and a touch panel, a display device, an input / output interface of signals, and the like. The storage device of the control unit 30 stores a control program and recipe data. The processor of the control unit 30 executes a control program to control each unit of the plasma processing apparatus 10 according to the recipe data. The method MT <b> 1 and the film forming method according to various embodiments described later are executed by the control unit 30 controlling each part of the plasma processing apparatus 10.

  In one embodiment, the high frequency supply unit 26 includes a high frequency power supply 261 and a transformer 100. The high frequency power supply 261 is configured to generate a high frequency. The high frequency power from the high frequency power supply 261 is supplied to the primary coil of the transformer 100.

  FIG. 3 is a partially cutaway perspective view showing a transformer that can be used as a transformer of the plasma processing apparatus shown in FIG. FIG. 4 schematically illustrates the three coils of the transformer shown in FIG. The transformer 100A shown in FIGS. 3 and 4 can be used as the transformer 100 of the plasma processing apparatus 10. The transformer 100A includes a rotating shaft 112, a primary coil 101A, a first secondary coil 102A, and a second secondary coil 103A. The first secondary coil 102 </ b> A and the second secondary coil 103 </ b> A constitute a secondary coil pair 106. In one embodiment, transformer 100A includes support member 122, support member 124, support column 126, support member 128, support member 130, support member 132, support member 134, terminal 101a, terminal 101b, terminal 102a, terminal 102b, terminal It further comprises a terminal 103a and a terminal 103b.

  The rotating shaft 112 has a substantially cylindrical shape. The rotation axis 112 is rotatably provided about its central axis RX. In one embodiment, the rotation shaft 112 is rotatably supported by the support member 122 and the support member 124. The support member 122 and the support member 124 are plate-like members, and have a substantially rectangular planar shape. The support member 122 and the support member 124 are formed of an insulator. The support member 122 and the support member 124 are provided so as to intersect or be substantially orthogonal to the central axis RX, and are arranged along the direction RD such that the thickness direction thereof substantially coincides with the direction RD in which the central axis RX extends. It is done. One end of a support 126 is fixed to the corner of the support member 122, and the other end of the support 126 is fixed to the corner of the support member 124. One end of the rotation shaft 112 penetrates the support member 122 and protrudes from the support member 122. One end of the rotating shaft 112 is connected to a drive mechanism (for example, a motor).

  The support member 128 and the support member 130 are substantially disk-shaped members, and are formed of an insulator. The support member 128 and the support member 130 are provided so as to intersect or be substantially orthogonal to the central axis RX between the support member 122 and the support member 124 so that the plate thickness direction thereof substantially coincides with the direction RD. It is arranged along the direction RD. The support member 132 and the support member 134 are substantially disk-shaped members, and are formed of an insulator. The support member 132 and the support member 134 are provided so as to intersect or be substantially orthogonal to the central axis RX between the support member 128 and the support member 130 so that the plate thickness direction thereof substantially coincides with the direction RD. It is arranged along the direction RD. The rotation shaft 112 passes through the centers of the support member 128, the support member 130, the support member 132, and the support member 134. The support member 128, the support member 130, the support member 132, and the support member 134 are fixed to the rotation shaft 112.

  The primary coil 101A extends around a first axis AX1 orthogonal to the central axis RX. In one embodiment, the first axis AX1 is orthogonal to the central axis RX at a midpoint between the support member 122 and the support member 124. The primary coil 101A is wound around the first axis AX1 so as to alternately pass through the outside of the support member 122 and the outside of the support member 124.

  One end of the primary coil 101A is connected to the terminal 101a. In one embodiment, the terminal 101a is provided on one surface 122a of the support member 122 (a surface facing the outside of the transformer 100A). The other end of the primary coil 101A is connected to the terminal 101b. In one embodiment, the terminal 101b is provided on one surface 124a of the support member 124 (the surface facing the outside of the transformer 100A).

  The first secondary coil 102A extends around a second axis AX2. The second axis AX2 is orthogonal to the central axis RX in a region surrounded by the primary coil 101A. In one embodiment, the second axis AX2 is orthogonal to the central axis RX at a midpoint between the support member 128 and the support member 130. The first secondary coil 102A is wound around the second axis AX2 so as to alternately pass through the outside of the support member 128 and the outside of the support member 130. The first secondary coil 102 </ b> A is supported by the rotation shaft 112 via the support member 128 and the support member 130.

  One end of the first secondary coil 102A is connected to the terminal 102a. The other end of the first secondary coil 102A is connected to the terminal 102b. In one embodiment, the terminals 102 a and 102 b are provided on one surface 122 a of the support member 122. The rotating shaft 112 includes a first conductor and a second conductor provided coaxially, and one end of the first secondary coil 102A is connected to the first conductor, and the first secondary The other end of the coil 102A is connected to the second conductor. The first conductor is connected to the terminal 102 a via a slip ring in the rotary connector 140. Also, the second conductor is connected to the terminal 102 b through another slip ring in the rotary connector 140.

  The second secondary coil 103A extends around a third axis AX3. The third axis AX3 is orthogonal to the central axis RX in a region surrounded by the primary coil 101A. The third axis AX3 intersects the second axis AX2. The third axis AX3 and the second axis AX2 form a predetermined angle θp between each other. The angle θp is not limited, but is, for example, 90 degrees. In one embodiment, the third axis AX3 is orthogonal to the central axis RX at the middle of the support member 132 and the support member 134. The second secondary coil 103A is wound around the third axis AX3 so as to alternately pass through the outside of the support member 132 and the outside of the support member 134. The second secondary coil 103 </ b> A is supported by the rotation shaft 112 via the support member 132 and the support member 134. An insulation distance is secured between the second secondary coil 103A and the first secondary coil 102A.

  One end of the second secondary coil 103A is connected to the terminal 103a. The other end of the second secondary coil 103A is connected to the terminal 103b. In one embodiment, the terminals 103 a and the terminals 103 b are provided on one surface 124 a of the support member 124. The rotating shaft 112 includes a third conductor and a fourth conductor provided coaxially, one end of the second secondary coil 103A is connected to the third conductor, and the second secondary The other end of the coil 103A is connected to the fourth conductor. The third conductor is connected to the terminal 103 a via the slip ring of another rotary connector provided in the vicinity of the support member 124. Also, the fourth conductor is connected to the terminal 103b via another slip ring in the other rotary connector.

  When transformer 100A is used as transformer 100 of plasma processing apparatus 10, terminals 101a and 101b are electrically connected to high frequency power supply 261 as shown in FIG. Also, the terminal 101b is electrically grounded. The terminal 102 a is electrically connected to the upper electrode 20 via the phase adjustment circuit 281. The terminal 103 a is electrically connected to the lower electrode 16 via the phase adjustment circuit 282. The terminal 102 b and the terminal 103 b are electrically grounded.

  The phase adjustment circuit 281 and the phase adjustment circuit 282 are configured to adjust the phase of the voltage of the lower electrode 16 relatively to the phase of the voltage of the upper electrode 20. The phase adjustment circuit 281 is electrically connected to the upper electrode 20. In one embodiment, the phase adjustment circuit 281 includes a capacitor 281a and a variable inductor 281b. The capacitor 281a and the variable inductor 281b are connected in series between the upper electrode 20 and the terminal 102a. In one embodiment, one end of capacitor 281a is connected to terminal 102a. The other end of the capacitor 281a is connected to one end of the variable inductor 281b. The other end of the variable inductor 281 b is electrically connected to the upper electrode 20.

  The phase adjustment circuit 282 is electrically connected to the lower electrode 16. In one embodiment, the phase adjustment circuit 282 includes a capacitor 282a and a variable inductor 282b. The capacitor 282a and the variable inductor 282b are connected in series between the lower electrode 16 and the terminal 103a. In one embodiment, one end of capacitor 282a is connected to terminal 103a. The other end of the capacitor 282a is connected to one end of the variable inductor 282b. The other end of the variable inductor 282 b is electrically connected to the lower electrode 16.

  When the transformer 100A is used as the transformer 100 of the plasma processing apparatus 10, when the high frequency power from the high frequency power supply 261 is supplied to the primary coil 101A, the primary coil 101A is substantially parallel to the direction in which the first axis AX1 extends. Generates magnetic flux in the direction. Further, by adjusting the rotation angle of the secondary coil pair 106, the amount of magnetic flux passing through the first secondary coil 102A and the amount of magnetic flux passing through the second secondary coil 103A are adjusted. An induced electromotive force is generated in the first secondary coil 102A according to the amount of magnetic flux passing therethrough, and a first high frequency is output from the first secondary coil 102A. In addition, an induced electromotive force is generated in the second secondary coil 103A according to the amount of magnetic flux passing through it, and a second high frequency is output from the second secondary coil 103A. Therefore, according to transformer 100A, the ratio of the power of the second high frequency to the power of the first high frequency can be adjusted.

  Further, by adjusting the inductance of the variable inductor of at least one of the phase adjustment circuit 281 and the phase adjustment circuit 282, the phase of the voltage of the lower electrode 16 relative to the phase of the voltage of the upper electrode 20 Is adjusted. That is, the phase difference Δφ of the voltage of the lower electrode 16 with respect to the voltage of the upper electrode 20 is determined by the inductance of the variable inductor of at least one phase adjustment circuit.

  (A) of FIG. 5 is a diagram showing the time change of the voltage of the upper electrode and the voltage of the lower electrode when the phase difference Δφ is substantially zero, and (b) of FIG. 5 shows that the phase difference Δφ is substantially zero It is a figure which shows the time change of the electric potential of plasma in the case of being, and the electric potential of a board | substrate. (A) of FIG. 6 is a diagram showing temporal changes of the voltage of the upper electrode and the voltage of the lower electrode when the phase difference Δφ is not zero, and (b) of FIG. 6 is a case when the phase difference Δφ is not zero It is a figure which shows the time change of the electric potential of plasma, and the electric potential of a board | substrate. When the phase difference Δφ is substantially zero, the self-bias potential Vdc (DC self-bias potential) of the lower electrode 16 becomes zero or a positive value. On the other hand, when the phase difference Δφ is not zero, the self-bias potential Vdc of the lower electrode 16 has a negative value.

  When the phase difference Δφ is substantially zero as shown in (a) of FIG. 5, that is, when the phase of the voltage of the upper electrode 20 and the phase of the voltage of the lower electrode 16 are substantially aligned, As shown in (b), the difference between the potential of plasma and the potential of the substrate W is small, and the self-bias potential Vdc becomes zero or a positive value. When the difference between the potential of the plasma and the potential of the substrate W is small and the self-bias potential Vdc is zero or a positive value, ions in the plasma collide with the substrate with relatively small energy.

  If the phase difference Δφ is not zero as shown in (a) of FIG. 6, that is, if the phase of the voltage of the upper electrode 20 and the phase of the voltage of the lower electrode 16 are not in phase, FIG. As shown, a large difference occurs between the potential of the plasma and the potential of the substrate W, and the self-bias potential Vdc becomes a negative value. When the difference between the potential of the plasma and the potential of the substrate W is large and the self bias potential Vdc is a negative value, ions in the plasma collide with the substrate with a large amount of energy.

  As described above, the phase of the voltage of the lower electrode 16 is adjusted relative to the phase of the voltage of the upper electrode 20 by at least one of the phase adjustment circuit 281 and the phase adjustment circuit 282, thereby the potential of the plasma And the potential of the substrate W, and the self-bias potential Vdc can be adjusted, and hence the energy of ions colliding with the substrate W can be adjusted.

  FIG. 7 schematically shows another transformer that can be used as a transformer of the plasma processing apparatus shown in FIG. Transformer 100B shown in FIG. 7 can be used as transformer 100 of plasma processing apparatus 10 shown in FIG.

  The transformer 100B includes a primary coil 101B, a first secondary coil 102B, and a second secondary coil 103B. One end of the primary coil 101B is a terminal 101a, and the other end is a terminal 101b. The terminal 101 a and the terminal 101 b are connected to the high frequency power supply 261. The terminal 101b is electrically grounded.

  The first secondary coil 102B and the second secondary coil 103B are electromagnetically coupled to the primary coil 101B. One end of the first secondary coil 102B is a terminal 102a. The terminal 102 a is electrically connected to the upper electrode 20 via the phase adjustment circuit 281. Further, one end of the second secondary coil 103B is a terminal 103a. The terminal 103 a is electrically connected to the lower electrode 16 via the phase adjustment circuit 282.

  In the transformer 100B, the first secondary coil 102B and the second secondary coil 103B are formed from a single coil. Specifically, the secondary side of the transformer 100B has a single coil, and the single coil has a plurality of taps 100t. The plurality of taps 100t are configured to be selectively connected to the ground. In the transformer 100B, one side of the single coil becomes the first secondary coil 102B and the other side becomes the second secondary coil 103B with respect to the tap selected to be connected to the ground. According to this transformer 100B, the ratio of the second high frequency power output from the second secondary coil 103B to the first high frequency power output from the first secondary coil 102B is adjusted It can be done.

  Referring back to FIG. 1, the method MT1 will be described. Hereinafter, the method MT1 will be described by taking the case where the plasma processing apparatus 10 is used as an example. However, other plasma processing apparatus may be used in the implementation of method MT1. Further, in the following description, FIG. 8 will be referred to together with FIG. FIG. 8 is a timing chart related to the film forming method shown in FIG. In FIG. 8, the horizontal axis indicates time. In FIG. 8, the vertical axis indicates the flow rate of the carrier gas, the flow rate of the reactive gas, the flow rate of the precursor gas, and the power of the high frequency (first high frequency and second high frequency). Note that, in step ST3, when the ratio R is zero, it is to be noted that the power of the second high frequency is zero.

  The method MT1 is performed in a state where the substrate W is mounted on the support 14 of the plasma processing apparatus 10. In the method MT1, a film forming process DP1 is performed. In the film forming process DP1, a film is formed by plasma-enhanced atomic layer deposition (PEALD). The film forming process DP1 includes a process ST1, a process ST2, and a process ST3. During the execution of the film forming process DP1, the pressure in the internal space 12s is reduced by the exhaust device 24 to a designated pressure.

In the process ST1, the reactive gas is supplied to the internal space 12s. In the film forming process DP1 according to the embodiment, as shown in FIG. 8, the reactive gas is supplied to the internal space 12s from the start time to the end time. Therefore, the process ST1 is continued over the execution period of the film forming process DP1. The reactive gas is a gas that reacts with a precursor described later. When the film to be formed on the substrate W is a titanium oxide film (TiO ₂ film), the reactive gas is an oxygen-containing gas. The oxygen-containing gas may include one or more of oxygen gas (O ₂ gas), CO gas, CO ₂ gas, and the like.

  In the method MT1, as shown in FIG. 8, the carrier gas may be supplied to the internal space 12s over the execution period of the film forming process DP1. The carrier gas is an inert gas. The carrier gas may include one or more noble gases such as He gas, Ne gas, Ar gas, Kr gas, and Xe gas.

As shown in FIGS. 1 and 8, in the film forming process DP1, the process ST2 and the process ST3 are alternately performed. In step ST2, the precursor gas is supplied to the inner space 12s. The precursor gas is a gas containing a precursor, and the precursor contains an element that constitutes a film to be formed on the substrate W. When the film to be formed on the substrate W is a titanium oxide film (TiO ₂ film), the precursor gas is a titanium-containing gas. The titanium containing gas may be a halogenated titanium gas. The halogenated titanium gas is, for example, titanium tetrachloride gas (TiCl ₄ gas). In the process ST2, the supply of the first high frequency and the second high frequency is stopped. That is, in the process ST2, plasma is not generated in the inner space 12s. By performing the process ST2, the precursor is adsorbed to the substrate W.

  As shown in FIG. 8, in a period PA between the execution period of step ST2 and the execution period of step ST3, the supply of precursor gas to the inner space 12s is stopped. During this period PA, a purge for discharging the precursor gas from the inner space 12s is performed. Further, in the period PA, the supply of the first high frequency and the second high frequency is stopped. That is, in the period PA, no plasma is generated in the inner space 12s.

  As shown in FIGS. 1 and 8, in step ST3, a plasma of a reactive gas is generated to enhance the reaction between the precursor and the reactive gas. Specifically, in step ST3, the first high frequency is supplied to the upper electrode 20, and the second high frequency is supplied to the lower electrode 16. In step ST3, when the ratio R is zero, the power of the second high frequency is zero, and the second high frequency is not supplied to the lower electrode 16. When step ST3 is performed, a plasma of a reactive gas is generated in the internal space 12s. A film is formed on the substrate by reacting ions and / or radicals in the plasma of the reactive gas with precursors on the substrate.

  In step ST3 of one embodiment, the phase of the voltage of the lower electrode 16 is adjusted by the phase adjustment circuit 281 and / or the phase adjustment circuit 282 so that the ratio R is adjusted and the self bias potential Vdc is zero or has a positive value. It is adjusted relative to the phase of the voltage of the upper electrode 20. The ratio R is adjusted so that the stress of the film formed on the substrate W is a desired pressure. The larger the ratio R, the smaller the compressive stress of the film or the larger the tensile stress of the film. On the other hand, the smaller the ratio R, the smaller the tensile stress of the film or the larger the compressive stress of the film. The self bias potential Vdc is adjusted such that a film having a desired film density is formed on the substrate W. When the self bias potential Vdc is zero or has a positive value, the energy of ions colliding with the substrate W (or a precursor on the substrate W) is reduced. Therefore, the film density of the film formed on the substrate W is increased. That is, the film density of the film becomes higher as the positive polarity self bias potential Vdc is larger.

  In step ST3 of another embodiment, the phase adjustment circuit 281 and / or the phase adjustment circuit 282 causes the voltage phase of the lower electrode 16 to be adjusted by the phase adjustment circuit 281 and / or the phase adjustment circuit 282 so that the ratio R is adjusted and the self bias potential Vdc has a negative value. It is adjusted relative to the phase of the voltage. The ratio R is adjusted so that the stress of the film formed on the substrate W is a desired pressure. The larger the ratio R, the smaller the compressive stress of the film or the larger the tensile stress of the film. On the other hand, the smaller the ratio R, the smaller the tensile stress of the film or the larger the compressive stress of the film. The self bias potential Vdc is adjusted such that a film having a desired film density is formed on the substrate W. When the self bias potential Vdc has a negative value, the energy of ions colliding with the substrate W (or a precursor on the substrate W) is increased. Therefore, the film density of the film formed on the substrate W becomes low. That is, the film density of the film is lower as the self bias potential Vdc is lower. In other words, the larger the absolute value of the negative self-bias potential Vdc, the lower the film density of the film.

  As shown in FIG. 8, in the period PB between the execution period of the process ST3 and the execution period of the process ST2, the supply of the first high frequency wave and the second high frequency wave is stopped. That is, in this period PB, purge is performed without generating plasma.

  Next, step ST4 is performed. In step ST4, it is determined whether the stop condition is satisfied. The stop condition is determined to be satisfied when the number of executions of the cycle including step ST2 and step ST3 has reached a predetermined number. The predetermined number of times is one or more. If it is determined in step ST4 that the stop condition is not satisfied, step ST2 is executed again. On the other hand, when it is determined in step ST4 that the stop condition is satisfied, the film forming process DP1 ends, and the execution of the method MT1 ends.

  Hereinafter, FIG. 9 will be referred to. FIG. 9 is a flowchart showing a film forming method according to another embodiment. Hereinafter, the film forming method (hereinafter, referred to as “method MT2”) illustrated in FIG. 9 will be described by taking the case where the plasma processing apparatus 10 is used as an example. However, other plasma processing apparatus may be used in the implementation of method MT2.

  The method MT2 is performed in a state where the substrate W is mounted on the support 14 of the plasma processing apparatus 10. In the method MT2, a film forming process DP2 is performed. The film forming process DP2 includes a process ST21, a process ST22, and a process ST23. During the film forming process DP2, the pressure in the internal space 12s is reduced by the exhaust device 24 to a designated pressure. In addition, the carrier gas may be supplied to the internal space 12s over the execution period of the film forming process DP2. The carrier gas is an inert gas. The carrier gas may include one or more noble gases such as He gas, Ne gas, Ar gas, Kr gas, and Xe gas.

  In process ST21, precursor gas is supplied to internal space 12s. The precursor gas used in step ST21 may be the same gas as the precursor gas used in step ST2. In step ST22, the reactive gas is supplied to the internal space 12s. The reactive gas used in step ST22 may be the same gas as the reactive gas used in step ST1. In step ST23, a plasma of a reactive gas is generated to enhance the reaction between the precursor and the reactive gas. Specifically, in step ST23, the first high frequency is supplied to the upper electrode 20, and the second high frequency is supplied to the lower electrode 16.

  In step ST23, the ratio R is adjusted, and the self-bias potential Vdc is adjusted by the phase adjustment circuit 281 and / or the phase adjustment circuit 282. Adjustment of the ratio R and the self-bias potential Vdc in step ST23 is performed in the same manner as step ST3 of method MT1. In step ST23, when the ratio R is zero, the power of the second high frequency is zero, and the second high frequency is not supplied to the lower electrode 16.

  In the film forming process DP2, the process ST21, the process ST22, and the process ST23 are simultaneously performed. Therefore, in the film forming process DP2, film formation is performed by plasma-enhanced chemical vapor deposition (PECVD).

  Hereinafter, FIG. 10 will be referred to. FIG. 10 is a flow chart showing a film forming method according to still another embodiment. Hereinafter, the film forming method (hereinafter, referred to as “method MT3”) illustrated in FIG. 10 will be described by taking the case where the plasma processing apparatus 10 is used as an example. However, other plasma processing apparatus may be used in the implementation of method MT3.

In the method MT3, first, the process ST31 is performed. The process ST31 is performed in a state where the first substrate is mounted on the support base 14. In step ST31, a film forming process is performed under initial conditions. The film forming process is the film forming process DP1 or the film forming process DP2 described above. The initial conditions are the initial value Ri of the ratio R and the initial value Δφ of the phase difference Δφ of the voltage of the lower electrode 16 with respect to the voltage of the upper electrode 20 in the step of generating plasma of reactive gas (step ST3 or step ST23). including _i . When the film forming process DP1 is performed in step ST31, in step ST3, the ratio R is set to an initial value Ri, the phase difference [Delta] [phi is set to an initial value [Delta] [phi _i. When the film forming process DP2 is performed in step ST31, the ratio R is set to the initial value Ri and the phase difference Δφ is set to the initial value Δφ _i in step ST23. As a result of the execution of step ST31, a first film is formed on the first substrate.

  In the subsequent step ST32, the first film is evaluated. The evaluation result obtained in step ST32 includes at least the stress of the first film. The stress of the first film can be measured by using a stress measuring device. The stress measurement device can be determined, for example, from the radius of curvature of the substrate before and after the formation of the first film. In one embodiment, the evaluation result obtained in step ST32 may include a parameter reflecting the density of the first film. The parameter reflecting the density of the first film may be, for example, the wet etching rate of the first film. The wet etching rate of the first film can be obtained, for example, by etching the first film using dilute hydrofluoric acid. If the wet etching rate of the first film is high, the film density of the first film is low. If the wet etching rate of the first film is low, the film density of the first film is high.

  In the subsequent process ST33, the processing conditions of the film forming process are determined based on the evaluation result obtained in the process ST32. The following step ST34 is performed in a state where the second substrate is mounted on the support base 14. In step ST34, a film forming process is performed to form a second film on the second substrate. The film forming process performed in the process ST34 is the film forming process DP1 or the film forming process DP2, and is the same film forming process as the film forming process performed in the process ST31. However, although the film formation process is performed under the initial conditions in the process ST31, the film formation process is performed under the process conditions determined in the process ST33 in the process ST34. The processing conditions include at least the ratio R in the step (step ST3 or step ST23) of generating the plasma of the reactive gas. The processing conditions may further include a phase difference Δφ of the voltage of the lower electrode 16 with respect to the voltage of the upper electrode 20.

In one embodiment, the polarity of the self-bias potential Vdc at the time of execution of step ST3 or step ST23 included in the film formation process at step ST34 is the same as the time of execution of step ST3 or step ST23 included in the film formation process at step ST31. It is identical to the polarity of the bias potential Vdc. In order to set the polarity of the self-bias potential Vdc, for example, the phase difference Δφ in the processing conditions is set to the same phase difference as the initial value Δφ _i of the phase difference in the initial conditions. In this embodiment, in step ST33, the ratio R in the processing conditions is set to reduce the difference between the stress of the first film and the desired stress. In step ST33, the initial value Ri of the ratio included in the initial conditions is set to reduce the compressive stress of the second film with respect to the stress of the first film or to increase the tensile stress of the second film. The ratio R included in the processing conditions is increased. Alternatively, relative to the initial value Ri of the ratio included in the initial conditions to reduce the tensile stress of the second film relative to the stress of the first film or to increase the compressive stress of the second film The ratio R included in the processing conditions is reduced. In step ST3 or step ST23 executed in step ST34, the power of the first high frequency power and the power of the second high frequency power are set based on the ratio R included in the processing conditions.

  In another embodiment, in step ST33, in addition to the ratio R of the processing conditions, the phase difference Δφ of the processing conditions is also set based on the evaluation result of the step ST32. The processing condition phase difference Δφ is determined based on the parameter reflecting the density of the first film. If it is determined from this parameter that the film density of the second film should be increased, then Δφ is reduced. On the other hand, if it is determined from this parameter that the film density of the second film should be reduced, Δφ is increased.

  In the method MT3, it is possible to set the film density of the second film by setting the phase difference Δφ. Further, by adjusting the ratio R at the time of forming the second film based on the stress of the first film, it is possible to bring the stress of the second film closer to a desired stress.

  Although various embodiments have been described above, various modifications can be made without being limited to the above-described embodiments. For example, the plasma processing apparatus 10 may not have one of the phase adjustment circuit 281 and the phase adjustment circuit 282. Also, the film formed by the method MT1 and the method MT2, and the first film and the second film formed by the method MT3 may be any film. Such a film may be a silicon oxide film, a silicon nitride film, a tungsten-containing film or the like. The precursor gas and the reactive gas can be appropriately selected according to the type of film to be formed.

  Hereinafter, some experiments performed to evaluate the method of the above-described embodiment will be described. The experiments described below do not limit the scope of the present disclosure.

  (First experiment)

  In the first experiment, using the plasma processing apparatus 10 having the transformer 100A as the transformer 100, the energy of ions incident on a substrate mounted on the support 14 was measured. In the first experiment, plasma was generated under each of the first to sixth conditions, and the energy of ions (average ion energy) was measured. The conditions of the first experiment are shown below.

<Conditions of first experiment>
Pressure of internal space 12s: 66.5 Pa
Flow rate of argon gas contained in the mixed gas supplied to the internal space 12s: 1000 sccm
Flow rate of oxygen gas contained in the mixed gas supplied to the internal space 12s: 500 sccm
First condition High frequency of high frequency power supply 261: 450 kHz, 300 W
Ratio R: 0.25
Phase difference Δφ: 166 °
Second condition High frequency of high frequency power supply 261: 450 kHz, 300 W
Ratio R: 0.00
Phase difference Δφ: 15 °
Third condition High frequency of high frequency power supply 261: 450 kHz, 300 W
Ratio R: 0.67
Phase difference Δφ: 11 °
Fourth condition High frequency of high frequency power supply 261: 450 kHz, 1000 W
Ratio R: 0.25
Phase difference Δφ: 166 °
Fifth condition High frequency of high frequency power supply 261: 450 kHz, 1000 W
Ratio R: 0.00
Phase difference Δφ: 15 °
Sixth Condition High Frequency of High Frequency Power Supply 261: 450 kHz, 1000 W
Ratio R: 0.67
Phase difference Δφ: 11 °

  FIG. 11 shows the result of the first experiment. In the graph of FIG. 11, the horizontal axis indicates the self-bias potential Vdc, and the vertical axis indicates the average ion energy. As can be seen from FIG. 11 and the first to sixth conditions described above, the phase difference Δφ has a large value even if the ratio R is small, that is, even if the power of the second high frequency supplied to the lower electrode 16 is low. By setting the value to, it is possible to set the self-bias potential Vdc low, that is, when the self-bias potential Vdc has a negative polarity, the absolute value thereof can be set large. In addition, even if the power of the second high frequency supplied to the lower electrode 16 is low, it is confirmed that ions having high energy can be irradiated to the substrate by setting the phase difference Δφ to a large value.

  (Second experiment)

In the second experiment, using the plasma processing apparatus 10 having the transformer 100A as the transformer 100, a TiO ₂ film was formed on each of the six substrates by the film forming process DP1. In the step ST3 of the film forming process DP1, the first to sixth conditions described above are used. In the second experiment, the number of cycles performed in the film forming process DP1 was adjusted to a number between 164 times and 218 times so that the film thickness of the formed TiO ₂ film was 15 nm. The conditions of the film forming process DP1 in the second experiment are shown below.

<Conditions of Film Forming Process DP1 in Second Experiment>
Pressure of internal space 12s: 66.5 Pa
Carrier gas (argon gas) flow rate: 1000 sccm
Flow rate of reactive gas (oxygen gas): 500 sccm
Flow rate of precursor gas (TiCl ₄ gas) in step ST1: 24 sccm
Processing time of step ST2 in each cycle: 0.05 seconds Processing time of step ST3 in each cycle: 0.4 seconds

In the second experiment, wet etching using dilute hydrofluoric acid was applied to TiO ₂ films formed on a plurality of substrates, and the wet etching rate of each TiO ₂ film was determined. The results of the second experiment are shown in FIG. In the graph of FIG. 12, the horizontal axis indicates the self-bias potential Vdc in step ST3, and the vertical axis indicates the wet etching rate. As shown in FIG. 12, the wet etching rate had a negative correlation with the self-bias potential Vdc in step ST3. That is, it was confirmed that the wet etching rate becomes lower as the phase difference Δφ becomes smaller. Therefore, it was confirmed that the film density increases as the phase difference Δφ decreases.

  (Third experiment)

In the third experiment, using the plasma processing apparatus 10 having the transformer 100A as the transformer 100, a TiO ₂ film was formed on each of the eight substrates by the film forming process DP1. In step ST3 of the film forming process DP1 performed on four of the eight substrates, the phase difference Δφ is set to substantially zero and different ratios R are set so that a positive self-bias potential Vdc is generated. . On the other hand, in step ST3 of the film forming process DP1 performed on the other four substrates, the phase difference Δφ is set so as to generate the self-bias potential Vdc having a negative polarity, and different ratios R are set. In the third experiment, the number of cycles performed in the film forming process DP1 was adjusted to a number between 164 times and 218 times so that the film thickness of the formed TiO ₂ film would be 15 nm. The conditions of the film forming process DP1 in the third experiment are shown below.

<Conditions of film forming process DP1 in the third experiment>
Pressure of internal space 12s: 66.5 Pa
Carrier gas (argon gas) flow rate: 1000 sccm
Flow rate of reactive gas (oxygen gas): 500 sccm
Flow rate of precursor gas (TiCl ₄ gas) in step ST1: 24 sccm
Processing time of step ST2 in each cycle: 0.05 seconds Processing time of step ST3 in each cycle: 0.4 seconds

In the third experiment, the stress of the film formed on eight substrates was measured. The results of the third experiment are shown in FIG. In the graph of FIG. 13, the horizontal axis indicates the self-bias potential Vdc in step ST3, and the vertical axis indicates the stress of the film. In FIG. 13, the data included in the range where self bias potential Vdc is zero or more is data obtained by setting phase difference Δφ so that positive polarity self bias potential Vdc is generated in step ST3. . On the other hand, in FIG. 13, the data included in the range where self bias potential Vdc is smaller than zero (that is, having negative polarity) sets phase difference Δφ so that negative polarity self bias potential Vdc is generated in step ST3. It is the data acquired by doing. The ratio R and the self-bias potential Vdc have a positive correlation in the range where the self-bias potential Vdc is greater than or equal to zero. That is, as the ratio R increases, the self-bias potential Vdc increases. In the range where the self bias potential Vdc is smaller than zero, the ratio R and the absolute value of the self bias potential Vdc have a positive correlation. That is, as the ratio R increases, the absolute value of the negative self-bias potential Vdc increases. As shown in FIG. 13, when the phase difference Δφ is set so that a positive polarity self-bias potential Vdc is generated, it is confirmed that the stress of the film increases to the positive side as the ratio R increases. . In addition, when the phase difference Δφ was set so as to generate the negative self-bias potential Vdc, it was confirmed that the stress of the film increased to the positive side as the ratio R increased. Whether the film has a positive stress (tensile stress) or a negative stress (compressive stress) depends on the film type. The TiO ₂ film formed in the third experiment has negative stress. Therefore, when forming a TiO ₂ film, it was confirmed that the compressive stress of the film can be reduced by the increase of the ratio R. In other words, it was confirmed that the reduction of the ratio R can increase the compressive stress of the film. From this result, when the film to be formed is a film having positive stress, it is presumed that the tensile stress of the film can be increased by the increase of the ratio R.

  DESCRIPTION OF SYMBOLS 10 ... Plasma processing apparatus, 12 ... Chamber main body, 12s ... Internal space, 14 ... Support stand, 16 ... Lower electrode, 20 ... Upper electrode, 22 ... Gas supply part, 24 ... Exhaust apparatus, 26 ... High frequency supply part, 281, 282: Phase adjustment circuit.

Claims (12)

A film forming method performed using a plasma processing apparatus, comprising:
The plasma processing apparatus is
A chamber body,
A gas supply configured to supply a gas to an internal space provided in the chamber body;
A support, including a lower electrode, provided in the interior space and configured to support a substrate mounted thereon;
An upper electrode provided above the support;
A first high frequency supplied to the upper electrode, and a second high frequency having the same frequency as the first high frequency and supplied to the lower electrode, and the power of the first high frequency A high frequency supply configured to be able to adjust the ratio of the power of the second high frequency to
A phase adjustment circuit configured to adjust the phase of the voltage of the lower electrode relatively to the phase of the voltage of the upper electrode;
Equipped with
The film forming method is performed in a state where the substrate is placed on the support table,
Supplying a precursor gas including a precursor from the gas supply unit to the internal space;
Supplying a reactive gas from the gas supply unit to the internal space;
Generating a plasma of the reactive gas to enhance the reaction between the precursor and the reactive gas;
Including
In the step of generating plasma of the reactive gas, the ratio of the power of the second high frequency to the power of the first high frequency is adjusted, and the self-bias potential of the lower electrode is zero or positive. The phase adjustment circuit adjusts the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode to have a value,
Deposition method. A film forming method performed using a plasma processing apparatus, comprising:
The plasma processing apparatus is
A chamber body,
A gas supply configured to supply a gas to an internal space provided in the chamber body;
A support, including a lower electrode, provided in the interior space and configured to support a substrate mounted thereon;
An upper electrode provided above the support;
A first high frequency supplied to the upper electrode, and a second high frequency having the same frequency as the first high frequency and supplied to the lower electrode, and the power of the first high frequency A high frequency supply configured to be able to adjust the ratio of the power of the second high frequency to
A phase adjustment circuit configured to adjust the phase of the voltage of the lower electrode relatively to the phase of the voltage of the upper electrode;
Equipped with
The film forming method is performed in a state where the substrate is placed on the support table,
Supplying a precursor gas including a precursor from the gas supply unit to the internal space;
Supplying a reactive gas from the gas supply unit to the internal space;
Generating a plasma of the reactive gas to enhance the reaction between the precursor and the reactive gas;
Including
In the step of generating plasma of the reactive gas, the ratio of the power of the second high frequency to the power of the first high frequency is adjusted, and the self-bias potential of the lower electrode has a negative value. The phase adjustment circuit adjusts the phase of the voltage of the lower electrode relative to the phase of the voltage of the upper electrode,
Deposition method. The high frequency supply unit
High frequency power supply,
A primary coil electrically connected to the high frequency power supply, a first secondary coil electromagnetically coupled to the primary coil and electrically connected to the upper electrode, and electromagnetically coupled to the primary coil to the lower electrode It is a transformer which has the 2nd secondary coil electrically connected, It is output from the 2nd secondary coil to the electric power of the 1st high frequency outputted from the 1st secondary coil. The transformer configured to adjust the ratio of the second high frequency power to be
And further
In the step of generating a plasma of the reactive gas, a transformer adjusts the ratio of the power of the second high frequency power to the power of the first high frequency power,
The film forming method according to claim 1.   4. The method according to any one of claims 1 to 3, wherein the step of supplying precursor gas, the step of supplying reactive gas, and the step of generating plasma of reactive gas are performed simultaneously. Film forming method.   The process according to any one of the preceding claims, wherein during the step of supplying the reactive gas, the step of supplying the precursor gas and the step of generating a plasma of the reactive gas are alternately performed. The film-forming method as described in a term. The precursor gas is a titanium-containing gas,
The reactive gas is an oxygen-containing gas,
The film-forming method as described in any one of Claims 1-5.   The film forming method according to claim 6, wherein the titanium-containing gas is a titanium halide gas.   The film forming method according to claim 7, wherein the titanium halide gas is titanium tetrachloride gas.   The film forming method according to any one of claims 6 to 8, wherein the oxygen-containing gas is oxygen gas. A film forming method performed using a plasma processing apparatus, comprising:
The plasma processing apparatus is
A chamber body,
A gas supply configured to supply a gas to an internal space provided in the chamber body;
A support, including a lower electrode, provided in the interior space and configured to support a substrate mounted thereon;
An upper electrode provided above the support;
A first high frequency supplied to the upper electrode, and a second high frequency having the same frequency as the first high frequency and supplied to the lower electrode, and the power of the first high frequency A high frequency supply configured to be able to adjust the ratio of the power of the second high frequency to
A phase adjustment circuit configured to adjust the phase of the voltage of the lower electrode relatively to the phase of the voltage of the upper electrode;
Equipped with
The film forming method is
A step of performing a film forming process under initial conditions in order to form a first film on a first substrate placed on the support table, the film forming process comprising
Supplying a precursor gas including a precursor from the gas supply unit to the internal space;
Supplying a reactive gas from the gas supply unit to the internal space;
Generating a plasma of the reactive gas to enhance the reaction between the precursor and the reactive gas;
And the initial condition includes an initial value of a ratio of the power of the second high frequency to the power of the first high frequency and a voltage of the upper electrode in the step of generating plasma of the reactive gas. The step of including an initial value of a phase difference of voltages of the lower electrode;
Evaluating the first film, wherein an evaluation result including at least a stress of the first film is generated;
Determining a processing condition of the film forming process based on the evaluation result;
Performing the film forming process under the process conditions to form a second film on a second substrate placed on the support table;
Including
The processing conditions include the ratio of the power of the second high frequency to the power of the first high frequency in the step of generating plasma of the reactive gas, and the ratio of the voltage of the lower electrode to the voltage of the upper electrode. Including the difference,
In the step of determining the processing condition, the ratio in the processing condition is set based on the evaluation result.
Deposition method.   The polarity of the self-bias potential of the lower electrode at the time of execution of the film forming process under the processing conditions is the polarity of the self-bias potential of the lower electrode at the time of execution of the film forming process under the initial conditions. The film forming method according to claim 10, wherein The initial value of the ratio included in the initial condition to reduce the compressive stress of the second film relative to the stress of the first film or to increase the tensile stress of the second film The ratio included in the process condition is increased,
The initial value of the ratio included in the initial condition to reduce the tensile stress of the second film relative to the stress of the first film or to increase the compressive stress of the second film The ratio included in the processing conditions is reduced,
The film forming method according to claim 10.

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