Plasma processing apparatus and plasma processing method

Abstract

To provide a plasma processing apparatus capable of generating plasma by supplying a high-frequency power to an electrode in a plasma generation part, and performing uniform plasma processing when the plasma is introduced to a substrate for plasma processing, and provide a plasma processing method.SOLUTION: A plasma processing apparatus includes: a processing container having a processing space where a substrate is arranged; a plasma generation part which has a first electrode and a second electrode provided opposite each other and constructed as parallel plate electrodes, and in which a plas generation space is formed between them; a high-frequency power source that forms a high-frequency electric field between the first electrode and the second electrode; a gas supply part that supplies processing gas for generating plasma in the plasma generation space; a plasma introduction part that introduces the plasma generated in the plasma generation space to the processing space; and a heat conduction member that is provided between the first electrode and the second electrode in a manner to thermally connect to them, and is formed of an insulation body. By the plasma introduced into the processing space, the plasma processing is executed on the substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a plasma processing apparatus and a plasma processing method. [Background technology]

[0002] In the manufacturing process of semiconductor devices, plasma processing apparatuses are used to perform plasma processing on semiconductor wafers, which are substrates. Patent Document 1 discloses a remote-type plasma processing apparatus that divides a processing vessel into a reaction chamber in which an object to be processed is placed and a plasma generation chamber, applies high-frequency power to an upper electrode to generate plasma in the plasma generation chamber, and introduces active species in the plasma into the reaction chamber for plasma processing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-155387 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a plasma processing apparatus and a plasma processing method that can perform uniform plasma processing when generating plasma by supplying high-frequency power to an electrode in a plasma generating unit and directing the plasma to a substrate for plasma processing. [Means for solving the problem]

[0005] A plasma processing apparatus according to one aspect of the present disclosure includes a processing chamber having a processing space in which a substrate is placed, a plasma generation unit having first and second electrodes arranged opposite each other and configured as parallel plate electrodes, whereby a plasma generation space is formed between the first and second electrodes, a high-frequency power supply unit that forms a high-frequency electric field between the first and second electrodes, a gas supply unit that supplies a processing gas for generating plasma into the plasma generation space, a plasma introduction unit that introduces the plasma generated in the plasma generation space into the processing space, and a heat transfer member made of an insulator that is arranged between the first and second electrodes to thermally connect them, the heat transfer member is provided so as to suppress the generation of parasitic capacitance, and is fitted into recesses formed in the first electrode and the second electrode; The substrate is subjected to plasma processing by the plasma introduced into the processing space. [Effects of the Invention]

[0006] According to the present disclosure, a plasma processing apparatus and a plasma processing method are provided that can perform uniform plasma processing when generating plasma by supplying high-frequency power to an electrode in a plasma generating unit and directing the plasma to a substrate for plasma processing. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view schematically showing a plasma processing apparatus according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing in detail a main part of the plasma processing apparatus of FIG. [Figure 3] FIG. 10 is a cross-sectional view showing a main part of a plasma processing apparatus according to a second embodiment. [Figure 4] FIG. 10 is a cross-sectional view showing a main part of a plasma processing apparatus according to a third embodiment. [Figure 5] FIG. 10 is a cross-sectional view showing a main part of a plasma processing apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the accompanying drawings. First Embodiment First, the first embodiment will be described. FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to a first embodiment, and FIG. 2 is a cross-sectional view showing the main parts thereof in detail.

[0009] The plasma processing apparatus 100 of this embodiment performs plasma processing on a substrate W. The plasma processing is not particularly limited, but examples thereof include film formation processing such as CVD and ALD.

[0010] The plasma processing apparatus 100 has a processing vessel 10 that is substantially cylindrical and made of metal, such as aluminum whose surface has been anodized. The processing vessel 10 is divided into a lower space 11 and an upper space 12, with the lower space 11 functioning as the processing space. The plasma processing apparatus 100 also has a plasma generation unit 30.

[0011] A stage 20 on which the substrate W is placed is provided in the lower space 11. The stage 20 is supported by a support member 21. The support member 21 extends downward through the bottom wall of the processing vessel 10 and can be raised and lowered by a lifting mechanism (not shown). A sealing mechanism (not shown) is provided between the support member 21 and the bottom wall of the processing vessel 10. The stage 20 and the support member 21 are made of, for example, metal, such as aluminum whose surface is anodized. The stage 20 is provided with lifting pins (not shown) that rise and fall relative to the surface of the stage 20 to transport the substrate W. The stage 20 may also be provided with a temperature control mechanism such as an electrostatic chuck for electrostatically attracting the substrate W and a heater.

[0012] An exhaust port 22 is formed in the bottom of the processing vessel 10, and an exhaust pipe 23 is connected to the exhaust port 22. An exhaust device 24 including a vacuum pump, a pressure control valve, etc. is connected to the exhaust pipe 23. By operating the exhaust device 24, the lower space 11, which is the processing space, is evacuated and the lower space 11 is maintained at a predetermined vacuum level. In addition, a load / unload port 25 for loading / unloading the substrate W is formed in the sidewall of the processing vessel 10, and the load / unload port 25 can be opened and closed by a gate valve 26.

[0013] The plasma generation part 30 is provided in the upper space 12, and is configured as a shower head, having a lower shower plate 41 as a lower electrode, an upper shower plate 42 as an upper electrode, and a sealing plate 43 provided on the upper shower plate 42. The lower shower plate 41 as the lower electrode and the upper shower plate 42 as the upper electrode configure parallel plate electrodes, and the space between them becomes a plasma generation space 45.

[0014] The lower shower plate 41 and the upper shower plate 42 are made of a metal such as aluminum alloy, titanium, or stainless steel, are disk-shaped, and are stacked at intervals via an insulating ring 44 provided on the outer periphery. The insulating ring 44 is made of an insulator such as alumina, quartz, yttria, or Teflon (registered trademark), and the spaces between the insulating ring 44 and the lower shower plate 41 and between the insulating ring 44 and the upper shower plate 42 are sealed with sealing members such as seal rings (O-rings).

[0015] A plurality of gas holes 41a penetrating vertically are formed in lower shower plate 41, and a plurality of gas holes 42a penetrating vertically are formed in upper shower plate 42. The distance between lower shower plate 41 and upper shower plate 42, i.e., the distance between the parallel plate electrodes (electrode distance), can be set so as to obtain a quasi-TEM wave according to the frequency, as will be described later.

[0016] The lower shower plate 41 has the function of dividing the interior of the processing vessel 10 into a lower space 11 and an upper space 12, and is attached to the side wall of the processing vessel 10. The gap between the lower surface of the lower shower plate 41 and the side wall of the processing vessel 10 is sealed with a sealing member such as a seal ring (O-ring), so that the interior of the lower space 11, which is the processing space, is kept airtight.

[0017] The sealing plate 43 is made of a metal such as aluminum alloy, titanium, or stainless steel, and functions to seal the upper shower plate 42 and separate the air atmosphere from the vacuum atmosphere. The outer edge of the sealing plate 43 protrudes downward, and a sealing member such as a seal ring (O-ring) seals the gap between the outer edge of the sealing plate 43 and the upper shower plate 42. The space between the sealing plate 43 and the upper shower plate 42 forms a gas diffusion space 46.

[0018] The plasma processing apparatus 100 further includes a high-frequency power supply 50 and a gas supply unit 60 .

[0019] The high-frequency power supply 50 forms a high-frequency electric field between the lower shower plate 41, which serves as the lower electrode, and the upper shower plate 42, which serves as the upper electrode. A power supply line 52 extending from the high-frequency power supply 50 is connected to the sealing plate 43 via a high-frequency introduction unit 27 provided in the ceiling wall 10a of the processing chamber 10. A matching unit 51 is interposed in the power supply line 52. The high-frequency power from the high-frequency power supply 50 is applied to the upper shower plate 42, which serves as the upper electrode, via the sealing plate 43, and a high-frequency electric field is formed in a plasma generation space 45 between the lower shower plate 41 and the upper shower plate 42, which form parallel plate electrodes. The frequency of the high-frequency power supply 50 is not particularly limited as long as it can generate plasma, but is preferably in the VHF to UHF band (a range of several hundred kHz to several hundred MHz). The space around the power supply line 52 between the ceiling wall of the processing chamber 10 and the sealing plate 43 serves as a high-frequency propagation unit 53.

[0020] The gas supply unit 60 supplies a process gas for plasma processing, an inert gas for pressure adjustment and purging, etc. When the plasma processing is a film formation process such as CVD or ALD, a film-forming source gas and a reactive gas are used as the process gas. When a film is formed by a thermal decomposition reaction of a film-forming source gas, only the film-forming source gas may be supplied as the process gas. A gas supply pipe 61 extends from the gas supply unit 60 and is connected to a gas introduction path 62. The gas introduction path 62 is connected to the gas diffusion space 46 via the ceiling wall 10a of the processing chamber 10, a spacer 63 provided between the ceiling wall 10a and the sealing plate 43, and the sealing plate 43. Therefore, the process gas supplied from the gas supply unit 60 reaches the plasma generation space 45 via the gas supply pipe 61, the gas introduction path 62, the gas diffusion space 46, and the gas holes 42a. Then, a capacitively coupled plasma is generated in the plasma generation space 45 by a high-frequency electric field formed between the upper shower plate 42 and the lower shower plate 41. The plasma generated in the plasma generation space 45 is composed of active species and charged particles, and only the active species or the active species and the charged particles are introduced from the gas hole 41a into the processing space, the lower space 11. In other words, the gas hole 41a functions as a plasma introduction part that introduces only the active species in the plasma generation space 45 or the active species and the charged particles into the processing space, the lower space 11.

[0021] A lower heat transfer member 71 made of an insulator is provided between the upper shower plate 42 and the lower shower plate 41 so as to thermally connect them. In the example of FIG. 1, a plurality of (for example, six) lower heat transfer members 71 are provided. The plurality of lower heat transfer members 71 can be preferably provided at positions symmetrical about the axis. For example, one lower heat transfer member 71 may be provided in the center. The lower heat transfer member 71 has the function of dissipating heat exerted from the plasma to the lower shower plate 41 by heat transfer.

[0022] Because capacitively coupled plasma is generated between the lower shower plate 41 and the upper shower plate 42, the lower heat transfer member 71 must be an insulator. The insulator constituting the lower heat transfer member 71 can be an insulator with high thermal conductivity so as to effectively dissipate heat through heat transfer. Examples of such insulators with high thermal conductivity include aluminum nitride (AlN), alumina (Al2O3), silicon carbide (SiC), quartz glass, and yttria (Y2O3). Among these, AlN, which has particularly high thermal conductivity, is particularly suitable. The insulator constituting the lower heat transfer member 71 may be a resin, such as polyimide, polyphenylene sulfide, or polyether ether ketone. The thermal conductivity of the lower heat transfer member 71 can be selected according to the operating temperature. For example, a material with a thermal conductivity of 100 W / K·m or more at an operating temperature range of 20 to 200°C is preferred. Such high thermal conductivity can be achieved by the aforementioned AlN.

[0023] 2, the lower heat transfer member 71 is fitted into a recess 48 formed in the upper surface of the lower shower plate 41 and a recess 49 formed in the lower surface of the upper shower plate 42. The lower heat transfer member 71 is fastened to the lower shower plate 41 by screwing it from above the upper shower plate 72 via the lower heat transfer member 71 using screws 74 made of an insulator such as AlN, Al2O3, or SiC.

[0024] Between the upper shower plate 42 and the sealing plate 43, a metallic upper heat transfer member 72 is provided so as to thermally connect them. In the example of FIG. 1, a plurality of (for example, six) upper heat transfer members 72 are provided. The plurality of upper heat transfer members 72 are preferably provided at positions symmetrical about the axis. For example, one upper heat transfer member 72 may be provided in the center. The upper heat transfer member 72 has the function of guiding heat transferred to the upper shower plate 42 to the sealing plate 43. The space above the sealing plate 43 is an atmospheric air, and the heat transferred from the upper heat transfer member 72 to the sealing plate 43 is removed by thermal convection or the like.

[0025] The upper heat transfer member 72 is made of, for example, the same material as the upper shower plate 42 and is configured integrally with the upper shower plate 42. As shown in detail in Fig. 2, the upper heat transfer member 72 and the sealing plate 43 are fastened together with metal screws 75, and the space between the upper heat transfer member 72 and the sealing member 43 may be sealed with a sealing member 76 such as a seal ring (O-ring). Note that the upper heat transfer member 72 may be separate from the upper shower plate 42.

[0026] The plasma processing apparatus 100 further includes a control unit 80. The control unit 80 controls components of the plasma processing apparatus 100, such as the exhaust unit 24, the high-frequency power supply 50, and valves of the gas supply unit 60. The control unit 80 includes a main control unit having a CPU, an input device, an output device, a display device, and a storage device. The plasma processing apparatus 100 is controlled based on a processing recipe stored in a storage medium of the storage device.

[0027] Next, a processing operation performed by the plasma processing apparatus 100 configured as above will be described. First, the substrate W is carried into the lower space 11, which is the processing space of the processing vessel 10, and placed on the stage 20. Next, an inert gas is supplied from the gas supply unit 60 to the lower space 11 via the plasma generation unit 30 constituting a shower head, while the lower space 11 is evacuated and pressure-regulated by the exhaust device 24 to create a desired vacuum atmosphere.

[0028] In this state, a processing gas is supplied from the gas supply unit 60 to the plasma generation unit 30 constituting the shower head, and high frequency power is applied from the high frequency power supply 50 via the sealing plate 43 to the upper shower plate 42 which is the upper electrode.

[0029] Specifically, by applying high-frequency power to the upper shower plate 42, a high-frequency electric field is formed in a plasma generation space 45 between the lower shower plate 41, which serves as the lower electrode, and the upper shower plate 42, which serves as the upper electrode. In addition, by supplying a processing gas to the plasma generation unit 30, the processing gas passes from the gas diffusion space 46 through the gas holes 42a and reaches the plasma generation space 45, and the high-frequency electric field generates a capacitively coupled plasma in the plasma generation space 45. The generated plasma is composed of active species and charged particles, and either only the active species or both the active species and the charged particles are introduced from the gas holes 41a, which function as the plasma introduction unit, into the lower space 11, which serves as the processing space, and then supplied to the substrate W, where the substrate W is processed.

[0030] At this time, when plasma is generated in the plasma generation space 45, ions and electrons in the plasma are incident on the upper surface of the lower shower plate 41 and the lower surface of the upper shower plate 42. The incident ions and electrons have kinetic energy, and impart heat to these surfaces when they collide with them. Furthermore, when the substrate W on the stage 20 is heated, heat is also imparted to the lower shower plate 41 and the upper shower plate 42 from the substrate W.

[0031] With the advancement of semiconductor manufacturing technology, there is a demand for higher performance plasma processing apparatuses. In particular, in plasma processing apparatuses for film formation, such as CVD and ALD, there is a demand for increased productivity by increasing the density of activated species in the gas phase and the plasma density. In a remote-type plasma processing apparatus such as the present embodiment, when high power is input to improve productivity, the amount of heat applied to the lower surface of the upper shower plate 42 and the upper surface of the lower shower plate 41 increases in proportion to the input power. As a result, the temperatures of the upper surface of the lower shower plate 41 and the lower surface of the upper shower plate 42 increase. Without the lower heat transfer member 71, the upper shower plate 42 may warp downward and the lower shower plate 41 may warp upward due to the difference in thermal expansion. If the lower shower plate 41 (the lower electrode) and the upper shower plate 42 (the upper electrode) warp in this way, the distance between them (electrode spacing) cannot be maintained constant, resulting in non-uniform plasma generation.

[0032] In particular, when the frequency of the high frequency power is increased to, for example, 180 MHz or higher in order to increase the density of activated species and plasma density and thereby improve the efficiency of plasma processing, the electrode spacing at which the quasi-TEM waves necessary for generating uniform plasma are obtained becomes smaller, for example, 2 to 3 mm, as will be described later. When the electrode spacing becomes smaller in this manner, the rate of variation in the electrode spacing due to warping occurring in lower shower plate 41, which is the lower electrode, and upper shower plate 42, which is the upper electrode, becomes relatively larger, and this has a significant impact on the uniformity of the plasma.

[0033] In order to suppress such electrode warpage, it is effective to effectively remove heat from the lower electrode and the upper electrode, and for this purpose, it is considered effective to make the lower electrode and the upper electrode thicker to reduce their radial thermal resistance. It is also considered effective to provide a coolant flow path inside the electrodes and remove heat with the coolant. In either case, conventional common knowledge has dictated that in order to remove heat effectively, the lower electrode and the upper electrode must be thicker.

[0034] However, in a remote-type plasma processing apparatus, activated species and charged particles in the plasma generated in the plasma generation space are discharged into the processing space through gas holes in the lower shower plate, which serves as the lower electrode. If the lower electrode is thick, the gas holes become long, which makes it easier for the activated species and charged particles to be deactivated. Therefore, it is difficult to improve productivity even when a large current is applied.

[0035] Therefore, in this embodiment, a lower heat transfer member 71 made of an insulator is provided between the lower shower plate 41, which is the lower electrode, and the upper shower plate 42, which is the upper electrode, so as to thermally connect them. This allows heat to be released via the lower heat transfer member 71 while maintaining insulation between the lower shower plate 41 and the upper shower plate 42.

[0036] Specifically, the heat that has flowed into the lower shower plate 41 is transferred to the upper shower plate 42 via the lower heat transfer member 71. Then, the heat that has flowed into the upper shower plate 42 is transferred to the sealing plate 43 via the upper heat transfer member 72. Since the space above the sealing plate 43 is an atmospheric air, the heat that has flowed into the sealing plate 43 is removed by thermal convection or the like.

[0037] Since the lower heat transfer member 71 is provided to remove heat in this manner, heat can be effectively removed from the lower shower plate 41 and the upper shower plate 42 even when a large amount of power is applied. This prevents warping of the lower shower plate 41 and the upper shower plate 42, which are the lower and upper electrodes. This keeps the distance (electrode spacing) between the lower shower plate 41 and the upper shower plate 42 as constant as possible, suppressing plasma non-uniformity and enabling uniform plasma processing on the substrate W. In particular, when the frequency of the high-frequency power is high, it is advantageous to reduce the electrode spacing as described above. However, even when the influence of variations in the electrode spacing is significant, the lower heat transfer member 71 effectively dissipates heat, suppressing variations in the electrode spacing and enabling uniform plasma processing. Since heat can be effectively removed from the lower shower plate 41 and the upper shower plate 42, warping can be prevented even when the lower shower plate 41 and the upper shower plate 42 are thin, and deactivation of activated species passing through the gas holes 41 a can also be suppressed.

[0038] Furthermore, even if the temperature of the lower shower plate 41 and the upper shower plate 42 rises due to the incidence of ions and electrons in the plasma in the plasma generation space 45, causing them to warp slightly, the warping acts in a direction that sandwiches the lower heat transfer member 71. Therefore, the lower heat transfer member 71 and the lower shower plate 41 and the upper shower plate 42 come into close contact with each other, reducing the contact thermal resistance between them and dissipating heat more effectively, preventing further warping. Furthermore, the lower heat transfer member 71 can physically maintain a constant distance between the lower shower plate 41 and the upper shower plate 42. Therefore, even if a force acts on the lower shower plate 41 and the upper shower plate 42 to deform them, the lower heat transfer member 71 prevents the distance between them from changing, making it easier to generate uniform and stable plasma in the plasma generation space 45.

[0039] Furthermore, the effect of dissipating heat through heat transfer can be enhanced by using an insulator with high thermal conductivity, such as AlN, Al2O3, SiC, quartz glass, or Y2O3, for the lower heat transfer member 71. The thermal conductivity of the insulator constituting the lower heat transfer member 71 can be selected according to the operating temperature, and in particular, a material with high thermal conductivity, for example, 100 W / K·m or more at an operating temperature in the range of 20 to 200°C, is preferred. AlN is a suitable insulator with such high thermal conductivity.

[0040] There are no particular limitations on the number and arrangement of the lower heat transfer members 71, and they may be one or more, as long as they are set taking into consideration the uniformity of the plasma and the heat transfer effect. When there are multiple lower heat transfer members 71, they can be arranged in axially symmetrical positions to allow heat to be dissipated uniformly.

[0041] Next, the distance between the lower shower plate 41 and the upper shower plate 42 that constitute the parallel plate electrodes will be described. From the viewpoint of generating uniform plasma, it is preferable to propagate the high frequency power as a quasi-TEM wave. If modes other than the quasi-TEM wave are generated, the plasma uniformity will deteriorate. In order to propagate the high frequency power as a quasi-TEM wave, the distance (electrode distance) d between the lower shower plate 41 and the upper shower plate 42, which constitute the parallel plate electrodes, must be smaller than the plasma skin depth. If the electrode distance d is larger than the plasma skin depth, modes other than the quasi-TEM wave will be generated. Furthermore, in order to obtain higher plasma uniformity, it is effective for the wavelength of the quasi-TEM wave to be long, and from this viewpoint, it is preferable to make the electrode distance d sufficiently smaller than the plasma skin depth.

[0042] This point will be explained in more detail. The wavelength λ of the quasi-TEM wave is approximately expressed by the following equation (1) (P. Chabert, J.-L. Raimbault, J.-M. Rax, and A. Perret, “Suppression of the standing wave effect in high frequency capacitive discharges using a shaped electrode and dielectric lens: Self-consistent approach,” PHYSICS OF PLASMAS, 11, 8(2004). ). λ = 40λ0V0 1 / 10 d -1 / 2 f -2 / 5 (1) Here, λ0 is the wavelength in vacuum (m), V0 is the amplitude of the high frequency (V), and f is the frequency (Hz). In the case of a circular electrode, a standing wave with the center of the electrode as the antinode is formed between the electrodes. The voltage V(r) between the electrodes at the radial position r is expressed by the following equation (2). V(r) = V0J0(kr) (2) Here, J0 is the Bessel function of the first kind of order 0, and k is the wave number. When the radius of the substrate is R, for example, if 0.8V(0) < V(R), from the above equation (2), λ > 9.8R can be obtained. Substituting this into equation (1), the following equation (3) can be obtained. d < 17(λ0 / R) 2 V0 1 / 5 f -4 / 5 (3) From equation (3), it can be derived that the higher the frequency, the smaller the electrode gap d needs to be set. For example, when f = 100 MHz, it is derived that it is preferable to make the electrode gap d smaller than 7 mm in order to obtain a sufficiently uniform plasma.

[0043] <Second Embodiment> Next, the second embodiment will be described. FIG. 3 is a cross-sectional view showing the main part of the plasma processing apparatus according to the second embodiment.

[0044] 3, in this embodiment, the diameter of gas holes 41b in the peripheral portion of the lower heat transfer member 71 of the lower shower plate 41 is formed to be larger than the diameter of other normal gas holes 41a. The other configuration is the same as in the first embodiment, so a description thereof will be omitted.

[0045] When an insulator is present in the plasma generation space, charged particles in the plasma disappear around the insulator. Therefore, the plasma density around the insulator in the plasma generation space is lower than in other areas. Therefore, if the gas holes have a uniform diameter, the amount of activated species released from the gas holes around the insulator will be less than the amount of activated species released from other gas holes, which may result in insufficient uniformity in the distribution of activated species in the lower space 11, which is the processing space. In this case, uniform plasma processing of the substrate W cannot be performed.

[0046] Therefore, in this embodiment, the diameter of the gas holes 41b in the peripheral portion of the lower heat transfer member 71, which is an insulator, is made larger than the other gas holes 41a in the lower shower plate 41. This suppresses deactivation of the active species in the gas holes 41b, compensates for the decrease in the amount of active species released from the gas holes in the peripheral portion of the lower heat transfer member 71, and makes the distribution of the active species in the lower space 11 uniform, thereby enabling uniform plasma processing of the substrate W.

[0047] <Third embodiment> Next, a third embodiment will be described. FIG. 4 is a cross-sectional view showing a main part of a plasma processing apparatus according to the third embodiment.

[0048] In this embodiment, as shown in Fig. 4, the upper shower plate 42 has a gas flow path 91 therein. A plurality of gas holes 42b extending from the gas flow path 91 and opening into the plasma generation space 45 are formed in the lower part of the upper shower plate 42. Screws 77 made of an insulator and having holes 78 penetrating in the axial direction are threaded from above the upper shower plate 42 through the lower heat transfer member 71 and into the lower shower plate 41, thereby fastening the lower heat transfer member 71. Gas holes 41c communicating with the holes 78 of the screws 77 are formed in the lower plate 41. The upper heat transfer member 72 is fastened with metal screws 92 having holes 93 penetrating in the axial direction. Gas holes 72a opening into the gas flow path 91 are formed in the upper heat transfer member 72.

[0049] In this embodiment, the processing gas that is to be converted into plasma can be supplied to the plasma generation space 45 via the hole 93, the gas hole 72a, the gas flow path 91, and the gas hole 42b. On the other hand, the processing gas that is not to be converted into plasma can be supplied to the lower space 11, which is the processing space, via the gas flow path 62, the gas diffusion space 46, the hole 78, and the gas hole 41c without passing through the plasma generation space 45.

[0050] For example, in a film formation process such as CVD or ALD, there are cases where it is not desirable to convert the raw material gas into plasma, but it is desirable to convert the reactive gas into plasma. In such a case, according to this embodiment, the reactive gas is excited into plasma in the plasma generation space 45, and the raw material gas can be supplied to the lower space 11 without passing through the plasma generation space 45.

[0051] In the above description, an example is shown in which the gas to be converted into plasma is supplied to the gas flow path 91 communicating with the plasma generation space 45 via the gas hole 72a provided in the upper heat transfer member 72, but this is not limited to this.

[0052] <Fourth embodiment> Next, a fourth embodiment will be described. This embodiment defines a preferred range of the shape factor for the lower heat transfer member 71. Fig. 5 is a cross-sectional view showing a main part of a plasma processing apparatus according to a fourth embodiment. For convenience, Fig. 5 is based on Fig. 4 of the third embodiment, but this embodiment would be the same even if Figs. 1 to 3 of the first or second embodiment were used as the basis.

[0053] The lower heat transfer member 71 fits into the recess 48 provided in the lower shower plate 41 and the recess 49 provided in the upper shower plate 42, and the length of the lower heat transfer member 71 is longer than the distance (the distance between the electrodes) between the lower shower plate 41 and the upper shower plate 42. A gap g is formed between the side surface of the lower heat transfer member 71 and the side surfaces of the recess 48 and the recess 49. Since the length of the lower heat transfer member 71 is longer than the distance between the electrodes and the gap g is provided in the fitting portion, an increase in parasitic capacitance due to the installation of the lower heat transfer member 71 made of an insulator can be suppressed, and deterioration of the plasma distribution in the plasma generation space 45 due to biased high-frequency current can be easily avoided.

[0054] It is desirable that the gap g between the side surface of the lower heat transfer member 71 and the side surfaces of the recesses 48 and 49 be smaller than the plasma sheath thickness (0.1 to 1 mm). That is, if plasma gets into the gap g, the plasma distribution may deteriorate, so the gap g is made smaller than the sheath thickness to suppress the intrusion of plasma into the gap g.

[0055] 5, when the fitting depth of the lower heat transfer member 71 to the lower shower plate 41 and the upper shower plate 42 is h and the distance (inter-electrode distance) between the lower shower plate 41 and the upper shower plate 42 is d, it is preferable that h>0.1d. By satisfying this relationship, the effect of reducing parasitic capacitance due to the provision of the fitting portion can be further enhanced.

[0056] Furthermore, when the diameter of the lower heat transfer member 71 is p, it is preferable that h<3p. If the depth h of the fitting portion is greater than 3p, the parasitic capacitance will hardly change even if the depth h of the fitting portion is changed, but the thermal resistance of the lower heat transfer member 71 will increase.

[0057] <Other applications> Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0058] For example, in the above embodiment, the lower shower plate serves as the lower electrode, the upper shower plate serves as the upper electrode, and the process gas is supplied to the plasma generation space in a shower-like manner, and activated species in the plasma are introduced into the processing space in a shower-like manner. However, the present invention is not limited to the above embodiment, as long as the plasma processing apparatus is a remote-type plasma processing apparatus in which plasma is excited between parallel plate electrodes and introduced into the processing space. Furthermore, in the above embodiment, a sealing plate is provided above the upper shower plate via a gas diffusion space, and an upper heat transfer member is provided between the upper shower plate and the sealing plate to transfer heat from the upper shower plate to the upper heat transfer member. However, the present invention is not limited to this. Furthermore, although the plasma processing has been described using film formation processes such as CVD and ALD as examples, the present invention is not limited to these, and other plasma processing processes such as plasma etching may also be used. [Explanation of symbols]

[0059] 10. Processing container 11: Lower space (processing space) 20 Stage 24;Exhaust system 30: Plasma generation unit 41: Lower shower plate (lower electrode) 42: Upper shower plate (upper electrode) 50;High frequency power supply 60: Gas supply section 71: Lower heat transfer member (heat transfer member) 72: Upper heat transfer member 100: Plasma treatment device W; substrate

Claims

1. a processing vessel having a processing space in which a substrate is placed; a plasma generating section having a first electrode and a second electrode configured as parallel plate electrodes, the first electrode and the second electrode being opposed to each other, and a plasma generating space being formed between the first electrode and the second electrode; a high frequency power supply means for forming a high frequency electric field between the first electrode and the second electrode; a gas supply unit that supplies a processing gas for generating plasma into the plasma generating space; a plasma introduction part that introduces the plasma generated in the plasma generation space into the processing space; a heat transfer member made of an insulator and provided between the first electrode and the second electrode so as to thermally connect them; and the heat transfer member is provided so as to suppress the generation of parasitic capacitance, and is fitted into recesses formed in the first electrode and the second electrode; The plasma processing apparatus performs plasma processing on the substrate by using plasma introduced into the processing space.

2. The plasma processing apparatus according to claim 1 , wherein a gap between the side surface of the heat transfer member and the recess is smaller than a sheath thickness of the plasma.

3. 3. The plasma processing apparatus according to claim 1, wherein, when the depth of the recess is h and the distance between the first electrode and the second electrode is d, h>0.1d is satisfied.

4. 4. The plasma processing apparatus according to claim 1, wherein h<3p is satisfied, where h is a depth of the recess and p is a diameter of the heat transfer member.

5. 5. The plasma processing apparatus according to claim 1, wherein a distance between the first electrode and the second electrode is set to be smaller than a plasma skin depth so that the high frequency power is propagated as a quasi-TEM wave.

6. 6. The plasma processing apparatus according to claim 5, wherein a distance d between the first electrode and the second electrode is set to satisfy the following formula: d<17(λ ０ / R) ２ V ０ １／５ f －４／５ where λ ０ is the wavelength in vacuum (m), V ０ is the amplitude of the high frequency wave (V), f is the frequency (Hz), and R is the radius of the substrate.

7. A processing vessel having a processing space in which a substrate is placed; a plasma generating section having a first electrode and a second electrode configured as parallel plate electrodes, the first electrode and the second electrode being opposed to each other, and a plasma generating space being formed between the first electrode and the second electrode; a high frequency power supply means for forming a high frequency electric field between the first electrode and the second electrode; a gas supply unit that supplies a processing gas for generating plasma into the plasma generating space; a plasma introduction part that introduces the plasma generated in the plasma generation space into the processing space; a heat transfer member made of an insulator and provided between the first electrode and the second electrode so as to thermally connect them; and a distance between the first electrode and the second electrode is set to be smaller than a plasma skin depth so that the high frequency power is propagated as a quasi-TEM wave; The plasma processing apparatus performs plasma processing on the substrate by using plasma introduced into the processing space.

8. A plasma processing apparatus as described in Claim 7, wherein the distance d between the first electrode and the second electrode is set to satisfy the following formula. d<17(λ 0 / R) 2 V 0 1 / 5 f -4 / 5 where λ 0 is the wavelength in vacuum (m), V 0 is the amplitude of the high frequency wave (V), f is the frequency (Hz), and R is the radius of the substrate.

9. The plasma processing apparatus according to claim 1 , wherein the heat transfer member is provided so as to maintain a constant distance between the first electrode and the second electrode.

10. The plasma processing apparatus according to claim 1 , wherein a plurality of the heat transfer members are provided, and the plurality of heat transfer members are provided at positions symmetrical with respect to an axis.

11. 11. The plasma processing apparatus according to claim 1, wherein the heat transfer member is made of a material selected from the group consisting of aluminum nitride, alumina, silicon carbide, quartz glass, and yttria.

12. The plasma processing apparatus according to claim 1 , wherein the thermal conductivity of the heat transfer member is selected depending on an operating temperature.

13. 13. The plasma processing apparatus according to claim 12, wherein the heat transfer member has a thermal conductivity of 100 W / K·m or more in an operating temperature range of 20 to 200°C.

14. The plasma processing apparatus according to claim 13 , wherein the heat transfer member is made of aluminum nitride.

15. the plasma generating unit constitutes a shower head, the first electrode is a lower shower plate having a plurality of first gas holes, the second electrode is an upper shower plate having a plurality of second gas holes, the first gas holes function as the plasma introducing unit, and the plasma generating unit further comprises a sealing member sealing the upper shower plate so as to form a gas diffusion space between the upper shower plate and the sealing member, and a second heat transfer member provided between the upper shower plate and the sealing member so as to thermally connect them, a processing gas for generating plasma is supplied from the gas supply unit to the plasma generation space through the gas diffusion space and the second gas hole; 15. The plasma processing apparatus according to claim 1, wherein the plasma generated in the plasma generating space is introduced into the processing space through the first gas hole serving as the plasma introducing portion.

16. The plasma processing apparatus of claim 15 , wherein among the plurality of first gas holes, those present in a peripheral portion of the heat transfer member are formed larger than the other first gas holes.

17. 17. The plasma processing apparatus according to claim 15, wherein the heat transfer member has through holes and is fastened to the lower shower plate and the upper shower plate with screws made of an insulator, a part of the processing gas passes through the through holes of the screws and is supplied to the processing space without passing through the plasma generation space, and the rest of the processing gas is converted into plasma in the plasma generation space and then introduced into the processing space through the first gas hole as the plasma introduction part.

18. 18. The plasma processing apparatus according to claim 17, wherein the plasma processing is a film formation processing in which a film is formed on a substrate by a reaction between a film formation source gas and a reactive gas, and a part of the processing gas supplied to the processing space without passing through the plasma generation space is the film formation source gas, and the remaining part of the processing gas that is turned into plasma in the plasma generation space is the reactive gas.

19. 19. The plasma processing apparatus according to claim 1, wherein the frequency of the high frequency power supplied by said high frequency power supply means is in the VHF to UHF band.

20. A plasma processing method for performing plasma processing on a substrate using a plasma processing apparatus, comprising: The plasma processing apparatus includes a processing vessel having a processing space in which a substrate is placed, a plasma generating unit having first and second electrodes arranged opposite each other and configured as parallel plate electrodes, whereby a plasma generating space is formed between the first and second electrodes, a high frequency power supply unit for forming a high frequency electric field between the first and second electrodes, a gas supply unit for supplying a processing gas for generating plasma into the plasma generating space, a plasma introducing unit for introducing the plasma generated in the plasma generating space into the processing space, and a heat transfer member made of an insulator arranged between the first and second electrodes to thermally connect them and to suppress the generation of parasitic capacitance, and fitted into recesses formed in the first and second electrodes; forming a high frequency electric field between the first electrode and the second electrode; supplying the processing gas into the plasma generation space and generating plasma by the high frequency electric field; introducing the plasma into the processing space through the plasma introduction part and performing plasma processing on the substrate; dissipating heat generated in the first electrode and the second electrode during the plasma processing by the heat transfer member; A plasma processing method comprising:

21. A plasma processing method for performing plasma processing on a substrate using a plasma processing apparatus, comprising: the plasma processing apparatus comprises a processing vessel having a processing space in which a substrate is placed, a plasma generating unit having first and second electrodes arranged opposite to each other and configured as parallel plate electrodes, whereby a plasma generating space is formed between the first and second electrodes, a high frequency power supply unit for forming a high frequency electric field between the first and second electrodes, a gas supply unit for supplying a processing gas for generating plasma into the plasma generating space, a plasma introducing unit for introducing the plasma generated in the plasma generating space into the processing space, and a heat transfer member made of an insulator arranged between the first and second electrodes so as to thermally connect them, wherein the distance between the first and second electrodes is set to be smaller than the plasma skin depth so that the high frequency power is propagated as a quasi-TEM wave; forming a high frequency electric field between the first electrode and the second electrode; supplying the processing gas into the plasma generation space and generating plasma by the high frequency electric field; introducing the plasma into the processing space through the plasma introduction part and performing plasma processing on the substrate; dissipating heat generated in the first electrode and the second electrode during the plasma processing by the heat transfer member; A plasma processing method comprising:

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