Plasma etching apparatus and shower head

Abstract

To appropriately switch gas in a plasma etching.SOLUTION: A plasma etching apparatus includes: a chamber; a gas supply part configured to supply gas to the chamber; and a plasma generation part configured to generate plasma from the gas supplied into the chamber. The gas supply part includes: a gas diffusion chamber in which the gas is diffused; a plurality of introduction channels through which the gas flows between the gas diffusion chamber and the chamber; and an exhaust part configured to exhaust the gas from the gas diffusion chamber. The gas diffusion chamber includes a first surface to which the introduction flow path is connected and a second surface opposed to the first surface, and a distance between the first surface and the second surface is larger than a diameter of the introduction flow path.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a plasma etching apparatus and a showerhead. [Background technology]

[0002] Patent Document 1 discloses a method for selectively etching a silicon oxide film on a substrate having a silicon nitride film and a silicon oxide film on the surface thereof, which method includes a step of intermittently exposing the substrate to at least one of a processing gas containing hydrogen fluoride gas and ammonia gas and a processing gas containing a compound containing nitrogen, hydrogen, and fluorine in a vacuum atmosphere multiple times. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-144249 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology according to the present disclosure appropriately switches gases during plasma etching. [Means for solving the problem]

[0005] One aspect of the present disclosure is a plasma etching apparatus comprising: a chamber; a gas supply unit that supplies a gas to the chamber; and a plasma generation unit that generates plasma from the gas supplied into the chamber, wherein the gas supply unit comprises a gas diffusion chamber in which the gas is diffused; a plurality of inlet channels that allow the gas to flow between the gas diffusion chamber and the chamber; and an exhaust unit that exhausts the gas from the gas diffusion chamber, wherein the gas diffusion chamber comprises a first surface to which the inlet channels are connected and a second surface opposite to the first surface, and a distance between the first surface and the second surface is greater than a diameter of the inlet channels. Plasma etching equipment. [Effects of the Invention]

[0006] According to the present disclosure, gas switching can be performed appropriately in plasma etching. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an explanatory diagram illustrating a configuration example of a plasma etching system according to an embodiment. [Figure 2] 1 is a cross-sectional view showing a configuration example of a plasma etching apparatus according to an embodiment. [Figure 3] FIG. 2 is a schematic diagram illustrating an example of the configuration of a gas supply unit according to an embodiment. [Figure 4] FIG. 2 is a perspective view showing an outline of a configuration example of a gas diffusion chamber according to an embodiment. [Figure 5] FIG. 2 is a cross-sectional plan view showing an outline of a configuration example of a gas diffusion chamber according to an embodiment. [Figure 6] FIG. 2 is a longitudinal cross-sectional view showing an outline of a configuration example of a gas diffusion chamber according to an embodiment. [Figure 7] FIG. 10 is a plan view showing an outline of a configuration example of a third flow channel according to the embodiment. [Figure 8] 1 is a sequence chart showing an outline of a configuration example of a gas supply method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] 2. Description of the Related Art In a semiconductor device manufacturing process, a plasma etching process is performed in which a desired process gas is supplied to a process module containing a semiconductor wafer (hereinafter referred to as a "substrate"), and the substrate is etched with plasma from the process gas.

[0009] Substrates to be processed by plasma etching include those having multiple layers stacked on the surface with different etching selectivities. When processing such substrates, process gases with high selectivities for each layer may be sequentially supplied, and one process gas may be supplied to etch one layer, and then another process gas may be supplied to etch another layer.

[0010] Patent Document 1 discloses a method for selectively etching a silicon oxide film on a substrate having a silicon nitride film and a silicon oxide film on the surface thereof, which comprises a step of intermittently exposing the substrate to at least one of a processing gas containing hydrogen fluoride gas and ammonia gas and a processing gas containing a compound containing nitrogen, hydrogen, and fluorine in a vacuum atmosphere multiple times.

[0011] On the other hand, when one process gas is exhausted and then another process gas is supplied, the gas diffusion chamber may be exhausted through a shower head by an exhaust system connected to the chamber. In such cases, the flow rate of the process gas at the gas inlet of the shower head may become a rate limiting factor, preventing rapid exhaust of the gas diffusion chamber.

[0012] The inventors of the present invention have conducted extensive research into the evacuation of such gas diffusion chambers and have come up with the idea of ​​providing an exhaust section that can evacuate the gas diffusion chamber at a sufficient speed. They have also found that by optimizing the configuration of the gas diffusion chamber equipped with such an exhaust section, the gas diffusion chamber can be evacuated more quickly. Furthermore, they have found that, depending on the configuration of the gas diffusion chamber, the pressure inside the gas diffusion chamber may become too high when gas is supplied, which could result in abnormal discharges and other problems.

[0013] Therefore, the technology disclosed herein enables rapid exhaust of the gas diffusion chamber while preventing the pressure in the gas diffusion chamber from becoming too high when gas is supplied, by providing an appropriate configuration for the gas diffusion chamber provided with an exhaust section.

[0014] Hereinafter, the configuration of the substrate processing apparatus according to this embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0015] <Plasma etching system> FIG. 1 is a diagram illustrating an example of the configuration of a plasma etching system. In one embodiment, the plasma etching system includes a plasma etching apparatus 1 and a control unit 2. The plasma etching system is an example of a substrate processing system, and the plasma etching apparatus 1 is an example of a substrate processing apparatus. The plasma etching apparatus 1 includes a plasma etching chamber 10 (hereinafter referred to as "chamber 10"), a substrate support 11, and a plasma generation unit 12. The chamber 10 has a plasma processing space. The chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas box 21 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0016] The plasma generation unit 12 is configured to generate a plasma PL from at least one processing gas supplied into the plasma processing space. The plasma PL formed in the plasma processing space may be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron-cyclotron-resonance plasma (ECR plasma), a helicon wave plasma (HWP), or a surface wave plasma (SWP). Various types of plasma generation units may be used, including an alternating current (AC) plasma generation unit and a direct current (DC) plasma generation unit. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0017] The controller 2 processes computer-executable instructions that cause the plasma etching apparatus 1 to perform the various steps described in this disclosure. The controller 2 may be configured to control each element of the plasma etching apparatus 1 to perform the various steps described herein. In one embodiment, part or all of the controller 2 may be included in the plasma etching apparatus 1. The controller 2 may include a processor 2a1, a memory 2a2, and a communication interface 2a3. The controller 2 may be implemented, for example, by a computer 2a. The processor 2a1 may be configured to read a program from the memory 2a2 and execute the read program to perform various control operations. The program may be stored in the memory 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the memory 2a2 and read from the memory 2a2 by the processor 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processor 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma etching apparatus 1 via a communication line such as a local area network (LAN).

[0018] <Plasma etching equipment> An example of the configuration of a capacitively coupled plasma etching apparatus 1 as an example of a substrate processing apparatus will be described below. Figure 2 is a diagram for explaining an example of the configuration of the capacitively coupled plasma etching apparatus 1.

[0019] The plasma etching apparatus 1 includes a chamber 10, a substrate support 11, a gas supply 20, a power supply 30, and an exhaust system 40.

[0020] The substrate support 11 is disposed within the chamber 10. The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0021] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Alternatively, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0022] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0023] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0024] The gas supply unit 20, which will be described in detail later, is configured to introduce gases supplied from a gas box 21 provided outside the gas supply unit 20 into the chamber 10. The gas supply unit includes a supply passage 22, a gas inlet, and an exhaust section 24. The gas box 21 is configured to supply multiple gases supplied from gas sources while controlling the flow rates. Note that the gas box 21 may be included in the gas supply unit 20. The supply passage 22 is configured to supply the gas supplied from the gas box 21 to the gas inlet. The gas inlet is configured to introduce two or more process gases into the chamber 10. The exhaust section 24 is configured to exhaust the gases introduced into the gas inlet. The gas inlet includes a showerhead 25. The showerhead 25 is disposed above the substrate support 11. In one embodiment, the showerhead 25 forms at least a part of the ceiling of the chamber 10. The chamber 10 has a plasma processing space 10s defined by the showerhead 25, a sidewall 10a of the chamber 10, and the substrate support 11. The chamber 10 is grounded. The showerhead 25 and the substrate support 11 are electrically insulated from the housing of the chamber 10.

[0025] The showerhead 25 is configured to introduce the processing gas from the gas box 21 into the plasma processing space 10s. The showerhead 25 has at least one gas supply port 25a, at least one gas diffusion chamber 25b, and multiple introduction channels 25c. The processing gas supplied to the gas supply port 25a passes through the gas diffusion chamber 25b and is introduced into the plasma processing space 10s from the multiple introduction channels 25c. The showerhead 25 also includes at least one upper electrode. In addition to the showerhead 25, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0026] The gas box 21 may include at least one gas source 26 and at least one flow controller 27. In one embodiment, the gas box 21 is configured to supply two or more process gases from respective gas sources 26 through respective flow controllers 27 to the showerhead 25. Each flow controller 27 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas box 21 may include at least one flow modulation device that modulates or pulses the flow rate of at least one process gas.

[0027] The power supply 30 includes an RF power supply 31 coupled to the chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This generates a plasma PL from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0028] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0029] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0030] The power supply 30 may also include a DC power supply 32 coupled to the chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0031] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0032] The exhaust system 40 may be connected to a gas exhaust port 10e provided at the bottom of the chamber 10, for example. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0033] <Gas supply section> The gas supply unit 20 according to this embodiment will be described below with reference to Figures 3 to 7. Figure 3 is a schematic diagram showing an outline of the configuration of the gas supply unit 20. For ease of explanation, Figure 3 omits illustration of the chamber 10, part of the substrate support unit 11, the plasma generation unit 12, and the like in the plasma etching apparatus 1.

[0034] The gas box 21 includes a first gas source 201 that supplies a first gas and a second gas source 202 that supplies a second gas. Each of the first gas source 201 and the second gas source 202 may include a plurality of gas sources. Alternatively, some of the gas sources may be shared by the first gas source 201 and the second gas source 202. The gas box 21 according to this embodiment is provided outside the gas supply unit 20, and supplies gas to the supply flow path 22 of the gas supply unit 20 via a desired flow path.

[0035] The supply flow path 22 includes a first flow path 211 downstream of the first gas source 201 through which a first gas flows. It also includes a second flow path 212 downstream of the second gas source 202 through which a second gas flows. The first flow path 211 and the second flow path 212 merge downstream of these flow paths to form a third flow path 213 through which one of the gases flows. The third flow path 213 according to this embodiment includes a branch flow path 214 that distributes the gas so that the pressure in the surface direction is uniform. The third flow path 213 is connected to a plurality of gas supply ports 25a in the shower head 25 at the downstream end of the branch flow path 214. The third flow path 213 also includes a collecting flow path 215 that distributes the gas between the first flow path 211 or the second flow path 212 and the branch flow path 214.

[0036] The first flow path 211 includes a first valve 216 at the end connected to the third flow path 213. The second flow path 212 includes a second valve 217 at the end connected to the third flow path 213.

[0037] According to the supply flow path 22 having such a configuration, for example, with the first valve 216 open and the second valve 217 closed, a first gas supplied from the first gas source 201 flows through the first flow path 211 and into the collecting flow path 215 of the third flow path 213. The first gas flows from the collecting flow path 215 into the branch flow path 214. The first gas is dispersed in the branch flow path 214 and flows from the downstream end of the branch flow path 214 into the gas diffusion chamber 25b via the multiple gas supply ports 25a in the shower head 25. The first gas is diffused in the gas diffusion chamber 25b so that the pressure distribution in the surface direction becomes approximately uniform, and then is introduced into the chamber 10 via the introduction flow path 25c.

[0038] The gas diffusion chamber 25b according to this embodiment includes a first surface 221 to which multiple introduction channels 25c are connected and a second surface 222 opposite the first surface 221, and defines a flat, substantially cylindrical internal space with these surfaces as the bottom. The gas diffusion chamber 25b also includes multiple pillars 223. The pillars 223 are disposed such that their lower surfaces contact the first surface 221 and their upper surfaces contact the second surface 222.

[0039] 4 is a perspective view seen from the second surface 222 side, showing an outline of the configuration of the showerhead 25. For convenience, FIG. 4 shows the components of the showerhead 25 above the second surface 222 in a see-through manner. The pillars 223 are members that occupy a portion of the gas diffusion chamber 25b to prevent the flow of the processing gas. The introduction flow path 25c is connected to a portion of the first surface 221 where the pillars 223 are not provided.

[0040] The pillar portions 223 reduce the volume of the internal space of the gas diffusion chamber 25b through which gas can flow by the volume of the pillar portions 223. This allows the gas diffusion chamber 25b to be quickly evacuated.

[0041] Fig. 5 is a cross-sectional view schematically illustrating the configuration of shower head 25 including gas diffusion chamber 25b when viewed in the direction AA in Fig. 3. Pillar portions 223 are arranged to have rotational symmetry in a plan view (horizontal cross-sectional view), and in the example of Fig. 5, have 90-degree rotational symmetry.

[0042] The shape of one pillar portion 223 according to this embodiment is a shape that includes a trajectory that is formed when a cylinder indicated by a dashed line in the plan view of Fig. 5 is rotated in the direction of the arrow around the center C of the gas diffusion chamber 25b as an axis. With pillar portion 223 having such a shape, the gas diffused in the gas diffusion chamber 25b is smoothly diverted when it collides with pillar portion 223, and the gas can be smoothly diffused inside the gas diffusion chamber 25b.

[0043] 6 is a cross-sectional view schematically illustrating the configuration of the showerhead 25 including the gas diffusion chamber 25b as viewed in the direction BB in FIG. 5. The introduction channel 25c includes a first portion 231 connected to the first surface 221 and a second portion 232 connected to the chamber 10. The first portion 231 and the second portion 232 are both hollow holes having substantially cylindrical sidewalls, and the first portion 231 and the second portion 232 are connected to each other so that gas can flow therebetween. In addition, a funnel-shaped portion 233 having a funnel-shaped opening is provided at the end of the second portion 232 connected to the chamber 10.

[0044] The distance d between the first surface 221 and the second surface 222 is greater than the diameter of the introduction flow path 25c. With the gas diffusion chamber 25b having such a distance d, the gas supplied to the gas diffusion chamber 25b can be smoothly diffused in the internal space, and excessive pressure in the gas diffusion chamber can be prevented. On the other hand, by making the distance d smaller than the desired upper limit, the volume of the gas diffusion chamber 25b can be sufficiently reduced, enabling rapid exhaust of the gas from the gas diffusion chamber 25b. The diameter of the introduction flow path 25c refers to the shortest diameter of the introduction flow path 25c. In this embodiment, the shortest diameter of the introduction flow path 25c is the second diameter φ2 of the second portion 232.

[0045] In one embodiment, in order to prevent the pressure in the gas diffusion chamber from becoming too high, when the second diameter φ2 of the second portion 232 is 0.8 mm, the distance d is 1.0 mm or more. On the other hand, in order to enable rapid gas exhaust, the distance d is 3.0 mm or less, more preferably 1.5 mm or less.

[0046] In one embodiment, the interval p between one pillar portion 223 and another pillar portion 223 is larger than the diameter of the introduction flow path 25c. According to the gas diffusion chamber 25b including the plurality of pillar portions 223 with such an interval p, the gas supplied to the gas diffusion chamber 25b can be smoothly diffused in the internal space, and the pressure inside the gas diffusion chamber can be prevented from becoming too high.

[0047] In one embodiment, when the second diameter φ2 of the second portion 232 is 0.8 mm, the interval p is 1.0 mm or more. Note that the interval p refers to the distance between the points where one pillar portion 223 and another pillar portion 223 are closest to each other.

[0048] The first portion 231 of the introduction flow path 25c has a first diameter φ1 and a first axial length h1. The second portion 232 has a second diameter φ2 and a second axial length h2. In one embodiment, the first diameter φ1 is greater than the second diameter φ2. The first length h1 is greater than the second length h2. The introduction flow path 25c having such diameters and lengths allows the gas in the gas diffusion chamber 25b to be smoothly introduced into the chamber 10, even when the distance d between the first surface 221 and the second surface 222 of the gas diffusion chamber 25b is reduced, thereby preventing the pressure in the gas diffusion chamber from becoming too high. As shown in FIG. 6 , the second portion 232 may have a funnel-shaped portion 233 at the end connected to the chamber 10. In this case, the second diameter φ2 refers to the shortest diameter of the second portion 232 excluding the funnel-shaped portion 233.

[0049] Returning to FIG. 3 , the exhaust unit 24 is connected to the collecting passage 215. The exhaust unit 24 includes an exhaust passage 241 and a vacuum pump 242. The exhaust passage 241 has an end connected to the collecting passage 215 and an end connected to the vacuum pump 242, and is configured to allow gas to flow therethrough. The vacuum pump 242 may include a turbomolecular pump, a dry pump, or a combination thereof. The vacuum pump 242 may also be included in the exhaust system 40. The exhaust unit 24 also includes an exhaust valve 243 at the end of the exhaust passage 241 that is connected to the collecting passage 215.

[0050] FIG. 7 is a plan view schematically illustrating a portion of the third flow path 213 according to this embodiment. In FIG. 7, the gas diffusion chamber 25b is indicated by a dotted line to indicate the positional relationship between the third flow path 213 and the gas diffusion chamber 25b. The branch flow path 214 ultimately branches into eight flow paths at the end on the gas diffusion chamber 25b side, and each end is connected to a gas supply port 25a. The gas supply ports 25a are provided in a portion of the second surface 222 where no column portion 223 is provided. The gas supply ports 25a are arranged rotationally symmetrically in a plan view, i.e., 90° rotationally symmetrically in the example of FIG. 7. While the number of gas supply ports 25a is eight in the example of FIG. 7, this number is not limited to eight, and any desired number can be used as long as the gas supply ports 25a are arranged rotationally symmetrically. The branch flow path 214 can be configured to have any desired number of branches depending on the number of gas supply ports 25a. In the branch flow paths 214, the distances from any position in the collecting flow path 215 to the respective gas supply ports 25a are all approximately equal. The branch flow paths 214 allow the gas supplied from the gas box 21 to the third flow path 213 to flow through the gas diffusion chamber 25b while being uniformly dispersed.

[0051] The exhaust flow path 241 of the exhaust unit 24 is connected to the collecting flow path 215 of the third flow path 213. The exhaust unit 24 allows the gas diffusion space 25b to be evacuated without passing through the introduction flow path 25c, unlike when the gas diffusion space 25b is evacuated by the exhaust system 40 connected to the chamber 10. This allows the gas diffusion space 25b to be evacuated quickly without the flow rate of the gas in the introduction flow path 25c becoming a rate limiting factor.

[0052] Furthermore, since the distances from any position on the collecting flow path 215 to each gas supply port 25a are approximately equal, the positions to which the exhaust flow paths 241 are connected are also approximately equal distances from each gas supply port 25a. By exhausting the gas diffusion chamber 25b from each gas supply port 25a via the branch flow paths 214, exhaust can be performed from positions equally spaced apart in the surface direction of the gas diffusion chamber 25b. This allows the gas in the gas diffusion chamber 25b to be evenly exhausted while maintaining uniformity in the surface direction of the gas pressure inside the gas diffusion chamber 25b.

[0053] Although only one gas diffusion chamber 25b is provided in the above embodiment, the present invention is not limited to this. The shower head 25 may be provided with a plurality of gas diffusion chambers 25b divided concentrically from the center of the shower head 25 outward. In this case, a gas box 21 and a supply flow path 22 or an exhaust unit 24 may be provided to supply or exhaust gas to or from each gas diffusion chamber 25b.

[0054] <Gas supply method> Next, a gas supply method for supplying gas to the chamber 10 using the gas supply unit 20 according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a sequence chart for controlling the on / off of the first gas supplied from the first gas source 201 or the second gas supplied from the second gas source 202, and the on / off of exhaust from the gas diffusion chamber 25b in the gas supply method.

[0055] The gas supply method is a method that includes switching the gas supplied to chamber 10 from a first gas to a second gas, or from the second gas to the first gas, and includes the following steps ST11 to ST13. In FIG. 8, for the first gas or the second gas, a state in which the gas is being supplied is referred to as an "on" state, and a state in which the gas is not being supplied is referred to as an "off" state. Regarding exhaust, a state in which exhaust from exhaust unit 24 to gas diffusion chamber 25b is being performed is referred to as an "on" state, and a state in which exhaust is not being performed is referred to as an "off" state.

[0056] In step ST11, the supply of the first gas from the first gas source 201 is started, and after a desired period of time, the supply of the first gas is stopped.

[0057] In step ST12, the gas diffusion space 25b is evacuated by the exhaust unit 24. After the evacuation of the gas diffusion space 25b is completed, the evacuation of the gas diffusion space 25b is stopped.

[0058] In step ST13, the supply of the second gas from the second gas source 202 is started, and after a desired period of time, the supply of the second gas is stopped.

[0059] By performing the above steps ST11 to ST13, the gas supplied to the chamber 10 can be switched from the first gas to the second gas. After switching to the second gas, step ST12 is performed to evacuate the gas diffusion chamber 25b, and then step ST11 is performed again to switch from the second gas to the first gas. Thereafter, by repeating the above steps ST11 to ST13, gases can be supplied to the chamber 10 while switching between the first gas and the second gas, and the desired processing can be performed.

[0060] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0061] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that would be apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0062] Note that the following configuration examples also fall within the technical scope of the present disclosure. (1) A plasma etching apparatus, a chamber; a gas supply unit that supplies a gas to the chamber; a plasma generating unit that generates plasma from a gas supplied into the chamber; Equipped with The gas supply unit a gas diffusion chamber in which the gas is diffused; a plurality of inlet channels through which the gas flows between the gas diffusion chamber and the chamber; an exhaust unit that exhausts the gas from the gas diffusion chamber, The gas diffusion chamber is a first surface to which the introduction channel is connected; a second surface opposite to the first surface, The distance between the first surface and the second surface is greater than the diameter of the introduction channel. Plasma etching equipment. (2) A plasma etching apparatus as described in (1) above, wherein the second surface is provided with a plurality of gas supply ports, the gas is supplied to the gas diffusion chamber via the plurality of gas supply ports, and the plurality of gas supply ports are arranged rotationally symmetrically in a planar view. (3) The gas supply unit includes a supply flow path through which the gas supplied to the gas diffusion chamber flows, the supply flow path includes a plurality of branch flow paths through which the gas flows in a dispersed manner and which are connected to the plurality of gas supply ports, respectively, and a collecting flow path through which the gas supplied to the plurality of branch flow paths flows; The plasma etching apparatus according to (2) above, wherein the exhaust section includes an exhaust flow path connected to the collecting flow path. (4) The plasma etching apparatus according to any one of (1) to (3) above, wherein the distance between the first surface and the second surface is 1.0 mm or more and 3.0 mm or less. (5) A plasma etching apparatus according to any one of (1) to (4) above, wherein the gas diffusion chamber comprises a plurality of pillars, the pillars being arranged rotationally symmetrically in a plan view, and the spacing between the pillars being greater than the diameter of the inlet flow path. (6) A plasma etching apparatus according to any one of (1) to (5) above, wherein the inlet flow path comprises a first portion connected to the first surface and a second portion connected to the chamber, the first portion having a first diameter and a first axial length, the second portion having a second diameter and a second axial length, the first diameter being larger than the second diameter, and the first length being larger than the second length. (7) A plasma etching apparatus, a chamber; a gas supply unit that supplies a gas to the chamber; The gas supply unit a gas diffusion chamber in which the gas is diffused; a supply flow path through which the gas supplied to the gas diffusion chamber flows; an exhaust unit that exhausts the gas from the gas diffusion chamber, the supply flow path includes a plurality of branch flow paths through which the gas flows in a dispersed manner, and a collecting flow path through which the gas flows between the plurality of branch flow paths, The exhaust unit includes an exhaust flow path connected to the collecting flow path. Plasma etching equipment. (8) A showerhead for introducing gas into a chamber in a plasma etching apparatus, a gas diffusion chamber in which the gas is diffused; a plurality of introduction channels through which the gas flows between the gas diffusion chamber and the chamber; The gas diffusion chamber is a first surface to which the introduction channel is connected; a second surface opposite to the first surface, The distance between the first surface and the second surface is greater than the diameter of the introduction channel. Shower head. [Explanation of symbols]

[0063] 1. Plasma etching equipment 10 Chambers 20 Gas supply unit 24 Exhaust section 25b Gas diffusion chamber 25c Inlet channel 221 First Side 222 Second Side

Claims

1. A plasma etching apparatus, a chamber; a gas supply unit that supplies a gas to the chamber; a plasma generating unit that generates plasma from a gas supplied into the chamber; Equipped with The gas supply unit a gas diffusion chamber in which the gas is diffused; a plurality of inlet channels through which the gas flows between the gas diffusion chamber and the chamber; an exhaust unit that exhausts the gas from the gas diffusion chamber, The gas diffusion chamber is a first surface to which the introduction channel is connected; a second surface opposite the first surface, a distance between the first surface and the second surface is greater than a diameter of the introduction channel; Plasma etching equipment.

2. 2. The plasma etching apparatus according to claim 1, wherein the second surface is provided with a plurality of gas supply ports, the gas is supplied to the gas diffusion chamber via the plurality of gas supply ports, and the plurality of gas supply ports are arranged rotationally symmetrically in a plan view.

3. the gas supply unit includes a supply flow path through which the gas to be supplied to the gas diffusion chamber flows; the supply flow path includes a plurality of branch flow paths through which the gas flows in a dispersed manner and which are connected to the plurality of gas supply ports, respectively, and a collecting flow path through which the gas supplied to the plurality of branch flow paths flows; The plasma etching apparatus according to claim 2 , wherein the exhaust section includes an exhaust passage connected to the collecting passage.

4. 4. The plasma etching apparatus according to claim 1, wherein the distance between the first surface and the second surface is 1.0 mm or more and 3.0 mm or less.

5. 4. The plasma etching apparatus according to claim 1, wherein the gas diffusion chamber comprises a plurality of pillars, the pillars being arranged rotationally symmetrically in a plan view, and the spacing between the pillars being greater than a diameter of the inlet flow path.

6. 4. The plasma etching apparatus of claim 1, wherein the introduction flow path comprises a first portion connected to the first surface and a second portion connected to the chamber, the first portion having a first diameter and a first axial length, the second portion having a second diameter and a second axial length, the first diameter being larger than the second diameter, and the first length being larger than the second length.

7. A plasma etching apparatus, a chamber; a gas supply unit that supplies a gas to the chamber; The gas supply unit a gas diffusion chamber in which the gas is diffused; a supply flow path through which the gas supplied to the gas diffusion chamber flows; an exhaust unit that exhausts the gas from the gas diffusion chamber, the supply flow path includes a plurality of branch flow paths through which the gas flows in a dispersed manner, and a collecting flow path through which the gas flows between the plurality of branch flow paths, The exhaust unit includes an exhaust flow path connected to the collecting flow path. Plasma etching equipment.

8. 1. A showerhead for introducing gas into a chamber in a plasma etching apparatus, comprising: a gas diffusion chamber in which the gas is diffused; a plurality of introduction channels through which the gas flows between the gas diffusion chamber and the chamber; The gas diffusion chamber is a first surface to which the introduction channel is connected; a second surface opposite the first surface, a distance between the first surface and the second surface is greater than a diameter of the introduction channel; Shower head.

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