Shower head and plasma processing apparatus

Abstract

To provide a technique of preventing an abnormal discharge generated in an inner part of a shower head.SOLUTION: A shower head for supplying a processing gas to an inner part of a processing chamber, comprises: a cooling plate that has a gas diffusion chamber and a plurality of first penetration holes that is penetrated from the gas diffusion chamber to a first surface on the processing chamber side, and in which the processing gas flows; an upper electrode that includes a second surface that is contacted to the first surface of the cooling plate, and a third surface that forms an inner surface of the processing chamber, and includes a plurality of second penetration holes that is penetrated from the second surface to the third surface; and a plurality of concave parts that is formed on the first or second surface, and is provided so as to be separated each other. Any one of the plurality of first penetration holes is connected via at least two second penetration holes of the plurality of second penetration holes and any one of the plurality of concave parts.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In a plasma processing apparatus, a shower head is used to supply a processing gas into a processing chamber (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2010-514160 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for preventing abnormal discharge occurring inside a showerhead. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a showerhead for supplying a process gas into a process chamber, the showerhead comprising: a cooling plate having a gas diffusion chamber and a plurality of first through holes penetrating from the gas diffusion chamber to a first surface facing the process chamber and through which the process gas flows; a second surface in contact with the first surface of the cooling plate and a third surface forming an inner surface of the process chamber, the upper electrode having a plurality of second through holes penetrating from the second surface to the third surface; and a plurality of recesses formed in the first surface or the second surface and spaced apart from each other, wherein any of the plurality of first through holes is connected to at least two of the plurality of second through holes via any one of the plurality of recesses. Effect of the Invention

[0006] The present disclosure provides a technique for preventing abnormal discharge occurring inside a showerhead. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system according to this embodiment. [Diagram 2] FIG. 2 is a plan view of an example of an upper electrode of a shower head of the plasma processing apparatus according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of an example of a shower head of the plasma processing apparatus according to the first embodiment. [Figure 4] FIG. 4 is a plan view of an example of an upper electrode of a shower head of the plasma processing apparatus according to the second embodiment. [Diagram 5] FIG. 5 is a plan view of an example of an upper electrode of a shower head of a plasma processing apparatus according to the third embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of the temperature distribution in the shower head of the plasma processing apparatus according to this embodiment. [Figure 7] FIG. 7 is a diagram showing an operation result of an example of the plasma processing apparatus according to this embodiment. [Figure 8] FIG. 8 is a diagram showing an operation result of an example of the plasma processing apparatus according to this embodiment. [Figure 9] FIG. 9 is a diagram showing an operation result of an example of the plasma processing apparatus according to this embodiment. [Figure 10] FIG. 10 is a diagram showing the operation result of the plasma processing apparatus of the reference example. [Figure 11] FIG. 11 is a diagram showing the operation result of the plasma processing apparatus of the reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In this specification and the drawings, substantially the same configurations are denoted by the same reference numerals to avoid redundant description. In order to facilitate understanding, the scale of each part in the drawings may differ from the actual scale.

[0009] In the directions of parallel, right angle, orthogonal, horizontal, vertical, up / down, left / right, etc., deviations are permitted to the extent that they do not impair the effects of the embodiment. The shape of the corners is not limited to right angles and may be rounded in an arch shape. Parallel, right angle, orthogonal, horizontal, and vertical may include approximately parallel, approximately right angle, approximately orthogonal, approximately horizontal, and approximately vertical.

[0010] An example of the configuration of a plasma processing system will be described below with reference to FIG.

[0011] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed in the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 has at least one gas inlet for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space. The side wall 10a is grounded. The shower head 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10. As will be described later, the shower head 13 includes a cooling plate and an upper electrode.

[0012] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W, and an annular region (ring support surface) 111b for supporting the ring assembly 112. 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. In one embodiment, the main body 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has a substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not shown, the substrate support 11 may include a temperature adjustment module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0013] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The shower head 13 also includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. In addition to the shower head 13, the gas introduction unit may include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0014] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include one or more flow modulation devices to modulate or pulse a flow rate of the at least one process gas.

[0015] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to a conductive member of the substrate support 11 and / or a conductive member of the showerhead 13. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of a plasma generating unit configured to generate a plasma from one or more processing gases in the plasma processing chamber 10. In addition, by supplying a bias RF signal to the conductive member of the substrate support 11, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0016] 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 the conductive member of the substrate support 11 and / or the conductive member of the shower head 13 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 13 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support 11 and / or the conductive member of the shower head 13. The second RF generating unit 31b is coupled to the conductive member of the substrate support 11 via at least one impedance matching circuit, and is configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated bias RF signal or signals are provided to the conductive members of the substrate support 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0017] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing 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 a conductive member of the substrate support 11 and configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the first DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the second DC generator 32b is connected to a conductive member of the showerhead 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the showerhead 13. In various embodiments, at least one of the first and second DC signals may be pulsed. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0018] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. 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.

[0019] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various steps described herein. In one embodiment, a part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on a program stored in the storage unit 2a2. 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 processing apparatus 1 via a communication line such as a local area network (LAN).

[0020] First Embodiment [Shower Head 13] Fig. 2 is a plan view of the upper electrode 13B of the shower head 13 according to the first embodiment. Fig. 3 is a cross-sectional view of the shower head 13 according to the first embodiment. Fig. 3 is specifically a cross-sectional view taken along line II in Fig. 2.

[0021] The shower head 13 has a plurality of recesses 13Bg on each of the plurality of concentric circles. The shower head 13 has a plurality of through holes 13Ah, 13Bh1, and 13Bh2 corresponding to the recesses 13Bg. In Fig. 2, the recesses 13Bg are provided on one concentric circle as an example of the plurality of recesses 13Bg provided on the concentric circles. The same applies to Figs. 4 and 5.

[0022] The showerhead 13 supplies a processing gas to the inside of the plasma processing chamber 10. The showerhead 13 includes a cooling plate 13A and an upper electrode 13B.

[0023] The cooling plate 13A cools the entire shower head 13. The cooling plate 13A is made of, for example, aluminum. The cooling plate 13A has a flow path through which, for example, water, antifreeze liquid, etc., flows. The cooling plate 13A has a gas diffusion chamber 13b. The lower surface 1 of the cooling plate 13A on the plasma processing space 10s side is 3 The AS, that is, the surface on the processing chamber side, is in contact with the upper electrode 13B.

[0024] The cooling plate 13A is provided with a gas diffusion chamber 13b and a lower surface 1 3 The gas diffusion chamber 13b has a through hole 13Ah penetrating to the AS. The process gas introduced into the gas diffusion chamber 13b passes through the through hole 13Ah and is discharged to the upper electrode 13B side. That is, the process gas flows through the through hole 13Ah.

[0025] The upper electrode 13B is an electrode that supplies high frequency power to the plasma processing space 10s. The upper electrode 13B is made of, for example, silicon. An upper surface 13BS1 of the upper electrode 13B contacts the cooling plate 13A. A lower surface 13BS2 of the upper electrode 13B contacts the plasma processing space 10s. That is, the lower surface 13BS2 of the upper electrode 13B forms the inner surface of the plasma processing space 10s.

[0026] The upper electrode 13B has a plurality of recesses 13Bg on the upper surface 13BS1. Each of the recesses 13Bg is formed in an arc shape in the circumferential direction with respect to the center CT. The recesses 13Bg are spaced apart from one another. Each of the recesses 13Bg is connected to one of the through holes 13Ah of the cooling plate 13A. The through hole 13Ah is connected to the center of the recess 13Bg.

[0027] The upper electrode 13B has a through hole 13Bh1 and a through hole 13Bh2 that penetrate from the bottom of each of the recesses 13Bg to the lower surface 13BS2 in each of the recesses 13Bg. The through hole 13Bh1 has a narrowed portion 13Bj1 at a connection portion with the recess 13Bg. The through hole 13Bh2 has a narrowed portion 13Bj2 at a connection portion with the recess 13Bg.

[0028] The through holes 13Bh1 and 13Bh2 are provided at the ends of the recess 13Bg.

[0029] The plasma processing gas supplied to the gas diffusion chamber 13b is introduced into the recess 13Bg through the through-hole 13Ah. The plasma processing gas introduced into the recess 13Bg is branched into the through-hole 13Bh1 and the through-hole 13Bh2 at the recess 13Bg, and is introduced into the plasma processing space 10s. That is, the processing gas flows through the through-hole 13Bh1 and the through-hole 13Bh2 via the recess 13Bg.

[0030] The shower head 13 can reduce the pressure of the plasma processing gas at the boundary between the cooling plate 13A and the upper electrode 13B by branching the plasma processing gas supplied to the gas diffusion chamber 13b from the through-holes 13Ah to the recesses 13Bg. Reducing the pressure of the plasma processing gas can prevent abnormal discharge from occurring at the boundary between the cooling plate 13A and the upper electrode 13B.

[0031] The recess 13Bg is not limited to being arc-shaped, but may be linear. Also, the recess 13Bg is formed in the circumferential direction, but may be formed in the radial direction.

[0032] <Second embodiment> [Shower Head 113] 4 is a plan view of an upper electrode 113B of the shower head according to the second embodiment. The shower head according to the second embodiment includes an upper electrode 113B instead of the upper electrode 13B of the shower head 13 according to the first embodiment.

[0033] The upper electrode 113B has a recess 113Bg instead of the recess 13Bg of the upper electrode 13B. The upper electrode 113B has a plurality of recesses 113Bg on the upper surface 113BS1. Each of the plurality of recesses 113Bg is formed in a cross shape. That is, a circular arc groove formed in the circumferential direction and a linear groove formed in the radial direction are combined with each other with respect to the center CT. Each of the plurality of recesses 113Bg is connected to one of the plurality of through holes 13Ah of the cooling plate 13A. The through hole 13Ah is connected to the center of the recess 113Bg.

[0034] The upper electrode 113B has through holes 113Bh1, 113Bh2, 113Bh3, and 113Bh4 that penetrate from the bottom of each of the recesses 113Bg to the lower surface in contact with the plasma processing space 10s. Each of the through holes 113Bh1, 113Bh2, 113Bh3, and 113Bh4 has a narrowed portion at a connection portion with the recess 113Bg.

[0035] The through holes 113Bh1, 113Bh2, 113Bh3 and 113Bh4 are provided at the ends of the recess 113Bg.

[0036] The plasma processing gas supplied to the gas diffusion chamber 13b is introduced into the recess 113Bg through the through-hole 13Ah. The plasma processing gas introduced into the recess 113Bg is branched into the through-hole 113Bh1, the through-hole 113Bh2, the through-hole 113Bh3, and the through-hole 113Bh4 in the recess 113Bg, and is introduced into the plasma processing space 10s.

[0037] In the showerhead according to the second embodiment, the plasma processing gas supplied to the gas diffusion chamber 13b is branched from the through-holes 13Ah to the recesses 113Bg, thereby making it possible to reduce the pressure of the plasma processing gas at the boundary between the cooling plate 13A and the upper electrode 113B. By reducing the pressure of the plasma processing gas, it is possible to prevent abnormal discharge from occurring at the boundary between the cooling plate 13A and the upper electrode 113B.

[0038] <Third embodiment> [Shower Head 213] 5 is a plan view of an upper electrode 213B of the shower head according to the third embodiment. The cooling plate of the shower head according to the third embodiment includes an upper electrode 213B instead of the upper electrode 13B of the shower head 13 according to the first embodiment.

[0039] The upper electrode 213B has a recess 213Bg instead of the recess 13Bg of the upper electrode 13B. The upper electrode 213B has a plurality of recesses 213Bg on the upper surface 213BS1 on the circumference of the center CT. Each of the plurality of recesses 213Bg is formed in a cylindrical shape. Each of the plurality of recesses 213Bg is connected to one of the plurality of through holes 13Ah of the cooling plate 13A. The through hole 13Ah is connected to the center of the recess 213Bg.

[0040] The upper electrode 213B has through holes 213Bh1, 213Bh2, and 213Bh3 that penetrate from the bottom of each of the recesses 213Bg to the lower surface in contact with the plasma processing space 10s. Each of the through holes 213Bh1, 213Bh2, and 213Bh3 has a narrowed portion at a connection portion with the recess 213Bg.

[0041] The through holes 213Bh1, 213Bh2, and 213Bh3 are provided at an equal distance from the through hole 13Ah.

[0042] The plasma processing gas supplied to the gas diffusion chamber 13b is introduced into the recess 213Bg through the through-hole 13Ah. The plasma processing gas introduced into the recess 213Bg is branched into the through-hole 213Bh1, the through-hole 213Bh2, and the through-hole 213Bh3 in the recess 213Bg, and is introduced into the plasma processing space 10s.

[0043] In the showerhead according to the third embodiment, the plasma processing gas supplied to the gas diffusion chamber 13b is branched from the through-holes 13Ah to the recesses 213Bg, thereby making it possible to reduce the pressure of the plasma processing gas at the boundary between the cooling plate 13A and the upper electrode 213B. By reducing the pressure of the plasma processing gas, it is possible to prevent abnormal discharge from occurring at the boundary between the cooling plate 13A and the upper electrode 213B.

[0044] <Temperature effect due to concave portion of upper electrode> When plasma is generated in the plasma processing space 10s, heat from the plasma is input to the upper electrode. When heat from the plasma is input to the upper electrode, the temperature of the upper electrode rises. When the temperature of the upper electrode rises, deterioration of the upper electrode progresses, and the replacement cycle becomes shorter. Therefore, in order to suppress the temperature rise of the upper electrode, the upper electrode is cooled by a cooling plate.

[0045] If the upper electrode has a recess on its upper surface, the thermal resistance between the upper electrode and the cooling plate increases, and therefore the performance of the cooling plate in cooling the upper electrode decreases.

[0046] Figure 6 shows the results of a simulation of the effect that the recess in the upper electrode has on the cooling of the upper electrode.

[0047] The simulation was performed for a disk-shaped upper electrode with a radius of 380 mm. The simulation was performed for three models of the upper electrode: a reference model, an embodiment model, and a comparison model. In the simulation, the upper surface of the upper electrode was cooled with a cooling plate, and the temperature distribution of the upper electrode was obtained when heat was input from the plasma processing space side, i.e., from the lower surface of the upper electrode. In the simulation, the material of the upper electrode was silicon.

[0048] The reference model is a model of an upper electrode that has no recess on its upper surface.

[0049] The example model is a model of an upper electrode in which a recess corresponding to the recess 13Bg of the shower head 13 of the first embodiment is formed on the upper surface of the upper electrode. In the example model, a plurality of recesses are provided at intervals on 16 concentric circles. The 16 concentric circles are provided at equal intervals within a radius of 300 mm.

[0050] The comparison model is an upper electrode model in which 16 recesses are formed in a concentric pattern on the upper surface of the upper electrode. In the comparison model, the recesses are provided around the entire circumference. The 16 concentric circles are equally spaced within a radius of 300 mm.

[0051] The heat dissipation characteristics of the upper electrode having a recess are evaluated using a simulation. In this evaluation, the ratio (temperature ratio) of the increased temperatures of the example model and the comparative example model to the temperature of the reference model at a radial position is used for the evaluation. FIG. 6 is a diagram illustrating an example of the temperature distribution of the shower head of the plasma processing apparatus according to this embodiment. The line G1 in the graph shows the results for the example model. The line G2 shows the results for the comparative example model.

[0052] When the comparative model has recesses around the entire circumference, the thermal resistance between the upper electrode and the cooling plate increases. This reduces the cooling performance of the cooling plate, causing the temperature of the upper electrode to rise. In addition, the temperature rise near the center is large, and the thermal uniformity is poor.

[0053] The embodiment model can suppress the temperature rise and improve the thermal uniformity compared to the comparative example model. By suppressing the temperature rise, the life of the upper electrode can be extended. Furthermore, by improving the thermal uniformity, it is possible to suppress the unevenness of processing performance such as etching rate depending on the location.

[0054] <Abnormal discharge between the upper electrode and the cooling plate> Regarding the number of through holes in the upper electrode relative to one through hole in the cooling plate, an evaluation was made regarding abnormal discharge between the cooling plate and the upper electrode.

[0055] Fig. 7 is a diagram showing an operating state when there are two through holes in the upper electrode for one through hole in the cooling plate. Fig. 8 is a diagram showing an operating state when there are four through holes in the upper electrode for one through hole in the cooling plate. For comparison, Figs. 10 and 11 are diagrams showing an operating state when there is one through hole in the upper electrode for one through hole in the cooling plate. In Figs. 7, 8, 10, and 11, "Error" indicates that an abnormal discharge has been detected.

[0056] As an example of plasma processing conditions according to this embodiment, conditions for etching a silicon oxide film formed on a substrate will be described. The evaluation was performed by performing an etching process in the plasma processing apparatus 1. The evaluation was performed with the pressure in the plasma processing space 10s set to 25 mTorr (=3.3 Pascal) and the set temperature of the substrate support 11 set to 70°C. The evaluation was performed using hexafluoro-1,3-butadiene, oxygen, nitrogen, and argon as processing gases. The flow rates of the hexafluoro-1,3-butadiene, oxygen, nitrogen, and argon used as processing gases were 70 / 40 / 200 / 800 sccm (maximum flow rates).

[0057] The evaluation was performed by supplying a source RF signal with a frequency of 40 MHz and a bias RF signal with a frequency of 400 kHz and a power of 10,000 watts from the power source 30 to the substrate holder 116 .

[0058] In condition A, a pulsed signal having a high level of 4000 watts and a low level of 200 watts was supplied as the source RF signal. In addition, in condition A, a pulsed signal having a high level of -300 volts and a low level of -1000 volts was supplied as the second DC signal.

[0059] In condition B, a pulsed signal with a high level of 4000 watts and a low level of 0 watts was supplied as the source RF signal, and a pulsed signal with a high level of -150 volts and a low level of -1000 volts was supplied as the second DC signal.

[0060] In condition C, a pulsed signal with a high level of 4000 watts and a low level of 0 watts was supplied as the source RF signal, and a pulsed signal with a high level of -300 volts and a low level of -1000 volts was supplied as the second DC signal.

[0061] In condition D, a pulsed signal with a high level of 4000 watts and a low level of 0 watts was supplied as the source RF signal, and a pulsed signal with a high level of -500 volts and a low level of -1000 volts was supplied as the second DC signal.

[0062] In condition E, a pulse signal having a high level of 4000 watts and a low level of 0 watts was supplied as the source RF signal. Also, in condition E, a signal having a constant voltage of −150 volts was supplied as the second DC signal.

[0063] In condition F, a pulse signal having a high level of 4000 watts and a low level of 0 watts was supplied as the source RF signal. Also, in condition F, a signal having a constant voltage of -300 volts was supplied as the second DC signal.

[0064] In condition G, a pulse signal having a high level of 4000 watts and a low level of 0 watts was supplied as the source RF signal. Also, in condition G, a signal having a constant voltage of -500 volts was supplied as the second DC signal.

[0065] Conditions A to G are conditions in which the pulse conditions and applied voltage conditions have been changed. TF represents the flow rate of the process gas (gas flow rate). The gas flow rate is expressed as a percentage of the maximum flow rate, with the maximum flow rate through the device being 100%.

[0066] For comparison, Fig. 10 shows the occurrence of abnormal discharge when the voltage applied to the upper electrode is lowered when there is one through-hole in the upper electrode for each through-hole in the cooling plate. Fig. 11 shows the occurrence of abnormal discharge when the voltage applied to the upper electrode is higher than that in Fig. 10 when there is one through-hole in the upper electrode for each through-hole in the cooling plate.

[0067] 10, in the case where there is one through-hole in the upper electrode for one through-hole in the cooling plate, with the voltage applied to the upper electrode reduced and the gas flow rate TF being 100%, abnormal discharge occurs under conditions C, D and G. Note that for condition D, abnormal discharge also occurs when the gas flow rate TF is 60% and 80%.

[0068] Furthermore, when the voltage applied to the upper electrode is increased, in the case where there is one through-hole in the upper electrode for each through-hole in the cooling plate, abnormal discharge occurs when the gas flow rate TF is 60%, 80% and 100% under conditions B, C and D (FIG. 11). Under condition A, abnormal discharge occurs when the gas flow rate TF is 80% and 100%. Under condition G, abnormal discharge occurs when the gas flow rate TF is 100%.

[0069] When there are two through-holes in the upper electrode for one through-hole in the cooling plate, abnormal discharge occurs when the gas flow rate TF is 100% under conditions A, B, C, D, and G with an increased voltage applied to the upper electrode, as shown in Figure 7. By providing two through-holes in the upper electrode for one through-hole in the cooling plate, the occurrence of abnormal discharge can be suppressed compared to when there is one through-hole in the upper electrode for one through-hole in the cooling plate.

[0070] Furthermore, when there are four through-holes in the upper electrode for one through-hole in the cooling plate, as shown in FIG. 8, abnormal discharge can be suppressed under all conditions.

[0071] FIG. 9 shows the pressure of the process gas at the boundary between the through-hole of the cooling plate and the through-hole of the upper electrode.

[0072] The horizontal axis represents the number of through holes in the upper electrode relative to one through hole in the cooling plate, and the vertical axis represents the pressure of the process gas at the boundary between the through hole in the cooling plate and the through hole in the upper electrode.

[0073] The pressure of the process gas at the boundary between the through hole of the cooling plate and the through hole of the upper electrode decreases as the number of through holes of the upper electrode increases relative to one through hole of the cooling plate. When the pressure of the process gas at the boundary between the through hole of the cooling plate and the through hole of the upper electrode decreases, the density of the process gas decreases, and the occurrence of discharge can be suppressed. Therefore, abnormal discharge between the cooling plate and the upper electrode can be suppressed.

[0074] <Actions and Effects> In the shower head according to this embodiment, the through-holes of the upper electrode are of By having at least two, the cooling plate and the upper very The occurrence of abnormal discharge between the

[0075] Furthermore, in the showerhead according to this embodiment, the through-hole of the cooling plate and the through-hole of the upper electrode are connected via recesses that are spaced apart from each other. By connecting the through-hole of the cooling plate and the through-hole of the upper electrode via the recesses, it is possible to suppress a decrease in the cooling performance of the cooling plate for the upper electrode and to suppress the occurrence of abnormal discharge.

[0076] The through hole 13Ah is an example of a first through hole, and the lower surface 13AS is an example of a first surface. The through holes 13Bh1, 13Bh2, 113Bh1, 113Bh2, 113Bh3, 113Bh4, 213Bh1, 213Bh2, and 213Bh3 are each an example of a second through hole. The upper surfaces 13BS1, 113BS1, and 213BS1 are each an example of a second surface, and the lower surface 13BS2 is an example of a third surface.

[0077] <Modification> In this embodiment, the recess is provided on the upper surface of the upper electrode, but the location of the recess is not limited to the upper electrode. For example, the recess may be provided on the lower surface of the cooling plate, i.e., the surface connected to the upper electrode.

[0078] In this embodiment, examples have been shown in which there are two, three, and four through holes in the upper electrode for one through hole in the cooling plate, but there may be any number of through holes in the upper electrode as long as there are two or more through holes for one through hole in the cooling plate. Sand That is, for one through hole in the cooling plate, there should be at least two through holes in the upper electrode.

[0079] The shower head and plasma processing apparatus according to the present embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The above-described embodiments can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above-described embodiments can be configured in other ways without any contradiction, and can be combined without any contradiction. [Explanation of symbols]

[0080] 1. Plasma processing equipment 10 Plasma Processing Chamber 10s Plasma treatment space 13, 113, 213 Shower head 13A Cooling Plate 13Ah through hole 13AS bottom side 13b Gas diffusion chamber 13B, 113B, 213B upper electrode 13Bg, 113Bg, 213Bg recess 13Bh1, 13Bh2, 113Bh1, 113Bh2, 113Bh3, 113Bh4, 213Bh1, 213Bh2, 213Bh3 Through hole 13BS1, 113BS1, 213BS1 top surface 13BS2 below

Claims

1. 1. A showerhead for supplying a process gas into an interior of a process chamber, comprising: a cooling plate having a gas diffusion chamber and a plurality of first through holes extending from the gas diffusion chamber to a first surface on the processing chamber side and through which the processing gas flows; an upper electrode having a second surface in contact with the first surface of the cooling plate and a third surface forming an inner surface of the processing chamber, the upper electrode having a plurality of second through holes extending from the second surface to the third surface; A plurality of recesses formed on the first surface or the second surface and spaced apart from each other; Equipped with Any one of the plurality of first through holes is connected to at least two of the plurality of second through holes via any one of the plurality of recesses, At least one of the plurality of recesses is formed in an arc shape. Shower head.

2. A showerhead for supplying a process gas into a process chamber, comprising: a cooling plate having a gas diffusion chamber and a plurality of first through holes extending from the gas diffusion chamber to a first surface on the processing chamber side and through which the processing gas flows; an upper electrode having a second surface in contact with the first surface of the cooling plate and a third surface forming an inner surface of the processing chamber, the upper electrode having a plurality of second through holes extending from the second surface to the third surface; A plurality of recesses formed on the first surface or the second surface and spaced apart from each other; Equipped with Any one of the plurality of first through holes is connected to at least two of the plurality of second through holes via any one of the plurality of recesses, At least one of the plurality of recesses is formed in a cross shape. Shower head.

3. The cooling plate is made of aluminum, The upper electrode is formed of silicon. The showerhead according to claim 1 or 2.

4. The showerhead according to any one of claims 1 to 3, Plasma processing equipment.

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