JP2023054556A - Plasma processing device and upper electrode plate - Google Patents

Abstract

To correct fine tilting in plasma processing by changing a structure of an upper electrode plate.SOLUTION: A plasma processing device comprises: a plasma processing chamber; a substrate support unit which is disposed in the plasma processing chamber and includes a lower electrode; a showerhead assembly which is disposed above the substrate support unit and includes an upper electrode plate, in the showerhead assembly, the upper electrode plate including a plurality of gas holes extending to a bottom face of the upper electrode plate and the bottom face of the upper electrode plate including at least one annular groove formed at a position not overlapping the plurality of gas holes in a planar view; a first RF generation unit coupled to the lower electrode or the upper electrode plate; a second RF generation unit coupled to the lower electrode; and a first DC generation unit coupled to the upper electrode plate.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to plasma processing apparatuses and upper electrode plates.

Patent Document 1 discloses a plasma processing apparatus having a lower electrode and an upper electrode. High-frequency power for plasma generation is supplied to the lower electrode from a high-frequency power supply. A negative DC voltage is supplied to the upper electrode from a DC power supply.

JP 2016-181343 A

The technique according to the present disclosure corrects minute tilting in plasma processing by modifying the structure of the upper electrode plate.

A plasma processing apparatus according to one aspect of the present disclosure includes a plasma processing chamber, a substrate support arranged in the plasma processing chamber and including a lower electrode, and a shower arranged above the substrate support and including an upper electrode plate. In the head assembly, the upper electrode plate has a plurality of gas holes extending to a lower surface of the upper electrode plate, and the lower surface of the upper electrode plate is positioned so as not to overlap with the plurality of gas holes in plan view. a showerhead assembly having at least one annular groove formed therein; a first RF generator coupled to said lower electrode or upper electrode plate; and a second RF generator coupled to said lower electrode; a first DC generator coupled to the upper electrode plate.

According to the present disclosure, minute tilting in plasma processing can be corrected by modifying the structure of the upper electrode plate.

1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus; FIG. FIG. 4 is an enlarged cross-sectional view showing a portion of the showerhead assembly and a portion of the substrate support; FIG. 4 is a plan view of the upper electrode plate of the showerhead assembly viewed from below; It is explanatory drawing which shows an electron density, a sheath, and a tilt angle in a comparative example. It is explanatory drawing which shows an electron density, a sheath, and a tilt angle in this embodiment. FIG. 4 is an explanatory diagram showing the relationship between the application position of DC voltage and the change position of electron density. It is sectional drawing which expands and shows an annular groove. FIG. 11 is a bottom plan view of an upper electrode plate of a showerhead assembly in another embodiment;

2. Description of the Related Art In the manufacturing process of semiconductor devices, semiconductor substrates (hereinafter simply referred to as “substrates”) are subjected to various plasma treatments such as etching, film formation, and diffusion. These plasma treatments are performed using, for example, a capacitively coupled plasma (CCP) plasma treatment apparatus.

The plasma processing apparatus disclosed in Patent Document 1 described above is an example of a capacitively coupled plasma processing apparatus, and includes a lower electrode and an upper electrode. A lower electrode is provided in the chamber, and a substrate is placed on the lower electrode. The upper electrode is provided as an upper electrode plate in a showerhead assembly forming at least a portion of the chamber top. Then, a processing gas is supplied into the chamber, and high-frequency power is supplied to the lower electrode or the upper electrode to generate plasma in the chamber, and plasma processing is performed on the substrate by the plasma. Further, by applying a negative DC voltage to the upper electrode, electrons emitted from the upper electrode are accelerated toward the substrate, promoting plasma processing.

Here, for example, when etching is performed as plasma processing, the incident direction of ions in the plasma may be tilted on the substrate, causing tilting in the etched shape, that is, so-called tilting. The tilting changes as the thickness of the sheath changes due to the influence of the electron density distribution on the substrate.

Especially in recent years, as semiconductor devices have become highly integrated and miniaturized, such tilting cannot be ignored even if it is minute. Conventionally, however, no consideration has been given to controlling the electron density on the substrate in order to suppress minute tilting. Therefore, conventional plasma processing leaves room for improvement.

A plasma processing apparatus and an upper electrode plate according to this embodiment will be described below with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<Plasma processing system and plasma processing apparatus>
A configuration example of the plasma processing system will be described below. FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2 . A capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10 , a gas supply section 20 , a power supply 30 and an exhaust system 40 . Further, the plasma processing apparatus 1 includes a substrate support section 11 and a gas introduction section. The gas introduction is configured to introduce at least one process gas into the plasma processing chamber 10 . The gas inlet includes showerhead assembly 13 . A substrate support 11 is positioned within the plasma processing chamber 10 . A showerhead assembly 13 is positioned above the substrate support 11 . In one embodiment, showerhead assembly 13 forms at least a portion of the ceiling of plasma processing chamber 10 . Also, the shower head assembly 13 is supported by the sidewall 10a of the plasma processing chamber 10 via an insulating member (not shown). The plasma processing chamber 10 has a plasma processing space 10 s defined by a showerhead assembly 13 , sidewalls 10 a of the plasma processing chamber 10 and a substrate support 11 . The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas exhaust port for exhausting gas from the plasma processing space. Plasma processing chamber 10 is grounded. Showerhead assembly 13 and substrate support 11 are electrically isolated from the enclosure of plasma processing chamber 10 .

The substrate support portion 11 includes a body portion 111 and a ring assembly 112 . The body portion 111 has a central region 111 a for supporting the substrate W and an annular region 111 b for supporting the ring assembly 112 . A wafer is an example of a substrate W; The annular region 111b of the body portion 111 surrounds the central region 111a of the body portion 111 in plan view. The substrate W is arranged on the central region 111 a of the main body 111 , and the ring assembly 112 is arranged on the annular region 111 b of the main body 111 so as to surround the substrate W on the central region 111 a of the main body 111 . Accordingly, 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. FIG.

In one embodiment, body portion 111 includes base 1110 and electrostatic chuck 1111 . Base 1110 includes a conductive member. A conductive member of the base 1110 can function as a bottom electrode. An electrostatic chuck 1111 is arranged on the base 1110 . The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. Ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be placed on the annular electrostatic chuck or the annular insulating member, or may be placed on both the electrostatic chuck 1111 and the annular insulating member. Also, at least one RF/DC electrode coupled to an RF (Radio Frequency) power source 31 and/or a DC (Direct Current) power source 32, which will be described later, may be arranged in the ceramic member 1111a. In this case, at least one RF/DC electrode functions as the bottom electrode. If a bias RF signal and/or a DC signal, described below, is applied to 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 at least one RF/DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Accordingly, the substrate support 11 includes at least one bottom electrode.

Ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings 113 and at least one cover ring 114 . The edge ring 113 is annularly provided so as to surround the substrate W on the body portion 111 . The cover ring 114 is annularly provided so as to surround the edge ring 113 . The edge ring 113 is formed of a conductive material or an insulating material, for example Si or SiC in the case of a conductive material. Cover ring 114 is formed of an insulating material.

Also, the substrate supporter 11 may include a temperature control module configured to control at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include heaters, heat transfer media, channels 1110a, or combinations thereof. A heat transfer fluid, such as brine or gas, flows through flow path 1110a. In one embodiment, channels 1110 a are formed in base 1110 and one or more heaters are positioned in ceramic member 1111 a of electrostatic chuck 1111 . The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

Showerhead assembly 13 is configured to introduce at least one process gas from gas supply 20 into plasma processing space 10s. The showerhead assembly 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of 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 through a plurality of gas introduction ports 13c. The showerhead assembly 13 also includes at least one upper electrode, such as the upper electrode plate 210 described below. In addition to the showerhead assembly 13, the gas introduction part may include one or more side gas injectors (SGI: Side Gas Injectors) attached to one or more openings formed in the side wall 10a.

Gas supply 20 may include at least one gas source 21 and at least one flow controller 22 . In one embodiment, gas supply 20 is configured to supply at least one process gas from respective gas sources 21 through respective flow controllers 22 to showerhead assembly 13 . Each flow controller 22 may include, for example, a mass flow controller or a pressure controlled flow controller. Additionally, gas supply 20 may include one or more flow modulation devices that modulate or pulse the flow of at least one process gas.

Power supply 30 includes an RF power supply 31 coupled to plasma processing chamber 10 via at least one impedance match circuit. 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. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, RF power source 31 may function as at least part of a plasma generator configured to generate a plasma from one or more process gases in plasma processing chamber 10 . Also, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated in the substrate W, and ion components in the formed plasma can be drawn into the substrate W. FIG.

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

A second RF generator 31b is coupled to the 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 within the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. One or more bias RF signals generated are provided to at least one bottom electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

Power supply 30 may also include a DC power supply 32 coupled to plasma processing chamber 10 . The DC power supply 32 includes a first DC generator 32a, a second DC generator 32b and a third DC generator 32c. In one embodiment, the first DC generator 32a is connected to the at least one bottom electrode and configured to generate a first DC signal. A generated first bias DC signal is applied to at least one bottom electrode. In one embodiment, the second DC generator 32b is connected to the at least one top electrode and configured to generate a second DC signal. The generated second DC signal is applied to at least one top electrode. The second DC generator 32b is also called a substrate DC generator. In one embodiment, the third DC generator 32c is connected to one or more edge rings 113 and configured to generate a third DC signal. The generated third DC signal is applied to one or more edge rings 113 . The third DC generator 32c is also called an edge ring DC generator.

In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one bottom electrode and/or at least one top electrode. The voltage pulses may have rectangular, trapezoidal, triangular, or combinations thereof pulse waveforms. In one embodiment, a waveform generator for generating a sequence of voltage pulses from a DC signal is connected between the first DC generator 32a and the at least one bottom electrode. Therefore, 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 pulse may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses in one cycle. Note that the first and second DC generators 32a and 32b may be provided in addition to the RF power supply 31, and the first DC generator 32a may be provided instead of the second RF generator 31b. good.

The exhaust system 40 may be connected to a gas outlet 10e provided at the bottom of the plasma processing chamber 10, for example. Exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. Vacuum pumps may include turbomolecular pumps, dry pumps, or combinations thereof.

Controller 2 processes computer-executable instructions that cause plasma processing apparatus 1 to perform the various steps described in this disclosure. Controller 2 may be configured to control elements of plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the controller 2 may be included in the plasma processing apparatus 1 . The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented by, for example, a computer 2a. Processing unit 2a1 can be configured to perform various control operations by reading a program from storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2, read from the storage unit 2a2 and executed by the processing unit 2a1. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

<Shower head assembly>
Next, the configuration of the showerhead assembly 13 described above will be described. FIG. 2 is an enlarged cross-sectional view showing a portion of the showerhead assembly 13 and a portion of the substrate support 11. As shown in FIG. FIG. 3 is a bottom plan view of the upper electrode plate 210 of the showerhead assembly 13. FIG.

As shown in FIG. 2, showerhead assembly 13 comprises metal plate 200 and upper electrode plate 210 . The metal plate 200 is laminated on the upper surface side of the upper electrode plate 210 .

Metal plate 200 is made of a metal material, that is, a conductive material. In one embodiment, metal plate 200 is formed of, for example, aluminum. Also, in one embodiment, metal plate 200 is electrically grounded.

Inside the metal plate 200, the gas diffusion chamber 13b described above is formed. The metal plate 200 is formed with a plurality of gas holes 201 extending downward through the gas diffusion chamber 13b to the lower surface. A plurality of gas holes 201 are formed corresponding to gas holes 211 of an upper electrode plate 210, which will be described later.

A lower surface 210a of the upper electrode plate 210 serves as a plasma exposed surface exposed to plasma in the plasma processing space 10s. The upper electrode plate 210 is made of a high purity, low dusting material because it is exposed to plasma and consumed. Also, in one embodiment, the top electrode plate 210 is connected to the second DC generator 32b and is formed of a conductive material. The upper electrode plate 210 is made of Si or SiC, for example, as a material that satisfies these conditions.

The upper electrode plate 210 is formed with a plurality of gas holes 211 extending through the upper electrode plate 210 in the thickness direction, that is, in the vertical direction, to the lower surface 210a. The upper ends of the plurality of gas holes 211 are respectively connected to the gas holes 201 of the metal plate 200, and the plurality of gas holes 211 communicate with the gas diffusion chamber 13b. The lower end of each gas hole 211 on the side of the lower surface 210a serves as the gas introduction port 13c described above. The diameter of the gas hole 201 is uniform along the thickness direction of the upper electrode plate 210, for example. In one embodiment, the upper electrode plate 210 used in the plasma processing apparatus 1 comprises a top surface 210b, a bottom surface 210a, and a plurality of gas holes 211 extending from the top surface 210b to the bottom surface 210a. The lower surface 210a has at least one annular groove 212 formed at a position not overlapping the plurality of gas holes 211 in plan view. The annular groove 212 has a substantially V-shaped or substantially U-shaped shape that widens downward in a side view. The lower end of the annular groove 212 has a width of 2 mm to 10 mm when viewed from the side, and the annular groove 212 has a height of 1 mm or more when viewed from the side.

As shown in FIG. 3 , the plurality of gas holes 211 are arranged at regular intervals on a concentric circle with the lower surface 210a of the upper electrode plate 210 . Also, a plurality of concentric circles in which the plurality of gas holes 211 are arranged are provided in the radial direction of the lower surface 210a.

As shown in FIGS. 2 and 3, the lower surface 210a of the upper electrode plate 210 is formed with at least one annular groove 212. As shown in FIG. In one embodiment, three annular grooves 212 are formed. These annular grooves 212 are formed at positions that do not overlap with the plurality of gas holes 211 in plan view. Each annular groove 212 has a substantially V-shaped or substantially U-shaped shape that widens downward in a side view.

The plurality of gas holes 211 includes a plurality of first gas holes 211a formed along the circumference of the first circle Ra and a plurality of second gas holes 211a formed along the circumference of the second circle Rb. A gas hole 211b is provided. The second circle Rb is provided radially outside the first circle Ra, and the diameter of the second circle Rb is larger than the diameter of the first circle Ra. A first annular groove 212a is formed between the plurality of first gas holes 211a and the plurality of second gas holes 211b.

The multiple gas holes 211 include multiple third gas holes 211c formed along the circumference of the third circle Rc. The third circle Rc is provided radially outside the second circle Rb, and the diameter of the third circle Rc is larger than the diameter of the second circle Rb. A second annular groove 212b is formed between the plurality of second gas holes 211b and the plurality of third gas holes 211c.

The multiple gas holes 211 include multiple fourth gas holes 211d formed along the circumference of the fourth circle Rd. The fourth circle Rd is provided radially outside the third circle Rc, and the diameter of the fourth circle Rd is larger than the diameter of the third circle Rc. A third annular groove 212c is formed between the plurality of third gas holes 211c and the plurality of fourth gas holes 211d.

According to the present embodiment, since at least one annular groove 212 is formed in the bottom surface 210a of the upper electrode plate 210, the surface area of the bottom surface 210a is partially increased compared to the conventional flat bottom surface. can do. Then, when a DC voltage is applied from the second DC generator 32b to the upper electrode plate 210, the DC voltage (DC applied amount) locally increases in the portion where the annular groove 212 is formed, and the electron density locally increases. increase exponentially. Then, the sheath changes around the portion below where the annular groove 212 is formed, and the tilt angle changes. The tilt angle is the inclination (angle) of the etching shape formed by etching with respect to the thickness direction of the substrate W, for example, when the plasma processing is etching. The tilt angle is substantially the same as the inclination of the incident direction of ions to the substrate W with respect to the vertical direction.

As described above, according to the present embodiment, by forming the annular groove 212 in the lower surface 210a of the upper electrode plate 210, minute specific tilting control on the substrate W becomes possible. Thereby, the uniformity of the electron density distribution on the substrate W is improved.

Moreover, since it is only necessary to form the annular groove 212 in the lower surface 210a of the upper electrode plate 210, the thickness of the upper electrode plate 210 can be kept constant and reduced. As a result, it is possible to enjoy the above-described effect of improving the uniformity of the electron density distribution at low cost.

The effect of this embodiment will be described below with reference to a comparative example. The comparative example is an example in which the annular groove 212 is not formed in the lower surface 210a of the upper electrode plate 210 and the lower surface 210a is flat.

FIG. 4 is an explanatory diagram showing electron density, sheath and tilt angles in a comparative example. In FIG. 4, the dotted line indicates the sheath. Note that the dotted line sheath is almost the same as the tilt angle.

但し、ε_０：プラズマの真空率、Ｔ_ｅ：電子温度、Ｎ_ｅ：電子密度、Ｖ_ｄｃ：セルフバイアス電圧である。 Here, the sheath thickness can be calculated, for example, by the following formula (1).

where ε ₀ : plasma vacuum rate, T _e : electron temperature, N _e : electron density, and V _dc : self-bias voltage.

In such a comparative example, for example, the electron density on the edge region of the substrate W changes. Then, based on the above formula (1), the sheath thickness at the same position changes as shown in FIG. 4, and the tilt angle changes. As a result, local tilting occurs on the substrate.

FIG. 5 is an explanatory diagram showing the electron density and the sheath and tilt angles in this embodiment. Also in FIG. 5, the dotted lines indicate the sheath and tilt angles. In this embodiment, at least one annular groove 212 is formed in the lower surface 210a of the upper electrode plate 210 for the edge region of the substrate W, ie, the region where the electron density changed in the comparative example.

In such a case, as shown in FIG. 5A, in the portion where the annular groove 212 is formed, the amount of DC applied locally increases, and many electrons flow from the annular groove 212 toward the substrate W (see FIG. 5A). downward thick arrow). As a result, electrons flow in the left-right direction directly below the portion where the annular groove 212 is formed, and the electron density locally increases in the left-right direction (thick arrows in the left-right direction in FIG. 5). When the electron density is controlled in this way, the sheath can be flattened around the portion below where the annular groove 212 is formed as shown in FIG. Therefore, minute tilting on the substrate W can be suppressed.

Here, the present inventors verified the phenomenon that the location where the DC voltage is applied and the location where the electron density changes are shifted, as indicated by the thick arrows in FIG. FIG. 6 shows the verification results. In FIG. 6, the vertical axis indicates the electron density, and the horizontal axis indicates the radial position on the substrate W. In FIG. In this verification, different voltages V1 to V5 were applied to the positions indicated by the downward arrows in FIG. 6 (for example, the outer periphery of the substrate W). As a result, the electron density peak shifted inward in both cases. From this verification, it can be seen that the change position of the electron density is shifted from the DC voltage application position.

Next, preferred dimensions of the annular groove 212 on the lower surface 210a of the upper electrode plate 210 will be described. FIG. 7 is an enlarged cross-sectional view showing the annular groove 212 (the first annular groove 212a, the second annular groove 212b, and the third annular groove 212c).

The lower end width A of the annular groove 212 is preferably 2 mm to 10 mm. Considering the thickness of the sheath, the bottom width A is preferably 2 mm or more. Moreover, when the width A of the lower end exceeds 10 mm, the surface area of the lower surface 210a can be increased by increasing the number of the annular grooves 212 .

A height B of the annular groove 212 is preferably 1 mm or more. A sheath can be formed if the height B is 1 mm or more.

When a plurality of annular grooves 212a, 212b, and 212c are formed in the radial direction, the interval C between adjacent annular grooves 212a and 212b and the annular grooves 212b and 212b The distance C between each is preferably between 2 mm and 5 mm. When the interval C is 2 mm to 5 mm, even if the upper electrode plate 210 wears, the adjacent annular grooves 212a and 212b and the adjacent annular grooves 212b and 212b do not reach each other.

<Other embodiments>
Although at least one annular groove 212 is formed in the edge region of the lower surface 210a of the upper electrode plate 210 in the above embodiment, it may be formed in the central region (near the center) of the lower surface 210a. The edge region of the lower surface 210a is a region that overlaps with the edge region of the substrate W on the substrate supporting portion 11 in plan view. The central region of the lower surface 210a is a region that overlaps with the central region (near the center) of the substrate W on the substrate supporting portion 11 in plan view. For example, when a slight tilting occurs in the central region of the substrate W, the annular groove 212 is formed in the central region of the lower surface 210a. The point is that the annular groove 212 should be formed in accordance with the position where the peculiar tilting occurs.

In the above embodiment, the first annular groove 212a and the second annular groove 212a are interposed between the first gas hole 211a, the second gas hole 211b, the third gas hole 211c, and the fourth gas hole 211d, respectively. Although the groove 212b and the third annular groove 212c are formed, the position of the annular groove 212 is not limited to this. For example, as shown in FIG. 8, a plurality of first annular grooves 212a may be formed between the first gas holes 211a and the second gas holes 211b. The arrangement of the annular groove 212 can be arbitrarily designed so that it does not overlap the gas holes 211 .

In the above embodiments, the annular groove 212 has a substantially V-shaped or substantially U-shaped shape when viewed from the side, but the cross-sectional shape is not limited thereto. For example, the cross-sectional shape of the annular groove 212 may be circular or polygonal. If the surface area of the lower surface 210a can be increased, the same effects as those of the above embodiment can be obtained.

<Other effects of the embodiment>
In the above embodiments, the edge ring 113 is connected to the third DC generator 32c. In this case, the sheath on the outer edge of the substrate W can be controlled by applying a DC voltage to the edge ring 113 from the third DC generator 32c. The outer edge of the substrate W is in the range of 5 mm to 10 mm from the outer edge of the substrate W, for example.

On the other hand, the region where the electron density is controlled by the annular groove 212 to control the sheath is the region inside the outer edge of the substrate W. FIG. Therefore, the electron density control region by the annular groove 212 and the electron density control region by the edge ring 113 are different.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The embodiments described above may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

Reference Signs List 1 plasma processing apparatus 10 plasma processing chamber 11 substrate support 13 showerhead assembly 31a first RF generator 31b second RF generator 32b second DC generator 210 upper electrode plate 210a lower surface 211 gas hole 212 annular groove 1110 Base W Substrate

Claims (15)

a plasma processing chamber;
a substrate support disposed within the plasma processing chamber and including a bottom electrode;
a showerhead assembly disposed above the substrate support and including an upper electrode plate having a plurality of gas holes extending to a lower surface of the upper electrode plate; a showerhead assembly, wherein the bottom surface has at least one annular groove formed at a position not overlapping with the plurality of gas holes in plan view;
a first RF generator coupled to the lower electrode or upper electrode plate;
a second RF generator coupled to the bottom electrode;
a first DC generator coupled to the upper electrode plate. 2. The plasma processing apparatus according to claim 1, wherein said annular groove has a substantially V-shape or substantially U-shape whose width increases downward in a side view. 3. The plasma processing apparatus according to claim 1, wherein the lower end of said annular groove has a width of 2 mm to 10 mm in side view. 4. The plasma processing apparatus according to claim 1, wherein said annular groove has a height of 1 mm or more when viewed from the side. The plasma processing apparatus according to any one of claims 1 to 4, wherein said at least one annular groove has a plurality of annular grooves. 6. The plasma processing apparatus according to claim 5, wherein an interval between two adjacent annular grooves among said plurality of annular grooves is 2 mm to 5 mm. 7. The plasma processing apparatus according to claim 1, wherein said annular groove is formed in an edge region of the lower surface of said upper electrode plate in plan view. 7. The plasma processing apparatus according to claim 1, wherein said annular groove is formed near the center of the lower surface of said upper electrode plate in plan view. the substrate support includes a body having a substrate support surface and at least one edge ring disposed on the body to surround the substrate on the substrate support surface;
The plasma processing apparatus of any one of claims 1-8, further comprising a second DC generator coupled to the at least one edge ring. The plasma processing apparatus according to any one of claims 1 to 9, wherein said upper electrode plate is made of Si or SiC. The plurality of gas holes are
a plurality of first gas holes formed along the circumference of the first circle;
a plurality of second gas holes formed along the circumference of a second circle having a diameter larger than that of the first circle;
The plasma processing apparatus according to any one of claims 1 to 10, wherein said at least one annular groove has a first annular groove formed between said first circle and said second circle. . the plurality of gas holes have a plurality of third gas holes formed along the circumference of a third circle having a diameter larger than the diameter of the second circle;
12. The plasma processing apparatus of claim 11, wherein said at least one annular groove comprises a second annular groove formed between said second circle and said third circle. the plurality of gas holes have a plurality of fourth gas holes formed along the circumference of a fourth circle having a diameter larger than the diameter of the third circle;
13. The plasma processing apparatus of claim 12, wherein said at least one annular groove comprises a third annular groove formed between said third circle and said fourth circle. The plurality of gas holes are
a plurality of first gas holes formed along the circumference of the first circle;
a plurality of second gas holes formed along the circumference of a second circle having a diameter larger than that of the first circle;
Plasma according to any one of the preceding claims, wherein said at least one annular groove comprises a plurality of first annular grooves formed between said first circle and said second circle. processing equipment. An upper electrode plate for use in a plasma processing apparatus, comprising:
the top surface and
the underside;
a plurality of gas holes extending from the upper surface to the lower surface;
the lower surface has at least one annular groove formed at a position that does not overlap with the plurality of gas holes in plan view;
The annular groove has a substantially V-shaped or substantially U-shaped shape in which the width increases downward in a side view,
The lower end of the annular groove has a width of 2 mm to 10 mm in side view,
The upper electrode plate, wherein the annular groove has a height of 1 mm or more in a side view.

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