Substrate processing apparatus

Abstract

To provide a plasma processing apparatus and a gas supply method for controlling in-plane uniformity of plasma processing.SOLUTION: A plasma processing apparatus comprises: a plasma processing chamber having a substrate support part configured to support a substrate; a showerhead having a plurality of gas inlets configured to introduce a gas into respective regions within the plasma processing chamber; a gas supply part configured to supply the gas to a plurality of gas inlets; a plasma generation part configured to generate a plasma of the gas; and a control part configured to control at least the gas supply. The gas supply part includes a gas unit configured to supply a common gas to the plurality of gas introduction parts, and an injection unit configured to supply an injection gas to each gas introduction part selected from the plurality of gas introduction pars. The control part controls the injection unit to supply two or more kinds of the injection gas to two different gas introduction parts.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a substrate processing apparatus equipped with a showerhead having a first gas inlet that introduces gas into a center region of the chamber, a second gas inlet that introduces gas into an edge region of the chamber, and a third gas inlet that introduces gas into a region outside the second gas inlet. It also discloses that the first and second gas inlets introduce a process gas into the chamber. It also discloses that the third gas inlet switches between the process gas and the additional gas and introduces them into the chamber using a switching valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-117477 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a plasma processing apparatus and a gas supply method for controlling the in-plane uniformity of plasma processing. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, there is provided a plasma processing apparatus comprising: a plasma processing chamber having a substrate support configured to support a substrate; a showerhead having a plurality of gas inlets configured to introduce gas into each region within the plasma processing chamber; a gas supply unit configured to supply gas to the plurality of gas inlets; a plasma generation unit configured to generate plasma of the gas; and a controller configured to control at least the gas supply unit, wherein the gas supply unit has a gas unit configured to supply a common gas to the plurality of gas inlets and an injection unit configured to supply an injection gas to a selected one of the plurality of gas inlets, and the controller controls the injection unit to supply two or more types of the injection gas to two different gas inlets. [Effects of the Invention]

[0006] According to one aspect, it is possible to provide a plasma processing apparatus and a gas supply method for controlling the in-plane uniformity of plasma processing. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an example of a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. [Figure 2] FIG. 2 is a diagram illustrating an example of a configuration of a gas supply unit. [Figure 3] 10A and 10B are diagrams showing an example of a substrate processing result using a plasma processing apparatus having a gas supply unit. [Figure 4] FIG. 10 is a diagram showing an example of a substrate processing result. [Figure 5] 1 is an example of a graph of normalized etch rate. [Figure 6] 1 is a schematic diagram illustrating an example of a time chart for explaining an etching process. DETAILED DESCRIPTION OF THE INVENTION

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] An example of the configuration of a plasma processing system will be described below: Fig. 1 is an example of a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus.

[0010] The plasma processing system includes a capacitively coupled plasma processing device 1 and a controller 2. The capacitively coupled plasma processing device 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing device 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within 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 portion of the 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 process gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space 10s. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically isolated from the plasma processing chamber 10 enclosure.

[0011] 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 called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0012] 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 (Radio Frequency) power supply 31 and / or a DC (Direct Current) power supply 32 (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 (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 the lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0013] 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.

[0014] 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 to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 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.

[0015] 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 (13a1 to 13a3), at least one gas diffusion chamber 13b (13b1 to 13b3), and multiple gas inlets 13c (13c1 to 13c3). 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.

[0016] 1 includes a gas inlet portion 51, a gas inlet portion 52, and a gas inlet portion 53. The gas inlet portion 51 introduces gas into a central region (center region) of the substrate W in the plasma processing chamber 10. The gas inlet portion 52 introduces gas into a region (intermediate region) outside the gas inlet portion 51. The gas inlet portion 53 introduces gas into a region (edge ​​region) outside the gas inlet portion 52. The gas inlet portion 51, the gas inlet portion 52, and the gas inlet portion 53 are concentrically arranged.

[0017] The gas diffusion chamber 13b includes a gas diffusion chamber 13b1, a gas diffusion chamber 13b2, and a gas diffusion chamber 13b3.

[0018] Gas diffusion chamber 13b1 is connected to gas supply port 13a1 and multiple gas inlets 13c1 so that gas can flow through them. Gas introduction section 51 is configured to include gas supply port 13a1, gas diffusion chamber 13b1, and multiple gas inlets 13c1. Gas diffusion chamber 13b2 is connected to gas supply port 13a2 and multiple gas inlets 13c2 so that gas can flow through them. Gas introduction section 52 is configured to include gas supply port 13a2, gas diffusion chamber 13b2, and multiple gas inlets 13c2. Gas diffusion chamber 13b3 is connected to gas supply port 13a3 and multiple gas inlets 13c3 so that gas can flow through them. Gas introduction section 53 is configured to include gas supply port 13a3, gas diffusion chamber 13b3, and multiple gas inlets 13c3.

[0019] The shower head 13 also includes at least one upper electrode. In addition to the shower head 13, the gas introduction part may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0020] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include one or more flow modulation devices to modulate or pulse the flow rate of the at least one process gas.

[0021] The power supply 30 includes an RF power supply 31 coupled to the plasma processing 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 from at least one process gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of a plasma generating unit configured to generate a plasma from one or more process gases in the plasma processing chamber 10. In addition, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0022] 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.

[0023] 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.

[0024] 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 at least one lower electrode and configured to generate a first DC signal. The generated first bias 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.

[0025] 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 lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof pulse waveform. 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.

[0026] 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 regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0027] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the control unit 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 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. The program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 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 processing unit 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 processing apparatus 1 via a communication line such as a local area network (LAN).

[0028] Next, the gas supply unit 20 will be further described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the configuration of the gas supply unit 20.

[0029] The gas supply unit 20 includes a gas source 21, a gas unit 210 having a flow rate controller 22 (213, 223), an injection unit 220, a flow splitter 230, and a valve 240.

[0030] The gas source 21 includes a plurality of gas sources 21a to 21e. In the following description, the plasma processing apparatus 1 is a plasma etching apparatus that etches an SiO2 film formed on a substrate W, and the gas source 21a supplies O2 gas, the gas source 21b supplies NF3 gas, the gas source 21c supplies CH2F2 gas, the gas source 21d supplies C4F8 gas, and the gas source 21d supplies C4F6 gas.

[0031] The gas unit 210 receives gases from the gas sources 21 (21a to 21e), selects a gas to be supplied to the flow splitter 230, and adjusts the flow rate of the selected gas.

[0032] Specifically, the gas unit 210 includes a valve 211, a valve 212, a flow rate controller 213, a valve 214, gas flow paths 301 (301a to 301e), and a gas flow path 302.

[0033] A gas flow path 301 (301a to 301e) is provided for each gas type of the gas source 21. In the example shown in FIG. 2, five gas flow paths 301 (301a to 301e) are provided corresponding to the gas types of the gas sources 21. The upstream side of each gas flow path 301 (301a to 301e) is connected to each gas source 21 (21a to 21e). In each gas flow path 301 (301a to 301e), a valve 211, a valve 212, a flow rate controller 213 (22), and a valve 214 are provided in this order from the gas source 21 side. The downstream sides of the gas flow paths 301 (301a to 301e) join together and are connected to a gas flow path 302. The downstream side of the gas flow path 302 is connected to a flow splitter 230.

[0034] Valve 211 is an on-off valve for opening and closing gas flow path 301. Valves 212 and 214 are on-off valves used to select a gas to be supplied to flow splitter 230, with valve 212 being provided upstream of flow rate controller 213 and valve 214 being provided downstream of flow rate controller 213. The flow rate controller 213 can be, for example, a mass flow controller or a pressure-controlled flow rate controller.

[0035] With this configuration, the control unit 2 can select a gas to be supplied to the flow splitter 230 by controlling the opening and closing of the valves 212 and 214. Furthermore, the control unit 2 can adjust the flow rate of the selected gas by controlling the flow rate controller 213. Then, the gas selected and flow rate adjusted by the gas unit 210 (or a mixed gas if multiple gases are selected) is supplied to the flow splitter 230. In the following description, the gas supplied from the gas unit 210 to the flow splitter 230 is also referred to as a common gas (or a main gas).

[0036] The flow splitter 230 distributes and supplies the common gas supplied from the gas unit 210 (gas flow path 302) to the gas flow paths 303 (303C, 303M, 303E).

[0037] A gas flow path 303 (303C, 303M, 303E) is provided for each divided gas inlet portion of the shower head 13. In the example shown in FIG. 2, the shower head 13 has three divided gas inlets (gas inlet portion 51, gas inlet portion 52, gas inlet portion 53), and three systems of gas flow paths 303 (303C, 303M, 303E) are provided corresponding to the number of gas inlets. The gas flow paths 303 (303C, 303M, 303E) are provided with valves 240. The valves 240 are on-off valves for opening and closing the gas flow paths 303. The downstream side of the gas flow path 302 is connected to the gas supply port 13a of the shower head 13.

[0038] That is, the downstream side of gas flow path 303C is connected to gas supply port 13a1, the downstream side of gas flow path 303M is connected to gas supply port 13a2, and the downstream side of gas flow path 303E is connected to gas supply port 13a3.

[0039] With this configuration, the common gas split by the flow splitter 230 is supplied to the gas supply ports 13a1 to 13a3 of the shower head 13 via the gas flow passage 303.

[0040] Therefore, the common gas selected and flow rate adjusted in the gas unit 210 is introduced into the center region, intermediate region and edge region in the plasma processing chamber 10 from the gas introduction section 51, the gas introduction section 52 and the gas introduction section 53.

[0041] The injection unit 220 receives gases from the gas sources 21 (21a to 21e), independently selects gases (injected gases) to be supplied to the gas flow path 303C (gas supply port 13a1), the gas flow path 303M (gas supply port 13a2), and the gas flow path 303E (gas supply port 13a3), and adjusts the flow rates of the selected gases.

[0042] Specifically, the injection unit 220 includes a valve 221, a valve 222, a flow rate controller 223, a valve 224, gas flow paths 304 (304a to 304e), and gas flow paths 305 (305C, 305C, 305E).

[0043] 2, five gas flow paths 304 (304a to 304e) are provided corresponding to the gas types of the gas source 21. The upstream side of each gas flow path 304 (304a to 304e) is connected to a corresponding gas flow path 301 (301a to 301e) between the valve 211 and the valve 212. The gas flow paths 304 (304a to 304e) are provided with a valve 221.

[0044] Further, downstream of the valve 221, the gas flow path 304 (304a to 304e) branches into three paths corresponding to the number of gas flow paths 303 (303C, 303M, 303E) (in other words, the number of partitioned gas inlets). The gas flow path 304a branches into a gas flow path 304aC, a gas flow path 304aM, and a gas flow path 304aE. The branched gas flow paths 304aC, 304aM, and 304aE are provided with a valve 222, a flow rate controller 223 (22), and a valve 224 in this order from the valve 221 side.

[0045] Similarly, the gas flow paths 304b to 304e are branched into three paths downstream of the valve 221, and in each of the branched gas flow paths, a valve 222, a flow rate controller 223 (22), and a valve 224 are provided in this order from the valve 221 side.

[0046] The downstream side of the gas flow path 304aC is joined with a gas flow path 304bC branched from the gas flow path 304b, a gas flow path 304cC branched from the gas flow path 304c, a gas flow path 304dC branched from the gas flow path 304d, and a gas flow path 304eC branched from the gas flow path 304e, and is connected to a gas flow path 305C. The downstream side of the gas flow path 305C is connected to a gas flow path 303C between the flow splitter 230 and the valve 240.

[0047] Similarly, the downstream side of gas flow path 304aM is joined with gas paths branching from gas flow path 304b, gas paths branching from gas flow path 304c, gas paths branching from gas flow path 304d, and gas paths branching from gas flow path 304e, and is connected to gas flow path 305M. The downstream side of gas flow path 305M is connected to gas flow path 303M between the flow splitter 230 and the valve 240. The downstream side of gas flow path 304aE is joined with gas paths branching from gas flow path 304b, gas paths branching from gas flow path 304c, gas paths branching from gas flow path 304d, and gas paths branching from gas flow path 304e, and is connected to gas flow path 305E. The downstream side of gas flow path 305E is connected to gas flow path 303E between the flow splitter 230 and the valve 240.

[0048] Valve 221 is an on-off valve for opening and closing gas flow path 304. Valves 222 and 224 are on-off valves used to independently select gases to be supplied to gas flow path 303C (gas supply port 13a1), gas flow path 303M (gas supply port 13a2), and gas flow path 303E (gas supply port 13a3). Valve 222 is provided upstream of flow rate controller 223, and valve 224 is provided downstream of flow rate controller 223. For example, a mass flow controller or a pressure-controlled flow rate controller can be used as flow rate controller 223. The number of flow rate controllers 223 provided is 15 in FIG. 2, which is the product of the types of gases supplied to injection unit 220 (five in FIG. 2) and the number of gas flow paths 303 (in other words, the number of partitioned gas introduction sections; three in FIG. 2).

[0049] With this configuration, the control unit 2 can independently select the gases to be supplied to the gas flow path 303C (gas supply port 13a1), the gas flow path 303M (gas supply port 13a2), and the gas flow path 303E (gas supply port 13a3) by controlling the opening and closing of the valves 222 and 224. The control unit 2 can also adjust the flow rates of the selected gases by controlling the flow rate controller 223. The gases selected and flow-rate-adjusted for each of the gas introduction ports 51-53 by the injection unit 220 (or a mixed gas if multiple gases are selected) are then supplied to the gas flow paths 303C, 303M, and 303E corresponding to the gas introduction ports 51-53. In other words, gases can be individually injected into the gases flowing through the gas flow paths 303C, 303M, and 303E. In the following description, the gas injected from the injection unit 220 into the common gas flowing through the gas flow passages 303 (303C, 303M, 303E) is also referred to as an injected gas.

[0050] 2, the gas source 21 supplies five gases (gas sources 21a to 21e), but the number of gases supplied is not limited to five and may be two or more. For example, when etching an SiO2 film, the gas supplied by the gas source 21 may be any of CF4, C4F6, C4F8, C3F8, CH2F2, CHF3, NF3, HBr, Cl2, N2, O2, CO, CO2, Ar, Kr, and the like.

[0051] 1 and 2 have been described as being divided into three gas inlets (gas inlets 51 to 53), but this is not limited thereto and may be two or more. Furthermore, the number of gas flow paths 301 (301a to 301e) in the gas unit 210 (five in FIG. 2) and the number of gas flow paths 304 (304a to 304e) in the injection unit 220 (five in FIG. 2) have been described as being equal to each other, but this is not limited thereto and may be different. Specifically, the gas source 21 may supply only some of the gases supplied to the gas unit 210 to the injection unit 220. Specifically, the injection unit 220 may not be provided with a gas flow path 304 corresponding to a gas used only as a common gas. This reduces the number of components, such as the flow rate controller 223.

[0052] 3 is a schematic diagram illustrating in-plane uniformity control of substrate processing using a plasma processing apparatus 1 having a gas supply unit 20. In FIG. 3, a substrate W supported by a substrate support unit 11 is shown, and the positions of gas inlet units 51 to 53 of a shower head 13 arranged opposite the substrate W are indicated by two-dot chain lines.

[0053] The control unit 2 controls the injection unit 220 to introduce, for example, a first injection gas into the plasma processing space 10s through the gas introduction unit 51 and a second injection gas into the plasma processing space 10s through the gas introduction unit 52. In the example shown in FIG. 3, no injection gas is introduced through the gas introduction unit 53. In this control, the gas unit 210 is controlled to introduce a common gas into the plasma processing space 10s through the gas introduction units 51 to 53. An example of the distribution of the first injection gas on the surface of the substrate W is shown by a solid line. An example of the distribution of the second injection gas on the surface of the substrate W is shown by a dashed line.

[0054] In this way, gas supply unit 20 can inject any gas into any location (gas inlet units 51 to 53) in any amount, thereby improving controllability of in-plane uniformity in substrate processing and widening the process window.

[0055] Next, an example of a substrate processing result using the plasma processing apparatus 1 having the gas supply unit 20 will be described with reference to Figures 4 and 5. Figure 4 is a diagram showing an example of a substrate processing result using the plasma processing apparatus 1 having the gas supply unit 20. Here, the gas source 21 supplies O gas, CH gas, C gas, and C gas, and the plasma processing apparatus 1 performs a plasma etching process on an SiO film formed on the substrate W.

[0056] In the row indicated by "Main CxHyFz," "On" indicates that CH2F2 gas is supplied from the gas unit 210 to the gas inlets 51 to 53 via the flow splitter 230. In the row indicated by "Main O2," "On" indicates that O2 gas is supplied from the gas unit 210 to the gas inlets 51 to 53 via the flow splitter 230. That is, (a) to (f) of FIG. 4 indicate that CH2F2 gas and O2 gas are supplied as common gases.

[0057] The row indicated by "Inj. C4F8" indicates that C4F8 gas is supplied from the injection unit 220 to a gas inlet selected from the gas inlets 51-53. The row indicated by "Inj. C4F6" indicates that C4F6 gas is supplied from the injection unit 220 to a gas inlet selected from the gas inlets 51-53. Furthermore, "C" indicates that the injection gas is injected into the gas inlet 51 (gas flow path 303C). "M" indicates that the injection gas is injected into the gas inlet 52 (gas flow path 303M). "E" indicates that the injection gas is injected into the gas inlet 53 (gas flow path 303E). That is, (b) to (f) of FIG. 4 indicate that C4F8 gas and C4F6 gas are supplied as injection gases. Note that (a) of FIG. 4 indicates that no injection gas is used and only a common gas is supplied.

[0058] Specifically, in (b), C4F8 gas and C4F6 gas were supplied as injection gases to gas inlet 51 (gas flow path 303C). In (c), C4F8 gas and C4F6 gas were supplied as injection gases to gas inlet 52 (gas flow path 303M). In (d), C4F8 gas and C4F6 gas were supplied as injection gases to gas inlet 53 (gas flow path 303E). In (e), C4F8 gas was supplied as injection gas to gas inlet 51 (gas flow path 303C), and C4F6 gas was supplied as injection gas to gas inlet 53 (gas flow path 303E). In (f), C4F8 gas was supplied as injection gas to gas inlet 52 (gas flow path 303M), and C4F6 gas was supplied as injection gas to gas inlet 53 (gas flow path 303E).

[0059] 4, the upper graph of the two graphs shows the etching rate. In this graph, the horizontal axis shows the radial position [mm] of the substrate W, with 0 [mm] indicating the center of the substrate W. The vertical axis shows the etching rate. Here, the etching rate is shown to increase upward.

[0060] In addition, in Figure 4, the lower graph of the two graphs, upper and lower, shows the etching rate normalized with the etching rate of (a) without using injection gas as 1, as a solid line. The normalized result of (a) is also shown as a dashed line. That is, the lower graph shows the change in etching rate when injection gas is used compared to when injection gas is not used. In this graph, the horizontal axis indicates the radial position of the substrate W, with 0 [mm] indicating the center of the substrate W. The vertical axis indicates the etching rate. Here, the illustration is such that the etching rate increases toward the top.

[0061] Fig. 5 is an example of a graph in which graphs of etching rates (lower graphs) normalized by setting the etching rate in Fig. 4(a) without using injected gas as 1 are superimposed on one graph and the vertical axis is enlarged in Fig. 4(d) to (f). Fig. 4(d) is shown by a dashed line, Fig. 4(e) is shown by a solid line, and Fig. 4(f) is shown by a dashed line.

[0062] As shown in (b) to (d) of Figure 4, the plasma processing apparatus 1 having the gas supply unit 20 can supply two types of injection gases (C4F8 gas, C4F6 gas) to the same gas inlet. Also, as shown in (e) to (f) of Figure 4, the plasma processing apparatus 1 having the gas supply unit 20 can supply two types of injection gases (C4F8 gas, C4F6 gas) to different gas inlet. In other words, the type and flow rate of the injection gas supplied to each gas inlet can be made different for each gas inlet.

[0063] 4(d) to 4(f) and FIG. 5, the position where the normalized etching rate decreases varies depending on the gas inlet for supplying the C4F8 gas. When C4F8 gas is supplied to the gas inlet 51 (gas flow path 303C), the normalized etching rate decreases in the center region of the substrate W (see the solid arrow in FIG. 5). When C4F8 gas is supplied to the gas inlet 52 (gas flow path 303M), the normalized etching rate decreases in the middle region of the substrate W (see the dashed arrow in FIG. 5). When C4F8 gas is supplied to the gas inlet 53 (gas flow path 303E), the normalized etching rate decreases in the edge region of the substrate W (see the dashed arrow in FIG. 5).

[0064] In this way, the plasma processing apparatus 1 having the gas supply unit 20 can switch the position of the gas inlet that supplies the C4F8 gas. As shown in Figure 5, the state in which the C4F8 gas is supplied to the gas inlet 53 (gas flow path 303E) (see Figure 4(d)) is changed to the state in which the C4F8 gas is supplied to the gas inlet 51 (gas flow path 303C) (see Figure 4(e)) or the state in which the C4F8 gas is supplied to the gas inlet 52 (gas flow path 303M) (see Figure 4(f)). This allows fine adjustment of the in-plane uniformity or controllability of the etching rate.

[0065] 4 and 5, CH2F2 gas supplied as a common gas is used for etching, and C4F8 gas, which is used as an example of an injection gas, serves to reduce the etching rate. Therefore, C4F8 gas can reduce bowing of recesses when forming a pattern of recesses such as holes on the substrate W.

[0066] Next, an etching process in which two or more steps are performed in multiple cycles in a plasma etching process will be described. Fig. 6 is a schematic diagram of an example of a time chart illustrating the etching process.

[0067] In the etching process shown in FIG. 6, a first step S1 (for example, a protective film deposition step) and a second step S2 (for example, an etching step) are repeated multiple times.

[0068] In the first step S1, for example, a first injection gas is supplied to gas introduction unit 51 (gas flow path 303C) and gas introduction unit 53 (gas flow path 303E), and a second injection gas is supplied to gas introduction unit 53 (gas flow path 303E). The flow rate of the first injection gas supplied to gas introduction unit 53 (gas flow path 303E) is set to be smaller than the flow rate of the first injection gas supplied to gas introduction unit 51 (gas flow path 303C).

[0069] In the second step S2, for example, a first injection gas is supplied to gas introduction unit 51 (gas flow path 303C) and gas introduction unit 52 (gas flow path 303M), and a second injection gas is supplied to gas introduction unit 51 (gas flow path 303C) and gas introduction unit 52 (gas flow path 303M). The flow rate of the first injection gas supplied to gas introduction unit 51 (gas flow path 303C) is set to be less than the flow rate of the first injection gas supplied to gas introduction unit 52 (gas flow path 303M). The flow rate of the second injection gas supplied to gas introduction unit 52 (gas flow path 303M) is set to be less than the flow rate of the second injection gas supplied to gas introduction unit 51 (gas flow path 303C).

[0070] In this way, the plasma processing apparatus 1 having the gas supply part 20 can switch and control the type and flow rate of the injection gas supplied from the injection unit 220 to each of the gas introduction parts 51 to 53 in each step.

[0071] Furthermore, the injection unit 220 supplies the injection gas to the gas flow passages 303 (303C, 303M, 303E) that are downstream of the common gas flow splitter 230 and closer to the shower head 13. This improves the response of switching the gases supplied from the gas introduction parts 51 to 53 into the plasma processing space 10s.

[0072] For example, a step of supplying C4F8 gas to the gas inlet 53 (gas flow path 303E) shown in Fig. 4(d) and a step of supplying C4F8 gas to the gas inlet 51 (gas flow path 303C) shown in Fig. 4(e) are switched at high speed and repeated multiple times. This makes it possible to suppress bowing of the recesses formed in the center region of the substrate W while maintaining the shape of the recesses formed in the edge region of the substrate W.

[0073] The above describes embodiments of the plasma processing system, but the present disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure as described in the claims. [Explanation of symbols]

[0074] W substrate 1. Plasma processing equipment 2. Control Unit 10 Plasma Processing Chamber 11 Substrate support 13. Shower head 20 Gas supply unit 21 Gas Source 21a~21e Gas Source 22,213,223 Flow Controller 30 power supply 40 Exhaust system 210 Gas Unit 211,212,214,221,222,224,240 Valves 220 injection unit 230 Flow Splitter 301~305 Gas flow path 51~53 Gas inlet

Claims

1. a plasma processing chamber having a substrate support configured to support a substrate; a showerhead having a plurality of gas inlets configured to respectively introduce gases into respective regions within the plasma processing chamber; a gas supply unit configured to supply gas to the plurality of gas inlets; a plasma generating unit configured to generate plasma of the gas; a control unit configured to control at least the gas supply unit, The gas supply unit a gas unit configured to supply a common gas to the plurality of gas inlets; a flow splitter configured to distribute the common gas supplied from the gas unit and supply it to the plurality of gas inlets; a valve disposed in a gas flow path between the flow splitter and the plurality of gas inlets; an injection unit configured to supply an injection gas to a selected one of the gas introduction parts; the injection unit is connected to a gas flow path between the flow splitter and the valve; The control unit controlling the injection unit to supply two or more types of injection gases to two different gas inlets; Plasma processing equipment.

2. The injection unit comprises: a plurality of first gas flow paths branching from the gas unit; a plurality of second gas flow paths, one of which is connected to at least one of the plurality of first gas flow paths and the other of which includes a branch portion; a third gas flow path connected to the branch portion; a flow rate controller disposed in all of the plurality of first gas flow paths and the third gas flow path; The plasma processing apparatus according to claim 1 .

3. a confluence of the plurality of first gas flow paths and a confluence of the third gas flow path, The plasma processing apparatus according to claim 2 .

4. The injection unit comprises: the first gas flow path further includes an on-off valve disposed in the entire gas flow path between the flow rate controller and the junction; The plasma processing apparatus according to claim 3 .

5. The injection unit is configured to be able to select the type of the injection gas for each of the gas introduction parts.

5. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

6. The injection unit is configured to be able to adjust the flow rate of the injection gas for each of the gas introduction parts.

6. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

7. The control unit repeating the first step and the second step to subject the substrate to plasma processing; At least one of the type and flow rate of the injection gas supplied to each of the gas introduction parts is switched between the first step and the second step.

7. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

Images