Etching method and plasma processing apparatus

Abstract

To provide a technique for etching a second region of a substrate while selectively protecting a first region of the substrate relative to the second region.SOLUTION: An etching method according to the present disclosure includes a step (a) of providing a substrate. The substrate includes a first region and a second region. The second region contains silicon and oxygen and the first region is a mask over the second region. The etching method further includes a step (b) of forming a deposit on the first region with a first plasma generated from a first process gas including carbon monoxide gas. The etching method further includes a step (c) of etching the second region using the mask with the deposit formed thereon.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY Exemplary embodiments of the present disclosure relate to an etching method, a plasma processing apparatus, and a substrate processing system. [Background technology]

[0002] In the manufacture of electronic devices, etching of a substrate is performed. Selectivity is required for the etching. That is, it is required to selectively etch a second region of a substrate while protecting a first region of the substrate. The following Patent Documents 1 and 2 disclose techniques for selectively etching a second region formed of silicon oxide with respect to a first region formed of silicon nitride. The techniques disclosed in these documents deposit fluorocarbons on the first and second regions of a substrate. The fluorocarbon deposited on the first region is used to protect the first region, and the fluorocarbon deposited on the second region is used to etch the second region. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-173240 A [Patent Document 2] JP 2016-111177 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques for etching a first region of a substrate while selectively protecting the second region relative to the first region. [Means for solving the problem]

[0005] In one exemplary embodiment, an etching method is provided. The etching method includes the step (a) of providing a substrate. The substrate has a first region and a second region. The second region includes silicon and oxygen, and the first region is a mask on the second region. The etching method further includes the step (b) of forming a deposit on the mask by a first plasma generated from a first process gas including carbon monoxide gas and a noble gas or nitrogen gas. The etching method further includes the step (c) of etching the second region using the mask with the deposit formed thereon. Effect of the Invention

[0006] According to one exemplary embodiment, a first region of a substrate may be selectively protected relative to a second region while allowing etching of the second region. [Brief description of the drawings]

[0007] [Figure 1] 1 is a flow diagram of an etching method according to an exemplary embodiment. [Diagram 2] 2 is a partially enlarged cross-sectional view of an example of a substrate to which the etching method shown in FIG. 1 can be applied. [Diagram 3] 2 is a partially enlarged cross-sectional view of another example of a substrate to which the etching method shown in FIG. 1 can be applied. [Figure 4] Each of (a) to (f) of FIG. 4 is a partially enlarged cross-sectional view of an example of a substrate in a state in which the corresponding step of the etching method shown in FIG. 1 has been applied. [Diagram 5] 1 is a schematic diagram illustrating a plasma processing apparatus according to an exemplary embodiment; [Figure 6] FIG. 13 is a schematic diagram of a plasma processing apparatus according to another exemplary embodiment. [Figure 7] FIG. 1 illustrates a substrate processing system according to an exemplary embodiment. [Figure 8] FIGS. 8(a) and 8(b) are diagrams showing the results of the first experiment, and FIGS. 8(c) and 8(d) are diagrams showing the results of the first comparative experiment. [Figure 9]FIGS. 9(a) and 9(b) are diagrams showing the results of the second experiment, and FIGS. 9(c) and 9(d) are diagrams showing the results of the second comparative experiment. [Figure 10] 13 is a graph showing the relationship between ion energy and aperture width obtained in a third experiment. [Figure 11] FIG. 13 is a diagram illustrating dimensions measured in the fourth to sixth experiments. [Figure 12] Figure 12 (a) to (f) are transmission electron microscope (TEM) images of the sample substrate after the formation of the deposit DP in the seventh to twelfth experiments, respectively. [Figure 13] 2 is a flow chart of a step STc according to an exemplary embodiment that can be employed in the etching method shown in FIG. 1. [Figure 14] Each of (a) to (e) of FIG. 14 is a partially enlarged cross-sectional view of an example of a substrate in a state in which the corresponding step of the etching method shown in FIG. 1 has been applied. [Figure 15] 4 is a flow diagram of an etching method according to another exemplary embodiment. [Figure 16] FIG. 13 is a schematic diagram of a plasma processing apparatus according to another exemplary embodiment. [Figure 17] Each of (a) to (d) of FIG. 17 is a partially enlarged cross-sectional view of an example of a substrate in a state in which the corresponding step of the etching method shown in FIG. 15 has been applied. [Figure 18] 1 is a partial enlarged cross-sectional view of yet another example substrate to which etching methods according to various exemplary embodiments may be applied; [Figure 19] Each of (a) of FIG. 19 and (b) of FIG. 19 is an enlarged cross-sectional view of a portion of an example substrate after a corresponding step of an etching method according to an example embodiment has been applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Various exemplary embodiments are described below.

[0009] In one exemplary embodiment, an etching method is provided. The etching method includes the step (a) of providing a substrate. The substrate has a first region and a second region. The second region comprises silicon oxide and the first region is formed of a different material than the second region. The etching method further includes the step (b) of forming a deposit preferentially on the first region with a first plasma generated from a first process gas comprising carbon monoxide gas. The etching method further includes the step (c) of etching the second region.

[0010] In the above embodiment, the carbon species formed from the first process gas deposits preferentially on the first region. On the second region containing oxygen, the deposition of the carbon species formed from the first process gas is suppressed. Therefore, in the above embodiment, the second region is etched in a state in which the deposit is preferentially formed on the first region. Therefore, according to the above embodiment, it is possible to etch the second region while selectively protecting the first region of the substrate with respect to the second region.

[0011] In one exemplary embodiment, the second region may be formed of silicon nitride. Step (c) may include step (c1) of forming another deposit on the substrate comprising a fluorocarbon by generating a plasma from a second process gas comprising a fluorocarbon gas. Step (c) may further include step (c2) of etching the second region by supplying ions from a plasma generated from a noble gas to the substrate on which the another deposit was formed.

[0012] In one exemplary embodiment, steps (b) and (c) may be repeated alternately.

[0013] In one exemplary embodiment, the second region may be surrounded by the first region. The second region may be etched in a self-aligned manner in step (c).

[0014] In one exemplary embodiment, the first region may be a photoresist mask formed over the second region.

[0015] In one exemplary embodiment, steps (b) and (c) may be performed in the same chamber.

[0016] In one exemplary embodiment, step (b) may be performed in a first chamber and step (c) may be performed in a second chamber.

[0017] In one exemplary embodiment, the etching method may further comprise, between steps (b) and (c), transferring the substrate from the first chamber to the second chamber under a vacuum environment.

[0018] In another exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a plasma generating unit, and a controller. The substrate support is disposed within the chamber. The plasma generating unit is configured to generate a plasma within the chamber. The controller is configured to effect a step (a) of preferentially forming a deposit on a first region of the substrate with a first plasma generated from a first process gas that includes carbon and does not include fluorine. The controller is further configured to effect a step (b) of etching a second region of the substrate.

[0019] In one exemplary embodiment, the control unit may be configured to further provide a step (c) of alternating between steps (a) and (b).

[0020] In one exemplary embodiment, step (b) may be performed in a number of cycles, each of which includes a step (b1) of forming a second deposit on the substrate that includes a fluorocarbon by generating a plasma from a second process gas that includes a fluorocarbon gas, and each of which further includes a step (b2) of etching a second region by supplying ions from the plasma generated from a noble gas to the substrate on which the second deposit was formed.

[0021] In one exemplary embodiment, the first process gas may include carbon monoxide gas or carbonyl sulfide gas.

[0022] In one exemplary embodiment, the first process gas may include carbon monoxide gas and hydrogen gas.

[0023] In one exemplary embodiment, step (a) may be performed at least when the aspect ratio of the recess defined by the first region and the second region is 4 or less.

[0024] In one exemplary embodiment, the first process gas may include a first component and a second component. The first component includes carbon and does not include fluorine. The second component includes carbon and either fluorine or hydrogen. The flow rate of the first component may be greater than the flow rate of the second component.

[0025] In one exemplary embodiment, the plasma processing apparatus may further include an upper electrode disposed above the substrate support. The upper electrode may include a top plate in contact with the interior space of the chamber. The top plate may be made of a silicon-containing material.

[0026] In one exemplary embodiment, the control unit may be configured to further effect the step of applying a negative DC voltage to the upper electrode when step (a) is occurring.

[0027] In one exemplary embodiment, the controller may be configured to further provide, after step (a) and before step (b), forming a silicon-containing deposit on the substrate. In one exemplary embodiment, forming a silicon-containing deposit on the substrate may include applying a negative DC voltage to the upper electrode when a plasma is generated in the chamber.

[0028] In yet another exemplary embodiment, a substrate processing system for processing a substrate is provided. The substrate has a first region and a second region. The second region includes silicon and oxygen. The first region is free of oxygen and is formed of a material different from that of the second region. The substrate processing system includes a deposition apparatus, an etching apparatus, and a transfer module. The deposition apparatus is configured to preferentially form a deposit on the first region with a first plasma generated from a first process gas that includes carbon and does not include fluorine. The etching apparatus is configured to etch the second region. The transfer module is configured to transfer the substrate between the deposition apparatus and the etching apparatus in a vacuum environment.

[0029] In yet another exemplary embodiment, an etching method is provided. The etching method includes the step (a) of providing a substrate on a substrate support disposed in a chamber of a plasma processing apparatus. The substrate has a first region and a second region. The second region includes silicon and oxygen. The first region does not include oxygen and is formed of a material different from the material of the second region. The etching method further includes the step (b) of selectively forming a deposit on the first region by supplying the substrate with chemical species from a plasma generated from a process gas that includes carbon and does not include fluorine. The etching method further includes the step (c) of etching the second region.

[0030] In the above embodiment, the carbon species formed from the process gas is selectively deposited on the first region. On the second region containing oxygen, the deposition of the carbon species formed from the process gas is suppressed. Therefore, in the above embodiment, the second region is etched in a state where the deposit is selectively present on the first region. Therefore, according to the above embodiment, it is possible to etch the second region while selectively protecting the first region of the substrate with respect to the second region.

[0031] In one exemplary embodiment, the process gas may be hydrogen-free.

[0032] In one exemplary embodiment, the process gas may further include oxygen. The process gas may include carbon monoxide gas or carbonyl sulfide gas.

[0033] In one exemplary embodiment, the energy of the ions supplied to the substrate in step (b) may be greater than or equal to 0 eV and less than or equal to 70 eV.

[0034] In one exemplary embodiment, the first region may be formed from silicon nitride.

[0035] In one exemplary embodiment, the second region may be formed of silicon oxide and may be surrounded by the first region. The second region may be etched in a self-aligned manner in step (c).

[0036] In one exemplary embodiment, the first region may be disposed over a second region to form a mask, and the second region may include a silicon-containing film.

[0037] In one exemplary embodiment, the plasma processing apparatus may be a capacitively coupled plasma processing apparatus. Radio frequency power may be supplied to an upper electrode of the plasma processing apparatus to generate plasma in step (b).

[0038] In one exemplary embodiment, the frequency of the radio frequency power may be 60 MHz or greater.

[0039] In one exemplary embodiment, the plasma processing apparatus may be an inductively coupled plasma processing apparatus.

[0040] In one exemplary embodiment, steps (b) and (c) may be performed in a plasma processing apparatus without removing the substrate from the chamber.

[0041] In one exemplary embodiment, the plasma processing apparatus used in step (b) may be a separate apparatus from the etching apparatus used in step (c), and the substrate may be transferred from the plasma processing apparatus used in step (b) to the etching apparatus used in step (c) through only a vacuum environment.

[0042] In one exemplary embodiment, step (b) may be performed at least when the aspect ratio of the recess defined by the first region and the second region is 4 or less.

[0043] In one exemplary embodiment, steps (b) and (c) may be repeated alternately.

[0044] In yet another exemplary embodiment, an etching method is also provided. The etching method includes a step (a) of preparing a substrate on a substrate support provided in a chamber of a plasma processing apparatus. The substrate has a first region and a second region. The second region includes silicon and oxygen. The first region does not include oxygen and is formed of a material different from the material of the second region. The etching method further includes a step (b) of selectively forming a deposit on the first region by supplying the substrate with chemical species from a plasma generated from a process gas including a first gas including carbon and not including fluorine and a second gas including carbon and fluorine or hydrogen. The etching method further includes a step (c) of etching the second region. In the step (b), the flow rate of the first gas is greater than the flow rate of the second gas.

[0045] In yet another exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a gas supply, a plasma generation unit, and a controller. The substrate support is disposed within the chamber. The gas supply is configured to supply a gas into the chamber. The plasma generation unit is configured to generate a plasma from the gas in the chamber. The controller is configured to control the gas supply and the plasma generation unit. The substrate support supports a substrate having a first region and a second region. The second region includes silicon and oxygen, and the first region includes no oxygen and is formed of a material different from the material of the second region. The controller controls the gas supply and the plasma generation unit to generate a plasma from a process gas including carbon and not including fluorine in the chamber to selectively form a deposit on the first region. The controller controls the gas supply and the plasma generation unit to generate a plasma from an etching gas in the chamber to etch the second region.

[0046] In yet another exemplary embodiment, a substrate processing system is provided. The substrate processing system includes a plasma processing device, an etching device, and a transfer module. The plasma processing device is configured to supply chemical species from a plasma generated from a carbon-containing, fluorine-free processing gas to the substrate to selectively form a deposit on a first region of the substrate. The substrate has a first region and a second region, the second region including silicon and oxygen, and the first region being oxygen-free and formed of a material different from the material of the second region. The etching device is configured to etch the second region. The transfer module is configured to transfer the substrate between the plasma processing device and the etching device through only a vacuum environment.

[0047] Various exemplary embodiments will now be described in detail with reference to the drawings, in which the same or corresponding parts are designated by the same reference numerals.

[0048] Fig. 1 is a flow diagram of an etching method according to one example embodiment. The etching method shown in Fig. 1 (hereinafter referred to as "method MT") starts with step STa. In step STa, a substrate W is provided. In step STa, the substrate W is prepared on a substrate support of a plasma processing apparatus. The substrate support is provided in a chamber of the plasma processing apparatus.

[0049] The substrate W has a first region R1 and a second region R2. The first region R1 is formed of a different material than the second region R2. The material of the first region R1 may be free of oxygen. The material of the first region R1 may include silicon nitride. The material of the second region R2 includes silicon and oxygen. The material of the second region R2 may include silicon oxide. The material of the second region R2 may include a low-k material including silicon, carbon, oxygen, and hydrogen.

[0050] FIG. 2 is a partially enlarged cross-sectional view of an example of a substrate to which the etching method shown in FIG. 1 can be applied. The substrate W shown in FIG. 2 has a first region R1 and a second region R2. The substrate W may further have a base region UR. The first region R1 of the substrate W shown in FIG. 2 includes a region R11 and a region R12. The region R11 is made of silicon nitride and forms a recess. The region R11 is provided on the base region UR. The region R12 extends on both sides of the region R11. The region R12 is formed of silicon nitride or silicon carbide. The second region R2 of the substrate W shown in FIG. 2 is made of silicon oxide and is provided in the recess provided by the region R11. That is, the second region R2 is surrounded by the first region R1. When the method MT is applied to the substrate W shown in FIG. 2, the second region R2 is etched in a self-aligned manner.

[0051] FIG. 3 is a partially enlarged cross-sectional view of another example of a substrate to which the etching method shown in FIG. 1 can be applied. The substrate WB shown in FIG. 3 can be used as the substrate W to which the method MT is applied. The substrate WB has a first region R1 and a second region R2. The first region R1 constitutes a mask in the substrate WB. The first region R1 is provided on the second region R2. The substrate WB may further have a base region UR. The second region R2 is provided on the base region UR. In the substrate WB, the first region R1 can be formed from the same material as the material of the first region R1 of the substrate W shown in FIG. 2. In addition, in the substrate WB, the second region R2 can be formed from the same material as the material of the second region R2 of the substrate W shown in FIG. 2.

[0052] Below, the steps subsequent to step STa of method MT will be described taking as an example the case where this is applied to substrate W shown in Fig. 2. In the following description, Fig. 4(a) to Fig. 4(f) will be referred to in addition to Fig. 1. Each of Fig. 4(a) to Fig. 4(f) is a partially enlarged cross-sectional view of an example of a substrate in a state where the corresponding step of the etching method shown in Fig. 1 has been applied.

[0053] In the method MT, step STa is followed by step STb and step STc in order. Note that step STc may be performed after step STa, and then step STb and step STc may be performed in order. Step STc may be performed after step STd. Also, multiple cycles each including step STb, step STc, and step STd may be performed in order. That is, step STb and step STc may be repeated alternately. Some of the multiple cycles may not include step STd.

[0054] In step STb, a deposit DP is selectively or preferentially formed on the first region R1. For this purpose, in step STb, plasma is generated from a process gas, i.e., a first process gas, in a chamber of a plasma processing apparatus. The first process gas contains carbon and does not contain fluorine. The first process gas contains, as a gas that contains carbon and does not contain fluorine, for example, carbon monoxide gas (CO gas), carbonyl sulfide gas (COS gas), or a hydrocarbon gas. The hydrocarbon gas is, for example, C2 H 2 Gas, C. 2 H 4 Gas, CH 4 Gas or C 2 H 6 The first process gas does not have to contain hydrogen. The first process gas may contain hydrogen gas (H 2 The first process gas may further include a rare gas, such as argon gas or helium gas. The first process gas may further include nitrogen gas (N 2 The first process gas may further include an inert gas such as a carbon-containing gas (carbon species). In the first process gas, the flow rate of the gas containing carbon and not containing fluorine may be 30 sccm or more and 200 sccm or less. In the first process gas, the flow rate of the gas containing carbon and not containing fluorine may be 90 sccm or more and 130 sccm or less. In the first process gas, the flow rate of the rare gas may be 0 sccm or more and 1000 sccm or less. In the first process gas, the flow rate of the rare gas may be 350 sccm or less. The flow rate of each gas in the first process gas may be determined by the volume of the internal space 10s in the chamber 10, etc. In the step STb, chemical species (carbon species) from the plasma are supplied to the substrate. The supplied chemical species selectively or preferentially form a deposit DP on the first region R1 as shown in (a) of FIG. 4. The deposit DP includes carbon.

[0055] In step STb, the first process gas may include a first gas and a second gas. The first gas is a gas containing carbon and not containing fluorine, for example, CO gas or COS gas. That is, the first process gas may include a first component containing carbon and not containing fluorine. The first component is, for example, carbon monoxide (CO) or carbonyl sulfide. The second gas is a gas containing carbon and fluorine or hydrogen, for example, a hydrofluorocarbon gas, a fluorocarbon gas, or a hydrocarbon gas. That is, the first process gas may further include a second component containing carbon and fluorine or hydrogen. The second component is, for example, a hydrofluorocarbon, a fluorocarbon, or a hydrocarbon. The hydrofluorocarbon gas is, for example, CHF 3 Gas, CH 3 F gas, CH 2 F 2 Fluorocarbon gases include, for example, C 4 F 6 The second gas containing carbon and hydrogen is, for example, CH 4 The first gas or the first component is a gas. The flow rate of the first gas or the first component is greater than the flow rate of the second gas or the second component. The ratio of the flow rate of the second gas or the second component to the flow rate of the first gas or the first component may be 0.2 or less. In the step STb using this first processing gas, in addition to the selective or preferential formation of the deposit DP on the first region R1, a thin protective film is formed on the sidewall defining the recess. Thus, the sidewall is protected from the plasma.

[0056] The first process gas used in the step STb is a mixture of CO gas and hydrogen gas (H 2 The first process gas may be a mixed gas containing CO gas and H. By using such a first process gas, the deposit DP selectively or preferentially forms a protective film having high resistance to etching in the step STc on the first region R1. 2 H relative to total gas flow rate 2The ratio of the gas flow rates may be not less than 1 / 19 and not more than 2 / 17. When the first process gas having such a ratio is used, the verticality of the side surface of the deposit DP formed on the first region R1 is increased.

[0057] In the step STb, the energy of the ions supplied to the substrate W may be equal to or greater than 0 eV and equal to or less than 70 eV. In this case, the reduction in the opening of the recess due to the deposit DP is suppressed.

[0058] In one embodiment, the plasma processing apparatus used in the process STb may be a capacitively coupled plasma processing apparatus. When a capacitively coupled plasma processing apparatus is used, high frequency power for generating plasma may be supplied to the upper electrode. In this case, the plasma can be formed in a region far from the substrate W. The frequency of the high frequency power may be 60 MHz or more. In another embodiment, the plasma processing apparatus used in the process STb may be an inductively coupled plasma processing apparatus.

[0059] Since process STb can selectively or preferentially form a deposit DP on the first region R1, process STb can be performed at least when the aspect ratio of the recess defined by the first region R1 and the second region R2 in the substrate W is 4 or less.

[0060] In the subsequent step STc, the second region R2 is etched as shown in FIG. 4(b). In one embodiment, the second region R2 is etched using chemical species from a plasma generated from an etching gas. In this case, the plasma is generated from the etching gas in a chamber of an etching apparatus. The etching gas is selected according to the material of the second region R2. The etching gas includes, for example, a fluorocarbon gas. The etching gas may further include a rare gas such as argon gas and an oxygen-containing gas such as oxygen gas.

[0061] The etching apparatus used in the process STc may be the plasma processing apparatus used in the process STb. That is, the process STb and the process STc may be performed in the same chamber. In this case, the process STb and the process STc are performed without removing the substrate W from the chamber of the plasma processing apparatus. Alternatively, the plasma processing apparatus used in the process STb may be an apparatus different from the etching apparatus used in the process STc. That is, the process STb may be performed in a first chamber, and the process STc may be performed in a second chamber. In this case, between the process STb and the process STc, the substrate W is transported from the plasma processing apparatus used in the process STb to the etching apparatus used in the process STc through only a vacuum environment. That is, between the process STb and the process STc, the substrate W is transported from the first chamber to the second chamber under a vacuum environment.

[0062] In the next step STd, ashing is performed. In step STd, the deposit DP is removed as shown in FIG. 4(c). In one embodiment, the deposit DP is etched using chemical species from a plasma generated from an ashing gas. In this case, a plasma is generated from an ashing gas in a chamber of an ashing device. The ashing gas includes an oxygen-containing gas, such as oxygen gas. The ashing gas includes N 2 Gas and H 2 It is to be noted that the method MT does not necessarily include step STd.

[0063] The ashing device used in the process STd may be the etching device used in the process STc. That is, the process STc and the process STd may be performed in the same chamber. In this case, the process STc and the process STd are performed without taking out the substrate W from the chamber of the etching device. Alternatively, the etching device used in the process STc may be a device different from the ashing device used in the process STd. That is, the chamber used in the process STd may be a chamber different from the chamber used in the process STc. In this case, between the process STc and the process STd, the substrate W is transported from the etching device used in the process STc to the ashing device used in the process STd through only a vacuum environment. That is, between the process STc and the process STd, the substrate W is transported from the chamber for the process STc to the chamber for the process STd under a vacuum environment. The ashing device used in the process STd may be the plasma processing device used in the process STb.

[0064] In the case where multiple cycles are performed in sequence in the method MT, step STJ is then performed. In step STJ, it is determined whether or not a stop condition is satisfied. In step STJ, the stop condition is satisfied when the number of times the cycle is performed reaches a predetermined number. In the case where it is determined that the stop condition is not satisfied in step STJ, the cycle is performed again. That is, step STb is performed again, and a deposit DP is formed on the first region R1 as shown in FIG. 4(d). Then, step STc is performed, and the second region R2 is etched as shown in FIG. 4(e). In the method MT, the first region R1 may be removed at the bottom of the recess by step STc as shown in FIG. 4(e). Then, step STd is performed, and the deposit DP is removed as shown in FIG. 4(f). On the other hand, in the case where it is determined that the stop condition is satisfied in step STJ, the method MT is terminated.

[0065] In step STb of the method MT, the carbon species formed from the first process gas is selectively or preferentially deposited on the first region R1. On the second region R2 containing oxygen, the deposition of the carbon species formed from the first process gas is suppressed. Therefore, in the method MT, the second region R2 is etched in a state in which the deposit DP is preferentially formed on the first region R1. Therefore, according to the method MT, it is possible to etch the second region R2 while selectively protecting the first region R1 with respect to the second region R2. In addition, in the method MT, the deposit DP is selectively or preferentially formed on the first region R1, so that the closure of the opening of the recess defined by the first region R1 and the second region R2 is suppressed.

[0066] In addition, the carbon species generated from the CO gas in the step STb is an ionic species. 4 Gas or CH 3 From F gas, CH 2 or radicals such as CHF are easily generated. Such radicals are highly reactive and easily deposited isotropically on the surface of the substrate W. In contrast, chemical species having ionic properties are deposited anisotropically on the substrate W. That is, the chemical species having ionic properties are more likely to adhere to the upper surface of the first region R1 than to the wall surface defining the recess. Carbon monoxide is easily removed from the surface of the substrate W. Therefore, in order to adsorb carbon monoxide on the surface of the substrate W, it is necessary to remove oxygen from the surface of the substrate W by colliding ions with the surface. In addition, carbon monoxide has a simple structure and is difficult to crosslink. Therefore, in order to deposit carbon monoxide on the surface of the substrate W, it is necessary to form dangling bonds on the surface of the substrate W. Since the carbon chemical species generated from the CO gas in the process STb is a chemical species having ionic properties, oxygen can be removed from the upper surface of the first region R1, dangling bonds can be formed on the upper surface, and the carbon monoxide can be selectively deposited on the first region R1.

[0067] Reference will now be made to Fig. 5. Fig. 5 is a diagram that illustrates a schematic diagram of a plasma processing apparatus according to an exemplary embodiment. The plasma processing apparatus 1 illustrated in Fig. 5 can be used in the method MT. The plasma processing apparatus 1 may be used in all steps of the method MT, or may be used only in step STb.

[0068] The plasma processing apparatus 1 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein.

[0069] In one embodiment, the chamber 10 may include a chamber body 12. The chamber body 12 has a substantially cylindrical shape. An internal space 10s is provided inside the chamber body 12. The chamber body 12 is made of a conductor such as aluminum. The chamber body 12 is grounded. A corrosion-resistant film is provided on the inner wall surface of the chamber body 12. The corrosion-resistant film may be a film made of a ceramic such as aluminum oxide or yttrium oxide.

[0070] The sidewall of the chamber body 12 provides a passage 12p. The substrate W passes through the passage 12p when being transferred between the internal space 10s and the outside of the chamber 10. The passage 12p can be opened and closed by a gate valve 12g. The gate valve 12g is provided along the sidewall of the chamber body 12.

[0071] The plasma processing apparatus 1 further includes a substrate support 14. The substrate support 14 is configured to support the substrate W in the chamber 10, i.e., in the internal space 10s. The substrate support 14 is provided in the chamber 10. The substrate support 14 may be supported by a support portion 13. The support portion 13 is made of an insulating material. The support portion 13 has a substantially cylindrical shape. The support portion 13 extends upward from the bottom of the chamber body 12 in the internal space 10s.

[0072] In one embodiment, the substrate support 14 may include a lower electrode 18 and an electrostatic chuck 20. The substrate support 14 may further include an electrode plate 16. The electrode plate 16 is made of a conductor such as aluminum and has a generally disk-like shape. The lower electrode 18 is provided on the electrode plate 16. The lower electrode 18 is made of a conductor such as aluminum and has a generally disk-like shape. The lower electrode 18 is electrically connected to the electrode plate 16.

[0073] The electrostatic chuck 20 is provided on the lower electrode 18. The substrate W is placed on the upper surface of the electrostatic chuck 20. The electrostatic chuck 20 has a body formed from a dielectric material. The body of the electrostatic chuck 20 has a substantially disk shape. The electrostatic chuck 20 further has an electrode 20e. The electrode 20e is provided in the body of the electrostatic chuck 20. The electrode 20e is a film-like electrode. The electrode 20e is connected to a DC power supply 20p via a switch 20s. When a voltage from the DC power supply 20p is applied to the electrode of the electrostatic chuck 20, an electrostatic attractive force is generated between the electrostatic chuck 20 and the substrate W. Due to the generated electrostatic attractive force, the substrate W is attracted to the electrostatic chuck 20 and held by the electrostatic chuck 20.

[0074] The substrate support 14 may support an edge ring ER disposed thereon. The edge ring ER may be made of, but is not limited to, silicon, silicon carbide, or quartz. When processing of a substrate W is performed in the chamber 10, the substrate W is disposed on the electrostatic chuck 20 and within a region surrounded by the edge ring ER.

[0075] The lower electrode 18 provides a flow path 18f therein. The flow path 18f receives a heat exchange medium (e.g., a refrigerant) supplied from a chiller unit 22 via a pipe 22a. The chiller unit 22 is provided outside the chamber 10. The heat exchange medium supplied to the flow path 18f is returned to the chiller unit 22 via a pipe 22b. In the plasma processing apparatus 1, the temperature of the substrate W placed on the electrostatic chuck 20 is adjusted by heat exchange between the heat exchange medium and the lower electrode 18.

[0076] The temperature of the substrate W may be regulated by one or more heaters provided in the substrate support 14. In the example shown in Figure 5, multiple heaters HT are provided in the electrostatic chuck 20. Each of the multiple heaters HT may be a resistive heating element. The multiple heaters HT are connected to a heater controller HC. The heater controller HC is configured to provide a regulated amount of power to each of the multiple heaters HT.

[0077] The plasma processing apparatus 1 may further include a gas supply line 24. The gas supply line 24 supplies a heat transfer gas (e.g., He gas) to a gap between the upper surface of the electrostatic chuck 20 and the rear surface of the substrate W. The heat transfer gas is supplied to the gas supply line 24 from a heat transfer gas supply mechanism.

[0078] The plasma processing apparatus 1 further includes an upper electrode 30. The upper electrode 30 is provided above the substrate support 14. The upper electrode 30 is supported on the upper part of the chamber body 12 via a member 32. The member 32 is made of an insulating material. The upper electrode 30 and the member 32 close the upper opening of the chamber body 12.

[0079] The upper electrode 30 may include a top plate 34 and a support 36. The lower surface of the top plate 34 is the lower surface on the side of the internal space 10s and defines the internal space 10s. That is, the top plate 34 is in contact with the internal space 10s. The top plate 34 may be formed from a silicon-containing material. The top plate 34 is formed from, for example, silicon or silicon carbide. The top plate 34 provides a plurality of gas holes 34a. The plurality of gas holes 34a penetrate the top plate 34 in the plate thickness direction.

[0080] The support 36 detachably supports the top plate 34. The support 36 is made of a conductive material such as aluminum. The support 36 provides a gas diffusion chamber 36a therein. The support 36 further provides a plurality of gas holes 36b. The plurality of gas holes 36b extend downward from the gas diffusion chamber 36a. The plurality of gas holes 36b communicate with the plurality of gas holes 34a, respectively. The support 36 further provides a gas inlet 36c. The gas inlet 36c is connected to the gas diffusion chamber 36a. A gas supply pipe 38 is connected to the gas inlet 36c.

[0081] A gas source group 40 is connected to the gas supply pipe 38 via a valve group 41, a flow rate controller group 42, and a valve group 43. The gas source group 40, the valve group 41, the flow rate controller group 42, and the valve group 43 configure a gas supply unit GS.

[0082] The gas source group 40 includes a plurality of gas sources. When the plasma processing apparatus 1 is used in the process STb, the plurality of gas sources includes one or more gas sources for a first process gas used in the process STb. When the plasma processing apparatus 1 is used in the process STc, the plurality of gas sources includes one or more gas sources for an etching gas used in the process STc. When the plasma processing apparatus 1 is used in the process STd, the plurality of gas sources includes one or more gas sources for an ashing gas used in the process STd.

[0083] Each of the valve group 41 and the valve group 43 includes a plurality of on-off valves. The flow rate controller group 42 includes a plurality of flow rate controllers. Each of the plurality of flow rate controllers in the flow rate controller group 42 is a mass flow controller or a pressure-controlled flow rate controller. Each of the plurality of gas sources in the gas source group 40 is connected to the gas supply pipe 38 via a corresponding on-off valve in the valve group 41, a corresponding flow rate controller in the flow rate controller group 42, and a corresponding on-off valve in the valve group 43.

[0084] The plasma processing apparatus 1 may further include a shield 46. The shield 46 is detachably provided along the inner wall surface of the chamber body 12. The shield 46 is also provided on the outer periphery of the support portion 13. The shield 46 prevents by-products of the plasma processing from adhering to the chamber body 12. The shield 46 is formed, for example, by forming a corrosion-resistant film on the surface of a member made of aluminum. The corrosion-resistant film may be a film made of a ceramic such as yttrium oxide.

[0085] The plasma processing apparatus 1 may further include a baffle member 48. The baffle member 48 is provided between the support 13 and the side wall of the chamber body 12. The baffle member 48 is formed by forming a corrosion-resistant film on the surface of a plate-like member made of aluminum, for example. The corrosion-resistant film may be a film made of ceramic, such as yttrium oxide. The baffle member 48 provides a plurality of through holes. An exhaust port 12e is provided below the baffle member 48 and at the bottom of the chamber body 12. An exhaust device 50 is connected to the exhaust port 12e via an exhaust pipe 52. The exhaust device 50 has a pressure adjustment valve and a vacuum pump, such as a turbo molecular pump.

[0086] The plasma processing apparatus 1 further includes a high-frequency power supply 62 and a bias power supply 64. The high-frequency power supply 62 is configured to generate high-frequency power (hereinafter, referred to as "high-frequency power HF"). The high-frequency power HF has a frequency suitable for generating plasma. The frequency of the high-frequency power HF is, for example, 27 MHz or more and 100 MHz or less. The frequency of the high-frequency power HF may be 60 MHz or more. The high-frequency power supply 62 is connected to the high-frequency electrode via a matching device 66. In one embodiment, the high-frequency electrode is the upper electrode 30. The matching device 66 has a circuit for matching the impedance of the load side (upper electrode 30 side) of the high-frequency power supply 62 to the output impedance of the high-frequency power supply 62. In one embodiment, the high-frequency power supply 62 may constitute a plasma generating unit. Note that the high-frequency power supply 62 may be connected to an electrode (for example, the lower electrode 18) in the substrate support 14 via the matching device 66. That is, the high-frequency electrode may be an electrode (for example, the lower electrode 18) in the substrate support 14.

[0087] The bias power supply 64 is configured to provide an electric bias EB to a bias electrode (e.g., the lower electrode 18) in the substrate support 14. The electric bias EB has a bias frequency suitable for attracting ions to the substrate W. The bias frequency of the electric bias EB is, for example, not less than 100 kHz and not more than 40.68 MHz. When the electric bias EB is used together with the radio frequency power HF, the electric bias EB has a frequency lower than the frequency of the radio frequency power HF.

[0088] In one embodiment, the electric bias EB may be a high frequency bias power (hereinafter referred to as "high frequency power LF"). The waveform of the high frequency power LF is a sine wave shape having a bias frequency. In this embodiment, the bias power supply 64 is connected to the bias electrode (e.g., the lower electrode 18) via a matching box 68 and the electrode plate 16. The matching box 68 has a circuit for matching the impedance of the load side (lower electrode 18 side) of the bias power supply 64 to the output impedance of the bias power supply 64. In another embodiment, the electric bias EB may be a voltage pulse. The voltage pulse may be a negative voltage pulse. The negative voltage pulse may be a negative DC voltage pulse. In this embodiment, the voltage pulse is applied to the lower electrode 18 periodically at a time interval (i.e., a period) having a time length of the inverse of the bias frequency.

[0089] The plasma processing apparatus 1 further includes a control unit MC. The control unit MC may be a computer including a processor, a storage unit such as a memory, an input device, a display device, a signal input / output interface, and the like. The control unit MC controls each unit of the plasma processing apparatus 1. In the control unit MC, an operator can use the input device to input commands and the like to manage the plasma processing apparatus 1. In addition, the control unit MC can visualize and display the operating status of the plasma processing apparatus 1 using the display device. Furthermore, a control program and recipe data are stored in the storage unit of the control unit MC. The control program is executed by the processor of the control unit MC to execute various processes in the plasma processing apparatus 1. The processor of the control unit MC executes the control program and controls each unit of the plasma processing apparatus 1 according to the recipe data, whereby at least some or all of the steps of the method MT are executed in the plasma processing apparatus 1.

[0090] The control unit MC may bring about a process STb. When the process STb is performed in the plasma processing apparatus 1, the control unit MC controls the gas supply unit GS to supply a first process gas into the chamber 10. The control unit MC also controls the exhaust unit 50 to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the first process gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 to supply high frequency power HF. The control unit MC may also control the bias power supply 64 to supply an electric bias EB.

[0091] The control unit MC may further provide a process STc. When the process STc is performed in the plasma processing apparatus 1, the control unit MC controls the gas supply unit GS to supply an etching gas into the chamber 10. The control unit MC also controls the exhaust unit 50 to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit MC also controls the plasma generation unit to generate plasma from the etching gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 to supply high frequency power HF. The control unit MC may also control the bias power supply 64 to supply an electric bias EB.

[0092] The control unit MC may further perform a step STd. When the step STd is performed in the plasma processing apparatus 1, the control unit MC controls the gas supply unit GS to supply an ashing gas into the chamber 10. The control unit MC also controls the exhaust unit 50 to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the ashing gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 to supply high frequency power HF. The control unit MC may also control the bias power supply 64 to supply an electric bias EB.

[0093] The control unit MC may further cause the above-mentioned multiple cycles to be executed in sequence. The control unit MC may further cause the step STb and the step STc to be repeated alternately.

[0094] Reference is now made to Fig. 6. Fig. 6 is a diagram illustrating a schematic diagram of a plasma processing apparatus according to another exemplary embodiment. The plasma processing apparatus used in the method MT may be an inductively coupled plasma processing apparatus, such as the plasma processing apparatus 1B illustrated in Fig. 6. The plasma processing apparatus 1B may be used in all steps of the method MT, or may be used only in step STb.

[0095] The plasma processing apparatus 1B includes a chamber 110. The chamber 110 provides an internal space 110s therein. In one embodiment, the chamber 110 may include a chamber body 112. The chamber body 112 has a substantially cylindrical shape. The internal space 110s is provided inside the chamber body 112. The chamber body 112 is made of a conductor such as aluminum. The chamber body 112 is grounded. A corrosion-resistant film is provided on the inner wall surface of the chamber body 112. The corrosion-resistant film may be a film made of a ceramic such as aluminum oxide or yttrium oxide.

[0096] The sidewall of the chamber body 112 provides a passage 112p. The substrate W passes through the passage 112p when being transferred between the internal space 110s and the outside of the chamber 110. The passage 112p can be opened and closed by a gate valve 112g. The gate valve 112g is provided along the sidewall of the chamber body 112.

[0097] The plasma processing apparatus 1B further includes a substrate support 114. The substrate support 114 is configured to support the substrate W in the chamber 110, i.e., in the internal space 110s. The substrate support 114 is provided in the chamber 110. The substrate support 114 may be supported by a support portion 113. The support portion 113 is made of an insulating material. The support portion 113 has a substantially cylindrical shape. The support portion 113 extends upward from a bottom portion of the chamber body 112 in the internal space 110s.

[0098] In one embodiment, the substrate support 114 may include a lower electrode 118 and an electrostatic chuck 120. The substrate support 114 may further include an electrode plate 116. The electrode plate 116 is made of a conductor such as aluminum and has a generally disk-like shape. The lower electrode 118 is provided on the electrode plate 116. The lower electrode 118 is made of a conductor such as aluminum and has a generally disk-like shape. The lower electrode 118 is electrically connected to the electrode plate 116.

[0099] The plasma processing apparatus 1B further includes a bias power supply 164. The bias power supply 164 is connected to a bias electrode (e.g., the lower electrode 18) in the substrate support 114 via a matching box 166. The bias power supply 164 and the matching box 166 are configured similarly to the bias power supply 64 and the matching box 66 of the plasma processing apparatus 1, respectively.

[0100] The electrostatic chuck 120 is provided on the lower electrode 118. The electrostatic chuck 120 has a body and an electrode, and is configured similarly to the electrostatic chuck 20 of the plasma processing apparatus 1. The electrode of the electrostatic chuck 120 is connected to a DC power supply 120p via a switch 120s. When a voltage from the DC power supply 120p is applied to the electrode of the electrostatic chuck 120, an electrostatic attractive force is generated between the electrostatic chuck 120 and the substrate W. Due to the generated electrostatic attractive force, the substrate W is attracted to the electrostatic chuck 120 and held by the electrostatic chuck 120.

[0101] The lower electrode 118 provides a flow path 118f therein. The flow path 118f receives a heat exchange medium supplied from a chiller unit through a pipe 122a, similar to the flow path 18f of the plasma processing apparatus 1. The heat exchange medium supplied to the flow path 118f is returned to the chiller unit through a pipe 122b.

[0102] The substrate support 114 may support an edge ring ER disposed thereon, similar to the substrate support 14 of the plasma processing apparatus 1. The substrate support 114 may also have one or more heaters HT disposed therein, similar to the substrate support 14 of the plasma processing apparatus 1. The one or more heaters HT are connected to a heater controller HC. The heater controller HC is configured to supply a regulated amount of power to the one or more heaters HT.

[0103] The plasma processing apparatus 1B may further include a gas supply line 124. Similar to the gas supply line 24 of the plasma processing apparatus 1, the gas supply line 124 supplies a heat transfer gas (e.g., He gas) to the gap between the upper surface of the electrostatic chuck 120 and the back surface of the substrate W.

[0104] The plasma processing apparatus 1B may further include a shield 146. The shield 146 has a configuration similar to that of the shield 46 of the plasma processing apparatus 1. The shield 146 is detachably provided along the inner wall surface of the chamber body 112. The shield 146 is also provided on the outer periphery of the support portion 113.

[0105] The plasma processing apparatus 1B may further include a baffle member 148. The baffle member 148 has a configuration similar to that of the baffle member 48 of the plasma processing apparatus 1. The baffle member 148 is provided between the support portion 113 and a sidewall of the chamber body 112. An exhaust port 112e is provided below the baffle member 148 and at the bottom of the chamber body 112. An exhaust device 150 is connected to the exhaust port 112e via an exhaust pipe 152. The exhaust device 150 has a pressure regulating valve and a vacuum pump such as a turbo molecular pump.

[0106] The ceiling of the chamber body 112 provides an opening. The opening in the ceiling of the chamber body 112 is closed by a window member 130. The window member 130 is made of a dielectric material such as quartz. The window member 130 has, for example, a plate shape. As an example, the distance between the lower surface of the window member 130 and the upper surface of the substrate W placed on the electrostatic chuck 120 is set to 120 mm to 180 mm.

[0107] A side wall of the chamber 110 or the chamber body 112 provides a gas inlet 112i. A gas supply unit GSB is connected to the gas inlet 112i via a gas supply pipe 138. The gas supply unit GSB includes a gas source group 140, a flow rate controller group 142, and a valve group 143. The gas source group 140 is configured similarly to the gas source group 40 of the plasma processing apparatus 1 and includes a plurality of gas sources. The flow rate controller group 142 is configured similarly to the flow rate controller group 42 of the plasma processing apparatus 1. The valve group 143 is configured similarly to the valve group 43 of the plasma processing apparatus 1. Each of the plurality of gas sources of the gas source group 140 is connected to the gas supply pipe 138 via a corresponding flow rate controller of the flow rate controller group 142 and a corresponding opening and closing valve of the valve group 143. The gas inlet 112i may be formed in another location, such as the window member 130, instead of the side wall of the chamber body 112.

[0108] The plasma processing apparatus 1B further includes an antenna 151 and a shield member 160. The antenna 151 and the shield member 160 are provided on the ceiling of the chamber 110 and on the window member 130. The antenna 151 and the shield member 160 are provided outside the chamber 110. In one embodiment, the antenna 151 has an inner antenna element 153a and an outer antenna element 153b. The inner antenna element 153a is a spiral coil and extends above the center of the window member 130. The outer antenna element 153b is a spiral coil and extends above the window member 130 and outside the inner antenna element 153a. Each of the inner antenna element 153a and the outer antenna element 153b is formed of a conductor such as copper, aluminum, or stainless steel.

[0109] The plasma processing apparatus 1B may further include a plurality of clamping bodies 154. Both the inner antenna element 153a and the outer antenna element 153b are clamped by and supported by the plurality of clamping bodies 154. Each of the plurality of clamping bodies 154 has a rod-like shape. The plurality of clamping bodies 154 extend radially from near the center of the inner antenna element 153a to the outside of the outer antenna element 153b.

[0110] The shield member 160 covers the antenna 151. The shield member 160 includes an inner shield wall 162a and an outer shield wall 162b. The inner shield wall 162a has a cylindrical shape. The inner shield wall 162a is provided between the inner antenna element 153a and the outer antenna element 153b so as to surround the inner antenna element 153a. The outer shield wall 162b has a cylindrical shape. The outer shield wall 162b is provided outside the outer antenna element 153b so as to surround the outer antenna element 153b.

[0111] The shield member 160 further includes an inner shield plate 163a and an outer shield plate 163b. The inner shield plate 163a has a disk shape and is provided above the inner antenna element 153a so as to cover the opening of the inner shield wall 162a. The outer shield plate 163b has a ring shape and is provided above the outer antenna element 153b so as to cover the opening between the inner shield wall 162a and the outer shield wall 162b.

[0112] The shapes of the shielding walls and shielding plates of the shielding member 160 are not limited to the shapes described above. The shape of the shielding walls of the shielding member 160 may be another shape, such as a rectangular cylindrical shape.

[0113] The plasma processing apparatus 1B further includes a high-frequency power supply 170a and a high-frequency power supply 170b. The high-frequency power supply 170a and the high-frequency power supply 170b constitute a plasma generating unit. The high-frequency power supply 170a and the high-frequency power supply 170b are connected to the inner antenna element 153a and the outer antenna element 153b, respectively. The high-frequency power supply 170a and the high-frequency power supply 170b supply high-frequency power having the same frequency or different frequencies to the inner antenna element 153a and the outer antenna element 153b, respectively. When the high-frequency power from the high-frequency power supply 170a is supplied to the inner antenna element 153a, an induction magnetic field is generated in the internal space 110s, and the gas in the internal space 110s is excited by the induction magnetic field. As a result, plasma is generated above the central region of the substrate W. When the high-frequency power from the high-frequency power supply 170b is supplied to the outer antenna element 153b, an induction magnetic field is generated in the internal space 110s, and the gas in the internal space 110s is excited by the induction magnetic field. This causes an annular plasma to be generated above the peripheral region of the substrate W.

[0114] The electrical lengths of the inner antenna element 153a and the outer antenna element 153b may be adjusted according to the high frequency powers output from the high frequency power sources 170a and 170b, respectively. For this purpose, the height positions of the inner shield plate 163a and the outer shield plate 163b may be individually adjusted by the actuators 168a and 168b.

[0115] The plasma processing apparatus 1B further includes a control unit MC. The control unit MC of the plasma processing apparatus 1B is configured similarly to the control unit MC of the plasma processing apparatus 1. The control unit MC controls each unit of the plasma processing apparatus 1B, so that at least some or all of the steps of the method MT are performed in the plasma processing apparatus 1B.

[0116] The control unit MC may bring about a process STb. When the process STb is performed in the plasma processing apparatus 1B, the control unit MC controls the gas supply unit GSB to supply a first process gas into the chamber 110. The control unit MC also controls the exhaust unit 150 to set the pressure of the gas in the chamber 110 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the first process gas in the chamber 110. Specifically, the control unit MC controls the high frequency power supplies 170a and 170b to supply high frequency power. The control unit MC may also control the bias power supply 164 to supply an electric bias EB.

[0117] The control unit MC may further provide a process STc. When the process STc is performed in the plasma processing apparatus 1B, the control unit MC controls the gas supply unit GSB to supply an etching gas into the chamber 110. The control unit MC also controls the exhaust unit 150 to set the pressure of the gas in the chamber 110 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the etching gas in the chamber 110. Specifically, the control unit MC controls the high frequency power sources 170a and 170b to supply high frequency power. The control unit MC may also control the bias power source 164 to supply an electric bias EB.

[0118] The control unit MC may further perform a step STd. When the step STd is performed in the plasma processing apparatus 1B, the control unit MC controls the gas supply unit GSB to supply an ashing gas into the chamber 110. The control unit MC also controls the exhaust unit 150 to set the pressure of the gas in the chamber 110 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the ashing gas in the chamber 110. Specifically, the control unit MC controls the high frequency power supplies 170a and 170b to supply high frequency power. The control unit may also control the bias power supply 164 to supply an electric bias EB.

[0119] In the plasma processing apparatus 1B, the control unit MC may further cause the above-mentioned multiple cycles to be executed in sequence, and may further cause the control unit MC to alternately repeat the process STb and the process STc.

[0120] Reference will now be made to FIG. 7. FIG. 7 is a diagram showing a substrate processing system according to an exemplary embodiment. The substrate processing system PS shown in FIG. 7 can be used in a method MT. The substrate processing system PS includes stages 2a-2d, containers 4a-4d, a loader module LM, an aligner AN, load lock modules LL1, LL2, process modules PM1-PM6, a transfer module TM, and a controller MC. The number of stages, containers, and load lock modules in the substrate processing system PS can be any number equal to or greater than one. The number of process modules in the substrate processing system PS can be any number equal to or greater than one.

[0121] The stages 2a to 2d are arranged along one edge of the loader module LM. The containers 4a to 4d are mounted on the stages 2a to 2d, respectively. Each of the containers 4a to 4d is, for example, a container called a FOUP (Front Opening Unified Pod). Each of the containers 4a to 4d is configured to accommodate a substrate W therein.

[0122] The loader module LM has a chamber. The pressure in the chamber of the loader module LM is set to atmospheric pressure. The loader module LM has a transport device TU1. The transport device TU1 is, for example, a transport robot, and is controlled by the controller MC. The transport device TU1 is configured to transport the substrate W through the chamber of the loader module LM. The transport device TU1 can transport the substrate W between each of the containers 4a to 4d and the aligner AN, between the aligner AN and each of the load lock modules LL1, LL2, and between each of the load lock modules LL1, LL2 and each of the containers 4a to 4d. The aligner AN is connected to the loader module LM. The aligner AN is configured to adjust the position of the substrate W (calibrate the position).

[0123] Each of the load lock modules LL1 and LL2 is provided between the loader module LM and the transfer module TM. Each of the load lock modules LL1 and LL2 provides a preliminary reduced pressure chamber.

[0124] The transfer module TM is connected to each of the load lock modules LL1 and LL2 via gate valves. The transfer module TM has a transfer chamber TC whose internal space can be depressurized. The transfer module TM has a transfer apparatus TU2. The transfer apparatus TU2 is, for example, a transfer robot, and is controlled by a controller MC. The transfer apparatus TU2 is configured to transfer a substrate W via the transfer chamber TC. The transfer apparatus TU2 can transfer the substrate W between each of the load lock modules LL1, LL2 and each of the process modules PM1 to PM6, and between any two of the process modules PM1 to PM6.

[0125] Each of the process modules PM1 to PM6 is an apparatus configured to perform a dedicated substrate processing. One of the process modules PM1 to PM6 is a plasma processing apparatus used in a process STb, such as the plasma processing apparatus 1 or the plasma processing apparatus 1B. The process module of the substrate processing system PS used in the process STb may be used in the process STd.

[0126] Another one of the process modules PM1 to PM6 is an etching apparatus used in the process STc. The process module used in the process STc may have a similar configuration to the plasma processing apparatus 1 or the plasma processing apparatus 1B. The process module of the substrate processing system PS used in the process STc may be used in the process STd.

[0127] Another one of the process modules PM1 to PM6 may be an ashing device used in step STd. The process module used in step STd may have the same configuration as the plasma processing apparatus 1 or the plasma processing apparatus 1B.

[0128] The controller MC is configured to control each part of the substrate processing system PS. The controller MC may be a computer including a processor, a storage device, an input device, a display device, etc. The controller MC executes a control program stored in the storage device and controls each part of the substrate processing system PS based on recipe data stored in the storage device. The method MT is executed in the substrate processing system PS by the control of each part of the substrate processing system PS by the controller MC.

[0129] When the method MT is performed using a substrate processing system PS, the controller MC controls a process module for step STb, i.e., a plasma processing apparatus or deposition apparatus, to supply chemical species from the plasma to the substrate W to selectively or preferentially form a deposit DP on the first region R1.

[0130] When the process STb and the process STc are performed in different process modules, the controller MC controls the transfer module TM to transfer the substrate W from the process module for the process STb to the process module for the process STc via the transfer chamber TC. Therefore, the substrate W is transferred from the chamber (first chamber) of the process module for the process STb to the chamber (second chamber) of the process module for the process STc via only the vacuum environment. That is, between the process STb and the process STc, the substrate W is transferred from the first chamber to the second chamber under the vacuum environment. Note that when the process STb and the process STc are performed in the same process module, the substrate W is continuously placed in the chamber of that process module.

[0131] Next, the control unit MC controls the process module used in the step STc, that is, the etching device, so as to etch the second region R2.

[0132] When the process STc and the process STd are performed in different process modules, the controller MC controls the transfer module TM to transfer the substrate W from the chamber of the process module for the process STc to the chamber of the process module for the process STd via the transfer chamber TC. Therefore, the substrate W is transferred from the chamber of the process module for the process STc to the chamber of the process module for the process STd via only the vacuum environment. That is, between the process STc and the process STd, the substrate W is transferred from the chamber for the process STc to the chamber for the process STd under the vacuum environment. Note that when the process STc and the process STd are performed in the same process module, the substrate W is continuously placed in that process module.

[0133] Next, the control unit MC controls the process module used in step STd, that is, the ashing device, so as to remove the deposit DP.

[0134] Various experiments performed to evaluate Method MT will be described below, but the experiments described below are not intended to limit the present disclosure.

[0135] (First experiment and first comparative experiment)

[0136] In the first experiment and the first comparative experiment, a sample substrate SW was prepared. The sample substrate SW had a first region R1 and a second region R2, and a recess RC was defined by the first region R1 and the second region R2 (see FIG. 8(b) and FIG. 8(d)). The first region R1 was made of silicon nitride, and the second region R2 was made of silicon oxide. In the sample substrate SW of the first experiment, the recess RC had a width of 12 nm and a depth of 13 nm. In the sample substrate SW of the first comparative experiment, the recess RC had a width of 12 nm and a depth of 25 nm. In the first experiment, a mixed gas of CO gas and Ar gas was used as a first processing gas in the plasma processing apparatus 1, and a deposit DP was formed on the sample substrate SW. In the first comparative experiment, a mixture gas of CO gas and Ar gas was used as a first processing gas in the plasma processing apparatus 1. 3 A mixture of F gas and Ar gas was used to form a deposit DP on the sample substrate SW. The conditions for forming the deposit DP in the first experiment and the first comparative experiment are shown below. <Conditions for the formation of deposit DP in the first experiment and the first comparative experiment> High frequency power HF: 800W Radio frequency power in the first experiment LF: 0W High frequency power in the first comparative experiment LF: 0W Processing time: 1st experiment 120 seconds, 1st comparison experiment 30 seconds

[0137] The results of the first experiment are shown in (a) and (b) of FIG. 8. (a) of FIG. 8 shows a transmission electron microscope (TEM) image of the sample substrate SW on which the deposit DP was formed in the first experiment. (b) of FIG. 8 illustrates the sample substrate SW in the TEM image of (a) of FIG. 8. (c) and (d) of FIG. 8 show the results of the first comparative experiment. (c) of FIG. 8 shows a transmission electron microscope (TEM) image of the sample substrate SW on which the deposit DP was formed in the first comparative experiment. (d) of FIG. 8 illustrates the sample substrate SW in the TEM image of (c) of FIG. As shown in (c) and (d) of FIG. 8, CH 3In the first comparative experiment using F gas, the deposit DP was formed on both the first region R1 and the second region R2, and the width of the opening of the recess RC was narrowed. On the other hand, as shown in Figures 8(a) and 8(b), in the first experiment using CO gas, the deposit DP was selectively or preferentially formed on the first region R1, and the reduction in the width of the opening of the recess RC was suppressed.

[0138] (Second experiment and second comparative experiment)

[0139] In the second experiment and the second comparative experiment, a sample substrate SW was prepared. The prepared sample substrate SW had a first region R1 and a second region R2, and the first region R1 and the second region R2 defined a recess RC. The first region R1 was formed of silicon nitride, and the second region R2 was formed of silicon oxide. The prepared sample substrate had an aspect ratio smaller than the aspect ratio of the recess RC of the sample substrate used in the first experiment and the first comparative experiment. Specifically, in the sample substrate SW of the second experiment, the recess RC had a width of 12 nm and a depth of 7 nm, and the aspect ratio was about 0.6. In the sample substrate of the second comparative experiment, the recess RC had a width of 12 nm and a depth of 9 nm, and the aspect ratio was 0.8. In the second experiment, a deposit DP was formed on the sample substrate SW under the same conditions as those of the first experiment. In the second comparative experiment, a deposit DP was formed on the sample substrate SW under the same conditions as those in the first comparative experiment.

[0140] The results of the second experiment are shown in (a) and (b) of FIG. 9. (a) of FIG. 9 shows a transmission electron microscope (TEM) image of the sample substrate SW on which the deposit DP was formed in the second experiment. (b) of FIG. 9 illustrates the sample substrate SW in the TEM image of (a) of FIG. 9. (c) and (d) of FIG. 9 show the results of the second comparative experiment. (c) of FIG. 9 shows a transmission electron microscope (TEM) image of the sample substrate SW on which the deposit DP was formed in the second comparative experiment. (d) of FIG. 9 illustrates the sample substrate SW in the TEM image of (c) of FIG. 9. As shown in (c) and (d) of FIG. 9, CH 3 In the second comparative experiment using F gas, the deposit DP was formed on both the first region R1 and the second region R2, and the width of the opening of the recess RC was narrowed. On the other hand, as shown in Figures 9(a) and 9(b), in the second experiment using CO gas, the deposit DP was selectively formed on the first region R1, and the reduction in the width of the opening of the recess RC was suppressed. The results of the second experiment confirmed that by using CO gas, the deposit DP was selectively formed on the first region R1 even when the aspect ratio of the recess RC was small.

[0141] (Third experiment)

[0142] In the third experiment, a plurality of sample substrates SW having the same structure as the structure of the sample substrate in the first experiment were prepared. In the third experiment, a mixture gas of CO gas and Ar gas was used as the first processing gas in the plasma processing apparatus 1, and deposits DP were formed on the plurality of sample substrates SW. In the third experiment, the energy of the ions (i.e., ion energy) supplied to the plurality of sample substrates SW during the formation of the deposits DP were different from each other. In the third experiment, the ion energy was adjusted by changing the power level of the high frequency power LF. The other conditions of the third experiment were the same as the corresponding conditions of the first experiment. In the third experiment, the width of the opening of the recess RC of the plurality of sample substrates SW after the formation of the deposits DP was obtained. Then, the relationship between the ion energy and the width of the opening was obtained. The results are shown in the graph of FIG. 10. In the graph of FIG. 10, the horizontal axis indicates the ion energy, and the vertical axis indicates the width of the opening. As shown in FIG. 10, if the ion energy for the substrate W during the formation of the deposits DP was 70 eV or less, the reduction in the width of the opening of the recess RC was significantly suppressed.

[0143] (Experiments 4 to 6)

[0144] In each of the fourth to sixth experiments, a sample substrate having the same structure as the sample substrate in the first experiment was prepared. Then, a deposit DP was formed on the surface of the sample substrate using a plasma processing apparatus 1, and then etching of the second region R2 was performed. In the fourth experiment, a mixed gas of CO gas and Ar gas was used as the first processing gas for forming the deposit DP. In the fifth experiment, a mixed gas of CO gas and CH 4 In the sixth experiment, a mixture of CO gas and H was used as the first treatment gas to form the deposit DP. 2 A mixture of gases was used. Other conditions for forming the deposit DP in each of the fourth to sixth experiments were the same as those for forming the deposit DP in the first experiment. The etching conditions for the second region R2 in each of the fourth to sixth experiments are shown below. <Etching conditions for the second region R2> High frequency power HF:100W High frequency power LF: 100W Etching gas: NF 3 Gas and Ar gas mixture Processing time: 6 seconds

[0145] 11 is a diagram illustrating the dimensions measured in the fourth to sixth experiments. In each of the fourth to sixth experiments, the thickness T B , the depth D of the recess formed by etching the second region R2 s and the thickness T of the deposit DP due to etching of the second region R2. T The amount of decrease in the film thickness T B is the thickness of the deposit DP at the bottom of the recess. T is the thickness of the deposit DP on the first region R1.

[0146] The film thickness T measured in the fourth to sixth experiments B were 1.8 nm, 3.0 nm, and 1.6 nm, respectively. Therefore, when the first process gas was a mixture of CO gas and Ar gas or a mixture of CO gas and H 2 In the case of a mixture of gases, the first process gas is CH 4 The thickness of the deposit DP at the bottom of the recess was smaller than that when gas was included. s The increases in the thickness of the first process gas were 1.0 nm, 0.5 nm, and 0.9 nm, respectively. 2 In the case of a mixture of gases, the first process gas is CH 4 Compared to the case where the gas was included, the second region R2 was etched more at the bottom of the recess. T The reduction amounts of the SiO2 and H2O were 3.5 nm, 1.7 nm, and 1.2 nm, respectively. Therefore, the first process gas for forming the deposit DP was CO gas and H2O. 2 When a mixture of gases is used, the thickness T T The decrease in CO gas and H2 It has been confirmed that by using a mixture of gases as the first processing gas, it is possible to selectively or preferentially form a protective film having high resistance to etching of the second region R2 on the first region R1.

[0147] (Experiments 7 to 12)

[0148] In each of the seventh to twelfth experiments, a sample substrate having the same structure as the sample substrate in the first experiment was prepared. Then, a deposit DP was formed on the surface of the sample substrate using the plasma processing apparatus 1. In the seventh to twelfth experiments, the processing gas for forming the deposit DP contained CO gas and Ar gas. In the eighth to twelfth experiments, the first processing gas for forming the deposit DP contained H 2 The first treatment gas in the seventh to twelfth experiments further contained CO gas and H 2 H relative to total gas flow rate 2 The gas flow rate ratios were 0, 1 / 19, 4 / 49, 2 / 17, 1 / 4, and 5 / 14, respectively. The other formation conditions of the deposit DP in each of the seventh to twelfth experiments were the same as those of the deposit DP in the first experiment.

[0149] Figures 12(a) to 12(f) show transmission electron microscope (TEM) images of the sample substrate after the formation of the deposit DP in the seventh to twelfth experiments, respectively. The side surfaces of the deposit DP formed on the first region R1 in the eighth to tenth experiments (see Figures 12(b) to 12(d)) had higher verticality than the side surfaces of the deposit DP formed on the first region R1 in the other experiments (see Figures 12(e) to 12(f)). Therefore, the CO gas and H gas in the first process gas 2 H relative to total gas flow rate 2 It was confirmed that when the gas flow rate ratio was 1 / 19 or more and 2 / 17 or less, the verticality of the side surface of the deposit DP formed on the first region R1 increased.

[0150] Hereinafter, reference will be made to Fig. 13 and Fig. 14(a) to Fig. 14(e) together with Fig. 1. Fig. 13 is a flow chart of step STc according to an exemplary embodiment that can be employed in the etching method shown in Fig. 1. Each of Fig. 14(a) to Fig. 14(e) is a partially enlarged cross-sectional view of an example of a substrate in a state in which the corresponding step of the etching method shown in Fig. 1 has been applied. Hereinafter, a method MT including step STc shown in Fig. 13 will be described taking as an example a case in which the method is applied to the substrate W shown in Fig. 2.

[0151] The process STc shown in FIG. 13 includes a process STc1 and a process STc2. In the process STc1, as shown in FIG. 14(a), a deposit DPC is formed on the substrate W. The deposit DPC includes fluorocarbon. In the process STc1, a plasma is generated from a second process gas in a chamber of an etching apparatus to form the deposit DPC on the substrate W. The second process gas used in the process STc1 is C 4 F 6 The fluorocarbon gas contained in the second process gas used in the step STc1 is a fluorocarbon gas such as C 4 F 6 In step STc1, the fluorocarbon is supplied to the substrate W from the plasma generated from the second process gas, and the fluorocarbon forms a deposit DPC on the substrate W.

[0152] In step STc2, the second region R2 is etched by supplying ions of a rare gas to the substrate W. In step STc2, a plasma of a rare gas is formed in a chamber of an etching apparatus. The rare gas used in step STc2 is, for example, Ar gas. The rare gas used in step STc2 may be a rare gas other than Ar gas. In step STc2, ions of the rare gas are supplied from the plasma to the substrate W. The ions of the rare gas supplied to the substrate W react with the fluorocarbon contained in the deposit DPC and the material of the second region R2. As a result, in step STc2, the second region R2 is etched as shown in (b) of FIG. 14. Step STc2 is performed until the deposit DPC on the second region R2 is substantially lost. On the other hand, above the first region R1, the deposit DPC is formed on the deposit DP, and is not removed even when the ions of the rare gas are supplied.

[0153] In the process STc shown in FIG. 13, the process STc1 and the process STc2 may be alternately repeated to further etch the second region R2 as shown in FIG. 14(c). In this case, the process STc includes a process STc3. In the process STc3, it is determined whether or not a stop condition is satisfied. In the process STc3, the stop condition is satisfied when the number of times that the process STc1 and the process STc2 are alternately repeated reaches a predetermined number of times. If it is determined that the stop condition is not satisfied in the process STc3, the process STc1 and the process STc2 are executed again in order. On the other hand, if it is determined that the stop condition is satisfied in the process STc3, the process STc ends.

[0154] After the step STc is completed, the step STd may be performed. Alternatively, after the step STc is completed, it may be determined whether or not the stop condition is satisfied in the step STJ without performing the step STd. If it is determined that the stop condition is not satisfied in the step STJ, the step STb is performed again. In the step STb, as shown in (d) of FIG. 14, a deposit DP is formed on the deposit DPC on the first region R1. Then, the step STc shown in FIG. 13 is performed again, whereby the second region R2 is further etched as shown in (e) of FIG. 14.

[0155] According to the step STc shown in FIG. 13, the deposit DPC formed on the second region R2 is used for etching the second region R2 and is substantially eliminated in the step STc2. Therefore, when the step STb is performed after the step STc, the second region R2 is exposed, so that the deposit DP is selectively or preferentially formed on the deposit DPC on the first region R1 and is not formed on the second region R2. Therefore, the etching of the second region R2 is prevented from stopping in the step STc performed after the step STb. In addition, since the step STb is performed with the deposit DPC left on the first region R1, the deposit DP is sufficiently formed on the shoulder of the first region R1 of the substrate W shown in FIG. 2. Therefore, according to the method MT including the step STc shown in FIG. 13, the first region R1 is more reliably protected.

[0156] The etching apparatus used in the process STc shown in FIG. 13 may be the plasma processing apparatus 1 or the plasma processing apparatus 1B. In either case of the plasma processing apparatus 1 or the plasma processing apparatus 1B, the control unit MC brings about the process STc by bringing about a plurality of etching cycles, each of which includes a process STc1 and a process STc2. In the case where the etching apparatus used in the process STc shown in FIG. 13 is the plasma processing apparatus 1, in the process STc1, the control unit MC of the plasma processing apparatus 1 controls the gas supply unit GS to supply the second process gas into the chamber 10. In addition, in the process STc1, the control unit MC controls the exhaust unit 50 to set the pressure of the gas in the chamber 10 to a designated pressure. In addition, in the process STc1, the control unit MC controls the plasma generating unit to generate plasma from the second process gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 to supply high frequency power HF. In addition, in the process STc1, the control unit MC may control the bias power supply 64 to supply an electric bias EB. Note that the electric bias EB does not have to be supplied in the process STc1.

[0157] In step STc2, the control unit MC of the plasma processing apparatus 1 controls the gas supply unit GS to supply a rare gas into the chamber 10. Also, in step STc2, the control unit MC controls the exhaust unit 50 to set the gas pressure in the chamber 10 to a designated pressure. Also, in step STc2, the control unit MC controls the plasma generating unit to generate plasma from the rare gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 to supply high frequency power HF. Also, in step STc2, the control unit MC controls the bias power supply 64 to supply an electric bias EB.

[0158] When the etching apparatus used in the process STc shown in FIG. 13 is the plasma processing apparatus 1B, the control unit MC of the plasma processing apparatus 1B controls the gas supply unit GSB to supply a second process gas containing a fluorocarbon gas into the chamber 110. In addition, in the process STc1, the control unit MC controls the exhaust unit 150 to set the pressure of the gas in the chamber 110 to a designated pressure. In addition, in the process STc1, the control unit MC controls the plasma generating unit to generate plasma from the second process gas in the chamber 110. Specifically, the control unit MC controls the high frequency power sources 170a and 170b to supply high frequency power. In addition, in the process STc1, the control unit MC may control the bias power source 164 to supply an electric bias EB.

[0159] In step STc2, the control unit MC of the plasma processing apparatus 1B controls the gas supply unit GSB to supply a rare gas into the chamber 110. Also, in step STc2, the control unit MC controls the exhaust unit 150 to set the gas pressure in the chamber 110 to a designated pressure. Also, in step STc2, the control unit MC controls the plasma generating unit to generate plasma from the rare gas in the chamber 110. Specifically, the control unit MC controls the high frequency power supplies 170a and 170b to supply high frequency power. Also, in step STc2, the control unit MC controls the bias power supply 164 to supply an electric bias EB.

[0160] Hereinafter, an etching method according to another exemplary embodiment will be described with reference to FIG. 15. FIG. 15 is a flow chart of an etching method according to another exemplary embodiment. The etching method shown in FIG. 15 (hereinafter, referred to as "method MTB") includes a step STa, a step STe, and a step STc. In method MTB, a plurality of cycles each including a step STe and a step STc may be performed in sequence. Method MTB may further include a step STf. Each of the plurality of cycles may further include a step STf. Method MTB may further include a step STd. Each of the plurality of cycles may further include a step STd.

[0161] In the method MTB, the plasma processing apparatus 1 or the plasma processing apparatus 1B may be used. In the method MTB, another plasma processing apparatus may be used. FIG. 16 is a diagram showing a schematic diagram of a plasma processing apparatus according to another exemplary embodiment. Hereinafter, the plasma processing apparatus 1C will be described from the viewpoint of the difference between the plasma processing apparatus 1C shown in FIG. 16 and the plasma processing apparatus 1.

[0162] The plasma processing apparatus 1C includes at least one DC power supply. The at least one DC power supply is configured to apply a negative DC voltage to the upper electrode 30. When a negative DC voltage is applied to the upper electrode 30 while plasma is being generated in the chamber 10, positive ions in the plasma collide with the top plate 34. As a result, secondary electrons are emitted from the top plate 34 and supplied to the substrate. Also, silicon is emitted from the top plate 34 and supplied to the substrate.

[0163] In one embodiment, the upper electrode 30 may include an inner portion 301 and an outer portion 302. The inner portion 301 and the outer portion 302 are electrically isolated from each other. The outer portion 302 is provided radially outward from the inner portion 301 and extends in the circumferential direction so as to surround the inner portion 301. The inner portion 301 includes an inner region 341 of the top plate 34, and the outer portion 302 includes an outer region 342 of the top plate 34. The inner region 341 may have a substantially disk shape, and the outer region 342 may have a ring shape. Each of the inner region 341 and the outer region 342 is formed of a silicon-containing material, similar to the top plate 34 of the plasma processing apparatus 1.

[0164] In the plasma processing apparatus 1C, the high frequency power supply 62 supplies high frequency power HF to both the inner portion 301 and the outer portion 302. The plasma processing apparatus 1 may include a DC power supply 71 and a DC power supply 72 as at least one DC power supply. Each of the DC power supply 71 and the DC power supply 72 may be a variable DC power supply. The DC power supply 71 is electrically connected to the inner portion 301 so as to apply a negative DC voltage to the inner portion 301. The DC power supply 72 is electrically connected to the outer portion 302 so as to apply a negative DC voltage to the outer portion 302. Other configurations of the plasma processing apparatus 1C may be the same as the corresponding configurations of the plasma processing apparatus 1.

[0165] Reference will be made again to Fig. 15. Below, the method MTB will be described taking as an example the case where it is applied to the substrate W shown in Fig. 2. In the following description, further reference will be made to Fig. 17(a) to Fig. 17(d). Each of Fig. 17(a) to Fig. 17(d) is a partially enlarged cross-sectional view of an example of a substrate in a state where the corresponding step of the etching method shown in Fig. 15 has been applied.

[0166] Method MTB starts with step STa, which is the same step as step STa of method MT.

[0167] Step STe is performed after step STa. In step STe, as shown in (a) of Fig. 17, a first deposit DP1 is selectively or preferentially formed on the first region R1.

[0168] In one embodiment, the step STe may be the same as the step STb. In this case, the first deposit DP1 formed in the step STe is the same as the deposit DP. In this case, the plasma processing apparatus used in the step STe may be the plasma processing apparatus 1, the plasma processing apparatus 1B, or the plasma processing apparatus 1C.

[0169] In another embodiment, step STe may include a step of applying a negative DC voltage to the upper electrode 30 when the same step as step STb is being performed. In this case, a plasma processing apparatus 1C is used in step STe. In this case, the first deposit DP1 is formed of chemical species (e.g., carbon) from the plasma generated from the first processing gas and silicon released from the top plate 34, and becomes a dense film. In this case, the control unit MC of the plasma processing apparatus 1C further provides a step of applying a negative DC voltage to the upper electrode 30 when step STb is being performed.

[0170] In the step STe, the control unit MC controls at least one DC power supply to apply a negative DC voltage to the upper electrode 30. Specifically, the control unit MC controls the DC power supplies 71 and 72 to apply a negative DC voltage to the upper electrode 30. The absolute value of the negative DC voltage applied from the DC power supply 71 to the inner portion 301 of the upper electrode 30 may be greater than the absolute value of the negative DC voltage applied from the DC power supply 72 to the outer portion 302 of the upper electrode 30. In the step STe, the DC power supply 72 does not need to apply a voltage to the outer portion 302 of the upper electrode 30.

[0171] As described above, the method MTB may further include a step STf. The step STf is performed after the step STe and before the step STc. In the step STf, as shown in FIG. 17(b), a second deposit DP2 is formed on the substrate W. The second deposit DP2 includes silicon. The control unit MC of the plasma processing apparatus used in the step STf is configured to bring about the step STf.

[0172] In step STf, the second deposit DP2 may be formed by plasma-enhanced chemical vapor deposition (i.e., PECVD). When the second deposit DP2 is formed by PECVD, the plasma processing apparatus used in step STf may be the plasma processing apparatus 1, the plasma processing apparatus 1B, or the plasma processing apparatus 1C.

[0173] When PECVD is performed using the plasma processing apparatus 1 or 1C in the process STf, the control unit MC controls the gas supply unit GS to supply a processing gas into the chamber 10. The processing gas is SiCl 4 The process gas includes a silicon-containing gas such as H 2 The gas may further include a gas. The control unit MC also controls the exhaust device 50 to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the processing gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 to supply high frequency power HF.

[0174] When PECVD is performed using the plasma processing apparatus 1B in the process STf, the control unit MC controls the gas supply unit GSB to supply a processing gas into the chamber 110. The processing gas is SiCl 4 The process gas includes a silicon-containing gas such as H 2The gas may further include a gas. The control unit MC also controls the exhaust device 150 to set the pressure of the gas in the chamber 110 to a designated pressure. The control unit MC also controls the plasma generating unit to generate plasma from the processing gas in the chamber 110. Specifically, the control unit MC controls the high frequency power supplies 170a and 170b to supply high frequency power.

[0175] Alternatively, step STf may include a step of applying a negative DC voltage to the upper electrode 30 when plasma is generated in the chamber 10. When a negative DC voltage is applied to the upper electrode 30 when plasma is generated in the chamber 10, positive ions in the plasma collide with the top plate 34. As a result, secondary electrons are emitted from the top plate 34 and supplied to the substrate W. In addition, silicon is emitted from the top plate 34 and supplied to the substrate W. The silicon supplied to the substrate W forms a second deposit DP2 on the substrate W. In this case, the plasma processing apparatus 1C is used in step STf.

[0176] In this case, the control unit MC of the plasma processing apparatus 1C is configured to perform a process STf. In the process STf, the control unit MC controls the gas supply unit GS to supply gas into the chamber 10. The gas supplied into the chamber 10 in the process STf includes a rare gas such as Ar gas. The gas supplied into the chamber 10 in the process STf includes hydrogen gas (H 2 The control unit MC may further include a gas (a gas). The control unit MC also controls the exhaust device 50 so as to set the pressure of the gas in the chamber 10 to a designated pressure. The control unit MC also controls the plasma generating unit so as to generate plasma from the gas in the chamber 10. Specifically, the control unit MC controls the high frequency power supply 62 so as to supply high frequency power HF.

[0177] Furthermore, in step STf, the control unit MC controls at least one DC power supply to apply a negative DC voltage to the upper electrode 30. Specifically, the control unit MC controls the DC power supplies 71 and 72 to apply a negative DC voltage to the upper electrode 30. The absolute value of the negative DC voltage applied from the DC power supply 71 to the inner portion 301 of the upper electrode 30 may be greater than the absolute value of the negative DC voltage applied from the DC power supply 72 to the outer portion 302 of the upper electrode 30.

[0178] Next, in the method MTB, step STc is performed to etch the second region R2 as shown in (c) of Fig. 17. Step STc in the method MTB is the same as step STc in the method MT. The plasma processing apparatus used in step STc may be the plasma processing apparatus 1, the plasma processing apparatus 1B, or the plasma processing apparatus 1C.

[0179] In the method MTB, after the second region R2 is etched, step STd may be performed to remove the first deposit DP1 and the second deposit DP2 as shown in (d) of Fig. 17. Step STd of the method MTB is the same as step ST of the method MT. The plasma processing apparatus used in step STd may be the plasma processing apparatus 1, the plasma processing apparatus 1B, or the plasma processing apparatus 1C.

[0180] According to method MTB, a second deposit DP2 is formed on the first deposit DP1, thereby further suppressing etching of the shoulder of the first region R1 of the substrate W and suppressing widening of the opening of the recess provided by the first region R1.

[0181] As described above, the method MT may perform a plurality of cycles each including a step STe, a step STf, a step STc, and a step STd. In some of the plurality of cycles, at least one of the steps STe, STf, and STd may be omitted. The number of cycles including the step STe may be less than the number of cycles including the step STf. In this case, the number of times the step STe is performed can be reduced by performing the step STf to form the second deposit DP2 before the first deposit DP1 is consumed.

[0182] Reference is now made to Fig. 18, which is a partially enlarged cross-sectional view of yet another example substrate to which the etching methods according to various exemplary embodiments may be applied. The method MT may also be applied to the substrate WC shown in Fig. 18.

[0183] The substrate WC includes a first region R1 and a second region R2. The substrate WC may further include a third region R3 and an underlayer region UR. The third region R3 is provided on the underlayer region UR. The third region R3 is made of an organic material. The second region R2 is formed on the third region R3. The second region R2 includes silicon oxide. The second region R2 may include a silicon oxide film and a silicon carbide film provided on the silicon oxide film. The first region R1 is a mask provided on the second region R2 and is patterned. The second region R2 may be a photoresist mask. The second region R2 may be an extreme ultraviolet (EUV) mask.

[0184] Each of (a) of Figure 19 and (b) of Figure 19 is a partially enlarged cross-sectional view of an example of a substrate in a state in which a corresponding step of an etching method according to an example embodiment has been applied. When the method MT is applied to the substrate WC, in step STb, a deposit DP is selectively or preferentially formed on the first region R1 as shown in (a) of Figure 19. Then, in step STc, the second region R2 is etched as shown in (b) of Figure 19. The method MTB may be applied to the substrate WC shown in Figure 18.

[0185] Although various exemplary embodiments have been described above, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and modifications may be made. In addition, elements in different embodiments can be combined to form other embodiments.

[0186] The plasma processing apparatus used in the methods MT and MTB may be a capacitively coupled plasma processing apparatus other than the plasma processing apparatus 1. The plasma processing apparatus used in the methods MT and MTB may be an inductively coupled plasma processing apparatus other than the plasma processing apparatus 1B. The plasma processing apparatus used in the methods MT and MTB may be another type of plasma processing apparatus. Such a plasma processing apparatus may be an electron cyclotron (ECR) plasma processing apparatus or a plasma processing apparatus that generates plasma by surface waves such as microwaves.

[0187] From the foregoing, it will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims. [Explanation of symbols]

[0188] W...substrate, R1...first region, R2...second region, 1...plasma processing apparatus, 10...chamber, 14...substrate support, MC...control unit.

Claims

1. (a) providing a substrate, the substrate having a first region and a second region, the second region comprising silicon and oxygen, the first region being a mask over the second region, the first region being formed of a material different from that of the second region and not comprising oxygen; (b) selectively forming a deposit on the upper surface of the mask using a first plasma generated from a first process gas including carbon monoxide gas and a noble gas; (c) etching the second region using the mask on which the deposit is formed; An etching method comprising:

2. The (c) is (c1) forming another deposit on the substrate comprising a fluorocarbon by generating a plasma from a second process gas comprising a fluorocarbon gas; (c2) etching the second region by supplying ions from a plasma generated from a noble gas to the substrate on which the further deposit is formed; The etching method of claim 1 , comprising:

3. The etching method according to claim 1 or 2, wherein the steps (b) and (c) are repeated alternately.

4. 4. The etching method according to claim 1, wherein the steps (b) and (c) are carried out in the same chamber.

5. (b) is carried out in a first chamber; (c) is carried out in a second chamber; The etching method according to any one of claims 1 to 3.

6. further comprising, between (b) and (c), transferring the substrate from the first chamber to the second chamber in a vacuum environment; The etching method according to claim 5 .

7. An etching method according to claim 1, wherein the flow rate of the carbon monoxide gas in the first processing gas is 30 sccm or more and 200 sccm or less.

8. An etching method according to claim 1, wherein the flow rate of the noble gas in the first processing gas is 1000 sccm or less.

9. An etching method described in any one of claims 1 to 8, wherein the first processing gas contains the carbon monoxide gas and the noble gas as a first gas, and a gas containing carbon and fluorine or hydrogen as a second gas.

10. The etching method of claim 9, wherein the second gas comprises a hydrofluorocarbon gas, a fluorocarbon gas, or a hydrocarbon gas.

11. a chamber having a gas inlet and a gas outlet; a substrate support disposed within the chamber; an upper electrode provided above the substrate support; a radio frequency power source configured to provide radio frequency power to generate a plasma within the chamber; a bias power supply configured to provide an electrical bias to the substrate support; A control unit; Equipped with The control unit (a) providing a substrate, the substrate having a first region and a second region, the second region comprising silicon and oxygen, the first region being a mask over the second region, the first region being formed of a material different from that of the second region and not comprising oxygen; (b) selectively forming a deposit on the upper surface of the mask using a first plasma generated from a first process gas including carbon monoxide gas and a noble gas; (c) etching the second region using the mask on which the deposit is formed; is configured to bring about Plasma processing equipment.

12. the high frequency power supply is connected to the upper electrode; the control unit is configured to supply the high-frequency power from the high-frequency power source to the upper electrode at the time of (b). The plasma processing apparatus according to claim 11 .

13. the high frequency power source is connected to the substrate support; the control unit is configured to supply the high frequency power from the high frequency power source to the substrate support at the time of (b). The plasma processing apparatus according to claim 11 .

14. 14. The plasma processing apparatus according to claim 11, wherein the control unit is configured to supply the electric bias from the bias power supply to the substrate support at the time (c).

15. The control unit The plasma processing apparatus according to any one of claims 11 to 14, further comprising: (d) a step of alternately repeating (b) and (c).

16. a chamber having a gas inlet and a gas outlet; a substrate support disposed within the chamber; an antenna provided above the substrate support; a radio frequency power source configured to provide radio frequency power to generate a plasma within the chamber; a bias power supply configured to provide an electrical bias to the substrate support; A control unit; Equipped with The control unit (a) providing a substrate, the substrate having a first region and a second region, the second region comprising silicon and oxygen, the first region being a mask over the second region, the first region being formed of a material different from that of the second region and not comprising oxygen; (b) selectively forming a deposit on the upper surface of the mask using a first plasma generated from a first process gas including carbon monoxide gas and a noble gas; (c) etching the second region using the mask on which the deposit is formed; The plasma processing apparatus is configured to provide

17. the high frequency power source is connected to the antenna; The control unit is configured to supply the high-frequency power from the high-frequency power source to the antenna at the time of (b). The plasma processing apparatus according to claim 16.

18. 18. The plasma processing apparatus according to claim 16, wherein the control unit is configured to supply the electric bias from the bias power supply to the substrate support at the time (c).

Images