Plasma processing method and plasma processing apparatus

Abstract

The present invention provides a technique for stabilizing the performance of film formation processing using plasma. A plasma processing method includes a step a), a step b), and a step c). In the step a), a substrate having a recess is provided into a processing vessel. In the step b), plasma is generated in the processing vessel, and a film is formed on the recess. In the step c), the state of the plasma generated in the step b) is monitored. Based on the monitored state of the plasma, it is determined whether the step b) is to be performed again and the processing conditions at the time of the re-performance.

Description

Technical Field

[0001] This invention relates to plasma processing methods and plasma processing apparatus. Background Technology

[0002] As semiconductor device integration progresses not only horizontally but also vertically, the aspect ratio of patterns formed during semiconductor device manufacturing is increasing. For example, in the manufacturing of 3D NAND, channel holes are formed in directions that penetrate multiple metal wiring layers. In the case of forming 64 memory cells, the aspect ratio of the channel holes is 45.

[0003] Various methods have been proposed to form high aspect ratio patterns with high precision. For example, a method has been proposed to suppress lateral etching by repeatedly etching and depositing film on openings in the dielectric material formed on a semiconductor substrate (Patent Document 1). In addition, a method has been proposed to combine etching and film deposition to form a protective film for preventing lateral etching of the dielectric layer (Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent Application Publication No. 2016 / 0343580

[0007] Patent Document 2: U.S. Patent Application Publication No. 2018 / 0174858 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] This invention provides a technique that enables the performance of plasma-based film formation processes to be stabilized.

[0010] Methods for solving problems

[0011] One aspect of the plasma processing method implemented by the plasma processing apparatus of the present invention includes steps a), b), and c). In step a), a substrate having a recess is provided into a processing container. In step b), plasma is generated within the processing container, and a film is formed on the recess. In step c), the state of the plasma generated in step b) is monitored. Based on the monitored state of the plasma, it is determined whether step b) should be repeated and the processing conditions for re-enactment.

[0012] The effects of the invention

[0013] According to the present invention, the performance of film-forming processes utilizing plasma can be stabilized. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating an example of the structure of a plasma processing system according to one embodiment.

[0015] Figure 2 This is a diagram illustrating an example of the structure of a plasma processing apparatus according to one embodiment.

[0016] Figure 3 This is a flowchart illustrating the general process of plasma processing in one embodiment.

[0017] Figure 4 This is a diagram illustrating an example of the process of subconformal atomic layer deposition (ALD).

[0018] Figure 5 This is another example of a process used to illustrate subconformal ALD.

[0019] Figure 6 This is a flowchart for further illustrating a plasma processing method in one embodiment.

[0020] Figure 7 This is a flowchart illustrating the monitoring and judgment processes of one implementation method.

[0021] Figure 8 This is a diagram used to illustrate the monitoring results obtained in the monitoring process of one implementation method.

[0022] Figure 9A This is a diagram illustrating Example 2 of a method for detecting physical quantities in a monitoring process of one implementation.

[0023] Figure 9B This indicates that it will be passed Figure 9A Example 2 shows an example of image numericalization obtained using the method described.

[0024] Figure 10 It means based on Figure 9A and Figure 9B Example 2 is a flowchart of the monitoring and processing flow.

[0025] Figure 11 This diagram illustrates an example of information stored in a storage unit during plasma processing in one embodiment.

[0026] Explanation of reference numerals in the attached figures

[0027] 1. Plasma processing device

[0028] 10. Handling Containers

[0029] 15 Gas supply sources

[0030] 20 mounting platforms

[0031] 25 Gas Nozzle

[0032] 32 Second High-Frequency Power Supply

[0033] 34 First High-Frequency Power Supply

[0034] 100 Control Department

[0035] 103 Focusing ring

[0036] 106 Electrostatic Chuck

[0037] 108 optical sensors

[0038] 108a First Sensor

[0039] 108b Second Sensor

[0040] 1000 plasma processing system

[0041] OC observation device

[0042] EL1 Etching of the target film

[0043] F membrane

[0044] MA mask

[0045] OP opening

[0046] P precursor

[0047] R Reaction Gas

[0048] W chip Detailed Implementation

[0049] Hereinafter, the disclosed embodiments will be described in detail based on the accompanying drawings. However, these embodiments are not limited thereto. Furthermore, the various embodiments can be appropriately combined without contradicting the processing content. Additionally, the same or equivalent parts are labeled with the same reference numerals in the various drawings.

[0050] Furthermore, in the following description, "pattern" refers to all shapes formed on the substrate. A pattern, for example, refers to a collection of multiple shapes formed on the substrate, such as holes, trenches, line widths, and line spacings. Additionally, "recess" refers to a portion of a pattern formed on the substrate that is recessed in the thickness direction of the substrate. Furthermore, a recess has a "sidewall" as the inner peripheral surface of the recessed shape, a "bottom" as the bottom portion of the recessed shape, and a "top" as the substrate surface near the sidewall, which is continuous with the sidewall. The space enclosed by the top is called an "opening." Moreover, the term "opening" refers to the entire space enclosed by the bottom and sidewall of the recess, or any location within that space.

[0051] It is known that shape anomalies are easily generated when forming deep holes with high aspect ratios, such as HARC (High Aspect Ratio Contact). For example, a shape anomaly known as a bowing is known. A bowing refers to a shape anomaly where the inner circumferential surface of the opening bulges out in a barrel shape in the transverse direction when the opening is formed longitudinally. In this embodiment, a film is formed on the sidewall of the opening to suppress the generation of shape anomalies such as bowing. Film formation methods include, for example, atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), and plasma-enhanced cyclic chemical vapor deposition (PECCVD).

[0052] (Structural example of the plasma processing system according to the embodiment)

[0053] Figure 1 This is a diagram illustrating an example of a plasma processing system that can be used in the implementation of the plasma processing described in the embodiment.

[0054] Figure 1 The plasma processing system 1000 shown includes: a control unit Cnt, stages 1122a, 1122b, 1122c, and 1122d, storage containers 1124a, 1124b, 1124c, and 1124d, a loader module LM, load lock chambers LL1 and LL2, a transfer chamber 1121, and a plasma processing device 1010. The plasma processing device 1010 can be, for example, a... Figure 2 The plasma processing device 1 shown.

[0055] The control unit Cnt is a computer including a processor, storage unit, input device, display device, etc., which controls the various parts of the plasma processing system 1000 described later. The control unit Cnt is connected to the conveying robotic arm Rb1, conveying robotic arm Rb2, observation device OC, plasma processing device 1010, etc. The control unit Cnt can also function as... Figure 2 The control unit 100 of the plasma processing device 1 shown.

[0056] The control unit Cnt operates according to the computer program (input-based program) for controlling each part of the plasma processing system 1000 and issues control signals. Through the control signals from the control unit Cnt, each part of the plasma processing system 1000, such as the transport robotic arms Rb1 and Rb2, the observation device OC, and each part of the plasma processing apparatus 1010, is controlled. In the plasma processing apparatus 1010, through the control signals from the control unit Cnt, the selection and flow rate of the gas supplied from the gas supply source 15, the exhaust from the exhaust device 65, the power supply from the high-frequency power supplies 32 and 34, the refrigerant flow rate, and the refrigerant temperature can be controlled. Furthermore, each step of the substrate processing method of the first and second embodiments described above can be executed by operating each part of the plasma processing system 1000 through the control of the control unit Cnt. The storage unit of the control unit Cnt readablely stores the computer program for executing the plasma processing method of the embodiments and various data used in execution.

[0057] Stages 1122a to 1122d are arranged along one edge of the loader assembly LM. Receiving containers 1124a to 1124d are each disposed on each stage 1122a to 1122d. The wafer W is housed within the receiving containers 1124a to 1124d.

[0058] A transport robotic arm Rb1 is provided within the loader assembly LM. The transport robotic arm Rb1 retrieves the wafer W stored in any of the storage containers 1124a to 1124d and transports the wafer W to the loading locking chamber LL1 or LL2.

[0059] Loading and locking chambers LL1 and LL2 are disposed along the other edge of the loader assembly LM and connected to the loader assembly LM. Loading and locking chambers LL1 and LL2 constitute a pre-decompression chamber. Loading and locking chambers LL1 and LL2 are each connected to the transfer chamber 1121.

[0060] The transfer chamber 1121 is a depressurized chamber, and a transfer robotic arm Rb2 is installed inside the transfer chamber 1121. The transfer chamber 1121 is connected to the plasma processing apparatus 1010. The transfer robotic arm Rb2 removes the wafer W from the loading and locking chamber LL1 or the loading and locking chamber LL2 and transfers the wafer W to the plasma processing apparatus 1010.

[0061] The plasma processing system 1000 includes an observation device OC. The observation device OC can be installed anywhere within the plasma processing system 1000. In one example, the observation device OC is installed within an observation assembly OM adjacent to the loader assembly LM. A wafer W can be moved between the observation assembly OM and the plasma processing apparatus 1010 via transport robotic arms Rb1 and Rb2. The wafer W is housed within the observation assembly OM by the transport robotic arm Rb1. After positioning the wafer W within the observation assembly OM, the observation device OC measures the groove width of a mask or similar pattern on the wafer W and sends the measurement result to the control unit Cnt. The observation device OC can measure the groove width of a mask or similar pattern formed on multiple regions of the wafer W's surface. The measurement result of the observation device OC is, for example, referred to as the "detection result" in the embodiments described later (see reference). Figure 11 It can be used as an observation device, for example, with optical observation devices, weighing scales, ultrasonic microscopes, etc.

[0062] (Structural example of the plasma processing apparatus according to the embodiment)

[0063] Reference Figure 2 This invention describes a plasma processing apparatus 1 according to one embodiment of the present invention. Figure 2 An example of the structure of the plasma processing apparatus 1 of this embodiment is shown in longitudinal section. The plasma processing apparatus 1 of this embodiment is a parallel-plate type plasma processing apparatus (capacitively coupled plasma processing apparatus) in which a stage 20 and a gas nozzle 25 are arranged opposite each other within a processing container 10. The stage 20 functions to hold the semiconductor substrate (hereinafter referred to as "wafer W") and acts as a lower electrode. The gas nozzle 25 functions to supply gas into the processing container 10 in a spray pattern and acts as an upper electrode.

[0064] The processing container 10 is made of, for example, aluminum with an acid-resistant aluminum treatment (anodization) and is cylindrical in shape. The processing container 10 is electrically grounded. A stage 20 is disposed at the bottom of the processing container 10 and holds the wafer W. The wafer W is an example of a substrate intended for plasma processing.

[0065] The mounting stage 20 is formed of materials such as aluminum (Al), titanium (Ti), and silicon carbide (SiC). An electrostatic chuck 106 for electrostatically adsorbing the substrate is provided on the upper surface of the mounting stage 20. The electrostatic chuck 106 is constructed by sandwiching chuck electrodes 106a between insulators 106b.

[0066] The chuck electrode 106a is connected to a DC voltage source 112, from which a DC current is supplied to the chuck electrode 106a. Thus, the wafer W is attracted to the electrostatic chuck 106 by Coulomb force.

[0067] An annular focusing ring 103 is mounted on the electrostatic chuck 106 to surround the periphery of the wafer W. The focusing ring 103 is made of a conductive material such as silicon and causes the plasma to converge toward the surface of the wafer W inside the processing container 10, thereby improving the etching efficiency.

[0068] The stage 20 is supported by a support body 104. A refrigerant flow path 104a is formed inside the support body 104. The refrigerant flow path 104a is connected to a refrigerant inlet pipe 104b and a refrigerant outlet pipe 104c. A cooling medium, such as cooling water or brine, output from the cooler 107 circulates through the refrigerant inlet pipe 104b, the refrigerant flow path 104a, and the refrigerant outlet pipe 104c. As a result, the stage 20 and the electrostatic chuck 106 are cooled.

[0069] A heat transfer gas supply source 85 supplies heat transfer gases such as helium (He) and argon (Ar) to the back side of the wafer W on the electrostatic chuck 106 via a gas supply line 130. According to this configuration, the electrostatic chuck 106 is temperature-controlled by a cooling medium circulating in a refrigerant flow path 104a and the heat transfer gas supplied to the back side of the wafer W. As a result, the substrate can be controlled at a predetermined temperature.

[0070] The first high-frequency power supply 34 is electrically connected to the gas nozzle 25 via a matching connector 35. The first high-frequency power supply 34 applies, for example, a 60 MHz plasma excitation high-frequency power HF to the stage 20. Furthermore, in this embodiment, the high-frequency power HF is applied to the gas nozzle 25, but it can also be applied to the stage 20. The second high-frequency power supply 32 is electrically connected to the stage 20 via a matching connector 33. The second high-frequency power supply 32 applies, for example, a 13.56 MHz bias high-frequency power LF to the stage 20.

[0071] Matching unit 35 matches the load impedance to the internal (or output) impedance of the first high-frequency power supply 34. Matching unit 33 matches the load impedance to the internal (or output) impedance of the second high-frequency power supply 32. Matching units 35 and 33 function to ensure that the internal impedances and load impedances of the first high-frequency power supply 34 and the second high-frequency power supply 32 are visually identical when plasma is generated within the processing container 10.

[0072] The gas nozzle 25 includes a top electrode plate 41 with multiple gas supply holes 55 and a heat sink 42 that detachably suspends the top electrode plate 41. The gas nozzle 25 is mounted to close the opening of the top surface of the processing container 10 with a shielding ring 40 covering its periphery. A gas inlet 45 is formed in the gas nozzle 25 for introducing gas. Inside the gas nozzle 25, a diffusion chamber 50a on the central side and a diffusion chamber 50b on the edge side branch from the gas inlet 45 are provided. Gas output from the gas supply source 15 is supplied to the diffusion chambers 50a and 50b via the gas inlet 45, and diffuses in the respective diffusion chambers 50a and 50b before being introduced into the stage 20 through the multiple gas supply holes 55.

[0073] An exhaust port 60 is formed on the bottom surface of the processing container 10, and exhaust device 65 connected to the exhaust port 60 vents the contents of the processing container 10. This allows the processing container 10 to maintain a predetermined vacuum level. A gate valve G is provided on the side wall of the processing container 10. The wafer W is fed into and out of the processing container 10 by opening and closing the gate valve G.

[0074] A light sensor 108 is installed in the plasma processing apparatus 1, capable of measuring the intensity of light of various wavelengths in the plasma within the processing container 10 through a quartz window 109. The light sensor 108 includes a first sensor 108a and a second sensor 108b. The first sensor 108a detects the state of the plasma generated within the processing container 10. The detection result of the first sensor 108a is used in the monitoring and judgment processes described later. Additionally, the second sensor 108b detects the pattern shape on the surface of the wafer W placed on the stage 20. The detection result of the second sensor 108b is used in the first to third detection processes described later.

[0075] The plasma processing apparatus 1 is equipped with a control unit 100 that controls the operation of the entire apparatus. The control unit 100 is connected to a CPU (Central Processing Unit) 105, a ROM (Read Only Memory) 110, and a RAM (Random Access Memory) 115. The CPU 105 executes desired processes, such as film formation processing, monitoring processing, judgment processing, etching processing, and the first to third detection processes, according to various schemes stored in the aforementioned storage area. The schemes record control information for the apparatus regarding processing conditions, such as processing time, pressure (gas exhaust), high-frequency power, voltage, various gas flow rates, temperature inside the processing container 10 (top electrode temperature, side wall temperature of the processing container, electrostatic chuck temperature, etc.), and temperature of the cooler 107. Furthermore, the schemes representing the above-mentioned programs and processing conditions can be stored in a hard disk or semiconductor memory. Alternatively, the schemes can be installed in a predetermined location in the storage area while stored in a removable computer-readable storage medium such as a CD-ROM or DVD.

[0076] The control unit 100 performs monitoring processing, which causes the first sensor 108a to monitor the state of the plasma within the processing container 10 (described later). Additionally, the control unit 100 performs judgment processing, based on the detection results of the first sensor 108a, to determine whether the film deposition process should be repeated and to determine the processing conditions for re-enactment (described later). Furthermore, the control unit 100 performs first to third detection processes, based on the detection results of the second sensor 108b, to detect the pattern shape of the wafer W (described later).

[0077] During plasma processing, the opening and closing of the gate valve G is controlled to feed the wafer W into the processing container 10 and place it on the stage 20. A DC current is supplied to the chuck electrode 106a from the DC voltage source 112, thereby attracting and holding the wafer W to the electrostatic chuck 106 by Coulomb force.

[0078] Next, plasma processing gas, plasma excitation power HF, and bias power LF are supplied to the processing container 10 to generate plasma. The generated plasma is then used to perform plasma processing (e.g., film deposition, etching) on ​​the wafer W.

[0079] After plasma treatment, a DC voltage HV, opposite in polarity to that applied to the chuck electrode 106a during wafer W adsorption, is applied from the DC voltage source 112 to remove the charge from the wafer W, causing it to peel off from the electrostatic chuck 106. The opening and closing of the gate valve G can be controlled to eject the wafer W from the processing container 10.

[0080] (ALD and Subconformal ALD)

[0081] In this embodiment, a plasma-based process is performed as the film-forming process. There are no particular limitations on the type of film-forming process; any process using plasma is acceptable. For example, PEALD, PECVD, PECCVD, etc., described above, can be used.

[0082] First, refer to Figures 3-5 Explain ALD and subconformal ALD. Figure 3 This is a flowchart illustrating the general process of plasma processing in one embodiment. Figure 3 The processing flow shown is shared with both ALD and subconformal ALD cases. Figure 4 This is a diagram illustrating an example of the process for subconformal ALD. Figure 5 This is another example of a process used to illustrate subconformal ALD.

[0083] First, a patterned wafer W is provided in the processing container 10 (step S11). The wafer W is automatically fed in through the gate valve G by the transport robotic arm Rb2. Then, a first gas (also called a precursor) is introduced from the gas supply source 15 into the processing container 10 in which the wafer W is disposed (step S12). The first component contained in the first gas is adsorbed onto the surface of the wafer W. Then, the processing container 10 is purged using the venting device 65 (step S13). Next, a second gas (also called a reactant gas) containing a second component to react with the first component is introduced from the gas supply source 15 into the processing container 10, generating plasma of the second gas (step S14). The second component reacts with the first component on the wafer W to form a film. Afterward, the processing container 10 is purged again using the venting device 65 (step S15). After the film formation performed in steps S12 to S15, the control unit 100 further performs processes such as etching (step S16). Then, the control unit 100 terminates the processing of each part of the plasma processing device 1.

[0084] Furthermore, here, an apparatus for performing each process within a plasma processing apparatus 1 is described. However, in the case where the plasma processing system 1000 has multiple plasma processing apparatuses 1010, the processes can be performed within a plasma processing apparatus 1010 that is different from the film formation process and the etching process.

[0085] Alternating current (ALD) forms a film through the controlled adsorption and reaction of substances with predetermined components pre-existing on the substrate surface. Therefore, ALD typically achieves conformal film formation by setting sufficient processing time. Figure 3In this case, the processing time for steps S12 and S14 is made sufficiently long. That is, the processing conditions for steps S12 and S14 are set to saturation conditions. As a result, the adsorption of the first gas on the components of the wafer W and the reaction of the components of the first gas with the components of the second gas reach saturation on the surface of the wafer W, forming a conformal film. A conformal film is a film with the same thickness regardless of its position on the wafer W (e.g., its position in the vertical direction).

[0086] To address this, the subconformal ALD is controlled to use the same processing steps as the ALD, ensuring that at least one of the adsorption and reaction of the film-forming components does not reach saturation. That is, the subconformal ALD uses the same processing steps as the ALD, but does not allow self-controlled adsorption or reaction to occur on the surface of the wafer W, thereby forming a subconformal film. A subconformal film is one whose thickness varies depending on its position on the wafer W (e.g., vertical position).

[0087] There are at least two ways to handle subconformal ALD.

[0088] (1) The precursor is adsorbed onto the entire surface of the wafer W. Control is performed so that the subsequently introduced reactive gas does not spread throughout the entire surface of the wafer W.

[0089] (2) The precursor is adsorbed only on a portion of the surface of wafer W. The subsequently introduced reactive gas forms a film only on the surface portion where the precursor is adsorbed.

[0090] Using the method described in (1) or (2) above, a film with a thickness that gradually decreases from top to bottom can be formed on the sidewall of the pattern formed on the wafer W.

[0091] Figure 4 The wafer W shown includes an etch target film EL1 and a mask MA. A recess with an opening OP is formed in the stack of the etch target film EL1 and the mask MA.

[0092] First, a wafer W is provided within the processing container 10. Figure 3 Step S11). Then, the precursor P is introduced into the processing container 10 configured with the wafer W. Figure 4 (A) Figure 3 Step S12). Sufficient processing time is provided for the adsorption of precursor P, thereby allowing precursor P to adsorb onto the entire surface of wafer W. Figure 4 (B)). Once the adsorption of precursor P is complete, the processing container 10 is purged. Then, the reaction gas R is introduced into the processing container 10. Figure 4 (C) Figure 3Step S14). The introduced reactive gas R reacts with the precursor P on the wafer W to gradually form a film F from above the mask MA. Here, the reactive gas R is purged before the formation of film F reaches below the etch target film EL1. By performing the process as described above using the ALD method, it is possible to form film F not entirely on the sidewalls of the recess, but only on the upper part of the mask MA and the etch target film EL1. Figure 4 (D)). In Figure 4 In (D), the membrane F is formed above and at the top of the sidewall of the recess, but not below and at the bottom.

[0093] Next, refer to Figure 5 Explain the second method. Figure 5 The chip W shown is with Figure 4 The wafer W has the same shape.

[0094] exist Figure 5 In the example, the precursor P is adsorbed only on the upper part of the wafer W. Figure 5 (A)). After purging the precursor P, the reactant gas R is introduced into the processing vessel 10. Figure 5 (B)). At this time, the reactive gas R reacts only at the site where the precursor P is adsorbed to form a film. Therefore, the film F is formed only above the pattern of the wafer W. Figure 5 (C)).

[0095] (Processing conditions used for selecting adsorption and reaction)

[0096] Figure 4 It is executed under unsaturated conditions. Figure 3 The situation in step S14. Additionally... Figure 5 It is executed under unsaturated conditions. Figure 3 The situation in step S12.

[0097] When the processing times in steps S12 and S14 are sufficiently long, the formed film becomes conformal rather than subconformal. Therefore, in subconformal ALD, the processing conditions are set such that at least one of the adsorption and reaction of the film-forming components does not reach saturation.

[0098] To achieve subconformal ALD, processing parameters are adjusted, such as the temperature of the stage 20 on which the wafer W is placed, the pressure inside the processing container 10, the flow rate and introduction time of the precursor to be introduced, the flow rate and introduction time of the reactant gas to be introduced, and the processing time. Furthermore, in the case of plasma processing, the film deposition position can also be adjusted by adjusting the value of the high-frequency (RF) power applied for plasma generation. Figure 3 In the case of the process, the second gas is plasmaized in step S14, but the first gas can also be plasmaized in step S12.

[0099] (An example of the flow chart of a plasma processing method according to one embodiment)

[0100] Figure 6 This is a flowchart for further illustrating a plasma treatment method according to one embodiment. The plasma treatment method of this embodiment monitors the plasma during film formation processing (…). Figure 3 The state of the plasma generated in steps S12 to S15) is used to achieve high-precision determination of the end time of the film formation process.

[0101] First, a wafer W is provided within the processing container 10 (step S61). A pattern is pre-formed on the wafer W. For example, a pattern is formed on the wafer W. Figure 4 , Figure 5 The same recess. Furthermore, if both etching and film formation can be performed within the plasma processing apparatus 1, the formation of the recess can also be performed within the plasma processing apparatus 1.

[0102] Next, the plasma processing apparatus 1 performs a first detection process (step S62). The first detection process involves the second sensor 108b or the observation device OC detecting the pattern shape on the wafer W. Based on the detection result, the control unit 100 determines the processing conditions for the subsequent film deposition process (step S63). Furthermore, the pattern shape includes the aspect ratio of the recesses, the surface profile, etc. The first detection process can be performed either before or after the process of providing the wafer W (step S61) before the film deposition process (step S63). The processing conditions for the film deposition process (step S63) include, for example, the amount of first gas introduced, the amount of second gas introduced, the reaction time of the first and second gases, the purging time, and the number of cycles. The first detection process will be described later.

[0103] Based on the processing conditions determined by the first detection process, the control unit 100 sends instructions to each part of the plasma processing apparatus 1 to start the film formation process (step S63). First, the control unit 100 introduces a first gas from the gas supply source 15 into the processing container 10 (step S631). When the processing time determined by the processing conditions has elapsed, the control unit 100 stops the introduction of the first gas. The first gas is adsorbed onto the surface of the wafer W on the stage 20.

[0104] Next, the control unit 100 controls the exhaust device 65 to purge the gas in the processing container 10 (step S632).

[0105] Next, the control unit 100 introduces the second gas into the processing container 10 from the gas supply source 15 (step S633). The control unit 100 also applies high-frequency power HF for plasma excitation to the gas nozzle 25 from the first high-frequency power source 34. The control unit 100 also applies high-frequency power LF to the mounting stage 20 from the second high-frequency power source 32. In addition, high-frequency power HF can be applied to the mounting stage 20. By applying high-frequency power LF and HF, plasma of the second gas is generated in the processing container 10. Then, when the processing time based on the processing conditions determined by the first detection process has elapsed, the control unit 100 terminates the introduction of the second gas and the generation of plasma. The components contained in the plasma of the second gas react with the components of the first gas on the surface of the wafer W to form a film on the surface of the wafer W.

[0106] During the introduction of the second gas, the control unit 100 performs monitoring processing in parallel (step S64A). The monitoring processing involves the first sensor 108a monitoring the state of the plasma within the processing container 10 and sending the monitoring results to the control unit 100 for storage. Details of the monitoring processing will be described later.

[0107] Next, the control unit 100 controls the exhaust device 65 to purge the gas inside the processing container 10 (step S634). Here, one cycle of film formation processing (step S63) ends.

[0108] The control unit 100 then performs a judgment process (step S64B) based on the monitoring results of the monitoring process (step S64A). The judgment process is a process by which the control unit 100 determines subsequent processing and processing conditions based on the monitoring results sent from the first sensor 108a. The judgment process can be performed in each cycle of the film formation process (step S63), or it can be performed after a predetermined number of cycles of the film formation process (step S63).

[0109] During the judgment process, the control unit 100 decides whether to perform the film-forming process again. Furthermore, if the control unit 100 decides to perform the film-forming process again, it decides whether to repeat the process from the introduction of the first gas (step S631) or from the introduction of the second gas (step S633). Additionally, if the control unit 100 decides to perform the film-forming process again, it selects the processing conditions for the film-forming process (step S63).

[0110] In addition, Figure 6 In the process, a judgment process (step S64B) is performed after purging (step S634), but the judgment process (step S64B) can also be performed before purging or in parallel with purging.

[0111] The control unit 100 continues processing based on the judgment result in the judgment process. If it is determined that the process will be repeated from step S631 (step S64B, repeat S631), the control unit 100 repeatedly performs the above-described steps S631 to S634. On the other hand, if it is determined that the process will be repeated from step S633 (step S64B, repeat S633), the control unit 100 repeatedly performs the above-described steps S633 to S634. In addition, if it is determined that the film formation process will not be performed again (step S64B, do not perform again), the control unit 100 proceeds to the second detection process (step S65).

[0112] The second detection process is similar to the first detection process, in which the second sensor 108b or the observation device OC detects the pattern shape on the wafer W. Based on the detection result, the control unit 100 determines the subsequent processing (film formation (step S63) or etching (step S66)) and the processing conditions. The processing conditions for etching (step S66) include the amount of etching gas introduced, high-frequency power, and substrate temperature. The second detection process will be described later.

[0113] If it is determined that the film formation process will be executed again in the second detection process (step S65, execute again), the control unit 100 returns to step S63 and repeats the process. On the other hand, if it is determined that the film formation process in the second detection process will not be executed again (step S65, do not execute again), the control unit 100 performs etching under the determined processing conditions (step S66). At this time, similar to the second gas introduction, the control unit 100 can perform the monitoring process in parallel.

[0114] At the end of etching, the control unit 100 performs a third detection process (step S67). Similar to the first and second detection processes, the third detection process involves the second sensor 108b or the observation device OC detecting the pattern shape on the wafer W. Based on the detection results, the control unit 100 determines subsequent processing and processing conditions. The third detection process will be described later.

[0115] In the third detection process, if it is determined that the film deposition process needs to be performed again (step S67, film deposition is performed again), the control unit 100 returns to step S63 and repeats the process. Additionally, in the third detection process, if it is determined that the etching process needs to be performed again (step S67, etching is performed again), the control unit 100 returns to step S66 and repeats the process. On the other hand, in the third detection process, if it is determined that the film deposition process and etching process should not be performed again (step S67, not performed again), the control unit 100 terminates the process. Here, the plasma treatment of this embodiment ends.

[0116] (Monitoring / Judgment Processing)

[0117] Next, the monitoring process in step S64A and the judgment process in step S64B will be explained. Figure 7 This is a flowchart illustrating the monitoring and judgment processes of one embodiment. In the plasma processing of this embodiment, the control unit 100 monitors the state of the plasma generated during the film formation process through monitoring processing. Then, based on the results of the monitoring processing, the control unit 100 performs judgment processing to determine the time to end the film formation process.

[0118] The monitoring process (step S64A) is performed in parallel with the plasma formation process (step S63) in which the second gas is introduced into the processing container 10 to induce plasma formation. Here, the monitoring process is the process that begins at the start of the processing of a wafer W.

[0119] When the processing of wafer W begins, the control unit 100 activates the first sensor 108a to monitor the processing. The first sensor 108a detects the state of the plasma within the processing container 10 when the second gas is introduced into the processing container 10 and step S633 begins (step S71). Furthermore, the timing of the first sensor 108a's activation is not particularly limited; the control unit 100 can control the first sensor 108a to start the processing based on the processing scheme of wafer W. During monitoring, the first sensor 108a monitors, for example, the amount of free radicals generated by the plasma generated by the second gas.

[0120] However, the coverage area of ​​the film formed on the pattern during the film-forming process is determined by the temperature inside the processing container 10, the aspect ratio of the pattern to be processed, and the dose of free radicals generated inside the processing container 10. In the film-forming process of this embodiment, the temperature inside the processing container 10 is controlled by predetermined processing conditions, and the aspect ratio of the pattern can be derived in advance based on design values. Therefore, when the dose of free radicals in the film-forming process is known, the coverage area of ​​the film formed by the film-forming process can be estimated. Furthermore, here, coverage area refers to the thickness of the formed film and the state of the film including the location. For example, coverage area refers to the variation in film thickness corresponding to the aspect ratio.

[0121] The amount of free radicals contained in plasma can be estimated from the plasma's electron density, ion density, etc. Therefore, instead of directly monitoring the amount of free radicals, it is sufficient to monitor other physical quantities that represent the state of the plasma. Examples of physical quantities that represent the state of plasma include electron density, ion density, molecular / free radical density, and atomic / molecular / ionic mass.

[0122] The physical quantities representing the state of the plasma described above can be measured using spectroscopic methods (including methods utilizing lasers), interferometry, reflection methods, etc. Spectroscopic methods include emission spectrometry, which measures the intensity of emitted light beams, emission spectra, and continuous spectrum intensity. Absorption spectrometry, such as total absorption, self-absorption, and hook methods, can also be used. Furthermore, laser-based spectroscopic methods can be employed. For example, laser organic fluorescence, laser absorption spectrometry, and laser scattering methods can be used. Other methods include microwave interferometry / reflection methods, laser interferometry / polarization methods, and schlieren / shadow graph methods.

[0123] The first sensor 108a is a detection device capable of monitoring physical quantities representing the state of the plasma. The specific structure of the first sensor 108a is not particularly limited as long as it can monitor physical quantities representing the state of the plasma. For example, an optical emission spectroscopy (OES) sensor can be used as the first sensor 108a. Alternatively, an ultra-high resolution image sensor can be used as the first sensor 108a. Furthermore, the physical quantities can be calculated by analyzing the information acquired by the first sensor 108a, such as an image, through the control unit 100.

[0124] The first sensor 108a monitors a physical quantity representing the state of the plasma generated in step S633 and sends the monitoring result to the control unit 100. The control unit 100 stores the received monitoring result in accordance with the time.

[0125] The control unit 100 determines whether the film-forming process (steps S631 to S634) has ended (step S72). If it is determined that the film-forming process has not ended (step S72, "No"), the control unit 100 returns to step S71 and continues the monitoring process performed by the first sensor 108a. On the other hand, if it is determined that the film-forming process has ended (step S72, "Yes"), the control unit 100 proceeds to step S73 to perform the determination process.

[0126] (Judgment and processing)

[0127] During the judgment process, the control unit 100 calculates the integral value of the physical quantity at each moment obtained through the monitoring process. The physical quantities obtained through the monitoring process are stored in the control unit 100 corresponding to the time. Figure 8 This is a diagram used to illustrate the monitoring results obtained in the monitoring process of one implementation method. Figure 8 In this example, the first sensor 108a monitors the amount of free radicals in the plasma at predetermined intervals (t1, t2, t3…) and sends the numerical values ​​to the control unit 100. Here, the monitored amount of free radicals is depicted… Figure 8The curve changes. The control unit 100 calculates the integral value of the monitoring results from the start of processing of the chip W to that moment. Figure 8 In the example, the control unit 100 calculates the value obtained by adding S1, S2, S3... together.

[0128] Next, the control unit 100 determines whether the calculated integral value is above a predetermined value (step S73). Here, the "predetermined value" is calculated in advance based on the aspect ratio of the pattern on the wafer W, the temperature inside the processing container 10, and the desired coverage area, as the amount of free radicals required to achieve the desired coverage area.

[0129] If the control unit 100 determines that the calculated integral value is above a predetermined value (step S73, "Yes"), it terminates the film formation process (step S74). That is, the control unit 100 proceeds to... Figure 6 In step S64B, the "Do not execute again" branch is executed again, and step S65 is executed again.

[0130] On the other hand, if the control unit 100 determines that the calculated integral value is less than a predetermined value (step S73, "No"), it determines the processing conditions for re-executing the film-forming process (step S75). The determined processing conditions may include the processing time for re-executing steps S631 and S633. For example, if the processing time for the next execution of steps S631 and S633 is set to the same length as the previous one based on the integral value calculated in step S73, and the desired coverage area is exceeded, the control unit 100 sets the processing time for steps S631 and S633 to be shorter. In addition, the determined processing conditions may include a decision on whether to re-execute from step S631 or from step S633. Then, the control unit 100 re-executes the film-forming process under the determined processing conditions (step S76). Then, the control unit 100 proceeds to step S631 or step S633 according to the determined processing conditions.

[0131] Furthermore, the control unit 100 determines the degree of film formation process of the wafer W by the above integral value, so that in the event that the plasma processing device 1 is forcibly terminated during the process, it can determine the processing conditions after the plasma processing device 1 resumes.

[0132] (Example 1 of the monitoring method for the first sensor 108a)

[0133] Furthermore, the first sensor 108a can monitor the state of the plasma at a point, on a surface, or in three dimensions. Next, an example of a monitoring method in the monitoring process will be described.

[0134] In Example 1 of a method for detecting physical quantities in the monitoring process of one implementation, a method using, for example Figure 2 The image shown is obtained when the first sensor 108a is configured on the side of the processing container 10, and the state of the plasma is monitored from the side direction of the processing container 10. The first sensor 108a is, for example, an ultra-high resolution image sensor.

[0135] In Method Example 1, the plasma, along with the passage of time in the obtained image, gradually expands and appears as a whitish object within the processing space. The expansion and intensity of the plasma correspond to the chroma and brightness of the white portion in the image. Therefore, the control unit 100 can obtain a value representing the state of the plasma by analyzing the chroma and brightness of the white portion in the obtained image.

[0136] The first sensor 108a sends the acquired image to the control unit 100. The control unit 100 analyzes the received image and converts the plasma state into a numerical value based on the image's chroma, brightness, etc., and performs calculations. Then, the integral value of the calculated value is compared with a predetermined threshold ( Figure 7 The control unit 100 compares the "prescribed value" with the plasma near the wafer W placed in the processing container 10. Based on the state of the plasma near the wafer W, the control unit 100 calculates the film formation state on the wafer W and can determine the end time of the film formation process.

[0137] (Example 2 of the monitoring method for the first sensor 108a)

[0138] Additionally, the first sensor 108a can be configured to be less than... Figure 2 The processing space near the chip W is monitored from the side of the processing container 10, while the area below is monitored from above the processing container 10. Figure 9A This is a diagram illustrating Example 2 of a method for detecting physical quantities in a monitoring process of one embodiment.

[0139] like Figure 9A As shown, in method example 2, the first sensor 108a monitors the entire W-side of the wafer from above. Figure 9A In the image shown, the portion R1 with a relatively high amount of free radicals is represented as dense, while the portion R2 with a relatively low amount of free radicals is represented as thin. The first sensor 108a acquires this image at predetermined intervals (e.g., every 50 nanoseconds). Furthermore, the first sensor 108a transmits the acquired image to the control unit 100.

[0140] The control unit 100 analyzes the image received from the first sensor 108a and quantifies the intensity of the color corresponding to the amount of free radicals. Figure 9B This indicates that it will be passed Figure 9A The image obtained by method example 2 is shown in the figure. Figure 9B In the example shown, in relation to Figure 9AThe positions corresponding to regions R1 and R2 are displayed with values ​​1, 2, and 3, representing the intensity of the color. The control unit 100 first divides the area containing the surface of the wafer W into multiple regions of uniform area. Furthermore, it analyzes and quantifies the image corresponding to each region. Thus, the control unit 100 can obtain the integral value of the value representing the plasma state for each region of each image.

[0141] like Figure 9A , Figure 9B As shown, when the numerical values ​​representing the state of the plasma in each region, divided into multiple areas within the wafer W plane, are obtained, the control unit 100 can determine the film deposition state based on the position within the wafer W plane. Therefore, the control unit 100 can also use the monitoring processing results to improve the in-plane uniformity of the plasma processing. For example, based on the monitoring processing results, the control unit 100 can adjust the high-frequency power applied to the stage 20 and the gas nozzle in the subsequent processing conditions to values ​​that differ depending on the in-plane position.

[0142] Figure 10 It means based on Figure 9A and Figure 9B Example 2 illustrates the monitoring and processing flow of a typical method. Figure 10 In this example, firstly, at the start of the monitoring process, the first sensor 108a begins monitoring the state of the plasma and sends the acquired information to the control unit 100 for storage (step S1101). At this time, the first sensor 108a monitors the entire surface of the wafer W.

[0143] The control unit 100 parses the received information, such as an image, and calculates values ​​representing the state of the plasma for each of the preset multiple regions (step S1102). Then, based on the calculated values, the control unit 100 calculates the integral value between the film formation processes performed up to this point for each of the multiple regions (step S1103). Furthermore, the control unit 100 calculates the difference between the calculated integral values ​​for the multiple regions (step S1104).

[0144] Next, the control unit 100 determines whether the integral value calculated in step S1103 is above a predetermined value (step S1105). Furthermore, if it is determined to be above the predetermined value (step S1105, "Yes"), the control unit 100 determines whether the difference calculated in step S1104 is below a predetermined value (step S1106). Then, if it is determined to be below the predetermined value (step S1106, "Yes"), the control unit 100 ends the film formation process (step S1107). Then, the control unit 100 proceeds to step S65.

[0145] On the other hand, if the control unit 100 determines that the integral value calculated in step S1103 is less than a predetermined value (step S1105, "No"), it determines the processing conditions for re-performing the film-forming process (step S1108). Then, the film-forming process based on the determined processing conditions is performed (step S1109). In this case, the film-forming process is performed again based on the processing conditions determined in step S1108 and the processing step that is to be re-performed (S631 or S633).

[0146] On the other hand, if the control unit 100 determines that the difference calculated in step S1104 is larger than the specified value (step S1106, "No"), it determines the processing conditions to cancel the difference in order to improve in-plane uniformity (step S1110). Furthermore, the control unit 100 performs the film formation process again based on the determined processing conditions (step S1109). Afterwards, the process proceeds to step S631 or S633. Here, the monitoring process of Method Example 2 ends.

[0147] As described above, according to the plasma processing of this embodiment, the film formation state can be deduced by monitoring the state of the plasma within the processing container 10 without inspecting the pattern on the wafer W itself. Therefore, the plasma processing apparatus 1 of this embodiment can determine the time to end the film formation process with high accuracy and simplicity.

[0148] Next, the first to third detection processes will be described. Here, the detection in the first to third detection processes will be described as the detection performed by the second sensor 108b. However, the detection in the first to third detection processes involves transporting the wafer W to… Figure 1 The observation component OM shown is executed by the observation device OC.

[0149] (First detection and processing)

[0150] The first detection process includes: processing the pattern shape and size detected by the second sensor 108b on the chip W; and processing the control unit 100 to determine the processing conditions for subsequent processing based on the detection results of the second sensor 108b.

[0151] The second sensor 108b detects the shape and size of the pattern on the wafer W using optical methods. The detection method of the second sensor 108b is not particularly limited. The detection result of the second sensor 108b is sent to the control unit 100 and stored in a storage unit such as ROM 110 or RAM 115.

[0152] When receiving the detection result, the control unit 100 compares the detection result with a predetermined pattern size. Then, it calculates the difference between the predetermined pattern size and the detected size. Based on the calculated difference, the control unit 100 adjusts the processing conditions for subsequent processing. Furthermore, the control unit 100 determines the processing conditions to be used in subsequent processing.

[0153] If the pattern formed on the wafer W deviates from the design value when the wafer W is disposed in the processing container 10, and subsequent processing is performed under the processing conditions as designed, the state of the final film is more likely to deviate from the design value. Therefore, in this embodiment, the processing conditions are adjusted based on the difference between the design value and the measured value during the first detection process.

[0154] (Second detection process)

[0155] The second detection process includes: processing the pattern shape and size detected by the second sensor 108b on the chip W; and processing the control unit 100 to determine the processing conditions for subsequent processing based on the detection results of the second sensor 108b.

[0156] The detection process of the second sensor 108b in the second detection process is the same as that in the first detection process. However, when the second detection process is performed, the film deposition process is completed, so the pattern shape formed on the wafer W is different from that in the first detection process. In addition, the predetermined pattern size compared with the detection result in the processing of the control unit 100 is also different from that in the first detection process.

[0157] When receiving the detection result, the control unit 100 compares the detection result with a predetermined pattern size. Then, it calculates the difference between the predetermined pattern size and the detected size. Based on the calculated difference, the control unit 100 determines whether to perform the film deposition process again (step S63). For example, if the calculated difference is above a threshold, the control unit 100 determines that the film deposition process should be performed again. On the other hand, if the calculated difference is less than the threshold, the control unit 100 determines that the film deposition process should not be performed again.

[0158] If it is determined that the film formation process should not be performed again, the control unit 100 then determines the processing conditions for the subsequent etching (step S66). For example, if the film thickness value obtained from the detection result is greater than the set value, the processing conditions are adjusted to enhance the etching effect. Then, the control unit 100 determines the adjusted processing conditions as the etching (step S66) processing conditions.

[0159] Furthermore, when the second sensor 108b used in the second detection process is an infrared sensor or the like, the second sensor 108b can directly measure the thickness of the film formed on the pattern. In this case, the control unit 100 compares the detection result of the second sensor 108b with the predetermined difference in film thickness calculation. Then, based on the calculated difference, the control unit 100 determines whether to perform the film formation process again (step S63). Then, the control unit 100 determines the subsequent processing and processing conditions.

[0160] (Third detection process)

[0161] The third detection process includes: processing the pattern shape and size detected by the second sensor 108b on the chip W; and processing the control unit 100 to determine subsequent processing and processing conditions based on the detection results of the second sensor 108b.

[0162] The detection process for the second sensor 108b in the third detection process is the same as that in the first and second detection processes. However, when the third detection process is performed, the film formation and etching processes are completed, so the pattern shape formed on the wafer W is different from that in the first and second detection processes. In addition, the predetermined pattern size for comparison with the detection results in the control unit 100 process is also different from that in the first and second detection processes.

[0163] When receiving the detection result, the control unit 100 compares the detection result with a predetermined pattern size. Then, it calculates the difference between the predetermined pattern size and the detected size. Based on the calculated difference, the control unit 100 determines whether to perform the film deposition process again (step S63). For example, if the calculated difference is above a threshold and the detected size is smaller than the predetermined pattern size, the control unit 100 determines that the film deposition process should be performed again. On the other hand, if the calculated difference is less than the threshold, the control unit 100 determines that the film deposition process should not be performed again. Furthermore, based on the calculated difference, the control unit 100 determines whether to perform the etching process again (step S66). For example, if the calculated difference is above a threshold and the detected size is larger than the predetermined pattern size, the control unit 100 determines that the etching process should be performed again.

[0164] If it is determined that etching needs to be performed again, the control unit 100 then determines the processing conditions for the film formation process. For example, it determines processing conditions where the difference between the pattern shape obtained from the detection results and the predetermined pattern size is minimized. Then, the control unit 100 performs the film formation process using the determined processing conditions. Figure 6 Step S67, “Film formation is performed again”.

[0165] Furthermore, if it is determined that etching processing needs to be performed again, the control unit 100 then determines the processing conditions for that etching process. For example, it determines processing conditions where the difference between the pattern shape obtained from the detection results and the predetermined pattern size is minimized. Moreover, the control unit 100 performs the etching process using the determined processing conditions. Figure 6 Step S67, "Etching is performed again". If it is determined that neither the film formation process nor the etching process will be performed again (…), then… Figure 6 In step S67, "do not execute again", the control unit 100 terminates the process.

[0166] Furthermore, the first, second, and third detection processes described above can all be implemented using the same detection unit, such as the second sensor 108b or the observation device OC, or a different detection unit can be used in each process. Additionally, the judgment process can be executed by the control unit 100, enabling the first sensor 108a to perform a judgment function and sending the numerical value and timestamp to the control unit 100.

[0167] Figure 11 This diagram illustrates an example of information stored in the storage unit during plasma processing in one embodiment. Figure 11 In the example shown in (A), the size corresponding to the "timestamp" is the result detected in the first, second, and third detection processes. Here, the detection result can be a specific size. Furthermore, it is possible to pre-classify shape anomalies into multiple types and store the types that match the detection results. Figure 11 In step (A), the detection results are categorized and stored as "size A", "size B", etc. Additionally, the monitoring processing results can store values ​​corresponding to multiple timestamps for each step S633 performed once. Furthermore, if the first sensor 108a is an image sensor, multiple images can be stored. Figure 11 In (A), as a monitoring result, the value "V1" of each of the multiple images obtained in step S633, which is quantified and integrated, is stored. Additionally, in Figure 11In (A), the results of the first to third detection processes and the judgment process are stored as "judgment results". For example, the processing condition "X" for subsequent processing is stored in the first detection process. Additionally, for example, the second detection process stores "re-execution" indicating a re-execution of the film deposition process and the processing condition "Y" for re-execution. "Y" also contains information about the specific steps of the execution process. Furthermore, the third detection process stores "no re-execution" indicating that either etching or film deposition will not be re-executed. Since there is no re-execution, "NA" (no compliance) is stored in the processing condition column. Additionally, "re-execution" and "condition X" are stored corresponding to the monitoring process "V1". This indicates that when the film deposition process is re-executed in the judgment process, the processing condition is "X".

[0168] in addition, Figure 11 Example (B) shows a structure where the size and threshold compared to the detection result are stored in the storage unit during each process. For example, in the first detection process, the detection result is compared with "size AA" to determine the processing conditions for subsequent processes. Furthermore, Figure 11 For example, the structure of the information stored in the storage unit for the execution of the first to third detection processes, monitoring processes, and judgment processes is not particularly limited.

[0169] (Modified Example)

[0170] In the above-described embodiments, the detection results of the first detection process (step S62), the monitoring results of the monitoring process (step S64), the detection results of the second detection process (step S65), and the detection results of the third detection process (step S67) are used to adjust the processing conditions of the wafer W that has undergone the processing and to determine whether to repeat each process. However, the above-described detection results and monitoring results can be used not only for the wafer W that has undergone the processing but also for the wafer W' in the next processing. That is, a series of processes (steps S61 to S67) are performed on the wafer W to obtain data related to the shape of the recess before the film deposition process, the state of the plasma during the film deposition process, the state of the film formed by the film deposition process, and the state of the etched film and the shape of the pattern, and the aforementioned correlations are determined. In one example, the correlation between the shape of the recess before the film deposition process, the state of the plasma during the film deposition process, and the state of the film formed by the film deposition process is determined. In another example, the correlation between the state of the plasma during the film deposition process, the state of the film formed during the film deposition process, the state of the etched film, and the shape of the pattern is determined. The aforementioned correlations can be stored as a physical model in the storage unit of the control unit Cnt. Furthermore, based on the physical model, the conditions for the film deposition process (step S63) or etching (step S66) are modified, and the modified conditions are applied to the processing of the substrate W′. In one example, the physical model is constructed by repeatedly performing a loop that includes executing the process, obtaining the correlations, and modifying the conditions. The construction of the physical model can be performed using machine learning. According to this variation, the processing of the wafer W′ can be performed with higher accuracy and in a shorter time than the processing of the wafer W.

[0171] (Effects of the implementation method)

[0172] The plasma processing method of the above embodiment includes steps a), b), c), and d). In step a), a substrate with a recess is provided into a processing container. In step b), plasma is generated within the processing container, and a film is formed on the recess. In step c), the state of the plasma generated in step b) is monitored. In step d), based on the monitored state of the plasma, it is determined whether step b) should be repeated and the processing conditions for re-repeating. Therefore, according to the plasma processing method of the above embodiment, the film formation state can be estimated without investigating the pattern on the substrate itself, and the appropriate processing conditions for re-repeating the film formation process can be determined. Furthermore, according to this plasma processing method, the film formation state can be estimated without removing the substrate from the processing container in order to monitor the state of the plasma during the film formation process. Therefore, according to this plasma processing method, the end time of the film formation process can be determined with high accuracy and ease. Therefore, according to this plasma processing method, the performance of the plasma-based film formation process can be stabilized.

[0173] Furthermore, in the plasma treatment method of the above embodiment, step b) may include steps b-1) and b-2). In step b-1), a first gas is introduced into the treatment container and adsorbed onto the recess. In step b-2), a second gas is introduced into the treatment container to generate plasma of the second gas, which reacts with the components of the first gas adsorbed on the recess to form a film. Then, in step c), the state of the plasma generated in step b-2) is monitored. As described above, the plasma treatment method of the embodiment can be applied to film formation processes, such as ALD, achieved in two stages: adsorption of the first gas and reaction of the second gas.

[0174] Furthermore, in the plasma treatment method of the above embodiment, step b) can be completed before the reaction between the components of the first gas and the second gas on the entire surface of the recess becomes saturated. As described above, the plasma treatment method of the above embodiment can be used to determine the end time of film formation treatment in a subconformal ALD. Therefore, according to the plasma treatment method of the embodiment, the end time of film formation treatment can be calculated with high accuracy, and the film formation treatment can be completed before the film formed in the subconformal ALD reaches saturation.

[0175] Furthermore, in the plasma processing method of the above embodiment, in step c), a physical quantity representing the state of the plasma can be monitored. Then, in step d), if the integral value of this physical quantity obtained through monitoring is less than a predetermined value, it can be determined that step b) should be executed again. Therefore, according to the plasma processing method of the above embodiment, based on the integral value of the physical quantity obtained through monitoring during the film formation process, the state of the film formed from the start of the process to that moment can be calculated with high accuracy. Therefore, according to the embodiment, even if the film formation process is interrupted for any reason, the film formation state at that moment can be calculated based on the monitoring results, and the film formation process can be restarted to make up for the deficiency.

[0176] Furthermore, in the plasma processing method of the above embodiment, in step c), the amount of free radicals in the plasma generated in step b) can be monitored. The amount of free radicals can be calculated, for example, based on electron density, ion density, etc. Moreover, when the temperature inside the processing container and the pattern shape on the substrate to be processed are known, the film formation state can be deduced based on the amount of free radicals. Therefore, according to the above embodiment, the film formation state on the substrate can be easily deduced using physical quantities that can be obtained by means of a light-emitting spectrophotometer or the like.

[0177] Furthermore, in the plasma processing method of the above embodiment, in step c), the state of the plasma in each of the multiple regions set within the substrate mounting surface can be monitored. In step d), if the integral value of the physical quantity representing the state of the plasma in each of the multiple regions is less than a predetermined value, it can be determined that step b) needs to be executed again. Therefore, according to the above embodiment, the film formation state in each region within the substrate surface can be calculated to determine whether the film formation process needs to be executed again.

[0178] Furthermore, in the plasma processing method of the above embodiment, in step c), the state of plasma in each of the multiple regions set within the substrate mounting surface can be monitored. Moreover, in step d), the physical quantities representing the states of plasma in each of the multiple regions are compared; if the difference is greater than a predetermined value, it can be determined that step b) should be executed again. Therefore, according to the above embodiment, the film deposition process can be performed again, making the film deposition state in each region within the substrate surface more uniform. Thus, the plasma processing method of the above embodiment can improve the in-plane uniformity of the film deposition process.

[0179] Furthermore, the plasma processing method of the above embodiment may also include step e) and step f). In step e), after step b), the state of the film on the recess is detected. In step f), based on the detection result of step e), step b) is executed again. Therefore, according to the plasma processing method of the embodiment, not only the state of the plasma is monitored and the state of the film is detected, but it is also possible to determine whether the film formation process needs to be performed again. Therefore, according to the embodiment, the performance of the film formation process using plasma can be stabilized, and high-precision film formation can be achieved.

[0180] Furthermore, the plasma processing method of the above embodiment may also include steps e), f), and g). In step e), after step b), the state of the film on the recess is detected. In step f), processing conditions corresponding to the detection result of step e) are determined. In step g), the base layer of the layer on which the film has been formed on the recess is etched using the processing conditions determined in step f) as a mask. Therefore, according to the embodiment, the subsequent etching processing conditions can be adjusted according to the film formation result, enabling high-precision pattern formation.

[0181] Furthermore, the plasma processing method of the above embodiments may also include step h). In step h), after the execution of step g), the shape of the pattern formed by etching and / or the state of the film on the recess is detected. If the detected shape's consistency with a predetermined shape is below a predetermined value, step b) or step g) is executed again. Therefore, according to the embodiments, it is possible to determine whether to further etch based on the etched shape. Therefore, according to the embodiments, high-precision pattern formation can be achieved.

[0182] Furthermore, the plasma processing method of the above embodiment may also include step i) and step j). In step i), the shape of the recess is detected before step b). In step j), the processing conditions for step b) are determined based on the detection result of step i). Therefore, according to the embodiment, the processing conditions can be determined based on the state of the pattern on the substrate before film deposition and etching. Therefore, according to the embodiment, high-precision pattern formation can be achieved.

[0183] Furthermore, the plasma processing method of the above-described embodiments may also include steps k), l), and m). In step k), based on the shape of the recess of the substrate before step b), the state of the plasma monitored in step c), and the state of the recess of the substrate after step b), the correlation between the shape of the recess before film formation, the state of the plasma, and the state of the film formed in step b) is determined. In step l), the processing conditions in step b) are modified based on the determined correlation. In step m), plasma processing is performed on a substrate different from the substrates for which steps k), l), and m) were performed (the substrate to be processed next). Therefore, according to the embodiments, the film formation conditions can be optimized each time a film formation process is performed on a substrate.

[0184] Furthermore, the plasma processing method of the above embodiments may also include steps n), o), p), and q). In step n), the shape of the pattern formed by etching after step g) and / or the state of the film on the recess is detected. In step o), based on the state of the film detected in step e), the state of the plasma monitored in step c), the shape of the pattern detected in step n), and / or the state of the film on the recess, the correlation between the state of the film before and after step g), the state of the plasma, and the shape of the pattern after step g) is determined. In step p), the processing conditions in step g) are corrected based on the determined correlation. In step q), a substrate different from the substrate to which steps n), o), and p) were performed is etched according to the corrected processing conditions. Therefore, according to the embodiments, the etching conditions can be optimized each time the substrate is etched.

[0185] Furthermore, the plasma processing apparatus of the above embodiment includes one or more processing containers and a control unit. It is configured such that at least one of the one or more processing containers performs etching. Additionally, it is configured such that at least one of the one or more processing containers performs film formation. Alternatively, it can be configured to perform etching and film formation in a single processing container. The processing container has a gas supply unit for supplying processing gas internally. The control unit causes each unit to execute a plasma processing method including steps a), b), c), and d). In step a), a substrate with recesses is provided inside the processing container. In step b), plasma is generated inside the processing container, and a film is formed on the recesses. In step c), the state of the plasma generated in step b) is monitored. In step d), based on the monitored state of the plasma, it is determined whether step b) should be repeated and the processing conditions for re-repeating. Therefore, the plasma processing apparatus according to the embodiment can stabilize the performance of the plasma-based film formation process and achieve high-precision pattern formation.

[0186] Furthermore, the plasma processing method described in the above embodiments is applicable to any substrate processing using plasma, without particular limitation. Additionally, the plasma processing method described in the above embodiments can be used in the manufacturing processes of 3D NAND and DRAM. Furthermore, the plasma processing method described in the above embodiments can be used in the processing of high aspect ratio (AR) organic films, logic-oriented mask processing, etc.

[0187] It should be considered that all the embodiments disclosed in this application are illustrative and not limited thereto. The above embodiments do not depart from the scope and spirit of the appended application and can be omitted, substituted, or modified in various ways.

Claims

1. A plasma processing method, characterized in that, include: Step (a) provides multiple plasma processing devices and observation devices, wherein at least one of the plasma processing devices includes a chamber, a first sensor and a control unit, the chamber includes a stage and a plasma generator opposite to the stage, a substrate with a recess is disposed on the stage in the chamber, the first sensor monitors the state of the plasma generated in the chamber, and the observation device includes a second sensor disposed outside at least one of the plasma processing devices; Step (b) involves using the second sensor to detect the pattern shape on the substrate; Step (c) involves generating plasma in the chamber under first processing conditions determined based on the result of step (b) to form a film that is formed on the upper side of the sidewall of the recess and on the upper surface of the outer side of the recess adjacent to the recess, but not on the lower side of the sidewall of the recess and on the bottom surface of the recess. In step (d), the state of the plasma generated in step (c) is monitored using the first sensor; Step (e) determines the necessity of re-executing step (c) and the second processing conditions when re-executing step (c) based on the state of the plasma monitored in step (d); In step (f), if it is determined in step (e) that step (c) will not be performed again, the second sensor is used to detect the pattern shape of the substrate on which the film is formed; and In step (g), under the third processing conditions determined based on the result of step (f), the substrate layer is etched using the layer formed on the film as a mask. The process (c) includes: Step (c-1): Introduce a first gas into the chamber, causing the first gas to be adsorbed in the recess; Step (c-2) involves purging the chamber. In step (c-3), a second gas is supplied into the chamber, plasma is generated from the second gas, and the components of the second gas react with the components of the first gas adsorbed in the recess to form the membrane; Step (c-4) involves purging the chamber; and Step (c-5) is performed repeatedly with steps (c-1), (c-2), (c-3), and (c-4). Perform at least one of (1) and (2) below, In step (c-1), the first gas is adsorbed only onto a portion of the recess. In step (c-3), the process ends before the reaction of the components of the first gas and the components of the second gas reaches saturation on the entire surface of the recess. In step (c), the film is formed on the sidewall in a manner that the film thickness gradually decreases from the upper side of the sidewall towards the bottom of the recess. In step (d), a process is included to monitor the state of the plasma in each of the multiple regions where the substrate is disposed. In step (e), if the integral value of the physical quantity representing the state of the plasma in each of the plurality of regions, obtained in step (d), is less than a predetermined value, it is determined that step (c) needs to be executed again. The physical quantity includes at least one parameter selected from a parameter group consisting of electron density, ion density, molecular radical density, and atomic, molecular, and ionic mass. The process (e) is performed before, after, or in parallel with the process (c-4). The process (g) and the process (c) are performed in different plasma processing devices. The first processing condition includes at least one of a set of parameters selected from the temperature of the stage on which the substrate is mounted, the pressure of the chamber, the flow rate of the first gas, the supply time of the first gas, and the processing time. The second processing condition includes at least one of the following: processing time when re-executing process (c-1), processing time when re-executing process (c-3), re-execution of process (c) starting from process (c-1), and re-execution of process (c) starting from process (c-3). The third processing condition includes at least one of the following: the supply of etching gas, high-frequency power, and substrate temperature.

2. The plasma treatment method as described in claim 1, characterized in that: A subconformal membrane is formed in the recess.

3. The plasma treatment method as described in claim 1, characterized in that: In the process (c-3), the position of the film formed on the recess is controlled by adjusting at least one parameter selected from a parameter group consisting of the temperature of the stage on which the substrate is arranged, the pressure of the chamber, the flow rate of the second gas, the introduction time of the second gas, the processing time, and the high-frequency power for plasma generation.

4. The plasma treatment method as described in claim 1, characterized in that: In step (d), the amount of free radicals in the plasma generated in step (c) is monitored.

5. The plasma treatment method as described in claim 1, characterized in that: In step (e), physical quantities representing the state of plasma in each region are compared, and if the difference is greater than a predetermined value, a second processing condition is determined to cancel the difference, and step (c) is performed again under the determined second processing condition.

6. The plasma treatment method as described in claim 1, characterized in that: The process (f) includes: Step (f-1), after step (c), detecting the state of the film on the recess; and Step (f-2): Based on the detection results of step (f-1), step (c) is executed again.

7. The plasma treatment method as described in claim 6, characterized in that, Also includes: Step (i) involves detecting the shape of the recess prior to step (c); and Process (j) determines the processing conditions of process (c) based on the detection results of process (i).

8. The plasma treatment method as described in claim 7, characterized in that, include: Step (k) determines the correlation between the shape of the recess detected in step (i), the state of the plasma monitored in step (d), and the pattern shape of the substrate detected in step (f) before film formation, the state of the plasma, and the state of the film formed in step (c). In step (l), based on the aforementioned correlation, the processing conditions of step (c) are modified; and In step (m), under the modified processing conditions of step (l), a film is formed in a recess of a substrate different from the substrate.

9. The plasma treatment method as described in claim 1, characterized in that: The process (f) includes: Step (f-1), after step (c), detecting the state of the film on the recess; and Process (f-2) determines the processing conditions based on the detection results of process (f-1). In step (g), the substrate layer is etched under the processing conditions determined in step (f-2).

10. The plasma processing method as described in claim 9, characterized in that: It also includes step (h), after step (g), detecting the shape of the pattern formed by the etching and / or the state of the film on the recess, and if the degree of consistency between the shape detected in step (h) and the specified shape is below a specified value, then step (c) or step (g) is performed again.

11. The plasma processing method as described in claim 9, characterized in that, Also includes: Step (i) involves detecting the shape of the recess prior to step (c); Step (n) involves detecting the shape of the pattern formed by the etching and / or the state of the film on the recess after step (g); In step (o), based on the state of the membrane detected in step (f), the state of the plasma monitored in step (d), and the shape of the membrane pattern on the recess detected in step (n) and / or the state of the membrane, the correlation between the state of the membrane before and after step (g), the state of the plasma, and the shape of the pattern after step (g) is determined. Process (p) modifies the processing conditions of process (g) based on the aforementioned correlation; and Step (q) involves etching a substrate different from the substrate under the modified processing conditions of step (p).

12. The plasma treatment method as described in claim 1, characterized in that: The first sensor monitors the physical quantities representing the state of the plasma. The second sensor uses optical methods to determine quantities related to the shape of the pattern on the substrate.

13. The plasma processing method as described in claim 12, characterized in that: The physical quantity that represents the state of the plasma is the quantity that can be used to calculate the amount of free radicals in the plasma.

14. The plasma treatment method as described in claim 1, characterized in that: In step (e), the deviation of in-plane uniformity is determined based on the state of the plasma monitored in step (d), and then the second processing conditions when step (c) is executed again are changed based on the determined deviation of in-plane uniformity.

15. A plasma processing method, characterized in that, include: A process for providing a plasma processing apparatus, wherein the plasma processing apparatus has a chamber for housing a substrate having a recess; The process of forming a film on the recess by generating plasma in the chamber, wherein the film is formed on the upper side of the sidewall of the recess and on the upper surface of the outer side of the recess adjacent to the recess, but not on the lower side of the sidewall of the recess and the bottom surface of the recess; A process of using a first sensor to monitor the state of the plasma generated during the process of generating the plasma; The process of using a second sensor to detect the pattern shape on the substrate; The process of determining whether it is necessary to repeat the generation of the plasma; The process of using the second sensor to detect the pattern shape of the substrate on which the film is formed without repeating the plasma generation; and The process of etching the substrate layer using the layer formed on the film as a mask. The process of generating the plasma includes: The process of supplying a first gas into the chamber, such that the first gas is adsorbed only onto a portion of the recess; and The process of supplying a second gas into the chamber, causing the components of the second gas to react with the components of the first gas adsorbed in the recess to form the membrane. In the process of generating the plasma, the generation of the plasma is stopped before the reaction between the components of the first gas and the components of the second gas reaches saturation across the entire surface of the recess. The membrane is formed on the sidewall in such a way that its thickness gradually decreases from the upper side of the sidewall toward the bottom of the recess.

16. The plasma processing method as described in claim 15, characterized in that: The first sensor monitors physical quantities that can be used to calculate the amount of free radicals in the plasma. The second sensor uses optical methods to determine quantities related to the shape of the pattern.

17. The plasma processing method as described in claim 15, characterized in that: Based on the monitoring results, the variation in in-plane uniformity is determined. When the plasma generation is performed again, at least one plasma condition is changed based on the determined change in in-plane homogeneity.

18. The plasma processing method as described in claim 15, characterized in that: Based on the detection using the second sensor, it is determined whether to repeat the plasma generation process or not. Corresponding to the decision to re-execute plasma generation, compared with the immediate execution of plasma generation, at least one processing condition is changed to re-execute plasma generation. Etching is performed in accordance with the decision not to repeat the generation of the plasma.

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