Substrate processing method and substrate processing apparatus

Abstract

The invention provides a substrate processing method and a substrate processing apparatus. The substrate processing method includes a step of providing a substrate and a first step. In the step of providing the substrate, a substrate having a first film and a second film formed on the first film and having a pattern formed thereon is provided. In the first step, a protective film is formed on a side wall of the first film from a product generated by sputtering while the first process gas is converted into plasma to etch the first film while sputtering the second film. The present invention can control the shape of a pattern formed on a substrate by etching.

Description

Technical Field

[0001] The following invention relates to substrate processing methods and substrate processing apparatus. Background Technology

[0002] Plasma etching has been used in the manufacturing process of semiconductor devices to form cylindrical holes or contact holes. In recent years, however, it has become necessary to suppress shape abnormalities such as bowing in the formation of high aspect ratio contact holes (HARC).

[0003] For example, one proposal is for a method of forming a protective film on the inner wall of a recess after the organic film has formed a recess in a substrate in which an organic film, a silicon-containing film, and a pattern mask are stacked sequentially from bottom to top (Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-49141 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] This invention provides a technique for controlling the shape of patterns formed on a substrate by etching.

[0009] Technical solutions for solving technical problems

[0010] One aspect of the substrate processing apparatus and method of the present invention includes a step of providing a substrate and a first step. In the step of providing the substrate, a substrate having a first film and a second film is provided, the second film being formed on the first film and having an opening. In the first step, while ionizing a first processing gas to etch the first film simultaneously with sputtering the second film, a protective film is formed on the sidewalls of the first film by the products generated by the sputtering.

[0011] Invention Effects

[0012] According to the present invention, it is possible to control the shape of the pattern formed on the substrate by etching. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating an example of a substrate processing method in one implementation.

[0014] Figure 2 This is a diagram illustrating an example of a laminated structure processed by a substrate processing method according to one embodiment.

[0015] Figure 3 This is a diagram illustrating the protective film formation process of a substrate processing method according to one embodiment.

[0016] Figure 4 This is a diagram illustrating the etching process of a substrate processing method according to one embodiment.

[0017] Figure 5A This is a diagram illustrating the mask stacking process of a substrate processing method in one embodiment.

[0018] Figure 5B This is a diagram illustrating the mask stacking process of a substrate processing method in one embodiment.

[0019] Figure 6A This is a diagram illustrating the blockage removal process of a substrate processing method according to one embodiment.

[0020] Figure 6B This is a diagram illustrating the blockage removal process of a substrate processing method according to one embodiment.

[0021] Figure 7A It is used for explanation Figure 1 A diagram illustrating an example of the processing flow.

[0022] Figure 7B It is used for explanation Figure 1 Another example of the processing flow is shown in the diagram.

[0023] Figure 8 This is a flowchart illustrating a loop example 1 of a substrate processing method in one implementation.

[0024] Figure 9 This is a flowchart illustrating Example 2 of a substrate processing method in one implementation.

[0025] Figure 10 This is a flowchart illustrating Example 3 of a substrate processing method in one implementation.

[0026] Figure 11 This is a flowchart illustrating a combination of loops in a substrate processing method of one implementation.

[0027] Figure 12 This diagram illustrates the effect that can be obtained through a substrate processing method according to one embodiment.

[0028] Figure 13 This diagram illustrates the conditions used to determine whether to perform processing in a substrate processing method of one embodiment.

[0029] Figure 14This is a diagram illustrating an example of the structure of a substrate processing apparatus for implementing a substrate processing method of one embodiment.

[0030] Figure 15A It is a diagram used to illustrate the stacked structure formed in the manufacturing process of semiconductor devices.

[0031] Figure 15B It is a diagram used to illustrate the pattern of photoresist formed during the manufacturing process of semiconductor devices.

[0032] Figure 15C It is a diagram used to illustrate the pattern of a silicon-containing film formed during the manufacturing process of a semiconductor device.

[0033] Figure 15D It is a diagram used to illustrate the mask pattern formed during the manufacturing process of semiconductor devices.

[0034] Explanation of reference numerals in the attached figures

[0035] 31 Insulating film

[0036] 32 Organic film (etched film)

[0037] 33 Silicon-containing film

[0038] 40 protective film

[0039] 100 substrate processing device

[0040] 102 Processing Room

[0041] 110 mounting platform

[0042] S-layer structure

[0043] Product D

[0044] W chip. Detailed Implementation

[0045] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. Furthermore, these embodiments are not intended to be limiting. Additionally, the embodiments can be appropriately combined without causing contradictions in the processing content.

[0046] (An example of a shape anomaly occurring in the manufacturing process of a semiconductor device)

[0047] Before describing the implementation method, shape anomalies that occur during the manufacturing process of a semiconductor device will be explained. Figure 15A It is a diagram used to illustrate the stacked structure formed in the manufacturing process of semiconductor devices. Figure 15B , Figure 15C , Figure 15DThese are diagrams illustrating the patterns of photoresist, silicon films, and masks formed during the manufacturing process of semiconductor devices.

[0048] First, such as Figure 15A As shown, for example, an organic film 12, a silicon-containing film 13, and a photoresist (PR) 14, which serve as the etchable film, are stacked on an insulating film 11. Figure 15A In the examples, the insulating film 11 is, for example, a SiO2 film. The organic film 12 is, for example, a film with carbon as its main component. The organic film 12 is, for example, an amorphous carbon layer (ACL). Furthermore, the silicon-containing film 13 is an inorganic film containing silicon as its main component. The silicon-containing film 13 is, for example, a SiO2 (silicon dioxide) film, a SiN (silicon nitride) film, a SiON (silicon oxynitride) film, a Poly-Si (polycrystalline silicon) film, or a SiCN (silicon carbonitride) film. The silicon-containing film 13 can be formed using a material that functions as an anti-reflection coating through a photolithography process.

[0049] In formation Figure 15A Following the stacked structure shown, as Figure 15B As shown, a pattern is formed on the photoresist 14 by photolithography. The photoresist 14 can be processed using extreme ultraviolet lithography (EUVL).

[0050] Next, etching is performed by plasma etching gas such as CF4 onto the pattern of the photoresist 14. The silicon-containing film 13 is formed by shaving it away along the pattern of the photoresist 14. Figure 15C The pattern shown is then used. The organic film 12 is etched by plasma etching with O2 gas, H2 gas, N2 gas, or a mixture of H2 and N2 gas, etc., formed on the pattern of the silicon-containing film 13. Figure 15D As shown, the mask pattern formed on the organic film 12 becomes the mask pattern when etching the insulating film 11 under the organic film 12.

[0051] In the etching of the organic film 12, the organic film 12 is etched isotropically using oxygen free radicals, such as... Figure 15D As shown, the longitudinal section of the mask pattern is formed into a transversely widened arc shape 20. If the mask pattern with the arc shape 20 is used to etch the insulating film 11, the shape of the organic film 12 is transferred to the insulating film 11, and the shape of the hole formed in the insulating film 11 deteriorates.

[0052] (Implementation Method)

[0053] Therefore, in the embodiments described below, when etching an organic film using a silicon-containing film as a hard mask, the product (deposit) generated by sputtering the silicon-containing film is used as a protective film for the organic film. In the substrate processing method of the first embodiment, the area where the protective film is formed is, for example, a region with an aspect ratio of at least 5, such as an aspect ratio of 5 to 7, formed in the pattern of the organic film. Furthermore, in the substrate processing method of the first embodiment, the shape of the pattern formed on the substrate by etching is controlled by combining multiple processing steps. In one of the steps, for example, sidewall protection of the pattern is achieved using the sputtering product generated by sputtering.

[0054] In one embodiment of the substrate processing method, for a laminated structure S (refer to) on a substrate in which an insulating film 31, an organic film 32, and a silicon-containing film 33 are sequentially stacked, Figure 2 Patterns for etching the insulating film 31 are formed on the organic film 32. Figure 2 This is a diagram illustrating an example of a laminated structure processed by a substrate processing method according to one embodiment.

[0055] The insulating film 31 is, for example, a SiO2 film. A predetermined pattern is formed on the insulating film 31 by etching from the pattern formed on the organic film 32. The pattern formed on the insulating film 31 becomes a cylindrical hole, contact hole, etc., in a semiconductor device.

[0056] Organic film 32 is, for example, a film with carbon as the main component. Organic film 32 is, for example, an amorphous carbon film. The substrate processing method of this embodiment mainly controls the shape of the pattern formed on organic film 32.

[0057] The silicon-containing film 33 is, for example, a SiO2 film, a SiN film, a SiON film, a Poly-Si film, or a SiCN film. The silicon-containing film 33 can be formed from a material that functions as an anti-reflective film through a photolithography process. The silicon-containing film 33 functions as a hard mask when etching the organic film 32. A predetermined pattern is formed in the silicon-containing film 33. Hereinafter, the pattern formed in the silicon-containing film 33 will be referred to as an "aperture".

[0058] One embodiment of the substrate processing method controls the pattern to be formed on the organic film 32 by combining the process control of (1) to (4) below.

[0059] (1) Protective film formation process

[0060] (2) Etching process

[0061] (3) Mask stacking process

[0062] (4) Blockage removal process

[0063] (Protective film formation process)

[0064] In the protective film formation process, a process gas is plasma-entrained, and a silicon-containing film 33 is sputtered while an organic film 32 is etched. The sputtered product of the silicon-containing film 33 formed by sputtering is deposited on the sidewall of the recess formed in the organic film 32 to form a protective film 40. The process gas used in the protective film formation process is an example of the first process gas. Furthermore, the protective film formation process is an example of the first process.

[0065] Figure 3 This is a diagram illustrating the protective film formation process of a substrate processing method according to one embodiment. For Figure 2 The layered structure S shown undergoes a protective film formation process. In this process, for example, a hydrogen-containing (H2) process gas is plasma-entrained to expose the layered structure S to the plasma. The silicon-containing film 33 is sputtered by the H2-exposed plasma, and sputtering products dispersed by the sputtering deposit on the recessed sidewalls of the organic film 32. Therefore, Figure 3 The stacked structure S includes a protective film 40 deposited on the recessed sidewalls of the silicon-containing film 33 and the organic film 32. In the protective film formation process, the formation of the protective film 40 by sputtering of the silicon-containing film 33 and the etching of the recesses of the organic film 32 are performed simultaneously using a plasma of the process gas. Furthermore, the process gas can be H2 alone, or a mixture of N2 (nitrogen) gas and H2 gas.

[0066] (Etching process)

[0067] Figure 4 This diagram illustrates an etching process in a substrate processing method according to one embodiment. In the etching process, a processing gas is plasma-entrained, and an organic film 32 is etched in the depth direction using a silicon-containing film 33 as a mask. The processing gas used in the etching process is an example of a second processing gas. Furthermore, the etching process is an example of a second process. The etching of the organic film 32 is carried out using a mixture of O2 (oxygen) gas and COS (carbonyl sulfide) gas. Additionally, Cl2 (halogen), HBr (hydrogen bromide), etc., may be added to the processing gas. The processing gas is primarily modulated for etching the organic film 32. By performing the etching process, the silicon-containing film 33, acting as a hard mask, is gradually removed, and recesses corresponding to the openings of the silicon-containing film 33 are formed in the organic film 32, with the recesses gradually deepening.

[0068] (Mask stacking process)

[0069] In the mask stacking process, for example, the thickness of the silicon-containing film 33 is increased by anisotropic deposition. The mask stacking process is an example of the third process. Figure 5A and Figure 5B This is a diagram illustrating the mask stacking process of a substrate processing method in one embodiment. (See diagram for example.) Figure 5AAs shown, after the protective film formation process and the etching process, the thickness of the silicon-containing film 33 gradually decreases. When the aspect ratio of the pattern formed on the organic film 32 is high, the silicon-containing film 33, acting as a hard mask, may disappear before the bottom of the pattern reaches the insulating film 31. Therefore, the mask stacking process performs film deposition from the silicon-containing film 33 using plasma with a third processing gas. The film deposition conditions are set anisotropically. That is, the conditions are set in a manner that allows film deposition primarily to occur on the top of the silicon-containing film 33 without blocking the openings (see reference). Figure 5B ).

[0070] As the third processing gas in the mask stacking process, for example, a mixture of silicon halide gases such as SiCl4 or SiF4, rare gases such as argon (Ar), and O2 can be used. The third processing gas is plasma-entrained, exposing the stacked structure S to the plasma. The film formation method is not particularly limited; chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), and direct current superposition (DCS) can be used. Furthermore, the composition of the film formed in the mask stacking process does not need to be the same as that of the silicon-containing film 33. For example, the film formed in the mask stacking process can be a silicon-containing film with a different composition than the silicon-containing film 33. Additionally, the film formed in the mask stacking process can be any organic film 32 and a material capable of obtaining a high selectivity; it does not necessarily have to be a silicon-containing film.

[0071] (Channel removal process)

[0072] Figure 6A and Figure 6B This diagram illustrates a blockage removal step in a substrate processing method according to one embodiment. In the blockage removal step, a fluorine (F)-containing processing gas is used to remove blockages at the top of the blockage openings and / or patterns generated in any of the protective film formation step, etching step, and mask stacking step. The processing gas used in the blockage removal step is an example of a fourth processing gas. Furthermore, the blockage removal step is an example of a fourth step. Figure 6A As shown, during the pattern formation process on the stacked structure S, there are products formed due to etching adhering to the sidewalls of the openings. Figure 6A (1) of D) and the opening is gradually blocked. In addition, the product generated in the mask stack ( Figure 6A(2) D') also grows in the horizontal direction, and there is a situation where the opening or the upper part of the pattern is gradually blocked. Therefore, in the blockage removal process, the blockage (product) blocking the opening or the pattern is removed by plasma containing fluorine gas. By removing product D or a part of product D', the opening size of the silicon film 33 is restored ( Figure 6B (1) and (2)) enable the processing gas to reach the bottom of the pattern in subsequent processes (e.g., etching processes). In addition, the processing gas used in the blockage removal process can be, for example, a mixture of fluorine-containing gases such as CHF3 and CF4, and rare gases such as N2 or argon (Ar).

[0073] Next, using Figure 1 and Figure 7A The substrate processing method of one embodiment will be described. Figure 1 This is a flowchart illustrating an example of a substrate processing method in one implementation. Figure 7A It is used for explanation Figure 1 A diagram illustrating an example of the processing flow.

[0074] First, prepare the stacked structure S (step S100, Figure 7A (1) Next, it is determined whether the stacked structure S satisfies condition A (step S101). Condition A is, for example, that the thickness of the silicon-containing film 33 on the organic film 32 is above a specified value. Usually, in the first cycle, the stacked structure S satisfies condition A (step S101 is "Yes"), so the mask stacking process is not performed, and the process proceeds to step S103. On the other hand, in the second and subsequent cycles, if it is determined that condition A is not satisfied (step S101 is "No"), the mask stacking process is performed (step S102).

[0075] In step S103, it is determined whether the laminated structure S satisfies condition B. Condition B is, for example, that the aspect ratio of the pattern formed on the organic film 32 reaches a predetermined value α. The predetermined value α is, for example, 5. Furthermore, condition B is, for example, that a protective film 40 (see reference) is formed on the pattern formed on the organic film 32. Figure 3 ).

[0076] If condition B is not met (step S103 is "No"), the protective film formation process is performed (step S104). Figure 7A(2)). For example, if the organic film 32 does not have a pattern, it is determined that condition B is not met. By performing the protective film formation process, while etching the organic film 32, the sputtering product of the silicon-containing film 33 generated by sputtering the silicon-containing film 33 is deposited on the sidewall of the pattern (recess) formed on the organic film 32 to form a protective film 40. When step S104 ends, the process is repeated in step S101. At this time, the thickness of the silicon-containing film 33 is reduced by performing the protective film formation process. If it is determined that condition A is not met (step S101 is "No"), the mask stacking process is performed (step S102).

[0077] On the other hand, if condition B is satisfied (step S103 is "Yes"), proceed to step S105. For example, if the aspect ratio of the pattern formed on the organic film 32 is 6, it is determined that condition B is satisfied. Additionally, for example, if the aspect ratio of the pattern formed on the organic film 32 reaches 5 through multiple protective film forming processes, it is determined that condition B is satisfied. If condition B is satisfied, proceed to step S105.

[0078] Furthermore, in one embodiment, once condition B is met, a protective film may not need to be formed in subsequent processes. In this case, once step S105 is reached, the judgment in step S103 becomes "yes". However, by repeatedly performing step S106, the protective film 40 is removed, and condition B is no longer met (step S103 is "no"), the protective film formation process (step S104) can still be performed.

[0079] In step S105, it is determined whether the stacked structure S satisfies condition C. Condition C is, for example, that the opening size of the silicon film 33 is greater than or equal to a specified size. If it is determined that condition C is not satisfied (step S105 is "No"), the blockage removal process is performed (step S106). When step S106 ends, the process returns to step S101 and repeats. On the other hand, if it is determined that condition C is satisfied (step S105 is "Yes"), the process proceeds to the next step S107.

[0080] In step S107, it is determined whether the stacked structure S satisfies condition D. Condition D is, for example, that the aspect ratio of the pattern formed on the organic film 32 is a predetermined value β different from α. The predetermined value β is, for example, 20~30. If it is determined that condition D is not satisfied (step S107 is "No"), an etching process is performed (step S108, ...). Figure 7A(3)). After step S108 is completed, return to step S101 and repeat the process. At this time, the thickness of the silicon-containing film 33 is reduced by implementing steps S104 and S108, and there is a situation where condition A is not met (step S101 is "No"). In this case, the mask stacking process is performed (step S102, Figure 7A (4)). Furthermore, due to the reduction in the opening size of the silicon-containing film 33 through steps S102 and S108, there is a situation where condition C is not met (step S106 is "No"). In this case, the blockage removal process is performed (step S106, ...). Figure 7A (5)).

[0081] By repeatedly implementing the above process, in step S107, if it is determined that condition D is met (step S107 is "yes"), the process ends.

[0082] Figure 7B It is used for explanation Figure 1 Another example of the processing flow is shown in the diagram. Figure 7B In step (1), a significant portion of the silicon-containing film 33 of the stacked structure S is removed, but not to the extent specified by condition A (step S101 is "Yes"). Furthermore, the aspect ratio of the mask pattern is made less than the specified value β (step S107 is "No"). Therefore, an etching process is performed to etch the mask pattern (step S108). The result of the etching is that the silicon-containing film 33 is removed while the film thickness becomes less than the specified value (step S101 is "No"). Therefore, a mask stacking process is performed to stack the mask ( Figure 7B (2) When the stacked structure S is in a state that satisfies conditions A~D, the processing ends.

[0083] Like this, according to Figure 1 The substrate processing method shown selects the next process step based on the processed state of the stacked structure S. Therefore, by appropriately setting conditions A-D for determining whether to perform each process, the protective film formation process, etching process, mask stacking process, and blockage removal process can be selectively performed, thereby enabling processing suitable for the state of the stacked structure S. Furthermore, the determination of whether conditions A-D are met is implemented by pre-setting the number of times each process must be performed until conditions A-D are met and the applicable processing conditions for each process. For example, the satisfaction of conditions A-D can be determined based on the number of times each process is performed.

[0084] In addition, Figure 1 In the example, after determining whether to perform the protective film formation process, etching process, mask stacking process, and blockage removal process based on conditions A~D, each process is performed. However, the substrate processing method of this embodiment is not limited to this. Figure 1The process is illustrated. For example, the processes to be combined in the protective film formation process, etching process, mask stacking process, and blockage removal process can be preset, as well as the order and number of times the combined processes are performed. For example, a cycle combining the protective film formation process, etching process, mask stacking process, and blockage removal process can be preset, and each cycle can be executed a preset number of times.

[0085] Figure 8 This is a flowchart illustrating a substrate processing method according to one embodiment, Example 1. Example 1 includes a protective film formation process (step S61) and a mask stacking process (step S62). In Example 1, a protective film is first formed on the sidewall of the organic film 32 through the protective film formation process. Then, the mask height of the hard mask (containing silicon film 33) that was reduced due to sputtering in the protective film formation process is restored through the mask stacking process. Furthermore, in... Figures 8-10 In this context, "Pre-C" refers to the previous loop, and "Post-C" refers to the subsequent loop.

[0086] Figure 9 This is a flowchart illustrating a substrate processing method in one embodiment, specifically Example 2. Example 2 includes an etching process (step S71) and a blockage removal process (step S72). In Example 2, a pattern of the organic film 32 is first formed by etching the organic film 32. Then, the blockage removal process removes the deposits formed on the sidewalls of the opening and the sidewalls above the pattern by the etching process.

[0087] Figure 10 This is a flowchart illustrating a substrate processing method in loop example 3 of one embodiment. Loop example 3 includes a mask stacking process (step S81), an etching process (step S82), and a blockage removal process (step S83). Loop example 3 first restores the mask height of the reduced hard mask (containing silicon film 33). Then, the pattern of the organic film 32 is etched in the depth direction. Furthermore, the deposited material on the sidewalls of the opening and the sidewalls above the pattern is removed by etching.

[0088] By combining cycle examples 1 to 3 according to the depth of the pattern formed on the organic film 32, the shape of the pattern can be controlled. For example, cycle example 1 is performed when the organic film 32 has not yet been etched. In this way, the organic film 32 can be etched while suppressing the arcuate shape of the organic film 32, and a protective film can be formed from the sputtered product of the silicon-containing film 33. Furthermore, the top of the silicon-containing film 33 that has disappeared due to sputtering can be strengthened by the mask stacking process. Next, cycle example 2 is performed when the etching of the organic film 32 reaches, for example, a region where arcuate shape is likely to occur. In this way, the silicon-containing film 33 that is prone to arcuate shape is protected directly below by the protective film 40, so the etching can be performed while suppressing the arcuate shape of the organic film 32. Furthermore, the etching product deposited on the sidewalls of the opening and the sidewalls above the pattern can be removed by the blockage removal process. As the etching of the organic film 32 continues, the hard mask is reduced again, so cycle example 3 is performed. Through Example 3, etching is performed on top of a stacked hard mask, and clogging of the opening at the top of the pattern is suppressed.

[0089] In this way, by combining the protective film formation process, etching process, mask stacking process and blockage removal process into a cycle, and combining it with the state of the pattern formed in the stacked structure S, such as the depth of the pattern, the shape of the pattern can be controlled.

[0090] Figure 11 This is a flowchart illustrating a cyclical combination example of a substrate processing method in one implementation. Figure 11 In the example, after loop example 1 is executed a predetermined number of times, such as 5 times, loop example 2 is executed a predetermined number of times, such as 3 times, and loop example 3 is executed a predetermined number of times, such as 4 times. Furthermore, the processing conditions for loop example 3 are changed. For example, loop example 3 is executed 4 times, with changes made between the initial 3 times and the last time.

[0091] First, when processing begins, loop example 1 is executed (step S901). Then, it is determined whether loop example 1 has been executed a predetermined number of times (step S902). If it is determined that the predetermined number of times has not been executed (step S902 is "No"), the process returns to step S901 and loop example 1 is executed repeatedly. On the other hand, if it is determined that the predetermined number of times has been executed (step S902 is "No"), the process proceeds to step S903 and loop example 2 is executed. Then, it is determined whether loop example 2 has been executed a predetermined number of times (step S904). If it is determined that the predetermined number of times has not been executed (step S904 is "No"), the process returns to step S903 and loop example 2 is executed repeatedly. On the other hand, if it is determined that the predetermined number of times has been executed (step S904 is "Yes"), the process proceeds to step S905 and loop example 3 is executed. Here, loop example 3 in step S905 is executed according to processing condition 1. For example, in processing condition 1, the processing time for the mask stacking process is set to 10 seconds. Next, it is determined whether loop example 3 based on processing condition 1 has been executed a predetermined number of times (step S906). If it is determined that the prescribed number of operations has not been performed (step S906 is "No"), the process returns to step S905 and repeats loop example 3. On the other hand, if it is determined that the prescribed number of operations has been performed (step S906 is "Yes"), the process proceeds to step S907 to perform loop example 3. Loop example 3 in step S907 is performed according to processing condition 2. For example, in processing condition 2, the processing time for the mask stacking process is set to 20 seconds. Then, it is determined whether loop example 3 based on processing condition 2 has been performed the prescribed number of times (step S908). If it is determined that the prescribed number of operations has not been performed (step S908 is "No"), the process returns to step S907 and repeats loop example 3. On the other hand, if it is determined that the prescribed number of operations has been performed (step S908 is "Yes"), the process ends.

[0092] In this way, the substrate processing method of the embodiment changes the processes and processing conditions to be performed according to the processing state of the pattern formed on the laminated structure S, for example, according to the etching progress state. In addition, by repeatedly performing a cycle that concentrates multiple processes, the processing can be simplified.

[0093] (Verification results)

[0094] Figure 12 This is a diagram used to illustrate the effect obtained by a substrate processing method according to one embodiment. Figure 12 In the diagram, (A) indicates the state in which a patterned silicon-containing film 33 is formed on the organic film 32 (corresponding to...). Figure 2 In (A), arrows indicate the positions of the insulating film 31, the organic film 32, and the silicon-containing film 33. Furthermore, (B) indicates that no protective film is formed on the laminated structure shown in (A). Figure 3(40) shows the state of the workpiece (comparative example) in which an etching process has been performed. Furthermore, (C) indicates the state of the workpiece (example) in which an organic film pattern has been formed on the laminated structure shown in (A) using the substrate processing method of the above embodiment.

[0095] Each of the objects to be processed is formed comprising an insulating film 31 (the film to be etched), an organic film 32 (the mask) formed on the insulating film 31, and a silicon-containing film 33 (the hard mask) formed on the organic film 32. Then, as... Figure 12 As shown in (A), an opening is formed in the silicon-containing film 33. In (A), some of the organic film 32 is also removed due to etching.

[0096] First, in Comparative Example (B), a mixture of O2 and COS gases was supplied to the chamber at a flow rate ratio of 250 / 50, and the organic film 32 was etched using the silicon-containing film 33 as a hard mask. The chamber temperature was set to 20 mTorr, and the voltages of the upper and lower electrodes were 1400 W and 500 W, respectively. Furthermore, the frequencies of the upper and lower electrodes were set to 27 MHz and 13 MHz, respectively. Additionally, the temperatures (T / W / B) of the upper, sidewall, and lower parts of the chamber were set to 120°C, 100°C, and 10°C, respectively. One etching process was performed, with each etching cycle lasting 300 seconds.

[0097] In embodiment (C), according to Figure 11 The combination shown was implemented using loops 1 to 3. Specifically, loop 1 was implemented 5 times, loop 2 was implemented 3 times, the process of removing the blockage in loop 3 was implemented 3 times with a processing time of 10 seconds, and the process of stacking the mask was implemented once with a processing time of 20 seconds.

[0098] The processing conditions for the protective film formation process, etching process, mask stacking process, and blockage removal process are as follows.

[0099] Protective film formation process:

[0100] Chamber pressure: 20mTorr

[0101] Voltage of upper and lower electrodes: 0W + 900W

[0102] H2 gas flow rate: 250 sccm

[0103] Chamber temperature: T / W / B = 120℃ / 100℃ / 10℃

[0104] Processing time: 120 seconds

[0105] Etching process:

[0106] Chamber pressure: 20mTorr

[0107] Processed gas flow rates: O2 / CO2 = 250 sccm / 50 sccm

[0108] Chamber temperature: T / W / B = 120℃ / 100℃ / 10℃

[0109] Processing time: 100 seconds

[0110] Mask stacking process:

[0111] Chamber pressure: 20mTorr

[0112] Voltage of the upper and lower electrodes: 800W + 0W

[0113] Processed gas flow rates: Ar / O2 / SiCl4 = 500 sccm / 100 sccm / 20 sccm

[0114] Chamber temperature: T / W / B = 120℃ / 100℃ / 10℃

[0115] Blockage removal process:

[0116] Chamber pressure: 30mTorr

[0117] Voltage of the upper and lower electrodes: 300W + 140W

[0118] Processed gas flow rates: CHF3 / CF4 / N2 = 300 sccm / 100 sccm / 150 sccm

[0119] Chamber temperature T / W / B = 120℃ / 100℃ / 10℃

[0120] Processing time: 30 seconds

[0121] Through the processing of comparative examples, we obtained Figure 12 The object being processed is shown in (B). Figure 12 As shown in (B), in the comparative example, an arc shape (the part indicated by the dashed rectangle) was formed in the upper part of the organic film 32. Therefore, the pattern formed on the organic film 32 generally becomes a shape that tapers from top to bottom and towards the front end, with the opening size at the bottom of the pattern slightly narrower (greater than 78 nm). In addition, the longitudinal dimension of the pattern is approximately 2500 nm.

[0122] In contrast, in the embodiment ( Figure 12 In (C), firstly, a protective film 40 is formed by cycling Example 1, and the pattern shown on the left side of (C) is formed on the upper part of the organic film 32 (see reference). Figure 12(See the diagram on the left of (C)). After the aspect ratio becomes greater than 5, repeat Examples 2 and 3 to complete the pattern of organic membrane 32 (refer to...). Figure 12 (The diagram on the right of (C)).

[0123] according to Figure 12 As can be seen from (C), in this embodiment, almost no arcuate pattern is formed in the upper part of the organic film 32, and the lateral expansion is significantly reduced compared to the comparative example (the area indicated by the dashed rectangle). Specifically, the lateral dimension of the arcuate pattern, which was approximately 170 nm in the comparative example, is improved to approximately 105 nm in this embodiment. Furthermore, the pattern formed on the organic film 32 is generally suppressed into a top-down cone shape, and the opening size at the bottom of the pattern is improved compared to the comparative example (approximately 87 nm).

[0124] Furthermore, in the protective film formation process of the above embodiment, hydrogen (H2) gas was used as the processing gas. However, even if it is a processing gas other than hydrogen, it can be used as a processing gas in the protective film formation process if the rate of protective film formation is faster than the rate of bow-shaped formation after etching.

[0125] (An example of an area where a protective film forms)

[0126] The inventors also discussed the conditions used in determining whether to perform the protective film formation process. Figure 13 This diagram illustrates the conditions used in determining whether to perform processing in a substrate processing method according to one embodiment. (See reference...) Figure 13 The conditions for determining whether or not to implement the protective film formation process are explained in section B.

[0127] Figure 13 The six patterns (A) to (F) shown represent an example of the following states.

[0128] (A) State 1 immediately after the pattern is formed on the silicon-containing film 33 of the stacked structure S.

[0129] (B) State 2 after a 30-second protective film formation process was performed on the pattern in State 1.

[0130] (C) State 3 after a 300-second etching process was performed on the pattern in State 2.

[0131] (D) State 4 after a 120-second protective film formation process was performed on the pattern in State 1.

[0132] (E) State 5 after a 300-second etching process was performed on the pattern in State 4.

[0133] (F) State 6 after a 600-second protective film formation process was performed on the pattern of State 1.

[0134] In addition, Figure 13 In the example, the processing conditions for the protective film formation process and the etching process are as follows.

[0135] Protective film formation process:

[0136] Chamber pressure: 20mTorr

[0137] Voltage of upper and lower electrodes: 0W + 900W

[0138] Processed gas flow rate: H2=250

[0139] Chamber temperature: T / W / B = 120℃ / 100℃ / 10℃

[0140] Etching process:

[0141] Chamber pressure: 20mTorr

[0142] Voltage of the upper and lower electrodes: 1400W + 500W

[0143] Processed gas flow rate: O2 / CO2 = 250 sccm / 50 sccm

[0144] Chamber temperature: T / W / B = 120℃ / 100℃ / 10℃

[0145] exist Figure 13 In state 1 shown in (A), an opening is formed in the silicon-containing film 33 of the stacked structure S, which is tapered from top to bottom and gradually becomes thinner at the front end. Figure 13 The example shown has a silicon-containing film 33 with a thickness of approximately 215 nanometers. For such a stacked structure S, after performing a 30-second protective film formation process under the above processing conditions, as shown in (B), the organic film 32 is etched, and a protective film 40 is formed on the sidewall of the opening formed by the etching.

[0146] After a 300-second etching process was performed on the stacked structure S in state 2, a laterally expanding arc shape was formed directly below the opening portion of the organic film 32 in state 2, and the organic film 32 was shaped into the shape shown in (C). In state 3, the opening formed in the organic film 32, at the location where the protective film 40 is formed ( Figure 13 The part represented by A1 in the middle does not produce an arc shape, but an arc shape is produced from directly below the protective film 40.

[0147] When the processing time for the protective film formation process is extended from 30 seconds to 120 seconds, the depth of the opening formed in the organic film 32 increases, and consequently, the area where the protective film 40 is formed expands in the depth direction. Figure 13 (D)). In state 4 shown in (D), the protective film 40 is formed from the top of the organic film 32 to a depth of approximately 130 nanometers (see reference). Figure 13 (The part represented by A2 in the diagram). For the stacked structure S in state 4, after an etching process of 300 seconds under the above processing conditions, as shown in (E), the position where the bow shape is generated shifts downward compared to the example in (C), and the amount of bow shape generated is reduced. In this way, it can be seen that by forming the protective film 40, the position and amount of bow shape generated can be controlled. However, in the example in (E), the result of the etching process is that the silicon-containing film 33, which acts as a mask, is removed, and the opening is blocked by the deposits attached to the top.

[0148] Furthermore, as shown in (F), after the protective film formation process was performed on the laminated structure S in state 1 for 600 seconds under the above processing conditions, the protective film 40 formed on the organic film 32 reached a depth of approximately 380 nanometers in the opening. However, the processing time of the protective film formation process increased, and the amount of silicon-containing film 33 removed also increased. In the example shown in (F), the mask portion of the silicon-containing film 33 was removed in the thickness direction and became deformed and rough in surface condition.

[0149] When the aspect ratio of the pattern formed on the organic film 32 is large, repeatedly performing the protective film formation and etching processes results in the disappearance of the mask pattern of the silicon-containing film 33 and clogging of the openings. On the other hand, the inventors have discovered that, based on the above-mentioned experimental results, when the pattern formed on the organic film 32 is, for example, 100 nanometers in diameter and 2000-3000 nanometers in depth, forming a protective film at the top of the opening can effectively suppress bowing. For example, in the case of an opening with a diameter of 100 nanometers, forming a protective film 40 in a region from the top to approximately 500 nanometers can significantly reduce bowing. Furthermore, forming a protective film 40 in a region with an aspect ratio of approximately 6.7 can significantly reduce bowing. Therefore, the inventors conclude that by forming the protective film 40 to an aspect ratio of 5-7, the pattern shape can be improved.

[0150] (Structure example of a substrate processing device)

[0151] Figure 14 This is a cross-sectional view showing a schematic structure of a substrate processing apparatus 100 according to one embodiment. The substrate processing apparatus 100 includes a processing chamber (cavity) 102 made of metal (e.g., aluminum) and formed in a cylindrical shape (e.g., cylindrical).

[0152] At the bottom of the processing chamber 102, a mounting stage 110 for mounting the wafer W is provided. The mounting stage 110 is formed into a generally cylindrical shape (e.g., cylindrical) from aluminum or the like. Furthermore, although not shown, the mounting stage 110 can be equipped with various functions as needed, such as an electrostatic chuck that uses electrostatic force to attract and hold the wafer W, a heater, and a temperature control mechanism for a coolant flow path. In the case of an etching apparatus, a bias high frequency is applied to the mounting stage 110 to introduce ions into the wafer W.

[0153] At the top of the processing chamber 102, a plate-shaped dielectric 104, made of, for example, quartz glass or ceramic, is disposed opposite to the mounting stage 110. Specifically, the plate-shaped dielectric 104 is formed, for example, in a circular plate shape, and is hermetically mounted to close the opening formed at the top of the processing chamber 102.

[0154] In the processing chamber 102, a gas supply unit 120 is provided for supplying processing gases, etc., used to process the wafer W. A gas inlet 121 is formed in the side wall of the processing chamber 102, and a gas supply source 122 is connected to the gas inlet 121 via a gas supply pipe 123. A flow controller, such as a mass flow controller (MFC) 124 and an on / off valve 126, for controlling the flow rate of the processing gas is provided in the middle of the gas supply pipe 123. Using such a gas supply unit 120, the processing gas from the gas supply source 122 is controlled at a predetermined flow rate by the mass flow controller 124 and supplied into the processing chamber 102 through the gas inlet 121.

[0155] exist Figure 14 For simplicity, the gas supply unit 120 is represented as a single gas pipeline system. However, the gas supply unit 120 is not limited to supplying only one type of process gas; multiple gases can also be supplied as process gases. In this case, multiple gas supply sources can be provided, each consisting of multiple gas pipeline systems, with a mass flow controller installed in each gas pipeline. Furthermore, in... Figure 14 The example shown illustrates a configuration where the gas supply unit 120 is capable of supplying gas from the side wall of the processing chamber 102, but it is not necessarily limited to this. For example, it may also be configured to supply gas from the top of the processing chamber 102. In this case, for example, a gas inlet may be formed in the center of the plate-shaped dielectric 104, and gas may be supplied from this gas inlet.

[0156] As the processing gas supplied to the processing chamber 102 via such a gas supply section 120, halogen gases containing Cl or F can be used, for example, in the etching of oxide films. Specifically, in the case of etching silicon oxide films such as SiO2 films, C can be used. x F y fluorocarbon gases such as CHF3 are used as treatment gases.

[0157] An exhaust section 130, capable of discharging the atmosphere inside the processing chamber 102, is connected to the bottom of the processing chamber 102 via an exhaust pipe 132. The exhaust section 130 includes, for example, a vacuum pump, capable of reducing the pressure inside the processing chamber 102 to a predetermined pressure. A wafer inlet / outlet 134 is formed on the side wall of the processing chamber 102, and a gate valve 136 is provided at the wafer inlet / outlet 134. For example, when a wafer W is fed in, the gate valve 136 is opened, and the wafer W is placed on the loading stage 110 inside the processing chamber 102 using a transport mechanism such as a transport arm (not shown), and the gate valve 136 is closed to process the wafer W.

[0158] At the top of the processing chamber 102, a planar high-frequency antenna 140 and a shielding member 160 covering the high-frequency antenna 140 are provided on the upper side (outer side) of the plate-shaped dielectric 104. In this embodiment, the high-frequency antenna 140 is generally divided into an inner antenna element 142A disposed in the center of the plate-shaped dielectric 104 and an outer antenna element 142B disposed around its outer periphery. Each antenna element 142A and 142B is formed as a spiral coil, for example, made of a conductor such as copper, aluminum, or stainless steel.

[0159] The shielding member 160 of this embodiment includes: a cylindrical inner shielding wall 162A disposed between each antenna element 142A and 142B in a manner that surrounds the inner antenna element 142A; and a cylindrical outer shielding wall 162B disposed in a manner that surrounds the outer antenna element 142B. As a result, the upper surface of the plate-shaped dielectric 104 is divided into a central portion (central region) inside the inner shielding wall 162A and a peripheral edge portion (peripheral edge region) between each shielding wall 162A and 162B.

[0160] On the inner antenna element 142A, a circular inner shielding plate 164A is provided in such a way as to close the opening of the inner shielding wall 162A. On the outer antenna element 142B, a circular outer shielding plate 164B is provided in such a way as to close the opening between each shielding wall 162A, 162B.

[0161] Furthermore, the shape of the shielding member 160 is not limited to a cylindrical shape. The shielding member 160 can be formed into other shapes, such as a square tube, preferably matching the shape of the processing chamber 102. Here, for example, since the processing chamber 102 is formed into a generally cylindrical shape, the shielding member 160 is also formed into a generally cylindrical shape to match it.

[0162] High-frequency power supplies 150A and 150B are connected to each antenna element 142A and 142B, respectively. This allows high frequencies, either the same or different frequencies, to be applied to each antenna element 142A and 142B. For example, when a high-frequency power supply of a specified frequency (e.g., 40MHz) is supplied to the inner antenna element 142A at a specified power from the high-frequency power supply 150A, an induced electric field is formed within the processing chamber 102. This induced electric field excites the processing gas introduced into the processing chamber 102, generating a ring-shaped plasma at the center of the wafer W.

[0163] Furthermore, when a high-frequency signal (e.g., 60 MHz) is supplied to the outer antenna element 142B at a specified power from the high-frequency power supply 150B, an induced electric field is formed within the processing chamber 102. Using this induced electric field, the processing gas introduced into the processing chamber 102 is excited, generating another annular plasma at the peripheral edge of the wafer W.

[0164] These plasmas can be used to perform specified plasma treatments on wafers, such as ashing, etching, and film deposition. The high frequencies output from the high-frequency power supplies 150A and 150B are not limited to the frequencies mentioned above. For example, various frequencies such as 13.56MHz, 27MHz, 40MHz, and 60MHz can be supplied. However, the electrical lengths of the antenna elements 142A and 142B need to be adjusted according to the high frequencies output from the high-frequency power supplies 150A and 150B.

[0165] A control unit (overall control unit) 200 is connected to the substrate processing apparatus 100, through which various parts of the substrate processing apparatus 100 can be controlled. In addition, an operation unit 210 is connected to the control unit 200, which includes a keyboard for the operator to input commands for managing the substrate processing apparatus 100, and a display for visually displaying the operating status of the substrate processing apparatus 100.

[0166] Furthermore, a storage unit 220 is connected to the control unit 200, which stores programs for implementing various processes by the substrate processing device 100 under the control of the control unit 200, as well as scheme data required for executing the programs.

[0167] The storage unit 220 stores, for example, multiple processing schemes for implementing the processing technology of the wafer W, as well as schemes for performing processes such as cleaning within the processing chamber 102. These schemes are schemes that gather multiple parameter values, such as control parameters and setting parameters, for controlling various parts of the substrate processing apparatus 100. For example, the processing schemes include parameter values ​​such as the flow rate ratio of the processing gas, the pressure inside the processing chamber 102, and the frequency and power of the high-frequency applied to each antenna element 142A, 142B.

[0168] Furthermore, these solutions can be stored in a hard disk or semiconductor memory, or they can be set in a designated location in the storage unit 220 while stored in a portable computer-readable storage medium such as a CD-ROM or DVD.

[0169] The control unit 200 reads the desired processing scheme from the storage unit 220 based on instructions from the operation unit 210 to control each unit, thereby implementing the desired processing in the substrate processing apparatus 100. Furthermore, the scheme can be edited through operations from the operation unit 210.

[0170] Furthermore, while an ICP (Inductively Coupled Plasma) device is presented here as an example, the substrate processing apparatus 100 could also be a CCP (Capacitively Coupled Plasma) device. In addition to the high-frequency antenna 140 located at the top of the processing chamber 102, high-frequency electrical power can also be supplied to the lower electrodes constituting the stage 110 to generate plasma.

[0171] (Effects of the implementation method)

[0172] The substrate processing method of the above embodiment includes a substrate provision step and a first step. In the substrate provision step, a substrate having a first film and a second film is provided, wherein the second film is formed on the first film and has openings. In the first step, while ionizing a first processing gas to etch the first film simultaneously with sputtering the second film, a protective film is formed on the sidewall of the first film by the products generated by the sputtering. The substrate processing method of the embodiment allows the formation of the protective film by sputtering the second film and the etching of the first film to be performed in parallel. Therefore, according to the embodiment, the first film (organic film) can be etched while suppressing bow-shaped deformation. Furthermore, according to the substrate processing method of the embodiment, since a protective film can be formed in areas where bow-shaped deformation is prone to occur, bow-shaped deformation can be effectively suppressed. Alternatively, the first step can be performed, for example, until the aspect ratio of the pattern formed on the first film is at least 5.

[0173] Alternatively, the substrate processing method in the above embodiment may also include a second step, in which a second processing gas is plasma-infused and the first film is etched using the second film as a mask.

[0174] Alternatively, the substrate processing method in the above embodiment may further include a third step, in which a third processing gas is plasma-infused to form a silicon-containing film on top of the second film. Therefore, according to the above embodiment, even when the second film, which functions as a mask, is reduced, etching can continue by stacking the second film through the third step. Thus, according to the embodiment, a high aspect ratio pattern can be formed on the first film.

[0175] Alternatively, the substrate processing method of the above embodiment may further include a fourth step, in which a fourth processing gas is plasma-injected to remove blockages in the openings and / or blockages on the upper part of the pattern generated in any of the first, second, and third steps. Therefore, according to the above embodiment, in cases where there is a possibility that the openings or the upper part of the pattern may be blocked by deposits, by appropriately implementing the fourth step, etching can be performed while suppressing opening blockage.

[0176] Alternatively, in the substrate processing method of the above embodiments, multiple cycles consisting of any combination of one or more processes selected from the second, third, and fourth processes can be performed in a predetermined order and number of times. Therefore, according to the above embodiments, processes suitable for the degree of etching can be implemented, and the shape formed by etching can be controlled.

[0177] Alternatively, in the substrate processing method of the above embodiments, a pattern with an aspect ratio of 20 or more may be formed on the first film.

[0178] Alternatively, in the substrate processing method of the above embodiment, a first processing gas containing hydrogen gas can be plasma-plated to sputter a second film as an anti-reflective film.

[0179] Alternatively, the substrate processing method in the above embodiments may also include a step of etching the alternating layers of silicon oxide film and silicon oxynitride film using the first film as a mask.

[0180] Furthermore, the substrate processing apparatus of the above embodiment includes: a storage unit for storing a program for implementing the above substrate processing method; and a control unit for controlling the implementation of the program. Therefore, according to the embodiment, the shape of the pattern formed on the substrate by etching can be controlled.

[0181] The embodiments of the present invention should be understood as illustrative rather than limiting. The above embodiments can be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

Claims

1. A substrate processing method, characterized in that, include: A process of providing a substrate having a first film and a second film, wherein the second film is formed on the first film and has an opening; and In the first process, a first processing gas is plasma-entrained to etch the first film while sputtering the second film, and a protective film is formed on the sidewall of the first film by the products generated by the sputtering.

2. The substrate processing method as described in claim 1, characterized in that: The first process is carried out until the aspect ratio of the pattern formed on the first film is at least 5.

3. The substrate processing method as described in claim 1 or 2, characterized in that: It also includes a second step in which a second processing gas is plasma-entrained and the first film is etched using the second film as a mask.

4. The substrate processing method according to any one of claims 1 to 3, characterized in that: It also includes a third step, which plasma-entrains a third processing gas to form a silicon-containing film on top of the second film.

5. The substrate processing method according to any one of claims 1 to 4, characterized in that: It also includes a fourth step, which plasmas a fourth processing gas to remove blockages that clog the openings and / or form on the pattern of the first membrane.

6. The substrate processing method as described in claim 1 or 2, characterized in that: Multiple cycles consisting of any combination of one or more processes selected from processes 2, 3, and 4 are performed in a prescribed order and number of times, wherein... The second step involves plasma-enhancing the second processing gas and etching the first film using the second film as a mask. The third step involves plasma-injecting a third processing gas to form a silicon-containing film on top of the second film. The fourth step involves plasma-enhancing the fourth processing gas to remove blockages that occurred in any of the first, second, and third steps, clogging the openings and / or forming on the pattern of the first membrane.

7. The substrate processing method as described in claim 6, characterized in that: A pattern with an aspect ratio of 20 or higher is formed on the first film.

8. The substrate processing method according to any one of claims 1 to 7, characterized in that: The first processing gas, which is a hydrogen-containing gas, is plasma-entrained to sputter the second film, which serves as an anti-reflective coating.

9. The substrate processing method according to any one of claims 1 to 8, characterized in that: It also includes a process of etching the alternating layers of silicon oxide film and silicon oxynitride film using the first film as a mask.

10. A substrate processing apparatus, characterized in that, include: A storage unit for a stored program, the program being used to implement the substrate processing method according to any one of claims 1 to 9; and A control unit that controls the implementation of the program.

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