Hard mask removal method and hard mask removal device

Abstract

[Problem] To suppress decreases in throughput when a hard mask is removed. [Solution] According to the present invention, when a hard mask is removed from a wafer W wherein the surface of a pattern formed on an insulating layer and the surface of the hard mask are coated with a CF-based deposit and the hard mask is formed from at least one of tungsten silicide and tungsten silicide nitride, first an oxygen ashing treatment is performed on the wafer, and then, after the temperature of the wafer has been set to at least 90°C, an etching treatment is performed on the wafer with ClF3 gas.

Description

Hard mask removal method and hard mask removal apparatus

[0001] The present disclosure relates to a hard mask removal method and a hard mask removal apparatus.

[0002] Recently, in the manufacturing process of semiconductor devices, a tungsten silicide (WSi) film is sometimes used as a hard mask. ２ ) gas, oxygen (O ２ The metal is removed by etching with plasma generated from hydrogen bromide (HBr) gas (see, for example, Patent Document 1).

[0003] Patent No. 6557588

[0004] The technology according to the present disclosure suppresses a decrease in throughput when removing a hard mask.

[0005] One aspect of the technology disclosed herein is a hard mask removal method for removing a hard mask covering an upper surface of an insulating layer on a substrate on which a pattern has been formed, wherein surfaces of the pattern and the hard mask are covered with fluorocarbon by-products, and the hard mask is formed of at least one of tungsten silicide and tungsten nitride silicide, the method comprising: a first step of removing the by-products by reacting them with oxygen plasma; and a second step of removing the hard mask by setting the temperature of the substrate to 90° C. or higher and reacting the hard mask with a fluorochlorine gas to transform it into various gases.

[0006] According to the technology of the present disclosure, it is possible to suppress a decrease in throughput when removing a hard mask.

[0007] FIG. 1 is a flowchart showing an example of a hard mask removal method according to a first embodiment of the technology disclosed herein. FIG. 2 is a diagram showing an example of steps of the hard mask removal method of FIG. 1 in sequence. FIG. 3 is a diagram showing an example of steps of the hard mask removal method of FIG. 1 in sequence. FIG. 4 is a diagram showing an example of steps of the hard mask removal method of FIG. 1 in sequence. FIG. 5 is a diagram showing an example of steps of the hard mask removal method of FIG. 1 in sequence. FIG. 6 is a flowchart showing a modified example of the hard mask removal method according to the first embodiment. FIG. 7 is a diagram showing an example of steps of the hard mask removal method of FIG. 3 in sequence. FIG. 8 is a diagram showing an example of steps of the hard mask removal method of FIG. 3 in sequence. FIG. 9 is a plan view schematically showing an example of a configuration of a substrate processing apparatus used when performing the hard mask removal method of FIG. 1 or a modified example of the hard mask removal method of FIG. 3. Fig. 7 is a flowchart showing an example of a hard mask removal method according to a second embodiment of the technology disclosed herein. Fig. 8 is a diagram showing in sequence an example of steps of the hard mask removal method of Fig. 6. Fig. 9 is a diagram showing in sequence an example of steps of the hard mask removal method of Fig. 6. Fig. 10 is a diagram showing in sequence an example of steps of the hard mask removal method of Fig. 6. Fig. 11 is a diagram showing in sequence an example of steps of the hard mask removal method of Fig. 6. Fig. 12 is a plan view schematically showing an example of the configuration of a substrate processing apparatus used when performing the hard mask removal method of Fig. 6.

[0008] In the manufacturing process of semiconductor devices, the use of not only WSi films but also tungsten silicide nitride (WSiN) films and mixed films of WSi and WSiN as hard masks is also being considered. Chemical treatment using gases is also being considered for removing WSi and WSiN films. Chemical treatment using such gases involves the use of chlorine fluoride-based gases, such as chlorine trifluoride (ClF ３) gas non-plasma etching process, in which ClF ３ The WSi film or WSiN film is removed by reacting the gas with the WSi or WSiN and transforming it into various gases.

[0009] In a substrate having an insulating layer or hard mask formed on a base such as silicon (Si), a plurality of patterns such as trenches may be formed in the insulating layer. Such patterns are formed by subjecting the substrate to an etching process using a carbon fluoride (CF)-based gas, but CF-based deposits generated during etching of the insulating layer may cover the surface of the hard mask or the surface of the pattern.

[0010] CF-based depots are ClF ３ It is difficult to remove by etching with gas, so the hard mask ClF ３ Prior to the removal by gas etching, the substrate is subjected to oxygen ashing to remove the CF-based deposits. At this time, the oxygen ashing not only removes the CF-based deposits but also oxidizes the exposed surface of the hard mask, so that the surface of the hard mask becomes tungsten oxide (WO ｘ ) membrane. ｘ The film is ClF ３ It is difficult to remove the WO 2 on the surface of the hard mask by etching with gas. ｘ To remove the film, the substrate must be subjected to a hydrogen ashing process, resulting in reduced throughput.

[0011] In contrast, the technology according to the present disclosure can be used to ３ By subjecting the substrate to etching treatment using gas, not only the hard mask but also the WO ｘ The film is removed, and a decrease in throughput when removing the hard mask is suppressed.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the technology according to the present disclosure will be described below with reference to the accompanying drawings. First, a first embodiment of the technology according to the present disclosure will be described.

[0013] 1 is a flowchart showing an example of a hard mask removal method according to the first embodiment, and FIGS. 2A to 2E are views sequentially showing an example of steps of the hard mask removal method of FIG.

[0014] In the hard mask removal method according to the present embodiment, first, a wafer W having an insulating layer with patterns such as trenches and via holes formed therein in advance in another substrate processing apparatus is received. As shown in FIG. 2A , the wafer W has a base 10 made of, for example, silicon (Si) or silicon germanium (SiGe).

[0015] On the base 10, for example, three layers of SiCN films 11a to 11c and two layers of silicon dioxide (SiO ２ The insulating layer 13 is formed of, for example, a SiCN film 11a and a SiO ２ Film 12a, SiCN film 11b, SiO ２ The film 12b and the SiCN film 11c are stacked in this order from the bottom.

[0016] Furthermore, a hard mask 14 made of a mixed film of WSi and WSiN is formed on the insulating layer 13 so as to cover the upper surface of the insulating layer 13. The hard mask 14 may be made of only WSi or only WSiN.

[0017] Furthermore, a plurality of patterns 15, such as trenches exposing the base 10 at the bottom, are formed in the insulating layer 13 and the hard mask 14. These patterns 15 are formed by subjecting the wafer W to an etching process using a carbon fluoride (CF)-based gas in another substrate processing apparatus. CF-based by-products (deposits) 16 generated when the insulating layer 13 is etched cover the surfaces of the hard mask 14 and the patterns 15 ( FIG. 2A ).

[0018] Incidentally, the CF-based deposit 16 covering the surface of the hard mask 14 is ClF ３ Therefore, in this embodiment, the CF-based deposit 16 is removed prior to the removal of the hard mask 14. Specifically, as shown in FIG. ２An oxygen ashing process is performed using oxygen-containing plasma generated from the gas (step S11) (first step). Oxygen-containing radicals contained in the oxygen-containing plasma are highly isotropic and therefore penetrate not only the CF-based deposit 16 covering the surface of the hard mask 14 but also the inside of the pattern 15, and come into contact with the CF-based deposit 16 covering the surface of the pattern 15. The oxygen-containing radicals then oxidize and remove the CF-based deposit 16. Thereafter, the oxygen-containing radicals oxidize the exposed hard mask 14, the SiCN films 11a to 11c exposed inside the pattern 15, and the SiO ２ The hard mask 14 is then brought into contact with the films 12a and 12b and the surfaces of these films are oxidized. As a result, the surface of the hard mask 14 becomes tungsten oxide (WO ｘ ) film 17, and the surface of the pattern 15 is covered with a silicon oxide (SiO ｘ ) covered with a membrane 18 (FIG. 2B).

[0019] By the way, WO ｘ Film and SiO ｘ The oxide film of the film is also normal ClF ３ However, the present applicant has found that the conventional ClF ３ High-temperature ClF etching at a temperature higher than that of the gas ３ WO ｘ On the other hand, the applicant has found that the film can be removed by increasing the temperature. ３ In the gas etching process, SiO ｘ It was also found that the film could not be removed. ３ WO ｘ It was found that the membrane could be selectively removed.

[0020] Therefore, in this embodiment, as shown in FIG. 1, high-temperature ClF ３ The wafer W is subjected to an etching process using a gas (step S12) (second step). ３ When the etching process using gas is performed, the temperature of the wafer W is set to 90° C. or higher, for example, 120° C. At this time, first, the WO 3 covering the upper surface of the hard mask 14 is removed. ｘFilm 17 is removed to expose the top surface of hard mask 14 (FIG. 2C).

[0021] Then, high-temperature ClF ３ As the etching process with the gas continues, the ClF ３ The gas contacts the exposed top surface of the hard mask 14 and removes the hard mask 14. For example, ClF ３ The gas reacts with WSi contained in the hard mask 14 as shown in the following formula (1), to produce tungsten fluoride (VI) (WF ６ ) gas, silicon tetrafluoride (SiF ４ ) gas, chlorine gas, and chlorine fluoride (ClF) gas are produced.

[0022] WSi ２ +5ClF ３ → WF ６ +2SiF ４ + 2Cl ２ +ClF ... (1)

[0023] Also, ClF ３ The gas reacts with WSiN contained in the hard mask 14 as shown in the following formula (2), resulting in WF ６ Gas, SiF ４ Gas, Cl ２ gas, ClF gas and nitrogen (N ２ ) gas is produced.

[0024] 2WSiN+10ClF ３ → 2WF ６ +4SiF ４ + 4Cl ２ + 2ClF + N ２ … (2)

[0025] Thus, ClF ３ In the gas etching process, ClF ３ The hard mask 14 is removed by converting the gas and the hard mask 14 into various gases.

[0026] On the other hand, inside the pattern 15, SiO ｘ The film 18 is a high temperature ClF ３ Since the SiCN films 11a to 11c are not removed by etching with high-temperature ClF ３It is not etched by the etching process using ClF gas for a predetermined time. ３ The etching process using the gas is continued, and when the SiCN film 11c located directly below the hard mask 14 is exposed, the ClF ３ The etching process using the gas is terminated at this predetermined time. ３ The time required for removal by gas etching is set. At this time, some residue 19 generated when removing the hard mask 14 is deposited in a step-like manner on the SiCN film 11c (FIG. 2D).

[0027] 1, the wafer W is subjected to a wet etching process using a chemical solution (step S13) (third step). As a result, the residues 19 and the SiO 2 inside the pattern 15 are removed. ｘ The membrane 18 is removed (FIG. 2E), after which the method ends.

[0028] 3 is a flowchart showing a modification of the hard mask removal method according to the first embodiment. FIGS. 4A to 4G are diagrams sequentially showing an example of the steps of the hard mask removal method shown in FIG. 3. The modification of the hard mask removal method shown in FIG. 3 includes oxygen ashing and high-temperature ClF ３ This method differs from the hard mask removal method shown in Fig. 1 in that the etching process using gas is repeated twice. Note that, in the following, a description of the same process contents and configuration as those in the hard mask removal method shown in Fig. 1 will be omitted, and only the process contents and configuration that are different from those in the hard mask removal method shown in Fig. 1 will be described.

[0029] In the modified hard mask removal method according to the present embodiment, a wafer W having patterns such as trenches and via holes formed in an insulating layer in advance is received from another substrate processing apparatus. In this wafer W, CF-based deposits 16 also cover the surfaces of the hard mask 14 and the patterns 15 (FIG. 4A).

[0030] Next, as shown in FIG. ２A first oxygen ashing process is performed using oxygen-containing plasma generated from the gas (step S31). At this time, oxygen-containing radicals also remove the CF-based deposits 16 covering the surface of the hard mask 14 and the surface of the pattern 15. Furthermore, the oxygen-containing radicals also remove the SiCN films 11a to 11c and SiO 2 exposed on the surface of the hard mask 14 and inside the pattern 15. ２ The surfaces of the films 12a and 12b are oxidized. As a result, the surface of the hard mask 14 becomes WO ｘ The surface of the pattern 15 is covered with a film 17 and is made of SiO ｘ It is covered with a membrane 18 (Fig. 4B).

[0031] Next, as shown in FIG. 3, the temperature of the wafer W is set to 90° C. or higher, for example, 120° C., and the wafer W is subjected to a first high-temperature ClF ３ In this case, the WO 3 film covering the upper surface of the hard mask 14 is first subjected to an etching process using a gas (step S32). ｘ The film 17 is removed to expose the top surface of the hard mask 14 (FIG. 4C). ３ As the etching process using the gas continues, the hard mask 14 with its upper surface exposed is removed by the reactions shown in the above formulas (1) and (2).

[0032] On the other hand, the SiO 2 covering the surfaces of the SiCN films 11a to 11c inside the pattern 15 ｘ The film 18 is a high temperature ClF ３ Since the SiCN films 11a to 11c are not removed by etching with high-temperature ClF ３ The etching process using ClF gas is not performed for a shorter time than in step S12. ３ The gas etching process is then completed. At this point, most of the hard mask 14 is removed, and the upper surface of the SiCN film 11c is partially exposed. However, residues 19 resulting from the removal of the hard mask 14 and unetched portions 14a of the hard mask 14 remain on the SiCN film 11c (FIG. 4D).

[0033] 3, the wafer W is subjected to a second oxygen ashing process (step S33). At this time, oxygen-containing radicals oxidize the partially exposed upper surface of the SiCN film 11c. As a result, not only the surface of the SiCN film 11c inside the pattern 15 but also the upper surface of the SiCN film 11c is oxidized to SiO ｘ The SiCN film 11c is covered with the film 18 (FIG. 4E). That is, the SiCN film 11c is no longer exposed. In the second oxygen ashing process, since it is not necessary to remove the CF-based deposits 16, the execution time of the second oxygen ashing process may be set to be shorter than the execution time of the first oxygen ashing process.

[0034] Next, as shown in FIG. 3, the temperature of the wafer W is again set to 90° C. or higher, for example, 120° C., and the wafer W is subjected to a second high-temperature ClF ３ At this time, the remaining portions 14a and residues 19 of the hard mask 14 are removed, but the SiO 2 film covering the surfaces of the SiCN films 11a to 11c is also removed. ｘ The film 18 is a high temperature ClF ３ As a result, the SiCN films 11a to 11c are not removed by etching with high-temperature ClF ３ It is not etched by the gas etching process (FIG. 4F).

[0035] By the way, the second high-temperature ClF ３ The amount of the unetched portion 14a and the residue 19 removed by the etching process using the gas is determined by the first high-temperature ClF ３ The amount of the hard mask 14 removed by the second high-temperature ClF etching process is less than the amount of the hard mask 14 removed by the second high-temperature ClF etching process. ３ The execution time of the etching process using the first high-temperature ClF ３ It may be set to be shorter than the execution time of the etching process using gas.

[0036] 3, the wafer W is subjected to a wet etching process using a chemical solution (step S35). ｘ The membrane 18 is removed (FIG. 4G), after which the method ends.

[0037] FIG. 5 is a plan view schematically showing an example of the configuration of a substrate processing apparatus used when performing the hard mask removal method of FIG. 1 or a modified example of the hard mask removal method of FIG.

[0038] In FIG. 5, the substrate processing apparatus 20 (hard mask removal apparatus) ３ The system has a plurality of, for example, three gas etching chambers 21 (gas etching processing units) for performing gas etching processing, and a plurality of, for example, three ashing chambers 22 (ashing processing units) for performing oxygen ashing processing or hydrogen ashing processing.

[0039] The gas etching chamber 21 and the ashing chamber 22 are connected to a transfer module 23. The transfer module 23 is connected to a loader module 25 via a load lock module 24. The loader module 25 is provided with a plurality of load ports 26, and each load port 26 is fitted with a container, such as a FOUP (not shown), that accommodates a plurality of wafers W.

[0040] In the substrate processing apparatus 20, a transfer robot (not shown) is built into each of the loader module 25 and the transfer module 23. Each transfer robot transfers wafers W between the gas etching chamber 21, the ashing chamber 22, and each load port 26.

[0041] The loader module 25 is an atmospheric transfer system or a nitrogen transfer system, and its interior is maintained at atmospheric pressure. The transfer module 23 is a vacuum transfer system, and its interior is depressurized to an almost vacuum. The load lock module 24 is configured so that its interior can be switched between atmospheric pressure and an almost vacuum. By switching the internal pressure, the load lock module 24 realizes the transfer of wafers W between the transfer module 23 and the loader module 25 without changing the internal pressure of the transfer module 23 or the loader module 25. The gas etching chamber 21 and the ashing chamber 22 are connected to the transfer module 23 via a gate valve 27.

[0042] 5 or the modified example of the hard mask removal method of FIG. 3, in the substrate processing apparatus 20, the wafer W transferred from the load port 26 is first loaded into the ashing chamber 22. In the ashing chamber 22, the CF-based deposits 16 covering the surfaces of the hard mask 14 and the pattern 15 are removed by oxygen ashing. ｘ The surface of the pattern 15 is covered with a film 17 and the surface of the pattern 15 is covered with SiO ｘ It is covered with a membrane 18 .

[0043] Thereafter, the wafer W is transferred out of the ashing chamber 22 and into the gas etching chamber 21. In the gas etching chamber 21, the wafer W is heated by a stage (not shown) on which the wafer W is placed, and the temperature of the wafer W is set to 90° C. or higher. ３ First, the WO 3 film covering the upper surface of the hard mask 14 is removed by gas etching. ｘ The film 17 is removed, and then the hard mask 14 is removed.

[0044] 1, the wafer W is transferred from the gas etching chamber 21 to the load port 26 and then removed from the substrate processing apparatus 20. The wafer W is then transferred to another substrate processing apparatus, where it is subjected to a wet etching process.

[0045] 3, the wafer W is again transferred from the gas etching chamber 21 to the ashing chamber 22, where it is subjected to oxygen ashing. Thereafter, the wafer W is transferred from the ashing chamber 22 to the gas etching chamber 21, where it is ashed with high-temperature ClF ３ The wafer W is then removed from the gas etching chamber 21 and transferred to another substrate processing apparatus where it is subjected to a wet etching process.

[0046] According to this embodiment, high-temperature ClF ３By the etching process using gas, not only the hard mask 14 but also the WO 2 covering the upper surface of the hard mask 14 is removed. ｘ The film 17 can also be removed. ｘ This eliminates the need to perform hydrogen ashing on the wafer W to remove the film 17. As a result, it is possible to suppress a decrease in throughput when removing the hard mask 14.

[0047] The SiCN film was also ３ In this embodiment, the SiCN films 11a to 11c are made of SiO ｘ The film 18 is then covered with SiO ｘ The film 18 is a high temperature ClF ３ Since the SiCN films 11a to 11c are not removed by etching with ClF ３ As a result, the SiCN films 11a to 11c are prevented from coming into contact with the gas.

[0048] Next, a second embodiment of the technology according to the present disclosure will be described. The second embodiment differs from the first embodiment in that a wiring layer 28 made of a metal, for example, tungsten (W), is formed on the wafer W on which the hard mask 14 to be removed is formed. Note that, in the following, a description of the same processing contents and configuration as those of the first embodiment will be omitted, and only the processing contents and configuration that are different from those of the first embodiment will be described.

[0049] Fig. 6 is a flowchart showing an example of a hard mask removal method according to the second embodiment, and Figs. 7A to 7F are diagrams sequentially showing an example of steps of the hard mask removal method of Fig. 6.

[0050] In the hard mask removal method according to this embodiment, a wafer W having patterns such as trenches and via holes previously formed in an insulating layer is received from another substrate processing apparatus. In this wafer W, a wiring layer 28 made of W is formed between the base 10 and the insulating layer 13. The wiring layer 28 is not covered by the insulating layer 13 or the hard mask 14 at the bottom of the pattern 15, but is covered by a CF-based deposit 16 ( FIG. 7A ).

[0051] 6, in this embodiment, prior to removing the hard mask 14, the wafer W is subjected to oxygen ashing to remove the CF-based deposits 16 (step S61) (first step). The execution time of the oxygen ashing process in step S61 is set shorter than the execution time of the oxygen ashing process in step S11, and is set to approximately the minimum time required to remove the CF-based deposits 16. Specifically, the oxygen ashing process in step S61 removes the SiCN films 11a to 11c and SiO ２ The process ends when the films 12a and 12b are exposed.

[0052] However, the hard mask 14, the SiCN films 11a to 11c, and the SiO ２ The surfaces of the films 12a and 12b are immediately oxidized when they come into contact with oxygen-containing radicals. Therefore, a small amount of oxygen-containing radicals remaining at the end of the oxygen ashing process causes WO 2 to be formed on the surface of the hard mask 14. ｘ The surface of the pattern 15 is covered with a thin film 29 of SiO ｘ Then, a thin film 30 of WO 2 is formed to cover the hard mask 14 (FIG. 7B). ｘ The thin film 29 is ClF ３ It may be difficult to remove by etching with gas.

[0053] Therefore, in this embodiment, WO ｘ High temperature ClF that can remove the film ３ The wafer W is subjected to an etching process using a gas. However, as a result of the CF-based deposit 16 being removed by the oxygen ashing process described above, the wiring layer 28 is exposed at the bottom of the pattern 15. The wiring layer 28 made of W is exposed by ClF ３ ClF used in gas etching processes ３ High temperature ClF ３ During the etching process using the gas on the wafer W, the wiring layer 28 is ３ Exposure to gas must be prevented.

[0054] In response to this, in this embodiment, as shown in FIG.３ Prior to the etching process using gas, an organic deposit 31 is deposited inside the pattern 15 to cover the wiring layer 28 with the organic deposit 31 (step S62) (fourth step). Specifically, the entire surface of the wafer W is covered with the organic deposit 31, and not only the wiring layer 28 inside the pattern 15 but also the hard mask 14 (WO ｘ The thin film 29 is also covered with an organic deposit 31 (FIG. 7C).

[0055] Then, as shown in FIG. ３ Before the etching process using gas, the wafer W is subjected to an ashing process (step S63) (fifth step). The ashing process at this time is performed by oxygen ashing and hydrogen (H ２ However, the ashing process in step S63 is performed after the organic deposit 31 is removed and the WO 2 covering the hard mask 14 is removed. ｘ The process is terminated at a timing when the thin film 29 is exposed but the organic deposit 31 remains inside the pattern 15 (FIG. 7D).

[0056] Next, as shown in FIG. 6, the temperature of the wafer W is set to 90° C. or higher, for example, 120° C., and high-temperature ClF is applied to the wafer W. ３ An etching process using a gas is performed (step S64) (second step). At this time, first, the WO 3 film covering the upper surface of the hard mask 14 is ｘ The thin film 29 is removed to expose the top surface of the hard mask 14, and then a high-temperature ClF ３ As the etching process using the gas continues, the hard mask 14 with its upper surface exposed is removed by the reactions shown in the above formulas (1) and (2).

[0057] On the other hand, the organic deposit 31 inside the pattern 15 is treated with high-temperature ClF ３ It is not removed by etching with ClF ３ The gas does not penetrate into the pattern 15, and the wiring layer 28 is ３ The SiO 2 film covering the surfaces of the SiCN films 11a to 11c inside the pattern 15 is not exposed to gas. ｘ The thin film 30 is also made of high-temperature ClF３ Since the SiCN films 11a to 11c are not removed by etching with high-temperature ClF ３ The SiCN film 11c located directly below the hard mask 14 is not etched by the etching process using ClF ３ The gas etching process is then completed (FIG. 7E).

[0058] 6, the wafer W is again subjected to an ashing process similar to that in step S63 (step S65), and then subjected to a wet etching process using a chemical solution (step S66) (sixth step). As a result, the organic deposits 31 remaining inside the pattern 15 and the SiO 2 inside the pattern 15 are removed. ｘ The thin film 30 is then removed (FIG. 7F). After that, the method is terminated. Note that the organic deposit 31 and the SiO ｘ If both of the thin films 30 can be removed, the ashing process in step S65 may be skipped.

[0059] FIG. 8 is a plan view schematically showing an example of the configuration of a substrate processing apparatus used when performing the hard mask removal method of FIG.

[0060] 8, the substrate processing apparatus 32 (hard mask removal apparatus) has basically the same configuration as the substrate processing apparatus 20, but differs from the substrate processing apparatus 20 in that it has one deposit deposition chamber 33 instead of one gas etching chamber 21. In the deposit deposition chamber 33, an organic deposit 31 is deposited on the wafer W.

[0061] 8 is carried out, in the substrate processing apparatus 32, the wafer W transferred from the load port 26 is first loaded into the ashing chamber 22. In the ashing chamber 22, the CF-based deposits 16 covering the surfaces of the hard mask 14 and the pattern 15 are removed by oxygen ashing. ｘ The surface of the pattern 15 is covered with a thin film 29 of SiO ｘ The thin film 30 is covered with the film.

[0062] Thereafter, the wafer W is transferred out of the ashing chamber 22 and into the deposition chamber 33. In the deposition chamber 33, the entire surface of the wafer W is covered with an organic deposit 31, and the wiring layer 28 inside the pattern 15 is also covered with the organic deposit 31.

[0063] Next, the wafer W is unloaded from the deposition chamber 33 and loaded again into the ashing chamber 22. In the ashing chamber 22, the organic deposit 31 is removed by ashing, and the WO 3 covering the hard mask 14 is removed. ｘ The thin film 29 is exposed. However, the ashing process is terminated so that the organic deposit 31 remains inside the pattern 15. At this time, the ashing process performed in the ashing chamber 22 may be either an oxygen ashing process or a hydrogen ashing process.

[0064] Thereafter, the wafer W is transferred out of the ashing chamber 22 and into the gas etching chamber 21. In the gas etching chamber 21, the temperature of the wafer W is set to 90° C. or higher. ３ First, the WO 3 film covering the upper surface of the hard mask 14 is removed by gas etching. ｘ The thin film 29 is then removed, and then the hard mask 14 is removed.

[0065] Then, the wafer W is unloaded from the gas etching chamber 21 and loaded again into the ashing chamber 22. In the ashing chamber 22, the organic deposits 31 remaining inside the pattern 15 and the SiO 2 remaining inside the pattern 15 are removed by ashing. ｘ In this case, the ashing process carried out in the ashing chamber 22 may be either an oxygen ashing process or a hydrogen ashing process.

[0066] Thereafter, the wafer W is unloaded from the ashing chamber 22, transferred to the load port 26, and then removed from the substrate processing apparatus 32. The wafer W is then transferred to another substrate processing apparatus, where it is subjected to a wet etching process. At this time, the remaining organic deposits 31 and SiOｘ The thin film 30 is completely removed.

[0067] According to this embodiment, high-temperature ClF ３ By the etching process using gas, not only the hard mask 14 but also the WO 2 covering the upper surface of the hard mask 14 is removed. ｘ The thin film 29 of WO ｘ This eliminates the need to perform hydrogen ashing on the wafer W to remove the thin film 29. As a result, it is possible to suppress a decrease in throughput when removing the hard mask 14.

[0068] In this embodiment, WO ｘ Although the hydrogen ashing process is not performed to remove the thin film 29, the hydrogen ashing process may be performed to remove the organic deposit 31, as described above.

[0069] In this embodiment, the wiring layer 28 exposed at the bottom of the pattern 15 is covered with an organic deposit 31, and then etched with high-temperature ClF ３ A gas etching process is carried out, whereby high-temperature ClF ３ During the etching process using the gas, the wiring layer 28 ３ No contact with gas, high temperature ClF ３ This can prevent the wiring layer 28 from being damaged by the etching process using gas.

[0070] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present disclosure.

[0071] For example, the substrate processing apparatus 20 performs ashing and high-temperature ClF ３ The gas etching processes were carried out in the ashing chamber 22 and the gas etching chamber 21, respectively. However, the ashing chamber 22 was not provided with ClF ３ In this case, the ashing chamber 22 may be configured to supply high-temperature ClF ３This allows for both gas-based etching and etching processes, thereby improving throughput.

[0072] In the above-described embodiment, in order to remove the hard mask 14 made of a mixed film of WSi and WSiN, ClF is used as a chlorine fluoride gas. ３ Although a gas is used, other chlorine fluoride gases may also be used.

[0073] This application claims priority based on Japanese Patent Application No. 2024-002494, filed on January 11, 2024, the entire contents of which are incorporated herein by reference.

[0074] W wafer 13 insulating layer 14 hard mask 15 pattern 16 CF-based deposit 17 WO ｘ Film 18 SiO ｘ film

Claims

1. A hard mask removing method for removing a hard mask covering the upper surface of an insulating layer having a pattern formed thereon on a substrate, wherein the surface of the pattern and the surface of the hard mask are covered with fluorocarbon-based by-products, the hard mask is formed of at least one of tungsten silicide and tungsten nitride silicide, a first step of reacting the by-products with oxygen plasma to remove them, and a second step of setting the temperature of the substrate to 90 °C or higher and reacting a chlorine fluoride-based gas with the hard mask to alter it into various gases to remove the hard mask.

2. In the first step, the by-products covering the surface of the hard mask are removed, and a tungsten oxide film is formed on the surface of the hard mask. In the second step, the tungsten oxide film is removed. The hard mask removing method according to claim 1.

3. The hard mask removing method according to claim 1, further comprising a third step of performing a wet etching process on the substrate after the second step.

4. The hard mask removing method according to claim 1, wherein the first step and the second step are repeated twice.

5. The execution time of the second step in the second run is shorter than the execution time of the second step in the first run. The hard mask removing method according to claim 4.

6. A fourth step of covering the hard mask and a wiring layer exposed at the bottom of the pattern after the execution of the first step with an organic-based deposit, and a fifth step of performing an ashing process to remove the organic-based deposit covering the hard mask. The fourth step and the fifth step are performed prior to the second step. The hard mask removing method according to claim 1.

7. The hard mask removing method according to claim 6, further comprising a sixth step of performing an ashing process and a wet etching process on the substrate after the second step.

8. A hard mask removing apparatus for removing a hard mask covering the upper surface of an insulating layer having a pattern formed thereon on a substrate, wherein the surface of the pattern and the surface of the hard mask are covered with a fluorocarbon-based by-product, the hard mask is formed of at least one of tungsten silicide and tungsten nitride silicide, an ashing processing unit for removing the by-product by reacting the by-product with oxygen plasma, and after removing the by-product by the oxygen plasma, setting the temperature of the substrate to 90° C. or higher and then reacting the hard mask with a chlorine fluoride-based gas to alter it into various gases to remove the hard mask, a hard mask removing apparatus comprising a gas etching processing unit.

9. In the ashing processing unit, the by-product covering the surface of the hard mask is removed and a tungsten oxide film is formed on the surface of the hard mask, and in the gas etching processing unit, the tungsten oxide film is removed, the hard mask removing apparatus according to claim 8.

Images