Hard mask removal method and hard mask removal device

Abstract

To suppress reduction in throughput when a hard mask is removed.SOLUTION: When a hard mask is removed from a wafer in which surfaces of a pattern formed on an insulating layer and surfaces of the hard mask are covered with a CF-based deposit and the hard mask is formed of at least one of tungsten silicide and tungsten nitride silicide, first, the wafer is subjected to an oxygen ashing treatment, and then, temperature of the wafer W is set to 90°C or higher, and the wafer is subjected to an etching treatment with ClF3 gas.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, in the manufacturing process of semiconductor devices, a tungsten silicide (WSi) film may be used as a hard mask. Then, the WSi film is removed by etching with plasma generated from chlorine (Cl2) gas, oxygen (O2) gas, or hydrogen bromide (HBr) gas (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

Means for Solving the Problems

[0005] One aspect of the technology according to the present disclosure is a hard mask removal method for removing a hard mask covering an upper surface of an insulating layer on which a pattern is formed on a substrate, wherein a surface of the pattern and a 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 silicide nitride, a first step of reacting the by-product with oxygen plasma to remove it, and a second step of setting the temperature of the substrate to 90°C or higher and then reacting a chlorine fluoride-based gas with the hard mask to transform it into various gases to remove the hard mask.

Effects of the Invention

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

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0008] Incidentally, in the manufacturing process of semiconductor devices, not only WSi films, but also tungsten silicide nitride (WSiN) films and mixed films of WSi and WSiN are being considered for use as hard masks. And for the removal of WSi films and WSiN films, chemical treatment using gases is being considered. Such chemical treatment using gases corresponds to non-plasma etching treatment with chlorine fluoride-based gases, for example, chlorine trifluoride (ClF3) gas. In this etching treatment, the WSi film and WSiN film are removed by reacting the ClF3 gas with WSi or WSiN to transform them into various gases.

[0009] Incidentally, in a substrate on which an insulating layer and a hard mask are 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 treatment using a carbon fluoride (CF)-based gas. However, the CF-based deposits generated when the insulating layer is etched may cover the surface of the hard mask or the surface of the pattern.

[0010] Since it is difficult to remove the CF-based deposits by the etching treatment with ClF3 gas, prior to the removal of the hard mask by the etching treatment with ClF3 gas, an oxygen ashing treatment is performed on the substrate to remove the CF-based deposits. At this time, the oxygen ashing treatment not only removes the CF-based deposits but also oxidizes the exposed surface of the hard mask. Therefore, the surface of the hard mask is covered with a tungsten oxide (WO x ) film. And the WO x film is difficult to remove by the etching treatment with ClF3 gas. Therefore, it is necessary to perform a hydrogen ashing treatment on the substrate to remove the WO x film on the surface of the hard mask, resulting in a reduction in throughput.

[0011] On the other hand, the technology according to the present disclosure suppresses a decrease in throughput when removing the hard mask by subjecting the substrate to an etching treatment with ClF3 gas at a high temperature to remove not only the hard mask but also the WO x film.

[0012] Hereinafter, an embodiment of the technology according to the present disclosure will be described with reference to the drawings. First, a first embodiment of the technology according to the present disclosure will be described.

[0013] FIG. 1 is a flowchart showing a hard mask removal method according to the first embodiment, and FIG. 2 is a process diagram of the hard mask removal method of FIG. 1.

[0014] In the hard mask removal method according to the present embodiment, first, a wafer W having a pattern such as a trench or a via hole formed in an insulating layer in advance by another substrate processing apparatus is received. This wafer W has, for example, a base 10 made of silicon (Si) or silicon germanium (SiGe).

[0015] On the base 10, an insulating layer 13 made of, for example, three layers of SiCN films 11a to 11c and two layers of silicon dioxide (SiO2) films 12a and 12b is formed. In the insulating layer 13, for example, the SiCN film 11a, the SiO2 film 12a, the SiCN film 11b, the SiO2 film 12b, and the SiCN film 11c are laminated in this order from below.

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

[0017] Furthermore, a plurality of patterns 15 such as trenches for 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. And the CF-based by-product (depo) 16 generated when the insulating layer 13 is etched covers the surface of the hard mask 14 and the surface of the pattern 15 (FIG. 2(A)).

[0018] Incidentally, it is difficult to remove the CF-based deposit 16 covering the surface of the hard mask 14 by an etching process using ClF3 gas. Therefore, in the present embodiment, the CF-based deposit 16 is removed prior to the removal of the hard mask 14. Specifically, an oxygen ashing process is performed on the wafer W using oxygen-containing plasma generated from O2 gas (step S11) (first step). Since the oxygen-containing radicals contained in the oxygen-containing plasma are highly isotropic, they penetrate not only the CF-based deposit 16 covering the surface of the hard mask 14 but also into the pattern 15 and come into contact with the CF-based deposit 16 covering the surface of the pattern 15. Then, the oxygen-containing radicals oxidize and remove the CF-based deposit 16. Thereafter, the oxygen-containing radicals come into contact with the exposed hard mask 14 and the SiCN films 11a to 11c and the SiO2 films 12a and 12b exposed inside the pattern 15, and oxidize the surfaces of these films. As a result, the surface of the hard mask 14 is covered with a tungsten oxide (WO x ) film 17, and the surface of the pattern 15 is covered with a silicon oxide (SiO x ) film 18 (Fig. 2(B)).

[0019] Incidentally, it is also difficult to remove oxide films such as the WO x film and the SiO x film by an etching process using normal ClF3 gas. However, the applicant of the present application has found that the WO x film can be removed by an etching process using high-temperature ClF3 gas at a temperature higher than that of the normal etching process using ClF3 gas. On the other hand, the applicant of the present application has also found that the SiO x film cannot be removed by an etching process using ClF3 gas even when the temperature is increased. That is, it has been found that the WO x film can be selectively removed by an etching process using high-temperature ClF3 gas.

[0020] Therefore, in the present embodiment, the wafer W is subjected to an etching process using high-temperature ClF3 gas (step S12) (second step). Specifically, when performing the etching process on the wafer W using ClF3 gas, the temperature of the wafer W is set to 90°C or higher, for example, 120°C. At this time, first, the WO x film 17 covering the upper surface of the hard mask 14 is removed, and the upper surface of the hard mask 14 is exposed (Fig. 2(C)).

[0021] Thereafter, when the etching process using high-temperature ClF3 gas is continued, the ClF3 gas contacts the upper surface of the exposed hard mask 14 and removes the hard mask 14. For example, the ClF3 gas reacts with WSi contained in the hard mask 14 as shown in the following formula (1) to generate tungsten(VI) fluoride (WF6) gas, silicon tetrafluoride (SiF4) gas, chlorine gas, and chlorine fluoride (ClF) gas.

[0022] WSi2 + 5ClF3 → WF6 + 2SiF4 + 2Cl2 + ClF … (1)

[0023] In addition, the ClF3 gas reacts with WSiN contained in the hard mask 14 as shown in the following formula (2) to generate WF6 gas, SiF4 gas, Cl2 gas, ClF gas, and nitrogen (N2) gas.

[0024] 2WSiN + 10ClF3 → 2WF6 + 4SiF4 + 4Cl2 + 2ClF + N2… (2)

[0025] In this way, in the etching process using ClF3 gas, the hard mask 14 is removed by altering the ClF3 gas and the hard mask 14 into various gases.

[0026] On the other hand, inside the pattern 15, SiO covering the surfaces of the SiCN films 11a to 11c xSince the film 18 is not removed by the etching process using high-temperature ClF3 gas, the SiCN films 11a to 11c are not etched by the etching process using high-temperature ClF3 gas. Then, the etching process using ClF3 gas is continued for a predetermined time, and the etching process using ClF3 gas is terminated at the timing when the SiCN film 11c located directly below the hard mask 14 is exposed. As this predetermined time, the time required to remove the hard mask 14 by the etching process using ClF3 gas, which is confirmed by prior experiments or the like, is set. At this time, some residue 19 generated when the hard mask 14 is removed accumulates stepwise on the SiCN film 11c (Fig. 2(D)).

[0027] Next, a wet etching process using a chemical solution is performed on the wafer W (step S13) (the third step). As a result, the residue 19 and the SiO x film 18 inside the pattern 15 are removed (Fig. 2(E)). Then, this method is terminated.

[0028] FIG. 3 is a flowchart showing a modified example of the hard mask removal method according to the first embodiment, and FIG. 4 is a process diagram of the hard mask removal method of FIG. 3. The modified example of the hard mask removal method of FIG. 3 is different from the hard mask removal method of FIG. 1 in that the oxygen ashing process and the etching process using high-temperature ClF3 gas are repeated twice. In the following, the description of the same processing contents and configurations as those of the hard mask removal method of FIG. 1 will be omitted, and only the processing contents and configurations different from those of the hard mask removal method of FIG. 1 will be described.

[0029] Also in the modified example of the hard mask removal method according to the present embodiment, first, a wafer W on which patterns such as trenches and via holes are formed in an insulating layer in advance by another substrate processing apparatus is received. Also in this wafer W, the CF-based deposit 16 covers the surface of the hard mask 14 and the surface of the pattern 15 (Fig. 4(A)).

[0030] Next, a first oxygen ashing treatment using oxygen-containing plasma generated from O2 gas is performed on the wafer W (step S31). Also at this time, the oxygen-containing radicals remove the CF-based deposit 16 covering the surface of the hard mask 14 and the surface of the pattern 15. Further, the oxygen-containing radicals oxidize the surfaces of the exposed hard mask 14 and the SiCN films 11a to 11c and the SiO2 films 12a and 12b exposed inside the pattern 15. As a result, the surface of the hard mask 14 is covered with a WO x film 17, and the surface of the pattern 15 is covered with a SiO x film 18 (Fig. 4(B)).

[0031] Next, the temperature of the wafer W is set to 90°C or higher, for example, 120°C, and a first high-temperature etching treatment using ClF3 gas is performed on the wafer W (step S32). Also at this time, first, the WO x film 17 covering the upper surface of the hard mask 14 is removed, and the upper surface of the hard mask 14 is exposed (Fig. 4(C)). Then, when the etching treatment using high-temperature ClF3 gas is continued, the hard mask 14 with the exposed upper surface is removed by the reactions shown in the above formulas (1) and (2).

[0032] On the other hand, since the SiO x film 18 covering the surfaces of the SiCN films 11a to 11c inside the pattern 15 is not removed by the etching treatment using high-temperature ClF3 gas, the SiCN films 11a to 11c are not etched by the etching treatment using high-temperature ClF3 gas. Then, the etching treatment using ClF3 gas is terminated in a time shorter than that in step S12. At this time, the hard mask 14 is almost removed and a part of the upper surface of the SiCN film 11c is exposed, but the residue 19 generated when the hard mask 14 is removed and the remaining part 14a of the hard mask 14 remain on the SiCN film 11c (Fig. 4(D)).

[0033] Next, the second oxygen ashing process is performed on the wafer W (step S33). At this time, some of the oxygen-containing radicals oxidize the upper surface of the exposed 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 covered with the SiO x film 18 (FIG. 4(E)). That is, the SiCN film 11c is no longer exposed. Note that, since it is not necessary to remove the CF-based deposit 16 in the second oxygen ashing process, the execution time of the second oxygen ashing process may be set shorter than the execution time of the first oxygen ashing process.

[0034] Next, again, the temperature of the wafer W is set to 90° C. or higher, for example, 120° C., and the second high-temperature etching process using ClF3 gas is performed on the wafer W (step S34). At this time, the remaining portion 14a and the residue 19 of the hard mask 14 are removed, but the SiO x film 18 covering the surfaces of the SiCN films 11a to 11c is not removed by the high-temperature etching process using ClF3 gas. As a result, the SiCN films 11a to 11c are not etched by the high-temperature etching process using ClF3 gas (FIG. 4(F)).

[0035] Incidentally, the amount of the remaining portion 14a and the residue 19 removed in the second high-temperature etching process using ClF3 gas is less than the amount of the hard mask 14 removed in the first high-temperature etching process using ClF3 gas. Therefore, in the present embodiment, the execution time of the second high-temperature etching process using ClF3 gas may be set shorter than the execution time of the first high-temperature etching process using ClF3 gas.

[0036] Next, a wet etching process using a chemical solution is performed on the wafer W (step S35). As a result, the SiO x film 18 is removed (FIG. 4(G)). Then, this method is terminated.

[0037] FIG. 5 is a plan view schematically showing the configuration of a substrate processing apparatus used when executing a modification of the hard mask removal method of FIG. 1 or the hard mask removal method of FIG. 3.

[0038] In FIG. 5, a substrate processing apparatus 20 (hard mask removal apparatus) includes a plurality of, for example, three gas etching chambers 21 (gas etching processing units) that execute etching processing using ClF3 gas, and a plurality of, for example, three ashing chambers 22 (ashing processing units) that execute 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. A plurality of load ports 26 are provided in the loader module 25, and a container for accommodating a plurality of wafers W, for example, a FOUP (not shown), is attached to each load port 26.

[0040] In the substrate processing apparatus 20, the loader module 25 and the transfer module 23 each incorporate a transfer robot (not shown). Each transfer robot transfers the wafer 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 the inside is maintained at atmospheric pressure. The transfer module 23 is a vacuum transfer system, and the inside is depressurized to almost vacuum. The load lock module 24 is configured to be able to switch the inside between atmospheric pressure and almost vacuum. The load lock module 24 realizes the transfer of the wafer W between the transfer module 23 and the loader module 25 without changing the internal pressure of the transfer module 23 and the loader module 25 by switching the internal pressure. Note that the gas etching chamber 21 and the ashing chamber 22 are connected to the transfer module 23 via a gate valve 27.

[0042] When executing the hard mask removal method of FIG. 5 or a modified example of the hard mask removal method of FIG. 3, in the substrate processing apparatus 20, the wafer W conveyed from the load port 26 is first carried into the ashing chamber 22. In the ashing chamber 22, the CF-based deposit 16 covering the surface of the hard mask 14 and the surface of the pattern 15 is removed by oxygen ashing treatment, and further, the surface of the hard mask 14 is covered with a WO x film 17, and the surface of the pattern 15 is covered with a SiO x film 18.

[0043] Thereafter, the wafer W is carried out from the ashing chamber 22 and carried into the gas etching chamber 21. In the gas etching chamber 21, the wafer W is heated by a mounting table (not shown) for mounting the wafer W, and the temperature of the wafer W is set to 90° C. or higher. Also, in the gas etching chamber 21, by etching treatment with high-temperature ClF3 gas, first, the WO x film 17 covering the upper surface of the hard mask 14 is removed, and then the hard mask 14 is removed.

[0044] When executing the hard mask removal method of FIG. 1, after the wafer W is conveyed from the gas etching chamber 21 to the load port 26, it is taken out from the substrate processing apparatus 20. Further, the wafer W is conveyed to another substrate processing apparatus, and wet etching treatment is performed on the wafer W in the another substrate processing apparatus.

[0045] When executing the hard mask removal method of FIG. 3, the wafer W is carried into the ashing chamber 22 again from the gas etching chamber 21, and oxygen ashing treatment is performed on the wafer W. Thereafter, the wafer W is carried out from the ashing chamber 22, carried into the gas etching chamber 21, and etching treatment with high-temperature ClF3 gas is performed. Further, the wafer W is taken out from the gas etching chamber 21, conveyed to another substrate processing apparatus, and wet etching treatment is performed.

[0046] According to this embodiment, by the etching process using high-temperature ClF3 gas, not only the hard mask 14 but also the WO x film 17 covering the upper surface of the hard mask 14 can be removed. As a result, it is possible to eliminate the need to perform hydrogen ashing treatment on the wafer W to remove the WO x film 17. As a result, it is possible to suppress a decrease in throughput when removing the hard mask 14.

[0047] Also, the SiCN film may react with ClF3 gas and the SiCN film may be etched and damaged. However, in this embodiment, the SiCN films 11a to 11c are SiO x films 18. And the SiO x film 18 is not removed by the etching process using high-temperature ClF3 gas, so the SiCN films 11a to 11c do not come into contact with ClF3 gas. As a result, it is possible to suppress the SiCN films 11a to 11c from being damaged.

[0048] Next, a second embodiment of the technology according to the present disclosure will be described. The second embodiment is different 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. In the following, the description of the same processing contents and configurations as those of the first embodiment will be omitted, and only the processing contents and configurations different from those of the first embodiment will be described.

[0049] FIG. 6 is a flowchart showing a hard mask removal method according to the second embodiment, and FIG. 7 is a process diagram of the hard mask removal method of FIG. 6.

[0050] Even in the hard mask removal method according to this embodiment, first, a wafer W on which patterns such as trenches and via holes are previously formed in an insulating layer is received by another substrate processing apparatus. In this wafer W, a wiring layer 28 made of W is formed between a base portion 10 and an 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 deposition 16 (FIG. 7(A)).

[0051] Also, in this embodiment, prior to removing the hard mask 14, the wafer W is subjected to an oxygen ashing process to remove the CF-based deposition 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 about the minimum time required to remove the CF-based deposition 16. Specifically, the oxygen ashing process in step S61 ends at the timing when the SiCN films 11a to 11c and the SiO2 films 12a and 12b are exposed inside the hard mask 14 and the pattern 15.

[0052] However, the surfaces of the hard mask 14, the SiCN films 11a to 11c, and the SiO2 films 12a and 12b are immediately oxidized when they come into contact with oxygen-containing radicals. Therefore, a thin film 29 of WO x is formed on the surface of the hard mask 14, and a thin film 30 of SiO x is formed on the surface of the pattern 15 (FIG. 7(B)). Then, the thin film 29 of WO x covering the hard mask 14 is difficult to remove by an etching process using ClF3 gas.

[0053] Therefore, in this embodiment, WO xThe wafer W is subjected to an etching process using high-temperature ClF3 gas that can remove the film. However, as a result of removing the CF-based deposit 16 by the oxygen ashing process described above, the wiring layer 28 is exposed at the bottom of the pattern 15. Since the wiring layer 28 made of W is damaged by the ClF3 gas used in the etching process with ClF3 gas, it is necessary to prevent the wiring layer 28 from coming into contact with the ClF3 gas while the wafer W is being subjected to the etching process with high-temperature ClF3 gas.

[0054] Correspondingly, in the present embodiment, prior to the etching process using high-temperature ClF3 gas, an organic deposit 31 is deposited inside the pattern 15 to cover the wiring layer 28 (step S62) (the 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 thin film 29) is also covered with the organic deposit 31 (FIG. 7(C)).

[0055] Next, before the etching process using high-temperature ClF3 gas, the wafer W is subjected to an ashing process (step S63) (the fifth step). The ashing process at this time may be either an oxygen ashing process or a hydrogen ashing process using hydrogen plasma generated from hydrogen (H2) gas. However, the ashing process in step S63 ends at a timing when the organic deposit 31 is removed and the WO x thin film 29 covering the hard mask 14 is exposed, but the organic deposit 31 remains inside the pattern 15 (FIG. 7(D)).

[0056] Next, the temperature of the wafer W is set to 90°C or higher, for example, 120°C, and the wafer W is subjected to an etching process using high-temperature ClF3 gas (step S64) (the second step). At this time, first, the WO x thin film 29 covering the upper surface of the hard mask 14 is removed, and the upper surface of the hard mask 14 is exposed. Then, when the etching process using high-temperature ClF3 gas is continued, the hard mask 14 with the exposed upper surface is removed by the reactions shown in the above formulas (1) and (2).

[0057] On the one hand, since the organic-based deposit 31 inside the pattern 15 is not removed by the etching process using high-temperature ClF3 gas, the ClF3 gas does not enter the inside of the pattern 15, and the wiring layer 28 is not exposed to the ClF3 gas. Also, since the SiO x thin film 30 covering the surfaces of the SiCN films 11a to 11c inside the pattern 15 is not removed by the etching process using high-temperature ClF3 gas, the SiCN films 11a to 11c are not etched by the etching process using high-temperature ClF3 gas. Then, the etching process using ClF3 gas is terminated at the timing when the SiCN film 11c located directly under the hard mask 14 is exposed (FIG. 7(E)).

[0058] Next, the wafer W is again subjected to an ashing process similar to that in step S63 (step S65), and further, a wet etching process using a chemical solution is performed (step S66) (the sixth step). As a result, the organic-based deposit 31 remaining inside the pattern 15 and the SiO x thin film 30 inside the pattern 15 are removed (FIG. 7(F)). Then, this method is terminated. Note that if both the organic-based deposit 31 and the SiO x thin film 30 can be removed by the wet etching process, the ashing process in step S65 may be skipped.

[0059] FIG. 8 is a plan view schematically showing the configuration of a substrate processing apparatus used when executing the hard mask removal method of FIG. 6.

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

[0061] When executing the hard mask removal method of FIG. 8, in the substrate processing apparatus 32, the wafer W conveyed from the load port 26 is first carried into the ashing chamber 22. In the ashing chamber 22, by oxygen ashing treatment, the CF-based deposit 16 covering the surface of the hard mask 14 and the surface of the pattern 15 is removed, and further, the surface of the hard mask 14 is covered with a thin film 29 of WO x and the surface of the pattern 15 is covered with a thin film 30 of SiO x .

[0062] Thereafter, the wafer W is carried out from the ashing chamber 22 and carried 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 carried out from the deposition chamber 33 and carried into the ashing chamber 22 again. In the ashing chamber 22, by ashing treatment, the organic deposit 31 is removed to expose the thin film 29 of WO x covering the hard mask 14. However, the ashing treatment is terminated so that the organic deposit 31 remains inside the pattern 15. At this time, the ashing treatment executed in the ashing chamber 22 may be either oxygen ashing treatment or hydrogen ashing treatment.

[0064] Thereafter, the wafer W is carried out from the ashing chamber 22 and carried 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. Also, in the gas etching chamber 21, by etching treatment with high-temperature ClF3 gas, first, the thin film 29 of WO x covering the upper surface of the hard mask 14 is removed, and then the hard mask 14 is removed.

[0065] Then, the wafer W is carried out from the gas etching chamber 21 and carried into the ashing chamber 22 again. In the ashing chamber 22, by the ashing process, the organic deposit 31 remaining inside the pattern 15 and the SiO x thin film 30 inside the pattern 15 are removed to some extent. At this time as well, the ashing process executed in the ashing chamber 22 may be either an oxygen ashing process or a hydrogen ashing process.

[0066] After that, the wafer W is carried out from the ashing chamber 22, transported to the load port 26, taken out from the substrate processing apparatus 32, and further transported to another substrate processing apparatus where the wafer W is subjected to wet etching processing. At this time, the remaining organic deposit 31 and the SiO x thin film 30 are completely removed.

[0067] According to this embodiment, by the etching process using high-temperature ClF3 gas, not only the hard mask 14 but also the WO x thin film 29 covering the upper surface of the hard mask 14 can be removed. As a result, it is possible to eliminate the need to perform hydrogen ashing processing on the wafer W to remove the WO x 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, although the hydrogen ashing process for removing the WO x thin film 29 is not executed, as described above, the hydrogen ashing process may be executed to remove the organic deposit 31.

[0069] Also, in this embodiment, after covering the wiring layer 28 exposed at the bottom of the pattern 15 with the organic deposit 31, an etching process using high-temperature ClF3 gas is executed. Thereby, during the execution of the etching process using high-temperature ClF3 gas, the wiring layer 28 does not come into contact with the ClF3 gas, and it is possible to prevent the wiring layer 28 from being damaged by the etching process using high-temperature ClF3 gas.

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

[0071] For example, in the substrate processing apparatus 20, the ashing process and the etching process using high-temperature ClF3 gas were respectively executed in the ashing chamber 22 and the gas etching chamber 21. However, the ashing chamber 22 may be configured to be capable of supplying ClF3 gas therein. In this case, in the ashing chamber 22, both the ashing process and the etching process using high-temperature ClF3 gas can be executed, and the throughput can be improved.

[0072] Further, in the above-described embodiment, in order to remove the hard mask 14 made of a mixed film of WSi and WSiN, ClF3 gas was used as the chlorine fluoride-based gas. However, other chlorine fluoride-based gases may be used.

Description of Reference Numerals

[0073] W wafer 13 Insulating layer 14 Hard mask 15 Pattern 16 CF-based deposition 17 WO x Film 18 SiO x Film

Claims

1. A hard mask removal method for removing a hard mask covering the upper surface of an insulating layer having a pattern formed 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 removal method according to claim 1.

3. The hard mask removal 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 removal method according to claim 1, wherein the first step and the second step are repeatedly executed twice.

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

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 deposition; and a fifth step of performing an ashing process to remove the organic-based deposition covering the hard mask. The hard mask removal method according to claim 1, wherein the fourth step and the fifth step are executed prior to the second step.

7. The hard mask removal 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 removal apparatus for removing a hard mask covering the upper surface of an insulating layer having a pattern formed 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, an ashing processing unit that reacts the by-product with oxygen plasma to remove it, a gas etching processing unit that, after removing the by-product with the oxygen plasma, sets the temperature of the substrate to 90°C or higher and then reacts a chlorine fluoride-based gas with the hard mask to alter it into various gases, thereby removing the hard mask. The hard mask removing apparatus includes the ashing processing unit and the 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. The hard mask removing apparatus according to claim 8, wherein in the gas etching processing unit, the tungsten oxide film is removed.

Images