Etching method and processing system

Abstract

An etching method according to one embodiment of the present disclosure comprises: a step of preparing a substrate that has an etching target, a metal-containing film that has an opening being formed in the surface of said substrate; and a step of etching the etching target. The etching step comprises: (a) a step of etching the etching target using the metal-containing film as a mask; (b) a step of selectively forming, on the surface of the etching target that has been etched, an inhibition layer that inhibits the formation of the metal-containing film; (c) a step of forming the metal-containing film on the surface of the metal-containing film while inhibiting the formation of the metal-containing film on the surface of the etching target by the inhibition layer; and (d) a step of etching the inhibition layer and the etching target using the metal-containing film as a mask.

Description

Etching method and processing system

[0001] The present disclosure relates to etching methods and processing systems.

[0002] Patent Document 1 discloses a technique for forming a trench structure or the like in a low-dielectric-constant insulating layer by transferring a pattern in a hard mask layer to the low-dielectric-constant insulating layer using an etching process.

[0003] Special Publication No. 2015-521799

[0004] The present disclosure provides techniques that allow for the formation of high aspect ratio recess structures.

[0005] An etching method according to one aspect of the present disclosure includes the steps of: preparing a substrate having an etching object on a surface of which a metal-containing film having an opening is formed; and etching the etching object, wherein the etching step includes the steps of: (a) etching the etching object using the metal-containing film as a mask; (b) selectively forming an inhibition layer on the etched surface of the etching object that inhibits formation of the metal-containing film; (c) forming the metal-containing film on the surface of the metal-containing film while using the inhibition layer to inhibit formation of the metal-containing film on the surface of the etching object; and (d) etching the inhibition layer and the etching object using the metal-containing film as a mask.

[0006] According to the present disclosure, recess structures with high aspect ratios can be formed.

[0007] FIG. 1 is a cross-sectional view showing an etching method according to a first example of an embodiment. FIG. 2 is a cross-sectional view showing an etching method according to a second example of an embodiment. FIG. 3 is a cross-sectional view showing an etching method according to a third example of an embodiment. FIG. 4 is a cross-sectional view showing an etching method according to a fourth example of an embodiment. FIG. 5 is a cross-sectional view showing an etching method according to a fifth example of an embodiment. FIG. 6 is a cross-sectional view showing an etching method according to a sixth example of an embodiment. FIG. 7 is a cross-sectional view showing an etching method according to a seventh example of an embodiment. FIG. 8 is a cross-sectional view showing an etching method according to an eighth example of an embodiment. FIG. 9 is a cross-sectional view showing an etching method according to a ninth example of an embodiment. FIG. 10 is a cross-sectional view showing an etching method according to a tenth example of an embodiment. FIG. 11 is a cross-sectional view showing an etching method according to an eleventh example of an embodiment. FIG. 12 is a cross-sectional view showing another example of a substrate. FIG. 13 is a cross-sectional view showing yet another example of a substrate. FIG. 14 is a diagram showing a processing system according to an embodiment.

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding reference numerals are used to designate the same or corresponding members or components, and redundant descriptions will be omitted.

[0009] [Etching Method] (First Example) An etching method according to a first example of the embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing the etching method according to the first example of the embodiment.

[0010] 1A, a substrate 10 is prepared. The substrate 10 includes an object to be etched 11 and a metal-containing film 12.

[0011] The etching target 11 is, for example, a semiconductor substrate. The semiconductor substrate is, for example, a silicon substrate. The etching target 11 may also be an insulating film. The insulating film is, for example, a low dielectric constant (Low-k) film. The insulating film is, for example, a SiO film, a SiN film, a SiOC film, a SiON film, or a SiOCN film. The SiO film refers to a film containing silicon (Si) and oxygen (O). The atomic ratio of Si to O in a SiO film is usually 1:2, but is not limited to 1:2. The SiN film, SiOC film, SiON film, and SiOCN film also similarly refer to the film containing each element and are not limited to a stoichiometric ratio.

[0012] The metal-containing film 12 is provided on the surface of the etching target 11. The metal-containing film 12 has an opening 12a. The opening 12a is provided above a region where a recess structure 13 (described later) is to be formed. The metal-containing film 12 is, for example, a ruthenium (Ru) film or a tungsten (W) film.

[0013] 1B, the etching target 11 is etched using the metal-containing film 12 as a mask. As a result, regions of the etching target 11 that are not covered with the metal-containing film 12 are etched, forming recess structures 13. For example, by supplying plasma generated from an etching gas that has a high etching selectivity ratio of the etching target 11 to the metal-containing film 12 to the substrate 10, the etching target 11 can be selectively removed relative to the metal-containing film 12. When the etching target 11 is etched, the metal-containing film 12 may be etched, resulting in a decrease in thickness of the metal-containing film 12.

[0014] When the etching object 11 is a silicon substrate, the etching gas is, for example, SF ６ When the etching object 11 is a SiO film, a SiN film, a SiOC film, a SiON film, or a SiOCN film, the etching gas is, for example, CF ４ is.

[0015] Next, as shown in FIG. 1C, an inhibition layer 14 that inhibits the formation of the metal-containing film 12 is selectively formed on the surface of the recessed structure 13 relative to the surface of the metal-containing film 12. The inhibition layer 14 is, for example, a self-assembled monolayer (SAM). The inhibition layer 14 may be a silylating agent such as hexamethyldisilazane (HMDS). The inhibition layer 14 may also be a material having a halogen group.

[0016] When forming the inhibitory layer 14 on the surface of the recessed structure 13, a small amount of the inhibitory layer 14 may also adhere to the surface of the metal-containing film 12. In this case, it is preferable to remove the inhibitory layer 14 adhered to the surface of the metal-containing film 12. This prevents the inhibitory layer 14 from inhibiting the formation of the metal-containing film 12 when the metal-containing film 12 is formed on the surface of the metal-containing film 12 in the next step. For example, the inhibitory layer 14 adhered to the surface of the metal-containing film 12 can be removed by supplying plasma generated from a halogen-containing gas to the substrate 10. For example, the inhibitory layer 14 adhered to the surface of the metal-containing film 12 can be removed by supplying an oxidizing gas or plasma generated from the oxidizing gas to the substrate 10.

[0017] Next, as shown in FIG. 1D , a metal-containing film 12 is selectively formed on the metal-containing film 12 while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the recess structure 13. This allows the thickness of the metal-containing film 12 to be increased. The metal-containing film 12 is, for example, a ruthenium film. For example, the metal-containing film 12 can be formed by atomic layer deposition (ALD). Alternatively, the metal-containing film 12 may be formed by chemical vapor deposition (CVD).

[0018] Next, as shown in FIG. 1E, the inhibition layer 14 and the etching object 11 are etched using the metal-containing film 12 as a mask. As a result, regions of the etching object 11 that are not covered with the metal-containing film 12 are etched, and the depth of the recessed structure 13 increases. At this time, the metal-containing film 12 may be etched, resulting in a decrease in the thickness of the metal-containing film 12. The etching shown in FIG. 1E is performed under the same conditions as the etching shown in FIG. 1B, for example. As a result of the above, the recessed structure 13 can be formed on the surface of the etching object 11.

[0019] According to the etching method of the first embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0020] Second Example An etching method according to a second example of the embodiment will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing the etching method according to the second example of the embodiment.

[0021] The etching method of Fig. 2 differs from the etching method of Fig. 1 in that the formation of an inhibition layer 14 on the surface of a recess structure 13 shown in Fig. 2(c), the selective deposition of a metal-containing film 12 shown in Fig. 2(d), and the etching of an etching target 11 shown in Fig. 2(e) are repeated multiple times in this order. The etching method of Fig. 2 is otherwise the same as the etching method of Fig. 1.

[0022] According to the etching method of the second embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0023] According to the etching method of the second embodiment, the formation of the inhibition layer 14 on the surface of the recess structure 13, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are repeated multiple times in this order. In this case, the depth of the recess structure 13 can be increased.

[0024] (Third Example) An etching method according to a third example of the embodiment will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view showing the etching method according to the third example of the embodiment.

[0025] 3 differs from the etching method of Fig. 2 in that the formation of an inhibition layer 14 on the surface of a recess structure 13 shown in Fig. 3(c) and the selective deposition of a metal-containing film 12 shown in Fig. 3(d) are repeated multiple times in this order. The etching method of Fig. 3 is otherwise the same as the etching method of Fig. 2.

[0026] According to the etching method of the third embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0027] According to the etching method of the third embodiment, the formation of the inhibition layer 14 on the surface of the recess structure 13, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are repeated multiple times in this order. In this case, the depth of the recess structure 13 can be increased.

[0028] According to the etching method of the third embodiment, the formation of inhibition layer 14 on the surface of recess structure 13 and the selective deposition of metal-containing film 12 are repeated multiple times in this order. In this case, metal-containing film 12 can be deposited thickly, so that recess structure 13 can be formed deep in a single etching process.

[0029] (Fourth Example) An etching method according to a fourth example of the embodiment will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view showing the etching method according to the fourth example of the embodiment.

[0030] First, as shown in Fig. 4A, a substrate 10 is prepared. The preparation of the substrate 10 shown in Fig. 4A is the same as the preparation of the substrate 10 shown in Fig. 1A, for example.

[0031] Next, as shown in FIG. 4B , an inhibition layer 14 that inhibits the formation of the metal-containing film 12 is selectively formed on the surface of the etching target 11 relative to the surface of the metal-containing film 12. The inhibition layer 14 is, for example, a self-assembled monolayer. The inhibition layer 14 may be a silylating agent such as hexamethyldisilazane. The inhibition layer 14 may also be a material having a halogen group.

[0032] When the inhibitory layer 14 is formed on the surface of the etching target 11, a small amount of the inhibitory layer 14 may also adhere to the surface of the metal-containing film 12. In this case, it is preferable to remove the inhibitory layer 14 adhered to the surface of the metal-containing film 12. This prevents the inhibitory layer 14 from inhibiting the formation of the metal-containing film 12 when the metal-containing film 12 is formed on the surface of the metal-containing film 12 in the next step. The inhibitory layer 14 is removed by the same method as that used to remove the inhibitory layer 14 in FIG. 1C, for example.

[0033] Next, as shown in FIG. 4C , a metal-containing film 12 is selectively formed on the metal-containing film 12 while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching target 11. This allows the thickness of the metal-containing film 12 to be increased. The metal-containing film 12 is, for example, a ruthenium film. For example, the metal-containing film 12 can be formed by atomic layer deposition. Alternatively, for example, the metal-containing film 12 may be formed by chemical vapor deposition.

[0034] When the metal-containing film 12 is formed on the surface of the metal-containing film 12, a small amount of the metal-containing film 12 may also adhere to the surface of the inhibition layer 14. In this case, it is preferable to remove the metal-containing film 12 adhered to the surface of the inhibition layer 14. This prevents the etching of the etching target 11 from being inhibited by the metal-containing film 12 when the etching target 11 is etched in the next step. For example, the metal-containing film 12 adhered to the surface of the inhibition layer 14 can be removed by supplying plasma generated from a halogen-containing gas to the substrate 10. For example, the metal-containing film 12 adhered to the surface of the inhibition layer 14 can be removed by supplying an oxidizing gas or plasma generated from the oxidizing gas to the substrate 10.

[0035] Next, as shown in FIG. 4D , the etching target 11 is etched using the metal-containing film 12 as a mask. As a result, regions of the etching target 11 that are not covered with the metal-containing film 12 are etched, and recess structures 13 are formed. The etching of the etching target 11 shown in FIG. 4D is performed under the same conditions as, for example, the etching of the etching target 11 shown in FIG. 1B . When the etching target 11 is etched, the metal-containing film 12 may be etched, resulting in a decrease in the thickness of the metal-containing film 12.

[0036] Next, as shown in Fig. 4(e), an inhibition layer 14 that inhibits the formation of the metal-containing film 12 is selectively formed on the surface of the recess structure 13 relative to the surface of the metal-containing film 12. The formation of the inhibition layer 14 shown in Fig. 4(e) is performed, for example, under the same conditions as the formation of the inhibition layer 14 shown in Fig. 1(c).

[0037] When the inhibitory layer 14 is formed on the surface of the recess structure 13, a small amount of the inhibitory layer 14 may also adhere to the surface of the metal-containing film 12. In this case, it is preferable to remove the inhibitory layer 14 adhered to the surface of the metal-containing film 12. This prevents the inhibitory layer 14 from inhibiting the formation of the metal-containing film 12 when the metal-containing film 12 is formed on the surface of the metal-containing film 12 in the next step. The inhibitory layer 14 is removed by the same method as that used to remove the inhibitory layer 14 in FIG. 1C, for example.

[0038] Next, as shown in (f) of Fig. 4, a metal-containing film 12 is selectively formed on the metal-containing film 12 while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the recess structure 13. This allows the thickness of the metal-containing film 12 to be increased. The selective formation of the metal-containing film 12 shown in (f) of Fig. 4 is performed under the same conditions as the selective formation of the metal-containing film 12 shown in (d) of Fig. 1, for example.

[0039] Next, as shown in (g) of FIG. 4, the inhibition layer 14 and the etching object 11 are etched using the metal-containing film 12 as a mask. As a result, regions of the etching object 11 that are not covered with the metal-containing film 12 are etched, and the depth of the recessed structure 13 increases. The etching of the inhibition layer 14 and the etching object 11 shown in (g) of FIG. 4 is performed, for example, under the same conditions as the etching of the inhibition layer 14 and the etching object 11 shown in (e) of FIG. 1. At this time, the metal-containing film 12 may be etched, and the thickness of the metal-containing film 12 may decrease. In this manner, the recessed structure 13 can be formed on the surface of the etching object 11.

[0040] According to the etching method of the fourth embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0041] Fifth Example An etching method according to a fifth example of the embodiment will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view showing an etching method according to a fifth example of the embodiment.

[0042] The etching method of Fig. 5 differs from the etching method of Fig. 4 in that the formation of an inhibition layer 14 on the surface of a recess structure 13 shown in (e), the selective deposition of a metal-containing film 12 shown in (f), and the etching of an etching target 11 shown in (g) are repeated multiple times in this order. The etching method of Fig. 5 is otherwise the same as the etching method of Fig. 4.

[0043] According to the etching method of the fifth embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0044] According to the etching method of the fifth embodiment, the formation of the inhibition layer 14 on the surface of the recess structure 13, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are repeated multiple times in this order. In this case, the depth of the recess structure 13 can be increased.

[0045] Sixth Example An etching method according to a sixth example of the embodiment will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view showing an etching method according to a sixth example of the embodiment.

[0046] The etching method of Fig. 6 differs from the etching method of Fig. 5 in that the formation of an inhibition layer 14 on the surface of a recess structure 13 shown in (e) and the selective deposition of a metal-containing film 12 shown in (f) are repeated multiple times in this order. The etching method of Fig. 6 is otherwise the same as the etching method of Fig. 5.

[0047] According to the etching method of the sixth embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0048] According to the etching method of the sixth embodiment, the formation of the inhibition layer 14 on the surface of the recess structure 13, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are repeated multiple times in this order. In this case, the depth of the recess structure 13 can be increased.

[0049] According to the etching method of the sixth embodiment, the formation of inhibition layer 14 on the surface of recess structure 13 and the selective deposition of metal-containing film 12 are repeated multiple times in this order. In this case, metal-containing film 12 can be deposited thickly, so that recess structure 13 can be formed deep in a single etching process.

[0050] Seventh Example An etching method according to a seventh example of the embodiment will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing an etching method according to a seventh example of the embodiment.

[0051] The etching method of Fig. 7 differs from the etching method of Fig. 4 in that the formation of an inhibition layer 14 on the surface of an etching target 11 shown in Fig. 7(b) and the selective deposition of a metal-containing film 12 shown in Fig. 7(c) are repeated multiple times in this order. The etching method of Fig. 7 is otherwise the same as the etching method of Fig. 4.

[0052] According to the etching method of the seventh embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0053] According to the etching method of the seventh embodiment, the formation of the inhibition layer 14 on the surface of the etching target 11 and the selective deposition of the metal-containing film 12 are repeated multiple times in this order. In this case, the metal-containing film 12 can be deposited thickly, and therefore the depth of the recessed structure 13 that can be formed by a single etching process can be increased.

[0054] Eighth Example An etching method according to an eighth example of the embodiment will be described with reference to Fig. 8. Fig. 8 is a cross-sectional view showing an etching method according to an eighth example of the embodiment.

[0055] The etching method of Fig. 8 differs from the etching method of Fig. 7 in that the formation of an inhibition layer 14 on the surface of a recess structure 13 shown in (e), the selective deposition of a metal-containing film 12 shown in (f), and the etching of an etching target 11 shown in (g) are repeated multiple times in this order. The etching method of Fig. 8 is otherwise the same as the etching method of Fig. 7.

[0056] According to the etching method of the eighth embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0057] According to the etching method of the eighth embodiment, the formation of the inhibition layer 14 on the surface of the etching target 11 and the selective deposition of the metal-containing film 12 are repeated multiple times in this order. In this case, the metal-containing film 12 can be deposited thickly, and therefore the depth of the recess structure 13 that can be formed by a single etching process can be increased.

[0058] According to the etching method of the eighth embodiment, the formation of the inhibition layer 14 on the surface of the recess structure 13, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are repeated multiple times in this order. In this case, the depth of the recess structure 13 can be increased.

[0059] Ninth Example An etching method according to a ninth example of the embodiment will be described with reference to Fig. 9. Fig. 9 is a cross-sectional view showing an etching method according to a ninth example of the embodiment.

[0060] 9 differs from the etching method of FIG. 8 in that the formation of an inhibition layer 14 on the surface of a recess structure 13 shown in (e) and the selective deposition of a metal-containing film 12 shown in (f) are repeated multiple times in this order. The etching method of FIG. 9 is otherwise the same as the etching method of FIG. 8.

[0061] According to the etching method of the ninth embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0062] According to the etching method of the ninth embodiment, the formation of the inhibition layer 14 on the surface of the recess structure 13, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are repeated multiple times in this order. In this case, the depth of the recess structure 13 can be increased.

[0063] According to the etching method of the ninth embodiment, the formation of inhibition layer 14 on the surface of recess structure 13 and the selective deposition of metal-containing film 12 are repeated multiple times in this order. In this case, metal-containing film 12 can be deposited thickly, so that recess structure 13 can be formed to a greater depth in a single etching process.

[0064] (Tenth Example) An etching method according to a tenth example of the embodiment will be described with reference to Fig. 10. Fig. 10 is a cross-sectional view showing an etching method according to a tenth example of the embodiment.

[0065] First, as shown in Fig. 10A, a substrate 10 is prepared. The preparation of the substrate 10 shown in Fig. 10A is the same as the preparation of the substrate 10 shown in Fig. 1A, for example.

[0066] 10(b), an inhibition layer 14 that inhibits the formation of the metal-containing film 12 is selectively formed on the surface of the etching target 11 relative to the surface of the metal-containing film 12. The formation of the inhibition layer 14 shown in FIG. 10(b) is performed, for example, under the same conditions as the formation of the inhibition layer 14 shown in FIG.

[0067] When the inhibitory layer 14 is formed on the surface of the etching target 11, a small amount of the inhibitory layer 14 may also adhere to the surface of the metal-containing film 12. In this case, it is preferable to remove the inhibitory layer 14 adhered to the surface of the metal-containing film 12. This prevents the inhibitory layer 14 from inhibiting the formation of the metal-containing film 12 when the metal-containing film 12 is formed on the surface of the metal-containing film 12 in the next step. The inhibitory layer 14 is removed by the same method as that used to remove the inhibitory layer 14 in FIG. 1C, for example.

[0068] 10(c), a metal-containing film 12 is selectively formed on the metal-containing film 12 while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching target 11. This allows the thickness of the metal-containing film 12 to be increased. The selective formation of the metal-containing film 12 shown in FIG. 10(c) is performed under the same conditions as the selective formation of the metal-containing film 12 shown in FIG. 4(c), for example.

[0069] When the metal-containing film 12 is formed on the surface of the metal-containing film 12, a small amount of the metal-containing film 12 may also adhere to the surface of the inhibition layer 14. In this case, it is preferable to remove the metal-containing film 12 that has adhered to the surface of the inhibition layer 14. This prevents the etching of the etching target 11 from being inhibited by the metal-containing film 12 when the etching target 11 is etched in the next step. The removal of the metal-containing film 12 is performed, for example, by the same method as that used to remove the metal-containing film 12 in FIG. 4( c ).

[0070] Next, as shown in (d) of FIG. 10 , the etching target 11 is etched using the metal-containing film 12 as a mask. As a result, regions of the etching target 11 that are not covered with the metal-containing film 12 are etched, and recess structures 13 are formed. The etching of the etching target 11 shown in (d) of FIG. 10 is performed under the same conditions as, for example, the etching of the etching target 11 shown in (d) of FIG. 4 . When the etching target 11 is etched, the metal-containing film 12 may be etched, resulting in a decrease in the thickness of the metal-containing film 12. In this manner, recess structures 13 can be formed on the surface of the etching target 11.

[0071] According to the etching method of the tenth embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0072] (Eleventh Example) An etching method according to an eleventh example of the embodiment will be described with reference to Fig. 11. Fig. 11 is a cross-sectional view showing an etching method according to an eleventh example of the embodiment.

[0073] The etching method of Fig. 11 differs from the etching method of Fig. 10 in that the formation of an inhibition layer 14 on the surface of an etching target 11 shown in (b) and the selective deposition of a metal-containing film 12 shown in (c) are repeated multiple times in this order. The etching method of Fig. 11 is otherwise the same as the etching method of Fig. 10.

[0074] According to the etching method of the eleventh embodiment, the metal-containing film 12 is thickened while the inhibition layer 14 inhibits the formation of the metal-containing film 12 on the surface of the etching object 11, and the etching object 11 is etched using the thickened metal-containing film 12 as a mask. In this case, a recess structure 13 with a high aspect ratio can be formed in the etching object 11.

[0075] According to the etching method of the eleventh embodiment, the formation of the inhibition layer 14 on the surface of the etching target 11 and the selective deposition of the metal-containing film 12 are repeated multiple times in this order. In this case, the metal-containing film 12 can be deposited thickly, and therefore the depth of the recess structure 13 that can be formed by a single etching process can be increased.

[0076] [Modification of the Substrate] Another example of the substrate 10 will be described with reference to Fig. 12. Fig. 12 is a cross-sectional view showing another example of the substrate 10.

[0077] As shown in FIG. 12A , substrate 10 includes an etching object 11 and a metal-containing film 12. Etching object 11 includes a surface of dielectric film 11a and a surface of metal-containing film 11b. Metal-containing film 12 is provided on the surface of etching object 11. Metal-containing film 12 includes opening 12a. Opening 12a is provided on metal-containing film 11b. In this case, by etching metal-containing film 11b using the etching methods according to the first to eleventh embodiments, a recess structure 13 with a high aspect ratio can be formed in etching object 11, as shown in FIG. 12B .

[0078] 12, when metal-containing film 12 is a ruthenium film, dielectric film 11a is made of a material that easily adsorbs ruthenium, and metal-containing film 11b is made of a material that does not easily adsorb ruthenium. Dielectric film 11a is made of, for example, a material having hydroxyl (OH) groups on its surface or a material having dangling bonds on its surface. Metal-containing film 11b is made of, for example, a noble metal.

[0079] 13, a further example of the substrate 10 will be described. FIG. 13 is a cross-sectional view showing a further example of the substrate 10.

[0080] As shown in FIG. 13A , substrate 10 includes an etching object 11 and a metal-containing film 12. Etching object 11 includes a surface of dielectric film 11a and a surface of metal-containing film 11b. Metal-containing film 12 is provided on the surface of etching object 11. Metal-containing film 12 includes opening 12a. Opening 12a is provided on dielectric film 11a. In this case, by etching dielectric film 11a using the etching methods according to the first to eleventh embodiments, a recess structure 13 with a high aspect ratio can be formed in etching object 11, as shown in FIG. 13B .

[0081] 13, when metal-containing film 12 is a ruthenium film, dielectric film 11a is made of a material that does not easily adsorb ruthenium, and metal-containing film 11b is made of a material that easily adsorbs ruthenium. Dielectric film 11a is made of, for example, a material having a siloxane bond or a material having a halogen group on its surface. Metal-containing film 11b is made of, for example, a transition metal.

[0082] [Processing System] An example of a processing system PS used in the etching methods according to the first to eleventh embodiments will be described with reference to Fig. 14. Fig. 14 is a diagram showing the processing system PS according to the embodiment.

[0083] The processing system PS includes process modules PM1 to PM4, a transfer module TM, load lock modules LLM1 to LLM3, a loader module LM, load ports LP1 to LP4, and a control circuit CC.

[0084] The process modules PM1 to PM4 are connected to the transfer module TM via gate valves G11 to G14, respectively. The process modules PM1 to PM4 are depressurized to a predetermined vacuum atmosphere. The process modules PM1 to PM4 perform desired processing on the substrate 10 inside. The process module PM1 is, for example, a module for forming an inhibition layer 14. The process module PM2 is, for example, a module for forming a metal-containing film 12. The process module PM3 is, for example, a module for removing the inhibition layer 14 adhering to the surface of the metal-containing film 12 and the metal-containing film 12 adhering to the surface of the inhibition layer 14. The process module PM4 is, for example, a module for etching the etching target 11.

[0085] The interior of the transfer module TM is depressurized to a predetermined vacuum atmosphere. A vacuum transfer robot TR1 is provided inside the transfer module TM. The vacuum transfer robot TR1 transfers substrates 10 to the process modules PM1 to PM4 and the load lock modules LLM1 to LLM3.

[0086] The load lock modules LLM1 to LLM3 are connected to the transfer module TM via gate valves G21 to G23, respectively. The load lock modules LLM1 to LLM3 are connected to the loader module LM via gate valves G31 to G33, respectively. The interior of the load lock modules LLM1 to LLM3 can be switched between an air atmosphere and a vacuum atmosphere.

[0087] The inside of the loader module LM is an atmospheric atmosphere. A downflow of clean air is formed inside the loader module LM. An aligner (not shown) may be provided inside the loader module LM. The aligner aligns the substrate 10. An atmospheric transfer robot TR2 is provided inside the loader module LM. The atmospheric transfer robot TR2 transfers the substrate 10 to the load lock modules LLM1 to LLM3, carriers (not shown) on the load ports LP1 to LP4, and the aligner.

[0088] The load ports LP1 to LP4 are provided on the wall surface of the loader module LM. Carriers (not shown) are attached to the load ports LP1 to LP4. The carriers are, for example, front opening unified pods (FOUPs).

[0089] The control circuit CC is an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), etc. The control circuit CC executes various control operations described in this specification by executing instruction codes stored in a memory or by being a circuit designed for a specific application.

[0090] For example, the control circuit CC controls the operation of the process modules PM1 to PM4 and the operation of the load lock modules LLM1 to LLM3. For example, the control circuit CC controls the opening and closing of the gate valves G11 to G14, G21 to G23, and G31 to G33. For example, the control circuit CC controls the operation of the vacuum transfer robot TR1 and the operation of the atmospheric transfer robot TR2.

[0091] Next, an example of the operation of the processing system PS when performing the etching method according to the first embodiment will be described. In the following description, the opening and closing of the gate valves G11 to G14, G21 to G23, and G31 to G33 will be omitted.

[0092] First, a carrier containing a substrate 10 is attached to the load port LP1. The substrate 10 has an etching target 11 and a metal-containing film 12. Next, the atmospheric transfer robot TR2 transfers the substrate 10 from the carrier attached to the load port LP1 to the load lock module LLM1. Next, the load lock module LLM1 switches its interior from an atmospheric atmosphere to a vacuum atmosphere. Next, the vacuum transfer robot TR1 transfers the substrate 10 from the load lock module LLM1 to the process module PM4.

[0093] Next, the process module PM4 etches the etching object 11 using the metal-containing film 12 as a mask. As a result, a region of the etching object 11 that is not covered with the metal-containing film 12 is etched, and a recess structure 13 is formed. Next, the vacuum transfer robot TR1 transfers the substrate 10 from the process module PM4 to the process module PM1.

[0094] Next, the process module PM1 selectively forms an inhibition layer 14 that inhibits the formation of the metal-containing film 12 on the surface of the recess structure 13 relative to the surface of the metal-containing film 12. Next, the vacuum transfer robot TR1 transfers the substrate 10 from the process module PM1 to the process module PM2.

[0095] Next, process module PM2 selectively deposits metal-containing film 12 on metal-containing film 12 while using inhibition layer 14 to inhibit deposition of metal-containing film 12 on the surface of recess structure 13. This allows the thickness of metal-containing film 12 to be increased. Next, vacuum transfer robot TR1 transfers substrate 10 from process module PM2 to process module PM4.

[0096] Next, the process module PM4 etches the inhibition layer 14 and the etching object 11 using the metal-containing film 12 as a mask. As a result, a region of the etching object 11 that is not covered with the metal-containing film 12 is etched, and the depth of the recess structure 13 becomes deeper.

[0097] Next, the vacuum transfer robot TR1 transfers the substrate 10 from the process module PM4 to the load lock module LLM3. Next, the load lock module LLM3 switches its interior from a vacuum atmosphere to an atmospheric atmosphere. Next, the atmospheric transfer robot TR2 transfers the substrate 10 from the load lock module LLM3 to a carrier attached to the load port LP2. This completes the processing for one substrate 10.

[0098] In the above-described operation of the processing system PS, the formation of the inhibition layer 14, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 are performed in different process modules, but this is not limiting. For example, two or more of the formation of the inhibition layer 14, the selective deposition of the metal-containing film 12, and the etching of the etching target 11 may be performed in the same process module.

[0099] The etching methods according to the second to eleventh embodiments can also be performed in the processing system PS described above, similarly to the etching method according to the first embodiment.

[0100] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0101] REFERENCE SIGNS LIST 10 Substrate 11 Etching object 12 Metal-containing film 12a Opening 13 Recess structure 14 Inhibition layer

Claims

1. An etching method comprising the steps of: preparing a substrate having an etching object having a metal-containing film with an opening formed on its surface; and etching the etching object, wherein the etching step comprises the steps of: (a) etching the etching object using the metal-containing film as a mask; (b) selectively forming an inhibition layer that inhibits the formation of the metal-containing film on the surface of the etched etching object; (c) forming the metal-containing film on the surface of the metal-containing film while using the inhibition layer to inhibit the formation of the metal-containing film on the surface of the etching object; and (d) etching the inhibition layer and the etching object using the metal-containing film as a mask.

2. The etching method according to claim 1, wherein the etching step includes: (e) repeating the steps (b), (c), and (d) in this order a plurality of times.

3. The etching method according to claim 2, wherein the etching step includes: (f) repeating the steps (b) and (c) in this order a plurality of times.

4. An etching method according to any one of claims 1 to 3, wherein the etching step comprises: (g) a step of selectively forming the inhibition layer on the surface of the object to be etched before the step (a); and (h) a step of forming the metal-containing film on the surface of the metal-containing film while using the inhibition layer to inhibit the formation of the metal-containing film on the surface of the object to be etched between the steps (g) and (a).

5. The etching method according to claim 4, wherein the etching step includes: (i) repeating the steps (g) and (h) in this order a plurality of times.

6. The etching method according to any one of claims 1 to 3, wherein in step (b), an inhibition layer is formed on at least a portion of the surface of the metal-containing film, and the etching step includes the step of: (j) removing the inhibition layer formed on the surface of the metal-containing film between steps (b) and (c).

7. The etching method according to claim 4, wherein in step (h), the metal-containing film is formed on at least a portion of the surface of the inhibition layer, and the etching step includes the step of: (k) removing the metal-containing film formed on the surface of the inhibition layer between step (h) and step (a).

8. An etching method comprising the steps of: preparing a substrate having an etching object having a metal-containing film with an opening formed on its surface; and etching the etching object, wherein the etching step comprises the steps of: (p) selectively forming an inhibition layer that inhibits the formation of the metal-containing film on the surface of the etching object; (q) forming the metal-containing film on the surface of the metal-containing film while using the inhibition layer to inhibit the formation of the metal-containing film on the surface of the etching object; and (r) etching the inhibition layer and the etching object using the metal-containing film as a mask.

9. The etching method according to claim 8, wherein the etching step includes: (s) repeating the steps (p) and (q) in this order a plurality of times.

10. The etching method according to claim 8 or 9, wherein in step (q), the metal-containing film is formed on at least a portion of the surface of the inhibition layer, and the etching step includes: (t) a step of removing the metal-containing film formed on the surface of the metal-containing film between step (q) and step (r).

11. The etching method according to claim 1 or 8, wherein the preparing step comprises the steps of: preparing the etching object having a first surface of a dielectric film and a second surface of a second metal-containing film; and forming the metal-containing film on one of the first surface and the second surface, and forming the opening on the other of the first surface and the second surface.

12. The etching method according to claim 11, wherein the one surface is the first surface.

13. The etching method according to claim 11, wherein the one surface is the second surface.

14. A processing system for etching an etching object on a substrate having an etching object with a metal-containing film having an opening formed on its surface, the processing system comprising: a transfer module with a reduced pressure inside; a first process module, a second process module, and a third process module connected to the transfer module; and a control unit, wherein the control unit is configured to: control the first process module to etch the etching object using the metal-containing film as a mask; control the second process module to selectively form an inhibition layer that inhibits formation of the metal-containing film on the surface of the etched etching object; control the third process module to form the metal-containing film on the surface of the metal-containing film while inhibiting formation of the metal-containing film on the surface of the etching object with the inhibition layer; and control the first process module to etch the inhibition layer and the etching object using the metal-containing film as a mask.

15. A processing system for etching an etching object of a substrate having an etching object with a metal-containing film having an opening formed on its surface, the processing system comprising: a transfer module with a reduced pressure inside; a fourth process module, a fifth process module, and a sixth process module connected to the transfer module; and a control circuit, wherein the control circuit is configured to: control the fourth process module to selectively form an inhibition layer that inhibits the formation of the metal-containing film on the surface of the etching object; control the fifth process module to form the metal-containing film on the surface of the metal-containing film while using the inhibition layer to inhibit the formation of the metal-containing film on the surface of the etching object; and control the sixth process module to etch the inhibition layer and the etching object using the metal-containing film as a mask.

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