Substrate processing device, substrate processing method and chemical solution

Abstract

[Subject] Provide: A substrate processing apparatus, a substrate processing method, and a chemical solution capable of suppressing surface roughness of a metal film after etching. [Solution] A substrate processing apparatus comprises: a substrate rotating unit that holds and rotates a substrate having a metal film formed on its surface; a first supply unit that supplies a first processing liquid containing a chelating agent and a solvent to the substrate; a second supply unit that supplies a second processing liquid containing water to the substrate; and a control unit for controlling the substrate rotating unit, the first supply unit, and the second supply unit, wherein the control unit rotates the substrate via the substrate rotating unit while supplying the first processing liquid to the substrate via the first supply unit to generate a complex containing the metal and the chelating agent, and after generating the complex, supplies the second processing liquid to the substrate via the second supply unit to dissolve the complex in the second processing liquid.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus, a substrate processing method, and a chemical solution. Background Art

[0002] Conventionally, in semiconductor manufacturing processes, there is known a method of removing a portion of a metal film formed on a substrate such as a semiconductor wafer by supplying an etching solution having a pH of 7 or higher containing a chelating agent to the metal film (see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-181984 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present disclosure provides a substrate processing apparatus, a substrate processing method, and a chemical solution capable of suppressing surface roughness of a metal film after etching.

[0008] Solutions for solving problems

[0009] A substrate processing apparatus according to one embodiment of the present disclosure comprises: a substrate rotating portion that holds and rotates a substrate having a metal film formed on its surface; a first supply portion that supplies a first processing liquid containing a chelating agent and a solvent to the substrate; a second supply portion that supplies a second processing liquid containing water to the substrate; and a control portion for controlling the substrate rotating portion, the first supply portion, and the second supply portion, wherein the control portion rotates the substrate through the substrate rotating portion while supplying the first processing liquid to the substrate through the first supply portion and generating a complex containing the metal and the chelating agent, and after generating the complex, supplies the second processing liquid to the substrate through the second supply portion and dissolves the complex in the second processing liquid.

[0010] Effects of the Invention

[0011] According to the present disclosure, surface roughness of the metal film after etching can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is an explanatory diagram of the outline of the substrate processing method according to the embodiment.

[0013] Figure 2 A detailed explanatory diagram of a substrate processing method according to an embodiment.

[0014] Figure 3It is a diagram showing a schematic configuration of a substrate processing system according to an embodiment.

[0015] Figure 4 A diagram showing a schematic configuration of an etching unit.

[0016] Figure 5 is a flow chart illustrating steps of substrate processing performed by the substrate processing system.

[0017] Figure 6 This is a flowchart showing a first example of the steps of the etching process.

[0018] Figure 7 This is a flowchart showing a second example of the etching process steps.

[0019] Description of Reference Numerals

[0020] W: wafer

[0021] 18: Control Department

[0022] 30: Substrate holding mechanism

[0023] 41: First Supply Unit

[0024] 42: Second supply unit

[0025] 43: The 3rd Supply Department

[0026] 44: 4th Supply Department

[0027] 110: Metal film

[0028] 111: Metal Atoms

[0029] 120: Interlayer insulation film

[0030] 130: Passivation film

[0031] 131: Oxide

[0032] 210: First treatment liquid

[0033] 211: Chelating agents

[0034] 212: Solvent

[0035] 213: Complex

[0036] 220: Second treatment liquid

[0037] 230: 3rd treatment liquid DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In each of the drawings, identical or corresponding components are denoted by identical or corresponding reference numerals, and their description may be omitted.

[0039] <1. Substrate Processing Method>

[0040] First, refer to Figure 1 An overview of the substrate processing method according to the embodiment will be described. Figure 1 It is an explanatory diagram of the outline of the substrate processing method according to the embodiment.

[0041] like Figure 1 As shown, the substrate processing method of the embodiment is a method for reducing the thickness of the metal film 110 by removing a portion of the metal film 110 formed on a substrate such as a semiconductor wafer (hereinafter referred to as wafer W). It should be noted that the metal film 110 is provided inside a recessed portion 121 such as a wiring trench or a via formed in the interlayer insulating film 120. The interlayer insulating film 120 is, for example, a low dielectric constant film (Low-k film) and is formed on the surface of the wafer W. For example, before processing, as Figure 1 As shown in (a), the surface of the metal film 110 is flush with the surface of the interlayer insulating film 120. After processing, as shown in FIG. Figure 1 As shown in (b), the surface of the metal film 110 is closer to the wafer W than the surface of the interlayer insulating film 120. It should be noted that the substrate processing method disclosed herein is not limited to the method of thinning the metal film 110 in the recess 121 of this embodiment, and can also be used for precision etching of the entire surface of the wafer W.

[0042] Next, refer to Figure 2 The substrate processing method according to the embodiment will be described in detail. Figure 2 A detailed explanatory diagram of a substrate processing method according to an embodiment. Figure 2 In the Figure 1 The change of the region R shown by the two-dot chain line in FIG.

[0043] In the substrate processing method of the embodiment, first, a first processing liquid containing a chelating agent and a solvent is supplied to the metal film 110. Figure 2 As shown in (a), the metal film 110 includes metal atoms 111, and a passivation film 130 composed of, for example, an oxide 131 of the metal atoms 111 is formed on the surface of the metal film 110. For example, Figure 2 The passivation film 130 shown in (a) is a natural oxide film having a thickness of one atomic layer of metal atoms 111. By supplying the first treatment liquid 210 containing a chelating agent 211 and a solvent 212 to the metal film 110, Figure 2 As shown in (b), part of the chelating agent 211 adheres to the oxide 131, forming a complex 213 including the oxide 131 and the chelating agent 211. Since the oxide 131 includes the metal atom 111, the complex 213 includes the metal atom 111 and the chelating agent 211. The complex 213 is not easily soluble in the solvent 212.

[0044] Then, if Figure 2 As shown in (c), a water-soluble third treatment liquid 230 is supplied to the metal film 110. As a result, the complex 213 remains on the metal film 110, and the chelating agent 211 and the solvent 212 not attached to the oxide 131 are replaced by the third treatment liquid 230.

[0045] Then, if Figure 2 As shown in (d) of FIG, a second treatment liquid 220 containing water is supplied to the metal film 110. As a result, the complex 213 dissolves in the second treatment liquid 220. The second treatment liquid 220 inevitably contains dissolved oxygen. Therefore, when the complex 213 dissolves in the second treatment liquid 220, the metal atoms 111 located directly below the dissolved complex 213 are oxidized by the dissolved oxygen, and the oxide 131 is regenerated.

[0046] When all the complex 213 is dissolved in the second treatment liquid 220, Figure 2 As shown in FIG. 5( e ), a new passivation film 130 composed of a new oxide 131 is formed on the entire surface of the metal film 110 . In addition, the complex 213 is dissolved in the second treatment liquid 220 and removed from the metal film 110 .

[0047] In this way, one atomic layer of metal atoms 111 can be removed from the metal film 110. In addition, by repeatedly supplying the first processing liquid 210 ( Figure 2 (b)) to the removal of complex 213 ( Figure 2 By performing the treatment up to step (e)), the metal film 110 is removed one atomic layer at a time, and the metal film 110 can be thinned by multiple atomic layers of the metal atoms 111 .

[0048] Then, when the metal film 110 is thinned to a predetermined thickness, the supply of the first processing liquid 210 , the second processing liquid 220 , and the third processing liquid 230 is stopped, and the wafer W is rotated to dry the wafer W.

[0049] According to the substrate processing method of the embodiment, the surface roughness of the metal film 110 after etching can be suppressed. In other words, the metal film 110 can be thinned while maintaining the surface of the metal film 110 flat (see Figure 1 (b)).

[0050] It should be noted that, in the removal of complex 213 ( Figure 2 (e)) and the subsequent supply of the first processing liquid 210 ( Figure 2The wafer W can be dried between (b). When the complex 213 is dissolved in the second processing liquid 220 , even if the passivation film 130 is not sufficiently formed, the wafer W can be dried to promote the formation of the passivation film 130 .

[0051] In addition, in the initial supply of the first processing liquid 210 ( Figure 2 Before (b)), it is preferable to perform dry etching of the metal film 110 as a pretreatment. In the pretreatment, for example, it is preferable to use a fourth treatment liquid to remove foreign matter such as organic matter attached to the surface of the passivation film 130. By removing foreign matter in advance, it becomes easier to further maintain the flatness of the surface of the metal film 110.

[0052] The chelating agent 211 contained in the first treatment liquid 210 includes, for example, an organic acid containing one or more selected from the group consisting of a carbonyl group, a carboxyl group, and an amino group. Examples of such organic acids include citric acid, oxalic acid, malic acid, maleic acid, iminodiacetic acid, and ethylenediaminetetraacetic acid (EDTA). As the chelating agent 211 contained in the first treatment liquid 210, it is preferred to use a chelating agent that can coordinate with the oxide 131 of the metal (target metal) constituting the metal film 110 to be treated. For example, when the target metal is cobalt, citric acid and oxalic acid can be used as the chelating agent 211, and when the target metal is copper, oxalic acid can be used.

[0053] Isopropyl alcohol (IPA), for example, is used as the solvent 212 contained in the first treatment liquid 210. The solvent 212 may include one or more selected from the group consisting of isopropyl alcohol, acetone, N-methyl-2-pyrrolidone (NMP), and tetrahydrofuran.

[0054] The first treatment liquid 210 may further contain water in addition to the chelating agent 211 and the solvent 212. However, the water content of the first treatment liquid 210 is preferably 10% by mass or less, more preferably 1% by mass or less. Furthermore, the first treatment liquid 210 is preferably composed of the chelating agent 211 and the solvent 212. The first treatment liquid 210 is an example of a chemical solution.

[0055] As the second treatment liquid 220, for example, a treatment liquid that has the effect of changing the surface of the metal film 110 to a state where it reacts with the chelating agent 211 to form the complex 213 is used. As the second treatment liquid 220, for example, pure water (DIW) is used. As the second treatment liquid 220, an aqueous solution prepared by dissolving a pH adjuster such as ammonia (NH3) or carbon dioxide (CO2) in DIW can also be used. In order to suppress etching of the metal film 110 by the second treatment liquid 220, the pH of the second treatment liquid 220 is preferably 7 or above.

[0056] IPA is used as the third treatment liquid 230, for example. IPA is preferably soluble in the second treatment liquid 220 containing water. The solvent 212 and the third treatment liquid 230 may use the same liquid (or component), or the liquid (or component) of the solvent 212 and the liquid (or component) of the third treatment liquid 230 may be different.

[0057] As the fourth treatment liquid, for example, an aqueous solution (SC1 liquid) containing NH4OH (ammonium hydroxide) and H2O2 (hydrogen peroxide) or dilute hydrofluoric acid (DHF) is used. As the fourth treatment liquid, heated IPA is used.

[0058] <2. Configuration of the Substrate Processing System>

[0059] Next, refer to Figure 3 The configuration of a substrate processing system for executing the above-mentioned substrate processing method will be described. Figure 3 1 is a diagram showing a schematic configuration of a substrate processing system according to an embodiment. In the following, to clarify the positional relationship, the X-axis, Y-axis, and Z-axis are defined as being orthogonal to each other, and the positive direction of the Z-axis is defined as being vertically upward.

[0060] like Figure 3 As shown, the substrate processing system 1 includes a loading / unloading stage 2 and a processing stage 3. The loading / unloading stage 2 and the processing stage 3 are provided adjacent to each other.

[0061] The loading / unloading stage 2 includes a carrier placement portion 11 and a conveying portion 12. A plurality of carriers C for storing a plurality of wafers W in a horizontal state are placed on the carrier placement portion 11.

[0062] As described above, the interlayer insulating film 120 is formed on the surface of the wafer W, and the metal film 110 is formed in the recessed portion 121 such as a wiring trench or a via formed on the surface of the interlayer insulating film 120 .

[0063] The transport unit 12 is disposed adjacent to the carrier mounting unit 11 and includes a substrate transport device 13 and a transfer unit 14 therein. The substrate transport device 13 includes a wafer holding mechanism for holding the wafer W. The substrate transport device 13 is capable of horizontal and vertical movement and rotation about a vertical axis, and uses the wafer holding mechanism to transport the wafer W between the carrier C and the transfer unit 14.

[0064] The processing station 3 is provided adjacent to the conveying section 12. The processing station 3 includes a conveying section 15 and a plurality of etching units 16. The plurality of etching units 16 are arranged on both sides of the conveying section 15. It should be noted that the number of etching units 16 is not limited to Figure 3 Example shown.

[0065] The conveying unit 15 includes a substrate conveying device 17 therein. The substrate conveying device 17 includes a wafer holding mechanism for holding the wafer W. The substrate conveying device 17 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and uses the wafer holding mechanism to convey the wafer W between the transfer unit 14 and the etching unit 16.

[0066] The etching unit 16 performs predetermined substrate processing on the wafer W conveyed by the substrate conveying device 17 .

[0067] Furthermore, the substrate processing system 1 includes a control device 4 . The control device 4 includes a control unit 18 and a storage unit 19 .

[0068] The control unit 18 includes, for example, a microcomputer including a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output ports, and various circuits. The CPU of the control unit 18 uses the RAM as a work area and executes programs stored in the ROM to control the operation of the substrate processing system 1.

[0069] It should be noted that the above-mentioned program is stored in a computer-readable storage medium and can be installed from the storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), and a memory card.

[0070] The storage unit 19 is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk.

[0071] <3. Etching Unit Configuration>

[0072] Next, refer to Figure 4 The configuration of the etching unit 16 will be described. Figure 4 It is a diagram showing a schematic configuration of the etching unit 16 .

[0073] like Figure 4 As shown, the etching unit 16 includes a chamber 20 , a substrate holding mechanism 30 , a first supply unit 41 , a second supply unit 42 , a third supply unit 43 , a fourth supply unit 44 , and a recovery cup 50 .

[0074] The chamber 20 houses a substrate holding mechanism 30, a first supply unit 41, a second supply unit 42, a third supply unit 43, a fourth supply unit 44, and a recovery cup 50. A fan filter unit (FFU) 21 is provided at the top of the chamber 20. The FFU 21 forms a downflow within the chamber 20.

[0075] The substrate holding mechanism 30 includes a holding portion 31 , a support column 32 , and a driving portion 33 . The holding portion 31 holds the wafer W horizontally. The wafer W is held by the holding portion 31 with the surface on which the metal film 110 is formed facing upward.

[0076] In this embodiment, the holding portion 31 includes a plurality of fixing portions 31 a , which fix the peripheral edge of the wafer W and thereby hold the wafer W. However, the present invention is not limited thereto, and the holding portion 31 may be a vacuum chuck that holds the wafer W by suction.

[0077] The support 32 is a member extending in the vertical direction. Its base end is rotatably supported by a drive unit 33, and its tip end horizontally supports the holding unit 31. The drive unit 33 rotates the support 32 about a vertical axis. The substrate holding mechanism 30 described above rotates the support 32 using the drive unit 33, thereby rotating the holding unit 31 supported by the support 32, thereby rotating the wafer W held by the holding unit 31.

[0078] The first supply unit 41 , the second supply unit 42 , the third supply unit 43 , and the fourth supply unit 44 are arranged above the wafer W held by the holding unit 31 .

[0079] The first supply unit 41 is connected to one end of the first supply passage 61, and the other end of the first supply passage 61 is connected to a first supply source 71 of the first processing liquid 210. A first flow control valve 81 is inserted midway through the first supply passage 61 to open and close the first supply passage 61 and adjust the supply flow rate of the first processing liquid 210. Therefore, when the first flow control valve 81 is opened, the first processing liquid 210 is supplied from the first supply unit 41 to the wafer W held by the holding unit 31. As a result, the first processing liquid 210 is supplied to the metal film 110 on the wafer W.

[0080] The second supply unit 42 is connected to one end of the second supply passage 62, and the other end of the second supply passage 62 is connected to a second supply source 72 for the second processing liquid 220. A second flow control valve 82 is inserted midway along the second supply passage 62 to open and close the second supply passage 62 and adjust the supply flow rate of the second processing liquid 220. Therefore, when the second flow control valve 82 is opened, the second processing liquid 220 is supplied from the second supply unit 42 to the wafer W held by the holding unit 31. As a result, the second processing liquid 220 is supplied to the metal film 110 on the wafer W.

[0081] The third supply unit 43 is connected to one end of the third supply passage 63, and the other end of the third supply passage 63 is connected to a third supply source 73 for the third processing liquid 230. A third flow control valve 83 is inserted midway along the third supply passage 63 to open and close the third supply passage 63 and adjust the supply flow rate of the third processing liquid 230. Therefore, when the third flow control valve 83 is opened, the third processing liquid 230 is supplied from the third supply unit 43 to the wafer W held by the holding unit 31. This supplies the third processing liquid 230 to the metal film 110 on the wafer W.

[0082] The fourth supply unit 44 is connected to one end of the fourth supply passage 64, and the other end of the fourth supply passage 64 is connected to a fourth supply source 74 of the fourth processing liquid. A fourth flow control valve 84 is inserted midway along the fourth supply passage 64 to open and close the fourth supply passage 64 and adjust the supply flow rate of the fourth processing liquid. Therefore, when the fourth flow control valve 84 is opened, the fourth processing liquid is supplied from the fourth supply unit 44 to the wafer W held by the holding unit 31. This supplies the fourth processing liquid to the metal film 110 on the wafer W.

[0083] The recovery cup 50 is arranged so as to surround the holding portion 31 and collects the first processing liquid 210, the second processing liquid 220, the third processing liquid 230, or the fourth processing liquid that is scattered from the wafer W due to the rotation of the holding portion 31. A drain port 51 is formed at the bottom of the recovery cup 50, and the first processing liquid 210, the second processing liquid 220, the third processing liquid 230, or the fourth processing liquid collected by the recovery cup 50 is discharged from the drain port 51 to the outside of the etching unit 16. In addition, an exhaust port 52 is formed at the bottom of the recovery cup 50 for discharging the gas supplied from the FFU 21 to the outside of the etching unit 16.

[0084] For example, when the metal film 110 is a cobalt film, that is, when the target metal is cobalt, the following treatment liquids can be used as the first treatment liquid 210, the second treatment liquid 220, the third treatment liquid 230, and the fourth treatment liquid. For example, the first treatment liquid 210 contains citric acid or oxalic acid as a chelating agent and IPA as a solvent. For example, the second treatment liquid 220 is DIW, the third treatment liquid 230 is IPA, and the fourth treatment liquid is SC1 or DHF. The pH of the DIW in the second treatment liquid 220 can be adjusted to above 7 using a pH adjuster such as NH3.

[0085] <4. Specific Operations of the Substrate Processing System>

[0086] Next, refer to Figure 5 The specific operation of the substrate processing system 1 will be described. Figure 5 1 is a flowchart showing the steps of substrate processing performed by the substrate processing system 1. Each device provided in the substrate processing system 1 performs the following operations under the control of the control unit 18: Figure 5 The processing steps shown.

[0087] like Figure 5 As shown, in the substrate processing system 1, the wafer W is first loaded into the etching unit 16 (step S101). Specifically, the substrate conveyor 13 of the loading / unloading stage 2 removes the wafer W from the carrier C placed on the carrier loading portion 11 and places the removed wafer W on the transfer portion 14. The wafer W placed on the transfer portion 14 is removed from the transfer portion 14 by the substrate conveyor 17 of the processing station 3 and loaded into the etching unit 16. The wafer W loaded into the etching unit 16 is held by the holding portion 31 of the etching unit 16.

[0088] Then, the substrate processing system 1 performs an etching process (step S102). During the etching process, the holding portion 31 holding the wafer W is rotated by the driving portion 33, and the processing liquid is supplied to the wafer W held by the holding portion 31 from the first supply portion 41, the second supply portion 42, the third supply portion 43, and the fourth supply portion 44. As a result, a portion of the metal film 110 on the wafer W is removed.

[0089] Here, the details of the etching process will be described. Figure 6 This is a flowchart showing a first example of the steps of the etching process. Figure 7 This is a flowchart showing a second example of the etching process steps.

[0090] In the first example, in the etching process (step S102 ), pre-processing (step S201 ) is first performed. In the pre-processing, the fourth processing liquid is supplied from the fourth supply unit 44 to the rotating wafer W, and foreign matter such as organic matter attached to the surface of the passivation film 130 is removed by the fourth processing liquid.

[0091] Next, a rinsing process is performed (step S202). During the rinsing process, the supply of the fourth processing liquid is stopped, and the rinsing liquid is supplied to the rotating wafer W. As a result, the fourth processing liquid remaining on the wafer W is removed. The rinsing liquid is, for example, DIW. In the case where the second processing liquid 220 is DIW, the second processing liquid 220 can be used as the rinsing liquid. In the case where the second processing liquid 220 also contains a pH adjuster in addition to DIW, a fifth supply unit connected to the DIW supply source is pre-set in the etching unit 16, and DIW can be supplied as the rinsing liquid from the fifth supply unit.

[0092] After that, a drying process is performed (step S203). During the drying process, the supply of the rinsing liquid is stopped while the wafer W is continuously rotated. Thus, the rinsing liquid remaining on the wafer W is removed and the wafer W is dried. During the drying process, a natural oxide film is formed on the surface of the metal film 110 in the form of a passivation film 130 including an oxide 131 (see FIG. Figure 2 (a)).

[0093] Then, a complexing process is performed (step S204). In the complexing process, a first processing liquid 210 containing a chelating agent 211 and a solvent 212 is supplied from the first supply unit 41 to the rotating wafer W to generate a complex 213 containing the oxide 131 and the chelating agent 211 (see Figure 2 (b)). The drying process (step S203) may be omitted, and the complexing process (step S204) may be performed after the rinsing process (step S202).

[0094] Next, a purge process is performed (step S205). During the purge process, the supply of the first processing liquid 210 is stopped, and the third processing liquid 230 is supplied from the third supply unit 43 to the rotating wafer W to remove the chelating agent 211 and the solvent 212 that are not attached to the oxide 131, thereby forming a liquid film of the third processing liquid 230 (see FIG. Figure 2 (c)).

[0095] Then, a dissolution process is performed (step S206). During the dissolution process, the supply of the third processing liquid 230 is stopped, and the second processing liquid 220 is supplied from the second supply unit 42 to the rotating wafer W, so that the complex 213 is dissolved in the second processing liquid 220, the complex 213 is removed from the metal film 110, and a new passivation film 130 is formed by the dissolved oxygen in the second processing liquid 220 (see FIG. Figure 2 (d) and Figure 2 (e)).

[0096] Then, the processing of steps S204 to S206 is repeated, and when the number of repetitions reaches a predetermined number of times (step S207), the etching process (step S102) is terminated.

[0097] After the etching process (step S102), the substrate processing system 1 performs a rinsing process (step S103). During the rinsing process, the supply of the second processing liquid 220 is stopped, and the rinsing liquid is supplied to the rotating wafer W. This removes the second processing liquid 220 remaining on the wafer W. If the second processing liquid 220 is DIW, the rinsing process (step S103) can be omitted.

[0098] Then, the substrate processing system 1 performs a drying process (step S104). During the drying process, the supply of the rinsing liquid is stopped while the wafer W continues to rotate. This removes the rinsing liquid remaining on the wafer W, drying the wafer W. IPA can be used to assist in drying.

[0099] Next, the substrate processing system 1 performs unloading (step S105). During the unloading process, the dried wafer W is unloaded from the etching unit 16 by the substrate conveyor 17 and placed on the transfer unit 14. The processed wafer W placed on the transfer unit 14 is then returned by the substrate conveyor 13 to the carrier C of the carrier placement unit 11. This completes the series of substrate processing steps for a single wafer W.

[0100] In the second example, first, similarly to the first example, the process from pre-processing (step S201) to dissolution processing (step S206) is performed.

[0101] Then, steps S204 to S206 are repeated. Once the number of repetitions reaches a predetermined first number (step S307), a drying process is performed (step S308). During the drying process, the supply of the second processing liquid 220 used in the dissolution process is stopped while the wafer W continues to rotate. This removes the second processing liquid 220 remaining on the wafer W, drying the wafer W. The passivation film 130 formed during the dissolution process remains intact.

[0102] Then, the processes of steps S204 to S206 and the drying process of step S308 are repeated. When the number of repetitions reaches a second predetermined number of times (step S309), the etching process (step S102) is terminated.

[0103] For example, the first predetermined number of times is 10 to 50 times, and the second predetermined number of times is 3 to 10 times. If the first predetermined number of times is 40 times and the second predetermined number of times is 5 times, first, the process of steps S204 to S206 is repeated 40 times, and then the drying process of step S308 is performed. This 40 repetitions of the process of steps S204 to S206 and the drying process of step S308 are combined as a set, and this set is repeated 5 times.

[0104] During the etching process of step S102, the first predetermined number of times can be changed. In this case, it is preferable to reduce the first predetermined number of times as the number of repetitions of the processes of steps S204 to S206 and the number of repetitions of the drying process of step S308 increases. For example, when the second predetermined number of times is 5, the first predetermined number of times is 40 times when the number of repetitions of the processes of steps S204 to S206 and the number of repetitions of the drying process of step S308 reaches 3, and the first predetermined number of times can be 30 times when the number of repetitions of the processes of steps S204 to S206 and the drying process of step S308 reaches 2. As the etching process progresses, the height difference between the surface of the metal film 110 and the surface of the interlayer insulating film 120 becomes larger. There is a concern that in step S204, it is difficult to replace the second processing liquid 220 with the first processing liquid 210, and it is difficult to form the complex 213. In contrast, as the etching process progresses, the first predetermined number of times is reduced to increase the frequency of the drying process in step S308 , thereby removing the second processing liquid 220 before step S204 and maintaining the ease of formation of the complex 213 in step S204 .

[0105] It should be noted that, during the dissolution process (step S206), when the liquid film of the second processing liquid 220 is formed on the entire surface of the wafer W, it is preferable for the control unit 18 to stop the supply of the second processing liquid 220 by the second supply unit 42 while continuing the rotation of the wafer W. As described above, as the second processing liquid 220 is supplied, a new passivation film 130 is formed on the surface of the metal film 110. This is because, at this time, if the metal film 110 is exposed to the second processing liquid 220 for a long time, there is a concern that newly formed oxides 131 will dissolve in the second processing liquid 220. If the newly formed oxides 131 dissolve in the second processing liquid 220, there is a concern that it will be difficult to remove a single layer of metal atoms 111 from the metal film 110 one by one.

[0106] The timing of stopping the supply of the second processing liquid 220 by the second supply unit 42 may not completely coincide with the timing of completion of liquid film formation. For example, assuming that the time from the start of supply of the second processing liquid 220 to the completion of liquid film formation is t, the supply of the second processing liquid 220 may be stopped when a time of 1.0 t or more and 1.1 t or less has elapsed since the start of supply of the second processing liquid 220.

[0107] The control unit 18 preferably controls the temperature of the second processing liquid 220 to be 25°C or lower. This is because if the temperature of the second processing liquid 220 exceeds 25°C, the newly generated oxide 131 will easily dissolve in the second processing liquid 220. For example, the control unit 18 controls the temperature of the second processing liquid 220 to be 20°C or higher and 25°C or lower, which is approximately room temperature. The control unit 18 preferably controls the temperature of the third processing liquid 230 to be approximately the same as the temperature of the second processing liquid 220. This is to suppress changes in the temperature of the second processing liquid 220 supplied to the wafer W.

[0108] The control unit 18 preferably controls the concentration of dissolved oxygen in the second treatment liquid 220 to be 600 ppb or less, and more preferably to be 500 ppb or less. This is because if the concentration of dissolved oxygen in the second treatment liquid 220 exceeds 600 ppb, there is a concern that the passivation film 130 may be excessively formed. On the other hand, it is extremely difficult to reduce the concentration of dissolved oxygen to below 100 ppb. In addition, if the concentration of dissolved oxygen is too low, there is a concern that it will become difficult to form a new passivation film 130. Therefore, for example, the control unit 18 sets the concentration of dissolved oxygen in the second treatment liquid 220 to be greater than 100 ppb and less than 600 ppb.

[0109] The control unit 18 preferably controls the pH of the second treatment liquid 220 according to the type of the target metal. A pH adjuster can be used to control the pH. By controlling the pH of the second treatment liquid 220, etching of the passivation film 130 by the second treatment liquid 220, such as DIW, can be suppressed. For example, when the target metal is cobalt or copper, NH3 can be used as the pH adjuster.

[0110] Thus, the substrate processing system 1 (an example of a substrate processing apparatus) according to the embodiment includes a substrate holding mechanism 30 (an example of a substrate rotating unit), a first supply unit 41, a second supply unit 42, and a control unit 18. The substrate holding mechanism 30 holds and rotates a wafer W (an example of a substrate) having a metal film 110 formed on its surface. The first supply unit 41 supplies a first processing liquid 210 containing a chelating agent 211 and a solvent 212 to the wafer W. The second supply unit 42 supplies a second processing liquid 220 containing water to the wafer W. The control unit 18 is configured to control the substrate holding mechanism 30, the first supply unit 41, and the second supply unit 42. The control unit 18 rotates the wafer W through the substrate holding mechanism 30, and supplies the first processing liquid 210 to the wafer W through the first supply unit 41 to generate a complex 213 containing the metal constituting the metal film 110 and the chelating agent 211. After the complex 213 is generated, the second processing liquid 220 is supplied to the wafer W through the second supply unit 42 to dissolve the complex 213 in the second processing liquid 220.

[0111] Therefore, according to the substrate processing system 1 of the embodiment, it is possible to suppress the surface roughness of the metal film 110 after etching.

[0112] The target metal is not limited to cobalt (Co) and copper (Cu). For example, the target metal may be ruthenium (Ru), molybdenum (Mo), or titanium nitride (TiN).

[0113] The substrate processing system 1 is provided with a first tank storing a first processing liquid 210 and a second tank for mixing a chelating agent and a solvent. The chelating agent and the solvent can be supplied to the second tank from a chelating agent supply source and a solvent supply source, respectively. In this case, the chelating agent and the solvent are mixed in the second tank, and the mixed liquid of the chelating agent and the solvent is transferred from the second tank to the first tank as the first processing liquid 210. The first processing liquid 210 is then supplied from the first tank to the first supply unit 41.

[0114] Preferred embodiments and the like have been described in detail above, but the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions may be made to the above-described embodiments and the like without departing from the scope of the claims.

Claims

1. A substrate processing apparatus comprising: a substrate rotating unit that holds and rotates a substrate having a metal film formed on its surface; a first supply unit for supplying a first processing liquid containing a chelating agent and a solvent to the substrate; a second supply unit that supplies a second processing liquid containing water to the substrate; and a control unit for controlling the substrate rotating unit, the first supply unit, and the second supply unit, The control unit rotates the substrate via the substrate rotating unit and supplies the first processing liquid to the substrate via the first supply unit to generate a complex containing the metal and the chelating agent. After the complex is generated, the second processing liquid is supplied to the substrate by the second supply unit to dissolve the complex in the second processing liquid. A passivation film composed of an oxide of metal atoms is formed on the surface of the metal film, and when the first processing liquid is supplied to the substrate, a portion of the chelating agent adheres to the oxide to form a complex containing the oxide and the chelating agent. The substrate processing apparatus further includes a third supply unit configured to supply a water-soluble third processing liquid to the substrate. The control unit supplies the third processing liquid to the substrate through the third supply unit after the complex is generated and before the second processing liquid is supplied, thereby removing the chelating agent remaining on the substrate.

2. The substrate processing apparatus according to claim 1, wherein: The second treatment liquid is water or an aqueous solution.

3. The substrate processing apparatus according to claim 1 or 2, wherein: The control unit stops supply of the second processing liquid by the second supply unit when a liquid film of the second processing liquid is formed on the entire surface of the substrate.

4. The substrate processing apparatus according to claim 1 or 2, wherein: The control unit repeatedly supplies the first processing liquid by the first supply unit and the second processing liquid by the second supply unit while rotating the substrate by the substrate rotating unit.

5. The substrate processing apparatus according to claim 1 or 2, wherein: The control unit controls the temperature of the second processing liquid to be 25° C. or lower.

6. The substrate processing apparatus according to claim 1 or 2, further comprising a fourth supply unit configured to supply a fourth processing liquid capable of removing foreign matter attached to the surface of the metal film to the substrate. The control unit may supply the fourth processing liquid to the substrate by the fourth supply unit while rotating the substrate by the substrate rotating unit before supplying the first processing liquid.

7. The substrate processing apparatus according to claim 1 or 2, wherein: The control unit continues the rotation of the substrate and dries the surface of the substrate after supplying the second processing liquid.

8. The substrate processing apparatus according to claim 1 or 2, wherein: The control unit rotates the substrate via the substrate rotating unit while repeating the supply of the first processing liquid by the first supply unit and the supply of the second processing liquid by the second supply unit for a first time. After repeating the first number of times, the substrate is rotated continuously and the surface of the substrate is dried for the first time. The first repetition and the first drying are repeated a second time.

9. The substrate processing apparatus according to claim 8, wherein: The control unit decreases the first number of times as the first number of repetitions and the number of repetitions of the first drying increase.

10. A substrate processing method comprising the following steps: a step of supplying a first treatment liquid containing a chelating agent and a solvent to a substrate having a metal film formed on its surface while rotating the substrate to generate a complex containing the metal and the chelating agent; and After the step of generating the complex, a step of supplying a second treatment liquid containing water to the substrate while rotating the substrate and dissolving the complex in the second treatment liquid is performed. A passivation film composed of an oxide of metal atoms is formed on the surface of the metal film, and in the step of supplying the first processing liquid to the substrate, a portion of the chelating agent adheres to the oxide to form a complex containing the oxide and the chelating agent. in, After the step of generating the complex and before the step of supplying the second treatment liquid, a step of supplying a water-soluble third treatment liquid to the substrate to remove the chelating agent remaining on the substrate is provided.

11. The substrate processing method according to claim 10, wherein: The second treatment liquid is water or an aqueous solution.

12. The substrate processing method according to claim 10 or 11, wherein: The process of supplying the second treatment liquid includes the following steps: When a liquid film of the second processing liquid is formed on the entire surface of the substrate, supply of the second processing liquid is stopped.

13. The substrate processing method according to claim 10 or 11, wherein: The step of supplying the first processing liquid and the step of supplying the second processing liquid are repeated.

14. The substrate processing method according to claim 10 or 11, wherein: The temperature of the second treatment liquid is controlled to be 25° C. or lower.

15. The substrate processing method according to claim 10 or 11, wherein: Before the step of supplying the first processing liquid, a step of supplying a fourth processing liquid capable of removing foreign matter attached to the surface of the metal film to the substrate while rotating the substrate is provided.

16. The substrate processing method according to claim 10 or 11, wherein: After the step of supplying the second processing liquid, the method includes a step of drying the surface of the substrate while continuing the rotation of the substrate.

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