WO2023166970A1

WO2023166970A1 - Substrate processing method

Info

Publication number: WO2023166970A1
Application number: PCT/JP2023/004908
Authority: WO
Inventors: 祐希吉田; 興司香川
Original assignee: 東京エレクトロン株式会社
Priority date: 2022-03-01
Filing date: 2023-02-14
Publication date: 2023-09-07
Also published as: TW202403869A

Abstract

A substrate processing method according to one embodiment of the present disclosure comprises an etching step. In the etching step, an etching liquid is supplied to a substrate, on the surface of which at least one of a zirconium oxide film and a hafnium oxide film is formed, so as to etch at least one of the zirconium oxide film and the hafnium oxide film. In addition, an etching liquid to which methanesulfonic acid has been added is supplied to the substrate in the etching step.

Description

Substrate processing method

The disclosed embodiments relate to substrate processing methods.

Conventionally, there has been known a technique of selectively etching a metal film of a high dielectric constant insulating material formed on a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer). This technique uses an etching solution to which a chelating agent is added (see Patent Document 1).

Japanese Patent No. 5050850

The present disclosure provides a technique capable of satisfactorily removing at least one of a zirconium oxide film and a hafnium oxide film from a substrate.

A substrate processing method according to one aspect of the present disclosure includes an etching process. In the etching step, an etchant is supplied to a substrate on which at least one of a zirconium oxide film and a hafnium oxide film is formed, and at least one of the zirconium oxide film and the hafnium oxide film is etched. In the etching step, the etchant to which methanesulfonic acid is added is supplied to the substrate.

According to the present disclosure, at least one of the zirconium oxide film and the hafnium oxide film can be satisfactorily removed from the substrate.

FIG. 1 is a schematic diagram showing a schematic configuration of a substrate processing system according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of a specific configuration of a processing unit according to the embodiment; FIG. 3 is a schematic diagram showing an example of the state of the wafer surface after preparatory processing according to the embodiment. FIG. 4 is a diagram showing an SEM observation photograph after an etching treatment test of a zirconium oxide film according to the present disclosure. FIG. 5 is a diagram showing an SEM observation photograph after a zirconium oxide film etching treatment test in the present disclosure. FIG. 6 is a diagram showing an SEM observation photograph after an etching treatment test of a zirconium oxide film in the present disclosure. FIG. 7 is a diagram showing an SEM observation photograph after an etching treatment test of a zirconium oxide film according to the present disclosure. FIG. 8 is a diagram showing an SEM observation photograph after an etching treatment test of a hafnium oxide film according to the present disclosure. FIG. 9 is a diagram showing an SEM observation photograph after an etching treatment test of a hafnium oxide film according to the present disclosure. FIG. 10 is a diagram showing an SEM observation photograph after an etching treatment test of a hafnium oxide film according to the present disclosure. FIG. 11 is a diagram showing an SEM observation photograph after an etching treatment test of a hafnium oxide film according to the present disclosure. FIG. 12 is a diagram showing an SEM observation photograph after another etching treatment test of the zirconium oxide film in the present disclosure. FIG. 13 is a diagram showing an SEM observation photograph after another etching treatment test of the zirconium oxide film in the present disclosure. FIG. 14 is a diagram showing an SEM observation photograph after an etching treatment test of the zirconium oxide film in the modified example of the present disclosure. FIG. 15 is a diagram showing an SEM observation photograph after an etching treatment test of the zirconium oxide film in the modified example of the present disclosure. FIG. 16 is a diagram showing an SEM observation photograph after another etching treatment test of the zirconium oxide film in the modified example of the present disclosure. FIG. 17 is a diagram showing an SEM observation photograph after another etching treatment test of the zirconium oxide film in the modified example of the present disclosure. FIG. 18 is a flow chart showing a procedure of substrate processing executed by the substrate processing system according to the embodiment. FIG. 19 is a flowchart illustrating a procedure of substrate processing performed by the substrate processing system according to the modification of the embodiment;

Hereinafter, embodiments of the substrate processing method disclosed in the present application will be described in detail with reference to the accompanying drawings. It should be noted that the present disclosure is not limited by the embodiments shown below. Also, it should be noted that the drawings are schematic, and the relationship of dimensions of each element, the ratio of each element, and the like may differ from reality. Furthermore, even between the drawings, there are cases where portions having different dimensional relationships and ratios are included.

Conventionally, there has been known a technique of selectively etching a metal film of a high dielectric constant insulating material formed on a substrate such as a semiconductor wafer (hereinafter also referred to as a wafer). This technique uses an etching solution to which a chelating agent is added.

On the other hand, when attempting to etch a zirconium oxide film, a hafnium oxide film, a lanthanum oxide film, or a cerium oxide film formed on a substrate by applying the above-described conventional techniques, it is very difficult to satisfactorily remove them without residue. Met.

Therefore, the realization of a technique capable of overcoming the above-mentioned problems and satisfactorily removing at least one of the zirconium oxide film and the hafnium oxide film from the substrate is expected.

<Overview of substrate processing system>
First, a schematic configuration of a substrate processing system 1 according to an embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of a substrate processing system 1 according to an embodiment. Hereinafter, in order to clarify the positional relationship, the X-axis, Y-axis and Z-axis are defined to be orthogonal to each other, and the positive direction of the Z-axis is defined as the vertically upward direction.

As shown in FIG. 1, the substrate processing system 1 includes a loading/unloading station 2 and a processing station 3 . The loading/unloading station 2 and the processing station 3 are provided adjacently.

The loading/unloading station 2 includes a carrier placement section 11 and a transport section 12 . A plurality of carriers C for accommodating a plurality of substrates, in the embodiment, semiconductor wafers W (hereinafter referred to as wafers W) in a horizontal state are placed on the carrier platform 11 .

The transport section 12 is provided adjacent to the carrier mounting section 11 and includes a substrate transport device 13 and a transfer section 14 therein. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. As shown in FIG. Further, the substrate transfer device 13 can move in the horizontal direction and the vertical direction and can rotate about the vertical axis. conduct.

The processing station 3 is provided adjacent to the transport section 12 . The processing station 3 comprises a transport section 15 and a plurality of processing units 16 . A plurality of processing units 16 are arranged side by side on both sides of the transport section 15 .

The transport unit 15 includes a substrate transport device 17 inside. The substrate transfer device 17 includes a wafer holding mechanism that holds the wafer W. As shown in FIG. In addition, the substrate transfer device 17 can move in the horizontal direction and the vertical direction and can rotate about the vertical axis, and transfers the wafer W between the delivery section 14 and the processing unit 16 using a wafer holding mechanism. I do.

The processing unit 16 performs predetermined substrate processing on the wafer W transferred by the substrate transfer device 17 .

The substrate processing system 1 also includes a control device 4 . Control device 4 is, for example, a computer, and includes control unit 18 and storage unit 19 . The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1 . The control unit 18 controls the operation of the substrate processing system 1 by reading and executing programs stored in the storage unit 19 .

The program may be recorded in a computer-readable storage medium and installed in the storage unit 19 of the control device 4 from the storage medium. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnet optical disks (MO), and memory cards.

In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading/unloading station 2 takes out the wafer W from the carrier C placed on the carrier platform 11, and receives the taken out wafer W. It is placed on the transfer section 14 . The wafer W placed on the transfer section 14 is taken out from the transfer section 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16 .

The wafer W loaded into the processing unit 16 is processed by the processing unit 16, then unloaded from the processing unit 16 by the substrate transport device 17, and placed on the transfer section 14. Then, the processed wafer W placed on the transfer section 14 is returned to the carrier C on the carrier placement section 11 by the substrate transfer device 13 .

<Configuration of processing unit>
Next, the configuration of the processing unit 16 will be described with reference to FIG. FIG. 2 is a schematic diagram showing an example of a specific configuration of the processing unit 16. As shown in FIG. As shown in FIG. 2 , the processing unit 16 includes a chamber 20 , a substrate processing section 30 , a liquid supply section 40 and a collection cup 50 .

The chamber 20 accommodates the substrate processing section 30 , the liquid supply section 40 and the collection cup 50 . An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20 . FFU 21 forms a downflow in chamber 20 .

The substrate processing section 30 includes a holding section 31, a support section 32, and a driving section 33, and performs liquid processing on the placed wafer W. The holding part 31 holds the wafer W horizontally. The column portion 32 is a member extending in the vertical direction, the base end portion of which is rotatably supported by the drive portion 33, and the tip portion of which supports the holding portion 31 horizontally. The drive section 33 rotates the support section 32 around the vertical axis.

The substrate processing section 30 rotates the supporting section 31 supported by the supporting section 32 by rotating the supporting section 32 using the driving section 33, thereby rotating the wafer W held by the supporting section 31. .

A holding member 31a for holding the wafer W from the side surface is provided on the upper surface of the holding section 31 provided in the substrate processing section 30. As shown in FIG. The wafer W is held horizontally by the holding member 31a while being slightly separated from the upper surface of the holding portion 31. As shown in FIG. The wafer W is held by the holder 31 with the surface on which substrate processing is performed directed upward.

The liquid supply unit 40 supplies the processing fluid to the wafer W. The liquid supply unit 40 includes

nozzles

41a and 41b, an arm 42a that horizontally supports the

nozzles

41a and 41b, and a swing/lift mechanism 43a that swings and lifts the arm 42a. The liquid supply unit 40 also includes a nozzle 41c, an arm 42b that horizontally supports the nozzle 41c, and a turning and lifting mechanism 43b that turns and lifts the arm 42b.

The nozzle 41a is connected to an etchant supply section 46a via a valve 44a and a flow rate regulator 45a. Nozzle 41b is connected to additional liquid supply 46b via valve 44b and flow regulator 45b.

The etchant supplied from the etchant supply unit 46a contains hydrofluoric acid (HF) having a predetermined concentration and an additive. The hydrofluoric acid concentration of the etchant is, for example, 5 (wt %) to 50 (wt %).

Moreover, the additive added to the etchant is, for example, methanesulfonic acid (CH ₃ SO ₃ H). The concentration of methanesulfonic acid in the etching liquid according to the embodiment is, for example, 0.01 (wt %) or more and less than 0.1 (wt %).

In the present disclosure, the additive added to the etchant is not limited to methanesulfonic acid, and may be hydrochloric acid (HCl), for example. The concentration of hydrochloric acid in the etchant according to the embodiment is, for example, 5 (wt %) to 30 (wt %).

The additional liquid supplied from the additional liquid supply unit 46b is, for example, hydrochloric acid or SC1 (mixed liquid of ammonia and hydrogen peroxide solution).

The nozzle 41c is connected to the rinse liquid supply section 46c via a valve 44c and a flow rate regulator 45c. The rinse liquid supplied from the rinse liquid supply section 46c is, for example, DIW (DeIonized Water). Note that the rinse liquid according to the embodiment is not limited to DIW.

The etchant supplied from the etchant supply unit 60 is discharged from the nozzle 41a. The additional liquid supplied from the additional liquid supply section 46b is discharged from the nozzle 41b. The rinse liquid supplied from the rinse liquid supply portion 46c is discharged from the nozzle 41c.

The collection cup 50 is arranged so as to surround the holding portion 31 and collects the processing liquid 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 processing liquid collected by the recovery cup 50 is discharged to the outside of the processing unit 16 through the drain port 51 . An exhaust port 52 is formed at the bottom of the collection cup 50 to discharge the gas supplied from the FFU 21 to the outside of the processing unit 16 .

<Details of substrate processing>
Next, the details of the substrate processing for the wafer W in the processing unit 16 will be described with reference to FIGS. 3 to 13. FIG. In substrate processing according to the embodiment, first, a wafer W having a surface structure as shown in FIG. 3 is prepared. FIG. 3 is a schematic diagram showing an example of the state of the surface of the wafer W after preparatory processing according to the embodiment.

As shown in FIG. 3, on the surface of the wafer W, a multilayer film ML and a metal oxide film Z are formed. The multilayer film ML is formed on the surface of the underlying layer F0. The underlying layer F0 is made of, for example, silicon oxide (SiO ₂ ).

The multilayer film ML has, for example, a first layer F1, a second layer F2, and a third layer F3, which are arranged in this order from the surface of the underlying layer F0. The first layer F1 is made of polysilicon, for example. The second layer F2 is made of tungsten, for example. The third layer F3 is made of silicon nitride (SiN), for example.

The metal oxide film Z is formed on the surface of the multilayer film ML (specifically, the surface of the third layer F3). The metal oxide film Z is composed of at least one of zirconium oxide (ZrO ₂ ) and hafnium oxide (HfO ₂ ), and functions as a hard mask. That is, in the present disclosure, the metal oxide film Z is a general term for the zirconium oxide film and the hafnium oxide film.

The metal oxide film Z according to the embodiment is formed, for example, by a method called atomic layer deposition (ALD). Specifically, in this method, a precursor of zirconium oxide or hafnium oxide and water are decomposed in a high-temperature vacuum environment (for example, 400 ° C., <1 kPa) to form ZrO ₂ or HfO ₂ molecular layers one by one, A film is formed by lamination.

Also, as shown in FIG. 3, the multilayer film ML and the metal oxide film Z are dry-etched into a given shape with a high aspect ratio so that part of the surface of the underlying layer F0 is exposed. In addition, in the present disclosure, the configurations of the underlying layer F0 and the multilayer film ML are not limited to the example of FIG. 3 .

Next, the wafer W having the surface structure described so far is carried into the chamber 20 (see FIG. 2) of the processing unit 16 (see FIG. 2) by the substrate transfer device 17 (see FIG. 1). The wafer W is held by the holding member 31a (see FIG. 2) of the substrate processing section 30 (see FIG. 2) with the surface to be processed facing upward.

After that, the control unit 18 (see FIG. 1) controls the driving unit 33 (see FIG. 2) to rotate the holding member 31a together with the wafer W at a given rotation speed.

Then, in the processing unit 16, the metal oxide film Z is etched with an etchant. In such an etching process, the control unit 18 moves the nozzle 41a (see FIG. 2) of the liquid supply unit 40 (see FIG. 2) above the center of the wafer W. As shown in FIG.

After that, the control unit 18 supplies an etchant containing hydrofluoric acid and methanesulfonic acid to the surface of the wafer W by opening the valve 44a (see FIG. 2) for a given time.

Thereby, the control unit 18 can satisfactorily etch only the metal oxide film Z among the plurality of films formed on the surface of the wafer W without residue, as described below.

4 to 7 are diagrams showing SEM observation photographs after the etching treatment test of the zirconium oxide film in the present disclosure. In the etching test of the present disclosure described below, a SEM observation photograph of a test piece in which a 20 (nm) zirconium oxide film or hafnium oxide film was formed on a substrate by the ALD method was etched in a beaker test. showing. Also, the etching test in the present disclosure is performed at a processing temperature of 50 (°C).

FIG. 4 is an SEM observation photograph of the surface of the test piece after etching the zirconium oxide film for 600 (seconds) with an etching solution having a hydrofluoric acid concentration of 13.86 (wt %) and no additives. FIG. 5 shows the surface of the test piece after etching the zirconium oxide film for 600 (seconds) with an etchant having a hydrofluoric acid concentration of 13.85 (wt%) and a methanesulfonic acid concentration of 0.02 (wt%). It is an SEM observation photograph. In the present disclosure, methanesulfonic acid is also referred to as "MSA."

FIG. 6 shows the surface of the test piece after etching the zirconium oxide film for 600 (seconds) with an etching solution having a hydrofluoric acid concentration of 13.80 (wt%) and a methanesulfonic acid concentration of 0.36 (wt%). It is an SEM observation photograph. FIG. 7 shows the surface of the test piece after etching the zirconium oxide film for 600 (seconds) with an etchant having a hydrofluoric acid concentration of 13.82 (wt %) and a methanesulfonic acid concentration of 0.73 (wt %). It is an SEM observation photograph.

As shown in FIG. 4, in the present disclosure, in the etching process using an etching solution to which methanesulfonic acid is not added, many residues and granular residues are present on the surface after the etching process. On the other hand, as shown in FIG. 5, by adding 0.02 (wt %) of methanesulfonic acid to the etchant, the surface after the etching process can be left in a good state without residue or the like.

This is composed of the above-mentioned fluoride by complexing the zirconium fluoride ZrF ₆ ²⁻ generated when a zirconium oxide film is etched with hydrofluoric acid as shown in the following chemical formula (1). It is presumed that this is because re-adhesion of the residue can be suppressed.
ZrF ₆ ²⁻ +CH ₃ SO ₃ H→[Zr(CH ₃ SO ₃ )F ₅ ] ²⁻ +HF (1)

Thus, in the embodiment, the zirconium oxide film can be satisfactorily removed from the wafer W by adding a predetermined amount of methanesulfonic acid to the etchant.

Further, as shown in FIGS. 6 and 7, in the present disclosure, in the etching process using an etching solution to which 0.36 (wt %) or 0.73 (wt %) of methanesulfonic acid is added, after the etching process There are many residues and granular residues on the surface.

That is, in the embodiment, the concentration of methanesulfonic acid in the etchant should be 0.01 (wt%) or more and less than 0.1 (wt%). Thereby, the zirconium oxide film can be removed from the wafer W satisfactorily.

8 to 11 are diagrams showing SEM observation photographs after the etching treatment test of the hafnium oxide film in the present disclosure. FIG. 8 is an SEM observation photograph of the surface of the test piece after the hafnium oxide film was etched for 600 (seconds) with an etchant having a hydrofluoric acid concentration of 41.97 (wt %) and no additive.

FIG. 9 shows the surface of the test piece after etching the hafnium oxide film for 600 (seconds) with an etchant having a hydrofluoric acid concentration of 42.01 (wt%) and a methanesulfonic acid concentration of 0.05 (wt%). It is an SEM observation photograph. FIG. 10 shows the surface of the test piece after etching the hafnium oxide film for 600 (seconds) with an etchant having a hydrofluoric acid concentration of 42.01 (wt%) and a methanesulfonic acid concentration of 0.50 (wt%). It is an SEM observation photograph.

FIG. 11 shows the surface of the test piece after etching the hafnium oxide film for 600 (seconds) with an etching solution having a hydrofluoric acid concentration of 42.01 (wt%) and a methanesulfonic acid concentration of 1.01 (wt%). It is an SEM observation photograph.

As shown in FIG. 8, in the present disclosure, in the etching process using an etching solution to which methanesulfonic acid is not added, many residues and granular residues are present on the surface after the etching process. Further, as shown in FIG. 9, in the present disclosure, in the etching process using an etching solution to which 0.05 (wt%) of methanesulfonic acid is added, a large amount of residue or granular residue is present on the surface after the etching process. .

On the other hand, as shown in FIG. 10, by adding 0.50 (wt %) of methanesulfonic acid to the etchant, the surface after the etching treatment can be left in a good state without residues.

This is composed of the above-mentioned fluoride by complexing the hafnium fluoride HfF ₆ ²⁻ generated when a hafnium oxide film is etched with hydrofluoric acid as shown in the following chemical formula (2). It is presumed that this is because re-adhesion of the residue can be suppressed.
HfF ₆ ²⁻ +CH ₃ SO ₃ H→[Hf(CH ₃ SO ₃ )F ₅ ] ²⁻ +HF (2)

Thus, in the embodiment, the hafnium oxide film can be satisfactorily removed from the wafer W by adding a predetermined amount of methanesulfonic acid to the etchant.

Further, as shown in FIG. 11, in the present disclosure, in the etching process using an etching solution to which 1.01 (wt%) of methanesulfonic acid is added, a large amount of residue and granular residues are present on the surface after the etching process. .

That is, in the embodiment, the concentration of methanesulfonic acid in the etchant should be 0.1 (wt%) or more and less than 1.0 (wt%). Thereby, the hafnium oxide film can be removed from the wafer W satisfactorily.

Also, in the embodiment, the etchant preferably contains hydrofluoric acid. Thereby, the metal oxide film Z on the wafer W can be etched satisfactorily.

Also, in the embodiment, the hydrofluoric acid concentration of the etchant is preferably 5 (wt %) to 50 (wt %). Accordingly, since the metal oxide film Z can be etched at a high etching rate, the metal oxide film Z can be removed from the wafer W efficiently.

Also, in the embodiment, the temperature of the etchant may be room temperature to 60 (° C.). Accordingly, since the metal oxide film Z can be etched at a high etching rate, the metal oxide film Z can be removed from the wafer W efficiently.

Further, in the embodiment, the film thickness of the metal oxide film Z is preferably 5 (nm) or more and less than 20 (nm). Thereby, the metal oxide film Z can be satisfactorily removed without remaining on the wafer W. FIG.

Also, in the embodiment, the metal oxide film Z may be formed on the surface of at least one of the silicon nitride film, the polysilicon film, and the silicon oxide film formed on the wafer W. As a result, the metal oxide film Z can be selectively etched while leaving these underlying films on the wafer W. FIG.

Although the example of FIG. 3 shows the case where a single film of the metal oxide film Z formed on the wafer W is etched, the present disclosure is not limited to this example. For example, according to the technique of the present disclosure, a laminated film of zirconium oxide film/aluminum oxide film/zirconium oxide film (so-called ZAZ structure) formed on the wafer W may be etched.

Further, the lamination film of hafnium oxide film/aluminum oxide film/hafnium oxide film formed on the wafer W may be etched by the technique of the present disclosure. Even in these cases, such laminated films can be removed from the wafer W satisfactorily.

Also, in the above embodiment, an example of using an etchant in which methanesulfonic acid is added to hydrofluoric acid is shown, but the additive added to hydrofluoric acid is not limited to methanesulfonic acid. 12 and 13 are diagrams showing SEM observation photographs after another etching treatment test of the zirconium oxide film in the present disclosure.

Note that FIG. 12 is an SEM observation photograph of the surface of the test piece after etching the zirconium oxide film for 300 (seconds) with an etching solution having a hydrofluoric acid concentration of 50 (wt %) and no additive. FIG. 13 shows the zirconium oxide film after the zirconium oxide film has been etched for 300 (seconds) with an etchant having a hydrofluoric acid concentration of 37.8 (wt %) and a hydrochloric acid concentration of 9.2 (wt %) as an additive. It is an SEM observation photograph of the test piece surface.

As shown in FIG. 12, in the present disclosure, in the etching process using an etchant to which hydrochloric acid is not added, many residues and granular residues are present on the surface after the etching process. On the other hand, as shown in FIG. 13, by adding 9.2 (wt %) of hydrochloric acid to the etchant, the surface after the etching treatment can be left in a state where there are few residues.

This is because when a zirconium oxide film is etched with hydrofluoric acid, hydrochloric acid is added to the etchant to lower the pH of the etchant, thereby promoting ionization of zirconium and efficiently removing the zirconium oxide film. presumed to be for

Thus, in the embodiment, the zirconium oxide film can be satisfactorily removed from the wafer W by adding a predetermined amount of hydrochloric acid to the etchant.

<Modification>
Subsequently, modifications of the substrate processing according to the embodiment will be described with reference to FIGS. 14 to 17. FIG. 14 and 15 are diagrams showing SEM observation photographs after the etching treatment test of the zirconium oxide film in the modified example of the present disclosure.

In FIG. 14, after etching the zirconium oxide film for 300 (seconds) with an etching solution having a hydrofluoric acid concentration of 50 (wt %) and no additive, hydrochloric acid having a concentration of 9.2 (wt %) is added as an additional solution. It is an SEM observation photograph of the surface of the test piece after being supplied to the wafer W for 60 (seconds).

In FIG. 15, after the zirconium oxide film is etched for 300 (seconds) with an etchant having a hydrofluoric acid concentration of 50 (wt %) and no additive, hydrochloric acid having a concentration of 26.0 (wt %) is added as an additional liquid. It is an SEM observation photograph of the surface of the test piece after being supplied to the wafer W for 60 (seconds).

By comparing the examples of FIGS. 14 and 15 with the example of FIG. 12 described above, in the present disclosure, the surface of the wafer W after the etching process is treated with an additional solution of hydrochloric acid to remove residues. , etc., can be reduced.

This is because after the zirconium oxide film is etched with hydrofluoric acid, the pH on the wafer W is lowered by additional treatment with hydrochloric acid, thereby promoting the ionization of zirconium and efficiently removing the zirconium oxide film. guessed.

Thus, in the modified example, the zirconium oxide film can be satisfactorily removed from the wafer W by performing additional processing with hydrochloric acid after the etching processing with hydrofluoric acid.

In addition, although the example using hydrochloric acid as the additional liquid is shown in the above modified example, the additional liquid used for the additional treatment is not limited to hydrochloric acid. 16 and 17 are diagrams showing SEM observation photographs after another etching treatment test of the zirconium oxide film in the modified example of the present disclosure.

In FIG. 16, after etching the zirconium oxide film for 300 (seconds) with an etchant having a hydrofluoric acid concentration of 50 (wt %) and no additive, SC1 was supplied to the wafer W as an additional liquid for 60 (seconds). It is a SEM observation photograph of the surface of the test piece after.

FIG. 17 shows that after etching the zirconium oxide film for 300 (seconds) with an etchant having a hydrofluoric acid concentration of 37.8 (wt %) and a hydrochloric acid concentration of an additive of 9.2 (wt %), It is an SEM observation photograph of the test piece surface after supplying SC1 as an additional liquid to the wafer W for 60 (seconds). In the examples of FIGS. 16 and 17, SC1 has a mixture ratio of ammonia:hydrogen peroxide solution:water of 1:10:10.

By comparing the examples of FIGS. 16 and 17 with the examples of FIGS. 12 and 13 described above, in the present disclosure, the surface after the etching treatment is treated with an additional SC1 solution after the etching treatment. It can be seen that a state with little residue can be achieved. In particular, in the example of FIG. 17, it can be seen that the surface after the etching process is in a good state without any residue or the like.

This is because the reattachment of the residue composed of fluoride ZrF ₆ ^2- can be suppressed by electrostatic repulsion by changing the surface potential of the base film from positive to negative by the additional treatment in SC1. guessed.

Thus, in the modified example, the zirconium oxide film can be satisfactorily removed from the wafer W by performing additional processing in SC1 after the etching processing with hydrofluoric acid.

14 to 17 show examples in which the zirconium oxide film is subjected to additional treatment with hydrochloric acid or SC1, but the present disclosure is not limited to such an example, and the hafnium oxide film is treated with hydrochloric acid. Alternatively, an additional treatment with an additional liquid of SC1 may be performed.

Further, in the embodiments and modifications described so far, examples of etching the metal oxide film Z formed on the multilayer film ML (see FIG. 3) have been described, but the present disclosure is not limited to such examples. .

For example, in the present disclosure, a single-layer metal oxide film formed around the gate of a transistor may be etched. Further, in the present disclosure, among the laminated films such as the ZAZ structure formed over the entire wafer W, only the laminated film formed on the bevel portion may be etched.

Further, in the embodiments and modifications shown so far, an example in which the wafer W is etched by single-wafer processing in the processing unit 16 has been described, but the present disclosure is not limited to such an example, and a plurality of wafers W are collectively processed. The technology of the present disclosure may also be applied to batch processing. As a result, the metal oxide films Z can be satisfactorily removed from the plurality of wafers W. FIG.

<Substrate processing procedure>
Next, a substrate processing procedure according to the embodiment will be described with reference to FIGS. 18 and 19. FIG. FIG. 18 is a flow chart showing the procedure of substrate processing executed by the substrate processing system 1 according to the embodiment.

In the substrate processing according to the embodiment, first, preparation processing is performed (step S101). In this preparatory process, as shown in FIG. 3, a metal oxide film Z is formed on the laminated film ML, and a wafer W is prepared which is dry-etched into a given shape.

Next, the control section 18 controls the processing unit 16 and the like to perform holding processing for holding the wafer W in the holding section 31 (step S102). Then, the control unit 18 controls the liquid supply unit 40 and the like to supply an etchant containing hydrofluoric acid and an additive to the wafer W, and performs an etching process for etching the metal oxide film Z (step S103). .

Next, the control unit 18 controls the liquid supply unit 40 and the like to perform the rinsing process of the wafer W with the rinsing liquid (step S104). Then, the controller 18 controls the processing unit 16 to dry the wafer W (step S105), thus completing a series of substrate processing.

Such a drying process may be performed, for example, by shaking off the surface of the wafer W wet with the rinse liquid as it is, or by substituting the surface of the wafer W wet with the rinse liquid with IPA and then performing the shaking off process. good.

FIG. 19 is a flow chart showing the procedure of substrate processing executed by the substrate processing system 1 according to the modification of the embodiment. In substrate processing according to the modification, first, a preparatory processing is performed (step S201).

Next, the control section 18 controls the processing unit 16 and the like to perform holding processing for holding the wafer W in the holding section 31 (step S202). The processing of steps S201 and S202 is the same as the processing of steps S101 and S102 described above.

Next, the control unit 18 controls the liquid supply unit 40 and the like to supply an etchant containing hydrofluoric acid to the wafer W to perform an etching process for etching the metal oxide film Z (step S203). Incidentally, in the process of step S203, an etching process may be performed with an etching solution containing hydrofluoric acid and an additive.

Next, the control unit 18 controls the liquid supply unit 40 and the like to perform an additional process of supplying additional liquid to the wafer W (step S204). Then, the control unit 18 controls the liquid supply unit 40 and the like to perform the rinsing process of the wafer W with the rinsing liquid (step S205).

Finally, the control unit 18 controls the processing unit 16 to dry the wafer W (step S206), completing a series of substrate processing.

The substrate processing method according to the embodiment includes an etching process (steps S103, S203). In the etching step (steps S103 and S203), an etchant is supplied to a substrate (wafer W) on which at least one of a zirconium oxide film and a hafnium oxide film is formed to remove at least one of the zirconium oxide film and the hafnium oxide film. Etch. Also, in the etching step (steps S103 and S203), an etchant to which methanesulfonic acid is added is supplied to the substrate (wafer W). Thereby, the metal oxide film Z can be removed from the wafer W satisfactorily.

Further, in the substrate processing method according to the embodiment, the zirconium oxide film is a single layer film or a laminated film of zirconium oxide film/aluminum oxide film/zirconium oxide film. As a result, the single layer film or laminated film of the zirconium oxide film can be removed from the wafer W satisfactorily.

Further, in the substrate processing method according to the embodiment, the hafnium oxide film is a single layer film or a laminated film of hafnium oxide film/aluminum oxide film/hafnium oxide film. As a result, the single-layered hafnium oxide film or laminated film of the hafnium oxide film can be removed from the wafer W satisfactorily.

Further, in the substrate processing method according to the embodiment, at least one of the zirconium oxide film and the hafnium oxide film is at least one of a silicon nitride film, a polysilicon film and a silicon oxide film formed on the substrate (wafer W). formed on the surface of As a result, the metal oxide film Z can be selectively etched while leaving these underlying films on the wafer W. FIG.

Further, in the substrate processing method according to the embodiment, the film thickness of at least one of the zirconium oxide film and the hafnium oxide film is 5 (nm) or more and less than 20 (nm). Thereby, the metal oxide film Z can be satisfactorily removed without remaining on the wafer W. FIG.

Also, in the substrate processing method according to the embodiment, the etchant contains hydrofluoric acid. Thereby, the metal oxide film Z on the wafer W can be etched satisfactorily.

Also, in the substrate processing method according to the embodiment, the hydrofluoric acid concentration of the etching liquid is 5 (wt %) to 50 (wt %). Thereby, the metal oxide film Z can be removed from the wafer W efficiently.

Also, in the substrate processing method according to the embodiment, the temperature of the etchant is room temperature to 60 (°C). Thereby, the metal oxide film Z can be removed from the wafer W efficiently.

Further, in the substrate processing method according to the embodiment, the concentration of methanesulfonic acid in the etchant for etching the zirconium oxide film is 0.01 (wt%) or more and less than 0.1 (wt%). Thereby, the zirconium oxide film can be removed from the wafer W satisfactorily.

Further, in the substrate processing method according to the embodiment, the concentration of methanesulfonic acid in the etchant for etching the hafnium oxide film is 0.1 (wt%) or more and less than 1.0 (wt%). Thereby, the hafnium oxide film can be removed from the wafer W satisfactorily.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the gist thereof.

The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. Indeed, the above-described embodiments may be embodied in many different forms. Also, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

W Wafer (an example of a substrate)
REFERENCE SIGNS LIST 1 substrate processing system 16 processing unit 18 control section 31 holding section 40 liquid supply section Z metal oxide film (an example of a zirconium oxide film and a hafnium oxide film)

Claims

an etching step of supplying an etchant to a substrate on which at least one of a zirconium oxide film and a hafnium oxide film is formed to etch at least one of the zirconium oxide film and the hafnium oxide film;
The substrate processing method, wherein the etching step supplies the etchant to which methanesulfonic acid is added to the substrate.
2. The substrate processing method according to claim 1, wherein the zirconium oxide film is a single layer film or a laminated film of zirconium oxide film/aluminum oxide film/zirconium oxide film.
3. The substrate processing method according to claim 1, wherein the hafnium oxide film is a single layer film or a laminated film of hafnium oxide film/aluminum oxide film/hafnium oxide film.
At least one of said zirconium oxide film and said hafnium oxide film is formed on the surface of at least one of a silicon nitride film, a polysilicon film and a silicon oxide film formed on said substrate. The substrate processing method according to any one of the above.
5. The substrate processing method according to claim 1, wherein at least one of the zirconium oxide film and the hafnium oxide film has a thickness of 5 (nm) or more and less than 20 (nm).
The substrate processing method according to any one of claims 1 to 5, wherein the etchant contains hydrofluoric acid.
7. The substrate processing method according to claim 6, wherein the etchant has a hydrofluoric acid concentration of 5 (wt %) to 50 (wt %).
8. The substrate processing method according to claim 6, wherein the temperature of said etchant is room temperature to 60 (° C.).
The substrate according to any one of claims 1 to 8, wherein the etchant for etching the zirconium oxide film has a methanesulfonic acid concentration of 0.01 (wt%) or more and less than 0.1 (wt%). Processing method.
The substrate according to any one of claims 1 to 8, wherein the etchant for etching the hafnium oxide film has a methanesulfonic acid concentration of 0.1 (wt%) or more and less than 1.0 (wt%). Processing method.