Substrate processing method and substrate processing apparatus

Abstract

This substrate processing method includes: preparing a substrate having an oxide film containing oxygen and a non-oxide film containing substantially no oxygen in different regions of a surface of the substrate; modifying a surface of the oxide film with modification gas in order to etch the surface of the oxide film with etching gas; selectively forming an etching protective film on a surface of the non-oxide film with respect to the surface of the oxide film modified with the modification gas; and etching, with the etching gas, the surface of the oxide film modified with the modification gas while protecting the surface of the non-oxide film from the etching gas with the etching protective film.

Description

Substrate processing method and substrate processing apparatus

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

[0002] The atomic layer etching (ALE) described in Patent Document 1 is a method of etching a surface of a silicon oxide film with plasma-generated CF ４ The surface of the modified silicon oxide film is then treated with plasma H ２ This is repeated alternately.

[0003] Japanese Patent Application Publication No. 2019-204950

[0004] One embodiment of the present disclosure provides a technique for selectively etching one portion of a substrate surface while suppressing damage to another portion of the substrate surface.

[0005] A substrate processing method according to one embodiment of the present disclosure includes: preparing a substrate having an oxide film containing oxygen and a non-oxide film substantially free of oxygen in different surface regions; modifying the surface of the oxide film with a modifying gas so as to etch the surface of the oxide film with an etching gas; selectively forming an etching protection film on the surface of the non-oxide film relative to the surface of the oxide film modified with the modifying gas; and etching the surface of the oxide film modified with the modifying gas with the etching gas while protecting the surface of the non-oxide film from the etching gas with the etching protection film.

[0006] According to an embodiment of the present disclosure, when a portion of a substrate surface is selectively etched, damage to another portion of the substrate surface can be suppressed.

[0007] Fig. 1 is a flowchart showing a substrate processing method according to an embodiment. Fig. 2 is a flowchart showing an example of S103 in Fig. 1. Fig. 3 is a flowchart showing an example of S107 in Fig. 1. Fig. 4 is a cross-sectional view showing a substrate processing method according to an embodiment. Fig. 5 is a plan view showing a substrate processing apparatus according to an embodiment. Fig. 6 is a cross-sectional view showing an example of a first processing unit.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or similar components are denoted by the same reference numerals, and their description may be omitted. In the specification, the numerical range "to" means that the numerical values ​​before and after it are included as the lower and upper limits. The numerical range includes the range rounded up or down. In this specification, the semiconductor element is Si or Ge.

[0009] First, a substrate processing method according to one embodiment will be described with reference to Figures 1 to 4. The substrate processing method includes, for example, steps S101 to S108 shown in Figure 1. Note that the substrate processing method may include steps S101 to S106, and does not necessarily include steps S107 to S108. Furthermore, the substrate processing method may include steps other than steps S101 to S108 shown in Figure 1.

[0010] Step S101 includes preparing a substrate W (see, for example, FIG. 4). The substrate W has an oxide film W1 containing oxygen and a non-oxide film W2 containing substantially no oxygen in different regions of its surface. The substrate W may be cleaned in advance so that both the oxide film W1 and the non-oxide film W2 are exposed in different regions of the surface of the substrate W. In this embodiment, the surface of the substrate W is flat, but may also be uneven. It is preferable that both the oxide film W1 and the non-oxide film W2 are substantially free of boron (B). "Substantially free of B" means that the B content is 0 at % to 5 at %.

[0011] The oxide film W1 contains, for example, a compound of a semiconductor element and oxygen, or a compound of a metal and oxygen. The oxide film W1 preferably has an oxygen content of 20 at% to 60 at%. The oxide film W1 is not particularly limited, but may be, for example, a SiO film, a TiO film, a SnO film, a WO film, or a HfO film. Here, the SiO film refers to a film containing silicon (Si) and oxygen (O). The atomic ratio of Si to O in the SiO film is not limited to 1:2. Films other than SiO films, such as TiO films, SnO films, WO films, and HfO films, also contain the respective elements and are not limited to stoichiometric ratios.

[0012] The non-oxide film W2 contains, for example, only a semiconductor element, a compound of a semiconductor element and nitrogen, only a metal, or a compound of a metal and nitrogen. The non-oxide film W2 preferably has an oxygen content of 0 at % to 10 at %. The non-oxide film W2 is not particularly limited, but may be, for example, a Si film, a SiN film, or a SiGe film. When the non-oxide film W2 is a semiconductor film, the semiconductor film may be any of an amorphous film, a polycrystalline film, and a single-crystalline film.

[0013] The oxide film W1 and the non-oxide film W2 are formed on an underlying substrate (not shown). The underlying substrate is a silicon wafer or a compound semiconductor wafer. The compound semiconductor wafer is, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer. The underlying substrate may be a glass substrate. A functional film (not shown) may be formed between the oxide film W1 or the non-oxide film W2 and the underlying substrate (not shown). The oxide film W1 may be formed by naturally oxidizing a film (e.g., a metal film or a semiconductor film) directly below the oxide film W1 due to contact with the atmosphere. The oxide film W1 may be formed by oxidizing a film (e.g., a metal film or a semiconductor film) directly below the oxide film W1 due to reaction with a reactive gas or the like.

[0014] Step S102 includes modifying the surface of the oxide film W1 with a modifying gas to selectively form an etching protection film WB on the surface of the non-oxide film W2 in step S103 and to etch the surface of the oxide film W1 with an etching gas in step S105 (see FIG. 4). The modifying gas selectively modifies the surface of the oxide film W1 relative to the surface of the non-oxide film W2. The surface of the non-oxide film W2 is hardly modified. A modified film WA is formed on the surface of the oxide film W1 by reaction with or adsorption of the modifying gas.

[0015] The modified film WA inhibits the formation of the etching protection film WB in step S103 and is removed by the etching gas in step S105. The modified film WA may be removed by the etching gas in step S107c. A film that has only one of the properties of (1) inhibiting the formation of the etching protection film WB in step S103 and (2) being removed by the etching gas in step S105 is not a modified film WA of the present disclosure.

[0016] The modifying gas is not particularly limited, but may contain, for example, boron, and modify the surface of the oxide film W1 into a boron oxide film. The boron oxide film is an example of the modified film WA. The boron contained in the modifying gas removes oxygen from the oxide film W1, thereby replacing at least a portion of the oxide film W1 with a boron oxide film. At this time, the semiconductor element or metal element contained in the oxide film W1 becomes a volatile compound and is desorbed from the surface of the oxide film W1. In this case, the modifying gas is BCl ３ , BBr ３ , B.I. ３ , B(CH ３ ) ３ , B ２ H ６ , B.F. ３ , C ９ H ２４ BN ３ , C ３ H ９ B, C ６ H １５ B and B ３ N ３ H ６ It is preferable to include at least one of the following.

[0017] The oxide film W1 is a TiO film, and the modifying gas is BCl ３ In the case of a gas, a reforming reaction represented by the following reaction formula (1) proceeds: (1) TiO ２ +4 / 3BC1 ３ (g) → 2 / 3B ２ O ３ + TiCl ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (1) is −27.0 kcal / mol at 100° C.

[0018] The oxide film W1 is a SiO film, and the modifying gas is BCl ３ In the case of gas, the reforming reaction represented by the following reaction formula (2) proceeds: (2) SiO ２ +4 / 3BC1 ３ (g) → 2 / 3B ２ O ３ +SiCl ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (2) is −9.8 kcal / mol at 100° C.

[0019] The oxide film W1 is a SnO film, and the modifying gas is BCl ３ In the case of a gas, a reforming reaction represented by the following reaction formula (3) proceeds: (3) SnO ２ +4 / 3BC1 ３ (g) → 2 / 3B ２ O ３ + SnCl ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (3) is −46.2 kcal / mol at 100° C.

[0020] The oxide film W1 is a WO film, and the modifying gas is BCl ３ When the WO gas is used, the reforming reaction represented by the following reaction formula (4) proceeds: ３ +2BC1 ３ (g) → B ２ O ３ +WC1 ６ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (4) is −13.3 kcal / mol at 100° C.

[0021] The oxide film W1 is a HfO film, and the modifying gas is BCl ３ In the case of HfO gas, the reforming reaction represented by the following reaction formula (5) proceeds: ２ +4 / 3BC1 ３ (g) → 2 / 3B ２ O ３ + HfCl ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (5) is −16.4 kcal / mol at 100° C.

[0022] The oxide film W1 is a SnO film, and the modifying gas is B(CH ３ ) ３ In the case of a gas, a reforming reaction represented by the following reaction formula (6) proceeds: (6) SnO ２ +4 / 3B (CH ３ ) ３ (g) → 2 / 3B ２ O ３ + Sn(CH ３ ) ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (6) is −28.2 kcal / mol at 100° C.

[0023] The oxide film W1 is a SnO film, and the modifying gas is B (C ２ H ５ ) ３ In the case of a gas, a reforming reaction represented by the following reaction formula (7) proceeds: (7) SnO ２ +4 / 3B (C ２ H ５ ) ３ (g) → 2 / 3B ２ O ３ + Sn(C ２ H ５ ) ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (7) is −24.5 kcal / mol at 100° C.

[0024] The oxide film W1 is a SnO film, and the modifying gas is BBr ３ In the case of a gas, a reforming reaction represented by the following reaction formula (8) proceeds: (8) SnO ２ +4 / 3BBr ３ (g) → 2 / 3B ２ O ３ + SnBr ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (8) is −72.1 kcal / mol at 100° C.

[0025] The oxide film W1 is a SnO film, and the reforming gas is BI ３ In the case of a gas, a reforming reaction represented by the following reaction formula (9) proceeds: (9) SnO ２ +4 / 3BI３ (g) → 2 / 3B ２ O ３ + SnI ４ (g) The change in Gibbs energy in the reforming reaction represented by the above reaction formula (9) is −113.4 kcal / mol at 100° C.

[0026] The more negative the change in Gibbs energy is and the larger its absolute value, the more likely the reforming reaction will proceed. To promote the reforming, the reformed gas may be converted into plasma. Note that the above-mentioned values ​​of the change in Gibbs energy are values ​​when the reformed gas is not converted into plasma.

[0027] In step S102, it is preferable to control the temperature of the substrate W to 100° C. or higher in order to promote the modification reaction of the oxide film W1. If the temperature of the substrate W is 100° C. or higher, the modification reaction described above is likely to proceed. The temperature of the substrate W is preferably 200° C. or higher. The temperature of the substrate W is preferably 800° C. or lower.

[0028] Step S103 includes selectively forming an etching protection film WB on the surface of the non-oxide film W2 relative to the surface of the oxide film W1 (the surface of the modified film WA) modified in step S102 (see FIG. 4). Step S103 includes supplying a source gas containing a desired element X and a reactive gas that reacts with an adsorbate of the source gas to the substrate W. The source gas and the reactive gas are supplied alternately or simultaneously. In this case, the etching protection film WB contains the element X.

[0029] 2, step S103 includes, for example, steps S103a to S103e. Note that step S103 may include at least steps S103a, S103c, and S103e, and does not necessarily include steps S103b and S103d. Steps S103a to S103e will be described below.

[0030] Step S103a includes supplying a source gas to the substrate W. The source gas preferably contains a compound of an element X and a halogen. The halogen is fluorine, chlorine, bromine, or iodine. The element X is not particularly limited, but is preferably a metal element, more preferably a transition metal element. The element X is, for example, Ti, W, V, Al, Mo, Sn, Hf, Ta, Nb, Zr, In, Ga, or Sb. A specific example of the source gas is TiCl. ４ , WCl ６ , W.F. ６ , VCl ４ , AlCl ３ , MoCl ５ , SnCl ４ , HfCl ４ , TaCl ５ , NbCl ５ , ZrCl ４ , InCl ３ , GaCl ３ or SbCl ３ The element X may be a semiconductor element, specifically Si or Ge. The source gas is a silicon halide gas or a germanium halide gas. Specific examples of silicon halide gas include SiCl ４ , SiHCl ３ , SiH ２ Cl ２ , SiH ３ Cl, Si ２ Cl ６、 Si ２ HCl ５ , Si ２ Cl ３ CH ３ , SiCl ３ CCl ３ , SiCl ３ CH ３ , or SiH ２ I ２ Specific examples of germanium halide gas include GeCl ４ The source gas may be supplied together with a dilution gas, such as Ar or N ２ is.

[0031] The source gas may be a hydrogenated gas or an organic compound gas. The hydrogenated gas or the organic compound gas contains a metal or a semiconductor element. Examples of the hydrogenated gas include SiH ４ , Si ２ H ６ , H ２ Se, GeH ４ , Ge ２ H ６ , H ２ Te, SbH ３ , or SnH ４ Examples of organic compound gases include Al(CH ３ ) ３ , Ti[N(CH ３ ) ２ ] ４ , Co(C ５ H ５ ) ２ , Ru(C ５ H ５ ) ２ , Ga(CH ３ ) ３ , In(CH ３ ) ３ , Sn(C ２ H ５ ) ４ , Sn(i-C ３ H ７ ) ４ , Mg(C ５ H ５ ) ２ , or Si(CH ３ ) ４ Examples include:

[0032] Step S103b includes supplying a purge gas to the substrate W. The purge gas purges excess source gas that has not been adsorbed onto the substrate W in step S103a. The purge gas may be, for example, a rare gas such as Ar gas or N ２ A gas is used.

[0033] Step S103c includes supplying a reactive gas to the substrate W. The reactive gas reacts with an element X contained in the adsorbate of the source gas to form an etching protective film WB. The etching protective film WB contains the element X. Examples of the reactive gas include an oxygen-containing gas, a nitrogen-containing gas, and a hydrogen-containing gas. The oxygen-containing gas contains oxygen and forms an oxide film of the element X. The oxygen-containing gas is, for example, O ２ , O ３ , CO ２ , N ２ O, NO, or H ２ The nitrogen-containing gas contains nitrogen and forms a nitride film of element X. The nitrogen-containing gas is, for example, NH ３ , or N ２ H ４ The hydrogen-containing gas contains hydrogen and forms a film (for example, a metal film or a semiconductor film) containing element X as a main component. ２ , or H ２ The reactive gas may be supplied together with a diluent gas, such as Ar or N. ２ Includes.

[0034] Step S103c may include converting the reactive gas into plasma, or may include supplying the plasmatized reactive gas to the substrate W. Converting the reactive gas into plasma can promote the formation of the etching protection film WB.

[0035] The reactive gas may be supplied not only in step S103c but also in all of steps S103a to S103d. However, the reactive gas is turned into plasma only in step S103c. This is because the reactive gas becomes more likely to react with adsorbates of the source gas on the substrate W when turned into plasma.

[0036] Step S103c uses O as a reactive gas. ３ may include supplying the gas to the substrate W without converting it into plasma.

[0037] Step S103d includes supplying a purge gas to the substrate W. The purge gas purges excess reactive gas that did not react with the substrate W in step S103c. The purge gas may be, for example, a rare gas such as Ar gas or N ２ A gas is used.

[0038] Step S103e includes checking whether the fourth cycle has been performed N times (N is an integer equal to or greater than 1). The fourth cycle includes steps S103a to S103d. N may be an integer equal to or greater than 2, and the fourth cycle may be repeatedly performed multiple times. The thickness of the etching protection film WB can be increased.

[0039] If the fourth cycle has been performed less than N times (step S103e, NO), the thickness of the etching protection film WB is less than the target value, so the fourth cycle is performed again. N is preferably 10 or more, more preferably 20 or more. N is preferably 100 or less. The target thickness of the etching protection film WB is preferably 1 nm or more, more preferably 5 nm or more.

[0040] On the other hand, if the number of times the fourth cycle has been performed reaches N (step S103e, YES), the film thickness of the etching protection film WB has reached the target value, and therefore the current process ends.

[0041] 2 is an atomic layer deposition (ALD) method, but may be a chemical vapor deposition (CVD) method. In the ALD method, a source gas (step S103a) and a reactant gas (step S103c) are alternately supplied. In the CVD method, the source gas and the reactant gas are simultaneously supplied.

[0042] To prevent the formation of the etching protection film WB on the surface of the boron oxide film, it is important that the adsorption of the source gas to the boron oxide film is weak, and as a result, the adsorbed material of the source gas is desorbed on the surface of the boron oxide film without advancing the film formation reaction (formation of the etching protection film WB). Alternatively, it is important that the source gas is not adsorbed on the surface of the boron oxide film, or that dissociation of the source gas is unlikely to occur on the surface of the boron oxide film. If dissociation of the source gas occurs, the substrate processing reaction is likely to proceed.

[0043] Since the boron oxide film contains boron, it is thought that the source gas is not adsorbed to the surface of the boron oxide film, or is only weakly adsorbed, or the source gas is unlikely to dissociate, and as a result, the formation of the etching protection film WB is inhibited on the surface of the boron oxide film.

[0044] On the other hand, since the non-oxide film W2 does not substantially contain boron, it is considered that the source gas is strongly adsorbed to the surface of the non-oxide film W2 or that the source gas is easily dissociated, and as a result, it is considered that the formation of the etching protection film WB proceeds on the surface of the non-oxide film W2.

[0045] The source gas is preferably a halide. ４ , Si ２ Cl ６ Gases containing halogens such as Si ２ H ６ and hydrogenation gases such as Ti[N(CH ３ ) ２ ] ４ Compared to organometallic gases such as HCl, HCl, HClO, HClCl, HClO ...

[0046] However, the source gas may be a hydrogenation gas or an organic compound gas. Even if the source gas is a hydrogenation gas or an organic compound gas, it is believed that the formation of the etching protection film WB is difficult on the surface of the boron oxide film. This is because the incubation time is longer on the surface of the boron oxide film than on the surface of the non-oxide film W2. The incubation time refers to the time from the start of the film formation process (e.g., the start of supplying the source gas or the reactive gas) to the actual start of film formation. The thickness of the etching protection film WB is set so as to prevent damage to the non-oxide film W2 when etching the boron oxide film in the subsequent etching step (step S105, step S107c). The thickness of the etching protection film WB may be approximately 1 nm as long as the non-oxide film W2 is not exposed due to pinholes or the like when etching the boron oxide film. If the thickness of the etching protection film WB is approximately 1 nm, the hydrogenation gas and the organic compound gas can selectively form the etching protection film WB on the non-oxide film W2 due to the difference in incubation time.

[0047] In the plasma CVD method, in which both the source gas and the reactive gas are converted into plasma, activated species such as ions or radicals are generated by dissociation of the source gas. The activated species generated from the source gas are highly reactive, and it is thought that the substrate processing reaction is likely to proceed not only on the surface of the non-oxide film W2 but also on the surface of the boron oxide film, making it difficult to selectively form the etching protection film WB on the non-oxide film W2. Therefore, it is preferable not to convert the source gas into plasma, and it is important to use the thermal ALD method, the plasma ALD method, or the thermal CVD method.

[0048] In the above steps S103a to S103d, the temperature of the substrate W may be controlled to 100°C or higher to promote desorption of the source gas from the surface of the boron oxide film. If the temperature of the substrate W is lower than 100°C, the source gas will not be sufficiently desorbed from the surface of the boron oxide film and will be physically adsorbed, resulting in the formation of an etching protection film WB on the surface of the boron oxide film as well. The temperature of the substrate W is preferably 200°C or higher. The temperature of the substrate W is preferably 800°C or lower.

[0049] Step S104 includes checking whether the first cycle has been performed K times (K is an integer equal to or greater than 1). The first cycle includes supplying a modifying gas (step S102) and forming an etching protection film WB (step S103). K may be an integer equal to or greater than 2, and the first cycle may be repeatedly performed multiple times. In step S103, if damage to the modified film WA by plasma or the like progresses and the surface of the oxide film W1 is exposed before the thickness of the etching protection film WB reaches a target value, it is effective to repeatedly perform the first cycle.

[0050] If the number of times the first cycle has been performed is less than K (step S104, NO), the thickness of the etching protection film WB is less than the target value, so the first cycle is performed again. K is preferably 1 or more, and more preferably 2 or more. K is preferably 10 or less. The target value of the thickness of the etching protection film WB is preferably 1 nm or more, and more preferably 5 nm or more.

[0051] On the other hand, if the number of times the first cycle has been performed reaches K (step S104, YES), the film thickness of the etching protection film WB has reached the target value, so step S105 is performed. Note that if K is an integer of 2 or greater, that is, if the first cycle is repeatedly performed, the etching protection film WB is preferably a non-oxide film that does not substantially contain oxygen. The non-oxide film preferably has an oxygen content of 0 at% to 10 at%. If the etching protection film WB is a non-oxide film, the modifying gas does not modify the etching protection film WB in step S102 from the second time onwards.

[0052] Step S105 involves etching the modified film WA with an etching gas while protecting the surface of the non-oxide film W2 from the etching gas with an etching protection film WB (see FIG. 4). The etching gas is not particularly limited, but may be, for example, a rare gas plasma. The rare gas plasma sputters the modified film WA and promotes its volatilization. As a result, etching of the modified film WA progresses. The rare gas may include He, Ne, Ar, Kr, or Xe.

[0053] The etching gas is not limited to rare gases.２ , O ２ , COS, N.H. ３ , S.O. ２ , CO ２ , CO, CH ４ , NO ２ , NO or N ２ When the modified film WA is a boron oxide film, the etching gas may contain Cl ２ , F ２ , HF, XeF ２ , ClF ３ , BrF ３ , HCl, Br ２ , HBr, I ２ , H.I., N.F. ３ , SOCl ２ , S.O. ２ Cl ２ , or SF ６ When the modified film WA is a boron oxide film, the etching gas may contain CF ４ , C.H. ３ F, CHF ３ , C ４ F ６ , C ４ F ８ , C.H. ３ Cl, COCl ２ , or CH ３ The etching gas may contain Br. These etching gases may be turned into plasma.

[0054] The etching gas may etch not only the modified film WA but also the etching protection film WB. Even in the latter case, it is sufficient that the etching protection film WB remains, and the surface of the non-oxide film W2 is not exposed. It is sufficient that the surface of the non-oxide film W2 is not damaged by the etching gas.

[0055] ALE is a method in which the formation of a modified film by supplying a modifying gas and the removal of the modified film by supplying an etching gas are alternately repeated. For example, if the modifying gas selectively reacts with or adsorbs onto the surface of the oxide film W1 to form a modified film, but does little to modify the surface of the non-oxide film W2, the oxide film W1 can be selectively etched. However, if the surface of the non-oxide film W2 is exposed, the non-oxide film W2 may be damaged by the etching gas. Furthermore, if the etching gas is a rare gas plasma, ions generated in the plasma may collide with the non-oxide film W2, potentially damaging the non-oxide film W2 through sputtering.

[0056] When the oxide film W1 to be etched contains a transition metal element, such as a high-k film, a high substrate temperature or high ion energy is required to proceed with etching of the oxide film W1. Therefore, if the surface of the non-oxide film W2 is exposed, it is considered that it is more difficult to prevent damage to the non-oxide film W2.

[0057] According to this embodiment, the surface of the oxide film W1 is modified to prevent the formation of the etching protection film WB on the surface of the oxide film W1, and the etching protection film WB is selectively formed on the surface of the non-oxide film W2. Thereafter, the modified film WA is removed while protecting the surface of the non-oxide film W2 with the etching protection film WB, thereby suppressing damage to the non-oxide film W2.

[0058] Step S106 includes checking whether the second cycle has been performed L times (L is an integer equal to or greater than 1). The second cycle includes supplying a modifying gas (step S102), forming an etching protection film WB (step S103), and supplying an etching gas (step S105). L may be an integer equal to or greater than 2, and the second cycle may be repeatedly performed multiple times. When the thickness of the etching protection film WB does not remain equal to or greater than the set value at the end of step S105, it is effective to repeatedly perform the second cycle.

[0059] If the number of times the second cycle has been performed is less than L (step S106, NO), the etching amount of the oxide film W1 is less than the target value and the film thickness of the etching protection film WB is less than the set value (e.g., less than 1 nm), so the second cycle is performed again. L is preferably 10 or more, more preferably 20 or more. L is preferably 100 or less.

[0060] On the other hand, if the number of times the second cycle has been performed reaches L (step S106, YES), the etching amount of the oxide film W1 is less than the target value, and the thickness of the etching protection film WB is equal to or greater than a set value (e.g., 1 nm or more), step S107 is performed. If the number of times the second cycle has been performed reaches L (step S106, YES), and the etching amount of the oxide film W1 has reached the target value, steps S107 and S108 do not need to be performed.

[0061] When L is an integer of 2 or more, that is, when the second cycle is repeated, the etching protection film WB is preferably a non-oxide film that does not substantially contain oxygen. The non-oxide film preferably has an oxygen content of 0 at % to 10 at %. If the etching protection film WB is a non-oxide film, the modifying gas does not modify the etching protection film WB in step S102 from the second time onwards.

[0062] 3, step S107 includes, for example, steps S107a to S107e. Note that step S107 may include at least steps S107a, S107c, and S107e, and does not necessarily include steps S107b and S107d. Steps S107a to S107e will be described below.

[0063] Step S107a includes supplying a modifying gas to the substrate W. The modifying gas is preferably the same as the modifying gas used in step S102. The modifying gas is not particularly limited, but may contain, for example, boron, and modify the surface of the oxide film W1 into a boron oxide film. In this case, the modifying gas may be BCl ３ , BBr ３ , B.I. ３ , B(CH ３ ) ３, B ２ H ６ , B.F. ３ , C ９ H ２４ BN ３ , C ３ H ９ B, C ６ H １５ B and B ３ N ３ H ６ It is preferable to include at least one of the following.

[0064] Step S107b includes supplying a purge gas to the substrate W. The purge gas purges excess modifying gas that was not used in the modification of the substrate W in step S107a. The purge gas may be, for example, a rare gas such as Ar gas or N ２ A gas is used.

[0065] Step S107c includes supplying an etching gas to the substrate W. The etching gas is preferably the same as the etching gas used in step S105. Step S107c includes etching the modified film WA with the etching gas while protecting the surface of the non-oxide film W2 from the etching gas with an etching protection film WB (see FIG. 4). The etching gas is not particularly limited, but may be, for example, a rare gas plasma. The rare gas plasma sputters the modified film WA and promotes its volatilization. As a result, etching of the modified film WA progresses. The rare gas includes He, Ne, Ar, Kr, or Xe.

[0066] The etching gas is not limited to a rare gas. ２ , O ２ , COS, N.H. ３ , S.O. ２ , CO ２ , CO, CH ４ , NO ２ , NO or N ２ When the modified film WA is a boron oxide film, the etching gas may contain Cl ２ , F ２ , HF, XeF ２ , ClF ３ , BrF ３ , HCl, Br２ , HBr, I ２ , H.I., N.F. ３ , SOCl ２ , S.O. ２ Cl ２ , or SF ６ When the modified film WA is a boron oxide film, the etching gas may contain CF ４ , C.H. ３ F, CHF ３ , C ４ F ６ , C ４ F ８ , C.H. ３ Cl, COCl ２ , or CH ３ The etching gas may contain Br. These etching gases may be turned into plasma.

[0067] Step S107d includes supplying a purge gas to the substrate W. The purge gas purges excess etching gas that did not react with the substrate W in step S107c. The purge gas may be, for example, a rare gas such as Ar gas or N ２ A gas is used.

[0068] Step S107e includes checking whether the fifth cycle has been performed J times (J is an integer equal to or greater than 1). The fifth cycle includes steps S107a to S107d. J may be an integer equal to or greater than 2, and the fifth cycle may be repeatedly performed multiple times. This can increase the etching amount of the oxide film W1.

[0069] If the thickness of the etching protection film WB remains, for example, 1 nm or more, and the fifth cycle has been performed less than J times (step S107e, NO), the etching amount of the oxide film W1 is less than the target value, so the fifth cycle is performed again. J is preferably 10 or more, more preferably 20 or more. J is preferably 100 or less.

[0070] On the other hand, if the fifth cycle has been performed J times (YES in step S107e), the current process ends. The fact that the fifth cycle has been performed J times may include (1) the etching amount of the oxide film W1 reaching the target value, or (2) the etching amount of the oxide film W1 not reaching the target value but the thickness of the etching protection film WB becoming less than 1 nm.

[0071] Step S108 includes checking whether the third cycle has been performed M times (M is an integer equal to or greater than 1). The third cycle includes supplying a modifying gas (step S102), forming an etching protection film WB (step S103), and supplying an etching gas (step S105), and then supplying a modifying gas (step S107a) and an etching gas (step S107c) without forming the etching protection film WB in between. M may be an integer equal to or greater than 2, and the third cycle may be repeated multiple times. This can increase the amount of etching of the oxide film W1.

[0072] If the third cycle has been performed less than M times (step S108, NO), the etching amount of the oxide film W1 is less than the target value, so the third cycle is performed again. M is preferably 1 or more, more preferably 2 or more. M is preferably 10 or less.

[0073] On the other hand, if the number of times the third cycle has been performed reaches M (step S108, YES), the etching amount of the oxide film W1 has reached the target value, and the current process is terminated. Note that if M is an integer of 2 or greater, that is, if the third cycle is repeatedly performed, the etching protection film WB is preferably a non-oxide film that does not substantially contain oxygen. The non-oxide film preferably has an oxygen content of 0 at% to 10 at%. If the etching protection film WB is a non-oxide film, the modifying gas does not modify the etching protection film WB in step S102 from the second time onwards.

[0074] As described above, the substrate processing method of this embodiment includes steps S102, S103, and S105. Step S102 includes modifying the surface of the oxide film W1 with a modifying gas so that the surface of the oxide film W1 is etched with an etching gas in step S105. Step S103 includes selectively forming an etching protection film WB on the surface of the non-oxide film W2 relative to the surface of the oxide film W1 modified in step S102. Step S105 includes etching the surface of the oxide film W1 modified with the modifying gas with the etching gas while protecting the surface of the non-oxide film W2 from the etching gas with the etching protection film WB.

[0075] According to this embodiment, by utilizing the film formation inhibiting property of the surface of the oxide film W1 modified in step S102, an etching protection film WB can be selectively formed on the surface of the non-oxide film W2 relative to the surface of the oxide film W1 in step S103. As a result, the etching protection film WB can protect the surface of the non-oxide film W2 from the etching gas in step S105. Therefore, when selectively etching one portion of the substrate surface (the surface of the oxide film W1), damage to another portion of the substrate surface (the surface of the non-oxide film W2) can be suppressed.

[0076] The modifying gas in this embodiment contains boron and modifies the surface of the oxide film W1 into a boron oxide film, but the technology of the present disclosure is not limited to the above embodiment. For example, the modifying gas may contain a halogen and adsorb the halogen to the surface of the oxide film W1. The modifying gas selectively modifies the surface of the oxide film W1 relative to the surface of the non-oxide film W2. The surface of the non-oxide film W2 hardly adsorbs the halogen.

[0077] The modifying gas may contain a halogen without substantially containing carbon, and the halogen may be adsorbed on the surface of the oxide film W1. In this case, the modifying gas may contain Cl ２ , F ２ , HF, XeF ２ , ClF ３ , BrF ３ , HCl, Br ２ , HBr, I ２ , H.I., N.F. ３ , SOCl２ , S.O. ２ Cl ２ , and S.F. ６ It is preferable to include at least one of the following.

[0078] The modifying gas may contain a compound of carbon and halogen, and the halogen may be adsorbed on the surface of the oxide film W1. In this case, the modifying gas may be CF ４ , C.H. ３ F, CHF ３ , C ４ F ６ , C ４ F ８ , C.H. ３ Cl, COCl ２ , and C.H. ３ It is preferable that the modifying gas contains at least one of Br and Br. When the modifying gas contains carbon, a carbon film may be formed on the surface of the non-oxide film W2.

[0079] The modifying gas containing halogen adsorbs halogen onto the surface of the oxide film W1, thereby modifying the surface into a halogen-containing film. The halogen-containing film is an example of the modified film WA. It is considered that the modifying gas containing halogen is more likely to adsorb onto the surface of the oxide film W1 than onto the surface of the non-oxide film W2, and thus more likely to form a halogen-containing film. Furthermore, the modifying gas containing a compound of carbon and halogen removes oxygen from the surface of the oxide film W1. The carbon contained in the modifying gas is used to form CO, CO ２ As a result, it is believed that the halogen element is adsorbed onto the surface of the oxide film W1, forming a halogen-containing film.

[0080] In order to prevent the formation of the etching protection film WB on the surface of the halogen-containing film, it is important that the halogen element is sufficiently adsorbed on the surface of the oxide film W1. If the halogen element is sufficiently adsorbed on the surface of the oxide film W1, there is little exposed surface of the oxide film W1 on which the source gas can be adsorbed. It is thought that the source gas is difficult to adsorb on the surface of the halogen-containing film and is therefore desorbed.

[0081] On the other hand, the surface of the non-oxide film W2 hardly adsorbs halogen compared to the surface of the oxide film W1. Therefore, it is considered that the source gas of the etching protection film WB is adsorbed to the exposed surface of the non-oxide film W2, and the formation of the etching protection film WB progresses. Since a halogen-containing film is formed on the surface of the oxide film W1 due to the adsorption of halogen, the formation of the etching protection film WB is delayed.

[0082] The incubation time of the etching protection film WB is longer on the surface of the oxide film W1 than on the surface of the non-oxide film W2. The difference in incubation time is increased by selectively adsorbing halogen onto the surface of the oxide film W1. Therefore, in step S103, the etching protection film WB can be selectively formed on the surface of the non-oxide film W2, relative to the surface of the oxide film W1 to which halogen has been adsorbed.

[0083] The etching gas for the halogen-containing film is not particularly limited, but is preferably, for example, a rare gas in plasma form. The rare gas in plasma form collides with the halogen-containing film, promoting the formation of volatile metal or semiconductor element halides. The rare gas in plasma form also promotes the desorption of metal or semiconductor element halides by sputtering. As a result, etching of the halogen-containing film progresses. The rare gas includes He, Ne, Ar, Kr, or Xe.

[0084] The etching gas is not limited to a rare gas. ２ , O ２ , COS, N.H. ３ , S.O. ２ , CO ２ , CO, CH ４、 NO ２ , NO or N ２These etching gases may be plasmatized. When the modified film WA is a halogen-containing film, the etching gas may be a ligand exchange gas containing a highly volatile organic metal gas or a metal halide gas. The ligand exchange gas exchanges ligands with the metal or semiconductor element of the oxide film W1 that is bonded to the halogen of the halogen-containing film. As a result, a highly volatile organic compound gas or halide gas containing the metal or semiconductor element of the oxide film W1 is generated. This allows the surface of the oxide film W1 to be etched. The ligand exchange gas may be, for example, Al(CH ３ ) ２ Cl, Al(CH ３ ) ３ , SiCl ４ , TiCl ４ , or Sn(CH ３ COCHCOCH ３ ) ２ Examples include:

[0085] Next, with reference to FIG. 5 , a substrate processing apparatus 100 that performs the above-described substrate processing method will be described. As shown in FIG. 5 , the substrate processing apparatus 100 includes a first processing unit 200A, a second processing unit 200B, a third processing unit 200C, a fourth processing unit 200D, a transfer unit 400, and a control unit 500. The first processing unit 200A performs step S102 of FIG. 1 . The second processing unit 200B performs step S103 of FIG. 1 . The third processing unit 200C performs step S105 of FIG. 1 . The fourth processing unit 200D performs step S107 of FIG. 1 . It is also possible for the first processing unit 200A to perform all of steps S102, S103, S105, and S107 of FIG. 1 .

[0086] The transport unit 400 transports substrates W to the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D. The transport unit 400 loads the substrates W into the processing vessel 210 (see FIG. 6 ) such as the first processing unit 200A, and loads the substrates W out of the processing vessel 210. The transport unit 400 includes a first transport chamber 401 and a first transport mechanism 402. The internal atmosphere of the first transport chamber 401 is the air atmosphere. The first transport mechanism 402 is provided inside the first transport chamber 401. The first transport mechanism 402 includes an arm 403 that holds the substrate W, and travels along rails 404. The rails 404 extend in the arrangement direction of the carriers C.

[0087] The transfer unit 400 also has a second transfer chamber 411 and a second transfer mechanism 412. The internal atmosphere of the second transfer chamber 411 is a vacuum atmosphere. The second transfer mechanism 412 is provided inside the second transfer chamber 411. The second transfer mechanism 412 includes an arm 413 that holds the substrate W, and the arm 413 is arranged to be movable vertically and horizontally and rotatable about a vertical axis. The second transfer chamber 411 is connected to a first processing unit 200A, a second processing unit 200B, a third processing unit 200C, and a fourth processing unit 200D via different gate valves G.

[0088] Furthermore, the transfer unit 400 has a load lock chamber 421 between the first transfer chamber 401 and the second transfer chamber 411. The internal atmosphere of the load lock chamber 421 can be switched between a vacuum atmosphere and an atmospheric atmosphere by a pressure adjustment mechanism (not shown). This allows the interior of the second transfer chamber 411 to be constantly maintained in a vacuum atmosphere. Also, it is possible to prevent gas from flowing from the first transfer chamber 401 into the second transfer chamber 411. Gate valves G are provided between the first transfer chamber 401 and the load lock chamber 421, and between the second transfer chamber 411 and the load lock chamber 421.

[0089] The control unit 500 is, for example, a computer, and includes an arithmetic unit 501 such as a CPU (Central Processing Unit), and a storage unit 502 such as a memory. The storage unit 502 stores programs that control various processes executed in the substrate processing apparatus 100. The control unit 500 controls the operation of the substrate processing apparatus 100 by causing the arithmetic unit 501 to execute the programs stored in the storage unit 502. The control unit 500 controls the first processing unit 200A, the second processing unit 200B, the third processing unit 200C, the fourth processing unit 200D, and the transport unit 400, and performs the above-mentioned substrate processing method.

[0090] The program, i.e., a computer program product, may be supplied in a form recorded on a removable storage medium such as a memory card, an optical disk, or a hard disk drive (HDD). The control unit 500 reads the program from the storage medium and stores it in the storage unit 502. The storage unit 502 includes a storage medium such as an HDD, a solid state drive (SDD), or an electronically erasable programmable read-only memory (EEPROM). The program may be written in advance to the storage medium of the storage unit 502. The control unit 500 may also obtain the program distributed by a remote server device or the like via a network or other communication.

[0091] The control unit 500 includes electronic circuits such as a CPU, a graphics processing unit (GPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC). The control unit 500 executes various control operations described in this specification by executing instruction codes stored in a storage medium such as a memory, or by being a circuit designed for a specific application.

[0092] Next, the operation of the substrate processing apparatus 100 will be described. First, the first transport mechanism 402 removes the substrate W from the carrier C, transports the removed substrate W to the load lock chamber 421, and exits from the load lock chamber 421. Next, the internal atmosphere of the load lock chamber 421 is switched from the atmospheric atmosphere to a vacuum atmosphere. Thereafter, the second transport mechanism 412 removes the substrate W from the load lock chamber 421 and transports the removed substrate W to the first processing unit 200A.

[0093] Next, the first processing unit 200A performs step S102 in Fig. 1. Thereafter, the second transport mechanism 412 removes the substrate W from the first processing unit 200A and transports the removed substrate W to the second processing unit 200B. During this time, the substrate W can be protected by a vacuum atmosphere, and contamination of the substrate W with organic compounds in the air can be suppressed.

[0094] Next, second processing apparatus 200B performs step S103 in Fig. 1 . Next, control unit 500 performs step S104 in Fig. 1 . If the first cycle has not been performed K times (step S104, NO), second transport mechanism 412 removes the substrate W from second processing apparatus 200B and transports the removed substrate W to first processing apparatus 200A. Thereafter, the first cycle is performed again.

[0095] On the other hand, when the first cycle has been performed K times (step S104, YES), the second transport mechanism 412 removes the substrate W from the second processing unit 200B and transports the removed substrate W to the third processing unit 200C. During this time, the substrate W can be protected by a vacuum atmosphere, and contamination of the substrate W with organic compounds in the air can be suppressed.

[0096] Next, the third processing unit 200C performs step S105 in Fig. 1. Next, the control unit 500 performs step S106 in Fig. 1. If the number of times the second cycle has been performed has not reached L (step S106, NO), the second transport mechanism 412 removes the substrate W from the third processing unit 200C and transports the removed substrate W to the first processing unit 200A. Thereafter, the second cycle is performed again.

[0097] On the other hand, when the number of times the second cycle has been performed reaches L (step S106, YES), the second transport mechanism 412 removes the substrate W from the third processing unit 200C and transports the removed substrate W to the fourth processing unit 200D. During this time, the substrate W can be protected by a vacuum atmosphere, and contamination of the substrate W with organic compounds in the air can be suppressed.

[0098] Next, the fourth processing unit 200D performs step S107 in Fig. 1. Next, the control unit 500 performs step S108 in Fig. 1. If the third cycle has not been performed M times (step S108, NO), the second transport mechanism 412 removes the substrate W from the fourth processing unit 200D and transports the removed substrate W to the first processing unit 200A. Thereafter, the third cycle is performed again.

[0099] On the other hand, if the third cycle has been performed M times (step S108, YES), the second transport mechanism 412 removes the substrate W from the fourth processing unit 200D, transports the removed substrate W to the load lock chamber 421, and exits from the load lock chamber 421. The internal atmosphere of the load lock chamber 421 is then switched from a vacuum atmosphere to an atmospheric atmosphere. Thereafter, the first transport mechanism 402 removes the substrate W from the load lock chamber 421 and stores the removed substrate W in the carrier C. Then, the processing of the substrate W is completed.

[0100] Next, the first processing unit 200A will be described with reference to Fig. 6. The configurations of the second processing unit 200B, the third processing unit 200C, and the fourth processing unit 200D are similar to the configuration of the first processing unit 200A, and therefore will not be illustrated or described here.

[0101] The first processing unit 200A includes a substantially cylindrical, airtight processing vessel 210. An exhaust chamber 211 is provided in the center of the bottom wall of the processing vessel 210. The exhaust chamber 211 has, for example, a substantially cylindrical shape that protrudes downward. An exhaust pipe 212 is connected to the exhaust chamber 211, for example, at a side surface of the exhaust chamber 211.

[0102] An exhaust source 272 is connected to the exhaust pipe 212 via a pressure controller 271. The pressure controller 271 includes a pressure adjustment valve such as a butterfly valve. The exhaust pipe 212 is configured so that the pressure inside the processing vessel 210 can be reduced by the exhaust source 272. The pressure controller 271 and the exhaust source 272 constitute a gas exhaust mechanism 270 that exhausts gas inside the processing vessel 210.

[0103] A transfer port 215 is provided on the side surface of the processing vessel 210. The transfer port 215 is opened and closed by a gate valve G. The substrate W is transferred in and out between the processing vessel 210 and the second transfer chamber 411 (see FIG. 5 ) via the transfer port 215.

[0104] A stage 220, which is a holder for holding a substrate W, is provided within the processing vessel 210. The stage 220 holds the substrate W horizontally with the surface to be etched facing upward. The stage 220 is formed in a substantially circular shape in a plan view and is supported by a support member 221. A substantially circular recess 222 for placing a substrate W having a diameter of, for example, 300 mm is formed in the surface of the stage 220. The recess 222 has an inner diameter slightly larger than the diameter of the substrate W. The depth of the recess 222 is configured to be substantially the same as the thickness of the substrate W, for example. The stage 220 is made of a ceramic material such as aluminum nitride (AlN). Alternatively, the stage 220 may be made of a metal material such as nickel (Ni). Note that instead of the recess 222, a guide ring for guiding the substrate W may be provided around the periphery of the surface of the stage 220.

[0105] A grounded lower electrode 223, for example, is embedded in the stage 220. A heating mechanism 224 is embedded below the lower electrode 223. The heating mechanism 224 receives power from a power supply unit (not shown) based on a control signal from the control unit 500 (see FIG. 5), thereby heating the substrate W placed on the stage 220 to a set temperature. If the entire stage 220 is made of metal, the entire stage 220 functions as the lower electrode, so the lower electrode 223 does not need to be embedded in the stage 220. The stage 220 is provided with a plurality of (for example, three) lifting pins 231 for holding and lifting up and down the substrate W placed on the stage 220. The lifting pins 231 are made of a material such as alumina (Al ２ O ３ The lift pins 231 may be made of ceramics such as quartz or the like. The lower ends of the lift pins 231 are attached to a support plate 232. The support plate 232 is connected to a lift mechanism 234 provided outside the processing vessel 210 via a lift shaft 233.

[0106] The lifting mechanism 234 is installed, for example, below the exhaust chamber 211. The bellows 235 is provided between the lifting mechanism 234 and an opening 219 for the lifting shaft 233 formed in the lower surface of the exhaust chamber 211. The support plate 232 may be shaped so that it can be raised and lowered without interfering with the support member 221 of the stage 220. The lifting pins 231 are configured to be able to be raised and lowered by the lifting mechanism 234 between above and below the surface of the stage 220.

[0107] A gas supply unit 240 is provided on the ceiling wall 217 of the processing vessel 210 via an insulating member 218. The gas supply unit 240 serves as an upper electrode and faces the lower electrode 223. A high-frequency power supply 252 is connected to the gas supply unit 240 via a matching unit 251. By supplying high-frequency power of 100 kHz to 2.45 GHz, preferably 450 kHz to 100 MHz, from the high-frequency power supply 252 to the upper electrode (gas supply unit 240), a high-frequency electric field is generated between the upper electrode (gas supply unit 240) and the lower electrode 223, thereby generating capacitively coupled plasma. A plasma generation unit 250 that generates plasma includes the matching unit 251 and the high-frequency power supply 252. Note that the plasma generation unit 250 is not limited to capacitively coupled plasma, and may generate other types of plasma, such as inductively coupled plasma or remote plasma. Note that in steps that do not generate plasma, the gas supply unit 240 does not need to serve as an upper electrode, and the lower electrode 223 is also not required.

[0108] The gas supply unit 240 includes a hollow gas supply chamber 241. A number of holes 242 are arranged, for example, evenly, on the bottom surface of the gas supply chamber 241 to distribute and supply the processing gas into the processing vessel 210. A heating mechanism 243 is embedded in the gas supply unit 240, for example, above the gas supply chamber 241. The heating mechanism 243 is heated to a set temperature by receiving power from a power supply unit (not shown) based on a control signal from the control unit 500.

[0109] A gas supply mechanism 260 is connected to the gas supply chamber 241 via a gas supply path 261. The gas supply mechanism 260 supplies gases to be used in desired steps in FIG. 1 to the gas supply chamber 241 via the gas supply path 261. Although not shown, the gas supply mechanism 260 includes individual pipes for each type of gas, on-off valves provided midway through the individual pipes, and flow rate controllers provided midway through the individual pipes. When the on-off valves open the individual pipes, gas is supplied from the supply source to the gas supply path 261. The supply amount is controlled by the flow rate controller. On the other hand, when the on-off valves close the individual pipes, the supply of gas from the supply source to the gas supply path 261 is stopped.

[0110] Although the embodiments of the substrate processing method and substrate processing apparatus according to the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These changes also naturally fall within the technical scope of the present disclosure.

[0111] This application claims priority based on Japanese Patent Application No. 2024-152914, filed with the Japan Patent Office on September 5, 2024, the entire contents of which are incorporated herein by reference.

[0112] W substrate W1 oxide film W2 non-oxide film WA modified film WB etching protection film

Claims

1. A substrate processing method comprising: preparing a substrate having an oxide film containing oxygen and a non-oxide film substantially free of oxygen in different surface regions; modifying the surface of the oxide film with a modifying gas so as to etch the surface of the oxide film with an etching gas; selectively forming an etching protection film on the surface of the non-oxide film relative to the surface of the oxide film modified with the modifying gas; and etching the surface of the oxide film modified with the modifying gas with the etching gas while protecting the surface of the non-oxide film from the etching gas with the etching protection film.

2. The substrate processing method according to claim 1, wherein the modifying gas contains boron and modifies the surface of the oxide film into a boron oxide film, the etching protection film contains a desired element X, and forming the etching protection film includes supplying to the substrate a source gas containing the element X and a reaction gas that reacts with an adsorbate of the source gas.

3. The reforming gas is BCl ３ , BBr ３ , B.I. ３ , B(CH ３ ) ３ , B ２ H ６ , B.F. ３ , C ９ H ２４ BN ３ , C ３ H ９ B, C ６ H １５ B and B ３ N ３ H ６ The substrate processing method according to claim 2 , further comprising at least one of:

4. The substrate processing method according to claim 2, wherein the source gas contains a compound of the element X and a halogen.

5. The etching gas is He, Ne, Ar, Kr, Xe, H ２ , O ２ , COS, N.H. ３ , S.O. ２ , CO ２ , CO, CH ４ , NO ２ , NO, N ２ , Cl ２ , F ２ , HF, XeF ２ , ClF ３ , BrF ３ , HCl, Br ２ , HBr, I ２ , H.I., N.F. ３ , SOCl ２ , S.O. ２ Cl ２ , SF ６ , C.F. ４ , C.H. ３ F, CHF ３ , C ４ F ６ , C ４ F ８ , C.H. ３ Cl, COCl ２ , and C.H. ３ 3. The method of claim 2, further comprising at least one of: Br; 6. The substrate processing method according to claim 5, wherein the etching gas is converted into plasma.

7. The substrate processing method according to claim 1, wherein the modifying gas contains a halogen without substantially containing carbon, and the halogen is adsorbed onto the surface of the oxide film, and the forming of the etching protective film includes supplying to the substrate a source gas and a reaction gas that reacts with the adsorbed material of the source gas.

8. The reformed gas contains Cl ２ , F ２ , HF, XeF ２ , ClF ３ , BrF ３ , HCl, Br ２ , HBr, I ２ , H.I., N.F. ３ , SOCl ２ , S.O. ２ Cl ２ , and S.F. ６ The substrate processing method according to claim 7 , comprising at least one of:

9. The substrate processing method according to claim 1, wherein the modifying gas contains a compound of carbon and halogen, and causes the halogen to be adsorbed onto the surface of the oxide film, and the forming of the etching protective film includes supplying to the substrate a source gas and a reactive gas that reacts with the adsorbed material of the source gas.

10. The reformed gas is CF ４ , C.H. ３ F, CHF ３ , C ４ F ６ , C ４ F ８ , C.H. ３ Cl, COCl ２ , and C.H. ３ 10. The method of claim 9, further comprising at least one of: Br; 11. The substrate processing method according to claim 1, wherein the oxide film contains a compound of a metal and oxygen or a compound of a semiconductor element and oxygen.

12. The substrate processing method according to claim 1, wherein the non-oxide film has an oxygen content of 0 at % to 10 at %.

13. The etching gas is He, Ne, Ar, Kr, Xe, H ２ , O ２ , COS, N.H. ３ , S.O. ２ , CO ２ , CO, CH ４ , NO ２ , NO, N ２ , Al(CH ３ ) ２ Cl, Al(CH ３ ) ３ , SiCl ４ , TiCl ４ , or Sn(CH ３ COCHCOCH ３ ) ２ The substrate processing method according to claim 7 or 9, comprising at least one of the steps of:

14. The substrate processing method according to claim 13, wherein the etching gas is converted into plasma.

15. The substrate processing method according to claim 1, wherein the first cycle including the supply of the modifying gas and the formation of the etching protection film is repeated a plurality of times.

16. The substrate processing method according to claim 1, wherein a second cycle including supplying the modifying gas, forming the etching protection film, and supplying the etching gas is repeated a plurality of times.

17. The substrate processing method according to claim 1, wherein after the supply of the modifying gas, the formation of the etching protection film, and the supply of the etching gas, the supply of the modifying gas and the supply of the etching gas are carried out one or more times without forming the etching protection film in between.

18. The substrate processing method according to claim 17, wherein a third cycle including supplying the modifying gas, forming the etching protection film, and supplying the etching gas, and subsequently carrying out the supplying of the modifying gas and the supplying of the etching gas one or more times without forming the etching protection film therebetween, is repeated multiple times.

19. A substrate processing apparatus comprising: a processing vessel that accommodates the substrate; a holding unit that holds the substrate inside the processing vessel; and a gas supply unit that supplies gas to the substrate held in the holding unit; a transport unit that loads the substrate into the processing vessel and loads the substrate out of the processing vessel; and a control unit that controls the processing vessel and the transport unit, wherein the control unit controls the processing vessel and the transport unit to perform a substrate processing method according to any one of claims 1 to 12 and 15 to 18.

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