Substrate and substrate processing method

Abstract

This substrate has a photoresist film and an organic film. The photoresist film contains a first metal oxide and reacts to extreme ultra violet (EUV) light. The organic film is formed on the underlay of the photoresist film, has a lower binding energy between a metal and oxygen than that of the first metal oxide constituting the photoresist film, and contains a second metal oxide that becomes dissociated from oxygen by EUV light.

Description

Substrate and substrate processing method

[0001] Various aspects and embodiments of the present disclosure relate to substrates and substrate processing methods.

[0002] The following Patent Document 1 discloses "a method for producing a patterning structure, the method comprising providing a substrate for receiving a pattern, incorporating a radiation absorbing layer on a surface of the substrate, and providing an imaging layer, the radiation absorbing layer being below the imaging layer so as to increase the radiation absorption rate and / or patterning performance of the imaging layer."

[0003] Special Publication No. 2022-550568

[0004] B. L. Henke, E. M. Gullikson, and J. C. Davis, “X-ray interactions: photoabsorption, scattering, transmission, and reflection at E .50 -30000 eV, Z . 1 -92,” Atomic Data and Nuclear Data Tables Volume 54 Issue 2 Pages 181-342, July 1993.

[0005] The present disclosure provides a substrate and a substrate processing method that can achieve oxidation of a photoresist film during exposure.

[0006] A substrate according to one embodiment of the present disclosure includes a photoresist film and an organic film. The photoresist film includes a first metal oxide and is reactive to EUV (Extreme Ultra Violet) light. The organic film is formed below the photoresist film and includes a second metal oxide that has a lower metal-oxygen bond energy than the first metal oxide constituting the photoresist film and dissociates oxygen when exposed to EUV light.

[0007] According to the present disclosure, oxidation of the photoresist film can be achieved during exposure.

[0008] FIG. 1 is a diagram showing EUV absorption cross sections of atoms. FIG. 2 is a diagram illustrating an example of a substrate according to an embodiment. FIG. 3 is a diagram illustrating a case where a substrate according to an embodiment is exposed to EUV. FIG. 4 is a diagram illustrating an example of a case where a metal oxide in an organic film on a substrate according to an embodiment is unevenly distributed. FIG. 5 is a diagram illustrating an example of a verification result according to an embodiment. FIG. 6 is a diagram illustrating an example of a schematic configuration of a film forming apparatus according to an embodiment. FIG. 7 is a diagram illustrating an example of a substrate processing flow according to an embodiment. FIG. 8 is a diagram illustrating an example of a change in a substrate due to substrate processing according to an embodiment.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a substrate and a substrate processing method disclosed in the present application will be described in detail with reference to the drawings. However, the disclosed substrate and substrate processing method are not limited to the embodiments.

[0010] In the manufacture of semiconductor devices, a pattern is formed on a substrate such as a semiconductor wafer by a lithography process. In the lithography process, a photoresist film is formed on the surface of the substrate. Then, in the lithography process, the formed photoresist film is selectively exposed to light through a mask having a predetermined pattern formed thereon, and a development process is performed to form a predetermined pattern in the photoresist film. Conventionally, carbon-based photoresists have been used for forming photoresist films. For example, chemically amplified resists have been used for forming photoresist films.

[0011] In recent years, along with the miniaturization of semiconductor devices, miniaturization has also progressed in lithography technology. One method of miniaturization is shortening the wavelength of the exposure light source. In recent years, EUV (Extreme Ultra Violet) exposure using EUV light has been used.

[0012] Conventional carbon-based photoresist films have poor absorption of EUV light and take a long time to react. Therefore, photoresist films containing metal oxides are used for EUV exposure. For example, metal oxide resists (MOR) such as tin oxide are used for EUV exposure.

[0013] Here, Non-Patent Document 1 shows the EUV absorption cross section of atoms. FIG. 1 is a diagram showing the EUV absorption cross section of atoms. The horizontal axis of FIG. 1 is the atomic number of each atom. The horizontal axis of FIG. 1 is the atomic absorption cross section of the atom. The absorption cross section indicates the proportion of EUV light absorbed when passing through the atom. FIG. 1 shows the absorption cross section of atoms with each atomic number for each atomic number. For example, the absorption cross section of atomic number 12 is the absorption cross section of carbon. The absorption cross section of atomic number 50 is the absorption cross section of tin. Tin has a larger EUV absorption cross section than carbon. In other words, tin has a higher EUV absorption rate than carbon.

[0014] In EUV exposure, a substrate with a photoresist film formed thereon is transported to an EUV exposure tool, where the photoresist film is exposed to EUV light. The substrate is then removed from the EUV exposure tool and subjected to a post-exposure bake (PEB). In the PEB, the EUV-exposed substrate is heated to promote a reaction between oxygen and the exposed portions of the photoresist film.

[0015] Here, due to its development mechanism, it is desirable for the photoresist film to be oxidized immediately after exposure. However, because EUV exposure equipment exposes substrates to EUV light in a high vacuum state, it is difficult to flow gases that promote oxidation, and oxidation of the photoresist film does not progress during exposure. If oxidation of the photoresist film could be achieved during exposure, oxygen would normally be supplied to the photoresist film after exposure using PEB or other methods, but oxidation of the photoresist film could be achieved by in-situ processing within the chamber of the EUV exposure equipment. Furthermore, bonding between the metal oxide and the photoresist film would act as an anchor, improving adhesion.

[0016] Therefore, a technique is provided for realizing oxidation of a photoresist film during exposure.

[0017] (Embodiment) An embodiment will be described. First, an example of a substrate 10 used in substrate processing according to the embodiment will be described. FIG. 2 is a diagram illustrating an example of the substrate 10 according to the embodiment. FIG. 2 shows the substrate 10. The substrate 10 includes a first underlayer film 12, a second underlayer film 13, and an organic film 14 stacked in this order on a silicon substrate 11. The first underlayer film 12 is, for example, SOC (spin-on-carbon) or low-density a-C (amorphous carbon). The second underlayer film 13 is, for example, an organic film, SiC, SiON, or SiOCN. The organic film 14 is, for example, DLC (diamond-like carbon) or a-C (amorphous carbon). The organic film 14 is a film that serves as an underlayer for a photoresist film, which will be described later. Note that the first underlayer film 12, the second underlayer film 13, and the organic film 14 are not limited to the examples described above. Furthermore, the configuration of the substrate 10 shown in FIG. 2 is merely an example and is not limited thereto. Films necessary for manufacturing a semiconductor device are formed on the substrate 10 as needed.

[0018] When manufacturing a semiconductor device, a pattern is formed on the substrate 10 by a lithography process. In the lithography process, a photoresist film containing a metal oxide is formed on the surface of the substrate 10. The metal oxide is an oxide of any of Sn (tin), W (tungsten), Te (tellurium), Sb (antimony), In (indium), Zn (zinc), Zr (zirconium), In (indium), and Hf (hafnium). For example, in EUV exposure, a metal oxide resist film 20 is formed on the surface of the substrate 10 as a photoresist film. For example, a tin oxide film is formed on the substrate 10 as the metal oxide resist film 20.

[0019] In EUV exposure, the substrate 10 on which such a metal oxide resist film 20 has been formed is transported to an EUV exposure device, where exposure is performed by irradiating EUV light onto the metal oxide resist film 20. Since the EUV exposure device performs EUV exposure while maintaining a high vacuum state inside, it is difficult to flow a gas that promotes oxidation, and the reaction of the exposed portion of the metal oxide resist film 20 with oxygen does not proceed.

[0020] Therefore, in the substrate 10 according to the embodiment, a metal oxide that has a lower bond energy between metal and oxygen than the metal oxide contained in the metal oxide resist film 20 and dissociates oxygen when exposed to EUV light is contained in the organic film 14. For example, when the metal oxide resist film 20 is a tin oxide (SnOx) film, the organic film 14 contains a metal oxide that has a lower bond energy between metal and oxygen than tin oxide and dissociates oxygen when exposed to EUV light. Examples of metal oxides that can be contained in the organic film 14 include oxides of Cs (cesium) (CsOx), oxides of Te (tellurium) (TeOx), and oxides of Se (selenium) (SeOx).

[0021] FIG. 3 is a diagram illustrating the case where the substrate 10 according to the embodiment is exposed to EUV. FIG. 3 shows the organic film 14 and metal oxide resist film 20 of the substrate 10 according to the embodiment. The metal oxide resist film 20 contains a bond (Sn-R) between Sn and a ligand (R) such as CHx. When the substrate 10 according to the embodiment is exposed to EUV, the Sn and the ligand (R) are cleaved in the exposed portions of the metal oxide resist film 20. Furthermore, secondary electrons are generated from metal oxides (MeO) such as CsOx, TeOx, and SeOx contained in the organic film 14, and some of these are supplied to the metal oxide resist film 20 to assist in the reaction of the metal oxide resist film 20. When the substrate 10 according to the embodiment is exposed to EUV, oxygen dissociates from the metal oxide in the organic film 14, and the reaction of the oxygen in the exposed portions of the metal oxide resist film 20 progresses. For example, in the exposed portion of the metal oxide resist film 20, oxygen is supplied from the metal oxide (MeO) contained in the organic film 14, causing a reaction as shown in chemical formula (1). In addition to chemical formula (1), a reaction as shown in chemical formula (2) occurs at the interface between the metal oxide resist film 20 and the organic film 14, and the metal oxide and the resist bond to form an anchor, improving adhesion.

[0022]

[0023] In the substrate 10 according to the embodiment, by incorporating a metal oxide into the organic film 14 in this manner, oxidation of the metal oxide resist film 20 can be achieved during exposure.

[0024] The higher the metal oxide content of the organic film 14, the greater the amount of secondary electrons and oxygen generated by EUV exposure. However, as the metal oxide content of the organic film 14 increases, the properties of the metal oxide appear, and the properties of the organic film deteriorate. For this reason, the metal oxide content of the organic film 14 is preferably 1 to 20 Atomic %, and more preferably 5 to 10 Atomic %.

[0025] Furthermore, during EUV exposure, secondary electrons and oxygen generated in a portion of the organic film 14 close to the metal oxide resist film 20 reach the metal oxide resist film 20. For this reason, the metal oxide of the organic film 14 may be unevenly distributed on the metal oxide resist film 20 side. For example, the metal oxide may be unevenly distributed within a range of 20 nm from the interface between the organic film 14 and the metal oxide resist film 20, and more preferably within a range of 5 nm.

[0026] Fig. 4 is a diagram illustrating an example of uneven distribution of metal oxide in the organic film 14 of the substrate 10 according to the embodiment. Fig. 4 schematically shows the metal oxide 14a contained in the organic film 14. Fig. 4 also shows the concentration distribution of the metal oxide 14a with respect to the depth from the interface with the metal oxide resist film 20. Fig. 4 shows a case where the concentration of the metal oxide 14a is gradually increased toward the interface within a range of 5 nm from the interface between the metal oxide resist film 20 and the organic film 14, reaching a maximum of 10 atomic %.

[0027] In this way, by distributing the metal oxide unevenly on the metal oxide resist film 20 side of the organic film 14, it is possible to realize oxidation of the metal oxide resist film 20 during exposure while maintaining the function of the organic film 14.

[0028] The ease of oxygen dissociation in oxides of Cs, Te, and Se varies depending on the oxidized valence. Therefore, Gibbs free energy was calculated for oxides of Sn and Cs, Te, and Se to verify whether an oxidation reaction occurs. Fig. 5 is a diagram showing an example of the verification result according to the embodiment. Fig. 5 shows the results of the calculation of the Gibbs free energy for oxides of Sn and Cs, Te, and Se. ２ O, Cs ２ O ２, Cs ２ O ３ , CsO ２ , CsO ３ , TeO, TeO ２ , TeO ３ , SeO ２ , SeO ３ Regarding Sn, SnO ２ and SnO is reacted with SnO ２ The Gibbs free energy is shown for the reaction of Sn with Cs. When the Gibbs free energy is negative, a reaction occurs in which Sn is oxidized. For example, Cs ２ O ２ , Cs ２ O ３ , CsO ２ , CsO ３ , TeO, TeO ２ , TeO ３ , SeO ２ , SeO ３ Sn is converted to SnO ２ and SnO can be reacted with SnO ２ That is, when the metal oxide resist film 20 is a tin oxide film, the metal oxide contained in the organic film 14 is preferably any one of a divalent or higher oxide of Cs, an oxide of Te, and an oxide of Se.

[0029] It is preferable that the metal oxide contained in the organic film 14 is stable within the organic film 14. Here, the stability of the oxide of Cs will be explained. ２ O, Cs ２ O ２ , Cs ２ O ３ , CsO ２ is stable at room temperature. ３ is CsO at room temperature ２ Therefore, when the metal oxide contained in the organic film 14 is an oxide of Cs, the metal oxide is gradually decomposed into Cs ２ O ２ , Cs ２ O ３ , CsO ２ It is preferable that either of the above is used.

[0030] (Apparatus Configuration) Next, an example of the configuration of the film forming apparatus 100 for forming the organic film 14 according to the embodiment will be described. Fig. 6 is a diagram showing an example of the schematic configuration of the film forming apparatus 100 according to the embodiment.

[0031] The film forming apparatus 100 includes a grounded cylindrical vacuum vessel 101 made of, for example, aluminum. A susceptor 102 is provided at the bottom of the vacuum vessel 101 for placing a substrate 10 thereon. The susceptor 102 is made of, for example, aluminum and is formed in a substantially cylindrical shape. The susceptor 102 also functions as the lower electrode of a parallel plate electrode system. An electrostatic chuck 103 is provided on the upper surface of the susceptor 102. The electrostatic chuck 103 is configured by embedding an electrode 131 in a thin dielectric layer. The electrode 131 is connected to a DC voltage source 133 via a switch 132. When the switch 132 is turned on and a DC voltage is applied from the DC voltage source 133 to the electrode 131, the electrostatic chuck 103 electrostatically attracts the substrate 10. The electrostatic chuck 103 has multiple holes 134 for heat transfer gas. A heat transfer gas (e.g., helium gas) is supplied to the hole 134 from a heat transfer gas supply pipe 135. The electrostatic chuck 103 is configured to supply the heat transfer gas supplied from the heat transfer gas supply pipe 135 to a minute gap between the substrate 10 and the electrostatic chuck 103 through the hole 134. Although not shown, a lifter pin for transferring the substrate 10 is provided, which passes through the electrostatic chuck 103 and the susceptor 102 and moves up and down.

[0032] The susceptor 102 has a flow path 121 formed therein. A coolant supply pipe 122 is connected to one end of the flow path 121 of the susceptor 102, and a coolant discharge pipe 123 is connected to the other end of the flow path 121. The coolant supplied from the coolant supply pipe 122 passes through the flow path 121 of the susceptor 102 and is discharged from the coolant discharge pipe 123. The temperature of the substrate 10 is adjusted, for example, by the cold provided by the coolant and the heat transfer efficiency between the substrate 10 and the electrostatic chuck 103 by the heat transfer gas. A ring body 124 made of an insulating material is provided on the upper peripheral edge of the susceptor 102 to effectively introduce reactive ions into the substrate 10.

[0033] The susceptor 102 is fitted into a flat cylindrical insulator 125 with an open top so as to be insulated from the vacuum vessel 101. A matcher 141 and a first high frequency power supply 104 are connected between the susceptor 102, which is the lower electrode, and a reference potential, for example, earth. The first high frequency power supply 104 is configured to generate high frequency power LF for biasing. The frequency of the high frequency power LF may be the same as or different from the frequency of high frequency power HF for plasma generation, which will be described later. In one embodiment, the high frequency power LF has a frequency lower than that of the high frequency power HF. In one embodiment, the high frequency power HF has a frequency within a range of 100 kHz to 60 MHz.

[0034] An electrode plate 151 is provided on the ceiling of the vacuum chamber 101 so as to be parallel to and face the susceptor 102. The electrode plate 151 constitutes an upper electrode of a parallel plate electrode. The electrode plate 151 is made of a dielectric material (e.g., SiO ２ The electrode plate 151 is made of aluminum coated with a conductive material. The electrode plate 151 has a large number of gas supply holes 152. The electrode plate 151 is supported by an electrode support 153 made of a conductor. A space is formed between the electrode plate 151 and the electrode support 153, and a gas diffusion plate 154 is disposed to divide the space into two spaces, upper and lower. The gas diffusion plate 154 has a plurality of gas holes 156. The electrode support 153 is connected to a gas supply pipe 106. The gas supply pipe 106 is also connected to the electrode support 153 so as to supply a process gas to the space between the electrode support 153 and the gas diffusion plate 154. The process gas supplied from the gas supply pipe 106 is diffused and supplied to the space between the electrode plate 151 and the gas diffusion plate 154 through the plurality of gas holes 156 in the gas diffusion plate 154. The process gas supplied to the space between the electrode plate 151 and the gas diffusion plate 154 is then supplied to the process space through the gas supply holes 152 in the electrode plate 151. The electrode plate 151 and the electrode support 153 are insulated from the vacuum vessel 101 by an insulator 155 .

[0035] A matching box 171 and a second high frequency power supply 107 are connected between the electrode plate 151, which is the upper electrode, and a reference potential, for example, earth. The second high frequency power supply 107 is configured to generate high frequency power HF for plasma generation. In one embodiment, the high frequency power HF has a frequency in the range of 10 MHz to 150 MHz.

[0036] The gas supply pipe 106 is provided with a valve V. The gas supply pipe 106 is connected to a gas supply unit 160. The gas supply unit 160 is provided with at least one gas source capable of supplying various process gases used in film formation. The gas source is connected to the gas supply pipe 106 via a flow rate controller. The flow rate controller may include, for example, a mass flow controller or a pressure-controlled flow rate controller. The gas supply unit 160 supplies various gases from each gas source to the gas supply pipe 106 via the flow rate controller.

[0037] An exhaust pipe 111 is connected to the bottom of the vacuum vessel 101. The exhaust pipe 111 is connected to a vacuum pump 112. The inside of the vacuum vessel 101 is evacuated to a vacuum by the vacuum pump 112 via the exhaust pipe 111.

[0038] Next, a brief description will be given of the process of forming an organic film 14 on a substrate 10 in the film forming apparatus 100. Films up to the second underlayer film 13 are formed on the substrate 10. The substrate 10 is loaded into the vacuum chamber 101, which is maintained at a predetermined vacuum level, from a load lock chamber (not shown) adjacent to the vacuum chamber 101. The substrate 10 is then placed on the susceptor 102 via the lifting and lowering operation of lifter pins (not shown). The susceptor 102 is adjusted to a predetermined temperature in advance. By turning on a switch 132 and applying a DC voltage to the electrode 131, the substrate 10 is attracted and held by the electrostatic chuck 103.

[0039] The film forming apparatus 100 opens the valve V, supplies various gases used in forming the organic film 14 from the gas supply pipe 106, and supplies high frequency power HF and high frequency power LF from the first high frequency power supply 104 and the second high frequency power supply 107, thereby forming the organic film 14.

[0040] An example of processing conditions for forming the organic film 14 is shown below. Processing conditions: Temperature of the susceptor 102: 60° C. Pressure inside the vacuum chamber 101: 3 Pa High frequency power HF: 400 W High frequency power LF: less than 60 W

[0041] First gas condition C ２ H ２ (10%) containing Ar gas: 500 sccm (8.34 × 10 －６ m ３ / s) Ar gas: 80 sccm Processing time: 50 seconds

[0042] Second gas condition C ２ H ２ (10%) Ar gas: 500 sccm Ar gas: 80 sccm Te(CH ３ ) ２ Gas: 0 → 5 sccm (increase by 1 sccm every 1 second) Processing time: 5 seconds

[0043] The film formation apparatus 100 starts forming the organic film 14 under the above processing conditions, supplies various gases under first gas conditions when forming the lower part of the organic film 14, and supplies various gases under second gas conditions when forming the upper part of the organic film 14, thereby forming the organic film 14 with unevenly distributed metal oxide. In this way, for example, as shown in FIG. 4 , the organic film 14 with unevenly distributed metal oxide can be formed on the substrate 10.

[0044] The substrate 10 on which the organic film 14 has been formed is unloaded from the film-forming apparatus 100 in the reverse order of the loading procedure. After the substrate 10 has been unloaded, the film-forming apparatus 100 supplies oxygen gas from the gas supply pipe 106 to clean the inside of the vacuum chamber 101.

[0045] (Substrate Processing) Next, an example of substrate processing including the substrate processing method of the present disclosure will be described. Fig. 7 is a diagram showing an example of the flow of substrate processing according to an embodiment. Fig. 8 is a diagram showing an example of changes in the substrate 10 due to the substrate processing according to an embodiment. As shown in Fig. 8(A), up to the second underlayer film 13 has been formed on the substrate 10.

[0046] An organic film 14 containing a metal oxide is formed on the substrate 10 (step S10). For example, the substrate 10 is transported to a film formation apparatus 100, and the organic film 14 containing a divalent or higher valent Cs oxide, an oxide of Te, and an oxide of Se as metal oxides is formed on the second underlayer film 13 of the substrate 10 by the film formation apparatus 100. For example, the organic film 14 is formed with the metal oxide unevenly distributed on the upper surface side as described above. As a result, the organic film 14 is formed on the second underlayer film 13 of the substrate 10, as shown in FIG. 8B .

[0047] Next, a photoresist film containing a metal oxide is formed on the substrate 10 (step S11). For example, the substrate 10 is transported to a film formation apparatus, and a metal oxide resist film 20 such as a tin oxide film is formed on the substrate 10 in the film formation apparatus. The metal oxide resist film 20 may be formed on the substrate 10 by spin coating or by vacuum film formation. As a result, the metal oxide resist film 20 is formed on the organic film 14 on the substrate 10, as shown in FIG. 8C .

[0048] Next, the substrate 10 is subjected to EUV exposure (step S12). For example, the substrate 10 is transported to an EUV exposure apparatus, and the substrate 10 is subjected to EUV exposure using the EUV exposure apparatus. During EUV exposure, as shown in FIG. 8D, the metal oxide resist film 20 on the substrate 10 is irradiated with EUV light through a mask 30 having a predetermined pattern formed thereon. As shown in FIG. 8E, the metal oxide resist film 20 is formed with exposed portions 21a exposed to EUV light and unexposed portions 21b unexposed to EUV light, corresponding to the mask 30. When the organic film 14 is exposed to EUV light, secondary electrons are generated from the metal oxide in the exposed portions 21a, and oxygen dissociates from the metal oxide in the exposed portions 21a. This causes a reaction of oxygen in the exposed portions of the metal oxide resist film 20. In this way, the substrate 10 can achieve oxidation of the metal oxide resist film 20 during exposure.

[0049] After EUV exposure, the substrate 10 is subjected to PEB (step S13). PEB, which is commonly performed in photolithography processes, is known to have the effect of accelerating chemical reactions caused by exposure. In this embodiment, due to the characteristics of the chemical species used, it is desirable to perform the PEB at a higher temperature setting of 100 to 300°C. For example, by performing the heat treatment in stages at 180°C for 60 seconds and then at 250°C for 60 seconds, the rate of chemical reactions can be controlled more effectively even at higher temperatures, and as a result, the desired pattern dimensions can be formed with greater precision.

[0050] Next, the photoresist film is developed (step S14). For example, the metal oxide resist film 20 has a different etching rate between the exposed portion 21a and the unexposed portion 21b. The metal oxide resist film 20 is developed by etching the metal oxide resist film 20 using the selectivity between the exposed portion 21a and the unexposed portion 21a. For example, the substrate 10 is transported to an etching device, and the metal oxide resist film 20 on the substrate 10 is etched in the etching device. This develops the pattern formed in the metal oxide resist film 20. FIG. 8(F) shows the case where negative tone development is performed, leaving the exposed portion 21a of the metal oxide resist film 20.

[0051] Thereafter, the pattern of the metal oxide resist film 20 thus developed is used to perform a patterning process on the substrate 10. For example, the pattern of the metal oxide resist film 20 is used to etch the first lower layer film 12, the second lower layer film 13, and the organic film 14.

[0052] In the above-described embodiment, the metal oxide resist film 20 is mainly a tin oxide film. However, the disclosed technology is not limited to this. The metal oxide resist film 20 may be an oxide of any of Sn, W, Te, Sb, In, Zn, Zr, In, and Hf. In this case, the metal oxide contained in the organic film 14 may be a metal oxide that has a lower bond energy between metal and oxygen than the metal oxide of the metal oxide resist film 20 and from which oxygen dissociates when exposed to EUV light.

[0053] Furthermore, in the above-described embodiment, the photoresist film is mainly described as a metal oxide resist film 20. However, the disclosed technology is not limited to this. The photoresist film may be any film that contains a metal oxide and reacts to EUV light. For example, the photoresist film may be a chemically amplified resist that contains a metal oxide. The metal oxide contained in the photoresist film is preferably a metal oxide that has a high absorption rate of EUV light, and may be, for example, an oxide of any of Sn, Sn, W, Te, Sb, In, Zn, Zr, In, and Hf.

[0054] The above describes the embodiments. As described above, the substrate 10 according to the above-described embodiments includes a photoresist film and an organic film 14. The photoresist film contains a first metal oxide and is reactive to EUV light. The organic film 14 is formed below the photoresist film and contains a second metal oxide that has a lower metal-oxygen bond energy than the first metal oxide constituting the photoresist film and dissociates oxygen when exposed to EUV light. This allows the substrate 10 according to the embodiments to oxidize the photoresist film during exposure.

[0055] The photoresist film is a metal oxide resist film 20. This allows the substrate 10 according to the embodiment to realize oxidation of the metal oxide resist film 20 during exposure.

[0056] Furthermore, the organic film 14 constitutes an underlayer for the metal oxide resist film 20. This allows the substrate 10 according to the embodiment to realize oxidation of the metal oxide resist film 20 during exposure.

[0057] Furthermore, the second metal oxide is unevenly distributed in the organic film 14 on the metal oxide resist film 20 side. Furthermore, the second metal oxide is unevenly distributed in the organic film 14 within a range of 5 nm from the interface with the metal oxide resist film 20. Furthermore, the concentration of the second metal oxide in the organic film 14 increases the closer it is to the interface with the metal oxide resist film 20. As a result, the substrate 10 according to the embodiment can achieve oxidation of the metal oxide resist film 20 during exposure while maintaining the functionality of the organic film 14.

[0058] The first metal oxide is an oxide of Sn. The second metal oxide is any one of a divalent or higher valent oxide of Cs, an oxide of Te, and an oxide of Se. The divalent or higher valent oxide of Cs is Cs ２ O ２ , Cs ２ O ３ , CsO ２ As a result, the substrate 10 according to the embodiment can oxidize the Sn oxide contained in the photoresist film during exposure.

[0059] (Others) The technology disclosed in the present application is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist thereof.

[0060] It should be noted that the disclosed embodiments are illustrative in all respects and should not be considered limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0061] In addition, the following supplementary notes are disclosed regarding the above-described embodiment.

[0062] (Supplementary Note 1) A substrate comprising: a photoresist film containing a first metal oxide and reacting to EUV (Extreme Ultra Violet) light; and an organic film formed below the photoresist film, the organic film containing a second metal oxide having a lower metal-oxygen bond energy than the first metal oxide constituting the photoresist film, and from which oxygen dissociates when exposed to EUV light.

[0063] (Supplementary Note 2) The substrate according to Supplementary Note 1, wherein the photoresist film is a metal oxide resist film.

[0064] (Supplementary Note 3) The substrate according to Supplementary Note 2, wherein the organic film constitutes an underlayer for the metal oxide resist film.

[0065] (Supplementary Note 4) The substrate according to Supplementary Note 3, wherein the organic film has the second metal oxide unevenly distributed on the metal oxide resist film side.

[0066] (Supplementary Note 5) The substrate according to Supplementary Note 4, wherein the second metal oxide is unevenly distributed in a range of 5 nm from the interface with the metal oxide resist film.

[0067] (Supplementary Note 6) The substrate according to Supplementary Note 4 or 5, wherein the organic film has a higher concentration of the second metal oxide closer to the interface with the metal oxide resist film.

[0068] (Supplementary Note 7) The substrate according to any one of Supplementary Notes 1 to 6, wherein the first metal oxide is an oxide of Sn.

[0069] (Supplementary Note 8) The substrate according to Supplementary Note 7, wherein the second metal oxide is any one of a divalent or higher oxide of Cs, an oxide of Te, and an oxide of Se.

[0070] (Appendix 9) The divalent or higher valent oxide of Cs is Cs ２ O ２ , Cs ２ O ３ , CsO ２ The substrate according to claim 8, wherein the substrate is any one of

[0071] (Supplementary Note 10) A substrate processing method for forming a pattern in a photoresist film that contains a first metal oxide and reacts to EUV (Extreme Ultra Violet) light, the method comprising: a) forming, on a substrate, an organic film that contains a second metal oxide that has a lower metal-oxygen bond energy than the first metal oxide and that dissociates oxygen when exposed to EUV light; b) forming the photoresist film on the organic film on the substrate; c) irradiating the photoresist film with EUV light through a mask having a predetermined pattern formed thereon; d) heat-treating the photoresist film that has been irradiated with EUV light; and e) developing the heat-treated photoresist film to form the pattern.

[0072] REFERENCE SIGNS LIST 10 Substrate 11 Silicon substrate 12 First underlayer film 13 Second underlayer film 14 Organic film 14a Metal oxide 20 Metal oxide resist film 30 Mask 100 Film forming apparatus

Claims

1. A substrate having a photoresist film that contains a first metal oxide and reacts to EUV (Extreme Ultra Violet) light; and an organic film that is formed under the photoresist film and contains a second metal oxide that has a lower metal-oxygen bond energy than the first metal oxide that constitutes the photoresist film and dissociates oxygen when exposed to EUV light.

2. The substrate according to claim 1, wherein the photoresist film is a metal oxide resist film.

3. The substrate according to claim 2, wherein the organic film constitutes an underlayer for the metal oxide resist film.

4. The substrate according to claim 3, wherein the organic film has the second metal oxide unevenly distributed on the metal oxide resist film side.

5. The substrate according to claim 4, wherein the second metal oxide is unevenly distributed within a range of 5 nm from the interface with the metal oxide resist film.

6. The substrate according to claim 4, wherein the organic film has a higher concentration of the second metal oxide closer to the interface with the metal oxide resist film.

7. The substrate according to claim 1, wherein the first metal oxide is an oxide of Sn.

8. The substrate according to claim 7, wherein the second metal oxide is any one of a divalent or higher oxide of Cs, an oxide of Te, and an oxide of Se.

9. The divalent or higher oxide of Cs is Cs ２ O ２ , Cs ２ O ３ , CsO ２ The substrate according to claim 8 , 10. A substrate processing method for forming a pattern in a photoresist film that contains a first metal oxide and reacts to EUV (Extreme Ultra Violet) light, comprising the steps of: a) forming, on a substrate, an organic film that contains a second metal oxide that has a lower metal-oxygen bond energy than the first metal oxide that constitutes the photoresist film, and in which oxygen dissociates when exposed to EUV light; b) forming the photoresist film on the organic film on the substrate; c) irradiating the photoresist film with EUV light through a mask having a predetermined pattern formed thereon; d) heat-treating the photoresist film that has been irradiated with EUV light; and e) developing the heat-treated photoresist film to form the pattern.

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