Substrate processing method and substrate processing system

Abstract

The substrate processing method of the present invention includes: a step of applying a coating liquid containing an organic metal complex, a solvent and an additive to a substrate to form a liquid film of the above-mentioned coating liquid; a step of heating the substrate with the liquid film of the above-mentioned coating liquid formed to form a metal oxide film containing an organic component, wherein the above-mentioned metal oxide film containing an organic component is a metal oxide film containing an organic component contained in the above-mentioned additive; a step of dry etching the above-mentioned metal oxide film containing an organic component as a mask; a step of removing the above-mentioned organic component from the above-mentioned metal oxide film containing an organic component after the above-mentioned dry etching; and a step of removing the film from the above-mentioned metal oxide film containing an organic component by wet etching.

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing system. Background Art

[0002] The method for etching a device layer disclosed in Patent Document 1 includes the steps of depositing the device layer on a substrate; depositing a nanocrystalline diamond layer having an average particle size of less than 6 nm on the device layer; and forming an etching mask from the nanocrystalline diamond layer. Furthermore, the method includes etching the device layer through the etching mask to form a trench and ashing the nanocrystalline diamond layer. In Patent Document 1, the nanocrystalline diamond layer is deposited using a CVD process.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-224823 Summary of the Invention

[0006] Technical problem to be solved by the invention

[0007] The technology according to the present invention provides a substrate processing method and a substrate processing system, which perform etching using a mask having high etching resistance and capable of being formed at low cost, and which can easily remove the mask after etching.

[0008] Technical solutions to technical problems

[0009] One embodiment of the present invention is a substrate processing method for processing a substrate, which includes: a step of applying a coating liquid containing an organic metal complex, a solvent and an additive to a substrate to form a liquid film of the above-mentioned coating liquid; a step of heating the substrate with the liquid film of the above-mentioned coating liquid formed to form a metal oxide film containing an organic component, wherein the above-mentioned metal oxide film containing an organic component is a metal oxide film containing an organic component contained in the above-mentioned additive; a step of dry etching the above-mentioned metal oxide film containing an organic component as a mask; a step of removing the above-mentioned organic component from the above-mentioned metal oxide film containing an organic component after the above-mentioned dry etching; and a step of removing the film from the above-mentioned metal oxide film containing an organic component by wet etching.

[0010] Effects of the Invention

[0011] According to the present invention, a substrate processing method and a substrate processing system can be provided, which can perform etching using a mask that has high etching resistance and can be formed at low cost, and can easily remove the mask after etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1FIG. 1 is a diagram schematically showing a general configuration of a wafer processing system as a substrate processing system according to the present embodiment.

[0013] Figure 2 Is used to illustrate the Figure 1 A flow chart of an example of wafer processing performed by a wafer processing system.

[0014] Figure 3 Schematic partial cross-sectional views showing the state of a wafer W in each step of wafer processing.

[0015] Figure 4 This is a diagram schematically showing the structure of a film formed during wafer processing.

[0016] Figure 5 1 is a diagram showing the depth-direction distribution of the mass density ratios of titanium atoms, oxygen atoms, carbon atoms, and silicon atoms in the wafer W after being heated by the first heating device and the second heating device.

[0017] Figure 6 This is a diagram showing the influence of ultraviolet irradiation on wet etching. DETAILED DESCRIPTION

[0018] In the manufacturing process of semiconductor devices, a semiconductor wafer (hereinafter referred to as a "wafer") is subjected to photolithography to form a resist pattern on the wafer. Then, the resist pattern is used as a mask to etch the processing target layer to form a desired pattern on the processing target layer.

[0019] However, with the miniaturization of semiconductor devices, etching of the target layer requires a high aspect ratio. As a technique for this purpose, a hard mask layer with higher etching resistance than the resist film is formed under the resist film, and the hard mask layer is used as a mask for etching. For example, a silicon oxide film formed from TEOS (Tetra Ethyl Orthosilicate) as a raw material (hereinafter referred to as "TEOS film") is used as the hard mask layer. However, with the emergence of 3D NAND devices, a hard mask layer with even higher etching resistance is required.

[0020] In patent documentation 1, disclose the technology that the nanocrystal diamond layer that will use CVD technology to deposit is utilized as etching mask.But, nanocrystal diamond layer is formed by the CVD method that productivity (through put) is low.Therefore, although nanocrystal diamond layer compares the etching tolerance height with TEOS film, cost height.Hard mask layer is the layer that is removed after the etching using this hard mask layer as mask, and therefore is not preferred for such hard mask layer expending high cost.

[0021] Furthermore, after etching using the hard mask layer as a mask, it is required to be able to easily remove the hard mask layer from the viewpoint of productivity and the like.

[0022] Therefore, the technology involved in the present invention provides a substrate processing method and a substrate processing system that perform etching using a mask that has high etching resistance and can be formed at low cost, and that can easily be removed after etching. Provided are a substrate processing method and a substrate processing system that perform etching using a mask that has high etching resistance and can be formed at low cost, that can easily be removed after etching. Furthermore, in this specification, "etching resistance of a mask" refers to the resistance of the mask when dry etching is performed using the mask.

[0023] Hereinafter, a substrate processing method and a substrate processing system according to the present embodiment will be described with reference to the accompanying drawings. Note that in this specification and the accompanying drawings, elements having substantially the same functional configuration are denoted by the same reference numerals to omit repeated description.

[0024] Figure 1 FIG. 1 is a diagram schematically showing a general configuration of a wafer processing system as a substrate processing system according to the present embodiment.

[0025] As shown in the figure, the wafer processing system K has three processing systems 1 to 3 that perform desired processing on the wafer W as a substrate. In addition, a control device 4 is provided in the wafer processing system K. The control device 4 is, for example, a computer having a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores programs for controlling various processes in the wafer processing system K. In addition, the above-mentioned program can also be recorded in a non-transitory storage medium that can be read by a computer and installed from the storage medium to the control device 4. Part or all of the program can also be implemented by dedicated hardware (circuit board).

[0026] In the first processing system 1 , a photolithography process or the like is performed on a wafer W. The first processing system 1 includes a resist coating apparatus 11 , a developing apparatus 12 , a liquid film forming apparatus 13 , and first to fifth heating apparatuses 21 to 25 .

[0027] The resist coating apparatus 11 supplies resist liquid to the wafer W, and forms a resist liquid film on the wafer W.

[0028] The developing device 12 performs a developing process on the wafer W using a developing solution.

[0029] The liquid film forming device 13 applies a mask layer forming liquid, which is a coating liquid containing an organic metal complex, a solvent and an additive, to the wafer W to form a liquid film of the mask layer forming liquid on the wafer W. The liquid film forming device 13 forms a liquid film of the mask layer forming liquid before forming the resist liquid film using the resist coating device 11. The organic metal complex contained in the mask layer coating liquid is a complex containing a combination of metal atoms and carbon atoms. In this embodiment, an organic titanium complex is used. The solvent can be, for example, propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA) or a solvent obtained by mixing them. In addition to substances for the purpose of improving wettability and inhibiting drying, the additive also includes an organic substance (hereinafter referred to as "density-enhancing organic substance") for the purpose of increasing the film density of the metal oxide film containing an organic component described later. The density-enhancing organic substance can be an organic compound that does not decompose and remains in the film at the heating temperature of the first heating device 21 and the second heating device 22. In particular, in the second heating device 22, as described later, heating is performed at a high temperature to achieve hydrolysis and dehydration condensation of the organic titanium complex. However, the density-enhancing organic substance can use an organic compound that does not decompose even at the high heating temperature of the second heating device 22.

[0030] The resist coating apparatus 11 and the liquid film forming apparatus 13 are spin coating apparatuses that apply a processing liquid to a wafer W by spin coating to form various films. Like conventional spin coating apparatuses, the resist coating apparatus 11 and the liquid film forming apparatus 13 include a mounting table (not shown) for mounting the wafer W, a discharge nozzle (not shown) for discharging various processing liquids, and a rotation mechanism (not shown) for rotating the mounting table and thereby rotating the wafer W to spread the processing liquids on the surface of the wafer W.

[0031] After the liquid film forming device 13 forms a liquid film of the mask layer forming liquid, the first heating device 21 heats the wafer W. The heating by the first heating device 21 removes the solvent and the like from the liquid film of the mask layer forming liquid.

[0032] The second heating device 22 heats the wafer after the wafer has been heated by the first heating device 21. The heating by the second heating device 22 forms an organic component-containing titanium oxide film as a metal oxide film containing an organic component described later.

[0033] The third heating unit 23 heats the wafer W after the resist coating unit 11 forms a liquid resist film and before exposure by the exposure unit (not shown). Specifically, the third heating unit 23 performs a PAB (Pre-applied Bake) process. The exposure unit is, for example, located adjacent to the first processing system 1.

[0034] The fourth heating device 24 heats the wafer W after the exposure and before development by the developing device 12. That is, the fourth heating device 24 performs a PEB (Post Exposure Bake) process.

[0035] The fifth heating device 25 heats the wafer W after the development. That is, the fifth heating device 25 performs a post-bake process.

[0036] The first to fifth heating devices 21 to 25 , like well-known heating devices, include a hot plate (not shown) for placing the wafer W thereon and heating the wafer W at a predetermined temperature.

[0037] Furthermore, the first processing system 1 is provided with a wafer transfer device (not shown) for transferring wafers between devices.

[0038] In the second processing system 2 , plasma processing using plasma is performed on the wafer W. Specifically, dry etching using plasma is performed on the wafer W. The second processing system 2 includes a first dry etching apparatus 31 and a second dry etching apparatus 32 .

[0039] The first dry etching device 31 dry-etches a titanium oxide film containing an organic component, which will be described later, using a resist pattern formed by development by the developing device 12 as a mask, thereby forming a pattern of the titanium oxide film containing an organic component.

[0040] The second dry etching apparatus 32 uses the pattern of the organic titanium oxide film as a mask to dry-etch the target layer, such as an amorphous silicon layer or a metal carbide layer such as a tungsten (W)-containing WBC layer formed directly below the organic titanium oxide film.

[0041] The first dry etching apparatus 31 and the second dry etching apparatus 32 can use a well-known etching apparatus, for example, an RIE (Reactive Ion Etching) apparatus.

[0042] Furthermore, the second processing system 2 is provided with a wafer transfer device (not shown) for transferring wafers between devices.

[0043] In the third processing system 3 , a process such as removing a pattern of a metal oxide film containing an organic component is performed on the wafer W. The third processing system 3 includes a removal device 41 and a wet etching device 42 .

[0044] After dry etching by the second dry etching apparatus 32, the removal apparatus 41 removes the organic components from the titanium oxide film containing an organic component. Specifically, after the dry etching, the removal apparatus 41 removes the density-enhancing organic substances from the pattern of the titanium oxide film containing an organic component. For example, the removal apparatus 41 heats the wafer W while irradiating it with ultraviolet light as energy beams, thereby removing the density-enhancing organic substances and leaving the pattern of the titanium oxide film containing an organic component as the titanium oxide film. In this case, the removal apparatus 41 includes, for example, a stage (not shown) for mounting the wafer W, a UV light source such as a xenon flash lamp or a deuterium lamp (not shown) for irradiating the wafer W on the stage with ultraviolet light having a peak wavelength of 172 nm, and a heating mechanism such as a resistance heater embedded in the stage (not shown). Alternatively, the removal apparatus 41 may further include a processing container (not shown) having the stage disposed therein. The UV light source may be disposed outside the processing container and may irradiate the wafer W with ultraviolet light through an optical window provided in the processing container. The UV light source is configured to irradiate the entire surface of the wafer W with ultraviolet light. The peak wavelength of the ultraviolet rays to be irradiated is not limited to 172 nm, and may be, for example, 150 nm to 200 nm.

[0045] The wet etching device 42 removes the organic component, that is, the film of the density-enhancing organic substance, which is an organic component, from the pattern of the titanium oxide film containing an organic component by wet etching.

[0046] A well-known wet etching device can be used as the wet etching device 42 .

[0047] Furthermore, the third processing system 3 is provided with a wafer transfer device (not shown) for transferring wafers W between devices.

[0048] Next, an example of wafer processing performed in the wafer processing system K configured as described above will be described. Figure 2 This is a flowchart for explaining an example of wafer processing. Figure 3 Schematic partial cross-sectional views showing the state of a wafer W in each step of wafer processing. Figure 4 Schematically shows the structure of the film formed during wafer processing. Figure 3 As shown in (A), an amorphous silicon film (hereinafter referred to as "a-Si film") F1 is formed in advance as a processing target layer.

[0049] (Liquid Film Formation of Mask Layer Forming Liquid)

[0050] First, if Figure 2 and Figure 3As shown in (A), in the liquid film forming device 13 of the first processing system 1, a mask layer forming liquid containing an organic titanium complex, etc. is spin-coated on the surface of the wafer W to form a liquid film F2 of the mask layer forming liquid in a manner covering the a-Si film F1 (step S1). Figure 4 As shown in (A), in the state of the mask layer forming liquid film F2, the organic titanium complex C containing the titanium atoms M and the ligand (R)L is independent of each other, and the titanium atoms M are not bonded to each other. In addition, the mask layer forming liquid film F2 contains the additive A. Although not shown in the figure, the mask layer forming liquid film F2 also contains a solvent.

[0051] (Formation of Titanium Oxide Film Containing Organic Components)

[0052] Next, the wafer W on which the mask layer forming liquid film F2 is formed is heated. Figure 3 As shown in (B), a titanium oxide film F3 containing an organic component is formed as a metal oxide film containing an organic component. Specifically, the liquid film F2 on the a-Si film F1 becomes the titanium oxide film F3 containing an organic component (step S2). The metal oxide film containing an organic component is a metal oxide film containing a density-enhancing organic substance contained in the additive of the mask-forming liquid. Specifically, it is a film in which the density-enhancing organic substance is incorporated into the metal oxide film structure.

[0053] More specifically, in step S2, wafer W, on which a liquid film F2 of the mask layer forming liquid is formed, is first heated to a first temperature T1 in first heating device 21 to remove the solvent from liquid film F2. Unnecessary additives, specifically additives other than the density-enhancing organic compound, are also removed. First temperature T1 is a temperature above the boiling point of the solvent in the mask layer forming liquid that prevents hydrolysis and dehydration condensation, as described later, and is, for example, 150°C to 300°C.

[0054] Next, in the second heating device 22, the wafer W from which the solvent etc. has been removed is heated at a second temperature T2 higher than the first temperature T1, for example, in the air atmosphere. As a result of this heating, moisture and oxygen in the air, such as Figure 4 As shown in (B), the organic titanium complex C is hydrolyzed, and the hydrolyzed organic titanium complex C is dehydrated and condensed, as shown in FIG. Figure 4 As shown in (C), titanium atoms M bond to each other via oxygen (O), forming a titanium oxide film structure MS. During the hydrolysis and dehydration condensation process, the density-enhancing organic substance Y is not removed and remains in the titanium oxide film structure MS, having been incorporated into the film. As described above, the titanium oxide film F3 containing an organic component is a film in which the density-enhancing organic substance Y is incorporated into the titanium oxide film structure MS.

[0055] The thickness of the titanium oxide film F3 containing an organic component after being heated by the second heating device 22 is, for example, 20 to 500 nm. The second temperature T2 is, for example, 350 to 600°C.

[0056] As described above, the density-enhancing organic substance Y contained in the titanium oxide film F3 containing an organic component is an organic compound that does not decompose at the heating temperatures of the first heating device 21 and the second heating device 22. Specifically, the density-enhancing organic substance Y is, for example, a high-molecular-weight organic substance that is not easily decomposed. However, in the case of a chain compound having only single bonds between carbon atoms, if the molecular weight is too high, a metal oxide film structure may not be properly formed. In this case, the density-enhancing organic substance Y can be a cyclic organic compound that is not easily decomposed even with a relatively low molecular weight, or a chain compound having unsaturated bonds between carbon atoms.

[0057] Figure 5 This figure shows the depth-direction distribution of the atomic composition percentages (atomic %) of titanium atoms, oxygen atoms, carbon atoms, and silicon atoms in a wafer W heated by the first heating device 21 and the second heating device 22. The figure shows an example in which a titanium oxide film F3 containing an organic component having a thickness of approximately 400 nm is formed on a bare silicon wafer.

[0058] As shown in the figure, in the titanium oxide film F3 containing an organic component, after being heated by the first heating device 21 and the second heating device 22, the atomic composition percentages of titanium atoms, oxygen atoms, and carbon atoms remain roughly the same throughout the depth direction. In other words, the composition ratio remains roughly the same throughout the depth direction. Furthermore, the proportion of carbon atoms in the titanium oxide film F3 containing an organic component, after being heated by the first heating device 21 and the second heating device 22, is relatively high, at approximately 50%.

[0059] This indicates that the organic components contained in the mask layer forming liquid are not removed and remain in the film heated by the first heating device 21 and the second heating device 22 .

[0060] Furthermore, based on the atomic composition percentage, the structure of the titanium oxide film F3 containing an organic component is considered to be close to that of titanium monoxide. However, it is speculated that the structure of the titanium oxide film F3 containing an organic component is a mixture of portions where the reaction progresses due to heating, resulting in bonds between titanium atoms and oxygen atoms (Ti-O bonds), and portions where unreacted bonds between titanium atoms and ligands (Ti-R bonds), and that the overall structure does not form a pure carbon monoxide structure or a titanium dioxide structure.

[0061] The present inventors have also confirmed that the thickness of the titanium oxide film F3 containing an organic component decreases when the heating temperature in the second heating device 22 reaches a certain temperature (e.g., 600° C.) or higher. The present inventors believe that this is because the density-enhancing organic matter begins to decompose when the heating temperature in the second heating device 22 reaches a certain temperature or higher.

[0062] Return to the description of wafer processing.

[0063] (Formation of Resist Pattern)

[0064] After the titanium oxide film F3 containing an organic component is formed, a resist pattern is formed (step S3).

[0065] Specifically, first, in the resist coating apparatus 11 , a resist liquid is spin-coated on the surface of the wafer W to form a resist liquid film so as to cover the titanium oxide film F3 containing an organic component.

[0066] Next, in the third heating device 23, the wafer W is subjected to PAB treatment, as shown in FIG. Figure 3 As shown in (C), a resist film F4 is formed on the titanium oxide film F3 containing an organic component.

[0067] Next, an exposure device (not shown) is used to expose the wafer in a desired pattern.

[0068] Next, in the fourth heating device 24 , the wafer W is subjected to a PEB process.

[0069] Then, in the developing device 12, the wafer W is subjected to a developing process, such as Figure 3 Then, in the fifth heating device 25, the wafer W is subjected to a post-bake process.

[0070] (Transfer of Resist Pattern)

[0071] After the resist pattern F5 is formed, the resist pattern F5 is transferred to the titanium oxide film F3 containing an organic component, as shown in FIG. Figure 3 As shown in (E), a pattern F6 of a titanium oxide film containing an organic component is formed (step S4).

[0072] Specifically, for example, a wafer W is fed into the second processing system 2. In the first dry etching device 31, the resist pattern F5 is used as a mask to dry-etch the titanium oxide film F3 containing an organic component. The pattern of the resist pattern F5 is transferred to the titanium oxide film F3 containing an organic component. Then, in an ashing device (not shown), the resist pattern F5 is removed. Figure 3As shown in (E), a pattern F6 of the titanium oxide film containing an organic component is formed. In the dry etching of the titanium oxide film containing an organic component F3, for example, chlorine (Cl2) gas or boron trichloride (BCl3) gas is used.

[0073] (Dry Etching of Processing Object Layer)

[0074] Next, in the second dry etching apparatus 32, the a-Si film F1, serving as the target layer, is dry-etched using the pattern F6 of the titanium oxide film containing an organic component as a mask (step S5). A Cl-based gas is used for dry etching the target layer. A Cl-based gas is a gas containing Cl (chlorine), such as hydrogen chloride (HCl). Alternatively, a F-based gas, such as sulfur hexafluoride (SF6) gas containing fluorine (F), may be used instead of the Cl-based gas.

[0075] (Removal of organic components)

[0076] Then, the density-enhancing organic substance Y is removed from the pattern F6 of the titanium oxide film containing an organic component (step S6). Figure 3 As shown in (F), the pattern F6 of the titanium oxide film containing an organic component becomes a pattern F7 of the titanium oxide film not containing the organic substance Y for increasing density.

[0077] Specifically, in step S6, the wafer W is introduced into the third processing system 3. In the removal device 41, the wafer W is heated to a third temperature T3. In this state, the wafer W is irradiated with ultraviolet light to remove the density-enhancing organic substance Y. Ultraviolet irradiation is performed, for example, in an air atmosphere. The ozone and active oxygen generated by the ultraviolet irradiation in the air atmosphere oxidize the density-enhancing organic substance Y. When the oxidized density-enhancing organic substance Y is volatilized and removed, heating can increase the volatilization rate. Furthermore, the higher the third temperature T3, the faster the density-enhancing organic substance Y can be removed. The third temperature T3 is, for example, 200 to 600°C.

[0078] (Wet Etching)

[0079] Then, the pattern F7 of the titanium oxide film that does not contain the density-enhancing organic substance Y is removed by wet etching in the wet etching device 42 (step S7). The etching solution may be, for example, dilute hydrofluoric acid. Alternatively, SPM (sulfuric acid peroxide mixture) may be used instead of dilute hydrofluoric acid.

[0080] When the pattern F7 of the titanium oxide film is thick, for example, the removal process of the organic component in step S6 and the wet etching process in step S7 may be repeated alternately.

[0081] The wafer processing performed in the wafer processing system K is completed as described above.

[0082] Figure 6 This graph shows the effect of ultraviolet irradiation on wet etching. The graph shows the results of wet etching using 0.5% dilute hydrofluoric acid after ultraviolet irradiation on a titanium oxide film formed entirely on a bare silicon wafer, and the results of wet etching without ultraviolet irradiation. 0.5% dilute hydrofluoric acid is used for wet etching of titanium oxide films formed by CVD or other methods. The horizontal axis represents the treatment time, and the vertical axis represents the residual film thickness after wet etching. The ultraviolet irradiation treatment uses ultraviolet rays with a peak wavelength of 172 nm.

[0083] As shown in the figure, without UV irradiation, the wet etching process time is 300 seconds, resulting in only a reduction of approximately 30nm. In contrast, with UV irradiation, even with the same 300-second wet etching process time, the thickness of the titanium oxide film containing an organic component is approximately 250nm, a reduction of approximately 8 times compared to the case without UV irradiation.

[0084] This demonstrates that titanium oxide films containing organic components can be easily peeled off in a short period of time by ultraviolet irradiation. Furthermore, the reason why the wet etching rate of titanium oxide films containing organic components is increased by ultraviolet irradiation is believed to be that the organic substances used for density enhancement hinder the reaction between dilute hydrofluoric acid and the titanium oxide structure. However, ultraviolet irradiation reduces the organic substances used for density enhancement, and this reaction is not hindered.

[0085] In the results shown in the figure, when ultraviolet irradiation treatment is performed, when the wet etching treatment time exceeds 300 seconds, the residual film thickness remains almost unchanged regardless of the wet etching treatment time. Even at a wet etching treatment time of 900 seconds, the titanium oxide film containing an organic component still remains at approximately 80 nm. However, by thinning the titanium oxide film containing an organic component, adjusting the ultraviolet irradiation dose, or changing the ultraviolet wavelength, the titanium oxide film containing an organic component can be removed by wet etching.

[0086] As described above, the substrate processing method of this embodiment includes the steps of applying a mask layer-forming liquid containing an organometallic complex, a solvent, and an additive to a wafer W to form a liquid film of the mask layer-forming liquid; heating the wafer W with the liquid film formed thereon to form a metal oxide film containing an organic component, wherein the metal oxide film containing an organic component is a metal oxide film containing an organic component contained in the additive; and performing dry etching using the metal oxide film containing an organic component as a mask. Specifically, in this embodiment, the metal oxide film containing an organic component serves as a mask when dry etching the target layer. The metal oxide film containing an organic component can be formed simply by applying and heating the mask layer-forming liquid, enabling high productivity and low cost. Furthermore, the metal oxide film containing an organic component has a metal oxide film skeleton in which silicon atoms in a TEOS film are replaced with metal atoms. Since metal atoms are less likely to volatilize than silicon atoms, the metal oxide film has higher etching resistance than a TEOS film. Furthermore, metal oxide films containing organic components have a high density due to their inclusion of organic components, resulting in higher etching resistance. In fact, according to experiments conducted by the present inventors, the selectivity of an organic titanium oxide film, an example of a metal oxide film containing an organic component, when dry etching a-Si film F1 using a Cl-based gas, was 4.9 times that of a TEOS film when the wafer W temperature during dry etching was 400°C. Similarly, the selectivity was 5.9 times at 500°C and 5.7 times at 600°C. Therefore, according to this embodiment, a substrate processing method for dry etching using a mask with high etching resistance can be provided.

[0087] The substrate processing method of this embodiment includes the following steps: removing the organic component from the organic component-containing metal oxide film after dry etching using the organic component-containing metal oxide film as a mask; and removing the film from the organic component-containing metal oxide film by wet etching. These two steps facilitate the removal of the highly etch-resistant organic component-containing metal oxide film used as a mask.

[0088] Therefore, according to this embodiment, it is possible to provide a substrate processing method in which etching is performed using a mask that has high etching resistance and can be formed at low cost, and the mask can be easily removed after etching.

[0089] In this embodiment, as described above, organic matter is intentionally left in the metal oxide film used as a mask. When organic matter remains as described above, it is difficult to remove the metal oxide film when it is no longer needed. Therefore, the organic matter is removed from the metal oxide film after etching.

[0090] Furthermore, in this embodiment, even if the wet etching process time for removing the pattern of the metal oxide film containing an organic component is short, the pattern can be removed. Therefore, damage to the underlying structure of the pattern of the metal oxide film containing an organic component caused by the wet etching can be reduced.

[0091] Furthermore, the metal oxide film containing an organic component can be formed thinner due to its high etching resistance. When formed thinner, the resist pattern can be transferred to the metal oxide film containing an organic component more accurately, and the metal oxide film containing an organic component can be removed more easily.

[0092] In the above description, the density-enhancing organic matter removal process involves heating while irradiating with ultraviolet light. Alternatively, other energy beams, such as electron beams, may be used instead of ultraviolet light. Alternatively, the density-enhancing organic matter removal process may involve simply heating the wafer W at a high temperature without irradiating with energy beams. In this case, heating is preferably performed at a temperature higher than the second temperature T2, the heating temperature of the second heating device 22.

[0093] While the ultraviolet irradiation treatment is performed in an atmospheric atmosphere, an oxidizing gas such as ozone can also be supplied to the treatment space during the ultraviolet irradiation treatment. Furthermore, as described above, an oxidizing gas can also be supplied when heating at high temperatures without ultraviolet irradiation. Supplying an oxidizing gas allows for the removal of organic matter that increases density in a short period of time.

[0094] As described above, various methods can be used to remove the density-enhancing organic substance, resulting in a wide range of organic compounds to choose from as the density-enhancing organic substance. Consequently, there are many options for additives other than organic titanium complexes and density-enhancing organic substances. In other words, according to this embodiment, there are many options for the mask layer forming liquid.

[0095] Furthermore, ultraviolet rays other than those with a peak wavelength of 150 to 200 nm, such as those with a peak wavelength of 222 nm or 254 nm, may be used as ultraviolet rays for removing the organic matter used to increase density. In this case, an oxidizing gas such as ozone gas is supplied to the treatment space during the ultraviolet irradiation treatment.

[0096] In this embodiment, the amorphous silicon layer, etc., serving as the target layer, itself serves as a hard mask, and the actual target layer to be etched is, for example, the ONO film underlying the amorphous silicon layer. Instead of removing the pattern of the metal oxide film containing an organic component, the target layer, such as the ONO film, can be etched using a stacked pattern of the metal oxide film containing an organic component and the amorphous silicon pattern as a mask. Alternatively, the metal oxide film containing an organic component can be directly formed on the target layer, such as the ONO film, and the pattern of the metal oxide film containing an organic component can be used as a mask for dry etching of the ONO film.

[0097] In the above example, heating to the first temperature T1 and heating to the second temperature T2 are performed using different devices, but they may be performed using the same device. In other words, the first heating device 21 and the second heating device 22 may be integrated.

[0098] In the above examples, the metal oxide film constituting the skeleton of the metal oxide film containing an organic component is a titanium oxide film, but it may also be a zirconium oxide, aluminum oxide, tin oxide film, or the like.

[0099] In the above example, dilute hydrofluoric acid and SPM are used in the wet etching of the metal oxide film containing an organic component after the organic matter for increasing density is removed, but other etching solutions can also be used, and the etching solution can also be changed according to the type of the metal oxide film containing an organic component.

[0100] The embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope of the invention (the appended claims) and its gist.

[0101] Description of Reference Numerals

[0102] 13 Liquid film forming device

[0103] 21 First heating device

[0104] 22 Second heating device

[0105] 31. First dry etching device

[0106] 32. Second dry etching device

[0107] 41 Removal device

[0108] 42 wet etching equipment

[0109] F2 liquid film

[0110] F3 Titanium oxide film containing organic components

[0111] A. Additives

[0112] C Organic titanium complex

[0113] K Wafer Handling System

[0114] W chip

[0115] Y Density increase with organic matter.

Claims

1. A substrate processing method for processing a substrate, characterized in that: include: The step of applying a coating liquid comprising an organic metal complex, a solvent and an additive to a substrate to form a liquid film of the coating liquid; a step of heating the substrate on which the liquid film of the coating liquid is formed to form a metal oxide film containing an organic component, wherein the metal oxide film containing an organic component is a metal oxide film containing an organic component contained in the additive; A step of performing dry etching using the metal oxide film containing an organic component as a mask; After the dry etching, removing the organic component in the metal oxide film containing an organic component; and The step of removing the film from the metal oxide film containing an organic component by wet etching.

2. The substrate processing method according to claim 1, wherein: The organic component is used to increase the film density of the metal oxide film containing the organic component.

3. The substrate processing method according to claim 1, wherein: In the step of removing the organic component from the metal oxide film containing an organic component, the substrate on which the metal oxide film containing an organic component is formed is heated while being irradiated with ultraviolet rays to remove the organic component.

4. The substrate processing method according to claim 1, wherein: In the step of forming the metal oxide film containing an organic component, the organic metal complex is hydrolyzed and the hydrolyzed organic metal complexes are subjected to dehydration condensation to form the metal oxide film containing an organic component.

5. The substrate processing method according to claim 4, wherein: The step of forming a metal oxide film containing an organic component comprises: heating the substrate on which the coating liquid film is formed at a first temperature to remove the solvent in the coating liquid film; and The step of heating the substrate from which the solvent has been removed from the liquid film of the coating liquid at a second temperature higher than the first temperature to hydrolyze the organic metal complex and dehydrate and condense the hydrolyzed organic metal complexes to form the metal oxide film containing the organic component.

6. The substrate processing method according to claim 1, wherein: Also includes: forming a resist pattern on the metal oxide film containing an organic component; and a step of transferring the resist pattern to the metal oxide film containing an organic component, The step of performing dry etching performs the dry etching using the metal oxide film containing an organic component to which the resist pattern is transferred as a mask.

7. A substrate processing system for processing a substrate, characterized in that: include: a liquid film forming device for applying a coating liquid comprising an organic metal complex, a solvent, and an additive to a substrate to form a liquid film of the coating liquid; a heating device for heating the substrate on which the liquid film of the coating liquid is formed, thereby forming a metal oxide film containing an organic component, wherein the metal oxide film containing an organic component is a metal oxide film containing an organic component contained in the additive; a dry etching device for performing dry etching using the metal oxide film containing an organic component as a mask; a removal device for removing the organic component from the metal oxide film containing the organic component after the dry etching; and A wet etching device removes the film from which the organic component is removed from the metal oxide film containing the organic component by wet etching.

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