TWI443190B - Cleaning liquid, cleaning method, cleaning system, and method for manufacturing microstructure - Google Patents

Description

Cleaning solution, cleaning method, cleaning system, and method of manufacturing fine structure

The embodiments set forth herein are generally directed to a cleaning fluid, a cleaning method, a cleaning system, and a method for making a microstructure.

Cross-reference to related applications

The application is based on the benefit of the priority of the Japanese Patent Application No. 2009- 219 890, filed on

In fields such as semiconductor devices and MEMS (Micro Electro Mechanical Systems), fine structures having fine walls are fabricated on the surface using lithography. The resist formed during the manufacturing process and then becoming unnecessary is removed using a SPM (sulfuric acid hydrogen peroxide mixture) solution (ie, a mixture of concentrated sulfuric acid and aqueous hydrogen peroxide solution) (for example, see JP- A 2007-123330 (Kokai)).

An oxidizing substance (for example, peroxymonosulfuric acid) produced by mixing concentrated sulfuric acid with an aqueous hydrogen peroxide solution is contained in the SPM solution.

Further, a technique of removing a resist adhered to a wafer and the like by using an oxidizing substance (for example, peroxymonosulfuric acid) produced by electrolyzing an aqueous sulfuric acid solution has been proposed (see JP-A 2006-111943 (Kokai)) .

The technique discussed in JP-A 2007-123330 (Kokai) and JP-A 2006-111943 (Kokai) uses the high oxidative decomposition ability of the produced oxidizing substance to decompose and remove the resist, that is, the organic substance.

Here, when a high-speed operation semiconductor device is manufactured by implanting impurities at a high dose, a modified layer is formed in the surface of the resist by implanting the impurity at the high dose. The resist in which the modified layer is formed cannot be easily removed; and unfortunately, the desired removal margin cannot be obtained only by the oxidative decomposition ability of the oxidizing substance described above.

In general, according to one embodiment, a cleaning fluid comprises an oxidizing species and hydrofluoric acid and exhibits acidity.

In another embodiment, the invention discloses a method of cleaning. The method comprises producing an oxidizing solution comprising an oxidizing species by one selected from the group consisting of an electrolytic sulfuric acid solution, hydrofluoric acid added to a sulfuric acid solution, and a mixed sulfuric acid solution and an aqueous hydrogen peroxide solution. The method comprises supplying an oxidizing solution and hydrofluoric acid to the surface of the article to be cleaned.

In another embodiment, the cleaning system includes a sulfuric acid electrolysis unit, a sulfuric acid supply unit, a cleaning treatment unit, a first hydrofluoric acid supply unit, and an oxidizing solution supply unit. The sulfuric acid electrolysis unit comprises an anode, a cathode, a separator provided between the anode and the cathode, an anode chamber provided between the anode and the separator, and a cathode chamber provided between the cathode and the separator, the sulfuric acid electrolysis unit The sulfuric acid solution is electrolyzed to produce an oxidizing species in the anode compartment. The sulfuric acid supply unit supplies a sulfuric acid solution to the anode chamber and the cathode chamber. The cleaning processing unit performs a cleaning process on the object to be cleaned. The first hydrofluoric acid supply unit supplies hydrofluoric acid to the cleaning processing unit. Further, the oxidizing solution supply unit supplies an oxidizing solution containing the oxidizing substance to the cleaning processing unit.

In another embodiment, the cleaning system includes a sulfuric acid electrolysis unit, a sulfuric acid supply unit, a cleaning treatment unit, a second hydrofluoric acid supply unit, and an oxidation solution supply unit. The sulfuric acid electrolysis unit comprises an anode, a cathode, a separator provided between the anode and the cathode, an anode chamber provided between the anode and the separator, and a cathode chamber provided between the cathode and the separator, the sulfuric acid electrolysis unit The sulfuric acid solution is electrolyzed to produce an oxidizing species in the anode compartment. The sulfuric acid supply unit supplies a sulfuric acid solution to the anode chamber and the cathode chamber. The cleaning processing unit performs a cleaning process on the object to be cleaned. The second hydrofluoric acid supply unit supplies hydrofluoric acid to the anode chamber. Further, the oxidizing solution supply unit supplies an oxidizing solution containing the oxidizing substance to the cleaning processing unit.

In another embodiment, the present invention discloses a method for making a microstructure. The method includes cleaning the object to be cleaned by the above cleaning method and forming a fine structure.

Embodiments will now be described with reference to the drawings. Similar components in the drawings are labeled with the same reference numerals, and the detailed description is omitted as appropriate.

Figure 1 is a schematic diagram illustrating a cleaning system in accordance with this embodiment.

As illustrated in FIG. 1, the cleaning system 5 includes a sulfuric acid electrolysis unit 10, a hydrofluoric acid supply unit 50, a cleaning treatment unit 12, a solution circulation unit 14, and a sulfuric acid supply unit 15.

The sulfuric acid electrolysis unit 10 has a function of electrolyzing a sulfuric acid solution and generating an oxidizing substance in the anode chamber 30. Although when a solution containing an oxidizing substance is used to remove contaminants (for example, deposits such as resists, metal impurities, particles, dry etching residues, cerium oxide, halides, etc.) adhered to the article to be cleaned, The oxidizing ability of the solution containing the oxidizing substance is lowered, but the sulfuric acid electrolysis unit 10 also has a function of restoring the reduced oxidizing ability.

The sulfuric acid electrolysis unit 10 includes an anode 32, a cathode 42, a separator 20 provided between the anode 32 and the cathode 42, an anode chamber 30 provided between the anode 32 and the separator 20, and a cathode chamber provided between the cathode 42 and the separator 20. 40.

The upper end sealing unit 22 is provided at the upper ends of the diaphragm 20, the anode chamber 30, and the cathode chamber 40; and the lower end sealing unit 23 is provided at the lower ends of the diaphragm 20, the anode chamber 30, and the cathode chamber 40. The anode 32 is opposed to the cathode 42 with a diaphragm 20 interposed therebetween. The anode 32 is supported by the anode support 33; and the cathode 42 is supported by the cathode support 43. A DC power source 26 is connected between the anode 32 and the cathode 42.

The anode 32 is made of a conductive anode base member 34 and an anode conductive film 35 formed on the surface of the anode base member 34. The anode base member 34 is supported by the inner surface of the anode support 33; and the anode conductive film 35 faces the anode chamber 30.

The cathode 42 is made of a conductive cathode base member 44 and a cathode conductive film 45 formed on the surface of the cathode base member 44. The cathode base member 44 is supported by the inner surface of the cathode support 43; and the cathode conductive film 45 faces the cathode chamber 40.

An anode inlet 19 is formed on the lower end side of the anode chamber 30; and an anode outlet 17 is formed on the upper end side. The anode inlet 19 and the anode outlet 17 are in communication with the anode chamber 30. A cathode inlet 18 is formed on the lower end side of the cathode chamber 40; and a cathode outlet 16 is formed on the upper end side. Cathode inlet 18 and cathode outlet 16 are in communication with cathode chamber 40.

The hydrofluoric acid supply unit 50 includes a tank 51 holding a hydrogen fluoride (HF) aqueous solution (i.e., hydrofluoric acid), a pump 52, and an on/off valve 71. The tank 51, the pump 52, and the on/off valve 71 are connected to the distribution unit 61 via a pipe line 53 and a pipe line 74. The hydrofluoric acid held in the tank 51 can be supplied to the distribution unit 61 via the piping line 53 and the piping line 74 by the operation of the pump 52. In other words, the hydrofluoric acid supply unit 50 has a function of supplying the hydrofluoric acid held in the tank 51 to the distribution unit 61 of the cleaning processing unit 12; and the hydrofluoric acid supplied to the distribution unit 61 can be supplied to the object to be cleaned The surface of W. It is also possible to supply hydrofluoric acid to the pipe system which is different from the pipe line 74 and the distribution unit 61 by an unillustrated pipe line and distribution unit from a pipe system different from the pipe system containing the oxidizing substance solution (oxidizing solution). Cleaning object W.

The cleaning processing unit 12 has a function of cleaning the object to be cleaned by using a solution containing an oxidizing substance (oxidizing solution) obtained in the sulfuric acid electrolysis unit 10 and hydrofluoric acid supplied from the hydrofluoric acid supply unit 50.

The oxidizing solution obtained in the sulfuric acid electrolysis unit 10 is supplied to the distribution unit 61 provided in the cleaning processing unit 12 via the solution circulation unit 14. The hydrofluoric acid is supplied from the hydrofluoric acid supply unit 50 to the distribution unit 61 provided in the cleaning processing unit 12. The oxidizing solution and the hydrofluoric acid may be supplied in sequence; and the oxidizing solution and the hydrofluoric acid may be supplied substantially simultaneously.

The oxidizing solution and the hydrofluoric acid may be mixed; and the mixture (cleaning liquid) may be supplied. In the case where the hydrofluoric acid supplied from the hydrofluoric acid supply unit 50 is supplied to the piping line 74 substantially simultaneously with the oxidation solution supplied from the sulfuric acid electrolysis unit 10, the piping line 74 forms a mixed unit in which the two solutions are mixed.

Additionally, an unillustrated canister can be provided for mixing the oxidizing solution with the hydrofluoric acid. In this case, the unillustrated can forms a mixing unit. By providing the unillustrated can, the flow rate fluctuation of the mixed liquid (washing liquid) can be buffered, the mixing rate and the like can be adjusted. Further, the nature of the mixing rate of the mixed liquid (washing liquid) can be made more uniform.

The distribution unit 61 has a dispensing nozzle for distributing the oxidizing solution, the hydrofluoric acid, and the mixed solution (cleaning liquid) of the oxidizing solution and the hydrofluoric acid to the object W to be cleaned. A rotary table 62 is provided to place the object W to be cleaned on the rotary table to oppose the dispensing nozzle. A rotary table 62 is provided in the interior of the cover 29. By displacing the oxidizing solution, the hydrofluoric acid, and the mixed solution of the oxidizing solution and the hydrofluoric acid (cleaning liquid) from the dispensing unit 61 toward the object W to be cleaned, the contamination can be removed from the top of the object W to be cleaned. (eg, deposits such as resists, metal impurities, particles, dry etch residues, cerium oxide, halides, etc.).

Although so-called single wafer processing is used in the cleaning processing unit 12 illustrated in FIG. 1, batch processing can also be used.

The oxidizing solution generated in the sulfuric acid electrolysis unit 10 is supplied from the anode outlet 17 to the cleaning processing unit 12 via the solution circulation unit 14. As the solution maintaining unit, the anode outlet 17 is connected to the tank 28 via a piping line 73 in which the opening/closing valve 73a is provided. Tank 28 is connected to distribution unit 61 via a conduit line 74. The oxidizing solution held in the tank 28 is supplied to the dispensing unit 61 via the piping line 74 by the operation of the pump 81. An on/off valve 74a is provided on the distribution side of the pump 81 in the pipe line 74. In this embodiment, the can 28, the pump 81, and the like form an oxidizing solution supply unit that supplies an oxidizing solution containing an oxidizing substance to the cleaning processing unit 12. In this case, the flow rate fluctuation of the oxidizing solution generated in the sulfuric acid electrolysis unit 10 can be buffered by holding and maintaining the oxidizing solution in the tank 28. Temperature control of the oxidizing solution can be performed by providing a heater to the canister 28.

The oxidizing solution discharged from the cleaning processing unit 12 can be recovered by the solution recycling unit 14 and can be re-supplied to the cleaning processing unit 12. For example, the oxidizing solution discharged from the cleaning treatment unit 12 can be supplied to the anode inlet 19 of the sulfuric acid electrolysis unit 10 by sequentially passing through the reflux tank 63, the filter 64, the pump 82, and the on/off valve 76. In other words, the oxidizing solution can be circulated between the sulfuric acid electrolysis unit 10 and the cleaning treatment unit 12. In this case, the oxidizing solution used during the cleaning treatment may be supplied to the sulfuric acid electrolysis unit 10 as needed; subsequently, the oxidizing solution containing the oxidizing substance obtained by performing electrolysis in the sulfuric acid electrolysis unit 10 may be passed through the tank 28 and the like; and the oxidizing solution can be supplied to the cleaning treatment unit 12.

Here, the oxidizing solution can be produced by supplying the diluted sulfuric acid from the sulfuric acid supply unit 15 to the sulfuric acid electrolysis unit 10 and supplying the used oxidation solution to the sulfuric acid electrolysis unit 10 and then performing electrolysis, as needed. The oxidizing solution obtained here can be passed through the tank 28 or the like and supplied to the washing treatment unit 12. By repeating the reuse of the oxidizing solution as much as possible, the amount of the material (chemical solution, etc.) necessary for generating the oxidizing solution and the amount of the effluent during the cleaning process of the article W to be cleaned can be reduced.

Alternatively, the oxidizing solution discharged from the cleaning processing unit 12 can be supplied to the tank 28 by sequentially passing through the reflux tank 63, the filter 64, the pump 82, and the on/off valve 91, that is, without passing through the sulfuric acid electrolysis unit. 10. Here, next, the cleaning process of the article W to be cleaned can be performed by supplying the oxidizing solution from the canister 28 to the cleaning processing unit 12. In this case, the oxidizing solution after use in the cleaning process can be reused. By repeating this reuse of the oxidizing solution as much as possible, the amount of the material (chemical solution, etc.) necessary for generating the oxidizing solution and the amount of the effluent can be reduced.

The hydrofluoric acid discharged from the cleaning processing unit 12 and the mixed solution of the oxidizing solution and the hydrofluoric acid (cleaning liquid) may be similarly recycled and reused. A reflux tank, an on/off valve, and the like, which are not illustrated, may be connected to the cleaning treatment unit 12 for the hydrofluoric acid to separate and recover the hydrofluoric acid and the oxidizing solution. In this case, by sequentially supplying the hydrofluoric acid and the oxidizing solution, separation and recovery can be performed during their respective supply periods. Separate reuse can be achieved by separate reprocessing or the like.

The reflux tank 63 is provided with a discharge line 75 and a discharge valve 75a having a function of discharging the cleaned and removed contaminants in the cleaning processing unit 12 to the outside of the system. The filter 64 has a function of filtering the contaminants contained in the oxidizing solution, the hydrofluoric acid, and the mixed liquid (cleaning liquid) discharged from the cleaning processing unit 12.

The sulfuric acid supply unit 15 has a function of supplying a dilute sulfuric acid solution to the sulfuric acid electrolysis unit 10 (the anode chamber 30 and the cathode chamber 40). The sulfuric acid supply unit 15 includes a pump 80 that supplies the dilute sulfuric acid solution to the anode chamber 30 and the cathode chamber 40, a tank 60 that holds the dilute sulfuric acid, and on/off valves 70 and 72.

A dilute sulfuric acid solution having, for example, not less than 30% by weight and not more than 70% by weight of sulfuric acid concentration is retained in the canister 60. The pump 80 is driven such that the dilute sulfuric acid solution in the tank 60 is supplied to the anode chamber 30 through the on/off valve 70 and via the piping line on the downstream side of the on/off valve 76 and the anode inlet 19. Further, the pump 80 is driven such that the dilute sulfuric acid solution in the tank 60 is supplied to the cathode chamber 40 through the opening/closing valve 72 and via the piping line 86 and the cathode inlet 18 on the downstream side of the opening/closing valve 72.

In this embodiment, damage of the separator 20 due to electrolysis of the sulfuric acid can be suppressed because the sulfuric acid concentration of the solution supplied to the cathode side is low. In other words, the water on the cathode side moves to the anode side during the electrolytic reaction of the sulfuric acid; the sulfuric acid concentration of the solution on the cathode side increases; and the separator 20 is liable to deteriorate. Further, in the case where the ion exchange membrane is used as the separator 20, as the water content is reduced in the concentrated sulfuric acid solution, the resistance of the ion exchange membrane increases; and the tank voltage undesirably increases. Therefore, also to alleviate such problems, the increase in resistance can be suppressed by supplying dilute sulfuric acid to the cathode side to supply water to the ion exchange membrane.

By reducing the concentration of sulfuric acid supplied to the sulfuric acid electrolysis unit 10, the production efficiency of the oxidizing substances (for example, peroxymonosulfuric acid and peroxodisulfuric acid) contained in the oxidizing solution can be increased. The efficiency of increasing the production of the oxidizing species is explained below.

The on/off valves 70, 71, 72, 73a, 74a, 75a, 76 and 91 described above also have the function of controlling the flow rates of various solutions. Pumps 80, 81 and 82 also have the function of controlling the flow rate of various solutions.

The material of the anode support 33, the cathode support 43, the cathode outlet 16, the anode outlet 17, the cathode inlet 18, the anode inlet 19, and the cover 29 of the cleaning treatment unit 12 may advantageously be included in terms of chemical resistance. For example, a fluorocarbon resin such as polytetrafluoroethylene.

The oxidizing solution, the hydrofluoric acid, and the mixture of the oxidizing solution and the hydrofluoric acid (cleaning liquid) supplied to the cleaning treatment unit 12 may include a fluorocarbon resin tube wound with a heat insulator or the like. The pipe can also be provided with an in-line heater made of fluorocarbon resin. The pump for pumping the oxidizing solution, the hydrofluoric acid, and the mixture of the oxidizing solution and the hydrofluoric acid (cleaning liquid) may comprise a telescopic pump made of a fluorocarbon resin having heat resistance and chemical resistance.

The material of the tank holding the sulfuric acid solution may comprise, for example, quartz. The material of each of the cans of the hydrofluoric acid and the mixed solution of the oxidizing solution and the hydrofluoric acid (cleaning liquid) may contain, for example, a fluorocarbon resin. Each of the tanks may also include an overflow control device, a temperature control device, etc., as appropriate.

Here, the treatment time can be shortened by increasing the solution temperature (treatment temperature) (providing a temperature control device to the tank, providing an in-line heater to the pipe, etc.) to increase reactivity with the resist or the like. However, excessively increasing the temperature can cause problems with the allowable temperature and strength of the components of the cleaning system (eg, the piping lines of each unit, the on/off valves, the pumps and tanks, the lid of the cleaning unit, etc.). . The components are typically formed of, for example, a fluorocarbon resin or the like to increase the chemical resistance of the portion in contact with the hydrofluoric acid, the sulfuric acid, and the oxidizing solution. In this case, the required strength is not available in the case where the temperature is too high.

Therefore, it is advantageous to shorten the processing time and the allowable temperature, strength, and the like of the cleaning system, and the temperature of the hydrofluoric acid, the sulfuric acid, and the oxidizing solution is not lower than 100 ° C and not higher than 110 ° C.

The membrane 20 can comprise, for example, a neutral membrane (although having undergone a hydrophilic treatment) comprising a PTFE porous membrane such as the product name Poreflon and the like and positive ion exchange membranes such as those having the product names Nafion, Aciplex, Flemion, and the like. The diaphragm 20 is, for example, about 50 square centimeters in size. The upper end sealing unit 22 and the lower end sealing unit 23 are suitably made of, for example, an O-ring coated with a fluorocarbon resin.

The material of the anode conductive base member 34 may comprise, for example, a p-type crucible and a valve metal such as tantalum. Herein, the "metal for valve" refers to a metal which is uniformly covered with an oxide film by anodization and which has excellent corrosion resistance. Cathode conductive base member 44 can comprise, for example, an n-type crucible.

The material of the anode conductive film 35 and the cathode conductive film 45 may include, for example, glassy carbon. From the standpoint of durability, a conductive diamond film is suitably used in the case where a solution having a relatively high sulfuric acid concentration and a solution to which hydrofluoric acid is added are supplied.

For both the anode and the cathode, the conductive film and the base member may be formed of the same material. For example, in the case where glassy carbon is used as the cathode base member and in which the conductive diamond self-supporting film is used as the anode base member, the base member itself is formed to have electricity which can contribute to the electrolytic reaction. A conductive film of catalytic properties.

Although diamond has stable chemical, mechanical, and thermal properties, it has been difficult to use diamond in electrochemical systems due to poor electrical conductivity. However, the conductive diamond film can be obtained by forming a boron gas and a nitrogen gas while using hot wire chemical vapor deposition (HF-CVD). The conductive diamond film has a "potential window" of, for example, 3 to 5 volts and a resistance of, for example, 5 to 100 milli-ohm-cm.

Here, the potential window is used for the minimum potential required to electrolyze water (not less than 1.2 volts). This potential window varies depending on the material quality. In the case where a material having a wide potential window is used and electrolysis is performed at a potential within the potential window, an electrolysis reaction having an oxidation-reduction potential in the potential window may be performed in preference to electrolysis of water; The oxidation reaction or the reduction reaction of the substance which is difficult to electrolyze is preferentially carried out. Therefore, for substances that cannot undergo conventional electrochemical reactions, decomposition and synthesis can be achieved by using this conductive diamond.

In HF-CVD, decomposition is performed by supplying a source material gas to a tungsten wire in a high temperature state. The free radicals required to form the film are formed. The free radicals diffused into the surface of the substrate then react with other reactive gases to form the film on the desired substrate.

The mechanism of generation of the oxidizing substance in the sulfuric acid electrolysis unit 10 will now be explained.

2A and 2B are schematic views illustrating the mechanism of generation of the oxidized substance. 2A is a schematic side cross-sectional view of the sulfuric acid electrolysis unit. Fig. 2B is a schematic view showing a cross section taken along line A-A of Fig. 2A.

As illustrated in Figures 2A and 2B, an anode 32 and a cathode 42 are provided opposite each other with a membrane 20 interposed therebetween. The anode 32 is supported by the anode support 33, wherein the anode conductive film 35 of the anode 32 faces the anode chamber 30. The cathode 42 is supported by the cathode support 43, wherein the cathode conductive film 45 of the cathode 42 faces the cathode chamber 40. An electrolytic unit outer casing 24 is provided on both end portions of each of the separator 20, the anode support 33, and the cathode support 43.

For example, a 70% by weight sulfuric acid solution (dilute sulfuric acid solution) is supplied from the tank 60 to the anode chamber 30 via the anode inlet 19. The 70 weight percent sulfuric acid solution (the dilute sulfuric acid solution) is also supplied from the canister 60 to the cathode chamber 40 via the cathode inlet 18, for example.

The electrolytic reaction occurs in each of the anode chamber 30 and the cathode chamber 40 by applying a positive voltage to the anode 32 and applying a negative voltage to the cathode 42. The reactions of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3 occur in the anode chamber 30.

Chemical formula 1

2HSO ₄ ^- →S ₂ O ₈ ^2- +2H ⁺ +2e ^-

Chemical formula 2

HSO ₄ ^- +H ₂ O→HSO ₅ ^- +2H ⁺ +2e ^-

Chemical formula 3

2H ₂ O→4H ⁺ +4e ^- +O ₂ ↑

Here, water (H ₂ O) in Chemical Formula 2 and Chemical Formula 3 is used as water contained in 30% of the 70% by weight sulfuric acid solution. In the anode chamber 30, the reaction of Chemical Formula 2 produces peroxomonosulfate ions (HSO ₅ ^- ). The total reaction of Chemical Formula 4 is carried out by the basic reaction of Chemical Formula 1 and Chemical Formula 3 to produce peroxomonosulfate ion (HSO ₅ ^- ) and sulfuric acid. Peroxymonosulfuric acid has a higher cleaning ability than sulfuric acid.

Chemical formula 4

S ₂ O ₈ ^2- +H ⁺ +H ₂ O→HSO ₅ ^- +H ₂ SO ₄

Alternatively, in some cases, the peroxymonosulfate ion (HSO ₅ ^- ) of Chemical Formula 4 is produced after the generation of hydrogen peroxide (H ₂ O ₂ ), such as the basic reaction from Chemical Formula 1 and Chemical Formula 3. The chemical formula 5 is illustrated. In some cases, peroxydisulfuric acid (H ₂ S ₂ O ₈ ) is produced by the reaction of Chemical Formula 1. Chemical Formula 4 and Chemical Formula 5 are secondary reactions of Chemical Formula 1.

Chemical formula 5

S ₂ O ₈ ^2- +H ⁺ +H ₂ O→H ₂ O ₂ +H ₂ SO ₄

Hydrogen gas is generated in the cathode chamber 40 as illustrated by Chemical Formula 6. This occurs because hydrogen ions (H ⁺ ) generated at the anode move to the cathode via the separator 20 and an electrolytic reaction occurs. This hydrogen is discharged from the cathode chamber 40 via the cathode outlet 16.

Chemical formula 6

2H ⁺ +2e ^- →H ₂ ↑

In this embodiment, as illustrated by Chemical Formula 7, by, for example, electrolysis of the sulfuric acid solution, for example, peroxymonosulfuric acid (H ₂ SO ₅ ), peroxydisulfuric acid (H ₂ S ₂ O ₈ ), or the like can be obtained. An oxidizing substance; and an oxidizing solution containing the oxidizing substances can be obtained. Although hydrogen is produced as a by-product, the hydrogen does not affect the removal of the resist or the like.

Chemical formula 7

H ₂ SO ₄ +H ₂ O→oxidized species +H ₂

In the case where peroxymonosulfuric acid is used, the reaction rate of peroxymonosulfuric acid with an organic substance such as a resist is high. Therefore, even a relatively large amount of resist removal in which the amount to be removed can be completed in a short period of time. Further, in the case where peroxymonosulfuric acid is used, the removal can also be achieved at a low temperature. Therefore, it is not necessary to adjust the temperature for ramping up and the like. Further, peroxymonosulfuric acid can be stably produced in a large amount. Therefore, the reaction rate of the peroxymonosulfuric acid and the removed article can be increased even at a low temperature.

Here, in order to increase the production efficiency by shortening the processing time, it is sufficient to increase the amount of the oxidized substance. In this case, the amount of oxidizing species produced can be increased by increasing the size of the device, increasing the applied power, increasing the amount of dilute sulfuric acid solution, and the like. However, such behavior leads to higher production costs and environmental impact. Therefore, it is necessary to efficiently produce the oxidized substance by increasing the electrolysis efficiency.

According to the knowledge obtained by the inventors, in the case of constant electrolysis parameters (e.g., charge, flow rate, temperature, etc.), more oxidizing species can be produced by reducing the concentration of sulfuric acid during electrolysis. Therefore, the production efficiency of the oxidizing substances (for example, peroxymonosulfuric acid and peroxodisulfuric acid) contained in the oxidizing solution can be increased by reducing the sulfuric acid concentration supplied to the sulfuric acid electrolytic unit 10.

Figure 3 is a graph illustrating the effect of the concentration of the oxidizing species and the concentration of the sulfuric acid on the stripping time (removal time). The concentration of the oxidizing species is plotted on the horizontal axis. This stripping time (removal time) is plotted on the vertical axis. In Fig. 3, B1 is a case where the concentration of sulfuric acid is 70% by weight; B2 is a case where the concentration of sulfuric acid is 80% by weight; B3 is a case where the concentration of sulfuric acid is 85 weight%; and B4 is a concentration of 90% by weight of sulfuric acid. And B5 is the case where the concentration of sulfuric acid is 95% by weight.

Figure 3 shows that as the concentration of sulfuric acid decreases, more oxidizing species are produced; and the concentration of such oxidizing species thus increases. Further, for the same sulfuric acid concentration, as the concentration of the oxidizing substances increases (as the amount of the oxidizing substances increases), the stripping time (removal time) is shortened.

In other words, more oxidizing species can be produced as the concentration of sulfuric acid decreases during the stage of production of the oxidizing species. As a result, the stripping time (removal time) can be shortened.

Therefore, in this embodiment, a dilute sulfuric acid solution having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight is supplied to the sulfuric acid electrolysis unit 10.

Therefore, more oxidizing substances can be produced by increasing the electrolysis efficiency of the sulfuric acid electrolysis unit 10. As a result, an oxidizing solution containing a large amount of oxidizing substance can be supplied to the surface of the article W to be cleaned. Therefore, the processing time can be shortened.

Here, when a high-speed operation semiconductor device is manufactured by implanting impurities at a high dose, a modified layer is formed in the surface of the resist by implanting the impurity at the high dose. The resist in which the modified layer is formed is not easily removed; and unfortunately, the desired removal margin cannot be obtained only by the oxidative decomposition ability of the oxidizing substance described above.

In this case, it is perceived that the resist having the modified layer formed in the surface thereof is removed by using a substance having a decomposition ability and a removal ability higher than those of the oxidizing substance. For example, hydrofluoric acid for removing an oxide film and a natural oxide film has high decomposition ability and high removal ability. Therefore, it is conceivable to use hydrofluoric acid to remove a resist formed of a modified layer in its surface.

However, hydrofluoric acid for removing an oxide film and a natural oxide film has the ability to decompose and remove oxides (for example, a cerium oxide film, etc.) and nitrides (for example, a cerium nitride film, etc.). Therefore, the oxide film and the nitride film formed on the wafer can be undesirably removed; and so-called film reduction can occur. In particular, in the case where an oxide film, a nitride film, and the like are exposed at a portion not covered with a resist, such portions may be undesirably removed.

Therefore, it is considered that hydrofluoric acid is not used in applications having the objective of removing organic substances such as resists.

As a result of investigation by the inventors, the following knowledge has been obtained: the migration of hydrofluoric acid to an oxide (for example, a ruthenium dioxide film, etc.) and a nitride (for example, a ruthenium nitride film, etc.) in an acidic solution containing an oxidizing substance can be suppressed. In addition to ability. The following knowledge is also obtained: in this case, even if the ability to remove oxides and nitrides is suppressed, the ability to remove the resist can be increased by including hydrofluoric acid.

Table 1 compares the ability to remove the oxide film, the nitride film, and the resist in which the modified layer is formed.

The cerium oxide film (SiO ₂ ) is formed on the ruthenium substrate by a thermal oxide film method of forming an oxide film. A tantalum nitride film (SiN) is formed on the germanium substrate by LP-CVD forming a nitride film. To form a resist in which a modified layer is formed, a resist is applied to the germanium substrate, exposed, developed, and patterned; and the resist surface is modified by arsenic at a dose of 10 ¹⁶ atoms/cm ² .

The SPM solution is a mixture of a sulfuric acid solution having a sulfuric acid concentration of 98% by weight and a hydrogen peroxide having a hydrogen peroxide concentration of 35 weight percent by a volume ratio of 3:1 (sulfuric acid solution: aqueous hydrogen peroxide solution = 3:1). An aqueous solution is produced. In this case, the mixed sulfuric acid solution and the aqueous hydrogen peroxide solution generate an oxidizing substance (for example, peroxymonosulfuric acid (H ₂ SO ₅ ), peroxodisulfuric acid (H ₂ S ₂ O ₈ ), or the like). Therefore, the SPM solution is also an oxidizing solution containing an oxidizing substance.

The oxidizing solution containing the oxidizing substance is produced by electrolyzing a dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight.

The hydrofluoric acid aqueous solution is prepared by adding hydrofluoric acid to water to form an aqueous solution having a hydrofluoric acid concentration of 1000 ppm.

The sulfuric acid solution to which hydrofluoric acid was added was prepared by adding hydrofluoric acid to a sulfuric acid solution having a sulfuric acid concentration of 98% by weight to provide a hydrofluoric acid concentration of 1000 ppm.

The oxidizing solution to which hydrofluoric acid is added is prepared by adding hydrofluoric acid to a solution produced by electrolyzing a 70 wt% sulfuric acid concentration of a dilute sulfuric acid solution to obtain a hydrofluoric acid concentration of 1000 ppm.

The removal of the oxide film (cerium oxide film, ie, SiO ₂ ) and the nitride film (tantalum nitride film, ie, SiN) is evaluated by the etching rate; and the treatment is performed for 3 minutes at a processing temperature of 60 ° C Time measurement of the amount of etching.

The removal of the resist in which the altered layer was formed was evaluated by visual observation. The treatment temperature at which the resist in which the modified layer was formed was removed was 80 ° C in the case where an aqueous solution of hydrofluoric acid was used and 130 ° C in the case where other solutions were used.

As illustrated in Table 1, in the case where only the SPM solution (the oxidizing solution containing the oxidizing substance produced by mixing the sulfuric acid solution and the aqueous hydrogen peroxide solution) is used, and only the inclusion by the electrolytic dilute sulfuric acid solution is used. The ruthenium dioxide film (SiO ₂ ) and the tantalum nitride film (SiN) were not removed in the case of the oxidizing solution of the oxidizing substance. In other words, in the case where only an oxidizing solution containing an oxidizing substance is used to remove an organic substance such as a resist, the ruthenium dioxide film (SiO ₂ ) and the tantalum nitride film (SiN) are not damaged. However, when the resist in which the modified layer is formed in the surface is removed, the resist is not completely removed and a so-called strip residue (residue) is left.

In the case where the stripping residue (residue) still exists through the processing of the next process, there is a risk that the yield can be significantly lowered. While it is conceivable to solve these problems by using more stringent dry etching conditions and performing other chemical solution processes in previous processes, the cost increases and new problems can occur, such as oxidation of the wafer.

In the case where an aqueous solution of hydrofluoric acid concentrations of 1000 ppm, the etching does not remove the silicon dioxide film desirably (SiO ₂₎ and silicon nitride film (SiN). In other words, in the case where an organic substance such as a resist is removed using only a hydrofluoric acid aqueous solution, there is a risk of damage to the ceria film (SiO ₂ ) and the tantalum nitride film (SiN).

According to the experiment performed by the inventors, it was judged that the resist having the modified layer formed on the surface thereof could not be removed in the case where the hydrofluoric acid aqueous solution was used. In other words, it is concluded that the hydrofluoric acid aqueous solution is not suitable for removing the resist.

In the case where hydrofluoric acid is added to a sulfuric acid solution and a sulfuric acid solution having a hydrofluoric acid concentration of 1000 ppm is used, the hafnium oxide film (SiO ₂ ) and the tantalum nitride film (SiN) are undesirably etched and removed. . In other words, in the case where only a sulfuric acid solution to which hydrofluoric acid is added is used to release an organic substance such as a resist, there is a risk of damage to the cerium oxide film (SiO ₂ ) and the tantalum nitride film (SiN). .

Further, according to the experiment performed by the inventors, it was judged that in the case where the sulfuric acid solution to which hydrofluoric acid was added was used, the resist having the modified layer formed on the surface thereof could not be removed. In other words, it is concluded that the sulfuric acid solution to which hydrofluoric acid is added is not suitable for removing the resist.

In contrast, in the case where an oxidizing solution to which hydrogen fluoride is added (in this experiment, the oxidizing solution has a hydrofluoric acid concentration of 1000 ppm), the tantalum nitride film (SiN) is slightly etched and removed, However, the etching and removal of the ruthenium dioxide film (SiO ₂ ) is suppressed. Further, the resist having the modified layer formed on its surface can be removed without stripping residue (residue).

Therefore, by using an oxidizing solution to which hydrofluoric acid is added as a cleaning liquid, a resist having a modified layer formed on the surface thereof (which is conventionally difficult to remove) can be removed without leaving a peeling residue ( Residue) does not damage the hafnium oxide film (SiO ₂ ) and the tantalum nitride film (SiN).

Conventionally, it is necessary to remove the altered layer of the resist surface by ashing by dry etching and then remove the remaining resist by performing a process using the SPM solution. Therefore, this leads to more processing processes, more processing device types, longer processing times, and the like. On the contrary, by using an oxidizing solution to which hydrofluoric acid is added as a cleaning liquid, a resist having a modified layer formed on the surface thereof can be removed by one type of treatment. Therefore, productivity can be increased, production cost can be reduced, and the like.

Although the case where hydrofluoric acid is added to the oxidizing solution is previously illustrated in this embodiment, the oxidizing solution and the hydrofluoric acid may be supplied to the liquid to be cleaned, for example, sequentially or substantially simultaneously. The surface of the object W is used to perform removal of a resist or the like. This removal can be performed not only on the resist having the modified layer formed on its surface but also on the resist in which the modified layer is not formed. However, it can be used in particular to remove a resist having a modified layer formed in its surface which is conventionally difficult to remove.

A cleaning method according to this embodiment will now be explained.

Figure 4 is a flow chart illustrating the cleaning method.

First, an oxidizing solution containing an oxidizing substance (for example, peroxymonosulfuric acid and peroxodisulfuric acid) is produced by electrolytic sulfuric acid solution (step S1-1). In this case, the oxidizing substances can be efficiently produced by making the sulfuric acid solution having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight.

Then, the temperature of the generated oxidation solution is adjusted (step S1-2). Although this temperature adjustment is not always necessary, it is advantageous to adjust the temperature of the oxidizing solution to not lower than 100 ° C and not higher than 110 ° C because the processing time is shortened, the allowable temperature and strength of the cleaning system, and the like. . This temperature adjustment can be performed on the generated oxidizing solution, the oxidizing solution during the production period (during electrolysis), and any solution in the sulfuric acid solution supplied for the electrolysis.

The temperature of the hydrofluoric acid is adjusted (step S2). Although this temperature adjustment is not always necessary, it is advantageous to adjust the temperature of the hydrofluoric acid to not lower than 100 ° C and not higher than 110 ° C, such as shortening of the treatment time, the allowable temperature and strength of the cleaning system, and the like. .

Then, hydrofluoric acid and the oxidizing solution are supplied to the surface of the article W to be cleaned sequentially or substantially simultaneously (step S3). The supply may be performed from a dispensing unit or the like for each of the articles W to be cleaned and immersed in the hydrofluoric acid and the oxidizing solution in sequence. Further, for example, the supply can be performed sequentially or substantially simultaneously from a separate piping system for the hydrofluoric acid and the oxidizing solution. So-called single wafer processing, batch processing, and the like can be used.

Figure 5 is a flow chart illustrating a cleaning method in accordance with another embodiment.

In this embodiment, the oxidizing solution and the hydrofluoric acid are mixed, and the mixture is supplied to the surface of the article W to be cleaned.

First, an oxidizing solution containing an oxidizing substance (for example, peroxymonosulfuric acid and peroxodisulfuric acid) is produced by electrolyzing a sulfuric acid solution (step S10). In this case, the oxidizing substances can be efficiently produced by making the sulfuric acid solution having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight.

Then, the oxidizing solution and the hydrofluoric acid are mixed to produce a cleaning liquid (step S11). At this time, the concentration of the inorganic acid in the cleaning liquid and the amount of the oxidizing substances are appropriately adjusted.

Next, the temperature of the generated cleaning liquid is adjusted (step S12). Although this temperature adjustment is not always necessary, it is advantageous to adjust the temperature of the cleaning liquid to not lower than 100 ° C and not higher than 110 ° C, such as shortening of the treatment time and the allowable temperature and strength of the cleaning system. This temperature adjustment can be performed on the oxidizing solution and the hydrofluoric acid prior to mixing.

Then, the cleaning liquid (the mixture of the hydrofluoric acid and the oxidizing solution) is supplied to the surface of the article W to be cleaned (step S13). The supply can be performed from the dispensing unit or the like for each of the articles W to be cleaned and to be immersed in the cleaning liquid. So-called single wafer processing, batch processing, and the like can be used.

Although the case where hydrofluoric acid is added to the oxidizing solution after the generation of the oxidizing solution containing the oxidizing substance is illustrated in FIG. 5, the hydrofluoric acid may be added to the sulfuric acid solution, which is the source material of the oxidizing solution. And then this solution can be electrolyzed to produce a cleaning solution containing an oxidizing substance and hydrofluoric acid added thereto (refer to FIG. 6).

Further, a cleaning liquid can be produced by generating an oxidizing solution (SPM solution) containing an oxidizing substance by mixing a sulfuric acid solution with an aqueous hydrogen peroxide solution and adding hydrofluoric acid thereto. Further, a cleaning liquid containing an oxidizing substance and having hydrofluoric acid added thereto can be produced by mixing a sulfuric acid solution, an aqueous hydrogen peroxide solution, and hydrofluoric acid.

In other words, the cleaning liquid is acidic and the solution containing the oxidizing substance and hydrofluoric acid is sufficient. The manufacturing method may include adding an hydrofluoric acid or generating a oxidizing substance from a sulfuric acid solution having hydrofluoric acid added thereto after generating an acidic solution (oxidizing solution) containing an oxidizing substance.

Figure 6 is a schematic diagram illustrating a cleaning system in which a sulfuric acid solution having hydrofluoric acid added thereto is electrolyzed.

As illustrated in FIG. 6, the hydrofluoric acid supply unit 50 includes a tank 51 holding a hydrofluoric acid, a pump 52, and an on/off valve 71. The tank 51, the pump 52, and the on/off valve 71 are connected to the piping line on the side of the sulfuric acid supply unit 15 via the piping line 53a. In other words, the pipe line 53a is connected to the pipe line on the downstream side of the opening/closing valve 70. The hydrofluoric acid held in the tank 51 can be supplied to the anode chamber 30 of the sulfuric acid electrolysis unit 10 via the piping line 53a by the operation of the pump 52. In other words, the hydrofluoric acid supply unit 50 has a function of supplying the hydrofluoric acid held in the tank 51 to the anode chamber 30 of the sulfuric acid electrolysis unit 10; and can be produced by electrolyzing a sulfuric acid solution having hydrofluoric acid added thereto An oxidizing substance and a cleaning liquid having hydrofluoric acid added thereto.

The addition of hydrofluoric acid is advantageous, and at least the anode conductive film 35 is advantageously made of a conductive diamond film.

A method for manufacturing a fine structure according to this embodiment will now be explained.

An example of a method for fabricating a fine structure includes, for example, a method for fabricating a semiconductor device. Here, the manufacturing process of the semiconductor device includes a so-called front-end process, such as a process of forming a pattern on a substrate (wafer) by film formation, resist coating, exposure, development, etching, resist removal, and the like. , inspection process, cleaning process, heat treatment process, impurity introduction process, diffusion process, flattening process, etc. The so-called back-end process includes assembly processes such as cutting, mounting, joining, encapsulation, etc., and functional and reliability inspection processes.

In this case, the removability of the resist can be increased by using the above-described cleaning liquids, such cleaning methods, and the cleaning systems during the resist removal process. In particular, a resist having a modified layer formed on its surface (which is conventionally difficult to remove) may be removed without leaving a residue (residue) and not damaging the cerium oxide film (SiO ₂ ) and Tantalum nitride film (SiN).

Conventionally, it is necessary to remove the altered layer of the resist surface by ashing by dry etching and then remove the remaining resist by performing a process using the SPM solution. Therefore, this leads to more processing processes, more processing device types, longer processing times, and the like. In contrast, by using the cleaning liquids, the cleaning methods, and the cleaning systems described above, the resist having the modified layer formed on the surface thereof can be removed by one type of treatment. Therefore, productivity can be increased, production cost can be reduced, and the like.

The prior art is applicable to processes other than those of the cleaning method and cleaning system of the embodiment described above, and thus detailed description thereof is omitted.

Although the method for manufacturing a semiconductor device is illustrated as an example of the method for manufacturing the fine structure, the method for manufacturing the fine structure is not limited thereto. For example, applications can be realized in fields such as liquid crystal display devices, phase shift masks, micromachines in the field of MEMS, precision optical components, and the like.

In the cleaning system described above, it is not always necessary to provide a configuration for circulating the solution. As illustrated in Figure 7, the solution used in the cleaning process unit 12 can be recycled to the reflux tank 63 along with contaminants and the like and then discharged to the exterior of the system via the discharge conduit line 75.

This treatment can be used not only for removing a resist made of an organic substance, but also for similarly removing metal impurities, particles, dry etching residues, and the like.

For example, during patterning of metal interconnects having a large aspect ratio, a plurality of interconnect metals, oxides and halides of the interconnect metals, barrier metals, oxides and halides of the barrier metals, and the like are deposited. In addition, numerous cerium oxides and halides are deposited during the patterning of a germanium system having a large aspect ratio. In many cases, such materials cannot be removed solely by the oxidizing ability of the oxidizing species of the SPM solution.

However, it is possible to decompose and remove numerous deposits in such deposits by hydrofluoric acid. This removal can be achieved without damaging the ruthenium dioxide film (SiO ₂ ) and the tantalum nitride film (SiN) by using the cleaning liquids described above, the cleaning methods, and the cleaning systems.

In other words, numerous applications can be realized when removing contaminants adhered to the fine structure. In this case, oxides and nitrides are particularly useful when they are on the surface because the contaminants can be removed while inhibiting the removal of the oxides and the nitrides.

A robot can be provided to transport the item to be cleaned. Each of the tank 60 holding the sulfuric acid solution and the tank 51 holding the hydrofluoric acid can be connected to the line of the factory to automatically replenish the solution. A rinsing tank may be provided for rinsing the item to be cleaned after removing the contaminants. The rinsing tank may include an overflow control device and a temperature control device using an in-line heater. It is suitable to use quartz as the material of the rinsing tank.

In the above, the embodiments are illustrated. However, the invention is not limited to the description thereof.

The design modifications that are appropriately made by those skilled in the art in light of the above-described embodiments are also included in the scope of the present invention.

For example, the configuration, dimensions, material qualities, arrangements, etc. of such components of the cleaning systems set forth above are not limited to those illustrated herein and may be modified as appropriate.

Furthermore, the components of the embodiments set forth above may be combined within the scope of the invention; and such combinations are also included within the scope of the invention, including the features of the invention.

Although certain embodiments have been set forth, these embodiments have been shown by way of example only and are not intended to limit the scope of the invention. In fact, the novel liquids, cleaning methods, cleaning systems, and manufacturing methods described herein can be embodied in a variety of other forms; furthermore, the liquids, cleaning methods, and cleanings described herein can be made without departing from the spirit of the invention. Various omissions, substitutions and changes in the form of the system and method of manufacture. The scope of the claims and the equivalents thereof are intended to cover such forms or modifications that are within the scope and spirit of the invention.

5. . . Cleaning system

10. . . Sulfuric acid electrolysis unit

12. . . Cleaning unit

14. . . Solution circulation unit

15. . . Sulfuric acid supply unit

16. . . Cathode outlet

17. . . Anode outlet

18. . . Cathode inlet

19. . . Anode inlet

20. . . Diaphragm

twenty two. . . Upper sealing unit

twenty three. . . Lower sealing unit

twenty four. . . Electrolytic unit housing

26. . . DC power supply

28. . . tank

29. . . cover

30. . . Anode chamber

32. . . anode

33. . . Anode support

34. . . Anode base member

35. . . Anode conductive film

40. . . Cathode chamber

42. . . cathode

43. . . Cathode support

44. . . Cathode base member

45. . . Cathode conductive film

50. . . Hydrofluoric acid unit

51. . . tank

52. . . Pump

53. . . Pipeline

53a. . . Pipeline

60. . . tank

61. . . Distribution unit

62. . . Rotary table

63. . . Reflux tank

64. . . filter

70. . . On/off valve

71. . . On/off valve

72. . . On/off valve

73. . . Pipeline

73a. . . On/off valve

74,85. . . Pipeline

74a. . . On/off valve

75. . . Pipeline

75a. . . On/off valve

76. . . On/off valve

80. . . Pump

81. . . Pump

82. . . Pump

86. . . Pipeline

91. . . On/off valve

Figure 1 is a schematic view illustrating a cleaning system according to this embodiment;

2A and 2B are schematic views illustrating a mechanism of generating an oxidized substance;

Figure 3 is a graph illustrating the effect of the concentration of the oxidizing species and the concentration of sulfuric acid on the removal time;

Figure 4 is a flow chart illustrating the cleaning method;

Figure 5 is a flow chart illustrating a cleaning method in accordance with another embodiment;

Figure 6 is a schematic view showing a cleaning system in which sulfuric acid having hydrofluoric acid added thereto is electrolyzed;

Figure 7 is a schematic diagram illustrating a cleaning system that is not provided with a configuration of a circulating solution.

5. . . Cleaning system

10. . . Sulfuric acid electrolysis unit

12. . . Cleaning unit

14. . . Solution circulation unit

15. . . Sulfuric acid supply unit

16. . . Cathode outlet

17. . . Anode outlet

18. . . Cathode inlet

19. . . Anode inlet

20. . . Diaphragm

twenty two. . . Upper sealing unit

twenty three. . . Lower sealing unit

26. . . DC power supply

28. . . tank

29. . . cover

30. . . Anode chamber

32. . . anode

33. . . Anode support

34. . . Anode base member

35. . . Anode conductive film

40. . . Cathode chamber

42. . . cathode

43. . . Cathode support

44. . . Cathode base member

45. . . Cathode conductive film

50. . . Hydrofluoric acid unit

51. . . tank

52. . . Pump

53. . . Pipeline

60. . . tank

61. . . Distribution unit

62. . . Rotary table

63. . . Reflux tank

64. . . filter

70. . . On/off valve

71. . . On/off valve

72. . . On/off valve

73. . . Pipeline

73a. . . On/off valve

74,85. . . Pipeline

74a. . . On/off valve

75. . . Pipeline

75a. . . On/off valve

76. . . On/off valve

80. . . Pump

81. . . Pump

82. . . Pump

86. . . Pipeline

91. . . On/off valve

Claims (18)

A cleaning solution comprising any one of a method of electrolyzing a sulfuric acid solution having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight, and a method of electrolyzing a sulfuric acid solution by adding a hydrofluoric acid. Oxidizing substances, water, sulfuric acid and hydrofluoric acid. The cleaning solution of claim 1, wherein the oxidizing substance comprises at least one selected from the group consisting of peroxymonosulfuric acid and peroxodisulfuric acid. A cleaning method comprising: producing, by any one of a method selected from the group consisting of a method of electrolyzing sulfuric acid having a concentration of not less than 30% by weight and not more than 70% by weight, and a method of electrolyzing a sulfuric acid solution by adding hydrofluoric acid An oxidizing solution of an oxidizing substance, water, and sulfuric acid, and supplying the oxidizing solution and hydrofluoric acid to the surface of the object to be cleaned. The method of claim 3, wherein the oxidizing substance comprises at least one selected from the group consisting of peroxymonosulfuric acid and peroxodisulfuric acid. The method of claim 3, wherein at least one selected from the group consisting of the temperature of the oxidizing solution and the temperature of the hydrofluoric acid is not lower than 100 ° C and not higher than 110 ° C. The method of claim 3, wherein the oxidizing solution is supplied to the surface of the article to be cleaned sequentially or substantially simultaneously with the hydrofluoric acid. The method of claim 3, wherein the oxidizing solution and the hydrofluoric acid are mixed, and the mixed solution is supplied to the surface of the article to be cleaned. The method of claim 7, wherein the temperature of the mixed solution is not lower than 100 ° C, and not higher than 110 ° C. A cleaning system comprising: a sulfuric acid electrolysis unit comprising an anode, a cathode, a separator provided between the anode and the cathode, an anode chamber provided between the anode and the separator, and a cathode and the separator provided a cathode chamber, the sulfuric acid electrolysis unit electrolyzes a sulfuric acid solution to generate an oxidizing substance in the anode chamber; and a sulfuric acid supply unit that supplies a sulfuric acid solution having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight to the sulfuric acid solution An anode chamber and the cathode chamber; a cleaning processing unit that performs a cleaning process on the object to be cleaned; a first hydrofluoric acid supply unit that supplies hydrofluoric acid to the cleaning processing unit; and a first oxidation solution supply unit, It supplies an oxidizing solution containing the oxidizing substance, water, and sulfuric acid to the cleaning processing unit. The system of claim 9, wherein the first hydrofluoric acid supply unit supplies the hydrofluoric acid to the cleaning processing unit sequentially or substantially simultaneously with the oxidizing solution supplied from the oxidizing solution supply unit. The system of claim 9, further comprising a mixing unit to mix the hydrofluoric acid supplied by the first hydrofluoric acid supply unit with the oxidizing solution supplied from the oxidizing solution supply unit. The system of claim 9, further comprising a solution recycling unit that recovers at least one selected from the oxidizing solution discharged from the cleaning processing unit and the hydrofluoric acid, and supplies the at least one to The cleaning processing unit. The system of claim 12, wherein the solution circulation unit comprises a heater to perform temperature control of the oxidizing solution. The system of claim 9, wherein at least one selected from the group consisting of the anode and the cathode comprises a conductive diamond film formed on a surface of the conductive base member. A cleaning system comprising: a sulfuric acid electrolysis unit comprising an anode, a cathode, a separator provided between the anode and the cathode, an anode chamber provided between the anode and the separator, and a cathode and the separator provided a cathode chamber, the sulfuric acid electrolysis unit electrolyzes a sulfuric acid solution to generate an oxidizing substance in the anode chamber; and a sulfuric acid supply unit that supplies a sulfuric acid solution having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight to the sulfuric acid solution An anode chamber and the cathode chamber; a cleaning processing unit that performs a cleaning process on the object to be cleaned; a second hydrofluoric acid supply unit that supplies hydrofluoric acid to the anode chamber; and a second oxidation solution supply unit that An oxidizing solution containing the oxidizing substance, water, sulfuric acid, and hydrofluoric acid is supplied to the cleaning treatment unit. The system of claim 15, further comprising a solution recycling unit that recovers at least one selected from the oxidizing solution discharged from the cleaning processing unit and the hydrofluoric acid, and supplies the at least one to The cleaning processing unit. The system of claim 15 wherein at least one selected from the group consisting of the anode and the cathode comprises conductive diamond formed on a surface of the conductive base member membrane. A method for manufacturing a fine structure comprising cleaning an object to be cleaned by a cleaning method as claimed in claim 3, and forming a fine structure.