TWI442464B - Cleaning method, cleaning system, and method for manufacturing microstructure - Google Patents

Cleaning method, cleaning system, and method for manufacturing microstructure Download PDF

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Publication number
TWI442464B
TWI442464B TW99130901A TW99130901A TWI442464B TW I442464 B TWI442464 B TW I442464B TW 99130901 A TW99130901 A TW 99130901A TW 99130901 A TW99130901 A TW 99130901A TW I442464 B TWI442464 B TW I442464B
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TW
Taiwan
Prior art keywords
sulfuric acid
solution
oxidizing
weight
unit
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TW99130901A
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Chinese (zh)
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TW201128696A (en
Inventor
Naoya Hayamizu
Makiko Tange
Masaaki Kato
Hiroki Domon
Yusuke Ogawa
Yoshiaki Kurokawa
Nobuo Kobayashi
Original Assignee
Toshiba Kk
Permelec Electrode Ltd
Shibaura Mechatronics Corp
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Priority to JP2009220127A priority Critical patent/JP5148576B2/en
Application filed by Toshiba Kk, Permelec Electrode Ltd, Shibaura Mechatronics Corp filed Critical Toshiba Kk
Publication of TW201128696A publication Critical patent/TW201128696A/en
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Publication of TWI442464B publication Critical patent/TWI442464B/en

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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00Electrolytic production of inorganic compounds or non-metals
    • C25B1/01Products
    • C25B1/28Per-compounds
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/26Processing photosensitive materials; Apparatus therefor
    • G03F7/42Stripping or agents therefor
    • G03F7/422Stripping or agents therefor using liquids only
    • G03F7/423Stripping or agents therefor using liquids only containing mineral acids or salts thereof, containing mineral oxidizing substances, e.g. peroxy compounds

Description

Cleaning method, cleaning system, and method of manufacturing fine structure
The embodiments set forth herein are generally directed to a cleaning method, a cleaning system, and a method for making a microstructure.
This application is based on the benefit of the priority of the Japanese Patent Application No. 2009-220127, filed on Sep.
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 stripped using a SPM (sulfuric acid hydrogen peroxide mixture) solution (ie, a mixture of concentrated sulfuric acid solution and aqueous hydrogen peroxide solution) (for example, see JP) -A 2007-123330 (Kokai)).
Here, it is necessary to repeatedly replenish the aqueous hydrogen peroxide solution by mixing the concentrated sulfuric acid solution with the aqueous hydrogen peroxide solution to generate an oxidizing substance (for example, peroxymonosulfuric acid) which reacts with water and decomposes; The amount. Therefore, it is difficult to maintain the solution mixing rate at a constant value. Further, since the mixing amount of the aqueous hydrogen peroxide solution is increased, the concentration of the sulfuric acid is lowered, and unfortunately, the recycling can no longer be performed.
Therefore, a technique of peeling off a resist adhered to a germanium wafer and the like by electrolyzing an oxidizing substance generated by an aqueous sulfuric acid solution has been proposed (see JP-A 2006-111943 (Kokai)). According to the technique discussed in JP-A 2006-111943 (Kokai), the solution mixing rate can be stabilized by generating the oxidizing substances from the aqueous sulfuric acid solution. However, unfortunately, the processing time is longer than the case where the SPM solution is used to strip the resist. Further, even in the case where the SPM solution is used to strip the resist, the need to increase the productivity more is made necessary to shorten the processing time.
According to one embodiment, the present invention discloses a cleaning method. The method can produce an oxidizing solution containing an oxidizing substance by electrolyzing a dilute sulfuric acid solution. Alternatively, the method can supply a highly concentrated mineral acid solution to the surface of the article to be cleaned individually, sequentially or substantially simultaneously with the oxidizing solution.
According to another embodiment, the cleaning system includes a sulfuric acid electrolysis unit, a dilute sulfuric acid supply unit, a cleaning treatment unit, a mineral 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 anode and the separator. The sulfuric acid electrolysis unit generates an oxidizing substance in the anode chamber by electrolyzing a dilute sulfuric acid solution. The dilute sulfuric acid supply unit supplies a dilute 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 inorganic acid supply unit supplies a highly concentrated inorganic acid solution to the cleaning treatment unit. The oxidizing solution supply unit supplies an oxidizing solution containing the oxidizing substance to the cleaning processing unit. The highly concentrated inorganic acid solution is supplied to the cleaning processing unit individually, sequentially or substantially simultaneously with the oxidizing solution supplied from the oxidizing solution supply unit by the inorganic acid supply unit.
According to still another embodiment, the present invention discloses a method for forming a fine structure. The method can clean the article to be cleaned and form a fine structure by the cleaning method described above.
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 mineral acid supply unit 50, a cleaning treatment unit 12, a solution circulation unit 14, and a dilute 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 the oxidizing ability of the solution containing the oxidizing substance is lowered when the solution containing the oxidizing substance is used to remove the contaminant adhering to the object to be cleaned, 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 inorganic acid supply unit 50 includes a tank 51 that holds a highly concentrated inorganic acid solution, 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. The highly concentrated mineral acid solution held in the tank 51 can be supplied to the distribution unit 61 via the piping line 53 by the operation of the pump 52. In other words, the inorganic acid supply unit 50 has a function of supplying the highly concentrated inorganic acid solution held in the tank 51 to the distribution unit 61 of the cleaning treatment unit 12; and the highly concentrated inorganic acid solution supplied to the distribution unit 61 can be supplied To the surface of the object W to be cleaned. The highly concentrated mineral acid solution is advantageous for solutions having a dehydrating action. Examples of such highly concentrated inorganic acid solutions include, for example, concentrated sulfuric acid solutions having a sulfuric acid concentration of not less than 90% by weight. Temperature control of the highly concentrated mineral acid solution can be performed by providing a heater to the canister 51.
The highly concentrated inorganic acid solution can also be provided by a piping system different from the piping system containing the oxidizing substance solution (oxidizing solution) by providing an unillustrated piping line and distribution unit different from the piping line 74 and the distribution unit 61. Supply to the item W to be cleaned.
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 electrolytic unit 10 and a highly concentrated inorganic acid solution supplied from the inorganic acid supply unit 50.
The oxidizing solution obtained in the sulfuric acid electrolysis unit 10 is supplied to the dispensing unit 61 provided in the cleaning processing unit 12 via the solution circulating unit 14. The highly concentrated inorganic acid solution is supplied from the inorganic acid supply unit 50 to the distribution unit 61 provided in the cleaning processing unit 12. The oxidizing solution and the highly concentrated inorganic acid solution may be sequentially supplied; and the oxidizing solution and the highly concentrated inorganic acid solution may be supplied substantially simultaneously.
The oxidizing solution and the highly concentrated inorganic acid solution may be mixed; and the mixture (cleaning liquid) may be supplied. In the case where the highly concentrated inorganic acid solution supplied from the inorganic 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 mixing unit in which the two solutions are mixed. .
Additionally, an unillustrated canister can be provided for mixing the oxidizing solution with the highly concentrated mineral acid solution. In this case, the unillustrated tank 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. Temperature control of the mixed liquid (washing liquid) can be performed by providing a heater to the unillustrated tank and piping line 74.
The dispensing unit 61 has a dispensing nozzle for dispensing the oxidizing solution, the highly concentrated mineral acid solution, and a mixture (cleaning liquid) of the oxidizing solution and the highly concentrated inorganic acid solution onto the article 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. Dispensing the oxidizing solution, the highly concentrated inorganic acid solution, and the mixed solution of the oxidizing solution and the highly concentrated inorganic acid solution (cleaning liquid) from the dispensing unit 61 toward the object W to be cleaned, in a short period of time Remove contaminants and non-essential substances (eg, resist, etc.) from the top of the object W to be cleaned. The removal of such contaminants and non-essential substances (eg, resists, etc.) from the top of the article W to be cleaned is illustrated below for a short period of time.
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 diluted sulfuric acid from the dilute 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 this reuse of the oxidizing solution as much as possible, the amount of material (chemical solution, etc.) necessary for generating the oxidizing solution and the amount of waste liquid 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 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 used oxidizing solution can be reused during the cleaning process. 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.
Similarly, the highly concentrated mineral acid solution discharged from the cleaning processing unit 12 and a mixture (the cleaning solution) of the oxidizing solution and the highly concentrated inorganic acid solution can be recycled and reused. Specifically, in the case where the inorganic acid sulfuric acid is used, the amount of dilute sulfuric acid supplied from the dilute sulfuric acid supply unit 15 (tank 60) can be reduced because the inorganic acid is the source material liquid of the oxidizing solution. In the case where a problem occurs when the mixture of the inorganic acid solution and the oxidizing solution is reused, an unillustrated reflux tank, an on/off valve or the like may be connected to the cleaning treatment unit 12 for the inorganic acid solution to be separated and The inorganic acid solution and the oxidizing solution are recovered. In this case, by sequentially supplying the inorganic acid solution 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 pipe line 75 and a discharge valve 75a having a function of discharging the cleaned and removed contaminants and unnecessary substances (for example, a resist, etc.) in the cleaning processing unit 12 to the outside of the system. . The filter 64 has a function of filtering the contaminants and non-essential substances (for example, a resist, etc.) contained in the oxidizing solution, the inorganic acid solution, and the mixed solution (cleaning liquid) discharged from the cleaning processing unit 12.
The dilute sulfuric acid supply unit 15 has a function of supplying a dilute sulfuric acid solution to the sulfuric acid electrolysis unit 10 (anode chamber 30 and cathode chamber 40). The dilute 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.
Dilute sulfuric acid having a sulfuric acid concentration of not less than 30% by weight and not more than 70% by weight 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 vessel 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 highly concentrated inorganic acid solution, and the mixture of the oxidizing solution and the highly concentrated inorganic acid solution (cleaning liquid) supplied to the cleaning processing unit 12 may include fluorocarbon wrapped with a heat insulator or the like. Resin tube. The pipe can also be provided with an in-line heater made of fluorocarbon resin. The pump for pumping the oxidizing solution, the highly concentrated inorganic acid solution, and the mixture of the oxidizing solution and the highly concentrated inorganic acid solution (cleaning liquid) may be made of a fluorocarbon resin having heat resistance and chemical resistance. The telescopic pump.
The material of the tank holding the sulfuric acid solution may comprise, for example, quartz. Each of the tanks may include an overflow control device, a temperature control device, etc., as appropriate.
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 is 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.
In this context, the "potential window" is the minimum potential required to electrolyze water (not less than 1.2 volts). This "potential window" differs 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 in the "potential window", electrolysis having an oxidation-reduction potential in the "potential window" can be performed in preference to electrolysis of water. Reaction; and there are cases in which an oxidation reaction or a reduction reaction of a substance which is less likely to undergo electrolysis can be 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 also 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 stripping 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 stripping 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 stripping can also be carried out 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.
However, according to other knowledge obtained by the inventors, as the concentration of the inorganic acid such as sulfuric acid decreases, the processing time for stripping and removing organic substances such as resists is lengthened.
Figure 3 is a graph illustrating the effect of the concentration of the oxidizing species and the concentration of the mineral acid on the stripping time. The oxidized species concentration is plotted on the horizontal axis. This stripping 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. In addition, for the same sulfuric acid concentration, as the concentration of the oxidizing species increases (as the amount of the oxidizing species increases), the stripping time is shortened.
However, when comparing different sulfuric acid concentrations, the stripping time is shortened as the sulfuric acid concentration increases.
In other words, although more oxidizing species may be produced as the concentration of sulfuric acid decreases during the production phase of the oxidizing species, the stripping time may be increased during the stripping phase even when the amounts of the oxidizing species are the same The sulfuric acid concentration is 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. A highly concentrated inorganic acid solution (for example, a concentrated sulfuric acid solution having a sulfuric acid concentration of not less than 90% by weight) is supplied to the surface of the article W to be cleaned without passing through 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. Further, the highly concentrated inorganic acid can be supplied to the surface of the article W to be cleaned without affecting the electrolysis efficiency of the sulfuric acid electrolysis unit 10. As a result, a high concentration of a mineral acid such as sulfuric acid can be used and packaged A solution containing a large amount of oxidizing substance is supplied to the surface of the object W to be cleaned. Therefore, the processing time can be drastically shortened.
Here, according to an experiment performed by the inventors, when a dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight is supplied to the sulfuric acid electrolysis unit 10, an oxidizing solution is generated and supplied to the object to be cleaned by supplying the oxidizing solution When the surface is subjected to stripping of the resist, the stripping time of the resist is about 120 seconds. On the other hand, when the dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight is supplied to the sulfuric acid electrolysis unit 10, the oxidation solution is produced and a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight is added to the oxidation solution to have When an 82% by weight sulfuric acid concentration oxidizing solution is supplied to the surface of the article W to be cleaned, the stripping time is drastically shortened to about 20 seconds.
When a high speed operation semiconductor device is fabricated by implanting impurities at a high dose, a metamorphic layer is formed in the surface of the resist by implanting the impurity at the high dose. The resist having this altered layer is not easily stripped; and unfortunately, the desired stripping margin is not obtained.
According to this embodiment, a highly concentrated inorganic acid and an oxidizing solution containing a large amount of oxidizing substance can be supplied to the surface of the article W to be cleaned. Therefore, even in the case where the altered layer is formed in the resist, the strippability of the resist can be increased.
The reaction heat can be utilized when a highly concentrated mineral acid solution is mixed with an oxidizing solution which is also a low concentration mineral acid solution. As the temperature increases, the reactivity of the oxidizing species contained in the oxidizing solution can be increased. Therefore, the processing time can be shortened.
However, increasing the solution temperature of the sulfuric acid electrolysis unit 10 and the inorganic acid supply unit 50 may result in such components (eg, pipe lines for each unit, on/off valves, pumps and tanks, cleaning unit covers, etc.) Allow temperature and strength problems. 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 highly concentrated inorganic acid solution and the oxidizing solution. In this case, the required strength is impossible to achieve in the case where the temperature is too high.
According to this embodiment, the highly concentrated inorganic acid solution and the oxidizing solution (which is also a low concentration inorganic acid solution) may be mixed before being supplied to the object to be cleaned or supplied to the object W to be cleaned. The heat of reaction is generated. Therefore, the temperature increase of the components can be suppressed; and the reactivity of the oxidizing substance can be increased by increasing the temperature of the mixed solution.
Figure 4 is a graph illustrating the increase in temperature due to heat of reaction. The temperature of the mixture is plotted on a vertical axis. The concentration of the mixture is plotted on the horizontal axis. Prior to the mixing, the temperature of each of the highly concentrated mineral acid solution and the low concentration mineral acid solution (the solution illustrated in Figure 4 is a concentrated sulfuric acid solution and a dilute sulfuric acid solution) is 88 °C. C1 of Fig. 4 illustrates a case where a dilute sulfuric acid solution having a sulfuric acid concentration of 30% by weight is mixed with a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight. C2 of Fig. 4 illustrates a case where a dilute sulfuric acid solution having a sulfuric acid concentration of 50% by weight is mixed with a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight. C3 of Fig. 4 illustrates a case where a dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight is mixed with a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight.
Figure 4 shows that the heat of reaction can be generated by mixing different concentrations of mineral acid (sulfuric acid); and the heat of reaction can be used to increase the temperature of the mixture. The increase in temperature may be greater as the difference between the concentrations of the liquids to be mixed is increased, or as the mixing ratio is set to dilute the mixture (as the mixing ratio is set to decrease the concentration of the mixture).
Therefore, the conditions can be adjusted to perform the optimum stripping by appropriately selecting the concentration of the liquid to be mixed, the mixing ratio, the amount and reactivity of the oxidizing substances, the temperature of the solutions before mixing, and the like.
Although the above describes the case where the highly concentrated inorganic acid solution is mixed with the oxidizing solution which is also a low concentration inorganic acid solution, the case where the highly concentrated inorganic acid solution and the oxidizing solution are sequentially supplied will now be explained. .
Table 1 illustrates a comparison of the time for stripping the resist in the case where the test piece on which the resist was formed on the surface was immersed in the highly concentrated inorganic acid solution and then immersed in the oxidizing solution. The highly concentrated mineral acid solution is a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight. The oxidizing solution is a dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight produced by electrolysis. The temperature of each of the highly concentrated mineral acid solution and the oxidizing solution (as an example) is about 100 to 110 °C.
As illustrated in Table 1, in the case where the impregnation in the highly concentrated inorganic acid solution (concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight) (sample No. 1) was not performed, the stripping was performed. The resist takes 120 seconds. On the contrary, the figure shows the case where the impregnation in the highly concentrated inorganic acid solution (concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight) (sample Nos. 2 to 4) is performed, and the anti-stripping is performed. The etchant takes only about 20 seconds; and the processing time (the stripping time) is drastically shortened. Further, the figure shows that even in the case where the time of immersion in the highly concentrated inorganic acid solution (concentrated sulfuric acid solution having 98% by weight of the sulfuric acid concentration) is short, it is used for stripping the resist. Time has not been greatly affected.
Figure 5 is a graph illustrating the relationship between the stripping time and the number of sequential supplies. The sample number is drawn on the vertical axis. The time for stripping the resist formed on the surface of the test piece (the stripping time) is plotted on the horizontal axis. D1 of Fig. 5 illustrates the immersion in a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight; and D2 illustrates the oxidizing solution produced by electrolyzing a dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight. The condition of impregnation. The temperature of each of the concentrated sulfuric acid solution having 98% by weight of sulfuric acid concentration and the oxidizing solution (as an example) is about 100 to 110 °C.
Sample No. 10 is a case where the impregnation is continued for 1 second in the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight (part D1). The figure shows that it takes about 16 seconds to strip the resist in this case.
Sample No. 11 is a case in which impregnation (Part D1) in which the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight was continued for 1 second and dipping (D2 portion) in the oxidizing solution for 4 seconds was sequentially performed. In this case, the resist was stripped when two times of impregnation in the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight and two times of impregnation in the oxidizing solution were performed. The figure shows the time for stripping the resist for 10 seconds, and the processing time is shortened.
Sample No. 12 is a case in which the impregnation (Part D1) in the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight and the impregnation (Part D2) in the oxidizing solution for 1 second were sequentially performed. In this case, the resist was stripped when four times of impregnation in the 98 weight percent concentrated sulfuric acid solution and four times of impregnation in the oxidizing solution were performed. The figure shows the time for stripping the resist for 8 seconds and more shortens the processing time.
Therefore, the processing time can be shortened by increasing the number of impregnations and subsequently repeating them. As illustrated in Table 1, even in the case where the immersion time in the concentrated sulfuric acid solution was short, the time for stripping the resist was not greatly affected. Therefore, the processing time can be shortened by repeatedly performing the immersion for a short period of time.
Figure 6 is a graph illustrating the effect of the processing temperature (the temperature of the solution). The sample number is drawn on the vertical axis. The time for stripping the resist formed on the surface of the test piece (the stripping time) is plotted on the horizontal axis. E1 of Fig. 6 illustrates the impregnation in a concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight; and E2 illustrates the impregnation in an oxidizing solution produced by electrolyzing a dilute sulfuric acid solution having a sulfuric acid concentration of 70% by weight. The situation.
Sample No. 20 is a case in which the concentration of the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight is room temperature and the temperature of the oxidizing solution is 75 ° C; and by immersing in the concentration of sulfuric acid having 98% by weight The resist was stripped in the sulfuric acid solution for 5 seconds and then immersed in the oxidizing solution to strip the resist. In this case, the time for stripping the resist was 520 seconds.
Sample No. 21 is a case in which the concentration of the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight is 75 ° C; the temperature of the oxidizing solution is 75 ° C; and by immersing in the concentration of sulfuric acid having 98% by weight The resist was stripped in the sulfuric acid solution for 5 seconds and then immersed in the oxidizing solution to strip the resist. In this case, the time for stripping the resist was 360 seconds.
Sample No. 22 is a case in which the concentration of the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight is 100 ° C; the temperature of the oxidizing solution is 75 ° C; and by immersing in the concentration of sulfuric acid having 98% by weight The resist was stripped in the sulfuric acid solution for 5 seconds and then immersed in the oxidizing solution to strip the resist. In this case, the time for stripping the resist was 80 seconds.
Sample No. 23 is a case in which the concentration of the concentrated sulfuric acid solution having a sulfuric acid concentration of 98% by weight is 100 ° C; the temperature of the oxidizing solution is 100 ° C; and the concentration is immersed in a sulfuric acid concentration having 98% by weight. The resist was stripped in the sulfuric acid solution for 5 seconds and then immersed in the oxidizing solution to strip the resist. In this case, the time for stripping the resist was 20 seconds.
Thus, although the processing time is shortened as the processing temperature (the solution temperature) increases, excessively increasing the temperature may result in components relating to the cleaning system (eg, piping lines, on/off valves, pumps for each unit) And cans, cleaning of the processing unit cover, etc.) allow for temperature and strength problems. 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 highly concentrated inorganic acid solution and the oxidizing solution. In this case, the required strength is impossible to achieve 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 highly concentrated inorganic acid solution and the oxidizing solution is not lower than 100 ° C and not higher than 110 ° C. In this case, the processing temperature (the solution temperature) can be increased more when the heat load on the cleaning system is reduced by utilizing the heat of reaction set forth above. In the case where the heat of reaction is utilized, the treatment temperature (the temperature of the solution) may be not lower than 100 ° C and not higher than 150 ° C.
A cleaning method according to this embodiment will now be explained.
Figure 7 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 electrolyzing a dilute sulfuric acid solution (step S1-1). In this case, the oxidizing substances can be efficiently produced by making the sulfuric acid concentration of the dilute sulfuric acid solution 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 solutions to not lower than 100 ° C and not higher than 110 ° C (as explained above). 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 dilute sulfuric acid solution supplied for the electrolysis.
The temperature of the highly concentrated inorganic acid solution is adjusted (step S2). Examples of the highly concentrated inorganic acid solution include, for example, a mineral acid solution having a mineral acid concentration of not less than 90% by weight. For example, a concentrated sulfuric acid solution or the like having a sulfuric acid concentration of not less than 90% by weight can be used. Although this temperature adjustment is not always necessary, it is advantageous to adjust the temperature to not less than 100 ° C and not more than 110 ° C (as explained above).
Then, the highly concentrated inorganic acid solution is supplied to the surface of the article W to be cleaned individually, sequentially or substantially simultaneously with the oxidizing solution (step S3). The supply can be performed from the dispensing unit or the like for each of the articles W to be cleaned and by sequentially immersing in the highly concentrated inorganic acid solution and the oxidizing solution. Further, for example, the supply can be performed individually, sequentially, or substantially simultaneously from the highly concentrated inorganic acid solution and the separate piping system of the oxidizing solution. So-called single wafer processing, batch processing, and the like can be used.
The treatment of supplying the highly concentrated inorganic acid solution (for example, concentrated sulfuric acid solution) to the surface of the object to be cleaned W by a specified number of times and containing an oxidizing substance (for example, electrolytic sulfuric acid produced by electrolytic dilute sulfuric acid) The treatment of supplying the oxidizing solution to the surface of the article W to be cleaned can shorten the processing time (the stripping time) to a greater extent.
In this case, it is not necessary to provide a process for supplying the rinsing liquid to the surface of the article W to be cleaned between the supply of the highly concentrated inorganic acid solution and the supply of the oxidizing solution. Therefore, the manufacturing process can be simplified and the processing time (the stripping time) can be shortened.
Figure 8 is a flow chart illustrating a cleaning method in accordance with another embodiment.
In this embodiment, the oxidizing solution and the highly concentrated inorganic acid solution 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 dilute sulfuric acid solution (step S10). In this case, the oxidizing substances can be efficiently produced by making the sulfuric acid concentration of the dilute sulfuric acid not less than 30% by weight and not more than 70% by weight.
Then, the oxidizing solution and the highly concentrated inorganic acid solution 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. Examples of the highly concentrated inorganic acid solution include a mineral acid solution having, for example, not less than 90% by weight of the inorganic acid concentration. For example, a concentrated sulfuric acid solution or the like having a sulfuric acid concentration of not less than 90% by weight can be used.
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 (as explained above). This temperature adjustment can be performed on the oxidizing solution and the highly concentrated mineral acid solution prior to mixing.
Then, the cleaning liquid (the mixture of the highly concentrated inorganic acid solution 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.
In this embodiment, as illustrated in Figures 7 and 8, the dilute sulfuric acid solution is electrolyzed. Therefore, the electrolysis efficiency is high and more oxidizing substances can be efficiently produced. In this case, the highly concentrated inorganic acid solution and the oxidizing solution are mixed after the generation of the oxidizing substances (after the electrolysis). Therefore, the electrolysis efficiency is not affected.
Further, the treatment using a highly concentrated inorganic acid solution can be carried out by using the highly concentrated inorganic acid solution, or the treatment of the surface of the article W to be cleaned can be carried out by means of a high concentration of inorganic acid.
Therefore, the treatment time (the stripping time) can be drastically shortened because the treatment (cleaning) can be performed by means of a high concentration of a mineral acid such as sulfuric acid and a large amount of an oxidizing substance.
When a high-speed operation semiconductor device is fabricated by implanting impurities at a high dose, a metamorphic layer is formed in the surface of the resist by implanting the impurity at the high dose. The resist having this altered layer is not easily stripped; and unfortunately, the desired stripping margin is not obtained.
According to this embodiment, a solution containing a highly concentrated inorganic acid and a large amount of oxidized substance can be supplied to the surface of the article W to be cleaned. Therefore, even in the case where the altered layer is formed in the resist, the strippability of the resist can be increased.
The heat of reaction can be generated by mixing the highly concentrated inorganic acid solution with an oxidizing solution which is also a low concentration inorganic acid solution before being supplied to the object to be cleaned or supplied to the object W to be cleaned. Therefore, the temperature increase of the components of the cleaning system can be suppressed; and the temperature of the mixture can be increased by To increase the reactivity of these oxidizing substances. As a result, the processing time (the stripping time) can be more shortened.
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 resist removal (stripping) can be performed quickly by using, for example, the cleaning method and cleaning system described above in the resist removal process. 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 FIG. 9, the solution used in the cleaning treatment unit 12 can be recovered by the reflux tank 63 together with contaminants and the like and then subsequently discharged to the outside of the system via the discharge conduit line 75.
This treatment can be used not only to remove resists made of organic materials, but also to similarly remove metal impurities, particles, and dry etching residues.
A robot can be provided to transport the item to be cleaned. Each of the tank 60 holding the dilute sulfuric acid solution and the tank 51 holding the highly concentrated inorganic acid solution can be connected to the line of the plant 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 quality of the rinse tank.
However, there is no need to provide for supplying a flushing fluid to the object to be cleaned between supplying the highly concentrated inorganic acid solution (for example, a concentrated sulfuric acid solution) and supplying the oxidizing solution (for example, electrolytic sulfuric acid produced by electrolytic dilute sulfuric acid). The process of the surface. The treatment of supplying the highly concentrated inorganic acid solution (for example, concentrated sulfuric acid solution) to the object to be cleaned W and the supply of the oxidizing solution containing the oxidizing substance (for example, electrolytic sulfuric acid produced by electrolytic dilute sulfuric acid) are repeatedly performed a specified number of times. The processing of the object W to be cleaned is sufficient. Therefore, the manufacturing process can be simplified and the processing time (the stripping time) can be shortened.
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 methods and systems described herein may be embodied in a variety of other forms and various modifications, substitutions and changes in the form of the methods and systems described herein are possible without departing from the spirit of the invention. 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. . . Dilute 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. . . Inorganic acid supply 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
Figure 1 is a schematic illustration of a cleaning system in accordance with an embodiment;
2A and 2B are schematic views showing a mechanism of generating an oxidizing substance;
Figure 3 is a graph showing the effect of the concentration of the oxidizing substance and the concentration of the inorganic acid on the stripping time;
Figure 4 is a graph of temperature increase due to heat of reaction;
Figure 5 is a graph showing the relationship between the stripping time and the number of sequential supplies;
Figure 6 is a graph of the effect of processing temperature (a solution temperature);
Figure 7 is a flow chart of the cleaning method;
Figure 8 is a flow chart of a cleaning method according to another embodiment; and
Figure 9 is a schematic illustration of a cleaning system in accordance with another embodiment.
5. . . Cleaning system
10. . . Sulfuric acid electrolysis unit
12. . . Cleaning unit
14. . . Solution circulation unit
15. . . Dilute 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. . . Inorganic acid supply 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 (15)

  1. A cleaning method comprising the steps of: generating an oxidizing solution containing an oxidizing substance by electrolyzing a sulfuric acid solution having a sulfuric acid concentration of 30% by weight or more and 70% by weight or less; and a sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more and the oxidizing solution; Mixing to generate heat of reaction; and cleaning the object to be cleaned by the sulfuric acid solution heated by the above reaction heat and the oxidizing solution, the article having a resist formed on the surface with a deteriorated layer, in the step of generating heat of reaction The mixing is performed on the surface of the object to be cleaned, and the step of supplying the sulfuric acid solution to the surface of the object to be cleaned and supplying the oxidizing solution after the supply of the sulfuric acid solution is repeated.
  2. The method of claim 1, wherein the oxidizing substance comprises at least one selected from the group consisting of peroxymonosulfuric acid and peroxodisulfuric acid.
  3. The method of claim 1, wherein at least one of a temperature selected from the temperature of the oxidizing solution and a sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more is not lower than 100 ° C and not higher than 110 ° C.
  4. The method of claim 1, wherein the temperature adjustment of the solution is performed by mixing the heat of reaction of the sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more with the oxidizing solution on the surface of the article to be cleaned.
  5. The method of claim 1, wherein the supplying of the flushing fluid to the surface of the article to be cleaned is not performed between the sulfuric acid solution supplying the sulfuric acid concentration of 90% by weight or more and the supplying the oxidizing solution.
  6. The method of claim 1, wherein the surface of the object to be cleaned is on the surface A resist is formed, the surface of the resist having a metamorphic layer.
  7. 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 In the cathode chamber, the sulfuric acid electrolysis unit generates an oxidizing substance in the anode chamber by electrolyzing a sulfuric acid solution having a sulfuric acid concentration of 30% by weight or more and 70% by weight or less to form an oxidizing solution containing an oxidizing substance; a dilute sulfuric acid supply unit, And supplying the sulfuric acid solution having a sulfuric acid concentration of 30% by weight or more and 70% by weight or less to the anode chamber and the cathode chamber; and a cleaning processing unit having a nozzle provided to the object to be cleaned, performing the object to be cleaned a cleaning treatment; an inorganic acid supply unit that supplies a sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more to the cleaning treatment unit; and an oxidation solution supply unit that supplies an oxidation solution containing the oxidized substance to the cleaning treatment unit, The inorganic acid supply unit and the oxidizing solution supply unit are in the object table to be cleaned The sulfuric acid solution and the oxidizing solution are mixed, and the step of supplying the sulfuric acid solution to the surface of the object to be cleaned and supplying the oxidizing solution after the sulfuric acid solution is supplied is repeated.
  8. The system of claim 7, further comprising a solution circulation unit that recovers a sulfuric acid solution selected from the cleaning treatment unit and having a sulfuric acid concentration of 90% by weight or more and the oxidation solution One less and the at least one is re-supplied to the cleaning processing unit.
  9. The system of claim 8, wherein the solution circulation unit recovers at least one selected from the group consisting of a sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more discharged from the cleaning treatment unit and the oxidizing solution, and the At least one is supplied to the cleaning processing unit.
  10. The system of claim 9, wherein the sulfuric acid electrolysis unit generates an oxidizing substance in the anode chamber by electrolyzing a dilute sulfuric acid solution and at least one selected from the group consisting of a sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more and the oxidizing solution. The dilute sulfuric acid solution is supplied from the dilute sulfuric acid supply unit, and at least one is supplied from the solution circulation unit.
  11. The system of claim 7, wherein the inorganic acid supply unit comprises a heater that performs temperature control of the sulfuric acid solution.
  12. The system of claim 8, wherein the solution circulation unit comprises a heater that performs temperature control of the oxidizing solution.
  13. The system of claim 8, wherein at least one of a conduit selected from the step of supplying the oxidizing solution to the cleaning treatment unit and a sulfuric acid solution having a sulfuric acid concentration of 90% by weight or more to the cleaning treatment unit is provided A heater is provided.
  14. The system of claim 8, 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.
  15. A method for producing a fine structure comprising cleaning an object to be cleaned by a cleaning method as claimed in claim 1 and forming a fine structure.
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