JP2017055073A - Cleaning apparatus and cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning apparatus and cleaning method, capable of achieving cost reduction.SOLUTION: The washing apparatus includes: a cleaning unit for retaining an object to be cleaned; an inorganic acid supply unit for supplying inorganic acid solution to the object to be cleaned; an oxidizability solution supply unit for supplying oxidizability solution to the object to be cleaned; and a blended waste liquid supply unit for returning, to the inorganic acid supply unit, blended waste liquid containing the inorganic acid solution recovered from the cleaning unit and the oxidizability solution recovered from the cleaning unit.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a cleaning apparatus and a cleaning method.

  A manufacturing process of various products including a semiconductor device includes a process of forming a resist pattern on a substrate. One method of cleaning the resist pattern after the resist pattern is no longer needed is a method of cleaning the substrate using a mixed solution of concentrated sulfuric acid and an oxidizing solution.

  However, when concentrated sulfuric acid and the oxidizing solution are mixed, the temperature of the mixed solution rises. In order to suppress the temperature rise of the mixed liquid, it is necessary to attach a cooling device to the cleaning device. As a result, the cost of the cleaning apparatus is increased.

JP 2010-57246 A

  The problem to be solved by the present invention is to provide a cleaning apparatus and a cleaning method that can realize cost reduction.

  The cleaning apparatus according to the embodiment includes a cleaning processing unit that holds a cleaning target, an inorganic acid supply unit that supplies an inorganic acid solution to the cleaning target, and an oxidizing property that supplies an oxidizing solution to the cleaning target. A mixed waste liquid supply unit that returns a mixed waste liquid containing a solution supply unit, the inorganic acid solution recovered from the cleaning processing unit, and the oxidizing solution recovered from the cleaning processing unit to the inorganic acid supply unit And comprising.

FIG. 1 is a schematic diagram illustrating a cleaning device according to the present embodiment. Fig.2 (a) is typical sectional drawing of a sulfuric-acid electrolysis part. FIG.2 (b) is a schematic diagram showing the AA line cross section in Fig.2 (a). FIG. 3 is a flowchart of the cleaning method according to the present embodiment.

Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same members are denoted by the same reference numerals, and the description of the members once described is omitted as appropriate.
FIG. 1 is a schematic diagram illustrating a cleaning device according to the present embodiment.

  A cleaning apparatus 5 illustrated in FIG. 1 is a cleaning apparatus that removes a resist pattern formed on a semiconductor substrate or the like, for example. The cleaning device 5 is a single wafer processing type cleaning device. The cleaning device 5 includes a sulfuric acid electrolysis unit 10, an inorganic acid supply unit 50, a cleaning processing unit 12, an oxidizing solution supply unit 13, a solution circulation unit 14, a sulfuric acid supply unit 15, and a mixed waste liquid supply unit 11. .

  The sulfuric acid electrolysis unit 10, the inorganic acid supply unit 50, the cleaning processing unit 12, the oxidizing solution supply unit 13, the solution circulation unit 14, the sulfuric acid supply unit 15, the mixed waste liquid supply unit 11, the tank 110, and the pump included in the cleaning device 5. 111, the on-off valve 112, the concentration sensor 114, the pump 120, and the on-off valve 121 are controlled by the control unit 200.

  In the sulfuric acid electrolysis unit 10, the sulfuric acid solution is electrolyzed and an oxidizing substance is generated in the anode chamber 30. Moreover, when the contaminants attached to the object to be cleaned are removed using the solution containing the oxidizing substance, the oxidizing power of the solution containing the oxidizing substance is reduced, but the sulfuric acid electrolysis unit 10 recovers the reduced oxidizing power. It has a function.

  The sulfuric acid electrolysis unit 10 includes an anode 32, a cathode 42, a diaphragm 20 provided between the anode 32 and the cathode 42, an anode chamber 30 provided between the anode 32 and the diaphragm 20, and a cathode 42. And a cathode chamber 40 provided between the diaphragm 20. An upper end sealing portion 22 is provided at the upper ends of the diaphragm 20, the anode chamber 30, and the cathode chamber 40. A lower end sealing portion 23 is provided at the lower ends of the diaphragm 20, the anode chamber 30, and the cathode chamber 40. A diaphragm 20 is provided between the anode 32 and the cathode 42. The anode 32 is supported by the anode support 33. The cathode 42 is supported by a cathode support 43. A DC power supply 26 is connected to the anode 32 and the cathode 42.

  The anode 32 includes a conductive anode substrate 34 and an anode conductive film 35 formed on the surface of the anode substrate 34. The anode substrate 34 is supported on the inner surface of the anode support 33, and the anode conductive film 35 faces the anode chamber 30.

  The cathode 42 includes a cathode base 44 having conductivity and a cathode conductive film 45 formed on the surface of the cathode base 44. The cathode substrate 44 is supported on the inner surface of the cathode support 43, and the cathode conductive film 45 faces the cathode chamber 40.

  An anode inlet portion 19 is provided at the lower end side of the anode chamber 30, and an anode outlet portion 17 is provided at the upper end side. The anode inlet portion 19 and the anode outlet portion 17 communicate with the anode chamber 30. A cathode inlet portion 18 is formed on the lower end side of the cathode chamber 40, and a cathode outlet portion 16 is formed on the upper end side. The cathode inlet portion 18 and the cathode outlet portion 16 communicate with the cathode chamber 40.

  The inorganic acid supply unit 50 includes a tank 51 that stores a high-concentration inorganic acid solution, a pump 52, and an on-off valve 71. The inorganic acid supply unit 50 can supply an inorganic acid solution to the cleaning object W. The tank 51, the pump 52, and the on-off valve 71 are connected to the nozzle 61 through the pipe line 53. The high-concentration inorganic acid solution stored in the tank 51 is supplied to the nozzle 61 via the pipe line 53 by the operation of the pump 52. The inorganic acid supply unit 50 has a function of supplying a high-concentration inorganic acid solution stored in the tank 51 to the nozzle 61 of the cleaning processing unit 12. Thereby, the high-concentration inorganic acid solution supplied to the nozzle 61 is supplied to the surface of the cleaning object W. The highly concentrated inorganic acid solution preferably has a dehydrating action. For example, a concentrated sulfuric acid solution having a sulfuric acid concentration of 90 weight percent or more is exemplified as the high concentration inorganic acid solution. The tank 51 can be provided with a heater to control the temperature of the highly concentrated inorganic acid solution.

  A cleaning object W is installed in the cleaning processing unit 12, and the cleaning object W is cleaned with a cleaning solution. The cleaning processing unit 12 includes a nozzle 61, a rotary table 62, and a cover 29. As the cleaning solution, an oxidizing solution containing an oxidizing substance (oxidation active species) obtained in the sulfuric acid electrolysis unit 10 and a high-concentration inorganic acid solution supplied from the inorganic acid supply unit 50 are used. . The object to be cleaned is held on the rotary table 62 of the cleaning processing unit 12. Then, the oxidizing solution and the inorganic acid solution are poured onto the cleaning object W via the nozzle 61.

  The oxidizing solution obtained in the sulfuric acid electrolysis unit 10 is supplied to the nozzle 61 provided in the cleaning processing unit 12 via the oxidizing solution supply unit 13. Further, a high-concentration inorganic acid solution is supplied from the inorganic acid supply unit 50 to the nozzle 61 provided in the cleaning processing unit 12. The oxidizing solution and the high-concentration inorganic acid solution are sequentially supplied, or the oxidizing solution and the high-concentration inorganic acid solution are supplied almost simultaneously.

  For example, an oxidizing solution and a high-concentration inorganic acid solution can be mixed, and the mixed solution (cleaning solution) can be supplied to the cleaning processing unit 12. When the high-concentration inorganic acid solution supplied from the inorganic acid supply unit 50 and the oxidizing solution supplied from the sulfuric acid electrolysis unit 10 are supplied to the pipeline 74 almost simultaneously, the pipeline 74 is used for both solutions. It becomes a mixing part which mixes. In addition to the pipe line 74 and the nozzle 61, a pipe line and a nozzle (not shown) are provided, and a high-concentration inorganic acid solution is cleaned from a pipe system different from a solution containing an oxidizing substance (oxidizing solution). It can also be made to supply.

  Further, a tank (not shown) may be provided to mix the oxidizing solution and the high concentration inorganic acid solution. In this case, a tank (not shown) serves as the mixing unit. If a tank (not shown) is provided, it is possible to buffer the quantitative fluctuation of the mixed liquid (cleaning liquid) and to adjust the composition. In addition, a heater can be provided in a tank or pipe 74 (not shown) to control the temperature of the mixed liquid (cleaning liquid).

  The nozzle 61 has a discharge port for discharging an oxidizing solution, a high-concentration inorganic acid solution, and a mixed solution (cleaning solution) of the oxidizing solution and the high-concentration inorganic acid solution to the object to be cleaned W. In addition, a rotary table 62 on which the cleaning object W is placed is provided so as to face the discharge port. The rotary table 62 is provided inside the cover 29. Then, the cleaning target W is discharged by discharging the oxidizing solution, the high-concentration inorganic acid solution, and the mixed solution (cleaning liquid) of the oxidizing solution and the high-concentration inorganic acid solution from the nozzle 61 toward the cleaning target W. The upper contaminants and unnecessary materials (for example, resist) are removed in a short time. The removal of contaminants and unnecessary materials (for example, resist) on the cleaning target W in a short time will be described later.

  The oxidizing solution generated in the sulfuric acid electrolysis unit 10 is supplied from the anode outlet unit 17 to the cleaning processing unit 12 via the oxidizing solution supply unit 13. The oxidizing solution supply unit 13 includes an on-off valve 73a, a tank 28, a pump 81, an on-off valve 74a, and a pipe line 74. The oxidizing solution supply unit 13 can supply the oxidizing solution to the cleaning object W.

  The anode outlet part 17 is connected to a tank 28 as a solution holding part via a pipe line 73 provided with an on-off valve 73a. The tank 28 is connected to the nozzle 61 via a pipe line 74. The oxidizing solution stored in the tank 28 is supplied to the nozzle 61 via the pipe line 74 by the operation of the pump 81. In the pipe line 74, an opening / closing valve 74 a is provided on the discharge side of the pump 81. By storing and holding the oxidizing solution in the tank 28, it is possible to buffer the quantitative variation of the oxidizing solution generated in the sulfuric acid electrolysis unit 10. The tank 28 may be provided with a heater to control the temperature of the oxidizing solution.

  The solution circulation unit 14 includes a recovery tank 63, a filter 64, a pump 82, and on-off valves 76 and 91. The oxidizing solution discharged from the cleaning processing unit 12 is recovered by the solution circulation unit 14 and can be supplied to the cleaning processing unit 12 again. For example, the oxidizing solution discharged from the cleaning processing unit 12 can pass through the recovery tank 63, the filter 64, the pump 82, and the on-off valve 76 in this order, and can be supplied to the anode inlet 19 of the sulfuric acid electrolysis unit 10. ing. That is, the oxidizing solution is circulated between the sulfuric acid electrolysis unit 10 and the cleaning processing unit 12. In such a case, the oxidizing solution used for the cleaning treatment is supplied to the sulfuric acid electrolysis unit 10 as necessary, and then the sulfuric acid electrolysis unit 10 is electrolyzed to obtain an oxidizing solution containing an oxidizing substance. The oxidizing solution can be supplied to the cleaning processing unit 12 through the tank 28 or the like.

  If necessary, the used oxidizing solution is supplied to the sulfuric acid electrolysis unit 10, and diluted sulfuric acid is also supplied from the sulfuric acid supply unit 15 to the sulfuric acid electrolysis unit 10 to perform electrolysis, thereby producing an oxidizing solution. Can be generated. The oxidizing solution obtained here can be supplied to the cleaning processing unit 12 via the tank 28 or the like. Such reuse of the oxidizing solution can be repeated as much as possible, and in the cleaning process of the cleaning object W, it is possible to reduce the amount of materials (chemicals, etc.) and waste liquid required for generating the oxidizing solution. It becomes.

  The filter 64 has a function of filtering contaminants and unnecessary substances (for example, a resist) contained in the oxidizing solution, the inorganic acid solution, and the mixed solution (in the cleaning solution) discharged from the cleaning processing unit 12.

  Alternatively, the oxidizing solution discharged from the cleaning processing unit 12 passes through the recovery tank 63, the filter 64, the pump 82, and the on-off valve 91 in this order, and is supplied to the tank 28 without passing through the sulfuric acid electrolysis unit 10. It can also be possible. In such a case, the used oxidizing solution can be reused in the cleaning process. Such reuse of the oxidizing solution can be repeated as much as possible, and the amount of materials (chemicals, etc.) and waste liquid required for generating the oxidizing solution can be reduced.

  In addition, the high-concentration inorganic acid solution discharged from the cleaning processing unit 12 and the mixed solution (cleaning solution) of the oxidizing solution and the high-concentration inorganic acid solution can be circulated and reused in the same manner. In particular, when the inorganic acid is sulfuric acid, it becomes a raw material solution for the oxidizing solution, so the amount of diluted sulfuric acid supplied from the sulfuric acid supply unit 15 can be reduced. In addition, when a problem arises in reuse when the inorganic acid solution and the oxidizing solution are mixed, a recovery tank or an open / close valve (not shown) for the inorganic acid solution is connected to the cleaning processing unit 12 to connect the inorganic acid solution. And the oxidizing solution can be separated and recovered. In this case, if the inorganic acid solution and the oxidizing solution are sequentially supplied, separation and recovery can be performed at the time of each supply. Each can be reused separately, for example, by reprocessing.

  The recovery tank 63 is provided with a discharge pipe 75 and a discharge valve 75a, and has a function of discharging contaminants and unnecessary materials (for example, resists) removed by the cleaning processing unit 12 to the outside of the system. Yes.

  The sulfuric acid supply unit 15 has a function of supplying a diluted 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 a diluted sulfuric acid solution to the anode chamber 30 and the cathode chamber 40, a tank 60 that stores diluted sulfuric acid, open / close valves 70 and 72, and a pipe 85. .

  The tank 60 stores a diluted sulfuric acid solution having a sulfuric acid concentration of 30 weight percent or more and 70 weight percent or less. The dilute sulfuric acid solution in the tank 60 is supplied to the anode chamber 30 through the on-off valve 70 and the anode inlet 19 through a pipe line on the downstream side of the on-off valve 76 when the pump 80 is driven. Further, the diluted sulfuric acid solution in the tank 60 is supplied to the cathode chamber 40 through the opening / closing valve 72 and the pipe 86 on the downstream side of the opening / closing valve 72 and the cathode inlet portion 18 by driving the pump 80. The

  In this embodiment, since the sulfuric acid concentration of the solution supplied to the cathode side is low, it is possible to suppress the diaphragm 20 from being damaged by the electrolysis of sulfuric acid. That is, in the sulfuric acid electrolysis reaction, water on the cathode side moves to the anode side, the sulfuric acid concentration of the solution on the cathode side increases, and the diaphragm 20 tends to deteriorate. Moreover, when an ion exchange membrane is used for the diaphragm 20, in the concentrated sulfuric acid, the resistance of the ion exchange membrane increases as the water content decreases, and there arises a problem that the cell voltage increases. Therefore, in order to alleviate this problem, it is possible to suppress an increase in resistance by supplying diluted sulfuric acid to the cathode side and supplying water to the ion exchange membrane.

  Further, if the concentration of sulfuric acid supplied to the sulfuric acid electrolysis unit 10 is lowered, the production efficiency of oxidizing substances (for example, peroxomonosulfuric acid and peroxodisulfuric acid) contained in the oxidizing solution is improved.

  The material of the cover 29 in the anode support 33, the cathode support 43, the cathode outlet part 16, the anode outlet part 17, the cathode inlet part 18, the anode inlet part 19, and the cleaning processing part 12 is, for example, from the viewpoint of chemical resistance. Fluorine resin such as polytetrafluoroethylene is used.

  In addition, a fluororesin in which a heat insulating material is wound on a pipe for supplying an oxidizing solution, a high-concentration inorganic acid solution, and a mixed solution (cleaning solution) of the oxidizing solution and the high-concentration inorganic acid solution in the cleaning processing unit 12 A tube or the like can be used. This pipe can be provided with an in-line heater made of a fluorine-based resin. Bellows pumps made of fluororesin with heat resistance and chemical resistance are used for pumps that send oxidizing solutions, highly concentrated inorganic acid solutions, and mixed solutions (cleaning solutions) of oxidizing solutions and highly concentrated inorganic acid solutions. Can be used.

  For example, quartz can be used as the material of each tank for storing the sulfuric acid solution. Furthermore, an overflow device, a temperature control device, and the like can be appropriately provided in these tanks.

  As the diaphragm 20, for example, a neutral membrane including a PTFE porous membrane such as the product name POREFLON (however, hydrophilized), or a cation exchange membrane such as the product name Nafion, Aciplex, Flemion, etc. Can do. The dimension of the diaphragm 20 is about 50 square centimeters, for example. As the upper end sealing part 22 and the lower end sealing part 23, for example, an O-ring coated with a fluorine-based resin may be used.

  For example, p-type silicon or a valve metal such as niobium can be used as the material of the anode conductive substrate 34. Here, the valve metal means that the metal surface is uniformly covered with the oxide film by anodic oxidation and has excellent corrosion resistance. For the cathode conductive substrate 44, for example, n-type silicon can be used.

  As a material for the anode conductive film 35 and the cathode conductive film 45, for example, glassy carbon can be used. When a solution having a relatively high sulfuric acid concentration is supplied, a conductive diamond film is preferably used from the viewpoint of durability.

  For both the anode and the cathode, the conductive film and the substrate may be the same material. For example, when glassy carbon is used for the cathode substrate or when a conductive diamond free-standing film is used for the anode substrate, the substrate itself becomes a conductive film having electrocatalytic properties and can contribute to the electrolytic reaction. A diamond film is formed using a hot filament-CVD (HF-CVD) method while supplying boron gas or nitrogen gas to obtain a conductive diamond film. This conductive diamond film has a wide “potential window” of, for example, 3 to 5 volts, and an electrical resistance of, for example, 5 to 100 milliohm centimeters.

  Here, the “potential window” is the minimum potential (1.2 volts or more) required for electrolysis of water. This “potential window” varies depending on the material. When electrolysis is performed at a potential in the “potential window” using a material with a wide “potential window”, the electrolytic reaction having a redox potential in the “potential window” proceeds in preference to the electrolysis of water. In some cases, an oxidation reaction or a reduction reaction of a substance that is difficult to be electrolyzed proceeds preferentially. Therefore, by using such conductive diamond, it becomes possible to decompose and synthesize substances that were impossible with conventional electrochemical reactions.

  In the HF-CVD method, a source gas is supplied to a tungsten filament in a high temperature state to decompose the source gas. Thereby, radicals necessary for film growth are formed. Thereafter, a film is formed by reacting radicals diffused on the substrate surface with another reactive gas on a desired substrate.

  The mixed waste liquid supply unit 11 can return the mixed waste liquid containing the inorganic acid solution recovered from the cleaning processing unit 12 and the oxidizing solution recovered from the cleaning processing unit 12 to the inorganic acid supply unit 50 again. . A part of the mixed waste liquid may be supplied to the sulfuric acid electrolysis unit 10.

  For example, the mixed waste liquid supply unit 11 includes a pump 102, a filter 101, and an on-off valve 103. The mixed waste liquid collected in the collection tank 63 can be returned again to the inorganic acid supply unit 50 via the pipe line 104, the filter 101, the pump 102, the on-off valve 103, and the pipe line 100. For example, the mixed waste liquid in the recovery tank 63 passes through the filter 101 and the on-off valve 103 by driving the pump 102, and is supplied to the tank 51 via the pipe line 100 on the downstream side of the on-off valve 103. Thereafter, the mixed waste liquid is reused as a cleaning solution. Note that the filter 101 has a function of filtering contaminants and unnecessary substances (for example, a resist) in the mixed waste liquid. The temperature of the mixed waste liquid before being returned again to the inorganic acid supply unit 50 is, for example, 60 ° C. or higher.

  Further, the cleaning device 5 includes a tank 110 for replenishing the inorganic acid solution to the inorganic acid supply unit 50. In the tank 110, an inorganic acid solution having a concentration different from that of the inorganic acid solution stored in the tank 51 is stored. For example, an inorganic acid solution having a higher concentration than the inorganic acid solution stored in the tank 51 is stored in the tank 110. The inorganic acid solution in the tank 51 passes through the on-off valve 112 and is supplied to the tank 51 via the pipe line 113 on the downstream side of the on-off valve 112 when the pump 111 is driven.

  For example, the concentration of the inorganic acid in the inorganic acid solution in the tank 51 is measured by the concentration sensor 114. The concentration is transmitted to the control unit 200. In the cleaning device 5, a new inorganic acid solution is replenished from the tank 110 to the inorganic acid supply unit 50 according to the concentration of the inorganic acid solution in the inorganic acid supply unit 50. Further, the inorganic acid solution is discharged from the inorganic acid supply unit 50 according to the concentration of the inorganic acid solution in the inorganic acid supply unit 50. For example, when the pump 120 is driven, the inorganic acid solution is discharged from the inorganic acid supply unit 50 via the on-off valve 103. Thereby, the density | concentration of the inorganic acid of the inorganic acid solution in the tank 51 is maintained at a desired density | concentration. This desired density is controlled by the control unit 200.

  In addition, the control unit 200 performs the cleaning according to the concentration of the oxidizing active species in the mixed solution including the inorganic acid solution supplied to the cleaning target W and the oxidizing solution supplied to the cleaning target W. Control is performed to change the flow rate ratio between the inorganic acid solution and the oxidizing solution supplied to the product.

  In the present embodiment, the on-off valves 70, 71, 72, 73a, 74a, 75a, 76, 91, 103, 112, 121 also have a function of controlling the flow rates of various solutions. The pumps 80, 81, 82, 102, 111, and 120 also have a function of controlling the flow rates of various solutions.

  An example of the action of the cleaning device 5 will be described.

  Fig.2 (a) is typical sectional drawing of a sulfuric-acid electrolysis part. FIG.2 (b) is a schematic diagram showing the AA line cross section in Fig.2 (a). 2A and 2B schematically illustrate the generation mechanism of the oxidizing substance.

  As shown in FIGS. 2A and 2B, the anode 32 and the cathode 42 face each other with the diaphragm 20 in between. The anode 32 is supported by an anode support 33 with the anode conductive film 35 facing the anode chamber 30. The cathode 42 is supported by a cathode support 43 with the cathode conductive film 45 facing the cathode chamber 40. Electrolytic unit casings 24 are provided at both ends of the diaphragm 20, the anode support 33, and the cathode support 43, respectively.

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

  Furthermore, a part of the mixed waste liquid can also be supplied to the anode chamber 30 from the solution circulation section 14 via the anode inlet section 19. For example, a part of the mixed waste liquid can also be supplied from the solution circulation unit 14 to the cathode chamber 40 via the cathode inlet unit 18.

  When a positive voltage is applied to the anode 32 and a negative voltage is applied to the cathode 42, an electrolysis reaction occurs in each of the anode chamber 30 and the cathode chamber 40. In the anode chamber 30, reactions represented by chemical formula (1), chemical formula (2), and chemical formula (3) occur.

^{_{2HSO 4 - → S 2 O 8}} 2- 2H + + 2e - ·· (1)
HSO ₄ ⁻ + H ₂ O → HSO ₅ ⁻ + 2H ⁺ + 2e ⁻ (2)
2H ₂ O → 4H ⁺ + 4e ⁻ + O ² .. (3)
Here, water (H ₂ O) in the chemical formulas (2) and (3) is 30 percent water contained in a 70 weight percent sulfuric acid solution. In the anode chamber 30, peroxomonosulfate ions (HSO ₅ ⁻ ) are generated by the reaction of the chemical formula (2). Further, the elementary reactions of the chemical formula (1) and the chemical formula (3) cause a total reaction as shown in the chemical formula (4), and a reaction in which peroxomonosulfate ions (HSO ₅ ⁻ ) and sulfuric acid are generated. Peroxomonosulfuric acid has a stronger detergency than sulfuric acid.

Alternatively, as shown in the chemical formula (5), hydrogen peroxide (H ₂ O ₂ ) is generated from the elementary reaction of the chemical formulas (1) and (3), and then the peroxomonosulfate ion (HSO) of the chemical formula (4) is formed. ₅ ^-) in some cases it is produced. Further, the reaction of formula (1), in some cases peroxodisulfate _{(H 2} S _{2 O 8)} is generated. Chemical formula (4) and chemical formula (5) represent a secondary reaction from chemical formula (1).

S ₂ O ₈ ²⁻ + H ⁺ + H ₂ O → HSO ₅ ⁻ + H ₂ SO ₄ .. (4)
S ₂ O ₈ ²⁻ + H ⁺ + H ₂ O → H ₂ O ₂ + H ₂ SO ₄ .. (5)
In the cathode chamber 40, hydrogen gas is generated as represented by chemical formula (6). This is because hydrogen ions (H ⁺ ) generated at the anode move to the cathode via the diaphragm 20 and an electrolysis reaction occurs. Hydrogen gas is discharged from the cathode chamber 40 via the cathode outlet portion 16.

2H ⁻ + 2e ⁻ → H ₂ ... (6)
In the present embodiment, as represented by the chemical formula (7), by oxidizing the sulfuric acid solution, for example, oxidation of peroxomonosulfuric acid (H ₂ SO ₅ ), peroxodisulfuric acid (H ₂ S ₂ O ₈ ), etc. An oxidative solution containing the same can be obtained. In addition, although hydrogen gas is produced | generated as a by-product, this hydrogen gas does not affect peeling of a resist etc.

H ₂ SO ₄ + H ₂ O → oxidizing substance + H ₂ .. (7)
The reaction rate between organic substances such as resist and peroxomonosulfuric acid is fast. Thereby, even when the amount of resist is relatively large, the peeling is performed in a short time. In addition, when peroxomonosulfuric acid is used, it can be peeled off at a low temperature, so that it is not necessary to adjust the temperature to suppress the temperature rise. Further, since the sulfuric acid electrolysis unit 10 can stably produce a large amount of peroxomonosulfuric acid, the reaction rate with the object to be removed can be increased at a low temperature.

  Here, in order to shorten the processing time and improve the production efficiency, the amount of the oxidizing substance may be increased. In this case, if the size of the apparatus is increased, the applied power is increased, or the amount of dilute sulfuric acid solution is increased, the amount of the generated oxidizing substance can be increased. However, doing so will also increase production costs and environmental impact. Therefore, it is necessary to improve the electrolytic efficiency and efficiently generate the oxidizing substance.

  According to the knowledge obtained by the present inventors, when the electrolysis parameters (for example, the amount of electricity, the flow rate, the temperature, etc.) are made constant, the more the oxidizing substance is generated, the lower the sulfuric acid concentration during electrolysis. it can. Therefore, if the sulfuric acid concentration supplied to the sulfuric acid electrolysis unit 10 is lowered, the generation efficiency of the oxidizing substances (for example, peroxomonosulfuric acid and peroxodisulfuric acid) contained in the oxidizing solution is improved.

  Further, according to other knowledge obtained by the present inventors, the treatment time becomes longer as the concentration of inorganic acid such as sulfuric acid is lower in the removal and removal of organic substances such as resist.

  That is, the lower the concentration of sulfuric acid, the more oxidizing material can be produced at the stage of producing the oxidizing substance, but the sulfuric acid concentration can be increased even if the amount of oxidizing substance is the same at the stage of stripping. The higher the value, the shorter the peeling time.

  Therefore, in the present embodiment, as an example, a diluted sulfuric acid solution having a sulfuric acid concentration of 30 weight percent or more and 70 weight percent or less is supplied to the sulfuric acid electrolysis unit 10. Further, as an example, a concentrated sulfuric acid solution having a sulfuric acid concentration of 90 weight percent or more is supplied from the inorganic acid supply unit 50 to the surface of the cleaning object W without using the sulfuric acid electrolysis unit 10.

  Thereby, the electrolytic efficiency in the sulfuric acid electrolysis part 10 can be improved, and more oxidizing substances can be produced | generated. In addition, a high concentration inorganic acid can be supplied to the surface of the cleaning object W without affecting the electrolysis efficiency in the sulfuric acid electrolysis unit 10. As a result, a solution having a high concentration of an inorganic acid such as sulfuric acid and a large amount of an oxidizing substance can be supplied to the surface of the cleaning object W, so that the processing time can be greatly shortened.

  Furthermore, when a high-concentration inorganic acid solution and an oxidizing solution that is also a low-concentration inorganic acid solution are mixed, heat of reaction is generated. In this embodiment, this reaction heat is utilized. If the temperature is increased, the reactivity of the oxidizing substance contained in the oxidizing solution can be increased, so that the processing time can be shortened. In addition, before mixing a high concentration inorganic acid solution and an oxidizing solution, you may heat a high concentration inorganic acid solution previously.

  However, if the solution temperature in the sulfuric acid electrolysis unit 10 or the inorganic acid supply unit 50 is increased, the heat-resistant temperature and strength of each component (for example, pipes, open / close valves, pumps, tanks, covers of the cleaning processing unit, etc.) May be a problem. In order to improve chemical resistance, a portion that comes into contact with a high concentration inorganic acid solution or oxidizing solution is often formed of, for example, a fluorine resin. In such a case, if the temperature is too high, the required strength may not be obtained.

  According to this embodiment, the reaction is performed by mixing a high concentration inorganic acid solution and an oxidizing solution that is also a low concentration inorganic acid solution before being supplied to the cleaning target W or on the cleaning target W. It generates heat. Therefore, while the temperature rise of each component can be suppressed, the reactivity of an oxidizing substance can be improved by raising the temperature of the mixed liquid.

  Here, most of the mixed waste liquid can be supplied to the sulfuric acid electrolysis unit 10 and most of the mixed waste liquid can be reused as a solution for generating an oxidizing substance. However, in order to efficiently generate an oxidizing substance in the sulfuric acid electrolysis unit 10, it is necessary to supply a low-temperature sulfuric acid solution to the sulfuric acid electrolysis unit 10. That is, the mixed waste liquid that has once become high temperature needs to be cooled before being supplied to the sulfuric acid electrolysis unit 10. That is, in a system in which most of the mixed waste liquid is reused as a solution for generating an oxidizing substance, an incidental facility for cooling the mixed waste liquid supplied to the sulfuric acid electrolysis unit 10 is required. However, if ancillary facilities are attached to the cleaning device 5, an increase in production costs and an environmental load are caused.

  On the other hand, in this embodiment, the mixed waste liquid collected in the collection tank 63 is reused as a cleaning solution. Thereby, the incidental equipment which cools the mixed waste liquid supplied to the sulfuric acid electrolysis part 10 becomes unnecessary. As a result, an increase in production cost and an environmental load can be suppressed.

  Moreover, the temperature of the mixed waste liquid before returning again to the inorganic acid supply part 50 is 60 degreeC or more, for example. Thereby, a high temperature inorganic acid solution is stored in the tank 51. As a result, in addition to the heat of reaction, the temperature of the inorganic acid solution in the tank 51 also contributes to the reaction rate when removing the resist from the cleaning object W. Thereby, the incidental equipment which heats the tank 51 becomes unnecessary. Or the incidental equipment which heats the tank 51 is enough for a small equipment. As a result, an increase in production cost and an environmental load can be suppressed.

  Further, even if a part of the mixed waste liquid is supplied to the sulfuric acid electrolysis unit 10, the amount of the mixed waste liquid supplied to the sulfuric acid electrolysis unit 10 is smaller than when almost all of the mixed waste liquid is supplied to the sulfuric acid electrolysis unit 10. Thereby, the incidental equipment for cooling the mixed waste liquid is sufficient with a small equipment. Thereby, an increase in production cost and an increase in environmental load can be suppressed.

  In the present embodiment, the inorganic acid supply unit 50 is provided with a tank 110 for replenishing a high-concentration inorganic acid solution. Furthermore, the inorganic acid solution in the tank 51 of the inorganic acid supply unit 50 can be discarded by the pump 120. As a result, even if the mixed waste liquid is supplied to the inorganic acid supply unit 50 and the concentration of the inorganic acid solution in the tank 51 changes, the concentration of the inorganic acid solution in the tank 51 can be set to a desired value by the management by the concentration sensor 114. Concentration (eg, 90 weight percent or more) is maintained.

  In the present embodiment, the concentration of oxidizing active species in the mixed solution including the inorganic acid solution supplied to the cleaning target W and the oxidizing solution supplied to the cleaning target W by the control unit 200. Accordingly, the flow rate ratio between the inorganic acid solution and the oxidizing solution supplied to the cleaning object W is controlled. As a result, even if the mixed waste liquid is reused as the cleaning solution, the flow rate ratio between the inorganic acid solution and the oxidizing solution supplied to the cleaning target W is controlled to a desired flow rate ratio.

  The cleaning method using the cleaning apparatus 5 described above is shown in FIG. FIG. 3 is a flowchart of the cleaning method according to the present embodiment.

  For example, the inorganic acid solution and the oxidizing solution are supplied individually or simultaneously to the cleaning object W (step S10). Next, after the inorganic acid solution and the cleaning processing unit are supplied to the object to be cleaned, the mixed waste liquid containing the inorganic acid solution and the cleaning processing unit is collected and mixed with the inorganic acid solution (step S20). That is, the mixed waste liquid is returned to the inorganic acid supply unit 50 again, and the mixed waste liquid is reused as a cleaning solution for cleaning the cleaning object W. Here, the temperature of the mixed waste liquid before mixing with the inorganic acid solution is 60 ° C. or higher.

  Further, a new inorganic acid solution having a concentration different from that of the inorganic acid solution is replenished according to the concentration of the inorganic acid solution. Further, the inorganic acid solution is discarded according to the concentration of the inorganic acid solution. Thereby, the density | concentration of an inorganic acid solution is maintained by the desired density | concentration (for example, 90 weight% or more).

  Moreover, according to the density | concentration of the oxidation active species in the mixed solution containing the inorganic acid solution supplied to the cleaning target W, and the oxidizing solution supplied to the cleaning target W, the inorganic acid solution and the oxidizing solution And the flow ratio is changed. Thereby, even if the mixed waste liquid is reused as a cleaning solution for cleaning the cleaning object W, the flow ratio of the inorganic acid solution and the oxidizing solution supplied to the cleaning object W is controlled to a desired flow ratio. . Further, an oxidizing substance may be generated by electrolyzing a part of the mixed waste liquid.

  The embodiment has been described above with reference to specific examples. However, the embodiments are not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the embodiments as long as they include the features of the embodiments. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

  In addition, each element included in each of the above-described embodiments can be combined as long as technically possible, and combinations thereof are also included in the scope of the embodiment as long as they include the features of the embodiment. In addition, in the category of the idea of the embodiment, those skilled in the art can conceive various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the embodiment. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 5 Cleaning apparatus, 10 Sulfuric acid electrolysis part, 11 Mixed waste liquid supply part, 12 Cleaning process part, 13 Oxidizing solution supply part, 14 Solution circulation part, 15 Sulfuric acid supply part, 16 Cathode outlet part, 17 Anode outlet part, 18 Cathode inlet Part, 19 anode inlet part, 20 diaphragm, 22 upper end sealing part, 23 lower end sealing part, 24 electrolysis part housing, 26 DC power supply, 28, 51, 60, 110 tank, 29 cover, 30 anode chamber, 32 anode 33 Anode support, 34 Anode base, 35 Anode conductive film, 40 Cathode chamber, 42 Cathode, 43 Cathode support, 44 Cathode base, 45 Cathode conductive film, 50 Inorganic acid supply section, 52, 80, 81, 82, 102, 111, 120 Pump, 53, 73, 74, 85, 86, 100, 104, 113 Pipe line, 61 Nozzle, 62 Rotary table, 63 Collection tank, 64, 01 filter, 70,71,72,73a, 74a, 76,91,103,112,121 off valve 75 discharge line, 75a discharge valve, 114 concentration sensor, 200 control unit

Claims (10)

A cleaning processing section for holding a cleaning object;
An inorganic acid supply unit for supplying an inorganic acid solution to the object to be cleaned;
An oxidizing solution supply unit for supplying an oxidizing solution to the object to be cleaned;
A mixed waste liquid supply unit that returns a mixed waste liquid containing the inorganic acid solution recovered from the cleaning processing unit and the oxidizing solution recovered from the cleaning processing unit to the inorganic acid supply unit;
Cleaning device equipped with.   The cleaning apparatus according to claim 1, wherein the temperature of the mixed waste liquid before returning to the inorganic acid supply unit is 60 ° C. or higher. A tank that replenishes the inorganic acid supply unit with an inorganic acid solution having a concentration different from that of the inorganic acid solution according to the concentration of the inorganic acid solution in the inorganic acid supply unit;
The cleaning apparatus according to claim 1, further comprising a pump that discharges the inorganic acid solution from the inorganic acid supply unit according to a concentration of the inorganic acid solution in the inorganic acid supply unit. The oxidizing solution includes an oxidizing active species,
The inorganic acid solution supplied to the cleaning target and the oxidizing solution supplied to the cleaning target are supplied to the cleaning target according to the concentration of the oxidizing active species in the mixed solution. The cleaning apparatus according to claim 1, further comprising a control unit that changes a flow ratio of the inorganic acid solution to be oxidized and the oxidizing solution. An anode, a cathode, a diaphragm provided between the anode and the cathode, an anode chamber provided between the anode and the diaphragm, and a cathode provided between the cathode and the diaphragm A sulfuric acid electrolysis unit that electrolyzes the sulfuric acid solution and generates an oxidizing substance in the anode chamber,
The cleaning apparatus according to claim 1, wherein a part of the mixed waste liquid is supplied to the sulfuric acid electrolysis unit. Supplying the inorganic acid solution and the oxidizing solution individually or simultaneously to the object to be cleaned;
After the inorganic acid solution and the cleaning processing unit are supplied to the object to be cleaned, the mixed waste liquid containing the inorganic acid solution and the cleaning processing unit is collected, and the mixed solution is mixed with the inorganic acid solution. Steps,
Cleaning method with.   The cleaning method according to claim 6, wherein the temperature of the mixed waste liquid before being mixed with the inorganic acid solution is 60 ° C. or higher.   The inorganic acid solution having a different concentration from the inorganic acid solution is replenished according to the concentration of the inorganic acid solution, or the inorganic acid solution is discarded according to the concentration of the inorganic acid solution. The cleaning method according to 1. The oxidizing solution includes an oxidizing active species,
The inorganic acid solution and the inorganic acid solution supplied to the object to be cleaned and the oxidizing solution supplied to the object to be cleaned according to the concentration of the oxidizing active species in a mixed solution. The cleaning method according to claim 6, wherein a flow rate ratio with the oxidizing solution is changed.   The cleaning method according to claim 9, wherein the oxidizing substance is generated by electrolyzing a part of the mixed waste liquid.

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