JP2006303115A - Cleaning equipment, cleaning method and semiconductor fabrication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide cleaning equipment in which a circuit pattern on the surface of a substrate can be prevented from corroding in a cleaning process using pure water. <P>SOLUTION: The cleaning equipment comprises two cleaning tubs 3 and 4 for cleaning a substrate stepwise, a first circulation path for circulating a used cleaning liquid from a cleaning tub 3 other than that on a final stage to a cleaning tub 3 other than that on the final stage, an ozone passing section 10 for regenerating the used cleaning liquid in a cleaning tub 3 other than that on the final stage by making ozone pass and returning the regenerated cleaning liquid back to a cleaning tub other than that on the final stage, and a second circulation path including supply pipes 26 and 28 for circulating the cleaning liquid used in a cleaning tub on the final stage to the final stage without making ozone pass. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cleaning apparatus, a cleaning method, and a semiconductor manufacturing apparatus for cleaning a glass substrate and a wafer to remove an organic film such as a resist in a manufacturing process of a liquid crystal panel, a PDP (plasma display panel) or a semiconductor.

  In general, a large amount of various cleaning liquids such as sulfuric acid and hydrogen peroxide are used in a cleaning process for removing or removing a resist in a process of manufacturing a liquid crystal panel or a semiconductor. Therefore, a large amount of waste liquid such as waste acid and waste alkali is generated, and the treatment of the waste liquid becomes a problem. As for the types of cleaning liquids that are used in large quantities, they have been collected and purified, and have been tried to be reused in manufacturing processes, etc., and various methods for regenerating cleaning liquids have been developed.

  In recent years, the size of the cleaning tank used has increased due to the increase in the size of the panel and the increase in the diameter of the wafer, and the capacity thereof has increased. Along with this, the amount of cleaning liquid used increases, which increases not only the cost of the cleaning liquid but also the processing cost and environmental burden of the cleaning liquid. For this reason, a new technique for reducing the amount of waste liquid as much as possible is required.

  For example, Patent Document 1 and Patent Document 2 are prior art documents of a cleaning apparatus having a cleaning liquid regeneration function.

  FIG. 10 is a diagram illustrating a configuration of the cleaning apparatus disclosed in Patent Document 1 and Patent Document 2. In FIG. In the figure, the regenerator 533 regenerates by passing ozone through the cleaning liquid after the cleaning of the first cleaning tank 519 out of two cleaning tanks. The regenerated cleaning liquid is supplied to the nozzle pipe 540 above the second cleaning tank 520 by the pump 535 and used as the cleaning liquid in the second cleaning tank 520. The cleaning liquid after cleaning in the second cleaning tank 520 is supplied from the recovery tank 522 to the nozzle pipe 529 by the pump 524 and used as the cleaning liquid in the first cleaning tank 519. This cleaning solution contains either ethylene carbonate or propylene carbonate, and has a characteristic that the resist stripping rate is extremely high as compared with the conventional cleaning solution. In addition, this cleaning solution has a high regeneration capability by ozone ventilation. That is, the reproducing apparatus 533 decomposes the organic substance (resist) peeled off from the substrate and dissolved in the cleaning liquid by causing ozone to flow through the cleaning liquid. Since the organic matter contains carbon and hydrogen, it is finally decomposed into carbon dioxide and water by ozone ventilation.

As described above, the above-described cleaning apparatus is suitable for miniaturization because it has high cleaning ability and high regeneration efficiency.
JP 2004-186208 A JP 2004-298552 A

  However, according to the conventional cleaning device, although depending on the quantitative regeneration capability of the regenerator, impurities after the regeneration and acids generated in the decomposition process are contained as impurities in the cleaning solution after the regeneration. When the concentration is high, there is a problem that an acid may corrode circuit patterns (particularly metals) on the substrate surface in the cleaning process with pure water in the next process.

  More specifically, the impurity is an intermediate organic substance in the process of decomposing the organic substance by ozone, and is an acid (for example, formic acid, glyoxylic acid, maleic acid, phthalic acid, muconic acid, oxalic acid, mesoxalic acid, etc.). 3A and FIG. 3B). In addition, the cleaning liquid remains thinly on the surface of the substrate transported to the next process. In this state, when the impurity concentration is high, rinsing the residual cleaning solution on the substrate with pure water causes the acid to corrode the circuit pattern.

  An object of the present invention is to provide a cleaning apparatus that prevents or reduces corrosion of a circuit pattern on a substrate surface in a cleaning process with pure water.

  In order to achieve the above object, the cleaning apparatus of the present invention includes at least two cleaning tanks for cleaning a substrate in stages, and a cleaning liquid after cleaning in a cleaning tank other than the final stage in a cleaning tank other than the final stage. The first circulation path to be circulated, ozone cleaning means to regenerate the cleaning liquid by ventilating the cleaning liquid after cleaning in the cleaning tank other than the final stage, and ozone ventilation means for refluxing the cleaning liquid to the cleaning tank other than the final stage; And a second circulation path for circulating the cleaning liquid after cleaning to the final stage in the final-stage cleaning tank.

  According to this configuration, the acid generated in the decomposition process by ozone may remain in the cleaning liquid in the cleaning tank other than the final stage, but the cleaning liquid in the final stage cleaning tank contains only a very small amount of acid. Corrosion of the circuit pattern on the substrate surface can be prevented in the process of cleaning with pure water in the process.

  Here, the cleaning liquid may contain either ethylene carbonate or propylene carbonate.

  Here, the ozone ventilation means may regenerate the cleaning liquid by ventilating ozone to the cleaning liquid after cleaning in the first cleaning tank, and return the recovered cleaning liquid to the cleaning tank immediately before the final stage. .

  Also, the cleaning method and the semiconductor manufacturing apparatus of the present invention include the same means as the above-described cleaning apparatus.

  As described above, according to the cleaning apparatus of the present invention, the circuit pattern on the substrate surface can be prevented from corroding during the cleaning process with pure water in the next step.

(Embodiment 1)
A cleaning apparatus according to an embodiment of the present invention is an apparatus for cleaning a substrate such as a glass substrate of a liquid crystal panel, a glass substrate of a PDP (plasma display panel), or a semiconductor wafer, and a semiconductor for manufacturing a liquid crystal panel, a PDP, or a semiconductor. It is installed as a process of manufacturing equipment. This cleaning apparatus has at least two cleaning tanks for cleaning the substrate in stages, uses ethylene carbonate as a cleaning liquid, and regenerates the cleaning liquid by ozone ventilation. In the cleaning tanks other than the last stage, there is an acid generated in the cleaning process due to ozone in the cleaning liquid due to ozone ventilation, but the cleaning liquid in the final stage is configured to contain only a very small amount of acid. This prevents corrosion of the circuit pattern on the substrate surface during the cleaning process with pure water.

  The cleaning liquid is ethylene carbonate (EC), propylene carbonate (PC), or a mixture thereof.

  Ethylene carbonate (melting point: 36.4 ° C., boiling point: 238 ° C., flash point: 160 ° C.) is a colorless and odorless solid at room temperature and needs to be heated to be used as a cleaning liquid, but can be used as an aprotic polar solvent. High boiling point, flash point, and low toxicity. As the cleaning liquid, first, the organic film has excellent peeling performance (fast peeling speed), and secondly, it is easy to decompose the resist dissolved in the liquid without reacting with ozone. And third, it has the property of being water-soluble (neutral).

  Propylene carbonate (melting point −48.8 ° C., boiling point 242 ° C., flash point 160 ° C. or higher) is almost the same in the first to third points. However, propylene carbonate has a demerit that it is slightly inferior in detergency at the first point and slightly affected by ozone at the second point as compared with ethylene carbonate. There is a merit that it can be easily used as a cleaning liquid without having to do so.

  FIG. 1 is a diagram illustrating a configuration of a cleaning device according to the first embodiment. In the figure, the cleaning apparatus 1 includes a carry-in tank 2, a cleaning tank 3, a cleaning tank 4, a relay tank 5, a cleaning tank 6, a tank 7, a tank 8, a tank 9, and a first regeneration unit (hereinafter referred to as an ozone ventilation unit). 10 and piping for circulating the cleaning liquid. There are roughly two circulation paths for the cleaning liquid by piping.

  One is a circulation path of the cleaning liquid through which ozone is passed, and is a first circulation path that circulates the cleaning liquid after cleaning in the cleaning tank other than the final stage to the cleaning tank other than the final stage. The circulation path cleaning liquid contains an acid. That is, the cleaning liquid used in the first-stage cleaning tank 3 is discharged to the ozone vent 10 through the discharge rod 17, the tank 7, the discharge rod 18, the pump 19, and the discharge rod 20. , The discharge tank 21, the supply pipe 223, the tank 8, the supply pipe 12, the pump 13, the filter F 2, the supply pipe 14, the floating flow meter 15, and the supply pipe 16 circulate to the cleaning tank 3.

  The other is a circulation path of the cleaning liquid in which ozone is not passed through the cleaning liquid, and a second circulation path that circulates the cleaning liquid after cleaning in the final-stage cleaning tank to the final stage. In other words, the cleaning liquid used in the final-stage cleaning tank 4 is circulated to the cleaning tank 4 via the tank 9, the supply pipe 24, the pump 25, the filter F 1, the supply pipe 26, the floating flowmeter 27, and the supply pipe 28. To do. In this way, the circulation path for the cleaning liquid that is ventilated with ozone is separated from the circulation path for the cleaning liquid that is not ventilated with ozone. The cleaning liquid that remains thinly on the substrate carried out from the cleaning tank 4 having the circulation path of the cleaning liquid that is not ventilated with ozone to the cleaning tank 6 contains a very small amount of acid generated in the resist decomposition process by ozone.

  The carry-in tank 2 is a carry-in port for the glass substrate of the liquid crystal panel, and has an air tube A. The air tube A is also called an air knife, and sprays compressed air in the direction of the cleaning tank 3 in order to prevent the cleaning liquid on the substrate from flowing backward from the cleaning tank 3 to the carry-in tank 2.

  The cleaning tank 3 has nozzle tubes B to G and air tubes H and I, and performs the first stage cleaning on the substrate transferred from the loading tank 2. The nozzle tubes B to G eject the cleaning liquid supplied from the tank 8 onto the surface of the glass substrate. Thereby, the glass substrate to which the resist is attached is cleaned in the first stage by the cleaning liquid ejected from the nozzle tubes B to G. The cleaning liquid at this time is a cleaning liquid regenerated by ozone ventilation, and is supplied from the tank 8. That is, the cleaning liquid in the tank 8 is supplied via the supply pipe 12, the pump 13, the filter F 2, the supply pipe 14, the floating flow meter 15, and the supply pipe 16 as a piping path for supplying the cleaning liquid from the tank 8 to the cleaning tank 3. It is supplied to the nozzle tubes B to G. The air tubes H and I are air knives, and drop the cleaning liquid on the glass substrate into the cleaning tank 3 by ejecting the compressed air supplied from the air compressor onto the glass substrate. The cleaning liquid that has flowed down from the glass substrate is supplied from the cleaning tank 3 to the ozone ventilation unit 10 through the discharge pipe 17, the tank 7, the discharge pipe 18, the pump 19, and the discharge pipe 20.

  The cleaning tank 4 has nozzle tubes J to O and air pipes P and Q, and performs a second-stage cleaning on the substrate transported from the cleaning tank 3 using a cleaning liquid that is not ventilated with ozone. The nozzle tubes J to O eject the cleaning liquid supplied from the tank 9 onto the surface of the glass substrate. Thereby, the glass substrate after washing | cleaning by the washing tank 3 is wash | cleaned with the washing | cleaning liquid ejected from nozzle tube JO. The cleaning liquid at this time is supplied from the tank 9. That is, the cleaning liquid in the tank 9 is supplied via the supply pipe 24, the pump 25, the filter F 1, the supply pipe 26, the floating flowmeter 27, and the supply pipe 28 as a piping path for supplying the cleaning liquid from the tank 9 to the cleaning tank 4. Supplied to nozzle tubes JO. The air tubes P and Q are the same as the air tubes H and I described above. The cleaning liquid flowing down from the glass substrate is discharged from the cleaning tank 4 to the tank 9 via the discharge pipe 30.

The relay tank 5 conveys the glass substrate carried out from the cleaning tank 4 to the cleaning tank 6.
The cleaning tank 6 includes nozzle tubes R to V and an air tube W, and cleans the glass substrate carried out from the relay tank 5 with pure water. Since the cleaning liquid that remains thinly on the glass substrate conveyed from the previous stage contains only a very small amount of acid, corrosion of the metal wiring on the surface of the glass substrate can be prevented.

  The tank 7 has a heater 7 a, temporarily stores the cleaning liquid discharged from the cleaning tank 3 through the discharge pipe 17, and discharges it to the ozone ventilation section 10 through the discharge pipe 18, the pump 19, and the discharge pipe 20. It is a buffer tank. The heater 7a warms the cleaning liquid. When the cleaning liquid is ethylene carbonate, the temperature is 40 ° C. to 200 ° C., and when the cleaning liquid is propylene carbonate, the temperature is within the range of room temperature to 200 ° C. This is because ethylene carbonate (melting point: 36.4 ° C.) is solid at room temperature and thus liquefies.

  The tank 8 includes a heater 8 a and a level sensor 8 b that measures the amount of liquid in the tank 8, and collects the cleaning liquid regenerated by the ozone ventilation unit 10 through the discharge rod 21 and the supply pipe 223. The heater 8a is the same as the heater 7a. When the liquid amount measured by the level sensor 8b is reduced from the set liquid amount L by a control unit (not shown), a new cleaning liquid is supplied from the new cleaning liquid supply pipe 34 to the tank 9, and when the set liquid amount H is reached, the supply is stopped. Is done.

  The tank 9 has a heater 9 a and collects the cleaning liquid used in the cleaning tank 4. This cleaning liquid circulates in the cleaning tank 4 through the supply pipe 24, the pump 25, the filter F 1, the supply pipe 26, the floating flowmeter 27, and the supply pipe 28. The heater 9a is the same as the heater 7a.

  The unidirectional connecting pipe 9b supplies the cleaning liquid from the tank 9 toward the tank 8 when the amount of the cleaning liquid in the tank 9 exceeds the specified amount.

  The first regeneration unit (ozone ventilation unit) 10 regenerates the cleaning liquid by ventilating ozone from the tank 7 through the discharge pipe 18, the pump 19, and the discharge pipe 20.

  Thus, the cleaning apparatus 1 performs two-stage cleaning in the cleaning tank 3 and the cleaning tank 4 in order to peel the organic film from the glass substrate to which an organic film such as a resist is adhered, and further thinly remains on the surface of the substrate. In order to flow the cleaning liquid to be cleaned, cleaning with pure water in the cleaning tank 6 is performed. The cleaning liquid in the cleaning tank 3 in the first stage is a cleaning liquid regenerated by aeration of ozone, and there is an acid generated in the decomposition process by ozone. On the other hand, since the cleaning liquid in the second-stage cleaning tank 4 is a cleaning liquid that is not ventilated with ozone, no acid is generated in the second stage, but it is carried from the first-stage cleaning tank 3 to the second-stage cleaning tank 4. There is acid brought in by the cleaning liquid remaining on the glass substrate. This acid is mixed into the second stage cleaning liquid, but the second stage cleaning liquid contains only a very small amount of acid. Therefore, since the cleaning solution that remains thinly on the glass substrate carried out from the second-stage cleaning tank 4 to the next-stage cleaning tank 6 that is rinsed with pure water contains only a very small amount of acid, Corrosion due to acid of metal wiring can be prevented.

  FIG. 2 is a block diagram illustrating a detailed configuration example of the ozone ventilation unit 10. The ozone ventilation unit 10 mainly performs resist decomposition by ozone gas ventilation and ozone deaeration by nitrogen gas ventilation. In the figure, the ozone ventilation unit 10 is configured so that the cleaning liquid passes through, and is stored in the raw liquid tank 100 that stores the cleaned cleaning liquid discharged from the tank 7 and taken in from the raw liquid intake pipe 101 as a raw liquid. A stock solution pump 102 that sucks the stock solution and sends it to the first aeration treatment tube 104 via the check valve 141, the valve 140, and the floating flowmeter 103, and a first aeration treatment tube that ventilates ozone gas to the stock solution supplied from the stock solution pump 102. 104, a second aeration treatment pipe 106 that ventilates ozone gas from the first aeration treatment pipe 104 via the connection pipe 105, and a cleaning liquid supplied from the second aeration treatment pipe 106 via the connection pipe 107. A degassing treatment tube 108 for degassing ozone gas by ventilating nitrogen gas through the degassing treatment tube 108 and a connecting tube 109. And a processing liquid tank 110 to accumulate the cleaning liquid supplied as a processing solution Te.

  The heater 142 and the cooling pipe 122 in the undiluted liquid tank 100 are for adjusting the temperature so that the undiluted liquid does not solidify and has a temperature suitable for regeneration.

  The cooling pipe 122 in the stock solution tank 100 cools the stock solution with cold water supplied from the outside via the cold water intake pipe 121 and drains it outside through the cold water discharge pipe 123.

  A cooler 119 attached around the first aeration treatment tube 104 cools the first aeration treatment tube 104 with cold water supplied from outside via a cold water intake tube 118, and externally passes through a cold water discharge tube 120. Drain into. Thereby, the solubility of ozone gas is increased, the decomposition of the ozone gas is prevented, and the temperature is maintained at an appropriate temperature that promotes the decomposition of the resist by the ventilation of the ozone gas.

  In addition, the flow rate of the stock solution pump 102 is adjusted according to the liquid level measured by the level sensor 144 by a control unit (not shown).

  The heater 132 warms the cleaning liquid after regeneration and deaeration to about 80 ° C., for example. The heater 132 is adjusted by the temperature measured by the thermometer 133.

  The laser sensor 130 measures the resist color concentration of the cleaning solution after ozone regeneration that bypasses the bypass pipe 129 and the bypass pipe 131 by the four-way valve 128. The cleaning solution is colorless and transparent when the resist is not dissolved, but becomes darker, orange and brown as the solubility of the resist increases. Since the cleaning liquid after regeneration is normally transparent, the resist color concentration measured by the laser sensor 130 is used for determining whether or not an abnormality has occurred in the ozone gas system, the cleaning liquid circulation system, or the like.

  The processing liquid in the processing liquid tank 110 is supplied to the tank 8 through the discharge basket 21 shown in FIG. 1 as a regenerated cleaning liquid.

  Regarding the configuration relating to the ozone gas in the ozone ventilation section 10, the ozone gas sent out by the ozone gas generator (not shown) is supplied from the ozone intake pipe 114 to the second ventilation treatment pipe 106, and the first ventilation treatment is performed via the ozone pipe 115. It is supplied to the pipe 104 and further ventilated into the stock solution tank 100 through the ozone pipe 116.

  Regarding the configuration related to the nitrogen gas in the ozone ventilation section 10, the nitrogen gas sent out by a nitrogen gas cylinder (not shown) is supplied to the degassing treatment pipe 108 via the nitrogen intake pipe 124, and the stock solution tank via the nitrogen pipe 125. 100 is discharged. Here, an inert gas called nitrogen gas is used, but air or other gas (gas) may be used.

  The ozone gas and nitrogen gas supplied to the stock solution tank 100 are exhausted from the exhaust pipe 117 via the ozone decomposer 145.

  The heater 126 preheats the cleaning liquid flowing through the degassing processing tube 108 prior to heating of the cleaning liquid in the processing liquid tank 110. This preheating also serves as decomposition of ozone gas in the degassing treatment tube 108 and promotion of degassing. At this time, the heating amount is adjusted according to the temperature measured by the thermometer 127 by a control unit (not shown).

The ozone sensors 135 and 137 measure the concentration of ozone gas, respectively.
The ozonolysis device 145 decomposes ozone gas with a catalyst to render it harmless.

  3A and 3B are explanatory views showing an example of a resist decomposition process by ozone ventilation. FIG. 3A shows a decomposition process of a general novolac resin as a main component of the resist. As shown in the figure, the novolak resin is decomposed into phenol and further decomposed into muconic acid and muconaldehyde. Muconic acid is degraded directly to glyoxylic acid or via maleic acid to glyoxylic acid. Also, muconaldehyde is decomposed directly into gliosar or via malealdehyde to gliosar. Glyoxylic acid and gliosal are broken down into formic acid and further broken down into carbon dioxide and water.

  FIG. 3B shows a decomposition process of naphthoquinonediaziso, which is a general photosensitizer (photocuring agent) contained in the resist. As shown in the figure, naphthoquinone diazio is decomposed into naphthalene, further decomposed into 2-ozonates, and further decomposed into phthalic acid via phthalaldehyde. Phthalic acid is broken down to gliosal, maleic acid, or mesoxalic acid. Gliosal is decomposed into formic acid, maleic acid is decomposed into formic acid via glyoxylic acid, and mesoxalic acid is decomposed into oxalic acid. Formic acid and oxalic acid are broken down into carbon dioxide and water.

  Although depending on the quantitative regeneration capability of the ozone ventilation part 10, impurities derived from the resist and acids generated in the decomposition process are contained as impurities in the cleaning liquid after the ozone ventilation.

  As described above, according to the cleaning apparatus of the present embodiment, the cleaning liquid in the cleaning tanks other than the final stage contains acid generated in the resist decomposition process by ozone, but the cleaning liquid in the final stage cleaning tank is very much. Since only a very small amount of acid is contained, the cleaning liquid remaining thinly on the substrate transported from the final stage also contains a very small amount of acid. Therefore, corrosion of the circuit pattern on the substrate surface can be prevented in the cleaning process with pure water in the next process.

  FIG. 4 is a diagram showing a configuration of a first modification of the cleaning device in the present embodiment. The cleaning device 160 shown in the figure is different from the cleaning device 1 shown in FIG. 1 in that one cleaning tank is added. As a result, the cleaning ability can be further increased while circulating and reusing the cleaning liquid. That is, the cleaning device 160 is mainly different in that a cleaning tank 161, a tank 162, and a unidirectional connecting pipe 162b are added, and a point that the discharge rod 21 is discharged to the tank 162 instead of the tank 8.

  In the cleaning device 160, the first circulation path circulates the cleaning liquid after cleaning in the cleaning tank other than the final stage to the cleaning tank other than the final stage. This circulation path includes the ozone ventilation part 10. The second circulation path is a circulation path for the cleaning liquid in which ozone is not passed through the cleaning liquid, and the cleaning liquid after cleaning is circulated to the final stage in the final-stage cleaning tank.

  In the first circulation path, the cleaning liquid regenerated by the ozone ventilation unit 10 is used in the second-stage cleaning tank 161, and the cleaning liquid in the cleaning tank 161 is used in the first-stage cleaning tank 3. Accordingly, the second stage becomes a cleaner cleaning liquid, and the cleaning efficiency can be improved.

  FIG. 5 is a diagram showing a configuration of a second modification of the cleaning device in the present embodiment. Compared with the cleaning apparatus 1 shown in FIG. 1, the cleaning apparatus 1 a of FIG. 1 includes a second regeneration unit (hereinafter referred to as a crystallization unit) 11, a valve 222, a supply pipe 31, a supply pipe 32, and a valve 33. Is different. Explanation of the same points is omitted, and different points will be mainly described below.

  The crystallization unit 11 obtains a part (for example, 10%) of the cleaning liquid supplied from the ozone ventilation unit 10 through the discharge pipe 21 from the valve 222, separates impurities by crystallization, and cleans the cleaning liquid with high purity. To play. Here, crystallization means that crystals are precipitated from the liquid phase, thereby separating specific components (impurities) from the liquid phase.

  The cleaning liquid regenerated by the ozone ventilation unit 10 is returned to the tank 8 through the discharge pipe 21 and the supply pipe 223. In addition, a part of the cleaning liquid containing impurities such as the resist from the ozone ventilation unit 10 and the acid in the resist decomposition process is supplied to the crystallization unit 11 through the valve 222 and the supply pipe 31. Impurities are separated and purified by crystallization and refluxed to the tank 9.

  FIG. 6 is a diagram illustrating a more detailed configuration example of the crystallization unit 11 illustrated in FIG. 5. In the figure, the crystallization unit 11 includes a drum flaker 11a, a belt conveyor 11b, a crystal purification device 11c, a tank 11d, a pump 11e, and a filter F3.

  The drum flaker 11a continuously cools and solidifies the cleaning liquid discharged from the supply pipe 31 and pulverizes it. As a result, ethylene carbonate powder (hereinafter referred to as powder) solidified into crude crystals is continuously produced. The melting point of ethylene carbonate is 36.4 ° C, and this cooling and solidification only makes the temperature lower than 36.4 ° C, so that it can be easily solidified at room temperature.

  The belt conveyor 11b conveys the powder generated by the drum flaker 11a and continuously supplies it to the crystal refiner 11c.

  The crystal refining device 11c separates impurities by crystallization of the powder and purifies it with high purity. In this crystallization, impurities are discharged from the crystal of ethylene carbonate by a so-called sweating phenomenon.

  The tank 11d has a heater and is liquefied by heating the powder from which impurities are removed and purified to a high purity with the heater.

  The pump 11 e supplies the regenerated cleaning liquid from the tank 11 d to the tank 9 through the filter F 3 and the supply pipe 32.

  FIG. 7 is a block diagram showing a detailed configuration example of the crystal purification device 11c. In the figure, the crystal purification apparatus 11c includes a cylindrical body 150, a feeder 151, a liquid separator 152, a receiving port 153, a transfer screw 154, a screw conveyor 155, a melting device 156, an outlet 157, a waste port 158, and a heater 159.

  The coarse crystal powder conveyed from the belt conveyor 11 b is continuously supplied as a raw material to the receiving port 153, and further transferred to the lower part in the cylindrical body 150 by the transfer screw 154 in the feeder 151. Powder is conveyed upward while being loosened by a screw conveyor 155 with special blades rotating at a low speed, and in the process, it is repeatedly compressed and released in conjunction with the movement of the blades, and purified by sweating in a solid-liquid equilibrium state. Is done. In other words, when the powder crystals are maintained at a temperature close to the melting point, the impurities contained therein are discharged by sweating. Furthermore, a part of the powder that has reached the top of the tower is melted by a melting device 156 installed at the upper portion, and becomes a reflux liquid and flows down in the cylindrical body 150. This reflux liquid raises the temperature of the crystal by coming into contact with the crystal and promotes the sweating phenomenon to discharge the impurities inside the crystal to the surface, and by washing the crystal surface of the powder by contacting with the crystal, the impurities are concentrated. However, it flows in the lower part of the cylindrical body 150. The liquid separator 152 in the lower part of the cylindrical body 150 discharges the liquid containing the concentrated impurities from the waste outlet 158. The heater 159 heats the cylindrical body 150 to a temperature close to the melting point but does not reach the melting point.

  As a result, most of the powder that has reached the top of the tower from the lower part of the cylindrical body 150 by the screw conveyor 155 is purified to an extremely high purity in the process of being conveyed and is carried out from the outlet 157. In addition, since a part of the reflux liquid is recrystallized before reaching the lower part of the column, it can be purified to a crystal having a very high yield and a purity of almost 100%.

  As described above, the crystal purification device 11c promotes the separation of impurities, the cleaning of the crystal surface, heat transfer, and mass transfer by stirring, and efficiently purifies with a short residence time. The crystal purification device 11c includes, for example, Kureha Crystal Purifier (KCP) manufactured by Kureha Techno Engineering Co., Ltd.

  Here, the impurity concentration in the cleaning liquid in the cleaning apparatus 160 shown in FIG. 4 will be considered. When operation starts with a completely new cleaning solution (contains no impurities), the resist dissolved in the cleaning solution along with the processing of the substrate increases the resist-induced impurities and the impurities (called intermediate products) generated in the decomposition process due to ozone ventilation. To do.

  In particular, if attention is paid to the intermediate product, the cleaning liquid containing the intermediate product having a certain concentration generated in the ozone ventilation section circulates in the tank 162, the cleaning tank 161, the tank 8, and the cleaning tank 3, and the concentration is the tank. 162 and tank 8 are almost equal. The increase in impurities in the tank 9 is due to impurities contained in the cleaning liquid adhering to the substrate entering the cleaning tank 4 from the cleaning tank 161, but the amount is clearly smaller than the increase in the tank 162. .

  The cleaning liquid of the circulation system of the tank 162 and the tank 8 is reduced by the amount adhering thinly to the substrate surface and taken out to the cleaning tank 4 and the amount drawn by the exhaust of each tank. A new cleaning liquid is added to the tank 9 for the decrease, and the tank 9 is added to the tank 162 for that amount. Further, since the impurity concentration in the added cleaning liquid is much smaller than the impurity concentration in the cleaning liquid to be taken out, the substrate is saturated at a certain concentration when the substrate processing is performed. Actually, the 1.2μ-thick resist on the 1m x 1.2m LCD substrate was stripped continuously, and the impurity concentration in the cleaning liquid of the tank 162 was less than 0.8% when the substrate processing was about 15,000. Saturated at a concentration of

  Next, the impurity concentration in the tank 9 will be considered. FIG. 8 assumes that the tank 162 and the tank 8 are in the saturated state as described above and have an impurity concentration of 1%, and the tank 9 stores the new cleaning liquid and the number of treatments in the tank 9 and the impurities of the cleaning liquid. It is a figure which shows the example of a change of a density | concentration. The number of processed sheets on the horizontal axis indicates the number of cleaned substrates. The impurity concentration suddenly increases until the number of treatments started with the new cleaning liquid is about 1,000, and gradually increases up to about 4,000. Thereafter, the impurity concentration is saturated. In this saturated state, it is considered that the amount of impurities (referred to as intermediate products) generated in the decomposition process by ozone ventilation is balanced with the amount by which the intermediate products are further completely decomposed by ozone ventilation. In this saturated state, the impurity concentration of the cleaning liquid in the tank 9 is about 0.27% with respect to the impurity concentration of 1% in the cleaning liquid in the tank 162. In other words, the circulation path that circulates between the final-stage cleaning tank 4 and the final-stage tank 9 is different from the circulation path that includes the ozone ventilation of the cleaning tanks 3, 162 other than the final-stage and the tanks 7, 8, 162 other than the final-stage. This means that the impurity concentration in the tank 9 is reduced to about 1/4 of the preceding tank impurity concentration. FIG. 9 is an explanatory diagram showing the entry and exit of impurities, which are the premise of the impurity concentration characteristics shown in FIG. The figure shows the amount of impurities entering and leaving the tank 9 shown in FIG. The cleaning tank 3, the cleaning tank 161, and the cleaning tank 4 are referred to as first to third cleaning tanks. Further, the impurity concentration of the tank 8 and the tank 162 is x%, and the impurity concentration of the tank 9 is y%. The amount of cleaning liquid taken out per substrate by exhaust in the three cleaning tanks is 50 cc, and the amount of cleaning liquid remaining thinly on the substrate between the cleaning tanks is 30 cc per board. Further, the amount of the cleaning liquid in the tank 9 is 80 liters. In this case, the replenishment amount of the new cleaning liquid to the tank 9 per substrate processing is 30 + 50 cc, and the cleaning liquid replenishment from the tank 9 to the preceding tank 162 is 30 + 50 * 2/3 cc. Then, the amount of impurities brought into the tank 9 is 30 * x%, and the amount of impurities brought out from the tank 9 is (30 + 50 * 2/3) * y%.

  The impurity concentration in the tank 9 increases after the cleaning with the new cleaning liquid is started. However, when the amount of impurities brought in is equal to the amount of impurities brought out, the state becomes an equilibrium state and becomes saturated. In this equilibrium state, 30 * x% = (30 + 50 * 2/3) * y%, and therefore y = 0.2727x. That is, the impurity concentration of the tank 9 is saturated while being about ¼ of the average impurity concentration of the two previous stages.

  In this way, the impurity concentration is saturated and does not deteriorate any further, so that it is not necessary to replace the cleaning liquid by simply replenishing the amount taken out.

  As described above, according to the cleaning apparatus in the present embodiment, the cleaning liquid that remains thinly on the substrate carried out from the final stage contains only a very small amount of acid generated in the decomposition process by ozone ventilation. Corrosion of the circuit pattern on the substrate surface can be prevented in the process of cleaning with pure water in the process.

  Note that the cleaning apparatus shown in FIG. 5 is not limited to two stages, and a three-stage cleaning tank may be provided.

  The present invention is suitable for a cleaning apparatus for removing or removing a resist in a process for manufacturing a liquid crystal panel or a semiconductor.

2 is a diagram illustrating a configuration of a cleaning device in Embodiment 1. FIG. It is a block diagram which shows the structure of a 1st reproduction | regeneration part (ozone ventilation part). It is explanatory drawing which shows the decomposition | disassembly process of a resist. It is explanatory drawing which shows the decomposition | disassembly process of a resist. It is a figure which shows the structure of the 1st modification of a washing | cleaning apparatus. It is a figure which shows the structure of the 2nd modification of a washing | cleaning apparatus. 3 is a diagram illustrating a more detailed configuration example of a second reproduction unit (crystallization unit) 11. FIG. It is a block diagram which shows the detailed structural example of a crystal refinement | purification apparatus. It is a figure which shows the example of a change of the process number of sheets in a washing | cleaning apparatus, and the impurity concentration of a washing | cleaning liquid. It is explanatory drawing which shows the entrance / exit of the impurity used as the premise of an impurity concentration characteristic. It is a figure which shows the structure of the washing | cleaning apparatus in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cleaning device 2 Carry-in tank 3 Cleaning tank 4 Cleaning tank 5 Relay tank 6 Cleaning tank 7, 8, 9 Tank 10 Ozone ventilation part 11 Crystallization part

Claims (5)

At least two washing tanks for washing the substrate in stages;
A first circulation path for circulating the cleaning liquid after cleaning in a cleaning tank other than the final stage to a cleaning tank other than the final stage;
An ozone ventilation means for regenerating the cleaning liquid by ventilating ozone into the cleaning liquid after cleaning in the cleaning tank other than the final stage, and refluxing to the cleaning tank other than the final stage;
A cleaning apparatus comprising: a second circulation path for circulating the cleaning liquid after cleaning in the final-stage cleaning tank to the final stage without aeration of ozone to the cleaning liquid. The cleaning apparatus according to claim 1, wherein the cleaning liquid contains either ethylene carbonate or propylene carbonate. 3. The ozone aeration unit regenerates the cleaning liquid by ventilating ozone to the cleaning liquid after cleaning in the first cleaning tank, and returns the cleaning liquid after regeneration to the cleaning tank immediately before the final stage. The cleaning device described. A cleaning method using at least two cleaning tanks for cleaning a substrate in stages,
Circulate the cleaning solution after cleaning in the cleaning tank other than the final stage to the cleaning tank other than the final stage.
Regenerate the cleaning liquid by aeration of ozone into the cleaning liquid after cleaning in the cleaning tank other than the final stage, and return to the cleaning tank other than the final stage,
A cleaning method characterized in that the cleaning liquid after cleaning is circulated to the final stage in the final-stage cleaning tank without passing ozone through the cleaning liquid. A semiconductor manufacturing apparatus comprising the cleaning apparatus according to claim 1.

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