KR20090025104A - Enhancement of the recovery efficiency in the waste photoresist stripper recycling process - Google Patents

Abstract

A method for enhancing recovery efficiency in the waste photoresist stripper recycling process is provided to collect the stripper solvent of high quality from the waste photoresist stripper and to improve recovery efficiency of the stripper solvent by minimizing the loss of thermal energy used in a recycling process and the recycled photoresist stripper. A method for enhancing recovery efficiency in the waste photoresist stripper recycling process comprises a step for controlling the concentration of the photoresist resin to become no greater than the maximum saturation concentration crystallizing the molten photo resist resin. The device for recycling the photoresist stripper comprises a waste photoresist stripper feeder, a distillation tower(15) connected to the feeder, a reboiler(6) connected to the floor(5) of the distillation tower, and a condenser(3) connected on the top of the distillation tower.

Description

Enhancement of the recovery efficiency in the waste photoresist stripper recycling process}

The present invention relates to a method for improving the reproducing yield in the process of regenerating the photoresist stripper, and more particularly, to improve the reproducing yield of the stripper solvent from the photoresist stripper waste liquid generated in the manufacturing process of the liquid crystal display device or semiconductor device. It is related to the method.

The stripper waste liquid generated during the manufacturing process of electronic components such as semiconductor wafers and liquid crystal display device glass substrates contains impurities such as moisture and heavy metals together with the photoresist resin in addition to the stripper solvent. Most of these stripper wastes are incinerated or low-level recycled as process fuels, which is undesirable because they cause secondary pollution and inefficient energy consumption, leading to environmental pollution and weakening corporate competitiveness in the IT industry. Moreover, due to the rapid development of IT technology, the 7th generation production line, which can manufacture not only commercially available 40 to 47 inch LCD panels but also 82 inch size products, is operating for LCD production with the largest amount of stripper waste liquid. As the development of the 9th generation production line development plan is being made, the size of LCD substrates is growing rapidly and the types of substrates are diversified. Accordingly, the quantity of stripper solvent is also increasing proportionally. In view of this reality, the recycling technology for stripper waste liquid, which can produce high quality recycled stripper solvent at a low cost by drastically reducing the cost by recovering the stripper solvent with high yield, goes beyond simple regeneration of stripper waste liquid. It is a desperate situation.

On the other hand, as a regeneration technology of the stripper waste liquid, regeneration methods by distillation using a filtration method and a distillation apparatus employing a nano filtration membrane separation device and an ion exchange treatment device have been developed in the past. As examples of the regeneration method using the filtration method, Japanese Patent Laid-Open Nos. 2005-215627 and 2003-167358 are representative. However, they have many problems in terms of regeneration throughput, loss, and running cost in common. In Japanese Patent Laid-Open No. 2005-215627, the regeneration yield is only 33%, and No. 2003-167358 shows no regeneration yield. In addition, as the prior art employing the distillation method, there may be exemplified by Korean Patent No. 0306649 and Japanese Patent Application Laid-Open No. 2005-288329, but even in this method, the recovery yield is not presented due to the large loss rate of the regeneration solvent. On the other hand, the prior arts are specified by the reprocessing method of the subprocess concept attached to the manufacturing process of electronic components such as semiconductor wafers or liquid crystal display glass substrates, and are not only limited to the stripper waste liquid of some specific composition but also mix the stripper composition. It only stays in simple total stripper recycling, which recovers in form and makes up for the lack of ingredients, and there is no consideration of the recovery yield (or “regeneration recovery rate”), so the recovery of the stripper waste liquid There is a problem with cost reduction and commercial implementation.

Accordingly, an object of the present invention is to recover the high-quality regeneration stripper solvent from the photoresist stripper waste liquid to increase the low regeneration yield, which is a problem of the conventional regeneration method, while the excessive amount of thermal energy generated during the regeneration process and the loss amount of the regeneration stripper. It is to provide a method and apparatus for easily enhancing or improving the regeneration yield of the stripper solvent by minimizing the amount.

In order to achieve the above object, the present invention is supplied with a first distillation apparatus for removing low-boiling impurities from the stripper waste liquid, stripper waste liquid from which the low-boiling impurities are removed from the primary distillation apparatus to remove the high-boiling impurities from the stripper composition and at the same time A secondary distillation apparatus for recovering the solvent in the form of a mixture, the high boiling point impurities are removed from the secondary distillation apparatus, and the stripper solvent composition is recovered, and each of the stripper solvent components is removed along with the fine moisture. A stripper waste liquid regeneration device composed of a tertiary distillation device regenerating with individual solvents; And adjusting the concentration of the dissolved photoresist resin contained in the column bottom of the distillation column of the secondary distillation unit, the reboiler or the distillation residue present in the connection pipe between the distillation column and the reboiler, the content of NMP as a stripper solvent, or both. Provide a way to improve recovery rates. However, the process for increasing the recovery rate is performed in a secondary distillation apparatus in which the photoresist stripper waste liquid is regenerated all at once while removing the high boiling point impurities. The primary distillation apparatus or the tertiary distillation apparatus may be arbitrarily deleted as necessary. have.

In the method for improving the photoresist stripper regeneration yield according to the present invention, the recovery rate increasing device includes a photoresist stripper waste liquid supply device, a distillation column connected to the supply device, a reboiler connected to the bottom of the distillation column tower, and a stripper waste liquid supplied to the reboiler. Analytical apparatus for measuring the concentration of dissolved photoresist resin and NMP content having the highest dissolving ability to the resin, a replenishment apparatus for detecting the analyzed content to supply stripper waste liquid and industrial grade NMP, and the top of the distillation column. It is preferred to include a condenser connected to the.

Therefore, the present invention can suppress the generation of adverse effects due to the solidified photoresist, which is a nonvolatile component for the regeneration process and the device through the regeneration method, as well as reducing unnecessary thermal energy, as well as low concentration from the general regeneration process It is characterized in that it provides a method and apparatus for easily promoting or improving the recovery yield of the stripper solvent by minimizing the loss of the stripper solvent discarded in large quantities with the photoresist resin.

Referring to the present invention in more detail as follows.

First, the photoresist stripper waste liquid according to the present invention will be described.

The method of increasing the reproducing yield of the present invention may be operated in a sub-step in addition to an etching process and a stripping process repeatedly performed in the manufacturing process of the semiconductor device or the liquid crystal display device, or after the manufacturing process of the semiconductor device or the liquid crystal display device. This can be done for the photoresist stripper waste liquids of various compositions that are discharged from the plant and collected. The photoresist stripper stock solution generally comprises individual stripper solvents such as an organic amine compound, a protic glycol ether compound and an aprotic polypolar compound, and the stripper waste solution generated after the stock solution is used in the stripping process is used to treat the stock solution. Together with the individual stripper solvents constituting it, a photoresist resin and water dissolved therein and a small amount of other organic solvents are included. The organic amine compound contained in the stripper stock solution or the stripper waste solution generally includes monoethanolamine (hereinafter referred to as "MEA") or monoisopropanolamine (hereinafter referred to as "MIPA"), and also a protic glycol ether compound. These generally include diethylene glycol monobutyl ether (hereinafter referred to as "BDG") or propylene glycol monomethyl ether acetate (hereinafter referred to as "PGMEA"), a thinner for cleaning substrates, and also aprotic polypolar compounds. Generally includes N-methyl pyrrolidone (hereinafter referred to as "NMP") or dimethylsulfoxide (hereinafter referred to as "DMSO"). It is common to include 1 to 30 parts by weight of the organic amine compound, 30 to 70 parts by weight of the protic glycol ether compound and 10 to 50 parts by weight of the aprotic multipolar compound based on 100 parts by weight of the stripper stock solution or the stripper waste solution. . In particular, as the aprotic polypolar compound, N-methyl pyrrolidone (hereinafter, referred to as “NMP”) is mostly used as a stripper solvent having a solubility parameter of 10 or more and the highest solubility in photoresist. . NMP, a stripper solvent, has excellent solubility but is expensive and is used in a limited manner in stripper compositions. Therefore, the stripper waste liquid to which the method for improving regeneration yield of the present invention is applied is generally 0 to 50% by weight, preferably 0.001 to 40% by weight, more preferably 5 to 35% by weight, most preferably 10 to 30% by weight. Stripper waste liquid containing NMP.

In the present invention, the "low boiling point impurity" is an impurity having a lower boiling point than the individual stripper solvent contained in the photoresist stripper waste liquid, and preferably has a boiling point of 130 to 30 ° C, more preferably 120 to 50 ° C, most preferably Is an impurity of 110 to 70 ° C., and is usually a small amount of an organic solvent such as water for washing or IPA for waste.

In the present invention, "high boiling point impurity" is an impurity having a higher boiling point than the individual stripper solvent contained in the photoresist stripper waste liquid, and preferably an impurity having a boiling point of 235 DEG C or higher, typically forming a resist pattern in a gate process. It is a photoresist resin stripped after being used for, and contains a small amount of other impurities such as nonionic surfactants.

The term “high purity electronic stripper solvent” in the present invention refers to a new liquid solvent used for preparing a photoresist stripper stock solution having a purity of 99.5% or more of individual stripper solvents, 0.1% or less of water content, or a ppb level of heavy metal or total metal. The lower limit of the moisture content does not need to be specifically set, but is generally about 0.001%, and the total metal content is preferably 500 ppb or less and the lower limit is not particularly limited, but it is 1 ppb. It is enough.

“Industrial grade solvent” in the present invention is a solvent having a higher content of impurities such as heavy metals than the standard of electronic grade solvent, and having a lower purification level than the electronic grade solvent. Generally, the purity is 98.0% or more and the water content is 0.5% or less. , Heavy metal or total metal content of 1000 ppb or more, but depending on the application may be of lower purity or higher impurity content.

In the present invention, the "integrated collection system" or "integrated regeneration method" refers to a separate waste liquid storage tank by collecting and collecting photoresist stripper waste liquids of various components and compositions discharged from a plurality of semiconductor wafers or TFT LCD manufacturing plants. After the transfer, they are mixed with each other. The type of stripper waste liquid to supply these types of stripper waste liquid as a raw material of the regeneration treatment process is called an integrated collection system, and the individual stripper solvents recycled from these stripper waste liquids or prepared by mixing them are prepared. The regeneration process and the regeneration method of the stripper waste liquid are characterized in that the photoresist stripper can be applied to all stripping processes in the manufacturing plant where the stripper waste liquid is discharged again.

The photoresist stripper regeneration apparatus of the present invention is a primary distillation apparatus for removing low-boiling impurities, a secondary distillation apparatus for removing high-boiling impurities and at the same time recovering the stripper composition solvent in the form of a mixture, and an electronic grade individual stripper with fine water removal. And a third distillation apparatus for regenerating the solvent, more specifically, the composition mixture of the composition having a narrow boiling point, which is difficult to separate from each other in high purity, to the electronic stripper individual solvent. However, the process for increasing the regeneration yield is added to the secondary distillation apparatus for removing the high boiling point impurities, the primary or tertiary distillation apparatus may be added or deleted as necessary.

First, the primary distillation apparatus is a multi-stage distillation column or a packed distillation column to remove low-boiling impurities such as water from the photoresist stripper waste liquid or stripper waste liquid pretreated by a method such as neutralization, precipitation, and filtration.

In addition, the secondary distillation apparatus is a multi-stage distillation column or a packed distillation column to remove the high-boiling impurities such as photoresist resin from the stripper waste liquid from which the low-boiling impurities are removed through the primary distillation unit and to recover the stripper solvent composition in the form of a mixture. The process (total stripper recycling) is carried out.

In the third distillation apparatus, as a spiral spinning band distillation column, a high boiling point impurity is removed through the secondary distillation apparatus and additionally removes fine moisture from the stripper solvent composition to form a stripper solvent composition. Depending on the boiling point of each of the strippers, separate stripper recycling is performed in sequence with individual stripper regeneration solvents of high purity electronic level. The spinning band distillation column is a very fast and effective gas-liquid by maximizing the contact surface area between the volatilized vapor component and the condensed liquid component by rotating the spiral stirring column device made of metal or teflon material at a high speed inside the tower. Equilibrium is designed to achieve high resolution purification efficiency. By varying the rotational speed of the spiral stirring column apparatus in the spinning band distillation column can be properly adjusted the separation efficiency of the distillation column, the rotational speed of the stirring column apparatus is preferably 1500 ~ 2500rpm. Therefore, by separating and refining each stripper solvent having a narrow boiling point from the spinning band type distillation column having excellent separation performance, it is possible to separate and regenerate separately with an electronic level quality having high purity.

The photoresist stripper regeneration process may be added to the stripping process, or the photoresist stripper waste liquid of various compositions may be collected and mixed in a separate waste liquid storage tank, and then pretreated as needed before the photoresist stripper regeneration process through distillation. In the pretreatment process, solids, insoluble modified photoresist components, organic acid components, and the like contained in the stripper waste liquid are removed by at least one of neutralization, precipitation, and filtration steps. The neutralization step in the pretreatment process is to remove the denatured organic acid components contained in the stripper waste liquid by mixing from the etching process or the developing process in the semiconductor wafer or TFT-LCD manufacturing process. In the case of 6, corrosion of the transfer line and the distillation equipment of the regeneration process may be caused, resulting in lowering of separation efficiency and instability of the regeneration process. Therefore, it is preferable to maintain the pH of the stripper waste liquid in the range of 6.5 to 8.5. For this purpose, for example, the neutralization step is performed by treating 20 wt% sodium hydroxide aqueous solution to 1.5 wt% to 3.2 wt% based on the pH of the waste liquid. By neutralizing the organic acids, the pH of the stripper waste liquid can be controlled within the appropriate range. Subsequently, the precipitation and filtration steps in the pretreatment process include suspended solids and insoluble components (mainly composed of decomposed residues of the polymers constituting the photoresist and heavy metal components generated during the etching of the conductive metal film), including neutralization. For a time sufficient to induce precipitation in the storage tank of the stripper waste liquid, for example, 1 to 12 hours, preferably 2 to 5 hours, and then primary filtration through a 20-100 μm scale sieve. Secondary filtration through a sieve of 0.1 ~ 10 ㎛ scale to separate the precipitate and stripper waste liquid. The filtration step may be performed by, for example, primary filtration with a 325 mesh (about 44 μm) sieve and then secondary filtration as a filter medium having a pore size of 1 μm.

First, when the photoresist stripper regeneration process is examined as a whole, in the case of the pretreated stripper waste liquid or stripper waste liquid which does not require pretreatment, the collected stripper waste liquid is transferred to an integrated regeneration treatment process in which a continuous distillation process is carried out, so that the water contained in the stripper waste liquid And impurities, such as dissolved photoresist, are sequentially removed and finally regenerated and recovered with an electronic grade stripper solvent. Each of the recovered high purity electronic grade stripper solvents may be used in the manufacture of stripper solvent compositions of all stripping processes of a plurality of semiconductor wafers or TFT-LCD manufacturing plants where stripper waste liquid has been discharged. Specifically, in the integrated regeneration process according to the present invention, low boiling point impurities such as water are removed from the first distillation apparatus, and high boiling point impurities such as dissolved photoresist components are removed from the secondary distillation apparatus, and the high boiling point impurities are removed. In the secondary distillation apparatus, the first strip is recycled by “total stripper recycling” in the form of a mixture of the entire stripper solvent composition. Subsequently, the recovered stripper solvent composition is sent to a spinning band type distillation apparatus, and then, firstly, a small amount of moisture remaining in the stripper solvent composition is secondarily removed due to the highly hygroscopic aprotic polypolar compound. The stripper solvent composition, which is composed of a mixture of various compositions and has a narrow boiling point region, is a very effective and fast method for producing a spiral stirring column device in a tower by rotating at a high speed while being heated above the boiling point of each component, that is, each individual stripper solvent. High-purity separation is possible due to high resolution due to repeated gas-liquid equilibrium, so that each stripper solvent is separated and distilled in sequential and high purity according to boiling point, and secondary regeneration by separate stripper solvent recycling is performed. Above stripe Each solvent contained in the fur composition is recovered as a high purity electronic stripper solvent.

Next, a process of improving the reproducing yield of the present invention will be described.

In order to maximize and improve the recovery rate of stripper regeneration in the process of distilling and regenerating the stripper waste liquid, a very fast and effective gas-liquid equilibrium formed between the vaporized vapor component and the condensed liquid component based on the material balance between the distillation column and the regeneration process is There is a continuing need for smooth operation of the regeneration process to ensure optimal maintenance. However, in the regeneration process such as the stripper waste solution in which the photoresist resin is dissolved, the dissolved photoresist resin, which is a non-volatile component, is precipitated during the distillation or in the latter part of the distillation, and is solidified in the regeneration apparatus. Excessive process operation, such as supplying excessive thermal energy to offset or excessively increasing or decreasing the supply of stripper waste to be regenerated, may result in high back pressure in the tower and may cause flooding. Can be. Meanwhile, in the operation of the conventional general regeneration process, the level of the stripper waste liquid supplied into the reboiler connected to the regeneration distillation column of the stripper waste liquid is more than the required level in order to suppress the occurrence of adverse effects on the regeneration process and the apparatus due to the solidified photoresist. When the photoresist resin, which is not sufficiently concentrated by being excessively extended, is transferred to the impurity collection tank for disposal, a large amount of stripper solvent contained in the waste liquid is also transferred and discarded, thereby increasing the yield of the stripper solvent. It's hard to expect.

Therefore, in the present invention, in order to solve the above problems, the photoresist stripper waste liquid is distilled by the secondary distillation apparatus to regenerate the stripper solvent composition into a mixture, and the dissolution photo from the stripper waste liquid supplied into the reboiler connected to the distillation column. The regeneration process is performed while determining the minimum level of the stripper waste liquid so that the resist resin is sufficiently concentrated but not solidified and precipitated, i.e., below the maximum saturation concentration of the dissolved photoresist resin. By performing the operation efficiently, the present invention provides a regeneration method for the stripper waste liquid which can reach a regeneration recovery rate greatly improved compared to the regeneration recovery rate obtained from a conventional general regeneration process.

In the process of distilling a photoresist stripper waste liquid and regenerating the stripper solvent composition in a mixture at a time, the concentration of the dissolved photoresist resin concentrated in the distillation residue supplied to the reboiler connected to the distillation column, or the concentration of such resin By analyzing the content of NMP that best dissolves the resin, the concentration of the dissolved photoresist resin proceeds to precipitate the resin in a solidified form, i.e., stripper waste liquid in a reboiler at a saturated photoresist resin concentration (distillation residue). ) Is determined as the first lowest level, and the recovery recovery rate is enhanced by supplying the stripper waste liquid to maintain the first lowest level. In addition, when the NMP concentration of the stripper waste liquid to be recycled separately is low, the recovery recovery rate may be further increased by additionally supplying NMP to the reboiler. The additional amount of NMP is a reference photoresist stripper wastewater containing a specific concentration of N-methyl pyrrolidone to obtain a desired recovery rate at the lowest of the objectives at the determined first lowest level (e.g. Example Stripper waste liquor with an NMP content of 30% by weight as in 1 and photoresist stripper waste liquor used for regeneration comprising any concentration of N-methyl pyrrolidone lower than the specific concentration (e.g., NMP as in Example 2). The stripper waste liquid having a content of 20% by weight) was analyzed for the N-methyl pyrrolidone content contained in the distillation residue at the first lowest level, respectively, to compare the weight ratio of the photoresist to the N-methyl pyrrolidone content. N-methyl pyrroly through a reboiler so that the reference photoresist stripper waste liquid and the photoresist stripper waste liquid used for regeneration become equal weight ratios. Is further supplied, the reboiling level when the N-methyl pyrrolidone is added is determined as the second lowest level, and then the standard is supplied by supplying N-methyl pyrrolidone to maintain the second minimum level or more. The recovery recovery rate can be enhanced to be close to the recovery recovery rate of the photoresist stripper waste liquid.

Regeneration recovery rate of the stripper solvent as well as improving the inefficiency of the regeneration process by minimizing the loss of thermal energy and regeneration stripper consumed during the regeneration process due to the non-volatile solidified photoresist resin through the method of improving the regeneration rate of the present invention Can be easily improved to ensure economic efficiency in terms of resource recycling.

In the regeneration recovery method according to the present invention, the first lowest water level is determined by detecting the concentration of the photoresist resin by an ultraviolet absorbance meter, and for this purpose, absorption of the dissolved photoresist resin in the stripper waste liquid (or distillation residue) is determined. The correlation table between the concentration of the dissolved photoresist resin and the absorbance should be prepared in advance using the characteristics. Subsequently, the concentration of the dissolved photoresist resin in the bottom of the distillation column or the distillation residue present in the connection pipe between the distillation column and the reboiler proceeds, so that the resin component solidifies and precipitates. Based on the concentration of the resist resin, that is, the maximum saturation concentration, at that point, the level of the stripper waste liquid in the reboiler is determined as the first minimum level, and the regeneration process for the waste liquid is efficiently maintained while maintaining the level of the reboiler above that standard. The recovery rate can be easily increased by appropriately adjusting the supply flow rate of the stripper waste liquid through the feeder from the stripper waste liquid storage tank for controlling. Such a method is particularly suitable for the treatment of stripper waste liquors comprising 0 to 40% by weight, preferably 5 to 35% by weight, more preferably 10 to 30% by weight of NMP.

In another method of enhancing the recovery rate according to the invention, it is necessary to analyze the N-methyl pyrrolidone content by gas chromatography for the second lowest water level determination. First, the level of NMP is compared to the total stripper solvent composition contained in the distillation residue at the first lowest level determined by the ultraviolet absorbance meter detection (e.g., a stripper waste liquid having an NMP content of 30% by weight). Re-boiling in the regeneration process for the type, if the level of NMP at the first trough level) is less than, the industrial grade NMP is added from a separate NMP supply tank connected to the reboiler to further lower the trough level When it is controlled to be suitable for the NMP content by supplying and replenishing, the concentration of the dissolved photoresist further proceeds from this time, and the distillation residue in the reboiler at that time based on the dissolved photoresist resin concentration measured when the resin precipitates. Determine the water level as the second lowest level and keep the level of reboiling above that standard. As is the NMP content in the waste liquid in the stripper reboiler it could easily increase the recovery rate of reproduction by controlled constant to the reference amount to efficiently control the playback process for the waste. Regeneration yield improvement method such as the embodiment is more preferably 0 to 25% by weight, even more preferably 0.001 to 20% by weight when the NMP content of the stripper waste liquid, preferably NMP concentration is less than 30% by weight And most preferably 0.001 to 10% by weight of the stripper waste liquid. The additionally supplied N-methyl pyrrolidone may also be used in electronic grade, but it is economical to use industrial grade N-methyl pyrrolidone, since the use of industrial grade hardly affects the recovery rate.

FIG. 1 is a schematic diagram showing an embodiment of a reproducing yield enhancing process of the present invention used for reproducing a photoresist stripper according to the present invention. First, the entire photoresist stripper regenerating process will be described with reference to FIG. 1.

Collecting stripper waste liquid discharged from LCD and semiconductor device manufacturing plants, and supplying tank for storing stripper waste liquid of various composition through pretreatment process such as neutralization, deposition and filtration through the use of separate storage tank, neutralizer and filtration device In T-1, the first feed pump 1-1 is operated to transfer the waste liquid to the primary distillation apparatus (or the first distillation apparatus). The stripper waste liquid transferred to the first distillation apparatus is heated to remove low boiling point substances such as low boiling point water and IPA. The stripper waste liquid from which low boiling point substances, such as water, were removed is operated by the 2nd conveying pump 1-2 and is sent to a 2nd distillation apparatus (or 2nd distillation apparatus). The conveyed waste liquid is rapidly heated to a temperature higher than the boiling point of the highest boiling component among the solvent components constituting the stripper, distills and extracts the entire stripper solvent composition all at once at the top of the distillation column, and condenses in the condenser (3) to temporarily store the tank (4). ). In addition, the dissolved photoresist resin concentrated in the column bottom 5 and the reboiler 6 so as not to be solidified and precipitated is operated by a third transfer pump 2-3 to a separate collection tank T-2. Dispose of after transfer. Subsequently, the stripper solvent composition recovered at once is transferred to the third distillation apparatus (or third distillation apparatus) by operating the fourth transfer pump 2-1 and the fifth transfer pump 2-2, and then the transferred stripper solvent. The compositions are sequentially heated above the boiling point of each of the individual stripper solvents, distilling and extracting the individual solvents sequentially in the upper part of the distillation column, and passing through the condenser and the temporary storage tanks (T-3, T-). 4, T-5) in order to recover.

Next, a method of improving the photoresist stripper regeneration yield according to the present invention will be described. Regeneration yield improving method of the present invention is characterized in that the step of recovering the entire stripper solvent composition at once in the second distillation apparatus of FIG. Therefore, in order to apply the method for improving the regeneration yield of the present invention, it must be a regeneration process that essentially includes recovering the entire stripper solvent composition at once, using a low boiling point impurity removal step or a third distillation using the first distillation apparatus illustrated in FIG. It is not necessary to include the individual stripper solvent regeneration step while removing the fine moisture using the apparatus.

First, if necessary, the photoresist stripper waste liquid is subjected to a pretreatment process and a process of removing water and low boiling point material through the first distillation apparatus, or the entire stripper solvent composition is recovered from the stripper waste liquid which omits such a process. In order to remove the same high boiling point impurities, the stripper waste liquid is operated to the distillation column 15 of the second distillation apparatus by operating the second transfer pump 1-2. At this time, it is necessary to prevent the physicochemical characteristics such as decomposition or deformation of the stripper solvent component from changing at high temperature, and for this purpose, it is preferable to perform a decompression operation by lowering the pressure in the tower with a decompression pump 14 connected to the distillation column. . Subsequently, the stripper waste liquid transferred to the second distillation apparatus is rapidly heated to a temperature above the boiling point of the solvent component having the highest boiling point in the stripper solvent composition to distill the stripper solvent composition in the form of a mixture to the top of the distillation column and condensed in the condenser (3). Recover to the temporary storage tank (4). In addition, the distillation residue containing the dissolved photoresist resin, which is concentrated in the column bottom 5 and the reboiler 6 and remains in a state of being solidified and not precipitated, is operated separately by operating the third transfer pump 2-3. Dispose of after transferring to T-2. However, as the amount of stripper solvents volatilized, distilled, and extracted according to the temperature rise in the distillation column increases, the dissolved photoresist resin, which is a nonvolatile component, during the distillation or in the latter part of the distillation, is precipitated in the tower bottom 5 and the reboiler 6. The solidification of the regeneration device causes the reduction of regeneration efficiency, which breaks the gas-liquid equilibrium of the distillation process line based on the material balance, and at the same time, excessive thermal energy consumption required for maintaining and raising the temperature in the tower is offset. Distillation process is operated inefficiently, such as distillation recovery rate is falling. Meanwhile, in the operation of the conventional general regeneration process, the general water level of the reboiler 6 connected to the regeneration distillation tower 15 of the stripper waste liquid is 30 to 50 cm high at the upper part of the heat line tube 6a of the reboiler (for example, High back pressure in the tower by excessively increasing it beyond the level of the reboiler in order to suppress the occurrence of adverse effects on the regeneration process and apparatus due to the solidified photoresist in the general operation, which is maintained at a level of 50% of the boiling height) (back pressure) is generated and the phenomenon of overflowing (flooding), as well as the efficiency of separation due to the increase in the amount of distillation in the column is reduced, unnecessary energy consumption due to the increase in the amount of reflux through the reflux tank (4) And distillation efficiency may eventually lead to a decrease in the recovery rate of the stripper waste liquor or insufficient concentration in the waste liquor in the reboiler. When the photoresist resin is transferred to an impurity collection tank for disposal, a large amount of stripper solvent contained in the waste liquid is also transferred and discarded, so it is difficult to expect a high yield recovery process due to an increase in loss of the stripper solvent.

Therefore, the present invention provides a recovery recovery rate improving device connected to the reboiler (3) and an enhancement method using the same to solve this problem.

Subsequently, with reference to FIG. 1, the method for improving the yield of the stripper waste liquid according to the present invention employing the recovery rate increasing apparatuses 7 to 13 will be described.

Referring to FIG. 1, a reboiler connected to the distillation column 15 while distillation is performed by a second distillation apparatus and the stripper composition solvent is recovered to the temporary storage tank 4 through the condenser 3 in the form of a mixture ( 6) The concentration of the dissolved photoresist in the stripper waste liquid fed into is gradually concentrated and increased. Subsequently, a portion of the stripper waste liquid containing the dissolved photoresist having increased concentration is introduced into the gas chromatography (7) to analyze the NMP content in the waste liquid, and at the same time, another portion of the waste liquid is transferred to an ultraviolet absorbance meter (8). The concentration of the dissolved photoresist in the waste liquid is detected by flowing in and measuring the absorbance of the stripper waste liquid. At this time, in order to detect the concentration of the dissolved photoresist by the ultraviolet absorbance photometer 8, a correlation table between the concentration and the absorbance of the dissolved photoresist is prepared in advance by using the absorption characteristics of the dissolved photoresist in the stripper waste solution. Should be used.

Subsequently, the concentration of the dissolved photoresist resin in the stripper waste liquid in the reboiler is increased and the dissolved photoresist concentration detected by the ultraviolet absorbance spectrometer 8 is dissolved at the time when the concentration of the dissolved photoresist resin starts to precipitate as a solidifying component. It may be referred to as the maximum saturation concentration of the resist, and at this point, the level of the stripper waste liquid in the reboiler may be determined as the first lowest level. Therefore, when the dissolved photoresist concentration detected by the ultraviolet absorbance photometer 8 does not exceed the maximum saturation concentration, the first controller 8a issues an output signal to open the first flow control valve 9 and 6 By operating the transfer pump (2-4) to circulate the upper part of the reboiler is a certain flow is made inside the reboiler can be delayed as much as possible the point of precipitation of the dissolved photoresist.

On the contrary, the dissolved photoresist concentration detected by the ultraviolet absorbance spectrometer 8 reaches the maximum saturation concentration, thereby increasing the flow rate of the stripper waste liquid supplied into the reboiler 6 to maximize the concentration of the dissolved photoresist. In the case where it is necessary to reduce the pressure, the first controller 8a issues an output signal to open the second flow control valve 10 and operate the third transfer pump 2-3 to discharge the waste liquid having the maximum concentration of the dissolved photoresist. The part is transferred to a separate collection tank T-2, and at the same time, the first controller 8a generates another output signal to operate the second transfer pump 1-2 to supply the stripper waste liquid supplied into the reboiler. By increasing the flow rate, the level of the stripper waste liquid in the reboiler can be maintained above the first minimum level.

Referring to the results of the recovery recovery in Examples 1 to 3 and Table 3 for the method for improving the recovery rate, the level of the reboiler according to the embodiment of the present invention for the stripper waste liquid having the NMP content of 10 to 30% by weight is conventional. If the conventional water level is maintained at a level of 25.3% to 12.9% relative to the 50% level of reboiling height, or the maximum saturation concentration of the dissolved photoresist resin is maintained at a level of 9.0% to 25.0% by weight. The recovery rate of waste stripper was 72% to 85%. In addition, in the regeneration process for stripper waste liquid containing 30% by weight of NMP, it was possible to obtain the highest high recovery rate with the lowest first level of reboiler.

On the other hand, with reference to the results of the recovery recovery rate of Figure 1 and Table 3 and Table 4 will be described another method of the recovery recovery rate according to the present invention.

First, by maintaining the level of the stripper waste liquid in the reboiler 6 above the first minimum level to suppress the formation of solidified components due to the concentration and precipitation of the dissolved photoresist resin to improve the primary recovery rate. Subsequently, a portion of the stripper waste liquid is introduced into gas chromatography (7) to analyze the content of NMP relative to the total stripper solvent composition contained in the waste liquid. In addition, the second controller (7a) is based on the NMP content analyzed from the gas chromatography (7) content of NMP at the first lowest level of reboiling in the regeneration process for the stripper waste liquid type having an NMP content of 30% by weight. In the case of containing less than the level (10.9% of NMP content referring to Table 2), after calculating the deficiency of the NMP component in order to lower the minimum level of the waste liquid, an output signal is issued to generate the third flow control valve 13. Open and operate the seventh transfer pump (2-5) to transfer from the industrial grade NMP supply tank 11 to the reboiler to replenish. When it is detected that the industrial-grade NMP is supplied from the first load cell 12 by the shortage, the second controller 7a issues an output signal to close the third flow control valve 13 and to transfer the seventh transfer pump 2-5. Interrupt the supply and replenishment of industrial grade NMP.

Subsequently, by supplying and supplementing the industrial grade NMP to the reboiler 6 to control the NMP content, the concentration of the dissolved photoresist resin in the stripper waste liquid is further increased and precipitation starts to solidify. The dissolved photoresist concentration detected by the ultraviolet absorbance spectrometer 8 can be referred to as the maximum saturation concentration of the dissolved photoresist in the stripper waste liquid supplemented with the industrial grade NMP, and at this point, the stripper in the reboiler The level of the waste liquid can be determined as the second lowest level.

Subsequently, the level of the stripper waste liquid in the reboiler can be maintained above the second minimum level by controlling in the same manner as the method for improving the primary recovery recovery rate, and thereby the solidification component due to concentration and precipitation of the dissolved photoresist resin can be maintained. Further suppression of production can enhance the secondary recovery rate.

Referring to Examples 1 to 3 and the recovery recovery results of Tables 3 and 4 for the secondary recovery rate improvement method, another enhancement method of the present invention for the stripper waste liquid of the above type having an NMP content of 10% by weight Was further increased to 72% as a result of the addition of (replenishing industrial grade NMP with a concentration ratio of NMP and photoresist at a level of 2.3 at the first lowest level of reboiling in the regeneration process for stripper waste liquids with an NMP content of 30% by weight). It was found that the recovery rate was further increased to 81%, and the recovery rate was increased to 83%, which was increased to 79% for the stripper waste liquid having an NMP content of 20% by weight. In addition, it was confirmed that the recovery rate of 65% was improved to 79% as a result of the present invention for the four types of stripper waste liquids in the above-described implementation without NMP.

As described above, in the method for regenerating the photoresist stripper waste liquid, the method for improving regeneration yield according to the present invention reduces unnecessary thermal energy consumption and regenerates by improving an inefficient regeneration process due to a solid photoresist that is a nonvolatile component. By minimizing the loss of the stripper, it is possible to realize economic efficiency in terms of resource recycling, thereby realizing cost reduction. At the same time, the recycling process technology of the stripper waste liquid through the regeneration recovery method according to the present invention recovers and recycles the expensive stripper solvent from the photoresist stripper waste liquid, thereby contributing to the cost savings of the IT industry and greatly improving the environmental effect. It is a key environmental technology that will be highlighted in the future.

Hereinafter, the present invention will be described in detail with reference to Examples, but the scope of the present invention is not limited by Examples.

In the first regeneration process of the photoresist stripper waste liquids of various compositions generated in the semiconductor manufacturing process, the regeneration yield enhancement method of the present invention was applied, and the composition of the stripper waste liquids used is shown in Table 1.

 Photoresist stripper waste composition (% by weight) Photoresist resin NMP BDG MEA moisture IPA Etc Example One 2.8 30 55 0 10 1.9 0.3 2 2.4 20 60 8.1 8.2 1.2 0.1 3 1.9 10 62 15 9.3 1.5 0.3 4 2.0 0 78 10.3 7.9 1.5 0.3

 Table 2 shows the distillation conditions of the primary and secondary regeneration processes made through the secondary distillation apparatus and the tertiary distillation apparatus while performing the regeneration yield improving method according to the present invention from the stripper waste liquids of Examples 1 to 4. Indicated.

Example 1 Example 2 Example 3 Example 4 Primary regeneration process distillation conditions Vacuum Pressure (torr) 97 Distillation Temp. (℃) 132.7-158.0 103.1 ～ 157.8 Reflux Ratio 2 Secondary regeneration process distillation condition Vacuum Pressure (torr) 97 Distillation Temp. (℃) MEA - 98 ～ 111 102 to 107 NMP 125 to 142 125 to 140 - Reflux Ratio 10 10 7 Rotation Speed of Column (rpm) 1,700 ～ 1,800 1,800 ～ 1,900 1,700 ～ 1,800

Table 3 shows the results of the primary recovery recovery in accordance with the present invention from the stripper waste solution of Examples 1 to 4.

First low water level ratio (% of normal water level) NMP content (wt,%) compared to the entire stripper composition in the first lowest level concentrated waste liquid Photoresist content (wt,%) in the 1st minimum level concentrated waste liquid Concentration ratio in the concentrated waste solution based on the first lowest level (photoresist / NMP) Recovery rate (%) Example One 12.9 10.9 25.0 2.3 85 2 18.6 7.8 14.8 1.9 79 3 25.3 5.2 9.0 1.7 72 4 37.1 0 7.3 - 65

Table 4 shows the results of further improving the recovery rate by supplementing NMP in Examples 1 to 4 of Table 3.

Industrial grade NMP replacement Concentration ratio in the concentrated waste liquid based on the 2nd lowest water level (photoresist / NMP) Final recovery rate Example 2 supplement 2.3 83 3 supplement 2.3 81 4 supplement 2.3 79

Subsequently, the individual regeneration solvents of the high purity electronic class finally recovered by the improved yield by performing the regeneration yield improvement method of Tables 3 and 4 according to the present invention under the distillation conditions of Table 2 with respect to the Example of Table 1 above. Table 5 shows the results of the content analysis.

SPEC. Example 1 Example 2 Example 3 Example 4 water(%) MEA 99.5 or more - 99.5 ≤ 99.6 ≤ NMP 99.6 ≤ - BDG 99.6 ≤ 99.7 ≤ Moisture content (%) 0.1 or less ≤ 0.1 ≤ 0.1 ≤ 0.1 Total metal content (ppb) 500 or less ≤ 500 ≤ 500 ≤ 500

1 is a schematic diagram showing an embodiment of a reproducing yield enhancing process of the present invention used for reproducing a photoresist stripper according to the present invention.

Brief description of the symbols in the drawings

T-1: Raw Material Supply Tank

T-2: Impurity Collection Tank

T-3, T-4, T-5: Regenerative Stripper Solvent Storage Tank

1-1, 1-2, 2-1, 2-2, 2-3, 2-4, 2-5: transfer pump

3: condenser

4: temporary storage tank

5: top low

6: re-sweep

6a: Reheating Fruit Line Tube

7: gas chromatography

8: ultraviolet absorbance photometer

7a, 8a: controller

9, 10, 13: flow control valve

11: N-methyl pyrrolidone supply tank

12: load cell

14: decompression pump

15: second distillation column

Claims (10)

The photoresist stripper waste liquid is distilled from the photoresist stripper regeneration apparatus including a photoresist stripper waste liquid supply device, a distillation column connected to the supply device, a reboiler connected to the bottom of the distillation column, and a condenser connected to the top of the distillation column. In the process of playing, The method of improving the photoresist stripper regeneration yield, characterized in that the concentration of the photoresist resin is adjusted to be below the maximum saturation concentration at which the dissolved photoresist resin contained in the distillation residue of the photoresist stripper waste liquid supplied into the reboiler. . The method of claim 1, In order to adjust the concentration of the photoresist resin, The saturation concentration at which the dissolved photoresist resin, which is present in the bottom of the reboiler, the distillation column or the distillation residue of the connection pipe between the reboiler and the column bottom, is precipitated as a solidifying component, and the reboiling level at the saturation concentration is determined to be the first lowest. Determining the water level; And Supplying the photoresist stripper waste liquid to a distillation column to maintain the level of the distillation residue in the reboiler at a first minimum level; Photoresist stripper regeneration yield enhancement method comprising a. The method of claim 2, The photoresist resin concentration measurement method of the photoresist stripper regeneration yield, characterized in that measured by the ultraviolet absorbance method. The method of claim 2, Supplying the photoresist stripper waste liquid to the distillation column to perform a regeneration process comprising maintaining the level of the distillation residue in the reboiler at or above the first minimum level; A photoresist stripper effluent that is a reference containing a specific concentration of N-methyl pyrrolidone to obtain a desired recovery rate, and used for regeneration comprising an N-methyl pyrrolidone at any concentration lower than the specific concentration. Comparing the weight ratio of photoresist to N-methyl pyrrolidone content by analyzing the N-methyl pyrrolidone content contained in the distillation residue at the first lowest water level for the photoresist stripper waste liquid, respectively; When the N-methyl pyrrolidone was further added, the N-methyl pyrrolidone was additionally supplied through a reboiler so that the reference photoresist stripper waste liquid used as the reference and the photoresist stripper waste liquid used for regeneration are in the same weight ratio. Determining the non-gas level as the second lowest level; And Feeding N-methyl pyrrolidone to the reboiler to maintain the level of the distillation residue in the reboiler above a second lowest level; The photoresist stripper regeneration yield enhancement method comprising a further. The method of claim 1, In order to adjust the concentration of the photoresist resin, The saturation concentration at which the dissolved photoresist resin, which is present in the bottom of the reboiler, the distillation column or the distillation residue of the connection pipe between the reboiler and the column bottom, is precipitated as a solidifying component, and the reboiling level at the saturation concentration is determined to be the first lowest. Determining the water level; A photoresist stripper effluent that is a reference containing a specific concentration of N-methyl pyrrolidone to obtain a desired recovery rate, and used for regeneration comprising an N-methyl pyrrolidone at any concentration lower than the specific concentration. Comparing the weight ratio of photoresist to N-methyl pyrrolidone content by analyzing the N-methyl pyrrolidone content contained in the distillation residue at the first lowest water level for the photoresist stripper waste liquid, respectively; When N-methyl pyrrolidone was additionally supplied through the reboiler so that the photoresist stripper waste liquid used as the reference and the photoresist stripper waste liquid used for regeneration become the same weight ratio, the ash when the N-methyl pyrrolidone was added Determining the non-gas level as the second lowest level; And Feeding N-methyl pyrrolidone to the reboiler to maintain the level of the distillation residue in the reboiler above a second lowest level; Photoresist stripper regeneration yield enhancement method comprising a. The method according to claim 4 or 5, The N-methyl pyrrolidone content is measured by the gas chromatography method. The method according to claim 4 or 5, The content of N-methyl pyrrolidone contained in the photoresist stripper waste liquid, which is the reference, is 5 to 40% by weight. The method according to claim 4 or 5, The additionally supplied N-methyl pyrrolidone is industrial grade method for improving the photoresist stripper regeneration yield. The method according to any one of claims 1 to 5, And removing the low boiling point impurities prior to regenerating the stripper solvent composition from the photoresist stripper waste liquid. The method according to any one of claims 1 to 5, And distilling the stripper solvent composition sequentially to regenerate the individual stripper solvents.

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