EBR solvent and rectification preparation process thereof

Abstract

The invention discloses an EBR solvent and a rectification preparation process thereof, and belongs to the technical field of semiconductor material processing. Wherein the EBR solvent comprises the following components in percentage by weight: 95%-98% of propylene glycol methyl ether acetate and 2%-5% of propylene glycol methyl ether. The EBR solvent is prepared by rectifying and recycling waste liquid generated in a diluting and cleaning process. The method mainly comprises the following steps: S1, settling and filtering: filtering the waste liquid to obtain solid impurities; s2, preliminary water removal: removing a part of water in the filtered waste liquid through a common distillation retort to obtain a primary waste liquid raw material; s3, feeding: introducing the primary waste liquid raw material into a rectifying tower for intermittent distillation and purification; s4, water removal: removing water in the primary waste liquid raw material by using an extraction agent; s5, refluxing the extracting agent; s6, extracting an extracting agent: extracting the extracting agent after water is completely removed; and S7, extracting the EBR solvent. The invention solves the problem of poor recycling effect caused by low purity of the effective component EBR solvent in the photoresist cleaning waste liquid at present.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor material processing, and in particular relates to an EBR solvent and a distillation preparation process thereof. Background Art

[0002] During the process of coating and leveling in the semiconductor photolithography process, due to the effect of centrifugal force, the thickness of the photoresist at the edge of the wafer will be thicker, generally several times the normal film thickness, and accumulate at the edge to form ridges, which can easily contaminate the photoresist exposure equipment and the bottom surface of the wafer; therefore, a diluent is required to clean the photoresist on the edge and back of the wafer to avoid environmental and equipment pollution in subsequent processes; the process of removing the raised photoresist on the edge of the wafer is called EBR (Edge Bead Removal); it is also called the photoresist edge glue line removal process; the solvent used to dilute and clean the photoresist can also be called EBR solvent; the composition and ratio of the EBR solvent are related to the degree of cleaning of the photoresist.

[0003] After EBR solvent is diluted and cleaned, it is called diluted waste liquid. The EBR solvent components in the diluted waste liquid have not changed. After the components in the EBR solvent are purified again from the diluted waste liquid, it can be reused; however, the purity after purification affects the cleaning effect of the EBR solvent on the photoresist when it is used again and whether it will affect the wafer itself; the recovery rate through ordinary distillation purification technology is low, and its recovered purity makes its cleaning effect on the photoresist poor when it is used again. Summary of the invention

[0004] The present invention provides an EBR solvent and a distillation preparation process thereof, wherein the EBR solvent is prepared by using a mixed solvent obtained by using propylene glycol methyl ether acetate (PGMEA) and propylene glycol methyl ether (PGME) in a specific ratio; the diluted waste liquid is purified by intermittent distillation, and before the intermittent distillation, a part of the water in the waste diluted liquid is first removed by a distillation tank, so as to shorten the time of the subsequent intermittent distillation, and the recovery purity of the EBR solvent is improved by setting and controlling the temperature and reflux ratio parameters. The present invention solves the problem that the purity of the EBR solvent, an effective component in the photoresist cleaning waste liquid, is not high, resulting in poor recycling and reuse effects.

[0005] In order to achieve the above technical objectives, the present invention is implemented by the following technical solutions:

[0006] An EBR solvent comprising the following components in the following percentages:

[0007] Propylene glycol methyl ether acetate 95%~98%, propylene glycol methyl ether 2%~5%.

[0008] Preferably, in the EBR solvent, the components are calculated as follows in percentage:

[0009] Propylene glycol methyl ether acetate 97%, propylene glycol methyl ether 3%.

[0010] Another object of the present invention is to provide a distillation preparation process of an EBR solvent, comprising the following steps:

[0011] S1: Sedimentation filtration: After the waste liquid passes through the filter to remove solid waste, it enters the raw material sedimentation kettle and is left to settle to remove solid impurities;

[0012] S2: Preliminary water removal: The supernatant after sedimentation enters the distillation tank, the waste liquid is heated, part of the water in it turns into steam and enters the water collection tank after condensation, the water is continuously collected from the bottom of the water collection tank, and a small amount of EBR effective components taken out from the upper layer are returned to the distillation tank;

[0013] S3: Feeding: The primary waste liquid raw material mixed with the extractant enters the bottom of the distillation tower together, and the bottom heating device is turned on;

[0014] S4: Water removal: After the primary waste liquid raw material in the tower kettle is heated, the extractant and the remaining water in the raw material are first vaporized and enter the heat exchange condenser from the top of the tower; the condensed extractant and water enter the collection tank; the extractant and water are layered in the collection tank, with the extractant concentrated in the upper layer and the water concentrated in the lower layer; then the water is discharged from the bottom of the collection tank;

[0015] S5: Extractant reflux: the extractant in the upper layer is refluxed into the distillation tower for reuse;

[0016] S6: Extracting the extractant: Repeat S4 and S5 until the mass fraction of water in the collection tank is reduced to below 0.1% and the mass fraction of the extractant is greater than 99.9%;

[0017] extracting the extractant from the collection tank;

[0018] S7: Extracting EBR solvent: close the reflux pipeline between the collection tank and the distillation tower; increase the temperature to heat the EBR liquid in the distillation tower; vaporize it and let it enter the heat exchange condenser from the top of the tower;

[0019] The condensed EBR solution enters the storage tank for collection.

[0020] Preferably, the heating temperature of the distillation tank in S2 is controlled at 90-110° C.;

[0021] When the liquid level of the primary waste liquid raw material in the distillation tank reaches 80% to 90%, the raw material starts to be fed into the distillation tower.

[0022] Preferably, the heating temperature of the tower bottom in S4 is controlled at 100-120°C.

[0023] Preferably, the reflux ratio in S5 is controlled at 2-5:1.

[0024] Preferably, when the reflux ratio in S6 is close to 0.99:1; after exhausting the last extraction agent vapor, the reflux pipeline valve between the collection tank and the distillation tower is closed, and the pipeline valve between the storage tank and the distillation tower is opened.

[0025] Preferably, the heating temperature of the tower bottom in S7 is controlled to be increased to 150-160° C., so that both PGMEA and PGME in the EBR solution are gasified.

[0026] Preferably, the extractant comprises: one of toluene, xylene, benzyl alcohol and cyclohexane.

[0027] The beneficial effects of the present invention are:

[0028] The EBR solvent provided by the present invention comprises two components, PGMEA and PGME. After the two components are mixed according to the ratio of the present invention, the photoresist on the back and edge of the wafer can be optimally cleaned.

[0029] The present invention provides a method for purifying EBR solvent from diluted waste liquid. By using intermittent distillation technology, water in the waste liquid is first removed in batches, and EBR solvent with higher purity remains. The reflux ratio in the distillation process is controlled to improve the recovery purity of the EBR solvent.

[0030] Before entering the distillation tower for intermittent distillation, the temperature in the distillation tank is controlled and ordinary distillation is used to remove part of the water, thereby shortening the time for obtaining the product in the subsequent intermittent distillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0032] Figure 1 It is a schematic diagram of the distillation preparation process technology route of the EBR solvent of the present invention;

[0033] Figure 2 The present invention is a flowchart of the distillation process for preparing the EBR solvent.

[0034] In the accompanying drawings, the components represented by the reference numerals are:

[0035] 1-distillation tank, 2-distillation tower, 3-heat exchanger, 4-collection tank, 5-storage tank, 6-water collection tank. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides an EBR solvent, comprising the following components in the following percentages:

[0039] Propylene glycol methyl ether acetate 97%, propylene glycol methyl ether 3%.

[0040] Prepare EBR cleaning solution: take a certain amount of EBR solvent and mix it with water, the ratio of EBR solvent to water is 1:1; pour the prepared EBR cleaning solution into the spray bottle;

[0041] After soft-baking the raised photoresist on the edge of the wafer, spray the EBR cleaning liquid evenly on the raised photoresist surface on the edge of the wafer, and be careful not to spray it in the effective area of ​​the photoresist; let it stand for 5 to 10 minutes after spraying to allow the EBR cleaning liquid to fully contact and react with the photoresist; then clean the edge of the wafer and wipe it clean; observe and record the changes in the thickness of the photoresist film at the edge of the wafer after cleaning.

[0042] Comparative Example 1

[0043] This comparative example provides an EBR solvent, comprising the following components in the following percentages:

[0044] Propylene glycol methyl ether acetate 95%, propylene glycol methyl ether 5%.

[0045] Prepare EBR cleaning solution: according to the EBR solvent component ratio of this comparative example, take an equal amount of EBR solvent and water as in Example 1 and mix them thoroughly, and the ratio of EBR solvent to water is also 1:1; pour the prepared EBR cleaning solution into a spray pot;

[0046] After soft-baking the raised photoresist on the edge of the wafer, spray the EBR cleaning liquid evenly on the raised photoresist surface on the edge of the wafer, and be careful not to spray it in the effective area of ​​the photoresist; let it stand for 5 to 10 minutes after spraying to allow the EBR cleaning liquid to fully contact and react with the photoresist; then clean the edge of the wafer and wipe it clean; observe and record the changes in the thickness of the photoresist film at the edge of the wafer after cleaning.

[0047] Comparative Example 2

[0048] This comparative example provides an EBR solvent, comprising the following components in the following percentages:

[0049] Propylene glycol methyl ether acetate 98%, propylene glycol methyl ether 2%.

[0050] Prepare EBR cleaning solution: according to the EBR solvent component ratio of this comparative example, take an equal amount of EBR solvent and water as in Example 1 and mix them thoroughly, and the ratio of EBR solvent to water is also 1:1; pour the prepared EBR cleaning solution into a spray pot;

[0051] After soft-baking the raised photoresist on the edge of the wafer, spray the EBR cleaning liquid evenly on the raised photoresist surface on the edge of the wafer, and be careful not to spray it in the effective area of ​​the photoresist; let it stand for 5 to 10 minutes after spraying to allow the EBR cleaning liquid to fully contact and react with the photoresist; then clean the edge of the wafer and wipe it clean; observe and record the changes in the thickness of the photoresist film at the edge of the wafer after cleaning.

[0052] Table 1 Wafer edge ridge photoresist cleaning effect record

[0053]

[0054] Conclusion analysis: From the recorded data in Table 1, it can be concluded that the initial photoresist thickness of the wafer edge selected in the three groups of experiments is 100 μm, the ratio of EBR solvent to water in the EBR cleaning solution in the three groups is 1:1, the concentration of the EBR cleaning solution is the same, and the cleaning reaction time of the three groups is the same; after the EBR cleaning solution prepared by the EBR solvent ratio in Example 1 is used to clean the photoresist raised on the edge of the wafer, the thickness of the photoresist raised on the edge is only 0.52 μm; the EBR solvent ratio prepared in Comparative Example 1 is 0.03 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.02 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.03 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.06 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.08 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.09 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.06 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.08 ...9 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.06 μm, and the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 1 is 0.0 After the EBR cleaning solution cleaned the photoresist raised on the edge of the wafer, the thickness of the edge raised photoresist was 2.58 μm; after the EBR cleaning solution prepared by the EBR solvent ratio in Comparative Example 2 cleaned the photoresist raised on the edge of the wafer, the thickness of the edge raised photoresist was 3.05 μm; so Example 1 completed the dissolution and cleaning of the photoresist with a thickness of 99.48 μm; Comparative Example 1 completed the dissolution and cleaning of the photoresist with a thickness of 97.42 μm; Comparative Example 2 completed the dissolution and cleaning of the photoresist with a thickness of 96.95 μm;

[0055] It can be seen that, with the same EBR cleaning solution concentration and the same reaction time, the cleaning effect of the EBR cleaning solution prepared using the EBR solvent ratio in Example 1 is significantly better than that of Comparative Example 1 and Comparative Example 2.

[0056] Example 2

[0057] like Figure 1 As shown in the schematic diagram of the technical route, this embodiment provides a distillation preparation process of an EBR solvent, comprising the following steps:

[0058] S1: Sedimentation filtration: After the waste liquid passes through the filter to remove solid waste, it enters the raw material sedimentation kettle and is left to settle to remove solid impurities;

[0059] S2: Preliminary water removal: The supernatant after sedimentation enters the distillation tank. Considering the different altitudes and boiling points, the waste liquid is heated at 90-110°C. In this embodiment, the supernatant can be heated at 110°C to make part of the water in the supernatant form steam and be discharged into the water collection tank after condensation to obtain the primary waste liquid raw material; water is continuously extracted from the bottom of the water collection tank, and a small amount of EBR effective components taken out from the upper layer are returned to the distillation tank;

[0060] Initially remove water until the liquid level in the distillation tank reaches 80%, and then start feeding into the distillation tower;

[0061] S3: Feeding: The primary waste liquid raw material mixed with the extractant enters the bottom of the distillation tower together, and the bottom heating device is turned on;

[0062] In this embodiment, toluene is used as an extractant; the primary waste liquid raw material mainly contains propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME) and water; after toluene is added, toluene and water are mixed, and the two can boil and vaporize at the same or similar temperature at the same time, thereby achieving the purpose of taking out moisture;

[0063] S4: Dehydration: Open the tower kettle and keep it heated at 100℃. This temperature can ensure that toluene and water are vaporized at the same time, but it does not reach the boiling point of PGMEA and PGME. The mixed vapor of toluene and water enters the heat exchange condenser from the top of the tower. The mixed vapor is condensed to form a mixed condensate and enters the collection tank.

[0064] Since toluene is incompatible with water, toluene is concentrated in the upper layer and water is concentrated in the lower layer in the collection tank; the water is discharged from the bottom of the collection tank into the water collection tank;

[0065] S5: Extractant reflux: Reflux the toluene in the upper layer of the collection tank to the distillation tower for reuse; during the reflux process, the reflux ratio needs to be controlled at 3:1; that is, reflux 3 parts of toluene and discharge 1 part of mixed gas; ensure that a sufficient amount of toluene refluxes to the distillation tower to mix with water, and ensure that a sufficient amount of water can be taken out after the two are azeotropic; shorten the drainage time and take out a sufficient amount of water at the same time, so that the less water in the mixed solvent of PGMEA and PGME, the higher the purity of the later purification;

[0066] S6: Extraction of extractant: Repeat the processes of S4 and S5 for many times, and the water content in the liquid in the distillation tank is gradually reduced; until the water mass fraction in the collection tank is reduced to below 0.1%, and the mass fraction of the extractant is greater than 99.9%; and when the reflux ratio is close to 0.99:1, it means that the water in the tank is completely removed; what comes out from the top of the distillation tank is toluene vapor; at this time, the heating temperature needs to be increased to 110°C, so that toluene is vaporized and discharged from the distillation tank alone, and reaches the collection tank after condensation, and the toluene solution is extracted;

[0067] S7: Extracting EBR solvent: After the toluene in the distillation tank is exhausted, close the reflux pipeline between the collecting tank and the distillation tower; increase the heating temperature of the tower bottom to 150-160°C; this temperature can vaporize both PGMEA and PGME in the distillation tower and discharge them from the top of the tower. After passing through the heat exchanger, a mixture of PGMEA and PGME is formed and condensed into a storage tank for collection, thus obtaining an EBR solvent product.

[0068] Purity test:

[0069] Gas chromatography was used to test the purity of EBR solvent;

[0070] 1) Take 10 ml of the EBR solvent prepared by the distillation preparation process provided in Example 2, add an appropriate amount of the internal standard solution, and mix well;

[0071] 2) injecting the mixed sample into the GC chromatograph using an automatic sample injector;

[0072] 3) Set up a suitable chromatographic column and carrier gas flow rate, and adjust the injection and discharge volumes;

[0073] 4) Turn on the chromatograph to analyze the results and record them.

[0074] Result analysis:

[0075] Through chromatographic analysis of the chromatogram, in the EBR solvent sample, the content of PGMEA component reached 97.41%; the content of PGME component reached 2.48%; the common purity of the two could reach 99.89%, achieving a relatively high recovery and purification degree.

[0076] Example 3

[0077] In this embodiment, the preliminary water removal step in the distillation tank is omitted, and the waste liquid is directly introduced into the distillation tower for direct distillation; the remaining steps are the same as in the embodiment, which are as follows:

[0078] S1: Sedimentation filtration: After the waste liquid passes through the filter to remove solid waste, it enters the raw material sedimentation kettle and is left to settle to remove solid impurities;

[0079] S2: Feeding: The primary waste liquid raw material mixed with the extractant enters the bottom of the distillation tower together, and the bottom heating device is turned on;

[0080] In this embodiment, toluene is used as an extractant; the primary waste liquid raw material mainly contains propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME) and water; after toluene is added, toluene and water are mixed, and the two can boil and vaporize at the same or similar temperature at the same time, thereby achieving the purpose of taking out moisture;

[0081] S3: Dehydration: Open the tower kettle and keep it heated at 100℃. This temperature can ensure that toluene and water are vaporized at the same time, but it does not reach the boiling point of PGMEA and PGME. The mixed vapor of toluene and water enters the heat exchange condenser from the top of the tower. The mixed vapor is condensed to form a mixed condensate and enters the collection tank.

[0082] Since toluene is incompatible with water, toluene is concentrated in the upper layer and water is concentrated in the lower layer in the collection tank; the water is discharged from the bottom of the collection tank into the water collection tank;

[0083] S4: Extractant reflux: The toluene on the upper layer of the collection tank is refluxed to the distillation tower for reuse; during the reflux process, the reflux ratio needs to be controlled at 3:1; that is, 3 parts of toluene are refluxed and 1 part of the mixed gas is discharged; ensure that a sufficient amount of toluene is refluxed to the distillation tower to mix with water, and ensure that a sufficient amount of water can be taken out after the two are azeotropic; shorten the drainage time and take out a sufficient amount of water at the same time, so that the less water in the mixed solvent of PGMEA and PGME, the higher the purity of the later purification;

[0084] S5: Extraction of extractant: Repeat the processes of S3 and S4 for many times, and the water content in the liquid in the distillation tank is gradually reduced; until the water mass fraction in the collection tank is reduced to below 0.1%, and the mass fraction of the extractant is greater than 99.9%; and when the reflux ratio is close to 0.99:1, it means that the water in the tank is completely removed; what comes out from the top of the distillation tank is toluene vapor; at this time, the heating temperature needs to be increased to 110°C, so that toluene is vaporized and discharged from the distillation tank alone, and reaches the collection tank after condensation, and the toluene solution is extracted;

[0085] S6: Extracting EBR solvent: After the toluene in the distillation tank is exhausted, close the reflux pipeline between the collecting tank and the distillation tower; increase the heating temperature of the tower bottom to 150-160°C; this temperature can vaporize both PGMEA and PGME in the distillation tower and discharge them from the top of the tower. After passing through the heat exchanger, a mixture of PGMEA and PGME is formed and condensed into a storage tank for collection, thus obtaining an EBR solvent product.

[0086] Result analysis:

[0087] Compared with Example 1, the method of directly distilling the filtered waste liquid in this embodiment is to achieve the same water removal effect in the waste liquid without replenishing the extractant in the middle; this embodiment needs to repeat the reflux operation 5 to 7 times more than the embodiment; this is because in addition to the fact that the water content in this embodiment is relatively high from the beginning of the distillation, the extractant will be lost every time it refluxes, so the more times the refluxes, the more the remaining extractant will gradually decrease in the later stage of the reflux, which will result in more repeated refluxes to achieve the purpose of removing water as much as possible.

[0088] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0089] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and use the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An EBR solvent, characterized in that Contains the following ingredients in the following percentages: Propylene glycol methyl ether acetate 95%~98%, propylene glycol methyl ether 2%~5%.

2. An EBR solvent according to claim 1, characterized in that: In the EBR solvent, the components are calculated as percentages: Propylene glycol methyl ether acetate 97%, propylene glycol methyl ether 3%.

3. A distillation preparation process for EBR solvent, characterized in that: The following steps are involved: S1: Sedimentation filtration: After the waste liquid passes through the filter to remove solid waste, it enters the raw material sedimentation kettle and is left to settle to remove solid impurities; S2: Preliminary water removal: The supernatant after sedimentation enters the distillation tank, the waste liquid is heated, part of the water in it turns into steam and enters the water collection tank after condensation, the water is continuously collected from the bottom of the water collection tank, and a small amount of EBR effective components taken out from the upper layer are returned to the distillation tank; S3: Feeding: The primary waste liquid raw material mixed with the extractant enters the bottom of the distillation tower together, and the bottom heating device is turned on; S4: Water removal: After the primary waste liquid raw material in the tower kettle is heated, the extractant and the remaining water in the raw material are first vaporized and enter the heat exchange condenser from the top of the tower; the condensed extractant and water enter the collection tank; the extractant and water are layered in the collection tank, with the extractant concentrated in the upper layer and the water concentrated in the lower layer; then the water is discharged from the bottom of the collection tank; S5: Extractant reflux: the extractant in the upper layer is refluxed into the distillation tower for reuse; S6: Extracting the extractant: Repeat S4 and S5 until the mass fraction of water in the collection tank is reduced to below 0.1% and the mass fraction of the extractant is greater than 99.9%; extracting the extractant from the collection tank; S7: Extracting EBR solvent: close the reflux pipeline between the collection tank and the distillation tower; increase the temperature to heat the EBR liquid in the distillation tower; vaporize it and let it enter the heat exchange condenser from the top of the tower; The condensed EBR solution enters the storage tank for collection.

4. The distillation preparation process of an EBR solvent according to claim 3, characterized in that: The heating temperature of the distillation tank in S2 is controlled at 90-110° C.; When the liquid level of the primary waste liquid raw material in the distillation tank reaches 80% to 90%, the raw material starts to be fed into the distillation tower.

5. The distillation preparation process of an EBR solvent according to claim 3, characterized in that: The heating temperature of the tower kettle in S4 is controlled at 100-120°C.

6. The distillation preparation process of an EBR solvent according to claim 3, characterized in that: The reflux ratio in S5 is controlled at 2-5:

1.

7. The distillation preparation process of an EBR solvent according to claim 3, characterized in that: When the reflux ratio in S6 is close to 0.99:1, after exhausting the last extraction agent steam, close the reflux pipeline valve between the collection tank and the distillation tower, and open the pipeline valve between the storage tank and the distillation tower.

8. The distillation preparation process of an EBR solvent according to claim 3, characterized in that: The heating temperature of the tower bottom in S7 is controlled to be raised to 150-160° C., so that both PGMEA and PGME in the EBR solution are gasified.

9. The distillation preparation process of an EBR solvent according to claim 3, characterized in that: The extractant comprises: one of toluene, xylene, benzyl alcohol and cyclohexane.

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