Purification processing apparatus, substrate processing system, and processing method

Abstract

To provide a purification processing apparatus, a substrate processing system, and a processing method for purifying IPA.SOLUTION: A purification processing apparatus that supplies refined isopropyl alcohol to a substrate processing apparatus includes a processing container that mixes isopropyl alcohol before purification and an ionic liquid and separates the isopropyl alcohol and the ionic liquid to purify the isopropyl alcohol, a pre-purification solvent supply port that supplies the isopropyl alcohol before purification to the processing container, an ionic liquid supply port that supplies the ionic liquid to the processing container, and a post-purification solvent outlet that supplies the purified isopropyl alcohol from the processing container to the substrate processing apparatus.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a refinement processing apparatus, a substrate processing system, and a processing method. [Background technology]

[0002] Patent Document 1 discloses a substrate processing apparatus that cleans wafers by supplying a chemical solution to the wafers. In this substrate processing apparatus, dilute hydrofluoric acid (DHF solution) is discharged onto the wafers, and the wafers are subjected to chemical cleaning using the DHF solution. Next, pure water (rinse solution) is discharged onto the wafers, and a rinse process is performed. After that, isopropyl alcohol (IPA) is supplied onto the wafers, and the wafers are dried. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-21597 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a purification processing apparatus, a substrate processing system, and a processing method for purifying IPA. [Means for solving the problem]

[0005] In order to solve the above problems, according to one aspect, there is provided a purification processing apparatus that supplies purified isopropyl alcohol to a substrate processing apparatus, the purification processing apparatus comprising: a processing vessel that mixes unpurified isopropyl alcohol with an ionic liquid and separates the isopropyl alcohol from the ionic liquid to purify the isopropyl alcohol; a pre-purification solvent supply port that supplies the unpurified isopropyl alcohol to the processing vessel; an ionic liquid supply port that supplies the ionic liquid to the processing vessel; and a purified solvent outlet that supplies the purified isopropyl alcohol from the processing vessel to the substrate processing apparatus. The ionic liquid has a higher specific gravity than the isopropyl alcohol.A refinery processing system is provided. [Effects of the Invention]

[0006] According to one aspect, a purification processing apparatus, a substrate processing system, and a processing method for purifying IPA can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a configuration of a substrate processing system according to an embodiment of the present invention. [Figure 2] 1 is a schematic cross-sectional view illustrating an example of a configuration of a purification treatment device. [Figure 3] 1 is an example of a flowchart illustrating the operation of the refining treatment device. [Figure 4] FIG. 1 is a schematic diagram illustrating IPA purification using an ionic liquid. [Figure 5] 1 is a graph showing an example of the results of metal removal using an ionic liquid. [Figure 6] FIG. 10 is another example of a schematic cross-sectional view illustrating the configuration of the purification treatment device. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] FIG. 1 is a diagram illustrating an example of the configuration of a substrate processing system 1 according to this embodiment.

[0010] The substrate processing system 1 includes a substrate processing apparatus 10, a purification processing apparatus 20, an IPA supplying apparatus 30, and an ionic liquid supplying apparatus 40.

[0011] The substrate processing apparatus 10 is, for example, a cleaning apparatus for cleaning wafers. The substrate processing apparatus 10 includes, for example, a spin chuck, a cleaning liquid supply unit, a rinse liquid supply unit, a drying liquid supply unit, and an inert gas supply unit. The spin chuck holds and rotates a wafer. The cleaning liquid supply unit supplies a cleaning liquid (e.g., diluted hydrofluoric acid (DHF (Diluted Hydrofluoric Acid) liquid: a dilute hydrogen fluoride aqueous solution)) to the wafer held by the spin chuck. Note that the cleaning liquid is not limited to an acidic cleaning liquid containing dilution hydrofluoric acid, and organic solvents such as resist strippers and acetone solvents may also be used. The rinse liquid supply unit supplies a rinse liquid (e.g., pure water) to the wafer held by the spin chuck. The drying liquid supply unit supplies a drying liquid (isopropyl alcohol, hereinafter referred to as IPA) to the wafer held by the spin chuck. The inert gas supply unit supplies an inert gas (e.g., N2 gas) to the wafer held by the spin chuck.

[0012] The substrate processing apparatus 10 cleans wafers by performing a chemical processing step, a rinsing step, and a drying step. In the chemical processing step, a cleaning chemical (e.g., DHF liquid) is supplied to the wafer while the spin chuck holds and rotates the wafer. This forms a liquid film of the chemical liquid on the surface of the wafer, performing chemical processing. In the rinsing step, a rinse liquid (e.g., pure water) is supplied to the wafer while the spin chuck holds and rotates the wafer. This washes away any remaining chemical liquid on the wafer surface, forming a liquid film of the pure water on the wafer surface. In the drying step, a drying liquid (IPA) is supplied to the wafer while the spin chuck holds and rotates the wafer. This washes away any remaining rinse liquid on the wafer surface, forming a liquid film of the drying liquid on the wafer surface. Thereafter, the supply of the drying liquid is stopped, the wafer is rotated, and the drying liquid is shaken off from the wafer surface. Furthermore, an inert gas (e.g., N2 gas) is sprayed onto the wafer to dry it.

[0013] The purification processing device 20 purifies the IPA. Specifically, the purification processing device 20 purifies the IPA by removing trace amounts of water and impurities such as metals contained in the IPA. The purification processing device 20 then supplies the purified IPA to the substrate processing device 10 (drying liquid supply unit).

[0014] The IPA supplying device 30 supplies IPA (isopropyl alcohol) to the purification processing device 20.

[0015] The ionic liquid supplying device 40 supplies an ionic liquid to the purification processing device 20. Examples of ionic liquids that can be used include N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (hereinafter referred to as "DEME-BF4"), 1-allyl-3-ethylimidazolium tetrafluoroborate (hereinafter referred to as "AEIm-BF4"), 1-allyl-3-methylimidazolium tetrafluoroborate (hereinafter referred to as "AMIm-BF4"), and 1-ethyl-3-methylimidazolium tetrafluoroborate (hereinafter referred to as "EMIm-BF4").

[0016] The substrate processing apparatus 10 and the purification processing apparatus 20 are connected by a flow path 21, and IPA recovered from the substrate processing apparatus 10 is supplied to the purification processing apparatus 20. The IPA supplying apparatus 30 and the purification processing apparatus 20 are connected by a flow path 22, and IPA is supplied from the IPA supplying apparatus 30 to the purification processing apparatus 20. The ionic liquid supplying apparatus 40 and the purification processing apparatus 20 are connected by a flow path 23, and ionic liquid is supplied from the ionic liquid supplying apparatus 40 to the purification processing apparatus 20. The purification processing apparatus 20 and the substrate processing apparatus 10 (drying liquid supply section) are connected by a flow path 24, and IPA purified in the purification processing apparatus 20 is supplied to the substrate processing apparatus 10 (drying liquid supply section). A flow path 25 is connected to the purification processing apparatus 20, and waste liquid is discharged.

[0017] Next, the refinement processing device 20 will be further described with reference to Fig. 2. Fig. 2 is an example of a cross-sectional schematic diagram illustrating the configuration of the refinement processing device 20.

[0018] The purification processing device 20 includes a processing container 210 , temperature adjustment mechanisms 221 and 222 , a stirring mechanism 230 , on-off valves 241 to 245 , and a control unit 260 .

[0019] The processing vessel 210 is supplied with unpurified IPA and ionic liquid, and the IPA is purified within the processing vessel 210. The processing vessel 210 also supplies the purified IPA to the substrate processing apparatus 10 (drying liquid supply unit).

[0020] The processing vessel 210 is connected to the flow path 21 and has a pre-purification solvent inlet that supplies pre-purification IPA to the processing vessel 210. The processing vessel 210 is also connected to the flow path 22 and has a pre-purification solvent supply port that supplies pre-purification IPA to the processing vessel 210. The processing vessel 210 is also connected to the flow path 23 and has an ionic liquid supply port that supplies ionic liquid to the processing vessel 210.

[0021] Here, the ionic liquid is insoluble in IPA. Furthermore, the ionic liquid has a higher specific gravity than IPA. Therefore, when the solution 250 containing IPA and the ionic liquid supplied to the processing vessel 210 is allowed to stand, it separates into an upper IPA layer 251 and a lower ionic liquid layer 252, as shown in FIG. 2.

[0022] The processing vessel 210 also has a purified solvent outlet connected to the flow path 24, which discharges the purified IPA from the processing vessel 210 to the substrate processing apparatus 10 (drying liquid supply unit). The purified solvent outlet is provided on the upper side of the side wall of the processing vessel 210 so as to recover the upper solution (IPA layer 251) of the two-layer solution 250 separated from the processing vessel 210.

[0023] Furthermore, the processing vessel 210 is connected to the flow path 25 and has a waste liquid outlet for discharging the treated ionic liquid (waste liquid) from the processing vessel 210. Here, the waste liquid outlet is provided on the bottom surface of the processing vessel 210 so as to recover the lower solution (ionic liquid layer 252) of the two-layer solution obtained when the solution 250 in the processing vessel 210 is separated.

[0024] The temperature adjustment mechanism 221 adjusts the temperature of the solution 250 contained in the processing vessel 210. The temperature adjustment mechanism 222 adjusts the temperatures of the unpurified IPA and the ionic liquid supplied to the processing vessel 210 via the flow paths 21 to 23. The operations of the temperature adjustment mechanisms 221 and 222 are controlled by the control unit 260.

[0025] The stirring mechanism 230 stirs the solution 250 contained in the processing vessel 210. That is, the stirring mechanism 230 stirs the upper IPA layer 251 and the lower ionic liquid layer 252 to mix the IPA and the ionic liquid. The operation of the stirring mechanism 230 is controlled by the control unit 260.

[0026] The on-off valve 241 is provided in the flow path 21. The on-off valve 242 is provided in the flow path 22. The on-off valve 243 is provided in the flow path 23. The on-off valve 244 is provided in the flow path 24. The on-off valve 245 is provided in the flow path 25. The operations of the on-off valves 241 to 245 are controlled by the control unit 260.

[0027] The control unit 260 controls the operation of the temperature adjustment mechanisms 221 and 222, the stirring mechanism 230, and the on-off valves 241 to 245, thereby controlling the operation of the entire refinement processing device 20.

[0028] Next, the purification process of IPA by the purification processing device 20 will be described with reference to Fig. 3. Fig. 3 is an example of a flowchart illustrating the operation of the purification processing device 20.

[0029] In step S101, the control unit 260 opens the on-off valve 242 and the on-off valve 243 to supply the unpurified IPA and the ionic liquid to the processing vessel 210. The control unit 260 may open the on-off valve 241 to supply the IPA recovered from the substrate processing apparatus 10 to the processing vessel 210. The control unit 260 may also control the temperature adjustment mechanism 222 to adjust the temperatures of the unpurified IPA and the ionic liquid supplied to the processing vessel 210. When the supply of the IPA and the ionic liquid to the processing vessel 210 is completed, the control unit 260 closes the on-off valve 242 (241) and the on-off valve 243.

[0030] In step S102, the control unit 260 operates the stirring mechanism 230 to stir the solution 250 containing IPA and the ionic liquid in the processing container 210. When the stirring is completed, the control unit 260 stops the operation of the stirring mechanism 230.

[0031] In step S103, the control unit 260 stops the stirring mechanism 230 and allows the solution 250 to stand still, thereby separating the IPA layer 251 and the ionic liquid layer 252.

[0032] Here, the control unit 260 may control the temperature adjustment mechanism 221 to cool (adjust the temperature) the solution 250 to a temperature at which the IPA layer 251 and the ionic liquid layer 252 are separated. Alternatively, the control unit 260 may control the temperature adjustment mechanism 221 to cool or heat (adjust the temperature) the solution 250 based on the temperature of the IPA supplied to the substrate processing apparatus 10.

[0033] As a result, trace amounts of water and metals contained in the IPA before purification move to the ionic liquid layer 252, and the water and metals can be removed (purified) from the IPA in the IPA layer 251.

[0034] In step S104, the control unit 260 opens the on-off valve 244 to supply the purified IPA from the IPA layer 251 to the substrate processing apparatus .

[0035] The ionic liquid may be reused multiple times. By opening the on-off valve 245, the IPA and the ionic liquid containing water and metals can be discharged from the processing container 210 as waste liquid.

[0036] 4 is a schematic diagram illustrating the purification of IPA using an ionic liquid. Here, the removal of trace amounts of metals contained in IPA before purification is described as an example.

[0037] Metals to be removed 251a are contained in IPA layer 251 containing IPA before purification, and ionic liquid layer 252 contains ionic liquid components 252a such as anions and cations.

[0038] By stirring the IPA and the ionic liquid, the ionic liquid component 252a and the metal to be removed 251a come into contact with each other, forming, for example, a complex 252b. The bonding structure between the metal to be removed 251a and the ionic liquid component 252a is not limited to a complex. Then, by leaving the solution 250 to stand (and cooling), the solution separates into an IPA layer 251 and an ionic liquid layer 252, and the complex 252b is contained in the ionic liquid layer 252. This allows the metal to be removed 251a from the IPA layer 251.

[0039] 4, the removal of metals from IPA has been described as an example, but the present invention is not limited to this. Trace amounts of water contained in IPA before purification can also be removed from IPA using an ionic liquid.

[0040] Figure 5 is a graph showing an example of the results of metal removal using an ionic liquid. Here, a metal standard solution (a solution in which 100 ppb of each metal was dissolved in 5% nitric acid) was added to IPA to create contaminated IPA. Next, 10 ml of DEME-BF4 (an ionic liquid) was added to 30 ml of the contaminated IPA, stirred, cooled, and allowed to stand, resulting in separation into an upper layer of IPA and a lower layer of ionic liquid. Each liquid was sampled, and mass analysis of each metal atom was performed using ICP-MS.

[0041] In the graph of Figure 5, "unseparated at room temperature" indicates the results for the liquid after stirring, "upper layer cooled" indicates the results for IPA after separation by cooling and standing still, and "lower layer cooled" indicates the results for the ionic liquid after separation by cooling and standing still.

[0042] As shown in Figure 5, for metal elements other than Fe, the amount of metal detected was greater in the lower layer than in the upper layer. Furthermore, for metal elements other than Cr, the amount detected was lower in the upper layer after separation than before separation. This indicates that when IPA and the ionic liquid separate, metals migrate to the lower layer, and the effect of metal removal is achieved in the upper layer.

[0043] 5 shows an example in which DEME-BF4 is used as the ionic liquid, but the present invention is not limited to this. By selecting a suitable ionic liquid depending on the metal to be removed from IPA, the target metal can be suitably removed from IPA.

[0044] As described above, according to the substrate processing system 1 of this embodiment, trace amounts of moisture and metals in IPA can be removed (purified) in the purification processing device 20, and the purified IPA can be supplied to the substrate processing device .

[0045] Here, when purifying IPA, a common high-purity method is known in which, for example, IPA is heated and the target metal contaminants are chelated (complexed) using the vapor pressure difference between IPA and impurities, and then distilled off. In contrast, the IPA purification method using the purification processing device 20 allows IPA to be purified without heating IPA to a temperature at which it must be distilled. As a result, the substrate processing system 1 according to this embodiment allows IPA to be purified without heating IPA, which is flammable and highly volatile, to a high temperature. Furthermore, by using an ionic liquid that is flame-retardant and non-volatile (or has a sufficiently low volatility), the impact on nearby devices can be minimized.

[0046] Furthermore, in a configuration in which high-purity IPA is purified at a location away from the apparatus (substrate processing apparatus 10) that uses IPA and transported using tanks, piping, etc., there is a risk of the purity of the IPA deteriorating during transport. In contrast, in the substrate processing system 1 according to this embodiment, the purification processing apparatus 20 can be installed at a location close to the apparatus (substrate processing apparatus 10) that uses IPA, so that the purity of the IPA can be prevented from deteriorating during transport from the purification processing apparatus 20 to the substrate processing apparatus 10.

[0047] Furthermore, ionic liquids have high thermal stability and can be suitably used even when the apparatus (substrate processing apparatus 10) using IPA is in a vacuum process environment.

[0048] In FIG. 2, the refining processing apparatus 20 is described as supplying refined IPA to the substrate processing apparatus 10, but the present invention is not limited to this.

[0049] FIG. 6 is another example of a cross-sectional schematic diagram illustrating the configuration of the purification processing device 20. As described above with reference to FIG. 4 and other figures, impurities such as water in IPA are absorbed into the ionic liquid. The ionic liquid also prevents the impurities absorbed in the ionic liquid from returning to the IPA. Furthermore, the ionic liquid has high thermal stability and does not evaporate, even in a vacuum process environment, for example. Therefore, even if the ionic liquid containing impurities remains in the IPA, it may not adversely affect subsequent processing. In such cases, as shown in FIG. 6, the purification processing device 20 may be configured to supply a solution 250, a mixture of IPA and ionic liquid, to another device.

[0050] The embodiments of the present disclosure should be considered in all respects as illustrative and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0051] 1. Substrate Processing System 10. Substrate processing equipment 20 Refining and Processing Equipment 21~25 Channels 30 IPA supply device 40 Ionic liquid supply device 210 Processing vessel 221,222 Temperature control mechanism 230 Stirring mechanism 241~245 On-off valve 250 solution 251 IPA layer 252 Ionic Liquid Layer

Claims

1. A purification processing apparatus for supplying purified isopropyl alcohol to a substrate processing apparatus, A treatment vessel in which the isopropyl alcohol before purification is mixed with an ionic liquid and the isopropyl alcohol is separated from the ionic liquid to purify the isopropyl alcohol; a pre-purification solvent supply port for supplying the isopropyl alcohol before purification to the treatment vessel; an ionic liquid supply port for supplying the ionic liquid to the processing vessel; a purified solvent outlet for supplying the purified isopropyl alcohol from the processing vessel to the substrate processing apparatus, The ionic liquid has a higher specific gravity than the isopropyl alcohol. Refining processing equipment.

2. a waste liquid discharge port for discharging the ionic liquid from the treatment vessel, The refining treatment device according to claim 1 .

3. a stirring mechanism for stirring the isopropyl alcohol and the ionic liquid in the processing vessel; The refining treatment device according to claim 1 or 2.

4. A temperature adjustment unit is provided to adjust the temperature of the isopropyl alcohol and the ionic liquid. The refining treatment device according to any one of claims 1 to 3.

5. The temperature adjustment unit adjusts the temperature of the isopropyl alcohol and the ionic liquid before purification supplied to the treatment container. The refining treatment device according to claim 4 .

6. The temperature adjustment unit adjusts the temperature of the isopropyl alcohol and the ionic liquid in the processing container. The refining treatment device according to claim 5 .

7. The unpurified solvent supply port is supplied with the unpurified isopropyl alcohol from a tank that stores the unpurified isopropyl alcohol. The refining treatment device according to any one of claims 1 to 6.

8. the unpurified solvent supply port is supplied with the isopropyl alcohol recovered in the substrate processing apparatus. The refining treatment device according to any one of claims 1 to 7.

9. The ionic liquid is any one of DEME-BF4, AEIm-BF4, AMIm-BF4, and EMIm-BF4. The refining treatment device according to any one of claims 1 to 8.

10. A substrate processing system comprising the substrate processing apparatus and the purification processing apparatus according to claim 1 .

11. mixing metal-containing isopropyl alcohol with an ionic liquid; separating the isopropyl alcohol from the ionic liquid; and supplying the separated isopropyl alcohol to another device. The ionic liquid has a higher specific gravity than the isopropyl alcohol. Processing method.

12. The step of separating the isopropyl alcohol from the ionic liquid includes: The mixed isopropyl alcohol and the ionic liquid are cooled and allowed to stand. The method of claim 11.

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