JP2009130032A - Substrate treating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treating apparatus capable of suppressing an excessive rise in siloxane concentration in an aqueous phosphoric acid solution in a treating tank. <P>SOLUTION: The aqueous phosphoric acid solution which is discharged from the treating tank and contains siloxane is cooled by a heat exchanger 51 and supplied to a reaction tank 60. The reaction tank 60 is fed with mixed liquid of dodecane and a TOPO extractant from a separatory tank 80, and the aqueous phosphoric acid solution and dodecane are mixed and stirred in the reaction tank 60, so that the siloxane in the aqueous phosphoric acid solution is extracted by the TOPO extractant and gets into the dodecane. Then the mixed liquid in the reaction tank 60 is sent out to a liquid-liquid centrifugal separator 70 to be centrifugally separated into the aqueous phosphoric acid solution having relatively large specific gravity and light liquid having small specific gravity and containing the dodecane and TOPO extractant. The separated aqueous phosphoric acid solution is fed to the treating tank again. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a semiconductor wafer on which a silicon oxide film and a silicon nitride film are formed, a glass substrate for a liquid crystal display device, a glass substrate for a photomask, a substrate for an optical disk, etc. (hereinafter simply referred to as “substrate”) in a phosphoric acid aqueous solution. The present invention relates to a substrate processing apparatus for selectively etching a silicon nitride film by being immersed in the substrate.

In the manufacturing process of a semiconductor device, an etching process is an important process for pattern formation. In particular, with the recent high performance and high integration of a semiconductor device, a silicon nitride film (Si ₃ film) formed on a substrate. A process of selectively etching away the silicon nitride film while leaving the silicon oxide film out of the (N ₄ film) and the silicon oxide film (SiO ₂ film) is required. As a technique for performing such a selective etching process of a silicon nitride film, a process using a high temperature (150 ° C. to 160 ° C.) phosphoric acid aqueous solution (H ₃ PO ₄ + H ₂ O) as an etching solution is known. (For example, refer to Patent Document 1). Specifically, as disclosed in Patent Document 1, a plurality of substrates on which a silicon nitride film and a silicon oxide film are formed are immersed in a treatment tank in which a high-temperature phosphoric acid aqueous solution is stored. A selective etching process is performed.

JP 2003-224106 A

  However, when a silicon nitride film is etched using an aqueous phosphoric acid solution, siloxane is generated. “Siloxane” is a general term for a group of organic or inorganic compounds mainly composed of silicon (Si) and oxygen (O). Siloxane produced during the etching process accumulates in the etching solution as foreign matter. As the siloxane accumulates, the etching rate of the silicon nitride film decreases, and when siloxane accumulates in the etchant above a certain concentration, it adheres to the substrate and processing tank, or clogs the filter that circulates the etchant. Cause it.

  This invention is made | formed in view of the said subject, and it aims at providing the substrate processing apparatus which can suppress the excessive raise of the siloxane concentration in the phosphoric acid aqueous solution in a processing tank.

  In order to solve the above-mentioned problems, a first aspect of the present invention provides a substrate processing apparatus for performing a silicon nitride film etching process by immersing a substrate on which a silicon oxide film and a silicon nitride film are formed in a phosphoric acid aqueous solution. An immersion treatment tank for storing an aqueous solution and immersing the substrate in a phosphoric acid aqueous solution to advance an etching process of the silicon nitride film, an aqueous phosphoric acid solution discharged from the immersion treatment tank, an organic solvent, and a TOPO extractant And a liquid tank centrifuge for separating the liquid mixed in the reaction tank into a light liquid containing an organic solvent and a TOPO extractant and an aqueous phosphoric acid solution by centrifugation, And phosphoric acid delivery means for delivering the aqueous phosphoric acid solution separated by the liquid-liquid centrifuge toward the immersion treatment tank.

  The invention of claim 2 is the substrate processing apparatus according to the invention of claim 1, further comprising a filter for removing siloxane remaining in the phosphoric acid aqueous solution separated by the liquid-liquid centrifuge. To do.

  Further, the invention of claim 3 is the substrate processing apparatus according to claim 1 or claim 2, wherein the separation tank for separating siloxane from the light liquid separated by the liquid-liquid centrifuge, And a light liquid delivery means for delivering the light liquid from which the siloxane has been separated in the liquid tank to the reaction tank again.

  According to a fourth aspect of the present invention, in the substrate processing apparatus according to any one of the first to third aspects of the present invention, the phosphoric acid aqueous solution discharged from the immersion bath is cooled to a boiling point or lower of the organic solvent. A cooling means is further provided.

  According to the present invention, the aqueous solution of phosphoric acid discharged from the immersion treatment tank, the organic solvent, and the TOPO extractant are mixed and stirred, and the liquid mixed in the reaction tank is organically separated by centrifugation. Liquid-liquid centrifuge for separating light liquid containing solvent and TOPO extractant and phosphoric acid aqueous solution, and phosphoric acid sending means for sending the phosphoric acid aqueous solution separated by the liquid-liquid centrifuge toward the immersion treatment tank Therefore, the siloxane contained in the phosphoric acid aqueous solution discharged from the immersion treatment tank is extracted by the TOPO extractant and transferred into the dodecane, and the phosphoric acid aqueous solution having a reduced siloxane concentration is centrifuged to be immersed in the immersion treatment tank. Thus, an excessive increase in the siloxane concentration in the aqueous phosphoric acid solution in the immersion treatment tank can be suppressed.

  In particular, according to the second aspect of the present invention, since the filter further removes the siloxane remaining in the phosphoric acid aqueous solution separated by the liquid-liquid centrifuge, the siloxane concentration of the phosphoric acid aqueous solution sent to the immersion treatment tank is adjusted. It can be further reduced.

  In particular, according to the invention of claim 3, a separation tank for separating siloxane from a light liquid separated by a liquid-liquid centrifuge, and a light liquid from which siloxane has been separated by a separation tank are again put into a reaction tank. In addition, the organic solvent and the TOPO extractant can be circulated and reused.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an overall schematic configuration of a substrate processing apparatus according to the present invention. The substrate processing apparatus 1 is a wet etching processing apparatus that selectively etches a silicon nitride film by immersing a substrate W on which a silicon oxide film and a silicon nitride film are formed in a phosphoric acid aqueous solution. The substrate processing apparatus 1 includes an immersion treatment tank 10 that stores an aqueous solution of phosphoric acid and advances an etching process, a circulation line 20 that circulates the aqueous solution of phosphoric acid in the immersion treatment tank 10, and a regeneration line 30 that regenerates the aqueous solution of phosphoric acid. .

  The immersion treatment tank 10 includes an inner tank 11 that stores an aqueous phosphoric acid solution as an etchant, and an outer tank 12 that recovers the overflowed etchant from the upper portion of the inner tank 11. It has a double tank structure. The inner tank 11 is a box-shaped member having a rectangular shape in plan view formed of quartz or a fluororesin material having excellent corrosion resistance against the etching solution. The outer tub 12 is formed of the same material as the inner tub 11 and is provided so as to surround the upper end of the outer periphery of the inner tub 11.

  Further, a lifter 13 for immersing the substrate W in the etching solution stored in the immersion treatment tank 10 is provided. The lifter 13 collectively holds a plurality of (for example, 50) substrates W arranged in parallel with each other in a standing posture (a posture in which the normal line of the substrate main surface is along the horizontal direction) by three holding rods. . The lifter 13 is provided so that it can be moved up and down along the vertical direction by a lifting mechanism (not shown), and a processing position for immersing a plurality of substrates W (lots) to be held in the etching solution in the inner tank 11 (FIG. 1) and the delivery position lifted from the etching solution.

  The circulation line 20 is a piping path for filtering and heating the phosphoric acid aqueous solution discharged from the immersion treatment tank 10 and feeding it back to the immersion treatment tank 10. Specifically, the circulation line 20 is the bottom of the outer tank 12 of the immersion treatment tank 10. And the bottom of the inner tank 11 are connected to each other through a flow path. In the middle of the path of the circulation line 20, a circulation pump 21 and a filter 22 are provided from the upstream side. The circulation pump 21 pumps the aqueous phosphoric acid solution pumped from the outer tank 12 through the circulation line 20 to the inner tank 11. The filter 22 is a filtration filter for removing foreign substances in the phosphoric acid aqueous solution flowing through the circulation line 20.

  The circulation line 20 is provided with a heater 23 downstream of the filter 22. The heater 23 is provided at a position relatively close to the inner tank 11 in the circulation line 20, and reheats the phosphoric acid aqueous solution flowing through the circulation line 20 to a predetermined processing temperature (150 ° C. to 160 ° C.). The immersion treatment tank 10 is also provided with a heater (not shown), and the aqueous phosphoric acid solution stored in the immersion treatment tank 10 is also heated to maintain a predetermined treatment temperature.

  Further, in the path of the circulation line 20, a densitometer 24 is inserted upstream of the circulation pump 21 (side closer to the outer tub 12). The densitometer 24 is a type of densitometer that measures the siloxane concentration in the liquid by measuring the absorbance at a specific wavelength, and the concentration of siloxane contained in the phosphoric acid aqueous solution discharged from the outer tank 12 of the immersion treatment tank 10. Measure the concentration.

  The regeneration line 30 is a piping path for returning a part of the phosphoric acid aqueous solution flowing through the circulation line 20 to the immersion treatment tank 10 through a path different from the circulation line 20. “Regeneration” of the phosphoric acid aqueous solution is to recover the siloxane contained in the phosphoric acid aqueous solution to lower the siloxane concentration. The regeneration line 30 is branched from the downstream of the filter 22 in the circulation line 20 (the side closer to the inner tank 11), and the regenerated phosphoric acid aqueous solution is refluxed to the outer tank 12 of the immersion treatment tank 10. It should be noted that the branch position of the regeneration line 30 can be set to an arbitrary position in the path of the circulation line 20, but if it is downstream of the filter 22 as in this embodiment, foreign matters in the phosphoric acid aqueous solution are removed. It is preferable because the later liquid can be taken out.

  In the middle of the path of the regeneration line 30, a regeneration device 31 that interpolates the siloxane contained in the phosphoric acid aqueous solution and regenerates the phosphoric acid aqueous solution is inserted. The playback device 31 will be further described later. A flow rate adjustment valve 33 is interposed on the downstream side of the regeneration line 30 with respect to the regeneration device 31 (the side closer to the outer tub 12). The flow rate adjustment valve 33 is a valve that adjusts the flow rate of the phosphoric acid aqueous solution flowing through the regeneration line 30.

  The substrate processing apparatus 1 is provided with a control unit 40 that manages the entire apparatus. The configuration of the control unit 40 as hardware is the same as that of a general computer. That is, the control unit 40 stores a CPU that performs various arithmetic processes, a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various information, and control applications and data. It is equipped with a magnetic disk. The control unit 40 controls the operation unit of the substrate processing apparatus 1 such as the circulation pump 21, the heater 23, the lifting / lowering mechanism of the lifter 13, the mechanism in the regeneration device 31, and the flow rate adjustment valve based on the measurement result of the densitometer 24. 33 is controlled.

  FIG. 2 is a diagram illustrating a configuration of the playback device 31 provided in the playback line 30. The regenerator 31 mainly includes a heat exchanger 51, a reaction tank 60, a liquid-liquid centrifuge 70, a liquid separation tank 80, and a filter unit 90. The heat exchanger 51 performs heat exchange between the cooling water supplied from a chiller unit (not shown) and the phosphoric acid aqueous solution flowing through the regeneration line 30 to cool the phosphoric acid aqueous solution. As the heat exchanger 51, various known liquid-liquid heat exchangers such as a plate heat exchanger can be used.

The reaction tank 60 stores the phosphoric acid aqueous solution extracted from the heat exchanger 51 by the pump 52 and the dodecane and TOPO extractant supplied from the separation tank 80 in the tank, and is mixed by the stirrer 61. And stir. Dodecane is a kind of organic solvent, and is a linear alkane represented by the structural formula CH ₃ — (CH ₂ ) ₁₀ —CH ₃ . A TOPO (tri-octyl phosphine oxide) extractant extracts siloxane in an aqueous phosphoric acid solution and transfers it to dodecane, which is an organic solvent.

  The liquid-liquid centrifuge 70 is separated into a phosphoric acid aqueous solution having a relatively large specific gravity and a light liquid containing dodecane and a TOPO extractant having a small specific gravity by applying a centrifugal force by rotation. The liquid-liquid centrifuge 70 sends the separated phosphoric acid aqueous solution to the phosphoric acid relay tank 75 and sends the separated light liquid to the separation tank 80.

  The separation tank 80 separates the phase containing siloxane from the light liquid sent from the liquid-liquid centrifuge 70. The light liquid after separation of the phase containing siloxane is refluxed to the reaction tank 60 by the solvent circulation pump 81. In addition, the separation tank 80 is replenished with dodecane from the dodecane tank 82 by the dodecane pump 83, and is replenished with the TOPO extractant from the TOPO tank 86 by the TOPO pump 87.

  The filter unit 90 removes siloxane remaining in the phosphoric acid aqueous solution fed from the phosphoric acid relay tank 75 by the filter liquid feeding pump 77. The aqueous phosphoric acid solution that has passed through the filter unit 90 flows into the regenerated phosphoric acid tank 95. The regenerated phosphoric acid tank 95 is supplemented with a new phosphoric acid aqueous solution from the phosphoric acid tank 92 by the phosphoric acid pump 93.

  The aqueous phosphoric acid solution stored in the regenerated phosphoric acid tank 95 is sent out to the regeneration line 30 by the regenerated phosphoric acid pump 97. In addition, a phosphoric acid heater 99 is provided in the course of the piping from the regenerative phosphoric acid pump 97 to the regeneration line 30.

  Next, the operation content in the substrate processing apparatus 1 having the above configuration will be described. First, regardless of whether or not the substrate W is immersed in the phosphoric acid aqueous solution stored in the immersion treatment tank 10, the circulation pump 21 constantly pumps the phosphoric acid aqueous solution at a constant flow rate. The aqueous phosphoric acid solution refluxed to the immersion treatment tank 10 by the circulation line 20 is supplied from the bottom of the inner tank 11. As a result, an upflow of the phosphoric acid aqueous solution is generated in the inner tank 11 from the bottom upward. The phosphoric acid aqueous solution supplied from the bottom overflows from the upper end of the inner tank 11 and flows into the outer tank 12. The circulation process in which the phosphoric acid aqueous solution that has flowed into the outer tank 12 is collected by the circulation pump 21 via the circulation line 20 and is fed back to the immersion treatment tank 10 again is continued. In the process of refluxing by the circulation line 20, foreign matters mixed in the phosphoric acid aqueous solution are removed by the filter 22. The refluxed phosphoric acid aqueous solution is reheated to a predetermined processing temperature (160 ° C. in this embodiment) by the heater 23.

  While performing the circulation process of the phosphoric acid aqueous solution by the circulation line 20, the lifter 13 that has received the plurality of substrates W at the delivery position descends to the processing position and is stored in the inner tank 11. The substrate W is immersed therein. As a result, the silicon nitride film is selectively etched out of the silicon oxide film and silicon nitride film formed on the substrate W, and the silicon nitride film is gradually removed. After the etching process for a predetermined time is completed, the lifter 13 rises again to the delivery position and pulls up the substrate W from the etching solution.

  Here, as the etching process of the silicon nitride film proceeds, siloxane accumulates in the phosphoric acid aqueous solution. As described above, when siloxane is excessively accumulated, not only the etching rate of the silicon nitride film is decreased, but also problems such as contamination of the substrate W and the immersion treatment tank 10 and clogging of the filter 22 occur. That's right. For this reason, in this embodiment, the regeneration apparatus 31 is provided in the regeneration line 30 to recover the phosphoric acid aqueous solution by recovering excess siloxane. Hereinafter, the regeneration process of the phosphoric acid aqueous solution in the regeneration apparatus 31 will be described. The basic processing content in the reproducing apparatus 31 is to extract and separate siloxane from an aqueous phosphoric acid solution by a solvent extraction method.

  First, since the phosphoric acid aqueous solution used for the etching process is a relatively high-temperature liquid of about 160 ° C. and cannot be brought into contact with an organic solvent as it is, it is discharged from the immersion treatment tank 10 and is regenerated from the regeneration line 30. The aqueous phosphoric acid solution that has flowed into 31 is cooled by the heat exchanger 51. In the heat exchanger 51, heat exchange is performed between the cooling water supplied from a chiller unit (not shown) and the phosphoric acid aqueous solution flowing through the regeneration line 30, and the phosphoric acid aqueous solution at about 160 ° C is converted to 40 ° C. Cooled to: In addition, the temperature which cools phosphoric acid aqueous solution with the heat exchanger 51 is not limited to 40 degrees C or less, What is necessary is just to be below the boiling point of the organic solvent used for solvent extraction.

  The aqueous phosphoric acid solution cooled in the heat exchanger 51 is sent out to the reaction tank 60 by the extraction pump 52. On the other hand, a mixed solution of dodecane and TOPO extractant is fed from the separation tank 80 to the reaction tank 60 by a solvent circulation pump 81. The aqueous phosphoric acid solution, dodecane and TOPO extractant are mixed in the reaction vessel 60 and stirred by the stirrer 61. By thoroughly mixing and stirring the phosphoric acid aqueous solution, dodecane and the TOPO extractant, the siloxane in the phosphoric acid aqueous solution is extracted by the TOPO extractant and migrates into the dodecane. As a result, the siloxane concentration in the phosphoric acid aqueous solution decreases, and the regeneration treatment of the phosphoric acid aqueous solution is executed.

  After the solvent extraction process in the reaction tank 60, the liquid in the reaction tank 60 (a mixture of phosphoric acid aqueous solution, dodecane and TOPO extractant) is sent out to the liquid-liquid centrifuge 70. The liquid-liquid centrifuge 70 rotates the mixed liquid at a high speed to give a strong acceleration and separates it into a phosphoric acid aqueous solution having a relatively large specific gravity and a light liquid containing dodecane and TOPO extractant having a small specific gravity. The separated phosphoric acid aqueous solution flows into the phosphoric acid relay tank 75, and the light liquid flows into the liquid separation tank 80.

  The aqueous phosphoric acid solution stored in the phosphoric acid relay tank 75 is fed to the filter unit 90 by the filter feed pump 77. The aqueous phosphoric acid solution separated by the liquid-liquid centrifuge 70 and flowing into the phosphoric acid relay tank 75 is one in which most of the siloxane has been removed by solvent extraction in the reaction tank 60, but some siloxane remains. is doing. Such slightly remaining siloxane is also removed by passing through the filter unit 90, and further regeneration treatment of the phosphoric acid aqueous solution is performed.

  The aqueous phosphoric acid solution regenerated through the filter unit 90 flows into the regenerated phosphoric acid tank 95 and is stored. The regenerated phosphoric acid aqueous solution stored in the regenerated phosphoric acid tank 95 contains almost no siloxane. Further, the regenerated phosphoric acid tank 95 is appropriately supplemented with a fresh phosphoric acid aqueous solution in the phosphoric acid tank 92 by a phosphoric acid pump 93.

  The phosphoric acid aqueous solution having a low siloxane concentration stored in the regenerated phosphoric acid tank 95 is sent out to the regeneration line 30 by the regenerated phosphoric acid pump 97. The phosphoric acid aqueous solution delivered by the regenerative phosphoric acid pump 97 is heated to a predetermined processing temperature (160 ° C. in this embodiment) by the phosphoric acid heater 99. Thereby, the regenerated phosphoric acid aqueous solution heated to the treatment temperature is supplied to the regeneration line 30, and the phosphoric acid aqueous solution having a low siloxane concentration flows into the immersion treatment tank 10 from the regeneration line 30. Become. As a result, it is possible to prevent the siloxane concentration in the phosphoric acid aqueous solution in the immersion treatment tank 10 from becoming extremely high. Note that the regenerated phosphoric acid aqueous solution is supplied from the regeneration line 30 to the outer tank 12 of the immersion treatment tank 10 to the outer tank 12 rather than directly supplying the phosphoric acid aqueous solution having a low siloxane concentration to the inner tank 11. This is because the change and distribution of the siloxane concentration in the inner tank 11 is more stable when it is supplied and once passed through the circulation line 20 and then supplied to the inner tank 11.

  On the other hand, a phase containing siloxane is separated from the light liquid flowing into the separation tank 80 from the liquid-liquid centrifuge 70. The organic phase containing siloxane is in the form of a paste, and such a phase is separated from the light liquid in the separation tank 80. The dodecane and the TOPO extractant that have been reduced along with the separation are replenished to the separation tank 80 from the dodecane tank 82 and the TOPO tank 86 by the dodecane pump 83 and the TOPO pump 87, respectively. The mixed solution of dodecane and TOPO extractant from which the phase containing siloxane is separated is fed again from the separation tank 80 to the reaction tank 60 by the solvent circulation pump 81. Thereby, dodecane and TOPO extractant can be reused.

  By performing the regeneration treatment of the phosphoric acid aqueous solution in the regeneration apparatus 31 as described above, the phosphoric acid aqueous solution having a low siloxane concentration can be supplied from the regeneration line 30 to the immersion treatment tank 10, and the inside of the immersion treatment tank 10. An excessive increase in the siloxane concentration in the phosphoric acid aqueous solution can be suppressed.

  Further, the amount of aqueous phosphoric acid solution supplied from the regeneration line 30 is adjusted by the flow rate adjustment valve 33. A concentration meter 24 is provided in the circulation line 20 of the substrate processing apparatus 1, and the control unit 40 controls the flow rate adjustment valve 33 based on the siloxane concentration measurement result of the concentration meter 24. Specifically, when the siloxane concentration in the phosphoric acid aqueous solution discharged from the immersion treatment tank 10 to the circulation line 20 becomes higher than a predetermined value, the control unit 40 controls the flow rate adjustment valve 33 to remove from the regeneration line 30. The flow rate of the phosphoric acid aqueous solution in which the concentration of siloxane flowing in the immersion treatment tank 10 is decreased is increased. On the contrary, when the siloxane concentration in the phosphoric acid aqueous solution discharged from the immersion treatment tank 10 to the circulation line 20 becomes lower than a predetermined value, the control unit 40 controls the flow rate adjustment valve 33 to perform the immersion treatment from the regeneration line 30. The flow rate of the phosphoric acid aqueous solution flowing into the tank 10 is decreased. As a result, the siloxane concentration of the phosphoric acid aqueous solution stored in the immersion treatment tank 10 is maintained at a predetermined value.

  While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention. For example, in the above embodiment, dodecane is used as the organic solvent. However, the present invention is not limited to this, and a solvent of another organic compound may be used.

  Moreover, in the said embodiment, although the phosphoric acid aqueous solution which flowed through the regeneration line 30 was cooled by the heat exchanger 51, the phosphoric acid aqueous solution discharged | emitted from the immersion treatment tank 10 was cooled to below the boiling point of an organic solvent. Other cooling means may be used.

  Further, the configuration of the regenerator 31 is not limited to that shown in FIG. 2. A solvent extraction processing mechanism that mixes and stirs an organic solvent, a TOPO extractant, and an aqueous phosphoric acid solution discharged from the immersion treatment tank 10, and solvent extraction. Any structure that includes a separation mechanism that separates the organic solvent and the TOPO extractant and the phosphoric acid aqueous solution from the subsequent organic solvent and sends the separated phosphoric acid aqueous solution to the immersion treatment tank 10 may be used.

  Moreover, in the said embodiment, the outer tank 12 is not essential, It is the form which connected the piping both ends of the circulation line 20 to the inner tank 11, and circulates the phosphoric acid aqueous solution in the inner tank 11 by the circulation line 20. May be. Further, the lifter 13 is not limited to directly holding the plurality of substrates W, and the lifter 13 may move up and down while holding a carrier containing the plurality of substrates W.

It is a figure which shows the whole schematic structure of the substrate processing apparatus which concerns on this invention. It is a figure which shows the structure of a reproducing | regenerating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 10 Immersion processing tank 11 Inner tank 12 Outer tank 20 Circulation line 21 Circulation pump 22 Filter 24 Densitometer 30 Regeneration line 31 Regeneration apparatus 33 Flow control valve 40 Control part 51 Heat exchanger 60 Reaction tank 70 Liquid-liquid centrifugation Machine 80 Separation tank 81 Solvent circulation pump 90 Filter unit 97 Regenerated phosphoric acid pump 99 Phosphoric acid heater W Substrate

Claims (4)

A substrate processing apparatus for performing an etching process on a silicon nitride film by immersing a substrate on which a silicon oxide film and a silicon nitride film are formed in a phosphoric acid aqueous solution,
An immersion treatment tank for storing a phosphoric acid aqueous solution and immersing the substrate in the phosphoric acid aqueous solution to advance the etching treatment of the silicon nitride film;
A reaction tank in which the aqueous phosphoric acid solution discharged from the immersion treatment tank, an organic solvent, and a TOPO extractant are mixed and stirred;
A liquid-liquid centrifuge for separating the liquid mixed in the reaction tank into a light liquid containing an organic solvent and a TOPO extractant and an aqueous phosphoric acid solution by centrifugation;
Phosphoric acid delivery means for delivering the phosphoric acid aqueous solution separated by the liquid-liquid centrifuge toward the immersion treatment tank;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 1,
The substrate processing apparatus further comprising a filter for removing siloxane remaining in the phosphoric acid aqueous solution separated by the liquid-liquid centrifuge. In the substrate processing apparatus of Claim 1 or Claim 2,
A separation tank for separating siloxane from light liquid separated by the liquid-liquid centrifuge;
A light liquid delivery means for delivering the light liquid from which the siloxane has been separated in the liquid separation tank to the reaction tank again;
A substrate processing apparatus further comprising: In the substrate processing apparatus in any one of Claims 1-3,
The substrate processing apparatus further comprising a cooling means for cooling the phosphoric acid aqueous solution discharged from the immersion treatment tank to a boiling point or less of the organic solvent.

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