System and method for converting waste hydrofluoric acid into cryolite

Abstract

A hydrofluoric acid waste stream from a semiconductor device manufacturing process is collected and converted to cryolite using the disclosed systems and processes. Systems and processes can utilize hydrofluoric acid waste streams from multiple different sources. The systems and processes utilize controlled delivery of reactants such that the cryolite produced has low impurity levels and meets industrial standards. The embodiment of the invention also relates to a system and a method for converting waste hydrofluoric acid into cryolite.

Description

Technical Field

[0001] Embodiments of the present application relate to systems and methods for converting spent hydrofluoric acid into cryolite. Background Art

[0002] In the semiconductor integrated circuit (IC) industry. Technological advances in IC materials and design have produced generations of ICs, each with smaller and more complex circuits than the previous generation. In the course of IC development, functional density (i.e., the number of interconnected devices per chip area) has generally increased, while geometry size (i.e., the smallest component (or line) that can be created using a manufacturing process) has decreased. This shrinking process generally provides benefits by increasing production efficiency and reducing associated costs. Such shrinking has also increased the complexity of IC processing and manufacturing.

[0003] Hydrofluoric acid (HF solution) is used in etching and cleaning steps that are regularly performed in semiconductor device manufacturing. Such hydrofluoric acid poses challenges when it comes to reuse or disposal. For example, the disposal of hydrofluoric acid poses environmental challenges. Reuse of hydrofluoric acid may involve further processing, which may be expensive and yield less than the desired product. Summary of the invention

[0004] Some embodiments of the present application provide a method for converting waste hydrofluoric acid into cryolite, comprising: collecting the waste hydrofluoric acid in a hydrofluoric acid waste collection container; generating a signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container; generating a signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container; transporting hydrofluoric acid from the hydrofluoric acid waste collection container to a reactor; controlling the amount of reactants introduced into the reactor, wherein controlling the amount of reactants introduced into the reactor comprises determining the dosage of the reactants introduced into the reactor based on the generated signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container and the generated signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container; and adjusting the temperature of the contents of the reactor.

[0005] Other embodiments of the present application provide a system for converting waste hydrofluoric acid into cryolite, the system comprising: a hydrofluoric acid collection container, which receives waste hydrofluoric acid from two or more hydrofluoric acid waste sources in a semiconductor device processing facility during operation; a hydrofluoric acid analyzer, which is operably coupled to the hydrofluoric acid collection container, and which generates a signal indicating the concentration of the hydrofluoric acid in the hydrofluoric acid waste collection container during operation; a reactor, which is in fluid communication with the hydrofluoric acid collection container; a reactant container, which is in fluid communication with the reactor; one or more controllers, which control the amount of hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor during operation, and receive a signal indicating the flow rate of the hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor; and control the amount of reactant introduced from the reactant container into the reactor based on the amount of hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor, and receive a signal indicating the flow rate of the reactant introduced into the reactor.

[0006] Still other embodiments of the present application provide a system for converting hydrofluoric acid into cryolite, the system comprising: a hydrofluoric acid collection container, the hydrofluoric acid collection container being operably in communication with at least one quantity determination unit and a hydrofluoric acid analyzer, the quantity determination unit generating a signal indicating the quantity of hydrofluoric acid in the hydrofluoric acid collection container during operation, the hydrofluoric acid analyzer generating a signal indicating the quantity of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container during operation; a reactor in fluid communication with the hydrofluoric acid collection container; a heat transfer unit in thermal communication with the reactor; a reactant container in fluid communication with the reactor; and at least one controller, the at least one controller controlling the quantity of reactants introduced into the reactor from the reactant source based on the signal indicating the quantity of hydrofluoric acid in the hydrofluoric acid collection container and the signal indicating the quantity of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] When read in conjunction with the accompanying drawings, various aspects of the disclosed embodiments can be best understood from the following detailed description. It should be noted that, in accordance with standard practice in the industry, the various components are not drawn to scale. In fact, for clarity of discussion, the size of the various components may be arbitrarily increased or reduced.

[0008] Figure 1 is a schematic piping and instrumentation diagram of a system for converting hydrofluoric acid waste into cryolite according to an embodiment of the present disclosure.

[0009] Figure 2 yes Figure 1 Schematic diagram of the system.

[0010] Figure 2A yes Figure 1 and Figure 2 A schematic diagram of another embodiment of a system.

[0011] Figure 2B yes Figure 1 and Figure 2 A schematic diagram of another embodiment of a system.

[0012] Figure 3 is a schematic diagram of a system for converting hydrofluoric acid waste into cryolite according to an alternative embodiment of the present disclosure.

[0013] Figure 4 is a flow chart of a method for converting waste hydrofluoric acid into cryolite according to an embodiment of the present disclosure.

[0014] Figure 5 is a flow chart of an alternative method for converting spent hydrofluoric acid into cryolite according to an embodiment of the present disclosure.

[0015] Figure 6 is a flow chart of an alternative method for converting spent hydrofluoric acid into cryolite according to an embodiment of the present disclosure.

[0016] Figure 7 is a flow chart of a method for utilizing thermal energy generated by converting spent hydrofluoric acid into cryolite according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0017] The following disclosure provides many different embodiments or examples for realizing the different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the disclosed embodiments. Of course, these are merely examples and are not intended to be limiting. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are directly contacted, and may also include an embodiment in which an additional component may be formed between the first component and the second component so that the first component and the second component may not be in direct contact. In addition, the disclosed embodiments may repeat reference numerals and / or characters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or configurations discussed.

[0018] Additionally, for ease of description, spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used herein to describe the relationship of one element or component to another (or additional) elements or components as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should likewise be interpreted accordingly.

[0019] In the following description, certain specific details are set forth to provide a thorough understanding of the various embodiments of the present disclosure. However, those skilled in the art will appreciate that the embodiments of the present disclosure may be practiced without these specific details. In other examples, known structures associated with electronic components and manufacturing techniques are not described in detail to avoid unnecessarily obscuring the description of the embodiments of the present disclosure.

[0020] Throughout this specification and the claims that follow, the word "comprise" and variations such as "comprises" and "comprising" should be interpreted in an open, inclusive sense to mean "including, but not limited to," unless the context requires otherwise.

[0021] The use of ordinal numbers such as first, second, and third does not necessarily imply a sequential ordering but may merely distinguish between multiple instances of a step or structure.

[0022] Throughout this specification, reference to "one embodiment" or "an embodiment" means that a particular component, structure, or characteristic described in conjunction with the embodiment is included in at least some embodiments. Thus, the phrases "in one embodiment," "in an embodiment," or "in some embodiments" that appear in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, in one or more embodiments, particular components, structures, or characteristics may be combined in any suitable manner.

[0023] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0024] Hydrogen fluoride (HF) is an important chemical in the manufacture of semiconductor devices. Gaseous hydrogen fluoride (also known as 'etching gas') is a compound generated by the combination of hydrogen (H) atoms and fluorine (F). HF is highly reactive and can etch silicon-based solids and polymers used in the manufacture of semiconductor devices. HF has a boiling point of 19.5°C and exists as a gas at room temperature (25°C). However, it is easily liquefied under pressure or at sufficiently cold temperatures. HF is also highly water-soluble. An aqueous solution of HF is called hydrofluoric acid. Hydrofluoric acid is used in the "etching" and "cleaning" steps in the manufacture of semiconductor devices. In the etching step, the role of hydrofluoric acid can be described as "printmaking". Printmaking involves printing a picture in a wooden surface and then using a carving knife to carve out the non-picture parts of the surface. Hydrofluoric acid works like a carving knife, etching away unwanted parts of the wafer. Hydrofluoric acid also has its use in the cleaning process of semiconductor device manufacturing. Even the tiniest impurities can adversely affect the performance of semiconductor devices. For example, impurities can damage circuits, make semiconductor devices unusable, or negatively affect their performance. In the manufacture of semiconductor devices, a cleaning step is necessary to rinse away any remaining foreign matter. Hydrofluoric acid is often used as a cleaning solution. Given the worldwide demand for semiconductor devices, the large number of semiconductor devices manufactured results in a large hydrofluoric acid waste stream from the manufacturing process.

[0025] Cryolite (also known as sodium hexafluoroaluminate) has the chemical formula Na 3 AlF 6 and is a less common mineral. In the Hall-Heroult process, molten cryolite is used as a solvent for the production of alumina. Cryolite is also used in the extraction of aluminum. Cryolite lowers the melting point of alumina from 2000 to 2500°C to 900-1000°C and increases its electrical conductivity, thus making the extraction of aluminum more economical. Cryolite is a glassy, ​​colorless, white-red to gray-black prismatic monoclinic crystal. It has a Mohs hardness of 2.5 to 3 and a specific gravity of about 2.95 to 3.0. Cryolite is translucent to transparent, with a very low refractive index of about 1.34. Cryolite is also used as an insecticide and pesticide, and gives fireworks a yellow color.

[0026] According to an embodiment of the present disclosure, spent hydrofluoric acid from a semiconductor processing facility is treated with a sodium aluminate compound (e.g., sodium aluminate (NaAlO 2 )) to convert into cryolite. The reaction is represented by the chemical equation:

[0027] 6HF+3NaAlO 2 =>Na 3 AlF 6 +3H 2 O+Al 2 O 3

[0028] The above reactions utilize fewer raw materials and can be performed at temperatures that are typically lower than other reactions that can be used to produce cryolite. For example, one such other reaction includes pre-treating hydrofluoric acid waste to produce semi-finished products, such as fluorite or gaseous hydrogen fluoride. These additional pre-treatments can be dangerous and require extremely high temperature reaction environments. Cryolite can also be produced from hydrofluoric acid in a fluidized bed. In order to achieve a controllable hydrofluoric acid outlet concentration using a fluidized bed, continuous reflux is required and the bed can be quite tall, taking up valuable manufacturing floor space. Another disadvantage of producing cryolite in a fluidized bed is that the upper limit of the hydrofluoric acid inlet concentration is low, for example, in the low single digits, and pre-treatment of the hydrofluoric acid is required.

[0029] The disclosed embodiments describe methods and systems for converting waste hydrofluoric acid (e.g., from semiconductor processing facilities) into cryolite. Waste hydrofluoric acid can be obtained from waste hydrofluoric acid generated by the manufacture and processing of semiconductor devices. In some embodiments, the hydrofluoric acid source is a hydrofluoric acid waste source. In other embodiments, the hydrofluoric acid source provides hydrofluoric acid that is not a hydrofluoric acid waste. The conversion of hydrofluoric acid into cryolite reduces the need to dispose of large amounts of hydrofluoric acid and produces useful byproducts. Cryolite can be used as a flux in the aluminum production industry and helps reduce energy consumption by more than 25% in the electrolytic aluminum smelting process. Given that the global production of natural cryolite is scarce and most cryolite is mined, the use of the methods and systems of the disclosed embodiments to produce high-purity cryolite will benefit the aluminum industry and other industries. The methods and systems can be implemented in semiconductor device manufacturing facilities, thereby saving the cost of transporting hydrofluoric acid to an off-site location for further processing or disposal. The systems and methods described herein are also capable of converting hydrofluoric acid into cryolite at a reduced reaction temperature (e.g., in the range of 30 to 90°C). The cryolite produced is of commercial grade purity and can be produced continuously in semiconductor device manufacturing facilities using hydrofluoric acid from multiple different sources (including sources or hydrofluoric acid waste). In some embodiments, the systems and methods described herein utilize waste hydrofluoric acid from two or more different sources, where the waste hydrofluoric acid has different characteristics, such as different concentrations or different HF contents.

[0030] refer to Figure 1 and Figure 2 , an embodiment of a system 100 for converting a hydrofluoric acid waste stream into cryolite is shown. In the remaining description of embodiments according to the present disclosure, hydrofluoric acid is referred to as spent hydrofluoric acid; however, as noted above, embodiments according to the present disclosure are not limited to utilizing hydrofluoric acid waste streams. In other words, embodiments according to the present disclosure include systems and methods for producing cryolite from hydrofluoric acid obtained from a stream that is not a hydrofluoric acid waste stream. Figure 1 is a PID diagram showing various components of system 100 . Figure 2is a schematic diagram of system 100 with further details of the various components and subsystems of system 100. Figure 2 , system 100 includes a plurality of hydrofluoric acid waste sources, represented by hydrofluoric acid waste source 102a and hydrofluoric acid waste source 102b. Figure 2 , two hydrofluoric acid waste sources 102a and 102b are shown. In other embodiments, system 100 includes more than two hydrofluoric acid sources (waste hydrofluoric acid or non-waste hydrofluoric acid), or includes less than two hydrofluoric acid waste sources in other embodiments. Examples of waste hydrofluoric acid sources in semiconductor manufacturing facilities include etching unit operations or cleaning unit operations. Embodiments according to the present disclosure are not limited to these waste hydrofluoric acid sources. According to embodiments of the present disclosure, waste hydrofluoric acid can be provided by a source other than the etching unit operation or the cleaning unit operation in the semiconductor device manufacturing facility. Sources 102a and 102b communicate with the inlet fluid of hydrofluoric acid collection container 103, and hydrofluoric acid collection container 103 is used as a container for receiving and accommodating waste hydrofluoric acid from different sources. As described in more detail below, the outlet of hydrofluoric acid collection container 103 communicates with the inlet fluid of reactor 110.

[0031] Figure 2 The system 100 shown in FIG. 1 also includes a source 104 of a reactant suitable for reacting with the spent hydrofluoric acid to produce cryolite. An example of a reactant suitable for reacting with the hydrofluoric acid to produce cryolite according to an embodiment of the present disclosure is sodium hexafluoroaluminate (NaAlO 2 ). The outlet of the source of reactants 104 is in fluid communication with the inlet of the reactant container 106. Figure 2 In the embodiment of the present invention, the source 104 and the reactant container 106 are shown as different containers. In other embodiments, the reactant source 104 and the reactant container 106 can be a single container. As described in more detail below, the outlet of the reactant container 106 is in fluid communication with the inlet of the reactor 110.

[0032] The hydrofluoric acid collection container 103 is associated with a device P1 for determining the amount of hydrofluoric acid contained in the hydrofluoric acid collection container 103. The amount of hydrofluoric acid contained in the hydrofluoric acid collection container 103 can be expressed in mass units or volume units. For example, in some embodiments, the device P1 is configured to determine the mass of the hydrofluoric acid contained in the hydrofluoric acid collection container 103. In other embodiments, the device P1 is configured to determine the volume of the hydrofluoric acid contained in the hydrofluoric acid collection container 103. An example of a device capable of determining the mass of the hydrofluoric acid contained in the hydrofluoric acid collection container 103 is a load sensor. The load sensor converts a force such as tension, compression, pressure or torque into an electrical signal representing the mass of the container placed on the load sensor. Embodiments according to the present disclosure are not limited to using a load sensor for the purpose of determining the mass of the hydrofluoric acid in the hydrofluoric acid collection container 103. For example, other devices for determining the mass of the hydrofluoric acid in the hydrofluoric acid collection container 103 can be utilized. The load sensor may also be used to determine the volume of hydrofluoric acid in the hydrofluoric acid collection container 103 by utilizing the mass detected by the load sensor and converting the mass to a volume utilizing the known density of the hydrofluoric acid contained in the collection container 103. Other devices may be used to determine the volume of hydrofluoric acid in the hydrofluoric acid collection container 103. For example, a continuous flow level transmitter, a differential pressure transmitter, a radar level transmitter, a radio frequency transmitter, or an ultrasonic level transmitter may be utilized to determine the volume of hydrofluoric acid in the hydrofluoric acid collection container 103. In some embodiments, the hydrofluoric acid collection container 103 is associated with a single load sensor, and in other embodiments, multiple load sensors are associated with the hydrofluoric acid collection container 103 for redundancy and / or averaging.

[0033] In some embodiments, a load sensor P2 (for determining the mass or volume of the reactant) or device for determining the volume of the reactant in the reactant container 106 is associated with the reactant container 106 and is configured to determine the amount of the reactant in the container 106 using techniques similar to those described above for determining the mass or volume of the hydrofluoric acid contained in the hydrofluoric acid collection container 103.

[0034] System 100 includes a chemical analyzer F1, for example, a chemical analyzer capable of determining the amount of hydrogen fluoride in hydrofluoric acid, for example, the concentration of hydrogen fluoride in hydrofluoric acid. Figure 1 In the embodiment, the inlet of the chemical analyzer F1 is in fluid communication with the hydrofluoric acid collection container 103 via the conduit 112. The outlet of the chemical analyzer F1 is in fluid communication with the reactor 110 via the conduit 114, as described in more detail below. In other embodiments, the chemical analyzer F1 can be integrated with the hydrofluoric acid collection container 103, such as Figure 2, thereby eliminating the need for conduit 112. Chemical analyzer F1 is capable of determining the amount of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid collection container 103. For example, chemical analyzer F1 can determine the concentration of hydrogen fluoride in the hydrofluoric acid (e.g., wt%, molar concentration, mass molar concentration, or ppm). In some embodiments, chemical analyzer F1 has a sensitivity that allows it to measure a hydrogen fluoride concentration between about 10 and 50 weight percent in the hydrofluoric acid. In other embodiments, chemical analyzer F1 is capable of determining the concentration of hydrofluoric acid in the solution in a range between 15 and 45 weight percent. Chemical analyzer F1 is capable of determining the aforementioned hydrofluoric acid concentration in the solution at a temperature at which the hydrofluoric acid is contained in the hydrofluoric acid waste collection container 103. Chemical analyzer F1 is made of a material that is resistant to hydrofluoric acid degradation at the concentration to be analyzed in analyzer F1. In some embodiments, a second chemical analyzer F2 is provided to analyze the concentration (e.g., wt%, molar concentration, mass molar concentration, or ppm) of the reactants contained in the reactant container 106 and ultimately introduced into the reactor 110. In Figure 1 In the embodiment shown in FIG. 1 , the outlet of the second chemical analyzer F2 is in fluid communication with the reactor 110 via a conduit 116. The inlet of the second chemical analyzer F2 is in fluid communication with the reactant source ( Figure 1 In some embodiments, as shown in FIG. Figure 2 As shown in , the second analyzer F2 can be integrated with the reactant container 106, which eliminates the need for the pipe 118. The hydrofluoric acid waste collection container 103, the reactant container 106, the hydrofluoric acid collection container load sensor P1, the reactant container load sensor P2 and the hydrofluoric acid collection container chemical analyzer F1 constitute the quantitative analysis subsystem 138. In other embodiments, the quantitative analysis subsystem 138 also includes a reactant container chemical analyzer F2.

[0035] The outlet of the hydrofluoric acid waste collection container 103 is in fluid communication with the inlet of the reactor 110. The amount of hydrofluoric acid flowing from the hydrofluoric acid waste collection container 103 to the reactor 110 can be controlled by a flow meter M1 located between the hydrofluoric acid waste collection container 103 and the reactor 110. The flow meter M1 is communicatively coupled to the controller 108. The outlet of the reactant container 106 is in fluid communication with the inlet of the reactor 110. The flow of the reactants from the reactant container 106 to the reactor 110 can be controlled by a flow meter M2 located between the reactant container 106 and the reactor 110. The flow meter M2 is communicatively coupled to the controller 108. Figure 1 and Figure 2 In the embodiment shown in , a single controller 108 is shown. Embodiments according to the present disclosure are not limited to a single controller 108. In other embodiments, multiple controllers may be utilized.

[0036] Reactor 110 is a container in which spent hydrofluoric acid and reactants are combined and allowed to react and form cryolite. Reactor 110 is formed of a material that is resistant to degradation by the hydrofluoric acid and reactants introduced therein, as well as resistant to degradation by the cryolite formed. Figure 1 and Figure 2 In the embodiment shown in FIG. , heat energy can be transmitted via Figure 1 The combination of the heating coil 120, the coolant tank 122, and the heat transfer unit 124 in the reactor 110 is removed from or introduced into the reactor 110. The reactor 110 is in thermal communication with the heating coil 120 so that heat energy can be transferred from the reactor 110 to the fluid contained in the heating coil 120, or heat energy from the fluid contained in the heating coil 120 can be transferred to the reactor 110. The heating coil 120 is sized (length, diameter, surface area in contact with the reactor, etc.) so that it can remove sufficient heat energy from the reactor to adjust and / or maintain the temperature of the contents of the reactor at a temperature that promotes crystal formation of cryolite and stabilizes the purity of the cryolite formed. For example, the heating coil is sized to remove sufficient heat energy from the contents of the reactor 110 so that the temperature of the contents of the reactor is controlled between about 20-100° C. during the active reaction of the hydrofluoric acid and the reactants. In other embodiments, the heating coil 120 is sized so that the temperature of the contents of the reactor is controlled between about 40 and 100° C. or between 40 and 90° C. In other embodiments, the heating coil 120 is sized so that the temperature of the contents of the reactor can be controlled and maintained between 40 and 80° C. or between 50 and 80° C. In some embodiments, the fluid in the heating coil 120 is delivered to a coolant container 122 that collects the fluid. The coolant container 122 is in fluid communication with a heat transfer unit 124, where heat energy can be removed from the coolant or heat energy can be introduced into the coolant. In an optional embodiment, the coolant container 122 can be omitted, and the coolant flows directly from the heating coil 120 to the heat transfer unit 124. Examples of the heat transfer unit 124 include a heat exchanger or a similar device. In some embodiments, the heat transfer unit 124 is configured to convert the heat energy received from the fluid into an optional energy form different from the heat energy, for example, electrical energy. The electrical energy can then be delivered to an optional energy load 126. Examples of such types of heat transfer units include boilers or evaporators that can convert liquids into steam. The steam can then be used to drive an electrical generator, such as a turbine. Embodiments according to the present disclosure are not limited to boilers or evaporators as types of heat transfer units. For example, other systems or devices that can generate electrical energy from the heat energy of a coolant are useful according to embodiments of the present disclosure. Examples of coolants useful according to embodiments of the present disclosure include low boiling point compounds such as isopropyl alcohol, C 3 H 5 , CH 2 Cl2 and C 3 H 6 O. Figure 1 and Figure 2 In an embodiment, the reactor 110 also includes a sensor T. In one embodiment, the sensor T is configured to sense the temperature of the reactor 110 or the contents of the reactor 110. In other embodiments, the sensor T is a different type of sensor that can be used to monitor or control the formation of cryolite in the reactor 110, such as a pH sensor, a chemical analyzer for determining the concentration of hydrofluoric acid or reactants in the reactor 110, a sensor for detecting a fluid level within the reactor 110, or any other sensor capable of detecting a characteristic of the reactor 110 or the contents of the reactor 110.

[0037] The outlet of reactor 110 is in fluid communication with the cryolite collection and isolation subsystem. Figure 2 As shown in , the cryolite collection and isolation subsystem includes a cryolite collection tank 130 in fluid communication with the outlet of the reactor 110. Cryolite and water are received in the cryolite collection tank 130. In the cryolite isolation unit operation 132, cryolite crystals are separated from water. The separated water is removed from the cryolite isolation unit operation 132 via a drain 136. According to an embodiment of the present disclosure, the separated water has a hydrofluoric acid content of less than 10,000 ppm, and in some embodiments, less than 5,000 ppm. The resulting isolated cryolite is transferred from the cryolite isolation unit operation 132 to a cryolite storage / transport stage 134. The reactor 110, the coolant tank 122, and the temperature sensor T constitute a reaction and cooling subsystem 140.

[0038] Figure 1 and Figure 2 The system 100 includes a controller 108 for controlling the production of cryolite according to the method described in more detail below. The controller 108 is connected to the load sensor P1, the load sensor P2, the chemical analyzer F1, the chemical analyzer F2, the flow meter M1, the flow meter M2 and the sensor T (for clarity purposes, Figure 21, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 47, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 61, 62, 59, 63, 58, 59, 64, 59, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,

[0039] The embodiments of the system 100 described above are used to convert hydrofluoric acid from a waste stream or hydrofluoric acid from a non-waste stream produced in a semiconductor manufacturing facility into cryolite using embodiments of the methods described below. Figure 4, illustrating operations of an embodiment of a method 400 for producing cryolite according to an embodiment of the present disclosure. The method 400 includes an operation 402 of collecting hydrofluoric acid from one or more waste streams from a semiconductor manufacturing facility or multiple semiconductor manufacturing facilities. Operation 402 can be performed by collecting hydrofluoric acid waste from hydrofluoric acid waste sources 102a and 102b and collecting such waste in a hydrofluoric acid waste collection container 103. In operation 404, a signal is generated indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container 103. Such a signal can be generated by a load sensor P1 and can be, for example, a signal representing the mass of hydrofluoric acid in the hydrofluoric acid waste collection container 103 or the volume of hydrofluoric acid in the hydrofluoric acid waste collection container 103. In operation 406, a signal is generated indicating the concentration of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid waste collection container 103. The signal indicating the concentration of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid waste collection container can be generated by a chemical analyzer F1. In operation 408, hydrofluoric acid from the hydrofluoric acid waste collection container is delivered to the reactor 110. According to some embodiments, the concentration of hydrogen fluoride in the hydrofluoric acid delivered to the reactor 110 is between about 5 and 40 weight percent. In other embodiments, the concentration of hydrogen fluoride in the hydrofluoric acid delivered to the reactor 110 is between about 8 and 30 weight percent. The flow rate of the hydrofluoric acid delivered to the reactor 110 can be controlled by a flow meter M1. Based on the length of time that the hydrofluoric acid flow rate is maintained in operation 409 and the known concentration of hydrofluoric acid, a signal representing the amount of hydrofluoric acid or hydrogen fluoride delivered to the reactor (and the reaction equivalent of hydrogen fluoride delivered to the reaction vessel 110) can be generated. In operation 410, the amount of reactants introduced into the reactor 110 is controlled. As described in more detail below, the amount of reactants introduced into the reactor 110 can be controlled by a flow meter M2 and based on the determined equivalent of hydrogen fluoride delivered to the reactor 110. In operation 412, hydrogen fluoride of hydrofluoric acid and reactants react in reactor 110 to produce a cryolite-containing solution. In operation 414, cryolite-containing solution is recovered from reactor 110 using, for example, cryolite collection tank 130. Cryolite is then recovered from the cryolite-containing solution in operation 416 using, for example, cryolite isolation unit operation 132.

[0040] According to this embodiment of the method 400, the controller 108 controls the flow rate and the amount of reactants to the reactor 110 by controlling the flow meter M2 to allow the desired amount of reactants to flow from the reactant container 106 into the reactor 110 and monitoring the amount of reactants flowing into the reactor 110 using the flow meter M2. According to an embodiment of the present disclosure, the controller 108 receives a signal from the load sensor P1 indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container 103. As noted above, the load sensor P1 generates a signal representing the mass of hydrofluoric acid in the hydrofluoric acid waste collection container 103 or the volume of hydrofluoric acid in the hydrofluoric acid waste collection container 103. In one embodiment, when the load sensor generates a signal indicating the mass (e.g., grams or kilograms) of hydrofluoric acid (i.e., hydrogen fluoride in solution) in the hydrofluoric acid waste collection container 103, the chemical analyzer F1 generates a signal indicating the concentration of the hydrofluoric acid, for example, grams of hydrogen fluoride contained in the hydrofluoric acid waste collection container 103 / grams of hydrofluoric acid solution. The controller 108 is programmed to determine the reaction equivalent of the hydrogen fluoride in the hydrofluoric acid waste collection container 103 using the signal indicating the mass of the hydrofluoric acid in the hydrofluoric acid waste collection container 103 and the signal indicating the concentration of the hydrofluoric acid in the hydrofluoric acid waste collection container 103. The reaction equivalent of the hydrogen fluoride introduced into the reactor 110 is determined based on the mass or volume of the hydrofluoric acid delivered to the reactor 110 by the flow meter M1. The volume of the hydrofluoric acid delivered to the reactor 110 may be determined by the flow meter M1. The mass of the hydrofluoric acid delivered to the reactor 110 may be determined by calculating the difference between the mass of the hydrofluoric acid in the hydrofluoric acid waste collection container 103 before the hydrofluoric acid is removed from the hydrofluoric acid waste collection container 103 and introduced into the reactor 110 and the mass of the hydrofluoric acid in the hydrofluoric acid waste collection container 103 after the flow of the hydrofluoric acid from the hydrofluoric acid waste collection container 103 to the reactor 110 is stopped. The determined reaction equivalent of hydrogen fluoride introduced into the reactor 110 is then used to determine the dosage of the reactants introduced into the reactor to achieve the desired level of conversion of hydrogen fluoride to cryolite. The determined dosage of the reactants for introduction into the reactor may be determined by the controller 108. For example, in some embodiments, the dosage of the reactants is guided by the following equation:

[0041] Reactant dosage (mass) = DF dosage factor (DF) x concentration of hydrofluoric acid added to the reactor (wt%) x mass of hydrofluoric acid added to the reactor;

[0042] Wherein, when the concentration of reactant (in wt%) is between about 15-45wt%, DF is between about 0.01-0.95 in some embodiments, and between 0.1-0.70 in other embodiments. In other embodiments, when the concentration of reactant (in wt%) is between about 15-45wt%, DF is in the range of about 0.1-0.50, 0.15-0.50 or 0.25-0.50. Still in other embodiments, DF is in the range of 0.25-0.35. According to the embodiments of the present disclosure, it is not limited to the aforementioned range of DF. For example, if the concentration of reactant is greater than 15-45 weight percent, DF can be lower than the scope described above. If the concentration of reactant is less than 15-45 weight percent, DF can be higher than the scope described above.

[0043] The reactant dosage can also be determined by the following equation:

[0044] Reactant dosage (moles) = DF dosage factor (DF) x concentration of hydrofluoric acid added to the reactor (molar concentration) x volume of hydrofluoric acid added to the reactor.

[0045] According to the aforementioned embodiment, after the reactant dosage is determined by the controller 108, the controller 108 causes the flow meter M2 to allow the desired reactant dosage to flow from the reactant container 106 into the reactor 110. The desired reactant dosage is distributed to the reactor by knowing the reactant concentration in the reactant container 106 and controlling the mass or volume flow of the reactant passing through the flow meter M2, so as to provide a determined reactant dosage based on the reaction equivalent of the hydrogen fluoride in the reactor 110. The concentration of the reactant can be predetermined, that is, provided by the reactant supplier, or can be determined using a chemical analyzer F2. The reaction equivalent of the reactant contained in the reactant container 106 can be determined based on the reactant concentration in the reactant container 106 and using a load sensor P2 to determine the mass or volume of the reactant in the reactant container 106.

[0046] The reaction between hydrogen fluoride and the reactants is exothermic. The reaction temperature promotes the dissolution of cryolite into the solution in the reactor 110. In some embodiments, the controller 108 controls the flow rate (e.g., mass or volume per unit time) of the hydrofluoric acid and reactants flowing into the reactor 110 so that the heat energy generated by the exothermic reaction between hydrogen fluoride and the reactants keeps the temperature of the solution in the reactor 110 high enough so that the cryolite formed remains in the solution and the contents of the reactor are not subjected to thermal shock that may adversely affect the reaction efficiency in the reactor 110.

[0047] refer to Figure 5 , showing an optional embodiment of the method for producing cryolite according to an embodiment of the present disclosure. Figure 5Examples and Figure 4 The difference of the embodiment is that Figure 5 The embodiment of does not utilize a flow meter to determine the amount of hydrofluoric acid or the reaction equivalent of hydrogen fluoride or the amount of reactants introduced into the reactor 110. Figure 5 In the embodiment of the present invention, the change in mass or volume of the hydrofluoric acid in the hydrofluoric acid waste collection container 103 and the change in mass or volume of the reactant in the reactant container 106 are used to determine the amount of hydrofluoric acid and the amount of the reactant introduced into the reactor 110. Figure 5In an embodiment of the method 500 of the present invention, the method 500 includes an operation 502 of collecting hydrofluoric acid from one or more waste streams in a semiconductor manufacturing facility or multiple semiconductor manufacturing facilities. Operation 502 can be performed by collecting hydrofluoric acid waste from hydrofluoric acid waste sources 102a and 102b and collecting such waste in a hydrofluoric acid waste collection container 103. In operation 504, a signal is generated indicating the amount of hydrofluoric acid contained in the hydrofluoric acid waste collection container 103. Such a signal can be generated by a load sensor P1 and can be, for example, a signal representing the mass of hydrofluoric acid in the hydrofluoric acid waste collection container 103 or the volume of hydrofluoric acid in the hydrofluoric acid waste collection container 103. Then, in operation 506, a signal is generated indicating the concentration of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid waste collection container 103. According to the above discussion, the signal indicating the concentration of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid waste collection container can be generated by a chemical analyzer F1. The method 500 continues with operation 507, in which a signal indicating the amount of reactant in the reactant container 106 is generated. According to the above discussion, determining the amount of reactants in the reactant container 106 and generating a signal indicating the amount of reactants in the reactant container 106 can be performed using the load sensor P2. In operation 508, hydrofluoric acid from the hydrofluoric acid waste collection container is delivered to the reactor 110. Operation 510 includes generating a signal indicating the amount of hydrofluoric acid remaining in the hydrofluoric acid waste collection container 103. Generating a signal indicating the amount of hydrofluoric acid remaining in the hydrofluoric acid waste collection container 103 can be performed using the load sensor P1. In operation 511, the reaction equivalent of hydrogen fluoride delivered to the reactor 110 is determined. The reaction equivalent of hydrogen fluoride delivered to the reactor 110 is determined by calculating the difference between the amount of hydrofluoric acid in the hydrofluoric acid waste collection container 103 determined in operation 504 and the amount of hydrofluoric acid in the hydrofluoric acid waste collection container 103 determined in operation 510 to reveal the amount of hydrofluoric acid introduced into the reactor 110. Then, the reaction equivalent of hydrogen fluoride delivered to reactor 110 is determined using the known amount of hydrofluoric acid introduced into reactor 110 and the hydrogen fluoride concentration of the hydrofluoric acid introduced into reactor 110. The amount of reactant introduced into reactor 110 is determined in operation 512. Determining the amount of reactant introduced into reactor 110 can be performed using the known reaction equivalent of hydrogen fluoride introduced into reactor 110 as determined in operation 511 and the dosage equation described above. In operation 514, reactant is delivered to reactor 110 from reactant container 106. In operation 516, a signal indicating the amount of reactant removed from reactant container 106 is generated. The signal indicating the amount of reactant removed from reactant container 106 is generated by subtracting the amount of reactant present in reactant container 106 as determined by load sensor P1 when performing operation 516 from the amount of reactant in reactant container 106 determined in operation 507.The amount of reactant removed from the reactant container 106 indicates the amount of reactant introduced into the reactor 110. The reactant is introduced into the reactor 110 until it is determined that the amount of reactant delivered to the reactor 110 corresponds to the amount of reactant determined in operation 512. For example, the reactant is introduced into the reactor 110 until it is determined that a determined reaction equivalent of the reactant has been introduced into the reactor 110. Once it is determined that the amount of reactant delivered to the reactor 110 corresponds to the amount of reactant determined in operation 512, delivery of the reactant to the reactor 110 is terminated in operation 518.

[0048] Figure 3 An alternative system 300 for producing cryolite from a hydrofluoric acid waste stream in a semiconductor manufacturing facility is shown in accordance with an embodiment of the present disclosure. Figure 3 An embodiment similar to Figure 1 and Figure 2 The embodiment of the present invention is different in that the load sensors P1 and P2 and the chemical analyzer F2 are omitted. Figure 3 The embodiments include many Figure 1 and Figure 2 Same components. Figure 1 and Figure 2 The components are exactly the same Figure 3 The components are identified by the same reference numerals and Figure 1 and Figure 2 The description of those components also applies to Figure 3 The same components as below. Figure 6 The method 600 is described in more detail according to Figure 3 In an embodiment, a chemical analyzer F1 and flow meters M1 and M2 are used to generate a signal indicating the reaction equivalent of hydrofluoric acid introduced into the reactor 110, and the delivery of reactants to the reactor 110 is controlled without using load sensors P1 and P2.

[0049] according to Figure 6 The embodiment of the method 600 begins with operation 602 of collecting a waste stream or multiple waste streams of hydrofluoric acid in a hydrofluoric acid waste collection container (e.g., hydrofluoric acid waste collection container 103). The description above regarding operation 502 is also applicable to operation 602. The method 600 continues with operation 604, where a signal indicating the molar concentration (mol / L) of hydrofluoric acid in the hydrofluoric acid waste collection container 103 is generated, for example, by a chemical analyzer F1. In operation 606, the hydrofluoric acid is transported from the hydrofluoric acid waste collection container 103 to the reactor 110. The description above regarding operation 502 is also applicable to operation 602. Figure 4The description of operation 408 in is also applicable to this operation 606. In operation 608, a signal indicating the reaction equivalent of hydrogen fluoride delivered to the reactor 110 is generated. The signal indicating the reaction equivalent of hydrogen fluoride delivered to the reactor 110 is generated by multiplying the molar concentration of hydrofluoric acid in the waste hydrofluoric acid collection container 103 by the volume of hydrofluoric acid delivered to the reactor 110 (as determined by the M1 flow meter). Using the known reaction equivalent of hydrogen fluoride delivered to the reactor 110, the reactant dosage for delivery to the reactor 110 can be determined using the equation described above and the dosage factor (DF) in operation 610. Method 600 continues with operation 612 involving the delivery of reactants to the reactor 110. The delivery of reactants to the reactor 110 continues until the determined amount of reactants has been delivered to the reactor 110. After the determined amount of reactants has been delivered to the reactor 110, method 600 terminates in operation 614.

[0050] Figure 2A and Figure 7 Alternative embodiments of systems and methods for converting spent hydrofluoric acid to cryolite in accordance with embodiments of the present disclosure are shown. Figure 2A An optional system 250 is shown, which is Figure 1 and Figure 2 The system 250 is a modification of the system 100. The system 250 differs from the system 100 in that the cooling medium circulating in the coil 120 is directly delivered to the heat transfer / conversion unit 124, rather than being Figure 1 and Figure 2 Components of system 250 that are identical to components of system 100 are identified by the same reference numerals used to describe system 100.

[0051] System 250 and system 100 may be used to implement Figure 7The method 700 includes an operation 702 of collecting hydrofluoric acid from one or more waste streams in a semiconductor manufacturing facility or multiple semiconductor manufacturing facilities. Operation 702 can be performed by collecting hydrofluoric acid waste from hydrofluoric acid waste sources 102a and 102b and collecting such waste in a hydrofluoric acid waste collection container 103. In operation 704, a signal is generated indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container 103. Such a signal can be generated by a load sensor P1 and can be, for example, a signal representing the mass of hydrofluoric acid in the hydrofluoric acid waste collection container 103 or the volume of hydrofluoric acid in the hydrofluoric acid waste collection container 103. Then, in operation 706, a signal is generated indicating the concentration of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid waste collection container 103. The signal indicating the concentration of hydrogen fluoride in the hydrofluoric acid contained in the hydrofluoric acid waste collection container 103 can be generated by a chemical analyzer F1. In operation 708, the hydrofluoric acid from the hydrofluoric acid waste collection container 103 is delivered to the reactor 110. The flow rate of hydrofluoric acid delivered to reactor 110 can be monitored and controlled by flow meter M1. In operation 709, a signal representing the amount of hydrofluoric acid delivered to the reactor (and thereby the reaction equivalent of hydrogen fluoride delivered to reaction vessel 110) can be generated based on the flow rate of the hydrofluoric acid and the length of time the flow rate is maintained. In operation 710, the amount of reactants introduced into reactor 110 is controlled. The amount of reactants introduced into reactor 110 can be monitored and controlled by flow meter M2 based on a determined equivalent of hydrogen fluoride delivered to reactor 110. In operation 712, hydrogen fluoride and reactants react in reactor 110 to produce a cryolite-containing solution. In method 700, in operation 714, by Figure 1 The coil 120 in the reactor 110 removes thermal energy from the reactor 110. The thermal energy removed from the reactor 110 by the coil 120 in operation 714 is converted into an alternative energy form different from thermal energy in operation 716. This conversion of thermal energy into an alternative energy form different from thermal energy can be performed by a thermal energy conversion unit 124 ( Figure 2A ) and to the optional energy load 126 ( Figure 2A The optional energy form of the medium is used for execution.

[0052] Figure 2B A system 150 according to another embodiment of the present disclosure is shown. The system 150 is similar to the system 150 of the above reference Figure 2 The components of system 150 that are identical to the components of system 100 are identical to the components of system 150. Figure 2The reference numerals identical with the reference numerals used in are identified. The difference between system 150 and system 100 is that system 150 includes a waste hydrofluoric acid mixing device 152 between waste hydrofluoric acid sources 102a, 102b, 102c and 102d. The inlet side of the waste hydrofluoric acid mixing device 152 communicates with each fluid of a plurality of different hydrofluoric acid waste sources 102a, 102b, 102c and 102d. According to an embodiment of the present disclosure, these plurality of different hydrofluoric acid waste sources provide hydrofluoric acid with different concentrations. The outlet side of the waste hydrofluoric acid mixing device 152 communicates with the hydrofluoric acid waste collection container 103 fluids. In operation, the waste hydrofluoric acid mixing device 152 receives waste hydrofluoric acid from two or more of the hydrofluoric acid waste sources 102a, 102b, 102c and 102d, and two or more hydrofluoric acid waste streams are mixed. The flow from the hydrofluoric acid waste sources 102a, 102b, 102c and 102d to the hydrofluoric acid waste mixing device 152 is controlled by a valve or flow meter (not shown). Providing the hydrofluoric acid mixing device 152 between the spent hydrofluoric acid sources 102a, 102b, 102c and 102d and the waste collection container 103 allows the operator to adjust the concentration of the hydrofluoric acid delivered to the hydrofluoric acid waste collection container 103. By mixing the spent hydrofluoric acid streams with different concentrations in the spent hydrofluoric acid mixing device 152, a hydrofluoric acid mixture with a desired hydrogen fluoride concentration can be produced for delivery to the hydrofluoric acid waste collection container 103, and ultimately delivered to the reactor 110.

[0053] The cryolite produced according to embodiments of the present disclosure exhibits sufficiently low impurity content so that it meets commercial cryolite purity standards, thereby making the produced cryolite suitable for industrial applications. In some embodiments, the cryolite produced according to embodiments of the present disclosure exhibits a sodium content of less than about 32 weight percent.

[0054] In one embodiment, the disclosed embodiments relate to a method for converting waste hydrofluoric acid into cryolite. Such a method includes: collecting waste hydrofluoric acid in a hydrofluoric acid waste collection container; and generating a signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container. A signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container is also generated. The hydrofluoric acid from the hydrofluoric acid waste collection container is delivered to a reactor. The amount of reactants is introduced into the reactor, and the amount of reactants introduced into the reactor is controlled by determining the dosage of the reactants introduced into the reactor based on the generated signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container and the generated signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container. According to some embodiments, the temperature of the contents of the reactor is adjusted to control the conversion of hydrofluoric acid into cryolite.

[0055] In another embodiment, the disclosed embodiments relate to a system for converting waste hydrofluoric acid into cryolite. Such a system includes: a hydrofluoric acid collection container, which receives waste hydrofluoric acid from two or more waste hydrofluoric acid sources in a semiconductor device processing facility during operation; a hydrofluoric acid analyzer, which is operably coupled to the hydrofluoric acid collection container, and the hydrofluoric acid analyzer generates a signal indicating the concentration of hydrofluoric acid in the hydrofluoric acid waste collection container during operation. The reactor is in fluid communication with the hydrofluoric acid collection container, and the reactant container is in fluid communication with the reactor. The system includes one or more controllers, which control the amount of hydrofluoric acid introduced into the reactor from the hydrofluoric acid collection container during operation, and receive a signal indicating the flow rate of hydrofluoric acid introduced into the reactor from the hydrofluoric acid collection container. The one or more controllers also control the amount of reactants introduced into the reactor from the reactant container based on the amount of hydrofluoric acid introduced into the reactor from the hydrofluoric acid collection container, and receive a signal indicating the flow rate of the reactants introduced into the reactor.

[0056] Another embodiment of the present disclosure relates to a system for producing cryolite from hydrofluoric acid, and includes a hydrofluoric acid collection container and a reactor. The hydrofluoric acid collection container is operably in communication with at least one quantity determination unit, which generates a signal indicating the amount of hydrofluoric acid in the hydrofluoric acid collection container during operation. The hydrofluoric acid collection container is also operably in communication with a hydrofluoric acid analyzer, which generates a signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container during operation. The system also includes: a reactor, which is in fluid communication with the hydrofluoric acid collection container; a heat transfer unit, which is in thermal communication with the reactor; a reactant container, which is in fluid communication with the reactor; and at least one controller, which controls the amount of reactants introduced into the reactor from the reactant source based on the signal indicating the amount of hydrofluoric acid in the hydrofluoric acid collection container and the signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container during operation.

[0057] Some embodiments of the present application provide a method for converting waste hydrofluoric acid into cryolite, comprising: collecting the waste hydrofluoric acid in a hydrofluoric acid waste collection container; generating a signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container; generating a signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container; transporting hydrofluoric acid from the hydrofluoric acid waste collection container to a reactor; controlling the amount of reactants introduced into the reactor, wherein controlling the amount of reactants introduced into the reactor comprises determining the dosage of the reactants introduced into the reactor based on the generated signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container and the generated signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container; and adjusting the temperature of the contents of the reactor.

[0058] In some embodiments, collecting the waste hydrofluoric acid includes collecting hydrofluoric acid waste from two or more hydrofluoric acid waste sources in a semiconductor device processing facility.

[0059] In some embodiments, the hydrofluoric acid waste from the two or more sources comprises different amounts of hydrogen fluoride.

[0060] In some embodiments, the method further includes reacting the hydrofluoric acid in the reactor with the reactants in the reactor to form cryolite.

[0061] In some embodiments, the method further comprises removing heat energy from the reactor generated by forming cryolite in the reactor, and delivering the removed heat energy to a thermal energy conversion unit.

[0062] In some embodiments, the method further comprises receiving the thermal energy from the reactor at the thermal energy conversion unit and utilizing the received thermal energy to generate an alternative energy form different from thermal energy.

[0063] In some embodiments, the selectable energy form is electrical energy.

[0064] In some embodiments, the amount of the hydrofluoric acid in the hydrofluoric acid waste collection container is the mass of the hydrofluoric acid solution in the hydrofluoric acid waste collection container, and the amount of the hydrogen fluoride in the hydrofluoric acid is the weight percentage of the hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container.

[0065] In some embodiments, the amount of the hydrofluoric acid in the hydrofluoric acid waste collection container is the volume of the hydrofluoric acid solution in the hydrofluoric acid waste collection container, and the amount of the hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container is the molar concentration of the hydrofluoric acid.

[0066] Still other embodiments of the present application provide a system for converting waste hydrofluoric acid into cryolite, the system comprising: a hydrofluoric acid collection container, the hydrofluoric acid collection container receiving waste hydrofluoric acid from two or more hydrofluoric acid waste sources in a semiconductor device processing facility during operation; a hydrofluoric acid analyzer operably coupled to the hydrofluoric acid collection container, the hydrofluoric acid analyzer generating a signal indicating the concentration of the hydrofluoric acid in the hydrofluoric acid waste collection container during operation; a reactor in fluid communication with the hydrofluoric acid collection container; a reactant container in fluid communication with the reactor; one or more controllers, the one or more controllers controlling the amount of hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor during operation, and receiving a signal indicating the flow rate of the hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor; and controlling the amount of reactant introduced from the reactant container into the reactor based on the amount of hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor, and receiving a signal indicating the flow rate of the reactant introduced into the reactor.

[0067] In some embodiments, the system further includes a thermal energy transfer unit in thermal communication with the reactor.

[0068] In some embodiments, the system further includes a thermal energy conversion unit in communication with the thermal energy transfer unit, the thermal energy conversion unit being configured to convert thermal energy from the thermal energy transfer unit into a selectable energy form different from thermal energy.

[0069] In some embodiments, the hydrofluoric acid collection vessel includes a first inlet for receiving spent hydrofluoric acid from a first spent hydrofluoric acid source and a second inlet for receiving spent hydrofluoric acid from a second spent hydrofluoric acid source different from the first spent hydrofluoric acid source.

[0070] Still other embodiments of the present application provide a system for converting hydrofluoric acid into cryolite, the system comprising: a hydrofluoric acid collection container, the hydrofluoric acid collection container being operably in communication with at least one quantity determination unit and a hydrofluoric acid analyzer, the quantity determination unit generating a signal indicating the quantity of hydrofluoric acid in the hydrofluoric acid collection container during operation, the hydrofluoric acid analyzer generating a signal indicating the quantity of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container during operation; a reactor in fluid communication with the hydrofluoric acid collection container; a heat transfer unit in thermal communication with the reactor; a reactant container in fluid communication with the reactor; and at least one controller, the at least one controller controlling the quantity of reactants introduced into the reactor from the reactant source based on the signal indicating the quantity of hydrofluoric acid in the hydrofluoric acid collection container and the signal indicating the quantity of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container during operation.

[0071] In some embodiments, the hydrofluoric acid collection container is in fluid communication with two or more hydrofluoric acid waste sources in a semiconductor device manufacturing facility.

[0072] In some embodiments, the hydrofluoric acid from two or more sources comprises different amounts of hydrogen fluoride per unit mass or unit volume.

[0073] In some embodiments, the amount of the hydrofluoric acid in the hydrofluoric acid collection container is the mass of the hydrofluoric acid solution in the hydrofluoric acid waste collection container, and the amount of the hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container is the weight percentage of the hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container.

[0074] In some embodiments, the system further includes a thermal energy conversion unit in communication with the thermal energy transfer unit, the thermal energy conversion unit being configured to convert thermal energy from the thermal energy transfer unit into a selectable energy form different from thermal energy.

[0075] In some embodiments, the quantity determining unit is a load sensor.

[0076] In some embodiments, the system further includes a reactant concentration analysis unit in fluid communication with the reactant source.

Claims

1. A method for converting waste hydrofluoric acid into cryolite, comprising: collecting the waste hydrofluoric acid in a hydrofluoric acid waste collection container; generating a signal indicative of an amount of hydrofluoric acid in the hydrofluoric acid waste collection container; generating a signal indicative of an amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container; delivering hydrofluoric acid from the hydrofluoric acid waste collection container to a reactor; controlling the amount of reactants introduced into the reactor, the controlling the amount of reactants introduced into the reactor comprising determining a dosage of the reactants introduced into the reactor based on the generated signal indicating the amount of hydrofluoric acid in the hydrofluoric acid waste collection container and the generated signal indicating the amount of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container; as well as The temperature of the contents of the reactor is adjusted.

2. The method according to claim 1, wherein: Collecting the waste hydrofluoric acid includes collecting hydrofluoric acid waste from two or more hydrofluoric acid waste sources in a semiconductor device processing facility.

3. The method according to claim 2, wherein: The hydrofluoric acid waste from the two or more sources contains different amounts of hydrogen fluoride.

4. The method of claim 1 further comprising reacting the hydrofluoric acid in the reactor with the reactants in the reactor to form cryolite. 5 . The method of claim 4 , further comprising removing heat energy generated by forming cryolite in the reactor from the reactor, and delivering the removed heat energy to a thermal energy conversion unit.

6. The method of claim 5, further comprising receiving the thermal energy from the reactor at the thermal energy conversion unit and utilizing the received thermal energy to generate an alternative energy form other than thermal energy.

7. The method according to claim 6, wherein: The alternative form of energy is electrical energy.

8. The method according to claim 1, wherein: The amount of the hydrofluoric acid in the hydrofluoric acid waste collection container is the mass of the hydrofluoric acid solution in the hydrofluoric acid waste collection container, and the amount of the hydrogen fluoride in the hydrofluoric acid is the weight percentage of the hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid waste collection container.

9. A system for converting spent hydrofluoric acid into cryolite, the system comprising: a hydrofluoric acid collection container operable to receive waste hydrofluoric acid from two or more hydrofluoric acid waste sources in a semiconductor device processing facility; a hydrofluoric acid analyzer operably coupled to the hydrofluoric acid collection container, the hydrofluoric acid analyzer being operable to generate a signal indicative of a concentration of the hydrofluoric acid in the hydrofluoric acid waste collection container; a reactor in fluid communication with the hydrofluoric acid collection vessel; a reactant container in fluid communication with the reactor; one or more controllers operable to control the amount of hydrofluoric acid introduced into the reactor from the hydrofluoric acid collection vessel and to receive a signal indicative of a flow rate of hydrofluoric acid introduced into the reactor from the hydrofluoric acid collection vessel; as well as The amount of reactant introduced from the reactant container into the reactor is controlled based on the amount of the hydrofluoric acid introduced from the hydrofluoric acid collection container into the reactor, and a signal indicative of the flow rate of the reactant introduced into the reactor is received.

10. A system for converting hydrofluoric acid into cryolite, the system comprising: a hydrofluoric acid collection container in operable communication with at least one quantity determination unit, the quantity determination unit being operable to generate a signal indicative of the quantity of hydrofluoric acid in the hydrofluoric acid collection container and a hydrofluoric acid analyzer being operable to generate a signal indicative of the quantity of hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection container; a reactor in fluid communication with the hydrofluoric acid collection vessel; a thermal energy transfer unit in thermal communication with the reactor; a reactant container in fluid communication with the reactor; as well as At least one controller is operable to control an amount of reactant introduced into the reactor from the reactant source based on a signal indicative of an amount of the hydrofluoric acid in the hydrofluoric acid collection vessel and a signal indicative of an amount of the hydrogen fluoride in the hydrofluoric acid in the hydrofluoric acid collection vessel.

Images