Chemical substance supply source vessel and reaction system

Abstract

To provide a chemical substance supply source vessel, and a reaction system.SOLUTION: A chemical substance vessel used for holding a liquid chemical precursor includes a liquid level sensor tube. The liquid level sensor tube constituted so as to operate in an environment in which the liquid chemical precursor is heated to the boiling or evaporating point includes a housing including a slot built in for preventing the incorrect measurement of a sensor arranged in the liquid level sensor tube. The liquid level sensor tube can be protected from splashing an undesirable liquid by a shield while introducing a liquid into the environment; the liquid may be introduced through an inlet port; a splash wall may be between the liquid level sensor tube and the inlet port; and thereby a risk that the undesirable liquid is displaced on the liquid level sensor tube is reduced.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure generally relates to an apparatus for processing semiconductor wafers. More specifically, the present disclosure relates to a liquid level sensor for a container in an apparatus for supplying vaporized gas precursors from liquid sources used in a system for depositing films on semiconductor wafers, for example, in an atomic layer deposition (ALD) process, a chemical vapor deposition (CVD) process, or an epitaxial deposition process. The liquid level sensor may be for use in a high temperature environment or an environment where the liquid boils or vaporizes to a gas. [Background technology]

[0002] In a film deposition system, a gas is passed over a semiconductor wafer whereby the gas reacts with another gaseous precursor to form a particular film, which may be produced by boiling or vaporizing a liquid in a container.

[0003] It can be important to know the amount of precursor in the vessel in order to monitor the amount of vapor produced and the amount of liquid remaining. Monitoring can be achieved through the use of a liquid level sensor, such as that described in U.S. Patent No. 6,277,999 to Birtcher et al., entitled "Ultrasonic Liquid Level Sensing Systems." With proper monitoring of the vessel, refilling of the vessel may be performed as needed.

[0004] However, the process of boiling or vaporizing the liquid in the container can cause bubbles to rise in the conventional level sensor tube, resulting in erroneous readings from conventional level sensors that may result from random wet and dry signals, but can trigger safety measures in chemical containers and systems for depositing semiconductor films.

[0005] As a result, an accurate liquid level sensor is desired for use in high temperature or boiling environments within a chemical source vessel. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 10,151,618 Summary of the Invention

[0007] A chemical container for supplying chemical precursors for use in depositing semiconductor films on a substrate is disclosed. The chemical container includes a container housing and a level sensor tube extending from a top of the container housing, the level sensor tube including a level sensor tube housing, a slot constructed in the level sensor tube housing, and a plurality of sensors disposed in the level sensor tube housing, the plurality of sensors configured to indicate a level of the liquid chemical precursor in the container housing. According to an embodiment of the present disclosure, the chemical container further includes a shield coupled to the top of the container housing and surrounding at least a portion of the level sensor tube housing, and / or a splash wall extending vertically from the top of the container housing between the level sensor tube housing and the inlet port.

[0008] This summary is provided to introduce some concepts in a simplified form that are described in more detail below in the detailed description of exemplary embodiments of this disclosure. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other features, aspects, and advantages of the inventions disclosed in this disclosure will now be described with reference to the drawings of certain specific embodiments, which are intended to be illustrative of the invention and not limiting of the invention. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a perspective view of a chemical container in accordance with at least one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a chemical container in accordance with at least one embodiment of the present invention. [Figure 3A] FIG. 3A is a perspective view of a liquid level sensor in accordance with at least one embodiment of the present invention. [Figure 3B] FIG. 3B is a cross-sectional view of a liquid level sensor in accordance with at least one embodiment of the present invention. [Figure 4A] FIG. 4A is a perspective view of a liquid level sensor in accordance with at least one embodiment of the present invention. [Figure 4B] FIG. 4B is a cross-sectional view of a liquid level sensor in accordance with at least one embodiment of the present invention. [Figure 5A] FIG. 5A is a perspective view of a liquid level sensor in accordance with at least one embodiment of the present invention. [Figure 5B] FIG. 5B is a cross-sectional view of a liquid level sensor in accordance with at least one embodiment of the present invention. [Figure 6] FIG. 6 is a schematic diagram of a reaction system in accordance with at least one embodiment of the present invention. [Figure 7] FIG. 7 is a perspective view of a chemical container in accordance with at least one embodiment of the present invention. [Figure 8] FIG. 8 is a perspective view of a chemical container in accordance with at least one embodiment of the present invention. [Figure 9] FIG. 9 is a perspective view of a chemical container in accordance with at least one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] It will be understood that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0012] While certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the scope of the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious variations and equivalents thereof. It is therefore not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0013] The figures shown in this disclosure are not meant to be actual illustrations of any particular materials, structures or devices, but merely idealized representations used to describe embodiments of the present disclosure.

[0014] As used in this disclosure, the term "atomic layer deposition" (ALD) can refer to a vapor deposition process in which deposition cycles, preferably multiple consecutive deposition cycles, are performed in a process chamber. Typically, during each cycle, a precursor is chemisorbed to a deposition surface (e.g., a substrate surface or a previously deposited underlying surface, such as material from a previous ALD cycle) to form a monolayer or quasi-monolayer that does not readily react with additional precursors (i.e., a self-limiting reaction). If desired, a reactant (e.g., another precursor or reactant gas) can then be introduced into the process chamber for use in converting the chemisorbed precursor to the desired material on the deposition surface. Typically, this reactant can further react with the precursor. Additionally, a purge step can also be utilized during each cycle to remove excess precursor from the process chamber after conversion of the chemisorbed precursor and / or to remove excess reactants and reaction by-products from the process chamber. Furthermore, the term "atomic layer deposition" as used in this disclosure is also meant to include processes denoted by related terms, such as "chemical vapor deposition atomic layer deposition," "atomic layer epitaxy" (ALE), molecular beam epitaxy (MBE), gas source MBE, or metalorganic MBE, as well as chemical beam epitaxy when performed with alternating pulses of precursor compositions, reactive gases, and purge (e.g., inert carrier) gases.

[0015] As used in this disclosure, the term "chemical vapor deposition" (CVD) can refer to any process in which a substrate is exposed to one or more volatile precursors that can react and / or decompose on the substrate surface to produce a desired deposit.

[0016] A chemical reservoir can be used to hold a liquid precursor that is subsequently vaporized when used to form a semiconductor film. Figure 1 illustrates a chemical reservoir 100 in accordance with at least one embodiment of the present invention. The chemical reservoir 100 includes a reservoir housing 110, a first valve 120A, a second valve 120B, a third valve 120C, and a liquid level sensor port 130.

[0017] The first valve 120A may be connected to a gas source (not shown). The second valve 120B may be connected to a vacuum or liquid source (not shown). The third valve 120C may be connected to a reaction chamber (not shown) where film deposition can occur. The valves 120A-120C may be configured with manual or pneumatic valves. The level sensor port 130 may be configured to allow electrical connection to a controller, processor, thermocouple, or heating element (not shown). These electrical connections may be located elsewhere on the chemical container 100.

[0018] The chemical substance container 100 may be configured with other components as illustrated in Figure 2. The chemical substance container 100 may also be configured with a level sensor tube 140 and a plurality of sensors 150A-150D. The level sensor tube 140 may be connected to the level sensor tube port 130.

[0019] Multiple sensors 150A-150D may be positioned at specific locations along the level sensor tube 140 to indicate specific levels of liquid within the container housing 110. For example, a reading from sensor 150A may indicate that the liquid within the container housing 110 is 75% full, a reading from sensor 150B may indicate that the liquid within the container housing 110 is 65% full, a reading from sensor 150C may indicate that the liquid within the container housing 110 is 5% full, and a reading from sensor 150D may indicate that the liquid within the container housing 110 is 1% full. Sensors 150A-150D may be positioned at other levels to indicate other liquid levels within the container housing 110. The level sensor tube 140 may be configured with a slot 160 to allow for accurate measurement of the liquid within the container housing 110 when the liquid is boiling.

[0020] A conventional approach uses a level sensor tube with a circular shape without a slot, similar in shape to a drinking straw. The level sensor tube of the conventional approach would have a fluid chamber in the middle. While a level sensor tube according to at least one embodiment of the present invention may be made with a different shape, the presence of the slot 160 will allow for accurate measurement of the liquid level without false readings.

[0021] 3A illustrates a liquid level sensor tube 300 in accordance with at least one embodiment of the present invention. The liquid level sensor tube 300 comprises a U-shaped housing 310 with a slot / channel 320 built into the liquid level sensor tube 300. The U-shaped housing 310 may be constructed of metal (such as stainless steel), plastic (such as Teflon), ceramic, or any combination thereof, so long as the material has the ability to withstand a boiling environment of potentially corrosive chemicals.

[0022] The slot / channel 320 is illustrated as rectangular in shape. The slot / channel 320 may be continuously open throughout the entire level sensor tube 300 or may be closed at regular intervals along the level sensor tube 300. The slot / channel 320 may diffuse the surface tension of bubbles that form when the liquid in the chemical container boils or vaporizes. By reducing the surface tension of bubbles that form, this may prevent false readings from the sensor in the level sensor tube 300. Additionally, a fully open channel / slot 320 may allow the pressure measured within the slot / channel 320 to equalize with the pressure of the liquid surrounding the level sensor tube 300, or the liquid in the chemical container 100 generally.

[0023] Conventional approaches to level sensor tubes may use completely closed tubes with several vents. This can create a difference in pressure between the inside of the level sensor tube and the outside of the tube in the container, leading to a higher level being measured by the level sensor. A design according to at least one embodiment of the present invention can equalize the pressure inside and outside the level sensor tube, reducing false level readings during high-speed pulse operation.

[0024] FIG. 3B shows a cross section of the level sensor tube 300 at the location where the sensors are located. The U-shaped housing 310 of the level sensor tube 300 is composed of two sections: an outer housing section 310A and an inner housing section 310B. The level sensor tube 300 also includes a first sensor 330A and a second sensor 330B. The first sensor 330A and the second sensor 330B may be ultrasonic sensors, piezoelectric sensors, capacitance sensors, conductance sensors, or photoelectric sensors. The first sensor 330A may be a signal transmitter, and the second sensor 330B may be a signal receiver. The first sensor 330A may also be both a signal transmitter and a signal receiver, and the second sensor 330B may be a signal reflector. Furthermore, it may be possible to configure both the first sensor 330A and the second sensor 330B to function as both a signal transmitter and a signal receiver.

[0025] The outer housing portion 310A is sealed to the inner housing portion 310B with caps placed on the top and bottom of the level sensor tube 300 to provide a sealed, dry environment within the U-shaped housing 310. The sealed, dry environment protects the first sensor 330A and the second sensor 330B from the liquid within the chemical container.

[0026] 4A illustrates a level sensor tube 400 in accordance with at least one embodiment of the present invention. The level sensor tube 400 comprises a circular housing 410 with slots / channels 420 incorporated into the level sensor tube 400. The circular housing 410 may be constructed of metal (such as stainless steel), plastic (such as Teflon), ceramic, or any combination thereof, so long as the material has the ability to withstand a boiling environment of potentially corrosive chemicals.

[0027] The slot / channel is shown as a rectangular shape. The provision of the slot / channel 420 can diffuse the surface tension of bubbles that form when the liquid in the chemical container boils or vaporizes. By reducing the surface tension of the bubbles that form, this can prevent false readings from the sensor in the level sensor tube 400. Additionally, a fully open channel / slot 420 can allow the pressure measured in the slot / channel 420 to equalize with the pressure of the liquid surrounding the level sensor tube 400, or the liquid in the chemical container 100 in general.

[0028] Conventional approaches to level sensor tubes may use completely closed tubes with several vents, which can create a difference in pressure between the level sensor tube and the pressure outside the tube in the vessel, potentially resulting in higher level readings from the level sensor. A design in accordance with at least one embodiment of the present invention may equalize pressure inside and outside the level sensor tube, reducing false level readings during high-speed pulse operation.

[0029] FIG. 4B shows a cross section of the level sensor tube 400 at the location where the sensors are located. The circular housing 410 of the level sensor tube 400 is composed of two sections: an outer housing section 410A and an inner housing section 410B. The level sensor tube 400 also includes a first sensor 430A and a second sensor 430B. The first sensor 430A and the second sensor 430B may be configured to include, for example, an ultrasonic sensor, a piezoelectric sensor, a capacitance sensor, a conductance sensor, or a photoelectric sensor. The first sensor 430A may be a signal transmitter, and the second sensor 430B may be a signal receiver. Alternatively, the first sensor 430A may function as both a signal transmitter and a signal receiver, and the second sensor 430B may be a signal reflector. Furthermore, it may be possible to configure both the first sensor 430A and the second sensor 430B to function as both a signal transmitter and a signal receiver.

[0030] The outer housing portion 410A is sealed to the inner housing portion 410B with caps placed on the top and bottom of the level sensor tube 400 to provide a sealed, dry environment within the circular housing 410. The sealed, dry environment protects the first sensor 430A and the second sensor 430B from the liquid within the chemical container.

[0031] 5A illustrates a level sensor tube 500 in accordance with at least one embodiment of the present invention. The level sensor tube 500 includes a circular housing 510 having a rounded slot 520 incorporated into the level sensor tube 500. The circular housing 510 may be constructed of a metal (such as stainless steel), a plastic (such as Teflon), a ceramic, or any combination thereof, so long as the material has the ability to withstand a boiling environment of potentially corrosive chemicals.

[0032] The rounded slot / channel 520 is illustrated as having at least one rounded surface. Providing the rounded slot 520 can diffuse the surface tension of bubbles that form when the liquid in the chemical container boils or vaporizes. By reducing the surface tension of bubbles that form, this can prevent false readings from the sensor in the level sensor tube 500. Additionally, a fully open channel / slot 520 can allow the pressure measured within the slot / channel 520 to equalize with the pressure of the liquid surrounding the level sensor tube 500, or the liquid in the chemical container 100 generally.

[0033] Conventional approaches to level sensor tubes may use completely closed tubes with several vents. This can create a difference in pressure between the inside of the level sensor tube and the outside of the tube in the container, leading to higher level readings by the level sensor. A design according to at least one embodiment of the present invention may equalize the pressure inside and outside the level sensor tube, reducing false level readings during high-speed pulse operation.

[0034] FIG. 5B illustrates a cross section of the level sensor tube 500 at a location where a sensor is located. The circular housing 510 of the level sensor tube 500 includes two sections: an outer housing section 510A and an inner housing section 510B. The level sensor tube 500 also includes a first sensor 530A and a second sensor 530B. The first sensor 530A and the second sensor 530B may be configured to include an ultrasonic sensor, a piezoelectric sensor, a capacitance sensor, a conductance sensor, or a photoelectric sensor. The first sensor 530A may be configured to be a signal transmitter, and the second sensor 530B may be configured to be a signal receiver. The first sensor 530A may be configured to function as both a signal transmitter and a signal receiver, and the second sensor 530B may be configured to be a signal reflector. The first sensor 530A and the second sensor 530B may also be configured to function as both a signal transmitter and a signal receiver.

[0035] The outer housing portion 510A is sealed to the inner housing portion 510B such that caps are located on the top and bottom of the level sensor tube 500 to provide a sealed, dry environment within the circular housing 510. The sealed, dry environment allows the first sensor 530A and the second sensor 530B to be protected from the liquid within the chemical container.

[0036] 6 illustrates a reaction system 600 in accordance with at least one embodiment of the present invention. The reaction system 600 may include a precursor container 610, a carrier gas source 620, a liquid refill source 630, and a reaction chamber 640. The precursor container 610 includes the aforementioned container and liquid level sensor. The (optional) carrier gas source 620 supplies a carrier gas (e.g., nitrogen or other inert gas) to the precursor container 610, which carries vaporized precursor from the precursor container 610 into the reaction chamber 640, where the vaporized precursor reacts on a semiconductor wafer disposed therein. The liquid refill source 630 may be configured to supply additional liquid precursor to the precursor container 610 if the liquid level sensor determines that the level of liquid precursor in the precursor container 610 is too low.

[0037] 7 illustrates a chemical container 700 in accordance with at least one embodiment of the present disclosure. The chemical container 700 can be used as a precursor container 610 in a reaction system 600. The chemical container 700 includes a container housing 710, a first valve 720A, a second valve 720B, a third valve 720C, and a level sensor port 730.

[0038] The first valve 720A may be connected to a vacuum or liquid source (not shown). The second valve 720B may be connected to a gas source (not shown). The third valve 720C may be connected to a reaction chamber (not shown) where film deposition can occur. The valves 720A-720C may include manual or pneumatic valves. The level sensor port 730 may be configured to allow electrical connection to a controller, processor, thermocouple, or heating element (not shown). These electrical connections may be located elsewhere in the chemical container 700.

[0039] Chemical container 700 may include additional components similar to those shown in FIGS. 2-5B. Chemical container 700 may also include a level sensor tube 740 (such as level sensor tube 140 or other level sensor tube embodiments described herein) and multiple sensors (such as sensors 150A-150D). Level sensor tube 740 may be coupled to level sensor port 730. Container housing 710 includes a container housing top 780, which includes valve inlet ports 760A-760C in fluid communication with valves 720A-720C. Container housing 710 also includes a container housing bottom 785.

[0040] When the liquid precursor is injected into the container housing 710, some of the liquid precursor 750 may splash onto the level sensor tube 740, potentially resulting in an erroneous reading of the liquid level in the container housing 710. Therefore, it is desirable to protect the level sensor tube 740 from unintentional contact with the liquid precursor 750. A shield 790 can be attached to the container housing upper portion 780 to enclose a portion of the level sensor tube 740 and protect it from splashing of the liquid precursor 750. The shield 790 can be welded to the container housing upper portion 780. In other embodiments, the shield 790 can be welded to the bottom of the container housing, leaving a gap between the shield 790 and the container housing upper portion 280. The gap can be between about 0.5 millimeters and about 3 millimeters, or between about 1 millimeter and about 2 millimeters.

[0041] The shield 790 has a top portion 792 that circumferentially surrounds the level sensor tube 740 and a bottom portion 796 that partially surrounds the level sensor tube 740. The shield 790 includes a cover wall 794, which is a region of the shield that extends vertically from the top portion 792 to the bottom portion 796. The shield 790 has an opening 798 that is a gap from the top portion 792 to the bottom portion 796. The shield 790 may be configured to extend from the vessel housing top portion 780 to a distance between about 5 millimeters and about 1 millimeter from the vessel housing bottom portion 785, or between about 2 millimeters and about 1 millimeter from the vessel housing bottom portion 785.

[0042] In accordance with at least one embodiment of the present invention, the level sensor tube 740 may be configured with a slot (such as slot 160) that allows for measurement of the liquid level within the container housing 710. A cover wall 794 is positioned in front of the slot to prevent liquid from accidentally entering the slot. The perimeter of the upper portion 792 is configured to be approximately 1 millimeter to approximately 12 millimeters greater than the perimeter of the level sensor tube 740, approximately 2 millimeters to approximately 10 millimeters greater than the perimeter of the level sensor tube 740, or approximately 3 millimeters to approximately 9 millimeters greater than the perimeter of the level sensor tube 740.

[0043] 8 illustrates a chemical container 800 in accordance with at least one embodiment of the present invention. The chemical container 800 may be used as a precursor container 610 in a reaction system 600. The chemical container 800 includes a container housing 810, a first valve 820A, a second valve 820B, a third valve 820C, and a level sensor port 830.

[0044] The first valve 820A may be connected to a vacuum or liquid source (not shown). The second valve 820B may be connected to a reaction chamber (not shown) where film deposition can occur. The third valve 820C may be connected to a gas source (not shown). The valves 820A-820C may include manual or pneumatic valves. The level sensor port 830 may be configured to allow electrical connection to a controller, processor, thermocouple, or heating element (not shown). These electrical connections may be located elsewhere in the chemical container 800.

[0045] Chemical container 800 may include additional components similar to those shown in FIGS. 2-5B. Chemical container 800 may also include a level sensor tube 840 (such as level sensor tube 140 or other level sensor tube embodiments described herein) and multiple sensors (such as sensors 150A-150D). Level sensor tube 840 may be coupled to level sensor port 830. Container housing 810 includes container housing top 880, which includes valve inlet ports 860A-860C in fluid communication with valves 820A-820C. Container housing 810 also includes container housing bottom 885.

[0046] The splash wall 890 is coupled to and extends vertically from the vessel housing top 880. The top surface of the splash wall (not shown) is connected (e.g., fixedly) to the vessel housing top 880 at the valve inlet port 860A. The splash wall 890 is configured to be disposed between the level sensor tube 840 and the inlet port 860A. The splash wall 890 is thus fluidly connected to the valve inlet port 860A and configured to prevent injection of precursor into the chemical vessel 800 from contacting the top of the level sensor 840. In certain embodiments, the top surface of the splash wall may be welded to the vessel housing top 880. The splash wall 890 has a bottom surface (not shown) that extends from about 10 millimeters to about 20 millimeters from the vessel housing top 880, or from about 10 millimeters to about 15 millimeters from the vessel housing top 880.

[0047] 9 illustrates a chemical container 900 in accordance with at least one embodiment of the present invention. The chemical container 900 may be used as a precursor container 610 in a reaction system 600. The chemical container 900 includes a container housing 910, a first valve 920A, a second valve 920B, a third valve 920C, and a level sensor port 930.

[0048] The first valve 920A may be connected to a vacuum or liquid source (not shown). The second valve 920B may be connected to a reaction chamber (not shown) where film deposition can occur. The third valve 920C may be connected to a gas source (not shown). The valves 920A-920C may include manual or pneumatic valves. The level sensor port 930 may be configured to allow electrical connection to a controller, a processor, a thermocouple, or a heating element (not shown). These electrical connections may be located elsewhere in the chemical container 900.

[0049] Chemical container 900 may include additional components similar to those shown in FIGS. 2-5B. Chemical container 900 may also include a level sensor tube 940 (such as level sensor tube 140 or other level sensor tube embodiments described herein) and multiple sensors (such as sensors 150A-150D). Level sensor tube 940 may be coupled to level sensor port 930. Container housing 910 includes a container housing top 980 having valve inlet ports 960A-960C in fluid communication with valves 920A-920C. Container housing 910 also includes a container housing bottom 985.

[0050] The splash wall 990 is coupled to and extends vertically from the vessel housing top 980. An upper surface (not shown) of the splash wall is (e.g., fixedly) coupled to the vessel housing top 980. The splash wall 990 is configured to be between the level sensor tube 940 and the valve inlet port 960A. Thus, the splash wall 990 is configured to prevent introduction of precursor into the chemical vessel 900 from contacting the top of the level sensor 940. In certain embodiments, the upper surface of the splash wall may be welded to the vessel housing top 980. The splash wall 990 includes a splash wall bottom surface (not shown) that may extend from the vessel housing top 980 to the vessel housing bottom 985, or between about 10 millimeters and about 20 millimeters from the vessel housing top 980, or between about 10 millimeters and about 15 millimeters from the vessel housing top 980.

[0051] The specific implementations shown and described are illustrative of the present invention and its best mode and are in no way intended to limit the scope of aspects and implementations. Also, for the sake of brevity, conventional manufacturing, association, preparation, and other functional aspects of the systems may not be described in detail. Furthermore, connecting lines shown in the various figures are intended to represent example functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in an actual system and / or may not be present in some embodiments.

[0052] It will be understood that the configurations and / or approaches described in this disclosure are exemplary in nature, and that these specific embodiments or examples are not to be construed in a limiting sense, as numerous variations are possible. The specific routines or methods described in this disclosure may represent one or more of any number of process strategies. As such, the various illustrated operations may be performed in the order illustrated, in other orders, or omitted in some cases.

[0053] The subject matter of this disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, as well as other configurations, functions, operations and / or properties disclosed in this disclosure, as well as any and all equivalents thereof. [Explanation of symbols]

[0054] 100 chemical containers 110 container housing 130 Liquid level sensor port 140, 740, 840, 940 Liquid level sensor tube 790 Shield

Claims

1. 1. A chemical container comprising: a vessel housing having a level sensor port; a level sensor tube extending vertically into the container housing at a fixed depth from the top of the container housing; a level sensor tube housing having an outer surface in direct contact with a liquid chemical precursor contained within the container housing and having a sealed environment within the container housing that is protected from the liquid chemical precursor, the level sensor tube housing having a slot extending substantially the entire length of the level sensor tube housing and configured to receive a placement of the liquid chemical precursor therein; a plurality of sensors disposed within the level sensor tube housing in the sealed environment at specific vertical positions along the level sensor tube that are associated with specific liquid levels of the chemical precursor within the vessel housing, at least one of the plurality of sensors contacting an inner wall surface of the level sensor tube housing; a liquid level sensor tube comprising: a shield coupled to the top of the container housing and surrounding at least a portion of the level sensor tube housing, the shield including a cover wall extending vertically from the top of the container housing; 1. A chemical container comprising:

2. 10. The chemical container of claim 1, wherein the level sensor tube housing comprises an outer housing portion connected to an inner housing portion, and wherein the at least one of the plurality of sensors contacts an inner wall surface of the inner housing portion of the level sensor tube housing.

3. 10. The chemical container of claim 1, wherein the shield extends vertically from the top of the container housing to within a range of about 2 millimeters to about 1 millimeter from the bottom of the container housing.

4. 10. The chemical container of claim 1, wherein the shield extends vertically from the top of the container housing to the bottom of the container housing.

5. The chemical container of claim 1 , wherein the cover wall is disposed forward of the slot.

6. 10. The chemical container of claim 1, wherein the shield has an opening extending from a top of the shield to a bottom of the shield.

7. The cover wall is an upper portion circumferentially surrounding the level sensor tube; a bottom portion partially surrounding the level sensor tube; 10. The chemical container of claim 1, comprising:

8. 10. The chemical container of claim 1, wherein the shield is welded to the top of the container housing.

9. 1. A reaction system comprising: A container comprising: a vessel housing having a liquid level sensor port; a level sensor tube extending longitudinally into the container housing from the top of the container housing to a fixed depth; a level sensor tube housing having an outer surface in direct contact with a liquid disposed within the container housing and having a sealed environment within the container housing that is protected from the liquid, the level sensor tube housing having a slot extending along a length along the level sensor tube housing and configured to receive the liquid disposed therein; a plurality of sensors disposed within the level sensor tube housing within the sealed environment, the plurality of sensors located at specific vertical positions along the level sensor tube that are associated with specific levels of the liquid within the container housing, at least one of the plurality of sensors contacting an inner wall surface of the level sensor tube housing; a liquid level sensor tube comprising: a shield coupled to the top of the container housing and surrounding at least a portion of the level sensor tube housing, the shield including a cover wall extending vertically from the top of the container housing; a container comprising: a reaction chamber configured to hold a substrate and configured to receive gas from the vessel; a liquid refill source configured to supply additional liquid to the container; A reaction system comprising:

10. 10. The reaction system of claim 9, wherein the shield extends vertically from the top of the vessel housing to within a range of about 2 millimeters to about 1 millimeter of the bottom of the vessel housing.

11. 10. The reaction system of claim 9, wherein the shield extends vertically from the top of the vessel housing to the bottom of the vessel housing.

12. 10. The reaction system of claim 9, wherein the cover wall is disposed in front of the slot.

13. 10. The reaction system of claim 9, wherein the shield has an opening extending from the top of the shield to the bottom of the shield.

14. The cover wall is an upper portion circumferentially surrounding the level sensor tube; a bottom portion partially surrounding the level sensor tube; 10. The reaction system of claim 9, comprising:

15. 10. The reaction system of claim 9, wherein the shield is welded to the top of the vessel housing.

16. 1. A chemical container comprising: a vessel housing having a level sensor port and an inlet port; a level sensor tube extending vertically into the container housing from a top of the container housing to a fixed depth; a level sensor tube housing having an outer surface in direct contact with a liquid disposed within the container housing and having a sealed environment within the container housing that is protected from the liquid, the level sensor tube housing having a slot extending substantially the entire length of the level sensor tube housing and configured to receive the liquid disposed therein; a plurality of sensors disposed within the level sensor tube housing within the sealed environment, the plurality of sensors located at specific vertical positions along the level sensor tube that are associated with specific levels of the liquid within the container housing, at least one of the plurality of sensors contacting an inner wall surface of the level sensor tube housing; a liquid level sensor tube comprising: a splash wall extending vertically from the top of the container housing between the level sensor tube and the inlet port; 1. A chemical container comprising:

17. 17. The chemical container of claim 16, wherein the splash wall extends vertically from the top of the container housing between about 10 millimeters and about 20 millimeters.

18. 17. The chemical container of claim 16, wherein the splash wall is fixedly connected to the top of the container housing.

19. 17. The chemical container of claim 16, wherein the splash wall is welded to the top of the container housing.

20. 17. The chemical container of claim 16, wherein the splash wall is circular and surrounds the inlet port.

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