Self-sensing and self-actuating valve for regulating process coolant flow

Abstract

The valve includes a first in-line section for attachment to a first return line exiting the processing chamber and a second in-line section for attachment to a second return line entering a coolant source. A flow section is attached between the first and second in-line sections through which the coolant returns to the coolant source. A first inlet orifice and a second inlet orifice are positioned between the first in-line and flow sections. A plunger has a tip for variably opening and closing the second inlet orifice. A shape memory alloy (SMA) spring is disposed on the plunger and attached to the tip, the SMA spring variably increasing or decreasing the flow rate of the coolant through the second inlet orifice according to the temperature of the coolant.

Description

[Technical field]

[0001] Some embodiments of the present disclosure relate generally to a self-sensing and self-actuating valve for regulating the flow of a process coolant. [Background technology]

[0002] Process coolants can be circulated throughout the process chambers (among other processing equipment) of a process tool to reduce heat dissipation in various processing components that generate temperatures of hundreds of degrees Celsius or more. Regulating the process coolant through the coolant lines of a process tool provides an opportunity to reduce the energy footprint of the process tool performing semiconductor device fabrication. The use of servo-controlled valves is one solution that is functional but involves additional cost and complexity of sensors, control logic, and actuators. Additionally, servo-controlled valves involve the overhead of adjusting control parameters for process tool setup, which can be time consuming and costly. Summary of the Invention

[0003] Some embodiments described herein are directed to a cooling system for cooling a process tool. For example, a cooling system according to one embodiment includes a coolant source for supplying a coolant to cool a heated component of a processing chamber, and a return line for the coolant coupled between the processing chamber and the coolant source. The return line has a valve, the valve including a flow section having a first inlet and an outlet supporting a default flow rate of the coolant, the flow section also having a second inlet. The valve further includes a first section in-line with the return line that will supply the coolant through the first inlet and the second inlet. The valve further includes a plunger having a tip at a distal end of the plunger, the tip variably opening and closing the second inlet to vary the flow rate of the coolant from the default flow rate. The valve further includes a bias spring positioned at a proximal end of the plunger. The valve further includes a shape memory alloy (SMA) spring positioned on the plunger between the bias spring and the tip, the SMA spring attached to the tip for variably withdrawing the tip from the second inlet in response to a temperature increase of the coolant above a threshold temperature value.

[0004] In some embodiments, a valve of a cooling system includes a flow section having a first inlet and an outlet supporting a default flow rate of coolant from a return line between a processing chamber and a coolant source, the flow section also having a second inlet. The valve further includes a first section in-line with the return line and adapted to supply coolant through the first inlet and the second inlet. The valve further includes a plunger having a tip at a distal end of the plunger, the tip variably opening and closing the second inlet to vary the flow rate of the coolant from the default flow rate. The valve further includes a bias spring positioned at a proximal end of the plunger. The valve further includes a shape memory alloy (SMA) spring positioned on the plunger between the bias spring and the tip, the SMA spring attached to the tip for variably withdrawing the tip from the second inlet in response to a temperature increase of the coolant above a threshold temperature value.

[0005] In some embodiments, the valve of the cooling system includes a first in-line section for attachment to a first return line exiting the processing chamber. The valve further includes a second in-line section for attachment to a second return line entering the coolant source. The valve further includes a flow section attached between the first in-line section and the second in-line section through which the coolant returns to the coolant source. The valve further includes a first inlet orifice and a second inlet orifice positioned between the first in-line section and the flow section. The valve further includes a plunger having a tip for variably opening and closing the second inlet orifice. The valve further includes a shape memory alloy (SMA) spring positioned on the plunger and attached to the tip for variably increasing and decreasing the flow rate of the coolant through the second inlet orifice according to the temperature of the coolant.

[0006] The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals indicate like elements. It should be noted that various references to "an" or "one" embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one embodiment, but may refer to multiple embodiments. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic block diagram of an exemplary processing system in accordance with an embodiment. [Figure 2A] 1 is a cross-sectional view of an exemplary valve for controlling the flow of coolant between a processing chamber and a coolant source while the coolant temperature is below a threshold temperature, according to an embodiment. [Figure 2B] FIG. 2B is a cross-sectional view of the example valve of FIG. 2A while the coolant temperature exceeds a threshold temperature value, according to an embodiment. [Diagram 3] 2C is a graph of an exemplary transition zone between low and high flow rates for the valve of FIGS. 2A-2B, according to an embodiment. [Figure 4]FIG. 3 is a schematic block diagram of a thermal model of the valve of FIGS. 2A-2B, according to some embodiments. [Diagram 5] 1 is a cross-sectional view of an exemplary dual-valve that controls the flow of coolant between a processing chamber and a coolant source while the coolant temperature is below a threshold temperature value, according to an embodiment. [Figure 6] 6 is a graph of an exemplary first transition zone between low and medium flow rates, and a second transition zone between medium and high flow rates, for the dual valve of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The embodiments of the present disclosure provide a self-sensing and self-actuating valve for regulating the flow of a process coolant, which overcomes the above-mentioned deficiencies in current servo-controlled solutions. Furthermore, regulating the flow of the process coolant can conserve thermal energy throughout the processing system (or tool) and attempt to maintain a constant flow rate of the coolant through the coolant line in a manner that is responsive to increases in the coolant temperature. In some embodiments, the valve can be mounted in-line on the return line of the coolant system between the processing chamber (or other processing equipment) and a coolant source, such as a coolant reservoir. The valve can also be adapted to mechanically restrict or increase the flow of the coolant through the return line based on the temperature of the coolant.

[0009] In one embodiment, the valve employs a multi-compartment approach, where an in-line compartment receives coolant from the process chamber and returns it to a coolant source, while a flow compartment attached between the in-line compartments allows the coolant to flow freely through the valve. Flow through the second of two orifices between the first in-line compartment (the input of the valve) and the flow compartment can be variably controlled by using a shape memory alloy (SMA) spring-enabled plunger with a tip capable of completely blocking the second orifice. The tip can be conical (e.g., cone-shaped) in one embodiment, for example, to allow for a variable level of blocking the second orifice.

[0010] More specifically, the valve may include a first in-line section for attachment to a first return line exiting the processing chamber. The valve may further include a second in-line section for attachment to a second return line entering the coolant source. The flow section may be attached between the first in-line section and the second in-line section through which the coolant will return to the coolant source. The valve may further include a first inlet orifice and a second inlet orifice positioned between the first in-line section and the flow section. The valve may further include a plunger having a tip for variably opening and closing the second inlet orifice to variably control the flow of the coolant through the valve. The valve may further include an SMA spring positioned on the plunger and attached to the tip. The SMA spring may variably increase or decrease the flow rate of the coolant through the second inlet orifice according to the temperature of the coolant.

[0011] Advantages of embodiments of the present disclosure include, but are not limited to, mechanically employed sensing and velocity modulation capabilities (via an SMA-enabled plunger in the valve) that eliminate the need for external sensors, control logic, or actuators, including the overhead required to adjust the control parameters of such servo-controlled solutions. Additionally, the disclosed valve does not require an external energy source as it utilizes the thermal energy of the exhausted coolant itself. Additionally, the valve can be adapted to function in either continuous flow regulation or predetermined step regulation based on the temperature of the coolant. Thus, the disclosed valve is cost-effective in reducing complexity and eliminating reliance on an external energy source. Additionally, the valve can be adapted to work with a variety of coolant types and corrosive environments. These and other advantages will be mentioned in the disclosure below and / or will be apparent to one of ordinary skill in the art of semiconductor device processing.

[0012] 1 is a schematic block diagram of an exemplary processing system 100 according to an embodiment. The processing system 100 (or processing tool) may include a processing chamber 102 representing processing equipment to be cooled, a coolant source 120 (e.g., in a coolant line) that supplies coolant to the processing chamber 102, and a valve 110 positioned on a return line 105 coupled between the processing chamber 102 and the coolant source 120. The return line 105 may include a first return line 105A attached between the coolant line of the processing chamber 102 and the valve 110, and a second return line 105B attached between the valve 110 and the coolant source 120. The valve 110 may be adapted to mechanically restrict or increase the flow of coolant through the return line based on the temperature of the coolant.

[0013] As previously discussed, the coolant source 120 may be a reservoir, container, etc. that is supplied with coolant through a facility fluid inlet and that allows for the coolant to be reused through a facility fluid outlet. The coolant may be, but need not be, an aqueous coolant. In one embodiment, the coolant is a mixed fluid that includes ununtrium (UUT). For example, ununtrium may be mixed with water and / or other fluids. In other embodiments, the coolant is gas-based and includes a mixed gas.

[0014] 2A is a side view of an exemplary valve 210 that controls the flow of coolant between a processing chamber and a coolant source while the coolant temperature is below a threshold temperature value, according to an embodiment. In this embodiment, the valve 210 can be identical to the valve 110 of FIG. 1. In various embodiments, the valve 210 includes a first compartment 204 (e.g., a first in-line compartment), a second compartment 208 (e.g., a second in-line compartment), and a flow compartment 206 attached between the first compartment 204 and the second compartment 208.

[0015] The flow section 206 may have a first inlet 203 (e.g., a first inlet orifice) and an outlet 207 (e.g., an outlet orifice) that support a default flow rate of coolant indicated by a single arrow, such as the default flow rate (GPM) of coolant from the first section 204 to the second section (com) or other acceptable low flow rate. In one embodiment, the low flow rate is 3.7 GPM. The flow section 206 may further include a second inlet 205 (e.g., a second inlet orifice best seen in FIG. 2B) to provide a variable additional flow of coolant through a valve 210.

[0016] In various embodiments, the first compartment 204 is in-line with the first return line 105A and supplies coolant through the first inlet 203 and the second inlet 205 into the flow compartment 206. In these embodiments, the second compartment 208 is in-line with the second return line 105B and includes an outlet 207. A second compartment partition 211 may block flow between the first compartment 204 and the second compartment 208.

[0017] In various embodiments, the valve 210 further includes a valve assembly including a plunger 212, a bias spring 230, a backstop 220, and an SMA spring 240. The plunger 212 may include or be attached to a flange 216 and a tip 224. In these embodiments, the tip 224 is positioned at a distal end of the plunger 212 to variably open and close the second inlet 205 to vary the flow rate of the coolant from a default flow rate. In some embodiments, the plunger is adapted to move perpendicular to the flow of the coolant through the flow section 206. In one embodiment, the tip 224 is conical, e.g., a conical tip. In other embodiments, the tip 224 is another geometric shape (e.g., spherical, block shaped with corners) that blocks the second inlet 205 and variably allows more coolant flow between the first section 204 and the flow section 203 when the tip 224 is withdrawn from the second inlet 205. Thus, the default flow rate of the valve 210 is the flow rate of coolant when the second inlet 205 is fully closed by the tip 224 .

[0018] In some embodiments, the biasing spring 230 is positioned at the proximal end of the plunger 212 and has a constant stiffness that biases the plunger 212 back into a position where the tip 224 blocks the second inlet 205. In various embodiments, the SMA spring 240 is positioned on the plunger between the biasing spring 230 and the tip 224. The SMA spring 240 can be attached to the tip 224 to variably withdraw the tip 224 from the second inlet 205 in response to an increase in the temperature of the coolant above a threshold temperature value (FIG. 2B). The SMA spring 240 can be made of (or can be configured with) a shape memory alloy that expands or contracts based on temperature, such as one of nickel titanium (Ni-Ti), nickel titanium iron (Ni-Ti-Fe), or nickel titanium copper (Ni-Ti-Cu), among other possibilities.

[0019] In various embodiments, the valve 210 further includes an orifice 217 (labeled in FIG. 2B ) in the first section 204 through which the plunger 212 is inserted. One or more extended walls 225 surround the orifice and may be attached (or formed) to an outer surface of the first section 204. The backstop 220 may be attached to the one or more extended walls 225 and contact a proximal end of a biasing spring 230. In these embodiments, a distal end of the biasing spring 230 may be biased against the flange 216. Additionally, an SMA spring 240 may be coupled between the inner wall of the first section 204 at the orifice 217 and the tip 224 of the plunger 212. In response to exposure to a coolant whose temperature increases above a threshold temperature value, the SMA spring 240 may be compressed against the inner wall, thereby variably withdrawing the tip 224 from the second inlet 205. The valve 210 and the various sections and components of the valve 210 discussed herein may be manufactured from components that are resistant to corrosive environments and function with a variety of different coolants.

[0020] 2B is a side view of the example valve 210 of FIG. 2A while the coolant temperature exceeds a threshold temperature value, according to an embodiment. Once the coolant temperature exceeds the threshold (e.g., 30° C., 33° C., 36° C., etc.), the SMA spring 240 compresses and the tip 224 of the plunger 212 begins to withdraw from the second inlet 205. The increase in coolant flow through the valve 210 is indicated by the double arrow. The SMA spring 240 may continue to compress proportionally (or according to a function) in response to the continued increase in temperature of the coolant until it reaches a maximum contraction rate and therefore a maximum flow rate. The maximum flow rate may be, for example, between 14-18 GPM, or any other suitable high flow rate, depending on the material of the SMA spring 240 and the temperature range of the coolant.

[0021] 3 is a graph 300 of an example transition zone 301 between low and high flow rates for the valve 210 of FIGS. 2A-2B, according to an embodiment. The graph 300 includes a valve open plot 302 and a valve closed plot 304, illustrating that the flow rate trajectory may change depending on whether the coolant is heating or cooling. As explained, the default (low) flow rate for the valve may be between 3-5 gallons per minute, and the maximum flow rate for the valve may be between 14-18 gallons per minute. These flow rate ranges could be adjusted depending on the type of alloy of the SMA spring 240 and / or the type of coolant and expected temperature range of the coolant.

[0022] 4 is a schematic block diagram of a thermal model 400 of the valve 210 of FIGS. 2A-2B in accordance with some embodiments. The thermal model 400 may assume a constant set point temperature (TS). The thermal model 400 may assume a first temperature (T1) entering the valve 210 from the first return line 105A, an average temperature within the valve 210 (T av ), and a second temperature (T2) of the coolant exiting the valve 210 and entering the second return line 105B. A resistor 440 is shown to model the function of the SMA spring 240. In various embodiments, TIFF0007630002000001.tif23170Here, K is a constant for the type of fluid. Therefore, from equations (1) and (2), the following is derived. TIFF0007630002000002.tif15170According to Dittus Boelter's equation, n=0.8, and therefore n-1 is -0.2. Therefore, Since TIFF0007630002000003.tif17170TIFF0007630002000004.tif12170, equation (4) has a nonlinear iterative correlation. The operating range of the valve should have a bandwidth to reduce temperature oscillations. Therefore, in some embodiments, m dot As increases, T2 decreases and the valve 210 operates at a lower m dot Triggers on and vice versa.

[0023] 5 is a cross-sectional view of an exemplary dual valve 510 for controlling the flow of coolant between a process chamber and a coolant source while the coolant temperature is below a threshold temperature value, according to an embodiment. In one embodiment, the dual valve 510 can be identical to the valve 110 of FIG. 1. The dual valve 510 can be understood as an extension of the valve 210 of FIGS. 2A-2B, and therefore only the changes are described here. For example, the first compartment 204 can be expanded to include a first inlet 203, a second inlet 205A, and a third inlet 205B.

[0024] In the dual valve 510 embodiments, instead of a single valve assembly, there are two valve assemblies, one each for selectively opening or closing the second inlet 205A and the third inlet 205B, respectively. Thus, the first valve assembly may include a first plunger 212A, a first bias spring 230A, and a first SMA spring 240A. The first plunger 212A may include or be attached to a first flange 216A and a first tip 224A. In these embodiments, the first tip 224A is positioned at a distal end of the first plunger 212A and variably opens and closes the second inlet 205A to vary the coolant flow rate from a default flow rate.

[0025] In some embodiments, the first bias spring 230A is positioned at the proximal end of the first plunger 212A and has a constant stiffness that biases the first plunger 212A back to a position where the first tip 224A blocks the second inlet 205A. In various embodiments, the first SMA spring 240A is positioned on the first plunger 212A between the first bias spring 230A and the first tip 224A. The first SMA spring 240A can be attached to the first tip 224A to variably withdraw the first tip 224A from the second inlet 205A in response to a rise in temperature of the coolant above a first threshold temperature value (FIG. 2B).

[0026] In these embodiments, the second valve assembly can include a second plunger 212B, a second bias spring 230B, and a second SMA spring 240B. The second plunger 212B can include or be attached to a second flange 216B and a second tip 224B. In these embodiments, the second tip 224B is positioned at a distal end of the second plunger 212B and variably opens and closes the third inlet 205B to vary the coolant flow rate from a default flow rate.

[0027] In some embodiments, the second bias spring 230B is positioned at a proximal end of the second plunger 212B and has a constant stiffness that biases the second plunger 212B back to a position where the second tip 224B blocks the third inlet 205B. In various embodiments, the second SMA spring 240B is positioned on the second plunger 212B between the second bias spring 230B and the second tip 224B. The second SMA spring 240B can be attached to the second tip 224B to variably withdraw the second tip 224B from the third inlet 205B in response to a rise in temperature of the coolant above a second threshold temperature value (FIG. 2B). The backstop 220 (FIGS. 2A-2B) may be modified to be larger such that it is attached to one or more extension walls 225 and adapted to contact the proximal ends of the first bias spring 230A and the second bias spring 203B.

[0028] In various embodiments, the first SMA spring 240A may be made of a different SMA material than the second SMA spring 240B, so that the first threshold temperature value may be different from the second threshold temperature value. For ease of explanation, it is assumed that the first threshold temperature value is lower than the second threshold temperature value. Thus, the first valve assembly may use the first SMA spring 240A to variably increase the flow rate through the dual valve 510 to approximately a medium flow rate, and then the second valve assembly may use the second SMA spring 240B to variably increase the flow rate from approximately the medium flow rate to a maximum flow rate. Thus, for example, at the maximum flow rate, both the first and second SMA springs 240A and 240B are fully compressed against the inner wall of the first compartment 204, as illustrated with reference to the single valve assembly in FIG. 2B. The gradual and variable increase in coolant flow rate is illustrated in the graph of FIG. 6.

[0029] 5 shows only two valve assemblies varying the flow rate, additional valve assemblies can be added that include one or more additional SMA springs of different materials, thereby allowing for an even larger bandwidth of variation in coolant flow rate in the multi-valve device. In some embodiments, the flow ranges of each valve assembly in a multi-valve device overlap to some extent, allowing even more possible flow rates to be created through the timing of flow rate increases via the actuation of one or more different SMA springs.

[0030] Figure 6 is a graph 600 of an exemplary first transition zone 601A between low and medium flow rates, and a second transition zone 601B between medium and high flow rates for the dual valve 510 of Figure 5. In some embodiments, as shown, the first transition zone 601A and the second transition zone 602B overlap to some extent, allowing the flow rate to gradually transition between opening and closing the valve assembly based on the different compression rates and threshold temperature values ​​associated with the different SMA springs.

[0031] 6, graph 600 includes a first valve open plot 602A and a first valve closed plot 604A for a first valve assembly of dual valve 510, illustrating that the flow trajectory may change depending on whether the coolant is being heated or cooled. Graph 600 further includes a second valve open plot 602B and a second valve closed plot 604B for a second valve assembly of dual valve 510, illustrating that the flow trajectory may further change depending on whether the coolant is being heated or cooled.

[0032] 6, with increasing temperature across the x-axis of graph 600, as the flow rate through the first valve assembly reaches a "med flow" amount in the middle of the y-axis, the flow rate through the second valve assembly begins to gradually increase. While the flow rate through the first valve assembly remains high (and perhaps at a maximum), the flow rate through the second valve assembly may gradually increase until it reaches the maximum flow rate of the dual valve 510. This further increase provides a higher potential flow rate, and therefore a larger overall flow range, of coolant through the dual valve 510 as compared to through valve 210 (FIGS. 2A-2B).

[0033] The foregoing description specifies numerous specific details, such as examples of specific systems, components, methods, etc., to provide a good understanding of some embodiments of the present disclosure. However, it will be apparent to those skilled in the art that at least some embodiments of the present disclosure can be practiced without these specific details. In other instances, well-known components or methods are not described in detail or are presented in simple block diagram form to avoid unnecessarily obscuring the present disclosure. Thus, the specific details described are merely exemplary. Certain implementations may differ from these example details and still be considered to be within the scope of the present disclosure.

[0034] Throughout this specification, reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. In addition, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". When the term "about" or "approximately" is used herein, it is intended to mean that the nominal value presented is accurate to within ±10%.

[0035] Although the steps of the methods herein are illustrated and described in a particular order, the order of the steps of each method may be changed such that certain steps are performed in reverse order, and certain steps are performed at least partially simultaneously with other steps. In alternative embodiments, the orders of the separate steps or sub-steps may be intermittent and / or alternating.

[0036] It should be understood that the above description is intended to be illustrative, and not limiting. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the above description. The scope of the disclosure should therefore be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. a coolant source for cooling components of the processing chamber; a return line for the coolant connected between the processing chamber and the coolant source; the return line having a valve, the valve comprising: a flow section having a first inlet and an outlet supporting a temperature independent default flow rate of the coolant, the flow section also having a second inlet; a plunger having a tip for variably opening and closing the second inlet to vary the flow rate of the coolant from the temperature independent default flow rate; a shape memory alloy (SMA) spring positioned on the plunger between an inside of the valve and the tip, the SMA spring attached to the tip for variably withdrawing the tip from the second inlet in response to a rise in temperature of the coolant above a threshold temperature value; a cooling system.

2. The cooling system of claim 1, further comprising a first compartment in-line with the return line and supplying the coolant into the flow compartment through the first inlet and the second inlet, and the inside of the valve on which the SMA spring is positioned is the inside of the first compartment.

3. The valve, a second section including the outlet and in-line with the return line; a partition that blocks flow between the first compartment and the second compartment; The cooling system of claim 2 further comprising:

4. The valve, a bias spring positioned at a proximal end of the plunger and biased against an exterior surface of the first section; an orifice in the first compartment into which the plunger is inserted; one or more extension walls surrounding the orifice and attached to the exterior surface; a backstop attached to the one or more extension walls and in contact with a proximal end of the bias spring; The cooling system of claim 2 further comprising:

5. 5. The cooling system of claim 4, wherein the SMA spring is coupled between an inner wall of the first section at the orifice and the tip of the plunger, the SMA spring compressing against the inner wall in response to exposure to a coolant increasing in temperature above the threshold temperature value.

6. The cooling system of claim 1, wherein the tip is conical.

7. The cooling system of claim 1, wherein the coolant is a mixed fluid including ununtrium, the temperature independent default flow rate of the valve comprises between 3 and 5 gallons per minute, and the maximum flow rate of the valve comprises between 14 and 18 gallons per minute.

8. a flow section having a first inlet and an outlet supporting a temperature independent default flow rate of coolant from a return line between the processing chamber and a coolant source, the flow section also having a second inlet; a plunger having a tip for variably opening and closing the second inlet to vary the flow rate of the coolant from the temperature independent default flow rate; a shape memory alloy (SMA) spring positioned on the plunger between an inside of the valve and the tip, the SMA spring attached to the tip for variably withdrawing the tip from the second inlet in response to a rise in temperature of the coolant above a threshold temperature value; A valve comprising:

9. A valve as described in claim 8, further comprising a first compartment in-line with the return line and supplying the coolant into the flow compartment through the first inlet and the second inlet, the inside of the valve on which the SMA spring is positioned being the inside of the first compartment.

10. a second section including the outlet and in-line with the return line; a partition that blocks flow between the first compartment and the second compartment; The valve of claim 9 further comprising:

11. A bias spring positioned at a proximal end of the plunger and biased against an outer surface of the first compartment; an orifice in the first compartment into which the plunger is inserted; one or more extension walls surrounding the orifice and attached to the exterior surface; a backstop attached to the one or more extension walls and in contact with a proximal end of the bias spring; The valve of claim 9 further comprising:

12. 12. The valve of claim 11, wherein the SMA spring is coupled between an inner wall of the first section at the orifice and the tip of the plunger, the SMA spring compressing against the inner wall in response to exposure to a coolant that increases in temperature above the threshold temperature value.

13. The valve of claim 8, wherein the tip is conical.

14. The valve of claim 8, wherein the coolant is a mixed fluid including ununtrium, the temperature independent default flow rate of the valve comprises between 3 and 5 gallons per minute, and the maximum flow rate of the valve comprises between 14 and 18 gallons per minute.

15. a flow section attached between the first in-line section and the second in-line section, through which coolant flows back to a coolant source; a first inlet orifice and a second inlet orifice shared with the first in-line section; an exit orifice shared with the second in-line section; and a plunger having a tip for variably opening and closing the second inlet orifice; a shape memory alloy (SMA) spring positioned on the plunger and attached to the tip, the SMA spring for variably increasing or decreasing a flow rate of the coolant through the second inlet orifice according to a temperature of the coolant; A valve comprising:

16. The method of claim 1, further comprising the steps of: attaching the first in-line section to a first return line exiting a processing chamber; the second in-line section attached to a second return line entering a coolant source; 16. The valve of claim 15 further comprising:

17. an orifice in the first in-line section into which the plunger is inserted; one or more extension walls surrounding the orifice and attached to an exterior surface of the first in-line section; a bias spring positioned at a first end of the plunger opposite the SMA spring; a backstop attached to the one or more extension walls and in contact with a first end of the bias spring; 17. The valve of claim 16 further comprising:

18. 16. The valve of claim 15, wherein the SMA spring is coupled between an inner wall of the first in-line section and the tip, the SMA spring compressing against the inner wall proportionately in response to exposure to the coolant increasing in temperature above a threshold temperature value.

19. 16. The valve of claim 15, wherein a temperature independent default flow rate of the valve when the second inlet orifice is fully closed by the tip is comprised between 3 and 5 gallons per minute and a maximum flow rate of the valve is comprised between 14 and 18 gallons per minute.

20. 16. The valve of claim 15, wherein the SMA spring is constructed from one of nickel titanium (Ni-Ti), nickel titanium iron (Ni-Ti-Fe), or nickel titanium copper (Ni-Ti-Cu).

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