Method and system for precursor recirculation

Abstract

The present disclosure relates to methods and systems for precursor recirculation. In particular, various embodiments of the present technology may provide a reactor, a first vessel having an inlet coupled to the inlet of the reactor, a second vessel having an inlet coupled to the inlet of the reactor, and an exhaust line coupled to the outlet of the reactor, the inlet of the first vessel, and the inlet of the second vessel. The first and second vessels may be configured to receive the vapor through the exhaust line and recondense the vapor into a solid material to be reused during the precursor pulsing step.

Description

Technical Field

[0001] The present disclosure generally relates to methods and systems for semiconductor devices. More specifically, the present disclosure relates to methods and systems for precursor recycling. Background Art

[0002] During a typical ALD process, precursors are pulsed and purged in multiple cycles to deposit a thin film on a substrate such as a wafer. During the purge step, any remaining precursors that did not react with the substrate surface are purged out with an inert gas and removed via an exhaust system. In a conventional system, during the purge step, the remaining precursors are not reused but are dispersed into the atmosphere. Summary of the Invention

[0003] Various embodiments of the present technology can provide a reactor, a first container having an inlet coupled to an inlet of the reactor, a second container having an inlet coupled to an inlet of the reactor, and an exhaust pipeline coupled to an outlet of the reactor, an inlet of the first container, and an inlet of the second container. The first and second containers can be configured to receive vapor through the exhaust pipeline and re - condense the vapor into a solid material for reuse during a precursor pulse step.

[0004] According to one aspect, a system includes: a reactor including an inlet and an outlet; a first container including a first inlet and a first outlet coupled to the inlet of the reactor; a second container including a second inlet and a second outlet coupled to the inlet of the reactor; and an exhaust pipeline coupled to the outlet of the reactor, the first inlet of the first container, and the second inlet of the second container; wherein the first and second containers are configured to receive vapor through the exhaust pipeline and re - condense the vapor into a solid material. Brief Description of the Drawings

[0005] A more complete understanding of the present technology can be obtained by reference to the detailed description when considered in conjunction with the following illustrative drawings. In the following drawings, the same reference numerals refer to similar elements and steps in all the drawings.

[0006] Figure 1 A system according to an embodiment of the present technology is representatively shown; and

[0007] Figure 2 is a method for operating a system according to an embodiment of the present technology. Detailed Description

[0008] The present technology can be described in terms of functional block components and various processing steps. Such functional blocks can be implemented by any number of components configured to perform the specified functions and achieve various results. For example, the present technology can employ various containers, reaction chambers, pipes, pumps, valves, and heating elements.

[0009] ReferenceFigure 1 In one example, the exemplary system 100 may include a first container 135, a second container 140, and a reactor 105. In an exemplary embodiment, the reactor 105 may be configured to process a substrate, such as a wafer 115. The reactor 105 may include a susceptor 110 for supporting the wafer, a reaction space 112, and a showerhead 120 positioned above the reaction space 112 and the susceptor 110 and configured to deliver chemicals to the reaction space 112 and the wafer 115.

[0010] The system 100 may also include an exhaust system, which may be partially integrated within the reactor 105 and / or disposed external to the reaction chamber 105. In various embodiments, the system 100 may be configured to recycle precursors from the reactor 105 for reuse during processing steps.

[0011] In an exemplary embodiment, the reactor 105 may include an inlet 125 and an exhaust outlet 130. The first container 135 may be coupled to the inlet 125. For example, the outlet 160 of the first container 135 may be coupled to the inlet 125 via a first conduit 150. Additionally, the second container 140 may be coupled to the inlet 125. For example, the outlet 165 of the second container 140 may be coupled to the inlet 125 via a second conduit 155. The first conduit 150 and the second conduit 155 may be configured to allow vapor to flow from the respective containers 135, 140 to the inlet 125 of the reactor 105. Additionally, the first conduit 150 and the second conduit 155 may be actively heated to a temperature that prevents re-condensation of the vapor from the first container 135 and the second container 140 inside the first conduit 150 and the second conduit 155. For example, the second conduit 135 may be heated by any suitable heating element, such as a heater jacket, a printed heater, convective heating, etc.

[0012] In an exemplary embodiment, the exhaust outlet 130 may be coupled to an inlet 170 of the first container 135 and an inlet 175 of the second container 140. The exhaust outlet 130 may also be in communication with the atmosphere.

[0013] In various embodiments, the exhaust system may further include a pump 197 configured to facilitate pumping vapor or gas out of the reactor 105. The pump 197 may include any device or system suitable for facilitating vapor flow. Additionally, the exhaust system may include a plurality of valves, such as a first valve 180 and a second valve 181. The first valve 180 may be disposed downstream of the exhaust outlet 130, and the pump 197 may be disposed downstream of the first valve 180. The second valve 181 may be disposed downstream of the pump 197.

[0014] In various embodiments, the exhaust system may further include a return conduit 199. The return conduit 199 may be coupled between the pump 197 and the second valve 181. The return conduit 199 may connect the exhaust outlet 130 to the inlets of the first container 135 and the second container 140.

[0015] In an exemplary embodiment, the first container 135 may be configured to contain or otherwise hold a solid material 195 (such as a solid precursor chemical). In various embodiments, the solid precursor may be in the form of a powder. The solid precursor may comprise a Group 2, Group 13, Group 14, or Group 15 element and a transition metal halide or a Group 2, Group 13, Group 14, or Group 15 element and a transition metal organometallic compound, which is solid at room temperature (e.g., 20 - 25 degrees Celsius) and has a melting point above 50 degrees Celsius. In an exemplary embodiment, the solid precursor comprises a molybdenum compound, such as a solid molybdenum halide (e.g., MoCl2 or MoOCl4).

[0016] In the present embodiment, the first container 135 may be formed of a metallic material, such as stainless steel, Hastelloy, aluminum, etc.

[0017] The first container 135 may be configured to be maintained at a first temperature, such as about 20 - 25 degrees Celsius, such that the solid material 195 is also maintained at the first temperature. Additionally, the first container 135 may be configured to sublime the solid material 195. For example, the first container 135 may include a heating device 194, which is configured to heat the first container 135 and the solid material 195 to a temperature at which the solid material 195 sublimes and turns into vapor. The heating device 194 may include any suitable heating system or method that is in direct contact with the outer surface of the first container 135, such as a heater jacket or a heating device, where a heating rod is embedded within the heating device. Alternatively, the heating device 194 may provide indirect heat to the first container 135, for example, by convective heating. In some embodiments, the first container 135 may include a sublimator.

[0018] In various embodiments, the first container 135 may further include a cooling device 190, which is configured to cool the first container 135 from a higher temperature (e.g., greater than 25 degrees Celsius) to the first temperature. The cooling device 190 may be in direct contact with the outer surface of the first container 135 and may include any suitable cooling system or method, such as a cooling coil through which a cooling fluid flows, a cooling gas flows through the coil, a thermoelectric module configured to cool the first container 135, etc.

[0019] Similarly, in various embodiments, the second container 140 can be configured to contain or otherwise hold a solid material 195 (such as a solid precursor chemical). In various embodiments, the solid precursor can be in the form of a powder. The solid precursor can include a Group 2, Group 13, Group 14, or Group 15 element and a transition metal halide or a Group 2, Group 13, Group 14, or Group 15 element and a transition metal organometallic, which is solid at room temperature (e.g., 20 - 25 degrees Celsius) and has a melting point above 50 degrees Celsius. In an exemplary embodiment, the solid precursor includes a molybdenum compound, such as a solid molybdenum halide (e.g., MoCl2 or MoOCl4).

[0020] In this embodiment, the second container 140 can be formed of a metallic material, such as stainless steel, Hastelloy, aluminum, etc.

[0021] The second container 140 can be configured to be maintained at a first temperature, such as about 20 - 25 degrees Celsius, such that the solid material 195 is also maintained at the first temperature. Additionally, the second container 140 can be configured to sublime the solid material 195. For example, the second container 140 can include a heating device 196, which is configured to heat the second container 140 and the solid material 195 to a temperature at which the solid material 195 sublimes and turns into a vapor. The heating device 196 can include any suitable heating system or method that is in direct contact with the outer surface of the first container 135, such as a heater jacket or a heating device, where a heating rod is embedded within the heating device. Alternatively, the heating device 196 provides indirect heat to the second container 140, for example, by convective heating. In some embodiments, the second container 140 can include a sublimator.

[0022] In various embodiments, the second container 140 can further include a cooling device 191, which is configured to cool the second container 140 from a higher temperature (e.g., greater than 25 degrees Celsius) to the first temperature. The cooling device 191 can include any suitable cooling system or method that is in direct contact with the outer surface of the container 140, such as a cooling coil through which a cooling fluid flows, a cooling gas flows through the coil, a thermoelectric module configured to cool the second container 140, etc.

[0023] In various embodiments, the system 100 can further include a plurality of valves, such as a first valve 180, a second valve 181, a third valve 182, a fourth valve 183, and a fifth valve 184. In particular, the plurality of valves can be arranged along the exhaust system flow path. For example, the first valve 180 can be arranged downstream of the exhaust outlet 130, and the second valve 181 can be arranged downstream of the first valve 180. In an exemplary embodiment, a pump 197 can be arranged between the first valve 180 and the second valve 181.

[0024] In various embodiments, system 100 may further include additional valves, such as a sixth valve 156 disposed along the first conduit 150 and a seventh valve 157 disposed along the second conduit 155. The sixth valve 156 and the seventh valve 157 may be operated to pulse vapor from the respective containers into the reactor 105.

[0025] In an exemplary embodiment, the exhaust system may include a feedback portion 187 fluidly coupled to the exhaust outlet 130. For example, the feedback portion may be connected between the pump 197 and the second valve 181 at the junction 199.

[0026] In an exemplary embodiment, the feedback portion 187 may include a second valve 182 and a third valve 183. Additionally, the feedback portion 187 may further include a filter 185. The filter 185 may be configured to remove or otherwise neutralize contaminants in the exhaust vapor. For example, the filter 185 may include a porous filter or any other filter adapted to capture particles or contaminants in the vapor. The filter may be disposed upstream of the fourth valve 183 and the fifth valve 184 and downstream of the third valve 182.

[0027] In various embodiments, the feedback portion 187 of the exhaust system may be connected to the first container 135 and the second container 140. For example, the feedback portion 187 may be coupled to the inlet 170 of the first container 135 and the inlet 175 of the second container 140. The feedback portion 187 may include a junction 198, such as a T-shaped junction, where one leg is coupled to the inlet 170 of the first container 135 and the second leg is coupled to the inlet 175 of the second container 140. The fourth valve 183 may be coupled to one leg (to regulate the flow to the inlet 170 of the first container 135), and the fifth valve 184 may be coupled to the second leg (to regulate the flow to the inlet 175 of the second container 140). The filter 185 may be disposed upstream of the junction 198.

[0028] In various embodiments, system 100 may further include a third container 145 configured to hold or otherwise contain a chemical substance, such as the same chemical substance as in the first container 135 and the second container 140. The third container 145 may be coupled to the second inlets of the first container 135 and the second container 140. When the first container 135 and the second container 140 are nearly or completely depleted of the desired chemical substance, the third container 145 may be used to refill the first container 135 and the second container 140 with the desired chemical substance.

[0029] In various embodiments, the first container 135, the second container 140, and the reactor 105 may be located within a processing area such that the first container 135, the second container 140, and the reactor 105 are all physically located near each other or enclosed within a particular tool or area (i.e., clean room, semiconductor manufacturing area). However, the third container 145 may be located in a non - processing area away from the processing area, such as an area physically below the processing area (i.e., sub - manufacturing area).

[0030] In various embodiments, the system 100 may further include a controller 138 configured to generate and transmit various control signals. For example, the controller 138 may be communicatively coupled to a plurality of valves (e.g., valves 156, 157, 180, 181, 182, 183) and transmit control signals to each valve. The control signals may indicate the operation or state (e.g., open or closed) of the corresponding valve. The controller 138 may also control the operation of the heating devices 194, 196 and the cooling devices 190, 191. The heating devices 194, 196 may be controlled independently of each other. Similarly, the cooling devices 190, 191 may be controlled independently of each other.

[0031] In operation, and with reference to Figure 1 and Figure 2, during processing 200, precursors from the first container 135 can be pulsed (during the pulse step) into the reactor 105 (205). In an exemplary embodiment, only one container is used for processing while the other container is in an idle state and not being processed. During the idle state, the container is not at the processing temperature or subliming the precursor. For example, the idle container is at room temperature or any other temperature that allows the precursor to remain in a solid state. During the pulse step (205), the controller 138 can operate the fifth valve 156 to allow vapor to flow from the first container 135 into the reactor 105. After the pulse step, unused precursors can be purged from the reaction space 112 (during the purge step) (210). During the purge step (215), an inert gas 177 can flow through the showerhead 120 and into the reaction space 112, and as the inert gas 177 flows, the unused precursors can flow out of the reactor 105 and enter the exhaust system together with the inert gas. For example, the pump 197 can be activated and the first valve 180 can be opened. In the case where the unused precursors are recycled, the second valve 181 is closed and the unused precursors flow into the feedback portion 187 of the exhaust system. Since the first container 135 is currently being used for processing, the unused precursors flow into the second container 140. For example, the pump 197 can be on, and the controller 138 can open the first valve 180, close the second valve 181, open the third valve 182, close the fourth valve 183, and open the fifth valve 184. The second container 140 is set at a temperature that allows the vapor precursor to re-condense into a solid state. The system 100 such as the controller 138 and other sensors such as a level sensor (not shown) can monitor the level of the precursor 195 in the first container 135 (220). As long as the precursor in the first container 135 does not drop below a predetermined minimum threshold, the system 100 will continue to use the precursor from the first container 135 for processing. Once the precursor in the first container 135 drops below the minimum threshold, the system 100 will use the precursor in the second container 140 for processing (225). During the purge step (230), the inert gas 177 can flow through the showerhead 120 and into the reaction space 112, and the unused precursors flow through the exhaust system and are transferred into the first container 135, which is now at a temperature below the processing temperature and allows the vapor precursor to re-condense in the first container 135. For example, the pump 197 can be on, and the controller 138 can open the first valve 180, close the second valve, open the third valve 182, open the fourth valve 183, and close the fifth valve 184.

[0032] System 100, such as controller 138 and other sensors (not shown), can monitor the precursor level (240) in the second container 140. As long as the precursor in the second container 140 does not drop below a predetermined minimum threshold, system 100 will continue to use the precursor from the second container 140 for processing. Once the precursor in the second container 140 drops below the minimum threshold, system 100 will use the precursor in the first container 135 for processing (205).

[0033] The above steps can continue in a cyclic manner. Additionally, during processing, the container for receiving the recycled precursor vapor can also be refilled with chemicals from the third container 145.

[0034] When the precursor exhaust flows through the filter 185 to the first container 135 or the second container 140, the filter 185 can remove or neutralize contaminants such as water, organic materials, etc.

[0035] In some cases where precursor recycling is not desired, the exhaust system can facilitate the emission of the vapor stream into the atmosphere. For example, the pump 197 is turned on, the first valve 180 and the second valve 181 are open, and the third valve 182 is closed.

[0036] In the foregoing description, the present technology has been described with reference to specific exemplary embodiments. The specific embodiments shown and described are illustrative of the present technology and its best mode and are not intended to limit the scope of the present technology in any way. In fact, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the methods and systems may not be described in detail. Additionally, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or steps between the various elements. Many alternative or additional functional relationships or physical connections may exist in the actual system.

[0037] The present technology has been described with reference to specific exemplary embodiments. However, various modifications and changes can be made without departing from the scope of the present technology. The specification and the drawings are to be regarded in an illustrative rather than a restrictive manner, and all such modifications are intended to be included within the scope of the present technology. Accordingly, the scope of the present technology should be determined by the described general embodiments and their legal equivalents, rather than solely by the above specific examples. For example, unless otherwise explicitly stated, the steps recited in any method or process embodiment can be executed in any order and are not limited to the explicit order presented in the specific examples. Additionally, the components and / or elements recited in any device embodiment can be assembled in various arrangements or otherwise operably configured to produce substantially the same result as the present technology and are thus not limited to the specific configuration recited in the specific examples.

[0038] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, any benefit, advantage, solution to a problem, or any element that may cause any specific benefit, advantage, or solution to occur or become more pronounced should not be construed as a critical, essential, or necessary feature or component.

[0039] The term "comprising" or any variation thereof is intended to refer to non-exclusive inclusion, such that a process, method, article, composition, or apparatus that comprises a list of elements does not include only those elements but may also include other elements not expressly listed or inherent to such process, method, article, composition, or apparatus. Other combinations and / or modifications of the above-described structures, arrangements, applications, proportions, elements, materials, or components used in the practice of the present technology, in addition to those not specifically recited, may vary or may otherwise be particularly adapted to specific environments, manufacturing specifications, design parameters, or other operational requirements without departing from its general principles.

[0040] The present technology has been described above with reference to exemplary embodiments. However, changes and modifications may be made to the exemplary embodiments without departing from the scope of the present technology. These and other changes or modifications are intended to be included within the scope of the present technology as set forth in the appended claims.

Claims

1. A system, comprising: a reactor, which includes an inlet and an outlet; a first container, which includes a first inlet and a first outlet coupled to the inlet of the reactor; a second container, which includes a second inlet and a second outlet coupled to the inlet of the reactor; and an exhaust system, which is coupled to the outlet of the reactor, the first inlet of the first container, and the second inlet of the second container; wherein, one of the first container and the second container is configured to sublimate a solid precursor therein for processing, and wherein the other of the first container and the second container is maintained in an idle state, the idle state having a temperature that allows unreacted precursor received from the exhaust system to recondense therein.

2. The system according to claim 1, wherein, The exhaust system includes a feedback section that couples the reactor to the first container and the second container.

3. The system according to claim 2, wherein The feedback section includes a junction that includes a first branch coupled to the first container and a second branch coupled to the second container.

4. The system according to claim 3, wherein, A first valve is coupled to the first branch to regulate the flow to the first container, and a second valve is coupled to the second branch to regulate the flow to the second container.

5. The system according to claim 3, wherein, The feedback section includes a filter.

6. The system according to claim 5, wherein, The filter is disposed upstream of the junction.

7. The system according to claim 1, wherein, Each of the first container and the second container includes a heating device and a cooling device.

8. A method, comprising: flowing a precursor from a first container to a reactor for processing; flowing unreacted precursor from the reactor into an exhaust system coupled to the reactor; flowing the unreacted precursor from the exhaust system to a second container; and condensing the unreacted precursor into a solid state in the second container for use as a precursor in future processing.

9. The method according to claim 8, further comprising flowing the unreacted precursor from the reactor into a feedback section of the exhaust system, wherein the feedback section of the exhaust system is coupled between the reactor and the second container.

10. The method according to claim 8, wherein, The first container is in a processing state configured to sublimate a solid precursor into the precursor, and the second container is in an idle state at a temperature that allows the precursor to remain in a solid state.

11. The method according to claim 10, further comprising monitoring a precursor level in the first container.

12. The method according to claim 11 further comprises: In response to the precursor level in the first container being lower than a predetermined minimum threshold, changing the first container from the processing state to the idle state, and changing the second container from the idle state to the processing state.

13. The method according to claim 12, further comprising flowing the precursor from the second container to the reactor for processing.

14. The method according to claim 13, further comprising flowing the unreacted precursor from the reactor into the exhaust system and into the first container.

15. The method according to claim 14, further comprising condensing the unreacted precursor into a solid state in the first container for use as a precursor in future processing.

16. The method according to claim 8, further comprising flowing the unreacted precursor through a filter during flowing the unreacted precursor to the second container.

17. The method according to claim 8, wherein, Flowing the unreacted precursor from the reactor and into the exhaust system includes purging the reactor with an inert gas.

18. A method, comprising: Flow a precursor from a first container to a reactor for processing; Flow the unused precursor from the reactor to a second container; and Condense the unused precursor into a solid state in the second container for use as a precursor in future processing.

19. The method according to claim 18, wherein The first container is in a processing state configured to sublime a solid precursor into the precursor, and the second container is in an idle state at a temperature that allows the precursor to remain in a solid state.

20. The method according to claim 19, further comprising: Monitoring the precursor level in the first container; In response to the precursor level in the first container being lower than a predetermined minimum threshold, changing the first container from the processing state to the idle state and changing the second container from the idle state to the processing state; Flowing the precursor from the second container to the reactor for processing; and Flowing the unused precursor from the reactor to the first container.

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