System and method for supplying a precursor for an atomic layer deposition (ALD) process

Systems and methods for supplying a precursor material for an atomic layer deposition (ALD) process are provided. A gas supply provides one or more precursor materials to a deposition chamber. The deposition chamber receives the one or more precursor materials via an input line. A gas circulation system is coupled to an output line of the deposition chamber. The gas circulation system includes a gas composition detection system configured to produce an output signal indicating a composition of a gas exiting the deposition chamber through the output line. The gas circulation system also includes a circulation line configured to transport the gas exiting the deposition chamber to the input line. A controller is coupled to the gas supply. The controller controls the providing of the one or more precursor materials by the gas supply based on the output signal of the gas composition detection system.

TECHNICAL FIELD

The technology described in this disclosure relates generally to an atomic layer deposition (ALD) process and more particularly to systems and methods for reducing an amount of precursor material used in an ALD process.

BACKGROUND

Semiconductor processing in the fabrication of integrated circuitry may involve the deposition of layers on semiconductor substrates. Exemplary processes for performing such depositions may include chemical vapor deposition (CVD) processes and atomic layer deposition (ALD) processes, among others. The CVD and ALD processes may be conducted within a deposition chamber that retains one or more substrates upon a wafer holder. In an ALD process, one or more precursor gases may be provided to a showerhead within the deposition chamber, where the showerhead may provide the one or more precursor gases uniformly over an outer surface of the substrate. The one or more precursor gases may react or otherwise cause a layer to be deposited substantially over the substrate. Plasma enhancement may or may not be utilized in the ALD process. If plasma enhancement is utilized, a plasma may be generated and maintained either within the chamber or remote from the chamber.

SUMMARY

The present disclosure is directed to systems and methods for supplying a precursor material for an atomic layer deposition (ALD) process. A system for supplying a precursor material for an ALD process includes a gas supply for providing one or more precursor materials to a deposition chamber. The deposition chamber receives the one or more precursor materials via an input line of the deposition chamber. The system also includes a gas circulation system coupled to an output line of the deposition chamber. The gas circulation system includes a gas composition detection system configured to produce an output signal indicating a composition of a gas exiting the deposition chamber through the output line. The gas circulation system also includes a circulation line configured to transport the gas exiting the deposition chamber to the input line. The circulation line causes the gas exiting the deposition chamber to be transported back into the deposition chamber. The system further includes a controller coupled to the gas supply. The controller controls the providing of the one or more precursor materials by the gas supply based on the output signal of the gas composition detection system.

In another example, a system for supplying a precursor material for an ALD process includes a gas supply for providing one or more precursor materials to a deposition chamber. The system also includes a gas circulation system coupled to an output line of the deposition chamber. The gas circulation system is configured to transport gas exiting the deposition chamber to an input line of the deposition chamber, where the gas circulation system causes the gas exiting the deposition chamber to be transported back into the deposition chamber. The system also includes a filter coupled to the gas circulation system, where the filter reduces contaminants in the gas being transported back into the deposition chamber. The system further includes a gas composition detection system coupled to the output line. The gas composition detection system is configured to produce an output signal indicating a composition of the gas exiting the deposition chamber. A purge gas delivery system is configured to deliver a purge gas to the deposition chamber via a plurality of purge lines. The system also includes a controller coupled to the gas supply, where the controller controls the providing of the one or more precursor materials to the deposition chamber.

In another example, in a method for supplying a precursor material for an ALD process, one or more precursor materials are provided to a deposition chamber. A composition of a gas exiting the deposition chamber is monitored. The gas exiting the deposition chamber is transported back into the deposition chamber via a circulation system. The providing of the one or more precursor materials and the transporting of the gas back into the deposition chamber are controlled based on the monitored composition of the gas exiting the deposition chamber.

DETAILED DESCRIPTION

FIG. 1depicts an example system100for supplying a precursor material for an atomic layer deposition (ALD) process. The example system100ofFIG. 1may include a gas supply102for supplying one or more precursor materials to a deposition chamber104. In one example, the gas supply102may include a plurality of gas canisters, where the plurality of gas canisters may be used to supply different precursor materials used in the ALD process. The gas supply102may supply the one or more precursor materials to the deposition chamber104via an input line106of the deposition chamber. Although the input line106in the example ofFIG. 1is depicted as being open-ended, such that the input line106may be connected to various other external systems (e.g., pump systems, other gas supply systems, etc.), in other examples, the input line106may be connected directly to the gas supply102, such that other external systems may not be connected to the input line106. The gas supply102may supply the one or more precursor materials to the input line106via a supply line103that couples the input line106to the gas supply102.

As described in further detail below with reference toFIG. 3, the deposition chamber104may include a mounting platform or other hardware on which a substrate may be placed. The example system100ofFIG. 1may be used to form one or more deposited layers on the substrate. The deposition chamber104may include an output line110that allows gases and other matter to exit the deposition chamber104. The output line110may include, for example, an exhaust outlet that allows the gases and other matter to exit the deposition chamber104. In some examples, a vacuum pump may be connected to the output line110in order to help evacuate the gases and other matter from the deposition chamber104. Such a vacuum pump may also be utilized to reduce and control a pressure within the deposition chamber104to a desired pressure. The gases and other matter that exit the deposition chamber104may include the one or more precursor materials introduced to the deposition chamber104via the input line106.

A gas circulation system108may be coupled to the output line110of the deposition chamber104. The gas circulation system108may be used to reduce an amount of the one or more precursor materials that are used in the ALD process. For example, in conventional systems that do not utilize the gas circulation system108, the one or more precursor materials may be evacuated from the deposition chamber104via the output line110and directed to an exhaust system (e.g., a typical exhaust system including a filtering system that is exhausted to the atmosphere). Such conventional systems may use a high amount of the one or more precursor materials because a large amount of the precursor materials may be discarded after exiting the deposition chamber104. By contrast, the system100including the gas circulation system108may be used to lower precursor waste in ALD processes and thus also lower production costs.

The gas circulation system108may lower precursor waste by providing a circulation line116that may be coupled between the gas circulation system108and the input line106. The circulation line116may be configured to transport the gas exiting the deposition chamber104to the input line106, which may cause the gas exiting the deposition chamber104to be transported back into the deposition chamber104. In this manner, by circulating precursor gases back into the deposition chamber, rather than directing them to an exhaust system to be discarded, the gas circulation system108may reduce precursor waste in the ALD system100.

In addition to including the circulation line116, the gas circulation system108coupled to the output line110of the deposition chamber104may also include a gas composition detection system112. The gas composition detection system112may be configured to monitor the gas exiting the deposition chamber104and to produce an output signal indicating a composition of the gas. The gas composition detection system112may include one or more different monitoring components, including, for example, a Fourier transform infrared spectroscopy (FTIR) system, a nondispersive infrared sensor (NDIR) system, or a Piezocon gas concentration sensor (PZC) system. Various other types of gas composition monitoring systems may be used in the gas composition detection system112.

The gas circulation system108, and specifically, the gas composition detection system112included therein, may be coupled to a controller118via a connection114(e.g., electrical connection, optical connection, etc.). The controller118may also be coupled to the gas supply102, as illustrated in the example ofFIG. 1. The controller118may control the providing of the one or more precursor materials by the gas supply102to the deposition chamber104. Specifically, the controller118may control the providing of the one or more precursor materials based on the output signal of the gas composition detection system112, where the output signal may be provided to the controller118via the connection114. Thus, for example, the controller118may receive the output signal of the gas composition detection system112, where the output signal may indicate that a particular precursor material is not of an adequate amount in the gas exiting the deposition chamber104. Based on this output signal, the controller118may control the gas supply102to cause more of the particular precursor material to enter the deposition chamber104.

In this example, the gas composition detection system112may thus provide a feedback signal to the controller118, such that a composition of the gas in the chamber104may be controlled. In other examples, the gas composition detection system112may not be connected to the controller118, and in such examples, the controller118may be used to control the providing of the precursor materials to the chamber104without a feedback signal. In such systems where the gas composition detection system112is not connected to the controller118, the gas composition detection system112may be used for other purposes. For example, the gas composition detection system112may be used to monitor the composition of the gas exiting the chamber104to determine if the gas should be transported back into the chamber104via the circulation line116.

FIG. 2depicts an example system200for supplying a precursor material to a deposition chamber204for an ALD process, where the example system200may include a gas circulation system208for causing gas exiting the deposition chamber204to be transported back into the deposition chamber204. The example system200ofFIG. 2may include components similar to those included in the example system100ofFIG. 1. For example, the example system200may include a gas supply202for supplying one or more precursor materials to a deposition chamber204via a supply line203. The supply line203may be coupled to an input line206of the deposition chamber204, such that the one or more precursor materials enter the chamber204via the input line206. The deposition chamber204may include suitable hardware for holding a substrate and may also include an output line210that allows gases (e.g., the one or more precursor materials, purge gas, etc.) and other matter to exit the deposition chamber204.

A gas circulation system208may be coupled to the output line210of the deposition chamber204, where the gas circulation system208may be used to reduce an amount of the one or more precursor materials that are used in the ALD process. The gas circulation system208may lower precursor waste by providing a circulation line216that may be coupled between the gas circulation system208and the input line206. The circulation line216may be configured to transport the gas exiting the deposition chamber204to the input line206, which may cause the gas exiting the deposition chamber204to be transported back into the deposition chamber204through the input line206.

The gas circulation system208may also include a gas composition detection system212. The gas composition detection system212may be configured to monitor the gas exiting the deposition chamber204and to produce an output signal indicating a composition of the gas. The gas composition detection system212may be coupled to a controller218via a connection214(e.g., electrical connection, optical connection, etc.). The controller218may also be coupled to the gas supply202and may control the providing of the one or more precursor materials by the gas supply202to the deposition chamber204. The controller218may control the providing of the one or more precursor materials based on the output signal of the gas composition detection system212.

The gas circulation system208may further include a filter230, where the filter230is configured to remove contaminants or particles from the gas exiting the deposition chamber204. The removal of the contaminants or particles from the gas exiting the deposition chamber204by the filter230may occur prior to the transporting of the gas back into the deposition chamber204via the circulation line216. The contaminants or particles removed by the filter230may be stored in the filter230or may be exhausted or otherwise discarded via a line238of the filter230.

In some situations, it may be determined that the filter230is not necessary (e.g., the gas exiting the deposition chamber204is relatively particle-free). This determination may be made, for example, based on a signal produced by the gas composition detection system212. The signal that may determine whether the filter230is necessary or unnecessary may be the output signal indicating the composition of the gas that is provided to the controller218, or the signal may be a different signal generated by the gas composition detection system212. In another example, the determination of whether to use the filter230may be a decision that is made manually by an operator of the system200, or the determination may be made using a different (e.g., external) system or component (not depicted in the example ofFIG. 2).

When the filter230is not to be used in removing the contaminants or particles from the gas exiting the deposition chamber204, a bypass line222may be used. The bypass line222may allow the gas exiting the deposition chamber204to be transported back into the deposition chamber204(i.e., via the circulation line216) without passing through the filter230. The bypass line222may be enabled or disabled. When the bypass line222is enabled, the gas exiting the deposition chamber204may not pass through the filter230, and when the bypass line222is disabled, the gas exiting the deposition chamber204may pass through the filter230.

The bypass line222may be enabled and disabled by controlling valves234and236. For example, when the valve234on the bypass line222is open, and the valve236is closed, the bypass line222may be enabled, such that the filter230is not used in circulating the gas back into the chamber204. By contrast, when the valve234on the bypass line222is closed, and the valve236is open, the bypass line222may be disabled, such that the filter230is used to remove the contaminants or particles prior to circulating the gas back into the chamber204. In another example, both of the valves234and236may be open, thus causing some of the gas exiting the chamber204to be filtered and some of the gas exiting the chamber204to not be filtered.

The controlling of the valves234and236may be based on an output signal produced by the gas composition detection system212. For example, the gas composition detection system212may determine that the gas exiting the deposition chamber204is relatively particle-free and may produce an output signal that causes the valve234to be opened and the valve236to be closed, thus enabling the bypass line222and disabling use of the filter230. Alternatively, the gas composition detection system212may determine that the gas exiting the deposition chamber204requires filtering and may produce an output signal that causes the valve234to be closed and the valve236to be opened, thus disabling the bypass line222and enabling use of the filter230.

The example system200ofFIG. 2may further include a purge gas delivery system232that is coupled to the deposition chamber204. The purge gas delivery system232may be used to deliver a purge gas to the deposition chamber204via one or more purge lines248. The purge gas delivery system232may include a gaseous tank or other facility that provides a purge gas such as argon, nitrogen, xenon, or another non-reactive gas to the deposition chamber204. In one example, a plurality of purge lines248are used to deliver the purge gas to the deposition chamber204. Using the plurality of purge lines248, as opposed to only a single purge line, a purging efficiency may be increased in the example system200.

The delivery of the purge gas from the purge gas delivery system232may be used to maintain cleanliness in the deposition chamber204(e.g., to remove contaminants, particles, and other undesired matter from the deposition chamber204) and to control a flow of gases in the deposition chamber204. The controlling of the flow of gases may be used, for example, to remove precursor materials from the deposition chamber204. For example, in an example ALD process where multiple precursor materials are used, a first precursor material may be introduced in the chamber204for a first amount of time. The purge gas delivery system232may be used to remove the first precursor material from the chamber204prior to an introduction of a second precursor material to the chamber204.

A vacuum pump240may also be included in the example system200to apply a pressure differential to the deposition chamber204to aid in the removal of gases and other matter from the deposition chamber204. Thus, the purge gas provided by the purge gas delivery system232, along with the vacuum pump240, may be used to purge precursor materials and other gases and matter from the deposition chamber204. In one example, the purge gas delivery system232is controlled based on an output signal of the gas composition detection system212. The output signal of the gas composition detection system212that controls the purge gas delivery system232may be, for example, the output signal indicating the composition of the gas exiting the deposition chamber204via the output line210.

FIG. 3depicts an example deposition system300that may be used to form a deposited layer on a substrate or other structure. The deposited layer may be formed in the example system300ofFIG. 3using a deposition process such as atomic layer deposition (ALD). In the system300, a deposition chamber316may receive precursor materials from a gas supply301via a supply line312. The gas supply301may be used to deliver multiple precursor materials to the deposition chamber316and thus may be understood as including multiple different precursor delivery systems. In the example ofFIG. 3, three different precursor materials may be delivered to the deposition chamber316from the gas supply301, and the gas supply301may be understood as including three different precursor delivery systems. The three different precursor delivery systems may work in conjunction with one another to supply the various different precursor materials to the deposition chamber316.

As illustrated inFIG. 3, each precursor delivery system may include a precursor material supplier302, which may be a gas storage tank, canister, or a machine used to generate the precursor material on an as-needed basis (e.g., in one example where ozone is utilized as a precursor material, the precursor material supplier302may include a concentrator or other ozone generator that can generate ozone as needed). Each precursor delivery system may further include a pneumatic valve304and a flow controller306. The flow controller306may be utilized to control the flow of the precursor material to the deposition chamber316and may thereby help to control the pressure within the chamber316. The flow controller306may be, for example, a proportional valve, a modulating valve, a needle valve, a pressure regulator, a mass flow controller, combinations of these, or the like.

In other examples, each precursor delivery system may further include a carrier gas supply, where the carrier gas supply may supply a gas that may be used to help carry the precursor gas to the deposition chamber316. The carrier gas may be an inert gas or other gas that does not react with the precursor material or other materials within the deposition chamber316. For example, the carrier gas may be helium (He), argon (Ar), nitrogen (N2), hydrogen (H2), combinations of these, or the like. In examples where the carrier gas supply is used, the carrier gas may enter the precursor material supplier302(e.g., the precursor canister) and carry the gaseous precursor material towards the deposition chamber316.

The precursor delivery systems included in the gas supply301may be connected to a precursor gas controller308. The precursor delivery systems may, using the precursor material suppliers302, the pneumatic valves304, and the flow controllers306, supply their individual precursor materials to the precursor gas controller308. The precursor gas controller308may connect and isolate the different precursor delivery systems from the deposition chamber316in order to allow delivery of a desired precursor material to the deposition chamber316. The precursor gas controller308may include such devices as valves, flow meters, sensors, and the like to control the delivery rates of each of the precursors. As illustrated inFIG. 3, the precursor gas controller308may be coupled to a controller340, and the precursor gas controller308may be controlled by instructions received from the controller340. The gas supply301may also be coupled to the controller340, and the controller340may control the providing of the precursor materials by the gas supply301by controlling the flow controllers306or other components of the gas supply301.

The precursor gas controller308, upon receiving instructions from the controller340, may open and close valves so as to connect one of the precursor delivery systems to the deposition chamber316and direct a desired precursor material to the chamber316via the supply line312. The supply line312may be coupled to an input line314of the deposition chamber316, such that the deposition chamber316receives the desired precursor material via the input line314. The deposition chamber316may expose the precursor materials to a substrate placed on mounting hardware318included in the deposition chamber316. The deposition chamber316may be any desired shape that may be suitable for dispersing the precursor materials and contacting the precursor materials with the substrate. In one example, the deposition chamber316may have a cylindrical sidewall and a bottom and may be surrounded by a housing made of material that is inert to the various precursor materials (e.g., steel, stainless steel, nickel, aluminum, alloys of these, or other combinations of these).

The deposition chamber316may have an output line320to allow the precursor materials and other gases and matter to exit the deposition chamber316. A vacuum pump344may be connected to the output line320of the deposition chamber316in order to help evacuate the precursor materials and the gases and other matter from the chamber316. The vacuum pump344may be under control of the controller340and may be utilized to reduce and control the pressure within the deposition chamber316to a desired pressure. A main valve342may be opened and closed as needed to allow the vacuum pump344to apply a pressure differential to the deposition chamber316.

The evacuation of the precursor materials and the other gases and matter from the deposition chamber316may also be aided by a purge gas delivery system339. The purge gas delivery system339may deliver a purge gas to the deposition chamber316. The purge gas delivery system339may include a gas canister335or other component that can provide a purge gas such as argon (Ar), nitrogen (N2), or another non-reactive gas to the deposition chamber316. The purge gas delivery system may further include a pneumatic valve336and a flow controller338(e.g., a mass flow controller or another type of controller) and may be controlled by the controller340. The purge gas delivery system339may deliver the purge gas to the deposition chamber316via a plurality of purge lines. By operating the plurality of purge lines simultaneously (e.g., in parallel), a purge efficiency of the purge gas delivery system339may be increased.

A gas circulation system may be coupled to the output line320of the deposition chamber316, where the gas circulation system may be used to reduce an amount of precursor materials that are used in the deposition process. The gas circulation system may lower precursor waste by providing a circulation line328that may be coupled between the output line320and the input line314of the deposition chamber316. The circulation line328may be configured to transport gas exiting the deposition chamber316to the input line314, which may cause the gas exiting the deposition chamber316to be transported back into the deposition chamber316through the input line314.

The circulation line328may include a circulation valve330, where the circulation valve330may be configured to open and close the circulation line328. When the circulation line328is opened by opening the circulation valve330, the gas exiting the deposition chamber316may be transported back into the deposition chamber316. When the circulation line328is closed by closing the circulation valve330, the gas exiting the deposition chamber may not be transported back into the deposition chamber316. When the circulation line328is closed in this manner, the gas exiting the chamber316may be evacuated out of the system300and transported to an exhaust system by way of the vacuum pump344or otherwise forced to exit the system300without being re-circulated through the chamber316.

As noted above, the supply line312may be coupled to the input line314of the deposition chamber316, such that the deposition chamber316may receive precursor materials via the input line314. As depicted inFIG. 3, the supply line312may include a supply valve310, where the supply valve310may be used to open and close the supply line312. The circulation valve330and the supply valve310may be opened and closed to control a composition of a gas entering the deposition chamber316through the input line314.

In one example, the opening and closing of the circulation valve330and the supply valve310may control i) an amount of the gas exiting the deposition chamber316, and ii) an amount of the precursor materials from the gas supply301that are present in the gas entering the deposition chamber316through the input line314. Thus, the circulation valve330and the supply valve310may be opened and closed to control a mixture of gases entering the deposition chamber316through the input line314, where the mixture may include only the precursor materials from the gas supply301, only the gas exiting the deposition chamber316via the output line320, or a combination of the precursor materials from the gas supply301and the gas exiting the deposition chamber316via the output line320.

The gas circulation system may also include a gas composition detection system346. The gas composition detection system346may be configured to monitor the gas exiting the deposition chamber316and to produce an output signal indicating a composition of the gas. The output signal of the gas composition detection system346may be used to determine when gas exiting the deposition chamber316should be circulated back into the chamber316via the circulation line328and when the deposition chamber316should be purged via the purge gas delivery system339. The gas composition detection system346may include one or more different monitoring components, including, for example, a Fourier transform infrared spectroscopy (FTIR) system, a nondispersive infrared sensor (NDIR) system, or a Piezocon gas concentration sensor (PZC) system. Various other types of gas composition monitoring systems may be used in the gas composition detection system346.

The gas composition detection system346may be coupled to the controller340via a connection332(e.g., electrical connection, optical connection, etc.). As described above, the controller340may also be coupled to the gas supply301and the precursor gas controller308. The controller340may control the providing of the precursor materials to the deposition chamber316by controlling the gas supply301or the precursor gas controller308. The controller340may control the gas supply301or the precursor gas controller308based on the output signal from the gas composition detection system346. Further, in another example, the circulation valve330and the supply valve310may be opened and closed based on the output signal from the gas composition detection system346(e.g., to control a mixture of gases entering the chamber316via the input line314, where the mixture may include gases from the gas supply301and the gas exiting the chamber316via the output line320).

The gas circulation system may further include a filter326, where the filter326is configured to remove contaminants or particles from the gas exiting the deposition chamber316. The removal of the contaminants or particles by the filter326may occur prior to the transporting of the gas back into the deposition chamber316via the circulation line328. The contaminants or particles removed by the filter326may be stored in the filter326or may be exhausted or otherwise discarded via a line350of the filter326.

If the filter326is determined to be unnecessary (e.g., where the determination may be made, for example, based on a signal produced by the gas composition detection system346), a bypass line322may be used. The bypass line322may allow the gas exiting the deposition chamber316to be transported back into the deposition chamber316(i.e., via the circulation line328) without passing through the filter326. The bypass line322may be enabled or disabled by controlling valves324and334. For example, when the valve334on the bypass line322is open, and the valve324is closed, the bypass line322may be enabled, such that the filter326is not used in circulating the gas back into the chamber316. By contrast, when the valve334on the bypass line322is closed, and the valve324is open, the bypass line322may be disabled, such that the filter326is used to remove the contaminants or particles prior to circulating the gas back into the chamber316. The controlling of the valves324and334may be based on an output signal produced by the gas composition detection system346. The valves324and334may be, for example, pneumatic valves or other types of valves.

FIG. 4is a flowchart400illustrating an example method for supplying a precursor material for an atomic layer deposition (ALD) process. At402, one or more precursor materials are provided to a deposition chamber. At404, a composition of a gas exiting the deposition chamber is monitored. At406, the gas exiting the deposition chamber is transported back into the deposition chamber via a circulation system. At408, the providing of the one or more precursor materials and the transporting of the gas back into the deposition chamber are controlled based on the monitored composition of the gas exiting the deposition chamber.

This written description uses examples to disclose the disclosure, including the best mode, and also to enable a person skilled in the art to make and use the disclosure. The patentable scope of the disclosure may include other examples. It should be understood that as used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Further, as used in the description herein and throughout the claims that follow, the meaning of “each” does not require “each and every” unless the context clearly dictates otherwise. Finally, as used in the description herein and throughout the claims that follow, the meanings of “and” and “or” include both the conjunctive and disjunctive and may be used interchangeably unless the context expressly dictates otherwise; the phrase “exclusive of” may be used to indicate situations where only the disjunctive meaning may apply.