Gas-phase reactor system including a gas detector

Methods of and systems for performing leak checks of gas-phase reactor systems are disclosed. Exemplary systems include a first exhaust system coupled to a reaction chamber via a first exhaust line, a bypass line coupled to a gas supply unit and to the first exhaust system, a gas detector coupled to the bypass line via a connecting line, a connecting line valve coupled to the connecting line, and a second exhaust system coupled to the connecting line. Methods include using the second exhaust system to exhaust the connecting line to thereby remove residual gas in the connecting line that may otherwise affect the accuracy of the gas detector.

FIELD OF INVENTION

The present disclosure generally relates to gas-phase methods and systems. More particularly, the disclosure relates to gas-phase systems that include leak detection apparatus and to methods of detecting leaks within the system.

BACKGROUND OF THE DISCLOSURE

Gas-phase reactors, such as chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), and the like can be used for a variety of applications, including cleaning, depositing and etching materials on a substrate surface. For example, gas-phase reactors can be used to clean, deposit and/or etch layers on a substrate to form semiconductor devices, flat panel display devices, photovoltaic devices, microelectromechanical systems (MEMS), and the like.

A typical gas-phase reactor system includes a reactor including a reaction chamber, one or more precursor and/or reactant gas sources fluidly coupled to the reaction chamber, one or more carrier and/or purge gas sources fluidly coupled to the reaction chamber, a gas distribution system to deliver gases (e.g., precursor and/or reactant gas(es) and/or carrier or purge gas(es)) to a surface of a substrate, and an exhaust source fluidly coupled to the reaction chamber.

Many gas-phase reactors include a gas supply unit to supply desired gases to the reaction chamber. A gas supply unit can include one or more sources (or connections to sources), which may be solid, liquid, or gas, at standard room temperature and pressure, valves, including shutoff and/or control valves, lines, heaters, coolers, and the like. The gas supply unit can also include a housing that surrounds the one or more sources, lines, valves, heaters, and/or coolers.

For various reasons, including safety, it may be desirable to detect gas leakage within the gas supply unit. For example, during operation of a gas-phase reactor system, a valve failure or failure of a gas supply block, for example, may lead to leakage of gas, which, in turn, can make it difficult to control the gas flow rate, and can lead to process and/or reactor system failure. Accordingly, it is generally desirable to detect gas leakage within a gas supply unit as soon as possible.

FIG. 1illustrates a gas-phase reactor system100that includes a gas supply unit102, a reactor104, an exhaust system106, a gas detector108, and a controller110. System100also includes a gas inlet112, valves114-122, and an exhaust path124.

In the illustrated example, gas supply unit102and reactor104are connected via gas inlet112. Process gas is supplied to reactor104through a gas inlet valve114and gas inlet112. Gas inlet valve114can be a part of gas supply unit102and gas inlet112can include a gas supply apparatus, such as a showerhead or the like. Gas from reactor104is exhausted to exhaust system106via exhaust path124. Exhaust system106can include, for example, a dry pump, a scrubber or the like. Exhaust path124can include exhaust valve116. Exhaust valve116can function to control a pressure in the reactor104by being equipped with a pressure control device, e.g., a butterfly wing plate, and it may be controlled by an exhaust valve control unit (not shown) that communicates with a pressure gauge (not shown) installed at reactor104.

System100also includes a divert or bypass path126. Divert path126is connected to gas supply unit102and exhaust path124, and bypasses gas inlet112, reactor104and valve116. Divert path126is especially useful in ALD-type processes to facilitate keeping a process pressure in reactor104constant during a process, because divert path126can be used to switch a gas flow direction to divert path126from reactor104by adjusting valve movements, without increasing or decreasing the gas flow rate. By keeping the process pressure constant, pressure fluctuation in the gas supply line and reactor104may be minimized and the process may be more stable.

In the illustrated example, divert path126includes a first divert valve120, a second divert valve122and a third divert valve118. When gas is supplied to reactor104, first divert valve120and a third divert valve118are closed. When gas is supplied to divert path126, first divert valve120and third divert valve122are open.

Gas detector108is fluidly coupled to divert path126to check for gas leakage within gas supply unit102. For example, when a valve or a part of an integrated gas supply system block of the gas supply unit fails and outer gas leaks into the gas supply unit102through a failed portion of the integrated gas supply system block, gas detector108may detect the leaking gas and send a signal to controller110, and controller110can cause stoppage of the operation of a portion of the system100(dotted line area ofFIG. 1).

FIG. 2illustrates a leak check method200of a gas-phase reactor system, such as gas-phase reactor system100. Method200includes the steps of loading a substrate within a reactor (step202), leak checking the gas supply unit (step204), determining whether a leak rate is greater than a predetermined value (step206), start substrate processing (step208), stop system operation (step210), and end process and unload substrate (step212).

During step202, a substrate is loaded to the reactor (e.g., reactor104). The substrate may be mounted on, for example, a susceptor or a heating block.

During steps204and206, a leak check of the gas supply unit102is carried out. During step204, all valves of the gas supply unit102are open, and the gas inlet valve114and foremost valves (not illustrated) of gas supply unit102, through which gases, such as precursors, reactants and other process gases flow into gas supply unit102from a gas reservoir or vessel (not shown) are closed. Instead, first divert valve120, second divert valve122and third divert valve118are open. In this case, all portions of gas supply unit102are in fluid communication with divert path126and gas detector108, without being in open fluid communication with gas inlet112and reactor104and gas reservoirs or vessels external to gas supply unit102. During step204, gas detector108detects any residual gas exhausted from gas supply unit102, flowing to divert path126. During step206, if the residual gas contains outer gas, such as N2or O2, originated from the atmosphere, and as a result, the leak rate of the gas is over the set value, gas detector108can send a signal to controller110. If a leak is detected, controller110can be configured to cause stoppage of the operation system100(step210). Steps204and206can be performed during a preprocess step of the substrate, such as a preheating step.

Based on the detection results during step206, a process may be performed (step208). The process may be or include film deposition, etching, ashing, cleaning, or the like. If the detection results exceed the set value, the substrate processing system may stop the operation (step210). In other embodiments, the detection results may be synchronized with an interlock system. In this case, if the detection result is over the set value, the interlock system stops the operation.

At step212, when the process is completed, a substrate is unloaded from the reactor and the next substrate is loaded and steps202-212are repeated. In other words, the leak detection of the gas supply unit102is performed repeatedly after a substrate is loaded within a reaction chamber and before processing the substrate from the reaction chamber.

Leak detection of gas supply unit102using system100and method200may exhibit low accuracy in detecting outer gas due to trapped gas in an area128. Area128may be a gas pipe connecting divert path126and gas detector108. Area128desirably includes minimal residual gas or trapped gas in it for accurate leak detection of gas supply unit102after completing step204and step206. But, due to the subsequent substrate processing step208right after the leak detecting steps204and206, second divert valve122is closed to protect gas detector108from process gas flowing into divert path126, thereby trapping gas in the area128. The trapped gas in area128may obstruct the accurate and precise leak detection during step204and step206before processing the next substrate. In another case, gas from the gas supply unit may be accumulated in area128during steps204and206, and the accumulated gas may make it difficult to detect the outer gas accurately. Accordingly, improved systems and methods for detecting leaks in gas-phase reactor systems are desired.

Any discussion of problems and solutions set forth in this section has been included in this disclosure solely for the purposes of providing a context for the present disclosure, and should not be taken as an admission that any or all of the discussion was known at the time the invention was made.

SUMMARY OF THE DISCLOSURE

Various embodiments of the present disclosure relate to gas-phase reactor systems and methods. While the ways in which various embodiments of the present disclosure address drawbacks of prior methods and systems are discussed in more detail below, in general, exemplary embodiments of the disclosure provide improved systems and methods for detecting gas leaks within a gas-phase reactor system.

In accordance with at least one embodiment of the disclosure, a gas-phase reactor system includes a reactor comprising a reaction chamber; a gas supply unit coupled to the reaction chamber via a gas supply line; a first exhaust system coupled to the reaction chamber via a first exhaust line; a bypass line coupled to the gas supply unit and to the first exhaust system; a gas detector coupled to the bypass line via a connecting line; a connecting line valve coupled to the connecting line; and a second exhaust system coupled to the connecting line. In accordance with exemplary aspects of these embodiments, the bypass line is coupled to the gas supply line. The bypass line can also be coupled to the first exhaust line. In accordance with further aspects, the gas-phase reactor system includes a second exhaust line coupled to the connecting line. A second exhaust line valve can be between the connecting line and the second exhaust system. Further, the second exhaust system can be coupled to a chamber, such as a platform chamber or an outer chamber. The gas detector can detect a flowrate and/or a composition (e.g., nitrogen and/or oxygen content) of a gas. The gas-phase reactor system can also include a controller configured to: cause the gas-phase reactor system to perform a leak test after a substrate has been loaded into the reaction chamber and before the substrate is removed from the reaction chamber, cause the gas-phase reactor system to perform a leak test while heating a substrate to a desired process temperature, perform a leak test during a process cycle, stop flow of gas to the reaction chamber when the gas detector detects a flow rate of gas above a predetermined value, stop operation of the gas-phase reactor system when the gas detector detects a flow rate of gas above a predetermined value, exhaust the connecting line during a substrate process within the reaction chamber, and/or exhaust the connecting line by closing the connecting line valve and opening the second exhaust line valve.

In accordance with at least one other embodiment of the disclosure, a method of using a gas-phase reactor system includes the steps of providing a gas-phase reactor system, such as providing a gas-phase reactor system described herein, exhausting the connecting line, and, using the gas detector, analyzing gas exhausted from the gas-phase reactor system. The gas can be exhausted from the gas supply unit. The method can further include a step of closing a second exhaust line valve between the gas detector and the second exhaust system after the step of exhausting the connecting line and prior to the step of analyzing gas. Additionally or alternatively, the method can include a step of exhausting the bypass line during the step of analyzing. Exemplary methods can include a step of loading a substrate within the reaction chamber, wherein the step of analyzing is performed after the step of loading and before a step of unloading the substrate from within the reaction chamber. Alternatively, the method can include a step of loading a substrate within the reaction chamber, wherein the step of analyzing is performed before the step of loading. During the step of analyzing, gas can be exhausted to the second exhaust system. The gas detector can be used to detect a composition and/or flowrate of a gas. For example, the gas detector can be used to determine whether a gas flow rate is above a predetermined level. In this case, the method can include if the gas flow rate is above the predetermined level, stopping flow of gas to the reaction chamber, if the gas flow rate is above the predetermined level, stopping operation of the gas-phase reactor system, and/or if the gas flow rate is above the predetermined level, engaging an interlock system. The step of analyzing can be performed while heating a substrate to a desired process temperature, during a process cycle, and/or after a substrate has been loaded into the reaction chamber and before the substrate is removed from the reaction chamber.

These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments having reference to the attached figures; the invention not being limited to any particular embodiment(s) disclosed.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present disclosure generally relates to gas-phase reactor systems and methods capable of determining a leak. As set forth in more detail below, exemplary systems and methods described herein can be used to more accurately determine a composition, flow rate, and/or amount of gas leaking from one or more areas or sections of a gas-phase reactor system. Further, the systems and methods described herein may be more efficient in processing substrates and performing leak checks, compared to traditional methods and systems.

In this disclosure, “gas” can include material that is a gas at room temperature and pressure, a vaporized solid and/or a vaporized liquid, and may be constituted by a single gas or a mixture of gases, depending on the context. A gas other than the process gas, i.e., a gas introduced without passing through a gas distribution assembly, such as a showerhead, other gas distribution device, or the like, may be used for, e.g., sealing the reaction space, which includes a seal gas, such as a rare gas. A gas can be a reactant or precursor that takes part in a reaction within a reaction chamber and/or include ambient gas, such as air.

In this disclosure, “line” can refer to a conduit, such as a tube, through which gas flows. A line can include one or more valves, branches, or the like. Exemplary lines as described herein can be formed of stainless steel.

In this disclosure, any two numbers of a variable can constitute a workable range of the variable as the workable range can be determined based on routine work, and any ranges indicated may include or exclude the endpoints. Additionally, any values of variables indicated (regardless of whether they are indicated with “about” or not) may refer to precise values or approximate values and include equivalents, and may refer to average, median, representative, majority, etc. in some embodiments. Further, in this disclosure, the terms “constituted by” and “having” refer independently to “typically or broadly comprising,” “comprising,” “consisting essentially of,” or “consisting of” in some embodiments. In this disclosure, any defined meanings do not necessarily exclude ordinary and customary meanings in some embodiments.

In this disclosure, “continuously” can refer to one or more of without breaking a vacuum, without interruption as a timeline, without any material intervening step, without changing treatment conditions, immediately thereafter, as a next step, or without an intervening discrete physical or chemical structure between two structures other than the two structures in some embodiments.

Turning again to the figures,FIG. 3illustrates a gas-phase reactor system300in accordance with exemplary embodiments of the disclosure. Gas-phase reactor system300includes a reactor302comprising a reaction chamber304, a gas supply unit306, a first exhaust system308, a bypass line310coupled to gas supply unit306and to the first exhaust system308, a gas detector312, and a second exhaust system314. Gas-phase reactor system300can also include a controller316to control various portions or devices of gas-phase reactor system300.

Reactor302can include any suitable gas-phase reactor. By way of examples, reactor302can be configured as a chemical vapor deposition reactor, an atomic layer deposition reactor, an etch reactor, a clean reactor, an epitaxial reactor, or the like. In some cases, reactor302can include a direct plasma configuration and/or gas-phase reactor system300can include a remote plasma unit coupled to reactor302. Reactor302includes a gas inlet318to receive gas from gas supply unit306.

Gas supply unit306supplies one or more process gases, such as one or more precursors and/or one or more reactants to reaction chamber304through gas inlet318. Gas supply unit306can also provide a carrier and/or inert gas to the reaction chamber through gas inlet318. Gas supply unit306can include an integrated gas supply block. The integrated gas block system is a block-typed or Lego-typed gas supply system, so as to make the whole gas supply path from the foremost valve to the hindmost valve simple, compact and short, and reduce the blind spots between gas supply path and a valve, compared to conventional plumbing-typed gas supply systems. So the gas supply or switching between gases may be faster in the integrated gas block system than in the conventional plumbing system.

First exhaust system308and second exhaust system314can include any suitable device to exhaust a line and/or reaction chamber. By way of examples, first exhaust system308and/or second exhaust system314can be or include a dry pump, a scrubber, a turbomolecular pump, or the like. As illustrated inFIG. 3, second exhaust system314can be coupled to another chamber320, such as a platform chamber for transferring substrates between a reactor and a cooler or load-lock, or an outer chamber with a rotation arm encompassing multiple reactors in a multi-reactor chamber.

A line338can connect reactor302to first exhaust system308. As illustrated, line338can include a valve340, which can be coupled to and controlled by controller316.

Bypass line310is coupled to gas supply unit306and to first exhaust system308. Bypass line310includes a first bypass line valve322between gas supply unit306and first exhaust system308. Bypass line310can additionally or alternatively include a second bypass line valve324. First and second bypass line valves322and324can include any suitable type valve, such as a pneumatic valve. First and second bypass line valves322and/or324can be coupled to and controlled by controller316.

Gas detector312can detect or measure a flowrate and/or composition of a gas. By way of examples, gas detector312can be or include, for example, SPOES (Self-Plasma Optical Emission Spectroscopy) which decomposes gas, analyzes and detects a type of gas. For example, since nitrogen takes up about 70% of the atmosphere, gas detector312may be configured to detect nitrogen in a gas. In some cases, if the nitrogen is detected by gas detector312, and the detected nitrogen is over the set value, it may be determined that an outer gas (e.g., from an environment surrounding gas supply unit306) has leaked into gas supply unit306and/or elsewhere within gas-phase reactor system300. Additionally or alternatively, gas detector312can include a flow meter and/or a mass flow meter to determine an amount or a flowrate of a leak.

A connecting line330can connect bypass line310to gas detector312. Connecting line330can include a connecting line valve332, which can be a pneumatic valve and which can be coupled to controller316.

Controller316can be any suitable controller that can cause various steps or functions as described herein to be performed. In accordance with various examples of the disclosure, controller316receives signals from gas detector312that can indicate a composition, flowrate, and/or amount of gas. As discussed in more detail below, controller316can be configured to cause one or more of: cause the gas-phase reactor system to perform a leak test after a substrate has been loaded into the reaction chamber and before the substrate is removed from the reaction chamber, cause the gas-phase reactor system to perform a leak test while heating a substrate to a desired process temperature, perform a leak test during a process cycle, stop flow of gas to the reaction chamber when the gas detector detects a flow rate of gas above a predetermined value, stop operation of the gas-phase reactor system when the gas detector detects a flow rate of gas above a predetermined value, exhaust the connecting line during a substrate process within the reaction chamber, and exhaust the connecting line by closing connecting line valve332and opening a second exhaust line valve336based on one or more signals received from gas detector312.

Gas supply unit306and reactor302are connected via gas inlet318. Process gas can be supplied to reactor302through a gas inlet valve326in a gas inlet line328. Although separately illustrated, gas inlet valve326can be a part of gas supply unit306. Gas inlet318can include a gas supply apparatus, such as showerhead or the like.

As illustrated, gas-phase reactor system300can include a second exhaust line334coupled to connecting line330. Second exhaust line334can also be coupled to second exhaust system314. Second exhaust line334can include second exhaust line valve336, which can be a pneumatic valve or the same or similar to a check valve through which gas flows forward, not flowing back, and which can be coupled to and controlled by controller316.

As set forth in more detail below, use of gas-phase reactor system300has several advantages over use of conventional gas-phase reactor systems. For example, while processing a substrate using gas-phase reactor system300, during a substrate processing (e.g., deposition, etch, or clean step), connecting line valve332can be closed (e.g., using controller316) and second exhaust line valve336can be open (e.g., opened using controller316), such that residual gas trapped or accumulated gas in an area (i.e., blind spot)342may be exhausted to second exhaust system314through second exhaust line334. In other words, by adopting this system, any gas that would otherwise be trapped in connecting line330can be mitigated, thereby improving the accuracy of measurements performed using gas detector312. Further, process gas can include compounds that are generated by the reaction between process gases in areas between reaction chamber304and first exhaust system308; these compounds can be deposited and stuck in first exhaust system308. This may make switching between exhaust of gas in bypass line310, coupled to gas supply unit306and to first exhaust system308, and line338coupled between reaction chamber304and first exhaust system308, to first exhaust system308not be smooth. However, using system300, second exhaust line334and the second exhaust system314can be used mitigate abrupt transition to first exhaust system308and thereby provide for more accurate analysis and detection of, for example, outer gas leaked into the gas supply unit306and other gas leaks within gas-phase reactor system300. Further, outgassing effect from the chemical compounds deposited on the inside wall of line338can obstruct the smooth exhaust from bypass line310. This effect is especially severe in processes that generate a lot of by-products such as powder, for example, SiN process using DCS(dichlorosilane) and NH3as process gas, and lower the accuracy of the analysis of leaked gas into the gas supply unit306because of the residual gas in the bypass line310. So it's necessary to remove residual gas in the bypass line310for accurate analysis of leaked gas into the gas supply unit306.

FIGS. 4-7 and 10illustrate gas-phase reactor system300during processing in accordance with additional embodiments of the disclosure.FIGS. 4 and 5illustrate gas-phase reactor system300while performing a leak check after loading a substrate within a reaction chamber (e.g., reaction chamber304) and prior to processing the substrate (e.g., prior to introducing reaction gases into reaction chamber304).FIGS. 6 and 7illustrate another example of gas-phase reactor system300while performing a leak check step after loading a substrate and before processing the substrate. And,FIG. 10illustrates yet another example of gas-phase reactor system300while performing a leak check step.

As illustrated inFIG. 4, after a substrate is loaded within reaction chamber304, first bypass line valve322, second bypass line valve324and second exhaust line valve336are initially open or can be opened using controller316. Gas inlet valve326is initially closed or can be closed using controller316. Connecting line valve332is closed for certain period of time, e.g., less than 10 seconds, e.g., using controller316, so as to remove any potential residual gas area342between a connecting line valve332and a gas detector312.

Next, as illustrated inFIG. 5, first bypass line valve322, connecting line valve332and second bypass line valve324are open (e.g., by opening using controller316). Gas inlet valve326is closed (e.g., using controller316). Second exhaust line valve336is closed for certain period of time, e.g., less than 5 seconds—e.g., using controller316. Next, gas detector312starts detecting and analyzing gas exhausted from the gas supply unit306and/or elsewhere in gas-phase reactor system300.

As illustrated inFIG. 6, in accordance with another embodiment of the disclosure, after a substrate is loaded within reaction chamber304, first bypass line valve322, second bypass line valve324and second exhaust line valve336are open or can be opened using, for example, controller316. Gas inlet valve326is closed or can be closed using, for example, controller316. Connecting line valve332is closed for certain period of time, e.g., less than 10 or 5 seconds, using, e.g., controller316, so as to remove any potential residual gas from the area342between connecting line valve332and gas detector312.

Next, as illustrated inFIG. 7, first bypass line valve322, connecting line valve332and second exhaust line valve336are open or are opened—e.g., using controller316. Gas inlet valve326is closed—e.g., using controller316. Second bypass line valve324is closed, e.g., using controller316, for certain period of time, e.g., less than 10 or 5 seconds. Gas detector312then starts detecting and analyzing gas exhausted from the gas supply unit306. In this embodiment, gas exhausted from gas supply unit306is exhausted to second exhaust system314, so that any blocking effect from first exhaust system308and/or a first exhaust path (e.g., line338) can be avoided. This procedure may be particularly useful in processes capable of producing a lot of byproducts, such as powder, e.g., silicon nitride deposition processes that use DCS and NH3as process gases.

In accordance with illustrative examples, during processing of a substrate, connecting line valve332is closed and second exhaust line valve336is opened (e.g., using controller316) to prevent or mitigate any residual gas from being detected during processing a substrate.

FIG. 10illustrates another example, in which bypass line valve322, connecting line valve332, second bypass line valve324, and second exhaust line valve336are open in a leak check step. In this case, gas can be evacuated from line342as described above by closing connecting line valve332certain period of time, e.g., less than 10 or 5 seconds, using, e.g., controller316, so as to remove any potential residual gas from the area342between connecting line valve332and gas detector312. Then, bypass line valve322, connecting line valve332, second bypass line valve324and second exhaust line valve336are open or can be opened—e.g., using controller316—during a leak check, such that gas is exhausted to both first exhaust system308and second exhaust system314during the leak check. Valve340can be open during this step. This example can be performed before or after processing a substrate.

FIG. 8illustrates leak check results using the gas-phase reactor system illustrated inFIG. 1.FIG. 8illustrates consolidated graphs, showing nitrogen intensity per each leak rate test of gas supply unit102when multiple substrates (four in the illustrative example) were processed successively. InFIG. 8, the Y-axis is the intensity of nitrogen detected by a gas detector (e.g., gas detector108) at each leak rate test. The X-axis is a substrate process time which includes a leak detecting step. It took about 150 seconds for each substrate to be processed.

As illustrated inFIG. 8, the more the leak rate increases, the greater the nitrogen intensity. But, the nitrogen intensity is not uniform and gradually increases as multiple substrates are successively processed. In addition, the nitrogen intensity is detected during the entire substrate processing time, and a leak detecting step is not distinct from a substrate processing step. This is because the gas detector (e.g., gas detector108) keeps detecting the residual gas in the blind spot area128inFIG. 1during substrate processing step—even though valve122is closed. The trapped residual gas can accumulate in the blind spot area and can affect the detection results of the following substrate. For example, some of the nitrogen intensity of the second substrate may come from that of residual gas trapped in the blind spot area during substrate processing of the first substrate. So the leak detection and analysis of the gas supply unit is not accurate and is unreliable.

In contrast,FIG. 9illustrates the leak check results using gas-phase reactor system300in accordance with examples of the disclosure. Contrary to the results illustrated inFIG. 8,FIG. 9illustrates a leak detecting step is clearly distinct from a substrate processing step. A nitrogen intensity is uniform regardless of the number of processed substrates. This is thought to be because residual gas in the blind spot area342is exhausted to the second exhaust system314through a second divert path before the leak detecting step begins.

Therefore, according to examples of the disclosure, a set (e.g., intensity, flowrate, or the like) value may be made. If a measured value (e.g., intensity, flowrate, or the like) is over the set value, an interlock system may be used to stop the operation of system300. As mentioned above, during processing a substrate at the substrate processing step, connecting line valve332is closed and second exhaust line valve336is open to prevent any residual gas from being detected during processing a substrate.

The introduction of second exhaust line334, as described herein, removes residual gas trapped between a second divert valve and a gas detector, and provides more accurate, more reliable leak detection and analysis results of the gas supply unit. In addition, methods as described herein that provide a leak check of the gas supply unit before processing a substrate may prevent potential damage to the substrate by being synchronized with an interlock system. Further, a detection may be performed during a preheating step of the substrate, so the detection does not affect the through-put.

The example embodiments of the disclosure described above do not limit the scope of the invention, since these embodiments are merely examples of the embodiments of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the disclosure, in addition to those shown and described herein, such as alternative useful combinations of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims.