Systems and techniques for gas delivery for semiconductor processing

Abstract

In some embodiments, a system is provided. The system may have a multi-station processing chamber having a first processing station having a first gas distributor and a second processing station having a second gas distributor, a first accumulator configured to contain a first process gas pressurized above a pressure in the chamber, a first flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor, a first fast-acting valve along the first flow path configured to control the first gas flow along the first flow path and configured to open and close in 75 milliseconds or less, a second flow path spanning between, and fluidically connecting, the first accumulator and the second gas distributor, and a second fast-acting valve along the second flow path configured to control gas flow along the second flow path and configured to open and close in 75 milliseconds or less.

Description

SYSTEMS AND TECHNIQUES FOR GAS DELIVERY FOR SEMICONDUCTOR PROCESSINGINCORPORATION BY REFERENCE

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.BACKGROUND

[0002] Semiconductor manufacturing typically involves one or more processing operations to deposit and / or etch a structure on or in a semiconductor wafer (or substrate). Such processes may employ one or more gas delivery systems in which vapor-phase and sometimes gas precursors are reacted with and / or on a surface of a substrate to deposit material thereon or to remove material therefrom. Various gases are used during the one or more processing operations, including flowing purge gases during purge operations and flowing gases during precursor delivery. Although many forms of gas delivery systems exist, they are generally configured to provide controlled gas flow and delivery of gases and precursors.

[0003] The background provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent that it is described in this background, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the disclosure.SUMMARY

[0004] Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. The following, non-limiting implementations are considered part of the disclosure; other implementations will be evident from the entirety of this disclosure and the accompanying drawings as well.

[0005] In some embodiments, a system is provided. The system may have a multi-station processing chamber having a first processing station having a first interior volume and a first gas distributor, and a second processing station having a second interior volume and a secondgas distributor, a first accumulator configured to contain a first process gas pressurized above a pressure in the chamber, a first flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor, a first fast-acting valve along the first flow path that is configured to control the first gas flow along the first flow path and configured to open and close in 75 milliseconds or less, a second flow path spanning between, and fluidically connecting, the first accumulator and the second gas distributor, and a second fast-acting valve along the second flow path configured to control gas flow along the second flow path and configured to open and close in 75 milliseconds or less. When the first fast-acting valve and the second fast-acting valve are both open, the first gas may flow concurrently along the first flow path towards the first gas distributor, and along the second flow path towards the second gas distributor.

[0006] In some embodiments, when the first fast-acting valve and the second fast-acting valve are both closed, the first gas may cease to flow through the fast-acting valve and the second fast-acting valve, may be in the first flow path between the first accumulator and the first fastacting valve, and may be in the second flow path between the first accumulator and the second fast-acting valve.

[0007] In some embodiments, the system may further have a controller having one or more processors and one or more memories that store instructions for controlling the first common accumulator, the first fast-acting valve, and the second fast-acting valve. The instructions may be configured to cause the one or more processors to cause the first process gas to concurrently fill a first upstream portion of the first flow path that spans between the first accumulator and the first fast-acting valve, and a second upstream portion of the second flow path that spans between the first accumulator and the second fast-acting valve, and the first fast-acting valve and the second fast-acting valve to be open at the same time and thereby cause the first gas to flow to the first gas distributor and the second gas distributor at the same time.

[0008] In some such embodiments, the first fast-acting valve and the second fast-acting valve may both closed when the first upstream portion and the second upstream portion are filled with the first gas.

[0009] In some such embodiments, the instructions may be configured to cause the one or more processors to cause the first fast-acting valve and the second fast-acting valve to be open at the same time during an atomic layer deposition processing cycle or atomic layer etching processing cycle, and the first fast-acting valve and the second fast-acting valve to be closed at the end of the purge step.

[0010] In some such embodiments, the instructions may be configured to cause the one or moreprocessors to cause the first fast-acting valve and the second fast-acting valve to repeatedly open and close during an atomic layer deposition processing cycle or atomic layer etching processing cycle, and the first fast-acting valve and the second fast-acting valve to be closed at the end of the purge step.

[0011] In some embodiments, the system may further include a pressure control loop configured to control the pressure in the first accumulator within a first pressure range.

[0012] In some such embodiments, the pressure control loop may be configured to use PID control for controlling the pressure in the first accumulator.

[0013] In some embodiments, the system may further include a second accumulator configured to contain a second process gas pressurized above the pressure in the chamber, a third flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor, a third fast-acting valve along the third flow path that is configured to control the second gas flow along the third flow path and configured to open and close in 75 milliseconds or less, a fourth flow path spanning between, and fluidically connecting, the second accumulator and the second gas distributor, and a fourth fast-acting valve along the fourth flow path that is configured to control gas flow along the fourth flow path and configured to open and close in 75 milliseconds or less. When the third fast-acting valve and the fourth fast-acting valve are both open, the second gas may flow concurrently along the third flow path towards the first gas distributor and along the fourth flow path towards the second gas distributor.

[0014] In some embodiments, the first gas may be argon or hydrogen.

[0015] In any of the above embodiments, there may be no mass flow controllers (MFCs) along the first flow path and the second flow path.

[0016] In any of the above embodiments, the first accumulator may not be an ampoule.

[0017] In any of the above embodiments, the first flow path may include a first flow restrictor fluidically interposed between the first fast-acting valve and the first gas distributor, and the second flow path may include a second flow restrictor fluidically interposed between the second fast-acting valve and the second gas distributor.

[0018] In some embodiments, a method for semiconductor processing is provided. The method may include providing a multi-station processing chamber having a first processing station having a first interior volume and a first gas distributor, a second processing station having a second interior volume and a second gas distributor, a first accumulator containing a first process gas, a first flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor, and a second flow path spanning between, and fluidically connecting, the first accumulator and the second gas distributor, maintaining apressure of the first accumulator above a pressure in the chamber, charging a first portion of the first flow path and a second portion of the second flow path with the first process gas at the pressure. A first fast-acting valve may be positioned along the first flow path, may be configured to control the first gas flow along the first flow path, and may be configured to open and close in 75 milliseconds or less, the first portion may span between the first accumulator and the first fast-acting valve, a second fast-acting valve may be positioned along the second flow path, may be configured to control the first gas flow along the second flow path, and may be configured to open and close in 75 milliseconds or less, and the second portion may spans between the first accumulator and the second fast-acting valve. The method further includes flowing the first gas along the first flow path towards the first gas distributor and along the second flow path towards the second gas distributor at the same time by having the first fastacting valve and the second fast-acting valve both at the same time.

[0019] In some embodiments, the method may further include opening the first fast-acting valve before or at the beginning of a purge step of an atomic layer deposition processing cycle or atomic layer etching processing cycle, opening the second fast-acting valve before or at the beginning of the purge step, closing the first fast-acting valve during or at the end of the purge step, and closing the second fast-acting valve during or at the end of the purge step.

[0020] In some embodiments, the method may further include repeatedly opening and closing the first fast-acting valve during a purge step of an atomic layer deposition processing cycle or atomic layer etching processing cycle, and repeatedly opening and closing the second fastacting valve during the purge step.

[0021] In any of the above embodiments, the maintaining may further include controlling the pressure in the first accumulator within a first pressure range.

[0022] In some embodiments, the controlling may include using PID control.

[0023] In any of the above embodiments, the maintaining may include the charging the first portion and the charging the second portion.

[0024] In any of the above embodiments, the method may further include adjusting, during the flowing, the pressure to a second pressure.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various embodiments disclosed herein are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements.

[0026] Figure 1 depicts an example semiconductor processing system according to variousembodiments.

[0027] Figure 2 depicts the system of Figure 1 in one configuration, according to various embodiments.

[0028] Figure 3 depicts the system of Figure 2 in another configuration, according to various embodiments.

[0029] Figure 4 depicts example gas flow rates in accordance with various embodiments.

[0030] Figure 5 depicts another example semiconductor processing system according to various embodiments.

[0031] Figure 6 depicts the system of Figure 5 in one configuration, according to various embodiments.

[0032] Figure 7 depicts the system of Figure 6 in another configuration, according to various embodiments.

[0033] Figure 8 depicts the system of Figure 6 in another configuration, according to various embodiments.

[0034] Figure 9 depicts a first example technique according to some embodiments.

[0035] Figure 10 depicts another example technique in accordance with disclosed embodiments.

[0036] Figure 11 schematically illustrates a multi-station processing tool according to some embodiments.DETAILED DESCRIPTION

[0037] In the following description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.

[0038] In this application, the terms “semiconductor wafer,” “wafer,” “substrate,” “wafer substrate” and “partially fabricated integrated circuit” are used interchangeably. One of ordinary skill in the art would understand that the term “partially fabricated integrated circuit” can refer to a silicon wafer during any of many stages of integrated circuit fabrication thereon. A wafer or substrate used in the semiconductor device industry typically has a diameter of 200 mm, or 300 mm, or 450 mm. In addition to semiconductor wafers, other work pieces that may take advantage of the disclosed embodiments include various articles, such as printed circuitboards, magnetic recording media, magnetic recording sensors, mirrors, optical elements, micro-mechanical devices, and the like.Introduction and Context

[0039] Various semiconductor manufacturing processes, such as atomic layer deposition (ALD), atomic layer etching (ALE), chemical vapor deposition (CVD), chemical vapor etching (CVE), and the like, as well as plasma-enhanced versions of the same, may employ at least one gas delivery system in which vapor-phase and sometimes gas precursors are reacted with and / or on a surface of a substrate to deposit material thereon or remove material therefrom. Some semiconductor processing performs purge operations during or after performing a processing cycle.

[0040] For example, in ALD processes, precursors are transported to the wafer surface where they are adsorbed by the wafer and then converted by a chemical or physicochemical reaction to form a thin film on the substrate. A plasma may be present in the chamber to facilitate the reaction. ALD processes employ multiple film deposition cycles, each producing a “discrete” film thickness. Multiple “ALD cycles” may be used to build up a film of the desired thickness, and since each layer is thin and conformal, the resulting film substantially conforms to the shape of the underlying devices structure. In certain embodiments, each ALD cycle includes the following steps: (1) exposure of the substrate surface to a first precursor, (2) purge of the reaction chamber in which the substrate is located, (3) activation of a reaction of the substrate surface, optionally by exposure to high temperature and / or a plasma, and / or by exposure to a second precursor, and (4) purge of the reaction chamber in which the substrate is located. The duration of each ALD cycle may be less than 25 seconds or less than 10 seconds or less than 5 seconds. The plasma exposure step (or steps) of the ALD cycle may be of a short duration, such as a duration of 1 second or less, for example. The precursor exposure step may be of similarly short duration.

[0041] In other examples, etching processes often involve exposing a material to be etched to a combination of etching gases to remove the material. ALE is a technique that removes thin layers of material using sequential self-limiting reactions in cycles of nominally self-limiting steps that result in digital and small changes in film thicknesses. In various embodiments, ALE may be performed with plasma, or may be performed thermally. ALE may also be performed in cycles. Generally an ALE cycle is the minimum set of operations used to perform an etch process one time, such as etching a monolayer. The result of one cycle is that at least some of a film layer on a substrate surface is etched. Typically, an ALE cycle includes a modification operation to form a reactive layer, followed by a removal operation to remove or etch only thismodified layer. The cycle may include certain ancillary operations such as sweeping one of the reactants or byproducts, e.g., a purge step. Generally, a cycle contains one instance of a unique sequence of operations. As an example, an ALE cycle may include the following operations: (i) delivery of a reactant gas, (ii) purging of the reactant gas from the chamber, (iii) delivery of a removal gas and an optional plasma, and (iv) purging of the chamber. In some embodiments, etching may be performed nonconformally.

[0042] It is desirable to deliver gases with precise and quick control to each wafer and to each station for multi-station processing chambers. The precise gas control advantageously provides uniform gas delivery to a single wafer, thereby reducing its nonuniformity, and also provides uniform station-to- station gas delivery, thereby reducing stations-to-station variability and nonuniformity. Increasing response time for gas flow controls can also advantageously reduce processing time and increase throughput, while also providing further control precision. Providing these gas flow controls and improvements while also decreasing costs, maintenance, and tool repair time is also desirable.

[0043] Some semiconductor processing tools and systems use mass flow controllers (MFCs) for delivering process gases. In some instances, MFCs may produce variable gas flowrates when delivering gases. For example, the gas flowrate profile from an MFC may begin from zero and then rise to a peak flowrate, followed by an exponential decay. For some semiconductor processing techniques, it may be advantageous to provide a different gas flowrate profile, such as linearly sloped or step-function profiles. These different profiles may be advantageous for controlling and adjusting the precursor gases delivered to a wafer, such as providing a more consistent gas delivery profile.

[0044] Provided herein are new and novel systems, apparatuses, and techniques for providing delivery of process gases to multiple processing stations in one or more processing tools. These systems, apparatuses, and techniques provide for metering and delivering precursor in a controlled and precise way to multiple processing stations while reducing on-wafer nonuniformity, station-to-station nonuniformity, processing times, and costs.Systems for Semiconductor Processing

[0045] According to various embodiments, systems and techniques herein use a common accumulator containing a pressurized process gas that is concurrently delivered to multiple stations via flow paths that each span between the common accumulator and a corresponding station, and that each have a fast-acting valve configured to control the gas flow along the flow path. The pressure in the common accumulator is controlled to provide a desired flow rate, such as a mass flow rate, of the process gas through each flow path to each station. To providefast response and control times, the portion of each flow path between the fast-acting valve and the common accumulator is configured to be charged with the process gas at the same pressure as the common accumulator. This may include providing fluidic connections between those portions and the common accumulator such that these portions and the common accumulator collectively act as a single accumulator.

[0046] In some such embodiments, the fast-acting valves are configured to open and close faster than many other valves, such as opening and closing in less than 75 milliseconds (ms), 50 ms, or 25 ms. Many conventional valves are unable to open and close within this amount of time. Each flow path may also not have a mass flow controller that many other semiconductor processing tools use to control and deliver process gases to one or more stations. As provided above, many MFCs provide a similar gas delivery profile, e.g., a large initial spike followed by an exponential decay, and this profile may not be adjustable, may have limited adjustability, and may not deliver the desired gas delivery characteristics for some processes.

[0047] Figure 1 depicts an example semiconductor processing system according to various embodiments. The system 100 of Figure 1 is a multi-station system having two processing stations, processing station 102A and 102B. Each processing station has a gas distributor 104A and 104B, respectively, that is configured to deliver gases onto a wafer. The gas distributor 104A and 104B of Figure 1 is illustrated as a chandelier-style showerhead, and any type of other gas distributor may be used herein, such as a surface mount chandelier, gas injectors, or other gas distributor configured to deliver gases to the topside or the underside of a wafer. Each processing station 102A and 102B also includes a substrate support 106 A and 106B, respectively, that is configured to support a wafer 108A and 108B, respectively. The substrate supports 106A and 106B may be a pedestal or electrostatic chuck, for example.

[0048] Various aspects of a gas delivery system 110 are also illustrated in Figure 1. A first accumulator 112 is shown which is configured to receive a first process gas from a first process gas source 140 and maintain the process gas at a pressurized state. The first accumulator 112 is fluidically connected to the gas distributor 104 A of processing station 102A via a first flow path 114. The first flow path 114 is shown spanning from a first point 116 at the first accumulator 112 to a second point 118 at the gas distributor 104A. The first flow path 114 also includes a first fast-acting valve 120 that is configured to control the flow of gas along the first flow path 114. As provided above, the first fast-acting valve 120 is configured to open and close in less than about 75 ms, 50 ms, or 25 ms. In some implementations, the first flow path 114 may also have a first flow restrictor 122, such as an orifice, that is fluidically interposed between the first valve 120 and the gas distributor 104A, and that is configured to restrict thegas flow in the first flow path 114. In some embodiments, the first flow restrictor 122 is a configurable orifice that may be manually switched to different orifices.

[0049] The first accumulator 112 is also fluidically connected to the gas distributor 104B of processing station 102B via a second flow path 124. The second flow path 114 is encompassed by a dash-dot-dash shape and shown spanning from the first point 116 at the first accumulator 112 to another point 126 at the gas distributor 104B. The second flow path 124 also includes a second fast-acting valve 128 that is configured to control the flow of gas along the second flow path 124. As provided above, the second fast-acting valve 128 is configured to open and close in less than about 75 ms, 50 ms, or 25 ms. In some implementations, the second flow path 124 may also have a second flow restrictor 130, such as an orifice, that is fluidically interposed between the second fast-acting valve 128 and the gas distributor 104B, and that is configured to restrict the gas flow in the second flow path 124. In some embodiments, the second flow restrictor 130 is a configurable orifice that may be manually switched to different orifices.

[0050] In some implementations, like in Figure 1, the first flow path 114 and second flow path 124 may overlap for a portion 132 near the first accumulator 112. The overlapping portion 132 may span from the first point 116 to a junction point 134 or branch where the two flow paths diverge. Although two stations and two flow paths are shown in Figure 1, the system 100 may have more than two processing stations and each may have a corresponding flow path to the first accumulator like the first and second flow paths 114 and 124.

[0051] The first and second flow paths 114 and 124 receive gas from the first accumulator 112. As mentioned above, the first accumulator 112 is configured to receive gas and maintain it at a pressure which may be a pressure above the pressure of the processing chambers to which it is connected. In some embodiments, the pressure may be above atmospheric pressure. In some other instances, the pressure may be above the pressure of the chambers and below atmospheric pressure. In some instances, the first accumulator 112 may be considered a pressure vessel or pressure volume. The system 100 is configured to control the pressure in the first accumulator 112 to one or more pressures. This control may be through proportional-integral-derivative (PID) control. The system 100 may have one or more pressure sensors 142, or pressure gauges, configured to measure the pressure inside the first accumulator 112 and generate pressure data. The system 100 may also have one or more elements, such as a controller 123, configured to receive the pressure data and control the flow of the first process gas from the source 140 into the first accumulator 112 to control the pressure in the first accumulator 112. In some instances, like in Figure 1, an inlet control valve 144 is configured to control the flow of first process gas from the source 140 into the first accumulator 112. The system 100 may control the inlet controlvalve 144 based on the pressure data from the pressure sensor 142 to control the pressure in the first accumulator 112. In some implementations, the pressure may be maintained at a particular pressure or within a particular pressure range. The pressure may also be increased or decreased to other specific pressures, or to other specific pressure ranges. This control and adjustment may be via PID control, in some embodiments.

[0052] This type of control for the first accumulator may also be considered pressure flow control (“PFC”) of the ampoule. In some instances, PFC is able to control the pressure within the first accumulator by controlling the flow of process gas flow into the ampoule such that the pressure within the first accumulator remains constant. This control may be achieved, for example, by using inlet control valve 144 that can open varying amounts to precisely allow or prevent the flow of process gas into the ampoule.

[0053] In some implementations, the first and second flow paths 114 and 124 are configured to provide the first process gas in the first accumulator 112 concurrently to the gas distributors 104A and 104B. To provide this concurrent gas flow, the system 100 may charge portions of the first and second flow paths 112 and 124 upstream of the first and second fast-acting valves 120 and 128 with the first process gas. For this line charging, the first and second fast-acting valves 120 and 128 are closed. In Figure 1, a first portion of the first flow path 114 that spans from the first fast-acting valve 120 to the first point 116 is charged with gas while the first fastacting valve 120 is closed. A second portion of the second flow path 124 that spans from the second fast-acting valve 128 to the first point 116 is also charged with gas while the second fast-acting valve 128 is closed. These portions may be charged by flowing gas into the first accumulator 112 which flows gas to these portions while the two fast-acting valves are closed which can accumulate pressure in the portions and first accumulator.

[0054] Figure 2 depicts the system of Figure 1 in one configuration, according to various embodiments. Here, the first portion 136 of the first flow path 112 is encircled with a dashed shape. The first portion 136 spans from the first point 116 to the first fast-acting valve 120 which is shown with shading to indicate it is closed. The gas conduits of the first portion 136 are also shown with heavy weight to indicate they are charged with gas that is at a pressure. The second portion 138 of the second flow path 138 is encircled with a dash-dot-dash shape. The second portion 138 spans from the first point 116 to the second fast-acting valve 128 which is shown with shading to indicate it is closed. The gas conduits of the second portion 138 are also shown with heavy weight to indicate they are charged with gas that is at a pressure.

[0055] Due to the fluidic connection with the first accumulator 112, in some instances, the first and second portions 136 and 138 may be charged to the same, or substantially the same (e.g.,within 10% or 5%), pressure as in the first accumulator 112. For example, during some processing operations, the first accumulator 112 and the first and second portions 136 and 138 remain fluidically connected to each other. This continual fluidic connection may result in the first accumulator 112 and the first and second portions 136 and 138 acting as a single plenum. For instance, when the first and second fast-acting valves 120 and 128 are closed, the first accumulator 112 and the first and second portions 136 and 138 remain fluidically connected such that gas flows into, and pressure accumulates in, the first accumulator 112 and these portions. In Figure 2, for example, the first and second portions 136 and 138 and the first accumulator 112 may have the same pressure, Pl, that is above the pressure in the processing stations 102A and 102B. In some instances, the pressure Pl may be above the pressure in the processing stations 102A and 102B and below atmospheric pressure; in some other instances, the pressure may be above atmospheric pressure. In some embodiments, there may be a control valve between the first accumulator 112 and the first and / or second portions 136 and 138. During the operations provided above, this control valve may remain open so the first accumulator 112 and the first and second portions 136 and 138 remain fluidically connected to each other.

[0056] By having the first and second portions 136 and 138 charged with gas at a pressurized state, along with the fast-acting valves, concurrent gas flow to the processing stations 102A and 102B can be controlled quickly, accurately, and with various adjustability. When the first and second fast-acting valves 120 and 128 are open at the same time, the first process gas flows concurrently to the gas distributors 104A and 104B, respectively. Figure 3 depicts the system of Figure 2 in another configuration, according to various embodiments. Here, the first and second fast-acting valves 120 and 128 are in the open position thereby allowing gas to flow through the first and second flow paths to the gas distributors 104A and 104B. When these fastacting valves are open, first process gas can flow through the portions of the flow paths downstream of the fast- acting valves. As mentioned herein, while the first and second fastacting valves 120 and 128 are open, the first accumulator 112 and the first and second portions 136 and 138 remain fluidically connected to each other.

[0057] As can be seen in Figures 1-3, the first process gas is configured to be delivered concurrently to the two process stations 102A and 102B. This configuration includes the sharing of some equipment between the process stations 102A and 102B as well as the elimination of some components found on some other semiconductor processing tools. For example, the two process stations 102A and 102B share the first accumulator 112 and share some portions of the flow conduits between the first accumulator 112 and the process stations102A and 102B, such as the overlapping section 132. The first process gas is also delivered to the process stations 102A and 102B without using MFCs or individual charge volumes corresponding to each process station. By sharing some components and eliminating others, the system 100 described herein provides a cost-effective system that has fewer elements thereby reducing costs and maintenance costs and time.

[0058] As noted above, some implementations have a flow restrictor downstream of each fastacting valve. For example, in Figure 3 the first flow restrictor 122 is downstream of the first fast-acting valve 120 and upstream of the gas distributor 104A, while the second flow restrictor 130 is downstream of the second fast-acting valve 128 and upstream of the gas distributor 104B. The flow restrictor and pressure in the first accumulator 112, which is the pressure of the first process gas in the first and second flow paths 114 and 124, together are configured to control the mass flow of the first process gas to the corresponding gas distributor. The mass flow of the first process gas through the orifice and to the corresponding gas distributor is based, at least in part, on the orifice size and pressure of the first process gas. By using the configurations of the system 100, the size, duration, and flow profile of the first process gas delivered to the processing stations 102A and 102B can be adjusted.

[0059] In some embodiments, the mass flow through the flow restrictors 122 and 130 can be adjusted by changing the pressure in the first accumulator. For example, increasing the pressure in the first accumulator 112 can increase the mass flow of the first process gas through the flow restrictors 122 and 130 and to the gas distributors 104A and 104B, respectively. Similarly, decreasing the pressure in the first accumulator 112 can decrease the mass flow of the first process gas through the flow restrictors 122 and 130 and to the gas distributors 104A and 104B, respectively. This pressure adjustment and corresponding mass flow adjustment can occur quickly and in-situ. For example, a pressure adjustment may occur between or during cycles or ALD or ALE. Adjusting the pressure of the first accumulator 112 to adjust the mass flow rate to both processing stations 102A and 102B is advantageous for multiple reasons including quick response and control time, and adjustability without hardware changes or tool downtime.

[0060] In some implementations, the duration of the gas flow profile can be adjusted by the duration that the fast-acting valves are open. For example, the increasing the duration that the first fast-acting valve 120 and the second fast-acting valve 128 are open increases the duration of the mass flow of the first process gas through the flow restrictors 122 and 130 and to the gas distributors 104A and 104B, respectively. Similarly, the mass flow duration can be decreased by decreasing the duration that the fast-acting valves are open. Although the duration and pressure are discussed separately, both the pressure and duration may be adjusted to furtheradjust the mass flow of the first process gas.

[0061] In some embodiments, the fast-acting valves may be opened and closed rapidly in order to create one or more gas pulses. These gas pulses are configured to shape the flow profile of the first process gas. In some instances, the first process gas may be flowed for about 1 second during a process operation, such as a purge operation, and the fast-acting valves can be opened and closed within 25 ms and 50 ms, for example, which allows the first process gas to be pulsed at least 20 times or more in that 1 second. In some implementations, this pulsed gas flow may be pulse width modulation which may advantageously control the first process gas flow.

[0062] The mass flow profile of the first process gas may also be adjusted and controlled by the refilling of the first accumulator 112. As provided herein, first process gas flowing into the first accumulator 112 increases its pressure which increases its mass flow rate downstream of the fast- acting valves. In some implementations, it may be advantageous to refill the first accumulator after the amount of first process gas has been delivered to the process stations, such as after a process step or operation. For example, the first process gas may be a purge gas, like argon, that is delivered during a purge step of an ALD deposition cycle or ALE etch cycle. The first process gas may be flowed during the purge step, without refilling the first accumulator until after the purge step is complete. This may result in a flow rate the decreases linearly during the purge step or operation. In some other implementations, it may be advantageous to refill the first accumulator during the process step or operation. For example, using PID or other pressure control, the first accumulator may be refilled each time the pressure drops below a particular value which may occur one or more times during a processing step or operations.

[0063] These various flow rates and refills are illustrated in Figure 4 which depicts example gas flow rates in accordance with various embodiments. The vertical axis is unitless gas flow rate and the horizontal axis is unitless time. The three different lines represent three different gas flow profiles of process gas into a process station, like those described above. The legend in the upper right indicates which flow corresponds to which line. The first flow, Flow 1, is a dotted gas flow and this represents gas flow using an MFC. At time Tl, the MFC is actuated and caused to flow gas to the process station. As can be seen, the gas flow has an initial spike of over 10 flow rate units followed by a non-linear decay until time T2 when the MFC flow is stopped.

[0064] The second and third gas flows, Flow 2 and Flow 3, respectively, are exemplary gas flow profiles using the systems and techniques provided herein, including the first accumulator and the fast- acting valves. For example, as noted above, the concurrent gas flow from the firstaccumulator through the two flow paths 114 and 124 and to the processing stations 102A and 102B of Figures 1-3 may occur at relatively uniform flow rates that may linearly decrease. In some instances, this decrease may be due to a pressure drop caused by flowing the gas through the first and second flow paths, and without refilling the first accumulator 112 and thereby without increasing its pressure. Once the concurrent gas flow is stopped by closing the first and second fast-acting valves 120 and 128, the first accumulator 112 may be refilled and repressurized. Various refilling of the first accumulator 112 is illustrated in Figure 4 with Flows 2 and 3.

[0065] Flow 2 of Figure 4 represents gas flow to one of the process stations illustrated in Figure 1-3 using the concurrent flow to both stations described herein. This flow occurs after charging the two portions of the flow paths upstream of the two fast-acting valves, e.g., portions 136 and 138 as illustrated in Figure 2. In Figure 4, these portions are charged before time T1 and at time Tl, the two fast-acting valves are opened and gas flows to the process stations as illustrated in Figure 3. Flow 2 represents gas flow to a single station, e.g., process station 102A. As can be seen, the Flow 2 gas has an initial flow rate which is less than that of the MFC of Flow 1, followed by a linear decline until time T2. During this time period from Tl to T2, the first accumulator 112 is not refilled, or may not be refilled at a rate exceeding the outflow rate to the stations, which results in the pressure in the first accumulator 112 and the two flow paths 114 and 124 to decrease and thereby cause the flow rate to decrease. This type of flow profile of Flow 2 may have various benefits, such as delivering a more uniform and steady flow of gas onto the wafer which can reduce nonuniformity on the wafer, as well as reducing station-to- station nonuniformity.

[0066] For Flow 3 of Figure 4, the gas is again flowed to the process stations by charging the two portions of the flow paths upstream of the two fast-acting valves, e.g., portions 136 and 138 as illustrated in Figure 2, before time Tl, and then opening the two fast- acting valves at time Tl as illustrated in Figure 3. Here, the first accumulator 112 is refilled while the gas is flowing concurrently to the stations between time Tl and time T2. This refilling may occur based on various reasons, such as pressure in the first accumulator 112 dropping below a particular threshold which may be a type of PID control. For example, between time Tl and time to, the flow rate drops while the fast-acting valves are open which results in a pressure drop in the first accumulator 112. At time to, the pressure in the first accumulator has reached the lower threshold and the first accumulator is refilled with the first process gas until time tb when the pressure in the first accumulator reaches the upper threshold. At time tb, the refilling stops and the gas flow continues to the stations. At time to, the pressure in the first accumulatorhas again reached the lower pressure threshold and the first accumulator is refilled until time td when the pressure in the first accumulator has reached the upper threshold and refilling stops. This repeats at times te and time T2 when the gas flow is stopped. This type of flow profile of Flow 3 may have various benefits, such as delivering a more constant flow rate of gas onto the wafer which can reduce nonuniformity on the wafer, as well as reducing station-to- station nonuniformity.

[0067] In some embodiments, the first process gas may be an inert gas, such as argon. In some implementations, the inert gas may be flowed during the purge steps of ALD, ALE, or other processing operations. Because ALD and ALE cycles may be relatively short, such as a duration of less than 25 seconds, 10 seconds, or 5 seconds, the purge steps of each cycle may also be relatively short, such as less than 10 seconds, 5 seconds, or 1 second. In some embodiments, the first process gas may not be inert, e.g., hydrogen, and may be used for nonpurge aspects of processing, such as an activation gas for the activation step ALD or ALE cycles. The systems and techniques provided herein are able to provide for quick gas flow and control during such process operations which can shorten these steps and thereby improve throughput.

[0068] In some embodiments, the gas delivery system may include a second accumulator and corresponding flow paths to the processing stations that are also configured to concurrently flow a second process gas to the processing stations. Eigure 5 depicts another example semiconductor processing system according to various embodiments. Here, the system 500 includes a gas delivery system 510 that has the first accumulator 112, flow paths 114 and 124 and their corresponding components and portions, as well as processing stations 102A and 102B. Bor clarity, the labels for the first and second flow paths 114 and 124 are not shown. The gas delivery system 510 of system 500 further has a second accumulator 550 that is fluidically connected to the gas distributors 104A and 104B of processing stations 102A and 102B, respectively, via a third flow path 552 and a fourth flow path 554. The second accumulator 550 is configured to receive a second process gas from a second gas source 556 and maintain the second process gas at a pressurized state.

[0069] The second accumulator 550 is fluidically connected to the gas distributor 104A of processing station 102A via the third flow path 152. The third flow path 552 is shown spanning from a third point 558 at the second accumulator 550 to the second point 118 at the gas distributor 104A. The third flow path 552 also includes a third fast-acting valve 560 that is configured to control the flow of gas along the third flow path 552. As provided above, the third fast-acting valve 560 is configured to open and close in less than about 75 ms, 50 ms, or25 ms. In some implementations, the third flow path 552 may also have a third flow restrictor 562, such as an orifice, that is fluidically interposed between the third fast-acting valve 560 and the gas distributor 104A, and that is configured to restrict the gas flow in the third flow path 552.

[0070] The second accumulator 550 is also fluidically connected to the gas distributor 104B of processing station 102B via the fourth flow path 554. The fourth flow path 554 is encompassed by a dash-dot-dash shape and shown spanning from the third point 558 at the second accumulator 550 to the other point 126 at the gas distributor 104B. The fourth flow path 554 also includes a fourth fast-acting valve 564 that is configured to control the flow of gas along the fourth flow path 554. As provided above, the fourth fast-acting valve 564 is configured to open and close in less than about 75 ms, 50 ms, or 25 ms. In some implementations, the fourth flow path 554 may also have a fourth flow restrictor 566, such as an orifice, that is fluidically interposed between the fourth fast-acting valve 564 and the gas distributor 104B, and that is configured to restrict the gas flow in the fourth flow path 554. In some implementations, like in Figure 5, the third flow path and fourth flow path may overlap for a portion 568 which is near the second accumulator 550. The overlapping portion 568 may span from the third point 558 to a junction point 570 or branch where the two flow paths diverge. Similar to above, the third and fourth flow restrictors 562 and 566 may also be configurable flow orifices that can be manually changed to differently sized orifices to manually adjust the mass flow through the corresponding flow paths.

[0071] In some embodiments, the second accumulator 550 is configured to operate the same as the first accumulator 112 and described above. For example, the second accumulator 550 is configured to receive the second process gas and maintain it at a pressure above the pressure in the processing stations 102A and 102B. In some instances, the pressure may be above the pressure in the processing stations 102A and 102B and below atmospheric pressure; in some other instances, the pressure may be above atmospheric pressure. The system 500 is configured to control the pressure in the first accumulator 112 to one or more pressures and the pressure in the second accumulator 550 to one or more pressures, which may be the same or different than the first accumulator 112. This control may be through PID control. The system 500 may have one or more pressure sensors 572, or pressure gauges, configured to measure the pressure inside the second accumulator 550 and generate second pressure data. The system 500 may also have one or more elements, such as a controller 523, configured to receive the second pressure data and control the flow of the second process gas from the source 556 into the second accumulator 550 to control the pressure in the second accumulator 550. In some instances, likein Figure 5, a second inlet control valve 574 is configured to control the flow of second process gas from the source 556 into the second accumulator 550. The system 500 may control the second inlet control valve 574 based on the second pressure data from the second pressure sensor 572 to control the pressure in the second accumulator 550. In some implementations, the pressure may be maintained at a particular pressure or within a particular pressure range. The pressure may also be increased or decreased to other specific pressures, or to other specific pressure ranges. This control and adjustment may be via PID control, in some embodiments. This control and adjustment may also be via PFC, described above.

[0072] Similar to the first and second flow paths, in some implementations, the third and fourth flow paths 552 and 554 are configured to provide the second process gas in the second accumulator 550 concurrently to the gas distributors 104A and 104B. To provide this concurrent gas flow, the system 500 may charge portions of the third and fourth flow paths 552 and 554 upstream of the third and fourth fast-acting valves 560 and 564 with the second process gas in the second accumulator 550. For this line charging, the third and fourth fast-acting valves 560 and 564 are closed. In Figure 5, a third portion of the third flow path 552 that spans from the third fast-acting valve 560 to the third point 558 is charged with the second process gas while the third fast-acting valve 560 is closed. A fourth portion of the fourth flow path 554 that spans from the fourth fast-acting valve 564 to the third point 558 is also charged with the second process gas while the fourth fast-acting valve 564 is closed. These portions are charged by flowing gas into the second accumulator 550 which flows the second process gas to these portions while the two fast-acting valves are closed which can accumulate pressure in the portions and first accumulator.

[0073] Figure 6 depicts the system of Figure 5 in one configuration, according to various embodiments. Here, the third portion 576 of the third flow path 554 is encircled with a dash- dot-dash shape. The third portion 578 spans from the third point 558 to the third fast-acting valve 560 which is shown with shading to indicate it is closed. The gas conduits of the third portion 576 are also shown with heavy weight to indicate they are charged with gas that is at a pressure. The fourth portion 578 of the fourth flow path 554 is encircled with a dashed shape. The fourth portion 578 spans from the third point 558 to the fourth fast-acting valve 564 which is shown with shading to indicate it is closed. The gas conduits of the fourth portion 578 are also shown with heavy weight to indicate they are charged with gas that is at a pressure. The system 500 also shows the first and second portions, not labeled, of the first and second flow paths also charged with the first process gas, as illustrated in Figure 2. The system 5 may therefore have these upstream portions of the fourth flow paths concurrently charged with gas.

[0074] Due to the fluidic connection with the second accumulator 550, in some instances, the third and fourth portions 576 and 578 may be charged to the same, or substantially the same (e.g., within 10% or 5%), pressure as in the second accumulator 550. For example, during some processing operations, the second accumulator 550 and the third and fourth portions 576 and 578 remain fluidically connected to each other. This continual fluidic connection may result in the second accumulator 550 and the third and fourth portions 576 and 578 acting as a single plenum during charging and flowing to the stations. For instance, when the third and fourth fast-acting valves 560 and 564 are closed, the second accumulator 550 and the third and fourth portions 576 and 578 remain fluidically connected such that gas flows into, and pressure accumulated in, the second accumulator 550 also flows and accumulates concurrently in these portions. In Figure 5, for example, the third and fourth portions 576 and 578 and the second accumulator 550 may have the same pressure, P2, that is above the pressure in the processing stations 102A and 102B. In some instances, the pressure P2 may be above the pressure in the processing stations 102A and 102B and below atmospheric pressure; in some other instances, the pressure P2 may be above atmospheric pressure. In some embodiments, there may be a control valve between the second accumulator 550 and the third and / or fourth portions 576 and 578. During the operations provided above, this control valve may remain open so the second accumulator 550 and the third and fourth portions 576 and 578 remain fluidically connected to each other.

[0075] By having the third and fourth portions 576 and 578 charged with gas at a pressurized state, along with the fast-acting valves, concurrent gas flow to the processing stations 102A and 102B can be controlled quickly, accurately, and with various adjustability. When the third and fourth fast-acting valves 560 and 564 are open at the same time, the second process gas flows concurrently to the gas distributors 104A and 104B, respectively. Figure 7 depicts the system of Figure 6 in another configuration, according to various embodiments. Here, the third and fourth fast-acting valves 560 and 564 are in the open position thereby allowing the second process gas to flow through the first and second flow paths to the gas distributors 104A and 104B. When these fast-acting valves are open, second process gas can flow through the portions of the flow paths downstream of the fast- acting valves. As mentioned herein, while the third and fourth fast-acting valves 560 and 564 are open, the second accumulator 550 and the third and fourth portions 552 and 554 remain fluidically connected to each other. As further illustrated, the first and second fast-acting valves 120 and 128 remain closed to prevent the first process gas from flowing to the gas distributors 104A and 104B while the second process gas is flowing.

[0076] The first process gas can be flowed by closing the third and fourth fast-acting valves 560 and 564 and opening the first and second fast-acting valves 120 and 128, similar to shown in Figure 3. Figure 8 depicts the system of Figure 6 in another configuration, according to various embodiments. Here, the third and fourth fast-acting valves 560 and 564 are in the closed positions while the first and second fast-acting valves 120 and 128 are in the open positions. This allows the first process gas to flow to the two process stations 102A and 102B, while the second process does not. The third and fourth process stations 576 and 578 remain charged with the second process gas.

[0077] As can be seen in Figures 5-7, the second process gas is configured to be delivered concurrently to the two process stations 102A and 102B. This configuration includes the sharing of some equipment between the process stations 102A and 102B as well as the elimination of some components found on some other semiconductor processing tools. For example, the two process stations 102A and 102B share the first and second accumulators 112 and 550, and share some portions of the flow conduits between the accumulators and the process stations 102A and 102B. The first and second process gases are also delivered to the process stations 102A and 102B without using MFCs or individual accumulators corresponding to each process station. By sharing some components and eliminating others, the system 500 described herein provides a cost-effective system that has fewer elements thereby reducing maintenance costs and time.

[0078] As noted above, some implementations have a flow restrictor downstream of each fastacting valve. For example, in Figure 5 the third flow restrictor 562 is downstream of the third fast-acting valve 560 and upstream of the gas distributor 104A, while the fourth flow restrictor 566 is downstream of the fourth fast-acting valve 564 and upstream of the gas distributor 104B. The flow restrictor and pressure in the second accumulator 550, which is the pressure of the second process gas in the third and fourth flow paths 576 and 578, together are configured to control the mass flow of the second process gas to the corresponding gas distributor. In other words, the mass flow of the second process gas through the orifice and to the corresponding gas distributor is based, at least in part, on the orifice size and pressure of the second process gas. By using the configurations of the system 500, the size, duration, and flow profile of the second process gas delivered to the processing stations 102A and 102B can be adjusted as with the first process gas described above.

[0079] For example, the mass flow through the flow restrictors 562 and 566 can be adjusted by changing the pressure in the second accumulator 550. This may include increasing the pressure in the second accumulator 550 to increase the mass flow of the second process gasthrough the flow restrictors 562 and 566 and to the gas distributors 104A and 104B, respectively, as well as decreasing the pressure in the second accumulator 550 to decrease the mass flow of the second process gas to the gas distributors 104A and 104B. This pressure adjustment and corresponding mass flow adjustment can occur quickly and in-situ.

[0080] In some implementations, the duration of the gas flow profile can be adjusted by the duration that the fast-acting valves are open. For example, the increasing the duration that the third and fourth fast-acting valves 560 and 562 are open increases the duration of the mass flow of the second process gas to the gas distributors 104A and 104B, respectively. Similarly, the mass flow duration can be decreased by decreasing the duration that the fast-acting valves are open. Although the duration and pressure are discussed separately, both the pressure and duration may be adjusted to further adjust the mass flow of the first process gas.

[0081] In some embodiments, like described above, the fast- acting valves may be opened and closed rapidly in order to create one or more gas pulses. These gas pulses are configured to shape the flow profile of the second process gas. In some instances, the second process gas may be flowed for about 1 second during a process operation, such as an activation operation, and the fast-acting valves can be opened and closed within 25 ms and 50 ms, for example, which allows the second process gas to be pulsed at least 20 times or more in that 1 second. In some implementations, this pulsed gas flow may be pulse width modulation which may advantageously control the first process gas flow.

[0082] The mass flow profile of the first process gas may also be adjusted and controlled by the refilling of the second accumulator 550, like described above. For example, the second accumulator 550 may be refilled like Flow 2 and Flow 3 of Figure 3, as well as any other refilling described herein for the first accumulator 112.

[0083] As noted above, the first and second accumulators may be considered pressure vessels, or volumes configured to contain pressurized gas. The first accumulator and second accumulator are not ampoules.Techniques for Semiconductor Processing

[0084] Various techniques are also provided to flow the gas from an accumulator concurrently to multiple stations using fast-acting valves. Figure 9 depicts a first example technique according to some embodiments. The technique may begin by providing a system like shown in Figure 1 and which has at least two processing stations 102A and 102B (e.g., it is a multistation tool), the first accumulator 112, the first flow path 114 fluidically connecting the first accumulator 112 to the gas distributor 104A and having the first fast-acting valve 120, and the second flow path 124 fluidically connecting the first accumulator 112 to the gas distributor104B and having the second fast-acting valve 128. In block 901, the pressure of the first accumulator 112 is maintained at a first pressure which is above the pressure in the processing stations 102A and 102B. In some instances, the first pressure may be above the pressure in the processing stations 102A and 102B and below atmospheric pressure; in some other instances, the first pressure may be above atmospheric pressure. This pressure of the first accumulator 112 may be maintained, controlled, and adjusted as provided herein. In block 903, and referring to Figure 2, the first portion 136 of the first flow path 114 spanning between the first point 116 and the first fast- acting valve 120 may be charged with the first process gas and the second portion 138 of the second flow path 124 spanning between the first point 116 and the second fast- acting valve 128 may be concurrently charged with the first process gas.

[0085] As provided above, the charging of the first and second portions 136 and 138, respectively, occurs at the same time as the pressure in the first accumulator is also pressurized with the first process gas. Accordingly, in some implementations, blocks 901 and 903 may occur at the same time. As also provided above, the first and second fast-acting valves 120 and 128 may be closed during the charging of block 903, and also, in some instances, block 901.

[0086] In block 905, the first process gas is flowed at the same time to the first and second processing stations 102 A and 102B and their gas distributors 104A and 104B, respectively. This concurrent gas flow may be what’s illustrated in Figure 3. In some implementations, the flowing of block 905 may occur for the duration of the time the gas flow is desired. For example, the fast-acting valves may remain open during this time. In some other implementations, the flowing of block 905 may occur repeatedly for the duration of the time the gas flow is desired by repeatedly opening and closing the fast-acting valves which may be considered pulsing the gas flow.

[0087] The concurrent gas flow may occur while both the fast- acting valves 120 and 128 are open. In some instances, the fast-acting valves 120 and 128 may open at the same time and close at the same time which may reduce station-to-station nonuniformity. In some other instances, it may be advantageous to start the gas flow of one station before starting the gas flow to the other station and / or to stop the gas flow of one station before stopping the gas flow to the other station. Due to various inconsistencies or nonuniform components and process conditions, starting and / or stopping the gas flows at different times may advantageously reduce nonuniformity as compared to starting and / or stopping the gas flows at the same time. Given the fast-acting nature of the valves described herein, the different between opening and closing the valves relative to each other can be on the order of milliseconds which may reduce nonuniformity without adversely affecting the pressure in the flow paths. For example, sometechniques may open the first fast-acting valve 120 before opening the second fast-acting valve 128 and they remain open for a duration of time. Some techniques may close the two fastacting valves 120 and 128 at the same time, close the first fast-acting valve 120 before the second fast-acting valve 128, or close the first fast-acting valve 120 after the second fast-acting valve 128. Similarly, some techniques may open the two fast-acting valves 120 and 128 at the same time and close one of them before the other.

[0088] In some embodiments, the fast-acting valves may be opened and closed rapidly to pulse the gas flow which may be considered concurrent gas flow. For example, the fast- acting valves provided herein can open and close in about 25 ms or 50 ms, and when this opening and closing is repeated, the gas flow may be pulsed on this time scale. Over the course of a portion of a process step, or the whole step, this pulsing may have the effect of concurrently flowing the gas to the process stations during the portion of, or entire, process step. This concurrent flowing may be considered the pulse width modulation.

[0089] In some implementations, the first accumulator 112 is refilled as described above and as indicated with optional block 907 of Figure 9. This refilling may occur during and / or after the flowing of the first process gas to the gas distributors 104A and 104B. For example, similar to Flow 2 of Figure 4, the first accumulator 112 may be refilled after the flowing of the gas to the gas distributors 104A and 104B between times T1 and T2. The period of time T1 to time T2 may be the duration of a process step, such as a purge step or activation step. In another example, similar to Flow 3 of Figure 4, the first accumulator 112 may be refilled during the flowing of the gas to the gas distributors 104A and 104B between times T1 and T2.

[0090] The techniques provided herein may be utilized for both the systems of Figures 1-5 as well as 5 to 8. In some implementations, the technique of blocks 901-907 may be used for each accumulator and corresponding flow paths of system 5 in Figures 5-8. Figure 10 depicts another example technique in accordance with disclosed embodiments. Here, the technique includes providing the system 500 of Figure 5 having the first and second accumulators 112 and 550 as well as the four flow paths 114, 124, 552, and 554. In block 1001, the first pressure is maintained in the first accumulator 112 like in block 901, and in block 1003, the second pressure is maintained in the second accumulator 550. In block 1005, the first and second portions 136 and 138 are charged as described above. In blocks 1007, the third portion 576 of the third flow path 552 and the fourth portion 578 of the fourth flow path 554 are charged with the second process gas as illustrated in Figure 6. In some instances, like shown in Figure 6, the first, second, third, and fourth portions 136, 138, 176, and 178 of the four flow paths may all be charged at the same time.

[0091] In block 1009, the first process gas is flowed to the gas distributors 104A and 104B as provided herein and illustrated in Figure 8. During this block 1009, the third and fourth fastacting valves 560 and 564 may be closed while the first and second fast-acting valves 120 and 128 are open. In block 1011, the second gas is flowed to the gas distributors 104A and 104B as provided herein and illustrated in Figure 7. During this block 1011, the third and fourth fastacting valves 560 and 564 may be open while the first and second fast- acting valves 120 and 128 are closed. During or after block 1009, the first accumulator may be refilled and similarly, during or after block 1011, the second accumulator may be refilled.

[0092] The controller, or system controller, provided herein is configured to cause the described systems to perform the operations of these techniques. This includes instructions stored on the one or more memories that are configured to cause one or more processors of the controller to cause the system to execute such functionality. This included opening and closing the fast-acting valves, as well as flowing gas to the first and second accumulators and maintaining their pressures. For example, system 100 includes controller 123 and system 500 includes controller 523. These controllers are configured to control the system and execute the techniques provided herein.Multi-station Processing Tool

[0093] Figure 11 schematically illustrates a multi-station processing tool according to some embodiments.

[0094] In some implementations, multi-station processing tool 1100 can include an inbound load lock 1103 and an outbound load lock 1105, either or both of which may include a plasma source and / or an ultraviolet (UV) source. Robot 1107, at atmospheric pressure, is configured to move wafers from a cassette loaded through pod 1109 into inbound load lock 1103 via an atmospheric port 1111. Wafer 1107 is placed by robot 1107 on pedestal 1113 in inbound load lock 1103, atmospheric port 1111 is closed, and inbound load lock 1103 is pumped down. In instances in which inbound load lock 1103 includes a remote plasma source, wafer 1107 may be exposed to a remote plasma treatment in inbound load lock 1103 prior to being introduced into processing chamber 1115. Further, wafer 1107 may be heated in inbound load lock 1103 to, for example, remove moisture and / or adsorbed gases. Next, chamber transport port 1117 to processing chamber 1115 is opened, and another robot 1119 places wafer 1107 into the reactor on a pedestal of a first station shown in the reactor for processing. While the implementation depicted in Figure 11 includes load locks, it will be appreciated that, in some implementations, direct entry of wafer 1107 into a processing station may be provided.

[0095] As seen in Figure 11, processing chamber 1115 includes four process stations,numbered 1 to 4. Each process station may be considered a process module provided above, such as stations 102A and 102B. Each station has a temperature-controlled pedestal (such as temperature-controlled pedestal 1121 of station 1), and gas line inlets, one or more of which may include a corresponding flow adjuster (such as flow adjuster 151) configured to match (or substantially match) flow conditions (e.g., flow conductance, flow velocity, etc.) to the gas line inlets. It will be appreciated that, in some cases, each process station may have different or multiple purposes. For example, in some embodiments, a process station may be switchable between a chemical vapor deposition (CVD) and PECVD process mode. In another example, deposition operations, e.g., PECVD operations, may be performed in one station, while exposure to UV radiation for UV curing may be performed in another station. In some cases, deposition and UV curing may be performed in the same station. Further, although processing chamber 1115 shown as including four stations, embodiments are not limited thereto. For example, processing chamber 1115 may have any suitable number of stations, such as five or more stations, or three or less stations.

[0096] As previously mentioned, multi- station processing tool 1100 may include a wafer handling system (e.g., robot 1119 including spider forks 1101) for transferring and / or positioning wafers within processing chamber 1115. In some embodiments, the wafer handling system may transfer wafers between various process stations and / or between a process station and a load lock. It is contemplated, however, that any suitable wafer handling system may be employed, such as, for example, wafer carousels, other wafer handling robots, etc. Further, multi-station processing tool 1100 may include (or otherwise be coupled to) a system controller 1123 employed to control process conditions and hardware states of multi-station processing tool 1100. System controller 1123 may include one or more memory devices 1125, one or more mass storage devices 1127, and one or more processors 1129. Each processor 1129 may include a central processing unit (CPU) or computer, analog, and / or digital input / output connections, stepper motor controller boards, etc.

[0097] In some embodiments, system controller 1123 controls each of the activities of multistation processing tool 1100. For instance, system controller 1123 may execute system control software 1131 stored in mass storage device 1127, loaded into memory device 1125, and executed by processor 1129. Alternatively, control logic may be hard coded in system controller 1123. Application specific integrated circuits (ASIC), programmable logic devices (e.g., field-programmable gate arrays (FPGAs)) and / or the like may be used for these purposes. In the following discussion, wherever “software” or “code” is used, functionally comparable hard coded logic may be used in its place. System control software 1131 mayinclude instructions for controlling the timing, mixture of gases, gas flow rates, flow conductance, chamber and / or station pressure, chamber and / or station temperature, wafer temperature, target power levels, RF power levels, substrate pedestal, chuck and / or susceptor position, and other parameters of a particular process performed by multi-station processing tool 1100. Further, system control software 1131 may be configured in any suitable way. For example, various process tool component subroutines or control objects may be written to control operation of the process tool components used to carry out various process tool processes. System control software 1131 may be coded in any suitable computer readable programming language.

[0098] In some embodiments, system control software 1131 may include input / output control (IOC) sequencing instructions for controlling the various parameters described above. Other computer software and / or programs stored on mass storage device 1127 and / or memory device 1125 associated with system controller 1123 may be employed in some embodiments. Examples of programs or sections of programs for this purpose include a substrate positioning program, a process gas control program, a pressure control program, a heater control program, a cooler control program, and a plasma control program.

[0099] A substrate positioning program may include program code for process tool components that are used to load and orientate wafer 1107 on pedestal 1121 and to control the spacing between wafer 1107 and other parts of multi-station processing tool 1100.

[0100] A process gas control program may include code for controlling gas composition (e.g., silicon-containing gases, oxygen-containing gases, nitrogen-containing gases, dilution (or inert) gases, etc.) flow rates, flow conductances, and optionally for flowing gas into one or more process stations prior to deposition to stabilize the pressure in the process station. A pressure control program may include code for controlling the pressure in the process station by regulating, for example, a throttle valve in an exhaust system of the process station or the like.

[0101] A heater control program may include code for controlling current to one or more heating units used to heat a pedestal (e.g., pedestal 1121) and / or a showerhead of processing chamber 1115. Additionally or alternatively, the heater control program may control delivery of a heat transfer gas (such as helium) to a gas distributor, and, thereby, to wafer 1107.

[0102] A cooling control program may include code for controlling a flow rate of conductive cooling fluid through a cooling unit used to extract heat from a pedestal (e.g., pedestal 1121) and / or a showerhead of processing chamber 1115, and, thereby, transfer such thermal energy to, for instance, a waste heat capturing, storage, recycling, and / or disposing system. The flowof the cooling fluid through the cooling unit may also extract heat from wafer 1107.

[0103] A plasma control program may include code for setting RF power levels applied to the process electrodes in one or more process stations in accordance with various embodiments.

[0104] A pressure control program may include code for maintaining pressure in a reaction chamber in accordance with various embodiments.

[0105] In some embodiments, a user interface may be provided in association with system controller 1123. The user interface may include a display screen, graphical software displays of the apparatus and / or process conditions, and user input devices, such as pointing devices, keyboards, touch screens, microphones, etc.

[0106] In some embodiments, parameters adjusted by system controller 1123 may relate to process conditions. Non-limiting examples include process gas composition and flow rates, temperature, pressure, plasma conditions (such as RF bias power levels), pressure, temperature, etc. These parameters may be provided to the user in the form of a recipe, which may be entered utilizing the user interface.

[0107] Signals for monitoring the process may be provided by analog and / or digital input connections of system controller 1123 from various process tool sensors. The signals for controlling the process may be output on analog and / or digital output connections of multistation process tool 1100. Non-limiting examples of process tool sensors that may be monitored include mass flow controllers, pressure sensors (such as manometers), thermocouples, etc. Appropriately programmed feedback and control algorithms may be used with data from the sensors to maintain process conditions.

[0108] System controller 1123 may provide program instructions for implementing one or more of the above-described processes. The program instructions may control a variety of process parameters, such as direct current (DC) power level, RF bias power level, pressure, temperature, etc. The instructions may control the parameters to operate deposition of film stacks of a stress compensation layer according to various embodiments.

[0109] System controller 1123 will typically include one or more memory devices and one or more processors configured to execute the instructions so that the apparatus will perform a method in accordance with some embodiments. In some instances, machine-readable media containing instructions for controlling process operations in accordance with various embodiments may be coupled to system controller 1123.

[0110] In some embodiments, system controller 1123 may be part of a system, which may be part of at least one of the above-described examples. Such systems may include semiconductor processing equipment, including a processing tool or tools, a chamber or chambers, a platformor platforms for processing, and / or specific processing components (e.g., a wafer pedestal, a gas flow system, a thermal management system, etc.). The systems discussed above may be integrated with electronics for controlling their operation before, during, and / or after processing of a semiconductor wafer or substrate. The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. For instance, system controller 1123, depending on the processing requirements and / or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), valve operation, flow adjuster operation, light source control for radiative heating, pressure settings, vacuum settings, power settings, RF generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operational settings, wafer transfers into and out of a tool or chamber and other transfer tools and / or load locks connected to or interfaced with a specific system. In this manner, system controller 1123 may be configured to control, among other systems, the various actuators and motors of a wafer processing system and flow adjusters of a fluid delivery system.

[0111] Broadly speaking, system controller 1123 may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and / or the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to system controller 1123 in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon oxide, surfaces, circuits, dies of a wafer, etc.

[0112] System controller 1123, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, system controller 1123 may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or 1performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g., a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It is to be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus, as described above, system controller 1123 may be distributed, such as by including one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0113] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and / or any other semiconductor processing system that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0114] As noted above, depending on the process step or steps to be performed by the tool, system controller 1123 might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, and / or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.Additional and / or Alternative Embodiments

[0115] Unless otherwise specified, the illustrated embodiments are to be understood as providing example features of varying detail of some embodiments. Thus, unless otherwise specified, the features, components, modules, layers, films, regions, aspects, structures, etc.(hereinafter individually or collectively referred to as an “element” or “elements”), of the various illustrations may be otherwise combined, separated, interchanged, and / or rearranged without departing from the teachings of the disclosure.

[0116] The terminology used herein is for the purpose of describing some embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is to be understood that the phrases “for each <item> of the one or more <items>,” “each <item> of the one or more <items>,” and / or the like, if used herein, are inclusive of both a single-item group and multiple-item groups, i.e., the phrase “for . . . each” is used in the sense that it is used in programming languages to refer to each item of whatever population of items is referenced. For example, if the population of items referenced is a single item, then “each” would refer to only that single item (despite dictionary definitions of “each” frequently defining the term to refer to “every one of two or more things”) and would not imply that there must be at least two of those items. Similarly, the term “set” or “subset” should not be viewed, in itself, as necessarily encompassing a plurality of items — it is to be understood that a set or a subset can encompass only one member or multiple members (unless the context indicates otherwise). The terms “comprises,” “comprising,” “includes,” and / or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and / or provided values that would be recognized by one of ordinary skill in the art. Accordingly, the term “substantially” as used herein, unless otherwise specified, means within 5% of a referenced value. For example, substantially perpendicular means within ±5% of parallel.

[0117] The use of cross-hatching and / or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and / or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and / or descriptive purposes. As such, the sizes and relative sizes of the respective elements are not necessarily limited to the sizes and relative sizes shownin the drawings. When an embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order.

[0118] When an element, such as a layer, is referred to as being “on,” “connected to,” or “coupled to” another element, it may be directly on, directly connected to, or directly coupled to the other element or at least one intervening element may be present. When, however, an element is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element, there are no intervening elements present. Other terms and / or phrases if used herein to describe a relationship between elements should be interpreted in a like fashion, such as “between” versus “directly between,” “adjacent” versus “directly adjacent,” “on” versus “directly on,” etc. Further, the term “connected” may refer to physical, electrical, and / or fluid connection. To this end, for the purposes of this disclosure, the phrase “fluidically connected” is used with respect to volumes, plenums, holes, etc., that may be connected to one another, either directly or via one or more intervening components or volumes, to form a fluidic connection, similar to how the phrase “electrically connected” is used with respect to components that are connected to form an electric connection. The phrase “fluidically interposed,” if used, may be used to refer to a component, volume, plenum, hole, etc., that is fluidically connected with at least two other components, volumes, plenums, holes, etc., such that fluid flowing from one of those other components, volumes, plenums, holes etc., to the other or another of those components, volumes, plenums, holes, etc., would first flow through the “fluidically interposed” component before reaching that other or another of those components, volumes, plenums, holes, etc.. For example, if a pump is fluidically interposed between a reservoir and an outlet, fluid flowing from the reservoir to the outlet would first flow through the pump before reaching the outlet. The phrase "fluidically adjacent," if used, refers to placement of a fluidic element relative to another fluidic element such that no potential structures fluidically are interposed between the two elements that might potentially interrupt fluid flow between the two fluidic elements. For example, in a flow path having a first valve, a second valve, and a third valve arranged sequentially therealong, the first valve would be fluidically adjacent to the second valve, the second valve fluidically adjacent to both the first and third valves, and the third valve fluidically adjacent to the second valve.

[0119] For the purposes of this disclosure, “at least one of X, Y, . . ., and Z” and “at least one selected from the group consisting of X, Y, . . ., and Z” may be construed as X only, Y only, . . ., Z only, or any combination of two or more of X, Y, . . ., and Z, such as, for instance, XYZ,XYY, YZ, and ZZ. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0120] Although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure. To this end, use of such identifiers, e.g., “a first element,” should not be read as suggesting, implicitly or inherently, that there is necessarily another instance, e.g., “a second element.” Further, the use, if any, of ordinal indicators, such as (a), (b), (c), . . ., or (1), (2), (3), . . ., or the like, in this disclosure and accompanying claims, is to be understood as not conveying any particular order or sequence, except to the extent that such an order or sequence is explicitly indicated. For example, if there are three steps labeled (i), (ii), and (iii), it is to be understood that these steps may be performed in any order (or even concurrently, if not otherwise contraindicated), unless indicated otherwise. For example, if step (ii) involves the handling of an element that is created in step (i), then step (ii) may be viewed as happening at some point after step (i). In a similar manner, if step (i) involves the handling of an element that is created in step (ii), the reverse is to be understood.

[0121] Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one element’s spatial relationship to at least one other element as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and / or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” or “over” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly.

[0122] The term “between,” as used herein and when used with a range of values, is to be understood, unless otherwise indicated, as being inclusive of the start and end values of that range. For example, between 1 and 5 is to be understood as inclusive of the numbers 1, 2, 3, 4, and 5, not just the numbers 2, 3, and 4.

[0123] As used herein, the phrase “operatively connected” is to be understood as referring to a state in which two components and / or systems are connected, either directly or indirectly, suchthat, for example, at least one component or system can control the other. For instance, a controller may be described as being operatively connected with (or to) a resistive heating unit, which is inclusive of the controller being connected with a sub-controller of the resistive heating unit that is electrically connected with a relay that is configured to controllably connect or disconnect the resistive heating unit with a power source that is capable of providing an amount of power that is able to power the resistive heating unit so as to generate a desired degree of heating. The controller itself likely will not supply such power directly to the resistive heating unit due to the current(s) involved, but it is to be understood that the controller is nonetheless operatively connected with the resistive heating unit.

[0124] As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the phrases “for each <item> of the one or more <items>,” “each <item> of the one or more <items>,” and / or the like, if used herein, are inclusive of both a single-item group and multiple-item groups, i.e., the phrase “for . . . each” is used in the sense that it is used in programming languages to refer to each item of whatever population of items is referenced. For example, if the population of items referenced is a single item, then “each” would refer to only that single item (despite dictionary definitions of “each” frequently defining the term to refer to “every one of two or more things”) and would not imply that there must be at least two of those items. Similarly, the term “set” or “subset” should not be viewed, in itself, as necessarily encompassing a plurality of items — it is to be understood that a set or a subset can encompass only one member or multiple members (unless the context indicates otherwise). In addition, the terms “comprises,” “comprising,” “includes,” and / or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0125] Various embodiments are described herein with reference to sectional views, isometric views, perspective views, plan views, and / or exploded illustrations that are schematic depictions of idealized embodiments and / or intermediate structures. As such, variations from the shapes of the illustrations as a result of, for example, manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments disclosed herein should not be construed as limited to the particular illustrated shapes of regions, but are to include deviations in shapes that result from, for instance, manufacturing. To this end, regions illustrated in the drawings may be schematic in nature and shapes of these regions may not reflect the actual shapes of regions of a device, and, as such, are not intended to be limiting.

[0126] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and are not to be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

[0127] As customary in the field, some embodiments are described and illustrated in the accompanying drawings in terms of functional blocks, units, and / or modules. Those skilled in the art will appreciate that these blocks, units, and / or modules are physically implemented by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, hard-wired circuits, memory elements, wiring connections, and the like, which may be formed using semiconductor-based fabrication techniques or other manufacturing technologies. In the case of the blocks, units, and / or modules being implemented by microprocessors or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform various functions discussed herein and may optionally be driven by firmware and / or software. It is also contemplated that each block, unit, and / or module may be implemented by dedicated hardware, or as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions. Also, each block, unit, and / or module of some embodiments may be physically separated into two or more interacting and discrete blocks, units, and / or modules without departing from the inventive concepts. Further, the blocks, units, and / or modules of some embodiments may be physically combined into more complex blocks, units, and / or modules without departing from the teachings of the disclosure.

[0128] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and apparatuses of the disclosed embodiments. Accordingly, embodiments are to be considered as illustrative and not as restrictive, and embodiments are not to be limited to the details given herein.

Claims

CLAIMSWhat is claimed is:

1. A system comprising: a multi-station processing chamber comprising: a first processing station having a first interior volume and a first gas distributor, and a second processing station having a second interior volume and a second gas distributor; a first accumulator configured to contain a first process gas pressurized above a pressure in the chamber; a first flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor; a first fast-acting valve along the first flow path that is configured to control the first gas flow along the first flow path and configured to open and close in 75 milliseconds or less; a second flow path spanning between, and fluidically connecting, the first accumulator and the second gas distributor; and a second fast-acting valve along the second flow path configured to control gas flow along the second flow path and configured to open and close in 75 milliseconds or less, wherein when the first fast-acting valve and the second fast-acting valve are both open, the first gas flows concurrently: along the first flow path towards the first gas distributor, and along the second flow path towards the second gas distributor.

2. The system of claim 1, wherein when the first fast-acting valve and the second fast-acting valve are both closed, the first gas: ceases to flow through the fast-acting valve and the second fast-acting valve, is in the first flow path between the first accumulator and the first fast-acting valve, and is in the second flow path between the first accumulator and the second fast-acting valve.

3. The system of claim 1, further comprising a controller having one or more processors and one or more memories that store instructions for controlling the first common accumulator, the first fast-acting valve, and the second fast-acting valve, wherein the instructions are configured to cause the one or more processors to cause:the first process gas to concurrently fill a first upstream portion of the first flow path that spans between the first accumulator and the first fast-acting valve, and a second upstream portion of the second flow path that spans between the first accumulator and the second fastacting valve, and the first fast-acting valve and the second fast-acting valve to be open at the same time and thereby cause the first gas to flow to the first gas distributor and the second gas distributor at the same time.

4. The system of claim 3, wherein the first fast-acting valve and the second fastacting valve are both closed when the first upstream portion and the second upstream portion are filled with the first gas.

5. The system of claim 3, wherein the instructions are configured to cause the one or more processors to cause: the first fast-acting valve and the second fast-acting valve to be open at the same time during an atomic layer deposition processing cycle or atomic layer etching processing cycle, and the first fast-acting valve and the second fast-acting valve to be closed at the end of the purge step.

6. The system of claim 3, wherein the instructions are configured to cause the one or more processors to cause: the first fast-acting valve and the second fast-acting valve to repeatedly open and close during an atomic layer deposition processing cycle or atomic layer etching processing cycle, and the first fast-acting valve and the second fast-acting valve to be closed at the end of the purge step.

7. The system of claim 1, further comprising a pressure control loop configured to control the pressure in the first accumulator within a first pressure range.

8. The system of claim 7, wherein the pressure control loop is configured to use PID control for controlling the pressure in the first accumulator.

9. The system of claim 1, further comprising: a second accumulator configured to contain a second process gas pressurized above the pressure in the chamber; a third flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor; a third fast-acting valve along the third flow path that is configured to control the second gas flow along the third flow path and configured to open and close in 75 milliseconds or less; a fourth flow path spanning between, and fluidically connecting, the second accumulator and the second gas distributor; and a fourth fast-acting valve along the fourth flow path that is configured to control gas flow along the fourth flow path and configured to open and close in 75 milliseconds or less, wherein when the third fast-acting valve and the fourth fast-acting valve are both open, the second gas flows concurrently: along the third flow path towards the first gas distributor, and along the fourth flow path towards the second gas distributor.

10. The system of claim 1, wherein the first gas is argon or hydrogen.

11. The system of any one of claims 1-10, wherein there are no mass flow controllers (MFCs) along the first flow path and the second flow path.

12. The system of any one of claims 1-11, wherein the first accumulator is not an ampoule.

13. The system of any one of claims 1-12, wherein: the first flow path comprises a first flow restrictor fluidically interposed between the first fast-acting valve and the first gas distributor, and the second flow path comprises a second flow restrictor fluidically interposed between the second fast-acting valve and the second gas distributor.

14. A method for semiconductor processing, the method comprising: providing a multi- station processing chamber having a first processing station having a first interior volume and a first gas distributor, a second processing station having a second interior volume and a second gas distributor, a first accumulator containing a first process gas,a first flow path spanning between, and fluidically connecting, the first accumulator and the first gas distributor, and a second flow path spanning between, and fluidically connecting, the first accumulator and the second gas distributor; maintaining a pressure of the first accumulator above a pressure in the chamber; charging a first portion of the first flow path and a second portion of the second flow path with the first process gas at the pressure, wherein a first fast-acting valve is positioned along the first flow path, is configured to control the first gas flow along the first flow path, and is configured to open and close in 75 milliseconds or less, wherein the first portion spans between the first accumulator and the first fast-acting valve, wherein a second fast-acting valve is positioned along the second flow path, is configured to control the first gas flow along the second flow path, and is configured to open and close in 75 milliseconds or less, and wherein the second portion spans between the first accumulator and the second fast-acting valve; and flowing the first gas along the first flow path towards the first gas distributor and along the second flow path towards the second gas distributor at the same time by having the first fast-acting valve and the second fast-acting valve both at the same time.

15. The method of claim 14, further comprising: opening the first fast-acting valve before or at the beginning of a purge step of an atomic layer deposition processing cycle or atomic layer etching processing cycle, opening the second fast-acting valve before or at the beginning of the purge step, closing the first fast-acting valve during or at the end of the purge step, and closing the second fast-acting valve during or at the end of the purge step.

16. The method of claim 14, further comprising: repeatedly opening and closing the first fast-acting valve during a purge step of an atomic layer deposition processing cycle or atomic layer etching processing cycle, and repeatedly opening and closing the second fast-acting valve during the purge step.

17. The method of any one of claims 14 to 16, wherein the maintaining further comprises controlling the pressure in the first accumulator within a first pressure range.

18. The method of claim 17, wherein controlling comprises using PID control.

19. The method of any one of claims 14 to 18, wherein the maintaining comprises the charging the first portion and the charging the second portion.

20. The method of any one of claims 14 to 19, further comprising adjusting, during the flowing, the pressure to a second pressure.

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