Substrate container system and method of cleaning substrate container

Abstract

The present disclosure describes substrate containers that can be used to hold or transport substrates, such as semiconductor wafers and microelectronic devices, in a clean environment, and methods of using the substrate containers.

Description

Technical Field

[0001] The present disclosure relates to substrate containers (sometimes referred to as "substrate carriers" or "wafer containers") that can be used to hold or transport "substrates" (eg, semiconductor wafers or the like) in a clean environment, and methods of using the same. Background Art

[0002] Microelectronic devices are fabricated on semiconductor substrates through a series of precise processing steps, each of which is performed under very clean conditions. Between processing steps, the "substrate" on which the microelectronic devices are formed can be moved from one processing location to a different processing location.

[0003] To move substrates between processing steps or separate processing locations, the substrates are held in specialized containers that are designed to prevent the substrates from being damaged while also shielding them from contamination. Example substrate containers may be referred to as "SMIF pods" (Standard Mechanical Interface Pods), "FOUPs" (Front Opening Unified Pods), or "FOSBs" (Front Opening Shipping Boxes). During use, these containers enclose a space to hold multiple semiconductor wafers or other substrates in an atmosphere that may be evacuated (i.e., under reduced pressure) or may contain a gas different from air (e.g., an inert gas).

[0004] The substrate container may be in the form of a multi-sided container body (e.g., a "shell") defining a container interior. The container body includes an opening on one side that allows multiple substrates to be inserted into or removed from the interior. The container also includes a removable door adapted to cover the opening to enclose the interior with an airtight seal. One or more gas ports (inlet or outlet) pass through the body of the container to allow gas to be introduced into the interior to control the atmosphere within the container.

[0005] As microelectronic devices become smaller and the number of microelectronic features per area of ​​semiconductor devices increases, the devices become more sensitive to particles and environmental contaminants. With smaller microelectronic devices, contaminants with increasingly smaller sizes, even molecular-scale contaminants, can destroy the performance of the microelectronic devices. Therefore, there is a need for continuous improvement in the control of particle contamination during all stages of processing semiconductor substrates, including during transport of substrates between process steps.

[0006] There is an ongoing need for improved systems and methods of controlling the gaseous environment within a substrate container to maintain a high level of cleanliness and avoid contamination of substrates during handling. Summary of the invention

[0007] During use of a substrate container, the gaseous atmosphere inside the container may be replaced by a new gaseous atmosphere for various reasons. To allow this, the container may include a gas port (i.e., an opening or "inlet") through which gas may be delivered to or removed from the interior of the container.

[0008] As an example, a high purity, clean and dry gas (referred to as a "cleaning gas") may be dispensed into the container interior to replace (i.e., displace) the previous atmosphere. When a substrate is inserted into the container interior, the substrate may contain moisture at its surface that may be transferred into the container atmosphere. At a desired time before removing the substrate from the container interior, before or after removing the container door, the container atmosphere may be replaced with a new gaseous atmosphere that does not contain moisture, i.e., the container interior is "cleaned" with a dry atmosphere. Some cleaning methods use nitrogen as the dry cleaning gas to replace the container atmosphere. Other cleaning methods use clean dry air as the cleaning gas.

[0009] The choice of using nitrogen or clean dry air as the cleaning gas may depend on the type of substrate being processed, the type of process being performed on the substrate, and the user's preference. The purpose of the cleaning step may be to remove moisture vapor from the container. Nitrogen or clean dry air effectively removes moisture. But some processes are sensitive to the presence of oxygen. For these processes, nitrogen has the benefit of reducing the oxygen content in the container compared to clean dry air containing oxygen. Nevertheless, for manufacturing processes that are not highly sensitive to the presence of oxygen and the cost of nitrogen is relatively high or extremely high, clean dry air is the preferred cleaning gas. To the best of the applicant's knowledge, commercial processes use one or the other of nitrogen or clean dry air, but do not use a cleaning gas that is a mixture or combination of clean dry air and nitrogen.

[0010] In addition to effectively removing moisture, a preferred commercial cleaning step should be performed with efficient throughput. In this regard, the length of time required to perform the cleaning step can be important. Longer times required for the cleaning step will reduce the throughput and overall efficiency of the manufacturing process, while reduced times required for the cleaning step will advantageously increase throughput and overall efficiency.

[0011] As determined by the applicant, commercial processes that use one or the other of nitrogen (pure nitrogen) or clean dry air alone and do not consider the density of the selected cleaning gas produce uneven cleaning of the substrate container between the upper container position and the lower container position. The uneven cleaning causes an increase in the amount of time to complete the cleaning step.

[0012] In more detail, the container atmosphere contains moisture due to moisture present at the surface of the substrate when the substrate is placed within the container interior, or due to the amount of moisture in the container atmosphere when the atmosphere is enclosed within the container interior, or both. Since dry air as a cleaning gas is denser than humid air of the container atmosphere, dry air as a cleaning gas tends to flow quickly through the lower portion of the substrate container interior, while requiring a significantly longer period of time to eventually replace the less dense humid atmosphere at the upper container location. Conversely, nitrogen as a cleaning gas is lighter than humid air and quickly replaces the atmosphere at the upper container location, but requires a significantly longer amount of time to replace the atmosphere at the lower portion of the container.

[0013] As determined by the applicant, by controlling the density of the cleaning gas by virtue of using a cleaning gas having a density approximately the same as the density of the container atmosphere, the uniformity of the flow of the cleaning gas through the upper and lower portions of the interior of the substrate container can be improved. A cleaning gas having a density close to the density of the humid air within the container interior will displace the humid air at the upper and lower container locations in a significantly more uniform manner. With a more uniform flow of cleaning gas through the container, the amount of time required for the cleaning step is reduced compared to the amount of time that would be required using a cleaning gas having a density significantly different than the density of the container atmosphere.

[0014] As described herein, the density of the cleaning gas can be selected and controlled to match the density of the atmosphere present inside the substrate container in a manner that improves the uniformity of the flow of the cleaning gas through the interior of the container and reduces the amount of time required to complete the cleaning step. The density of the cleaning gas can be controlled by selecting a composition of the cleaning gas that has a density close to the density of the humid air contained in the interior of the container. The cleaning gas can be a mixture of two different types of cleaning gases, such as clean dry air or oxygen mixed with nitrogen (pure nitrogen), and the mixture can have a density approximately equal to the density of the humid air of the container atmosphere. Alternatively or in addition, the cleaning gas can be a single type of cleaning gas (e.g., pure nitrogen or clean dry air), or a combination of different cleaning gas components (e.g., nitrogen and oxygen), which is at a temperature at which the cleaning gas has a density approximately equal to the density of the humid air of the container atmosphere.

[0015] In one aspect, the invention relates to a method of cleaning a substrate container with a cleaning gas. The substrate container comprises: a container body including an opening; a door adapted to cover the opening; an interior defined by the container body; a substrate supported within the interior; a container atmosphere within the interior; and one or more cleaning gas inlets at the interior. The method comprises dispensing a cleaning gas into the interior through the one or more inlets and the cleaning gas comprises: clean dry air received from a clean dry air source, and nitrogen received from a nitrogen source.

[0016] In another aspect, the invention relates to a method of cleaning a substrate container with a cleaning gas. The substrate container comprises: a container body including an opening; a door adapted to cover the opening; an interior defined by the container body; a substrate supported within the interior; a container atmosphere within the interior; a cleaning gas inlet at the interior; and a cleaning gas source. The method comprises: measuring a relative humidity of the container atmosphere, controlling a density of the cleaning gas based on the relative humidity of the container atmosphere, and dispensing the cleaning gas into the interior through the inlet.

[0017] In yet another aspect, the present invention is directed to a substrate container system comprising: a container body having an opening; a door adapted to be placed over and removed from the opening; an interior defined by the container body; a substrate supported within the interior; a container atmosphere within the interior; a clean gas inlet at the interior; and a clean gas source comprising a clean dry air source and a nitrogen source. The system also includes a clean gas flow control system that combines a flow rate of the clean dry air and a flow rate of the nitrogen to produce a clean gas mixture.

[0018] According to yet another aspect, the present invention is directed to a substrate container system comprising: a container body having an opening; a door adapted to be placed over and removed from the opening; an interior defined by the container body; a clean gas inlet connected to the interior; a relative humidity sensor; a clean gas source; and a control system for controlling the density of the clean gas dispensed into the interior through the clean gas inlet.

[0019] According to yet another aspect, the present invention is directed to a method comprising dispensing a cleaning gas mixture through an inlet of a substrate container, wherein the cleaning gas mixture comprises a combination of clean dry air and nitrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a perspective view of an example wafer container as described.

[0021] Figure 2 is a side cross-sectional view of an example wafer container.

[0022] Figure 3A , 3B and 3C are side cross-sectional views of a wafer container and a conventional method of cleaning the wafer container.

[0023] Figure 4A , 4B 4C is a side cross-sectional view of an example wafer container of the present description.

[0024] Figure 5Aand 5B is a side cross-sectional view of an example wafer container and method of cleaning the same as described herein.

[0025] Fig. 6A , 6B 6C is a side cross-sectional view of a wafer container and a conventional method of cleaning the wafer container.

[0026] Fig. 7A and 7B is a side cross-sectional view of an example wafer container and method of cleaning the wafer container as described.

[0027] All figures are schematic and not to scale. DETAILED DESCRIPTION

[0028] A substrate container is described below, comprising a container body having an interior, an opening on one side of the body for accessing the interior, and a door adapted to cover and seal the opening. The container also comprises one or more gas ports, including an inlet that can be used to dispense a gas (e.g., a "cleaning gas") into the interior of the container.

[0029] The container can be used as a component of a system (e.g., a "substrate container system") that includes other devices, structures, or raw material sources used with the substrate container to handle substrates in a clean environment. Example components of the substrate container system include any one or more of the following: a clean gas source; optionally, separate sources of two or more different types of clean gases; a sensor to measure the condition of the container, the system, or the process material (clean gas), such as a temperature sensor, a pressure sensor, or a humidity sensor; a control device, such as a temperature control device to control the temperature of the clean gas delivered to the interior of the container and thereby control its density, or a flow control device to control the flow of a single clean gas, two different clean gases, or a mixture of two or more different clean gases ("clean gas mixture"); a process control system to control the conditions of the cleaning process and the process steps, etc.

[0030] Also described are methods of introducing a cleaning gas into the interior of a container while controlling the composition of the cleaning gas, the temperature of the cleaning gas, the density of the cleaning gas, or a combination of these. According to example methods and systems, the composition, temperature, or density of the cleaning gas may be selected so that the cleaning gas displaces ("cleans") the atmosphere within the container to a high degree of efficiency. In example methods, to achieve efficiency in the cleaning step, the cleaning gas may be controlled to have a density close to the density of the atmosphere in the container that is displaced by the cleaning gas. A cleaning gas having a density similar to or the same as the density of the container atmosphere will displace the container atmosphere in a substantially uniform manner throughout the interior of the container, while a cleaning gas having a density significantly different from the density of the container atmosphere will displace the container atmosphere in a less efficient (e.g., less uniform and less rapid) manner.

[0031] In an example method, the cleaning gas may contain a mixture of two or more different types of cleaning gases provided from two or more separate gas sources. As an example, the system may deliver two different types of cleaning gases to the interior of the container, the two types including clean dry air as one type of cleaning gas and nitrogen as a second type of cleaning gas, wherein the clean dry air is provided from a clean dry air source and the nitrogen is provided from a pure nitrogen source. As another example, instead of clean dry air and nitrogen as the two different types of cleaning gases, the system may include an oxygen source as one type of cleaning gas and a nitrogen source as the second type of cleaning gas. The nitrogen from the nitrogen source and the oxygen from the oxygen source may each optionally be delivered to the container as a mixture.

[0032] As used herein, the term "nitrogen" refers to pure nitrogen, meaning nitrogen containing at least 99.9% or 99.99% (molar) nitrogen and less than 0.01% or less than 0.001% (molar) moisture. The term "clean dry air" refers to a gaseous composition that would be considered sufficiently pure and free of moisture to be used as clean dry air in a commercial step of processing semiconductor or microelectronic substrates; this includes a gas containing approximately 78 mole% nitrogen (N2) and approximately 21 mole% oxygen (O2), and less than 0.01% or less than 0.001% (molar) moisture. An example of a clean dry air product is ultra-high purity Ultra Clean Dry Air available from Entegris Corporation of Billerica MA. The term "oxygen" refers to pure oxygen, meaning oxygen containing at least 99.9% or 99.99% by mole oxygen and less than 0.01% or less than 0.001% by mole water.

[0033] In these or other examples, the system can process and treat (e.g., heat or cool) the cleaning gas to have a desired density when the cleaning gas is delivered to the interior of the container. A useful cleaning gas density can be a density that is approximately the density of the container atmosphere that is displaced by the cleaning gas; for example, the cleaning gas can have a density that is within 10%, or within 5%, or within 2%, or within 1% of the density of the container atmosphere. The cleaning gas can be a single type of cleaning gas, such as pure nitrogen ("nitrogen") or clean dry air, or can be a cleaning gas mixture prepared from two different types of cleaning gases (e.g., by combining a flow of nitrogen from a nitrogen source with a flow of clean dry air from a clean dry air source).

[0034] The wafer container includes a multi-sided container body (sometimes referred to as a "shell") that defines a container interior adapted to accommodate and support one or more semiconductor wafers. The body includes an opening on one side of the container body that allows access to the container interior ("container opening" or "opening"). The container also includes a door that is adapted to cover the opening and form a seal over the opening between the container interior and the outside of the container. The substrate container typically may include at least one inlet port adapted to allow a gas (e.g., a "cleaning gas") to be delivered to the container interior, and at least one (optional) outlet port that allows gas from the container interior to flow out of the interior and pass to the outside. Optionally, a delivery device, sometimes referred to as a "diffuser", may be connected to the inlet port. The diffuser can be used to distribute the clean gas throughout the container interior, for example, by dispensing the clean gas along the length of the diffuser with the diffuser positioned vertically along the height of the container interior.

[0035] The substrate container is adapted to hold a plurality of substrates. A "substrate" may be any of a variety of substantially flat structures known to be of the type that are typically contained or transported in a substrate container device to allow safe and clean handling and transport of substrates without causing damage or contamination of the substrates. Example substrates include semiconductor wafers, precursors thereof, derivatives thereof, and in-process versions of any of these, including in-process semiconductor wafers, in-process microelectronic devices, EUV (extreme ultraviolet) masks, panels, or other structures known to be carried or held in a carrier as described herein, any of which may be collectively referred to as a "wafer" or "substrate."

[0036] Figure 1A substrate container that can be used as a component of a substrate container system as described is shown. The substrate container 1 includes a container body (e.g., a "shell") 2, a front opening 4, an interior 8, a port 10 in the form of an opening through a bottom wall of the shell 2, and slots 12 at opposing side walls. The slots 12 are adapted to engage and support the edges of multiple substrates (not shown) when the substrates are held within the interior 8. The substrate container 1 also includes a door 6 that can be used to cover the opening 4 to close and seal the interior 8.

[0037] The substrate container 1 can be used to transport, hold or store semiconductor wafers (substrates) that are processed through a series of processing steps between the series of steps (i.e., "in-process" wafers). As illustrated, the substrate container 1 is a front-opening container, such as a "front-opening unified wafer transport box" or "FOUP".

[0038] The container body 2 defines an interior 8 within the container 1, wherein an opening 4 is provided on one side of the container body 2 to allow access to the interior 8. The open side 4 allows a plurality of wafers to be placed within the interior 8 of the container body 2 while being supported at the slot 12. A door 6 may be used to cover the opening 4. When the opening 4 is covered by the door 6, a seal is formed by a gasket (not shown) between the door and the container. The sealed interior of the container 1 is a microenvironment that is protected from contaminants outside the container 1.

[0039] The substrate container as described is a component of a system (e.g., a "substrate container system") that includes a substrate container and one or more accessory devices that can engage the substrate container during use (e.g., during steps of opening or closing the substrate container, inserting or removing a substrate into or from the interior of the container, adding a gaseous atmosphere to the interior of the container, etc.). The accessory devices that can be incorporated into the system, which is referred to as a "loadport," can include: one or more clean gas sources; clean gas controls that can include flow control devices to control the volume or amount of clean gas flow, temperature control devices to control the temperature of the clean gas, mixing controls that combine two flows of different clean gases into a single clean gas mixture; measurement systems that measure or monitor conditions of the container (e.g., temperature, pressure, or humidity of the interior of the container or the atmosphere); and control systems that communicate with the substrate container system to affect or control conditions within the container or to control conditions (e.g., temperature) or flow rates of the clean gas.

[0040] An example control system may be adapted to receive input from a substrate container system, such as a temperature, pressure, or relative humidity measurement of the container atmosphere, and using that information may control the composition, temperature, or density of the cleaning gas dispensed into the container interior. An example control system may perform this function using at least a computerized hardware processor having a memory device operably connected to the processor. The memory may store instructions to be executed at the processor. According to various example systems of the present description, the control system may include any form of microprocessor as a computer processor, such as a process logic controller (PLC controller) embedded in an application specific integrated circuit (ASIC) or the like.

[0041] In an example system, one or more sensors may be positioned relative to the substrate container system at a location to measure the temperature, pressure, relative humidity, or two or more of these of the container atmosphere. The sensor may be located at the container interior, at an inlet to measure the condition of the gas flowing into the interior, at an outlet to measure the condition of the gas flowing from the container, at a clean gas source, or at any other effective location. The process control system may receive one or more measured values ​​from the system and use the information to select the composition, temperature, or density of the clean gas to be delivered to the container interior. The density of the clean gas may be controlled based on the composition (chemical composition) of the clean gas, based on the temperature of the clean gas, or a combination of these.

[0042] To deliver a clean gas having a desired composition, density, or temperature, the processor is adapted to execute instructions stored by the memory to perform one or more flow or temperature control functions. By one example of a useful method, the process control system measures the temperature, pressure, relative humidity, or a combination thereof of the container atmosphere. The control system contains software or hardware that is programmed to determine (or approximate) the density of the container atmosphere (i.e., "container atmosphere density" or "container atmosphere density value") using the measured conditions of the container atmosphere.

[0043] By one approach, the control system may be programmed to use one or more measured container conditions (e.g., temperature, pressure, relative humidity of the container atmosphere) as input to a calculation that will determine or approximate the density of the container atmosphere. As a specific example, the system may be programmed to identify a container atmosphere density value using the ideal gas law in conjunction with one or more other chemical relationships of humid air to the measured temperature, pressure, and relative humidity values.

[0044] As a different way that the container atmosphere density value can be determined, the memory may contain one or more correlation graphs or tables that relate the density of moist air to values ​​of conditions of the moist air (e.g., temperature, pressure, and relative humidity). These correlations may be determined empirically, may be based on multiple calculations performed (optionally iteratively), or may be determined in any other effective manner. By any useful method, the system uses measured conditions of temperature, pressure, or relative humidity, or a combination of these, and relates one or more of the measured conditions to the density of the moist air of the container atmosphere (i.e., approximately calculates the container atmosphere density).

[0045] Once the control system has identified the container atmosphere density value, the control system can dispense the cleaning gas into the container interior while controlling the density of the cleaning gas ("clean gas density") to be approximately the same as the container atmosphere density value, e.g., within 10% or 5% of the container atmosphere density value. The cleaning gas density can be controlled by controlling the composition of the cleaning gas, by controlling the temperature of the cleaning gas, or by controlling both the composition and temperature of the cleaning gas.

[0046] The cleaning gas may be supplied and delivered to the interior of the container according to a novel method that differs from previous methods and systems that use a single cleaning gas, do not control the temperature of the cleaning gas, and do not evaluate or control the density of the cleaning gas.

[0047] By one example method, the cleaning gas is supplied from two different cleaning gas sources, each source supplying a different type (chemical composition) of cleaning gas. By such an approach, the two different types of cleaning gases can be delivered to the interior of the container separately, or the two different cleaning gases can be combined and delivered to the interior of the container as a cleaning gas mixture.

[0048] By various example methods, a single type of cleaning gas or a cleaning gas mixture may be delivered to the interior of a container while controlling the temperature of the cleaning gas or the cleaning gas mixture to thereby control the density of the cleaning gas delivered to the interior of the container. The temperature of the cleaning gas or the cleaning gas mixture may be controlled by any method or device, such as by a cooling device or a heating device (e.g., a heat exchanger) that removes or adds thermal energy to the cleaning gas or the cleaning gas mixture, or by passing the cleaning gas or the cleaning gas mixture under pressure through an orifice to cause the cleaning gas or the cleaning gas mixture to expand and reach a reduced temperature.

[0049] As a comparison with previous cleaning systems and methods, Figure 2An example of a substrate container as part of a substrate container system is shown that does not include but can be adapted to include features of substrate containers and systems as described herein. System 100 includes a substrate container 102 having an (inner) FOUP door 118, an outer (Front Opening Interface Mechanical Standard FIMS) door 122, which may be part of a separate device (such as a load port) and contains a plurality of substrates 104 held within an interior 106. The container 102 includes an inlet 110 to allow gas to flow into the interior 106, and an outlet 116 to allow gas to flow from the interior 106 to the exterior of the container 102 as an exhaust 130. The system 100 also includes a clean gas source 120, which may be a source of any useful clean gas, such as nitrogen or clean dry air (e.g., "XCDA"). A flow meter 124 controls the flow of the clean gas from the source 120 to the inlet 110 and into the interior 106. The container 102 also includes an opening (not shown) through a side of the container that allows access to the interior 106, and a door (not shown) that can be selectively placed over or removed from the opening. The system 100 as described does not include a second type of cleaning gas, and does not include a device or control system adapted to control the temperature or density of the cleaning gas delivered to the interior 106.

[0050] In use, the container 102 is used to hold a substrate 104 (for example, for transporting the substrate). The substrate 104 may be initially placed within the interior 106 with the door 118 of the container removed. After the substrate 104 is placed at the interior, the door 118 is placed over the opening to enclose and seal the container interior with the substrate inside. During the time that the substrate is placed at the interior, the atmosphere within the interior 106 will be that of the environment of the substrate and the container, which is typically a clean room atmosphere. A typical clean room atmosphere for processing semiconductor and microelectronic products will have a relative humidity of less than 60% (e.g., less than 50%, for example, in the range of from 20% to 60%, such as from 40% to 50%) at ambient temperature (e.g., approximately 22 degrees Celsius (e.g., from 20 degrees Celsius to 25 degrees Celsius)) and ambient pressure (approximately 1 atmosphere). When the door is placed over the opening, the container interior contains this clean room atmosphere (including the moisture content of the clean room environment).

[0051] When the substrate is placed inside the container, the substrate may have moisture (e.g., absorbed moisture) at the surface of the substrate. The atmosphere of the clean room at the interior of the container may also contain moisture. When the substrate is placed into the container, the amount of moisture in the container atmosphere may change due to the wetness or dryness of the substrate surface. During the period when the substrate is contained inside the enclosed container, the moisture from the substrate surface will be balanced with the moisture (humidity) in the container atmosphere. When the container is opened to remove the substrate, the container atmosphere may have a relative humidity in a large potential range, such as greater than 2% (at 21 degrees Celsius) and up to 100% relative humidity, for example, at ambient temperature (e.g., 22 degrees Celsius) can be anywhere from 5%, 10%, 20% or 30% to 50%, 60%, 70%, 80%, 90% or 100% relative humidity.

[0052] For various reasons and at different stages of handling substrates with a substrate container, the container atmosphere may be replaced with a different atmosphere, typically an atmosphere of gas that does not contain a large amount of moisture. For example, the container atmosphere may be purged with a dry gas during or before the door of the substrate container is opened. As a different example, the container atmosphere may be purged at a time between process steps, or after the container has been closed and the container has left the load port. Alternatively, the container atmosphere may be purged at a time after storage and movement of wafers held in the container, at the time of unloading the container when the door is removed from the container.

[0053] As part of a process of opening a substrate container to remove substrates of the type used in semiconductor and microelectronic processing, the gaseous atmosphere at the interior of the container may be cleaned to replace (displace) the container atmosphere of humid air with a new dry gaseous atmosphere. The step of cleaning the interior of the container may be used to displace the atmosphere within the container, which atmosphere contains a certain amount of moisture in the form of humidity. The cleaning step may be performed with the door open (removed) or with the door closed (attached and covering the interior). The container atmosphere containing humidity is replaced with a different atmosphere of dry gas, such as clean dry air or nitrogen (meaning pure nitrogen) to eliminate moisture, which, if allowed to remain with the substrate, may act as a contaminant or impurity at the surface of the substrate, may cause oxidation or another chemical reaction and may reduce yield.

[0054] According to conventional methods of cleaning humid air from a substrate container containing microelectronic or semiconductor substrates, nitrogen or clean dry air is used as a cleaning gas to clean the interior. Users of substrate containers in the microelectronic and semiconductor processing industries choose nitrogen or clean dry air as a cleaning gas. To the best of the applicant's knowledge, commercial systems and methods are not designed to use a combination of clean dry air and nitrogen together as a cleaning gas.

[0055] Applicants have identified that the limited choice of using nitrogen or clean dry air as a cleaning gas results in relatively inefficient cleaning of a container atmosphere of humid air. The difference in density of either of these types of cleaning gases compared to the density of a container atmosphere of humid air can lead to inefficiencies.

[0056] The density difference between the cleaning gas and the container atmosphere can cause the flow of the cleaning gas through the container interior to be significantly non-uniform at different vertical locations within the container interior. A cleaning gas having a higher density than the density of the container atmosphere will tend to flow below the container atmosphere at least initially along the bottom portion of the container interior, and may tend to first displace the container atmosphere located at the bottom portion and more slowly displace the container atmosphere located at the top portion ("upper portion") of the container. Conversely, a cleaning gas having a lower density than the density of the container atmosphere will tend to flow above the container atmosphere at least initially along the top portion of the container interior, and may tend to first displace the container atmosphere located at the top portion of the container interior and more slowly displace the container atmosphere located at the lower portion or bottom portion of the container.

[0057] For a typical process of cleaning humid air from the interior of a substrate container that holds substrates used in semiconductor or microelectronic processing, the container atmosphere will be at ambient temperature and will have a relative humidity in the range of from 2% to 100%. For many such processes, the density of the humid air will be in the range of from 1.1 to 1.25 kg / m3 (e.g., from 1.15 to 1.21 kg / m3). According to the method as described, the cleaning gas can have a density that approaches or matches the density of humid air and can be within these density ranges. The cleaning gas can have any composition and can be prepared, processed, and disposed in any useful manner to have a density that approaches or matches the density of the humid air of the container atmosphere.

[0058] By example technology, the density of the clean gas can be controlled by controlling the chemical composition (composition) of the clean gas. In an example, the clean gas may contain a combination of two different types of clean gases (i.e., a clean gas mixture), wherein the chemical composition of the clean gas mixture is selected to have a density close to the density of moist / humid air in the container atmosphere. Clean dry air has a density greater than moist air, while nitrogen has a density less than moist air. By increasing the concentration of nitrogen in the clean dry air, the density of the clean dry air can be reduced to a density close to that of moist air, and more generally, a clean gas mixture with the density of moist air can be produced by combining a large amount of clean dry air with a small amount of nitrogen. The specific density of the clean gas mixture can be controlled by controlling the relative amounts of nitrogen and clean dry air in the clean gas. According to the example method as described, the amount of nitrogen added to the clean dry air can be sufficient to produce a clean gas mixture having approximately the same density as the moist air of the container atmosphere being cleaned.

[0059] For a typical process for cleaning wet air from the interior of a substrate container holding semiconductor or microelectronic substrates, a cleaning gas mixture made of (consisting of or consisting essentially of) a combination of clean dry air and nitrogen may contain from 50 mol % to 97 mol % clean dry air and from 3 % to 50 mol % nitrogen (with less than 0.01 mol % or 0.001 mol % water).

[0060] Depending on the relative amounts of nitrogen and oxygen in the cleaning gas, an example cleaning gas mixture may contain from 78.5 mol% or 79 mol%, up to 98.5 mol% nitrogen and from 20.5 mol% or 20 mol% to 0.5 mol% oxygen (with less than 0.01 mol% or 0.001 mol% water). Such a cleaning gas mixture may be prepared by combining clean dry air with nitrogen, by combining nitrogen with oxygen, or by combining any two or more different types of cleaning gases.

[0061] As an additional or alternative way to control the density of the cleaning gas, the density may be controlled by controlling the temperature of the cleaning gas. For example, nitrogen at ambient temperature has a density less than the density of humid air at ambient temperature. To control the density of the nitrogen to be approximately the same as the density of humid air (e.g., to have a density in the range of from 1.1 to 1.25 kg / m3), the temperature of the nitrogen may be controlled to be a temperature less than the temperature of the humid air of the container atmosphere (at a common ambient pressure). For a typical process of cleaning humid air from the interior of a substrate container holding a semiconductor or microelectronic substrate, the nitrogen provided to the container atmosphere may have a temperature in the range of from 11 degrees Celsius to 15 degrees Celsius.

[0062] Clean dry air at ambient temperature has a greater density than the density of humid air at ambient temperature. To make the clean dry air have approximately the same density as the humid air (e.g., having a density in the range of from 1.1 to 1.25 kg / m3), the temperature of the clean dry air can be controlled to be higher than the temperature of the humid air of the container atmosphere. For a typical process of cleaning humid air from the interior of a substrate container holding semiconductor or microelectronic substrates, the clean dry air can be provided to the container atmosphere at a temperature in the range of from 20 to 23 degrees Celsius.

[0063] refer to Figure 3A , the system 100 is shown as having a container atmosphere 140 of humid air (shaded) filling an interior space including an upper or top portion 106a and a lower or bottom portion 106b. Figure 3A , 3B In the example of 3C, both the (inner) FOUP door 118 and the outer (Front Opening Interface Mechanical Standard FIMS) door 122 are closed. Figure 3B The steps of delivering clean dry air from a clean dry air source into the interior 106 through the inlet 110 are shown. The clean dry air flows through the interior 106 and exits the interior 106 as exhaust 130. The clean dry air (darker shaded) 142, which is free of moisture, has a greater density than the density of the humid air 140 of the container atmosphere. With a higher density, the clean dry air 142 tends to flow through the bottom portion 106b of the interior 106. This results in a reduced flow of the clean dry air 142 through the upper portion 106a and a slower replacement of the humid air 140 by the clean dry air 142 at the upper portion 106a.

[0064] Figure 3C Various examples of inefficient cleaning steps using nitrogen 144 are shown. Figure 3A , the conventional system 100 is shown with a container atmosphere (shaded) of humid air 140 filling an interior space 106 including an upper or top portion 106a and a lower or bottom portion 106b. Figure 3C The step of delivering nitrogen gas 144 from nitrogen source 120 into interior 106 through inlet 110 is shown. Nitrogen gas 144 has a density less than the density of the humid air of container atmosphere 140. Nitrogen gas 144 tends to flow more through upper portion 106a of interior 106. This results in a reduced flow of nitrogen gas 144 through bottom portion 106b and a slower replacement of humid air container atmosphere 140 by nitrogen gas 144 at bottom portion 106b.

[0065] The methods and systems of the present description can perform steps of cleaning the humid air atmosphere of a substrate container in a manner that improves flow uniformity between the top and bottom portions of the interior of the container. Cleaning steps involving improved uniformity of flow of cleaning gas through different portions (top and bottom portions) of the substrate container can be more efficient, e.g., can be completed in a shorter amount of time, compared to cleaning steps having non-uniform cleaning gas flow at different top and bottom portions of the interior of the container. In example methods and systems, the density of the cleaning gas used to replace the humid air container atmosphere is controlled to be close to the density of the container atmosphere being replaced.

[0066] In an example system, a substrate container system may include a sensor and a process control system adapted to determine (e.g., estimate or approximate) a value of the density of a container atmosphere displaced from the container interior. Using the process control system, the substrate container system may determine the density value of the container atmosphere and, in response to the density value, may control the density of a cleaning gas that enters the container interior to displace the container atmosphere.

[0067] Conditions of the system, including the temperature, pressure, and relative humidity of the container atmosphere, can be measured by sensors adapted to measure these conditions. Any of a number of these sensors can be included as part of the system at a location that will effectively measure the conditions. For example, the sensor can be located inside the container, or at or near the outlet of the container.

[0068] Using one or more of the measured conditions, a density value for the humid air container atmosphere may be determined or approximated by comparing those conditions to information stored in a memory of the process control system that relates previously evaluated and tabulated conditions of pressure, temperature, and relative humidity of the humid air to a density value for the humid air. Alternatively, the measured conditions may be used to calculate a value for the density of the humid air of the container atmosphere using a known mathematical equation that may identify a density value for the humid air based on measured relative humidity, pressure, temperature, or a combination of these.

[0069] The example system described in this paper is Figure 4A 206. The system 200 is illustrated and includes a substrate container 202 that contains a plurality of substrates 204 held within an interior 206. The container 202 includes an inlet 210 to allow a clean gas to flow into the interior 206, and an outlet 216 to allow a gas to flow from the interior 206 to the exterior of the container 202 as an exhaust 230. The container 202 also includes an opening (not shown) through a side of the container that allows access to the interior 206, and an inner door 218 that can be selectively placed over or removed from the opening. An outer door 222, such as a load port, can also be selectively opened and closed to allow access to the inner door 218 and the container 200.

[0070] The system 200 also includes two separate cleaning gas sources 220a and 220b, which may be sources of any two different cleaning gases, such as a nitrogen source and a clean dry air source. Flow meters 224a and 224b independently control the flow of the two different cleaning gases from the sources 220a and 220b to the inlet 210 and into the interior 206. As shown, the two different cleaning gases flowing from the two different cleaning gas sources 220a and 220b are combined to form a single combined cleaning gas (or "cleaning gas mixture") that flows into the inlet 210.

[0071] The substrate container system 200 also includes a control system including a microprocessor 250 connected to the sensors and flow control devices of the system 200. The microprocessor 250 is connected to both the flow control devices 224a and 224b and to one or more sensors 226 adapted to measure one or more of the pressure, temperature, and relative humidity of the humid air of the container atmosphere at the interior 206. The process control system can measure the conditions of the container atmosphere, determine a density value of the container atmosphere, and based on the density value, can deliver a clean gas mixture having a density close to the density value of the humid air container atmosphere to the interior 206. The system can control the density of the clean gas by combining nitrogen and clean dry air in relative amounts that will produce a clean gas mixture having a density close to the density value of the container atmosphere.

[0072] As different examples, Figure 4B The system 200 also includes two separate clean gas sources 220a and 220b, and additionally includes a temperature control device 232 that can be used to control the temperature of the clean gas mixture produced by combining a certain amount of nitrogen from source 220b with the clean dry air from source 220a. The temperature of the clean gas mixture can be controlled to further control the density of the clean gas mixture delivered to the interior 206.

[0073] refer to Figure 4C , the system 200 includes only a single clean gas source 220, which can be a nitrogen source or a clean dry air source, or a different gas. A flow meter 224 controls the flow of the clean gas from the source 220 to the inlet 210 and into the interior 206. The system 200 also includes a temperature control device 232, which can be used to control the temperature and therefore the density of the clean gas delivered from the source 220 to the interior 206.

[0074] The substrate container system 200 as illustrated includes a control system that includes a microprocessor 250 connected to sensors and flow control devices of the system 200. Figure 4A, the microprocessor 250 is connected to both flow control devices 224a and 224b and to one or more sensors 226, which are adapted to measure one or more of the pressure, temperature and relative humidity of the humid air of the container atmosphere to be contained at the interior 206. Figure 4B and 4C The process control system of the example substrate container system 200 is comparable, with the following exceptions: Figure 4B The control system is further in communication with the temperature control device 232; Figure 4C The control system communicates with the temperature control device 232, but only with the single flow meter 224.

[0075] Each example process control system can measure the condition of the container atmosphere, determine (by any useful method or approximation) the density value of the container atmosphere, and based on the density value, can deliver a clean gas or clean gas mixture having a density close to the density value of the container atmosphere to the interior 206; the example system can control the composition of the clean gas mixture ( Figure 4A ), by controlling the temperature of a single type of clean gas ( Figure 4C ), or by controlling both the temperature and composition of the cleaning gas mixture ( Figure 4B ) to control the density of the clean gas.

[0076] In use, the container 202 of each example holds a substrate 204, for example, for transporting the substrate. When the substrate 204 is placed at the interior 206, the atmosphere within the interior 206 will be the atmosphere of the environment of the substrate and the container, which is typically a clean room atmosphere. The substrate 204 may have moisture at the substrate surface (e.g., absorbed moisture) and that moisture will become moisture within the container atmosphere. At the time the container is open, the container atmosphere will have any relative humidity greater than 2% (at an ambient temperature of, for example, 22 degrees Celsius), for example, a relative humidity of anywhere from 5% to 100%, typically from 40% to 50% (at an ambient temperature of, for example, 22 degrees Celsius). To remove the humid air of the container atmosphere, the container interior is cleaned with a dry cleaning gas.

[0077] refer to Figure 5A , Figure 4B The system 200 is shown having a container atmosphere 240 (shaded) filling an interior space 206 including an upper and top portion 206a and a lower or bottom portion 206b. Figure 5B The step of delivering a clean gas mixture 246 (lighter shaded) prepared by combining two different clean gas sources (eg, clean dry air source 220b and nitrogen source 220a) into interior 206 through inlet 210 is shown.

[0078] exist Figure 5BThe clean gas density may be controlled by controlling the composition of the clean gas mixture 246 (i.e., the relative amounts of nitrogen and clean dry air), or by controlling the temperature of the clean gas mixture 246, or by controlling both the composition and temperature of the clean gas mixture 246. Alternatively, the example system may control the clean gas density by controlling only the clean gas temperature (see Figure 4C ), or by controlling only the cleaning gas composition (see Figure 4A ) to control the cleaning gas density of a single type of cleaning gas (not a mixture).

[0079] In each instance ( Figure 4A , 4B 4C), the container atmosphere 240 has a density that can be determined or estimated by any useful measurement technique, calculation, or comparison of the conditions of the atmosphere 240 with empirical data that relates the pressure, temperature, or relative humidity of humid air to the density of humid air. The clean gas (e.g., clean gas mixture) 246 can be controlled to have a composition, temperature, or both that will result in a clean gas density that is approximately equal to the density of the container atmosphere 240. This results in a relatively uniform flow of the clean gas 246 through the upper portion 206a and the lower portion 206b, such as Figure 5B Place display.

[0080] Example systems and methods may also be used when doors 118 and 122 are in an open position (where the front opening of the container is uncovered to allow wafers to be removed from interior 106, such as Fig. 6A , 6B and 6C) to perform container cleaning steps.

[0081] refer to Fig. 6A , the conventional system 100 is shown with a container atmosphere 140 (shaded) of humid air filling an interior space including an upper or top portion 106a and a lower or bottom portion 106b. Fig. 6A At 104, the FOUP door 118 and outer door 122 are lowered relative to the front of the container to uncover the front opening of the container and allow access to the interior 106 and the wafers held therein.

[0082] Figure 6BThe steps of delivering clean dry air from a clean dry air source into the interior 106 through the inlet 110 are shown. The clean dry air flows through the interior 106 and exits the interior 106 through the uncovered front opening (see arrows). The clean dry air (darker shading) 142, which does not contain moisture, has a greater density than the density of the humid air of the container atmosphere 140. With a higher density, the clean dry air tends to flow through the bottom portion 106b of the interior 106. This results in a reduced flow of the clean dry air 142 through the upper portion 106a, and a slower replacement of the container atmosphere 140 by the clean dry air 142 at the upper portion 106a. According to this description,

[0083] Figure 6C Various examples of inefficient cleaning steps using nitrogen 144 are shown. Fig. 6A , the conventional system 100 is shown with a container atmosphere 140 (shaded) of humid air filling an interior space including an upper or top portion 106a and a lower or bottom portion 106b. Figure 6C The step of delivering nitrogen 144 from nitrogen source 120 into interior 106 through inlet 110 is shown. Nitrogen 144 flows through interior 106 and exits interior 106 through uncovered front opening (see arrows). Nitrogen 144 has a density less than the density of humid air 140 of the container atmosphere. Nitrogen 144 tends to flow more through upper portion 106a of interior 106. This results in a reduced flow of nitrogen 144 through bottom portion 106b and a slower replacement of container atmosphere 140 by nitrogen 144 at bottom portion 106b.

[0084] refer to Fig. 7A , the system 200 is shown with a container atmosphere 240 (shaded) of humid air filling an interior space 206 including an upper or top portion 206a and a lower or bottom portion 206b. Figure 7B The step of delivering a clean gas mixture 246 (lighter shaded) prepared by combining two different clean gas sources (eg, clean dry air source 220b and nitrogen source 220a) into interior 206 through inlet 210 is shown.

[0085] exist Figure 7B The clean gas density may be controlled by controlling the composition of the clean gas mixture 246 (i.e., the relative amounts of nitrogen and clean dry air), or by controlling the temperature of the clean gas mixture 246, or by controlling both the composition and temperature of the clean gas mixture 246. Alternatively, the example system may control the clean gas density by controlling only the clean gas temperature (see Figure 4C ), or by controlling only the cleaning gas composition (see Figure 4A ) to control the cleaning gas density of a single type of cleaning gas (not a mixture).

[0086] aspect:

[0087] Aspect 1. A method for cleaning a substrate container with a cleaning gas, the substrate container comprising:

[0088] a container body including an opening,

[0089] a door adapted to cover said opening,

[0090] an interior, which is defined by the container body,

[0091] a substrate supported within the interior,

[0092] a container atmosphere within said interior, and

[0093] one or more clean gas inlets at said interior;

[0094] The method comprises

[0095] Dispensing a cleaning gas into the interior through the one or more inlets, the cleaning gas comprising:

[0096] clean dry air received from a clean dry air source, and

[0097] Nitrogen gas is received from a nitrogen source.

[0098] Aspect 2. The method according to aspect 1, wherein the clean dry air comprises approximately 78 mol % nitrogen (N2) and approximately 21 mol % oxygen (O2).

[0099] Aspect 3. The method according to aspect 1 or 2, wherein the nitrogen has a purity of at least 99.99 mol % nitrogen.

[0100] Aspect 4. The method according to any one of aspects 1 to 3, comprising:

[0101] combining the clean dry air with the nitrogen to produce a clean gas mixture having a gas mixture density, dispensing the clean gas mixture through an inlet, and

[0102] The cleaning gas mixture density is controlled to approximate the density of the container atmosphere.

[0103] Aspect 5. The method according to aspect 4, wherein the cleaning gas mixture comprises:

[0104] From 50 mol% to 97 mol% clean dry air, and

[0105] From 3 mol % to 50 mol % nitrogen.

[0106] Aspect 6. The method according to aspect 4, wherein the cleaning gas mixture comprises:

[0107] from approximately 78.5 mole % to 98.5 mole % nitrogen, and

[0108] From approximately 20.5 mol % to 0.5 mol % oxygen.

[0109] Aspect 7. The method according to any one of aspects 4 to 6, wherein the cleaning gas mixture density is within 5% of the container atmosphere density.

[0110] Aspect 8. A method according to any one of aspects 4 to 7, wherein the clean gas mixture flows between the upper portion of the interior and the lower portion of the interior with better uniformity than a comparable flow of clean dry air alone and compared to a comparable flow of nitrogen.

[0111] Aspect 9. The method according to any one of aspects 4 to 8, comprising measuring the humidity, pressure and temperature of the container atmosphere, and forming the clean gas mixture from several amounts of clean dry air and nitrogen based on the humidity, pressure or temperature of the container atmosphere.

[0112] Aspect 10. The method according to any one of aspects 1 to 10, wherein the cleaning gas mixture has a density in the range from 1.15 to 1.21 kg / m3.

[0113] Aspect 11. The method according to any one of aspects 1 to 10, wherein the door is removed and the opening is uncovered.

[0114] Aspect 12. The method according to any one of aspects 1 to 10, wherein the door covers the opening.

[0115] Aspect 13. A method for cleaning a substrate container with a cleaning gas, the substrate container comprising:

[0116] a container body including an opening,

[0117] a door adapted to cover said opening,

[0118] an interior, which is defined by the container body,

[0119] a substrate supported within the interior,

[0120] a container atmosphere within said interior,

[0121] a clean gas inlet at said interior, and

[0122] Clean gas source;

[0123] The method comprises:

[0124] measuring the relative humidity of the atmosphere of the container,

[0125] controlling the density of the cleaning gas based on the relative humidity of the container atmosphere, and

[0126] The cleaning gas is dispensed into the interior through the inlet.

[0127] Aspect 14. The method according to aspect 13, wherein

[0128] The cleaning gas source comprises:

[0129] A clean, dry air source, and

[0130] Nitrogen source,

[0131] The cleaning gas comprises a cleaning gas mixture, wherein the cleaning gas mixture contains:

[0132] the flow rate of clean dry air received from the clean dry air source, and

[0133] the flow rate of nitrogen received from the nitrogen source, and

[0134] The method includes selecting a rate of the flow of clean dry air and a rate of the flow of nitrogen to control a density of the clean gas mixture.

[0135] Aspect 15. The method according to aspect 13 or 14, comprising controlling the temperature of the cleaning gas mixture to control the density of the cleaning gas.

[0136] Aspect 16. The method according to aspect 13, wherein the cleaning gas consists of clean dry air and the method includes controlling the temperature of the clean dry air to control the density of the clean dry air.

[0137] Aspect 17. The method according to aspect 13, wherein the cleaning gas consists of nitrogen and the method includes controlling the temperature of the nitrogen to control the density of the nitrogen.

[0138] Aspect 18. The method of aspect 17, comprising controlling the temperature of the cleaning gas by flowing the cleaning gas through an orifice to increase the volume of the cleaning gas and change the temperature of the cleaning gas.

[0139] Aspect 19. The method according to any one of aspects 13 to 18, comprising controlling the density of the cleaning gas to be within 10% of the density of the container atmosphere.

[0140] Aspect 20. The method of any one of aspects 13 to 19, wherein when the cleaning gas is dispensed into the interior, the cleaning gas has a density in a range from 1.15 to 1.21 kg / m3.

[0141] Aspect 21. The method according to any one of claims 13 to 20, comprising:

[0142] measuring the humidity, pressure and temperature of the container atmosphere, and

[0143] The density of the cleaning gas is controlled based on the relative humidity, the pressure, and the temperature of the container atmosphere.

[0144] Aspect 22. The method according to any one of aspects 13 to 21, wherein the door is removed and the opening is uncovered.

[0145] Aspect 23. The method according to any one of aspects 13 to 21, wherein the door is removed and the opening is uncovered.

[0146] Aspect 24. A substrate container system comprising:

[0147] a container body including an opening,

[0148] a door adapted to be placed over and removed from the opening,

[0149] an interior, which is defined by the container body,

[0150] a substrate supported within the interior,

[0151] a container atmosphere within said interior,

[0152] a clean gas inlet at said interior,

[0153] A clean gas source comprising:

[0154] A clean, dry air source, and

[0155] A nitrogen source, and

[0156] A clean gas flow control system combines the flow of the clean dry air and the flow of the nitrogen gas to produce a clean gas mixture.

[0157] Aspect 25. The substrate container system according to aspect 24, wherein the control system comprises:

[0158] a first flow meter for controlling the flow of the clean dry air to the clean gas inlet,

[0159] A second flow meter is used to control the flow of the nitrogen gas to the cleaning gas inlet.

[0160] Aspect 26. The substrate container system according to aspect 24 or 25, comprising a temperature control device for controlling the temperature of the cleaning gas.

[0161] Aspect 27. The substrate container system of aspect 25, wherein the temperature control device is a mechanical orifice.

[0162] Aspect 28. A substrate container system according to any one of Aspects 24 to 27, comprising a relative humidity sensor, wherein the clean gas flow control system selects the flow rate of the clean dry air or the flow rate of the nitrogen, or the flow rates of the clean dry air and the nitrogen based on the measured relative humidity of the system.

[0163] Aspect 29. A substrate container system comprising:

[0164] a container body including an opening,

[0165] a door adapted to be placed over and removed from the opening,

[0166] an interior, which is defined by the container body,

[0167] a clean gas inlet connected to the interior,

[0168] Relative humidity sensor,

[0169] Clean gas source, and

[0170] A control system is provided for controlling the density of the cleaning gas dispensed into the interior through the cleaning gas inlet.

[0171] Aspect 30. The substrate container of aspect 29, wherein the control system comprises a mechanical orifice in the flow of the cleaning gas to reduce the temperature of the cleaning gas as the cleaning gas flows through the mechanical orifice.

[0172] Aspect 31. A substrate container according to aspect 27 or 28, wherein

[0173] The cleaning gas source comprises:

[0174] A clean, dry air source, and

[0175] A nitrogen source, and

[0176] The control system comprises:

[0177] a flow meter for controlling the flow of the clean dry air to the clean gas inlet,

[0178] A flow meter is used to control the flow of the nitrogen gas to the clean gas inlet.

[0179] Aspect 32. According to aspect 30 or 31, the cleaning gas source is composed of a clean dry air source, and the control system includes a temperature control device for controlling the temperature of the clean dry air.

[0180] Aspect 33. In the substrate container according to aspect 30 or 31, the cleaning gas source is composed of a nitrogen gas source, and the control system includes a temperature control device for controlling the temperature of the nitrogen gas.

[0181] Aspect 34. A method comprising dispensing a cleaning gas mixture through an inlet of a substrate container, wherein the cleaning gas mixture comprises a combination of clean dry air and nitrogen.

[0182] Aspect 35. The method according to aspect 34, wherein the cleaning gas mixture comprises:

[0183] From 50 mol% to 97 mol% clean dry air, and

[0184] From 3 mol % to 50 mol % nitrogen.

[0185] Aspect 36. The method according to aspect 34, wherein the cleaning gas mixture has a density in the range from 1.1 to 1.25 kg / m3.

[0186] Aspect 37. The method according to any one of aspects 34 to 36, wherein the door is removed and the opening is uncovered.

[0187] Aspect 38. The method according to any one of aspects 34 to 36, wherein the door is removed and the opening is uncovered.

Claims

1. A substrate container system, comprising: a container body including an opening, a door adapted to be placed over and removed from the opening, an interior, which is defined by the container body, a substrate supported within the interior, a container atmosphere within said interior, a clean gas inlet at said interior, A clean gas source comprising: A clean, dry air source, and A nitrogen source, and A clean gas flow control system combines the flow of the clean dry air and the flow of the nitrogen gas to produce a clean gas mixture.

2. The substrate container system of claim 1 , wherein the control system comprises: a first flow meter for controlling the flow of the clean dry air to the clean gas inlet, A second flow meter is used to control the flow of the nitrogen gas to the cleaning gas inlet.

3. The substrate container system of claim 2, comprising a temperature control device for controlling the temperature of the cleaning gas.

4. The substrate container system of claim 2, wherein the temperature control device is a mechanical orifice.

5. The substrate container system of any one of claims 4, comprising a relative humidity sensor, wherein the clean gas flow control system selects the flow rate of the clean dry air or the flow rate of the nitrogen, or the flow rates of the clean dry air and the nitrogen based on the measured relative humidity of the system.

6. The substrate container system of claim 10, further comprising a pressure sensor and a temperature sensor.

7. The substrate container system of claim 11, wherein the humidity sensor measures humidity, the pressure sensor measures pressure, and the temperature sensor measures temperature of the container atmosphere and the control system forms a clean gas mixture from quantities of the clean dry air and the nitrogen based on the humidity, pressure, or temperature of the container atmosphere.

8. A substrate container system comprising: a container body including an opening, a door adapted to be placed over and removed from the opening, an interior, which is defined by the container body, a clean gas inlet connected to the interior, Relative humidity sensor, Clean gas source, and A control system is provided for controlling the density of the cleaning gas dispensed into the interior through the cleaning gas inlet.

9. The substrate container system of claim 8, wherein the control system includes a mechanical orifice in the flow of the cleaning gas to reduce the temperature of the cleaning gas as the cleaning gas flows through the mechanical orifice.

10. The substrate container system of claim 9, wherein The cleaning gas source comprises: A clean, dry air source, and A nitrogen source, and The control system comprises: a flow meter for controlling the flow of the clean dry air to the clean gas inlet, A flow meter is used to control the flow of the nitrogen gas to the clean gas inlet.

11. The substrate container system according to claim 10, wherein the cleaning gas source is composed of a clean dry air source, and the control system comprises a temperature control device for controlling the temperature of the clean dry air.

12. The substrate container system according to claim 10, wherein the cleaning gas source is composed of a nitrogen gas source, and the control system comprises a temperature control device for controlling the temperature of the nitrogen gas.

13. A method for cleaning a substrate container with a cleaning gas, the substrate container comprising: a container body including an opening, a door adapted to cover the opening, an interior, which is defined by the container body, a substrate supported within the interior, a container atmosphere within said interior, and one or more clean gas inlets at said interior; The method comprises Dispensing a cleaning gas into the interior through the one or more inlets, the cleaning gas comprising: clean dry air received from a clean dry air source, and Nitrogen gas is received from a nitrogen source.

14. The method according to any one of claims 13, comprising: combining the clean dry air with the nitrogen to produce a clean gas mixture having a gas mixture density, dispensing the clean gas mixture through an inlet, and The cleaning gas mixture density is controlled to approximate the density of the container atmosphere.

15. The method of any one of claims 14, comprising measuring the humidity, pressure and temperature of the container atmosphere and forming the clean gas mixture from quantities of clean dry air and nitrogen based on the humidity, pressure or temperature of the container atmosphere.

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