Abstract:
The present disclosure relates to methods and apparatus for an atomic layer deposition (ALD) processing chamber for device fabrication and methods for replacing a gas distribution plate and mask of the same. The ALD processing chamber has a slit valve configured to allow removal and replacement of a gas distribution plate and mask. The ALD processing chamber may also have actuators operable to move the gas distribution plate to and from a process position and a substrate support assembly operable to move the mask to and from a process position.

Description:
BACKGROUND 
       [0001]    Field 
         [0002]    Embodiments of the present disclosure generally relate to an apparatus for processing large area substrates. More particularly, embodiments of the present disclosure relate to an atomic layer deposition (ALD) system for device fabrication and in situ cleaning methods for a showerhead of the same. 
         [0003]    Description of the Related Art 
         [0004]    Organic light emitting diodes (OLED) are used in the manufacture of television screens, computer monitors, mobile phones, other hand-held devices, etc. for displaying information. A typical OLED may include layers of organic material situated between two electrodes that are all deposited on a substrate in a manner to form a matrix display panel having pixels that may be individually energized. The OLED is generally placed between two glass panels, and the edges of the glass panels are sealed to encapsulate the OLED therein. 
         [0005]    The OLED industry, as well as other industries that utilize substrate processing techniques, encapsulate moisture-sensitive devices to protect them from ambient moisture exposure. A thin conformal layer of material has been proposed as a means of reducing Water Vapor Transmission Rate (WVTR) through encapsulation layer(s). Currently, there are a number of commercial ways to encapsulate devices. Using an ALD process to cover a moisture-sensitive device is being considered to determine if the conformal nature of these coatings can provide a more effective moisture barrier than other coatings. 
         [0006]    ALD is based upon atomic layer epitaxy (ALE) and employs chemisorption techniques to deliver precursor molecules on a substrate surface in sequential cycles. The cycle exposes the substrate surface to a first precursor and then to a second precursor. Optionally, a purge gas may be introduced between introductions of the precursors. The first and second precursors react to form a product compound as a film on the substrate surface. The cycle is repeated to form the layer to a desired thickness. 
         [0007]    One method of performing ALD is by Time-Separated (TS) pulses of precursor gases. TS-ALD has several advantages over other methods, however one drawback of TS-ALD is that every surface (e.g., the interior of the chamber) exposed to the precursors will be coated with deposition. If these deposits are not removed periodically, the deposits will tend to flake and peel off eventually, leading to particulates ending up on the substrate and hence degraded moisture barrier performance of the deposited layer. If there is no effective way to clean the undesired deposits from the chamber surfaces in situ, then those chamber surfaces must be removed for cleaning “off-line”. If the chamber has to be opened to accomplish removing and replacing chamber surfaces for cleaning, then vacuum has to be broken in the chamber (e.g., the chamber is brought to atmospheric pressure) and this breaking of vacuum will lead to excessive chamber down-time. 
         [0008]    There is a need, therefore, for a processing chamber allowing for removal and cleaning of the main key elements of the chamber which will accumulate extraneous deposits with minimal down-time. 
       SUMMARY OF THE INVENTION 
       [0009]    A chamber for performing an ALD process is provided. The chamber generally includes a gas distribution plate, a substrate support disposed in the chamber opposite the gas distribution plate, and at least one gas distribution plate actuator capable of moving the gas distribution plate relative to the substrate support. 
         [0010]    In another embodiment, a processing system for performing atomic layer deposition (ALD) is provided. The processing system generally includes an ALD processing chamber, wherein pressure within the ALD processing chamber is maintained at 1 torr or less and the ALD processing chamber has a first slit valve opening configured to permit passage of ALD process tools therethrough. The processing system further includes a first slit valve operable to open and close the first slit valve opening of the ALD processing chamber, wherein the first slit valve is operable to make an air-tight seal when closed, and a transfer chamber having a first slit valve opening configured to permit passage of ALD process tools therethrough and aligned to the first slit valve opening of the ALD processing chamber. 
         [0011]    In another embodiment, a method for replacing first process tools in an atomic layer deposition (ALD) chamber is provided. The method generally includes maintaining a pressure of 1 torr or less within the ALD chamber, opening a slit valve in the ALD chamber connected with a transfer chamber, moving the first process tools from the ALD chamber through the slit valve to the transfer chamber, and moving second process tools from the transfer chamber through the slit valve into the ALD chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
           [0013]      FIG. 1  illustrates an exemplary processing system, according to certain aspects of the present disclosure. 
           [0014]      FIG. 2  illustrates an exemplary chamber for ALD, according to certain aspects of the present disclosure. 
           [0015]      FIG. 3  illustrates an exemplary chamber for ALD, with components in a position in preparation for cleaning, according to certain aspects of the present disclosure. 
           [0016]      FIG. 4  illustrates an exemplary chamber for ALD, with components in a position in preparation for cleaning, according to certain aspects of the present disclosure. 
           [0017]      FIG. 5  illustrates an exemplary chamber for ALD, with components in a position in preparation for cleaning, according to certain aspects of the present disclosure. 
           [0018]      FIG. 6  illustrates an exemplary chamber for ALD, with components in a position in preparation for cleaning, according to certain aspects of the present disclosure. 
       
    
    
       [0019]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
       DETAILED DESCRIPTION 
       [0020]    Embodiments of the present disclosure include a processing system that is operable to deposit a plurality of layers on a substrate, the plurality of layers capable of acting as an encapsulation layer on an OLED formed on the substrate. The system includes a plurality of processing chambers, with each processing chamber operable to deposit one or more of the plurality of layers. The processing system further includes at least one transfer chamber and at least one load-lock chamber. The at least one transfer chamber enables transfer of substrates between the plurality of processing chambers without breaking vacuum in the processing system. The at least one load-lock chamber enables loading and removal of substrates from the processing system without breaking vacuum in the processing system. The processing system further includes a mask chamber that enables loading and removal of masks used in the processing chambers without breaking vacuum in the processing system. 
         [0021]    Embodiments of the disclosure include chemical vapor deposition (CVD) processing chambers that are operable to align a mask with respect to a substrate, position the mask on the substrate, and perform CVD to deposit an encapsulation layer on an OLED formed on the substrate. The CVD process performed in the CVD processing chambers may be plasma-enhanced CVD (PECVD), but the embodiments described herein may be used with other types of processing chambers and are not limited to use with PECVD processing chambers. The encapsulation layers deposited by the CVD processing chambers may comprise silicon nitride SiN, but the embodiments described herein may be used with other types of processing chambers and are not limited to use with SiN CVD processing chambers. 
         [0022]    Embodiments of the disclosure include an ALD processing chamber that is operable to align a mask with respect to a substrate, position the mask on the substrate, and perform ALD to deposit an encapsulation layer on an OLED formed on the substrate. The ALD process performed in the ALD processing chamber may be TS-ALD, but the embodiments described herein may be used with other types of processing chambers and are not limited to use with TS-ALD processing chambers. The encapsulation layers deposited by the ALD processing chambers may comprise aluminum oxide Al 2 O 3 , but the embodiments described herein may be used with other types of processing chambers and are not limited to use with SiN CVD processing chambers. 
         [0023]    The embodiments described herein may be used with other types of deposition processes and are not limited to use for encapsulating OLEDs formed on substrates. The embodiments described herein may be used with various types, shapes, and sizes of masks and substrates. 
         [0024]    The substrate is not limited to any particular size or shape. In one aspect, the term “substrate” refers to any polygonal, squared, rectangular, curved or otherwise non-circular workpiece, such as a glass substrate used in the fabrication of flat panel displays, for example. 
         [0025]    In the description that follows, the terms “gas” and “gases” are used interchangeably, unless otherwise noted, and refer to one or more precursors, reactants, catalysts, carrier gases, purge gases, cleaning gases, effluent, combinations thereof, as well as any other fluid. 
         [0026]      FIG. 1  is a cross sectional top view showing an illustrative processing system  100 , according to one embodiment of the present disclosure. The processing system  100  includes a load-lock chamber  104 , a transfer chamber  106 , a handling (e.g., tool and material handling) robot  108  within the transfer chamber  106 , a first CVD processing chamber  110 , a second CVD processing chamber  112 , a control station  114 , an ALD processing chamber  116 , and a mask chamber  118 . The first CVD processing chamber  110 , second CVD processing chamber  112 , ALD processing chamber  116 , and each chamber&#39;s associated hardware are preferably formed from one or more process-compatible materials, such as aluminum, anodized aluminum, nickel plated aluminum, stainless steel, quartz, and combinations and alloys thereof, for example. The first CVD processing chamber  110 , second CVD processing chamber  112 , and ALD processing chamber  116  may be round, rectangular, or another shape, as required by the shape of the substrate to be coated and other processing requirements. 
         [0027]    The transfer chamber  106  includes slit valve openings  121 ,  123 ,  125 ,  127 ,  129  in sidewalls adjacent to the load-lock chamber  104 , first CVD processing chamber  110 , second CVD processing chamber  112 , ALD processing chamber  116 , and mask chamber  118 . The handling robot  108  is positioned and configured to be capable of inserting one or more tools (e.g., substrate handling blades) through each of the slit valve openings  121 ,  123 ,  125 ,  127 ,  129  and into the adjacent chamber. That is, the handling robot can insert tools into the load-lock chamber  104 , the first CVD processing chamber  110 , the second CVD processing chamber  112 , the ALD processing chamber  116 , and the mask chamber  118  via slit valve openings  121 ,  123 ,  125 ,  127 ,  129  in the walls of the transfer chamber  106  adjacent to each of the other chambers. The slit valve openings  121 ,  123 ,  125 ,  127 ,  129  are selectively opened and closed with slit valves  120 ,  122 ,  124 ,  126 ,  128  to allow access to the interiors of the adjacent chambers when a substrate, tool, or other item is to be inserted or removed from one of the adjacent chambers. 
         [0028]    The transfer chamber  106 , load-lock chamber  104 , first CVD processing chamber  110 , second CVD processing chamber  112 , ALD processing chamber  116 , and mask chamber  118  include one or more apertures (not shown) that are in fluid communication with a vacuum system (e.g., a vacuum pump). The apertures provide an egress for the gases within the various chambers. In some embodiments, the chambers are each connected to a separate and independent vacuum system. In still other embodiments, some of the chambers share a vacuum system, while the other chambers have separate and independent vacuum systems. The vacuum systems can include vacuum pumps (not shown) and throttle valves (not shown) to regulate flows of gases through the various chambers. 
         [0029]    Masks, mask frames, and other items placed within the first CVD chamber  110 , second CVD chamber  112 , and ALD processing chamber  116 , other than substrates, may be referred to as a “process kit.” Process kit items may be removed from the processing chambers for cleaning or replacement. The transfer chamber  106 , mask chamber  118 , first CVD processing chamber  110 , second CVD processing chamber  112 , and ALD processing chamber  116  are sized and shaped to allow the transfer of masks, mask frames, and other process kit items between them. That is, the transfer chamber  106 , mask chamber  118 , first CVD processing chamber  110 , second CVD processing chamber  112 , and ALD processing chamber  116  are sized and shaped such that any process kit item can be completely contained within any one of them with all of the slit valve openings  121 ,  123 ,  125 ,  127 ,  129  closed by each slit valve opening&#39;s  121 ,  123 ,  125 ,  127 ,  129  corresponding slit valve  120 ,  122 ,  124 ,  126 ,  128 . Thus, process kit items may be removed and replaced without breaking vacuum of the processing system, as the mask chamber  118  acts as an airlock, allowing process kit items to be removed from the processing system without breaking vacuum in any of the chambers other than the mask chamber. Furthermore, the slit valve opening  129  between the transfer chamber  106  and the mask chamber  118 , the slit valve openings  123 ,  125  between the transfer chamber  106  and the CVD processing chambers  110 ,  112 , and the slit valve opening  127  between the transfer chamber  106  and the ALD processing chamber  116  are all sized and shaped to allow the transfer of process kit items between the transfer chamber  106  and the mask chamber  118 , CVD processing chambers  110 ,  112 , and ALD processing chamber  116 . 
         [0030]    The mask chamber  118  has a door  130  and doorway  131  on the side of the mask chamber  118  opposite the slit valve opening  129  of the transfer chamber  106 . The doorway is sized and shaped to allow the transfer of masks and other process tools into and out to the mask chamber  118 . The door  130  is capable of forming an air-tight seal over the doorway  131  when closed. The mask chamber  118  is sized and shaped to allow any process kit item to be completely contained within the mask chamber  118  with both the door  130  closed and the slit valve  128  leading to the transfer chamber  106  closed. That is, the mask chamber  118  is sized and shaped such that any process kit item can be moved from the transfer chamber  106  into the mask chamber  118  and the slit valve  128  can be closed without the door  130  of the mask chamber  118  being opened. 
         [0031]    For simplicity and ease of description, an exemplary coating process performed within the processing system  100  will now be described. The exemplary coating process is controlled by a process controller, which may be a computer or system of computers that may be located at the control station  114 . 
         [0032]    Referring to  FIG. 1 , the exemplary processing of a substrate optionally begins with the handling robot  108  retrieving a mask from the mask chamber  118  and placing the mask in the ALD processing chamber  116 . Placing a mask in the ALD processing chamber  116  is optional because a mask may be left in the ALD processing chamber  116  from earlier processing, and the same mask may be used in processing multiple substrates. Similarly, the handling robot  108  may optionally retrieve other masks from the mask chamber  118  and place the masks in the first and second CVD processing chambers  110  and  112 . In placing masks within the first and second CVD processing chambers  110 ,  112  and the ALD processing chamber  116 , the appropriate slit valves  122 ,  124 ,  126 ,  128  between the chambers may be opened and closed. 
         [0033]    Next, the handling robot  108  retrieves a substrate from the load-lock  104  and places the substrate in the first CVD processing chamber  110 . The process controller controls valves, actuators, and other components of the processing chamber to perform the CVD processing. The process controller causes the slit valve  122  to be closed, isolating the first CVD processing chamber  110  from the transfer chamber  106 . The process controller also causes a substrate support member, or susceptor, to position the substrate for CVD processing. If the mask was not placed into the correct processing position by the handling robot, then the process controller may activate one or more actuators to position the mask. Alternatively or additionally, the susceptor may also position the mask for processing. The mask is used to mask off certain areas of the substrate and prevent deposition from occurring on those areas of the substrate. 
         [0034]    The process controller now activates valves to start the flow of precursor and other gases into the first CVD processing chamber. The precursor gases may include silane SiH 4 , for example. The process controller controls heaters, plasma discharge components, and the flow of gases to cause the CVD process to occur and deposit layers of materials on the substrate. In one embodiment, the deposited layer may be silicon nitride (SiN), although embodiments of the disclosure are not limited to SiN. Other suitable materials include SiO, SiON, and combinations thereof. As noted above, embodiments of the disclosure may also be used to perform PECVD. The CVD process in the exemplary processing of the substrate is continued until the deposited layer reaches the desired thickness. In one exemplary embodiment, the desired thickness is 5000 to 10000 Angstroms (500 to 1000 nm). 
         [0035]    When the CVD process in the first CVD processing chamber  110  is complete, the process controller causes the first CVD processing chamber  110  to be evacuated and then controls the susceptor to lower the substrate to a transfer position. The process controller also causes the slit valve  122  between the first CVD processing chamber  110  and the transfer chamber  106  to be opened and then directs the handling robot  108  to retrieve the substrate from the first CVD processing chamber  110 . The process controller then causes the slit valve  122  between first CVD processing chamber  110  and the transfer chamber  106  to be closed. 
         [0036]    Next, the process controller causes the slit valve  126  between the transfer chamber  106  and the ALD processing chamber  116  to be opened. The handling robot  108  places the substrate in the ALD processing chamber  116 , and the process controller causes the slit valve  126  between the transfer chamber  106  and the ALD processing chamber  116  to be closed. The process controller also causes a substrate support member, or susceptor, to position the substrate for ALD processing. If the mask was not placed into the correct processing position by the handling robot, then the process controller may activate one or more actuators to position the mask. Alternatively or additionally, the susceptor may position the mask for processing. The mask is used to mask off certain areas of the substrate and prevent deposition from occurring on those areas of the substrate. 
         [0037]    The process controller now activates valves to start the flow of precursor and other gases into the ALD processing chamber  116 . The particular gas or gases that are used depend upon the process or processes to be performed. The gases can include trimethylaluminium (CH 3 ) 3 Al (TMA), nitrogen N 2 , and oxygen O 2 , however, the gases are not so limited and may include one or more precursors, reductants, catalysts, carriers, purge gases, cleaning gases, or any mixture or combination thereof. The gases may be introduced into the ALD processing chamber  116  from one side and flow across the substrate. Depending on requirements of the processing to be performed, the process controller may control valves such that only one gas is introduced into the ALD processing chamber  116  at any particular instant of time. 
         [0038]    The process controller also controls a power source capable of activating the gases into reactive species and maintaining the plasma of reactive species to cause the reactive species to react with and coat the substrate. For example, radio frequency (RF) or microwave (MW) based power discharge techniques may be used. The activation may also be generated by a thermally based technique, a gas breakdown technique, a high intensity light source (e.g., UV energy), or exposure to an x-ray source. In the exemplary process, oxygen is activated into a plasma, and the plasma reacts with and deposits a layer of oxygen on the substrate. The process controller then causes TMA to flow across the substrate, and the TMA reacts with the layer of oxygen on the substrate, forming a layer of aluminum oxide on the substrate. The process controller causes repetition of the steps of flowing oxygen, activating oxygen into a plasma, and flowing TMA to form additional layers on the substrate. The process controller continues repeating the described steps until the deposited layer of aluminum oxide is the desired thickness. In one exemplary embodiment, the desired thickness is 500 to 700 Angstroms (fifty to seventy nm). 
         [0039]    When the ALD process in the ALD processing chamber  116  is complete, the process controller causes the ALD processing chamber  116  to be evacuated and then controls the susceptor to lower the substrate to a transfer position. The process controller also causes the slit valve  126  between the ALD processing chamber  116  and the transfer chamber  106  to be opened and then directs the handling robot  108  to retrieve the substrate from the ALD processing chamber  116 . The process controller then causes the slit valve  126  between ALD processing chamber  116  and the transfer chamber  106  to be closed. 
         [0040]    Still referring to  FIG. 1 , next, the process controller causes the slit valve  124  between the transfer chamber  106  and the second CVD processing chamber  112  to be opened. The handling robot  108  places the substrate in the second CVD processing chamber  112 , and the process controller causes the slit valve  124  between the transfer chamber  106  and the second CVD processing chamber  112  to be closed. Processing in the second CVD processing chamber  112  is similar to the processing in the first CVD processing chamber  110  described above. In the exemplary processing of the substrate, the CVD process performed in the second CVD processing chamber  112  is continued until the deposited layer reaches the desired thickness. In one exemplary embodiment, the desired thickness is 5000 to 10000 Angstroms (500 to 1000 nm). 
         [0041]    Thus, when the process in the second CVD processing chamber  112  is complete, the substrate will be coated with a first layer of SiN that is 5000 to 10000 Angstroms thick, a layer of Al 2 O 3  that is 500 to 700 Angstroms thick, and a second layer of SiN that is 5000 to 10000 Angstroms thick. The layer of Al 2 O 3  is believed to lower the water vapor transfer rate through the encapsulation layer, as compared to SiN alone, thus improving the reliability of the encapsulation, as compared to encapsulating with SiN alone. 
         [0042]    In the exemplary process described above with reference to  FIG. 1 , each of the CVD processing chambers  110 ,  112  and the ALD processing chamber  116  is loaded with a mask. Alternatively, the processing system  100  may perform a process wherein a mask moves with a substrate from processing chamber to processing chamber. That is, in a second exemplary process, a substrate and mask are placed (simultaneously or individually) in the first CVD processing chamber  110 , and the slit valve  122  between the transfer chamber  106  and the first processing chamber  110  is closed. A CVD process is then performed on the substrate. The substrate and mask are then moved (simultaneously or individually) into the ALD processing chamber  116 , and the slit valve  126  between the transfer chamber and the ALD processing chamber  116  is closed. An ALD process is then performed on the substrate. The substrate and mask are then moved (simultaneously or individually) into the second CVD processing chamber  112 . A CVD process is then performed on the substrate, and the substrate and mask are then removed from the second CVD processing chamber  112 . The substrate may be removed from the processing system  100 , if complete, and the mask may be used for processing a new substrate or removed from the processing system  100  for cleaning, for example. 
         [0043]      FIG. 2  is a partial cross sectional view showing an illustrative ALD processing chamber  200  with components in position for processing. The ALD processing chamber shown in  FIG. 2  is highly similar to the ALD processing chamber  116  shown in  FIG. 1 . In one embodiment, the processing chamber  200  includes a chamber body  202 , a lid assembly  204 , and a substrate support assembly  206 . The lid assembly  204  is disposed at an upper end of the chamber body  202 , and the substrate support assembly  206  is at least partially disposed within the chamber body  202 . 
         [0044]    The chamber body  202  includes a slit valve opening  208  formed in a sidewall thereof to provide access to the interior of the processing chamber  100 . As described above with reference to  FIG. 1 , the slit valve opening  208  is selectively opened and closed to allow access to the interior of the chamber body  202  by a handling robot (see  FIG. 1 ). 
         [0045]    In one or more embodiments, the chamber body  202  includes one or more apertures  210  that are in fluid communication with a vacuum system (e.g., a vacuum pump). The apertures provide an egress for the gases within the processing chamber. The vacuum system is controlled by a process controller to maintain a pressure within the ALD processing chamber suitable for the ALD process. In one embodiment of the present disclosure, the pressure in the ALD processing chamber is maintained at a pressure of 500 to 700 mTorr. 
         [0046]    The processing chamber  200  may include a valve block assembly  212 . The valve block assembly comprises a set of valves and controls the flow of the various gases into the processing chamber  200 . The lid assembly  204  may comprise a plenum  240  above the gas distribution plate or showerhead  242 . Process gases, oxygen for example, may flow into the plenum  240  before flowing through the showerhead  242  into the processing chamber  200 . The showerhead  242  may comprise any number of openings (i.e., holes) of consistent or varying sizes, according to the processing requirements. Other precursor gases, trimethylaluminium and nitrogen for example, may flow through and be distributed from the central opening  216 . 
         [0047]    Still referring to  FIG. 2 , the lid assembly  204  can further act as an electrode to generate a plasma of reactive species within the lid assembly  204 . In one or more embodiments, the electrode is coupled to a power source (e.g., an RF generator)  218  while a gas delivery assembly is connected to ground (i.e., the gas delivery assembly serves as an electrode). Accordingly, a plasma of one or more process gases can be generated between the gas delivery assembly and a substrate support member or susceptor  222 . Additionally or alternatively, the plasma may be struck and contained between the susceptor  222  and the showerhead  242 . 
         [0048]    Any power source capable of activating the gases into reactive species and maintaining the plasma of reactive species may be used. For example, radio frequency (RF) or microwave (MW) based power discharge techniques may be used. The activation may also be generated by a thermally based technique, a gas breakdown technique, a high intensity light source (e.g., UV energy), or exposure to an x-ray source. 
         [0049]    Still referring to  FIG. 2 , the substrate support assembly  206  can be at least partially disposed within the chamber body  202 . The substrate support assembly can include a substrate support member or susceptor  222  to support a substrate  232  for processing within the chamber body. The susceptor  222  can be coupled to a substrate lift mechanism (not shown) through a shaft  224  or shafts  224  which extend through one or more openings  226  formed in a bottom surface of the chamber body. The substrate lift mechanism can be flexibly sealed to the chamber body by a bellows (not shown) that prevents vacuum leakage from around the shafts. The substrate lift mechanism allows the susceptor to be moved vertically within the chamber body between a process position, as shown, and lower robot entry, mask removal, showerhead removal, and substrate transfer positions. The susceptor is in the substrate transfer position when the upper surface of the susceptor is slightly below the opening of the slit valve formed in a sidewall of the chamber body. 
         [0050]    A mask  230  may be positioned over the substrate  232  during processing to control the locations of the deposition, depending on production requirements. The processing chamber  200  may further comprise a plurality of mask alignment shafts  228 . When the substrate support assembly  206  is lowered, the mask may come to rest on the mask alignment shafts, as shown in  FIGS. 5 and 6 . The mask alignment shafts may be coupled to a mask lift mechanism (not shown), which may raise and lower the mask alignment shafts when the mask is removed or replaced (e.g., for cleaning or changing the mask). 
         [0051]    In one or more other embodiments, the susceptor  222  has a flat, rectangular surface or a substantially flat, rectangular surface, as required by the shape of the substrate and other processing requirements. In one or more embodiments, the substrate  232  may be secured to the susceptor using a vacuum chuck (not shown), an electrostatic chuck (not shown), or a mechanical clamp (not shown). 
         [0052]    Still referring to  FIG. 2 , the susceptor  222  can include one or more bores  234  through the susceptor to accommodate one or more lift pins  236 . Each lift pin is typically constructed of ceramic or ceramic-containing materials, and is used for substrate-handling and transport. Each lift pin  236  is mounted so that they may slide freely within a bore  234 . In one aspect, each bore  234  is lined with a ceramic sleeve to help the lift pins  236  to freely slide. Each lift pin  236  is moveable within its respective bore  234  by contacting the chamber body  202  when the support assembly  206  is lowered, as shown in  FIGS. 4-6 . The support assembly  206  is movable such that the upper surface of the lift pin  236  can be located above the substrate support surface of the susceptor  222  when the support assembly is in a lower position. Conversely, the upper surface of the lift pins  236  is located below the upper surface of the susceptor  222  when the support assembly is in a raised position. Thus, part of each lift pin  236  passes through a respective bore  234  in the susceptor  222  when the support assembly moves from a lower position to an upper position, and vice-versa. 
         [0053]    When contacting the chamber body  202 , the lift pins  236  push against a lower surface of the substrate  232 , lifting the substrate  232  off the susceptor  222 . Conversely, the susceptor  222  may raise the substrate  232  off of the lift pins  236 . The lift pins  236  can include enlarged upper ends or conical heads to prevent the lift pins  236  from falling out from the susceptor  222 . Other pin designs can also be utilized and are well known to those skilled in the art. 
         [0054]    In one embodiment, one or more of the lift pins  236  include a coating or an attachment disposed thereon that is made of a non-skid or highly frictional material to prevent the substrate  232  from sliding when supported thereon. A preferred material is a heat-resistant, polymeric material that does not scratch or otherwise damage the backside of the substrate  232 , which would create contaminants within the processing chamber  200 . 
         [0055]    Referring back to  FIG. 2 , the susceptor  222  can be moved vertically within the chamber body  202  so that a distance between the susceptor  222  and the showerhead  242  can be controlled. An optical or other sensor (not shown) can provide information concerning the position of the susceptor  222  within the chamber  200 . 
         [0056]    The processing chamber  200  may further comprise one or more showerhead actuators  238 . The showerhead actuators may be connected to the showerhead  242 . The showerhead actuators  238  may raise or lower the showerhead  242  for removal or replacement of the showerhead  242  (e.g., for cleaning or other purposes), as shown in  FIG. 6 . 
         [0057]    The process for removing the mask  230  and showerhead  242  from the processing chamber  200  for cleaning without taking the chamber off-line will now be described. Referring to  FIG. 2 , the processing chamber begins with the susceptor  222  in the process position. The removal process begins with lowering the substrate support assembly  206  by means of the substrate lift mechanism (not shown) lowering the shaft(s)  224 . The susceptor  222  lowers the mask  230  until the mask  230  contacts the mask alignment shafts  228 , which remain in a raised position, as illustrated in  FIG. 3 . The showerhead actuators  238  are not activated, and the showerhead remains in a process position. This may be described as the “mask drop position.” 
         [0058]      FIG. 4  illustrates the next step in the removal process. The substrate support assembly  206  continues lowering until it reaches its lowest position, as shown in  FIG. 4 . This may be known as the “robot entry position.” Mask  230  remains resting on mask alignment shafts  228 . A robot blade  402  or other robotic tool enters the processing chamber  200  through the slit valve opening  208 , and is positioned below the mask by the handling robot (see  FIG. 1 ). The robot blade has a plurality of slots (not shown) in it, allowing it to reach past the mask alignment shafts and lift pins  236 . That is, the robot blade or other robotic tool has slots that may be aligned with the mask alignment shafts and lift pins so that the robot blade or other robotic tool can be inserted in the processing chamber below the mask without impacting the mask alignment shafts and lift pins. 
         [0059]      FIG. 5  illustrates the position of the items in the processing chamber  200  immediately before removal of the mask  230  from the chamber. The mask alignment shafts  228  are lowered by the mask lift mechanism (not shown). When the mask alignment shafts are low enough, the mask contacts the robot blade  402 . The mask alignment shafts continue withdrawing until they are completely clear of the mask. This may be known as the “mask removal position.” At this point, the handling robot (see  FIG. 1 ) withdraws the robot blade and the mask. The handling robot may place the mask within the mask chamber (see  FIG. 1 ) for removal of the mask from the processing system. The mask can then be removed from the mask chamber for cleaning without breaking vacuum of the other chambers of the processing system. 
         [0060]      FIG. 6  illustrates the final position of the items in the processing chamber  200  before removal of the showerhead  242 . After removal of the mask (not shown in  FIG. 6 ), the handling robot (see  FIG. 1 ) introduces a robot blade  602  or other robotic tool through the slit valve opening  208 . The robot blade  602  may be the same robot blade  402  shown in  FIGS. 4 and 5 , but this is not required. The showerhead actuators  238  then activate, lowering the showerhead onto the robot blade. After lowering the showerhead onto the robot blade, the actuators disconnect from the showerhead by means of couplings (not shown). The couplings may be electrostatic or mechanical couplings, for example. This may be known as the “showerhead removal position.” After the showerhead is resting on the robot blade and the actuators have disconnected from the showerhead, the handling robot may withdraw the robot blade and the showerhead (e.g., for cleaning). The handling robot may place the showerhead within the mask chamber (see  FIG. 1 ) for removal of the showerhead from the processing system. Similar to the movement of the mask described with reference to  FIG. 5 , the showerhead can be removed from the mask chamber for cleaning without breaking vacuum of the other chambers of the processing system. 
         [0061]    A processing system  100  as described above, allows removal of a mask, showerhead, and other process tools from the processing system without breaking vacuum on several of the processing chambers. Thus, the process tools, which can accumulate unwanted deposits from being exposed to the CVD and/or ALD processes, can be removed from the processing chambers for cleaning while the processing chambers remain at process pressures (e.g., 500 to 700 mTorr). Other process tools can also be placed in the processing chambers without breaking vacuum in the processing chambers. Because the process tools can be replaced without breaking vacuum in the processing chambers, processing can continue after process tool replacement more quickly in the processing chambers as compared to processing chambers which cannot have their process tools replaced without breaking vacuum. Processing can continue more quickly after process tool replacement because the processing chambers are already evacuated and do not need to be pumped down from atmospheric pressure (e.g., 760 Torr) after process tool replacement. In addition, there is a reduced chance of contamination of the processing chambers during process tool replacement, as the processing chambers are not exposed to atmospheric air and other contaminants during the process tool replacement. 
         [0062]    The process controller described above with reference to  FIG. 1  can operate under the control of a computer program stored on a hard disk drive of a computer. For example, the computer program can dictate the process sequencing and timing, mixture of gases, chamber pressures, RF power levels, susceptor positioning, slit valve opening and closing, and other parameters of a particular process. 
         [0063]    To provide a better understanding of the foregoing discussion, the above non-limiting examples are offered. Although the examples may be directed to specific embodiments, the examples should not be interpreted as limiting the invention in any specific respect. 
         [0064]    Unless otherwise indicated, all numbers expressing quantities of ingredients, properties, reaction conditions, and so forth, used in the specification and claims are to be understood as approximations. These approximations are based on the desired properties sought to be obtained by the present invention, and the error of measurement, and should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Further, any of the quantities expressed herein, including temperature, pressure, spacing, molar ratios, flow rates, and so on, can be further optimized to achieve the desired layer and particle performance. 
         [0065]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.