Abstract:
A multi-workpiece chamber includes at least two processing stations, for exposing workpieces to a treatment process. A partition cooperates with the chamber such that the partition is disengagably removable from the chamber and re-engagable with the chamber for selectively dividing the processing stations. The partition is configured to provide for non-line-of-sight travel of certain ones of the process related products between the processing stations. An exhaust arrangement divides exhaust flow into at least two approximately equal exhaust flow portions that leave the multi-workpiece chamber in a way which enhances uniformity of the treatment process for the stations. A partition configuration is described including a partition portion between the stations and a baffle portion extending into an exhaust arrangement. A modified partition arrangement is provided for use in establishing a modified exchange characteristic of the process related products.

Description:
This application is a continuation application of U.S. patent application Ser. No. 10/828,614 filed Apr. 21, 2004 now U.S. Pat. No. 7,276,122, the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is related generally to the field of workpiece processing such as, for example, processing semiconductor wafers and, more particularly, to a multi-workpiece processing chamber and its method of use. 
     A number of processing systems, currently used in the production of semiconductor wafers, are capable of processing more than one wafer at a time for purposes of enhancing system throughput. It has been asserted in the prior art, however, that a single-wafer process chamber provides more uniform process results when compared to multi-wafer processing chamber configurations. Presumably, this degradation in “across-wafer” and “station-to-station” uniformity is thought to be directly attributable to communication between adjacent wafer processing stations within a shared process chamber and environment. 
     Process uniformity, however, is of increasing concern, particularly in view of an industry emphasis on ever-decreasing device feature sizes. One example, attempting to provide a compromise between the asserted contamination problem that is associated with batch processing in a shared process environment and limited throughput in the use of single-wafer process chamber, is seen in U.S. Pat. No. 5,855,681 (hereinafter the &#39;681 patent). The latter adopts the use of “tandem” single wafer processing chambers, having processing regions that are described as being separate from one another (see col. 4, ln. 37-40). A single chamber body is used to define these separate processing regions. The processing region defined by each tandem chamber is deemed by the patent as isolatable from the processing region of the other tandem chamber by virtue of limiting communication between the adjacent processing regions only to that which selectively occurs through an exhaust system. Such selective communication would presumably be controlled based on the pumping status of the vacuum pumping system. Otherwise, the tandem chambers appear to function, from a process standpoint, in a way which is essentially the same as a pair of separate single-wafer processing chambers (see, for example, col. 2, ln. 54-56). In this regard, the system provides for multiple, isolated processes to be performed concurrently in at least two regions (see col. 4, ln. 44-51), which reasonably suggests that a first process can be performed in one processing region of a tandem chamber while a second, different process is performed in the other processing region of that same tandem chamber. 
     While there may be advantages associated with the asserted capabilities of the separate, tandem chambers of the &#39;861 patent in providing for simultaneously executing different processes in each chamber, it is a concern that there are many circumstances in which such capability is not necessary. That is, there are many instances in which it is advantageous, at least from a throughput standpoint, to perform the same process at both processing stations, without a need for providing the additional capability to practice different processes. It is a further concern that certain aspects of the configuration for the tandem chamber of the &#39;861 patent such as, for example, its exhaust configuration, are quite complex. This exhaust system is seen in FIG. 21 of the patent wherein a pair of individual exhaust conduits 621 merge into a common exhaust channel 619. It is considered that the use of this complex exhaust system adds considerable expense to the fabrication of the tandem chamber arrangement. Still further problems could be introduced if there is any tendency for contaminants to build up in exhaust channels 621, leading to different pressures in one chamber with respect to the other. Likewise, other features, which result in the capability to practice different processes, are considered to add expense to the cost of the system in order to achieve a level of region-to-region process isolation which may never be needed, in view of a particular end user&#39;s needs. 
     Referring to  FIG. 1 , one prior art process chamber configuration, that has been found to be useful and which avoids the aforedescribed concerns with respect to the &#39;681 patent, is generally indicated by the reference number  10 . Chamber  10  includes a first wafer pedestal  12  and a second wafer pedestal  14 , each of which is configured for supporting a wafer (not shown) thereon. 
     Referring to  FIG. 2  in conjunction with  FIG. 1 , chamber  10  includes a chamber base  20  that is best seen in the cross-sectional view of  FIG. 2  and is integrally formed with an arrangement of sidewalls  22 . Chamber base  20  defines a single exhaust port  24  which serves the entire chamber interior. A single chamber lid (not shown) is hinged to chamber  10  along one of its peripheral edges and seals against an O-ring  28  ( FIG. 1 ) that is supported by sidewall arrangement  22 . A partition  30  is integrally formed with sidewalls  22  and with chamber base  20  so as to extend between a lengthwise pair of the sidewalls, across the entrance leading into exhaust port  24 . A notch  32  is defined in partition  30  so as to provide for flow communication between opposing sides of the partition. A pump spool  34  is attached to chamber base  20  and defines an exhaust channel  36  that is aligned with exhaust port  24 . 
     Referring to  FIG. 2 , partition  30  does not seal against chamber lid  26 . In this regard, a gap (not shown) is formed between an upper edge of the partition and the chamber lid so that the upper edge confronts the chamber lid, but does not contact it. Such potential rubbing contact is undesirable at least for the reason that particle generation would occur in a way that can adversely affect a process that is being executed at either of the wafer pedestals in the chamber. Partition  30  has a thickness that is on the order of ¼ or less of the thickness of the chamber sidewalls. Accordingly, the partition is not intended to support a pressure differential from one side to the other, since continuous pressure equalization occurs very rapidly through notch  32 . It should be appreciated that even slight pressure differences from one processing station to the other can produce significant differences in on-wafer process results. 
     Referring again to  FIG. 1 , chamber  10  is considered to comprise a batch processing system, since no capability is provided for performing a different process at wafer pedestal  12  than the process which is preformed at wafer pedestal  14 . That is, either the same process should be performed at both pedestals or one of the pedestals should be inactive. This system will not accommodate performing different processes at the pedestals, since some degree of cross-contamination can occur. At the same time, however, it is recognized that this limited level of cross-contamination may be insignificant when the same process is performed at multiple stations that are within a common process chamber and environment. 
     Of course, some process constraints can be controlled individually for each wafer pedestal, as has long been practiced. For example, variations in gas mixtures intended to further enhance process uniformity can be provided using separate showerheads (not shown), one of which is provided for each wafer pedestal. 
     The chamber of  FIGS. 1 and 2  has provided more than acceptable process results while avoiding the need to use completely isolated single wafer process environments, as is taught by the &#39;228 patent. In this regard, the present invention provides more than acceptable process results in a multi-wafer chamber maintaining a limited communication between adjacent processing regions, which continues to overcome the aforementioned concerns associated with the &#39;228 patent, while providing still further advantages over all prior art of which Applicant is aware, as will be described in detail hereinafter. 
     SUMMARY OF THE INVENTION 
     In a system for processing a workpiece, an apparatus and method are described. In one aspect of the present invention, a multi-workpiece chamber is provided including at least two processing stations, each of which is configured for exposing one of the workpieces to the treatment process. A partition is configured to cooperate with the chamber such that the partition is disengagably removable from the chamber and, thereafter, re-engagable with the chamber for selectively dividing the processing stations from one another. 
     In another aspect of the present invention, a multi-workpiece chamber is provided including at least two processing stations, each of which is configured for exposing one of the workpieces to a treatment process. A partition arrangement is positioned between the processing stations, supported by the multi-workpiece chamber, and configured to cooperate with the chamber to provide only for non-line-of-sight travel of certain ones of the process related products between the processing stations, whereby the certain ones of the process related products, that are only able to travel line-of-sight are, therefore, unable to move between the processing stations when the partition is engaged with the chamber. 
     In still another aspect of the present invention, a multi-workpiece chamber includes at least two processing stations, each of which is configured for exposing one of the workpieces to a treatment process, and which defines an exhaust port that is positioned at least generally between and equidistant from each of the processing stations for use in evacuating the chamber in association with the treatment process. An exhaust arrangement is in flow communication with the exhaust port for conducting an exhaust flow from the multi-workpiece chamber. The exhaust arrangement includes a flow divider arrangement which divides the exhaust flow into at least two approximately equal exhaust flow portions that leave the multi-workpiece chamber in a way which enhances uniformity of the treatment process for the first and second workpiece stations. In one feature, the exhaust flow portions are at least approximately equal to one another. 
     In yet another aspect of the present invention, a multi-workpiece chamber includes at least two processing stations, each of which is configured for exposing one of the workpieces to a treatment process and which defines an exhaust port that is at least generally between and equidistant from each of the processing stations and including an exhaust arrangement that is connected to the exhaust port to define an exhaust channel to support an exhaust flow for use in evacuating the chamber. A partition configuration is configured to cooperate with the chamber such that the partition configuration is disengagably removable form the chamber and, thereafter, re-engagable with the chamber. The partition configuration including a partition portion that is positioned between the processing stations, when engaged with the chamber, and including a baffle portion supported by the partition portion and extending outward from the exhaust port and into the exhaust channel in a way which divides the exhaust flow into at least two exhaust flow portions that leave the multi-workpiece chamber. 
     In a continuing aspect of the present invention, a multi-workpiece chamber includes at least two processing stations, each of which is configured for exposing one of the workpieces to the treatment process. A first partition arrangement is selectively removable from the multi-workpiece chamber and is positionable between the processing stations, supported by the multi-workpiece chamber, for establishing an exchange characteristic of the process related products between the processing stations when so positioned. At least one modified partition arrangement is provided for use in replacing the first partition arrangement to establish a modified exchange characteristic of the process related products between the processing stations. In one feature, the exchange characteristic relates to mobility of the process related products. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       The present invention may be understood by reference to the following detailed description taken in conjunction with the drawings briefly described below. 
         FIG. 1  is a diagrammatic perspective view of a prior-art processing chamber, shown here to illustrate details with respect to its structure. 
         FIG. 2  is a diagrammatic view, in elevation, shown here to illustrate details with respect to a partition that is used in the processing chamber of  FIG. 1 . 
         FIG. 3  is a diagrammatic view, in elevation, of a workpiece processing system that is produced in accordance with the present invention, shown here to illustrate its construction. 
         FIG. 4  is a diagrammatic perspective view of a processing chamber arrangement that is used in the system of  FIG. 3 , shown here to illustrate further details with respect to the structure of the chamber arrangement. 
         FIG. 5  is a diagrammatic enlarged cutaway perspective view of a partition arrangement and processing chamber, used in the system of the present invention, shown here to illustrate one configuration for disengageably installing the partition arrangement in the processing chamber. 
         FIG. 6  is a diagrammatic enlarged cutaway view, in cross-section, taken along a line  6 - 6 , as shown in  FIG. 5 , shown here to illustrate details with respect to cooperation between the partition arrangement and chamber sidewall with which it interfaces so as to define a circuitous gap between the partition arrangement and chamber sidewall, as well as details with respect to a passage arrangement that is defined by the chamber sidewall. 
         FIG. 7  is a diagrammatic enlarged cutaway view, in cross-section, taken at a point along an upper lengthwise margin of the partition arrangement and looking toward a rear sidewall of the processing chamber, shown here to illustrate details with respect to a cooperating configuration of the chamber lid and partition arrangement which defines a circuitous gap therebetween. 
         FIG. 8  is a diagrammatic cross-sectional view, in elevation, shown here to illustrate further details with respect to installation of the partition arrangement within the processing chamber and to illustrate the arrangement of a baffle within a pump spool forming part of the exhaust system from the processing chamber. 
         FIG. 9  is a diagrammatic plan view of the processing chamber having the processing chamber lid removed, shown here to illustrate further details with respect to installation of the partition arrangement, baffle and other features. 
         FIG. 10  is a diagrammatic partially cutaway perspective view of the processing system of  FIG. 3 , also having the chamber lid removed, shown here to illustrate still further details with respect to the partition arrangement installation features and the baffle. 
         FIG. 11  is a diagrammatic partially cutaway perspective view of the processing system of the present invention, shown here having a modified partition arrangement installed therein which includes a partition portion and a baffle portion. 
         FIG. 12  is an enlarged cross-sectional cutaway view, taken through the thickness of the partition arrangement at its lowermost edge and the baffle at its confronting, uppermost edge, showing an alternative configuration of its bottom edge and its relationship to a spool piece supported baffle. 
         FIGS. 13   a - d  are enlarged cross-sectional cutaway views, similar to the view of  FIG. 12 , taken through the thickness of the partition arrangement at its lowermost edge and the baffle at its confronting, uppermost edge, showing an number of alternative gap configurations. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the described embodiments will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein. It is noted that the drawings are not to scale and are diagrammatic in nature. Further, like reference numbers are applied to like components, whenever practical, throughout the present disclosure. Descriptive terminology such as, for example, up/down, right/left, front/rear and the like has been adopted for purposes of enhancing the reader&#39;s understanding, with respect to the various views provided in the figures, and is in no way intended as been limiting. 
       FIG. 3  is a diagrammatic view, in elevation, of a semiconductor processing system, generally indicated by the reference number  100 , according to one embodiment of the present invention. While system  100  represents one implementation that is useful in the practice of the present invention, it is to be understood that the present invention may be utilized in conjunction with a variety of alternative configurations and the presently illustrated implementation is not intended as being limiting. A processing chamber arrangement  102  forms part of system  100  and is illustrated having a front portion cut away in order to reveal the chamber interior configuration. Of course, there must be a provision for transferring workpieces into and out of processing chamber arrangement  102 , as will be further described below. 
     Still referring to  FIG. 3 , chamber arrangement  102  is made up of a chamber  104 , which may be referred to as a chamber bowl, and a chamber lid  106 . The latter may be hingedly attached to the chamber bowl. The chamber lid and chamber bowl cooperate to define a chamber interior or cavity  108  that is isolatable from ambient pressure. A first processing station  120  and a second processing station  122  are positioned in chamber interior  108 . For purposes of the present example, system  100  will be described in the context of removing a photoresist layer or pattern (not shown) from semiconductor, opto-electronic or flat panel display workpieces  130 , although one of ordinary skill in the art will appreciate that this system is readily useful in the application of other processes including, but not limited to various implementations of chemical vapor deposition, atomic layer deposition and plasma etch. Accordingly, for purposes of the present example, a pair of plasma sources, each individual one of which is indicated by the reference number  132 , is provided. For purposes of photoresist removal, inductively coupled plasma (ICP) sources, may be used such that one source is associated with each of the processing stations so as to generate a plasma  134  which is represented by a number of dashed lines. Other suitable plasma sources include, but are not limited to microwave sources, surface wave plasma sources, ECR plasma sources, and capacitively coupled (parallel plate) plasma sources. 
     Continuing with a description of  FIG. 3 , each workpiece  130  such as, for example, a semiconductor wafer is supported on a susceptor  136 . Each susceptor may be useful in heating the workpiece to a desired temperature. Any suitable type of susceptor may be used such as, for example, a suitable platen. Lift pins  138  are used to raise and lower each workpiece with respect to each of susceptors  136 . The lift pins are shown in a retracted position such that each workpiece is supported on one of the susceptors. While only two lift pins are illustrated, in the present figure, per susceptor for purposes of illustrative simplicity, a minimum of three lift pins is required per susceptor. Another part of system comprises an exhaust arrangement  140  that is used in producing a vacuum in chamber interior  18 . For this purpose, exhaust gas  142  flows in a direction indicated by arrows. Exhaust arrangement  140  includes, for example, a flanged pump spool  144 , which serves in the manner of a tailpiece, and which is attached to chamber bowl  104  in any suitable manner such as, for example, using a plurality of bolts (not shown). Sealing may be performed, for example, using an O-ring (not shown) between the flanged spool and chamber bowl. 
     Referring now to  FIG. 4 , further details of system  100  will now be described with regard to this perspective view. For purposes of clarity, chamber lid  106  ( FIG. 3 ) and associated sources  132 , which are supported by the chamber lid have not been shown. A front lengthwise sidewall  150   a  of chamber bowl  104  defines a pair of slit openings  152  through which wafers can be inserted and removed from the chamber for each one of the wafer susceptors. An O-ring  154  surrounds both of these slit openings for use in sealing against other components (not shown) such as, for example, a wafer transfer chamber, a description of which is beyond the scope of present application. An O-ring groove, indicated by the reference number  156  (also seen in  FIG. 3 ), is defined in upper ends of the chamber peripheral sidewalls for receiving an O-ring (not shown) that is used in sealing chamber lid  106  ( FIG. 3 ) against the chamber bowl. Another pair of slits, each of which is indicated by the reference number  158 , is used for process monitoring, in a rear lengthwise chamber sidewall  150   b.    
     Referring to  FIGS. 3 and 4 , chamber bowl  104  is configured to support a partition arrangement  160 . The partition arrangement includes a generally planar partition plate  162  having peripheral edge configurations that will be described in detail below. Partition plate  162  extends generally between processing stations  120  and  122  in a way which may serve to bisect processing chamber  104  and is held in position, proximate to its upper corners, using fasteners  164   a  and  164   b , as will be described. 
     Turning now to  FIGS. 5 and 6  in conjunction with  FIGS. 3 and 4 , further details will now be provided with regard to the way in which partition arrangement  160  is supported by the chamber bowl. It is noted that  FIG. 5  is an enlarged, partially cut away detail view, in perspective, illustrating the rear, upper corner of partition arrangement  160  as it cooperates with rear, lengthwise chamber sidewall  150   b .  FIG. 6  is an enlarged cross-sectional, partially cut away, detailed view taken generally along a line  6 - 6 , which is illustrated in  FIG. 5 . It is noted that  FIG. 6  further illustrates a portion of a chamber base  170 , immediately adjacent to an exhaust port  172  (only partially shown) that is defined in the chamber base. Like the front lengthwise chamber sidewall, rear lengthwise chamber sidewall  150   b  includes an inwardly projecting rib  176  that is essentially identical in configuration. 
     Referring to  FIG. 6 , each rib  176  defines an elongated slot  180  having a suitable configuration such as, for example, a semicircular cross-sectional shape, although any suitable configuration can be used in view of this description. An edge margin  182  of partition arrangement  160  includes a projecting, elongated tab  184  that is inset with respect to each of the outermost major surfaces of the partition arrangement. Tab  184  projects into slot  180  without contacting the interior surface of elongated slot  180 . Accordingly, rib  176  of the chamber cooperates with the vertical edge margins of the partition arrangement such that a circuitous, serpentine or non-line-of-sight path is defined between the opposing side margins of the partition arrangement and the respective chamber sidewalls which they confront. Suitable dimensions for a circuitous gap that is useful in the context of the present application include approximately 0.5 to 5 mm. Of course, a larger gap produces a greater conductance such that gap size can be tailored to the needs of a particular process. In this regard, it should be appreciated that a greater value of conductance is generally useful to further enhance pressure equalization at lower processing pressures. The significance of this highly advantageous configuration will be described an appropriate point below. 
     Referring to  FIG. 7 , the configuration of partition arrangement  160  with respect to chamber lid  106  will now be described.  FIG. 7  is an enlarged, partially cut away view taken at some representative point along the length of an upper edge margin  190  of the partition arrangement looking towards rear sidewall  150   b . Chamber lid  106  defines an elongated groove  192  having a length that is sized according to a length of an upper margin  190  of the partition arrangement. Upper margin  190  includes a projecting elongated tab  194  having an overall length which projects into groove  192  with chamber lid  106  in a closed position. As is the case with the partition and each of sidewall ribs  176 , described above, a circuitous path is formed through the cooperation of chamber lid  106  with tab  194 . Thus, such a circuitous path is formed at both side margins, as well as the upper margin of the partition arrangement. 
     Referring to  FIGS. 5 ,  8  and  9 , details will now be provided with regard to the way which the removable partition is selectively engageable and disengageable with chamber  104 .  FIG. 8  is a diagrammatic cross-sectional view, taken along a line  8 - 8 , as shown in  FIG. 3 , in a way which shows details with regard to selective attachment of the partition arrangement to the chamber. Opposing vertical edges of partition arrangement  160  are indicated by the reference numbers  196   a  and  196   b , in  FIG. 8 . Exhaust port  172  is illustrated by a double-headed arrow that extends between the surfaces which define its lateral extents. It is noted that the O-ring disposed between the chamber lid and chamber bowl is not shown for purposes of better illustrating those features that are of immediate interest.  FIG. 9  is a diagrammatic plan view of chamber  104  with the chamber lid removed, the partition arrangement removed and without wafers on wafer susceptors  120  and  122  so as to reveal all wafer pins  138 , only two of which are identified by reference numbers. Exhaust port  172  is also partially and one visible, as defined by chamber base  170 . Each lengthwise chamber sidewall  150   a  and  150   b  defines a pocket  200  for receiving a mounting tab  202  which extends laterally outwardly from partition plate  162  to be received in one of pockets  200 . As is best seen in  FIG. 5 , pocket  200  and mounting tab  202  cooperate to limit movement of partition arrangement  100  in a direction that is parallel to upper margin  190  of the partition arrangement and to limit movement of upper margin  190  in a direction that is generally normal to the plane of the partition arrangement. In this regard, it is noted that mounting tab  202  includes a width which is wider than the thickness of partition plate  162  so that each mounting tab is captured within each pocket  200 . It should also be appreciated that this arrangement further serves to establish the height of the partition arrangement within chamber  104 . A pair of fasteners ( FIG. 8 ), each of which is indicated by the reference number  210 , extends through respective holes that are defined by each one of mounting tabs to be received in each one of a pair of apertures, each of which is indicated by the reference number  212  ( FIG. 9 ), which are formed in lengthwise chamber sidewalls  150   a  and  150   b . Any suitable fastener may be used. In the present example, threaded stainless steel fasteners are used, having a head that is formed of, or covered with, same material as the chamber body. Mounting tabs  202  can be formed in any suitable way such as, for example, by using a separate sheet of material and, thereafter, attaching the mounting tab to the overall partition arrangement in a suitable way such as, for example, by welding. 
     Referring to  FIG. 8 , chamber base  170  supports a pin  220  which is centered with respect to a desired lengthwise or lateral position of the lowermost extents of partition  160 . This pin can may be formed from any suitable material such as, for example, stainless steel or an aluminum alloy and may be installed into the chamber base by any suitable technique such as, for example, by a pressed fit. An alignment cavity  222  is formed inwardly from the associated lower edge of partition plate  162  having a cavity width which is less than the thickness of the partition plate. As the partition arrangement is installed in chamber  104 , alignment cavity  222  is aligned to receive an upper end of pin  220  in a way which prevents lateral movement of the lowermost extents of partition arrangement  100 . Accordingly, the partition arrangement is supported at three points in a way which precisely establishes its position in every direction relative to the chamber. With regard to this position in a vertical sense, two lower edges of the partition arrangement, indicated by the reference numbers  224  and  226 , respectively, are in a confronting relationship with an interior surface of chamber base  170  when the partition arrangement is installed, as shown. These edges should be slightly out of contact with the chamber base. In the present example, a clearance of approximately 0.02 inch has been found to be acceptable. Rubbing contact between these lower edges and the chamber base is generally undesirable, depending on process constraints, since particle generation is likely to result. Lower edges  224  and  226  should, nonetheless, be arranged as closely as is reasonably practical to the chamber base, for reasons yet to be described. Partition plate  162 , at a lowermost end, also includes a pair of vertically disposed edges  230  and  232  having a width therebetween which is sized to be received in exhaust port  172  such that these edges are in a spaced apart relationship from the inner peripheral sidewall of exhaust port  172 . Edges  230  and  232  should, likewise, be arranged so as to be as close as practical while remaining out of contact with the inner peripheral sidewall of the exhaust port. 
     Attention is now directed to  FIGS. 4-7  for purposes of describing a feature which is formed as part of rear sidewall  150   b  of chamber  104 . Specifically, two essentially identical passage arrangements are formed in chamber sidewall  150   b  in a vertically spaced apart relationship with respect to one another. Accordingly, an upper one of these passage arrangements is indicated by the reference number  240   a  in  FIG. 6 . Passage arrangement  240   a  includes a main passage  242   a  that is formed, for example, by drilling from the outward facing major surface of sidewall  150   b . If so desired, a landing  244   a  can be formed surrounding main passage  242   a . First and second branch passages,  246   a  and  248   a  are formed so as to extend from each one of an opposing pair of inner surfaces of rib  176  inward to communicate with main passage  242   a . It is noted that an entrance opening of a branch passage  246   b  is seen in  FIG. 4  which forms part of the lower one of the passage arrangements. These passage configurations can be used for a number of different purposes and can serve in several capacities. For example, a manometer may be arranged to sense the pressure from main passage  242   a . As another example, one of these passage arrangements could be used for gas injection. In the present example, one of the passage arrangements is used for pressure sensing while the other is used for gas injection. Aside from the specific purpose for which each of these passage arrangements is used, it should be appreciated that each one of these passage arrangements defines a circuitous path from one side of partition  160  to the other side of partition  160 , thereby contributing to pressure equalization between processing stations  120  and  122 , while further acting in a highly advantageous manner that is yet to be brought to light at an appropriate point below. 
     Referring generally to the aforedescribed figures and having described the structure of chamber arrangement  102  in detail above, it is now appropriate to discuss a number of the advantages which it provides. In this regard, it is noted that the same process must be practiced at each processing station or one station may be idle. Of course, adjustments in gas mixtures, such as described above, can be made to further enhance process uniformity. It is recognized that a number of process related products are associated with plasma  134 . These process related products generally include non-reactive species such as, for example, Ar, CO 2 , O 2 , H 2  and reactive species such as, for example, charged ions, Ar + , H + , O − , O + , F − . It is further recognized that these two different types of species travel in different ways within chamber interior  108 . Specifically, non-reactive species are capable of traveling along a line-of-sight path and a non-line-of-sight, circuitous path while reactive species which react with chamber surfaces are generally capable of only line-of-sight travel. Moreover, it is considered that movement of non-reactive species from one processing station to the other processing station has little, if any, impact upon process results. On the other hand, it is considered that movement of reactive species from one processing station to the other processing station could have a detrimental influence upon process results. For example, if a charged particle, serving as a reactive species, is intended to impact a wafer at processing station  120 , but instead travels all the way so as to somehow impact a wafer at processing station  122 , such a charged particle may have an adverse affect on uniformity. Therefore, it is desired to minimize reactive species cross-contamination between the processing stations, while providing for free flow of non-reactive species between the processing stations. By providing for free flow of non-reactive species between processing stations, a high degree of pressure equalization is achieved. A high degree of pressure equalization is required to achieve process control with both optimal and mirrored process results between adjacent processing regions. This limited or selective communication of process related products between processing regions is required, at least in part, so to maintain equal pressure in adjacent processing regions. The communication path at three sides of the partition arrangement maximizes isolation of gas reactive gaseous process related products and allows exchange of non-reactive gaseous process related products within the processing chamber. Equal pressure in the adjacent processing regions is required to assure that the process results achieved in one process region mirror those results obtained in the adjacent processing region when a single pressure control system (not shown), as is used here, is used to monitor and control chamber pressure. Partition arrangement  100  also cooperates with the chamber to provide another benefit. In particular, light is unable to travel between processing stations such that instrumentation that is responsive to such light is not affected in an adverse way. For example, process end point control is often established based on optical measurements. Light traveling from one process station to the other could then influence the process end point at the other processing station. Partition arrangement  100  cooperates with chamber  106  in a way which is intended to effectuate these purposes. 
     Still another advantage is provided by chamber arrangement  102  of system  100  with respect to the maintenance requirements of the system. It should be appreciated that such systems require significant levels of maintenance in order to maintain better than acceptable process results. In particular, cleaning of the processing chamber must be performed at regular intervals, generally based on operational time. It is not uncommon for such a cleaning procedure to be performed on a weekly basis. In this regard, it should be appreciated that there is very little free space surrounding processing stations  120  and  122  within the chamber, as is typical in such a system for reasons which include minimizing chamber interior space—a common practice in vacuum systems. Partition arrangement  160  is highly advantageous with respect to the capability to remove the partition arrangement during regular cleaning and maintenance of chamber  104 , so as to significantly enhance access to the interior of the chamber. Moreover, the partition arrangement itself may readily be cleaned upon removal from the chamber. As an alternative, the partition arrangement may be disposed of and replaced by a new, clean partition arrangement. These features, in and by themselves, are considered to be highly advantageous. 
     Referring to  FIG. 8 , features which implement blocking of reactive species, while allowing a free flow of non-reactive species, include the circuitous gaps that are defined between partition arrangement edge  196   a  and rib  176  formed in chamber sidewall  150   b  and between partition arrangement edge  196   b  and rib  176  formed in chamber sidewall  150   a.    
     Referring to  FIG. 7  in conjunction with  FIG. 8 , another circuitous gap is defined between chamber lid  106  and upper margin  190  of the partition arrangement, as is described in detail above with regard to  FIG. 7 . It should be appreciated that the circuitous gaps that are defined along side margins  196   a  and  196   b , along with the circuitous gap at upper margin  190  of the partition arrangement all serve to block reactive product species in regions of chamber  104 , which contain relatively high concentrations of such reactive species proximate to processing stations  120  and  122 . Moreover, with portions of these circuitous gaps in very close proximity to sources  132  and the processing stations, the probability of at least some reactive species impinging on these gaps in a way which would otherwise allow line-of-sight transit therethrough is considerable. The situation, however, proximate to the lower extents of partition arrangement  100 , near chamber base  100 , is somewhat modified. In this lower region, reactive species generally arrive with a high degree of angular orientation with respect to the plane of partition arrangement  100 . For this reason, a sufficiently close clearance between each of edges  224 ,  226 ,  230 ,  232  and the confronted chamber surface, serves to block reactive species from transiting through these gaps. Another close tolerance gap is defined between a lowermost edge  249  of the partition arrangement and a baffle  250 , as will be described in detail below. For the moment, however, it is noted that this gap is likewise sufficiently narrow so as to block transport of reactive species. The limited width of each gap cooperates with the thickness of the partition arrangement, in a confronting relationship with a chamber interior surface, and the angular impingement of reactive species in this region, so as to block these reactive species in a highly advantageous way. It is noted that conductance for purposes of pressure equalization is not required through the subject gaps, since the circuitous gaps around the sides and the upper margin of the partition arrangement are configured to supply ample conductance. Thus, from a practical standpoint, it may be considered that all process related products are blocked. 
     Referring again to  FIG. 6 , it can be seen that passage arrangement  240   a , as described above, also defines a circuitous path between the processing stations which inhibits the flow of reactive species of therebetween. Concurrently, free flow of non-reactive species is permitted particularly when the passage arrangement is used for purposes such as instrumentation. 
     Turning now to  FIGS. 8-10 , another highly advantageous feature that is used in system  100  will now be described.  FIG. 10  is a diagrammatic, perspective view of system  100  having a front portion of chamber  104  cut away in order to better illustrate those features which are currently of interest. In particular, aforementioned baffle  250  is visible in pump spool  144 , forming part of the exhaust arrangement, in the view of  FIG. 10 . Baffle  250  is also seen in the elevational view of  FIG. 8  and in the plan view of  FIG. 9 , comprising a generally planar plate-like member and may be formed, for example, from the same material that spool  144  is formed from including, but not limited to aluminum alloys. Baffle  250  may be installed in any suitable manner in pump spool  144  such as, for example, by welding. The baffle is positioned within the circular cross-section of the pump spool cavity, for example, in a way which defines a pair of opposing semicircular passages. An upper edge  252  ( FIG. 10 ) of baffle  250  is vertically positioned so that the desired spaced apart relationship is achieved with lowermost edge  248  of partition arrangement  160 , as is illustrated in  FIG. 8 . In this way, aside from the narrow gap between the lowermost partition edge and the upper edge of the baffle, baffle  250  essentially represents a continuation of partition arrangement  160  external to chamber  104 , extending into exhaust arrangement  140 . In the view of  FIG. 9 , the plane of baffle  250  is generally normal to and bisects a line drawn between the center positions of processing stations  120  and  122 . In the present example, baffle  250  has an overall length that is greater than the length of pump spool  144  such that a portion  254  of baffle  250  extends into the exhaust system below pump spool  144 . Thus, portion  254  of the pump spool baffle may extend into a component such as a pendulum valve (not shown) or other suitable valve. It is important, however, that portion  254  is sized lengthwise in a way which does not interfere with any component therebelow. 
     Baffle  250  has been found to enhance process uniformity for reasons which are thought to include minimization of communication of gaseous process exhaust products by reduction of back diffusion of gaseous process exhaust products from one process region to the adjacent process region in the exhaust system preceding the valve and vacuum pump (not shown) attached to the bottom of pump spool  144 . In this regard, it should be noted that chamber  104  and partition arrangement  160 , in and by themselves, cooperate, independent of baffle  250 , to provide pressure equalization which serves to minimize back diffusion related contamination. Highly effective results have been demonstrated using baffle  250  in combination with the use of partition arrangement  100 . 
     Generally considering system  100 , the replaceability of partition arrangement  160  is advantageous for another reason. Initially, it should be appreciated that partition arrangement  160  establishes an exchange characteristic of the process related products between processing stations  120  and  122 , when positioned therebetween. By replacing this partition arrangement with a modified partition arrangement, it should be appreciated that a modified exchange characteristic of the process related products can be established between the processing stations. The exchange characteristic may relate to mobility of the process related products. Further, the system may be operated without a partition arrangement. 
     Attention is now directed to  FIG. 11  which illustrates system  100  in essentially the same view as that of aforedescribed  FIG. 10 , with the exception that partition arrangement  160  has been replaced by a modified partition arrangement  160 ′. Further, pump spool  144  has been replaced with a modified pump spool  144 ′, which does not include a welded-in baffle. In this regard, modified partition arrangement  160 ′ includes a chamber partition portion  260  and a baffle portion  262 . Modified pump spool  144 ′ includes a rail arrangement  264  having a pair of opposing rails, only one of which is visible in the view of this figure, that slidingly receives baffle portion  262 , as the overall modified partition arrangement is inserted into the system. These rails, having a “C” or “U” shaped cross-sectional configuration, may cooperate with baffle portion  262  so as to define circuitous gaps between the confronting edges of the baffle portion and each rail. Modified partition arrangement  160 ′ may be formed in any suitable manner such as, for example, having partition portion  260  integrally formed with baffle portion  262 . Suitable materials for use in forming the modified partition arrangement include, but are not limited to aluminum alloys. Alternatively, separate pieces can be used for each of the baffle portion and the partition portion, attached to one another in a suitable manner such as, for example, by welding. It should be appreciated that the modified partition arrangement cooperates with chamber  104  in a way which shares all of the advantages described above. Still further advantages may be provided with regard to cleaning or replacing the baffle portion of the modified partition arrangement during maintenance as well as providing for ease of cleaning the interior of modified pump spool  144 ′. Although, it should be noted that contaminant build up in the pump spool is not generally considered to be as serious as contaminant build up within chamber  104 , at least due to its more remote location from the processing stations. 
     Referring now to  FIG. 12 , an enlarged cross-sectional cutaway view is provided, taken through the thickness t of the partition arrangement, showing an alternative configuration of bottom edge  249  of partition arrangement  100 . In this alternative configuration, a notch  280  is formed inward from lowermost edge  249  having a width w, which is less than the thickness of the partition arrangement, but greater than a thickness x of baffle  250 . An upper edge  282  of baffle  250  is vertically positioned so as to either be coplanar with the remaining portions of bottom surface  249  of the partition arrangement or so that the baffle extends into notch  280  in a noncontacting manner. In this way, a circuitous path  284  can be defined between the partition arrangement and the baffle so as to function in the manner described above with respect to process related products. 
     Referring collectively to  FIGS. 13   a - d , a number of alternative configurations are diagrammatically illustrated for use in forming a circuitous gap between the partition arrangement and baffle. Conductance, for purposes of pressure equalization is not required through the partition/baffle interface, since the circuitous gaps around the sides and the upper margin of the partition arrangement are configured to supply ample conductance in view of the particular process that is being practiced. Further, minimizing the partition/baffle interface gap further reduces opportunities for diffusion-related exhaust backflow contamination. It is noted that the configurations of  FIGS. 13   a - d  are conceptually applicable to forming a circuitous gap (see, for example,  FIGS. 6 and 7 ) between chamber  104  and partition arrangement  160 , in conjunction with the foregoing descriptions. 
       FIG. 13   a  illustrates partition arrangement  160  and baffle  250  (each of which is shown partially cutaway) cooperatively configured in a way which defines a semicircular gap  290 . It is of interest to note that the thickness of the baffle can be equal to the thickness of the partition arrangement. It should also be appreciated that these configurations can be inverted with the understanding that particle collection could occur in the gap. 
       FIG. 13   b  illustrates partition arrangement  160  and baffle  250 , in the manner of  FIG. 13   a , wherein baffle  250  is thinner than the partition arrangement and a rectangular notch  292  is defined from the lowermost edge of partition arrangement  160 . This configuration resembles the configuration of  FIG. 12  with the difference that an upper end portion  294  of the baffle extends into notch  292 . 
       FIG. 13   c  illustrates partition arrangement  160  and baffle  250  (each of which is shown partially cutaway) having an identical thickness and cooperating to define therebetween a chevron shaped gap  296 . 
       FIG. 13   d  illustrates partition arrangement  160  (shown partially cutaway) having a greater thickness than baffle  250  (shown partially cutaway) such that the partition arrangement defines an inverted V-shaped cavity  298 . An upper end  300  of the baffle extends into cavity  298  and is configured to cooperate with a center portion of the inverted V shape so as to define a chevron shaped gap  302 . 
     As will now be appreciated, a highly advantageous system is provided which accommodates high throughput without a need to resort to the use of a single process chamber environment by selectively controlling movement of individual components of process related products between process stations in a common/shared processing chamber and associated environment. 
     Although each of the aforedescribed physical embodiments have been illustrated with various components having particular respective orientations, it should be understood that the present invention may take on a variety of specific configurations with the various components being located in a wide variety of positions and mutual orientations. Furthermore, the methods described herein may be modified in an unlimited number of ways, for example, by reordering, modifying and recombining the various steps. Accordingly, it should be apparent that the arrangements and associated methods disclosed herein may be provided in a variety of different configurations and modified in an unlimited number of different ways, and that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Therefore, the present examples and methods are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein.