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Patent Application Titled "Method and Apparatus for a Cleanspace Fabricator" Published Online

February 6, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventor Flitsch, Frederick A. (New Windsor, NY), filed on September 11, 2013, was made available online on January 23, 2014.

No assignee for this patent application has been made.

Reporters obtained the following quote from the background information supplied by the inventors: "A known approach, to cleanspace-assisted fabrication, is to assemble the manufacturing facility as a 'cleanroom.' In such cleanrooms, processing tools are arranged to provide aisle space for human operators or automation equipment. An example text on cleanroom design (referred to herein as 'the Whyte text') is as follows: 'Cleanroom Design, Second Edition,' edited by W. Whyte, published by John Wiley & Sons, 1999, ISBN 0-471-94204-9. The Whyte text is incorporated herein by reference in its entirety.

"Cleanroom design has evolved over time to include the following techniques. Having processing stations located inside clean hoods. Having vertical unidirectional air flow through a raised floor, with separate cores for the tools and aisles. Having specialized mini-environments that surround only the processing tool for added space cleanliness. The 'ballroom' approach, where tools, operators and automation all reside in the same cleanroom.

"Evolutionary improvements have enabled higher yields and the production of devices with smaller geometries. However, known cleanroom design has disadvantages and limitations.

"For example, as the size of tools has increased and the dimensions of cleanrooms have increased, the volume of cleanspace that is controlled has concomitantly increased. As a result, the cost of building the cleanspace, and the cost of maintaining the cleanliness of such cleanspace, has increased.

"Tool installation in a cleanroom can be difficult. The initial 'fit up' of a 'fab' with tools, when the floor space is relatively empty, can be straight forward. However, as tools are put in place, and a fab begins to process substrates, it can become increasingly difficult, and disruptive of job flow, to either place new tools or remove old ones. It would be desirable to reduce the installation difficulties, attendant to dense tool placement, since denser tool placement otherwise affords substantial economic advantages for cleanroom construction and maintenance.

"Another area of evolutionary improvement has come with improvements in robotics. Substrate processing has changed from a manually intensive process where human operators handle substrates or batches of substrates. In current cleanroom designs, the tools can include robotics for substrate handling, with human operators only needing to perform the following functions: loading collections of substrates onto tools, unloading collections of substrates from tools and moving collections of substrates from one tool to another. In some cases, automation performs all handling and logistics operations. Despite the evolutionary advances, cleanroom robotics remain extremely complex. The robotics can therefore be error prone and costly.

"It would be desirable to have manufacturing facilities, for cleanspace-assisted fabrication, that use less cleanspace, permit dense tool placement while maintaining ease of installation and permit the use of simpler robotics."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventor's summary information for this patent application: "Please refer to the Glossary of Selected Terms, included at the end of the Detailed Description, for the definition of certain selected terms used in the below Summary. Section numbers in the below Summary correspond to section numbers in the Detailed Description.

"1. Summary of the Ballroom Approach

"Details of a large modern ballroom cleanroom are presented to illustrate some of the functional requirements of a fabricator that are addressed by the present invention.

"A distinctive feature, of the ballroom approach to cleanroom design, is that the tools, automation, robotics and personnel can be found occupying the same cleanspace.

"A ballroom cleanroom can have an area on the order of 90,000 square feet. These dimensions imply that the cost of construction of the fab, and the cost of cleaning the cleanroom air, are quite high. In general, these costs are related to both the volume of air that needs to be cleaned and to the vertical height, of the cleanspace, that the unidirectional air must traverse.

"The relatively large planar aspect of the cleanroom space makes for substantial dimensions with respect to logistics.

"Since most tools cannot reside on the perimeter of the ballroom plane, once a tool is located in its position, at some interior location of the two dimensional plane, it is difficult to move or remove the tool without disturbing other tooling and logistics in the cleanspace.

"2. Summary of a Round Tubular Annular Fab

"2.1. Summary of Overall Construction

"An example embodiment of a round tubular annular fab, constructed in accordance to principles of the present invention, is presented. A basic geometric shape, according to which the round tubular annular fab can be constructed, can be referred to as a round annular tube. It is comprised of an outer tube and an inner tube, where the inner tube defines the annular region. The primary cleanspace is located in-between the inner and outer tubes.

"An example embodiment of a round tubular annular fab can be encircled with shelves (or levels) upon which tools are located. The number of levels is not limited to a particular value.

"The example cleanspace fabricator presented can be used to make standard semiconductor substrates.

"In an example embodiment of a round tubular annular fab, the outer primary cleanspace wall is the air source wall and the inner primary cleanspace wall is the air receiving wall.

"Details are presented on how the air source, and air receiving, walls of a primary cleanspace can be constructed.

"The air source wall can be constructed of panels, an example embodiment of which is presented.

"An example embodiment of a round tubular annular fab locates tool bodies on the exterior of the outer primary cleanspace wall and each tool's port on the inside of the primary cleanspace.

"Air flow, for a fabricator constructed in accordance with the principles of the invention, needs to achieve enough velocity such that a unidirectional flow regime, in accordance with standard requirements for cleanroom-assisted fabrication, is established.

"A geometric property of a round tubular annular fab, when its tools are placed at peripheral locations of the primary cleanspace, is that each tool can be provided with a property referred to as 'unobstructed removability.' In particular, each tool has an essentially straight path by which it can be installed or removed, without encountering either significant structural components of the fab or the bodies of other tools. To the extent a tool body is located exterior to the outer wall of the primary cleanspace, in which its port operates, unobstructed removability can be enhanced.

"Unobstructed removability can offer at the least the following advantage when removing a tool from the manufacturing line: the fab operations in the region of the tool need only be stopped, if at all, during the relatively brief time period when the tool is removed and a replacement tool is installed. The removed tool can then be serviced at a location outside the fab, with the replacement tool taking over the production requirements.

"In addition to enhancing unobstructed removability, to the extent the body of each tool is located exterior to the primary cleanspace, the volume of the primary cleanspace can be reduced. The primary cleanspace can be reduced to a minimum size, with respect to serving the space needs of the tools, if only the tool ports are located in the primary cleanspace. In this case, the primary cleanspace only needs to provide for material transport. Space for material transport can be further reduced if only robotics is used. Minimizing the space for material transport can minimize the technical and economic requirements for establishing unidirectional flow and adequate cleanliness.

"A primary cleanspace, designed in accordance with the general layout of a round annular tube shape, permits the establishment of unidirectional air flow even when the density of tool placement, per unit area of primary cleanspace wall, is extremely high. Denser tool placement, when it does not impair clean air flow, provides economic advantages. For example, denser tool placement can permit the overall size of a cleanspace-assisted manufacturing facility to be reduced.

"2.2 Summary of Robotics and Logistics

"Compared with the robotics needed for conventional ballroom cleanrooms, fabs designed in accordance with the present invention can utilize highly simplified robotics.

"A fab designed in accordance with the round annular tube shape, for example, has a primary cleanspace geometry that approximates a curved two-dimensional space. A robot to support such a primary cleanspace only needs two degrees of gross movement capability.

"An example of how robots can be located, in the primary cleanspace of a round tubular annular fab, is presented.

"Redundant robotics equipment can be desirable so that, in the case of only some robots malfunctioning or needing servicing, transportation of jobs can continue.

"The logistics of transport between tools can also be simplified, compared to known approaches to cleanroom design, since job transport can occur with a 'fluid' motion that combines varying the two gross degrees of freedom, angle and height, simultaneously.

"2.3 Summary of Including a Secondary Cleanspace

"In the round tubular annular fab designs discussed thus far, while tool ports are located in a primary cleanspace, tool bodies are placed in an unspecified environment that can be clean or not.

"Techniques are presented by which the tool bodies can be placed in a secondary cleanspace. An exterior boundary wall can be added. As with the primary cleanspace, unidirectional flow can be achieved by constructing the secondary cleanspace with an air source wall and an air receiving wall.

"The cleanliness requirements of the secondary cleanspace can be different than the primary cleanspace. Typically, the secondary cleanspace can have less stringent cleanliness requirements.

"There can be a sealing surface on the body of each tool where it intersects the exterior wall forming the secondary cleanspace. The intersection can be constructed to permit relatively simple and fast removal of a tool (and thereby preserve the property of unobstructed removability).

"(Section 2.4 'Utilities Support' is not summarized.)

"2.5. Summary of Construction Advantages

"An advantage realized with the multilevel aspect of the round tubular fab is during its construction or 'build.' Lessening the time of a fab's build can provide significant economic advantages.

"Each level of a fab can be constructed of two types of sub-units. Multiple copies, of each type of sub-unit, can be prefabricated.

"Utilization of two types of sub-units is just an example of a prefabrication strategy. Any appropriate unit of a fab can be chosen for prefabrication.

"In addition to assisting in the initial 'build' of a fab, prefabricated units can be used in the maintenance or repair of a fab.

"3. Summary of Alternate Embodiments

"3.1 Summary of Overview

"When constructing a fab in accordance with teachings of the present invention, there are other shapes, besides the round annular tubular shape, that can be used.

"An example, of such other shapes, is the rectangular annular tubular shape. A fab constructed in accordance with this shape, referred to as a rectangular tubular annular fab, is presented.

"In general, the round annular tubular shape and the rectangular annular tubular shape can be viewed as specific instances of the technique of curving or folding the conventional planar ballroom cleanroom to produce a primary cleanspace. This curving or folding technique can be applied to produce numerous alternative shapes to the types focused on herein. For purposes of example, and without limitation, these shapes can include non-annular tubes, spheres, hemispheres and pyramids.

"One skilled in the area of conventional fabricator design can readily appreciate how the techniques presented herein can be applied to other cleanspace geometries. Based upon the discussion of a round tubular annular fab, it can readily be appreciated how the property of unobstructed removability can be preserved with other primary geometries. Also, based upon the discussion of a round tubular annular fab, it can readily be appreciated how the technique of prefabrication can be applied to other geometries.

"Examples, of how the techniques presented herein can be applied to other cleanspace geometries, are presented. These example geometries are as follows: a round tubular non-annular fab, a rectangular tubular annular fab and a section of a tubular annular fab.

"3.2 Summary of Round Tubular Non-Annular Fab

"The round tubular non-annular fab is related to the round tubular annular fab. With its tools arranged at locations peripheral to the primary cleanspace, the property of unobstructed removability can be preserved. With its primary cleanspace being divided into levels, like those presented for round tubular annular fab, similar opportunities are preserved for using prefabricated units in its construction, repair or maintenance.

"Technical difficulties of a round tubular non-annular fab, compared with the annular version, are discussed.

"3.3 Summary of Rectangular Tubular Annular Fab

"The rectangular tubular annular fab is related to the round tubular annular fab. With its tools arranged at locations peripheral to the primary cleanspace, the property of unobstructed removability can be preserved. With its primary cleanspace being divided into levels, like those presented for round tubular annular fab, similar opportunities are preserved for using prefabricated units in its construction, repair or maintenance.

"Differences, between a rectangular tubular annular fab and round tubular annular fab, are also presented.

"Some differences include the following. In a rectangular tubular annular fab the support shelves are straight and the cleanspace has corners that can cause turbulence.

"The robotics can be similar to the robotics of the round tubular annular fab, but some differences are discussed.

"In an analogous fashion to the round tubular annular fab, an outer wall can be added to a rectangular tubular annual fab to form a secondary cleanspace for the tool bodies.

"The establishment of unidirectional air flows, in the primary and/or secondary cleanspaces, is presented.

"3.4 Summary of Section of a Tubular Annular Fab

"A variation, on the tubular annular fab, either round or rectangular, can be created by 'cutting' (or sectioning) off a portion of the fab along a cut line or lines. The selection of an appropriate cut line can be guided by various considerations, including its effect on the complexity of transport automation.

"Example sectionalizations, for greater access to annular regions, are presented.

"An example sectionalization, that can be served by relatively simple transport automation, results from application of the following cut line to a rectangular tubular annular fab: a cut line that lies on one straight side of the interior annular region. The fab thus formed is, essentially, a one-quarter section of a rectangular tubular annular fab (referred to herein as a 'one-quarter rectangular tubular annular fab'). An example of this type of fab is shown.

"In general, however, while a section of a tubular annular fab may no longer have a curved primary cleanspace, a novel fabricator can still be realized if it has at least one of the following two configurations.

"A first configuration is that tools of the fabricator be stacked, one on top of the other, according to a vertical dimension (i.e., along a dimension substantially parallel to gravity). While not necessary, an important additional improvement, for the first configuration, is that each tool body of the fabricator be placed at a peripheral location of the primary cleanspace.

"The second configuration is a combination of the fabricator's primary cleanspace being nonsegmented and having the tool bodies at peripheral locations of the primary cleanspace where at least a portion of the tool bodies are outside the primary cleanspace.

"Other than the fact that a section has been taken of a tubular annular fab, a section of a tubular annular fab can be constructed in, essentially, the same way that a non-sectioned tubular annular fab is constructed.

"Sectional tubular annular fabs share advantages in common with non-sectional tubular annular fabs. Dense tool placement is enabled. Primary cleanroom space can be reduced to the minimum required for transport automation. In the case of sectional rectangular tubular annular fabs, the same linear placement of tools along the outer wall of the primary cleanspace, as in a rectangular tubular annular fab, can be utilized.

"The location of the tool bodies, along the outer wall of the primary cleanspace, tends to preserve the property of unobstructed removability. The fabricator being divided into levels, like those of round tubular annular fab, provides similar opportunities for using prefabricated units in its construction, repair or maintenance.

"The planar aspect of the one-quarter rectangular tubular annular fab allows for alternate types of robotic design.

"The construction of the air source wall for the primary cleanspace, from panels that include filters, can be accomplished in an equivalent fashion to that discussed for the round tubular annular fab.

"An exterior boundary wall can be added in order to establish a secondary cleanspace for the tool bodies. Example unidirectional air flows, for the primary and/or secondary cleanspaces, are presented.

"Tool bodies can intersect the exterior wall of the secondary cleanspace in the same way that tool bodies intersect the exterior wall for the secondary cleanspace of a round tubular annular fab. In addition to providing a seal, the intersection can be constructed to permit relatively simple and fast removal of a tool (and thereby preserve the property of unobstructed removability).

"4. Summary of Scaling Issues

"An inventive cleanspace-assisted fabricator, as described above, can be scaled larger or smaller depending upon the particular needs of the fabricator's users.

"As an alternative, or as an addition, to scaling a fab, multiple copies of a fab can be coupled together to produce a facility that, overall, provides greater throughput.

"The cleanspace fabricator designs presented herein can be scaled down to construct fabrication facilities (referred to herein as a 'minifab') of a size that would typically be considered impractical for conventional fab designs. For example, a minifab can be constructed that uses a minimal number of tools for implementation of a process (e.g., one tool for each tool type).

"The costs associated with a minifab can be reduced, for example, by the unobstructed removability of its tools. A tool needing repair (or other servicing) can be easily replaced by relatively unskilled personnel. The tool to be serviced can then be 'sent out' for such servicing. For example, the tool needing service can be sent out for repair by a party other than the party that owns or operates the minifab. Centralized pooling of the repair function can permit the cost, per repair, to be reduced.

"In contrast, with a ballroom type fab, the cost of removing a tool from the fab can be higher than the savings in repair cost gained by transporting the malfunctioning tool to a centralized pooling of the repair function.

"5. Summary of Completing a Fabricator

"The novel cleanspace fabricators presented can be accomplished with relatively minor adaptations of known components and materials.

"The process, by which an automation system determines the next tool to which a job should be sent, can be referred to as a 'logistics hierarchy.' Only the lowest levels, of such logistics hierarchies, are specific to the physical layout of the fab it controls. The lowest levels comprise the means by which a job, at a physical starting tool location, is transported to a correct next-tool physical location to continue a process.

"Thus, to adapt a logistics hierarchy to a particular fab's physical realization, one need only solve the following control issue: the transfer of a job from one arbitrary physical tool location of the fab to any other arbitrary physical tool location of the fab.

"An example logistics hierarchy is presented.

BRIEF DESCRIPTION OF THE DRAWINGS

"The accompanying drawings, that are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention:

"FIG. 1A depicts an elevation view of a cleanroom, constructed according to the known 'ballroom' approach.

"FIG. 1B depicts a cross section of the same cleanroom of FIG. 1A.

"FIG. 2 depicts an elevation detail of the cleanroom of FIG. 1A.

"FIG. 3 depicts examples shapes formed when a cleanroom is closed upon itself.

"FIG. 4A depicts a round tubular annular fab, elevation view (an XYZ axis is indicated by numeral 450).

"FIG. 4B depicts a round tubular non-annular fab (i.e., a round tubular fab without an annular region), elevation view (an XYZ axis is indicated by numeral 450).

"FIG. 5 depicts a round tubular annular fab, top view.

"FIG. 6A depicts a round tubular annular fab, top view, with unidirectional air flow shown.

"FIG. 6B depicts a round tubular non-annular fab, top view with unidirectional air flow shown.

"FIG. 6C depicts a side view of a round tubular non-annular fab with multiple level cleanspace air flow shown.

"FIG. 7 depicts a round tubular annular fab, detailed elevation view, with robotics shown.

"FIG. 8A depicts a view of wall construction with a HEPA filter panels.

"FIG. 8B shows a detailed (elevation) view of the construction of a wall panel that includes HEPA filters.

"FIG. 8C shows a detailed (elevation) view of a HEPA filter wall panel with a tool port attached.

"FIG. 9A depicts a round tubular annular fab, elevation view, with a secondary cleanspace.

"FIG. 9B depicts a round tubular annular fab, top view, with secondary cleanspace and unidirectional air flows shown.

"FIG. 10 shows, schematically, primary cleanspace air-flow-source wall with ports (interior view from opposite wall of primary cleanspace).

"FIG. 11A shows a trajectory of a job transfer from one tool to another tool in a ballroom cleanspace.

"FIG. 11B shows a higher magnification view of two regions of FIG. 11A.

"FIG. 11C shows a trajectory of a job transfer from one tool to another tool in a round tubular annular fab.

"FIG. 12 depicts a construction technique for a round tubular annular fab.

"FIG. 13 depicts a rectangular tubular annular fab, elevation view (an XYZ axis is indicated by numeral 1350).

"FIG. 14 depicts a rectangular tubular annular fab, detailed elevation view, with primary and secondary cleanspaces.

"FIG. 15A depicts a rectangular tubular annular fab, elevation view, with primary cleanspace air flow shown.

"FIG. 15B depicts a rectangular tubular annular fab, top view, with primary and secondary cleanspace unidirectional air flows shown.

"FIG. 16 depicts a one-quarter section of a rectangular tubular annular fab, elevation view (an XYZ axis is indicated by numeral 1650).

"FIG. 17 depicts a one-quarter section of a rectangular tubular annular fab, elevation view, with robotics shown.

"FIG. 18 depicts a one-quarter section of a rectangular tubular annular fab, top view, with robotics and an air flow shown.

"FIG. 19 depicts a one-quarter section of a rectangular tubular annular fab, elevation view, with primary and secondary cleanspaces shown.

"FIG. 20 depicts a one-quarter section of a rectangular tubular annular fab, top view, with primary and secondary cleanspace air flows shown.

"FIG. 21 depicts a plurality of one-quarter section rectangular tubular annular fabs, elevation view, coupled together for inter-section job flow.

"FIG. 22 depicts an example logistics hierarchy."

For more information, see this patent application: Flitsch, Frederick A. Method and Apparatus for a Cleanspace Fabricator. Filed September 11, 2013 and posted January 23, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=6591&p=132&f=G&l=50&d=PG01&S1=20140116.PD.&OS=PD/20140116&RS=PD/20140116

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