Transfer Chamber for Air-Sensitive Sample Processing
A transfer chamber is disclosed having a first plate with a first surface configured to receive a sample and a second surface containing a groove. The second surface of the first plate surrounds the first surface of the first plate. A second plate has a first surface and a second surface containing a groove. A sealing component is disposed in the groove of the first plate or the second plate. A pivotable link couples the first plate and the second plate. The pivotable link is configured to hold the first plate, the second plate, and the sealing component together to substantially create an air-tight seal between the first surface of the first plate and the second surface of the second plate. The pivotable link is configured to open the seal in response to a pressure differential across the transfer chamber.
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This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 61/709,523 filed on Oct. 4, 2012, the disclosure of which is incorporated herein in its entirety.
STATEMENT OF GOVERNMENT LICENSE RIGHTSThe present invention was made with government support under contract number DE-AC02-98CH10886 awarded by the U.S. Department of Energy, Office of. Basic Energy Sciences. The United States government may have certain rights in this invention.
FIELD OF THE INVENTIONThe present disclosure relates to degradation avoidance mechanisms and methods for avoiding exposure of materials, including semiconductors and metals, to ambient air.
BACKGROUND OF THE RELATED ARTMany materials used in electronic applications, including semiconductors and metals used in advanced solar cells and thin film transistors, may degrade upon exposure to ambient air. Exposure can adversely affect the optical and electronic characteristics of devices that subsequently incorporate these materials. As a result, device performance and device lifetime may be negatively impacted by these types of exposures.
An exemplary source of degradation may be air exposure during material processing prior to encapsulation of the device. This may be due to air seepages into storage containers or storing chambers while the material transitions between localities having differing pressures. One such example may be the transitioning of semiconductor substrates from one area of high pressure to another area of lower pressure following atomic layering, doping, or etching processes. Different pressure transitions during other metal device processing may also be encountered and thereby involve similar air exposure and degradation problems.
Examples of degradation mechanisms include effects due to the oxygen content and the water content of air. Oxygen degrades organic semiconductors by oxidizing conjugated molecules and polymers making up the semiconductors. Additionally, unintentional doping of semiconductors by molecular oxygen can lead to changes in carrier concentration. Reactions with oxygen and water at the interface between two materials can lead to undesirable effects. Water, as well as oxygen, is known to react with dielectric interfaces causing a shift in the threshold voltage of organic as well as other thin film transistors.
Typically, a network of inter-connected glove boxes forming a controlled-environment processing line is required to carry out all stages of device fabrication in an inert atmosphere or vacuum, for example, in environments without exposure to ambient oxygen or water. The network preferably would contain equipment for preparation of solutions, for example, a balance, a magnetic stirrer, a hotplate, solution processing equipment such as a spin coater or blade coater, and vacuum deposition equipment such a thermal evaporator, an electron-beam evaporator, or an atomic layer deposition system.
Inter-connected glove boxes are not available in many laboratory and R&D environments. This is due in part to the fact that controlled-environment processing lines are more expensive to implement compared to similar processing lines utilizing sample transfer in ambient air. A facility that wishes to work with air-sensitive materials, but is not specially built for controlled-environment processing, may not be able to justify acquisition of new processing lines. Often times, however, similar solution processing and vacuum deposition equipment that is compatible with air-stable materials already exists within a laboratory.
A further complication exists in the ability to seal a storage container under inert atmosphere and subsequently open it in a vacuum deposition process chamber. It would be advantageous to avoid the use of mechanical manipulation feed-through or electrical feed-through to effect such transitions during device processing.
SUMMARYAn exemplary transfer chamber according to various embodiments of the present invention enables the use of air-sensitive samples with a wide variety of vacuum deposition tools. The transfer chamber may circumvent one or more of the limitations described by providing a means of transferring samples from an inert atmosphere, such as one provided by a glove box, to a vacuum deposition process chamber without exposure of the sample to ambient air.
According to another aspect of various disclosed embodiments, an exemplary transfer chamber can easily be assembled in a glove box and sealed in the antechamber of a typical glove box system. All that is required to seal the transfer chamber is a means to reduce the pressure of the antechamber below ambient pressure while the transfer chamber sits inside.
According to various aspects of disclosed embodiments, opening, or un-sealing, of an exemplary transfer chamber may be driven by pressure differentials between the low pressure of a deposition process chamber (which may be for example, less than 1 milliTorr) and a higher pressure in the sealed transfer chamber (which may be approximately 10 milliTorr). An exemplary transfer chamber may experience an ambient pressure during sample loading while present in the vacuum deposition process and subsequently experience lower pressures during further processing.
An exemplary transfer chamber during the crossover from ambient pressure (above that of the transfer chamber), to low pressure (below that of the transfer chamber), may take advantage of suitable pressure differential regimes to allow access to its contents during multi-pressured processing.
According to the illustrative embodiment disclosed in cross-sectional view in
In an exemplary embodiment, an O-ring 80 may be coupled to a surface 161 of back plate wall 160. O-ring 80 may be attached to door 140 by means of adhesive, friction fitting or any other coupling mechanisms known to those skilled in the art. Preferably, gasket 80 is an O-ring that may be coupled within a recessed portion of surface 141 that engages a complementary surface 161 of wall 160 of back plate 130 to create an air-tight seal about the closed space formed by the back plate 130 and the front plate assembly 140a and/or 140b.
Exemplary back plates 130, front plate assemblies 140a and 140b, and chamber wall(s) 160 may be constructed from stainless steel as well as other metals or composites. Suitable hinges for the purposes of the embodiments related to
While certain of the exemplary transfer chambers described may optionally include a port with a valve connecting to the inside of the transfer chamber to evacuate the transfer chamber, another exemplary transfer chamber embodiments do not require such a port with a valve. According to one exemplary embodiment, a vacuum chamber may be evacuated through the port and valve in order to seal the chamber. However, in a preferred embodiment, an exemplary transfer chamber 100 may be sealed without use of a port and valve by placing it within a container accommodating the transfer chamber's shape and size and evacuating the transfer chamber through the gasket 80, thereby creating a seal.
Depending on the process involved, a mounting bracket 120 may be used for mounting transfer chamber 100 in operation. Mounting bracket 120 may engage back plate 130 by means of bolts 20 engaging interior surfaces of back plate 130. Alternatively, mounting bracket 120 may be coupled to back plate 130 by sliding engagements, hooks or other forms of non-permanent mechanical coupling known to those skilled in the art.
An exemplary transfer chamber 100 may be used with any means for processing a sample held therein, including, vacuum deposition systems, etching tools, x-ray characterization, microscopy applications, and lithographic systems. For example, in a physical vapor deposition system, samples held by an exemplary transfer chamber are placed face down above the deposition source for processing. In one embodiment, after placement of an exemplary sealed transfer chamber 100 in a vacuum process chamber, a pressure differential created during evacuation of the process chamber causes displacement of elbow 140b which hinges door 140a to back plate 130 and/or walls 160. Door 140a may open due to a pressure differential outside of transfer device 100. For example, when the pressure internal to the chamber exceeds that of the external environment, door 140a will swing downward as a result of its own weight. By virtue of this exemplary process using an exemplary transfer chamber 100, a sample configured to be placed in one or more grooves 135, may be exposed to an incident flux from a deposition source. In an exemplary transfer chamber, the sample may be held in place by a mechanical clip or adhesive, such as, for example, vacuum grease or vacuum-compatible double-sided tape.
According to the illustrative embodiment disclosed in
Those skilled in the art may recognize that geometric and size constraints may affect the arrangement and size of parts of an exemplary transfer chamber according to any of the embodiments disclosed. In one aspect, geometric limitations on an exemplary transfer chamber may limit its physical dimensions, making hinged-door approaches difficult.
According to the exemplary embodiment disclosed in
While the shapes and arrangement of the top plate 306, bottom plate 305 and legs 316 appear as cylindrical shapes, it may be appreciated that these components of transfer chamber 300 may be shaped and sized accordingly to fit within a target vacuum chamber or accommodate a certain size and amount of sample.
According to the exemplary embodiment of
In a preferred embodiment, a vacuum chamber 500 is 5 mm high and the transfer chamber 300 would be less than 5 mm high. Bottom plate 305 and top plate 306 are each approximately 1 mm thick and separated by a gasket 70, such as a vacuum O-ring. For example, where top plate 306 is circular, its larger diameter on seating surface 310 may accommodate a plurality of legs 316 configured to suspend a surface 303 of bottom plate 305 approximately 1 mm into the air. Alternatively, top surface 302 of top plate 306 may have dimensions the same as or different from seating surface 310. The central portion of top plate 306 may accommodate vacuum sealing coupling from gasket 70 affixed to bottom plate 305 holding sample 1 on its holding surface 309. When the pressure external to the transfer chamber exceeds that inside the chamber, gasket 70, which may be an O-ring as previously described, may sealingly engage seating surface 310 so that the holding surface 309 of bottom plate 305 faces the seating surface 310 of top plate 306.
After placement of the exemplary sealed transfer chamber 300 in a vacuum process chamber 500, pressure differentials created during evacuation of the process chamber may cause bottom plate 305 to be displaced thereby revealing sample 1. When dislodged, bottom plate 305 may be configured to reduce shocks to a sample, such as a substrate, bound to holding surface 309 by either a miniature spring or elastic components coupled to surface 303. Alternatively, an exemplary transfer chamber 300 may have a sample held on seating surface 310 to reduce occasion for shocks from falling bottom plate 305 upon pressure reduction and de-coupling of conjoined device 300 (
An exemplary transfer chamber according to
According to the exemplary embodiment illustrated in
According to the exemplary embodiment illustrated in
As may be illustrated in
According to the illustrative embodiment of
In an exemplary embodiment, engagement between spring 460 and bottom plate 405 may be due to the placement of spring 460 in seat 410. According to the illustrative embodiment of
As illustrated in
According to an exemplary embodiment, when lock 417 holds top plate 415 in place over bottom plate 405 it may prevent movement of mounts 407 from rotating or other translational displacement. Alternatively, spring receptor 420 may contain a spring-loaded device 470 in addition to spring 460 that may store potential energy when in a compressed state. As illustrated in
While spring 460 may be shown as a coiled spring about pivot device 435 (as shown in the illustrative embodiment of
In another exemplary embodiment as illustrated by
In yet another exemplary embodiment, spring 460 may be configured to have a combination of rotational and translational resiliencies. Thus, a spring 460 may be compressed so that there is a sealing abutment of top plate 415 and bottom plate 405 such that their surfaces 416 and 406, respectively, face one another in their most proximal positions. Once the compressive forces on spring 460 are relieved, spring 460 may impart through its translational resiliency a displacement between top plate 415 and bottom plate 405 so that the sealing abutment is removed. Additionally, the translational resilience may cause surfaces 416 and 406 to grow distal from each other while remaining substantially face to face. At substantially the same time, spring 460 may impart through its rotational resiliency a rotation of one of bottom plate 405 and top plate 415 away from the other so that surfaces 416 and 406 are no longer facing one another.
In a preferred embodiment, spring 460 may be a 180° spring coiled about the cylindrical surface of a pivot device 435. As coiled, a preferred spring 460 may be compressed, for example by the locking of transfer chamber 400 using locks 417 over mounts 407, and thereby allow for a sealing engagement between top plate 415 and bottom plate 405 about gasket 430 (which may be an O-ring). Locks 417 placed over mounts 407 may also resist the rotational resiliencies of coiled spring 460. Upon unlocking a transfer chamber 400 with a preferred coiled spring 460, gasket 430 exits the complementary surface slot 419 or 409 removing the sealing engagement between bottom plate 405 and top plate 415. The coiled spring 460 may rotate bottom plate 405 and/or top plate 415 so that the surfaces 406 and 416 of the top and bottom plates, respectively, are no longer facing one another.
When pivot device 435 operatively connects top plate 415 to bottom plate 405, a sealing abutment may be formed by virtue of gasket 430 in complementary surface 409, slot 419, or both. The contents within transfer chamber 400 on surfaces 406 or 416 may be excluded from a pressurized environment to be transported to a different pressured environment.
An exemplary operation of a transfer chamber according to the embodiments of
In
In
According to the illustrative embodiment of
In
In a preferred embodiment based on
In one exemplary scenario, enclosure top 415 and enclosure bottom 405 may be held together by spindle 435. A gasket 430 between the top 415 and bottom 405 enclosures may provide a substantially air-tight seal. A spring-loaded pin 470 may be found in spring receptor 420 in enclosure bottom 415 adjacent slot 418, which may be shaped to receive spindle 435. Spring-loaded pin 470 enables enclosure top 405 to separate from abutting surface of enclosure top 415. One or more side locks 417 may be used to hold top piece 415 and bottom piece 405 together against swinging torque exerted by spring 460. The exemplary combination of components described may be utilized to allow easy handling of enclosure device 400 during pumping processes, for example, utilizing valve 413.
In another exemplary scenario, an enclosure device 400 having a vacuum seal can be self-opened in a deposition system vacuum chamber with both face down and face-up geometries by action of spring loaded pin 470, coil spring 460, and spindle 435. In a preferred embodiment, enclosure device 400 may be used in machining and testing in vacuum deposition process chamber and atomic layer deposition process chamber.
While the disclosed transfer chambers provide for upward or downward access to a mounted sample, there are no limitations to the orientation of the transfer chamber, so long as its components are provided ample clearance to perform their described functions. For example, an exemplary transfer chamber may be mounted with its back plate perpendicular to a static surface and providing sideway access to a mounted sample. In particular, transfer chambers 100, 200, and 400 may be utilized in the aforementioned orientation in providing access to a mounted sample.
Each of the various transfer chambers described may operate via naturally occurring pressure differentials and need not require dedicated pumps or feed-throughs from either mechanical or electrical devices. Each of the various transfer chambers disclosed may be suitable for use with various vacuum deposition methods because of their capability to be constructed at smaller geometries, which would accommodate process chamber designs for atomic layer depositions and/or provide for upward-facing or downward-facing sample placements when used in conjunction with evaporator systems.
Bottom plate 405 and top plate 415 may be shaped in any way or form known to those skilled in the art to provide suitable containers for a given sample and a given application. In an exemplary embodiment, bottom plate 405 and top plate 415 may be substantially the same shape so as to provide a continuous enclosure between surfaces 406 and surfaces 416. Alternatively, one of bottom plate 405 or top plate 415 may have a larger face than the other so as to provide for one or more sealing components such as gasket 430 to fit in slots 409 and/or 419.
In a preferred embodiment, bottom plate 405 and top plate 415 may be tear-drop shaped so that the substantially circular portions may hold the sample and engage in sealing the space about the sample and the narrower portion may be dedicated to the pivotability and spring activities disclosed for an exemplary transfer device.
It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description and interrelated disclosures of the various disclosed embodiments and figures. Indeed, those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described. Such equivalents are intended to be encompassed by the following claims. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
Claims
1. An enclosure device, comprising:
- a first plate having a first surface configured to receive a sample and a second surface opposite the first surface;
- a second plate having a first surface and a second surface opposite the first surface;
- a sealing component disposed on one of the first surface of the first plate and the first surface of the second plate; and,
- a pivotable link coupling the first plate to the second plate, the pivotable link configured to hold the first plate, the second plate, and the sealing component together to create an air-tight seal between the first surface of the first plate and the first surface of the second plate, and separate the first plate from the second plate when the pressure between the first surface of the first plate and the first surface of the second plate exceeds the pressure on the second surface of the first plate and the second surface of the second plate.
2. The enclosure device of claim 1, wherein the sealing component is an O-ring.
3. The enclosure device of claim 1, wherein the sample is within range of being processed by a means for sample processing when the enclosure device is opened.
4. The enclosure device of claim 1, wherein the sample is not within range of being processed by a means for sample processing when the enclosure device is opened.
5. The enclosure device of claim 3, wherein the sample is a metal substrate.
6. The enclosure device of claim 1, wherein the pivotable link comprises a hinge rotatably coupling the second plate to the first plate.
7. The enclosure device of claim 5, wherein the hinge further comprises a spring.
8. The enclosure device of claim 1, wherein the pivotable link comprises a spindle about which one of the first plate and the second plate rotates and translates.
9. The enclosure device of claim 7, wherein the pivotable link further comprises a spring.
10. The enclosure device of claim 8, wherein the spring circumscribes the spindle and couples the first plate and the second plate.
11. The enclosure device of claim 9, wherein the pivotable link further comprises a spring-loaded pin configured to translate one of the first plate and the second plate about the spindle.
12. A method for sample processing, comprising:
- (a) closing a chamber comprising a first plate having an exterior surface and an interior surface, wherein the interior surface of the first plate is configured to hold a sample, a second plate having an exterior surface and an interior surface, sealing means disposed on the interior surface of one of the first plate and the second plate, pivot means coupling the first plate to the second plate and about which the interior surface of the first plate sealingly engages the interior surface of the second plate in conjunction with the sealing means to form an air-tight seal;
- (b) subjecting the chamber to a lower pressure on the exterior surface of the first plate and the second plate; and,
- (c) displacing the second plate from the first plate about the pivot means to open the chamber.
13. The method of claim 12, wherein the displacing step further includes rotating the second plate in a plane parallel to the interior surface of the first plate about the pivot means.
14. The method of claim 13, wherein the displacing step further includes translating the second plate about the pivot means in a direction distal from and in a plane perpendicular to the interior surface of the first plate.
15. The method of claim 14, wherein the rotating step comprises rotating the second plate about a spindle circumscribed by a spring wherein a torque induced by the spring rotates the second plate about the spindle.
16. The method of claim 15, wherein the translating step comprises vertically shifting along a spindle circumscribed by a spring wherein the second plate moves distally from the first plate by an expansion of the spring.
17. The method of claim 15, wherein the translating step comprises vertically shifting along a spindle the second plate distally from the first plate by an expansion of a spring-loaded pin coupled to one of the first and the second plates.
18. The method of claim 13, wherein the displacing step comprises:
- (i) rotating the second plate in a plane parallel to the interior surface of the first plate about the pivot means; and,
- (ii) translating the second plate about the pivot means in a direction distal from and in a plane perpendicular to the interior surface of the first plate.
19. A method of sealing an atomic layer deposition transfer chamber, comprising the steps of:
- (a) pressurizing a first plate comprising a top surface and a bottom surface, the bottom surface comprising a plurality of legs and a second plate comprising a bottom surface, a mounting surface, and a sealing mechanism disposed on the mounting surface, the mounting surface configured to hold a sample, wherein the sealing mechanism forms an air-tight seal between the second plate and the bottom surface of the first plate via the sealing mechanism; and
- (b) depressurizing the first plate and the second plate to decouple the second plate from the bottom surface of the first plate.
20. The method of claim 19, wherein the maximum height from the top surface of the first plate to the ends of the plurality of legs is less than about 5 millimeters.
21. The method of claim 19, wherein during the pressurizing step, the bottom surface of the second plate is suspended at least 1 millimeter from any other parallel surface.
22. A device for creating an air-tight seal, comprising:
- a first plate having an outside and an inside;
- a second plate having an outside and an inside, wherein the inside of the second plate is disposed above the inside of the first plate;
- a sealant disposed on one of the inside of the first plate and the inside of the second plate;
- wherein the first plate forms an air-tight coupling with the second plate about the sealant exclusively by a positive pressure gradient between the outside and the inside of at least one of the first plate and the second plate.
23. The device of claim 22, wherein a negative pressure gradient between the outside and the inside of at least one of the first plate and the second plate exclusively removes the substantially air-tight seal.
24. The device of claim 22, wherein the second plate is disposed above the inside of the first plate by a plurality of legs extending distally from the second plate to elevate the outside surface of the first plate.
25. The device of claim 23, wherein the negative pressure gradient releases the first plate from the inside of the second plate.
26. The device of claim 24, wherein the plurality of legs circumscribe the first plate.
27. The device of claim 26, wherein 3 or more legs extend distally from the second plate.
28. The device of claim 25, wherein the negative pressure gradient releases the first plate from the inside of the second plate whereby the first plate traverses a length of at least one leg extending distally from the inside of the second plate.
Type: Application
Filed: Oct 4, 2013
Publication Date: Apr 10, 2014
Applicant: Brookhaven Science Associates, LLC (Upton, NY)
Inventors: Danvers E. Johnston (Lakeland, FL), Jonathan E. Allen (Philadelphia, PA), Edward Baker (Winfield, KS), Charles T. Black (New York, NY), Chang-Yong Nam (Coram, NY)
Application Number: 14/045,890
International Classification: B65D 6/00 (20060101);