Cassette lid opening device

Cassette lid opening device for a semiconductor substrate processing apparatus comprising a housing, a door assembly, a transport mechanism, and at least one suspension. The housing has at least one wall with an associated wall opening. The door assembly comprises at least one door plate configured for substantially closing off the associated wall opening of the at least one wall. The transport mechanism includes a carriage which is connected to the door assembly and configured to transport the door assembly parallel to the at least one wall. The at least one suspension is arranged between the at least one door plate and the transport mechanism. The at least one suspension comprises a suspension spring assembly which allows movement of the at least one door plate in a direction perpendicular to the at least one wall.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to a cassette lid opening device for a semiconductor substrate processing apparatus.

BACKGROUND

In clean room environments, typically wafer cassettes are used to transport wafers to and from semiconductor substrate processing apparatuses, such as vertical batch furnaces. A wafer cassette may be placed against a cassette lid opening device which may be arranged between a first environment, e.g., a cassette handling space, and a second environment, e.g., a wafer handling space of a semiconductor processing apparatus. The cassette lid opening device may comprise a wall having a wall opening for transferring wafers therethrough between the first and the second environments. The cassette lid opening device may have two functions.

A first function may be to gas sealingly separate the first environment from the second environment both when no cassette is placed against the cassette lid opening device as well as during the time that a cassette is placed against the cassette lid opening device. To that end, the cassette lid opening device may comprise a door assembly. The door assembly may be transportable by means of a transport mechanism between a first position in front of the wall opening and a second position laterally away from the wall opening so as to allow passage of wafers through the wall opening.

A second function of the cassette lid opening device may be to engage a cassette lid of a cassette which may be placed against the cassette lid opening device and to laterally move away the cassette lid while moving the door assembly to the second position, so as to open the cassette and the wall opening and allow passage of wafers through the wall opening. In known cassette lid opening devices the transport mechanism for transporting the door assembly and/or the cassette lid may be of high precision and robust so as to be able to be able to withstand high forces which may be exerted during gas sealingly closing off the wall opening.

SUMMARY

It may be an object to provide a cassette lid opening device in which the requirements for the transport mechanism of the door assembly and/or cassette lid in terms of high precision and robustness may be less strict.

To that end, there may be provided a cassette lid opening device according to claim1. More particularly, there may be provided a cassette lid opening device for a semiconductor substrate processing apparatus. The cassette lid opening device may comprise a housing, a door assembly, a transport mechanism, and at least one suspension. The housing may have at least one wall with an associated wall opening. The door assembly may comprise at least one door plate configured for substantially closing off the associated wall opening of the at least one wall. The transport mechanism may include a carriage which is connected to the door assembly and may be configured to transport the door assembly parallel to the at least one wall between a first position in front of the associated wall opening and a second position laterally away from the associated wall opening so as to allow passage of wafers through the associated wall opening. The at least one suspension may be arranged between the at least one door plate and the transport mechanism. The at least one suspension may comprise a suspension spring assembly which allows movement of the at least one door plate in a direction perpendicular to the at least one wall.

Various embodiments are claimed in the dependent claims, which will be further elucidated with reference to an example shown in the figures. The embodiments may be combined or may be applied separate from each other.

DETAILED DESCRIPTION

In this application similar or corresponding features are denoted by similar or corresponding reference signs. The description of the various embodiments is not limited to the examples shown in the figures and the reference numbers used in the detailed description and the claims are not intended to limit the description of the embodiments, but are included to elucidate the embodiments.

Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below. The illustrations presented herein are not meant to be actual views of any particular material, structure, or device, but are merely idealized representations that are used to describe embodiments of the disclosure.

As used herein, the term “wafer” may refer to any underlying material or materials that may be used, or upon which, a device, a circuit, or a film may be formed.

In the most general terms the present disclosure may provide a cassette lid opening device10. The cassette lid opening device10may be configured for use in a semiconductor substrate processing apparatus. The cassette lid opening device10may comprise a housing12, a door assembly14, a transport mechanism16, and at least one suspension22,44. The housing12may have at least one wall30,34with an associated wall opening32,36. The door assembly14may comprise at least one door plate40,42configured for substantially closing off the associated wall opening32,36of the at least one wall30,34.

The transport mechanism16may include a carriage18which is connected to the door assembly14and may be configured to transport the door assembly14parallel to the at least one wall30,34between a first position in front of the associated wall opening32,36and laterally away from the associated wall opening32,36so as to allow passage of wafers through the associated wall opening32,36.

The at least one suspension22,44may be arranged between the at least one door plate40,42and the transport mechanism16. The at least one suspension22,44may comprise a suspension spring assembly20which allows movement of the at least one door plate40,42in a direction perpendicular to the at least one wall30,34.

Generally, an inflatable seal62(seeFIGS.1,5and6) may be provided between the door assembly, in particular a first door plate40thereof, and the first wall32of the housing. In order to ensure a gas tight seal, the inflatable seal62may be inflated. In the prior art cassette lid opener, the forces exerted by the inflatable seal on the door assembly were accommodated by the transport mechanism16of the door assembly14, in particular the carriage18and the guide rail70. In view of the high forces exerted by the inflatable seal, the carriage18and the guide rail70of the known cassette lid opening device had to be robust and also highly precise. The precision was required to maintain the door assembly14parallel to the at least one wall30,34so as to ensure substantially evenly distributed closing pressure being exerted on the door assembly14along the entire circumference of the door assembly14by the inflatable seal62.

With the cassette lid opening device10according to the description, the at least one suspension22,44may ensure proper engagement between the at least one door plate40,42and the at least one wall30,34, even when the transport mechanism16does not have the aforementioned high precision and robustness. Because of the suspension spring assembly20, the at least one door plate40,42may be movable with respect to the transport mechanism16in the direction perpendicular to the at least one wall30,34. This means that the transport mechanism16only may need to position the at least one door plate40,42in a plane parallel to the at least one door plate40. Any inaccuracy in the direction perpendicular to the at least one wall3034, may be accommodated by the allowed movement of the at least one door plate40,42by the suspension spring assembly20. Forces exerted on the door assembly14in a direction perpendicular to the at least one wall30,34may be limited because these are not completely transferred to the transport mechanism16due to the presence of the suspension22,44which comprises a spring assembly20.

In an embodiment the at least one suspension22,44may comprise a door assembly suspension22. The suspension spring assembly20of the door assembly suspension22may comprise two parallel blade springs24which are each connected with a first longitudinal edge26to the carriage18and which are each connected with a second longitudinal edge28to the door assembly14.

The two parallel blade springs24may enable a movement of the door assembly14with respect to the carriage18in a single direction, namely perpendicular to the at least one wall30,34. During this movement of the door assembly14, the door assembly14will remain parallel to the at least one wall due to the parallel blade spring24assembly.

In an embodiment, of which an example is shown in the figures, the at least one wall30,34of the housing12may comprise a first wall30and the at least one wall opening32,36may comprise a first wall opening32in the first wall30. The at least one door plate40,42may comprise a first door plate40configured to substantially close off the first wall opening32.

A circumferential inflatable seal62may be positioned between the door assembly14and the first wall30of the housing12. The circumferential inflatable seal62may surround the first wall opening32and may have a deflated state in which the seal62does not engage with at least one of the first door plate40and the first wall30. In an inflated state the circumferential inflatable seal62may sealingly engage with the first wall30and the first door plate40and pushes the door assembly14against the spring force of the suspension spring assembly20of the door assembly suspension22away from the first wall30.

In a further elaboration of this embodiment, the door assembly may comprise at least one hard stop64for engaging a stop engagement point which is fixed relative to the housing12so as to limit the movement of the door assembly14induced by the inflatable seal62when being pushed away from the first wall30.

In an embodiment, of which an example is shown in the figures, the at least one hard stop64may comprise three or more hard stops64which engage on different stop engagement points of the housing12. When the door assembly14may be pushed with the hard stops64thereof against the stop engagement points of the housing12, the position of the door assembly14, relative to the housing may be well defined and the first door plate40of the door assembly14may be positioned exactly parallel to the first wall30. Additionally, the forces exerted by the inflatable seal62on the door assembly14may be absorbed by the housing12via the hard stops64and the stop engagement points of the housing12. Thus, these forces do not have to be absorbed by the transport mechanism16. In fact, the parallel blade springs24of the door assembly suspension22may limit transfer of the forces that are exerted by the inflatable seal62on the door assembly14to the transport mechanism16.

In an embodiment, the circumferential inflatable seal62may be connected to the first wall30. Such a construction may be advantageous because the inflatable seal62may be stationary mounted instead of moveable, which would be the case when the inflatable seal were connected to the first door plate40of door assembly14. Inflating a stationary seal62may be more convenient than inflating a moveably mounted inflatable seal62.

In an embodiment the at least one wall30,34of the housing12may comprises a first wall30and a second wall34which may be substantially parallel to each other. The at least one wall opening32,36may comprise a first wall opening32in the first wall30and a second wall opening36in the second wall34. The first wall opening32may be aligned with the second wall opening36so as to allow passage of a wafer through the first and the second wall openings32,36along a central wall opening axis38which extends substantially perpendicular to the first wall30through a center of the first wall opening32. The at least one door plate40,42may comprise a first door plate40configured to substantially close off the first wall opening32and a second door plate42configured to substantially close off the second wall opening36.

The at least one suspension22,44may comprise a second door plate suspension44which supports the second door plate42. The second door plate suspension44may comprises an actuator assembly46configured to effect movement of the second door plate42relative to the first door plate40in a direction substantially perpendicular to the second wall34towards and away from the second wall34. The spring assembly20of the second door plate suspension44may constitute a part of the actuator assembly46.

The cassette lid opening device10may be used to seal of a first environment of the semiconductor substrate processing apparatus, and a second environment of the semiconductor substrate processing apparatus. By virtue of the actuator assembly46, the second door plate suspension44may be able to move the second door plate42in a direction substantially perpendicular to the second wall.34. The second door plate42may thus be able to substantially close of the second wall opening36, so that the aforementioned first and second environments of the semiconductor substrate processing apparatus are substantially closed off from each other.

Additionally, the second door plate42may be used to engage a lid of a wafer cassette and with the movement of the second door plate42remove the lid from the cassette and subsequently, with the movement of the door assembly transport the lid laterally away from the cassette. Because of the spring assembly20which may constitute a part the actuator assembly, the accuracy requirements of the other parts of the actuator assembly46may be less stern. Any inaccuracy of the other parts of the actuator assembly46causing a possible overshoot of the movement of the second door plate42may be compensated by compression of the spring assembly20of the second door plate suspension44.

In an embodiment, the second door plate suspension44may comprise at least one second door plate guide45for guiding the movement of the second door plate42in the direction substantially perpendicular to the second wall34towards and away from the second wall34. The actuator assembly46may be configured as a toggle lever assembly48which may be operatively connected with a toggle lever assembly motor50of which an example is visible inFIGS.9and10.

By actuating the toggle lever assembly motor50the toggle lever assembly48may be operated such that the second door plate42may be moved relative to the first door plate40.

In an embodiment, the toggle lever assembly48may include at least one first toggle lever52which may pivotally connected with the first door plate40and at least one second toggle lever54which may be hingedly connected to the spring assembly20. In that embodiment, the second door plate42may be connected to the spring assembly20.

In a further elaboration of that embodiment, the spring assembly20of the second door plate suspension44may include at least one blade spring56which at a first position58may be connected with the second toggle lever54of the toggle lever assembly48. The second door plate42may be connected to a second position60of the at least one blade spring56so that, in a position of the toggle lever assembly48which corresponds to a closed position of the second door plate42, the at least one blade spring56may bias the second door plate42against the second wall34.

As shown in the example ofFIG.5, the first position58at which the second toggle lever54may be connected with the blade spring56may be at a free end of the at least one blade spring56. The second position60may be at a middle section of the at least one blade spring56. In this example, the second door plate42may connected to a bracket74which may connected at the second position60with an associated one of the at least one blade spring56. In the example, the spring assembly20of the second door plate suspension44may comprise two blade springs56and two brackets positioned near opposite ends of the second door plate42.

In this way the toggle lever assembly48may move the spring assembly20from and towards the first door plate40. With the spring assembly20the second door plate42may be moved also. When the second door plate42reaches the second wall34, further movement by the toggle lever assembly48may result in compressing of the spring assembly20. The movement of the second door plate42by the toggle lever assembly48towards the second wall34thus does not have to be very precise. Any impreciseness may be accommodated by the compression of the spring assembly20.

FIGS.13and14show an example of an alternative embodiment of the second door plate suspension44. For the sake of clarity, the first door plate40is not shown inFIGS.13and14but this first door plate40may have substantially the same configuration as the first door plate40shown in e.g.FIGS.5,6and11. The first door plate40is connected to connecting fixtures106which are shown inFIGS.13and14. As in the embodiment shown inFIGS.5,6,9,10and11, again also in the embodiment shown in the example ofFIGS.13and14, the second door plate suspension may comprise at least one second door plate guide45for guiding the movement of the second door plate42in the direction substantially perpendicular to the second wall34towards and away from the second wall34. The actuator assembly46may be configured as an integrally formed compliant mechanism90which may connect the first door plate40with the second door plate42. The integrally formed compliant mechanism90may incorporating the spring assembly20of the second door plate suspension44. The integrally formed compliant mechanism90may be operatively connected with a compliant mechanism drive motor92.

Complaint mechanisms rely on their inherent elasticity to make the movements and do not require multiple moving parts. Thus, the number of metal on metal contacts may be minimized and may even be completely absent in the integrally formed compliant mechanism. An advantage of an integrally formed compliant mechanism may be that the release of particles may be minimized because no bearings or moving contact interfaces between separate parts are present in the integrally formed compliant mechanism. In fact, the integrally formed compliant mechanism may consist of a single piece which may be injection molded from a plastic material.

In an embodiment, the integrally formed compliant mechanism90may be a bi-stable compliant mechanism having two stable positions. In a first position the first door plate40may be at a first distance from the second door plate42. In a second position the first door plate40may at a second distance from the second door plate42, which second distance differs from the first distance.

A bi-stable integrally formed compliant mechanism may be relatively simple and may have the advantage that no force has to be exerted on the bi-stable mechanism when it has assumed one of the first and the second positions. Thus, the compliant mechanism drive motor92only has to be activated very briefly to bring the integrally formed compliant mechanism90for the first position to the second position and vice versa.

In an embodiment, the integrally formed compliant mechanism90may comprise flexible door plate connection links94which connect the first door plate40with the second door plate42. The flexible door plate connection links94may integrally connected via an integrally formed linkage assembly96,98,100,102to the compliant mechanism drive motor92as is clearly shown in the example ofFIGS.13and14.

The integrally formed linkage assembly96,98,100,102may comprise at least one first link96which is connected to an associated one of the door plate connection links94. Further, the linkage assembly may comprise at least one second link98of which a first end98amay be hingedly connected to a fixed frame part108of the cassette lid opening device. A second end98bof the second link98may be connected via a integrally formed hinge100to a first end102aof a third link102. A second end102bof the third link102may be connected via a flexible hinge104to a rotor arm106of the integrally formed compliant mechanism90. The rotor arm may be connected to a rotatable drive shaft108of the drive motor92.

It should be noted that the example shown inFIGS.13and14is just one example of the many possibilities in which an integrally formed compliant mechanism90may be configured. The spring action of the integrally formed compliant mechanism is incorporated in the flexible structure of the compliant mechanism and is also a result of the chosen material of which the compliant mechanism90has been manufactured. The absence of sliding metal to metal contact points in the mechanism minimizes the release of particles which is an important advantage of the integrally formed compliant mechanism embodiment.

In an embodiment as shown inFIG.12, the second door plate42may comprise cassette lid engagers66, configured to engage a lid of a cassette. In use, the lid of the cassette may be removed from the cassette by movement of the second door plate42towards the first door plate40and subsequently transporting the door assembly14from the first position to the second position laterally away from the second wall opening36.

The cassette may comprise a plurality of stacked wafers. The cassette lid opening device10may thus be used to open the cassette by removing the lid of the cassette. When the door assembly14is moved laterally away from the second wall opening32, the wafers in the cassette may be reached through the first and second wall openings32,36. The cassette lid engagers66may be embodied as a twistlocks, grippers, suction cups or another engager known in the field.

As shown in the example inFIGS.8and11, the second door plate42may comprise a circumferential cassette lid seal78which, in use, is positioned between the second door plate42and the lid of the cassette for sealingly engagement with the second door plate42and the lid of the cassette. The cassette lid seal78may be used to create a low pressure chamber between the second door plate42and the lid of the cassette, which may be used to attach the lid of the cassette to the second door plate42.

As visible in the example shown inFIGS.7and11, the second wall34may comprise a cassette body seal80which, in use, is positioned between the second wall34and a body of the cassette for sealingly engagement with the second wall34and the body of the cassette.

In an embodiment a second circumferential seal68may be positioned between the second wall34and the second door plate42and may surround the second wall opening36. The second circumferential seal68may substantially close off the second wall opening36when the actuator assembly46configured to effect movement of the second door plate42relative to the first door plate40has been actuated to move the second door plate42towards the second wall34so that the spring assembly20of the second door plate suspension44is spring loaded.

The actuator assembly46may thus press the second circumferential seal68with the second door plate42to the second wall34. By virtue of the spring assembly20of the second door plate suspension44, the actuator assembly46may be prevented from pushing too hard or too far, because trying to do so may result in compressing the spring assembly20and not in damage of the second wall34or actuator assembly46or other parts of the cassette lid opening device10.

The second circumferential seal68may connected to the second door plate42. Alternatively, the second circumferential seal68may also be connected to the second wall34.

In an embodiment the transport mechanism16may comprise a guide rail70fixedly connected to the housing12. The carriage18may moveably connected to the guide rail70and may be moveable along a guide rail axis72defined by the guide rail70. A spindle82connected to a drive motor76may effect movement of the carriage along the guide rail70. The guide rail axis72may be substantially parallel to the at least one wall30,34.

The guide rail70may thus be able to allow movement of the carriage18, and thus the door assembly14, substantially parallel with respect to the at least one wall30,34.

Although illustrative embodiments of the present invention have been described above, in part with reference to the accompanying drawings, it is to be understood that the invention is not limited to these embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

Furthermore, it is noted that particular features, structures, or characteristics of one or more of the various embodiments which are described above may be used implemented independently from one another and may be combined in any suitable manner to form new, not explicitly described embodiments. The reference numbers used in the detailed description and the claims do not limit the description of the embodiments, nor do they limit the claims. The reference numbers are solely used to clarify.

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