Wafer processing machine vacuum front end method and apparatus

• US 5,516,732 A
• Filed: 12/04/1992
• Issued: 05/14/1996
• Est. Priority Date: 12/04/1992
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Materials Research Corporation (Linde Plc), Sony Corporation (Sony Group Corp.)
• Inventors: Flegal, deceased, Christopher
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): Picardat, Kevin M.
• Application Number:
  US07/985,300
• Time in Patent Office: 1,257 Days
• Field of Search: 437/250, 29/25.01, 414/935, 414/536, 414/937, 414/938, 414/939, 414/940, 414/941
• US Class Current: 438/800
• CPC Class Codes: H01L 21/67167 surrounding a central transfer chamber
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H01L 21/67748 horizontal transfer of a single workpiece
• CPC Class Codes: H01L 21/67751 vertical transfer of a single workpiece
• CPC Class Codes: Y10S 414/135 Associated with semiconductor wafer handling
• CPC Class Codes: Y10S 414/139 including wafer charging or discharging means for vacuum chamber

Abstract

A carrousel type wafer processing machine in which wafers are held in vertical orientations in holders on a rotatable plate and sequenced through a plurality of processing stations for processing, such as by the application of a sputtered film thereto, is provided with a vacuum front end module that transfers wafers between cassette modules in which the wafers are horizontally disposed and a loading and unloading station of the processing machine, through a transfer chamber. The transfer chamber includes a wafer transfer arm, an aligning station, a preheating and degassing station, a cooling station preferably combined with the preheating station, and an uprighting station from which wafers are exchanged with the processing machine. The arm moves unprocessed wafers individually from a cassette module to the aligner, then to the preheating station, then to the uprighting station. The arm also moves processed wafers from the uprighting station, to the cooling station and to a cassette module. Preferably, one cassette module is being vented, reloaded or replaced, and pumped to a vacuum while the wafers of the other are being cycled through the processing machine.

Claims

1. A wafer processing apparatus comprising:

a wafer processing machine having a main vacuum chamber therein, a plurality of workstations disposed at equally spaced angular intervals in a vertical plane around a horizontal axis in the main chamber, the plurality of workstations including a plurality of processing stations and a loading and unloading station, an index plate rotatably mounted in the main chamber and having a plurality of wafer holders mounted thereon at angular intervals about the horizontal axis such that the plate rotates to carry the holders sequentially through the workstations and to simultaneously position each of the holders at different ones of the workstations;

a transfer module having a vacuum transfer chamber therein, a plurality of treatment stations disposed in the transfer chamber, and a loading and unloading port communicating between the transfer chamber and the loading and unloading station of the wafer processing machine;

two wafer cassette loadlock chambers each containing means for supporting a plurality of horizontally disposed wafers in a vertical stack therein, and having an interior selectively connectable through a sealable port to the transfer chamber of the transfer module;

the treatment stations including;

a wafer aligning station having means thereat for establishing rotational and eccentrical alignment of a wafer positioned thereat,

a wafer preheating station having wafer heating means thereat,

a wafer cooling station having wafer cooling means thereat, and

a wafer uprighting station including means thereat for rotating a wafer thereat and carrying the wafer through the loading and unloading port between a horizontal orientation in the transfer chamber to a vertical orientation in a holder in the loading and unloading station of the wafer processing machine; and

a transfer arm in the transfer chamber operable to pickup a wafer from, and deposit the wafer at, a receiving position at each of the treatment stations and in each of the loadlock chambers and to transfer wafers among each of the receiving positions.

2. A transfer module for a wafer processing apparatus having a vacuum chamber therein, a loading and unloading station in the vacuum chamber having a holder located therein for holding a wafer in a vertical orientation, comprising:

a vacuum transfer chamber;

a radially extendable wafer transfer arm pivotal about a vertical axis within the transfer chamber;

a plurality of treatment stations disposed approximately in a horizontal plane about the vertical axis in the transfer chamber;

a loading and unloading port communicating between the transfer chamber and the loading and unloading station of the wafer processing machine;

two wafer cassette loadlock chambers each containing a rack for supporting a plurality of horizontally disposed wafers in a vertical stack therein, and having an interior selectively connectable through a sealable port to the transfer chamber;

the treatment stations including a wafer aligning station having means thereat for generating signals containing information of rotational and eccentrical alignment of a wafer positioned thereat without physically contacting the wafer;

the treatment stations also including a two section temperature treatment station, including a preheating section having wafer heating means thereat, a cooling section having wafer cooling means thereat, and a moveable wafer support for moving a wafer between a receiving position and each of the sections;

a wafer uprighting station including a platen thereat having means for holding a wafer thereto, the platen being pivotally mounted in the transfer module to swing, and carry a wafer, through the loading and unloading port between a horizontal orientation in the horizontal plane in the transfer chamber to a vertical orientation in the holder in the loading and unloading station of the machine; and

the transfer arm including an extendable member pivotally connected at an end thereof at the vertical axis and having a wafer engager at a free end thereof, the arm being operable to engage a wafer with the engager and pickup the wafer from, and deposit the wafer at, a receiving position at each of the treatment stations and in each of the racks of the loadlock chambers, and to transfer wafers among each of the receiving positions.

3. A method of handling and processing wafers comprising the steps of:

providing a plurality of horizontally oriented wafers spaced in a vertical stack in at least one cassette module, including a first cassette module, in a vacuum environment in communication with a transfer chamber;

moving a horizontally oriented wafer from the first cassette module to an aligning station in the transfer chamber and aligning the wafer thereat;

moving the aligned wafer from the aligning station to a preheating station in the transfer module and heating the wafer to degas the wafer;

moving the degassed wafer from the preheating station to an uprighting station in the transfer module;

moving the wafer from a horizontal orientation at the uprighting station through a loading port to a vertical orientation in a loading station in a wafer processing machine;

processing the wafer while in the vertical orientation in the wafer processing machine;

moving the processed wafer from the vertical orientation in the loading station of the wafer processing machine through the loading port and to a horizontal orientation at the uprighting station;

moving the wafer from the uprighting station to a cooling station in the transfer module and cooling the wafer thereat; and

moving the wafer from the cooling station to a storage position in the cassette module.

4. The method of claim 3 wherein:

the preheating station and cooling station are located in the transfer chamber;

the steps of moving the wafer to the preheating station and the cooling station include the step of moving the wafer to a receiving position at the preheating and cooling station and then moving the wafer from the receiving position to the respective heating or cooling station.

5. The method of claim 3 wherein:

the at least one cassette module further includes a second cassette module; and

the method further comprises the step of replacing a plurality of processed wafers in the second cassette module with a plurality of unprocessed wafers while wafers from the first cassette module are being processed.

6. A method of handling and processing wafers comprising the steps of:

providing a plurality of wafers each in a horizontal orientation and vertically spaced from each other in a stack in a cassette module in a vacuum environment in selective communication with a transfer chamber;

moving a wafer from the cassette module in the horizontal orientation to an aligning station in the transfer chamber and sensing the eccentric and rotational alignment of the wafer thereat;

moving the wafer in the horizontal orientation from the aligning station in angular and axial alignment at a preheating station in the transfer module and heating the wafer at the preheating station to degas the wafer;

moving the degassed wafer in the horizontal orientation from the preheating station to an uprighting station in the transfer module;

moving the wafer from the horizontal orientation at the uprighting station through a loading port to a vertical orientation in a loading station of a wafer processing machine;

processing the wafer while in the vertical orientation in the wafer processing machine;

moving the processed wafer from the vertical orientation in the loading station of the wafer processing machine through the loading port and to the horizontal orientation at the uprighting station;

moving the wafer from the uprighting station in the horizontal orientation to a cooling station in the transfer module and cooling the wafer thereat; and

moving the wafer in the horizontal orientation from the cooling station to a horizontally oriented storage position in a cassette module.

7. The method of claim 6 wherein:

the preheating station and cooling station are located in the transfer chamber and;

the steps of moving the wafer to the preheating station and the cooling station each include the step of moving the wafer to a receiving position at the preheating and cooling station and then moving the wafer from the receiving position to the respective heating or cooling station.

8. The method of claim 6 wherein:

the at least one cassette module further includes a second cassette module; and

the method further comprises the step of replacing a plurality of processed wafers in the second cassette module with a plurality of unprocessed wafers while wafers from the first cassette module are being processed.

9. A wafer processing apparatus comprising:

a wafer processing machine having a main vacuum chamber therein, a plurality of workstations spaced at equal angular intervals in a vertical plane in a circle around a horizontal axis in the main chamber, the plurality of workstations including a plurality of processing stations and a loading and unloading station, a rotatable index plate in the main chamber and having a plurality of wafer holders thereon spaced at the equal angular intervals in a circle about the horizontal axis such that, as the plate is indexed, the holders are sequentially moved through the workstations and simultaneously positioned at different ones of the workstations;

a transfer module having a vacuum transfer chamber therein, a plurality of treatment stations horizontally disposed in the transfer chamber, and a loading and unloading port communicating between the transfer chamber and the loading and unloading station of the wafer processing machine;

a plurality of wafer cassette loadlocks each having a rack support therein configured to hold a plurality of wafers in a horizontal orientation vertically spaced in a stack therein, the loadlocks having an interior selectively connectable through a sealable opening to the transfer chamber of the transfer module;

the treatment stations including;

a wafer aligning station;

a wafer preheating station having a wafer heater thereat,

a wafer cooling station having a wafer cooler thereat, and

a wafer uprighting station having an uprighting mechanism thereat configured to move a wafer carried thereby between a horizontal orientation in the transfer chamber to a vertical orientation in the loading and unloading station of the wafer processing machine; and

a transfer arm in the transfer chamber operable to pickup a wafer from, to deposit the wafer at, and to transfer wafers among selected treatment stations and loadlocks.

10. A transfer module for a wafer processing apparatus having a vacuum chamber therein, a loading and unloading station in the vacuum chamber having a holder located therein for holding a wafer in a vertical orientation, the transfer module comprising:

a vacuum transfer chamber;

a radially extendable wafer transfer arm pivotal about a vertical axis within the transfer chamber;

a plurality of treatment stations disposed approximately in a horizontal plane about the vertical axis in the transfer chamber;

a loading and unloading port communicating between the transfer chamber and the loading and unloading station of the wafer processing machine;

two wafer cassette loadlocks each containing a rack for supporting a plurality of horizontally disposed wafers in a vertical stack therein, and having an interior selectively connectable through a sealable gate to the transfer chamber;

the treatment stations including a wafer aligning station having thereat sensors for determining rotational and eccentric alignment of a wafer positioned thereat without physically contacting the wafer;

the treatment stations also including at least one temperature treatment station, including a preheating section having a wafer heater thereat and a cooling section having a wafer cooler thereat;

a wafer uprighting station having a wafer holder thereat that is pivotally mounted in the transfer module and moveable to carry a wafer, through the loading and unloading port, between a horizontal orientation in the horizontal plane in the transfer chamber to a vertical orientation in the holder in the loading and unloading station of the machine; and

the transfer arm including an extendable member pivotally connected at an end thereof at the vertical axis and having a wafer engager at a free end thereof, the arm being operable to engage a wafer with the engager and pickup the wafer from, and deposit the wafer at, a receiving position at each of the treatment stations and in each of the racks of the loadlocks, and to transfer wafers among each of the receiving positions.

11. A wafer processing apparatus comprising:

a plurality of cassette modules having a loadlock chamber therein adapted to support a vertical stack of horizontally oriented wafers and each having a gate;

a vertical carrousel type wafer processing machine having a vacuum chamber therein and a wafer loading and unloading port communicating with the vacuum chamber; and

a vacuum front end module interconnecting the cassette modules at the gates thereof and the processing machine at the port thereof, a transfer chamber therein selectively communicable with the vacuum chamber and the loadlock chambers, a moveable transfer arm therein moveable to transfer wafers in a horizontal orientation about the transfer chamber and edgewise through the gates of the cassette module, an uprighting mechanism in the transfer chamber operable to transfer wafers axially through the port and between the horizontal orientation in the transfer chamber and a vertical orientation in the processing chamber.

12. The apparatus of claim 11 wherein:

the transfer chamber contains a rotatable and extendable transfer arm mounted therein and operable to move individual wafers operable to move individual wafers horizontally to and from the loadlocks from and to the uprighting mechanism.

13. The apparatus of claim 11 wherein:

the transfer chamber has a plurality of treatment stations located therein and the transfer is operable for transferring wafers individually to and from a selected one of the treatment stations.