Multi-station sputtering and cleaning system
A multi-chamber processing system is described for depositing materials on multiple workpieces (wafers, display panels, or any other workpieces) at a time in a vacuum chamber. The system includes a sputtering chamber and a separate pre-clean chamber, where wafers can be transferred between the two chambers by a robotic arm without breaking a vacuum. The wafers are mounted one-by-one onto a rotating pallet in the pre-cleaning chamber and sputtering chamber. The pallet is firmly fixed to a rotatable table in the sputtering chamber. Copper tubing in the table couples RF energy to the wafers, and a liquid running through the copper tubing controls the temperature of the wafers. Multiple targets, of the same or different materials, may concurrently deposit material on the wafers as the pallet is rotating. Multiple magnets (one for each target) in the magnetron assembly in the sputtering chamber oscillate over their respective targets for uniform target erosion and uniform deposition on the wafers. An electrically insulated target backing plate between each magnet and a target has a liquid channel running through it for controlling temperature. The distance between the magnets and the targets is made very small by a thin aluminum plate fixed to the bottom segment of the target backing plate by a dip brazing process. Various shields are described to prevent cross-contamination from the targets and prevent the sputtered target material from entering gaps in the chamber and shorting out insulators.
1 . A processing system comprising:
at least one load lock for receiving a plurality of workpieces for processing and for storing processed workpieces, the at least one load lock being sealable for being at a low pressure significantly below ambient pressure;
a transport module connected to the at least one load lock, the transport module being sealable for being at the low pressure;
a robotic arm within the transport module for transporting the workpieces from and to the at least one load lock at the low pressure;
a cleaning chamber connected to the transport module, the cleaning chamber being sealable for being at the low pressure, the cleaning chamber comprising a first workpiece support area for supporting a plurality of workpieces at a time for batch cleaning of the workpieces using a plasma;
a sputtering chamber connected to the transport module, the sputtering chamber being sealable for being at the low pressure, the sputtering chamber comprising a second workpiece support area for supporting a plurality of workpieces at a time for batch sputtering on the workpieces, the sputtering chamber comprising a plurality of targets for sputtering target material onto the workpieces using a plasma; and
the robotic arm and system being configured so that the workpieces may be transferred from the at least one load lock, to the cleaning chamber, from the cleaning chamber to the sputtering chamber, and from the sputtering chamber to the at least one load lock without the plurality of workpieces being exposed to ambient pressure.
2 . The system of claim 1 wherein a base pressure in the cleaning chamber is lower than the pressure in the transport module during a cleaning operation.
3 . The system of claim 1 wherein a base pressure in the sputtering chamber is lower than the pressure in the transport module during a sputtering operation.
4 . The system of claim 1 wherein the sputtering chamber comprises:
a low pressure chamber;
a rotatable first pallet in the chamber, the rotatable first pallet having a plurality of workpiece support areas for concurrently supporting a plurality of workpieces on the first pallet;
a plurality of targets having sputtering surfaces facing the first pallet;
a first port for receiving workpieces one at a time for loading one at a time onto the workpiece support areas; and
a first motor for rotating the first pallet such that workpieces oppose different target sputtering surfaces at different times during sputtering operations.
5 . The system of claim 4 wherein the cleaning chamber comprises:
a low pressure cleaning chamber;
a rotatable second pallet in the cleaning chamber, the rotatable second pallet having a plurality of workpiece support areas for concurrently supporting a plurality of workpieces on the second pallet for batch cleaning of the workpieces using a plasma;
a second port for receiving workpieces one at a time for loading one at a time onto the workpiece support areas; and
a second motor for rotating the second pallet;
the robotic arm transporting cleaned workpieces one at a time from the second pallet to the first pallet in the sputtering system without exposing the workpieces to ambient pressure.
6 . The system of claim 1 wherein the cleaning chamber is an inductively coupled plasma chamber having a plasma generator.