Wafer stage for symmetric wafer processing
View Patent ↗A planetary arm coupled to a tilt actuator moves a wafer in oscillatory motion along an arcuate path to expose a surface of the wafer to an incident ion beam for deposition and/or etching processing of thin film structures on the surface of the wafer. A wafer holder on an end of the planetary arm may be driven in rotation while the planetary arm executes oscillatory motion at a selected tilt angle relative to an incident ion beam. A slit support plate provides controllable exposure of the wafer to the incident beam. Embodiments are suitable for use in wafer deposition machines and/or wafer etching machines.
1. A planetary scan wafer stage, comprising:
a tilt actuator;
a planetary arm rotatably coupled to said tilt actuator;
a slit support plate attached to said tilt actuator;
a wafer holder rotatably coupled to said planetary arm; and
a planetary scan actuator attached to said tilt actuator and to said planetary arm,
wherein said planetary arm and said slit support plate are rotatable to a selected tilt angle by said tilt actuator and said planetary arm is movable along an arcuate path by said planetary scan actuator.
2. The planetary scan wafer stage of claim 1 , further comprising a wafer rotation drive attached to said planetary arm, wherein said wafer rotation drive is coupled to said wafer holder for rotation of said wafer holder.
3. The planetary scan wafer stage of claim 1 , wherein said arcuate path is a circular arc of constant radius.
4. The planetary scan wafer stage of claim 1 , wherein an oscillatory motion of said planetary arm along said arcuate path and a rotational motion of said wafer holder are capable of coordinated rotation for symmetric processing of thin film structures on a wafer workpiece held in said wafer holder.
5. The planetary scan wafer state of claim 1 , wherein said tilt actuator comprises a stationary collar and a core rotatably coupled to said stationary collar.
6. The planetary scan wafer stage of claim 5 , wherein said planetary arm further comprises an arm hub rotatably coupled to said core.
7. The planetary scan wafer stage of claim 5 , wherein said planetary scan actuator is attached to said core.
8. The planetary scan wafer stage of claim 5 , wherein said slit support plate is attached to said core.
9. The planetary scan wafer stage of claim 5 , further comprising a tilt actuator motor attached to said collar and disposed to drive said core in rotation relative to said collar.
10. The planetary scan wafer stage of claim 1 , wherein said slit support plate is formed with a beam aperture.
11. The planetary scan wafer stage of claim 10 , wherein said beam aperture is formed with a length greater than a diameter of a wafer held in said wafer holder.
12. The planetary scan wafer stage of claim 10 , further comprising a pair of opposing shutter plates slidably coupled to said slit support plate, wherein a separation distance between opposing edges of said opposing shutter plates is adjustable to form a slot of adjustable width.
13. The planetary scan wafer stage of claim 10 , further comprising a first shutter plate rotatably coupled to said slit support plate.
14. The planetary scan wafer stage of claim 13 , wherein said first shutter plate is formed with an aperture for admittance of a beam of particles.
15. The planetary scan wafer stage of claim 13 , wherein said aperture formed in said first shutter plate is formed with a rectangular shape.
16. The planetary scan wafer stage of claim 13 , wherein said aperture formed in said first shutter plate is formed with arcuate edges.
17. The planetary scan wafer stage of claim 13 , wherein said aperture formed in said first shutter plate is formed with opposing edges which are not parallel to one another.
18. The planetary scan wafer stage of claim 13 , further comprising an actuator coupled to said slit support plate and said first shutter plate.
19. The planetary scan wafer stage of claim 13 , further comprising a second shutter plate sized to block said beam aperture in said slit support plate.
20. The planetary scan wafer stage of claim 19 , further comprising an actuator coupled to said slit support plate and said second shutter plate.