Actuator to adjust dynamically showerhead tilt in a semiconductor-processing apparatus
In various embodiments, a showerhead mechanism to adjust a showerhead in a semiconductor substrate-processing apparatus is disclosed. The mechanism includes at least one actuator assembly that is dynamically operable to adjust parallelism of a faceplate of the showerhead with reference to an upper surface of a substrate pedestal that is to be positioned adjacent to the faceplate. Each of the actuator assemblies includes a piezoelectric stack and a lever having a first end and a second end. The lever is mechanically coupled on the first end to the piezoelectric stack and on the second end to the showerhead to displace the showerhead in at least one direction of tilt. The lever is operable to amplify mechanically a displacement of the piezoelectric stack. A lever pivot point is coupled to the lever and is located between the first end and the second end of the lever.
1. A showerhead adjustment mechanism to adjust a showerhead in a semiconductor substrate-processing apparatus, the showerhead adjustment mechanism comprising:
at least one actuator assembly that is dynamically operable to adjust parallelism of a faceplate of the showerhead with reference to an upper surface of a substrate pedestal to be positioned adjacent to the faceplate, each of the at least one actuator assemblies including:
a piezoelectric stack;
a lever having a first end and a second end, the lever being mechanically coupled on the first end to the piezoelectric stack and on the second end to the showerhead to displace the showerhead in at least one direction of tilt, the lever being operable to amplify mechanically a displacement of the piezoelectric stack;
a socket in the second end of the lever to act on a ball joint coupled to the showerhead dynamically to move the showerhead in at least one direction of tilt; and
a lever pivot coupled to the lever and located between the first end and the second end of the lever.
2. The showerhead adjustment mechanism of claim 1 , wherein the adjustment of the showerhead is to control at least one gap distance between the faceplate of the showerhead and the upper surface of the substrate pedestal.
3. The showerhead adjustment mechanism of claim 2 , further comprising at least one in-situ sensor to measure the at least one gap distance and the parallelism of the faceplate with reference to the upper surface of the substrate pedestal.
4. The showerhead adjustment mechanism of claim 1 , wherein the lever pivot comprises a blade flexure to act as a frictionless fulcrum based on elastic deformation of a solid material.
5. The showerhead adjustment mechanism of claim 1 , wherein a gain ratio of the lever is between about 2:1 and about 20:1.
6. The showerhead adjustment mechanism of claim 1 , wherein a gain ratio of the lever is about 6.5:1.
7. The showerhead adjustment mechanism of claim 1 , wherein each of the at least one actuator assemblies correlates to at least one degree-of-freedom of movement.
8. The showerhead adjustment mechanism of claim 1 , further comprising a flexure mount coupled between the first end of the piezoelectric stack and the first end of the lever.
9. The showerhead adjustment mechanism of claim 1 , wherein the parallelism of the faceplate of the showerhead with reference to the upper surface of a substrate pedestal is to be adjusted from outside of a reaction chamber in which the showerhead is located without breaking a level of vacuum of the reaction chamber.
10. The showerhead adjustment mechanism of claim 1 , wherein the adjustment is configured to be made between subsequent process steps on a substrate mounted to the substrate pedestal.
11. The showerhead adjustment mechanism of claim 1 , wherein the showerhead adjustment mechanism is configured dynamically to adjust a position of the faceplate of the showerhead with a resolution of less than 0.15 milliradians.
12. The showerhead adjustment mechanism of claim 1 , wherein the lever pivot is located on a side of lever that is on a side opposite to a point of contact between the first end of the piezoelectric stack and the lever.
13. A showerhead adjustment mechanism to adjust a showerhead in a semiconductor substrate-processing apparatus, the showerhead adjustment mechanism comprising:
at least one actuator assembly that is dynamically operable to adjust parallelism of a faceplate of the showerhead with reference to an upper surface of a substrate pedestal to be positioned adjacent to the faceplate, each of the at least one actuator assemblies including:
a piezoelectric stack;
a lever having a first end and a second end, the lever being mechanically coupled on a first end to the piezoelectric stack and including a socket on the second end to the showerhead to displace the showerhead in at least one direction of tilt, the lever being operable to mechanically amplify a displacement of the piezoelectric stack;
a socket in the second end of the lever to act on a ball joint coupled to the showerhead dynamically to move the showerhead in at least one direction of tilt; and
a blade flexure to act as a frictionless fulcrum based on elastic deformation of a solid material, the blade flexure being coupled to the lever and located between the first end and the second end of the lever.
14. The showerhead adjustment mechanism of claim 13 , wherein the piezoelectric stack comprises a material whose length increases substantially linearly with an increase in applied voltage.
15. The showerhead adjustment mechanism of claim 13 , wherein the lever is to amplify a range of motion of the showerhead by at least about 2:1.
16. The showerhead adjustment mechanism of claim 13 , wherein the lever is to amplify a range of motion of the showerhead by at least about 4:1.
17. The showerhead adjustment mechanism of claim 13 , wherein the lever is to amplify a range of motion of the showerhead by at least about 6.5:1.
18. A showerhead adjustment mechanism to adjust a showerhead in a semiconductor substrate-processing apparatus, the showerhead adjustment mechanism comprising:
at least one actuator assembly that is dynamically operable to adjust parallelism of a faceplate of the showerhead with reference to an upper surface of a substrate pedestal to be positioned adjacent to the faceplate, each of the at least one actuator assemblies including:
a piezoelectric stack;
a lever having a first end and a second end, the lever being mechanically coupled on the first end to the piezoelectric stack and on the second end to the showerhead to displace the showerhead in at least one direction of tilt, the lever being operable to mechanically amplify a displacement of the piezoelectric stack;
a socket in the second end of the lever to act on a ball joint coupled to the showerhead dynamically to move the showerhead in at least one direction of tilt; and
a lever pivot coupled to the lever and located between the first end and the second end of the lever; and
at least one in-situ sensor to measure a gap distance and the parallelism of the faceplate with reference to the upper surface of the substrate pedestal.
19. The showerhead adjustment mechanism of claim 18 , wherein the at least one in-situ sensor includes at least one sensor selected from sensors including a laser interferometer, a linear variable differential transformer, and one or more strain gauge sensors.