Method of adjusting wafer shape using multi-directional actuation films
Techniques herein include methods for coating a single layer actuator film or multi-layer actuator film on the backside of a wafer. The actuator film includes one or more chemical actuators. Chemical actuators are various molecules, crystals, chemical compounds and other chemical compositions that are capable of imposing directional stress in response to application of an external stimulus on the chemical actuator. The external stimulus can include a particular wavelength of light or polarization of light, or heat (or directed infrared radiation) or load, which can include load-responsive actuation or pressure-responsive actuation.
1. A method of processing a substrate, the method comprising:
forming an actuator film on a first surface of a wafer, the wafer including the first surface and a second surface opposite the first surface, the actuator film including an actuator material, the actuator film being sensitive to a predetermined activating stimulus, the actuator film configured to undergo a positional change in response to activation of the actuator material; and
activating the actuator material in the actuator film via the predetermined activating stimulus at locations along the first surface of the wafer and causing a stress within the actuator film, the stress modifying a shape of the wafer, the stress caused within the actuator film mitigating a determined deformation stress at a location of a first structure on the first surface.
2. The method of claim 1 , wherein the first surface is a backside surface of the wafer, and the second surface includes at least partially formed structures.
3. The method of claim 1 , wherein the first surface includes at least partially formed structures and is opposite a backside surface.
4. The method of claim 3 , wherein the actuator film is formed in between each structure of the at least partially formed structures.
5. The method of claim 3 , wherein the actuator film is formed along a periphery of an area including the at least partially formed structures.
6. The method of claim 1 , wherein activating the actuator in the actuator film causes compressive stress in the actuator film.
7. The method of claim 1 , wherein activating the actuator material in the actuator film causes tensile stress in the actuator film.
8. The method of claim 1 , wherein the actuator film includes a first layer of a first actuator material and a second layer of a second actuator material.
9. The method of claim 8 , wherein the first layer of the first actuator material is responsive to a different predetermined activating stimulus than the second layer of the second actuator material.
10. The method of claim 8 , wherein the first layer of the first actuator material provides compressive stress and the second layer of the second actuator material provides tensile stress.
11. The method of claim 1 , wherein the actuator film includes a first actuator material and a second actuator material, the first actuator material being responsive to a different predetermined activating stimulus than the second actuator material.
12. The method of claim 1 , wherein activating the actuator material in the actuator film includes exposing the first surface to a pattern of light exposed using a direct-write system.
13. The method of claim 1 , wherein forming an actuator film on the first surface of the wafer further comprises;
depositing a first layer of a first actuator material on the first surface of the wafer, the first layer of the first actuator material being responsive to a first predetermined activating stimulus; and
depositing a second layer of a second actuator material on the first layer of the first actuator material, the second layer of the second actuator material being responsive to a second predetermined activating stimulus, the first predetermined activating stimulus being different than the second predetermined activating stimulus.
14. The method of claim 13 , wherein activating the actuator material in the actuator film further comprises:
activating the first layer of the first actuator material using the first predetermined activating stimulus; and
activating the second layer of the second actuator material using the second predetermined activating stimulus.
15. The method of claim 13 , wherein the first layer of the first actuator material is pre-stressed along a first direction and the second layer of the second actuator material is pre-stressed along a second direction, the first direction and the second direction not being aligned.
16. The method of claim 1 , further comprising:
de-activating the actuator material in the actuator film via a predetermined de-activating stimulus at locations along the first surface of the wafer and removing the stress within the actuator film.
17. The method of claim 1 , wherein
the first surface includes fully formed devices and is opposite a backside surface,
the actuator film comprises a plurality of portions, and
the actuator film is formed overtop each of the fully formed devices, each portion of the plurality of portions being separate from one another and localized to each device of said each of the fully formed devices.
18. The method of claim 1 , wherein activating the actuator material in the actuator film via the predetermined activating stimulus at the locations along the first surface of the wafer is based on a wafer shape deformation stress map for the wafer.
19. The method of claim 18 , wherein the wafer shape deformation stress map indicates stress values to mitigate across the coordinate locations along the first surface of the wafer.
20. A method of processing a substrate, the method comprising:
receiving a wafer including a first structure on a first surface of the wafer, the wafer including a shape;
generating a wafer shape deformation stress map for the wafer and determining a first stress at a location of the first structure;
forming an actuator film on the first structure, the actuator film including an actuator material, the actuator film being sensitive to a predetermined activating stimulus, the actuator film configured to undergo a positional change in response to activation of the actuator material;
activating the actuator material in the actuator film via the predetermined activating stimulus at the location of the first structure and causing a second stress within the actuator film, the second stress caused within the actuator film mitigating the first stress at the location of the first structure; and
removing the first structure having the activated actuator film formed thereon from the first surface of the wafer.