System and process to remove film from semiconductor devices
Embodiments of the present disclosure are a method of forming a semiconductor device, a method of forming a magnetic tunnel junction (MTJ) device, and a process tool. An embodiment is a process tool comprising an ion beam etch (IBE) chamber, an encapsulation chamber, a transfer module interconnecting the IBE chamber and the encapsulation chamber, the transfer module being capable of transferring a workpiece from the IBE chamber to the encapsulation chamber without exposing the workpiece to an external environment.
1. A method of forming a semiconductor device, the method comprising:
forming a magnetic tunnel junction (MTJ) layer over a bottom electrode;
forming a top electrode over the MTJ layer, the top electrode being conductive;
performing a first etch process on the MTJ layer to pattern the MTJ layer, wherein the first etch process forms a film on surfaces of the MTJ layer and the top electrode;
performing an ion beam etch (IBE) process on the MTJ layer and the top electrode, wherein the IBE process removes the film from the surfaces of the MTJ layer and the top electrode, wherein after the performing the IBE process, the top electrode has a first width and the MTJ layer has a second width, the second width being larger than the first width; and
depositing a dielectric layer on a top surface and sidewalls of the top electrode and on sidewalls of the MTJ layer, the depositing the dielectric layer being performed in-situ with the IBE process.
2. The method of claim 1 , wherein the IBE process is performed under vacuum and the depositing the dielectric layer is performed under vacuum.
3. The method of claim 1 , wherein the first etch process is a dry plasma etch process.
4. A method of forming a magnetic tunnel junction (MTJ) device, the method comprising:
forming an MTJ layer over a bottom electrode, wherein the forming the MTJ layer further comprises:
forming an anti-ferromagnetic (AFM) layer over the bottom electrode;
forming a pinned layer over the AFM layer;
forming a barrier layer over the pinned layer; and
forming a free layer over the barrier layer;
forming a top electrode layer over the MTJ layer;
selectively etching the top electrode layer to form a top electrode over the MTJ layer;
patterning the free layer of the MTJ layer with a first ion beam etch (IBE) process, wherein after the first IBE process, the barrier layer is wider than the free layer;
encapsulating the top electrode, the MTJ layer, and the bottom electrode with a first dielectric layer, the encapsulating step being performed in-situ with the first IBE process; and
before the encapsulating step, patterning the barrier layer, the pinned layer, and the AFM layer of the MTJ layer with a second IBE process, the encapsulating step being performed in-situ with the second IBE process.
5. The method of claim 4 , wherein the first IBE process stops on the barrier layer.
6. The method of claim 4 further comprising:
before the encapsulating step, forming spacers on sides of the top electrode, the forming spacers comprising:
forming a second dielectric layer over the top electrode and the MTJ layer, the second dielectric layer being formed in-situ with the first IBE process; and
patterning the second dielectric layer to remove horizontal surfaces of the first dielectric layer.
7. The method of claim 4 , wherein after the performing the first ion beam etch process, the top electrode has a first width and the barrier layer, the pinned layer, and the AFM layer of the MTJ each have a second width, the second width being larger than the first width.
8. The method of claim 4 , wherein the patterning the free layer of the MTJ layer with the first IBE process further comprises:
performing the first IBE process on the free layer at a first angle of incidence;
performing a third IBE process on the free layer at a second angle of incidence, the second angle of incidence being different from the first angle of incidence, the third IBE process being performed in-situ with the first IBE process; and
performing a fourth IBE process on the free layer at a third angle of incidence, the third angle of incidence being different from the second angle of incidence, the fourth IBE process being performed in-situ with the third IBE process.
9. The method of claim 8 , wherein the second angle of incidence is larger than the first angle of incidence and the third angle of incidence as measured from a line orthogonal to a top surface of the bottom electrode.
10. The method of claim 8 , wherein the first IBE process forms a film on sidewalls of the top electrode, and wherein the third IBE process removes the film on sidewalls of the top electrode.
11. The method of claim 1 , wherein the forming the MTJ layer further comprises:
forming an anti-ferromagnetic (AFM) layer over the bottom electrode;
forming a pinned layer over the AFM layer;
forming a barrier layer over the pinned layer; and
forming a free layer over the barrier layer.
12. The method of claim 11 , wherein the dielectric layer directly adjoins a top surface and sidewalls of the free layer.
13. A method of forming a magnetic tunnel junction (MTJ) device, the method comprising:
forming an MTJ layer over a bottom electrode;
forming a top electrode over the MTJ layer;
patterning a free layer of the MTJ layer with an ion beam etch (IBE) process, the IBE process comprising:
performing a first IBE process on the free layer at a first angle of incidence;
performing a second IBE process on the free layer at a second angle of incidence, the second angle of incidence being different from the first angle of incidence; and
performing a third IBE process on the free layer at a third angle of incidence, the third angle of incidence being different from the second angle of incidence;
encapsulating the top electrode, the MTJ layer, and the bottom electrode with a first dielectric layer, the encapsulating step being performed in-situ with the first IBE process;
before the encapsulating step and after the patterning the free layer step, forming spacers on sides of the top electrode; and
before the encapsulating step and after the forming spacers step, patterning a lower portion of the MTJ layer.
14. The method of claim 13 , wherein the second IBE process is performed in-situ with the first IBE process, and wherein the third IBE process is performed in-situ with the second IBE process.
15. The method of claim 13 , wherein the second angle of incidence is larger than the first angle of incidence and the third angle of incidence as measured from a line orthogonal to a top surface of the bottom electrode.
16. The method of claim 13 , wherein the forming the MTJ layer further comprises:
forming an anti-ferromagnetic (AFM) layer over the bottom electrode;
forming a pinned layer over the AFM layer;
forming a barrier layer over the pinned layer; and
forming the free layer over the barrier layer.
17. The method of claim 7 , wherein the top electrode is conductive.
18. The method of claim 13 , wherein the patterning the lower portion of the MTJ layer comprises performing a second IBE process.
19. The method of claim 18 , wherein after the first IBE process, the lower portion of the MTJ layer is wider than the free layer of the MTJ layer.