Method of fabricating suspended beam in a MEMS process
View Patent ↗A method of fabricating a suspended beam in a MEMS process, said method comprising the steps of: (a) etching a pit in a substrate, said pit having a base and sidewalls; (b) depositing sacrificial material on a surface of said substrate so as to fill said pit; (c) removing said sacrificial material from a perimeter region within said pit and from said substrate surface surrounding said pit; (d) reflowing remaining sacrificial material within said pit such that said remaining sacrificial material contacts said sidewalls; (e) depositing beam material on said substrate surface and on said reflowed sacrificial material; and (f) removing said reflowed sacrificial material to form said suspended beam.
1. A method of fabricating a suspended beam in a MEMS process, said method comprising the steps of:
(a) etching a pit in a substrate, said pit having a base and sidewalls;
(b) depositing sacrificial material on a surface of said substrate so as to fill said pit;
(c) removing said sacrificial material from a perimeter region within said pit and from said substrate surface surrounding said pit;
(d) reflowing remaining sacrificial material within said pit such that said remaining sacrificial material contacts said sidewalls;
(e) depositing beam material on said substrate surface and on said reflowed sacrificial material; and
(f) removing said reflowed sacrificial material to form said suspended beam.
2. The method of claim 1 , wherein said suspended beam is substantially planar.
3. The method of claim 1 , wherein all parts of said suspended beam have substantially the same thickness.
4. The method of claim 1 , wherein said suspended beam is an actuator for an inkjet nozzle.
5. The method of claim 4 , wherein said actuator is a heater element.
6. The method of claim 5 , wherein said heater element is suspended between a pair of electrodes.
7. The method of claim 1 , wherein said substrate is a silicon wafer.
8. The method of claim 7 , wherein said silicon wafer comprises at least one surface oxide layer.
9. The method of claim 8 , wherein said photoresist is removed by exposure through a mask followed by development.
10. The method of claim 1 , wherein said sacrificial material is photoresist.
11. The method of claim 1 , wherein said perimeter region comprises an area adjacent at least two of said sidewalls.
12. The method of claim 1 , wherein said perimeter region comprises an area adjacent all of said sidewalls.
13. The method of claim 1 , wherein removal of said sacrificial material from said perimeter region results in a space of less than 1 micron between said remaining sacrificial material and at least two of said sidewalls.
14. The method of claim 1 , wherein removal of said sacrificial material from said perimeter region results in a space of less than 1 micron between said remaining sacrificial material and all of said sidewalls.
15. The method of claim 1 , wherein said reflowing is performed by heating said sacrificial material.
16. The method of claim 15 , wherein said treatment comprises UV curing.
17. The method of claim 1 , wherein said sacrificial material is treated to prevent further reflow prior to deposition of beam material.
18. The method of claim 1 , wherein said beam material is etched into a predetermined configuration after deposition.
19. The method of claim 18 , wherein said further MEMS process steps comprise forming an inkjet nozzle containing said suspended beam.
20. The method of claim 1 , wherein further MEMS process steps are performed after deposition of said beam material and prior to said removal of said reflowed sacrificial material.