Batch fabrication of MEMS scanning mirror
Methods are disclosed for manufacturing a Micro-ElectroMechanical Systems (MEMS) scanning mirror. In an embodiment, one method includes depositing a hinge material on a substrate and removing first and second portions of the substrate to form an outer frame, an inner frame, and a mirror plate in the substrate. First and second portions of the hinge material rotationally couple the outer frame to the inner frame and the inner frame to the mirror plate for rotation about first and second orthogonal axes of rotation. In another embodiment, a third portion of the substrate rotationally couples the inner frame to the mirror plate. In still another embodiment, an elastomer material is configured as a bending hinge that rotationally couples the outer frame to the inner frame.
1. A method for manufacturing a Micro-ElectroMechanical Systems (MEMS) scanning mirror, the method comprising:
depositing a hinge material on a first side of a substrate, wherein the hinge material comprises biaxially-oriented polyethylene terephthalate (BoPET);
etching the hinge material to form a hinge;
removing a first portion of the substrate from a second side of the substrate to form an outer frame in the substrate; and
removing a second portion of the substrate from the second side of the substrate to form an inner frame and a mirror plate in the substrate,
a first portion of the hinge material rotationally coupling the outer frame to the inner frame for rotation about a first axis of rotation and a second portion of the hinge material rotationally coupling the inner frame to the mirror plate for rotation about a second axis of rotation, the first axis of rotation orthogonal to the second axis of rotation.
2. The method of claim 1 , wherein the substrate comprises a silicon wafer.
3. The method of claim 1 , wherein:
the first and second portions of the hinge material are configured as torsional hinges, and
the second portion of the hinge material has a resonance frequency twice the resonance frequency of the first portion of the hinge material.
4. The method of claim 1 , further comprising:
placing a positioning structure adjacent to a side of the mirror plate corresponding to the first side of the substrate, the positioning structure configured to hold a plurality of permanent magnets in desired positions relative to the mirror plate;
mechanically coupling the plurality of permanent magnets to the side of the mirror plate corresponding to the first side of the substrate; and
removing the positioning structure.
5. The method of claim 4 , further comprising:
mechanically coupling an inductor to the outer frame adjacent to the side of the mirror plate corresponding to the first side of the substrate,
the inductor configured to:
cause a first subset of the plurality of permanent magnets to rotate the inner frame and mirror plate relative to the outer frame about the first axis of rotation, and
cause a second subset of the plurality of permanent magnets to rotate the mirror plate relative to the inner frame about the second axis of rotation.
6. The method of claim 5 , wherein:
the first subset of the plurality of permanent magnets comprises two permanent magnets positioned symmetrically about the first axis of rotation and oriented with opposing magnetic polarity to each other,
the second subset of the plurality of permanent magnets comprises two permanent magnets positioned symmetrically about the second axis of rotation and oriented with opposing magnetic polarity to each other, and
a center of a magnetic field of the inductor is oriented coaxial with an intersection of the first axis of rotation with the second axis of rotation.
7. A method for manufacturing a Micro-ElectroMechanical Systems (MEMS) scanning mirror, the method comprising:
depositing a hinge material on a first side of a substrate;
removing a first portion of the substrate from a second side of the substrate to form an outer frame in the substrate; and
removing a second portion of the substrate from the second side of the substrate to form an inner frame and a mirror plate in the substrate,
a portion of the hinge material rotationally coupling the outer frame to the inner frame for rotation about a first axis of rotation and a third portion of the substrate rotationally coupling the inner frame to the mirror plate for rotation about a second axis of rotation, the first axis of rotation orthogonal to the second axis of rotation.
8. The method of claim 7 , wherein the hinge material comprises biaxially-oriented polyethylene terephthalate (BoPET).
9. The method of claim 8 , wherein the substrate comprises a silicon wafer.
10. The method of claim 7 , wherein:
the portion of the hinge material is configured as a bending hinge,
the third portion of the substrate is configured as a torsional hinge, and
the third portion of the substrate has a resonance frequency twice the resonance frequency of the portion of the hinge material.
11. The method of claim 7 , further comprising:
placing a positioning structure adjacent to a side of the mirror plate corresponding to the first side of the substrate, the positioning structure configured to hold a plurality of permanent magnets in desired positions relative to the mirror plate;
mechanically coupling the plurality of mirrors to the side of the mirror plate corresponding to the first side of the substrate; and
removing the positioning structure.
12. The method of claim 11 , further comprising:
mechanically coupling an inductor to the outer frame adjacent to the side of the mirror plate corresponding to the first side of the substrate,
the inductor configured to:
cause a first subset of the plurality of permanent magnets to rotate the inner frame and mirror plate relative to the outer frame about the first axis of rotation, and
cause a second subset of the plurality of permanent magnets to rotate the mirror plate relative to the inner frame about the second axis of rotation.
13. The method of claim 12 , wherein:
the first subset of the plurality of permanent magnets comprises one or more permanent magnets positioned on the second axis of rotation and oriented with a common magnetic polarity to each other,
the second subset of the plurality of permanent magnets comprises two permanent magnets positioned symmetrically about the second axis of rotation and oriented with opposing magnetic polarity to each other, and
a center of a magnetic field of the inductor intersects the second axis of rotation.
14. A method for manufacturing a Micro-ElectroMechanical Systems (MEMS) scanning mirror, the method comprising:
depositing a hinge material on a first side of a substrate, wherein the hinge material covers less than all of the first side of the substrate;
depositing an elastomer material separate from the hinge material on the first side of the substrate;
removing a first portion of the substrate from a second side of the substrate to form an outer frame in the substrate; and
removing a second portion of the substrate from the second side of the substrate to form an inner frame and a mirror plate in the substrate,
etching the deposited elastomer material to form a hinge, whereby a portion of the elastomer material is configured as a bending hinge rotationally coupling the outer frame to the inner frame for rotation about a first axis of rotation,
a portion of the hinge material is configured as a torsional hinge rotationally coupling the inner frame to the mirror plate for rotation about a second axis of rotation, the first axis of rotation orthogonal to the second axis of rotation.
15. The method of claim 14 , wherein the hinge material comprises biaxially-oriented polyethylene terephthalate (BoPET).
16. The method of claim 14 , further comprising:
placing a positioning structure adjacent to a side of the mirror plate corresponding to the first side of the substrate, the positioning structure configured to hold a plurality of permanent magnets in desired positions relative to the mirror plate;
mechanically coupling the plurality of mirrors to the side of the mirror plate corresponding to the first side of the substrate; and
removing the positioning structure.
17. The method of claim 16 , further comprising:
mechanically coupling an inductor to the outer frame adjacent to the side of the mirror plate corresponding to the first side of the substrate,
the inductor configured to:
cause a first subset of the plurality of permanent magnets to rotate the inner frame and mirror plate relative to the outer frame about the first axis of rotation, and
cause a second subset of the plurality of permanent magnets to rotate the mirror plate relative to the inner frame about the second axis of rotation.
18. The method of claim 17 , wherein:
the first subset of the plurality of permanent magnets comprises one or more permanent magnets positioned on the second axis of rotation and oriented with a common magnetic polarity to each other,
the second subset of the plurality of permanent magnets comprises two permanent magnets positioned symmetrically about the second axis of rotation and oriented with opposing magnetic polarity to each other, and
a center of a magnetic field of the inductor intersects the second axis of rotation.