Process for integrating dielectric optical coatings into micro-electromechanical devices
First Claim
1. A process for fabricating a deflectable optical MEMS structure having a dielectric coating, the process comprising:
- forming a device layer;
depositing a multilayer reflective dielectric optical coating over the device layer;
depositing a mask layer over the device layer;
patterning the mask layer;
transferring a pattern of the mask layer into the dielectric coating; and
removing at least part of a sacrificial layer to release the device layer and form a membrane; and
installing the membrane opposite a stationary reflector to form a tunable Fabry-Perot filter.
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Abstract
A process for patterning dielectric layers of the type typically found in optical coatings in the context of MEMS manufacturing is disclosed. A dielectric coating is deposited over a device layer, which has or will be released, and patterned using a mask layer. In one example, the coating is etched using the mask layer as a protection layer. In another example, a lift-off process is shown. The primary advantage of photolithographic patterning of the dielectric layers in optical MEMS devices is that higher levels of consistency can be achieved in fabrication, such as size, location, and residual material stress. Competing techniques such as shadow masking yield lower quality features and are difficult to align. Further, the minimum feature size that can be obtained with shadow masks is limited to ˜100 μm, depending on the coating system geometry, and they require hard contact with the surface of the wafer, which can lead to damage and/or particulate contamination.
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Citations
26 Claims
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1. A process for fabricating a deflectable optical MEMS structure having a dielectric coating, the process comprising:
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forming a device layer;
depositing a multilayer reflective dielectric optical coating over the device layer;
depositing a mask layer over the device layer;
patterning the mask layer;
transferring a pattern of the mask layer into the dielectric coating; and
removing at least part of a sacrificial layer to release the device layer and form a membrane; and
installing the membrane opposite a stationary reflector to form a tunable Fabry-Perot filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A process for fabricating a deflectable optical MEMS structure having a dielectric coating, the process comprising:
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forming a device layer;
depositing a multilayer reflective dielectric optical coating over the device layer;
depositing a mask layer over the device layer;
patterning the mask layer;
transferring a pattern of the mask layer into the dielectric coating; and
removing at least part of a sacrificial layer to release the device layer; and
wherein the step of transferring the pattern of the mask layer into the dielectric coating comprises removing the mask layer and portions of the dielectric coating on the mask layer. - View Dependent Claims (15, 16, 17)
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18. A process for fabricating a mirror of a tunable Fabry-Perot filter, the process comprising:
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depositing a multilayer reflective dielectric optical coating;
depositing a mask layer;
patterning the mask layer;
transferring a pattern of the mask layer into the dielectric coating to thereby form the mirror of the tunable Fabry-Perot filter. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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Specification