Microelectronic mechanical system and methods
First Claim
1. A method of making a spatial light modulator comprising:
- a. embedding a device layer comprising ribbon features in a sacrificial material;
b. forming a capping structure with at least one access trench;
c. etching the sacrificial material using an etchant comprising a noble gas fluoride through the at least one access trench to release the ribbon features from the sacrificial material, wherein a partial pressure of water is maintained at 5×
10−
4 Torr or less during the etching of the sacrificial material and the device layer is cooled during the etching of the sacrificial material; and
d. sealing the at least one access trench with a sealing material thereby encapsulating the ribbon features within a sealed cavity comprising a predetermined environment.
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Accused Products
Abstract
The current invention provides for encapsulated release structures, intermediates thereof and methods for their fabrication. A multi-layer structure has a capping layer, that preferably comprises silicon oxide and/or silicon nitride, and which is formed over an etch resistant substrate. A patterned device layer, preferably comprising silicon nitride, is embedded in a sacrificial material, preferably comprising poly-silicon, and is disposed between the etch resistant substrate and the capping layer. Access trenches or holes are formed in to capping layer and the sacrificial material is selectively etched through the access trenches, such that portions of the device layer are release from sacrificial material. The etchant preferably comprises a noble gas fluoride NGF2x, (wherein NG=Xe, Kr or Ar: and where x=1, 2 or 3). After etching that sacrificial material, the access trenches are sealed to encapsulate released portions the device layer between the etch resistant substrate and the capping layer. The current invention is particularly useful for fabricating MEMS devices, multiple cavity devices and devices with multiple release features.
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Citations
15 Claims
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1. A method of making a spatial light modulator comprising:
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a. embedding a device layer comprising ribbon features in a sacrificial material; b. forming a capping structure with at least one access trench; c. etching the sacrificial material using an etchant comprising a noble gas fluoride through the at least one access trench to release the ribbon features from the sacrificial material, wherein a partial pressure of water is maintained at 5×
10−
4 Torr or less during the etching of the sacrificial material and the device layer is cooled during the etching of the sacrificial material; andd. sealing the at least one access trench with a sealing material thereby encapsulating the ribbon features within a sealed cavity comprising a predetermined environment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification