Hinged MEMS diaphragm, and method of manufacture thereof
First Claim
1. A method of forming a micromechanical structure, comprising:
- forming a sacrificial layer on a surface of a substrate and walls of at least two trenches formed in the substrate, the at least two trenches having respectively different depths;
depositing a structural layer over the sacrificial layer, extending into the at least two trenches, the structural layer having a different residual compressive stress than the sacrificial layer;
selectively etching the structural layer to define a pattern having a boundary, at least a portion of the structural layer overlying a respective portion of the at least one of the at least two trenches being removed and at least a portion of the structural layer extending into the at least one of the at least two trenches being preserved at the boundary; and
removing the sacrificial layer from underneath the structural layer, and a portion of the sacrificial layer extending into a shallower depth of one of the at least two trenches, prior to removal of the sacrificial layer extending into a deeper depth of one of the at least two trenches at the structural boundary.
2 Assignments
0 Petitions
Accused Products
Abstract
A method of forming a micromechanical structure comprising, forming a sacrificial layer on a surface and walls of a trench in a substrate; depositing a structural layer over the sacrificial layer, extending into the trench, selectively etching the structural layer to define a pattern having a boundary, at least a portion of the structural layer overlying a respective portion of the trench being removed and at least a portion of the structural layer extending into the trench being preserved at the boundary; and removing at least a portion of the sacrificial layer from underneath the structural layer, prior to removal of at least a portion of the sacrificial layer extending into the trench at the structural boundary. A micromechanical structure formed by the method is also provided.
691 Citations
19 Claims
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1. A method of forming a micromechanical structure, comprising:
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forming a sacrificial layer on a surface of a substrate and walls of at least two trenches formed in the substrate, the at least two trenches having respectively different depths; depositing a structural layer over the sacrificial layer, extending into the at least two trenches, the structural layer having a different residual compressive stress than the sacrificial layer; selectively etching the structural layer to define a pattern having a boundary, at least a portion of the structural layer overlying a respective portion of the at least one of the at least two trenches being removed and at least a portion of the structural layer extending into the at least one of the at least two trenches being preserved at the boundary; and removing the sacrificial layer from underneath the structural layer, and a portion of the sacrificial layer extending into a shallower depth of one of the at least two trenches, prior to removal of the sacrificial layer extending into a deeper depth of one of the at least two trenches at the structural boundary. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of forming a micromechanical structure, comprising:
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providing a substrate having a surface and a trench formed into the surface; chemically converting an exposed portion of the substrate comprising the surface and the trench formed into the surface to a sacrificial material; depositing a layer of structural material over the sacrificial material, wherein the deposited layer of structural material extends into the sacrificial material in the trench; patterning the layer of structural material to expose portions of the sacrificial layer, said patterning retaining a portion of the deposited layer of structural material which extends into the sacrificial material in the trench under a removed portion of the structural material; etching the substrate to expose a portion of the sacrificial material under the structural material not extending into the trench; selectively etching the sacrificial material not extending into the trench before etching at least a portion of the sacrificial material extending in the trench, such that the structural material extending into the trench counters flexure of adjacent layers of the structural material and the sacrificial material, having respectively different residual stresses, and a remaining portion of the sacrificial material the tethers a suspended portion of the structural material over an opening formed in the substrate to a surrounding portion of the substrate, wherein the trench comprises at least two trenches, having different depths, the method further comprising removing at least the sacrificial material from a trench having a shallower depth prior to removal of at least a portion of the sacrificial material from a trench having a deeper depth. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification