Pattern-transfer process for forming micro-electro-mechanical structures
First Claim
1. A photolithographic process sequence for manufacturing MEMS structures from a first material layer of a first-material-layer thickness disposed over and in contact with a second material layer, the sequence comprising:
- a. forming a mask over the first material layer, wherein the mask leaves portions of the first material layer exposed;
b. etching the first material layer in the exposed portions to a first depth less than the first-material-layer thickness, wherein the masked portions form a raised pattern defined by recessed areas formed in the exposed portions;
c. removing at least a portion of the mask, leaving at least a portion of the raised pattern and the recessed areas exposed; and
d. etching the exposed raised pattern and recessed areas of the first material layer until the second material layer is exposed in the recessed areas, leaving the pattern affixed to the second material layer.
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Accused Products
Abstract
Described is a photolithography “pattern transfer” process for forming Micro-Electro-Mechanical Systems (MEMS) structures. A first material layer is patterned so that raised portions of the layer define features of a MEMS structure to be formed. The resulting pattern is then “transferred” to the surface of a second material layer by etching the top surface of the first material layer, including the raised portions and the valleys defined between the raised portions, until the second layer is exposed between the raised portions.
41 Citations
18 Claims
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1. A photolithographic process sequence for manufacturing MEMS structures from a first material layer of a first-material-layer thickness disposed over and in contact with a second material layer, the sequence comprising:
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a. forming a mask over the first material layer, wherein the mask leaves portions of the first material layer exposed;
b. etching the first material layer in the exposed portions to a first depth less than the first-material-layer thickness, wherein the masked portions form a raised pattern defined by recessed areas formed in the exposed portions;
c. removing at least a portion of the mask, leaving at least a portion of the raised pattern and the recessed areas exposed; and
d. etching the exposed raised pattern and recessed areas of the first material layer until the second material layer is exposed in the recessed areas, leaving the pattern affixed to the second material layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A photolithographic method of patterning a first material layer over a second material layer, the first material layer being of a thickness and having a first surface in contact with the second material layer and a second surface, the method comprising:
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a. forming a mask over the second surface of the first material layer, wherein the mask leaves portions of the second surface exposed;
b. etching the first material layer in the exposed portions to a first depth less than the thickness of the first material layer, wherein the masked portions form a raised pattern defined by recessed areas formed in the exposed portions;
c. removing the mask, leaving the raised pattern and the recessed areas exposed; and
d. etching the raised pattern and recessed areas of the first material layer until the second material layer is exposed in the recessed areas, leaving the pattern affixed to the second material layer. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A micro-machining method for patterning a first material layer over a second material layer, the first material layer being of a thickness and having a first surface in contact with the second material layer and a second surface, the method comprising:
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a. forming a first mask over the second surface of the first material layer, wherein the first mask leaves portions of the second surface exposed;
b. etching the first material layer in the exposed portions to a first depth less than the thickness of the first material layer, wherein the masked portions form a raised pattern defined by recessed areas formed in the exposed portions;
c. forming a second mask over a first portion of the raised pattern, leaving a second portion of the raised pattern and the recessed areas exposed; and
d. etching the second portion of the raised pattern and recessed areas of the first material layer until the second material layer is exposed in the recessed areas, leaving the pattern affixed to the second material layer, wherein the second mask protects the first portion of the raised pattern from the etching of (d), leaving the second portion of the raised pattern thinner than the first portion of the raised pattern. - View Dependent Claims (15, 16, 17, 18)
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Specification