MEMS device and fabrication method thereof
First Claim
1. A method for fabricating a micro-electro mechanical system (MEMS) device, comprising:
- providing a first substrate with an open region, wherein the first substrate includes a front side and, opposite to the front side, a back side, and the open region includes a central region and a peripheral region adjacent to a sidewall of the open region surrounding the central region;
forming a plurality of first openings in the first substrate in the peripheral region and a plurality of third openings in the first substrate in the central region by etching the first substrate in the open region from the front side to the back side, wherein a depth of the first openings in the first substrate is larger than a depth of the third openings in the first substrate, while the depth of the first openings and the depth of the third openings are both smaller than a thickness of the first substrate;
forming a photosensitive layer, the photosensitive layer including;
a bottom portion of the photosensitive layer formed on bottom surfaces of each of the first openings and also on bottom surfaces of each of the third openings; and
a sidewall portion of the photosensitive layer formed on sidewall surfaces of each of the first openings and also on sidewall surfaces of each of the third openings;
providing a second substrate;
bonding the second substrate to the front side of the first substrate;
forming a patterned mask layer on the back side of the first substrate exposing a portion of the back side surface of the first substrate corresponding to the open region; and
forming a trench in the first substrate by a dry etching process using the patterned mask layer as an etch mask and along an etching direction from the back side of the first substrate to the front side of the first substrate, wherein the trench has a concave bottom surface towards the front side of the first substrate, and all of the bottom portion of the photosensitive layer is above the concave bottom surface of the trench and at least a portion of each of the sidewall portion of the photosensitive layer is above the concave bottom surface of the trench.
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Abstract
A method for fabricating an MEMS device includes providing a first substrate with a central region and a peripheral region, and forming a plurality of first openings in the peripheral region and a plurality of third openings in the central region by etching the first substrate from a front side. The depth of the first openings is larger than the depth of the third openings. The method further includes forming a photosensitive layer on the surfaces of the first openings and the third openings, bonding a second substrate to the front side of the first substrate, and forming a trench by etching the first substrate from a back side using a patterned mask layer as an etch mask. The trench has a concave bottom surface and exposes a portion of the photosensitive layer formed on the bottom surfaces of the first openings and the third openings.
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Citations
18 Claims
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1. A method for fabricating a micro-electro mechanical system (MEMS) device, comprising:
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providing a first substrate with an open region, wherein the first substrate includes a front side and, opposite to the front side, a back side, and the open region includes a central region and a peripheral region adjacent to a sidewall of the open region surrounding the central region; forming a plurality of first openings in the first substrate in the peripheral region and a plurality of third openings in the first substrate in the central region by etching the first substrate in the open region from the front side to the back side, wherein a depth of the first openings in the first substrate is larger than a depth of the third openings in the first substrate, while the depth of the first openings and the depth of the third openings are both smaller than a thickness of the first substrate; forming a photosensitive layer, the photosensitive layer including; a bottom portion of the photosensitive layer formed on bottom surfaces of each of the first openings and also on bottom surfaces of each of the third openings; and a sidewall portion of the photosensitive layer formed on sidewall surfaces of each of the first openings and also on sidewall surfaces of each of the third openings; providing a second substrate; bonding the second substrate to the front side of the first substrate; forming a patterned mask layer on the back side of the first substrate exposing a portion of the back side surface of the first substrate corresponding to the open region; and forming a trench in the first substrate by a dry etching process using the patterned mask layer as an etch mask and along an etching direction from the back side of the first substrate to the front side of the first substrate, wherein the trench has a concave bottom surface towards the front side of the first substrate, and all of the bottom portion of the photosensitive layer is above the concave bottom surface of the trench and at least a portion of each of the sidewall portion of the photosensitive layer is above the concave bottom surface of the trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification