WAVEGUIDE FORMATION USING CMOS FABRICATION TECHNIQUES
First Claim
1. A method of making at least one optical waveguide in a silicon substrate having a front side, a back side, and at least one ridge extending from the front side of the silicon substrate and a dielectric layer of first dielectric material deposited on the front side of the silicon substrate over the at least one ridge, the first dielectric material having a first refractive index, the method comprising:
- (A) etching a portion of the back side of the silicon substrate so as to form at least one trench in the dielectric layer via removal of the at least one ridge extending from the front side of the silicon substrate; and
(B) depositing a waveguide core material, having a second refractive index greater than the first refractive index, into the at least one trench so as to form a core of the at least one optical waveguide.
1 Assignment
0 Petitions
Accused Products
Abstract
Conventional approaches to integrating waveguides within standard electronic processes typically involve using a dielectric layer, such as polysilicon, single-crystalline silicon, or silicon nitride, within the in-foundry process or depositing and patterning a dielectric layer in the backend as a post-foundry process. In the present approach, the back-end of the silicon handle is etched away after in-foundry processing to expose voids or trenches defined using standard in-foundry processing (e.g., complementary metal-oxide-semiconductor (CMOS) processing). Depositing dielectric material into a void or trench yields an optical waveguide integrated within the front-end of the wafer. For example, a shallow trench isolation (STI) layer formed in-foundry may serve as a high-resolution patterning waveguide template in a damascene process within the front end of a die or wafer. Filling the trench with a high-index dielectric material yields a waveguide that can guide visible and/or infrared light, depending on the waveguide'"'"'s dimensions and refractive index contrast.
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Citations
38 Claims
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1. A method of making at least one optical waveguide in a silicon substrate having a front side, a back side, and at least one ridge extending from the front side of the silicon substrate and a dielectric layer of first dielectric material deposited on the front side of the silicon substrate over the at least one ridge, the first dielectric material having a first refractive index, the method comprising:
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(A) etching a portion of the back side of the silicon substrate so as to form at least one trench in the dielectric layer via removal of the at least one ridge extending from the front side of the silicon substrate; and (B) depositing a waveguide core material, having a second refractive index greater than the first refractive index, into the at least one trench so as to form a core of the at least one optical waveguide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A semiconductor device comprising:
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a silicon substrate having a front side and a back side and defining a recess extending through the silicon substrate from the back side of the silicon substrate to the front side of the silicon substrate; a dielectric layer of first dielectric material, having a first refractive index, disposed on the front side of the silicon substrate, the dielectric layer defining a trench open to the recess defined by the silicon substrate; and an optical waveguide comprising a second dielectric material, having a second refractive index greater than the first refractive index, disposed within the trench. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. A method of making at least one optical waveguide in a silicon substrate having a front side, a back side, and a first refractive index, the method comprising:
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(A) etching the front side of the silicon substrate so as to define a silicon ridge on the front side of the silicon substrate; (B) depositing a layer of dielectric material having a second refractive index lower than the first refractive index on the ridge and on at least a portion of the front side of the silicon substrate adjacent to the silicon ridge; and (C) etching a portion of the back side of the silicon substrate so as to expose a portion of the silicon ridge through the silicon substrate from the back side of the silicon substrate. - View Dependent Claims (32, 33, 34, 35)
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36. A semiconductor device comprising:
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a silicon substrate having a front side, a back side, and a first refractive index, and defining a recess extending through the silicon substrate from the back side of the silicon substrate to the front side of the silicon substrate; a dielectric layer of first dielectric material, having a second refractive index lower than the first refractive index, disposed on the front side of the silicon substrate, the dielectric layer defining a trench open to the recess defined by the silicon substrate; and silicon disposed within the trench to form a core of an optical waveguide. - View Dependent Claims (37, 38)
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Specification