Patent ID: 7738753

Claim:
A method for fabricating an integrated circuit with an integral optical coupler, the method comprising: depositing a plurality of layers on a semiconductor die comprising the integrated circuit and at least one optical waveguide, the plurality of layers comprising, in order, a silicon dioxide layer, a chemical mechanical polishing stop layer in contact with the silicon dioxide layer, and an upper silicon nitride layer in contact with the chemical mechanical polishing stop layer; etching the plurality of layers on the semiconductor die, the etching the plurality of layers forming a trench above a first end of the at least one optical waveguide; depositing, into at least a portion of the trench, a silicon based dielectric comprising at least a portion with a refractive index substantially equal to a section of optical fiber; etching the plurality of layers to the chemical mechanical polishing stop layer, by a chemical mechanical polishing process after the depositing the silicon based dielectric, the etching by the chemical mechanical polishing causing a portion of the silicon based dielectric to remain in the trench below the chemical mechanical polishing stop layer; removing, after the etching the plurality of layers to the chemical mechanical polishing stop layer, the chemical mechanical polishing stop layer; cleaving the semiconductor die substantially perpendicularly to a side of the trench so as to expose one surface of the silicon based dielectric; and joining the section of optical fiber to the one surface of the silicon based dielectric.