Method of reducing stress-induced mechanical problems in optical components
OwnerLuc Ouellet, Jonathan Lachanceinventors
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Abstract
A method of making optical quality films is described. A silica film is deposited on a wafer by PECVD (Plasma Enhanced Chemical Vapor Deposition). The deposited film is then subjected to a first heat treatment to reduce optical absorption, wafer warp, and compressive stress. A second film is deposited. This step is then followed by a second heat treatment to reduce optical absorption, wafer warp and tensile stress. The two heat treatments have similar temperature profiles.
Claims31
A method of making optical quality films, comprising the steps of:
- depositing a first silica film on a wafer by PECVD (Plasma Enhanced Chemical Vapor Deposition);
- subjecting the wafer to a first heat treatment to reduce optical absorption, wafer warp, and compressive stress;
- depositing a second silica film on the wafer by PECVD;
- and
- subsequently subjecting the wafer to a second heat treatment to reduce optical absorption, wafer warp and tensile stress.
A method as claimed in claim 24, wherein the protective layer and compensating layer are silicon nitride.
A method of making a photonic device by PECDV (Plasma Enhanced Chemical Vapor Deposition) comprising:
- a) depositing a thick first silica buffer layer on the back side of a wafer;
- b) depositing a thick silica buffer layer on the front side of said wafer;
- c) subjecting the wafer to a first heat treatment to reduce optical absorption, wafer warp, and compressive stress;
- d) depositing a silica core layer;
- e) subsequently to step d subjecting the wafer to a second heat treatment to reduce optical absorption, wafer warp and tensile stress;
- and
- f) depositing a silica cladding layer on said silica core layer.
Dependencies are inferred from the claim text.