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Superconformal Filling Composition and Superconformally Filling a Recessed Feature of an Article
Patent Number: 10,889,908
Patent Description
This invention disclosure details a process for filling trenches and vias with gold for fabrication of gratings used in x-ray imaging applications. The process fills the features preferentially from the bottom, permitting seam-free and void-free filling. Gold is deposited almost exclusively within the recessed features, with minimal deposition on the field, minimizing waste and reducing post deposition processing time. The electrolyte includes no lead-based additives as well as no polymer additives. The electrolyte is non-cyanide and nearly neutral. Deposition is conducted at room temperature.
Invention
Superconformally filling a recessed feature includes: contacting the recessed feature with superconformal filling composition that includes: Au(SO3)23− anions; SO32− anions; and Bi3+ cations; convectively transporting Au(SO3)23− and Bi3+ to the bottom member of the recessed feature; subjecting the recessed feature to an electrical current to superconformally deposit gold from the Au(SO3)23− on the bottom member relative to the sidewall and the field, the electrical current providing a cathodic voltage; and increasing the electrical current subjected to the field and the recessed feature to maintain the cathodic voltage between −0.85 V and −1.00 V relative to the SSE during superconformally depositing gold on the substrate to superconformally fill the recessed feature of the article with gold as a superconformal filling of gold, the superconformal filling being void-free and seam-free.
Features
Gold is deposited almost exclusively within the recessed features, with minimal deposition on the field, minimizing waste and reducing post deposition processing time. The electrolyte includes no lead-based additives as well as no polymer additives.