Psi Star

Daniel J Barnett

Norvell J Nelson

James F Battey

Copper etching process and product particularly suitable for use in the manufacture of printed circuit boards. The copper is etched in a liquid etchant, and the crystal structure of the copper is selected and carefully controlled to provide an anisotropic etch and a vertical-to-lateral etching ratio greater than 1:1. In one disclosed embodiment, the etching solution contains nitric acid, copper nitrate or sulfuric acid, a polymer and a surfactant, and the copper has a top surface crystal structure with predominantly (111) orientation. In another disclosed embodiment, the etching solution contains hydrogen peroxide and sulfuric acid, and the copper foil has a top surface crystal structure with predominantly (311) and (511) orientations and/or (111) orientation. A printed circuit board manufactured in accordance with the invention has a copper foil with a crystal structure selected to provide anisotropic etching and a vertical-to-lateral etching ratio greater than 1:1 with a given etching solution bonded to a substrate, with portions of the copper foil being etched away by the etching solution to form the desired foil pattern.

Copper etching process and product

Copper etching process and product particularly suitable for use in the manufacture of printed circuit boards. The copper is etched in a liquid etchant, and the crystal structure of the copper is selected and carefully controlled to provide an anisotropic etch and a relatively high vertical-to-lateral etching ratio. In one disclosed embodiment, the etching solution contains nitric acid, copper nitrate or sulfuric acid, a polymer and a surfactant, and the copper has a top surface crystal structure with predominantly (111) to (200) orientations and relatively little (220) orientation. In another disclosed embodiment, the etching solution contains hydrogen peroxide and sulfuric acid, and the copper foil has a top surface crystal structure with predominantly (311) and (511) orientations and/or (111) and (200) orientations. A printed circuit board manufactured in accordance with the invention has a copper foil with a crystal structure selected to provide anisotropic etching and a relatively high vertical-to-lateral etching ratio with a given etching solution bonded to a substrate, with portions of the copper foil being etched away by the etching solution to form the desired foil pattern.

Copper etching process and product particularly suitable for use in the manufacture of printed circuit boards. The copper is etched in a liquid etchant, and the crystal structure of the copper is selected and carefully controlled to provide an anisotropic etch and a relatively high vertical-to-lateral etching ratio. In one disclosed embodiment, the etching solution contains nitric acid, copper nitrate or sulfuric acid, a polymer and a surfactant, and the copper has a top surface crystal structure with predominantly (111) and (200) orientations and relatively little (220) orientation. In another disclosed embodiment, the etching solution contains hydrogen peroxide and sulfuric acid, and the copper foil has a top surface crystal structure with predominantly (311) and (511) orientations. A printed circuit board manufactured in accordance with the invention has a copper foil with a crystal structure selected to provide anisotropic etching and a relatively high vertical-to-lateral etching ratio with a given etching solution bonded to a substrate, with portions of the copper foil being etched away by the etching solution to form the desired foil pattern.

Growing community of inventors

San Jose, CA, United States of America

Daniel J Barnett