US 5,665,251 A · RIE image transfer process for plating

Abstract

A method is provided for constructing well defined plated miniature metallic structures. A seedlayer may be formed over an insulative layer such as a gap layer of a write head. A protective layer, such as alumina or silicon dioxide, is formed on top of the seedlayer to protect it from a subsequent reactive ion etching (RIE) step. A relatively thick layer of material, such as polymeric photoresist, is formed on top of the protective layer, the thick layer being of a type of material which can be patterned by reactive ion etching. By photolithography, an RIE mask, such as a thin layer of patterned metal, is formed on top of the relatively thick resist layer. The pattern of the mask corresponds to the desired shape of the metallic structure to be formed by plating. After masking the relatively thick layer the relatively thick layer is anisotropically etched by RIE. After the thick layer is RIE'd the protective layer on top of the seedlayer portion to be plated is removed by an etchant such as an aqueous alkaline etchant containing EDTA. It is important that the polymeric photoresist not be attacked by this etchant since it would undercut the high definition required for the metallic structure. After the protective layer portion is removed electrodeposition takes place to plate the desired metallic structure on the seedlayer portion. After plating the remaining relatively thick layer can be removed by reactive ion etching and the remaining protective layer can be removed by the aforementioned etchant containing EDTA to leave the desired freestanding metallic structure with miniature high resolution features.

Claims39

Dependent claims

A method of forming a miniature metallic structure over a nonconductive material layer by plating with a pattern shaped to correspond to said miniature metallic structure, the method comprising the steps of:

depositing a seedlayer on the nonconductive material layer;
depositing a protective layer on the seedlayer for protecting the seedlayer;
depositing a relatively thick layer of material on the protective layer;
the material of the relatively thick layer of material being of a type which, can be patterned by reactive ion etching, which is a first etch, and which, after patterning, is not removable by a second etch;
the seedlayer being of a type of material which is damaged by said first etch and is not removable by said second etch;
the protective layer being of a type of material which is not removable by said first etch but is removable by said second etch;
masking a top surface of the relatively thick layer to expose a surface portion of the relatively thick layer of material;
etching the relatively thick layer of material with said first etch to remove a thickness of the relatively thick layer of material below the exposed surface portion to expose a portion of the protective layer;
etching the exposed portion of the protective layer with said second etch to expose a seedlayer portion where the miniature metallic structure is to be formed;
plating a metallic layer on the exposed seedlayer portion to form the miniature metallic structure;
the miniature metallic structure being a type of material which is not removed by said first etch;
and
removing with said first etch the relatively thick layer of material leaving the miniature metallic structure with a protective layer around it.

10 more elements

Dependencies are inferred from the claim text.

RIE image transfer process for plating

Life of this patent

RIE image transfer process for plating

Life of this patent

Abstract

Claims39