Low-rate electrochemical etch of thin film metals and alloys
AssigneeWestern Digital (Fremont), LLC
InventorsJose A. Medina, Tiffany Yun Wen Jiang, Ming Jiang
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Abstract
Embodiments of the present invention include systems and methods for low-rate electrochemical (wet) etch that use a net cathodic current or potential. In particular, some embodiments achieve controlled etch rates of less than 0.1 nm/s by applying a small net cathodic current to a substrate as the substrate is submerged in an aqueous electrolyte. Depending on the embodiment, the aqueous electrolyte utilized may comprise the same type of cations as the material being etched from the substrate. Some embodiments are useful in etching thin film metals and alloys and fabrication of magnetic head transducer wafers.
Claims14
A method for electrochemical etching, the method comprising:
- providing a substrate comprising a metal or alloy of a first material;
- providing an etching solution comprising an electrolyte of a second material;
- and
- immersing the substrate in the etching solution while applying a cathodic current to the substrate, wherein the cathodic current is applied such that the etching solution causes the first material of the substrate to etch and the etching solution causes a reduction reaction to take place and wherein applying the cathodic current to the substrate comprises increasing a current density through the substrate from a zero net current through the substrate to a first net current through the substrate, wherein the first net current is more cathodic than the zero net current.
Dependencies are inferred from the claim text.