CHEMICAL NICKEL PLATING METHOD FOR THERMOELECTRIC SEMICONDUCTOR

摘要

PROBLEM TO BE SOLVED: To provide a chemical nickel plating method for a thermoelectric element module including P type elements and N type elements mixedly in which P type elements and N type elements are plated simultaneously through one processing. SOLUTION: A thermoelectric element is subjected to alkaline defatting and cleaned with hydrofluoric acid. Subsequently, N type elements are subjected to surface conditioning using CPL based polishing liquid in a first stage etching followed by second stage etching using an etching liquid of nitric acid/acid ammonium fluoride/hydrogen peroxide added with a trace of propylalchol and lauryl sodium sulfate as a countermeasure against gas generation. The N type elements are subjected to removal of oxide film and chemical polishing in the second half of etching process. The P type elements are subjected to dissolution of formed oxide film and chemical polishing. Subsequently, black oxide film formed immediately after etching is cleaned ultrasonically in alkaline solution and removed in desmut process. Finally, chemical nickel plating is performed following to sensitizing/activating process.