STP300: Electrode Potential: A Tool for the Control of Materials and Processes in Electron Device Fabrication: II. EMF Studies of the Behavior of 36 Per Cent Nickel-Iron Alloy in Hydrogen Peroxide — Formic Acid Etchants

    Feder, D. O.
    Bell Telephone Laboratories, Inc., Murray Hill, N. J.

    Howden, W. E.
    Bell Telephone Laboratories, Inc., Murray Hill, N. J.

    Huff, D. R.
    Southern Bell Telephone & Telegraph Co., Birmingham, Ala

    Richards, J. W.
    Bell Telephone Laboratories, Inc., Murray Hill, N. J.

    Pages: 10    Published: Jan 1961


    Abstract

    Mixtures of formic acid, hydrogen peroxide, and water have successfully been used to clean or etch a variety of metals for use in electron device fabrication. Although in most cases the rate of etching is easily controlled, for certain materials, such as the 36 per cent nickel-iron alloy studied, apparently minor variations in either the structure of the material or in the composition of the etchant appear to have a disproportionate effect on the etching rate.

    This paper describes the use of electrode potential measurements in predicting the etching behavior of this nickel-iron alloy (invar) and in showing how the etching (and potential) behavior is related to variations in etchant composition and metallurgical state of the alloy.

    The results indicate quite clearly the utility of emf techniques both for characterizing subtle changes in bulk metallurgical properties of the alloy and in studying the solution variables which control the etch-cleaning process. In addition, emf measurements are shown to provide a simple, sensitive technique for monitoring and controlling this type of cleaning process.


    Paper ID: STP41225S

    Committee/Subcommittee: F01.06

    DOI: 10.1520/STP41225S


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