Thin film circuit

摘要

To improve the adhesion of a nickel layer to a valve metal layer in a thin film electronic circuit, a boundary layer is created between the valve metal and the nickel layer. The boundary layer is created by oxidizing the valve metal surface and applying the nickel layer by cathode sputtering with sufficiently high energy to cause nickel-ion migration into the valve metal oxide layer. The so-formed boundary layer improves the mechanical adhesion of the nickel layer to the valve metal layer and also prevents penetration of solder to the valve metal layer since the boundary layer acts as a diffusion barrier.