Mass production of thick copper vacuum metalization on plastic parts

ESD/EMI shielding coatings based on Cu layers on plastic can be produced very effectively by sputtering. Certain principles have to be followed to obtain an adequate result in mass production. Coating speed (productivity), outgassing and plastic thickness are factors, which are interrelated. The correlation between these three factors will influence the final product, a metal coating with a defined resistance between two measuring points. Typical values for these factors were sputtering at an Ar partial pressure of 1.1 × 10−3 mbar to produce a Cu layer with a specific resistivity of about 1.5 × 10−7 Ωm at a production speed of one plastic part/s. The plastic temperature due to the heating intrinsic to sputter deposition of metals, reached about 84 °C at the thinnest areas of the plastic substrate. Coating adhesion does not take part of the correlation of production conditions and achieved coating quality and production speed. Sputter deposition will produce a well adherent Cu coating on almost any clean plastic material.