For RF and photonics devices, gold plating plays a vital role in device performance. High-speed plating in a gold sulfite bath is sensitive to localized flow vectors due to the relatively slow diffusion rate of gold complex ions. As a result, you may find that sub-optimal electrolyte flow profile can lead to non-uniform deposition rates across the wafer. In immersion platers, and most fountain plater systems, a very low plating rate must be used to overcome this issue. Example of a high-step coverage gold through-wafer via TWV plating. Conformal gold Through Wafer Via (TWV) plating. Technical Data Wafer Materials Silicon, GaAs, GaN on Si, GaN on Sapphire, Sapphire, Transparent Substrates, and more Flow Rate 10-60 lpm (dependent on wafer size) Plating Rate Up to 150μm/minute (dependent on chemistry) Within-Wafer Uniformity<3% (range 2*mean) Wafer-to-Wafer Uniformity 1% (mean-to-mean) Step Coverage 70-93% (dependent on aspect ratio) Roughness<2kÅ
