Research Of Chemical Metallization Technology On Electronic Substrate

With the popularization of emerging application scenarios in recent years,high-frequency,high-speed and high-density integration has become the development trend of today’s electronic products,which puts forward a high requirement for thermal properties and insulating properties of substrates.A new circuit substrate typified by an Al₂O₃ceramic substrate and a PPE resin substrate can better meet these requirements than a conventional electronic substrate.However,due to the large chemical inertness of these substrate components and the small roughness of the surface,there is no good physical or chemical bonding site between the metal layer and the substrate,so that there are some drawbacks between the two materials,such as the adhesion is not strong enough.Therefore,how to get a high-quality conductive metal layer on the surface of electronic substrates in a simply and safety way is still an urgent need and a significant challenge.The main research of this paper are about this.（1）By comparison experiments,the pretreatment process of Al₂O₃ ceramic substrate treated with molten sodium hydroxide at 460℃ for 4 minutes is preferred.After the treatment,the surface roughness of the Al₂O₃ ceramic substrate is added,and the wettability of the aqueous solution is improved.（2）Through the comparison experiment,the acid potassium permanganate solution is preferably immersed at 45℃ for 10 minutes as a pretreatment process for the PPE resin substrate.It is found that the benzyl group of the PPE is oxidized to a carboxylic acid group after the treatment.The substrate polarity is increased and the hydrophilicity is improved.（3）The dopamine solution was used to modify the Al₂O₃ ceramic substrate and the PPE resin substrate.The reaction temperature was determined to be 10℃,and the optimal reaction time was 24 hours.It was confirmed by SEM,XPS,FT-IR and other tests that adsorptive functional groups including amino and phenolic hydroxyl groups are well bonded on the surface of inert substrate,which improved the bonding force between the metal layer and the substrate.（4）A metal copper layer was deposited on the surface of the substrate by electroless plating.Through the characterization of the morphology and properties of the metal copper layer,the surface of the metal copper layer obtained by the process of the paper was uniform,which also has an excellent performance in crystallinity.The surface resistivity of the copper layer on Al₂O₃ ceramic substrate can be as low as 17.2 mΩ/□,after conversion,the resistivity is as low as 2.39μΩ*cm,which is only 1.43 times that of copper.The square resistivity of the copper layer on PPE resin substrate is 60.5 mΩ/□.At the same time,the adhesion between the metal layer and the substrate of the two substrates meets the highest 5B level requirement in the standard ASTM D3359-02.