Effect of BEO in the electrodeposition process of Ni/diamond composite coatings for preparation of ultra-thin dicing blades: Experiments and theoretical calculations

Abstract

Ni/diamond dicing blades is the main tool for scribe of silicon wafer at present. In order to decrease the width of dicing slot on the wafer, it is necessary to reduce the thickness of blades, and to increase the hardness, toughness and wear resistance of the Ni/diamond composite coatings in the process of electrodeposition. In this paper, 1,4-bis(2-hydroxyethoxy)-2-butyne (BEO) was used as an organic additive in the composite baths containing nickel amino-sulfonate, nickel chloride, boric acid, sodium dodecyl sulfate (SDS) and diamond particles in sizes of 3–5 µm, in order to improve the properties of Ni/diamond coatings and produce ultra-thin Ni/diamond dicing blades. The textures of Ni/diamond composite coatings were mainly Ni (200) and Diamond (111) since the addition of BEO in the baths inhibited the growth of Ni (111) and Ni (220). Quantum chemical calculations and molecular dynamics (MD) simulations showed that BEO could adsorb at the nickel surface strongly and inhibit the electrodeposition of nickel atoms. With the increase in concentration of BEO in the baths, the cathodic polarization potentials shifted to more negative direction and the thicknesses of the coatings decreased. Adding the appropriate amount of BEO (0.1–0.2 g/L) in the baths, the roughness of the coating decreased the number of individual diamond particles in the coating increased, and the hardness and the wear resistance of the coating was improved. When the thickness of Ni/diamond composite coating on aluminum alloy wheeled substrate was 15 µm, the width of its dicing slot was 22 µm. However, the addition of BEO in the bath cannot change the adhesive wear mechanism of the coating.