Microstructural insights and performance evaluation of low-damage brazed diamond wire with a tungsten core

Abstract

Silicon nitride (Si₃N₄) substrate is an essential component for the next generation of high-power semiconductor devices due to its relatively high thermal conductivity and excellent mechanical strength. Diamond wire slicing is a critical step in producing Si₃N₄ ceramic substrates. In recent years, high-performance diamond wire is badly needed for the large-scale production of Si₃N₄ ceramic substrates to address the challenges of processing quality consistency caused by tool wear. This work aims to develop a low-damage brazed diamond wire (BWD) with a tungsten core and systematically investigate its slicing performance on the slicing efficiency, slicing force, wire bow angle, wear characteristics, and sliced surface morphologies in the slicing of Si₃N₄ ceramic substrate. Experimental results indicate the brazed diamond wire with tungsten core was found to produce higher slicing efficiency, lower sawing force, smaller wire bow angle, and better wear resistance, in comparison to the electroplated diamond wire (EWD). Almost no diamond grain fell off from the brazed diamond wire after slicing, which was attributed to the strong interfacial chemical bonding between diamond grains and brazed alloys. Exposed and sharper grains enhanced the efficiency of brazed diamond wire but produced a rougher surface than nickel-coated electroplated diamond wire. The findings in this research provide guidance for the optimization of slicing tools in the mass production of Si₃N₄ ceramic substrates and serve as a reference for the other case needs for micro-textures surfaces using diamond wire slicing.