Laser ablative cutting of ceramics for electronics applications

摘要

Pulsed, high-beam quality lasers offer unique materials processing characteristics. In processing metals, copper vapor and pulsed Nd:YAG lasers have produced micron-scale cuts and holes with submicron heat-affected zones. Since the cost of laser photons is high and average material removal rates can be slow with ablation, high value-added applications are necessary to justify processing costs. Ceramics present a special challenge for manufacturing because of their high hardness, relatively low thermal conductivity, and brittle nature. Surface damage typically limits the strength of a ceramic part to a small fraction of its bulk strength. This work investigates the use of copper vapor and pulsed diode-pumped Nd:YAG lasers to cut precision features in ceramic substrates. Variations in laser wavelength and power, processing speed, ceramic type, and assist gas were investigated with the goal of producing < 100-(mu)m wide by 600-(mu)m deep cuts through silicon-carbide and alumina/titaniumcarbide substrates for potential use in electronics. Silicon- carbide bars 250-(mu)m wide by 600-(mu)m high by 2.5-cm long were laser cut from substrates without fracture.