Metallization of aluminum nitride by nanosecond pulsed laser radiation

The article presents the formation of a conductive layer on the surface of an AlN ceramic substrate with minimal resistance during laser treatment with nanosecond pulsed laser radiation with a wavelength of λ=1.064 microns. Estimates of the optimal parameters of laser radiation treatment with a pulse duration of 200 ns, corresponding to the lowest resistance, were obtained by conducting a complete factor experiment: pulse overlap in Ox = 95% (scanning direction), overlap in Oy =57% (step direction), energy density 170 J/cm². The work shows the metallic nature of the resistance dependences on temperature when cooled to the temperature of liquid nitrogen for samples metallized by laser radiation with a pulse duration of 4 ns at three energy density values with a temperature coefficient of resistance for the highest studied energy density of 8.3 J/cm² α=4.7× 10-3 1/K. The analysis of the copper coating applied by magnetron sputtering with a decrease in overall resistance and an increase in roughness was carried out, and it was also found that correct measurements of the adhesive strength of the copper layer to aluminum during metallization with radiation with a pulse duration of 4 ns and the adhesion of the copper layer to the AlN substrate using a scratch tester are impossible due to metal indentation deep into the ceramic, The strength of the copper coating to aluminum for radiation metallized samples with a pulse duration of 200 ns and with the highest energy density is 15 N. The results obtained can be used to increase the efficiency of the direct laser metallization of AlN substrates, which improves product quality and simplifies the technological cycle of manufacturing microelectronic devices.