Laser Grooving of Copper for Microelectronics

Copper has emerged as a critical material in the semiconductor industry due to its superior electrical and thermal conductivity.For the classical wafer separation process using a blade, the presences of copper in the dicing lane is challenging and often the copper layer needs to be removed by laser grooving to achieve a high quality blade cut.The goal of this study is to investigate the influence of the applied average power from the laser head, the feed speed of the linear stages and beam splitting using an elliptical beam on the grooving dynamics of copper.The commercially available short pulse laser system DFL7262 from DISCO, which operates at wavelength of 355 nm was used to optimize the grooving process towards highest efficiency.Different multi beam configurations were characterized in terms of grooving depth as a function of fluence, feed speed and number of overscans.In addition the average roughness is investigated for selected settings.