Sound-Assisted Crack Propagation for Semiconductor Wafering

The process of wafering silicon requires wire saws and slurries to dice blocks of metal into very thin layers but result in about 50% material loss due to kerf (the width of a saw cut). Techniques to mitigate kerf losses achieve thinner silicon wafers but propagate the crack too quickly resulting in defects within the structure that contribute to a reduction in performance. Therefore, researchers are now looking to controllably move a crack to produce a smooth, defect-free surface. Researchers at ASU have developed a technique to controllably move a crack at a speed induced by a stress localized at the crack tip to produce smooth, defect-free surfaces. A type of transducing material transmits waves through the metal block from a cut/notch created beforehand in a manner such that the acoustic frequency enables users to advantageously lengthen the crack. The amplitude creates a focus on the crack tip that ultimately enables control of the speed of crack propagation, mitigating defects within the structure. Overall, the technique allows users to leverage sound to control cracks on a wafer and results in a smooth, defect free surface with minimized material losses. Potential Applications Integrated Circuit Manufacturing Solar Cells Micro and Nano Electromechanical Systems Benefits and Advantages Kerfless The technique uses sound to help propagate cracking of the wafer, mitigating losses and defects associated with a saw cut Effective The technique produces a smooth, defect-free surface essential to manufacturing wafers Improved Precision The crack propagation is sound-assisted which allows the user to lengthen the crack to produce the desired wafer type Download Original PDF For more information about the inventor(s) and their research, please see: Dr. Mariana Bertoni's directory webpage For more information about related technologies, please see: M11-139P: Laser Wafering of Silicon Solar Cells