Product Code: ICA13_M201

Dicing of Thin Si Wafers with a Picosecond Laser Ablation Process
Authors:
Christian Fornaroli, Fraunhofer ILT; Aachen Germany
Jens Holtkamp, Fraunhofer Ilt; Aachen
Arnold Gillner, Fraunhofer Ilt; Aachen
Presented at ICALEO 2013

These days common way to produce electrical components like LEDs or computer chips is a batch process. Therefore a lot of identical components are processed parallel on one big wafer and
eventually each chip has to be singulated. Mechanical sawing with diamond blades have been used for a long time but as the wafer material is
getting thinner and the chip size smaller, this classical process is replaced by laser based dicing processes. Especially the mechanical load and the large kerf width are serious disadvantages of a mechanical dicing process. A reduction of the kerf width would lead to a much higher yield of chips.

Thus dicing of thin wafers with a picosecond laser ablation process provides very promising advantages compared to the state of the art. However the process parameters are not completely known and so the goal of this paper is to investigate the cutting process with regards to thin dicing kerfs, little material damage and highest throughput. To achieve these objectives various laser and process parameters like wavelength, pulse overlap and pulse energy are analyzed. Furthermore fast beam deflection with a polgon scanner together with beam splitting by DOEs is tested to increase the cutting speed.