Wafer Stealth Dicing

In the production of chips and microchips, it is necessary to separate the individual dies from the wafer. In this process, quality and precision are crucial for all further post-fab operations. Laser dicing has therefore become the preferred dicing technology. One variant of laser dicing is the so-called stealth laser dicing (SLD). This involves creating a modified layer within the wafer by focusing a laser below the surface, and then using a tape expander to separate the chips.

Typical challenges faced by this type of wafer dicing application are to use systems that do not introduce any additional contamination risks to the wafer, to be able to accurately position the modified layer onto both XY axes to enable the narrowest possible streets, and to maintain the focus within the wafer and track wafer distortions. At the same time, the highest possible scanning speed is necessary to ensure high throughput. As requirements continue to increase, stealth laser dicing is becoming the first choice for high-volume, microelectromechanical system (MEMS) dicing, or smaller and more complex dies. Accordingly, laser-dicing processes also demand motion systems offering both high accuracy and a high level of straightness at high velocities.