Thin Glass laser cutting, Silicon Wafer laser Cutting

Increasing trend toward higher precision processing requires Picosend laser come out. 

Ultrafast processing

Micro marking, micro drilling

Precision cutting

Ultrafast processing benefits

The goal of micromachining is the creation of micron-scale features, such as holes, grooves and marks, with high-dimensional accuracy while avoiding peripheral thermal damage to surrounding material. In other words, precise, clean cuts and marks with high surface quality and minimal heat-affected zone (HAZ). 

Schematic illustrating the major differences between ultrafast processing and processing with longer pulse width lasers.

There are two basic mechanisms by which a laser can precision drill, scribe, cut or mark a material. Many traditional applications rely on infrared and visible Q-switched lasers, which have pulse widths in the tens of nanoseconds range, and which remove material via a photothermal interaction. Here, the focused laser beam acts as a spatially confined, intense heat source. Targeted material is heated rapidly, eventually causing it to be vaporized — essentially boiled away. 

The advantage of this approach is that it enables rapid removal of relatively large amounts of target material. Furthermore,nanosecond laser technology is mature; these sources are highly reliable and have attractive cost of ownership characteristics. However, for the most demanding tasks, peripheral HAZ damage and/or the presence of some recast material can present a limitation. This includes the delamination of surface coatings, microcracking, or changes in the bulk material properties. 

Comparison of a 200-µm-diameter hole drilled in stainless steel with a nanosecond laser (left) and a picosecond laser (right). The picosecond laser produced a cleaner hole with less recast material and a smaller heat-affected zone (HAZ). 

Previously, we employed a 355-nm nanosecond laser for laser grooving, but now we’ve switched to a 1064-nm picosecond laser and perform stealth dicing.  This allows the cutting street to be reduced in size from 25 µm, down to 14 µm. Which, in turn, results in a higher yield — that is, one can pack more devices onto a given wafer. 

Picosecond laser glass cutting: avoiding cracks and debris

This application is driven by the tremendous market growth for cellphones and tablet computers that incorporate touchscreens. There are two important trends in touchscreen display glass scribing. The first is a drive toward the use of thinner glass substrates in order to minimize the total weight of the display. The second is a need to cut curved shapes in the glass, rather than simply straight lines, in order to allow rounded edges on the display, as well as to accommodate more complex screen geometries.