Inside inkjet-printer heads, a silicon chip is used as a barrier between the orifice plate, which contains hundreds of
nozzles, and the ink reservoir. The silicon chips used to create the barriers have to be drilled. The conventional
manufacturing technique (sandblasting) does not anymore provide satisfactory results for the new generation of printers.
The water-jet-guided laser, a hybrid technology which uses a water jet to guide a laser beam, has recently been adapted
to this application, showing very promising results combining high processing speed and quality.
Today's OLED manufacturers need high-precision, fast tools to cut the metal screens used to deposit the
electroluminescent layers onto the substrate. Conventional methods -tching and dry laser cutting - are not satisfying
regarding the demands of high-definition OLED displays. A new micro machining technology, the water jet guided laser
- a hybrid of laser and water jet technologies that has been actively used in recent years in the electronic and
semiconductor field - is now available to OLED manufacturers. This technology represents a significant improvement in
screen, mask and stencil cutting, as it combines high precision and high speed. It is able to cut small apertures with
totally clean edges (no dross or slag), as the water jet removes the particles and a thin water film is maintained on the
material surface during the process. Because the water jet cools the material between the laser pulses, the cut material is
free of any thermal stress. The water jet guided laser is also a very fast process: as an example, rectangular slots can be
cut in 30 to 50 microns thick stainless steel or nickel at a rate between 25'000 and 30'000 holes per hour.
For many years, wafer cutting has posed a challenge to laser-based cutting techniques because of the brittle nature of semiconductors and the exacting requirements for cleanliness. Since conventional laser cutting generates a strong heat-affected zone and a large amount of particles, abrasive sawing is currently the standard process for semiconductor wafer dicing. However, abrasive sawing can no longer fulfill the demands of new, emerging types of semiconductor devices like those based on thin wafers and compound semiconductors. New separation methods are investigated here. The water jet guided laser is a relatively recent technology that offers not only a significantly reduced heat-affected zone but also a cleaner wafer surface. This is due, first, to the water jet, which cools the material between the laser pulses and removes a significant amount of molten material generated by laser ablation. However, the system has recently been upgraded by adding a device that covers the entire wafer surface with a well-controlled thin water film throughout the cutting process. The few generated particles are thus kept in suspension and will not deposit on the wafer surface.
Unlike conventional laser-based technologies, the water jet guided laser does not generate heat damage and contamination is also very low. The negligible heat-affected zone is one reason why die fracture strength is higher than with sawing. This paper first presents the water jet guided laser technology and then explains how it differs from conventional dry laser cutting. Finally, it presents the results obtained by three recent studies conducted to determine die fracture strength after Laser-Microjet cutting.