UV EXPOSURE & MASKING SYSTEMS
The aim of UV exposure systems is to initiate the cross linkage by the activation of the PAC (PhotoActive Component) in some parts of the photoresist. This activation will change the local properties of the photoresist which after baking will be soluble or not soluble in a solvent.
There are some major parameters that must be taken into account while choosing a UV source for photolithography applications. These parameters are: i) the power and the exposure time, ii) characteristics of the optical beam, iii) the light source type, and iv) the variability in time and space.
The light source type has became an important parameter only recently, because priorly mercury arc lamps were the only sources capable of providing high intensity light suitable for UV photolithography exposure. Thanks to the advances in LED technology, UV-LED lamps have become a very attractive alternative to the expensive and high energy-consuming mercury lamps.
Along with the ecological and security aspects, the technical advantages of UV-LEDs as compared with traditional mercury lamps are numerous and significant for photolithography. A foremost advantage of UV-LEDs is that they operate with consistent emission for very long lifetimes and with a light 100% monochromatic. As a result, daily calibration and maintenance are not required. Furthermore, by being more energy efficient, UV-LEDs have reduced heating, which greatly simplifies system cooling. In addition, unlike mercury lamps which need about 30 minutes to warm-up and stabilize before use, UV-LEDs are instant-start, and thus can be rapidly switched on and off. Finally, UV-LEDs have an average life time of 20.000 hours which is nearly 10 times longer when compared with mercury lamps.
Rotalab offers a wide range of high-end UV exposure and masking systems for research and production.