From a technical standpoint, the ability to create a three dimensional or 3D microstructures is of increasing importance in the field of miniaturization of mechanical or fluidic devices including optical elements, self-assembling components and tissue engineering frameworks just to name a few. Conventional photolithography is considered to be the most widely used process for micro device fabrication. However, it is not suitable for 3D fabrication due to the fact that illumination of a photosensitive layer via a photomask which is essentially a transparent plate that contains opaque, irreversible solid state features that inevitably produces qualities of standard height.
Experts have created what is called gray scale photomasks wherein light absorbing qualities are made of fluids. Unlike in traditional photomasks, the opacity of the photomask qualities can be tailored to an arbitrary number of gray scale levels, and their spatial pattern can be reconfigured in the time scale of seconds. Researchers are now able to show inexpensive fabrication of photoresist patterns that contain features of multiple and or smoothly varying heights. For instance, for a given microfluidic photomask, the developed photoresist pattern can be predicted as a function of the dye concentrations as well as photomask dimensions. For certain applications, the use of microfluidic photomasks can offer a low cost option to present gray-scale photolithography.
Photolithography is used to define critical feature size in the fabrication of the vast majority of micro devices including microelectronic circuits, micro electro mechanical systems and microfluidic devices. Importantly, the process of photolithography consists of selectively illuminating a thin photosensitive layer also known as photoresist using UV light through a mask containing opaque features such as plastic or glass. In order to overcome the limits of conventional photolithography, a selection of gray scale methods capable of creating ranges of exposure levels have been developed. Currently, gray-scale photolithography can be achieved through the use of scanning lasers, micro mirror projection displays, high energy beam sensitive glass photomasks just to name a few. For more information on the applications of microfluidic masks and other technical matters visit this site today.