DLideas 6: LithographyMorgan Humburg
The DLideas series focuses on current developments in the world of DLP and emerging applications using the technology.
This article discusses how DLP® Technology is being used in the field of lithography – specifically maskless lithography, where structures like integrated-circuits are fabricated at a nanometer-scale size. DLP®’s ability to project predetermined mirror patterns onto photosensitive material eliminates the need for expensive, inflexible photomasks and is helping move the industry forward as a result.
Lithography, the process of printing from a plane surface on which the image to be printed is ink-receptive and the blank area is ink-repellent, is one of the fastest emerging applications using DLP® technology. Micro or nano-lithography refers specifically to the branch of nanotechnology concerned with the study and application of fabricating nanometer-scale structures.
With DLP® using digital micromirror devices, you can reflect a predetermined mirror pattern onto a photosensitive material called a photoresist. In this case, the DMD acts as a dynamic mask and the final pattern is created directly from a digital representation on a computer by controlling an electron beam as it scans across a resist coated substrate. This is often referred to as maskless lithography. In this method, the radiation used to expose a photoresist is not projected from, or transmitted through, a photomask. Instead, the radiation is focused to a narrow beam, then used to directly write the image into the photoresist one or more pixels at a time.
Examples of maskless lithography include digital exposure or direct imaging, printed circuit board patterning and manufacturing, flat panel displays, laser marking, computer-to-plate printing, solder masks, ball grip arrays, chipscale package, and real-time barcode marking.
Most lithography applications usually require a custom-produced hard photo mask to be manufactured, which is very time consuming, expensive, and limits functionality and flexibility. By using DMDs, you can directly expose a pattern onto the photoresist films without the need for any expensive photo masks. With DLP®, lithography patterns can also be dynamically changed on the fly through digital methods without having to physically change out the mask or print plates.