Research On PCB Digital Lithography Projection Optics Design As Well As Scanning And Its Control Technology

As personal electronic devices progressing toward multi-function, miniaturization, lightweight, highly-integrated, some high-end personal electronic products, such as the next generation of smart phones, iPad, iPhone, digital camera, etc., need to be produced more powerful, but more energy-efficient products by manufacturers. For the next generation of high-end personal electronics manufacturing, printed circuit board (PCB) lithography is one of the most important technology. Traditional PCB lithography uses mercury lamp and proximity exposure technology with high cost, low precision of lithography and more pollution to the environment. However, digital lithography, not only in the cost and the accuracy but also in the production efficiency and the impact on the environment, has incomparable advantage over traditional PCB lithography. So the research on digital lithography technology about PCB manufacturing has a very important significance.Based on the primary aberration theory, we design a set of lithographic projection lens with dual Gauss symmetry structure for 0.7 XGA DMD. This structure can eliminate the five primary aberration of the initial structure easily. For meeting the needs of the micron grade PCB lithography, the projection lens’magnification is 1, and can keep the precision of the objective lens at 13.68 microns with no aspheric. It consists of 8 pieces of lens, which are symmetrical about center aperture, and the structure not only can reduce the cost, but also assemble the lens in the lithography system when machining processing four lens molds.Based on the DMD digital lithography scanning technology, the oblique scan technology is proposed, it has the advantage of eliminating the DMD grid effect to improve the imaging quality. Considering the design of projection lens group, it can not only realize the integer pixel line width, but improve the resolution of the image. Lithography experiment was carried out in DMD tilt scan mode, which achieving good results of realizing the non-integer line width, compared with other methods of exposure situations, the results show the properties of surface uniform illumination, crisp lines, and edge of a steep and good linearity, which can well meet the needs of the lithography.The generation of digital maskless lithography pattern is complex, such as how to recognize line vector graphics, and convert the line vector graphics to fit each micro mirror grille graphics, as well as send these grille graphics to DMD controller for the execution of micro mirror reflection, etc., therefore we did some researches of digital lithography dynamic graphical control technology. In this paper, a method based region generating digital lithography pattern has been proposed. We introduce the method of design idea and design process, comparatively analyze the dynamic graphical control technology, and discuss the feasibility of this kind of technology.