Study Of Digital Maskless Lithography Technology And Large Area Exposure Method

Lithography technology is the core technology of micro-nanofabrication field, which includes integrated circuit manufacturing, printed circuit board manufacturing and MEMS components manufacturing, etc. In the 21 st century, with the rapid development of electronic information industry, the demand for integrated circuits emerges a rapid growth. Compared with foreign trade, the research of photolithography technique started late and the production level is relatively low. In order to meet domestic consumer demand, our country imports a large number of integrated circuit, which poses a great threat to the national information security and national defense security. In addition, foreign countries take strict protective measures for lithography accumulation and patents, which limits the development of domestic lithography related technologies and makes it difficult for lithography to obtain a breakthrough in the short term.In recent years, MOEMS has attracted more and more attention and is treated as a digital spatial light modulator, which is widely used in lithography. Digital spatial light modulator as lithography system graphics generator, which has the characteristics of flexibility, convenient, low cost and high production efficiency, can replace traditional optical lithography mask and show a very broad application prospects in the production of micro-optical components, integrated circuit manufacturing and PCB manufacturing industries. Compared to the lithography techniques of electron beam lithography, ion beam lithography, UV lithography, digital maskless lithography as an emerging maskless lithography technology has the advantages of low manufacturing threshold, less technical barriers, etc. It brings new opportunities for our country to break the monopoly of foreign lithography technology and develop lithography technologies with independent intellectual property rights. Even digital spatial light modulator based lithography system has high flexibility, low cost and high efficiency, but the system usually faced with low data processing speed and large area lithography stitching problems. So this paper chooses digital maskless lithography system as the research direction and studies the key technologies involved in the system design and proposes a new improved scheme for the current large-scale exposure.Firstly, this article makes a detailed introduction to lithography technology, including application background, technical processes and the principle of the various lithography and the advantages and disadvantages of the lithography. Secondly, researches on the key components of the digital maskless lithography system(digital spatial light modulator) and makes analysis of its structural characteristics, electrical properties and the principle of gradation modulation. The paper studies light source selection, both optical technology and design of the projection objective in the digital maskless lithography system. Considering the image processing speed bottleneck problems that often appears in digital lithography system and combining GPU and DMA techniques, the paper proposes an accelerated image processing architecture based on GPU. After building the local CUDA development environment, the paper utilizes corner detection algorithm which is commonly used in the lithography image processing performance to verify the system performance. Finally, after deeply studying of the large-scale exposure existing in the digital maskless lithography system, the paper proposes a scanning projection method based on gray stepping stitching method. Compared with the stepping projection method, this method can reduce the positioning accuracy requirements of the workpiece platform, and improve the exposure image refresh rate.