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As the critical dimension of chip shrinking the semiconductor industry has developed fully from deep sub-micron to the
nano-dimension. In particular, entering the nano-dimension, lithography mask technology, among a variety of
lithography method, has become a key technology which can be applied to determine their prospect. However, the
proportions which mask cost accounted for in the costs of the entire lithography are rising. The increasing price of mask
cost caused intense competition among global mask manufacturers. How to reduce mask cost and utilizing maskless
lithography technology, the hot topic in lithography industry, have become an important subject for a lithography
engineer to study.
Based on ultraviolet light source and the digital gray-scale mask exposure technology, a new method of photolithography
is proposed. First of all, we determine the overall program of DMD digital photolithography system, analyse and design
each part of the system. On the whole, DMD digital photolithography system consists of upper-computer system, control
system and optical system. Upper-computer system is the centre of control and administration. The whole system is
supervised by host computer and subsystem is controlled by MCU respectively. Each MCU exchanges information and
data through computer interface. Control system is composed of several subsystems such as master-slave computer
interface, step motor drive, limit switch, DMD drive, solenoid valve drive subsystem. Illumination system, digital
micro-mirror device (DMD) and projection objective made up optical system. Emitted from light source, light beam goes
through illumination system and then illuminate mask (DMD). At the same time, DMD drive is performed and mask
image is shaped. Then, the image is copied to light-sensitive photoresist by projection objective, which is coated on the
substrate. Secondly, investigating key technologies such as the software design of upper-computer and control system,
we set up experimental platform to carry out the relevant tests and experiments analysis. Moreover, we complement
integration of the system and summarize system characteristics and difference. Finally, exposure experiments using
light-sensitive photoresist are carried out. The results showed that the line width of submicron, steep sidewall can be
realized by the designed system.
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