  Precision motion stages are playing a prominent role in various manufacturing
equipment. The drastically increasing demand for higher throughput in
integrated circuit (IC) manufacturing and inspection calls for the
next-generation precision stages that have light weight and high control
bandwidth simultaneously. In today's design techniques, the stage's first
flexible mode is limiting its achievable control bandwidth, which enforces a
trade-off between the stage's acceleration and closed-loop stiffness and thus
limits the system's overall performance. To overcome this challenge, this paper
proposes a new hardware design and control framework for lightweight precision
motion stages with the stage's low-frequency flexible modes actively
controlled. Our method proposes to minimize the resonance frequency of the
controlled mode to reduce the stage's weight, and to maximize that of the
uncontrolled mode to enable high control bandwidth. In addition, the proposed
framework determines the placement of the actuators and sensors to maximize the
controllability/observability of the stage's controlled flexible mode while
minimizing that of the uncontrolled mode, which effectively simplifies the
controller designs. Two case studies are used to evaluate the effectiveness of
the proposed framework. Simulation results show that the stage designed using
the proposed method has a weight reduction of more than 55% compared to a
baseline stage design. Improvement in control bandwidth was also achieved.
These results demonstrate the effectiveness of the proposed method in achieving
lightweight precision positioning stages with high acceleration, bandwidth, and
precision.
