PHASE-SHIFTING LITHOGRAPHY - MASKMAKING AND ITS APPLICATION

The use of phase-shifting masks (PSMs) allows substantial improvement in resolution and depth-of-focus of optical systems. Before the advant ages of PSMs can be realized in a production process, several problems of mask technology must be solved. In order to advance PSMs from a de velopment tool to a production tool for very large scale integration ( VLSI) devices, the technologies concerning mask fabrication, mask insp ection, and mask repair have been investigated. A silicone-based resis t has been developed for simplifying the mask fabrication processes. T he printability and detectability of shifter defects have been investi gated in order to specify the requirements of systems of PSM manufactu re and inspection. The developed silicone-based resist has been applie d for mask defect repair. These technologies can bring PSMs closer to being a practical production tool for VLSI. To verify the effectivenes s of PSMs for device manufacturing, PSMs have been successfully applie d to gate definition of a high-speed GaAs field effect transistor, con tact hole fabrication, and storage node (cell capacitor) fabrication o f a dynamic random access memory device.