The use of phase-shifting masks (PSMs) allows substantial improvement in resolution and depth-of-focus of optical systems. Before the advantages of PSMs can be realized in a production process, several problems of mask technology must be solved. In order to advance PSMs from a development tool to a production tool for very large scale integration (VLSI) devices, the technologies concerning mask fabrication, mask inspection, and mask repair have been investigated. A silicone-based resist has been developed for simplifying the mask fabrication processes. The printability and detectability of shifter defects have been investigated in order to specify the requirements of systems of PSM manufacture and inspection. The developed silicone-based resist has been applied for mask defect repair. These technologies can bring PSMs closer to being a practical production tool for VLSI. To verify the effectiveness of PSMs for device manufacturing, PSMs have been successfully applied to gate definition of a high-speed GaAs field effect transistor, contact hole fabrication, and storage node (cell capacitor) fabrication of a dynamic random access memory device.