In recent years, Quick-TAT (Turn-Around Time) in preparing masks is very important factor together with the complexity and cost in mask development and manufacturing in higher-end devices. Especially in the development phase of customer-driven devices such as SOC, MCU and so on, QTAT role of mask supply might get a larger weight in LSI business. However, overhead in workflow, system and burden of mask users (designer, etc) in mask making are significant, not to mention the increase of OPC processing time and DA cost. For responding to the efficient and precipitous manufacturing requirement even for complicated leading-edge devices, we should focus on the optimization of workflow system minimization of mask-work resources in users (designer, etc.). Therefore, new Renesas Integrated Mask Operation System (RIMOS) has been developed as making masks “Everywhen you want” supporting five key functions as follows: (1) Simple interface to input mask-making parameters on Web-based integrated system (2) Hierarchical specification system of high maintainability and capability for SEMI-P10 format (3) Easy operation to instruct build-in specification for manufacturing such as complicated CD inspection (4) Bi-directional synchronization between mask-shop and wafer-fabs MES supporting the flexible multi-pass supply of masks (5) On-line quality reporting for mask-SPC monitoring supporting. This paper shows architecture of the new system 'RIMOS' and the estimate of TAT reduction in workflow.