NA0.33 EUV extension for HVM: Single-patterning 28nm metal pitch logic technology

This presentation highlights imec's efforts to extend the pitch limit of single patterning with NA0.33 EUV to a 28nm pitch metal layer in advanced logic technology, supporting the industry’s scaling momentum at a low cost. The study covers physical designs for random logic, SRAM, and analog/IO layouts, co-optimized with key technical innovations such as bright-field mask imaging, Source-Mask Optimization (SMO), Multi-Beam Mask Writing (MBMW), Metal Organic Resist (MOR) and Optical Proximity Correction (OPC). It is reported that a bright-field mask, combined with a Negative Tone Develop (NTD) process, corresponding SMO and OPC, and MBMW are key enablers for achieving an overlap depth-of-focus (oDOF) greater than 90nm across the entire design. However, because the asymmetric illumination source is required to provide sufficient imaging quality for the dense lines and spaces, tip-to-tip (T2T) spacing emerged as a hot-spot that requires design rule relaxation beyond 30nm. Another novel technology, such as directional etch, can be used as a complementary process to further scale the T2T spacing to meet the design requirements for enabling single patterning.