Study of mask and wafer co-design that utilizes a new extreme SIMD approach to computing in memory manufacturing: full-chip curvilinear ILT in a day

Abstract

In advanced semiconductor memory manufacturing, mask and lithography are critical for patterning. In this paper we jointly study the benefits of a mask and wafer co-design that utilizes a new extreme single instruction multiple data (SIMD) approach to computing. Wafer results will be shown demonstrating the benefits of the approach. Unlike traditional EDA software that runs on customers’ computer farm, this new approach leverages and maximizes GPU acceleration. In this study, software speed and quality, mask writing strategy, wafer pattern fidelity and process window are examined and analyzed. Inverse lithography technology (ILT) has been seen as a promising solution to many of the challenges of advanced-node lithography, whether optical or EUV. However, the runtimes associated with this computational technique have limited its practical application. Until now, it has been used for critical “hotspots” on chips, but has not been used for entire chips. The solution to the runtime problem for ILT has been particularly vexing, as the traditional approach to runtime improvement – partitioning and stitching – has failed to produce satisfactory results, either in terms of runtime or in terms of quality. D2S has adopted an entirely new, stitchless approach, creating a holistically conceived, purpose-built system for ILT, This system includes a unique GPU-accelerated approach that emulates a single, giant GPU/CPU pair that can compute an entire full-chip ILT solution at once. This novel approach, systematically designed for ILT and GPU acceleration, makes full-chip ILT a practical reality in production for the first time. For the most advanced DRAM manufacturing using 193nm immersion lithography, every aspect of design, mask, and lithography, including quality of the process, accuracy, and turn-around-time, need to be optimized. Any new technique that significantly improve one or more elements of such complete process are welcome. Recently a number of new technologies, such as multi-beam mask writer, GPU accelerated computing for mask and wafer, are emerged and are reshaping the mask and lithography. This new stitchless full chip curvilinear ILT is applied to memory chip making. We will show mask making and wafer print results, including pattern fidelity and process window, to show the actual benefits of such technologies for semiconductor manufacturing.