The wafer manufacturing industry has increased pattern complexity of the main feature and sub-resolution assist feature (SRAF) required for improving the EUV lithography process window and enabling the leading-edge technology nodes. In parallel, Inverse Lithography Technology (ILT) and its requirements of curvilinear data structure has gained momentum in recent years, putting the pressure on mask makers, in particular the mask writer. To fulfill the curvilinear feature requirements of high pattern resolution and large data volume, the mask writer needs to develop innovative techniques and update its error compensation strategies. In this paper, we will investigate the pattern resolution, local critical dimension uniformity (LCDU), and line edge roughness (LER) and explore the projected improvements in multi-beam writer technology and highlight its capability against EUV lithography requirements. We will also investigate the role of resist and process on these critical mask metrics to illustrate the overall performance against wafer requirements.
EUV mask exposure tests were conducted at Intel Mask Operation (IMO) on a MBMW201 multi-beam writer to study the effects of writing beam diameter and associate blurs, mask exposure dose, and photoresist on pattern resolution, LCDU, and LER. An analytical model was also used to predict the trend and determine the dependency of these lithographic metrics on the writer exposure conditions.Several equipment suppliers are proposing new architectures for mask patterning. These approaches share the characteristic of some level of parallelism to solve the throughput challenge caused by increasing mask pattern complexity. Although parallelism is a proven approach in laser mask writers, it has not been integrated into an e-beam platform. All of the approaches for multibeam e-beam architectures have unique technical difficulties. In some cases, suppliers have produced proof of concept results to demonstrate the feasibility of their approach and address key technical risks. Although these results are encouraging, it is clear that they need more time and industry assistance to produce a commercially worthy mask writer.
Key drivers will be considered. Proposed evolutionary extensions of the current architecture will be evaluated. The need for revolutionary architectures to satisfy future mask patterning will be explored.
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