Curvilinear masks: an overview

Curvilinear masks are coming. With multi-beam mask writers in production, leading edge mask shops are able to write curvilinear masks in the same mask write times as any Manhattan shapes. It has been proven that curvilinear mask shapes produce the best wafer process windows. It is widely anticipated by the luminaries of the industry that curvilinear ILT shapes either is already or will be used at least for hotspots in some leading-edge layers before 2023 for both 193i and EUV masks. This paper introduces the session on curvilinear masks and curvilinear mask formats by surveying the constraints and considerations around introducing curvilinear masks to mask manufacturing. This paper reiterates that curvilinear MRC can be significantly less complex. Other aspects of the mask infrastructure including metrology, inspection and repair will be also discussed.