Demonstration of full field patterning of 32 nm test chips using EUVL

摘要

EUV lithography is considered one of the options for high volume manufacturing (HVM) of 16 nm MPU node devices [1]. The benefits of high k_1(～0.5) imaging enable EUVL to simplify the patterning process and ease design rule restrictions. However, EUVL with its unique imaging process - reflective optics and masks, vacuum operation, and lack of pellicle, has several challenges to overcome before being qualified for production. Thus, it is important to demonstrate the capability to integrate EUVL into existing process flows and characterize issues which could hamper yield. A patterning demonstration of Intel's 32 nm test chips using the ADT at IMEC [7] is presented, This test chip was manufactured using processes initially developed with the Intel MET [2-4] as well as masks made by Intel's mask shop [5,6]. The 32 nm node test chips which had a pitch of 112.5 nm at the trench layer, were patterned on the ADT which resulted in a large k_1 factor of 1 and consequently, the trench process window was iso-focal with MEEF = 1. It was found that all mask defects detected by a mask pattern inspection tool printed on the wafer and that 90% of these originated from the substrate. We concluded that improvements are needed in mask defects, photospeed of the resist, overlay, and tool throughput of the tool to get better results to enable us to ultimately examine yield.