Latest cluster performance for EUV lithography

Abstract

Previously, fundamental evaluations of the Extreme Ultra Violet (EUV) lithography process have been conducted using the CLEAN TRACK ACT™ 12 coater/developer with the ASML EUV Alpha Demo Tool (ADT) at imec. [1] [2] In that work, we confirmed the basic process sensitivities for the critical dimension (CD) and defectivity with EUV resists. Ultimate resolution improvements were examined with TBAH and FIRM™ Extreme. Moving forward with this work, the latest inline cluster is evaluated using the ASML NXE:3100 pre-production EUV scanner and the CLEAN TRACK™ LITHIUS Pro™ -EUV coater/developer. The imec standard EUV baseline process has been evaluated for manufacturability of CD uniformity control based on half pitch (HP) 27nm and ultimate resolution studies focusing on HP 22nm. With regards to the progress of the improvement for EUV processing, we confirmed the effectiveness of several novel concepts: FIRM™ Extreme10 showed increase in ultimate resolution and improvement in line width roughness (LWR) and process window; Tokyo Electron LTD. (TEL) smoothing process for roughness reduction showed 17% improvement for line and space (L/S) patterns; and finally the new dispense method reduced patterned wafer defectivity by over 50%.

Resist Materials and Processes for Extreme Ultraviolet Lithography

“…There have also been reports of reduced LWR using specific types of surfactant rinse solutions. 3,8) …”

“…3,[120][121][122] Figure 11 shows the mitigation of pattern collapse with the application of an alternative rinse solution. This advantage is also being maximized in present EUVL resist processes, where very fine patterns in EUVL will mean steep aspect ratios considering sufficient film thickness usable for etching process.…”

“…Such collaborations have led to the investigation and realization of new and exciting resist platforms 5,[11][12][13] and processes. 3,14,15) These works have also shown a number of issues and challenges that need to be considered as the semiconductor industry moves to more stringent technology nodes. 16) Against this background of such international collaboration, the EUVL symposium has been organized every year by SEMATECH, IMEC, and Selete (later EIDEC).…”

“…[1][2][3] To realize the productivity targets in this lithographic technology, EUV resist materials and their related processes play a significant role. Recent advances in these materials and process technologies are largely credited to the cooperation and focused efforts of various sectors of the resist community (e.g., industry consortia, universities, and material/ tool manufacturers).…”

“…The rank of resist technology went down to third below the mask and source technologies in 2008. With the realization of EUVL approaching, [1][2][3] the critical issues were revised to a focus area in 2008. The focus area was discussed specifically from the viewpoint of the 22 nm half-pitch insertion of EUVL in 2009.…”