In prior work, the capability of novel nanomachining processes to repair TaN EUV absorber materials was shown using 1.8 aspect ratio (AR) AFM tips in line and space patterns down to 90 nm half-pitch. While these repair results were well within the requirements for EUV printability, they only demonstrated the capability to repair an absorber material which has become obsolete with the rapid development of EUVL technology. The introduction of boron into the absorber chemistry indicates a significant increase in the hardness of this material which can be a significant factor in tip deflection in nanomachining. In this work, test repair results are shown for an advanced EUV absorber stack containing a TaBN formulation. The repair dimensional accuracy and repeatability are analyzed along with the throughput and tip wear rates for this nanomachining process. The capability of the BitClean process to clean and finish these repairs will also be shown for this absorber type.
Photomask technological innovation has entered a new renaissance at the cutting edge due to the transition from 193 nm to extreme ultraviolet (EUV) in high volume production. EUV has allowed the manufacture of smaller and smaller features on the mask with more complex multilayer material stacks that allow for little dimensional error in both patterning and defect repair. To meet these, and other challenges, work has continued to develop material independent AFM nanomachining processes that enable next-generation tips with increasing aspect ratios. Repair results from the current best of breed process, a novel and advanced nanomachining technique, will be analyzed on the latest platforms for production. Data will be reviewed to show the process capability for single pass repair on EUV patterns using 1.8 aspect ratio (AR) NanoBits® while also looking forward to implementation to higher AR NanoBits. The process will be evaluated for dimensional control to target, cleanliness, tip wear, and throughput in defect repair in single-digit nanometer technology node patterns.
Photomask technological innovation has entered a new renaissance at the cutting edge due to the transition from 193 nm to extreme ultraviolet (EUV) in high volume production. EUV has allowed the manufacture of smaller and smaller features on the mask with more complex multilayer material stacks that allow for little dimensional error in both patterning and defect repair. To meet these, and other challenges, work has continued to develop material independent AFM nanomachining processes that enable next-generation tips with increasing aspect ratios. Repair results from the current best of breed process, a novel and advanced nanomachining technique, will be analyzed on the latest platforms for production. Data will be reviewed to show the process capability for single pass repair on EUV patterns using 1.8 aspect ratio (AR) NanoBits® while also looking forward to implementation to higher AR NanoBits. The process will be evaluated for dimensional control to target, cleanliness, tip wear, and throughput in defect repair in single-digit nanometer technology node patterns.
Nanomachining is typically described as being a material-independent subtractive mask repair process. This is a correct statement, for the most part, since it does not require a material end-stop nor chemistries targeted to remove only a specific material. However, it is not true when considering the effect of materials being removed on the integrity of the nanomachining tip (also referred to here as NanoBitsTM). While many advanced absorber materials such as OMOG are easier to nanomachine than earlier absorber materials such as chrome and MoSi, the absorbers used in EUV have proven to be much harder and tougher (in a nanomechanical sense) while sitting atop a very fragile multilayer substrate. This work shows results from advancements on the latest nanomachining platform, nm-VI to minimize tip wear during the repair process. Consequently, this improves defect repair capability for smaller dimensions, decreases overhead from tip changeouts, decreases the cost of consumables by increasing NanoBit lifetime, and increases repair tool return-on-investment.
Nanomachining is one of the primary repair processes for leading-edge technology photomasks. Many hardware improvements have been made in successive nanomachining-tool generations to improve repair performance specifications (stability, drift, and z-depth control). However, improvement to the repair processes are still needed to address the use of the latest generation of high aspect-ratio (HAR) NanoBitsTM (1.8 AR and above). Although beneficial for repair of leading-edge photomasks, HAR NanoBitsTM exhibit greater degrees of nonlinear deflection, wear, and even breakage during traditional repair processes. In this work, the authors chronicle investigations into new nanomachining process options to enable subtractive hard defect repair with HAR NanoBitsTM down to the most advanced technology node with topographic z-depth control within ±0.5 nm and no detectable line edge, or multilayer capping layer, roughness.
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