A novel mask proximity correction software combining accuracy and reduced writing time for the manufacturing of advanced photomasks

摘要

The new generations of photomasks are seen to bring more and more challenges to the mask manufacturer. Maskshopsface two conflicting requirements, namely improving pattern fidelity and reducing or at least maintaining acceptablewriting time. These requirements are getting more and more challenging since pattern size continuously shrinks and datavolumes continuously grows.Although the classical dose modulation Proximity Effect Correction is able to provide sufficient process control to themainstream products, an increased number of published and wafer data show that the mask process is becoming a nonnegligiblecontributor to the 28nm technology yield. We will show in this paper that a novel approach of mask proximityeffect correction is able to meet the dual challenge of the new generation of masks.Unlike the classical approach, the technique presented in this paper is based on a concurrent optimization of the dose andgeometry of the fractured shots. Adding one more parameter allows providing the best possible compromise betweenaccuracy and writing time since energy latitude can be taken into account as well. This solution is implemented in theInscale software package from Aselta Nanographics.We have assessed the capability of this technology on several levels of a 28nm technology. On this set, the writing timehas been reduced up to 25% without sacrificing the accuracy which at the same time has been improved significantlycompared to the existing process. The experiments presented in the paper confirm that a versatile proximity effectcorrection strategy, combining dose and geometry modulation helps the users to tradeoff between resolution/accuracyand e-beam write time.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.