2001 update on the SEMI Standards Mask Qualification Terminology Task Force

Abstract

At BACUS2000 this initiative towards a common use of terminology in photomask manufacturing and application, has been introduced. A proposed standard has been achieved for one-dimensional terminology, such as feature width uniformity, feature linearity, etc. The special approach of the document is that it includes a list of mandatory information to clarify a number given, e.g. as measurement result or as budget. The main target of the document is to serve as guideline for usersupplier communication in the field of photomasks. The present focus in the Task Force is on terminology for twodimensional mask metrology. This includes corner rounding, line-end, shortening, edge roughness, etc. Such terms are already in use and described in literature, but a quantitative comparison is complicated without a full understanding of the technique and sample size used. In addition, the Task Force is discussing an approach by which the fidelity of a mask feature can be quantified. The challenge for use in benchmarking is to find a representative set of features. The suggested pattern fidelity quantification is a first step to allow an assessment of the printing performance of real reticles, taking limitations of the achieved pattern fidelity caused by the mask making process into account.

Reticle quality needs for advanced 193-nm lithography

“…As claimed in [5], there was (and still is) a strong need for a uniform use of terminology to qualify a mask for linewidth control and the above mentioned pattern fidelity related issues. For linewidth control the need was the highest, as the mask requirement table in the SIA (former ITRS) roadmap, which was the only widespread and commonly used document serving as a guideline for commercial activity between mask vendors and mask users, was not clear enough.…”

“…In the proposed SEMI document a special approach is taken in which, rather than just a definition, a list of mandatory information is listed as part of the definition, which needs to be provided to clarify how a certain measurement result was obtained [5,6]. In a later stage this terminology and the approach taken will also allow the determination of error budgets for all existing and suggested additional error sources, based on a correlation of the reticle quality to the printed image on wafer (reticle quality printability).…”